IL10 Variant g.5311A Is Associated with Visceral Leishmaniasis in Indian Population

BackgroundVisceral leishmaniasis (VL) is a multifactorial disease, where the host genetics play a significant role in determining the disease outcome. The immunological role of anti-inflammatory cytokine, Interleukin 10 (IL10), has been well-documented in parasite infections and considered as a key regulatory cytokine for VL. Although VL patients in India display high level of IL10 in blood serum, no genetic study has been conducted to assess the VL susceptibility / resistance. Therefore, the aim of this study is to investigate the role of IL10 variations in Indian VL; and to estimate the distribution of disease associated allele in diverse Indian populations.MethodologyAll the exons and exon-intron boundaries of IL10 were sequenced in 184 VL patients along with 172 ethnically matched controls from VL endemic region of India.

Result and Discussion

Our analysis revealed four variations; rs1518111 (2195 A>G, intron), rs1554286 (2607 C>T, intron), rs3024496 (4976 T>C, 3’ UTR) and rs3024498 (5311 A>G, 3’ UTR). Of these, a variant g.5311A is significantly associated with VL (χ²=18.87; p =0.00001). In silico approaches have shown that a putative micro RNA binding site (miR-4321) is lost in rs3024498 mRNA. Further, analysis of the above four variations in 1138 individuals from 34 ethnic populations, representing different social and linguistic groups who are inhabited in different geographical regions of India, showed variable frequency. Interestingly, we have found, majority of the tribal populations have low frequency of VL (‘A’ of rs3024498); and high frequency of leprosy (‘T’ of rs1554286), and Behcet’s (‘A’ of rs1518111) associated alleles, whereas these were vice versa in castes. Our findings suggest that majority of tribal populations of India carry the protected / less severe allele against VL, while risk / more severe allele for leprosy and Behcet’s disease. This study has potential implications in counseling and management of VL and other infectious diseases.     

DNA photolyase of enterococci: possible explanation for its low sunlight inactivation rate

DNA photolyase is perhaps the most ancient and direct arsenal in curing the UV-induced dimers formed in the microbial genome. Out of two cofactors of the enzyme, catalytic and light harvesting, differences in the latter have provided basis for categorizing photolyases of prokaryotes as folate and deazaflavin types. In the present study, the homology modeling of DNA photolyase of Enterococcus faecalis was undertaken. The predicted models were structurally compared with the crystal structure coordinates of photolyases from Escherichia coli (folate type) and Anacystis nidulans (deazaflavin type). Discrepancies present in the multiple sequence alignment and tertiary structures, particularly at the light harvesting cofactor (methenyltetrahydrofolic acid, MTHF; 8-hydroxy-5-deazaflavin, 8-HDF) binding sites indicated the mechanistic nature of enterococcal photolyase. Concisely, despite the greater holistic homology with folate-type photolyase, enterococcal photolyase was characterized as deazaflavin-type. The presence of 8-HDF binding sites and groove architecture of substrate binding sites were also found supportive in this regard. The inter cofactor distance and/or orientation also implied to the efficient energy transfer in photolyase of Enterococcus in comparison with E. coli. In addition, we observed relatively high protein deformability in the enterococcal genome, which may favors the repair action of photolyase. The findings are expected to provide molecular insights into the difference in sunlight inactivation rate of two important fecal contamination indicators, namely Enterococcus and E. coli.     

Formative effects of morphactin on the shoot apical meristem of flax (linum usitatissimum L.).

The effect of a morphactin -- CF1 -- (2-chloro-9-hydroxyfluorene-9-carbocylic acid-methyl ester) on the morphogenesis of shoot apical meristem was studied on L. usitatissimum L. at three levels of supply. CF1 at 10 and 100 parts/10(6) induced repeated gamophylly resembling a concentric cupulate structure. GA3 superimposed at two levels viz. 10 and 100 parts/10(6) did not reverse this effect. The effect of CF1 is dose-dependent and reversal to normal behaviour occurs when the effect of CF1 wears off.     

Heteromers of Glutamate Decarboxylase Isoforms Occur in Rat Cerebellum

Abstract: The subunit structure of brain glutamate decarboxylase in cerebellum was investigated by using gel electrophoresis and antisera that specifically recognize the individual isoforms of brain glutamate decarboxylase (termed GAD₆₅ and GAD₆₇). The antisera were prepared against peptides that corresponded to amino acid sequences specific to each isoform. Each antiserum reacted specifically with the appropriate peptide in an ELISA and with the appropriate form of GAD on immunoblots. Nondenaturing gradient gel electrophoresis indicated that GAD is principally multimeric with monomeric forms comprising <3% of the total. Immunoprecipitation and immunoaffinity chromatography experiments were performed with antisera W624 and W883, which were prepared against peptides specific to GAD₆₅ and GAD₆₇, respectively. Immunoprecipitates prepared from cerebellar supernatants with W624 contained both GAD₆₅ and GAD₆₇, whereas some GAD₆₇ was left in the supernatant. In a similar manner, immunoprecipitates prepared with W883 contained both GAD₆₅ and GAD₆₇, whereas some GAD₆₅ remained in the supernatant. In addition, immunoaffinity columns prepared with either W624 or W883 retained both GAD₆₅ and GAD₆₇ even after extensive washing. These results are consistent with the presence of heteromultimers of GAD₆₅ and GAD₆₇ in cerebellum in addition to homomers of each form.     

Corals shed bacteria as a potential mechanism of resilience to organic matter enrichment

Understanding the mechanisms of resilience of coral reefs to anthropogenic stressors is a critical step toward mitigating their current global decline. Coral–bacteria associations are fundamental to reef health and disease, but direct observations of these interactions remain largely unexplored. Here, we use novel technology, high-speed laser scanning confocal microscopy on live coral (Pocillopora damicornis), to test the hypothesis that corals exert control over the abundance of their associated bacterial communities by releasing (‘shedding'') bacteria from their surface, and that this mechanism can counteract bacterial growth stimulated by organic inputs. We also test the hypothesis that the coral pathogen Vibrio coralliilyticus can evade such a defense mechanism. This first report of direct observation with high-speed confocal microscopy of living coral and its associated bacterial community revealed a layer (3.3–146.8 μm thick) on the coral surface where bacteria were concentrated. The results of two independent experiments showed that the bacterial abundance in this layer was not sensitive to enrichment (5 mg l⁻¹ peptone), and that coral fragments exposed to enrichment released significantly more bacteria from their surfaces than control corals (P<0.01; 35.9±1.4 × 10⁵ cells cm⁻² coral versus 1.3±0.5 × 10⁵ cells cm⁻² coral). Our results provide direct support to the hypothesis that shedding bacteria may be an important mechanism by which coral-associated bacterial abundances are regulated under organic matter stress. Additionally, the novel ability to watch this ecological behavior in real-time at the microscale opens an unexplored avenue for mechanistic studies of coral–microbe interactions.