Studies on the molecular basis of Gc polymorphism.
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Animals↗
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Results for “Molecular polymorphism”
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Molecular diversity of Renibacterium salmoninarum isolates determined by randomly amplified polymorphic DNA analysis.
The molecular diversity among 60 isolates of Renibacterium salmoninarum which differ in place and date of isolation was investigated by using randomly amplified polymorphic DNA (RAPD) analysis. Isolates were grouped into 21 banding patterns which did not reflect the biological source. Four 16S-23S rRNA intergenic spacer (ITS1) sequence variations and two alleles of an exact tandem repeat locus, ETR-A, were the bases for formation of distinct groups within the RAPD clusters. This study provides evidence that the most common ITS1 sequence variant, SV1, possesses two copies of a 51-bp repeat unit at ETR-A and has been widely dispersed among countries which are associated with mainstream intensive salmonid culture.
Animals↗
The polymorphism of acetylcholinesterase: post-translational processing, quaternary associations and localization.
The molecular forms of acetylcholinesterase (AChE) correspond to various quaternary structures and modes of anchoring of the enzyme. In vertebrates, these molecules are generated from a single gene: the catalytic domain may be associated with several types of C-terminal peptides, that define distinct types of catalytic subunits (AChE(S), AChE(H), AChE(T)) and determine their post-translational maturation. AChE(S) generates soluble monomers, in the venom of Elapid snakes. AChE(H) generates GPI-anchored dimers, in Torpedo muscles and on mammalian blood cells. AChE(T) is the only type of catalytic subunit that exists in all vertebrate cholinesterases; it produces the major forms in adult brain and muscle. AChE(T) generates multiple structures, ranging from monomers and dimers to collagen-tailed and hydrophobic-tailed forms, in which catalytic tetramers are associated with anchoring proteins that attach them to the basal lamina or to cell membranes. In the collagen-tailed forms, AChE(T) subunits are associated with a specific collagen, ColQ, which is encoded by a single gene in mammals. ColQ contains a short peptidic motif, the proline-rich attachment domain (PRAD), that triggers the formation of AChE(T) tetramers, from monomers and dimers. The critical feature of this motif is the presence of a string of prolines, and in fact synthetic polyproline shows a similar capacity to organize AChE(T) tetramers. Although the COLQ gene produces multiple transcripts, it does not generate the hydrophobic tail. P, which anchors AChE in mammalian brain membranes. The coordinated expression of AChE(T) subunits and anchoring proteins determines the pattern of molecular forms and therefore the localization and functionality of the enzyme.
Acetylcholinesterase↗
[IS6110-restriction fragment length polymorphism based DNA fingerprinting in molecular epidemiology of tuberculosis].
OBJECTIVE: To identify the IS6110-restriction fragment length polymorphism (RFLP) DNA fingerprinting patterns of some clinical isolates of Mycobacterium tuberculosis (MTB) isolated from Ningxia, Beijing and Shanghai in recent years, and to observe their epidemiological characteristics. METHODS: Chromosomal DNA of MTB was digested with endonuclease PvuII, then electrophoresed on agarose gel plate and transferred capillarilly to a nylon filter and hybridized with 245 bp fragment of IS6110 which labeled using random primer fluorescein labeling kit. The RFLP patterns of Southern hybridization were inspected autofluorographically and the chromosomal DNAs of MTB were thereby typed. RESULTS: Most of 103 isolates of MTB shared 8 approximately 21 copies. Some of them were clustered. Strains isolated from Ningxia and Beijing had similar DNA fingerprinting patterns. One zero copy strain and one single copy strain were found among isolates from Shanghai. CONCLUSIONS: IS6110-RFLP based typing is feasible for MTB molecular epidemiological study in China. Most of isolates of MTB show analyzable patterns. Isolates of MTB from Ningxia and Beijing have close genomic relation.
China↗
Size polymorphisms due to changes in the number of O-glycosylated tandem repeats in the Dictyostelium discoideum glycoprotein PsA.
The molecular weight polymorphism in the Dictyostelium discoideum cell surface glycoprotein PsA is due to incremental copies of an O-glycosylated tandem tetrapeptide repeat. Allelic variation at the pspA locus results in a PsA glycoprotein with three, four or five tandem copies of Pro-Thr-Val-Thr. The simplest explanation for the origin of this polymorphism is an unequal crossing over event in the ancestral gene containing four copies. Each Thr in the tandem repeat is substituted with carbohydrate, which is completely absent from PsA in strains carrying a glycosylation defective modB mutation. Glycosylated tandem repeats appear to be a common feature of cell surface glycoproteins which are characterized by short domains rich in Pro and Thr or Ser. It is probable that the glycosylated repeat domain acts as a "spacer" peptide that projects the globular domain above the glycocalyx.
Amino Acid Sequence↗
Preferential enrichment: significant influence of minor molecular modification on the mode of polymorphic transition during crystallization.
The relationship between the molecular structure and the occurrence of Preferential Enrichment, an unusually symmetry-breaking enantiomeric resolution phenomenon observed upon simple recrystallization of a certain kind of racemic crystals from organic solvents, has been investigated with respect to a new series of racemic ammonium sulfonate compounds. Racemic [2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]ethyl]trimethylammonium p-iodobenzenesulfonate [(+/-)-1a] can show preferential enrichment by simple recrystallization from EtOH, whereas its terminal methoxy and propoxy derivatives [(+/-)-1b and (+/-)-1c] are unable to do so. The influence of such a minor molecular modification on Preferential Enrichment has been rationalized in terms of the change of the mode of polymorphic transition during crystallization, which has been confirmed by in situ ATR-FTIR (ReactIR) spectroscopy in solution and in the solid state and by X-ray crystallographic analysis of their single crystals.
Journal Article↗
Presence and genetic polymorphism of an epithelial mucin in milk of the goat (Capra hircus).
1. Analysis of individual samples of goat's milk by SDS-PAGE confirmed that they contain a polymorphic, high molecular weight (M(r) greater than 205 kDa) glycoprotein. 2. On SDS-gels, the polymorphism takes the form of two bands of variable mobility which usually stain with equal intensity. This polymorphism resembles that detected in milk mucins of other species and is best explained by an expression of codominant genes containing variable numbers of a tandemly repeated 60-base segment. 3. Analysis of milk fractions provided evidence that the goat mucin is exclusively a membrane protein, and that it can be purified from other fat globule proteins by gel filtration and peanut lectin affinity chromatography. 4. Among proteins in the goat milk fat globule, the mucin appears to be a strong immunogen but the resulting antibodies applied to Western blots only stained the cow's milk mucin mildly and the guinea pig and human milk mucins not at all.
Animals↗
Molecular and serological analysis of polymorphisms in the murine major histocompatibility complex-encoded proteasome subunits, LMP-2 and LMP-7.
LMP-2 and LMP-7, gamma-interferon-inducible subunits of the 20S proteasome, play an important role in antigen processing. To define the molecular basis of their polymorphism, we sequenced Lmp-2 and Lmp-7 cDNA from nine different strains of mice. Three allelic variants of both LMP-2 and LMP-7 were found, but all of the polymorphism in LMP-7 is clustered near the carboxyl terminus of the molecule. We confirmed the nucleotide sequence changes at the protein level in both the unprocessed and processed forms of the molecules by analysis of specific anti-LMP-2, anti-LMP-7 and anti-proteasome immunoprecipitates on two-dimensional PAGE gels. Interestingly, a single amino acid change at position 272 between LMP-7b,d,q and LMP-7k,s,f,x,g7, cas4 from glycine to arginine dramatically affects its migration on SDS-PAGE gels, suggesting the possibility of allele-specific posttranslational modification.
Amino Acid Sequence↗
[Molecular typing by amplified fragment length polymorphism and PCR-restriction fragment length polymorphism , biotyping and antimicrobial susceptibility of Campylobacter jejuni].
Molecular typing systems have provided invaluable information for tracking infectious agents through the food chain. These tools have been essential for understanding the epidemiology of gastrointestinal infectious diseases, therefore providing essential and evidence-based information for appropriate interventions and preventative measures. Two such molecular typing techniques based on the polymerase chain reaction (PCR) that have been applied to the epidemiology of foodborne pathogens are, amplified fragment length polymorphism (AFLP) and restriction fragment length polymorphism (RFLP) analysis. Campylobacter is responsible for one of the most common bacteria foodborne gastrointestinal infections affecting humans, especially in developed countries. The object of this paper is to apply AFLP and RFLP analysis of the flagellin (flaA) gene to 18 isolates of Campylobacter jejuni from human sporadic cases in Italy. Results of these analyses were compared to the phenotypes of these isolates based on biotyping and antimicrobial resistance determinations. All isolates were typable by the four methods. The RFLP procedure was performed with DdeI and HinfI enzymes, and 12 and 8 distinct profiles respectively were recognised. AFLP analysis was more discriminatory, and recognised 16 different profiles. Results from AFLP were reproducible and applicable for definitive characterisation of C. jejuni isolated from different outbreaks. PCR-RFLP of the flaA gene represents a useful tool only to compare isolates within a single outbreak.
Anti-Bacterial Agents↗
A note on the hypothesis: protein polymorphism as a phase of molecular evolution.
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Biological Evolution↗
Transmission of tuberculosis in Havana, Cuba: a molecular epidemiological study by IS6110 restriction fragment length polymorphism typing.
The combination of molecular and conventional epidemiological methods has improved the knowledge about the transmission of tuberculosis in urban populations. To examine transmission of tuberculosis in Havana, Cuba, with DNA fingerprinting, we studied 51 out of 92 Mycobacterium tuberculosis strains isolated from tuberculosis patients who resided in Havana and whose infection was culture-confirmed in the period from September 1997 to March 1998. Isolates from 28 patients (55%) had unique IS6110 restriction fragment length polymorphism (RFLP) patterns, while isolates from 23 others (45%) had identical patterns and belonged to 7 clusters. Three clusters consisting of six, five and two cases were each related to small outbreaks that occurred in a closed setting. Three other clustered cases were linked to a large outbreak that occurred in another institution. Younger patients were more correlated to clustering than older ones. The finding that 45% of the isolates had clustered RFLP patterns suggests that recent transmission is a key factor in the tuberculosis cases in Havana. The IS6110 RFLP typing made it possible to define the occurrence of outbreaks in two closed institutions.
Adult↗
Conformational polymorphism VI: the crystal and molecular structures of form II, form III, and form V of 4-amino-N-2-pyridinylbenzenesulfonamide (sulfapyridine).
The crystal structures of three crystalline forms of 4-amino-N-pyridinylbenzenesulfonamide (sulfapyridine) have been determined by X-ray single crystal structure analysis. Form II crystallizes in space group P2(1)/c with four molecules in the unit cell: a = 0.6722(1) nm, b = 2.0593(5) nm, c = 0.8505(1) nm, beta = 101.14(1) degrees; Form III crystallizes in space group C2/c with eight molecules in the unit cell: a = 1.2830(2) nm, b = 1.1714(3) nm, c = 1.5400(3) nm, beta = 94.12(1) degrees; Form V crystallizes in the orthorhombic space group Pbca with 16 molecules in the unit cell: a = 2.4722(10) nm, b = 1.5710(15) nm, c = 1.2147(7) nm. The three structures were solved by direct methods and refined anisotropically to R factors of 0.045, 0.052, and 0.063, respectively. Bond lengths and bond angles agree well among the molecules in these structures; however, the system exhibits conformational polymorphism since the molecular conformation, as measured by torsion angles, differs significantly among the three forms. Sulfapyridine exhibits the imide configuration in all three structures rather than the amide form present in other sulfonamide compounds. Using the structural data, the powder patterns of the three forms have been computer generated to provide standard diffraction patterns for comparison with the variety of polymorphic forms reported in the literature.
Chemical Phenomena↗
Detection and investigation of Campylobacter jejuni by polymerase chain reaction-restriction fragment length polymorphism analysis.
A molecular typing approach for Campylobacter jejuni with restriction fragment length polymorphism (RFLP) analysis of the flagellin gene flaA in C. jejuni, was generated and studied. Using polymerase chain reaction (PCR)-RFLP with the restriction endonuclease Mbo I, it was demonstrated that C. jejuni could be divided into four types. Genotypic analysis of C. jejuni by PCR-RFLP is a valuable technique for epidemiological typing.
Animals↗
[Analysis of HLA-DQWa antigen ethnic polymorphism among a Japanese and Caucasian population and an association with Harada's disease].
A novel HLA-DQ antigen, DQWa was analysed with its serological, immunochemical, and molecular biological polymorphism. Furthermore, A disease association with DQWa was analysed by investigating HLA antigen frequencies of 24 patients with Harada's disease. DQWa was in linkage disequilibrium mainly with DR4-Dw15 in Japanese, and with DRw8 -Dw8 in Caucasians. The former haplotype was observed only in Japanese. A significant increase of DQWa was observed in the patients with Harada's disease (73.9% compared with 35.9% of the control, chi 2 = 9.77, P less than 0.005, Pc less than 0.05, Relative risk = 5.17). DQWa antigen molecules were different from each other between Japanese and in Caucasians, when they were analysed immunochemically by two dimensional electrophoresis, or molecular biologically by restriction fragment length polymorphism analysis. These results suggest that HLA-DQWa antigen may play a role in the pathogenesis of Harada's disease, which is seen only in Japanese.
Asian People↗
Identification by random amplification of polymorphic DNA of a common molecular type of Cryptococcus neoformans var. neoformans in patients with AIDS or other immunosuppressive conditions.
Sixty clinical isolates of Cryptococcus neoformans var. neoformans were analyzed by random amplification of polymorphic DNA (RAPD) using 12- to 22-mer primers in pairs. Five major profiles, which clearly distinguished between serotypes A (profiles I-III), AD (profile IV), and D (profile V), were identified. Forty-two of 58 serotype A isolates were assigned to profile I, 13 to profile II, and 3 to profile III. Profile I compromised 5 subtypes (profiles Ia-Ie), with 37 to 42 isolates in profile Ia. Twenty-seven of 28 isolates from patients with AIDS belonged to profile Ia (P<.001), as did 7 of 10 isolates from otherwise immunocompromised patients. Isolates from immunocompetent hosts were broadly distributed (profile I, 8 isolates; profile II, 10 isolates; profile III, 2 isolates). RAPD profiles were independent of body site and geographic origin of isolates. Isolates pairs from 3 patients produced identical profiles. A predominant genetic profile among serotype A strains from AIDS patients has not been reported previously.
AIDS-Related Opportunistic Infections↗
[Molecular-genetic analysis of VNTR polymorphism in alleles of the phenylalanine hydroxylase gene in inhabitants of the Volga-Urals region].
Molecular genetic analysis of the VNTR alleles at the phenylalanine hydroxylase (PAH) gene was carried out in seven Volga-Ural ethnic groups (Bashkirs, Tatars, Chuvashes, Maris, Mordovians, Udmurts, and Komis). The PCR fragments revealed included alleles of 380, 440, 470, 500, 530, 560, and 650 bp, containing 3, 5, 6, 7, 8, 9, and 12 repeat copies, respectively. Substantial heterogeneity of the populations in respect to the distribution and frequency of the VNTR alleles and genotypes was demonstrated. The indices of observed and theoretical heterozygosity of the PAH VNTR alleles were calculated. The mean heterozygosity index was 70.02%. This high index value along with the established differentiation of the populations in respect to the frequency distribution of the VNTR alleles and PAH genotypes permitted the conclusion that the given polymorphic locus can serve as a highly informative marker for examination of the genetic structure of the Volga-Ural populations.
Alleles↗
Molecular basis of galactosemia: mutations and polymorphisms in the gene encoding human galactose-1-phosphate uridylyltransferase.
We describe the molecular characterization of two mutations responsible for galactosemia, an inherited disorder of galatose metabolism that causes jaundice, cataracts, and mental retardation in humans. The coding region of galactose-1-phosphate uridylyltransferase (GALT; UDPglucose:alpha-D-galactose-1-phosphate uridylyltransferase, EC 2.7.7.12) was amplified by the polymerase chain reaction from total cDNA of a classic galactosemic individual and was characterized by direct sequencing of the products. Two missense mutations were identified: (i) replacement of valine-44 by methionine and (ii) replacement of methionine-142 by lysine. These mutations led to a drastic reduction in GALT activity when individual mutant cDNAs were overexpressed in a mammalian cell system, although full-length protein is synthesized in this assay. The two galactosemia mutations account for 3 of the 15 galactosemia alleles analyzed. These results suggest that galactosemia is caused by a variety of mutations, which might be responsible for the observed clinical heterogeneity of this disorder. We also present the molecular characterization of two GALT polymorphisms: (i) replacement of leucine-62 by methionine and (ii) replacement of asparagine-314 by aspartate. It appears that galactosemia mutations tend to occur in regions that are highly conserved throughout evolution while the polymorphisms change variable residues.
Amino Acid Sequence↗
Molecular genetic analysis of the polymorphic apolipoprotein E in modern and ancient human DNA samples.
In this report, methodical bases for the molecular genetic analysis of the three common apolipoprotein E alleles APOE*2, APOE*3 and APOE*4 in DNA isolated from ancient human skeletal remains are described. Considering that ancient DNA target regions for amplification are generally quite small, the detection method is based on short amplification products in the range from 71 bp to 75 bp. The applicability of the modified method for APOE genotyping was examined in modern human DNA samples.
Apolipoproteins E↗