Molecular characterization of novel Bradyrhizobium strains nodulating Eriosema chinense and Flemingia vestita,important unexplored native legumes of the sub-Himalayan region (Meghalaya) of India

Root nodule bacterial strains were isolated from the little-studied legumes Eriosema chinense and Flemingia vestita (both in tribe Phaseoleae, Papilionoideae) growing in acidic soil of the sub-Himalayan region of the Indian state of Meghalaya (ME), and were identified as novel strains of Bradyrhizobium on the basis of their 16S rRNA sequences. Seven isolates selected on the basis of phenotypic characters and assessment of ARDRA and RAPD patterns were subjected to multilocus sequence analysis (MLSA) using four protein-coding housekeeping genes (glnII, recA, dnaK and gyrB). On the basis of 16S rRNA phylogeny as well as a concatenated MLSA five strains clustered in a single separate clade and two strains formed novel lineages within the genus Bradyrhizobium. The phylogenies of the symbiotic genes (nodA and nifH) were in agreement with the core gene phylogenies. It appears that genetically diverse Bradyrhizobium strains are the principal microsymbionts of these two important native legumes. The novel genotypes of Bradyrhizobium strains isolated in the present study efficiently nodulate the Phaseoloid crop species Glycine max, Vigna radiata and Vigna umbellata. These strains are genetically different from strains of Bradyrhizobium isolated earlier from a different agro-climatic region of India suggesting that the acidic nature of the soil, high precipitation and other local environmental conditions are responsible for the evolution of these newly-described Bradyrhizobium strains. In global terms, the sub-Himalayan region of India is geographically and climatically distinct and the Bradyrhizobium strains nodulating its legumes appear to be novel and potentially unique to the region.     

Insulin receptor substrate protein 53kDa (IRSp53) is a negative regulator of myogenic differentiation

Fusion of mononucleated myoblasts to generate multinucleated myotubes is a critical step in skeletal muscle development. Filopodia, the actin cytoskeleton based membrane protrusions, have been observed early during myoblast fusion, indicating that they could play a direct role in myogenic differentiation. The control of filopodia formation in myoblasts remains poorly understood. Here we show that the expression of IRSp53 (Insulin Receptor Substrate protein 53kDa), a known regulator of filopodia formation, is down-regulated during differentiation of both mouse primary myoblasts and a mouse myoblast cell line C2C12. Over-expression of IRSp53 in C2C12 cells led to induction of filopodia and decrease in cell adhesion, concomitantly with inhibition of myogenic differentiation. In contrast, knocking down the IRSp53 expression in C2C12 cells led to a small but significant increase in myotube development. The decreased cell adhesion of C2C12 cells over-expressing IRSp53 is correlated with a reduction in the number of vinculin patches in these cells. Mutations in the conserved IMD domain (IRSp53 and MIM (missing in metastasis) homology domain) or SH3 domain of IRSp53 abolished the ability of this protein to inhibit myogenic differentiation and reduce cell adhesion. Over-expression of the IMD domain alone was sufficient to decrease the cell-extracellular matrix adhesion and to inhibit myogenesis in a manner dependent on its function in membrane shaping. Based on our data, we propose that IRSp53 is a negative regulator of myogenic differentiation which correlates with the observed down regulation of IRSp53 expression during myoblast differentiation to myotubes.     

Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India

Introduction

Studies employing serological, DTH or conventional PCR techniques suggest a vast proportion of Leishmania infected individuals living in regions endemic for Visceral Leishmaniasis (VL) remain asymptomatic. This study was designed to assess whether quantitative PCR (qPCR) can be used for detection of asymptomatic or early Leishmania donovani infection and as a predictor of progression to symptomatic disease.

Methods

The study included 1469 healthy individuals living in endemic region (EHC) including both serology-positive and -negative subjects. TaqMan based qPCR assay was done on peripheral blood of each subject using kDNA specific primers and probes.

Results

A large proportion of EHC 511/1469 (34.78%) showed qPCR positivity and 56 (3.81% of 1469 subjects) had more than 1 calculated parasite genome/ml of blood. However, the number of individuals with parasite load above 5 genomes/ml was only 20 (1.36% of 1469). There was poor agreement between serological testing and qPCR (k = 0.1303), and 42.89% and 31.83% EHC were qPCR positive in seropositive and seronegative groups, respectively. Ten subjects had developed to symptomatic VL after 12 month of their follow up examination, of which eight were initially positive according to qPCR and among these, five had high parasite load.

Discussion

Thus, qPCR can help us to detect significant early parasitaemia, thereby assisting us in recognition of potential progressors to clinical disease. This test could facilitate early intervention, decreased morbidity and mortality, and possibly interruption of disease transmission.     

Ultrastructural immunogold localization of nitric oxide synthase isoforms in rat and human eosinophils

The involvement of nitric oxide (NO) as both pro and anti-inflammatory agent in allergic, airway inflammatory, and asthmatic diseases and the active participation of eosinophils in such ailments have been previously suggested. NO modulates eosinophil number, migration and their survival. The microenvironment of NO synthase (NOS) in subcellular organelles determines its rate and efficiency of catalysis, which in turn influences NO generation at distinct intracellular locales. The present study was undertaken to assess the intracellular distribution of NOS isoforms by transmission electron microscopy followed by morphometric analysis in human and rat eosinophils. Rat eosinophils were explored in parallel, and since they are widely used as model systems to mimic human diseases, a comparative study on NOS localization patterns might provide useful information in deciphering NO role in diverse aspects of eosinophil-related inflammatory ailments. The results demonstrated predominance of neuronal NOS (nNOS) in the eosinophilic granules and even distribution of inducible NOS (iNOS) and nNOS in the cytoplasm and nucleus of human eosinophils. In rat eosinophils, however, iNOS was mainly localized in the eosinophilic granules and nucleus, while nNOS was distributed evenly in cytoplasm and nucleus. Distribution of endothelial NOS (eNOS) in eosinophils was scanty. Differences in NOS isoforms and their localization in human and rat cells might have implications in differential mode of catalysis and functional contribution to eosinophil physiology and pathology, warranting detailed investigations. The present study highlights species-specific differences in the relative abundance and distribution pattern of NOS isoforms in rat and human eosinophils, which should be considered cautiously in interpreting the rat data to humans.     

Fungal Contamination of Raw Materials of Some Herbal Drugs and Recommendation of <Emphasis Type="Italic">Cinnamomum camphora</Emphasis> Oil as Herbal Fungitoxicant

The paper explores fungal infection and aflatoxin B(1) contamination of six medicinal plant samples viz. Adhatoda vasica Nees, Asparagus racemosus Linn., Evolvulus alsinoides Linn., Glycyrrhiza glabra Linn., Plumbago zeylanica Linn. and Terminalia chebula Retz. A total of 858 fungal isolates were detected from the raw materials. Maximum number of fungal isolates was detected from A. racemosus (228). The genus Aspergillus was found to be the most dominant genus causing infection to most of the raw materials. Among the 32 isolates of A. flavus tested, 13 isolates were found to be toxigenic elaborating aflatoxin B(1). The highest elaboration of aflatoxin B(1) was 394.95 ppb by the isolates of A. flavus from G. glabra. The essential oil of Cinnamomum camphora (L.) Presl showed efficacy in arresting aflatoxin B(1) by the toxigenic strain. The growth of a toxigenic strain of A. flavus decreased progressively with increasing concentration of essential oil from leaves of C. camphora. The oil completely inhibited aflatoxin B(1) production even at 750 ppm. Hence, the oil of C. camphora is recommended as herbal fungitoxicant against the fungal contamination of the raw materials.     

Addressing power asymmetries in global health: Imperatives in the wake of the COVID-19 pandemic

Seye Abimbola and co-authors argue for a transformation in global health research and practice in the post-COVID-19 world.

Summary points

• The Coronavirus Disease 2019 (COVID-19) pandemic, the Black Lives Matter and Women in Global Health movements, and ongoing calls to decolonise global health have all created space for uncomfortable but important conversations that reveal serious asymmetries of power and privilege that permeate all aspects of global health.
• In this article, we, a diverse, gender-balanced group of public (global) health researchers and practitioners (most currently living in the so-called global South), outline what we see as imperatives for change in a post-pandemic world.
• At the individual level (including and especially ourselves), we emphasise the need to emancipate and decolonise our own minds (from the colonial conditionings of our education), straddle and use our privilege responsibly (to empower others and avoid elite capture), and build “Southern” networks (to affirm our ownership of global health).
• At the organisational level, we call for global health organisations to practice real diversity and inclusion (in ways that go beyond the cosmetic), to localise their funding decisions (with people on the ground in the driving seat), and to progressively self-decentralise (and so, divest themselves of financial, epistemic, and political power).
• And at both the individual and organisational level, we emphasise the need to hold ourselves, our governments, and global health organisations accountable to these goals, and especially for governance structures and processes that reflect a commitment to real change.
• By putting a spotlight on coloniality and existing inequalities, the COVID-19 pandemic inspires calls for a more equitable world and for a decolonised and decentralised approach to global health research and practice, one that moves beyond tokenistic box ticking about diversity and inclusion into real and accountable commitments to transformative change.

     

GA3-Modulated multiple forms of monophenolase in wheat seed

Multiple forms of monophenolase in wheat half-seeds were separated by molecular sieving on Sephadex G-200. A single molecular form of monophenolase was observed in control, while two multiple forms were present in GA₃-treated wheat half-seeds. A high MW (200 000 or above) multiple form (activity peak I) which eluted soon after the void volume was exclusively present in GA₃-treated half-seeds. The second activity peak (peak II) was a low MW (45 000) multiple form and its elution profile coincided in control and GA₃-treated wheat half-seeds. Both the multiple forms of monophenolase in GA₃-treated wheat half-seeds showed a pH optimum at 9.0, while the optimum enzyme activity of the control molecular form (peak II) was at pH 7.0. This indicated that the treatment of wheat half-seeds with GA₃ brought about a structural modification in monophenolase. The in vitro addition of trypsin enhanced the control of the molecular form of monophenolase but this treatment failed to alter the activity of multiple forms in GA₃-treated half-seeds. This differential response of monophenolase towards trypsin could be ascribed to a conformational change of the enzyme in hormone-treated half-seeds. Brief exposure of the enzyme preparation to urea (6 M) brought about an irreversible activation of monophenolase both in control and GA₃-treated wheat half-seeds.