Antimicrobial Activity of Biosynthesized Silver Nanoparticles Decorated Silica Nanoparticles Abstract The production of cheap and effective compound for medicinal application is a major challenge for scientific community. So, several biological materials have been explored for the possible application in material synthesis which are useful in biomedical uses. Here, biomolecules from green tea leaves were functionalized on the surface of silicon dioxide nanoparticles (GSiO2 NPs). Next, the decoration silver (Ag) NPs on the surface of the GSiO2 NPs was observed in very short time of incubation in aqueous AgNO3. Ultraviolet–visible spectroscopy confirmed the formation of Ag NPs and the high-resolution transmission and scanning electron microscopies confirmed the decoration of spherical Ag NPs of 10 to 15 nm size on the surface of GSiO2 NPs. The antimicrobial activity of the Ag–GSiO2 NPs was determined against Staphylococcus aureus and Escherichia coli. The Ag–GSiO2 NPs displayed sustainable antimicrobial activity compared to Ag ions. The results indicate the potential value of Ag–GSiO2 NPs in surgical material and food processing.

Influence of Metal Ions on the Immobilization of β-Glucosidase Through Protein-Inorganic Hybrids Abstract Immobilization of enzymes through metal-based system is demonstrated as a promising approach to enhance its properties. In this study, the influence of metals ions, including copper, cobalt and zinc (Zn) on the immobilization of β-glucosidase (BGL) through the synthesis of protein-inorganic hybrid was evaluated at 4 °C. Among these metal ions-based hybrids, Zn showed the highest encapsulation yield and relative activity of 87.5 and 207%, respectively. Immobilized BGL exhibited higher pH and temperature stability compared to free form. Thermal stability of hybrid improved up to 26-fold at 60 °C. After 10 cycles of reuse, immobilized enzyme retained 93.8% of residual activity. These results suggested that metal ions played a significant role in the enzyme immobilization as a protein-inorganic hybrid. Overall, this strategy can be potentially applied to enhance the properties of enzymes though effective encapsulation for the broad biotechnological applications.

Development of Rapid and Specific Detection for the Human Aichivirus A Using the Loop-Mediated Isothermal Amplification from Water Samples Abstract Human Aichivirus A (AiV-A) is classified as a Kobuvirus, group IV positive sense single strand RNA viruses. The first outbreak of AiV-A was reported from Aichi Prefecture, Japan in 1989. AiV-A exists not only among clinical patients, such as diarrhea, but also in a variety of water environments, as its occurrence is reported across a wide geographical range, from developing to advanced countries. For diagnose of AiV-A from water samples, mostly polymerase chain reaction (PCR) system have been developed. However, loop-mediated isothermal amplification (LAMP) assay has not been applied. In this study, developed a LAMP method to achieve a rapid, specific and highly sensitive detection of AiV-A. The method developed in this study is aimed specifically at AiV-A. Through a specific and non-specific selection and sensitivity test process for the five prepared LAMP primer sets, one primer set and optimum reaction temperature were selected. A newly developed method was more rapid (approximately 2–8 h), specific and equivalent detection of AiV-A than with the conventional PCRs. In addition, confirm system of positive LAMP reaction was developed by using the restriction enzyme Aci I and Hae III. For evaluation and verification of developing LAMP assay, a was applied to twenty cDNA from groundwater samples. This study proved rapid and specific diagnosis of AiV-A from water samples, and it is also demanded to be applicable to other environmental, clinical and food samples.

Scale Up Studies for Polyhydroxyalkanoate Production by a Bacillus flexus Strain with Industrial Potential Abstract Polyhydroxyalkanoates (PHA) are synthesized by bacteria under unfavourable growth conditions like excess of carbon over nitrogen, coupled with oxygen limitation. The PHA polymers of microbial origin are diverse in chemical composition and material properties. A bioprocess for PHA production by indigenously isolated Bacillus flexus MTCC 12841 was devised and optimized at a laboratory fermentor scale. Fermentation strategies that involved modifications in some parameters like aeration, agitation, temperature, nutrient feeding or changes in C:N ratio led to substantial improvement of 59% in PHA production reaching highest concentration of 9.73 g/L. Biomass too was enhanced to 15.70 g/L equivalent to 126% increase over the optimized shake flask runs. PHA (Yp/s) and biomass (Yx/s) yields were found to be 0.32 and 0.51 g/g respectively, indicating good carbon utilization efficiency. The characterization of polymer by GC–MS revealed that the culture produced poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) as a co-polymer. The novelty of the research findings lies in the demonstration of increased production of PHA at lab fermentor level coupled with the identification of the natural ability of the strain to also produce PHBV without any need for exogenous addition of precursors. The fermentation process as well as the strain may be subjected to further optimization to increase the PHA production as well as to increase the % of HV content in the co-polymer.

Study of Waste Products as Supplements in the Production and Quality of Pleurotus ostreatus var. Florida Abstract Among the cultivated mushroom, the genus Pleurotus is the second largest produced worldwide and the most produced in Brazil. The application of agricultural by-products (wastes) as substrate supplement is an effective approach to generate quality food while promoting a circular economy in agriculture. The manuscript evaluates the three key aspects of this practice: (1) the response of different mushroom strains to supplementation, (2) the use of agricultural by-products with different N content, and (3) the efficacy of certain preliminary treatments applied to the supplements. To this end, production and nutritional quality of the mushroom were tested along the crop cycle. Compared to the control substrate, the yield increased by 11, 26, 30 and 42% in the first flush and by 86 and 31% in the second flush. Supplementation resulted in an increment of the fiber and protein content of mushroom and a decline of carbohydrate and lipid content of mushroom.

Differential Expression of the apsXRS System by Antimicrobial Peptide LL-37 in Commensal and Clinical Staphylococcus epidermidis Isolates Abstract The three-component apsXRS system senses and responds to cationic antimicrobial peptides (CAMPs), which induces the expression of the dlt operon and the genes mprF and vrafG, modifying the surface net charge in Staphylococcus epidermidis, resulting in the repulsion of CAMPs. The apsXRS system has been only studied in the S. epidermidis 1457 strain, and there are no studies of prevalence and level of expression of apsXRS in commensal and clinical isolates. From 60 isolates, those selected from commensal healthy skin (n = 20), commensal healthy conjunctive (n = 10), and clinical ocular infection (n = 30) presented the apsX, apsR, and apsS genes in their genomes. Constitutive expression of apsX, apsR, and apsS genes was determined by RT-qPCR in all isolates. It was found that expression of apsX, apsR, and apsS was 3.3–5.9-fold higher in commensal isolates stimulated with LL-37 (15 µg/mL) than in clinical isolates. Similarly, expression of the dlt operon and the genes mprF, and vraFG was 8–10-fold higher in commensal isolates than in clinical. However, LL-37 did not increase the addition of lysine in the phospholipids of the cytoplasmic membrane in any of the isolates. Mutations in the apsS loop region, apsR, and their promoter sequence were not found. These results demonstrated that apsXRS system is essential in all isolates for its constitutive expression; however, LL-37 caused an increase of apsXRS expression in commensal isolates, suggesting that S. epidermidis isolates do not respond in the same way to the presence of LL-37.

Foliar Application of Iron Fortified Bacteriosiderophore Improves Growth and Grain Fe Concentration in Wheat and Soybean Abstract Iron (Fe) is one of the key micronutrients essential for plant growth, yield and quality. Wheat (Triticum aestivum) and soybean (Glycine max) are important food crops but have relatively low Fe content in grains/seeds. Foliar application of Fe-invigorated bacteriosiderophore might increase Fe content in grain as well as improve overall plant growth. From a preliminary experiment conducted on soybean using 20 bacterial strains, Arthrobacter sp. (low siderophore producing) and Lysinibacillus fusiformis (high siderophore producing) were selected based on amount of siderophore produced and response of plants. This result was validated on field grown soybean and wheat crops by applying bacteriosiderophore with or without Fe on foliage. Siderophore was applied at flowering stage in both crops and observations were recorded on the sixth day after foliar spray. Significantly higher shoot biomass, area of leaves or flag leaf and tissue Fe concentration was recorded by siderophore produced by L. fusiformis with Fe as compared to Arthrobacter sp. In comparison to control (water), application of Fe fortified bacterial siderophore resulted not only in increased grain yield by 45% and 28% in wheat and soybean, respectively but also enhanced Fe concentration in grains by 1.7-fold in soybean to 2.0-fold in wheat. Partitioning of Fe in grain was higher in wheat as compared to soybean after foliar spray. Thus, we reported for the first time that bacteriosiderophore with added Fe as foliar application could be an economical and targeted agronomic approach towards Fe fortification in crop plants.

Mycelial form of dimorphic fungus Malassezia species dictates the microbial interaction Abstract Dandruff is one of the most common clinically manifested and studied scalp disorders. It has been associated with both bacteria and fungi. Bacteria and fungi inhabiting the scalp are known to influence each other and manifestation of dandruff. Fungal and bacterial isolates from scalp epithelial flakes (dandruff) were identified by rDNA sequencing. Local oils were tested for fungal and bacterial inhibition, interaction and biofilm formation, cell–cell interactions were studied by auto aggregation and surface thermodynamics studies. The isolates Bacillus sp.C2b1 (MK036745) and Malassezia sp. C2y1 (MK036746) were inhibited by Mahabhrungraj oil. The fungal morphological switch was evident and dependent on nutrition. Cell aggregation studies suggested the interaction of bacteria with yeast (non-pathogenic) phase of the fungus. Bacterial and yeast cells were found to be compatible for biofilm formation. The fungal mycelial surfaces were found to be conducive for interaction with both bacterial cells and yeast forms. The results here indicate the significance of mycelial phase of scalp-isolated fungus in interaction with the bacterial surfaces and also with self-yeast phase surface. This is the first report of the interaction between scalp-isolated microorganisms with respect to their surface interaction capabilities.

Efficacy of a Ruminal Bacteriocin Against Pure and Mixed Cultures of Bovine Mastitis Pathogens Abstract Bacteriocins have been suggested as an alternative to conventional antibiotics for the prevention and treatment of mastitis infections. Predominant bacteria associated with bovine mastitis (n = 276 isolates) were evaluated for their susceptibility to bovicin HC5, a ruminal bacteriocin produced by Streptococcus equinus HC5. Bovicin HC5 inhibited most (> 80%) of the streptococcal and staphylococcal strains tested, but showed no effect against Escherichia colistrains. Susceptibility and resistance testing indicated that approximately 95% of the S. aureus strains were inhibited by concentrations of bovicin HC5 varying from 40 to 2560 AU ml−1. Bovicin HC5 (62.50 AU ml−1) also inhibited the growth of aerobic and anaerobic mixed cultures of S. aureus and S. agalactiae, but the combination with 0.25 mmol l−1 of EDTA showed even greater bactericidal activity. These results demonstrate that bovicin HC5 is effective against the most prevalent pathogens found in contagious udder infections and could complement the use antibiotics in mastitis prophylaxis and therapy.

Recombinant l -Asparaginase II from Lactobacillus casei subsp. casei ATCC 393 and Its Anticancer Activity Abstract l-asparaginases from bacterial origin are employed extensively in leukemic treatment and food industry. The present study focuses on the characterization of the recombinant l-asparaginase II from Lactobacillus casei subsp. caseiATCC 393 cloned into Escherichia coli expression system and purified using Ni–NTA chromatography. The recombinant l-asparaginase as a monomer had a molecular weight of 35 kDa. The enzyme was active from 10 to 80 °C with the optimum at 40 °C. The enzyme retained its activity at 28 °C and 37 °C up to 24 h. The enzyme had optimum pH of 6 and retained 50% activity till 18 h. The Km of the recombinant enzyme was 0.01235 mM and Vmax1.576 mM/min. The half life of recombinant l-asparaginase II in human serum was 44 h and trypsin was for 15 min. The LC–MS/MS analysis revealed the molecular weight of 35,050 and pI of 5.64. The secondary structure prediction using CD spectroscopy for the recombinant enzyme showed 33.5% α-helix, 66.5% turn and 0% β sheets. The cytotoxicity of the recombinant enzyme was analysed against MOLT 3, Jurkat E6.1 and K-562 with the IC 50 value of 30, 62.5 and 50 µg/ml.