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At least 19 recordsLinked to original sources
PubMed2025

Maternal-Foetal HLA-DQB1 Incompatibility Is Associated With Pregnancy-Induced Hypertensive Disorders in a Genetically Isolated Population.

In pregnancy, semi-allogenic foetal trophoblasts express a specific HLA profile mediating maternal leukocyte contact, crucial for placentation. Paradoxically, maternal immunomodulation requires foetal antigen recognition, especially involving certain HLA molecules. Pre-eclampsia, a severe hypertensive complication, has been linked to antigenic similarity. Previously, we showed no selection for HLA (in)compatibility in uncomplicated naturally conceived pregnancies. However, pre-eclamptic pregnancies were associated with increased total maternal-foetal HLA and HLA-C matching. These associations suggest a role for HLA mismatches in immune regulation leading to an uncomplicated pregnancy. To better understand HLA homozygosity in human reproduction, we aimed to determine if there is a preferential selection for HLA compatibility in a genetically isolated population, and its relation to hypertensive complications. A nested case-control study, comprising 125 uncomplicated pregnancies and 50 with hypertensive complications (29 with pregnancy-induced hypertension, 21 with pre-eclampsia) was conducted in a genetically isolated Dutch population (FROH 1.3-3.1). Maternal and foetal HLA-A, -B, -C, -DRB1, -DQA1, -DQB1 and maternal killer-cell immunoglobulin-like receptor (KIR) genotyping were performed. Maternal-foetal HLA (mis)match counts were compared to expected values from randomisation of paternal HLA haplotypes over maternal haplotypes of the foetuses. Mismatched CD4+ T cell epitopes presented by maternal HLA class II were predicted using the PIRCHE-II algorithm. In uncomplicated pregnancies, no difference was found between observed and expected maternal-foetal HLA (mis)matches. However, pregnancies with hypertensive complications showed significantly higher observed HLA-DQB1 mismatches, reflected in PIRCHE-II scores. No significant differences were found in KIR/HLA-C frequencies. Interpretation is limited by the small sample size and the grouping of distinct hypertensive disorders. Nonetheless, maternal-foetal HLA-DQB1 mismatch seems to play a role in the aetiology of hypertensive complications during pregnancy in this population.

Humans↗
PubMed2025

A Complete Picture of the CYP2D6 Heterogeneity in Northeastern Italian Genetic Isolates.

The CYP2D6 gene is a highly polymorphic pharmacogene involved in the metabolism of 25% of commonly used drugs. We aim to assess the feasibility of extracting relevant pharmacogenomic information from Whole Genome Sequencing (WGS) data and to highlight any difference in CYP2D6 allele frequencies between the northeastern Italian and European populations. To achieve this aim, WGS was performed on two cohorts: 664 individuals from six different isolated communities (FIC) and 123 outbred Italian individuals (FOP). In silico CYP2D6 genotyping was performed and allele frequencies from the FIC cohort were compared to those of FOP and European individuals from 1000 Genomes. Interestingly, 18 alleles identified in FIC were absent in the control cohorts. In particular, 13 individuals carried the extremely rare CYP2D6*28x2 allele, whose activity is unknown. Moreover, we identified a carrier of the CYP2D6*34x2 allele, which has never been described before. The population structure and genetic differentiation of the cohorts were investigated, revealing that the genetic isolates differ only slightly from the outbred and the European populations, but still offer new insight into CYP2D6 heterogeneity. The findings described here will be relevant to tailoring the treatments in the northeastern Italian population.

Cytochrome P-450 CYP2D6↗
PubMed1978

Isolation, genetic mapping and some characterization of a mutation in Escherichia coli that affects the processing of ribonuleic acid.

Temperature-sensitive mutants were isolated from an rnc (RNase III-) strain of Escherichia coli, and their rRNA metabolism was analyzed on 3% polyacrylamide gels. One of these mutants was unable to produce 23S and 5S rRNAs at the nonpermissive temperature. When an rnc+ allele was introduced to this strain, it remained temperature sensitive. At the nonpermissive temperature, this strain could then produce 23S rRNA but was unable to make normal levels of 5S rRNA. In matings and transduction experiments, the defect in rRNA metabolism and temperature sensitivity behaved as a syndrome caused by a single point mutation, which was mapped at min 23.5 on the E. coli chromosome. This mutation probably affects an enzyme, ribonuclease E (RNase E), which introduces a cut in the nascent rRNA transcript between the 23S and the 5S rRNA cistrons. The mutation rne is recessive with respect to temperature sensitivity and the pattern of rRNA. Revertants able to grow at 43 degrees and with normal metabolism of rRNA were isolated; genetic analysis showed that they do not contain the original rne mutation, suggesting that they were true revertants. By combining the rne mutation with an rnc mutation, double rnc rne strains were synthesized, which behaved very similarly to the original rnc strain from which the rne mutation was isolated. Such strains have RNA metabolism that is similar to that of rnc strains at permissive temperatures, but at the nonpermissive temperature they fail to synthesize p23, m23, and 5S rRNAs. Thus, the experiments reported here, together with previous studies, suggest the existence of a new processing ribonuclease activity in Escherichia coli, which is called ribonuclease E.

Electrophoresis, Polyacrylamide Gel↗
PubMed1977

Isolation, genetic analysis, and characterization of Escherichia coli mutants with defects in the lacY gene.

Five hundred thirty-five lacY mutants were isolated from an Escherichia coli strain carrying the lactose operon on an F' factor, either without mutagenesis or after mutagenesis with 2-aminopurine or N-methyl-N'-nitro-N-nitrosoguanidine. Crosses against 48 independently isolated deletions ending in the lacY gene divided the gene into 36 deletion groups. Suppressibility studies with 7 nonsense suppressor strains classified 276 mutants as nonsense mutants and 78 as missense (or nonsuppressible) mutants. One hundred seventy-nine mutants were "leaky" and could not be so allocated, and two were found to have small internal deletions. Nonsense mutants could in many cases be subdivided even within deletion groups on the basis of their suppressibility pattern, giving a total of 70 groups of nonsense mutants. Studies of these mutants allow the following conclusions: lactose and melibiose most probably do not have separate binding sites on the permease; the lacY region most likely consists of one cistron, and so both active transport and facilitated diffusion are functions of one protein; and finally, there is probably no small defined region of the permease responsible for energy coupling of transport. Furthermore, the strains and the analysis form the basis for a future functional study of the permease by biochemical techniques.

2-Aminopurine↗
PubMed1979

[New transducing phage with RNA polymerase beta- and beta'-subunit genes derived from a hybrid phage lambda att80: isolation, genetic analysis and physical mapping].

A hybrid lambda att 80 phage with the genetic structure lambda (A-J) phi 80 (att-int-xis) imm lambda..cI857s7 is shown to be a convenient vector for creating transducing phages. On the one hand, the restriction analysis indicates that it has 3 restriction sites for EcoRI in comparison with 5 and 9 sites for parental phages lambda and phi 80 respectively. On the other hand, its buoyant density is less than that of phage lambda and under centrifugation it is easier separated from the phage transducing particles. When lambda att 80 prophage was excluded from the bfe locus of Escherichia coli, transducing phages with genes of two RNA polymerase beta-subunits (rpoB and rpoC) were isolated. To identify the latter, a convenient genetic test was worked out. A physical map of lambda att 80 drifd 35 transducing phage, carrying rpoB and rpoC genes has been constructed using endonucleases EcoRI and HindIII. A comparison of this map and the corresponding maps of transducing phages lambda drifd 18 and lambda drifd 47, studied earlier, led to the discovery of two integration sites of phage lambda within the locus bfe spaced apart by about 1800 nucleotide pairs. At all the sites both phages (lambda and lambda att 80) have integrated in the locus bfe in the counter clockwise order.

Bacteriophage lambda↗
PubMed1979

A search for association between IgD concentrations and immunoglobulin allotypes in 936 sera from a genetic isolate in Newfoundland.

Immunoglobulin allotype (Gm) data has been analysed agaonst immunoglobulin D (IgD) concentrations in a population study in Newfoundland. There was no significant difference between the distribution of IgD concentrations in people homozygous for the alleles G1m(f) and G3m(b) when compared with people homozygous for the alleles G1m(a) and G3m(g). These findings, involving 573 homozygous individuals as opposed to ninety-eight in an earlier study on a New York population, do not confirm the earlier findings. Thus a genetic influence on IgD concentration by Gm genes or genes closely linked to them is not universally demonstrable by typing for these four markers and by using the Mancini technique for mearusing IgD concentration.

Gene Frequency↗
PubMed1979

High prevalence of diabetes in young Pima Indians: evidence of phenotypic variation in a genetically isolated population.

Medical records of the Pima Indian population aged 0--24 yr were reviewed for a diagnosis of diabetes before initiation of glucose tolerance testing. None of 1556 subjects below age 15, but 6 of 657 aged 15--24, had a previous diagnosis. Of the six known diabetics, five had been treated with insulin and four had had ketoacidosis. Subsequently, plasma glucose levels were determined after a 75-g oral carbohydrate load in 1712 subjects aged 5--24 yr, which is about 78% of the eligible population. Previously diagnosed diabetes and asymptomatic hyperglycemia were more frequent in subjects 15--24 yr old than were reported in other populations. Glucose intolerance in young Pimas was associated with obesity. In Pima offspring, the presence of diabetes in both parents was related to glucose tolerance in those above but not below the age of 15 yr. Both asymptomatic hyperglycemia and insulin-requiring diabetes occurred frequently in young Pimas, suggesting that these syndromes represent the clinical spectrum of a single disease in the Pima Indian.

Adolescent↗
PubMed1978

Adenosine kinase as a new selective marker in somatic cell genetics: isolation of adenosine kinase--deficient mouse cell lines and human--mouse hybrid cell lines containing adenosine kinase.

A new selective system for isolating somatic cell hybrids, using adenosine kinase as the selective marker, has been developed. The selective medium for forward selection (to select for cells containing adenosine kinase) contains alanosine, adenosine and uridine. To survive in the presence of alanosine, cells must have adenosine kinase in order to utilize exogenous adenosine as the sole source of AMP. Uridine is added to the selective medium to prevent the toxic effects of adenosine on cultured mammalian cells. The selective medium for reverse selection (to select for cells lacking adenosine kinase) contains 2-fluoroadenosine, an analogue of adenosine, which is converted to a toxic nucleotide by the action of adenosine kinase. Mouse mutant cell lines deficient in adenosine kinase have been derived. Human--mouse hybrid cells containing the kinase have been prepared from one of these mutant lines. Karyotype data of these hygrid lines and their adenosine kinase-minus sublines are consistent with assignment by others of the human gene for adenosine kinase on chromosome 10.

Adenosine↗
PubMed1979

["Teratologic series" and their genetics].

Isolated cyclopia is one of the members of the prosencephalic teratologic series. In some families with cyclopian monster other types of prosencephalic malformations are found in sibs or more distant relatives. All these malformations occur more frequently in females. Different forms of prosencephalies are observed in the same type of chromosome disbalance. These data suggest that morphogenesis and etiology of the prosencephalic malformations are common. Therefore a whole teratologic series but not a single member-malformation must be an object of genetic analysis. The same data are found for another teratologic series: bilateral renal agenesis--unilateral one--aplastic variant of the cystic dysplasia of kidneys. Polygenic inheritance with the threshold phenomenon is the most probable type of genetic determination of such malformations. The more frequent occurrence of polygenic malformations in families with the studied malformation whose inheritance is not yet established may be an indirect indication for the polygenic determination of the latter.

Abnormalities, Severe Teratoid↗
PubMed1978

[Isolation and genetic study of Aspergillus nidulans mutants defective in pyrimidine biosynthesis].

8 uridine-requiring pyr mutants were isolated from Aspergillus nidulans under nitrosoguanidine treatment. All the mutants are capable to grow on the medium containing 20 mkg/ml of uridine or cytidine, or 100 mkg/ml of uracil, and they do not utilize thymidine, thymine, cytosine and deoxyuridine. Their ability to grow in the presence of orotic acid demonstrates that the pyrimidine synthesis in all the mutants is blocked at stages preceding the conversion of orotic acid into orotidine monophosphate. All the pyr mutants are of nuclear nature, they are recessive and represent three complementation groups located in the VIII chromosome. Unlike U. maydis mutant, the requirement in pyrimidines does not increase the sensitivity of A. nidulans pyr mutants to UV-irradiation.

Aspergillus nidulans↗
PubMed1979

Isolation and genetic analysis of nuclease halo (nuh) mutants of Neurospora crassa.

Nuclease halo (nuh) mutants of the ascomycete Neurospora crassa have been isolated which are characterized reduced release of deoxyribonuclease (DNase) activities from colonies grown on sorbose-containing agar media. To identify nuh mutants, mutagenized isolates were transferred to commercial DNase test agar, or grown on minimal medium and then overlayed with agar that contained heat-denatured DNA. DNase activity was visualized by acid precipitation which produced clear rings of digestion (haloes) around the colonies. To identify the number of genes in which mutations lead to reduced release of nuclease activity, eleven nuh mutants were checked for close linkage and linked pairs were tested for complementation. These mutants were assigned to eight genes, and all except one were mapped in six small regions of the Neurospora linkage maps. In addition, among a large number of existing mutants which were tested for nuclease haloes, two mutants were found that showed the Nuh phenotype, namely uvs-3 and uvs-6. One of the isolated nuh mutants was also found to be sensitive to UV and was mapped close to uvs-3; it may represent a new allele of this gene. As a first step towards identification of genuine nuclease mutants, extensively backcrossed strains of mutants from different genes have been assayed for nuclease activity with denatured DNA in extracts. A pronounced reduction, compared to wild type at the same stage of growth, was found in uvs-3 and also in nuh-3, a mutant that is not UV-sensitive.

Chromosome Mapping↗
PubMed1977

Isolation and genetic analysis of deletion mutants of colicin E1 plasmids carrying a TnA insertion.

Deletions of colicin E1 (colE1) plasmid deoxyribonucleic acid (DNA) carrying the TnA transposon have been isolated. All except two were generated by nuclease digestion of plasmid DNA from its EcoRI-sensitive site. A plasmid containing about 16% of the ColE1 DNA (6.5 X 10(5) daltons) was generated that also contained the part of the TnA transposon conferring ampicillin resistance. The extents of different deletions were determined by analysis of restriction endonuclease fragments generated by the restriction endonucleases HaeII, BamHI, and HincII.

Ampicillin↗
PubMed1977

Temperature-sensitive respiratory-deficient mitochondrial mutations: isolation and genetic mapping.

In order to find new genetic loci and functions on the yeast mitochondrial DNA, especially mutations affecting the mitochondrial protein synthesis apparatus, temperature sensitive mutants have been isolated after MnCl2 mutagenesis and mitochondrial and nuclear mutants classified according to their pattern of recombination with three rho- tester strains. Eighteen cold- and heat-sensitive respiratory deficient mitochondrial mutants have been isolated and localized on the mitochondrial genome by deletion mapping using 113 rho- strains. Eight of them appear to represent new loci, among which some are probably mutations of the tRNA and rRNA genes.

Cold Temperature↗
PubMed1979

The isolation and genetic characteristics of lambda transducing phages of the uvrA+ and uvrC+ genes of E. coli K12.

Lambda transducing phages carrying the excision repair genes uvrA+ and uvrC+ were selected from a pool of lambda phages carrying EcoR1 fragments of E. coli DNA. These phages and also lambdauvrB+ (obtained from Gottesman) were used to make lysogens of excision-defective strains carrying uvrA-, uvrB- or uvrC-. Lambda uvrA+ was found to transduce strains carrying uvrA- but not those carrying uvrB- or uvrC-, to normal ultraviolet resistance. Similarly, lambdauvrB+ and lambdauvrC+ were found to complement only the corresponding uvr- allele. The lambda transducing phages were co-transduced with gal+ by P1 phage into lysogenic gal- recipients, and presumably were integrated at the normal prophage site.

Alleles↗
PubMed1977

Isolation and genetic characterization of alcohol dehydrogenase thermostability variants occurring in natural populations of Drosophila melanogaster.

Drosophila melanogaster collected from natural populations were examined fo thermostability variants within electrophoretic mobility classes of two enzymes. In alcohol dehydrogenases, two discrete forms of the "slow" allozyme and three discrete forms of the "fast" allozyme were revealed by postelectrophoretic treatments ranging from 15 sec at 40 C to 40 sec at 43 C. All variants have been mapped to within 0.7 unit of the Adh locus. Results of a geographic survey indicate that two alleles giving rise to fast-moderate and slow-moderate allozymes are common everywhere; other variants have a collective frequency ranging from 0% to 7%. In a test of the possibility that the rare Adh alleles could be generated by intragenic recombination between the two common alleles, electrophoresis and heat treatment of progeny recombinant for flanking markers of Adh revealed no new allozymes. Among 27 stocks containing slow alpha-glycerophosphate dehydrogenase allozymes and 109 fast stocks, heat treatments revealed no additional variation.

Alcohol Oxidoreductases↗
PubMed2025

Molecular characterization of drug-resistance genes and dynamics of multidrug-resistant Salmonella spp. in waterfowl: a pre- and post-antibiotic ban surveillance in Guangdong, China from 2013 to 2023.

BACKGROUND: Multidrug-Resistant Organism (MDRO) refers to bacteria that are Resistant to three or more types of antibiotics in clinical use. The global health threat posed by multidrug-resistant (MDR) bacterial pathogens and their cross-species transmission necessitates rigorous Surveillance. This urgency is amplified in China where antibiotic growth promoters were widely used in animal husbandry until the 2020 implementation of Announcement No. 194 launched by Ministry of Agriculture and Rural Affairs (Announcement 194), banning non-therapeutic antibiotics in feed. This study conducted a decade long investigation on the correlation between antimicrobial resistance (AMR) phenotypes and genetic determinants in 314 Salmonella isolates collected from waterfowl across Guangdong Province, China, utilizing disk diffusion (Kirby-Bauer method) and PCR-based detection of antibiotic resistance genes (ARGs). The study period covered the antibiotic policy transition in China, specifically encompassing the pre-ban (2013-2019) and post-ban (2020-2023) phases of the nationwide prohibition on growth-promoting antimicrobials in animal feed. METHODS: Antimicrobial Susceptibility profiles against 16 agents were determined via Kirby-Bauer testing, while PCR amplification targeted 20 ARGs. Statistical analyses evaluated phenotype-genotype correlations using Pearson`s chi-square test. RESULTS: Surveillance revealed escalating resistance rates annually. Highest resistance prevalence was observed against &#x3b2;-lactams and amphenicols (92.25%), whereas amikacin exhibited the lowest resistance rate (9.55%). MDR prevalence reached 87.23%, with the AMP-CAZ-GEN-FFC-TET resistance profile predominating (51.6% of isolates). Genetic analysis identified 3 to 16 ARGs per isolate was harboring, with blaTEM demonstrating the highest detection frequency (90.76%). Significant phenotype-genotype correlations (p&#x2009;<&#x2009;0.05) were observed for 13 genes: blaCTX-M, blaTEM, blaOXA, aacC2, aph(3')-I, aac(3)-IV, aadA1, qnrS, qnrA, clmA, floR, sulII, tetA. Notably, significant declines in resistance to aminoglycosides (e.g., gentamicin from 71.7 to 3.5%) and florfenicol (from 81.1 to 9.6%) were observed after China's 2019 antibiotic ban policy (p&#x2009;<&#x2009;0.001), underscoring the impact of targeted antimicrobial stewardship in avian husbandry. CONCLUSIONS: Analysis of 314 waterfowl Salmonella strains revealed severe multidrug resistance (MDR) and diverse resistance genes (DRGs), with 13 DRGs linked to resistance. China's antibiotic ban reduced targeted resistance, but MDR persists alarmingly via acquired DRGs and adaptation. Continued enforcement may lower aminoglycoside/phenicol resistance, but &#x3b2;-lactam resistance will likely endure, worsened by transcontinental blaCTX-M spread. Critically, plasmid co-selection threatens to amplify MDR, demanding genomic surveillance. Mitigation requires boosting policy compliance, developing non-antibiotic therapies, mapping mutations, establishing cross-species barriers, and prioritizing One Health interventions to block resistance spread.

China↗