T-DNA integration: a mode of illegitimate recombination in plants.

Transferred DNA (T-DNA) insertions of Agrobacterium gene fusion vectors and corresponding insertional target sites were isolated from transgenic and wild type Arabidopsis thaliana plants. Nucleotide sequence comparison of wild type and T-DNA-tagged genomic loci showed that T-DNA integration resulted in target site deletions of 29-73 bp. In those cases where integrated T-DNA segments turned out to be smaller than canonical ones, the break-points of target deletions and T-DNA insertions overlapped and consisted of 5-7 identical nucleotides. Formation of precise junctions at the right T-DNA border, and DNA sequence homology between the left termini of T-DNA segments and break-points of target deletions were observed in those cases where full-length canonical T-DNA inserts were very precisely replacing plant target DNA sequences. Aberrant junctions were observed in those transformants where termini of T-DNA segments showed no homology to break-points of target sequence deletions. Homology between short segments within target sites and T-DNA, as well as conversion and duplication of DNA sequences at junctions, suggests that T-DNA integration results from illegitimate recombination. The data suggest that while the left T-DNA terminus and both target termini participate in partial pairing and DNA repair, the right T-DNA terminus plays an essential role in the recognition of the target and in the formation of a primary synapsis during integration.     

Detoxification of ochratoxin A,a food contaminant: Prevention of growth of Aspergillus ochraceus and its production of ochratoxin A

The toxicity of ochratoxin A (OTA), a mycotoxin produced by fungi ofAspergillus orPenicillium genera is now well documented. Its nephrotoxicity, immunosuppression, teratogenicity, and carcinogenicity have been widely studied. Physical and biochemical methods have been studied to prevent these toxinogenicAspergillus andPenicillium from producing OTA, and/or to destroy the mycotoxin when already produced in a liquid or a solid medium. Repeated freezing at ? 20?C and thawing at + 26?C aleatory reduce OTA production in a liquid medium. Exposure to UV B for different periods of time is efficient in preventing OTA production in a liquid medium. Gamma-irradiation from 2 to 5 kGy gives good results in preventing the production of OTA or destroying it when already produced. Carboxypeptidase is very efficient at 5 units/50 ml in a liquid medium for cleaving the OTA already produced.     

The role of fish-poultry integration on fish growth performance,yields and economic benefits among smallholder farmers in sub-Saharan Africa,Tanzania

Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growth performance, yields and economic benefits among smallholder farmers in sub-Saharan Africa, Tanzania. The study also compared phytoplankton species composition, abundance and biomass between the fish-poultry integration and non-integrated system. After 180 days of the experiment, all male O. niloticus cultured under fish-poultry integration exhibited significantly higher growth rates than those in the non-integrated system (p < 0.05). Gross fish yield (GFY), net fish yield (NFY) and net annual yields (NAY) obtained from fish-poultry integration were significantly higher than those from non-integrated system (p < 0.05). Partial enterprise budget analysis revealed that fish-poultry integration was more profitable than the non-integrated system. Moreover, fish-poultry integrated system produced significantly higher phytoplankton abundance and biomass than those from the non-integrated system. Results demonstrate that rural smallholder farmers can achieve higher growth rate, farm net yields and income by integrating all male O. niloticus with other on-farm activities than practising a stand-alone fish culture system.     

Nuclear gene trees and the phylogenetic relationships of the mangabeys (Primates: Papionini)

Phylogenetic relationships of mangabeys within the Old World monkey tribe Papionini are inferred from analyses of nuclear DNA sequences from five unlinked loci. The following conclusions are strongly supported, based on congruence among trees derived for the five separate gene regions: (1) mangabeys are polyphyletic within the Papionini; (2) Cercocebus is the sister taxon to the genus Mandrillus; and (3) Lophocebus belongs to a clade with Papio and Theropithecus, with Papio as its most likely sister taxon. Morphologically based phylogenies positing mangabey monophyly were evaluated by mapping the sequences for each locus on these trees. The data seem to fit these trees poorly in both maximum-parsimony and likelihood analyses. Incongruence among nuclear gene trees occurred in the interrelationships among Lophocebus, Papio, and Theropithecus. Several factors that may account for this incongruence are discussed, including sampling error, random lineage sorting, and introgression.      

Identification of genetic loci involved in diabetes using a rat model of depression

While diabetic patients often present with comorbid depression, the underlying mechanisms linking diabetes and depression are unknown. The Wistar Kyoto (WKY) rat is a well-known animal model of depression and stress hyperreactivity. In addition, the WKY rat is glucose intolerant and likely harbors diabetes susceptibility alleles. We conducted a quantitative trait loci (QTL) analysis in the segregating F₂ population of a WKY × Fischer 344 (F344) intercross. We previously published QTL analyses for depressive behavior and hypothalamic-pituitary-adrenal (HPA) activity in this cross. In this study we report results from the QTL analysis for multiple metabolic phenotypes, including fasting glucose, post-restraint stress glucose, postprandial glucose and insulin, and body weight. We identified multiple QTLs for each trait and many of the QTLs overlap with those previously identified using inbred models of type 2 diabetes (T2D). Significant correlations were found between metabolic traits and HPA axis measures, as well as forced swim test behavior. Several metabolic loci overlap with loci previously identified for HPA activity and forced swim behavior in this F₂ intercross, suggesting that the genetic mechanisms underlying these traits may be similar. These results indicate that WKY rats harbor diabetes susceptibility alleles and suggest that this strain may be useful for dissecting the underlying genetic mechanisms linking diabetes, HPA activity, and depression.     

Paternal Genetic Contribution Influences Fetal Vulnerability to Maternal Alcohol Consumption in a Rat Model of Fetal Alcohol Spectrum Disorder

Background

Fetal alcohol exposure causes in the offspring a collection of permanent physiological and neuropsychological deficits collectively termed Fetal Alcohol Spectrum Disorder (FASD). The timing and amount of exposure cannot fully explain the substantial variability among affected individuals, pointing to genetic influences that mediate fetal vulnerability. However, the aspects of vulnerability that depend on the mother, the father, or both, are not known.

Methodology/Principal Findings

Using the outbred Sprague-Dawley (SD) and inbred Brown Norway (BN) rat strains as well as their reciprocal crosses, we administered ethanol (E), pair-fed (PF), or control (C) diets to the pregnant dams. The dams'' plasma levels of free thyroxine (fT4), triiodothyronine (T3), free T3 (fT3), and thyroid stimulating hormone (TSH) were measured to elucidate potential differences in maternal thyroid hormonal environment, which affects specific aspects of FASD. We then compared alcohol-exposed, pair fed, and control offspring of each fetal strain on gestational day 21 (G21) to identify maternal and paternal genetic effects on bodyweight and placental weight of male and female fetuses.

Conclusions

SD and BN dams exhibited different baseline hypothalamic-pituitary-thyroid function. Moreover, the thyroid function of SD dams was more severely affected by alcohol consumption while that of BN dams was relatively resistant. This novel finding suggests that genetic differences in maternal thyroid function are one source of maternal genetic effects on fetal vulnerability to FASD. The fetal vulnerability to decreased bodyweight after alcohol exposure depended on the genetic contribution of both parents, not only maternal contribution as previously thought. In contrast, the effect of maternal alcohol consumption on placental weight was consistent and not strain-dependent. Interestingly, placental weight in fetuses with different paternal genetic contributions exhibited opposite responses to caloric restriction (pair feeding). In summary, these novel findings demonstrate both maternal and paternal genetic contributions to in utero vulnerability to alcohol, refining our understanding of the genetically-based heterogeneity seen in human FASD.     

Sexually dimorphic effects of maternal alcohol intake and adrenalectomy on left ventricular hypertrophy in rat offspring

In humans, low birth weight and increased placental weight can be associated with cardiovascular disease in adulthood. Low birth weight and increased placental size are known to occur after fetal alcohol exposure or prenatal glucocorticoid administration. Thus the effects of removing the alcohol-induced increase in maternal corticosterone by maternal adrenalectomy on predictors of cardiovascular disease in adulthood were examined in rats. Alcohol exposure of dams during the last 2 wk of gestation resulted in significantly decreased fetal weight and increased placental weight on gestational day 21. Adult female, but not male, offspring of alcohol-consuming mothers exhibited left ventricular hypertrophy. Placental 11beta-hydroxysteroid dehydrogenase-2 (11beta-HSD-2) mRNA levels, measured by Northern blot, were decreased in females but not males. Adrenalectomy of alcohol-consuming dams reversed the increase in placental weight and the decrease in female placental 11beta-HSD-2 expression and eliminated the left ventricular hypertrophy of adult female offspring. These data suggest that alcohol-induced changes in placental 11beta-HSD-2 mRNA levels and left ventricular weight are coupled in female offspring only and depend on maternal adrenal status.     

X-linked and lineage-dependent inheritance of coping responses to stress

Coping—or how one routinely deals with stress—is a complex behavioral trait with bearing on chronic disease and susceptibility to psychiatric disorders. This complexity is a result of not only underlying multigenic factors, but also important non-genetic ones. The defensive burying (DB) test, although originally developed as a test of anxiety, can accurately measure differences in coping strategies by assaying an animals behavioral response to an immediate threat with ethological validity. Using offspring derived from reciprocal crosses of two inbred rat strains differing in DB behaviors, we provide convergent phenotypic and genotypic evidence that coping styles are inherited in an X-linked fashion. We find that first-generation (F₁) males, but not females, show maternally derived coping styles, and second-generation (F₂) females, but not males, show significant differences in coping styles when separated by grandmaternal lineage. By using a linear modeling approach to account for covariate effects (sex and lineage) in QTL analysis, we map three quantitative trait loci (QTL) on the X Chromosome (Chr) (Coping-1, Approach-1, and Approach-2) associated with coping behaviors in the DB paradigm. Distinct loci were associated with different aspects of coping, and their effects were modulated by both the sex and lineage of the animals, demonstrating the power of the general linear modeling approach and the important interplay of allelic and non-allelic factors in the inheritance of coping behaviors.     

Proteomic analysis of human placental syncytiotrophoblast microvesicles in preeclampsia

Background

Placental syncytiotrophoblast microvesicles (STBM) are shed into the maternal circulation during normal pregnancy. STBM circulate in significantly increased amounts in preeclampsia (PE) and are considered to be among contributors to the exaggerated proinflammatory, procoagulant state of PE. However, protein composition of STBM in normal pregnancy and PE remains unknown. We therefore sought to determine the protein components of STBM and whether STBM protein expressions differ in preeclamptic and normal pregnancies.Patients with PE (n = 3) and normal pregnant controls (n = 6) were recruited. STBM were prepared from placental explant culture supernatant. STBM proteins were analyzed by a combination of 1D Gel-LC-MS/MS. Protein expressions levels were quantified using spectral counts and validated by immunohistochemistry.

Results

Over 400 proteins were identified in the STBM samples. Among these, 25 proteins were found to be differentially expressed in preeclampsia compared to healthy pregnant controls, including integrins, annexins and histones.

Conclusion

STBM proteins include those that are implicated in immune response, coagulation, oxidative stress, apoptosis as well as lipid metabolism pathways. Differential protein expressions of STBM suggest their pathophysiological relevance in PE.

Electronic supplementary material

The online version of this article (doi:10.1186/1559-0275-11-40) contains supplementary material, which is available to authorized users.