Variations in Abundance,Genome Size,Morphology, and Functional Role of the Virioplankton in Lakes Annecy and Bourget over a 1-Year Period

We sampled the surface waters (2–50 m) of two deep peri-alpine lakes over a 1-year period in order to examine (1) the abundance, vertical distribution, genome size, and morphology structures of the virioplankton; (2) the virus-mediated bacterial mortality; and (3) the specific genome size range of double-stranded DNA (dsDNA) phytoplankton viruses. Virus-like particle (VLP) concentrations varied between 4.16?×?10⁷ (January) and 2.08?×?10⁸ part mL^?1 (May) in Lake Bourget and between 2.7?×?10⁷ (June) and 8.39?×?10⁷ part mL^?1 (November) in Lake Annecy. Our flow cytometry analysis revealed at least three viral groups (referred to as virus-like particles 1, 2, and 3) that exhibited distinctive dynamics suggestive of different host types. Phage-induced bacterial mortality varied between 6.1 % (June) and 33.2 % (October) in Lake Bourget and between 7.4 % (June) and 52.6 % (November) in Lake Annecy, suggesting that viral lysis may be a key cause of mortality of the bacterioplankton. Virioplankton genome size ranged from 27 to 486 kb in Lake Bourget, while it reached 620 kb in Lake Annecy for which larger genome sizes were recorded. Our analysis of pulsed field gel electrophoresis bands using different PCR primers targeting both cyanophages and algal viruses showed that (1) dsDNA viruses infecting phytoplankton may range from 65 to 486 kb, and (2) both cyanophage and algal “diversity” were higher in Lake Annecy. Lakes Annecy and Bourget also differed regarding the proportions of both viral families (with the dominance of myoviruses vs. podoviruses) and infected bacterial morphotypes (short rods vs. elongated rods), in each of these lakes, respectively. Overall, our results reveal that (1) viruses displayed distinct temporal and vertical distribution, dynamics, community structure in terms of genome size and morphology, and viral activity in the two lakes; (2) the Myoviridae seemed to be the main cause of bacterial mortality in both lakes and this group seemed to be related to VLP2; and (3) phytoplankton viruses may have a broader range of genome size than previously thought. This study adds to growing evidence that viruses are diverse and play a significant role in freshwater microbial dynamics and more globally lake functioning. It highlights the importance of further considering this biological compartment for a better understanding of plankton ecology in peri-alpine lakes.     

Production of xylanase by immobilized Trichoderma reesei SAF3 in Ca-alginate beads

In the present study, the optimum conditions for the production of xylanase by immobilized spores of Trichoderma reesei SAF3 in calcium alginate beads were determined. The operational stability of the beads during xylanase production under semi-continuous fermentation was also studied. The influence of alginate concentration (1, 2, 3, and 4%) and initial cell loading (100, 200, 300, 400, and 500 beads per flask) on xylanase production was considered. The production of xylanase was found to increase significantly with increasing concentration of alginate and reached a maximum yield of 3.12 ± 0.18 U ml⁻¹ at 2% (w/v). The immobilized cells produced xylanase consistently up to 10 cycles and reached a maximum level at the forth cycle (3.36 ± 0.2 U ml⁻¹).     

Recent trends in fungal laccase for various industrial applications: An eco-friendly approach - A review

The aim of this review is to determine the trends of state-of-art of laccase sources, properties, structure and recent application of fungal laccase in various fields. Laccases are biotechnologically important multi copper proteins that have broad substrate specificity towards aromatic and non-aromatic compounds. Fungi are the major laccase producers especially ascomycetes, deuteromycetes and basidiomycetes, and laccases have an average molecular weight between 50 and 130 kDa. Fungal laccases are used in biotechnological applications for preparation of anticancerous and anti-oxidant hormonal drugs, stabilization of food products, and laccase application is also extended to preparation of biosensors, DNA labeling, immunochemical assay, bioorganic compound synthesis etc. The environmental application of laccase is for biodegradation of dyes, phenols and pesticides, and the mechanism of degradation has been briefly explained. Analysis of the biodegraded dye sample by FT-IR and Mass (ESI)-spectrum has been discussed in a detailed manner. Modeling kinetics has been discussed with respect to degradation of wastes in order to understand the factors involved in the degradation process.     

Endoglucanase from the mixed culture of Trichoderma reesei and Aspergillus wentii

The level of α-mannanase in mixed fungal culture of Trichoderma reesei, D1-6, and Aspergillus wentii, Pt 2804, affects the extracellular activities of cellulase. The endoglucanase component of the cellulase system is a glycoprotein having mannose and other sugars and sugaramines in its glycan moiety. Its activity is inhibited by α-mannanase. The inactivation of endoglucanase by α-mannanase can be prevented by galactose.     

IL-4 Haplotype -590T, -34T and Intron-3 VNTR R2 Is Associated with Reduced Malaria Risk among Ancestral Indian Tribal Populations

Background

Interleukin 4 (IL-4) is an anti-inflammatory cytokine, which regulates balance between T_H1 and T_H2 immune response, immunoglobulin class switching and humoral immunity. Polymorphisms in this gene have been reported to affect the risk of infectious and autoimmune diseases.

Methods

We have analyzed three regulatory IL-4 polymorphisms; -590C>T, -34C>T and 70 bp intron-3 VNTR, in 4216 individuals; including: (1) 430 ethnically matched case-control groups (173 severe malaria, 101 mild malaria and 156 asymptomatic); (2) 3452 individuals from 76 linguistically and geographically distinct endogamous populations of India, and (3) 334 individuals with different ancestry from outside India (84 Brazilian, 104 Syrian, and 146 Vietnamese).

Results

The -590T, -34T and intron-3 VNTR R2 alleles were found to be associated with reduced malaria risk (P<0.001 for -590C>T and -34C>T, and P = 0.003 for VNTR). These three alleles were in strong LD (r²>0.75) and the TTR2 (-590T, -34T and intron-3 VNTR R2) haplotype appeared to be a susceptibility factor for malaria (P = 0.009, OR = 0.552, 95% CI = 0.356 –0.854). Allele and genotype frequencies differ significantly between caste, nomadic, tribe and ancestral tribal populations (ATP). The distribution of protective haplotype TTR2 was found to be significant (χ² ₃ = 182.95, p-value <0.001), which is highest in ATP (40.5%); intermediate in tribes (33%); and lowest in caste (17.8%) and nomadic (21.6%).

Conclusions

Our study suggests that the IL-4 polymorphisms regulate host susceptibility to malaria and disease progression. TTR2 haplotype, which gives protection against malaria, is high among ATPs. Since they inhabited in isolation and mainly practice hunter-gatherer lifestyles and exposed to various parasites, IL-4 TTR2 haplotype might be under positive selection.     

Implementation of a k/k(0) method to identify long-range structure in transition states during conformational folding/unfolding of proteins

A previously introduced kinetic-rate constant (k/k(0)) method, where k and k(0) are the folding (unfolding) rate constants in the mutant and the wild-type forms, respectively, of a protein, has been applied to obtain qualitative information about structure in the transition state ensemble (TSE) of bovine pancreatic ribonuclease A (RNase A), which contains four native disulfide bonds. The method compares the folding (unfolding) kinetics of RNase A, with and without a covalent crosslink and tests whether the crosslinked residues are associated in the folding (unfolding) transition state (TS) of the noncrosslinked version. To confirm that the fifth disulfide bond has not introduced a significant structural perturbation, we solved the crystal structure of the V43C-R85C mutant to 1.6 A resolution. Our findings suggest that residues Val43 and Arg85 are not associated, and that residues Ala4 and Val118 may form nonnative contacts, in the folding (unfolding) TSE of RNase A.