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PubMed2006

Basal and induced micronucleus frequencies in human lymphocytes with different GST and NAT2 genetic backgrounds.

Basal and induced frequencies of genetic damage can be modulated by different host factors, including genes involved in phase II metabolism. Since polymorphic variants in the glutathione S-transferase (GST) and N-acetyl transferase (NAT) genes have been associated with cancer risk, we explored the possible links between GSTM1, GSTP1, GSTT1 and NAT2 variants and the frequency of micronuclei (MN) in human lymphocytes. This exploratory study was carried out in 30 thyroid cancer patients, before and after receiving an average dose of 109.9+/-1.3 mCi radioactive iodine as a co-adjuvant therapy. The results indicate that none of the polymorphisms studied show any kind of association with the basal level of micronuclei. When the same patients were followed after radioiodine exposure, a significant increase in the frequency of MN was observed in practically all of them (28/30), indicating the genotoxic activity of the ionising radiation exposure. The increase in MN frequency was not associated with any of the GST polymorphisms evaluated. Nevertheless, the presence of slow acetylator phenotypes and, in particular, the presence of the NAT2*7 allele was significantly associated with a lower increase of the MN frequency after radioiodine treatment.

Adolescent↗
PubMed2002

G(z alpha) deficient mice: enzyme levels in the autonomic nervous system, neuronal survival and effect of genetic background.

Our laboratory has generated a genetically mutant mouse in which the alpha subunit of the heterotrimeric GTP binding protein, G(z) has been made dysfunctional by homologous recombination to determine its in vivo function. These animals show a characteristic failure to thrive phenotype. G(z alpha) is expressed in a variety of nervous system tissues as well as in the adrenal medulla. We therefore examined the autonomic nervous system of the G(z alpha) deficient mouse by measuring the activity of tyrosine hydroxylase and choline acetyltransferase in the superior cervical ganglia, submaxillary gland and the adrenal medulla. Preliminary results using animals of mixed BALB/c and C57BL/6 strains gave inconsistent results. Further experiments demonstrated differences in the activity of tyrosine hydroxylase and choline acetyltransferase between BALB/c and C57BL/6 mouse strains. The analysis of the pure strains showed a reduction in the size and enzyme levels of the adrenal gland and submaxillary glands of the G(z alpha) deficient mouse suggesting a role for adrenal insufficiency and/or nutritional disorders for the failure to thrive phenotype. The survival of sympathetic and sensory neurons was also examined in the G(z alpha) deficient mouse and in the presence of pertussis toxin, sympathetic but not sensory neuronal survival in G(z alpha) deficient mice was significantly attenuated. This suggests that in vivo other pertussis toxin sensitive G proteins may be recruited to compensate for the loss of G(z alpha).

Adrenal Medulla↗
PubMed1981

Immunopathology of murine infection with Schistosoma mansoni: relationship of genetic background to hepatosplenic disease and modulation.

The influence of genetic factors on the manifestations of disease associated with infection with Schistosoma mansoni (portal hypertension, liver granulomas, hepatosplenomegaly) and their modulation were studied in inbred strains of mice. Three groups were identified according to the degree of portal hypertension: high (portal venous pressure, 19.1 cm H2O: DBA/1J), intermediate (8.9-13.4 cm H2O; BALB/cJ, DBA/2J, CBA/CaJ, C3H/HeJ, and BUB/BnJ), and low responders (6.1 cm H2O; C57BL/6J). Granuloma size, organomegaly, and portal venous pressure were strain dependent and not H-2 dependent and were determined by more than one gene. Studies of schistosomiasis in the F1 generation of high and low responders indicated that more than one gene is involved. Modulation of portal venous pressure between eight and 20 weeks of infection occurred in C57BL/6J but not in BALB/cJ mice and was transferable with immune lymphoid cells. These data indicate that disease associated with infection with S. mansoni and its modulation in mice are influenced by the genetic (non-H-2) background of the host and dependent in part on cell-mediated immunity.

Animals↗
PubMed1999

Variation in short tandem repeats is deeply structured by genetic background on the human Y chromosome.

Eleven biallelic polymorphisms and seven short-tandem-repeat (STR) loci mapping on the nonrecombining portion of the human Y chromosome have been typed in men from northwestern Africa. Analysis of the biallelic markers, which represent probable unique events in human evolution, allowed us to characterize the stable backgrounds or haplogroups of Y chromosomes that prevail in this geographic region. Variation in the more rapidly mutating genetic markers (STRs) has been used both to estimate the time to the most recent common ancestor for STR variability within these stable backgrounds and to explore whether STR differentiation among haplogroups still retains information about their phylogeny. When analysis of molecular variance was used to study the apportionment of STR variation among both genetic backgrounds (i.e., those defined by haplogroups) and population backgrounds, we found STR variability to be clearly structured by haplogroups. More than 80% of the genetic variance was found among haplogroups, whereas only 3.72% of the genetic variation could be attributed to differences among populations-that is, genetic variability appears to be much more structured by lineage than by population. This was confirmed when two population samples from the Iberian Peninsula were added to the analysis. The deep structure of the genetic variation in old genealogical units (haplogroups) challenges a population-based perspective in the comprehension of human genome diversity. A population may be better understood as an association of lineages from a deep and population-independent gene genealogy, rather than as a complete evolutionary unit.

Africa, Northern↗
PubMed2005

Effects of diet and genetic background on sterol regulatory element-binding protein-1c, stearoyl-CoA desaturase 1, and the development of the metabolic syndrome.

Both environmental and genetic factors play important roles in the development of the metabolic syndrome. To elucidate how these factors interact under normal conditions, C57Bl/6 (B6) and 129S6/SvEvTac (129) mice were placed on a low-fat or high-fat diet. Over 18 weeks, the 129 strain developed features of the metabolic syndrome, notably obesity, hyperinsulinemia, and glucose intolerance only on the high-fat diet; the B6 strain on the other hand developed these features on both diets. High-fat feeding of both strains led to decreased serum triglycerides, hepatic steatosis, and hypercholesterolemia; however, B6 mice developed worse steatosis and a larger increase in LDL cholesterol. Both B6 background and high-fat feeding increased sterol regulatory element-binding protein-1c (SREBP-1c), a key regulator of lipogenic gene transcription, and its downstream targets. Stearoyl-CoA desaturase 1 (SCD1), an enzyme that regulates monounsaturated fatty acid (MUFA) synthesis, was also increased at the mRNA and enzyme activity levels by both high-fat feeding and B6 background. Furthermore, lipid analysis revealed increased hepatic triglycerides and MUFAs in B6 and high-fat-fed mice. Thus, dietary fat and genetic background act through SREBP-1c and SCD1 to affect hepatic lipid metabolism contributing to the development of the metabolic syndrome.

Animals↗
PubMed2000

Vaccination against Taenia solium cysticercosis in underfed rustic pigs of México: roles of age, genetic background and antibody response.

Vaccination of pigs of mixed genetic make-up, raised as rustically as done in rural Mexico, resulted in effective protection to experimental challenge against Taenia solium cysticercosis. Maximum protection was achieved if pigs were immunized at 70 days of age. There was large variation of viable parasite load within vaccinated pigs and controls, which is suggestive of significant genetic factors influencing susceptibility, besides immunization. Our results strengthen the advisability of pig vaccination for control of T. solium cysticercosis, since it lowers the number of viable cysticerci capable of transforming into tapeworms.

Age Factors↗
PubMed2026

Deciphering the genetic background of an industrial 2-ketogluconic acid-producing strain Pseudomonas plecoglossicida JUIM01 using whole-genome sequencing.

2-Ketogluconic acid (2KGA) is an important precursor for the food antioxidant erythorbic acid, currently produced via microbial fermentation using Pseudomonas species. To facilitate the genetic improvement of production strains, the complete genome of an industrial 2KGA producer P. plecoglossicida JUIM01 was sequenced and analyzed. The genome consists of a 5.13-Mb circular chromosome with a GC content of 63.58%, encoding 4,517 predicted proteins. Comprehensive functional annotation identified a putative global regulatory network comprising 75 core regulators, which were classified into six functionally cooperative modules, potentially governing the strain's metabolism and environmental adaptability. We further delineated the genetic determinants hypothetically linked to efficient 2KGA synthesis, including glucose metabolism, fatty acid metabolism, and the oxidative phosphorylation system. These outputs could provide the genomic resource for elucidating high productivity and robustness, and rationally engineering the high-performance chassis cells toward robust 2KGA production.

P. plecoglossicida↗
PubMed2006

The genetic background to PTSD.

Although extensive research has already been done on the genetic bases of psychiatric disorders, little is known about polygenetic influences in posttraumatic stress disorder (PTSD). This article reviews molecular genetic studies relating to PTSD that were found in a literature search in Medline, Embase and Web of Science. Association studies have investigated 8 major genotypes in connection with PTSD. They have tested hypotheses involving key candidate genes in the serotonin (5-HTT), dopamine (DRD2, DAT), glucocorticoid (GR), GABA (GABRB), apolipoprotein systems (APOE2), brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY). The studies have produced inconsistent results, many of which may be attributable to methodological shortcomings and insufficient statistical power. The complex aetiology of PTSD, for which experiencing a traumatic event forms a necessary condition, makes it difficult to identify specific genes that substantially contribute to the disorder. Gene-finding strategies are difficult to apply. Interactions between different genes and between them and the environment probably make certain people vulnerable to developing PTSD. Gene-environmental studies are needed that focus more narrowly on specific, distinct endophenotypes and on influences from environmental factors.

Apolipoproteins↗
PubMed2005

Genetic background influences cortical bone response to ovariectomy.

UNLABELLED: Peak bone mass is genetically determined, but little is known about the heritability of bone loss. Inbred mice were ovariectomized at 16 weeks of age and killed at three time-points after surgery. We found that the variation in estrogen deficit-related cortical bone loss is genetically determined. INTRODUCTION: Variability in adult bone morphology and composition among three inbred mouse strains-A/J, C57BL/6J (B6), and C3H/HeJ (C3H)-suggests that they gain bone in different ways during growth. In this study, we tested the hypothesis that these strains would also lose bone differently after estrogen deprivation. MATERIALS AND METHODS: Female A/J, B6, and C3H mice (N = 70/strain) were either ovariectomized (OVX) or sham-operated at 16 weeks of age and killed at 4, 8, and 16 weeks after surgery. Cortical bone histomorphometry was performed on right femoral mid-diaphyseal cross-sections. Mechanical properties were determined by loading left femoral mid-diaphyses to failure in four-point bending. RESULTS: Both OVX-A/J and OVX-B6 mice showed a 7-8% decrease in cortical area and width because of an 8-10% marrow expansion at 16 weeks after OVX. This bone loss did not affect mechanical properties in OVX-A/J femurs, but maximum load and stiffness in OVX-B6 decreased slightly (9%) at 4 and 8 weeks, and markedly (14-19%) at 16 weeks after OVX. In contrast, OVX-C3H showed a significant decrease in cortical area and width (6-7%) at 4 weeks after OVX and a slight decrease in the subperiosteal area (4%) at 8 weeks after OVX, although marrow area remained unchanged. Surprisingly, intracortical resorption spaces, which were present in sham-C3H mice, were greatly increased (+195%) in OVX-C3H mice at 8 weeks after OVX. Bone strength and stiffness in OVX-C3H mice decreased markedly (12-14%) at 4 weeks but slightly (8-10%) at 8 weeks after OVX. All indices except intracortical pore area in OVX-C3H mice returned to sham levels at 16 weeks after OVX. CONCLUSIONS: The magnitude, timing, and location of cortical bone loss after OVX varied significantly among A/J, B6, and C3H mice. The subsequent changes in mechanical properties after OVX depended on the variable bone patterns as well as the size and shape of the adult bone. Our results suggest that patterns of estrogen deficit-associated cortical bone loss are genetically determined.

Animals↗
PubMed2003

[Formation of congenital defects during ocular development. II. Genetic background of oculogenesis and developmental birth defects].

The course of oculogenesis is genetically controlled by genes, that are selectively expressed in the developing eye. Many of them, first recognized in studies on model animals, such as fruit fly (Drosophila melanogaster) proved, that they play similar roles in humans. The crucial role in cascade of genetic control of oculogenesis plays a system of genes PAX6-EYA1/SIX3-DACH1. In this work there are described also other genes, that form a network of interactions and regulations, such as: BMP4, BMP7, OPTX2, SOX1, PAX2, PITX2, PAX3, CHX10 and other genes. Describing function of each gene, author presented simultaneously all known congenital defects and syndromes, that are caused by mutations of above mentioned genes, such as: aniridia, anophthalmia, Peters anomaly and others.

Animals↗
PubMed2001

Influence of genetic background and heterozygosity on meiotic recombination in Arabidopsis thaliana.

Plant breeding relies on genetic variability generated by meiotic recombination. Control of recombination frequencies is not yet possible, but would significantly extend the options for plant-breeding strategies. A prerequisite would be variability of recombination frequencies. In this study, 15 transgenic kanamycin (KR) and hygromycin (HR) resistance gene insertions mapping to the five Arabidopsis thaliana chromosomes were used as genetic markers. Recombination frequencies were determined from the frequencies of resistance phenotypes within populations segregating for linked KR and HR markers. Recombination frequencies of marker pairs were compared among these four ecotypes, among F1s in both reciprocal forms derived from these ecotypes, and between F1s and their parent lines. On average, the recombination frequencies in F1 crosses were substantially higher (up to 2-fold) than in the homozygous parental ecotypes. A strong negative correlation between genetic similarities of ecotypes and recombination frequencies was detected for two adjacent marker pairs located on the long arm of chromosome 3, but not for marker pairs in other genomic regions. Our results suggest that heterozygosity influences recombination in plant breeding, and cannot be ignored in genetic mapping of genomes.

Arabidopsis↗