Deoxyribonuclease HpaII
Deoxyribonuclease I
Methylation
DNA
Methyl Green
DNA Restriction Enzymes
5-Methylcytosine
Endodeoxyribonucleases
Haemophilus
Deoxyribonucleases, Type II Site-Specific
Phenolphthaleins
Exonucleases
Base Sequence
Endonucleases
Phosphorus Isotopes
Celosia
Expectorants
In vivo nuclease hypersensitivity studies reveal multiple sites of parental origin-dependent differential chromatin conformation in the 150 kb SNRPN transcription unit. (1/177)
Human chromosome region 15q11-q13 contains a cluster of oppositely imprinted genes. Loss of the paternal or the maternal alleles by deletion of the region or by uniparental disomy 15 results in Prader-Willi syndrome (PWS) or Angelman syndrome (AS), respectively. Hence, the two phenotypically distinct neurodevelopmental disorders are caused by the lack of products of imprinted genes. Subsets of PWS and AS patients exhibit 'imprinting mutations', such as small microdeletions within the 5' region of the small nuclear ribonucleoprotein polypeptide N ( SNRPN ) transcription unit which affect the transcriptional activity and methylation status of distant imprinted genes throughout 15q11-q13 in cis. To elucidate the mechanism of these long-range effects, we have analyzed the chromatin structure of the 150 kb SNRPN transcription unit for DNase I- and Msp I-hypersensitive sites. By using an in vivo approach on lymphoblastoid cell lines from PWS and AS individuals, we discovered that the SNRPN exon 1 is flanked by prominent hypersensitive sites on the paternal allele, but is completely inaccessible to nucleases on the maternal allele. In contrast, we identified several regions of increased nuclease hypersensitivity on the maternal allele, one of which coincides with the AS minimal microdeletion region and another lies in intron 1 immediately downstream of the paternal-specific hypersensitive sites. At several sites, parental origin-specific nuclease hypersensitivity was found to be correlated with hypermethylation on the allele contributed by the other parent. The differential parental origin-dependent chromatin conformations might govern access of regulatory protein complexes and/or RNAs which could mediate interaction of the region with other genes. (+info)The relationship between DNA methylation and chromosome imprinting in the coccid Planococcus citri. (2/177)
The phenomenon of chromosome, or genomic, imprinting indicates the relevance of parental origin in determining functional differences between alleles, homologous chromosomes, or haploid sets. In mealybug males (Homoptera, Coccoidea), the haploid set of paternal origin undergoes heterochromatization at midcleavage and remains so in most of the tissues. This different behavior of the two haploid sets, which depends on their parental origin, represents one of the most striking examples of chromosome imprinting. In mammals, DNA methylation has been postulated as a possible molecular mechanism to differentially imprint DNA sequences during spermatogenesis or oogenesis. In the present article we addressed the role of DNA methylation in the imprinting of whole haploid sets as it occurs in Coccids. We investigated the DNA methylation patterns at both the molecular and chromosomal level in the mealybug Planococcus citri. We found that in both males and females the paternally derived haploid set is hypomethylated with respect to the maternally derived one. Therefore, in males, it is the paternally derived hypomethylated haploid set that is heterochromatized. Our data suggest that the two haploid sets are imprinted by parent-of-origin-specific DNA methylation with no correlation with the known gene-silencing properties of this base modification. (+info)Specific methylation events contribute to the transcriptional repression of the mouse tissue inhibitor of metalloproteinases-3 gene in neoplastic cells. (3/177)
The tissue inhibitor of metalloproteinases-3 (TIMP-3) gene is specifically down-regulated in neoplastic cells of the mouse JB6 progression model, suggesting a role for TIMP-3 inactivation in neoplastic progression. On the basis of 5-azacytidine reversal, the mechanism for this down-regulation appears to involve changes in the methylation state of the TIMP-3 promoter. Although total genomic methylation levels are comparable, specific differences in the methylation of the TIMP-3 promoter were observed between preneoplastic and neoplastic JB6 cells at three Hpall sites, with preneoplastic cells being less methylated. Expression of antisense methyltransferase in a neoplastic JB6 variant known to be hypermethylated in TIMP-3 resulted in reactivation of the endogenous TIMP-3 gene and restoration of hypomethylated status to the three implicated Hpall sites. Thus, hypermethylation at specific sequences in the TIMP-3 promoter appears to contribute to the silencing of the gene in neoplastic cells. (+info)Packaging of DNA by shell crosslinked nanoparticles. (4/177)
We demonstrate compaction of DNA with nanoscale biomimetic constructs which are robust synthetic analogs of globular proteins. These constructs are approximately 15 nm in diameter, shell crosslinked knedel-like (SCKs) nanoparticles, which are prepared by covalent stabilization of amphiphilic di-block co-polymer micelles, self-assembled in an aqueous solution. This synthetic approach yields size-controlled nanoparticles of persistent shape and containing positively charged functional groups at and near the particle surface. Such properties allow SCKs to bind with DNA through electrostatic interactions and facilitate reduction of the DNA hydrodynamic diameter through reversible compaction. Compaction of DNA by SCKs was evident in dynamic light scattering experiments and was directly observed by in situ atomic force microscopy. Moreover, enzymatic digestion of the DNA plasmid (pBR322, 4361 bp) by Eco RI was inhibited at low SCK:DNA ratios and prevented when [le]60 DNA bp were bound per SCK. Digestion by Msp I in the presence of SCKs resulted in longer DNA fragments, indicating that not all enzyme cleavage sites were accessible within the DNA/SCK aggregates. These results have implications for the development of vehicles for successful gene therapy applications. (+info)Tissue and site-specific methylation correlates with expression of the mouse lactoferrin gene. (5/177)
We have previously examined the regulatory region of the mouse lactoferrin gene and have identified sequences essential for basal and hormonally induced expression. In this study, we explore the relationship between the methylation state of the mouse lactoferrin gene promoter and its expression in selected mouse tissues. In a transient expression system, transcriptional activity was blocked after in vitro methylation of the regulatory region of the mouse lactoferrin gene. In addition, the in vivo methylation state of three promoter region sites was assessed using Southern blot analysis of DNA digested with methylation-insensitive and -sensitive restriction enzymes. The results showed that site -455, upstream of the mouse lactoferrin estrogen response module, was highly unmethylated in DNA from both hormone-treated and -untreated mouse lung, liver, and spleen tissues. Also, in both treated and untreated samples, the -54 site is uniquely highly unmethylated in liver DNA, while the -22 site is unmethylated in spleen DNA. Northern blot analysis showed lactoferrin expression in tissues that were unmethylated at a minimum of two sites. These results show that the alteration of the methylation status of the three sites are tissue-specific and are associated with constitutive expression of lactoferrin. (+info)PCR detection, characterization, and distribution of virulence genes in Aeromonas spp. (6/177)
We found 73.1 to 96.9% similarity by aligning the cytolytic enterotoxin gene of Aeromonas hydrophila SSU (AHCYTOEN; GenBank accession no. M84709) against aerolysin genes of Aeromonas spp., suggesting the possibility of selecting common primers. Identities of 90 to 100% were found among the eight selected primers from those genes. Amplicons obtained from Aeromonas sp. reference strains by using specific primers for each gene or a cocktail of primers were 232 bp long. Of hybridization group 4/5A/5B (HG4/5A/5B), HG9, and HG12 or non-Aeromonas reference strains, none were positive. PCR-restriction fragment length polymorphism (PCR-RFLP) with HpaII yielded three types of patterns. PCR-RFLP 1 contained two fragments (66 and 166 bp) found in HG6, HG7, HG8, HG10, and HG11. PCR-RFLP 2 contained three fragments (18, 66, and 148 bp) found in HG1, HG2, HG3, and HG11. PCR-RFLP 3, with four fragments (7, 20, 66, and 139 bp), was observed only in HG13. PCR-amplicon sequence analysis (PCR-ASA) revealed three main types. PCR-ASA 1 had 76 to 78% homology with AHCYTOEN and included strains in HG6, HG7, HG8, HG10, and HG11. PCR-ASA 2, with 82% homology, was found only in HG13. PCR-ASA 3, with 91 to 99% homology, contained the strains in HG1, HG2, HG3, and HG11. This method indicated that 37 (61%) of the 61 reference strains were positive with the primer cocktail master mixture, and 34 (58%) of 59 environmental isolates, 93 (66%) of 141 food isolates, and 100 (67%) of 150 clinical isolates from around the world carried a virulence factor when primers AHCF1 and AHCR1 were used. In conclusion, this PCR-based method is rapid, sensitive, and specific for the detection of virulence factors of Aeromonas spp. It overcomes the handicap of time-consuming biochemical and other DNA-based methods. (+info)Relaxation of IGF2 imprinting in Wilms tumours associated with specific changes in IGF2 methylation. (7/177)
Relaxation of IGF2 imprinting occurs in Wilms tumours and many other cancers, but the mechanism of loss of imprinting (LOI) remains unknown. To investigate the role of altered DNA methylation in LOI, we examined the pattern of methylation of the human insulin-IGF2 region in Wilms tumours and the normal kidney. The analysis included regions homologous to three 'differentially methylated regions' of the mouse Igf2 gene (dmrs 0, 1 and 2). In tumours displaying normal IGF2 imprinting, and in the normal kidney, maternal allele-specific DNA methylation was identified spanning exons 2 and 3. This region is homologous to dmr 0, a site of maternal-specific differential methylation in the mouse. In Wilms tumours with relaxed imprinting or 11p15.5 LOH this region was unmethylated. No other differential methylation was identified. In particular, two sites of paternal methylation in the mouse (dmrs 1 and 2), and all three imprinted IGF2 promoters were not methylated in the kidney or in Wilms tumours. We postulate that LOI in Wilms tumours is associated with loss of maternal allele-specific methylation from a region located upstream of the imprinted IGF2 promoters. This region may contain cis acting sequences that coordinately influence imprinting. (+info)Restriction endonuclease analysis using Hhal and Hpall to discriminate among group B Pasteurella multocida associated with haemorrhagic septicaemia. (8/177)
The purpose of this study was to improve and standardise restriction endonuclease analysis (REA) for discriminating isolates of serogroup B Pasteurella multocida associated with haemorrhagic septicaemia in wild and domestic animals and to create a reference database that can be used for epidemiological studies. Two techniques for extraction and isolation of chromosomal DNA were compared, a DNAzol method and an enzymic lysis followed by a two-phase partition method. No differences were observed between DNA fingerprint profiles with either technique; however, the former technique was faster and easier to perform. P. multocida isolated from different animals in different countries representing serotypes B:2, B:3, B:3,4 and B:4 were subjected to REA with HhaI and HpaII endonucleases. Forty-eight fingerprint profiles were distinguished among 222 isolates when only HhaI was used. By combining the data from REA with HhaI and HpaII used separately, 88 different groups could be distinguished among the same isolates. Following digestion with HhaI and electrophoresis, the DNA of all serotype B:2 isolates produced fingerprint profiles characterised by two trailing bands at approximately 8.4-7.1 kb which have not been observed in any other serotypes of P. multocida. Passage of three serotype B:2 isolates on laboratory media or two serotype B:2 isolates through mice did not result in a change of DNA fingerprint profile detectable by REA. The findings with 59 isolates from Sri Lanka showed that REA was highly discriminative in determining the genetic diversity of serotype B:2 P. multocida in an area where haemorrhagic septicaemia is endemic. (+info)Deoxyribonuclease HpaII, also known as HpaII endonuclease or simply HpaII, is an enzyme that cleaves double-stranded DNA at the recognition site 5'-CCGG-3'. It is a type of restriction endonuclease that is isolated from the bacterium Haemophilus parainfluenzae. The 'H' and the 'pa' in HpaII stand for Haemophilus parainfluenzae, and the Roman numeral II indicates that it was the second such enzyme to be discovered from this bacterial species.
The HpaII enzyme cuts the DNA strand between the two Gs in the recognition site, leaving a 5'-overhang of two unpaired cytosines on the 3'-end of each cleaved strand. This specificity makes it useful for various molecular biology techniques, such as genetic fingerprinting, genome mapping, and DNA sequencing.
It is worth noting that HpaII is sensitive to methylation at the internal cytosine residue within its recognition site. If the inner cytosine in the 5'-CCGG-3' sequence is methylated (i.e., 5-methylcytosine), HpaII will not cut the DNA at that site, which can be exploited for epigenetic studies and DNA methylation analysis.
Deoxyribonucleases (DNases) are a group of enzymes that cleave, or cut, the phosphodiester bonds in the backbone of deoxyribonucleic acid (DNA) molecules. DNases are classified based on their mechanism of action into two main categories: double-stranded DNases and single-stranded DNases.
Double-stranded DNases cleave both strands of the DNA duplex, while single-stranded DNases cleave only one strand. These enzymes play important roles in various biological processes, such as DNA replication, repair, recombination, and degradation. They are also used in research and clinical settings for applications such as DNA fragmentation analysis, DNA sequencing, and treatment of cystic fibrosis.
It's worth noting that there are many different types of DNases with varying specificities and activities, and the medical definition may vary depending on the context.
Deoxyribonuclease I (DNase I) is an enzyme that cleaves the phosphodiester bonds in the DNA molecule, breaking it down into smaller pieces. It is also known as DNase A or bovine pancreatic deoxyribonuclease. This enzyme specifically hydrolyzes the internucleotide linkages of DNA by cleaving the phosphodiester bond between the 3'-hydroxyl group of one deoxyribose sugar and the phosphate group of another, leaving 3'-phosphomononucleotides as products.
DNase I plays a crucial role in various biological processes, including DNA degradation during apoptosis (programmed cell death), DNA repair, and host defense against pathogens by breaking down extracellular DNA from invading microorganisms or damaged cells. It is widely used in molecular biology research for applications such as DNA isolation, removing contaminating DNA from RNA samples, and generating defined DNA fragments for cloning purposes. DNase I can be found in various sources, including bovine pancreas, human tears, and bacterial cultures.
DNA cytosine methylases are a type of enzyme that catalyze the transfer of a methyl group (-CH3) to the carbon-5 position of the cytosine ring in DNA, forming 5-methylcytosine. This process is known as DNA methylation and plays an important role in regulating gene expression, genomic imprinting, X-chromosome inactivation, and suppression of transposable elements in eukaryotic organisms.
In mammals, the most well-studied DNA cytosine methylases are members of the DNMT (DNA methyltransferase) family, including DNMT1, DNMT3A, and DNMT3B. DNMT1 is primarily responsible for maintaining existing methylation patterns during DNA replication, while DNMT3A and DNMT3B are involved in establishing new methylation patterns during development and differentiation.
Abnormal DNA methylation patterns have been implicated in various diseases, including cancer, where global hypomethylation and promoter-specific hypermethylation can contribute to genomic instability, chromosomal aberrations, and silencing of tumor suppressor genes.
Methylation, in the context of genetics and epigenetics, refers to the addition of a methyl group (CH3) to a molecule, usually to the nitrogenous base of DNA or to the side chain of amino acids in proteins. In DNA methylation, this process typically occurs at the 5-carbon position of cytosine residues that precede guanine residues (CpG sites) and is catalyzed by enzymes called DNA methyltransferases (DNMTs).
DNA methylation plays a crucial role in regulating gene expression, genomic imprinting, X-chromosome inactivation, and suppression of repetitive elements. Hypermethylation or hypomethylation of specific genes can lead to altered gene expression patterns, which have been associated with various human diseases, including cancer.
In summary, methylation is a fundamental epigenetic modification that influences genomic stability, gene regulation, and cellular function by introducing methyl groups to DNA or proteins.
Ribonucleases (RNases) are a group of enzymes that catalyze the degradation of ribonucleic acid (RNA) molecules by hydrolyzing the phosphodiester bonds. These enzymes play crucial roles in various biological processes, such as RNA processing, turnover, and quality control. They can be classified into several types based on their specificities, mechanisms, and cellular localizations.
Some common classes of ribonucleases include:
1. Endoribonucleases: These enzymes cleave RNA internally, at specific sequences or structural motifs. Examples include RNase A, which targets single-stranded RNA; RNase III, which cuts double-stranded RNA at specific stem-loop structures; and RNase T1, which recognizes and cuts unpaired guanosine residues in RNA molecules.
2. Exoribonucleases: These enzymes remove nucleotides from the ends of RNA molecules. They can be further divided into 5'-3' exoribonucleases, which degrade RNA starting from the 5' end, and 3'-5' exoribonucleases, which start at the 3' end. Examples include Xrn1, a 5'-3' exoribonuclease involved in mRNA decay; and Dis3/RRP6, a 3'-5' exoribonuclease that participates in ribosomal RNA processing and degradation.
3. Specific ribonucleases: These enzymes target specific RNA molecules or regions with high precision. For example, RNase P is responsible for cleaving the 5' leader sequence of precursor tRNAs (pre-tRNAs) during their maturation; and RNase MRP is involved in the processing of ribosomal RNA and mitochondrial RNA molecules.
Dysregulation or mutations in ribonucleases have been implicated in various human diseases, such as neurological disorders, cancer, and viral infections. Therefore, understanding their functions and mechanisms is crucial for developing novel therapeutic strategies.
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.
Methyl Green is not typically considered a medical term, but it is a chemical compound that has been used in various medical and laboratory contexts. Here's the general definition:
Methyl Green is a basic dye, which is a type of organic compound with positively charged ions (cations). It is commonly used as a biological stain to selectively color certain structures in cells or tissues, such as nucleic acids (DNA and RNA), during microscopic examination.
In the medical field, Methyl Green has been used as a component of some topical ointments for treating superficial bacterial infections. However, its use is not widespread due to the availability of more effective antibiotics.
It's important to note that Methyl Green should not be confused with Methylene Blue, another basic dye that has broader medical applications, such as treating methemoglobinemia and used as a marker in some diagnostic tests.
Cytosine is one of the four nucleobases in the nucleic acid molecules DNA and RNA, along with adenine, guanine, and thymine (in DNA) or uracil (in RNA). The single-letter abbreviation for cytosine is "C."
Cytosine base pairs specifically with guanine through hydrogen bonding, forming a base pair. In DNA, the double helix consists of two complementary strands of nucleotides held together by these base pairs, such that the sequence of one strand determines the sequence of the other. This property is critical for DNA replication and transcription, processes that are essential for life.
Cytosine residues in DNA can undergo spontaneous deamination to form uracil, which can lead to mutations if not corrected by repair mechanisms. In RNA, cytosine can be methylated at the 5-carbon position to form 5-methylcytosine, a modification that plays a role in regulating gene expression and other cellular processes.
DNA restriction enzymes, also known as restriction endonucleases, are a type of enzyme that cut double-stranded DNA at specific recognition sites. These enzymes are produced by bacteria and archaea as a defense mechanism against foreign DNA, such as that found in bacteriophages (viruses that infect bacteria).
Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cleave the phosphodiester bonds between them. The recognition sites for these enzymes are usually palindromic, meaning that the sequence reads the same in both directions when facing the opposite strands of DNA.
Restriction enzymes are widely used in molecular biology research for various applications such as genetic engineering, genome mapping, and DNA fingerprinting. They allow scientists to cut DNA at specific sites, creating precise fragments that can be manipulated and analyzed. The use of restriction enzymes has been instrumental in the development of recombinant DNA technology and the Human Genome Project.
5-Methylcytosine (5mC) is a chemical modification of the nucleotide base cytosine in DNA, where a methyl group (-CH3) is added to the 5th carbon atom of the cytosine ring. This modification is catalyzed by DNA methyltransferase enzymes and plays an essential role in epigenetic regulation of gene expression, genomic imprinting, X-chromosome inactivation, and suppression of transposable elements in eukaryotic cells. Abnormal DNA methylation patterns have been associated with various diseases, including cancer.
Endodeoxyribonucleases are a type of enzyme that cleave, or cut, phosphodiester bonds within the backbone of DNA molecules. These enzymes are also known as restriction endonucleases or simply restriction enzymes. They are called "restriction" enzymes because they were first discovered in bacteria, where they function to protect the organism from foreign DNA by cleaving and destroying invading viral DNA.
Endodeoxyribonucleases recognize specific sequences of nucleotides within the DNA molecule, known as recognition sites or restriction sites, and cut the phosphodiester bonds at specific locations within these sites. The cuts made by endodeoxyribonucleases can be either "sticky" or "blunt," depending on whether the enzyme leaves single-stranded overhangs or creates blunt ends at the site of cleavage, respectively.
Endodeoxyribonucleases are widely used in molecular biology research for various applications, including DNA cloning, genome mapping, and genetic engineering. They allow researchers to cut DNA molecules at specific sites, creating defined fragments that can be manipulated and recombined in a variety of ways.
Haemophilus is a genus of Gram-negative, facultatively anaerobic bacteria that are commonly found as part of the normal microbiota of the human respiratory tract. However, some species can cause infections in humans, particularly in individuals with weakened immune systems or underlying medical conditions.
The most well-known species is Haemophilus influenzae, which was originally identified as a cause of influenza (hence the name), but it is now known that not all strains of H. influenzae cause this disease. In fact, the majority of H. influenzae infections are caused by strains that produce a polysaccharide capsule, which makes them more virulent and able to evade the host's immune system.
Haemophilus influenzae type b (Hib) was once a major cause of serious bacterial infections in children, including meningitis, pneumonia, and epiglottitis. However, since the introduction of vaccines against Hib in the 1980s, the incidence of these infections has decreased dramatically.
Other Haemophilus species that can cause human infections include Haemophilus parainfluenzae, Haemophilus ducreyi (which causes chancroid), and Haemophilus aphrophilus (which can cause endocarditis).
Deoxyribonucleases, Type II Site-Specific are a type of enzymes that cleave phosphodiester bonds in DNA molecules at specific recognition sites. They are called "site-specific" because they cut DNA at particular sequences, rather than at random or nonspecific locations. These enzymes belong to the class of endonucleases and play crucial roles in various biological processes such as DNA recombination, repair, and restriction.
Type II deoxyribonucleases are further classified into several subtypes based on their cofactor requirements, recognition site sequences, and cleavage patterns. The most well-known examples of Type II deoxyribonucleases are the restriction endonucleases, which recognize specific DNA motifs in double-stranded DNA and cleave them, generating sticky ends or blunt ends. These enzymes are widely used in molecular biology research for various applications such as genetic engineering, cloning, and genome analysis.
It is important to note that the term "Deoxyribonucleases, Type II Site-Specific" refers to a broad category of enzymes with similar properties and functions, rather than a specific enzyme or family of enzymes. Therefore, providing a concise medical definition for this term can be challenging, as it covers a wide range of enzymes with distinct characteristics and applications.
Phenolphthalein is not strictly a medical term, but it is a chemical compound that has been used in medical contexts. It's primarily known for its use as an acid-base indicator in chemistry and medical laboratory tests. Here's the general definition:
Phenolphthalein is a crystalline compound, commonly available as a colorless powder or clear liquid. It is used as a pH indicator, turning pink to purple in basic solutions (pH above 8.2) and colorless in acidic solutions (pH below 8.2). This property makes it useful in various applications, such as titrations and monitoring the pH of chemical reactions or solutions.
In a medical context, phenolphthalein has historically been used as an active ingredient in certain over-the-counter laxatives. However, due to concerns about potential carcinogenicity and other side effects, its use in pharmaceuticals has been largely discontinued or restricted in many countries, including the United States.
Exonucleases are a type of enzyme that cleaves nucleotides from the ends of a DNA or RNA molecule. They differ from endonucleases, which cut internal bonds within the nucleic acid chain. Exonucleases can be further classified based on whether they remove nucleotides from the 5' or 3' end of the molecule.
5' exonucleases remove nucleotides from the 5' end of the molecule, starting at the terminal phosphate group and working their way towards the interior of the molecule. This process releases nucleotide monophosphates (NMPs) as products.
3' exonucleases, on the other hand, remove nucleotides from the 3' end of the molecule, starting at the terminal hydroxyl group and working their way towards the interior of the molecule. This process releases nucleoside diphosphates (NDPs) as products.
Exonucleases play important roles in various biological processes, including DNA replication, repair, and degradation, as well as RNA processing and turnover. They are also used in molecular biology research for a variety of applications, such as DNA sequencing, cloning, and genome engineering.
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.
Endonucleases are enzymes that cleave, or cut, phosphodiester bonds within a polynucleotide chain, specifically within the same molecule of DNA or RNA. They can be found in all living organisms and play crucial roles in various biological processes, such as DNA replication, repair, and recombination.
Endonucleases can recognize specific nucleotide sequences (sequence-specific endonucleases) or have no sequence preference (non-specific endonucleases). Some endonucleases generate sticky ends, overhangs of single-stranded DNA after cleavage, while others produce blunt ends without any overhang.
These enzymes are widely used in molecular biology techniques, such as restriction digestion, cloning, and genome editing (e.g., CRISPR-Cas9 system). Restriction endonucleases recognize specific DNA sequences called restriction sites and cleave the phosphodiester bonds at or near these sites, generating defined fragment sizes that can be separated by agarose gel electrophoresis. This property is essential for various applications in genetic engineering and biotechnology.
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.
I'm sorry for any confusion, but "Celosia" is not a medical term. It is actually the name of a genus of flowering plants, also known as cockscomb or woolflower, which are often grown as ornamental plants due to their vibrant and unique flowers. If you have any medical terms or concepts that you would like me to define or explain, I'd be happy to help!
Expectorants are a type of medication that help to thin and loosen mucus in the airways, making it easier to cough up and clear the airways. They work by increasing the production of fluid in the respiratory tract, which helps to moisten and soften thick or sticky mucus. This makes it easier for the cilia (tiny hair-like structures that line the airways) to move the mucus out of the lungs and into the throat, where it can be swallowed or spit out.
Expectorants are often used to treat respiratory conditions such as bronchitis, pneumonia, and chronic obstructive pulmonary disease (COPD), which can cause excessive mucus production and difficulty breathing. Some common expectorants include guaifenesin, iodinated glycerol, and potassium iodide.
It is important to follow the dosage instructions carefully when taking expectorants, as taking too much can lead to side effects such as nausea, vomiting, and diarrhea. It is also important to drink plenty of fluids while taking expectorants, as this can help to thin the mucus and make it easier to cough up.
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.
Viral DNA refers to the genetic material present in viruses that consist of DNA as their core component. Deoxyribonucleic acid (DNA) is one of the two types of nucleic acids that are responsible for storing and transmitting genetic information in living organisms. Viruses are infectious agents much smaller than bacteria that can only replicate inside the cells of other organisms, called hosts.
Viral DNA can be double-stranded (dsDNA) or single-stranded (ssDNA), depending on the type of virus. Double-stranded DNA viruses have a genome made up of two complementary strands of DNA, while single-stranded DNA viruses contain only one strand of DNA.
Examples of dsDNA viruses include Adenoviruses, Herpesviruses, and Poxviruses, while ssDNA viruses include Parvoviruses and Circoviruses. Viral DNA plays a crucial role in the replication cycle of the virus, encoding for various proteins necessary for its multiplication and survival within the host cell.
List of MeSH codes (D08)
High-resolution genome-wide cytosine methylation profiling with simultaneous copy number analysis and optimization for limited...
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A quantitative HpaII-PCR assay to measure methylation of DNA from a small number of cells. | College of Agricultural Sciences
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Ann. Rev. Genet. 1981, 15:265-94
MspI1
- By expanding the representation to smaller fragments using HpaII or MspI, we increase the representation by these isoschizomers to more than 1.32 million loci in the human genome, representing 98.5% of CpG islands and 91.1% of refSeq promoters. (nih.gov)
Type II Site-Specific1
- One of the Type II site-specific deoxyribonucleases (EC 3.1.21.4). (umassmed.edu)
TYPE II SITE-SPECIFIC1
- One of the Type II site-specific deoxyribonucleases (EC 3.1.21.4). (nih.gov)