Coal fly ash utilization in agriculture: its potential benefits and risks

Over the past few decades there has been avid interest in developing the strategies for the utilization of Fly ash (FA). Major foci have been on its agricultural application. It is often economical to use FA as a soil amendment. The potential of FA as a resource material in agriculture is due to its specific physical properties like’s texture, water holding capacity, bulk density, pH etc., and contains almost all the essential plant nutrients. It can be used as in soil that cannot substitute the chemical fertilizers or organic manure it can be used in combination with these to get additional benefits in terms of improvement in soil physical characteristics, increased yields etc. The amount and method of FA application in soil would vary with the type of soil, the crop, grown, the prevailing agro climatic condition and also with the FA characteristics. Although, as an input material FA has many benefits for agriculture applications like, improvement of nutrient deficiency, effectively control various pests infesting etc., in contrast FA also contains number of toxic heavy metals and also have natural radioactivity materials in it. Therefore, proper attention should be given on some important areas related to FA utilization such as long term studies of impact of FA on soil health, heavy metal uptake, plant physiology and growth, crop quality, and continuous monitoring on the soil characteristics. While using FA in agriculture problem of heavy metal toxicity and leaching due to excess dose should also be kept in mind.     

A model of a transmembrane drug-efflux pump from Gram-negative bacteria

In Gram-negative bacteria, drug resistance is due in part to the activity of transmembrane efflux-pumps, which are composed of three types of proteins. A representative pump from Escherichia coli is an assembly of the trimeric outer-membrane protein TolC, which is an allosteric channel, the trimeric inner-membrane proton-antiporter AcrB, and the periplasmic protein, AcrA. The pump displaces drugs vectorially from the bacterium using proton electrochemical force. Crystal structures are available for TolC and AcrB from E. coli, and for the AcrA homologue MexA from Pseudomonas aeruginosa. Based on homology modelling and molecular docking, we show how AcrA, AcrB and TolC might assemble to form a tripartite pump, and how allostery may occur during transport.     

Oscillatory metabolism of Saccharomyces cerevisiae: an overview of mechanisms and models

The budding yeast Saccharomyces cerevisiae displays steady oscillations in continuous cultures under certain conditions. Oscillatory responses are important both metabolically and in process applications. Although much information has become available, a definitive theory to explain and model these oscillations is yet to be formulated. Models of oscillatory cultivation have focussed primarily either on intracellular reactions or on transport processes coupled to substantially lumped intracellular kinetics. This review discusses the development of the models and the directions they provide for a comprehensive model of oscillatory metabolism.     

GABA Requires Nitric Oxide for Alleviating Arsenate Stress in Tomato and Brinjal Seedlings

In recent years, gamma-aminobutyric acid (GABA) and nitric oxide (NO) have drawn much attention in reducing/alleviating metal toxicity in plants. Arsenic is a potentially toxic metal that imposes severe toxic effects on crop plants. Therefore, the present study was an attempt to explore the role of GABA and NO in the amelioration of arsenate As(V) toxicity in tomato and brinjal seedlings. Arsenate toxicity reduced fresh mass about by 17% in tomato and 25% in brinjal seedlings, increased the level of reactive oxygen species, antioxidant enzymes (except glutathione-S-transferase), and altered photosynthesis. However, exogenously applied GABA and sodium nitroprusside (SNP, a NO donor) improved the growth of both vegetables and reduced As(V) toxicity. Interestingly, As(V) toxicity was further increased on applying biosynthetic inhibitor of NO even in the presence of GABA, and under similar conditions addition of NO donor rescued the negative effect of biosynthetic inhibitor (L-NAME) of NO. This indicates that NO is crucial in GABA-mediated alleviation of As(V) toxicity in tomato and brinjal seedlings. Besides this, results revealed that c-PTIO (a NO scavenger) addition reversed the alleviatory effect of SNP also suggesting that NO is important in curtailing As(V) toxicity. Overall, the results indicated that NO is necessary for mitigation of As(V) stress by GABA in two studied vegetable crops but NO itself does not require GABA for the same.

     

Microbiota instruct IL-17A-producing innate lymphoid cells to promote skin inflammation in cutaneous leishmaniasis

Innate lymphoid cells (ILCs) comprise a heterogeneous population of immune cells that maintain barrier function and can initiate a protective or pathological immune response upon infection. Here we show the involvement of IL-17A-producing ILCs in microbiota-driven immunopathology in cutaneous leishmaniasis. IL-17A-producing ILCs were RORγt⁺ and were enriched in Leishmania major infected skin, and topical colonization with Staphylococcus epidermidis before L. major infection exacerbated the skin inflammatory responses and IL-17A-producing RORγt⁺ ILC accumulation without impacting type 1 immune responses. IL-17A responses in ILCs were directed by Batf3 dependent CD103⁺ dendritic cells and IL-23. Moreover, experiments using Rag1^-/- mice established that IL-17A⁺ ILCs were sufficient in driving the inflammatory responses as depletion of ILCs or neutralization of IL-17A diminished the microbiota mediated immunopathology. Taken together, this study indicates that the skin microbiota promotes RORγt⁺ IL-17A-producing ILCs, which augment the skin inflammation in cutaneous leishmaniasis.     

Statistical analysis of intermolecular interactions in trypsin-inhibitor complexes

Communicated by Ramaswamy H. Sarma     

Genomic relations among two non-mangrove and nine mangrove species of Indian Rhizophoraceae

Random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers were used to study the genomic relationship among 11 members of Indian Rhizophoraceae represented by nine true mangroves and two non-mangrove species. The AFLP and RAPD bands were scored and analyzed for genetic similarities and cluster analysis was done which separated the 11 species studied into two main groups, the true mangroves and the non-mangroves. The polymorphism observed for these markers showed a high degree of genetic diversity among the constituent taxa of the family. The phylogenetic relationship inferred from molecular marker systems supported the traditional taxonomic classification of the family Rhizophoraceae based on morphological characters at the levels of tribe, phylogeny and delimitation of genera and species, except the intra-generic classification of the genus Bruguiera and the placement of Rhizophora in the family Rhizophoraceae.     

Kinetic comparison of procaspase-3 and caspase-3

Caspases, the key enzymes in apoptosis, are synthesized as proenzymes and converted into active form by proteolytic cleavage. The residues on active site reorganize during the activation process as shown in the comparative studies of crystallographic structures of procaspase-7 and its mature form. On the other hand, the proenzyme itself has some activity. Aiming to characterize the activation process, the comparative kinetic study for the pro- and mature caspase-3 was performed. In 1/K(M) versus pH study, a residue with pKa of 6.89+/-0.13 was detected only in caspase-3. While Vmax versus pH kinetic results were consistent with the existence of a residue with pKa of 6.21+/-0.06 in procaspase-3 mutant (D9A/D28A/D175A) but not in caspase-3. In the inactivation assays with diethylpyrocarbonate, a residue (pKa, 6.61+/-0.05) could be determined only for caspase-3 whereas with iodoacetamide a residue with pKa value (6.01+/-0.05) could be assigned only for procaspase-3. Considering that those residues could be protected by caspase-3-specific inhibitor from the inactivation, the modifiers are histidine- and cysteine-specific, respectively, and the involvement of these residues in the characteristic catalytic dyad of caspases, the results indicate that the pKa values of the catalytic histidine and cysteine residues are changed during the activation process.