Despite the medicinal values and economic importance, honey is also a source of osmophilic fermentative yeasts. So, it can be utilized for the isolation of local fermentative yeast. Here, 1ml honey was inoculated in yeast extract peptone dextrose (YPD) broth containing 4% dextrose. After overnight incubation, the broth was streaked on an YPD agar plate to purify yeast colonies. In this study, total eight strains were isolated from seven physio-chemically defined florally diversified honey samples of Bangladesh. Microscopic morphology, plasmid profile, growth pattern and fermentative capacity of these isolates were determined. Under light microscope, these yeasts had one of three distinct shapes: ovoid, spherical, or cylindrical. The cytoplasm in young, actively reproducing cells occupied most of the interior and looked homogeneous. Two plasmids of around 3kb and 2.1 kb were common in these strains except for one. While compared with Baker’s yeast, these strains showed faster growth. Five of them were attributed to high fermentative potency. Yeast 2 showed the highest fermentative potency yielding 33.48% (v/v) ethanol. We suggest that these strains have potentialities for efficient bioethanol production to meet the increasing demand of biofuel.

Antibiotics are the secondary metabolites produced by bacteria and fungi to defend themselves from other pathogens. These secondary metabolites are being produced and used as a drug to cure different diseases. However, antibiotic resistance is a common problem that demands an urgent need to discover new antibiotics routinely. Several approaches have been performed to develop novel and potent antibiotics from natural sources against pathogenic bacteria. Among the different sources soil has been considered as the potent natural source of obtaining bacteria with the ability to produce novel antibiotics. The present work has been focused on the isolation of antibiotic producing bacteria from the soil samples collected from waste dumpsite. Among the 5 microbial isolates, 2 were shown to have inhibitory activities against Escherichia coli and Salmonella paratyphi. Morphological and biochemical tests revealed that both strains were Bacillus species with some differences in cultural characteristics. Molecular identification was performed by sequencing of the amplified 16S rRNA PCR products. The result showed that the two microbes were Bacillus subtilis and Bacillus cereus with 98% and 97% similarity score, respectively. This study suggests that Bacillus species have the potential to produce antibiotics against a broad spectrum of microbial growth and will be helpful in improving these strains for better production.

Microbial hydrolytic enzymes, especially cellulase and protease, are widely used in industrial processes due to their low cost, large productivity, chemical stability, environmental protection, plasticity and vast availability. But existing cellulase and protease enzymes are not capable enough to fulfill the industrial demands due to the lack of adapting operational conditions. So, the present study focused on extracting enzymes from microbial sources to overcome the problems. 260 isolated bacterial strains from different areas of Sylhet, Bangladesh, were screened for their cellulolytic and proteolytic activities using carboxymethylcellulose (CMC) and skim milk agar respectively. Among them 6 cellulolytic and 15 proteolytic bacteria were initially identified. Based on the capability to degrade CMC and skim milk, strain S32 was found to be the most potential among the isolates. Biochemical tests and molecular identification revealed that S32 is a strain of Aeromonas hydrophila and was later named as Aeromonas hydrophila ASM-S32. Maximum cellulase production by the strain A. hydrophila ASM-S32 was obtained after 18 hours (h) of incubation in a fermentation medium with an initial pH of 6.5 at 37°C and that was 4-fold higher as compared to unoptimized conditions. Maximum cellulase activity was observed at 60°C with a pH of 6.5 in presence of Ca2+ metal ion. In case of protease, optimum enzyme production was observed after 24 h of incubation with an initial pH of 8.5 at 37°C and protease production was increased by 1.2-folds when optimized conditions were used. Maximum protease activity resulted from pH 6.0, at 70°C and in presence of Cu2+ ion.

Various factors like plant growth regulator combinations, explant type and explant age were examined for establishing a convenient protocol for high frequency plant regeneration of Brassica napus. Cotyledon and hypocotyl explants of B. napus cv. BARI sarisha-8 were cultured on Murashige and Skoog (MS) medium fortified by different strengths of 6-Benzylaminopurine (BA), 2,4-Dichlorophenoxy Acetic Acid (2,4-D) and a-Napthalene Acetic Acid (NAA) to determine the suitable callus induction and shoot regeneration media. MS medium supplemented with 0.5 mg/L NAA and 3.0 mg/L BA was the best combination as regeneration medium because of showing highest frequency for both callus (80% for cotyledon and 53.33% for hypocotyl explants) and shoot initiation (73.33% for cotyledon and 40% for hypocotyl explants). Four days old cotyledon explants showed the highest (73.33%) frequency of shoot regeneration and highest shoot number to each explant (3.13) when 3-7 days old cotyledon cultured. Among the four tested genotypes of B. napus, BARI sarisha-8 showed the highest shoot regeneration frequency (73.33%) with maximum shoot number to each explant (3.13) while the lowest frequency of shoot regeneration was found in BINA sarisha-4 (46.66%) with minimum shoot number per explant (1.66). The ideal rooting medium was MS media comprised with 0.1 mg/L NAA that offered the maximum frequency (100%) of rooting. The regenerated plantlets were shifted to pot soil, acclimatized and grown until maturity in natural conditions. All plants were fertile and morphologically identical with the source plants. This protocol for high frequency regeneration of B. napus could be used for genetic transformation experiments.

Profilin is an actin monomer-binding protein that controls the dynamic turnover of actin filaments and is ubiquitously present in different organisms ranging from prokaryotes to higher eukaryotes. Maize (Zea mays) profilin-4 isoform is a pollen-specific protein. Birch profilin isoform is a known allergen but maize profilin is yet to be characterized. In this study, we investigated the properties of maize profilin-4 isoform’s allergenicity. To this end, we first analyzed profilin-4 isoform’s physicochemical properties, including molecular weight (~14kD), theoretical pI (4.63), and amino acids composition; and found that it might have allergenic potency. Then we tested the potential B cell epitope candidates using different immune-informatics tools housed at IEDB analysis resource. For the B cell epitope prediction, potential antigenic sites on the protein surface were predicted by both propensity scale and machine learning method followed by their mapping of 3D structure prediction. Our findings suggest that profilin-4 isoform is a potential allergen and can induce allergic responses.

The aim of this study was to explore phytochemical profiling, antioxidant and antibacterial activity of four medicinal plants including Catharanthus roseus, Aegle marmelos, Moringa oleifera, and Ageratum conyzoids grown in Sylhet district, Bangladesh. In this study, total 11 phytochemicals were screened from methanol extract of four medicinal plants, wherein flavonoid, tannin, sterol, phenol were present in all four medicinal plants. In vitro, antioxidant activity of these medicinal plants extract was investigated by DPPH-radical scavenging assay. The Aegle marmelos exhibited the highest antioxidant activity followed by Moringa oleifera, Ageratum conyzoids, and Catharanthus roseus extract. Methanolic extracts of same medicinal plants were subjected to a test of their antibacterial activities against Staphylococcus aureus, Escherichia coli, Klebsiella sp., Pseudomonas sp .and Salmonella sp. by agar disc diffusion method. The highest antibacterial potential was observed in the extract of Aegle marmelos against Salmonella sp. followed by Catharanthus roseus against Pseudomonas sp .with zone of inhibition of 18.67 mm, 15.0 mm, respectively. This study confirmed the efficacy of some native medicinal plants extract as potential source of phytochemicals, along with natural antioxidant and antimicrobials, which provide new possibilities to employing them against disease causing test organisms.

Arsenic (As) is a naturally occurring ubiquitous environmental toxicant. It has been reported that spirulina has protective effects against As toxicity. In the present study, we compared the prophylactic effects of spirulina [laboratory grown agro-based spirulina (Ab-Sp) and market spirulina (M-Sp)] against the histopathological changes in liver induced by inorganic arsenic (iAs) in male rats. Three doses (1.0g, 1.5g and 2.0g/kg feed) of both the Ab-Sp and M-Sp with feed and 3.0mg NaAsO2/kg body weight (BW) in drinking water were given simultaneously to six groups (T4, T5, T6, T7, T8 and T9) of rats daily for 90 days. Same dose of NaAsO2 (3.0mg/kg; T1) and highest dose (2.0g/kg) of each of Ab-Sp (T2) and M-Sp (T3) were given individually to other 3 groups keeping the rest one as control (T0) with normal feed and water. As feeding resulted in a variety of histopathological changes in liver, including congestion in the central veins, hemorrhage in the hepatic lobules and lobular tissues, higher numbers of hypertrophic hepatocytes with hypertrophic nucleus, hepatocytes with visible chromatin in the nucleus and vacuolated hepatocytes. The Ab-Sp treatment successfully improved all the histopathological conditions. In contrast, the M-Sp improved the conditions by combating all the histopathological conditions including vacuolated hepatocytes, erosions and hemorrhages in the liver. Taken together, the spirulina was found as an effective agent in prevention of the histopathological changes while we first clarified that Ab-Sp had better result than the M-Sp and finally, 2.0g Ab-Sp/kg feed was found as the best dose.