Production of xylanases byChaetomium cellulolyticum during growth on lignocelluloses

Summary Chaetomium cellulolyticum was able to produce xylanases on all the three lignocelluloses: wheat straw, corn stover and aspen wood. Wheat straw was the best. Solid state fermentation of lignocelluloses gave higher yields of xylanases than liquid state fermentation, but it took longer time of incubation.     

Effect of magnesium chloride (2:1 electrolyte) on the aqueous solution behavior of some saccharides over the temperature range of 288.15-318.15 K: a volumetric approach

Infinite-dilution standard partial molar volumes, , for various mono-, di-, and trisaccharides, and their derivatives (methyl glycosides) at molalities ranging from 0.04 to 0.12 mol kg⁻¹ in aqueous solutions of magnesium chloride of 0.5, 1.0, 2.0, and 3.0 mol kg⁻¹, have been evaluated over a range of temperatures from 288.15 to 318.15 K by density measurements employing a vibrating-tube densimeter. These data have been utilized to determine the corresponding standard partial molar volumes of transfer, , of saccharides and methyl glycosides from water to aqueous magnesium chloride solutions. The values have been found to be positive, and their magnitudes increase with an increasing concentration of magnesium chloride in all cases. Partial molar expansion coefficients, and second derivatives thereof, have been estimated. The magnitude of values increases with an increase in temperature, indicating that hydration effects in solutions are strongly sensitive to temperature. Pair and higher order volumetric interaction coefficients (V_AB, V_ABB) have also been obtained from values by using the McMillan-Mayer theory. The various parameters have been discussed in terms of the solute (saccharide or methyl glycoside)-co-solute (magnesium chloride) interactions and are thus used to understand the mixing effects due to these interactions. These results have been compared with those earlier reported in the presence of electrolytes. An attempt is made to interpret the volumetric properties data in terms of the stereochemistry of the solutes.     

Starvation Resistance in a Stenothermal Species from the Indian Subcontinent: Mechanistic Basis of Clinal Variation

Parallel clines for starvation resistance and lipid content are well documented among drosophilids on the Indian subcontinent. However, the mechanistic basis of these clines has not been investigated so far. Here, we investigate the utilization of lipids during starvation as a function of duration of stress in D. ananassae. We found higher lipid content responsible for high starvation resistance at lower latitudes. Lipids were utilized during starvation only; not during any other climatic stresses like desiccation or thermal stresses. We also found a cline for consumption of total body lipids; as more content (out of total amount of lipids) was utilized by flies at lower latitudes and lesser at higher latitudes. But, there was no latitudinal cline for threshold lipid amount in the case of females while for males there was a positive cline. Lastly, parallel clines have evolved under contrasting climatic conditions i.e. drier and colder northern localities have flies with lower lipid and reduced starvation resistance while hot and humid localities favor flies with higher lipid levels and greater starvation tolerance. Thus, the evolution of clines associated with starvation and lipid content might have resulted due to specific ecological conditions i.e. humidity gradient on the Indian subcontinent.     

Reduced Infectivity of Adenovirus Type 5 Particles and Degradation of Entering Viral Genomes Associated with Incomplete Processing of the Preterminal Protein

To investigate further the contribution of the adenovirus type 5 (Ad5) E1B 55-kDa protein to genome replication, viral DNA accumulation was examined in primary human fibroblasts and epithelial cells infected with Ad5 or the E1B 55-kDa-null mutant Hr6. Unexpectedly, all cell types were observed to contain a significantly higher concentration of entering Hr6 than of Ad5 DNA, as did an infectious unit of Hr6. However, the great majority of the Hr6 genomes were degraded soon after entry. As this unusual phenotype cannot be ascribed to the Hr6 E1B frameshift mutation (J. S. Chahal and S. J. Flint, J. Virol. 86:3064–3072, 2012), the sequences of the Ad5 and Hr6 genomes were compared by using high-throughput sequencing. Seven previously unrecognized mutations were identified in the Hr6 genome, two of which result in substitutions in virion proteins, G315V in the preterminal protein (preTP) and A406V in fiber protein IV. Previous observations and the visualization by immunofluorescence of greater numbers of viral genomes entering the cytosol of Hr6-infected cells than of Ad5-infected cells indicated that the fiber mutation could not be responsible for the low-infectivity phenotype of Hr6. However, comparison of the forms of terminal protein present in purified virus particles indicated that the production of mature terminal protein from a processing intermediate is impaired in Hr6 particles. We therefore propose that complete processing of preTP within virus particles is necessary for the ability of viral genomes to become localized at appropriate sites and persist in infected cells.     

Sleep disturbance and cardiovascular risk in adolescents

Background:

Evidence suggests that inadequate or disturbed sleep is associated with increased cardiovascular risk in adults. There are limited data on sleep quality and associated cardiovascular risk in children.

Methods:

We obtained data on adolescents from the 2009/10 cycle of the Healthy Heart Schools’ Program, a population-based cross-sectional study in the Niagara region of Ontario. Participants underwent measurements of cardiometabolic risk factors, including body mass index (BMI), lipid profile and blood pressure, and they completed questionnaires measuring sleeping habits and nutritional status. We assessed sleep disturbance using the sleep disturbance score derived from the Pittsburgh Sleep Quality Index. We explored associations between sleeping habits and cardiovascular risk factors.

Results:

Among 4104 adolescents (51% male), the mean hours of sleep per night (± standard deviation) were 7.9 ± 1.1 on weeknights and 9.4 ± 1.6 on weekends. In total, 19% of participants reported their sleep quality as fairly bad or very bad on weeknights and 10% reported it as fairly bad or very bad on weekends. In the multivariable regression models, a higher sleep disturbance score was associated with increased odds of being at high cardiovascular risk (highest v. lowest tertile odds ratio [OR] 1.43 [95% confidence interval (CI) 1.16–1.77], p < 0.001), increased odds of hypertension (highest v. lowest tertile OR 1.44 [95% CI 1.02–2.05], p = 0.05) and increased odds of elevated non-high density lipoprotein cholesterol (highest v. lowest tertile OR 1.28 [95% CI 1.00–1.64], p = 0.05). The mean duration of sleep was not associated with these outcomes.

Interpretation:

In healthy adolescents, sleep disturbance is associated with cardiovascular risk factor abnormalities. Intervention strategies to optimize sleep hygiene early in life may be important for the prevention of cardiovascular disease.There is emerging evidence in experimental and epidemiologic studies that sleep parameters, specifically sleep duration and quality, are associated with cardiovascular outcomes, including hypertension,¹ as well as diabetes,² hypercholesterolemia³ and obesity.⁴ A recent meta-analysis involving 400 000 adults concluded that short sleep duration was associated with a greater risk of developing or dying from coronary heart disease.⁵ On average, adolescents sleep less than 8 hours per night,⁶ less than the recommended 9 hours,⁷ and about 20% of adolescents have significant sleep problems.⁶ Despite this knowledge, there is a paucity of epidemiologic research on the cardiovascular consequences of short sleep duration and impaired sleep quality in adolescents.In this study, we investigated the association between sleep disturbance and duration and measures of cardiovascular disease risk, including cholesterol, hypertension, body mass index (BMI) and dietary factors in adolescents.     

Bacillithiol has a role in Fe–S cluster biogenesis in Staphylococcus aureus

Staphylococcus aureus does not produce the low‐molecular‐weight (LMW) thiol glutathione, but it does produce the LMW thiol bacillithiol (BSH). To better understand the roles that BSH plays in staphylococcal metabolism, we constructed and examined strains lacking BSH. Phenotypic analysis found that the BSH‐deficient strains cultured either aerobically or anaerobically had growth defects that were alleviated by the addition of exogenous iron (Fe) or the amino acids leucine and isoleucine. The activities of the iron–sulfur (Fe–S) cluster‐dependent enzymes LeuCD and IlvD, which are required for the biosynthesis of leucine and isoleucine, were decreased in strains lacking BSH. The BSH‐deficient cells also had decreased aconitase and glutamate synthase activities, suggesting a general defect in Fe–S cluster biogenesis. The phenotypes of the BSH‐deficient strains were exacerbated in strains lacking the Fe–S cluster carrier Nfu and partially suppressed by multicopy expression of either sufA or nfu, suggesting functional overlap between BSH and Fe–S carrier proteins. Biochemical analysis found that SufA bound and transferred Fe–S clusters to apo‐aconitase, verifying that it serves as an Fe–S cluster carrier. The results presented are consistent with the hypothesis that BSH has roles in Fe homeostasis and the carriage of Fe–S clusters to apo‐proteins in S. aureus.     

Opposite Latitudinal Clines for First Mating and Second Mating (Remating) in Males of Drosophila melanogaster

Although female remating has been studied extensively in insects, few studies have been carried out for male remating (second mating). In this study, we analyzed Drosophila melanogaster males for their remating potential, using iso‐female line culture initiated with wild flies collected from eight Indian geographic localities. We examined the association of latitude and percent melanization with first and second male mating (including mating‐related traits). Our results indicated that second male mating has a negative latitudinal cline opposite to that of first mating. Body melanization is negatively correlated with second mating by male and positively with first mating (measured in terms of percent mated pairs). Mating latency during first (ML1) and second (ML2) male mating has a negative latitudinal cline, but slope values differ significantly as ML2 is great at higher latitudes as compared to ML1. The difference between ML1 and ML2 is non‐significant at lower latitudes. However, copulation period of second mating (CP2) has a negative latitudinal cline, whereas copulation period of first mating (CP1) has positive latitudinal cline. Next, the latency and copulation period differ significantly between first and second male mating treatments in within‐population analyses as well as in melanic strains. Furthermore, male remating ability (number of maximum successful remating attempts continuously by a male in 12 h) also follows negative latitudinal cline. The lower latitudinal lighter males have more remating ability as compared to darker males from higher latitudes.