Male germ cells derived from the haploid secondary SPERMATOCYTES. Without further division, spermatids undergo structural changes and give rise to SPERMATOZOA.
The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA.
The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.
Male germ cells derived from SPERMATOGONIA. The euploid primary spermatocytes undergo MEIOSIS and give rise to the haploid secondary spermatocytes which in turn give rise to SPERMATIDS.
Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.
Supporting cells projecting inward from the basement membrane of SEMINIFEROUS TUBULES. They surround and nourish the developing male germ cells and secrete ANDROGEN-BINDING PROTEIN and hormones such as ANTI-MULLERIAN HORMONE. The tight junctions of Sertoli cells with the SPERMATOGONIA and SPERMATOCYTES provide a BLOOD-TESTIS BARRIER.
The epithelium lining the seminiferous tubules composed of primary male germ cells (SPERMATOGONIA) and supporting SERTOLI CELLS. As SPERMATOGENESIS proceeds, the developing germ cells migrate toward the lumen. The adluminal compartment, the inner two thirds of the tubules, contains SPERMATOCYTES and the more advanced germ cells.
The convoluted tubules in the TESTIS where sperm are produced (SPERMATOGENESIS) and conveyed to the RETE TESTIS. Spermatogenic tubules are composed of developing germ cells and the supporting SERTOLI CELLS.
The cap-like structure covering the anterior portion of SPERM HEAD. Acrosome, derived from LYSOSOMES, is a membrane-bound organelle that contains the required hydrolytic and proteolytic enzymes necessary for sperm penetration of the egg in FERTILIZATION.
A group of simple proteins that yield basic amino acids on hydrolysis and that occur combined with nucleic acid in the sperm of fish. Protamines contain very few kinds of amino acids. Protamine sulfate combines with heparin to form a stable inactive complex; it is used to neutralize the anticoagulant action of heparin in the treatment of heparin overdose. (From Merck Index, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p692)
The posterior filiform portion of the spermatozoon (SPERMATOZOA) that provides sperm motility.
The inability of the male to effect FERTILIZATION of an OVUM after a specified period of unprotected intercourse. Male sterility is permanent infertility.
A condition of suboptimal concentration of SPERMATOZOA in the ejaculated SEMEN to ensure successful FERTILIZATION of an OVUM. In humans, oligospermia is defined as a sperm count below 20 million per milliliter semen.
Euploid male germ cells of an early stage of SPERMATOGENESIS, derived from prespermatogonia. With the onset of puberty, spermatogonia at the basement membrane of the seminiferous tubule proliferate by mitotic then meiotic divisions and give rise to the haploid SPERMATOCYTES.
The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.
The convoluted cordlike structure attached to the posterior of the TESTIS. Epididymis consists of the head (caput), the body (corpus), and the tail (cauda). A network of ducts leaving the testis joins into a common epididymal tubule proper which provides the transport, storage, and maturation of SPERMATOZOA.
A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.
The chromosomal constitution of cells, in which each type of CHROMOSOME is represented once. Symbol: N.
A count of SPERM in the ejaculum, expressed as number per milliliter.
The capacity to conceive or to induce conception. It may refer to either the male or female.
The reproductive cells in multicellular organisms at various stages during GAMETOGENESIS.
The maturing process of SPERMATOZOA after leaving the testicular SEMINIFEROUS TUBULES. Maturation in SPERM MOTILITY and FERTILITY takes place in the EPIDIDYMIS as the sperm migrate from caput epididymis to cauda epididymis.
The stage in the first meiotic prophase, following ZYGOTENE STAGE, when CROSSING OVER between homologous CHROMOSOMES begins.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Genes that are located on the Y CHROMOSOME.
An assisted fertilization technique consisting of the microinjection of a single viable sperm into an extracted ovum. It is used principally to overcome low sperm count, low sperm motility, inability of sperm to penetrate the egg, or other conditions related to male infertility (INFERTILITY, MALE).
A specialized barrier, in the TESTIS, between the interstitial BLOOD compartment and the adluminal compartment of the SEMINIFEROUS TUBULES. The barrier is formed by layers of cells from the VASCULAR ENDOTHELIUM of the capillary BLOOD VESSELS, to the SEMINIFEROUS EPITHELIUM of the seminiferous tubules. TIGHT JUNCTIONS form between adjacent SERTOLI CELLS, as well as between the ENDOTHELIAL CELLS.
The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.
Steroid-producing cells in the interstitial tissue of the TESTIS. They are under the regulation of PITUITARY HORMONES; LUTEINIZING HORMONE; or interstitial cell-stimulating hormone. TESTOSTERONE is the major androgen (ANDROGENS) produced.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Agents, either mechanical or chemical, which destroy spermatozoa in the male genitalia and block spermatogenesis.
Movement characteristics of SPERMATOZOA in a fresh specimen. It is measured as the percentage of sperms that are moving, and as the percentage of sperms with productive flagellar motion such as rapid, linear, and forward progression.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Methods pertaining to the generation of new individuals, including techniques used in selective BREEDING, cloning (CLONING, ORGANISM), and assisted reproduction (REPRODUCTIVE TECHNIQUES, ASSISTED).
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
A condition of having no sperm present in the ejaculate (SEMEN).
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)

Identification of a nuclear localization signal in activin/inhibin betaA subunit; intranuclear betaA in rat spermatogenic cells. (1/1081)

Activin is a dimeric glycoprotein hormone that was initially characterized by its ability to stimulate pituitary FSH secretion and was subsequently recognized as a growth factor with diverse biological functions in a large variety of tissues. In the testis, activin has been implicated in the auto/paracrine regulation of spermatogenesis through its cognate cell membrane receptors on Sertoli and germ cells. In this study we provide evidence for intranuclear activin/inhibin betaA subunit and show its distribution in the rat seminiferous epithelium. We have shown by transient expression in HeLa cells of beta-galactosidase fusion proteins that the betaA subunit precursor contains a functional nuclear localization signal within the lysine-rich sequence corresponding to amino acids 231-244. In all stages of the rat seminiferous epithelial cycle, an intense immunohistochemical staining of nuclear betaA was demonstrated in intermediate or type B spermatogonia or primary spermatocytes in their initial stages of the first meiotic prophase, as well as in pachytene spermatocytes and elongating spermatids primarily in stages IX-XII. In some pachytene spermatocytes, the pattern of betaA immunoreactivity was consistent with the characteristic distribution of pachytene chromosomes. In the nuclei of round spermatids, betaA immunoreactivity was less intense, and in late spermatids it was localized in the residual cytoplasm, suggesting disposal of betaA before spermatozoal maturation. Immunoblot analysis of a protein extract from isolated testicular nuclei revealed a nuclear betaA species with a molecular mass of approximately 24 kDa, which is more than 1.5 times that of the mature activin betaA subunit present in activin dimers. These results suggest that activin/inhibin betaA may elicit its biological functions through two parallel signal transduction pathways, one involving the dimeric molecule and cell surface receptors and the other an alternately processed betaA sequence acting directly within the nucleus. According to our immunohistochemical data, betaA may play a significant role in the regulation of nuclear functions during meiosis and spermiogenesis.  (+info)

The degenerative fate of germ cells not conforming to stage in the pubertal golden hamster testis. (2/1081)

In the golden hamster (Mesocricetus auratus), pubertal establishment of spermatogenesis includes a defined period (d 26-30 of life) during which elongation of spermatids is selectively arrested. The resulting appearance of germ cell associations not conforming to stage and the phenomenon of desynchronisation-related germ cell degeneration are analysed both quantitatively and qualitatively by means of light and 'retrospective' electron microscopy. From d 26 onwards, the portion of tubules containing non-stage conforming germ cell associations gradually increases up to 37.5% of sectioned tubules on d 32. Concomitantly, the degree of desynchronisation rises to a maturational gap between spermatids and associated younger germ cells of 7 stages of the seminiferous epithelium cycle, i.e. of fully half a cycle. Beyond d 32, the frequency of desynchronised tubule segments decreases again. Some of the arrested round spermatids and, eventually, all belatedly elongating spermatids degenerate and are lost from the epithelium. Thus a regular maturation of advanced spermatids does not succeed under non-stage conforming conditions. Possibly it is not the desynchronisation between the associated germ cell generations and the spermatids by itself that impedes normal further development of the latter cells. Instead this may be due to the maturational delay of the stage-aberrant cells by several stages compared to the seminiferous epithelium as a whole and, especially, in relation to the stage-conditioned functional state of the neighbouring Sertoli cells.  (+info)

Genetic analysis of viable Hsp90 alleles reveals a critical role in Drosophila spermatogenesis. (3/1081)

The Hsp90 chaperone protein maintains the activities of a remarkable variety of signal transducers, but its most critical functions in the context of the whole organism are unknown. Point mutations of Hsp83 (the Drosophila Hsp90 gene) obtained in two different screens are lethal as homozygotes. We report that eight transheterozygous mutant combinations produce viable adults. All exhibit the same developmental defects: sterile males and sterile or weakly fertile females. We also report that scratch, a previously identified male-sterile mutation, is an allele of Hsp82 with a P-element insertion in the intron that reduces expression. Thus, it is a simple reduction in Hsp90 function, rather than possible altered functions in the point mutants, that leads to male sterility. As shown by light and electron microscopy, all stages of spermatogenesis involving microtubule function are affected, from early mitotic divisions to later stages of sperm maturation, individualization, and motility. Aberrant microtubules are prominent in yeast cells carrying mutations in HSP82 (the yeast Hsp90 gene), confirming that Hsp90 function is connected to microtubule dynamics and that this connection is highly conserved. A small fraction of Hsp90 copurifies with taxol-stabilized microtubule proteins in Drosophila embryo extracts, but Hsp90 does not remain associated with microtubules through repeated temperature-induced assembly and disassembly reactions. If the spermatogenesis phenotypes are due to defects in microtubule dynamics, we suggest these are indirect, reflecting a role for Hsp90 in maintaining critical signal transduction pathways and microtubule effectors, rather than a direct role in the assembly and disassembly of microtubules themselves.  (+info)

Fertilization, embryonic development, and offspring from mouse eggs injected with round spermatids combined with Ca2+ oscillation-inducing sperm factor. (4/1081)

Round spermatids, precursor male gametes, are known to possess the potential to achieve fertilization and embryonic development when injected into eggs. However, injection of spermatids alone seldom activates eggs in the mouse, as spermatids by themselves cannot induce an increase in intracellular Ca2+, a prerequisite for egg activation. We injected a mouse round spermatid into an egg simultaneously with partially purified sperm factor from differentiated hamster spermatozoa. The combined injection produced repetitive Ca2+ increases (Ca2+ oscillations) lasting for at least 4 h as observed at fertilization, and induced activation in 92% of eggs. This method provided 75% fertilization success associated with male and female pronucleus formation and development to 2-cell embryos, while only 7% of eggs were fertilized by injection of a spermatid alone. Of the 2-cell embryos, approximately 50% developed to blastocysts during 5 days of culture in vitro, while no blastocysts were obtained following injection of sperm factor alone. Furthermore, the 2-cell embryos, that were created by spermatids and sperm factor and transplanted into foster mothers, developed into normal offspring, although the percentage was only 22%. All infants grew into healthy adults carrying normal chromosomes. The sperm factor served as a complementary factor for successful fertilization by round spermatid injection.  (+info)

Histone ubiquitination and chromatin remodeling in mouse spermatogenesis. (5/1081)

Male infertility in HR6B knockout mice is associated with impairment of spermatogenesis. The HR6B gene is a mammalian, autosomal homolog of the Saccharomyces cerevisiae gene Rad6 encoding a ubiquitin-conjugating enzyme. In addition, X-chromosomal HR6A has been identified, in human and mouse. RAD6 in yeast is required for a variety of cellular functions, including sporulation, DNA repair, and mutagenesis. Since RAD6 and its mammalian homologs can ubiquitinate histones in vitro, we have investigated the pattern of histone ubiquitination in mouse testis. By immunoblot and immunohistochemical analysis of wild-type mouse testis, a high amount of ubiquitinated H2A (uH2A) was detected in pachytene spermatocytes. This signal became undetectable in round spermatids, but then increased again during a relatively short developmental period, in elongating spermatids. No other ubiquitinated histones were observed. In the HR6B knockout mice, we failed to detect an overt defect in the overall pattern of histone ubiquitination. For somatic cell types, it has been shown that histone ubiquitination is associated with destabilization of nucleosomes, in relation to active gene transcription. Unexpectedly, the most intense uH2A signal in pachytene spermatocytes was detected in the sex body, an inactive nuclear structure that contains the heterochromatic X and Y chromosomes. The postmeiotic uH2A immunoexpression in elongating spermatids indicates that nucleosome destabilization induced by histone ubiquitination may play a facilitating role during histone-to-protamine replacement.  (+info)

A novel quantitative morphometry of germ cells for the histopathological evaluation of rat testicular toxicity. (6/1081)

A view that 14 stages of rat spermatogenic cycle could be arranged into 4 groups, viz., conventional stages I-VI, VII-VIII, IX-XI and XII-XIV, according to the features of elongated spermatids was previously presented. A novel morphometry of seminiferous epithelia based on these 4 groups was also proposed. In the present study, utility of the proposed morphometry in the histopathological evaluations of testicular toxicities was monitored in comparison with the conventional one. After administrating adriamycin, ethylene glycol monomethyl ether or 1,3-dinitrobenzene to rats, the viability of their germ cells was estimated by the proposed morphometry and the conventional one employed stages II-III, V, VII, X and XII. In every case, the evaluating results of the proposed morphometry were similar to those of the conventional one. Thus, it was verified that the proposed morphometry was identical with the conventional one in respect of reliable detection of the testicular toxicities. In addition, in situ terminal dUTP nick end labeling indicated that death of spermatogonia, pachytene spermatocytes or round spermatids induced by the above 3 toxic compounds was exclusively apoptotic death. In conclusion, the proposed morphometry would be useful as a practical tool in the evaluation of testicular toxicities.  (+info)

Sperm abnormalities and histopathological changes in the testes in Crj:CD(SD)IGS rats. (7/1081)

In this study, morphological examination and computer-assisted sperm analysis (CASA) of epididymal spermatozoa in non-treated Crj:CD(SD)IGS rats were performed, and the relationship between the data obtained and the retention of step 19 spermatids in Stage IX to XI seminiferous tubules was examined. Retention of step 19 spermatids in Stage IX to XI seminiferous tubules was observed in all 50 untreated males, and the incidence ranged from 3.3% to 100%. Eighteen animals showed a high incidence of retention (74.7 +/- 14.2%, HIR for short), and the others showed a low incidence (24.9 +/- 11.0%, LIR for short). Although the incidence of retention in Stage X and XI seminiferous tubules was very low in LIR males, it was high in HIR males (1.8 +/- 3.0% vs 58.6 +/- 23.2%). Morphological abnormalities of sperms in the caudal region of the epididymis, mainly amorphous head and no head, were more frequently observed in HIR males than in LIR males (36.2 +/- 28.5% vs 1.8 +/- 1.2%). Sperm analysis also revealed some differences between HIR and LIR males: sperm motility in HIR males was severely lower than that in LIR males, and sperm velocity, beat/cross frequency and amplitude of lateral head displacement in HIR males were lower than the corresponding values in LIR males. In summation, retention of step 19 spermatids frequently occurred in the non-treated Crj:CD(SD)IGS males, and a relationship between the retention of these spermatids and sperm abnormalities, such as morphologically abnormal sperms, low motility and other items revealed by sperm analysis (CASA), was suggested.  (+info)

Truncated RanGAP encoded by the Segregation Distorter locus of Drosophila. (8/1081)

Segregation Distorter (SD) in Drosophila melanogaster is a naturally occurring meiotic drive system in which the SD chromosome is transmitted from SD/SD+ males in vast excess over its homolog owing to the induced dysfunction of SD+-bearing spermatids. The Sd locus is the key distorting gene responsible for this phenotype. A genomic fragment from the Sd region conferred full distorting activity when introduced into the appropriate genetic background by germline transformation. The only functional product encoded by this fragment is a truncated version of the RanGAP nuclear transport protein. These results demonstrate that this mutant RanGAP is the functional Sd product.  (+info)

Spermatids are immature sperm cells that are produced during the process of spermatogenesis in the male testes. They are the product of the final stage of meiosis, where a diploid spermatocyte divides into four haploid spermatids. Each spermatid then undergoes a series of changes, including the development of a tail for motility and the condensation of its nucleus to form a head containing the genetic material. Once this process is complete, the spermatids are considered mature spermatozoa and are capable of fertilizing an egg.

Spermatogenesis is the process by which sperm cells, or spermatozoa, are produced in male organisms. It occurs in the seminiferous tubules of the testes and involves several stages:

1. Spermatocytogenesis: This is the initial stage where diploid spermatogonial stem cells divide mitotically to produce more spermatogonia, some of which will differentiate into primary spermatocytes.
2. Meiosis: The primary spermatocytes undergo meiotic division to form haploid secondary spermatocytes, which then divide again to form haploid spermatids. This process results in the reduction of chromosome number from 46 (diploid) to 23 (haploid).
3. Spermiogenesis: The spermatids differentiate into spermatozoa, undergoing morphological changes such as the formation of a head and tail. During this stage, most of the cytoplasm is discarded, resulting in highly compacted and streamlined sperm cells.
4. Spermation: The final stage where mature sperm are released from the seminiferous tubules into the epididymis for further maturation and storage.

The entire process takes approximately 72-74 days in humans, with continuous production throughout adulthood.

The testis, also known as the testicle, is a male reproductive organ that is part of the endocrine system. It is located in the scrotum, outside of the abdominal cavity. The main function of the testis is to produce sperm and testosterone, the primary male sex hormone.

The testis is composed of many tiny tubules called seminiferous tubules, where sperm are produced. These tubules are surrounded by a network of blood vessels, nerves, and supportive tissues. The sperm then travel through a series of ducts to the epididymis, where they mature and become capable of fertilization.

Testosterone is produced in the Leydig cells, which are located in the interstitial tissue between the seminiferous tubules. Testosterone plays a crucial role in the development and maintenance of male secondary sexual characteristics, such as facial hair, deep voice, and muscle mass. It also supports sperm production and sexual function.

Abnormalities in testicular function can lead to infertility, hormonal imbalances, and other health problems. Regular self-examinations and medical check-ups are recommended for early detection and treatment of any potential issues.

Spermatocytes are a type of cell that is involved in the process of spermatogenesis, which is the formation of sperm in the testes. Specifically, spermatocytes are the cells that undergo meiosis, a special type of cell division that results in the production of four haploid daughter cells, each containing half the number of chromosomes as the parent cell.

There are two types of spermatocytes: primary and secondary. Primary spermatocytes are diploid cells that contain 46 chromosomes (23 pairs). During meiosis I, these cells undergo a process called crossing over, in which genetic material is exchanged between homologous chromosomes. After crossing over, the primary spermatocytes divide into two secondary spermatocytes, each containing 23 chromosomes (but still with 23 pairs).

Secondary spermatocytes then undergo meiosis II, which results in the formation of four haploid spermatids. Each spermatid contains 23 single chromosomes and will eventually develop into a mature sperm cell through a process called spermiogenesis.

It's worth noting that spermatocytes are only found in males, as they are specific to the male reproductive system.

Spermatozoa are the male reproductive cells, or gametes, that are produced in the testes. They are microscopic, flagellated (tail-equipped) cells that are highly specialized for fertilization. A spermatozoon consists of a head, neck, and tail. The head contains the genetic material within the nucleus, covered by a cap-like structure called the acrosome which contains enzymes to help the sperm penetrate the female's egg (ovum). The long, thin tail propels the sperm forward through fluid, such as semen, enabling its journey towards the egg for fertilization.

Sertoli cells, also known as sustentacular cells or nurse cells, are specialized cells in the seminiferous tubules of the testis in mammals. They play a crucial role in supporting and nurturing the development of sperm cells (spermatogenesis). Sertoli cells create a microenvironment within the seminiferous tubules that facilitates the differentiation, maturation, and survival of germ cells.

These cells have several essential functions:

1. Blood-testis barrier formation: Sertoli cells form tight junctions with each other, creating a physical barrier called the blood-testis barrier, which separates the seminiferous tubules into basal and adluminal compartments. This barrier protects the developing sperm cells from the immune system and provides an isolated environment for their maturation.
2. Nutrition and support: Sertoli cells provide essential nutrients and growth factors to germ cells, ensuring their proper development and survival. They also engulf and digest residual bodies, which are byproducts of spermatid differentiation.
3. Phagocytosis: Sertoli cells have phagocytic properties, allowing them to remove debris and dead cells within the seminiferous tubules.
4. Hormone metabolism: Sertoli cells express receptors for various hormones, such as follicle-stimulating hormone (FSH), testosterone, and estradiol. They play a role in regulating hormonal signaling within the testis by metabolizing these hormones or producing inhibins, which modulate FSH secretion from the pituitary gland.
5. Regulation of spermatogenesis: Sertoli cells produce and secrete various proteins and growth factors that influence germ cell development and proliferation. They also control the release of mature sperm cells into the epididymis through a process called spermiation.

The seminiferous epithelium is a specialized type of epithelial tissue that lines the seminiferous tubules within the testes. It is composed of various cell types, including germ cells in different stages of development (spermatogonia, primary and secondary spermatocytes, spermatids) and supportive cells called Sertoli cells.

The primary function of the seminiferous epithelium is to support sperm production (spermatogenesis). The Sertoli cells provide structural support and nourishment to the developing germ cells, helping them to differentiate into mature spermatozoa (sperm). This process involves a series of complex cellular events, including mitosis, meiosis, and spermiogenesis.

In addition to its role in sperm production, the seminiferous epithelium also plays a crucial part in maintaining the blood-testis barrier, which separates the testicular environment from the systemic circulation. This barrier helps protect developing germ cells from potential immune attacks and maintains an optimal microenvironment for spermatogenesis.

Seminiferous tubules are the long, convoluted tubes within the testicles that are responsible for producing sperm in males. They are lined with specialized epithelial cells called Sertoli cells, which provide structural support and nourishment to developing sperm cells. The seminiferous tubules also contain germ cells, which divide and differentiate into spermatozoa (sperm) through the process of spermatogenesis.

The seminiferous tubules are surrounded by a thin layer of smooth muscle called the tunica albuginea, which helps to maintain the structure and integrity of the testicle. The tubules are connected to the rete testis, a network of channels that transport sperm to the epididymis for further maturation and storage before ejaculation.

Damage or dysfunction of the seminiferous tubules can lead to male infertility, as well as other reproductive health issues.

The acrosome is a specialized structure located on the anterior part of the sperm head in many species of animals, including humans. It contains enzymes that help the sperm penetrate the outer covering of the egg (zona pellucida) during fertilization. The acrosome reaction is the process by which the acrosome releases its enzymes, allowing the sperm to digest a path through the zona pellucida and reach the egg plasma membrane for fusion and fertilization.

The acrosome is formed during spermatogenesis, the process of sperm production in the testis, from the Golgi apparatus, a cellular organelle involved in protein trafficking and modification. The acrosome contains hydrolytic enzymes such as hyaluronidase, acrosin, and proteases that are activated during the acrosome reaction to facilitate sperm-egg fusion.

Abnormalities in acrosome formation or function can lead to infertility in males.

Protamines are small, arginine-rich proteins that are found in the sperm cells of many organisms. They play a crucial role in the process of sperm maturation, also known as spermiogenesis. During this process, the DNA in the sperm cell is tightly packed and compacted by the protamines, which helps to protect the genetic material during its journey to fertilize an egg.

Protamines are typically composed of around 50-100 amino acids and have a high proportion of positively charged arginine residues, which allow them to interact strongly with the negatively charged DNA molecule. This interaction results in the formation of highly condensed chromatin structures that are resistant to enzymatic digestion and other forms of damage.

In addition to their role in sperm maturation, protamines have also been studied for their potential use in drug delivery and gene therapy applications. Their ability to bind strongly to DNA makes them attractive candidates for delivering drugs or genetic material directly to the nucleus of a cell. However, more research is needed to fully understand the potential benefits and risks associated with these applications.

The "sperm tail" is also known as the flagellum, which is a whip-like structure that enables the sperm to move or swim through fluid. The human sperm tail is made up of nine microtubule doublets and a central pair of microtubules, which are surrounded by a mitochondrial sheath that provides energy for its movement. This complex structure allows the sperm to navigate through the female reproductive tract in order to reach and fertilize an egg.

Male infertility is a condition characterized by the inability to cause pregnancy in a fertile female. It is typically defined as the failure to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse.

The causes of male infertility can be varied and include issues with sperm production, such as low sperm count or poor sperm quality, problems with sperm delivery, such as obstructions in the reproductive tract, or hormonal imbalances that affect sperm production. Other factors that may contribute to male infertility include genetic disorders, environmental exposures, lifestyle choices, and certain medical conditions or treatments.

It is important to note that male infertility can often be treated or managed with medical interventions, such as medication, surgery, or assisted reproductive technologies (ART). A healthcare provider can help diagnose the underlying cause of male infertility and recommend appropriate treatment options.

Oligospermia is a medical term used to describe a condition in which the semen contains a lower than normal number of sperm. Generally, a sperm count of less than 15 million sperm per milliliter (ml) of semen is considered to be below the normal range.

Oligospermia can make it more difficult for a couple to conceive naturally and may require medical intervention such as intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF). The condition can result from various factors, including hormonal imbalances, genetic abnormalities, varicocele, environmental factors, and certain medications.

It's important to note that oligospermia is not the same as azoospermia, which is a condition where there is no sperm present in the semen at all.

Spermatogonia are a type of diploid germ cells found in the seminiferous tubules of the testis. They are the stem cells responsible for sperm production (spermatogenesis) in males. There are two types of spermatogonia: A-dark (Ad) and A-pale (Ap). The Ad spermatogonia function as reserve stem cells, while the Ap spermatogonia serve as the progenitor cells that divide to produce type B spermatogonia. Type B spermatogonia then differentiate into primary spermatocytes, which undergo meiosis to form haploid spermatozoa.

A sperm head is the anterior (front) part of a spermatozoon, which contains the genetic material (DNA). It is covered by a protein layer called the acrosome, which plays a crucial role in fertilization. The sperm head is followed by the midpiece and the tail, which provide mobility to the sperm for its journey towards the egg.

The epididymis is a tightly coiled tube located on the upper and posterior portion of the testicle that serves as the site for sperm maturation and storage. It is an essential component of the male reproductive system. The epididymis can be divided into three parts: the head (where newly produced sperm enter from the testicle), the body, and the tail (where mature sperm exit and are stored). Any abnormalities or inflammation in the epididymis may lead to discomfort, pain, or infertility.

Meiosis is a type of cell division that results in the formation of four daughter cells, each with half the number of chromosomes as the parent cell. It is a key process in sexual reproduction, where it generates gametes or sex cells (sperm and eggs).

The process of meiosis involves one round of DNA replication followed by two successive nuclear divisions, meiosis I and meiosis II. In meiosis I, homologous chromosomes pair, form chiasma and exchange genetic material through crossing over, then separate from each other. In meiosis II, sister chromatids separate, leading to the formation of four haploid cells. This process ensures genetic diversity in offspring by shuffling and recombining genetic information during the formation of gametes.

Haploidy is a term used in genetics to describe the condition of having half the normal number of chromosomes in a cell or an organism. In humans, for example, a haploid cell contains 23 chromosomes, whereas a diploid cell has 46 chromosomes.

Haploid cells are typically produced through a process called meiosis, which is a type of cell division that occurs in the reproductive organs of sexually reproducing organisms. During meiosis, a diploid cell undergoes two rounds of division to produce four haploid cells, each containing only one set of chromosomes.

In humans, haploid cells are found in the sperm and egg cells, which fuse together during fertilization to create a diploid zygote with 46 chromosomes. Haploidy is important for maintaining the correct number of chromosomes in future generations and preventing genetic abnormalities that can result from having too many or too few chromosomes.

Sperm count, also known as sperm concentration, is the number of sperm present in a given volume of semen. The World Health Organization (WHO) previously defined a normal sperm count as at least 20 million sperm per milliliter of semen. However, more recent studies suggest that fertility may be affected even when sperm counts are slightly lower than this threshold. It's important to note that sperm count is just one factor among many that can influence male fertility. Other factors, such as sperm motility (the ability of sperm to move properly) and morphology (the shape of the sperm), also play crucial roles in successful conception.

Fertility is the natural ability to conceive or to cause conception of offspring. In humans, it is the capacity of a woman and a man to reproduce through sexual reproduction. For women, fertility usually takes place during their reproductive years, which is from adolescence until menopause. A woman's fertility depends on various factors including her age, overall health, and the health of her reproductive system.

For men, fertility can be affected by a variety of factors such as age, genetics, general health, sexual function, and environmental factors that may affect sperm production or quality. Factors that can negatively impact male fertility include exposure to certain chemicals, radiation, smoking, alcohol consumption, drug use, and sexually transmitted infections (STIs).

Infertility is a common medical condition affecting about 10-15% of couples trying to conceive. Infertility can be primary or secondary. Primary infertility refers to the inability to conceive after one year of unprotected sexual intercourse, while secondary infertility refers to the inability to conceive following a previous pregnancy.

Infertility can be treated with various medical and surgical interventions depending on the underlying cause. These may include medications to stimulate ovulation, intrauterine insemination (IUI), in vitro fertilization (IVF), or surgery to correct anatomical abnormalities.

Germ cells are the reproductive cells, also known as sex cells, that combine to form offspring in sexual reproduction. In females, germ cells are called ova or egg cells, and in males, they are called spermatozoa or sperm cells. These cells are unique because they carry half the genetic material necessary for creating new life. They are produced through a process called meiosis, which reduces their chromosome number by half, ensuring that when two germ cells combine during fertilization, the normal diploid number of chromosomes is restored.

Sperm maturation is the process by which spermatids, immature sperm cells produced in meiosis, transform into fully developed spermatozoa capable of fertilization. This complex process occurs in the seminiferous tubules of the testes and includes several stages:

1. **Golfi formation:** The first step involves the spermatids reorganizing their cytoplasm and forming a cap-like structure called the acrosome, which contains enzymes that help the sperm penetrate the egg's outer layers during fertilization.
2. **Flagellum development:** The spermatid also develops a tail (flagellum), enabling it to move independently. This is achieved through the assembly of microtubules and other associated proteins.
3. **Nuclear condensation and elongation:** The sperm's DNA undergoes significant compaction, making the nucleus smaller and more compact. Concurrently, the nucleus elongates and aligns with the flagellum.
4. **Mitochondrial positioning:** Mitochondria, which provide energy for sperm motility, migrate to the midpiece of the sperm, close to the base of the flagellum.
5. **Chromatin packaging:** Histones, proteins that help package DNA in non-sperm cells, are replaced by transition proteins and then protamines, which further compact and protect the sperm's DNA.
6. **Sperm release (spermiation):** The mature sperm is finally released from the supporting Sertoli cells into the lumen of the seminiferous tubule, where it mixes with fluid secreted by the testicular tissue to form seminal plasma.

This entire process takes approximately 64 days in humans.

The pachytene stage is a phase in the meiotic division of sex cells (gametes) such as sperm and egg cells, specifically during prophase I. In this stage, homologous chromosomes are fully paired and have formed tetrads, or four-stranded structures called chiasma where genetic recombination occurs between the non-sister chromatids of each homologous chromosome. This is a crucial step in the creation of genetic diversity in the offspring. The pachytene stage is characterized by the presence of a protein matrix called the synaptonemal complex, which holds the homologous chromosomes together and facilitates crossing over.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

Y-linked genes are a type of sex-limited gene that is located on the Y chromosome. These genes are only present in males because they are passed from father to son through the paternal Y chromosome during reproduction. They are not paired with any corresponding genes on the X chromosome, and therefore, they do not have a counterpart to complement their function.

Y-linked genes play an essential role in sex determination and male development. For example, the SRY gene, which is located on the Y chromosome, encodes a protein that triggers testis development during embryonic development. Other Y-linked genes are involved in spermatogenesis, the process of producing sperm cells.

Since Y-linked genes are not present in females, they do not have any direct impact on female traits or characteristics. However, mutations in Y-linked genes can cause various genetic disorders that affect male fertility and development, such as Klinefelter syndrome, XYY syndrome, and other sex chromosome aneuploidies.

Intracytoplasmic Sperm Injection (ICSI) is a specialized form of assisted reproductive technology (ART), specifically used in the context of in vitro fertilization (IVF). It involves the direct injection of a single sperm into the cytoplasm of a mature egg (oocyte) to facilitate fertilization. This technique is often used when there are issues with male infertility, such as low sperm count or poor sperm motility, to increase the chances of successful fertilization. The resulting embryos can then be transferred to the uterus in hopes of achieving a pregnancy.

The Blood-Testis Barrier (BTB) is a unique structural and functional feature of the seminiferous epithelium in the testes, which forms a tight junction between adjacent Sertoli cells in the semi-niferous tubules. This barrier selectively restricts the passage of molecules, including potentially harmful substances and immune cells, from the systemic circulation into the adluminal compartment of the seminiferous epithelium where spermatogenesis occurs. This helps to maintain a immunologically privileged microenvironment that is essential for the survival and maturation of developing sperm cells, preventing an immune response against them. The BTB also regulates the movement of molecules required for spermatogenesis, such as nutrients, hormones, and signaling molecules, from the basal compartment to the adluminal compartment.

Microinjection is a medical technique that involves the use of a fine, precise needle to inject small amounts of liquid or chemicals into microscopic structures, cells, or tissues. This procedure is often used in research settings to introduce specific substances into individual cells for study purposes, such as introducing DNA or RNA into cell nuclei to manipulate gene expression.

In clinical settings, microinjections may be used in various medical and cosmetic procedures, including:

1. Intracytoplasmic Sperm Injection (ICSI): A type of assisted reproductive technology where a single sperm is injected directly into an egg to increase the chances of fertilization during in vitro fertilization (IVF) treatments.
2. Botulinum Toxin Injections: Microinjections of botulinum toxin (Botox, Dysport, or Xeomin) are used for cosmetic purposes to reduce wrinkles and fine lines by temporarily paralyzing the muscles responsible for their formation. They can also be used medically to treat various neuromuscular disorders, such as migraines, muscle spasticity, and excessive sweating (hyperhidrosis).
3. Drug Delivery: Microinjections may be used to deliver drugs directly into specific tissues or organs, bypassing the systemic circulation and potentially reducing side effects. This technique can be particularly useful in treating localized pain, delivering growth factors for tissue regeneration, or administering chemotherapy agents directly into tumors.
4. Gene Therapy: Microinjections of genetic material (DNA or RNA) can be used to introduce therapeutic genes into cells to treat various genetic disorders or diseases, such as cystic fibrosis, hemophilia, or cancer.

Overall, microinjection is a highly specialized and precise technique that allows for the targeted delivery of substances into small structures, cells, or tissues, with potential applications in research, medical diagnostics, and therapeutic interventions.

Leydig cells, also known as interstitial cells of Leydig or interstitial cell-stroma, are cells in the testes that produce and release testosterone and other androgens into the bloodstream. They are located in the seminiferous tubules of the testis, near the blood vessels, and are named after Franz Leydig, the German physiologist who discovered them in 1850.

Leydig cells contain cholesterol esters, which serve as precursors for the synthesis of testosterone. They respond to luteinizing hormone (LH) released by the anterior pituitary gland, which stimulates the production and release of testosterone. Testosterone is essential for the development and maintenance of male secondary sexual characteristics, such as facial hair, deep voice, and muscle mass. It also plays a role in sperm production and bone density.

In addition to their endocrine function, Leydig cells have been shown to have non-hormonal functions, including phagocytosis, antigen presentation, and immune regulation. However, these functions are not as well understood as their hormonal roles.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Antispermatogenic agents are substances or drugs that inhibit or prevent the production of sperm in the testes. These agents can work by various mechanisms, such as interfering with the formation and maturation of sperm cells, damaging sperm DNA, or suppressing the hormones responsible for sperm production.

Examples of antispermatogenic agents include chemotherapy drugs, radiation therapy, and certain medications used to treat prostate cancer or other conditions. Prolonged use of these agents can lead to infertility, so they are often used with caution and only when necessary. It is important to note that the use of antispermatogenic agents should be under the guidance and supervision of a medical professional.

Sperm motility is the ability of sperm to move actively and effectively through the female reproductive tract towards the egg for fertilization. It is typically measured as the percentage of moving sperm in a sample, and their progressiveness or velocity. Normal human sperm motility is generally defined as forward progression of at least 25 micrometers per second, with at least 50% of sperm showing progressive motility. Reduced sperm motility, also known as asthenozoospermia, can negatively impact fertility and reproductive outcomes.

The cell nucleus is a membrane-bound organelle found in the eukaryotic cells (cells with a true nucleus). It contains most of the cell's genetic material, organized as DNA molecules in complex with proteins, RNA molecules, and histones to form chromosomes.

The primary function of the cell nucleus is to regulate and control the activities of the cell, including growth, metabolism, protein synthesis, and reproduction. It also plays a crucial role in the process of mitosis (cell division) by separating and protecting the genetic material during this process. The nuclear membrane, or nuclear envelope, surrounding the nucleus is composed of two lipid bilayers with numerous pores that allow for the selective transport of molecules between the nucleoplasm (nucleus interior) and the cytoplasm (cell exterior).

The cell nucleus is a vital structure in eukaryotic cells, and its dysfunction can lead to various diseases, including cancer and genetic disorders.

Reproductive techniques refer to various methods and procedures used to assist individuals or couples in achieving pregnancy, carrying a pregnancy to term, or preserving fertility. These techniques can be broadly categorized into assisted reproductive technology (ART) and fertility preservation.

Assisted reproductive technology (ART) includes procedures such as:

1. In vitro fertilization (IVF): A process where an egg is fertilized by sperm outside the body in a laboratory dish, and then the resulting embryo is transferred to a woman's uterus.
2. Intracytoplasmic sperm injection (ICSI): A procedure where a single sperm is directly injected into an egg to facilitate fertilization.
3. Embryo culture and cryopreservation: The process of growing embryos in a laboratory for a few days before freezing them for later use.
4. Donor gametes: Using eggs, sperm, or embryos from a known or anonymous donor to achieve pregnancy.
5. Gestational surrogacy: A method where a woman carries and gives birth to a baby for another individual or couple who cannot carry a pregnancy themselves.

Fertility preservation techniques include:

1. Sperm banking: The process of freezing and storing sperm for future use in artificial reproduction.
2. Egg (oocyte) freezing: A procedure where a woman's eggs are extracted, frozen, and stored for later use in fertility treatments.
3. Embryo freezing: The cryopreservation of embryos created through IVF for future use.
4. Ovarian tissue cryopreservation: The freezing and storage of ovarian tissue to restore fertility after cancer treatment or other conditions that may affect fertility.
5. Testicular tissue cryopreservation: The collection and storage of testicular tissue in prepubertal boys undergoing cancer treatment to preserve their future fertility potential.

Immunohistochemistry (IHC) is a technique used in pathology and laboratory medicine to identify specific proteins or antigens in tissue sections. It combines the principles of immunology and histology to detect the presence and location of these target molecules within cells and tissues. This technique utilizes antibodies that are specific to the protein or antigen of interest, which are then tagged with a detection system such as a chromogen or fluorophore. The stained tissue sections can be examined under a microscope, allowing for the visualization and analysis of the distribution and expression patterns of the target molecule in the context of the tissue architecture. Immunohistochemistry is widely used in diagnostic pathology to help identify various diseases, including cancer, infectious diseases, and immune-mediated disorders.

Azoospermia is a medical condition where there is no measurable level of sperm in the semen. This means that during ejaculation, the seminal fluid does not contain any sperm cells. Azoospermia can be caused by various factors including problems with testicular function, obstruction of the genital tract, or hormonal imbalances. It is an important cause of male infertility and may require further medical evaluation and treatment to determine the underlying cause and explore potential options for fertility.

There are two types of azoospermia: obstructive azoospermia and non-obstructive azoospermia. Obstructive azoospermia is caused by blockages or obstructions in the genital tract that prevent sperm from being released into the semen, while non-obstructive azoospermia is due to problems with sperm production in the testicles.

In some cases, men with azoospermia may still be able to father children through assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI), where a single sperm is injected directly into an egg for fertilization. However, this will depend on the underlying cause of the azoospermia and whether or not there are viable sperm available for extraction.

An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.

... although present in round spermatids, appears to be lost as they develop into elongated spermatids. Scheme showing analogies in ... The spermatid is the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each ... They injected these spermatids into mouse eggs and produced pups. As postmeiotic germ cells develop to mature sperm they ... Spermatid DNA also undergoes packaging, becoming highly condensed. The DNA is packaged firstly with specific nuclear basic ...
The study reported that 90% of seminiferous tubules in men in their 20s and 30s contained spermatids, whereas men in their 40s ... In the study, only 10% of seminiferous tubules from men aged > 80 years contained spermatids. In a random international sample ... and 50s had spermatids in 50% of their seminiferous tubules. ...
... of seminiferous tubules in men in their 20s and 30s contain spermatids, whereas men in their 40s and 50s have spermatids in 50 ... of their seminiferous tubules, and only 10% of seminiferous tubules from men aged > 80 years contain spermatids. In a random ...
1989). Genetically haploid spermatids are phenotypically diploid. Nature 337: 373-376. Kloc, M., S. Bilinski, M. T. Dougherty, ... In addition, the fusome connections ensure haploid spermatids have proteins and RNA made by the other chromosome for "gamete ...
... spermatids. These spermatids then undergo differentiation into mature sperm. In these developing male germ cells, they undergo ...
The spermatocytes divide by meiosis to form spermatids. The post-meiotic spermatids differentiate through spermiogenesis to ...
Round spermatid injection (ROSI) is a technique of assisted reproduction whereby a round spermatid is injected into oocyte ... Moreover, the distinction between living round spermatids, to be used in ROSI, and dead round spermatids, to be discarded, ... Consequently, the distinction between round spermatids and other round cells of similar size, such as leukocytes, is not an ... Tesarik J, Mendoza C, Testart J (August 1995). "Viable embryos from injection of round spermatids into oocytes". The New ...
In step 7 round spermatids, the CB starts decreasing in size, and its degradation proceeds in the course of spermatid ... In elongating spermatids, the CB dissociates into two different structures: a ring around the basis of the flagellum and a ... After meiosis in step 1 round spermatids, these dense bodies aggregate and form one single big granule per cell, which is ... In step 16 elongating spermatids, the characteristic structure of the CB is no longer visible. Given the timing of its ...
Wang, Xiangchuan; Hu, Boyi; Zhao, Zhongying; Tse, Yu Chung (July 2022). "From primordial germ cells to spermatids in ...
This spermatogenesis takes place in cysts which contain spermatids. During this time, there is very little observable secretory ...
Spermatid nuclear transition protein 1 is a protein that in humans is encoded by the TNP1 gene. GRCh38: Ensembl release 89: ... Baskaran R, Rao MR (1991). "Interaction of spermatid-specific protein TP2 with nucleic acids, in vitro. A comparative study ... 2007). "Quantitative assessment of transition proteins 1, 2 spermatid-specific linker histone H1-like protein transcripts in ... 1991). "Nuclear transition protein 1 from ram elongating spermatids. Mass spectrometric characterization, primary structure and ...
Then each spermatocyte gives rise to four spermatids through meiosis. Spermatids are now haploid and undergo differentiation ...
These divide and differentiate into spermatocytes, which undergo meiosis to form spermatids. In the spermatid stage, the sperm ... The spermatocytes then undergo meiosis, reducing their chromosome number by half, which produces spermatids. The spermatids ... They injected these spermatids into mouse eggs and produced pups. Sperm quantity and quality are the main parameters in semen ... In 2016, scientists at Nanjing Medical University claimed they had produced cells resembling mouse spermatids from mouse ...
At this point, spermatids extend their pseudopod and become mobile. This process is calcium-dependent and a normal progression ... In C. elegans spermatids are immobile and during sperm maturation mobility is gained after fusion of membraneous organelles ...
These secondary spermatocytes undergo a second meiotic division to produce immature sperms or spermatids. These spermatids ...
Each secondary spermatocyte will form two spermatids after Meiosis II. Although spermatocytes that divide mitotically and ... Germ cells Gametes Gametocytogenesis Leydig Mitosis Meiosis Sertoli cells Spermatogenesis Spermatogonia Spermatid ... spermatocyte layers and spermatids in rat seminiferous tubules. Another critical discovery was that of the hypothalamic- ... which act as nursing cells where spermatids will go to mature after Meiosis II. LH promotes Leydig cell secretion of ...
In the rat, a protein similar to this gene product is expressed in post-meiotic spermatids, where it associates with structural ... Zhang Y, Oko R, van der Hoorn FA (Nov 2004). "Rat kinesin light chain 3 associates with spermatid mitochondria". Developmental ... "Kinesin light-chain KLC3 expression in testis is restricted to spermatids". Biology of Reproduction. 64 (5): 1320-30. doi: ...
The spermatogenous cells give rise to spermatids via mitotic cell division. In some bryophytes, the antheridium is borne on an ...
Mouse stem cells were grown into cells resembling spermatids in 2016. These spermatids, when injected into mouse eggs, were ... Secondary spermatocytes produced earlier rapidly enter meiosis II and divide to produce haploid spermatids. The brevity of this ... Spermatidogenesis is the creation of spermatids from secondary spermatocytes during spermatogenesis. ...
"Kinesin light-chain KLC3 expression in testis is restricted to spermatids". Biol. Reprod. 64 (5): 1320-30. doi:10.1095/ ...
... each secondary spermatocyte divides into two equal haploid spermatids by Meiosis II. The spermatids are transformed into ... During spermiogenesis, the spermatids begin to form a tail by growing microtubules on one of the centrioles, which turns into ... Spermatid DNA also undergoes packaging, becoming highly condensed. The DNA is packaged firstly with specific nuclear basic ... Each cell division from a spermatogonium to a spermatid is incomplete; the cells remain connected to one another by bridges of ...
The spermatids, which up until now have been mostly radially symmetrical, begin to develop polarity. The head forms at one end ... Spermatid DNA also undergoes packaging, becoming highly condensed. The DNA is first packaged with specific nuclear basic ... At the beginning of the stage, the spermatid is a more or less circular cell containing a nucleus, Golgi apparatus, centriole ... Spermiogenesis is the final stage of spermatogenesis, during which the spermatids develop into mature spermatozoa. ...
Spermatid perinuclear RNA-binding protein is a protein that in humans is encoded by the STRBP gene. GRCh38: Ensembl release 89 ... "Entrez Gene: STRBP spermatid perinuclear RNA binding protein". Schumacher JM, Lee K, Edelhoff S, Braun RE (May 1995). "Spnr, a ... Pires-daSilva A, Nayernia K, Engel W, Torres M, Stoykova A, Chowdhury K, Gruss P (May 2001). "Mice deficient for spermatid ... Schumacher JM, Artzt K, Braun RE (July 1998). "Spermatid perinuclear ribonucleic acid-binding protein binds microtubules in ...
Alternatively, they go on to differentiate into spermatocytes, spermatids and finally spermatozoa. One SSC is the precursor for ...
Baskaran R, Rao MR (Jan 1991). "Interaction of spermatid-specific protein TP2 with nucleic acids, in vitro. A comparative study ... Nelson JE, Krawetz SA (1993). "Linkage of human spermatid-specific basic nuclear protein genes. Definition and evolution of the ... 2007). "Quantitative assessment of transition proteins 1, 2 spermatid-specific linker histone H1-like protein transcripts in ...
... is important role player in spermatid development. The nectin-3-/- male mice were found to have defects in the later ... "Role of cell adhesion molecule nectin-3 in spermatid development". Genes to Cells. 11 (9): 1125-1132. doi:10.1111/j.1365- ...
... creating haploid spermatids. During spermiogenesis, the last stage of spermatogenesis, the haploid spermatids develop into ...
... is located in the cilia of spermatids, retina, and bronchial epithelium cells. Mutations in the TTC8 gene is one of 14 ...
DAZ pushes ESCs in to germ cells with molecular features of being spermatids. DAZL is expressed in humans from early progenitor ...
The two secondary spermatocytes undergo the second meiotic division to form four haploid spermatids. These spermatids ... Spermatogenesis has equivalent meiotic divisions resulting in four equivalent spermatids while oogenic meiosis is asymmetrical ...
... although present in round spermatids, appears to be lost as they develop into elongated spermatids. Scheme showing analogies in ... The spermatid is the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each ... They injected these spermatids into mouse eggs and produced pups. As postmeiotic germ cells develop to mature sperm they ... Spermatid DNA also undergoes packaging, becoming highly condensed. The DNA is packaged firstly with specific nuclear basic ...
View mouse Spem1 Chr11:69711697-69712991 with: phenotypes, sequences, polymorphisms, proteins, references, function
This interview with Steering Committee member, Atsushi Tanaka, MD, focuses on his recent article from PNAS on Round Spermatid ... This interview with Steering Committee member, Atsushi Tanaka, MD, focuses on his recent article from PNAS on Round Spermatid ... This interview with Steering Committee member, Atsushi Tanaka, MD, focuses on his recent article from PNAS on Round Spermatid ...
A spermatid is a haploid male germ cell that has completed the process of meiosis. Immediately after meiosis, spermatids are ... Round spermatids must go through the process of spermiogenesis in the testis to form structures, such as the head, tail, and ...
Learn about the importance of distinguishing spermatids from WBCs during a semen analysis from a clinical standpoint. ... Therefore distinguishing spermatids from WBCs during a semen analysis is of great clinical value. Using the QwikCheck Test ... What is the clinical relevance of distinguishing spermatids from WBCs during a semen analysis?. Home ... The test can be useful in distinguishing polymorphonuclear leukocytes from multinucleated spermatids, which are peroxidase-free ...
Round spermatid injection (ROSI)[edit]. Round spermatid injection (ROSI) is a technique of assisted reproduction whereby a ... Moreover, the distinction between living round spermatids, to be used in ROSI, and dead round spermatids, to be discarded, ... Consequently, the distinction between round spermatids and other round cells of similar size, such as leukocytes, is not an ... If all requirements for round spermatid selection and injection are successfully met, the injected oocytes develop to early ...
Crunch Times news provides daily news articles on Sports but it is not to be taken as a reference or resource for interpretations. All authors and contributors have editorial freedom and their article advice should not be considered while making your financial ...
Sequence of the development of the acrosomal cap in spermatids from guinea pig testis, as observed in electron microscopic ... Don W. Fawcett (2011) CIL:11370, Cavia porcellus, spermatid. CIL. Dataset. https://doi.org/doi:10.7295/W9CIL11370 ...
... we cloned and characterized a new spermatid-specific protein gene, ssp411, from adult rat testes. The ssp411 cDNA shared ... "Cloning and characterization of rat spermatid protein SSP411: A thioredoxin-like protein," Journal of Andrology 25(4): 479-493. ... Cloning and characterization of rat spermatid protein SSP411: A thioredoxin-like protein. ... we cloned and characterized a new spermatid-specific protein gene, ssp411, from adult rat testes. The ssp411 cDNA shared ...
Permeability changes induced by polylysines in rat spermatids. / Jorquera, Ramon A.; Berrios, Julio; Sans, Jorge et al. In: ... Permeability changes induced by polylysines in rat spermatids. In: Biology of the Cell. 2002 ; Vol. 94, No. 4-5. pp. 233-241. ... Permeability changes induced by polylysines in rat spermatids. Ramon A. Jorquera, Julio Berrios, Jorge Sans, Cecilia Vergara, ... Permeability changes induced by polylysines in rat spermatids. Biology of the Cell. 2002 Sep;94(4-5):233-241. doi: 10.1016/ ...
... like protein HILS1 01018376711 at Gentaur Spermatid specific linker histone H1 like protein, HILS1 ... Order Human Spermatid- specific linker histone H1- ... Human Spermatid- specific linker histone H1- like protein, ...
Although round spermatid injection can be used to create progeny for males who do not produce mature sperm, the rate of ... Epigenetic abnormalities of the mouse paternal zygotic genome associated with microinsemination of round spermatids.在哪里下载?这篇文献在 ... Genomes from elongated spermatids exhibited an intermediate level of DNA methylation, between those of round spermatids and ... Although round spermatid injection can be used to create progeny for males who do not produce mature sperm, the rate of ...
Shyu HW, Hsu SH, Hsieh-Li HM, Li H. A novel member of the RBCC family, Trif, expressed specifically in the spermatids of mouse ... A novel member of the RBCC family, Trif, expressed specifically in the spermatids of mouse testis. / Shyu, Huey Wen; Hsu, Shih ... A novel member of the RBCC family, Trif, expressed specifically in the spermatids of mouse testis. In: Mechanisms of ... Dive into the research topics of A novel member of the RBCC family, Trif, expressed specifically in the spermatids of mouse ...
title = "Stimulation of Spermatid Phosphofructokinase by Fructose 2,6‐Bisphosphate from Rat Testes: fructose 2, 6‐bisphosphate/ ... Stimulation of Spermatid Phosphofructokinase by Fructose 2,6‐Bisphosphate from Rat Testes: fructose 2, 6‐bisphosphate/ ... Stimulation of Spermatid Phosphofructokinase by Fructose 2,6‐Bisphosphate from Rat Testes: fructose 2, 6‐bisphosphate/ ... Stimulation of Spermatid Phosphofructokinase by Fructose 2,6‐Bisphosphate from Rat Testes: fructose 2, 6‐bisphosphate/ ...
involved_in spermatid development IEA Inferred from Electronic Annotation. more info. involved_in spermatogenesis ISS Inferred ...
involved_in spermatid development IBA Inferred from Biological aspect of Ancestor. more info ...
TEM showed that numerous autophagosomes were developed inside spermatids. Many endoplasmic reticulum (ER) were transferred into ... TEM showed that numerous autophagosomes were developed inside spermatids. Many endoplasmic reticulum (ER) were transferred into ... The testis expressed LC3-II protein, which was located within spermatids at different stages of differentiation and indicated ... The testis expressed LC3-II protein, which was located within spermatids at different stages of differentiation and indicated ...
After 14 days, they report, spermatid-like cells developed. Spermatids are not mature sperm: they are round, rather than having ... The researchers injected the spermatids directly into mouse eggs; this led to offspring which, at 15 months, appear healthy, ... it takes more than 4 weeks for the PGC to become a spermatid, for example, but the Chinese team reports a 14-day interval ... although he cautions that it is hard to know whether the artificial spermatids do behave exactly like their natural ...
Molecular genetic analysis of mammalian spermatid differentiation  Schumacher, Jill M.; Fajardo, Mark A.; Braun, Robert E.; ... Previous studies in transgenic mice have established the importance of the 3 untranslated region (UTR) of the spermatid- ...
Recently, success was obtained with spermatids from testicular biopsies.. The potential transmission of a genetic abnormality ...
... role in the ectoplasmic specialization and at the tubulobulbar complexes of Sertoli cells attaching the head of late spermatids ... and chromatoid bodies of round spermatids. In addition, PRKRA is associated with dense material surrounding tubulobulbar ... Next we observed spermatids. In step 1-6 spermatids, large granules were stained for PRKRA (Figures 2(a) and 2(e)). By dual ... g) A rat step 5 spermatids. (h) A mouse step 4 spermatid. (i) Control for 60-90P. (j) Control for ISPG. (k) Control for IMC. (l ...
Early spermatids [nTPM] * Endometrial stromal cells [nTPM] * Endothelial cells [nTPM] * Enteroendocrine cells [nTPM] ...
Early spermatids [nTPM] * Endometrial stromal cells [nTPM] * Endothelial cells [nTPM] * Enteroendocrine cells [nTPM] ...
... and form an acrosome in wild-type spermatids and a pseudoacrosome in Hrb mutant spermatids. We suggest that nucleopodes develop ... Male mice with a Hrb null mutation are infertile and both spermatids and sperm are round-headed and lack an acrosome. Hrb, a ... Here we report that the lack of an acrosome in Hrb mutant spermatids does not prevent the development of the acroplaxome. Yet ... Histone H1-like protein in spermatids 1 (Hils1) is a testis- specific histone H1-like protein exclusively expressed in haploid ...
... spermatids; scheme according to (Nobrega et al., 2009). Lower panel: Staining with anti-repeat1 antibody (red, left) and ...
  • In situ hybridization indicated that Trif is expressed in the round spermatids of the seminiferous tubules. (ntnu.edu.tw)
  • The results suggest that PRKRA functions in the nuage as an element of RNA silencing system and plays unknown role in the ectoplasmic specialization and at the tubulobulbar complexes of Sertoli cells attaching the head of late spermatids. (hindawi.com)
  • ARMC12 is mainly expressed in the midpiece of elongated and late spermatids in the human testis. (nih.gov)
  • Round spermatids must go through the process of spermiogenesis in the testis to form structures, such as the head, tail, and acrosome and to become elongated spermatids. (repropedia.org)
  • Figure 205 from Chapter 6 (Golgi Apparatus) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Sequence of the development of the acrosomal cap in spermatids from guinea pig testis, as observed in electron microscopic images. (ucsd.edu)
  • The testis expressed LC3-II protein, which was located within spermatids at different stages of differentiation and indicated active autophagy. (frontiersin.org)
  • A spermatozoon is a highly differentiated cell developed from a spermatid through spermiogenesis in the convoluted seminiferous tubule of the testis. (frontiersin.org)
  • Here, we report an important role for Rlim in testis where it is highly expressed in post-meiotic round spermatids as well as in Sertoli cells. (umass.edu)
  • The spermatid is the haploid male gametid that results from division of secondary spermatocytes. (wikipedia.org)
  • 2000). They can sometimes be differentiated from spermatids and spermatocytes in a semen smear stained with the Papanicolaou procedure. (mes-global.com)
  • PRKRA localized to four types of nuage structures, including aggregates of 60-90 nm particles, irregularly-shaped perinuclear granules, and intermitochondrial cement of pachytene spermatocytes, and chromatoid bodies of round spermatids. (hindawi.com)
  • Histology evaluation: Abnormal spermiogenesis with accumulation of meiotic division-phase spermatocytes and degenerating round spermatids present in multinucleated cell bodies (see 1). (jax.org)
  • Spermatids and spermatocytes were about 10 to 20 times more sensitive to germ cell differences than spermatozoa. (cdc.gov)
  • In spermatogenesis, each germinal cell (spermatogonium), located adjacent to the Sertoli cells, undergoes differentiation into 16 primary spermatocytes, each of which generates 4 spermatids. (msdmanuals.com)
  • When formed, early round spermatids must undergo further maturational events to develop into spermatozoa, a process termed spermiogenesis (also termed spermeteliosis). (wikipedia.org)
  • Genomes from elongated spermatids exhibited an intermediate level of DNA methylation, between those of round spermatids and mature spermatozoa, suggesting that the male germ cell acquires the ability to maintain its undermethylated state in the paternal zygotic genome during this phase of spermiogenesis. (shengsci.com)
  • The plasma membrane of the spermatid invaginated to form vesicles that were distributed among various endosomes around the CFC during spermiogenesis. (frontiersin.org)
  • All this cellular evidence suggests that, in vivo , IM was developed mainly by CFC produced from ER within differentiating spermatids during spermiogenesis. (frontiersin.org)
  • Histology evaluation: Abnormal spermiogenesis (see 1) characterized by abnormally shaped spermatid heads and abnormal tail morphology. (jax.org)
  • These results reveal functions of Rlim in male reproduction specifically in round spermatids during spermiogenesis. (umass.edu)
  • The spermatids begin to grow a living thread, develop a thickened mid-piece where the mitochondria become localised, and form an acrosome. (wikipedia.org)
  • Figures 206 (upper) and 207 (lower) from Chapter 6 (Golgi Apparatus) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. During development of the acrosome in the chinchilla spermatid, the transitional zon. (ucsd.edu)
  • A spermatid is a haploid male germ cell that has completed the process of meiosis. (repropedia.org)
  • Scheme showing analogies in the process of maturation of the ovum and the development of the Genyo spermatids (young spermatozoa) List of distinct cell types in the adult human body Cyranoski, David (25 February 2016). (wikipedia.org)
  • [2] In the first place, as compared to spermatozoa, round spermatids do not possess easily perceptible morphological characteristics and are immotile. (wikipedia.org)
  • Although round spermatid injection can be used to create progeny for males who do not produce mature sperm, the rate of successful embryogenesis after such procedures is significantly lower than that for similar procedures using mature spermatozoa. (shengsci.com)
  • At 25 days of age, round spermatids appear, and at the age of 50 days, mature spermatozoa are released into seminiferous tubular lumen [ 20 , 21 ]. (hindawi.com)
  • The lowest effective exposure for spermatozoa was 18ppm for one hour or 0.25ppm for 72 hours, while in spermatids, the lowest effective exposure of 2.3ppm for an hour or compared to spermatozoa. (cdc.gov)
  • In an attempt to identify new sperm-specific genes that are involved in sperm maturation, fertilization, and embryo development, such as the mammalian ortholog of the sperm-supplied protein gene, spe-11, in Caenorhabditis elegans, we cloned and characterized a new spermatid-specific protein gene, ssp411, from adult rat testes. (popcouncil.org)
  • Effect of fructose 2, 6‐bisphosphate on 6‐phosphofructokinase (ATP: D‐fructose‐6‐phosphate 1‐phosphotransferase, EC 2.7.1.11) in spermatid extract from rat testes was studied. (elsevierpure.com)
  • This stimulation may play an important role in the regulation of glycolysis in spermatids of rat testes. (elsevierpure.com)
  • To this end, a culture system for isolated, pupal testes and isolated spermatid bundles (cysts) was established in this work. (uni-marburg.de)
  • This compromised testicular antioxidant status might have contributed to poor growth and development by affecting the spermatogenesis and steroidogenesis in rats before puberty as indicated by reduced germ cell number, complete absence of round spermatids, decreased seminiferous tubule diameter, and decreased testosterone level. (hindawi.com)
  • As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte. (wikipedia.org)
  • Immediately after meiosis, spermatids are round cells that do not resemble mature sperm. (repropedia.org)
  • In those men in whom spermatogenesis is blocked at the stage of round spermatids, in which meiosis has already been completed, these round cells can successfully fertilize oocytes after being injected into their cytoplasm. (wikipedia.org)
  • 15 kDa) polylysines (PLs) bound and induced permeability changes in rat spermatid plasma membranes, estimated by Mn 2+ quenching of intracellular indo-1 fluorescence (K 1/2 = 3.3 ± 0.5 μg/ml) and Co 2+ quenching of intracellular calcein. (pucv.cl)
  • This interview with Steering Committee member, Atsushi Tanaka, MD, focuses on his recent article from PNAS on Round Spermatid Injection, or ROSI. (reachmd.com)
  • Round spermatid injection (ROSI) is a technique of assisted reproduction whereby a round spermatid is injected into oocyte cytoplasm in order to achieve fertilization. (wikipedia.org)
  • [2] The microinjection procedure for ROSI also differs slightly from that of ICSI, since additional stimuli are needed to ensure proper oocyte activation after spermatid injection. (wikipedia.org)
  • If all requirements for round spermatid selection and injection are successfully met, the injected oocytes develop to early embryos and can be transferred to the mother's uterus to produce pregnancy. (wikipedia.org)
  • Moreover, the distinction between living round spermatids, to be used in ROSI, and dead round spermatids, to be discarded, needs specific methods and skills, not required in the case of ICSI where sperm cell viability can be easily evaluated on the basis of sperm motility in most cases. (wikipedia.org)
  • Spermatids are connected by cytoplasmic material and have superfluous cytoplasmic material around their nuclei. (wikipedia.org)
  • The CFC was more developed in spermatids with compact nuclei than in spermatids with granular nuclei. (frontiersin.org)
  • In addition, treatment of zygotes with trichostatin A led to a significant reduction in DNA methylation, specifically in the spermatid-derived paternal genome, except for the pericentromeric regions enriched by trimethylation of Lys9 of histone H3. (shengsci.com)
  • Inhibition of type I and II topoisomerases had no effect on the development of postmeiotic spermatids and the completion of the H-P switch. (uni-marburg.de)
  • These structures first appear in the cytoplasmic lobe of elongated step 10 spermatids and subsequently disappear in step 19 spermatids. (hindawi.com)
  • And other stages of germ-cell development occurred unexpectedly quickly: in a real mouse, it takes more than 4 weeks for the PGC to become a spermatid, for example, but the Chinese team reports a 14-day interval between artificial PGC and spermatid. (scientificamerican.com)
  • In 2016 scientists at Nanjing Medical University claimed they had produced cells resembling mouse spermatids artificially from stem cells. (wikipedia.org)
  • They injected these spermatids into mouse eggs and produced pups. (wikipedia.org)
  • Consequently, the distinction between round spermatids and other round cells of similar size, such as leukocytes, is not an easy task. (wikipedia.org)
  • After 14 days, they report, spermatid-like cells developed. (scientificamerican.com)
  • Spermatids are not mature sperm: they are round, rather than having sperm's elongated shape, and cannot swim. (scientificamerican.com)
  • Azim Surani, a developmental biologist at the University of Cambridge, UK, says that the results are "encouraging", although he cautions that it is hard to know whether the artificial spermatids do behave exactly like their natural counterparts. (scientificamerican.com)
  • Spermatid DNA also undergoes packaging, becoming highly condensed. (wikipedia.org)
  • In this study, we demonstrate that, unlike the normal paternal genome, the paternal zygotic genome derived from a round spermatid is highly remethylated before first mitosis after demethylation. (shengsci.com)
  • The DNA is packaged firstly with specific nuclear basic proteins, which are subsequently replaced with protamines during spermatid elongation. (wikipedia.org)
  • In particular, the repair of DNA double-strand breaks by the non-homologous end joining pathway, although present in round spermatids, appears to be lost as they develop into elongated spermatids. (wikipedia.org)
  • Distribution specificity of human fucosyltransferase 5 and its expression and localization in spermatids]. (bvsalud.org)
  • 2000). Polymorphonuclear leukocytes can easily be confused morphologically with multinucleated spermatids, but stain a bluish colour, in contrast to the more pinkish colour of spermatids (Johanisson et al. (mes-global.com)