Biology subjects

Islam, M. E.

Publications and source records attributed to Islam, M. E..

3 recordsLinked to original sources

bioRxiv2024

Isolation, Characterization, and Identification of Nitrogen Fixing Bacteria from Rhizosphere of Sonneratia apetala Collected from Sundarbans

Nitrogen is a crucial element for plant growth, driving vibrant greenery, photosynthesis, and overall vitality. This research focused on isolating, characterizing, and identifying nitrogen-fixing bacteria from the rhizosphere of Sonneratia apetala in the Sundarbans, Khulna, Bangladesh, with the goal of assessing their potential as biofertilizers. Despite the Sundarbans rich microbial diversity, less than 5-10% of species have been identified due to challenges in culturing, which has limited exploration of their applications. In this study, nitrogen-fixing bacteria were isolated using nitrogen-free media, including yeast extract mannitol agar(YEMA) and Burks media, followed by an ammonification test to select ammonia-producing bacteria. This process yielded ten nitrogen-fixing bacterial isolates capable of producing indole-3-acetic acid (IAA). Various biochemical tests, including oxidase, catalase, methyl red, indole, urease, citrate, triple sugar iron, and starch hydrolysis, were conducted. The isolates, designated AK1 to AK10, were identified as Rossellomorea sp., Clostridium sp., Achromobacter sp., Pseudomonas sp., Gluconacetobacter sp., Scytonema sp., Pseudomonas sp., Nesterenkonia sp., Gluconacetobacter sp., and Bacillus sp., respectively. Additionally, isolates AK1, AK3, AK4, and AK10 were confirmed through 16S rRNA sequencing. A pot test further revealed that isolate AK-1 significantly stimulated the growth and development of maize seedlings. Future studies are needed to examine the impact of these bacterial isolates on crop yield and seed quality, to better determine their suitability as biofertilizers.

microbiology↗

bioRxiv2024

Bioactivity Analysis of Secondary Metabolites from Actinomycetes' Isolated from Coastal Sediments

The rising threat of antibiotic resistance underscores the need for new antibiotics. Marine actinomycetes have emerged as promising sources of bioactive compounds. In this study, 22 isolates from marine sediments were morphologically identified, with nine confirmed as actinomycetes through 16S rRNA gene sequencing. Five strains- Streptomyces olivoverticillatus (T-2), Streptomyces cyaneus (T-4), Nocardiopsis synnemataformans (T-7), Streptomyces albogriseolus (T-8), and Streptomyces atrovirens (T-9)- exhibited significant antibacterial activity. Cultured in Starch Casein Broth, their metabolites were tested for antibacterial, antioxidant, anticoagulation, and anti-inflammatory activities. T-4 and T-8 demonstrated notable antimicrobial action, T-8 showing potent DPPH radical scavenging (372.09 {+/-} 11.05 {micro}g/mL). T-9 inhibited trypsin (IC50 435.12 {+/-} 15.88 {micro}g/mL) and had a prothrombin time of 12.08 {+/-} 1.46 minutes. T-8 enhanced RBC membrane stabilization (IC50 140.08 {+/-} 2.30 {micro}g/mL). These findings suggest that marine sediment-derived actinomycetes hold significant therapeutic potential and warrant further study.

microbiology↗

bioRxiv2022

Multisensory inputs control the regulation of time investment for mating by sexual experience in male Drosophila melanogaster

Males have finite resources to spend on reproduction. Thus, males rely on a time investment strategy to maximize their reproductive success. For example, male Drosophila melanogaster extends their mating duration when surrounded by conditions enriched with rivals. Here we report a novel form of behavioral plasticity whereby male fruit flies exhibit a shortened duration of mating when they are sexually experienced; we refer to this plasticity as shorter-mating-duration (SMD). SMD is a plastic behavior and requires sexually dimorphic taste neurons. We identified several neurons in the male foreleg and midleg that express specific sugar, pheromone and mechanosensory receptors. Using a cost-benefit model and behavioral experiments, we further show that SMD behavior exhibits adaptive behavioral plasticity in male flies. Thus, our study delineates the molecular and cellular basis of the sensory inputs required for SMD; this represents a plastic interval timing behavior that could serve as a model system to study how multisensory inputs converge to modify interval timing behavior for improved adaptation. ONE SENTENCE SUMMARYMale flies use information derived from their previous sexual experiences from multiple sensory inputs to optimize their investment in mating.

neuroscience↗