Folate deficiency regulates expression of DNA polymerase β in response to oxidative stress

Folate deficiency has been shown to influence carcinogenesis by creating an imbalance in the base excision repair (BER) pathway, affecting BER homeostasis. The inability to mount a BER response to oxidative stress in a folate-deficient environment results in the accumulation of DNA repair intermediates, i.e., DNA strand breaks. Our data indicate that upregulation of β-pol expression in response to oxidative stress is inhibited by folate deficiency at the level of gene expression. Alteration in the expression of β-pol in a folate-deficient environment is not due to epigenetic changes in the core promoter of the β-pol gene, i.e., the CpG islands within the β-pol promoter remain unmethylated in the presence or absence of folate. However, the promoter analysis studies show a differential binding of regulatory factors to the -36 to -7 region (the folic acid-response region, FARR) within the core promoter of β-pol. Moreover, we observe a tight correlation between the level of binding of regulatory factors with the FARR and inhibition of β-pol expression. Based on these findings, we propose that folate deficiency results in an upregulation/stability of negative regulatory factors interacting with FARR, repressing the upregulation of the β-pol gene in response to oxidative stress.     

Adverse effects on macrophage lipid transport and survival by high density lipoprotein from patients with coronary heart disease

High density lipoprotein (HDL)–macrophage interactions have the potential to modulate macrophage function in a beneficial way to prevent the development of lipid‐loaded foam cell formation in atherosclerosis. Although HDL is atheroprotective, it can become dysfunctional in chronic inflammatory conditions and increase cardiovascular risk. Here, we examined the effect of dysfunctional‐HDL from patients with coronary artery disease, on macrophage function in comparison to functional‐HDL from controls. Exposure of macrophages to dysfunctional‐HDL for 24 h resulted significant increase in cellular oxidative stress, cholesterol, and cytotoxicity. It also stimulated mitochondrial membrane depolarization, DNA damage, apoptosis, and cleavage of poly (ADP‐ribose) polymerase, which are characteristics of proapoptotic pathways. In contrast, functional‐HDL treatment maintained cholesterol homeostasis, essential membrane potential, DNA integrity, and cell survival. These results demonstrate that HDL from coronary artery disease (CAD) patient promotes proatherogenic effects that in turn trigger macrophage apoptosis, an important feature in atherogenesis and thereby providing new insight in our understanding of the atherogenic mechanisms.     

Antagonistic potential of native strain Streptomyces aurantiogriseus VSMGT1014 against sheath blight of rice disease

A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, India, among which 57 showed antagonistic activity towards Rhizoctonia solani, which is sheath blight (ShB) pathogen of rice and other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata with a variable zone of inhibition. Potential actinomycete strain VSMGT1014 was identified as Streptomyces aurantiogriseus VSMGT1014 based on the morphological, physiological, biochemical and 16S rRNA sequence analysis. The strain VSMGT1014 produced lytic enzymes, secondary metabolites, siderophore, volatile substance and indole acetic acid. Crude metabolites of VSMGT1014 showed activity against R. solani at 5 µg ml^?1; however, the prominent inhibition zone was observed from 40 to 100 µg ml^?1. Reduced lesion heights observed in culture, cells-free filtrate, crude metabolites and carbendazim on challenge with pathogen in the detached leaf assay. The high content screening test clearly indicated denucleation of R. solani at 5 µg ml^?1 treatment of crude metabolite and carbendazim respectively. The results conclude that strain VSMGT1014 was found to be a potential candidate for the control of ShB of rice as a bio fungicide.     

Accounting for Limited Detection Efficiency and Localization Precision in Cluster Analysis in Single Molecule Localization Microscopy

Single Molecule Localization Microscopy techniques like PhotoActivated Localization Microscopy, with their sub-diffraction limit spatial resolution, have been popularly used to characterize the spatial organization of membrane proteins, by means of quantitative cluster analysis. However, such quantitative studies remain challenged by the techniques’ inherent sources of errors such as a limited detection efficiency of less than 60%, due to incomplete photo-conversion, and a limited localization precision in the range of 10 – 30nm, varying across the detected molecules, mainly depending on the number of photons collected from each. We provide analytical methods to estimate the effect of these errors in cluster analysis and to correct for them. These methods, based on the Ripley’s L(r) – r or Pair Correlation Function popularly used by the community, can facilitate potentially breakthrough results in quantitative biology by providing a more accurate and precise quantification of protein spatial organization.     

A Note on Life Table Construction

In this article a modification to the CHIANG'S method of construction of the current life table is presented by using a new set of estimates of n^ax, derived under certain simplified assumptions.     

Circadian and Ultradian Variations in the Plasma Level of Maturational Gonadotropin (GTH II) in the Indian Catfish,Clarias batrachus

Analysis of changes in the plasma levels of GTH II over a 24-h day/night cycle revealed statistically significant circadian or ultradian variation or both in its circulating level during the gonadally active months of the reproductive cycle. The 24-h average and amplitude of circadian or ultradian rhythm in GTH II increased with the advancement of ovarian development and maturation. In April, a single peak in GTH II level was noticed in the night at 20.6 h. In contrast, in May, June and July a biphasic pattern (ultradian rhythm) was noticed with two characteristic peaks, one in the photophase and the other in the scotophase. In addition, in May a statistically significant circadian rhythm in plasma GTH II was validated with a peak located at 20.1 h. These rhythms seem to have physiological significance. The ultradian rhythm with two peaks during the reproductively active phase appears to provide a suitable physiological milieu for the temporally different yet synchronous population of oocytes for the secretion of steroids. Thus, the observed temporal organization in GTH II may have physiological consequences leading to accomplishment of reproductive process at appropriate time of the year.     

Immunomodulatory effect of probiotics enriched diets on Uronema marinum infected olive flounder

The effect of five probiotics, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus sakei, Bacillus subtilis, and Saccharomyces cerevisiae as individual and mixed enriched diet on the seasonal prevalence, activity and intensity of Uronema marinum infection in olive flounder Paralichthys olivaceus is reported. The growth performance, feed efficiency, blood biochemistry, survival rate, and non-specific immune response of U. marinum infected olive flounder on week 0, 1, 2, 4, 6, and 8 were quantified. The prevalence and infection intensity reached a peak from June to December and then it declined from December to March. The scuticocidal activity in the serum was significantly higher when fed with L. plantarum, L. acidophilus, and S. cerevisiae diets on weeks 2-8. All enriched diets significantly enhanced the weight gain significantly between week 6 and 8; the feed efficiency registered a significantly increase from week 4 to 8 when compared to infected fish fed with control diet. Infected fish fed with L. plantarum-supplemented diet had higher survival rate than with other enriched diets. The serum aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels significantly increased when fed with L. plantarum, L. acidophilus or S. cerevisiae-supplemented diet. Total protein (TP) and glucose (GLU) level significantly increased with any enriched diet from week 4 to 8. The superoxide anion production and serum lysozyme activity registered a significant increase when fed with L. plantarum, L. acidophilus, and S. cerevisiae-supplemented diet from week 4-8. The present study concludes that L. plantarum, L. acidophilus, and S. cerevisiae-supplemented diets act as immunostimulants enhancing the growth, feed efficiency, blood biochemistry, survival rate, and non-specific immune response in U. marinum infected olive flounder.