Current Issue : April - June Volume : 2013 Issue Number : 2 Articles : 6 Articles
This study was performed to isolate actinomycete colonies having antibacterial activity from soil samples collected from different\nplaces around Rajshahi, Bangladesh. Thirty actinomycete colonies were isolated in pure culture fromfive soil samples using Starchcasein-\nnitrate-agar medium. The isolates were grouped in five color series based on their aerialmycelia color and screened for their\nantibacterial activity against a range of test bacteria. Sixteen isolates (53.3%) were found to have moderate to high activity against\nfour gram-positive and four gram-negative bacteria. Since many isolates showed inhibitory activity against indicator bacteria, it is\nsuggestive that Bangladeshi soil could be an interesting source to explore for antibacterial secondary metabolites....
Chitin is highly insoluble N-acetylated polymer of β- (1, 4)-D-glucosamine. Chitosan is an acid soluble deacetylated form of chitin prepared from crab or shrimp shell. Both chitin and chitosan are present in most fungi and marine sources. The physicochemical characteristics of chitosan depend on the degree of deacetylation and also differ, based on the species and method of preparation. Chemical deacetylation is not necessary in the case of chitosan obtained from fungal source. Therefore the physicochemical properties and yield of chitosan isolated directly from fungi may be optimized by controlled fermentation. In this work fungal chitosan was prepared from Mucor hiemalis NCIM 873 without using strong alkaline solution normally used for deacetylation. Fungal chitosan was isolated at different time intervals and characterized by FT-IR and viscometry. The separated chitosan was also evaluated for its antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method using Ascorbic acid as a standard. The isolated Chitosan possessed degree of deacetylation in the range of 85-98%, viscosity between 14.12-15.94 (cP) and exhibited significant antioxidant activity in comparison to Ascorbic acid....
Background: The purpose of the study. Along with research on development of more efficient gene delivery\r\nsystems, it is necessary to search on stabilization processes to extend their active life span. Chitosan is a nontoxic,\r\nbiocompatible and available gene delivery carrier. The aim of this study was to assess the ability of this polymer to\r\npreserve transfection efficiency during spray-drying and a modified freeze-drying process in the presence of\r\ncommonly used excipients.\r\nMethod: Molecular weight of chitosan was reduced by a chemical reaction and achieved low molecular weight\r\nchitosan (LMWC) was complexed with pDNA. Obtained nanocomplex suspensions were diluted by solutions of\r\nlactose and leucine, and these formulations were spray dried or freeze dried using a modified technique. Size,\r\npolydispersity index, zeta potential, intensity of supercoiled DNA band on gel electrophoresis, and transfection\r\nefficiency of reconstituted nanocomplexes were compared with freshly prepared ones.\r\nResults and major conclusion: Size distribution profiles of both freeze dried, and 13 out of 16 spray-dried\r\nnanocomplexes remained identical to freshly prepared ones. LMWC protected up to 100% of supercoiled structure\r\nof pDNA in both processes, although DNA degradation was higher in spray-drying of the nanocomplexes prepared\r\nwith low N/P ratios. Both techniques preserved transfection efficiency similarly even in lower N/P ratios, where\r\nsupercoiled DNA content of spray dried formulations was lower than freeze-dried ones. Leucine did not show a\r\nsignificant effect on properties of the processed nanocomplexes. It can be concluded that LMWC can protect DNA\r\nstructure and transfection efficiency in both processes even in the presence of leucine....
DNA vaccines combining plasmids carrying the variola virus genes M1R, A30L, and F8L of intracellular virion surface membrane proteins as well as A36R and B7R of the extracellular virus envelope proteins under control of Rous sarcoma virus or cytomegalovirus promoters have been constructed. These DNA vaccines induced production of a high titers of vaccinia virus-neutralizing antibodies in mice similar to those elicited by the live vaccinia virus immunization. Mice vaccinated by created DNA vaccine were completely protected against a lethal (10 LD50) challenge with highly pathogenic ectromelia virus. These results suggest that such vaccine should be efficient in immunization of humans against smallpox....
Polycyclic aromatic hydrocarbons (PAHs) are natural and anthropogenic aromatic hydrocarbons with two or more fused benzene\r\nrings. Because of their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, PAHs are a\r\nsignificant environmental concern. Ligninolytic fungi, such as Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus\r\nostreatus, have the capacity of PAH degradation. The enzymes involved in the degradation of PAHs are ligninolytic and include\r\nlignin peroxidase, versatile peroxidase,Mn-peroxidase, and laccase. This paper summarizes the data available on PAH degradation\r\nby fungi belonging to different ecophysiological groups (white-rot and litter-decomposing fungi) under submerged cultivation\r\nand during mycoremediation of PAH-contaminated soils. The role of the ligninolytic enzymes of these fungi in PAH degradation\r\nis discussed....
The present study was carried out to investigate the effect of supplementation of co-encapsulated probiotic organism (Lactobacillus helveticus 194) along with 3% FOS using 2% sodium alginate as coating material in kulfi. The viability of Lactobacillus helveticus 194 incorporated into kulfi was monitored throughout the storage period of kulfi during 90 days storage period at 20°C. Control kulfi was made without supplementing probiotics in the kulfi, treatment I was supplemented with encapsulated Lactobacillus helveticus 194 (@ 8.75 log10 cfu/g), treatment II was supplemented with non encapsulated Lactobacillus helveticus 194 (@ 8.66 log10 cfu/g). The viable counts (log10 cfu/g) of Lactobacillus helveticus 194 in its nonencapsulated state in kulfi decreased to 6.81 log10 cfu/g by 90 days storage at 20°C. When the organism was encapsulated, the viable cell counts were reduced to 7.98 log10 cfu/g, respectively at the end of storage period. The results depict that microencapsulation helps to enhance the survival of probiotic bacteria in kulfi during frozen storage....
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