Kinetic Enrichment of 34S during Proteobacterial Thiosulfate Oxidation and the Conserved Role of SoxB in S-S Bond Breaking

During chemolithoautotrophic thiosulfate oxidation, the phylogenetically diverged proteobacteria Paracoccus pantotrophus, Tetrathiobacter kashmirensis, and Thiomicrospira crunogena rendered steady enrichment of ³⁴S in the end product sulfate, with overall fractionation ranging between −4.6‰ and +5.8‰. The fractionation kinetics of T. crunogena was essentially similar to that of P. pantotrophus, albeit the former had a slightly higher magnitude and rate of ³⁴S enrichment. In the case of T. kashmirensis, the only significant departure of its fractionation curve from that of P. pantotrophus was observed during the first 36 h of thiosulfate-dependent growth, in the course of which tetrathionate intermediate formation is completed and sulfate production starts. The almost-identical ³⁴S enrichment rates observed during the peak sulfate-producing stage of all three processes indicated the potential involvement of identical S-S bond-breaking enzymes. Concurrent proteomic analyses detected the hydrolase SoxB (which is known to cleave terminal sulfone groups from SoxYZ-bound cysteine S-thiosulfonates, as well as cysteine S-sulfonates, in P. pantotrophus) in the actively sulfate-producing cells of all three species. The inducible expression of soxB during tetrathionate oxidation, as well as the second leg of thiosulfate oxidation, by T. kashmirensis is significant because the current Sox pathway does not accommodate tetrathionate as one of its substrates. Notably, however, no other Sox protein except SoxB could be detected upon matrix-assisted laser desorption ionization mass spectrometry analysis of all such T. kashmirensis proteins as appeared to be thiosulfate inducible in 2-dimensional gel electrophoresis. Instead, several other redox proteins were found to be at least 2-fold overexpressed during thiosulfate- or tetrathionate-dependent growth, thereby indicating that there is more to tetrathionate oxidation than SoxB alone.     

Isolation and characterization of a novel DNA methyltransferase complex linking DNMT3B with components of the mitotic chromosome condensation machinery

Proper patterns of genome-wide DNA methylation, mediated by DNA methyltransferases DNMT1, -3A and -3B, are essential for embryonic development and genomic stability in mammalian cells. The de novo DNA methyltransferase DNMT3B is of particular interest because it is frequently overexpressed in tumor cells and is mutated in immunodeficiency, centromere instability and facial anomalies (ICF) syndrome. In order to gain a better understanding of DNMT3B, in terms of the targeting of its methylation activity and its role in genome stability, we biochemically purified endogenous DNMT3B from HeLa cells. DNMT3B co-purifies and interacts, both in vivo and in vitro, with several components of the condensin complex (hCAP-C, hCAP-E and hCAP-G) and KIF4A. Condensin mediates genome-wide chromosome condensation at the onset of mitosis and is critical for proper segregation of sister chromatids. KIF4A is proposed to be a motor protein carrying DNA as cargo. DNMT3B also interacts with histone deacetylase 1 (HDAC1), the co-repressor SIN3A and the ATP-dependent chromatin remodeling enzyme hSNF2H. Further more, DNMT3B co-localizes with condensin and KIF4A on condensed chromosomes throughout mitosis. These studies therefore reveal the first direct link between the machineries regulating DNA methylation and mitotic chromosome condensation in mammalian cells.     

An annotated checklist of Culicoides Latreille, 1809 (Insecta: Ceratopogonidae: Diptera) with incorporation of a vector species list from India

Culicoides Latreille, 1809 (Insecta : Diptera : Ceratopogonidae) are small nematocerous biological vectors of a wide range of pathogens of veterinary and medical importance. They are distributed worldwide but prefer warm, damp, and muddy areas. Female midges require blood for egg maturation. Studies on taxonomy, proper identification keys, and distribution patterns of these flies across different geographical regions of India of these flies are limited. This article provides an updated checklist of Culicoides spp. from India collected from various scattered publications, along with their synonyms and details on their subgenera, geographical distribution, and type locality. A compiled list of different Culicoides vectors from India has also been included separately in this article, along with the type of the diseases spread.     

Age‐Related Differences in the Lifestyle Regularity of Seniors Experiencing Bereavement,Care‐Giving,Insomnia, and Advancement Into Old‐Old Age

Compared to younger adults, seniors (≥60 yrs) often adopt a highly regular lifestyle, perhaps as an adaptive response to age‐related changes in their sleep and circadian rhythms. At baseline, diary measures of lifestyle regularity (SRM‐5) were obtained from 104 seniors of three separate groups. Thirty‐three subjects were challenged by spousal bereavement or the need to care for a spouse at home with dementia (Challenged); 33 were suffering from formally diagnosed (DSM‐IV) insomnia (Insomnia); and 38 were healthy, well‐functioning older seniors in the second half of their eighth decade of life or later (Healthy Older). The objective of this study was to determine whether lifestyle regularity increased as a function of age within each of these three senior groups. Overall, age was significantly correlated with SRM‐5 (r=0.41, p<0.001), with the SRM score increasing by 0.67 units/decade. The same was true for the Challenged and Insomnia groups, which also showed a significant correlation between SRM and age (Challenged: r=0.48, p<0.01; Insomnia: r=0.36, p<0.05), though with a slightly faster rate of SRM increase in the Challenged (0.95 units/decade) than Insomnia (0.55 units/decade) group. Perhaps there was no correlation between age and SRM (r=0.07, n.s.) in the Healthy Older group due to the small age range, although this group did have a higher overall SRM score than the other two groups (p<0.01). The study thus confirmed that the previously observed increase in lifestyle regularity over the adult lifespan persists into later life. This may represent an adaptive behavioral response that might be used in future therapeutic approaches.     

Restoration of p53/miR-34a regulatory axis decreases survival advantage and ensures Bax-dependent apoptosis of non-small cell lung carcinoma cells

Tumor-suppressive miR-34a, a direct target of p53, has been shown to target several molecules of cell survival pathways. Here, we show that capsaicin-induced oxidative DNA damage culminates in p53 activation to up-regulate expression of miR-34a in non-small cell lung carcinoma (NSCLC) cells. Functional analyses further indicate that restoration of miR-34a inhibits B cell lymphoma-2 (Bcl-2) protein expression to withdraw the survival advantage of these resistant NSCLC cells. In such a proapoptotic cellular milieu, where drug resistance proteins are also down-regulated, p53-transactivated Bcl-2 associated X protein (Bax) induces apoptosis via the mitochondrial death cascade. Our results suggest that p53/miR-34a regulatory axis might be critical in sensitizing drug-resistant NSCLC cells.     

Age and orientation of the cotyledonary leaf explants determine the efficiency of de novo plant regeneration and Agrobacterium tumefaciens-mediated transformation in Jatropha curcas L.

Effects of age and orientation of the explant on callus induction and de novo shoot regeneration from cotyledonary leaf segments of Jatropha curcas were studied. The callus induction and shoot regeneration capacity of cotyledonary leaf segments were found significantly related to the age of the explants and their orientation in culture medium. The youngest explant, derived from the cotyledonary leaf of germinated seed induced the highest regeneration response as compared to one- and two-week-old explants. A gradient response with age of the explant was observed in percentage of callus induction, shoot regeneration from callus and the number of shoots per regenerating callus. The explants cultured with their abaxial side in medium showed significantly higher regeneration response. The youngest explant was found to be most amenable to Agrobacterium-mediated transformation as compared to older explants. The fact that callus induced from the edges of the explant followed by de novo shoot induction, and strong transient gus expression observed in the edges of the explant are significant for routine Agrobacterium-mediated transformation and generation of stable transgenic plants in J. curcas.     

Fluorescence polarization as a tool to study lectin-sugar interaction

The binding ofRicinus communis agglutinin andAbrus agglutinin to 4-methylumbelliferyl β-D-galactopyranoside was studied by equilibrium dialysis, fluo-rescence quenching and fluorescence polarization. The number of binding sites and the association constant value obtained by fluorescence polarization for bothRicinus communis agglutinin andAbrus agglutinin are in close agreement with those obtained by the other methods. This indicates the potential of ligand-fluorescence polarization measurements in the investigation of lectin-sugar interactions.