Natural variation of Arabidopsis response to nitrogen availability

Our understanding of plant growth in response to nitrogen (N) supply is mainly based on studies of mutants and transformants. This study explored the natural variability of Arabidopsis thaliana first to find out its global response to N availability and secondly to characterize the plasticity for growth and N metabolism among 23 genetically distant accessions under normal (N+), limited (N-), and starved (N0) N supplies. Plant growth was estimated by eight morphological traits characterizing shoot and root growth and 10 metabolic parameters that represented N and carbon metabolism. Most of the studied traits showed a large variation linked to genotype and nutrition. Furthermore, Arabidopsis growth was coordinated by master traits such as the shoot to root ratio of nitrate content in N+, root fresh matter and root amino acids in N-, and shoot fresh matter together with root thickness in N0. The 23 accessions could be gathered into four different groups, according to their growth in N+, N-, and N0. Phenotypic profiling characterized four different adaptative responses to N- and N0. Class 1 tolerated N limitation with the smallest decrease in shoot and root biomass compared with N+, while class 2 presented the highest resistance to N starvation by preferential increased root growth, huge starch accumulation, and high shoot nitrate content. In contrast, class 3 plants could tolerate neither N limitation nor N starvation. Small plants of class 4 were different, with shoot biomass barely affected in N- and root biomass unaffected in N0.     

Designing a highly immunogenic multi epitope based subunit vaccine against Bacillus cereus

ObjectiveSerious non-gastrointestinal-tract infections and food poisoning are caused by Bacillus cereus. Vaccination against B. cereus is very important. The aim of this study was to identify and analyze B and T cell epitopes for chromate transporter protein of the bacteria.MethodsMultiple sequence alignment with the Clustal Omega method was used to identify conserved regions and Geneious Prime was used to produce a consensus sequence. T and B cell epitopes were predicted by various computational tools from the NetCTL and Immune Epitope Database (IEDB), respectively.ResultsAltogether, 6 HTL cells and 11 CTL epitopes were predicted. This vaccine's molecular docking is done with Patch Dock and LigPlot to verify interactions. The immune server (C-IMMSIM) was used to develop In silico immune response in order to assess the multi-epitope vaccine's immunogenic profile.ConclusionWe designed universal vaccine against B. cereus responsible for food poisoning. The disease may be avoided with the aid of the proposed epitope-based vaccine.     

Mycobacterium tuberculosis TlyA Protein Negatively Regulates T Helper (Th) 1 and Th17 Differentiation and Promotes Tuberculosis Pathogenesis

Mycobacterium tuberculosis, the causative agent of tuberculosis, is an ancient pathogen and a major cause of death worldwide. Although various virulence factors of M. tuberculosis have been identified, its pathogenesis remains incompletely understood. TlyA is a virulence factor in several bacterial infections and is evolutionarily conserved in many Gram-positive bacteria, but its function in M. tuberculosis pathogenesis has not been elucidated. Here, we report that TlyA significantly contributes to the pathogenesis of M. tuberculosis. We show that a TlyA mutant M. tuberculosis strain induces increased IL-12 and reduced IL-1β and IL-10 cytokine responses, which sharply contrasts with the immune responses induced by wild type M. tuberculosis. Furthermore, compared with wild type M. tuberculosis, TlyA-deficient M. tuberculosis bacteria are more susceptible to autophagy in macrophages. Consequently, animals infected with the TlyA mutant M. tuberculosis organisms exhibited increased host-protective immune responses, reduced bacillary load, and increased survival compared with animals infected with wild type M. tuberculosis. Thus, M. tuberculosis employs TlyA as a host evasion factor, thereby contributing to its virulence.     

Hepatitis C virus resistance to interferon therapy: an alarming situation

Hepatitis C virus is presently a major public health problem across the globe. The main objective in treating hepatitis C virus (HCV) infection is to achieve a sustained virological response (SVR). Interferon-α (IFN-α) and pegylated interferon (PegIFN) in combination with Ribavirin (RBV) are the choice of treatment nowadays against chronic hepatitis C. There are several mechanisms evolved by the hepatitis C virus that facilitate the persistence of virus and further lead the patient’s status as non responder. Various factors involved in patient’s lack ofresponse to the therapy include: (1) viral factors, (2) host factors, (3) molecular mechanisms related to the lack of response and (4) social factors. Herein we have made an attempt to summarize all the related predictors of drug resistance in one article so that the future polices can be planned to overcome this obstacle and potential therapies can be designed by considering these factors.     

Synthesis, biological evaluation, and molecular docking studies of benzyl, alkyl and glycosyl [2-(arylamino)-4,4-dimethyl-6-oxo-cyclohex-1-ene]carbodithioates, as potential immunomodulatory and immunosuppressive agents

The immunomodulating properties of functionalized [2-(arylamino)-4,4-dimethyl-6-oxo-cyclohex-1-ene] carbodithioates and 6,6-dimethyl-4-(2-(propan-2-ylidene)hydrazinyl)-6,7-dihydro-2H-indazole-3(5H)-thione compounds have been investigated. Four of them, 13, 18, 19 and 20 inhibited PBMC proliferation induced by phytohemagglutinin (PHA) in a dose dependent manner with an IC(50) of ≤ 20 μM. The Th-1 cytokine, interleukin-2 (IL-2) in PHA/PMA-stimulated peripheral blood mononuclear cells (PBMCs) is significantly inhibited by 13, 19 and 20 with an IC(50) of 8.4 ± 0.4, 5.34 ± 0.15 and 4.9 ± 0.7 μM, respectively. They also inhibited the PMA/lipopolysaccharide-induced proinflammatory cytokines, IL-1β and TNF-α production in human monocytic leukemia cells (THP-1), by 86%, 46% and 59.2% for IL-1β and by 83.8%, 48.2% and 58.7% for TNF-α, respectively. Only 20 showed significant suppressive activity against the phagocyte oxidative burst in a dose dependent manner, with an IC(50) of 23.8 μM. LPS-induced nitrites in mouse macrophages were found to be inhibited by compounds 6, 8, 13-15 and 19 with an IC(50), which range between 7.7 and 63 μM. The cytotoxicity for the active compounds was also studied on Rat Wistar Hepatocyte cell line, CC1 and the Mouse Fibroblast cell line 3T3 NIH in the presence of compounds using a standard MTT assay. Furthermore, structural-activity relationship using automated docking software revealed that active compounds 7, 13 and 19, adapted the same binding mode, however the most active compound 20 is found deeply inserted within the ligand binding site of IL-2, as multiple hydrophobic and hydrophilic key interactions stabilize the compound inside the binding site, thus contributing higher activity.     

Immobilized Candida antarctica lipase B: Hydration, stripping off and application in ring opening polyester synthesis

This work reviews the stripping off, role of water molecules in activity, and flexibility of immobilized Candida antarctica lipase B (CALB). Employment of CALB in ring opening polyester synthesis emphasizing on a polylactide is discussed in detail. Execution of enzymes in place of inorganic catalysts is the most green alternative for sustainable and environment friendly synthesis of products on an industrial scale. Robust immobilization and consequently performance of enzyme is the essential objective of enzyme application in industry. Water bound to the surface of an enzyme (contact class of water molecules) is inevitable for enzyme performance; it controls enzyme dynamics via flexibility changes and has intensive influence on enzyme activity. The value of pH during immobilization of CALB plays a critical role in fixing the active conformation of an enzyme. Comprehensive selection of support and protocol can develop a robust immobilized enzyme thus enhancing its performance. Organic solvents with a log P value higher than four are more suitable for enzymatic catalysis as these solvents tend to strip away very little of the enzyme surface bound water molecules. Alternatively ionic liquid can work as a more promising reaction media. Covalent immobilization is an exclusively reliable technique to circumvent the leaching of enzymes and to enhance stability. Activated polystyrene nanoparticles can prove to be a practical and economical support for chemical immobilization of CALB. In order to reduce the E-factor for the synthesis of biodegradable polymers; enzymatic ring opening polyester synthesis (eROPS) of cyclic monomers is a more sensible route for polyester synthesis. Synergies obtained from ionic liquids and immobilized enzyme can be much effective eROPS.     

Regeneration of Centella asiatica plants from non-embryogenic cell lines and evaluation of antibacterial and antifungal properties of regenerated calli and plants

Background

The threatened plant Centella asiatica L. is traditionallyused for a number of remedies. In vitro plant propagation and enhanced metabolite production of active metabolites through biotechnological approaches has gained attention in recent years.

Results

Present study reveals that 6-benzyladenine (BA) either alone or in combination with 1-naphthalene acetic acid (NAA) supplemented in Murashige and Skoog (MS) medium at different concentrations produced good quality callus from leaf explants of C. asiatica. The calli produced on different plant growth regulators at different concentrations were mostly embryogenic and green. Highest shoot regeneration efficiency; 10 shoots per callus explant, from non-embryogenic callus was observed on 4.42 μM BA with 5.37 μM NAA. Best rooting response was observed at 5.37 and 10.74 μM NAA with 20 average number of roots per explant. Calli and regenerated plants extracts inhibited bacterial growth with mean zone of inhibition 9-13 mm diameter when tested against six bacterial strains using agar well diffusion method. Agar tube dilution method for antifungal assay showed 3.2-76% growth inhibition of Mucor species, Aspergillus fumigatus and Fusarium moliniformes.

Conclusions

The present investigation reveals that non-embryogenic callus can be turned into embryos and plantlets if cultured on appropriate medium. Furthermore, callus from leaf explant of C. asiatica can be a good source for production of antimicrobial compounds through bioreactor.     

Hepatocellular carcinoma: targeting of oncogenic signaling networks in TRAIL resistant cancer cells

Apoptotic response in hepatocellular carcinoma (HCC) cells is impaired because of interconnectivity of proteins into complexes and signaling networks that are highly divergent in time and space. TNF-related apoptosis-inducing ligand (TRAIL) has emerged as an attractive anticancer agent reported to selectively induce apoptosis in cancer cells. Although diametrically opposed roles of TRAIL are reported both as an inducer of apoptosis and regulator of metastasis, overwhelmingly accumulating experimental evidence highlighting apoptosis inducing activity of TRAIL is directing TRAIL into clinical trials. Insights from TRAIL mediated signaling in HCC research are catalyzing new lines of study that should not only explain molecular mechanisms of disease but also highlight emerging paradigms in restoration of TRAIL mediated apoptosis in resistant cancer cells. It is becoming progressively more understandable that phytochemicals derived from edible plants have shown potential in modelling their interactions with their target proteins. Rapidly accumulating in vitro and in-vivo evidence indicates that phytonutrients have anticancer activity in rodent models of hepatocellular carcinoma. In this review we bring to limelight how phytonutrients restore apoptosis in hepatocellular carcinoma cells by rebalancing pro-apoptotic and anti-apoptotic proteins. Evidence has started to emerge, that reveals how phytonutrients target pharmacologically intractable proteins to suppress cancer. Target-based small-molecule discovery has entered into the mainstream research in the pharmaceutical industry and a better comprehension of the genetics of patients will be essential for identification of responders and non-responders.