Compounds that interfere with FATTY ACID SYNTHASE resulting in a reduction of FATTY ACIDS. This is a target mechanism in humans of some ANTINEOPLASTIC AGENTS and ANTI-OBESITY AGENTS and of some ANTI-INFECTIVE AGENTS which interfere with CELL WALL and CELL MEMBRANE formation.
Compounds that inhibit cell production of DNA or RNA.
An epoxydodecadienamide isolated from several species, including ACREMONIUM, Acrocylindrum, and Helicoceras. It inhibits the biosynthesis of several lipids by interfering with enzyme function.
High molecular weight polymers containing a mixture of purine and pyrimidine nucleotides chained together by ribose or deoxyribose linkages.
Gram-negative, capsulated, gas-producing rods found widely in nature. Both motile and non-motile strains exist. The species is closely related to KLEBSIELLA PNEUMONIAE and is frequently associated with nosocomial infections
Uridine is a nucleoside, specifically a derivative of pyrimidine, that is composed of a uracil molecule joined to a ribose sugar molecule through a β-N1 glycosidic bond, and has significant roles in RNA synthesis, energy transfer, and cell signaling.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Compounds which inhibit the synthesis of proteins. They are usually ANTI-BACTERIAL AGENTS or toxins. Mechanism of the action of inhibition includes the interruption of peptide-chain elongation, the blocking the A site of ribosomes, the misreading of the genetic code or the prevention of the attachment of oligosaccharide side chains to glycoproteins.
The chemical reactions that occur within the cells, tissues, or an organism. These processes include both the biosynthesis (ANABOLISM) and the breakdown (CATABOLISM) of organic materials utilized by the living organism.
Thymidine is a pyrimidine nucleoside, consisting of a thymine base linked to a deoxyribose sugar by a β-N1-glycosidic bond, which plays a crucial role in DNA replication and repair processes as one of the four nucleosides in DNA.
Stable phosphorus atoms that have the same atomic number as the element phosphorus, but differ in atomic weight. P-31 is a stable phosphorus isotope.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Tritium is an isotope of hydrogen (specifically, hydrogen-3) that contains one proton and two neutrons in its nucleus, making it radioactive with a half-life of about 12.3 years, and is used in various applications including nuclear research, illumination, and dating techniques due to its low energy beta decay.
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
DNA analogs containing neutral amide backbone linkages composed of aminoethyl glycine units instead of the usual phosphodiester linkage of deoxyribose groups. Peptide nucleic acids have high biological stability and higher affinity for complementary DNA or RNA sequences than analogous DNA oligomers.
Uracil is a nitrogenous base, specifically a pyrimidine derivative, which constitutes one of the four nucleobases in the nucleic acid of RNA (ribonucleic acid), pairing with adenine via hydrogen bonds during base-pairing. (25 words)
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
Antibiotic substance isolated from streptomycin-producing strains of Streptomyces griseus. It acts by inhibiting elongation during protein synthesis.
A purine base and a fundamental unit of ADENINE NUCLEOTIDES.
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
An antibiotic isolated from various Streptomyces species. It interferes with protein and DNA synthesis by inhibiting peptidyl transferase or the 80S ribosome system.
Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. (Webster, 3d ed)
The rate dynamics in chemical or physical systems.
The process by which a DNA molecule is duplicated.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Elements of limited time intervals, contributing to particular results or situations.
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
The principal alkaloid of ipecac, from the ground roots of Uragoga (or Cephaelis) ipecacuanha or U. acuminata, of the Rubiaceae. It is used as an amebicide in many different preparations and may cause serious cardiac, hepatic, or renal damage and violent diarrhea and vomiting. Emetine inhibits protein synthesis in EUKARYOTIC CELLS but not PROKARYOTIC CELLS.
A cinnamamido ADENOSINE found in STREPTOMYCES alboniger. It inhibits protein synthesis by binding to RNA. It is an antineoplastic and antitrypanosomal agent and is used in research as an inhibitor of protein synthesis.
A compound composed of a two CYCLIC PEPTIDES attached to a phenoxazine that is derived from STREPTOMYCES parvullus. It binds to DNA and inhibits RNA synthesis (transcription), with chain elongation more sensitive than initiation, termination, or release. As a result of impaired mRNA production, protein synthesis also declines after dactinomycin therapy. (From AMA Drug Evaluations Annual, 1993, p2015)
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
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.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Nucleic acid which complements a specific mRNA or DNA molecule, or fragment thereof; used for hybridization studies in order to identify microorganisms and for genetic studies.
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.
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
Laboratory techniques that involve the in-vitro synthesis of many copies of DNA or RNA from one original template.
Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones.
Enzymes that catalyze the synthesis of FATTY ACIDS from acetyl-CoA and malonyl-CoA derivatives.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
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 genus of the family CORONAVIRIDAE which causes respiratory or gastrointestinal disease in a variety of vertebrates.
A country spanning from central Asia to the Pacific Ocean.
Aspects of health and disease related to travel.
Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.
Virus diseases caused by the CORONAVIRUS genus. Some specifics include transmissible enteritis of turkeys (ENTERITIS, TRANSMISSIBLE, OF TURKEYS); FELINE INFECTIOUS PERITONITIS; and transmissible gastroenteritis of swine (GASTROENTERITIS, TRANSMISSIBLE, OF SWINE).
A species of CORONAVIRUS causing atypical respiratory disease (SEVERE ACUTE RESPIRATORY SYNDROME) in humans. The organism is believed to have first emerged in Guangdong Province, China, in 2002. The natural host is the Chinese horseshoe bat, RHINOLOPHUS sinicus.
A viral disorder characterized by high FEVER, dry COUGH, shortness of breath (DYSPNEA) or breathing difficulties, and atypical PNEUMONIA. A virus in the genus CORONAVIRUS is the suspected agent.

Retinoic acid stimulates the expression of 11beta-hydroxysteroid dehydrogenase type 2 in human choriocarcinoma JEG-3 cells. (1/1031)

The syncytiotrophoblasts of the human placenta express high levels of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), the enzyme responsible for the inactivation of glucocorticoids. It has been proposed that the placental 11beta-HSD2 serves as a barrier to protect the fetus from high levels of maternal cortisol. To examine the hypothesis that nutritional signals regulate the expression of 11beta-HSD2 in placental syncytiotrophoblasts, we investigated the effects of retinoic acids (RAs), the major metabolites of vitamin A, on the expression of 11beta-HSD2 using human choriocarcinoma JEG-3 cells as a model. This trophoblast-like cell line displays a number of functional similarities to the syncytiotrophoblast. Treatment for 24 h with all-trans RA (1-1000 nM) resulted in a dose-dependent increase in 11beta-HSD2 activity with a maximal effect (increase to 3-fold) at 100 nM. The effect of all-trans RA (100 nM) was also time-dependent in that the effect was detectable at 6 h and reached its maximum by 48 h. Similar increases in 11beta-HSD2 activity were observed when the cells were treated with 9-cis RA. Results from semi-quantitative reverse transcription-polymerase chain reaction demonstrated that there was a corresponding increase in 11beta-HSD2 mRNA after RA treatment. Moreover, treatment with actinomycin D (100 ng/ml) abrogated the increase in 11beta-HSD2 mRNA induced by RA, indicating an effect on transcription. In conclusion, the present study has demonstrated for the first time that RA, at physiological concentrations, induces 11beta-HSD2 gene expression and enzyme activity in JEG-3 cells. If this occurs in vivo, the present finding suggests that high expression of 11beta-HSD2 in the human placenta may be maintained, at least in part, by dietary intake of vitamin A.  (+info)

Onset of nucleolar and extranucleolar transcription and expression of fibrillarin in macaque embryos developing in vitro. (2/1031)

Specific aims were to characterize the onset of nucleolar and extranucleolar transcription and expression of the nucleolar protein fibrillarin during preimplantation development in vitro in macaque embryos using autoradiographic and immunocytochemical techniques. Autoradiography was performed on whole embryos cultured with [3H]uridine for assessment of nucleolar (rRNA) and extranucleolar (mRNA) transcription. Expression of fibrillarin was immunocytochemically assessed in whole embryos using a primary antibody against fibrillarin and a fluorescein isothiocyanate-conjugated secondary antibody. Extranucleolar incorporation of [3H]uridine was first detected in 2-cell embryos cultured 6-10 h with [3H]uridine. Culture with alpha-amanitin prevented incorporation of label in 2-cell embryos, and treatment with ribonuclease reduced the signal to background levels, indicating that [3H]uridine was incorporated into mRNA and not rRNA or DNA. Nucleolar incorporation of [3H]uridine was not evident in pronucleate-stage or 2- to 5-cell embryos, but it was detected in one 6-cell embryo and in all 8-cell to blastocyst-stage embryos. Fibrillarin was first expressed in some 6- to 7-cell embryos, but it was consistently expressed in all 8-cell embryos. Fibrillarin was localized to the perimeter of the nucleolar precursor bodies, forming a ring that completely encapsulated these structures. Fibrillarin was not expressed in 8- to 16-cell embryos cultured with alpha-amanitin, indicating that it is transcribed, rather than recruited, at the 8-cell stage. In conclusion, in in vitro-fertilized macaque embryos developing in vitro, extranucleolar synthesis of mRNA is initiated at the 2-cell stage while the onset of nucleolar transcription occurs at the 6- to 8-cell stage, coincident with expression of fibrillarin.  (+info)

Regulation of interleukin-8 expression by reduced oxygen pressure in human glioblastoma. (3/1031)

Oxygen deprivation is an important biological feature of tumor growth. We previously showed that in glioma, anoxia increases expression of IL-8, a chemokine and angiogenic factor. Here, we analysed for the first time the biochemical mechanisms inducing the IL-8 gene upon anoxia in glioma cells, and showed that they differ from those inducing the VEGF gene. Both genes are induced in biologically and genetically heterogenous glioblastoma cell lines (LN-229, LN-Z308, U87MG, T98G), whereas, in gliosarcoma cells (D247MG), only the VEGF gene is induced. The kinetics of IL-8 and VEGF mRNA inductions differ in these cells and reoxygenation experiments showed that the induction is due to the anoxic stress per se. Furthermore, in LN-229 and LN-Z308 cell lines actinomycin D, DRB and nuclear run-on experiments showed that anoxia stimulates increased transcription of both genes. Electromobility shift assays show increased protein binding to the AP-1 site on the IL-8 promoter following anoxia treatment. Finally, in situ hybridization on glioblastoma sections shows that the in vivo expression patterns of IL-8 and VEGF genes overlap, but are not identical. Since intratumoral augmentation of IL-8 and VEGF secretion, following microenvironmental decreases in oxygen pressure, may promote angiogenesis, further definition of these pathways is essential to appropriately target them for antitumoral therapy.  (+info)

Distribution of 5-chloromethylfluorescein diacetate staining during meiotic maturation and fertilization in vitro of mouse oocytes. (4/1031)

The aim of this confocal microscopy study was to determine whether the pattern of CellTracker Green 5-chloromethylfluorescein diacetate (CMFDA) staining changes during meiotic maturation and fertilization in vitro of mouse oocytes. At different times during meiotic maturation and fertilization, oocytes, zygotes and two-cell embryos were stained with CMFDA to demonstrate intracellular glutathione S-transferase activity. After washing in CMFDA-free medium, most oocytes, zygotes and embryos were stained with dihydroethidium (HE) to visualize DNA structures. Meiotic maturation and fertilization in vitro of mouse oocytes were associated with changes in the pattern of intracellular CMFDA staining. In particular, accumulations of CMFDA-positive membranes were observed around the nucleus of germinal vesicle (GV) oocytes, overlaying the sperm nucleus as well as overlaying the first mitotic spindle if this approached the plasma membrane. Staining of oocytes and zygotes with the probes 3,3'-dihexyloxacarbocyanine iodine [DiOC6(3)], which stains all the intracellular membranes, and rhodamine 123, which stains active mitochondria, demonstrated that the intracellular structures evidenced by CMFDA staining did not correspond to accumulations of mitochondria. Exposure of oocytes and zygotes to the microtubule-disrupting agent nocodazole or the actin-depolymerizing drug cytochalasin D revealed an autonomous microfilament-dependent transport and relocation of CMFDA-positive membranes during meiotic maturation and fertilization. Such a transport of CMFDA-positive membranes may be envisaged as a protective shield built to prevent damage to DNA from endogenous and exogenous mutagen metabolites.  (+info)

Concordant induction of cyclin E and p21cip1 in differentiated keratinocytes by the human papillomavirus E7 protein inhibits cellular and viral DNA synthesis. (5/1031)

Productive infections by human papillomaviruses (HPVs) occur only in differentiated keratinocytes in squamous epithelia in which the HPV E7 protein reactivates the host DNA replication machinery to support viral DNA replication. In a fraction of the differentiated keratinocytes, E7 also posttranscriptionally induces p21Cip1, which is distributed in a mutually exclusive manner with unscheduled cellular DNA synthesis. In this study, double immunofluorescence labeling unexpectedly revealed that E7 caused a concordant accumulation of both cyclin E and p21Cip1 to high levels in patient papillomas and in organotypic cultures of primary human keratinocytes. The induction of cyclin E is mutually exclusive with unscheduled cellular DNA synthesis or abundant viral DNA. These novel virus-host interactions in differentiated keratinocytes are in contrast to previous observations made in submerged proliferating cultures, in which HPV E7 induces cyclin E and overcomes p21Cip1 inhibition of S-phase entry. We propose that an appropriately timed induction of cyclin E/cyclin-dependent kinase 2 by HPV E7 in postmitotic cells enables S-phase reentry and HPV DNA amplification, whereas prematurely induced cyclin E stabilizes p21Cip1 protein, which then inhibits cyclin E/cyclin-dependent kinase 2. Consequently, cyclin E and p21Cip1 both fail to turn over, and DNA synthesis does not occur.  (+info)

Transcriptional regulation of interleukin-2 gene expression is impaired by copper deficiency in Jurkat human T lymphocytes. (6/1031)

Copper deficiency reduces secretion of the cytokine interleukin-2 (IL-2) by activated rodent splenocytes, human peripheral blood mononuclear cells and Jurkat cells, a human T lymphocyte cell line. Previous studies showed that low Cu status also decreased the level of IL-2 mRNA in activated Jurkat cells by 50%. Synthesis of this cytokine is regulated by alterations in transcription of the IL-2 gene and the stability of IL-2 mRNA. To determine if Cu status influenced promoter activity of the IL-2 gene, Jurkat cells were transfected with a luciferase reporter gene construct containing the entire 300 bp human IL-2 promoter/enhancer sequence. Cu deficiency was induced by incubating stably transfected cells with the Cu chelator 2,3,2-tetraamine for 35 h prior to activating cells with phytohemagglutinin-P and phorbol myristate acetate. Luciferase activity in lysates of Cu-deficient cells was approximately 50% lower in several multiclonal and clonal cell lines of stably transfected cells than in replicate cultures that were not exposed to chelator. The relative levels of endogenous IL-2 bioactivity and luciferase activity were highly correlated in the transfected cell lines. The chelator-mediated reduction in reporter gene activity was dose-dependent at levels of 5-40 micromol 2,3,2-tetraamine/L. The addition of a slight molar excess of Cu, but not Zn or Fe, to medium containing 2,3,2-tetraamine prevented the decline in luciferase activity. IL-2 mRNA stability in parental Jurkat cells was independent of Cu status. These data indicate that decreased cellular Cu attenuates IL-2 synthesis in T lymphocytes by inhibiting transcription of the IL-2 gene.  (+info)

Morphologic evaluation and actin filament distribution in porcine embryos produced in vitro and in vivo. (7/1031)

Porcine embryos produced in vitro have a small number of cells and low viability. The present study was conducted to examine the morphological characteristics and the relationship between actin filament organization and morphology of porcine embryos produced in vitro and in vivo. In vitro-derived embryos were produced by in vitro maturation, in vitro fertilization (IVF), and in vitro development. In vivo-derived embryos were collected from inseminated gilts on Days 2-6 after estrus. In experiment 1, in vitro-derived embryos (+info)

Filopodial adhesion does not predict growth cone steering events in vivo. (8/1031)

Migration of growth cones is in part mediated by adhesive interactions between filopodia and the extracellular environment, transmitting forces and signals necessary for pathfinding. To elucidate the role of substrate adhesivity in growth cone pathfinding, we developed an in vivo assay for measuring filopodial-substrate adhesivity using the well-characterized Ti pioneer neuron pathway of the embryonic grasshopper limb. Using time-lapse imaging and a combination of rhodamine-phalloidin injections and DiI labeling, we demonstrate that the filopodial retraction rate after treatment with cytochalasin D or elastase reflects the degree of filopodial-substrate adhesivity. Measurements of filopodial retraction rates along regions of known differing substrate adhesivities confirmed the use of this assay to examine filopodial-substrate adhesion during in vivo pathfinding events. We analyzed 359 filopodia from 22 Ti growth cones and found that there is no difference between the retraction rates of filopodia extending toward the correct target (on-axis) and filopodia extending away from the correct target (off-axis). These results indicate on-axis and off-axis filopodia have similar substrate adherence. Interestingly, we observed a 300% increase in the extension rates of on-axis filopodia during Ti growth cone turning events. Therefore, in addition to providing filopodia with important guidance information, regional cues are capable of modulating the filopodial extension rate. The homogeneity in filopodial retraction rates, even among these turning growth cones in which differential adhesivity might be expected to be greatest, strongly establishes that differential adhesion does not govern Ti pioneer neuron migration rate or pathfinding. We propose that the presence of local differences in receptor-mediated second messenger cascades and the resulting assembly of force-generating machinery may underlie the ability of filopodial contacts to regulate growth cone steering in vivo.  (+info)

Fatty acid synthesis inhibitors are a class of drugs that block the production of fatty acids in the body. Fatty acids are necessary for the normal functioning of the body, but an overproduction of certain types of fatty acids can contribute to the development of various medical conditions, such as obesity, diabetes, and cardiovascular disease.

Fatty acid synthesis inhibitors work by targeting enzymes involved in the synthesis of fatty acids, particularly fatty acid synthase (FAS). FAS is an enzyme that plays a key role in the production of palmitate, a saturated fatty acid that is a building block for other fatty acids. By inhibiting FAS, these drugs can reduce the amount of palmitate and other fatty acids produced in the body.

There are several types of fatty acid synthesis inhibitors, including:

1. Orlistat (Xenical, Alli): This drug works by blocking the action of lipases, enzymes that break down dietary fats in the gut. By preventing the absorption of dietary fats, orlistat can help reduce calorie intake and promote weight loss.
2. Tebufelone: This is a non-steroidal anti-inflammatory drug (NSAID) that has been shown to inhibit FAS and reduce the production of pro-inflammatory cytokines. It has been studied as a potential treatment for various inflammatory conditions, such as rheumatoid arthritis and psoriasis.
3. Cerulenin: This is a natural product that inhibits FAS and has been used in research to study the role of fatty acid synthesis in various biological processes.
4. C75: This is a synthetic compound that inhibits FAS and has been studied as a potential anti-cancer agent, as cancer cells often have increased rates of fatty acid synthesis.

It's important to note that while fatty acid synthesis inhibitors can be effective in reducing the production of certain types of fatty acids, they may also have side effects and potential risks. Therefore, it is essential to use these drugs under the supervision of a healthcare provider and to follow their instructions carefully.

Nucleic acid synthesis inhibitors are a class of antimicrobial, antiviral, or antitumor agents that block the synthesis of nucleic acids (DNA or RNA) by interfering with enzymes involved in their replication. These drugs can target various stages of nucleic acid synthesis, including DNA transcription, replication, and repair, as well as RNA transcription and processing.

Examples of nucleic acid synthesis inhibitors include:

1. Antibiotics like quinolones (e.g., ciprofloxacin), rifamycins (e.g., rifampin), and trimethoprim, which target bacterial DNA gyrase, RNA polymerase, or dihydrofolate reductase, respectively.
2. Antiviral drugs like reverse transcriptase inhibitors (e.g., zidovudine, lamivudine) and integrase strand transfer inhibitors (e.g., raltegravir), which target HIV replication by interfering with viral enzymes required for DNA synthesis.
3. Antitumor drugs like antimetabolites (e.g., methotrexate, 5-fluorouracil) and topoisomerase inhibitors (e.g., etoposide, doxorubicin), which interfere with DNA replication and repair in cancer cells.

These drugs have been widely used for treating various bacterial and viral infections, as well as cancers, due to their ability to selectively inhibit the growth of target cells without affecting normal cellular functions significantly. However, they may also cause side effects related to their mechanism of action or off-target effects on non-target cells.

Cerulenin is a fungal metabolite that inhibits the enzyme delta-9-desaturase, which is involved in fatty acid synthesis. This compound is often used in research to study the biology and function of fatty acid synthase and lipid metabolism. It has been investigated for its potential as an anti-cancer agent, but its clinical use is not approved due to its limited specificity and potential toxicity.

Nucleic acids are biological macromolecules composed of linear chains of nucleotides. They play crucial roles in the structure and function of cells, serving as the primary information-carrying molecules in all known forms of life. The two main types of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is responsible for storing genetic information in a stable form that can be passed down from generation to generation, while RNA plays a key role in translating the genetic code stored in DNA into functional proteins.

Each nucleotide consists of a sugar molecule, a phosphate group, and a nitrogenous base. The sugar in DNA is deoxyribose, while in RNA it is ribose. The nitrogenous bases found in both DNA and RNA include adenine (A), guanine (G), and cytosine (C). Thymine (T) is found in DNA, but uracil (U) takes its place in RNA. These nucleotides are linked together by phosphodiester bonds between the sugar of one nucleotide and the phosphate group of another, forming a long, helical structure with backbones made up of alternating sugar and phosphate groups.

The sequence of these nitrogenous bases along the nucleic acid chain encodes genetic information in the form of codons, which are sets of three consecutive bases that specify particular amino acids or signals for protein synthesis. This information is used to direct the synthesis of proteins through a process called transcription (converting DNA to RNA) and translation (converting RNA to protein).

In summary, nucleic acids are essential biomolecules composed of chains of nucleotides that store, transmit, and express genetic information in cells. They consist of two main types: DNA and RNA, which differ in their sugar type, nitrogenous bases, and functions.

"Enterobacter aerogenes" is a species of gram-negative, facultatively anaerobic, rod-shaped bacteria that are commonly found in the environment, including in soil, water, and vegetation. In medical contexts, E. aerogenes is often considered an opportunistic pathogen, meaning it can cause infection in individuals with compromised immune systems or underlying health conditions.

E. aerogenes is a member of the family Enterobacteriaceae and is closely related to other pathogens such as Klebsiella pneumoniae and Escherichia coli. It is known for its ability to produce large amounts of gas, including carbon dioxide and hydrogen sulfide, which can contribute to its virulence and make it difficult to identify using traditional biochemical tests.

E. aerogenes can cause a variety of infections, including urinary tract infections, pneumonia, bacteremia, and wound infections. It is often resistant to multiple antibiotics, which can make treatment challenging. In recent years, there has been an increase in the number of E. aerogenes isolates that are resistant to carbapenems, a class of antibiotics that are often used as a last resort for treating serious bacterial infections.

Uridine is a nucleoside that consists of a pyrimidine base (uracil) linked to a pentose sugar (ribose). It is a component of RNA, where it pairs with adenine. Uridine can also be found in various foods such as beer, broccoli, yeast, and meat. In the body, uridine can be synthesized from orotate or from the breakdown of RNA. It has several functions, including acting as a building block for RNA, contributing to energy metabolism, and regulating cell growth and differentiation. Uridine is also available as a dietary supplement and has been studied for its potential benefits in various health conditions.

RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.

Protein synthesis inhibitors are a class of medications or chemical substances that interfere with the process of protein synthesis in cells. Protein synthesis is the biological process by which cells create proteins, essential components for the structure, function, and regulation of tissues and organs. This process involves two main stages: transcription and translation.

Translation is the stage where the genetic information encoded in messenger RNA (mRNA) is translated into a specific sequence of amino acids, resulting in a protein molecule. Protein synthesis inhibitors work by targeting various components of the translation machinery, such as ribosomes, transfer RNAs (tRNAs), or translation factors, thereby preventing or disrupting the formation of new proteins.

These inhibitors have clinical applications in treating various conditions, including bacterial and viral infections, cancer, and autoimmune disorders. Some examples of protein synthesis inhibitors include:

1. Antibiotics: Certain antibiotics, like tetracyclines, macrolides, aminoglycosides, and chloramphenicol, target bacterial ribosomes and inhibit their ability to synthesize proteins, thereby killing or inhibiting the growth of bacteria.
2. Antiviral drugs: Protein synthesis inhibitors are used to treat viral infections by targeting various stages of the viral replication cycle, including protein synthesis. For example, ribavirin is an antiviral drug that can inhibit viral RNA-dependent RNA polymerase and mRNA capping, which are essential for viral protein synthesis.
3. Cancer therapeutics: Some chemotherapeutic agents target rapidly dividing cancer cells by interfering with their protein synthesis machinery. For instance, puromycin is an aminonucleoside antibiotic that can be incorporated into elongating polypeptide chains during translation, causing premature termination and inhibiting overall protein synthesis in cancer cells.
4. Immunosuppressive drugs: Protein synthesis inhibitors are also used as immunosuppressants to treat autoimmune disorders and prevent organ rejection after transplantation. For example, tacrolimus and cyclosporine bind to and inhibit the activity of calcineurin, a protein phosphatase that plays a crucial role in T-cell activation and cytokine production.

In summary, protein synthesis inhibitors are valuable tools for treating various diseases, including bacterial and viral infections, cancer, and autoimmune disorders. By targeting the protein synthesis machinery of pathogens or abnormal cells, these drugs can selectively inhibit their growth and proliferation while minimizing harm to normal cells.

Metabolism is the complex network of chemical reactions that occur within our bodies to maintain life. It involves two main types of processes: catabolism, which is the breaking down of molecules to release energy, and anabolism, which is the building up of molecules using energy. These reactions are necessary for the body to grow, reproduce, respond to environmental changes, and repair itself. Metabolism is a continuous process that occurs at the cellular level and is regulated by enzymes, hormones, and other signaling molecules. It is influenced by various factors such as age, genetics, diet, physical activity, and overall health status.

Thymidine is a pyrimidine nucleoside that consists of a thymine base linked to a deoxyribose sugar by a β-N1-glycosidic bond. It plays a crucial role in DNA replication and repair processes as one of the four nucleosides in DNA, along with adenosine, guanosine, and cytidine. Thymidine is also used in research and clinical settings for various purposes, such as studying DNA synthesis or as a component of antiviral and anticancer therapies.

Phosphorus isotopes are different forms of the element phosphorus that have different numbers of neutrons in their atomic nuclei, while the number of protons remains the same. The most common and stable isotope of phosphorus is 31P, which contains 15 protons and 16 neutrons. However, there are also several other isotopes of phosphorus that exist, including 32P and 33P, which are radioactive and have 15 protons and 17 or 18 neutrons, respectively. These radioactive isotopes are often used in medical research and treatment, such as in the form of radiopharmaceuticals to diagnose and treat various diseases.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Tritium is not a medical term, but it is a term used in the field of nuclear physics and chemistry. Tritium (symbol: T or 3H) is a radioactive isotope of hydrogen with two neutrons and one proton in its nucleus. It is also known as heavy hydrogen or superheavy hydrogen.

Tritium has a half-life of about 12.3 years, which means that it decays by emitting a low-energy beta particle (an electron) to become helium-3. Due to its radioactive nature and relatively short half-life, tritium is used in various applications, including nuclear weapons, fusion reactors, luminous paints, and medical research.

In the context of medicine, tritium may be used as a radioactive tracer in some scientific studies or medical research, but it is not a term commonly used to describe a medical condition or treatment.

Carbon isotopes are variants of the chemical element carbon that have different numbers of neutrons in their atomic nuclei. The most common and stable isotope of carbon is carbon-12 (^{12}C), which contains six protons and six neutrons. However, carbon can also come in other forms, known as isotopes, which contain different numbers of neutrons.

Carbon-13 (^{13}C) is a stable isotope of carbon that contains seven neutrons in its nucleus. It makes up about 1.1% of all carbon found on Earth and is used in various scientific applications, such as in tracing the metabolic pathways of organisms or in studying the age of fossilized materials.

Carbon-14 (^{14}C), also known as radiocarbon, is a radioactive isotope of carbon that contains eight neutrons in its nucleus. It is produced naturally in the atmosphere through the interaction of cosmic rays with nitrogen gas. Carbon-14 has a half-life of about 5,730 years, which makes it useful for dating organic materials, such as archaeological artifacts or fossils, up to around 60,000 years old.

Carbon isotopes are important in many scientific fields, including geology, biology, and medicine, and are used in a variety of applications, from studying the Earth's climate history to diagnosing medical conditions.

Bacterial RNA refers to the genetic material present in bacteria that is composed of ribonucleic acid (RNA). Unlike higher organisms, bacteria contain a single circular chromosome made up of DNA, along with smaller circular pieces of DNA called plasmids. These bacterial genetic materials contain the information necessary for the growth and reproduction of the organism.

Bacterial RNA can be divided into three main categories: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information copied from DNA, which is then translated into proteins by the rRNA and tRNA molecules. rRNA is a structural component of the ribosome, where protein synthesis occurs, while tRNA acts as an adapter that brings amino acids to the ribosome during protein synthesis.

Bacterial RNA plays a crucial role in various cellular processes, including gene expression, protein synthesis, and regulation of metabolic pathways. Understanding the structure and function of bacterial RNA is essential for developing new antibiotics and other therapeutic strategies to combat bacterial infections.

Peptide Nucleic Acids (PNAs) are synthetic, artificially produced molecules that have a structure similar to both peptides (short chains of amino acids) and nucleic acids (DNA and RNA). They consist of repeating units called "monomers" made up of a pseudopeptide backbone with nucleobases attached. The backbone is composed of N-(2-aminoethyl)glycine units, which replace the sugar-phosphate backbone found in natural nucleic acids.

PNAs are known for their high binding affinity and sequence-specific recognition of DNA and RNA molecules. They can form stable complexes with complementary DNA or RNA strands through Watson-Crick base pairing, even under conditions where normal nucleic acid hybridization is poor. This property makes them valuable tools in molecular biology for various applications such as:

1. Gene regulation and silencing
2. Antisense and antigen technologies
3. Diagnostics and biosensors
4. Study of protein-DNA interactions
5. DNA repair and mutation analysis

However, it is important to note that Peptide Nucleic Acids are not naturally occurring molecules; they are entirely synthetic and must be produced in a laboratory setting.

Uracil is not a medical term, but it is a biological molecule. Medically or biologically, uracil can be defined as one of the four nucleobases in the nucleic acid of RNA (ribonucleic acid) that is linked to a ribose sugar by an N-glycosidic bond. It forms base pairs with adenine in double-stranded RNA and DNA. Uracil is a pyrimidine derivative, similar to thymine found in DNA, but it lacks the methyl group (-CH3) that thymine has at the 5 position of its ring.

Hypoxanthine is not a medical condition but a purine base that is a component of many organic compounds, including nucleotides and nucleic acids, which are the building blocks of DNA and RNA. In the body, hypoxanthine is produced as a byproduct of normal cellular metabolism and is converted to xanthine and then uric acid, which is excreted in the urine.

However, abnormally high levels of hypoxanthine in the body can indicate tissue damage or disease. For example, during intense exercise or hypoxia (low oxygen levels), cells may break down ATP (adenosine triphosphate) rapidly, releasing large amounts of hypoxanthine. Similarly, in some genetic disorders such as Lesch-Nyhan syndrome, there is an accumulation of hypoxanthine due to a deficiency of the enzyme that converts it to xanthine. High levels of hypoxanthine can lead to the formation of kidney stones and other complications.

Cycloheximide is an antibiotic that is primarily used in laboratory settings to inhibit protein synthesis in eukaryotic cells. It is derived from the actinobacteria species Streptomyces griseus. In medical terms, it is not used as a therapeutic drug in humans due to its significant side effects, including liver toxicity and potential neurotoxicity. However, it remains a valuable tool in research for studying protein function and cellular processes.

The antibiotic works by binding to the 60S subunit of the ribosome, thereby preventing the transfer RNA (tRNA) from delivering amino acids to the growing polypeptide chain during translation. This inhibition of protein synthesis can be lethal to cells, making cycloheximide a useful tool in studying cellular responses to protein depletion or misregulation.

In summary, while cycloheximide has significant research applications due to its ability to inhibit protein synthesis in eukaryotic cells, it is not used as a therapeutic drug in humans because of its toxic side effects.

Adenine is a purine nucleotide base that is a fundamental component of DNA and RNA, the genetic material of living organisms. In DNA, adenine pairs with thymine via double hydrogen bonds, while in RNA, it pairs with uracil. Adenine is essential for the structure and function of nucleic acids, as well as for energy transfer reactions in cells through its role in the formation of adenosine triphosphate (ATP), the primary energy currency of the cell.

Protein biosynthesis is the process by which cells generate new proteins. It involves two major steps: transcription and translation. Transcription is the process of creating a complementary RNA copy of a sequence of DNA. This RNA copy, or messenger RNA (mRNA), carries the genetic information to the site of protein synthesis, the ribosome. During translation, the mRNA is read by transfer RNA (tRNA) molecules, which bring specific amino acids to the ribosome based on the sequence of nucleotides in the mRNA. The ribosome then links these amino acids together in the correct order to form a polypeptide chain, which may then fold into a functional protein. Protein biosynthesis is essential for the growth and maintenance of all living organisms.

Purines are heterocyclic aromatic organic compounds that consist of a pyrimidine ring fused to an imidazole ring. They are fundamental components of nucleotides, which are the building blocks of DNA and RNA. In the body, purines can be synthesized endogenously or obtained through dietary sources such as meat, seafood, and certain vegetables.

Once purines are metabolized, they are broken down into uric acid, which is excreted by the kidneys. Elevated levels of uric acid in the body can lead to the formation of uric acid crystals, resulting in conditions such as gout or kidney stones. Therefore, maintaining a balanced intake of purine-rich foods and ensuring proper kidney function are essential for overall health.

Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.

Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.

Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.

Anisomycin is an antibiotic derived from the bacterium Streptomyces griseolus. It is a potent inhibitor of protein synthesis and has been found to have antitumor, antiviral, and immunosuppressive properties. In medicine, it has been used experimentally in the treatment of some types of cancer, but its use is limited due to its significant side effects, including neurotoxicity.

In a medical or scientific context, 'anisomycin' refers specifically to this antibiotic compound and not to any general concept related to aniso- (meaning "unequal" or "asymmetrical") or -mycin (suffix indicating a bacterial antibiotic).

Research, in the context of medicine, is a systematic and rigorous process of collecting, analyzing, and interpreting information in order to increase our understanding, develop new knowledge, or evaluate current practices and interventions. It can involve various methodologies such as observational studies, experiments, surveys, or literature reviews. The goal of medical research is to advance health care by identifying new treatments, improving diagnostic techniques, and developing prevention strategies. Medical research is typically conducted by teams of researchers including clinicians, scientists, and other healthcare professionals. It is subject to ethical guidelines and regulations to ensure that it is conducted responsibly and with the best interests of patients in mind.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

DNA replication is the biological process by which DNA makes an identical copy of itself during cell division. It is a fundamental mechanism that allows genetic information to be passed down from one generation of cells to the next. During DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. This results in the creation of two identical DNA molecules. The enzymes responsible for DNA replication include helicase, which unwinds the double helix, and polymerase, which adds nucleotides to the growing strands.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Fatty acids are carboxylic acids with a long aliphatic chain, which are important components of lipids and are widely distributed in living organisms. They can be classified based on the length of their carbon chain, saturation level (presence or absence of double bonds), and other structural features.

The two main types of fatty acids are:

1. Saturated fatty acids: These have no double bonds in their carbon chain and are typically solid at room temperature. Examples include palmitic acid (C16:0) and stearic acid (C18:0).
2. Unsaturated fatty acids: These contain one or more double bonds in their carbon chain and can be further classified into monounsaturated (one double bond) and polyunsaturated (two or more double bonds) fatty acids. Examples of unsaturated fatty acids include oleic acid (C18:1, monounsaturated), linoleic acid (C18:2, polyunsaturated), and alpha-linolenic acid (C18:3, polyunsaturated).

Fatty acids play crucial roles in various biological processes, such as energy storage, membrane structure, and cell signaling. Some essential fatty acids cannot be synthesized by the human body and must be obtained through dietary sources.

Emetine is a medication that is derived from the plant ipecacuanha. It is an alkaloid that has been used in the treatment of certain parasitic infections, particularly those caused by intestinal amoebae. Emetine works by inhibiting protein synthesis in the parasites, which helps to eliminate them from the body.

Emetine is administered orally or by injection and is typically used as a last resort when other treatments have failed. It can cause significant side effects, including nausea, vomiting, and diarrhea, as well as more serious complications such as heart rhythm abnormalities and muscle weakness. As a result, its use is generally restricted to cases where the benefits of treatment outweigh the risks.

It's important to note that emetine should only be used under the close supervision of a healthcare provider, and its use carries a number of precautions and contraindications. It is not recommended for use in pregnant women or people with certain medical conditions, such as heart disease or kidney disease.

Puromycin is an antibiotic and antiviral protein synthesis inhibitor. It works by being incorporated into the growing peptide chain during translation, causing premature termination and release of the incomplete polypeptide. This results in the inhibition of protein synthesis and ultimately leads to cell death. In research, puromycin is often used as a selective agent in cell culture to kill cells that have not been transfected with a plasmid containing a resistance gene for puromycin.

Dactinomycin is an antineoplastic antibiotic, which means it is used to treat cancer. It is specifically used to treat certain types of testicular cancer, Wilms' tumor (a type of kidney cancer that occurs in children), and some gestational trophoblastic tumors (a type of tumor that can develop in the uterus after pregnancy). Dactinomycin works by interfering with the DNA in cancer cells, which prevents them from dividing and growing. It is often used in combination with other chemotherapy drugs as part of a treatment regimen.

Dactinomycin is administered intravenously (through an IV) and its use is usually limited to hospitals or specialized cancer treatment centers due to the need for careful monitoring during administration. Common side effects include nausea, vomiting, and hair loss. More serious side effects can include bone marrow suppression, which can lead to an increased risk of infection, and tissue damage at the site where the drug is injected. Dactinomycin can also cause severe allergic reactions in some people.

It's important to note that dactinomycin should only be used under the supervision of a qualified healthcare professional, as its use requires careful monitoring and management of potential side effects.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

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.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Nucleic acid probes are specialized single-stranded DNA or RNA molecules that are used in molecular biology to identify and detect specific nucleic acid sequences, such as genes or fragments of DNA or RNA. These probes are typically labeled with a marker, such as a radioactive isotope or a fluorescent dye, which allows them to be detected and visualized.

Nucleic acid probes work by binding or "hybridizing" to their complementary target sequence through base-pairing interactions between the nucleotides that make up the probe and the target. This specificity of hybridization allows for the detection and identification of specific sequences within a complex mixture of nucleic acids, such as those found in a sample of DNA or RNA from a biological specimen.

Nucleic acid probes are used in a variety of applications, including gene expression analysis, genetic mapping, diagnosis of genetic disorders, and detection of pathogens, among others. They are an essential tool in modern molecular biology research and have contributed significantly to our understanding of genetics and disease.

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.

Nucleic acid hybridization is a process in molecular biology where two single-stranded nucleic acids (DNA, RNA) with complementary sequences pair together to form a double-stranded molecule through hydrogen bonding. The strands can be from the same type of nucleic acid or different types (i.e., DNA-RNA or DNA-cDNA). This process is commonly used in various laboratory techniques, such as Southern blotting, Northern blotting, polymerase chain reaction (PCR), and microarray analysis, to detect, isolate, and analyze specific nucleic acid sequences. The hybridization temperature and conditions are critical to ensure the specificity of the interaction between the two strands.

Nucleic acid amplification techniques (NAATs) are medical laboratory methods used to increase the number of copies of a specific DNA or RNA sequence. These techniques are widely used in molecular biology and diagnostics, including the detection and diagnosis of infectious diseases, genetic disorders, and cancer.

The most commonly used NAAT is the polymerase chain reaction (PCR), which involves repeated cycles of heating and cooling to separate and replicate DNA strands. Other NAATs include loop-mediated isothermal amplification (LAMP), nucleic acid sequence-based amplification (NASBA), and transcription-mediated amplification (TMA).

NAATs offer several advantages over traditional culture methods for detecting pathogens, including faster turnaround times, increased sensitivity and specificity, and the ability to detect viable but non-culturable organisms. However, they also require specialized equipment and trained personnel, and there is a risk of contamination and false positive results if proper precautions are not taken.

Bile acids and salts are naturally occurring steroidal compounds that play a crucial role in the digestion and absorption of lipids (fats) in the body. They are produced in the liver from cholesterol and then conjugated with glycine or taurine to form bile acids, which are subsequently converted into bile salts by the addition of a sodium or potassium ion.

Bile acids and salts are stored in the gallbladder and released into the small intestine during digestion, where they help emulsify fats, allowing them to be broken down into smaller molecules that can be absorbed by the body. They also aid in the elimination of waste products from the liver and help regulate cholesterol metabolism.

Abnormalities in bile acid synthesis or transport can lead to various medical conditions, such as cholestatic liver diseases, gallstones, and diarrhea. Therefore, understanding the role of bile acids and salts in the body is essential for diagnosing and treating these disorders.

Fatty acid synthases (FAS) are a group of enzymes that are responsible for the synthesis of fatty acids in the body. They catalyze a series of reactions that convert acetyl-CoA and malonyl-CoA into longer chain fatty acids, which are then used for various purposes such as energy storage or membrane formation.

The human genome encodes two types of FAS: type I and type II. Type I FAS is a large multifunctional enzyme complex found in the cytoplasm of cells, while type II FAS consists of individual enzymes located in the mitochondria. Both types of FAS play important roles in lipid metabolism, but their regulation and expression differ depending on the tissue and physiological conditions.

Inhibition of FAS has been explored as a potential therapeutic strategy for various diseases, including cancer, obesity, and metabolic disorders. However, more research is needed to fully understand the complex mechanisms regulating FAS activity and its role in human health and disease.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

A coronavirus is a type of virus that causes respiratory illnesses, such as the common cold, and more severe diseases including Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). These viruses are typically spread through close contact with an infected person when they cough or sneeze. They can also spread by touching a surface or object that has the virus on it and then touching your own mouth, nose, or eyes.

Coronaviruses are named for the crown-like spikes on their surface. They are zoonotic, meaning they can be transmitted between animals and people. Common signs of infection include fever, cough, and shortness of breath. In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure, and even death.

One of the most recently discovered coronaviruses is SARS-CoV-2, which causes the disease COVID-19. This virus was first identified in Wuhan, China in late 2019 and has since spread to become a global pandemic.

I am not aware of a specific medical definition for the term "China." Generally, it is used to refer to:

1. The People's Republic of China (PRC), which is a country in East Asia. It is the most populous country in the world and the fourth largest by geographical area. Its capital city is Beijing.
2. In a historical context, "China" was used to refer to various dynasties and empires that existed in East Asia over thousands of years. The term "Middle Kingdom" or "Zhongguo" (中国) has been used by the Chinese people to refer to their country for centuries.
3. In a more general sense, "China" can also be used to describe products or goods that originate from or are associated with the People's Republic of China.

If you have a specific context in which you encountered the term "China" related to medicine, please provide it so I can give a more accurate response.

I'm sorry for any confusion, but "travel" is not a term that has a specific medical definition. In general, travel refers to the act of moving or journeying from one place to another, often over long distances. However, in a medical context, it might refer to the recommendation that individuals with certain medical conditions or those who are immunocompromised avoid traveling to areas where they may be at increased risk of exposure to infectious diseases. It's always best to check with a healthcare professional for advice related to specific medical situations and travel.

A disease outbreak is defined as the occurrence of cases of a disease in excess of what would normally be expected in a given time and place. It may affect a small and localized group or a large number of people spread over a wide area, even internationally. An outbreak may be caused by a new agent, a change in the agent's virulence or host susceptibility, or an increase in the size or density of the host population.

Outbreaks can have significant public health and economic impacts, and require prompt investigation and control measures to prevent further spread of the disease. The investigation typically involves identifying the source of the outbreak, determining the mode of transmission, and implementing measures to interrupt the chain of infection. This may include vaccination, isolation or quarantine, and education of the public about the risks and prevention strategies.

Examples of disease outbreaks include foodborne illnesses linked to contaminated food or water, respiratory infections spread through coughing and sneezing, and mosquito-borne diseases such as Zika virus and West Nile virus. Outbreaks can also occur in healthcare settings, such as hospitals and nursing homes, where vulnerable populations may be at increased risk of infection.

Coronaviruses are a large family of viruses that can cause illnesses ranging from the common cold to more severe diseases such as pneumonia. The name "coronavirus" comes from the Latin word "corona," which means crown or halo, reflecting the distinctive appearance of the virus particles under electron microscopy, which have a crown-like structure due to the presence of spike proteins on their surface.

Coronaviruses are zoonotic, meaning they can be transmitted between animals and humans. Some coronaviruses are endemic in certain animal populations and occasionally jump to humans, causing outbreaks of new diseases. This is what happened with Severe Acute Respiratory Syndrome (SARS) in 2002-2003, Middle East Respiratory Syndrome (MERS) in 2012, and the most recent Coronavirus Disease 2019 (COVID-19), caused by SARS-CoV-2.

Coronavirus infections typically cause respiratory symptoms such as cough, shortness of breath, and fever. In severe cases, they can lead to pneumonia, acute respiratory distress syndrome (ARDS), and even death, especially in older adults or people with underlying medical conditions. Other symptoms may include fatigue, muscle aches, headache, sore throat, and gastrointestinal issues such as nausea, vomiting, and diarrhea.

Preventive measures for coronavirus infections include frequent hand washing, wearing face masks, practicing social distancing, avoiding close contact with sick individuals, and covering the mouth and nose when coughing or sneezing. There are currently vaccines available to prevent COVID-19, which have been shown to be highly effective in preventing severe illness, hospitalization, and death from the disease.

Severe Acute Respiratory Syndrome (SARS) is a viral respiratory illness caused by the SARS coronavirus (SARS-CoV). This virus is a member of the Coronaviridae family and is thought to be transmitted most readily through close person-to-person contact via respiratory droplets produced when an infected person coughs or sneezes.

The SARS outbreak began in southern China in 2002 and spread to several other countries before it was contained. The illness causes symptoms such as fever, chills, and body aches, which progress to a dry cough and sometimes pneumonia. Some people also report diarrhea. In severe cases, the illness can cause respiratory failure or death.

It's important to note that SARS is not currently a global health concern, as there have been no known cases since 2004. However, it remains a significant example of how quickly and widely a new infectious disease can spread in today's interconnected world.

Severe Acute Respiratory Syndrome (SARS) is a viral respiratory illness characterized by fever, cough, shortness of breath, and sometimes severe pneumonia. It is caused by the SARS coronavirus (SARS-CoV).

The syndrome is considered severe due to its potential to cause rapid spread in communities and healthcare settings, and for its high case fatality rate. In the global outbreak of 2002-2003, approximately 8,000 people were infected and nearly 800 died. Since then, no large outbreaks have been reported, although there have been isolated cases linked to laboratory accidents or animal exposures.

SARS is transmitted through close contact with an infected person's respiratory droplets, such as when they cough or sneeze. It can also be spread by touching a surface contaminated with the virus and then touching the mouth, nose, or eyes. Healthcare workers and others in close contact with infected individuals are at higher risk of infection.

Preventive measures include good personal hygiene, such as frequent handwashing, wearing masks and other protective equipment when in close contact with infected individuals, and practicing respiratory etiquette (covering the mouth and nose when coughing or sneezing). Infected individuals should be isolated and receive appropriate medical care to help manage their symptoms and prevent transmission to others.

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