Escape of intracellular Shigella from autophagy requires binding to cholesterol through the type III effector,IcsB

Type III secretion systems are present in many pathogenic bacteria and mediate the translocation of bacterial effectors into host cells. Identification of host targets of these effectors is crucial for understanding bacterial virulence. IcsB, a type III secretion effector, helps Shigella to evade the host autophagy defense system by binding to the autophagy protein, Atg5. Here, we show that IcsB is able to interact specifically with cholesterol. The cholesterol binding domain (CBD) of IcsB is located between residues 288 and 351. Specific mutations of single tyrosine residues Y297 or Y340 of IcsB by phenylalanine (F) slightly reduced cholesterol binding, whereas deletion of the entire CBD or double mutation Y297F-Y340F strongly abolished interactions with cholesterol. To determine whether Shigella expressing IcsB variants could evade autophagy as effectively as the wild-type Shigella, we infected MDAMC cells stably expressing the autophagy marker LC3 fused to GFP and bacterial autophagosome formation was quantified using fluorescence microscopy. Mutation Y297F or Y340F slightly impaired IcsB function, whereas complete removal of CBD or mutation Y297F-Y340F significantly impaired autophagy evasion. Furthermore, we report that BopA, the counterpart of IcsB in Burkholderia pseudomallei with similar autophagy-evading properties, contains the CBD domain and is also able to bind cholesterol.     

Fibre bundle element method of determining physiological cross-sectional area from three-dimensional computer muscle models created from digitised fibre bundle data

Physiological cross-sectional area (PCSA) is used to compare force-producing capabilities of muscles. A limitation of PCSA is that it cannot be measured directly from a specimen, as there is usually no area within the muscle traversed by all fibres. Traditionally, a formula requiring averaged architectural parameters has been used. The purpose of this paper is to describe the development of a fibre bundle element (FBE) method to calculate PCSA from digitised fibre bundle data of five architecturally distinct muscles and compare the FBE and PCSA formula. An FBE method was developed that used a serially arranged set of cylinders as the volumetric representation of each fibre bundle, and PCSA was computed as the summation of the cross-sectional area of each FBE. Four of five muscles had significantly different PCSA between FBE and formula methods. The FBE method provides an approach that considers architectural variances while minimising the need for averaged architectural parameters.     

Phenotypic variability of quantitative traits in Indian populations of Drosophila kikkawai

Drosophila kikkawai, which has colonized the Indian subcontinent in the recent past, exhibits geographical variations for five quantitative traits among eight Indian populations (8.29–32.7°N). Body weight, wing length, thorax length, abdominal bristles and ovariole number exhibit significant clinal variation with increase in latitude, while sternopleural bristles do not demonstrate such a trend. For the female sex, the slope values for body weight (2.25) and wing length (2.40) are higher but they are lower for thorax length (0.64) and ovariole number (0.51 per degree latitude). There is significant sexual dimorphism for the slope values only for body weight and thorax length suggesting simultaneous action of latitudinal selection pressure on these traits. However, the two sexes do not differ statistically in the latitudinal slope values for the wing length. A regression analysis of different traits on body weight implies correlated selection response on wing length and wing/thorax ratio while thorax length corresponds to changes in body size and does not differ in the two sexes. Regression analysis, on the basis of temperature-related climatic variables, evidence significantly higher association between all the five size-related traits and coefficient of variation of mean annual temperature (seasonal thermal amplitude; T _cv), T _min and relative humidity. Thus, genetic differentiation for quantitative traits in D. kikkawai are due to selective pressure from variable climatic conditions occurring on the Indian subcontinent.     

Some new hosts to Leptosphaerulina McAlp. from India

Summary The present paper describes a species ofLeptosphaerulina occurring on 10 angiospermic hosts belonging to 7 families of dicotyledons. On the basis of perithecial size, shape, septation and size of ascospores, the fungus occurring on all these hosts was considered to be belonging to a single species which was identified asL. australis McAlp. Further work on the taxonomy and nutritional requirements of the fungus is under investigation.     

Moving to Universal Coverage? Trends in the Burden of Out-Of-Pocket Payments for Health Care across Social Groups in India, 1999–2000 to 2011–12

In the background of ongoing health sector reforms in India, the paper investigates the magnitude and trends in out-of-pocket and catastrophic payments for key population sub-groups. Data from three rounds of nationally representative consumer expenditure surveys (1999–2000, 2004–05 and 2011–12) were pooled to assess changes over time in a range of out-of-pocket -related outcome indicators for the poorest 20% households, scheduled caste and tribe households and Muslims households relative to their better-off/majority religion counterparts. Our results suggest that the poorest 20% of households experienced a decline in the proportion reporting any OOP for inpatient care relative to the top 20% and Muslim households saw an increase in the proportion reporting any inpatient OOP relative to non-Muslim households during 2000-2012. The change in the proportion of Muslim households or SC/ST households reporting any OOP for outpatient care was similar to that for their respective more advantaged counterparts; but the poorest 20% of households experienced a faster increase in the proportion reporting any OOP for outpatient care than their top 20% counterparts. SC/ST, Muslim and the poorest 20% of households experienced as faster increase in the share of outpatient OOP in total household spending relative to their advantaged counterparts. We conclude that the financial burden of out of pocket spending increased faster among the disadvantaged groups relative to their more advantaged counterparts. Although the poorest 20% saw a relative decline in OOP spending on inpatient care as a share of household spending, this is likely the result of foregoing inpatient care, than of accessing benefits from the recent expansion of cashless publicly financed insurance schemes for inpatient care. Our results highlight the need to explore the reasons underlying the lack of effectiveness of existing public health financing programs and public sector health services in reaching less-advantaged castes and religious minorities.     

A novel organic solvent tolerant protease from a newly isolated Geomicrobium sp. EMB2 (MTCC 10310): production optimization by response surface methodology

Thirty-eight haloalkaliphilic bacterial strains were isolated from Sambhar Salt Lake, India and screened for their ability to secrete haloalkaliphilic proteases. Among them, a moderately halophilic, mesophilic and alkaliphilic potent strain Geomicrobium sp. EMB2 produced an extracellular protease, which was remarkably stable in organic solvents, salt, surfactants, detergents and alkaline pH. Statistically based experimental designs were applied to study the interactions and optimization of medium constituents for efficient protease production by Geomicrobium sp. EMB2. An overall 20-fold increase in protease production was achieved in the optimized medium (721 U/ml) as compared with the unoptimized medium (37 U/ml). The high production level coupled with novel properties makes it a prospective industrial enzyme. The Geomicrobium sp. EMB2 isolate is deposited in Microbial Type Culture Collection, Chandigarh, India with accession number MTCC 10310.     

Endogenous auxin level is a critical determinant for in vitro adventitious shoot regeneration in potato (Solanum tuberosum L.)

Endogenous levels of indole-3-acetic acid (IAA) were determined in the internodal explants of Indian tetraploid potato cultivars (cvs) viz., Kufri Sutlej (K.Sutlej) and Kufri Giriraj (K.Giriraj). Seven fold higher level of endogenous IAA was recorded for cv K.Sutlej over cv K.Giriraj. As a result, perhaps there was a callusing response from the cut end of the internodal explants of both the cvs in the MS basal medium. The extent of callusing was relatively higher in cv K.Sutlej when compared to that in K.Giriraj. The callusing response was inhibitory to shoot morphogenesis. Inclusion of an established anti-auxin, 2,3,5-tri-iodobenzoic acid (TIBA) in the regeneration medium facilitated a high frequency adventitious shoot regeneration response with lower cytokinin levels. Murashige and Skoog (MS) medium containing TIBA at 2.5?mg?l^?1 and 0.25?mg?l^?1 zeatin evoked a 100% regeneration response (4.5 shoot buds per explant) in cv K.Sutlej within 20?C25?days. However, in cv K.Giriraj, which had lower levels of endogenous IAA, 80% regeneration response (1.4 shoot buds per explant) was recorded in an extended period of 40?C45?days on a medium containing 0.5?mg?l^?1 TIBA and 0.1?mg?l^?1 zeatin. Although, TIBA and zeatin induced shoot bud formation, it failed to support sustained growth of the regenerated shoots in cv K.Giriraj. Hence, 0.01?mg?l^?1 ??-naphthaleneacetic acid (NAA) with a relatively higher concentration of zeatin (1.0?mg?l^?1) were used for sustained shoot regeneration (3.3 shoot buds per explant) within 25?days. From our results, it is evident that there was a difference in the requirement of exogenous zeatin levels required to induce a regeneration response in two cultivars of potato and this is attributed to the variable levels of endogenous IAA.     

Serum Metabolomics of Slow vs. Rapid Motor Progression Parkinson’s Disease: a Pilot Study

Progression of Parkinson’s disease (PD) is highly variable, indicating that differences between slow and rapid progression forms could provide valuable information for improved early detection and management. Unfortunately, this represents a complex problem due to the heterogeneous nature of humans in regards to demographic characteristics, genetics, diet, environmental exposures and health behaviors. In this pilot study, we employed high resolution mass spectrometry-based metabolic profiling to investigate the metabolic signatures of slow versus rapidly progressing PD present in human serum. Archival serum samples from PD patients obtained within 3 years of disease onset were analyzed via dual chromatography-high resolution mass spectrometry, with data extraction by xMSanalyzer and used to predict rapid or slow motor progression of these patients during follow-up. Statistical analyses, such as false discovery rate analysis and partial least squares discriminant analysis, yielded a list of statistically significant metabolic features and further investigation revealed potential biomarkers. In particular, N8-acetyl spermidine was found to be significantly elevated in the rapid progressors compared to both control subjects and slow progressors. Our exploratory data indicate that a fast motor progression disease phenotype can be distinguished early in disease using high resolution mass spectrometry-based metabolic profiling and that altered polyamine metabolism may be a predictive marker of rapidly progressing PD.