An Eco-Friendly Production of a Novel and Highly Active Endo-1,4-beta-xylanase from Aspergillus clavatus

Aims: Here, we describe a novel way to produce an endo-1,4-beta-xylanase from Aspergillus clavatus using paper and pulp industry waste. Methodology: Optimal Aspergillus clavatus NRRL1 cultivation conditions were evaluated using minimal medium with different concentrations (1 to 10%) of paper sludge pretreated with HCl, during different periods (1 to 14 days), with different pH values (3.0; 3.5; 4.0; 4.5; 5.0; 5.5; 6.0; 6.5; 7.0; 7.5 and 8.0), different temperatures (25, 30, 35, and 40 ºC) and different mixing conditions (static and stirring). After that, the enzyme activity was determined by DNS (3,5-dinitrosalicylic acid), protein concentration was quantified by Bradford, SDS-PAGE was performed to evaluate the molecular mass, and TLC observed hydrolysis products. Results: The enzyme showed a molecular mass of 25 kDa, and its production has been highly improved by optimizing culture conditions. The best activity of this enzyme was obtained when A. clavatus was cultivated for 5 days, at 120 rpm, 5% paper sludge, pH 6.0, and 35 ºC. The degradation profile of the beechwood xylan by the crude extract containing the GH11 xylanase showed xylotriose as the main product, but xylotetraose and xylobiose were also produced in significant amounts. Conclusion: In addition to the fact that this xylanase has the property of producing large quantities of XOS (mainly xylotriose), it has the advantage of being obtained from recyclable waste of the pulp and paper industry. These facts confer great potential for future biotechnological and industrial applications.

Mycoflora associated with diseased rice grains in Bangladesh and their pathogenic potentiality

Fifty six spotted rice grain samples of four commercially cultivated rice varieties namely BRRI 28, 29, Kalijira and Pajam were collected from 14 different districts of Bangladesh. Forty rice samples (Hybrid 2,3,4, BR7,11,12,14,16,22,23,25,26and BRRI28 to BRRI 55) were also collected from Bangladesh Rice Research Institute at Joydevpur. Twenty-fivespecies of fungi belonging to 15 genera were associated with these rice varieties. The isolated fungi were Alternaria alternata, Aspergillus clavatus, A. flavus, A. fumigatus, A.niger, A. ochraceus, A.oryzae, A. terreus, Chaetomium globosum, Cladosporium cladosporioides, Colletotrichum gloeosporioides, Curvularia lunata, C. lunata var. aeria, Drechslera oryzae, Fusarium moniliforme, F. oxysporum, F. solani, Microdochium oryzae, Nigrospora oryzae, Penicillium spp., Pestalotiopsis guepinii, Sarocladium oryzae and Trichoderma viride. Amongst these fungi nine i.e. Alternaria alternata (Fr.) Keissler, Aspergillus flavus Link, Curvularia lunata (Wakker) Boedijn, Drechsler aoryzae Breda de Haan (Subramanian and Jain), Fusarium moniliforme Sheldon, F. solani (Mart.) Sacc., Microdochium oryzae (Hashloka and Yokogi) Sam. and Hal., Pestalotiopsis guepinii (Desm.) Stay. and Sarocladium oryzae (Sawada) W. Gams and D. Hawks were found to be pathogenic to rice seeds. The most predominant fungus was D. oryzae which was followed by A. flavus and the least incidence was observed in case of F. solani and P. guepinni. Bioresearch Commu. 7(1): 932-940, 2021 (January)

Immunological detection of AcAMP antimicrobial peptide secreted by Aspergillus clavatus

Background and Objectives: Aspergillus clavatus antimicrobial peptide (AcAMP) is a fungi-derived peptide with a broad spectrum of activity against pathogenic bacteria and fungi. Natural antimicrobial peptides, including AcAMP, have attracted many attentions in the development of new natural antibiotics against pathogenic bacteria, especially multidrug resistant ones. Materials and Methods: In the present study, acamp gene was codon-optimized and chemically synthesized in pUC57 cloning vector, subcloned into pET28a (+) expression vector and transferred into competent Escherichia coli BL21 (DE3) cells. The expression of AcAMP was induced by addition of Isopropyl β- d-1-thiogalactopyranoside (IPTG) and the expressed peptide was purified by Ni-NTA. BALB/c mice were immunized with the purified peptide and the ability of the immunized mice sera for the detection of the native AcAMP secreted by A. clavatus IRAN 142C was examined through ELISA and Western blotting techniques. Results: Both ELISA and Western blotting demonstrated the ability of the sera of the immunized mice to detect the native AcAMP. Conclusion: The results of the present work show that the raised antibody against recombinant AcAMP can be used to detect AcAMP peptide, an issue which paves the way to develop detection kits for the detection of AcAMP-producing organisms, purification of this valuable peptide for further investigations.

Synthesis, Characterization, Single-Crystal X-ray Structure and Biological Activities of [(Z)-N′-(4-Methoxybenzylidene)benzohydrazide–Nickel(II)] Complex

(Z)-N′-(4-methoxybenzylidene)benzohydrazide (HL) and its Ni(II) complex (Ni(II)-2L) were synthesized using eco-friendly protocols. The single X-ray crystal structure of Ni(II)-2L was solved. Moreover, the structural properties were evaluated using Fourier transform infrared, proton nuclear magnetic resonance, mass, and Ultraviolet/Visible spectroscopy. The diamagnetic and thermal stability were assessed using magnetic susceptibility and thermogravimetric analysis, respectively. The biological activities of both HL and Ni(II)-2L (62.5–1000 μg/mL) against Gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial and fungal (Candida albicans, Aspergillus niger, and Aspergillus clavatus) species were studied using the minimum inhibitory concentration (MIC) tests method in reference to Gentamycin and Nystatin standard drugs, respectively. The results revealed an affordable, environmentally friendly, and efficient synthetic method of HL using water as a green solvent. The Ni(II)-2L complex crystallized in a distorted square planar, P21/n space group, and one Ni(II) to two bidentate negatively charged ligand ratio. The analysis of biological activity revealed higher activity of the complex against S. aureus and S. pyogenes (bacteria) and A. niger and A. clavatus (fungi) compared to the ligand. However, the highest activity was at a MIC of 62.5 μg/mL for the complex against S. pyogenes and for the ligand against E. coli. Therefore, both HL and Ni(II)-2L could be promising potential antimicrobials and their selective activity could be an additional benefit of these bioactive materials.

Microwave Induced one Pot Ugi Multicomponent Reaction of Fluoroquino lone Scaffolds: Their Biological Evaluation

Microwave irradiated facile and efficient process for one pot Ugi multicomponent reaction of a novel series of fluoroquinolone scaffolds is described here. On the basis of this approach, a new route to synthesize this privileged scaffolds were designed with higher yields, a clean procedure, time efficient and simple work-up. Our aim is to develop a biologically active fluoroquinolone scaffolds by microwave induced one pot Ugi multicomponent reaction. All the synthesized molecules were characterized by IR, 1H NMR, 13C NMR, and Mass spectra. The antimicrobial activity of synthesized compounds was screened against two Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), two Grampositive bacteria (Staphylococcus aureus, Streptococcus pyogenes), and three fungi (Candida albicans, Aspergillus niger, Aspergillus clavatus) utilizing the MIC (Minimal Inhibitory Concentration) method and antitubercular activity H37Rv utilizing L. J. Slope method. Some of these novel derivatives demonstrate moderate to good in vitro antibacterial, antifungal and antitubercular activities.

Airborne Aspergillus at some rural areas adjoining to Raipur city (C.G.) India

Increased urbanization and industrialization in recent time has made a significant impact on air quality of the area. The atmosphere is rich in propagule of different fungal species. The investigation on airborne Aspergillus contribution was conducted in Periphery of Raipur city from February, 2018 to March, 2019 with the help of gravity petriplate containing PDA (Potato Dextrose Agar) medium. In this study, total 11 species of Aspergillus were recorded. The percentage frequency and percentage contribution of different Aspergillus species were different in different seasons. Aspergillus niger was most frequent throughout the year followed by Aspergillus fumigatus, A. flavus, and A. nidulans etc. While Aspergillus clavatus, and A. versicolor, A. aculeatus were the least frequent species. The result indicated the highest percentage contribution of Aspergillus niger (43.29 percent) followed by A. fumigatus (9.02percent), A. flavus (8.42 percent) while A. clavatus (0.21 percent). The objective of the studies was to determine a seasonal variation in concentrations of Aspergillus on the basis of meteorological parameters.