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.

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.

A count of SPERM in the ejaculum, expressed as number per milliliter.

The process by which semen is kept viable outside of the organism from which it was derived (i.e., kept from decay by means of a chemical agent, cooling, or a fluid substitute that mimics the natural state within the organism).

The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.

The thick, yellowish-white, viscid fluid secretion of male reproductive organs discharged upon ejaculation. In addition to reproductive organ secretions, it contains SPERMATOZOA and their nutrient plasma.

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.

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.

The inability of the male to effect FERTILIZATION of an OVUM after a specified period of unprotected intercourse. Male sterility is permanent infertility.

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 posterior filiform portion of the spermatozoon (SPERMATOZOA) that provides sperm motility.

Passive or active movement of SPERMATOZOA from the testicular SEMINIFEROUS TUBULES through the male reproductive tract as well as within the female reproductive tract.

The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.

The structural and functional changes by which SPERMATOZOA become capable of oocyte FERTILIZATION. It normally requires exposing the sperm to the female genital tract for a period of time to bring about increased SPERM MOTILITY and the ACROSOME REACTION before fertilization in the FALLOPIAN TUBES can take place.

A condition in which the percentage of progressively motile sperm is abnormally low. In men, it is defined as

The quality of SEMEN, an indicator of male fertility, can be determined by semen volume, pH, sperm concentration (SPERM COUNT), total sperm number, sperm viability, sperm vigor (SPERM MOTILITY), normal sperm morphology, ACROSOME integrity, and the concentration of WHITE BLOOD CELLS.

Changes that occur to liberate the enzymes of the ACROSOME of a sperm (SPERMATOZOA). Acrosome reaction allows the sperm to penetrate the ZONA PELLUCIDA and enter the OVUM during FERTILIZATION.

Preservation of cells, tissues, organs, or embryos by freezing. In histological preparations, cryopreservation or cryofixation is used to maintain the existing form, structure, and chemical composition of all the constituent elements of the specimens.

The fusion of a spermatozoon (SPERMATOZOA) with an OVUM thus resulting in the formation of a ZYGOTE.

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.

The capacity to conceive or to induce conception. It may refer to either the male or female.

Interactive processes between the oocyte (OVUM) and the sperm (SPERMATOZOA) including sperm adhesion, ACROSOME REACTION, sperm penetration of the ZONA PELLUCIDA, and events leading to FERTILIZATION.

A tough transparent membrane surrounding the OVUM. It is penetrated by the sperm during FERTILIZATION.

The motor activity of the GASTROINTESTINAL TRACT.

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.

Artificial introduction of SEMEN or SPERMATOZOA into the VAGINA to facilitate FERTILIZATION.

The middle piece of the spermatozoon is a highly organized segment consisting of MITOCHONDRIA, the outer dense fibers and the core microtubular structure.

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).

The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA.

Substances that provide protection against the harmful effects of freezing temperatures.

The secretory proteins of the seminal vesicles are proteins and enzymes that are important in the rapid clotting of the ejaculate. The major clotting protein is seminal vesicle-specific antigen. Many of these seminal vesicle proteins are under androgen regulation, and are substrates for the prostatic enzymes, such as the PROSTATE-SPECIFIC ANTIGEN, a protease and an esterase.

An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro.

Proteins found in SEMEN. Major seminal plasma proteins are secretory proteins from the male sex accessory glands, such as the SEMINAL VESICLES and the PROSTATE. They include the seminal vesicle-specific antigen, an ejaculate clotting protein; and the PROSTATE-SPECIFIC ANTIGEN, a protease and an esterase.

A chlorinated PROPANEDIOL with antifertility activity in males used as a chemosterilant in rodents.

A pair of highly specialized muscular canals extending from the UTERUS to its corresponding OVARY. They provide the means for OVUM collection, and the site for the final maturation of gametes and FERTILIZATION. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three histologic layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells.

Centers for acquiring and storing semen.

A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)

Chemical substances or agents with contraceptive activity in males. Use for male contraceptive agents in general or for which there is no specific heading.

Male germ cells derived from the haploid secondary SPERMATOCYTES. Without further division, spermatids undergo structural changes and give rise to SPERMATOZOA.

A trypsin-like enzyme of spermatozoa which is not inhibited by alpha 1 antitrypsin.

Agglutination of spermatozoa by antibodies or autoantibodies.

A slightly alkaline secretion of the endocervical glands. The consistency and amount are dependent on the physiological hormone changes in the menstrual cycle. It contains the glycoprotein mucin, amino acids, sugar, enzymes, and electrolytes, with a water content up to 90%. The mucus is a useful protection against the ascent of bacteria and sperm into the uterus. (From Dictionary of Obstetrics and Gynecology, 1988)

Chemical substances with sperm immobilizing activity used as topically administered vaginal contraceptives.

The male reproductive organs. They are divided into the external organs (PENIS; SCROTUM;and URETHRA) and the internal organs (TESTIS; EPIDIDYMIS; VAS DEFERENS; SEMINAL VESICLES; EJACULATORY DUCTS; PROSTATE; and BULBOURETHRAL GLANDS).

Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.

Surgical removal of the ductus deferens, or a portion of it. It is done in association with prostatectomy, or to induce infertility. (Dorland, 28th ed)

A polyvinyl polymer of variable molecular weight; used as suspending and dispersing agent and vehicle for pharmaceuticals; also used as blood volume expander.

A mature haploid female germ cell extruded from the OVARY at OVULATION.

Somewhat flattened, globular echinoderms, having thin, brittle shells of calcareous plates. They are useful models for studying FERTILIZATION and EMBRYO DEVELOPMENT.

Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).

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)

Any of various ruminant mammals of the order Bovidae. They include numerous species in Africa and the American pronghorn.

A genus of long-legged, swift-moving felines (FELIDAE) from Africa (and formerly Asia) about the size of a small leopard.

Human artificial insemination in which the husband's semen is used.

Liquids transforming into solids by the removal of heat.

A saclike, glandular diverticulum on each ductus deferens in male vertebrates. It is united with the excretory duct and serves for temporary storage of semen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.

Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).

Cytoplasm stored in an egg that contains nutritional reserves for the developing embryo. It is rich in polysaccharides, lipids, and proteins.

A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.

The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.

Any of the compounds derived from a group of glycols or polyhydroxy alcohols by chlorine substitution for part of the hydroxyl groups. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

Procedures to obtain viable sperm from the male reproductive tract, including the TESTES, the EPIDIDYMIS, or the VAS DEFERENS.

The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.

The ratio of the number of conceptions (CONCEPTION) including LIVE BIRTH; STILLBIRTH; and fetal losses, to the mean number of females of reproductive age in a population during a set time period.

A condition characterized by the dilated tortuous veins of the SPERMATIC CORD with a marked left-sided predominance. Adverse effect on male fertility occurs when varicocele leads to an increased scrotal (and testicular) temperature and reduced testicular volume.

Glycosidic antibiotic from Streptomyces griseus used as a fluorescent stain of DNA and as an antineoplastic agent.

A TETRACYCLINE with a 7-chloro substitution.

A METHYLXANTHINE derivative that inhibits phosphodiesterase and affects blood rheology. It improves blood flow by increasing erythrocyte and leukocyte flexibility. It also inhibits platelet aggregation. Pentoxifylline modulates immunologic activity by stimulating cytokine production.

Chemical agents that increase the permeability of biological or artificial lipid membranes to specific ions. Most ionophores are relatively small organic molecules that act as mobile carriers within membranes or coalesce to form ion permeable channels across membranes. Many are antibiotics, and many act as uncoupling agents by short-circuiting the proton gradient across mitochondrial membranes.

The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.

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.

A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.

The total process by which organisms produce offspring. (Stedman, 25th ed)

A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.

A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.

The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.

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.

Splitting the DNA into shorter pieces by endonucleolytic DNA CLEAVAGE at multiple sites. It includes the internucleosomal DNA fragmentation, which along with chromatin condensation, are considered to be the hallmarks of APOPTOSIS.

The deposit of SEMEN or SPERMATOZOA into the VAGINA to facilitate FERTILIZATION.

Solutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.

Elements of limited time intervals, contributing to particular results or situations.

Lectin purified from peanuts (ARACHIS HYPOGAEA). It binds to poorly differentiated cells and terminally differentiated cells and is used in cell separation techniques.

Methods for controlling genetic SEX of offspring.

An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.

Procedures for collecting, preserving, and transporting of specimens sufficiently stable to provide accurate and precise results suitable for clinical interpretation.

Chemical substances that are destructive to spermatozoa used as topically administered vaginal contraceptives.

The male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans and in some other male-heterogametic species in which the homologue of the X chromosome has been retained.

Liquid components of living organisms.

A form of interference microscopy in which variations of the refracting index in the object are converted into variations of intensity in the image. This is achieved by the action of a phase plate.

A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, and sweetening agent.

An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.

Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.

Sexual stimulation or gratification of the self.

Inbred ICR mice are a strain of albino laboratory mice that have been selectively bred for consistent genetic makeup and high reproductive performance, making them widely used in biomedical research for studies involving reproduction, toxicology, pharmacology, and carcinogenesis.

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.

The plasma membrane of the egg.

Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.

A structurally-diverse family of intracellular-signaling adaptor proteins that selectively tether specific protein kinase A subtypes to distinct subcellular sites. They play a role in focusing the PROTEIN KINASE A activity toward relevant substrates. Over fifty members of this family exist, most of which bind specifically to regulatory subunits of CYCLIC AMP-DEPENDENT PROTEIN KINASE TYPE II such as CAMP PROTEIN KINASE RIIALPHA or CAMP PROTEIN KINASE RIIBETA.

Process of using a rotating machine to generate centrifugal force to separate substances of different densities, remove moisture, or simulate gravitational effects. It employs a large motor-driven apparatus with a long arm, at the end of which human and animal subjects, biological specimens, or equipment can be revolved and rotated at various speeds to study gravitational effects. (From Websters, 10th ed; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Ducts that serve exclusively for the passage of eggs from the ovaries to the exterior of the body. In non-mammals, they are termed oviducts. In mammals, they are highly specialized and known as FALLOPIAN TUBES.

Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.

'Zoo animals' are various species of captive wild animals, housed and displayed in a facility for the purpose of public education, conservation, research, and recreation.

Fleshy and reddish outgrowth of skin tissue found on top of the head, attached to the sides of the head, and hanging from the mandible of birds such as turkeys and chickens.

Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.

Proteins which are found in eggs (OVA) from any species.

Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.

Cell separation is the process of isolating and distinguishing specific cell types or individual cells from a heterogeneous mixture, often through the use of physical or biological techniques.

Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.

The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.

The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Inability to reproduce after a specified period of unprotected intercourse. Reproductive sterility is permanent infertility.

A family of anadromous fish comprising SALMON; TROUT; whitefish; and graylings. They are the most important food and game fishes. Their habitat is the northern Atlantic and Pacific, both marine and inland, and the Great Lakes. (Nelson: Fishes of the World, 1976, p97)

A species of the true toads, Bufonidae, found in South America.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.

The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.

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.

Results of conception and ensuing pregnancy, including LIVE BIRTH; STILLBIRTH; SPONTANEOUS ABORTION; INDUCED ABORTION. The outcome may follow natural or artificial insemination or any of the various ASSISTED REPRODUCTIVE TECHNIQUES, such as EMBRYO TRANSFER or FERTILIZATION IN VITRO.

The measurement of an organ in volume, mass, or heaviness.

A cutaneous pouch of skin containing the testicles and spermatic cords.

The application of LUBRICANTS to diminish FRICTION between two surfaces.

The chromosomal constitution of cells which deviate from the normal by the addition or subtraction of CHROMOSOMES, chromosome pairs, or chromosome fragments. In a normally diploid cell (DIPLOIDY) the loss of a chromosome pair is termed nullisomy (symbol: 2N-2), the loss of a single chromosome is MONOSOMY (symbol: 2N-1), the addition of a chromosome pair is tetrasomy (symbol: 2N+2), the addition of a single chromosome is TRISOMY (symbol: 2N+1).

The relationship between the dose of an administered drug and the response of the organism to the drug.

Disorders affecting the motor function of the UPPER ESOPHAGEAL SPHINCTER; LOWER ESOPHAGEAL SPHINCTER; the ESOPHAGUS body, or a combination of these parts. The failure of the sphincters to maintain a tonic pressure may result in gastric reflux of food and acid into the esophagus (GASTROESOPHAGEAL REFLUX). Other disorders include hypermotility (spastic disorders) and markedly increased amplitude in contraction (nutcracker esophagus).

'Poisonous fishes' are aquatic organisms belonging to the Phylum Chordata and Class Pisces, that contain toxic substances either in their tissues or secretions, which can cause harmful or lethal effects when ingested, touched, or coming into contact with their released toxins.

The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.

A condition of having no sperm present in the ejaculate (SEMEN).

The species Physeter catodon (also called Physeter macrocephalus), in the family Physeteridae. The common name is derived from the milky wax substance in its head (spermaceti). The species also produces an intestinal secretion AMBERGRIS, which was previously used in perfumes. The sperm whale is the largest toothed MAMMAL in the world.

The network of channels formed at the termination of the straight SEMINIFEROUS TUBULES in the mediastinum testis. Rete testis channels drain into the efferent ductules that pass into the caput EPIDIDYMIS.

Sexual union of a male and a female in non-human species.

A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and LEYDIG CELLS. FSH consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.

Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.

Agents, either mechanical or chemical, which destroy spermatozoa in the male genitalia and block spermatogenesis.

Sexual activities of animals.

Refraining from SEXUAL INTERCOURSE.

A form of fluorescent antibody technique commonly used to detect serum antibodies and immune complexes in tissues and microorganisms in specimens from patients with infectious diseases. The technique involves formation of an antigen-antibody complex which is labeled with fluorescein-conjugated anti-immunoglobulin antibody. (From Bennington, Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)

Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.

An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.

A technique that uses LASERS to trap, image, and manipulate small objects (biomolecules, supramolecular assembles, DENDRIMERS) in three dimensional space. (From Glossary of Biotechnology and Nanobiotechnology Terms, 4th ed.)

A family of multisubunit cytoskeletal motor proteins that use the energy of ATP hydrolysis to power a variety of cellular functions. Dyneins fall into two major classes based upon structural and functional criteria.

A group of enzymes that are dependent on CYCLIC AMP and catalyze the phosphorylation of SERINE or THREONINE residues on proteins. Included under this category are two cyclic-AMP-dependent protein kinase subtypes, each of which is defined by its subunit composition.

Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.

The fertilized OVUM resulting from the fusion of a male and a female gamete.

Histochemical localization of immunoreactive substances using labeled antibodies as reagents.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

A form of male HYPOGONADISM, characterized by the presence of an extra X CHROMOSOME, small TESTES, seminiferous tubule dysgenesis, elevated levels of GONADOTROPINS, low serum TESTOSTERONE, underdeveloped secondary sex characteristics, and male infertility (INFERTILITY, MALE). Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several karyotype variants include 48,XXYY; 48,XXXY; 49,XXXXY, and mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).

A species of PERCIFORMES commonly used in saline aquaculture.

A plant genus of the family Caricaceae, order Violales, subclass Dilleniidae, class Magnoliopsida. It is the source of edible fruit and PAPAIN.

The transfer of mammalian embryos from an in vivo or in vitro environment to a suitable host to improve pregnancy or gestational outcome in human or animal. In human fertility treatment programs, preimplantation embryos ranging from the 4-cell stage to the blastocyst stage are transferred to the uterine cavity between 3-5 days after FERTILIZATION IN VITRO.

An enzyme bound to the inner mitochondrial membrane that catalyzes the oxidation of CHOLINE to BETAINE.

Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.

Morphological and physiological development of EMBRYOS or FETUSES.

An organophosphorus insecticide that inhibits ACETYLCHOLINESTERASE.

Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.

An animal or plant species in danger of extinction. Causes can include human activity, changing climate, or change in predator/prey ratios.

Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.

A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.

An infraclass of MAMMALS, also called Metatheria, where the young are born at an early stage of development and continue to develop in a pouch (marsupium). In contrast to Eutheria (placentals), marsupials have an incomplete PLACENTA.

The performance of dissections, injections, surgery, etc., by the use of micromanipulators (attachments to a microscope) that manipulate tiny instruments.

Morphological and physiological development of EMBRYOS.

Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.

The excretory duct of the testes that carries SPERMATOZOA. It rises from the SCROTUM and joins the SEMINAL VESICLES to form the ejaculatory duct.

A drug formerly used in the treatment of angina pectoris but superseded by less hazardous drugs. Prenylamine depletes myocardial catecholamine stores and has some calcium channel blocking activity. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1406)

Clinical and laboratory techniques used to enhance fertility in humans and animals.

N-(1-Oxobutyl)-cyclic 3',5'-(hydrogen phosphate)-2'-butanoate guanosine. A derivative of cyclic GMP. It has a higher resistance to extracellular and intracellular phosphodiesterase than cyclic GMP.

A family of herbivorous leaping MAMMALS of Australia, New Guinea, and adjacent islands. Members include kangaroos, wallabies, quokkas, and wallaroos.

Serum albumin from cows, commonly used in in vitro biological studies. (From Stedman, 25th ed)

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.

The reproductive cells in multicellular organisms at various stages during GAMETOGENESIS.

Common name for a number of different species of fish in the family Cyprinidae. This includes, among others, the common carp, crucian carp, grass carp, and silver carp.

Peptides and proteins found in BODILY SECRETIONS and BODY FLUIDS that are PROTEASE INHIBITORS. They play a role in INFLAMMATION, tissue repair and innate immunity (IMMUNITY, INNATE) by inhibiting endogenous proteinases such as those produced by LEUKOCYTES and exogenous proteases such as those produced by invading microorganisms.

Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)

The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)

A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.

Chemical agents or odors that stimulate sexual desires. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)