Background:The MtrB sensor kinase is a component of the essential MtrAB signal transduction system. Results: MtrB localizes to septa independent of phosphorylation; MtrB septal association and phosphorylation are necessary for cell division and expression of MtrA targets. Conclusion: MtrB septal localization and MtrA-regulon expression are linked. Significance: MtrB septal assembly triggers the activation of the MtrAB signal transduction pathway.

A vegetative insecticidal protein (VIP)-encoding gene from a local isolate of Bacillus thuringiensis has been cloned, sequenced, and expressed in Escherichia coli. The expressed protein shows insecticidal activity against several lepidopteran pests but is ineffective against Agrotis ipsilon. Comparison of the amino acid sequence with those of reported VIPs revealed a few differences. Analysis of insecticidal activity with N-and C-terminus deletion mutants suggests a differential mode of action of VIP against different pests.The gram-positive bacterium Bacillus thuringiensis is known to produce parasporal crystalline inclusions during the late exponential phase of growth (8). These crystals consist of several polypeptides, some of which are insecticidal or nematocidal. Upon ingestion by insects, these toxins are proteolytically activated, and after interaction with specific receptors at the mid-gut, they cause larval death (5). Since these toxins are highly specific, they are extremely useful in controlling targeted agricultural pests. Over the past several years, more than 100 different polypeptides have been identified, and several of them have been employed in insect management programs (8). The diversity, specificity, and usefulness of these insecticidal polypeptides have encouraged searches among diverse niches for new strains displaying novel insecticidal polypeptides. In addition to the crystal-associated toxic polypeptides, some insecticidal proteins produced during vegetative growth of the bacteria have also been identified. These proteins, called vegetative insecticidal proteins (VIPs), were reported from about 15% of the B. thuringiensis strains analyzed (2). We have screened several strains of B. thuringiensis obtained from soil samples collected from different parts of India for the presence of homologues of the VIP. Based on the reported gene sequences, we designed PCR DNA primers for the detection of the vip gene in strains held in our collection. As a result of the screening program, we have cloned, sequenced, and expressed a vegetative insecticidal toxin-coding gene from one of the isolates in our collection. The toxicity spectrum of the Escherichia coli-expressed recombinant protein has been evaluated against five lepidopteran pests. By deletion analysis, we have characterized the minimal toxic polypeptide segment that retains insecticidal activity. The toxicity of deleted VIP against lepidopteran pests suggested a differential mode of action against different pests.Bacterial strains and plasmids. Different isolates of B. thuringiensis were enriched from soil samples collected from different geographical locations within India. For routine use in the laboratory, the isolates were maintained in nutrient medium (Difco), and for long-term storage, the isolates were stored as glycerol stocks at Ϫ70°C. E. coli strain M15 was obtained from Qiagen (Braunschweig, Germany) and, when required, was grown in Luria-Bertani (LB) medium at 37°C with shaking at 200 rpm.Oligonucleotide PCR primers. Primers to sc...

Significance of preharvest salicylic acid (SA) treatments on maturity, quality and postharvest life of grape cv. Flame Seedless were studied during two years. The experiment was performed on 12-year old own rooted, grapevines planted at 3 m × 3 m spacing trained on overhead system. Vines were treated with aqueous solutions of SA (0.0, 1.0, 1.5 and 2.0 mM) at pea stage and at veraison. After harvesting, clusters were divided into two lots in which one was subjected to initial quality evaluation, while the other was stored in cold room (3-4 °C, 90-95 % RH) for evaluation of postharvest quality. SA at the dose of 1.5 and 2.0 mM hastened berry maturity by 3 to 5 days, produced less compact bunches alongside larger berries in contrast to control and the lowest dose. The same doses effectively maintained peel colour, higher firmness, lower pectin methyl esterase activity and electrolyte leakage alongside suppressing degradation of TSS and TA during cold storage. These two doses also exhibited higher efficacy on maintaining anthocyanins, phenols and organoleptic properties while reducing weight loss, rachis browning and decay incidence. Correlation analysis demonstrated that many quality parameters are interdependent. In conclusion, preharvest spray of 1.5 mM SA proved to be an effective means of improving quality and extending postharvest life of grape cv. Flame Seedless.

cBacterial cell division and cell wall synthesis are highly coordinated processes involving multiple proteins. Here, we show that Rv0008c, a novel small membrane protein from Mycobacterium tuberculosis, localizes to the poles and on membranes and shows an overall punctate localization throughout the cell. Furthermore, Rv0008c interacts with two proteins, CrgA and Wag31, implicated in peptidoglycan (PG) synthesis in mycobacteria. Deletion of the Rv0008c homolog in M. smegmatis, MSMEG_0023, caused bulged cell poles, formation of rounded cells, and defects in polar localization of Wag31 and cell wall synthesis, with cell wall synthesis measured by the incorporation of the [ 14 C]N-acetylglucosamine cell wall precursor. The M. smegmatis MSMEG_0023 crgA double mutant strain showed severe defects in growth, viability, cell wall synthesis, cell shape, and the localization of the FtsZ, FtsI, and Wag31 proteins. The double mutant strain also exhibited increased autolytic activity in the presence of detergents. Because CrgA and Wag31 proteins interact with FtsI individually, we believe that regulated cell wall synthesis and cell shape maintenance require the concerted actions of the CrgA, Rv0008c, FtsI, and Wag31 proteins. We propose that, together, CrgA and Rv0008c, renamed CwsA for cell wall synthesis and cell shape protein A, play crucial roles in septal and polar PG synthesis and help coordinate these processes with the FtsZ-ring assembly in mycobacteria. Since its reemergence in the early 1990s, tuberculosis caused by Mycobacterium tuberculosis remains a leading cause of global morbidity and mortality. With nearly 10 million new cases reported each year and 2 billion people infected, as well as the emergence of extensively drug-resistant and completely drug-resistant strains, sustained interest in improved control measures and tuberculosis research is crucial (4, 40). These reports emphasize the importance of understanding the basic biology of the pathways needed for pathogen proliferation, namely, DNA replication and cell division, and the development of novel strategies for combating M. tuberculosis infection (27).Cell division in bacteria is accomplished by the coordinated actions of multiple proteins that form a septal ring in the middle of a dividing cell. FtsZ, a cytoskeletal protein and a GTPase, initiates the cytokinesis process by the GTP-dependent midcell assembly of a ring structure called the Z ring (2). Constriction of the Z ring, driven by the GTPase activity of FtsZ, initiates cell division. During various stages of cell division, FtsZ interacts with a number of proteins, and these interactions modulate its midcell localization, membrane tethering, biochemical activities, and influence on the assembly of other septal ring members, including some proteins involved in peptidoglycan (PG) synthesis (reviewed in reference 2). Recent data also suggest that, at least in some bacteria, FtsZ plays a role in guiding cell wall synthesis (1, 37).In the last decade, significant advancements have been made not only ...

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The bacterium Bacillus thuringiensis produces ICPs (insecticidal crystal proteins) that are deposited in their spore mother cells. When susceptible lepidopteran larvae ingest these spore mother cells, the ICPs get solubilized in the alkaline gut environment. Of approx. 140 insecticidal proteins described thus far, insecticidal protein Cry1Ac has been applied extensively as the main ingredient of spray formulation as well as the principal ICP introduced into crops as transgene for agricultural crop protection. The 135 kDa Cry1Ac protein, upon ingestion by the insect, is processed successively at the N- and C-terminus by the insect midgut proteases to generate a 65 kDa bioactive core protein. The activated core protein interacts with specific receptors located at the midgut epithilium resulting in the lysis of cells and eventual death of the larvae. A laboratory-reared population of Helicoverpa armigera displayed 72-fold resistance to the B. thuringiensis insecticidal protein Cry1Ac. A careful zymogram analysis of Cry1Ac-resistant insects revealed an altered proteolytic profile. The altered protease profile resulted in improper processing of the insecticidal protein and as a consequence increased the LC50 concentrations of Cry1Ac. The 135 kDa protoxin-susceptible insect larval population processed the protein to the biologically active 65 kDa core protein, while the resistant insect larval population yielded a mixture of 95 kDa and 68 kDa Cry1Ac polypeptides. N-terminal sequencing of these 95 and 68 kDa polypeptides produced by gut juices of resistant insects revealed an intact N-terminus. Protease gene transcription profiling by semi-quantitative RT (reverse transcription)-PCR led to the identification of a down-regulated HaSP2 (H. armigera serine protease 2) in the Cry1Ac-resistant population. Protease HaSP2 was cloned, expressed and demonstrated to be responsible for proper processing of insecticidal protoxin. The larval population displaying resistance to Cry1Ac do not show an altered sensitivity against another insecticidal protein, Cry2Ab. The implications of these observations in the context of the possibility of development of resistance and its management in H. armigera to Cry1Ac through transgenic crop cultivation are discussed.

AI can be harnessed for forecasting the spread of virus and developing early warning systems by extracting information from social media platforms, calls and news sites and provide useful information about the vulnerable regions and for prediction of morbidity and mortality "

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