Exposure to Folate Receptor Alpha Antibodies during Gestation and Weaning Leads to Severe Behavioral Deficits in Rats: A Pilot Study

The central nervous system continues to develop during gestation and after birth, and folate is an essential nutrient in this process. Folate deficiency and folate receptor alpha autoantibodies (FRα-AuAb) have been associated with pregnancy-related complications and neurodevelopmental disorders. In this pilot study, we investigated the effect of exposure to FRα antibodies (Ab) during gestation (GST), the pre-weaning (PRW), and the post weaning (POW) periods on learning and behavior in adulthood in a rat model. In the open field test and novel object recognition task, which examine locomotor activity and anxiety-like behavior, deficits in rats exposed to Ab during gestation and pre-weaning (GST+PRW) included more time spent in the periphery or corner areas, less time in the central area, frequent self-grooming akin to stereotypy, and longer time to explore a novel object compared to a control group; these are all indicative of increased levels of anxiety. In the place avoidance tasks that assess learning and spatial memory formation, only 30% of GST+PRW rats were able to learn the passive place avoidance task. None of these rats learned the active place avoidance task indicating severe learning deficits and cognitive impairment. Similar but less severe deficits were observed in rats exposed to Ab during GST alone or only during the PRW period, suggesting the extreme sensitivity of the fetal as well as the neonatal rat brain to the deleterious effects of exposure to Ab during this period. Behavioral deficits were not seen in rats exposed to antibody post weaning. These observations have implications in the pathology of FRα-AuAb associated with neural tube defect pregnancy, preterm birth and neurodevelopmental disorders including autism.     

Antisense RNA strategies for metabolic engineering of Clostridium acetobutylicum

We examined the effectiveness of antisense RNA (as RNA) strategies for metabolic engineering of Clostridium acetobutylicum. Strain ATCC 824(pRD4) was developed to produce a 102-nucleotide asRNA with 87% complementarity to the butyrate kinase (BK) gene. Strain ATCC 824(pRD4) exhibited 85 to 90% lower BK and acetate kinase specific activities than the control strain. Strain ATCC 824(pRD4) also exhibited 45 to 50% lower phosphotransbutyrylase (PTB) and phosphotransacetylase specific activities than the control strain. This strain exhibited earlier induction of solventogenesis, which resulted in 50 and 35% higher final concentrations of acetone and butanol, respectively, than the concentrations in the control. Strain ATCC 824(pRD1) was developed to putatively produce a 698-nucleotide asRNA with 96% complementarity to the PTB gene. Strain ATCC 824(pRD1) exhibited 70 and 80% lower PTB and BK activities, respectively, than the control exhibited. It also exhibited 300% higher levels of a lactate dehydrogenase activity than the control exhibited. The growth yields of ATCC 824(pRD1) were 28% less than the growth yields of the control. While the levels of acids were not affected in ATCC 824(pRD1) fermentations, the acetone and butanol concentrations were 96 and 75% lower, respectively, than the concentrations in the control fermentations. The lower level of solvent production by ATCC 824(pRD1) was compensated for by approximately 100-fold higher levels of lactate production. The lack of any significant impact on butyrate formation fluxes by the lower PTB and BK levels suggests that butyrate formation fluxes are not controlled by the levels of the butyrate formation enzymes.     

P‐4TRANSFORMATION ZONE COMPONENT IN LIQUID BASED CERVICAL CYTOLOGY

Introduction: Quality assurance guidelines for the UK cervical screening programme recommend that more than 80% of cervical samples from women aged 20–50 years should contain adequate numbers of Transformation zone (TZ) cells i.e. 10 or more endocervical or squamous metaplastic cells. This study was conducted to assess the frequency of TZ component in Liquid Based Cytology (LBC) both for ThinPrep (TP) and SurePath (SP) LBC. Also to assess the degree to which this is recorded by individual screeners and to determine the percentage of samples with evidence of TZ component for the different smear takers. Method: All LBC cervical specimens received at a tertiary cytology centre in the year 2004 from women aged 20–50 years were included in the study. Evidence of TZ sampling was recorded as: TP = TZ present (10 or more TZ cells)TA = TZ absentTS = TZ scanty (less than 10 TZ cells)TN = atrophic smears, TZ cells not recognisable Results: The total number of LBC cervical cases was 7445. TP = 4300 (mostly primary care) and SP = 3145 (mostly colposcopy). Overall TZ sampling rate in LBC was 82%. TP = 77.17%; SP = 88.24%. When scanty TZ was included, the standard was met for both systems (TP = 93.7%; SP = 88.24%). Presence/absence of TZ component was recorded in 6370 cases (85.1%); range 0%–97.79%. 56.7% of smear takers achieved the minimum standard for TZ sampling. Discussion: The percentage of ThinPrep samples containing adequate TZ cells was 77.17% compared to SurePath, which was 88.24%. This may be due to different patient populations i.e. primary care versus colposcopy. Screeners recorded TZ sampling in approximately 85% of samples. 56.7% of smear takers met the standard for TZ sampling.     

Maternal undernutrition inhibits angiogenesis in the offspring: a potential mechanism of programmed hypertension

The underlying etiology of many chronic diseases such as hypertension and diabetes has been traced to the in utero environment. Our interest has focused on determining the mechanism of programmed hypertension. In our rodent model of 50% maternal food restriction (MFR) from day 10 of gestation to term, the offspring develop hypertension as adults. We hypothesized that maternal undernutrition inhibits angiogenesis such that the neonate is endowed with fewer microvessels, increasing their susceptibility to develop hypertension as adults. We found significantly reduced number of mesenteric branching and renal medullary microvessels in the 1-day-old MFR newborns. Endothelial cells from MFR offspring generated shorter neovessels in culture compared with controls. The inhibition of angiogenesis was associated with a significant decrease in VEGF protein expression in mesenteric microvessels and aortas in 1-day-old offspring. However, in adulthood there was a marked increase in VEGF expression in both vessel types. The expression of endothelial nitric oxide synthase protein was also found to be increased in both renal and mesenteric microvessels and in aortas in the 1-day-old MFR offspring. These results suggest that MFR results in inhibition of VEGF expression in microvascular and aortic endothelial cells early in life, resulting in decreased angiogenesis and increased peripheral vascular resistance, both of which may contribute to offspring hypertension.     

Zinc lowers amyloid-beta toxicity by selectively precipitating aggregation intermediates

Soluble amyloid-beta (Abeta) aggregates are suspected to play a major role in Alzheimer's disease. Zn2+ at a concentration of a few micromolar, which is too dilute to affect the precipitation equilibrium of Abeta, can destabilize these aggregates [Garai, K., Sengupta, P., Sahoo, B., and Maiti, S. (2006) Biochem. Biophys. Res. Commun. 345, 210-215]. Here we investigate the nature of these aggregates in the context of the precipitation pathway, the mechanism underlying their destabilization, and the biological consequences of this destabilization. We show that the larger soluble aggregates (size >10 nm) form only in supersaturated Abeta solutions, implying that they are intermediates in the pathway toward fibril formation. We also show that Zn2+ destabilizes these intermediates by accelerating their aggregation kinetics. The resulting change in the size distribution of the Abeta solution is sufficient to eliminate its toxicity to cultured mammalian neurons. Our results provide an explanation for the existing observations that Zn2+ at a concentration of a few micromolar significantly reduces Abeta toxicity.     

Measurement of biodegradability parameters for single unsubstituted and methylated polycyclic aromatic hydrocarbons in liquid bacterial suspensions

Substrate depletion experiments were conducted to characterize aerobic biodegradation of 20 single polycyclic aromatic hydrocarbons (PAHs) by induced Sphingomonas paucimobilis strain EPA505 in liquid suspensions. PAHs consisted of low molecular weight, unsubstituted, and methyl-substituted homologs. A material balance equation containing the Andrews kinetic model, an extension of the Monod model accounting for substrate inhibition, was numerically fitted to batch depletion data to estimate extant kinetic parameters including the maximal specific uptake rates, q(max), the affinity coefficients, K(S), and the substrate inhibition coefficients, K(I). Strain EPA505 degraded all PAHs tested. Applied kinetic models adequately simulated experimental data. A cell proliferation assay involving reduction of the tetrazolium dye WST-1 was used to evaluate the ability of strain EPA505 to utilize individual PAHs as sole energy and carbon sources. Of the 22 PAHs tested, 9 supported bacterial growth. Evaluation of the biokinetic data showed that q(max) correlated highly with transmembrane flux as theoretically estimated by a diffusion model, pointing to transmembrane transport as a potential rate-determining process. The biodegradability data generated in this study is essential for the development of quantitative structure-activity relationships (QSARs) for biodegradability and for modeling biodegradation of simple PAH mixtures.     

Evolution can favor antagonistic epistasis

The accumulation of deleterious mutations plays a major role in evolution, and key to this are the interactions between their fitness effects, known as epistasis. Whether mutations tend to interact synergistically (with multiple mutations being more deleterious than would be expected from their individual fitness effects) or antagonistically is important for a variety of evolutionary questions, particularly the evolution of sex. Unfortunately, the experimental evidence on the prevalence and strength of epistasis is mixed and inconclusive. Here we study theoretically whether synergistic or antagonistic epistasis is likely to be favored by evolution and by how much. We find that in the presence of recombination, evolution favors less synergistic or more antagonistic epistasis whenever mutations that change the epistasis in this direction are possible. This is because evolution favors increased buffering against the effects of deleterious mutations. This suggests that we should not expect synergistic epistasis to be widespread in nature and hence that the mutational deterministic hypothesis for the advantage of sex may not apply widely.