Alkaloids from Oriciopsis glaberrima Engl. (Rutaceae)

Two alkaloid derivatives, oriciacridone A and B, were isolated from the stem bark of Oriciopsis glaberrima (Rutaceae). The structures were elucidated by a detailed spectroscopic analysis. The extract exhibited in vitro significant antimicrobial activity against a range of micro-organisms.     

FSH directly regulates bone mass

Postmenopausal osteoporosis, a global public health problem, has for decades been attributed solely to declining estrogen levels. Although FSH levels rise sharply in parallel, a direct effect of FSH on the skeleton has never been explored. We show that FSH is required for hypogonadal bone loss. Neither FSHbeta nor FSH receptor (FSHR) null mice have bone loss despite severe hypogonadism. Bone mass is increased and osteoclastic resorption is decreased in haploinsufficient FSHbeta+/- mice with normal ovarian function, suggesting that the skeletal action of FSH is estrogen independent. Osteoclasts and their precursors possess G(i2alpha)-coupled FSHRs that activate MEK/Erk, NF-kappaB, and Akt to result in enhanced osteoclast formation and function. We suggest that high circulating FSH causes hypogonadal bone loss.     

Hydrogen peroxide commences copper induced DNA damage isolated from human blood: in vitro study

The present study revealed the damaging effects of copper and hydrogen peroxide on DNA isolated from human blood in in vitro. Ultra violet spectral studies showed that copper and H2O2 alone (at 20 mM) caused destabilization of DNA structure. Notwithstanding, the effect was more prominent in combination of copper and H2O2. Further, agarose gel electrophoretic studies revealed that neither copper nor H2O2 alone had DNA fragmentation (up to 40 mM concentration), while copper and H2O2 together caused massive DNA fragmentation even at lower concentrations (4 mM copper + 4 mM H2O2). Therefore, it was concluded from the present study that the observed destabilization of DNA associated with alterations in configuration and subsequently massive DNA fragmentation was in response to copper and H2O2. Further, fluorescence spectroscopy and TUNNEL assay will address destabilization and fragmentation of naked DNA more precisely.     

Pol β associated complex and base excision repair factors in mouse fibroblasts

During mammalian base excision repair (BER) of lesion-containing DNA, it is proposed that toxic strand-break intermediates generated throughout the pathway are sequestered and passed from one step to the next until repair is complete. This stepwise process is termed substrate channeling. A working model evaluated here is that a complex of BER factors may facilitate the BER process. FLAG-tagged DNA polymerase (pol) β was expressed in mouse fibroblasts carrying a deletion in the endogenous pol β gene, and the cell extract was subjected to an ‘affinity-capture’ procedure using anti-FLAG antibody. The pol β affinity-capture fraction (ACF) was found to contain several BER factors including polymerase-1, X-ray cross-complementing factor1-DNA ligase III and enzymes involved in processing 3′-blocked ends of BER intermediates, e.g. polynucleotide kinase and tyrosyl-DNA phosphodiesterase 1. In contrast, DNA glycosylases, apurinic/aprymidinic endonuclease 1 and flap endonuclease 1 and several other factors involved in BER were not present. Some of the BER factors in the pol β ACF were in a multi-protein complex as observed by sucrose gradient centrifugation. The pol β ACF was capable of substrate channeling for steps in vitro BER and was proficient in in vitro repair of substrates mimicking a 3′-blocked topoisomerase I covalent intermediate or an oxidative stress-induced 3′-blocked intermediate.     

Single-nucleotide base excision repair DNA polymerase activity in C. elegans in the absence of DNA polymerase β

The base excision DNA repair (BER) pathway known to occur in Caenorhabditis elegans has not been well characterized. Even less is known about the DNA polymerase (pol) requirement for the gap-filling step during BER. We now report on characterization of in vitro uracil-DNA initiated BER in C. elegans. The results revealed single-nucleotide (SN) gap-filling DNA polymerase activity and complete BER. The gap-filling polymerase activity was not due to a DNA polymerase β (pol β) homolog, or to another X-family polymerase, since computer-based sequence analyses of the C. elegans genome failed to show a match for a pol β-like gene or other X-family polymerases. Activity gel analysis confirmed the absence of pol β in the C. elegans extract. BER gap-filling polymerase activity was partially inhibited by both dideoxynucleotide and aphidicolin. The results are consistent with a combination of both replicative polymerase(s) and lesion bypass/BER polymerase pol θ contributing to the BER gap-filling synthesis. Involvement of pol θ was confirmed in experiments with extract from pol θ null animals. The presence of the SN BER in C. elegans is supported by these results, despite the absence of a pol β-like enzyme or other X-family polymerase.     

Diet among people in the Terai region of Nepal, an area of micronutrient deficiency

In the Terai region, despite its ecological richness, the people have long suffered from a deficiency of micronutrients such as vitamin A, iron and zinc. The aim of this study was to investigate dietary and nutritional intakes among people in the Terai region of Nepal. The results were compared by sex and ethnicity. Food consumption surveys (one-day weighed records) were conducted among 114 people (55 Mushar and 59 Tharu). Nutritional intakes were calculated using Nepali food composition and other tables. The diet in the Terai region was characterized by a large amount of rice consumed with a tiny amount of curry or dal as a side dish. Intakes of vitamin A, iron, riboflavin and selenium were less than 50% of the recommended daily allowance irrespective of ethnicity or sex (with the exception of iron intake among Tharu males). Intakes of thiamine, riboflavin, niacin, phosphorus and zinc were higher among the Tharu than the Mushar, while intakes of selenium and iodine were higher among the Mushar than the Tharu. The nutritional significance of these differences was slight. Protein intake (per kg body weight) was lower in females than in males, while the energy-adjusted micronutrient intakes did not differ by sex. Intakes of vitamin A, iron, riboflavin and selenium were deficient among the participants. Intervention projects such as the introduction of kitchen gardens or fish farming may be effective, but will increase the degree of inequality between the two ethnic groups.     

αA-Crystallin and αB-Crystallin Reside in Separate Subcellular Compartments in the Developing Ocular Lens

αA-Crystallin (αA) and αB-crystallin (αB), the two prominent members of the small heat shock family of proteins are considered to be two subunits of one multimeric protein, α-crystallin, within the ocular lens. Outside of the ocular lens, however, αA and αB are known to be two independent proteins, with mutually exclusive expression in many tissues. This dichotomous view is buoyed by the high expression of αA and αB in the lens and their co-fractionation from lens extracts as one multimeric entity, α-crystallin. To understand the biological function(s) of each of these two proteins, it is important to investigate the biological basis of this perceived dichotomy; in this report, we address the question whether αA and αB exist as independent proteins in the ocular lens. Discontinuous sucrose density gradient fractionation and immunoconfocal localization reveal that in early developing rat lens αA is a membrane-associated small heat shock protein similar to αB but with remarkable differences. Employing an established protocol, we demonstrate that αB predominantly sediments with rough endoplasmic reticulum, whereas αA fractionates with smooth membranes. These biochemical observations were corroborated with immunogold labeling and transmission electron microscopy. Importantly, in the rat heart also, which does not contain αA, αB fractionates with rough endoplasmic reticulum, suggesting that αA has no influence on the distribution of αB. These data demonstrate presence of αA and αB in two separate subcellular membrane compartments, pointing to their independent existence in the developing ocular lens.