Screening of phytotoxicity of Alternaria macrospora MKP1 against Parthenium hysterophorus L.

Parthenium hysterophorus L. an exotic, pernicious weed is considered as one of the most troublesome weeds for agricultural sector by virtue of its high ecological amplitude and adaptability. Microbes and their by-products are now proved to be a worthy alternative to toxic chemicals used for weed management. Alternaria macrospora MKPI was isolated from the parthenium leaves infected with leaf blight and found pathogenic to the weed. The herbicidal potential of cell free culture filtrate of A. macrospora MKP1 has been tested against parthenium by employing detached leaf bioassay and seed germination bioassay and a significant damage was exhibited by the cultural filtrate of pathogen to the parthenium leaves and seeds.     

Characterization of a novel xylanase from Armillaria gemina and its immobilization onto SiO2 nanoparticles

Enhanced catalytic activities of different lignocellulases were obtained from Armillaria gemina under statistically optimized parameters using a jar fermenter. This strain showed maximum xylanase, endoglucanase, cellobiohydrolase, and β-glucosidase activities of 1,270, 146, 34, and 15 U mL^?1, respectively. Purified A. gemina xylanase (AgXyl) has the highest catalytic efficiency (k _cat/K _m?=?1,440 mg?mL^?1?s^?1) ever reported for any fungal xylanase, highlighting the significance of the current study. We covalently immobilized the crude xylanase preparation onto functionalized silicon oxide nanoparticles, achieving 117 % immobilization efficiency. Further immobilization caused a shift in the optimal pH and temperature, along with a fourfold improvement in the half-life of crude AgXyl. Immobilized AgXyl gave 37.8 % higher production of xylooligosaccharides compared to free enzyme. After 17 cycles, the immobilized enzyme retained 92 % of the original activity, demonstrating its potential for the synthesis of xylooligosaccharides in industrial applications.     

Host-induced silencing of Mi-msp-1 confers resistance to root-knot nematode Meloidogyne incognita in eggplant

RNA interference (RNAi)-based host-induced gene silencing (HIGS) is emerging as a novel, efficient and target-specific tool to combat phytonematode infection in crop plants. Mi-msp-1, an effector gene expressed in the subventral pharyngeal gland cells of Meloidogyne incognita plays an important role in the parasitic process. Mi-msp-1 effector is conserved in few of the species of root-knot nematodes (RKNs) and does not share considerable homology with the other phytonematodes, thereby making it a suitable target for HIGS with minimal off-target effects. Six putative eggplant transformants harbouring a single copy RNAi transgene of Mi-msp-1 was generated. Stable expression of the transgene was detected in T₁, T₂ and T₃ transgenic lines for which a detrimental effect on RKN penetration, development and reproduction was documented upon challenge infection with nematode juveniles. The post-parasitic nematode stages extracted from the transgenic plants showed long-term RNAi effect in terms of targeted downregulation of Mi-msp-1. These findings suggest that HIGS of Mi-msp-1 enhances nematode resistance in eggplant and protect the plant against RKN parasitism at very early stage.

     

Genetic and Epigenetic Variation across Genes Involved in Energy Metabolism and Mitochondria of Chinese Hamster Ovary Cell Lines

The increasingdemandfor biopharmaceutical products drives the search for efficient cell factories that are able to sustainably support rapid growth, high productivity, and product quality. As these depend on energy generation, here the genomic variation in nuclear genes associated with mitochondria and energy metabolism and the mitochondrial genome of 14 cell lines is investigated. The variants called enable reliable tracing of lineages. Unique sequence variations are observed in cell lines adapted to grow in protein‐free media, enriched in signaling pathways or mitogen‐activated protein kinase 3. High‐producing cell lines bear unique mutations in nicotinamide adenine dinucleotide (NADH) dehydrogenase (ND2 and ND4) and in peroxisomal acyl‐CoA synthetase (ACSL4), involved in lipid metabolism. As phenotypes are determined not only by functional mutations, but also by the exquisite regulation of expression patterns, it is not surprising that ≈50% of the genes investigated here are found to be differentially methylated and thus epigenetically controlled, enabling a clear distinction of high producers, and cells adapted to a minimal, glutamine (Gln)‐free medium. Similar pathways are enriched as those identified by genome variation. This strengthens the hypothesis that these phenomena act together to define cell behavior.     

Potential of bacterial culture media in biofabrication of metal nanoparticles and the therapeutic potential of the as-synthesized nanoparticles in conjunction with artemisinin against MDA-MB-231 breast cancer cells

In the recent past, various groups have proposed diverse biocompatible methods for the synthesis of metal nanoparticles (NPs). Besides culture biomass, culture supernatants (CS) are increasingly being explored for the synthesis of NPs; however, with the ever-increasing exploration of various CS in the biofabrication of NPs, it is equally important to explore the potential of various culture media (CMs) in the synthesis of metal NPs. Considering these aspects, in the present investigation, we explore the possible applicability of various CMs in the biofabrication of metal NPs. The synthesis of NPs was primarily followed by UV/VIS spectroscopy, and, thereafter, the NPs were characterized by various physiochemical techniques, including EM, EDX, FT_IR, X-ray diffraction, and DLS measurements, and finally, their anticancer potentialities were investigated against breast cancer. In addition, the NPs were examined in conjunction with artemisinin for therapeutic benefits against aggressive and highly metastatic MDA-MB-231 breast cancer cells. Cumulatively, the results of the present study collated the potentials of various bacterial CMs in the biofabrication of metal NPs and ascertained the efficacy of the as-synthesized silver nanoparticles, especially the combinatorial entity as intriguing breast cancer therapeutics. The data of the present study plausibly assist in advancing the therapeutic applicability of the combinatorial amalgam against aggressive and highly metastatic MDA-MB-231 breast cancer cells.     

HHV-5 epitope: A potential vaccine candidate with high antigenicity and large coverage

Outbreak of Human Herpes virus-5 (HHV-5) infection in emerging countries has raised worldwide health concern owing to prevalence of congenital impairments and life threatening consequences in immunocompromised individuals. Thus, there lies an impending need to develop vaccine against HHV-5. HHV-5 enters into host cells with the help of necessary components glycoprotein B (gB) and H/L. In this study, the conformational linear B-cell and T-cell epitopes for gB of HHV-5 have been predicted using conformational approaches, for their possible collective use as vaccine candidates. We examined epitope’s interactions with major histocompatibility complexes using molecular docking and also investigated their stable binding with specific toll like receptor-2 (TLR2), present on host cells during HHV-5 infection. Predicted MHC-I epitope ‘LVAIAVVII’ with high antigenicity and large coverage of HLA alleles was found to superimpose on MHC-II epitope (Rank 1) and was also identified to be the core sequence of putative B cell epitope ‘ILVAIAVVIITYLI’. Resulting epitope was found to have consistent interaction with TLR2 during long term (100?ns) MD run. We also validated this nonamer epitope for its dissimilarity with human genome and high population coverage, suggesting it to be a potential vaccine candidate with higher coverage for both the MHC alleles of Indian population.

Communicated by Ramaswamy H. Sarma     

Mycobacterial proteins--immune targets for antituberculous subunit vaccine

Cellular and humoral immunity induced by Mycobacterium tuberculosis has led to identification of newer vaccine candidates, but despite this, many questions concerning the protection against tuberculosis remain unanswered. Recent progress in this field has centered on T cell subset responses and cytokines that these cells secrete. There has been a steady progress in identification and characterization of several classes of major mycobacterial proteins which includes secretory/export proteins, cell wall associated proteins, heat shock proteins and cytoplasmic proteins. The protein antigens are now believed to represent the key protective immunity inducing antigens in the bacillus. In this review, various mycobacterial protein antigens of vaccination potential are compared for their efficacy in light of current immunological knowledge.     

Effect of pH on infectivity and morphology of ecotropic moloney murine leukemia virus

A number of factors affect the infectivity of retroviruses. The effect of pH on infectivity and morphology of ecotropic moloney murine leukemia virus (MoMuLV) was determined in this work. The ecotropic MoMuLVs were found to remain infectious at a narrow pH range from 5.5 to 8.0. Our experiments indicated that the viruses were inactivated swiftly at lower or higher pH. Within 5 min of exposure to pH 4 about 95% of the viruses lost infectiousness. The viruses were completely inactivated after exposure to pH < 3 or pH >11 for 5 min. The inactivation of MoMuLV was irreversible. Electron microscopy revealed that ecotropic MoMuLV remained round-shaped at pH between 7.0 and 5. They became irregular with a convex head at pH < 4. At pH 2, virtually all virion particles were penetrated by stains, causing the accumulation of heavy metals inside the particles. The penetration of heavy metal inside the particles indicated the disassociation of the lipid bilayer of the viruses at low pH. A FACS-based screening strategy for selecting high-titer retrovirus producing cell lines is also presented in this report.