Impact of salinity changes on growth,oxygen consumption and expression pattern of selected candidate genes in the orange mud crab (Scylla olivacea)     

Md. Lifat Rahi  Tanzina Ferdusy  Shams Wali Ahmed  Md. Nuruzzaman Khan  Dania Aziz  Krishna R. Salin 《Aquaculture Research》2020,51(10):4290-4301

Change in environmental salinity level is a major limiting factor for the aquaculture productivity because it imposes severe stress on organisms that in turn retards growth. The orange mud crab (Scylla olivacea) is an important coastal aquaculture species (farming is practised in 10‰–20‰ salinity levels) in Bangladesh. The present study was conducted to investigate the changes in growth, O₂ consumption and mRNA expression levels of five selected genes in the orange mud crab (S. olivacea) exposed to three different experimental salinity levels (0‰, 10‰ and 20‰) for three months. Crabs reared at 10‰ and 20‰, showed significantly higher (p < .05) growth performance and expression of growth regulatory genes (Actin and α‐amylase). The highest levels (p < .05) of O₂ consumption and expression of ion regulatory genes (Na⁺‐K⁺‐ATPase, V‐type H⁺‐ATPase and Diuretic Hormone) were obtained at 0‰. Moderate levels of growth and expression of selected candidate genes were observed at 10‰ treatment while the highest levels of growth and gene expression were obtained at 20‰ (control salinity). Strong interactions were observed between growth performance and expression of growth genes (R² = 0.81–0.91), and rate of O₂ consumption and expression of ion regulatory genes (R² = 0.83–0.93), implying that the selected genes are important candidates for growth and ionic balance in S. olivacea. Growth performance was found to be very low at 0‰ initially, after 30 days crabs showed better growth performance at this salinity level. It is thus inferred that orange mud crab individuals might require 3–5 days for acclimation to salinity stress but it can take at least 30 days for acclimation to regular growth. Results indicate that with proper acclimation, the orange mud crab (Scylla olivacea) can be farmed at low salinity conditions and possibly in freshwater condition.  相似文献   

Preparation and characterization of jute fabrics reinforced urethane based thermoset composites: Effect of UV radiation     

Haydar U. Zaman  Avik Khan  Ruhul A. Khan  Tanzina Huq  Mubarak A. Khan  Md. Shahruzzaman  Md. Mushfequr Rahman  Md. Al-Mamun  P. Poddar 《Fibers and Polymers》2010,11(2):258-265

Jute fabrics reinforced thermoset composites were prepared with different formulations using urethane acrylate oligomer, methanol, and benzyl peroxide. Jute fabrics were soaked in the prepared formulations and fiber content in the composites was optimized with the extent of mechanical properties. Among all the resulting composites, 55 wt% jute content at oligomer:methanol:benzyl peroxide=75:24.5:0.5 (w/w/w) ratio showed best mechanical properties. The optimized jute fabrics were cured under UV radiation at different intensities and their mechanical properties were measured. Jute fabrics were treated with potassium permanganate (KMnO₄) solution of different concentrations (0.01, 0.02, 0.03, and 0.05 wt%) for different soaking times (1–5 min) before the composite fabrication. Optimized jute fabrics (jute fabrics treated with 0.02 wt% KMnO₄ for 2 min soaking time) were soaked in the optimized formulation and cured under UV radiation at different intensities and measured their mechanical properties. Scanning electron microscopic investigation showed that surface modification improves fiber/matrix adhesion. Water uptake and soil degradation test of the treated and untreated composite samples were also performed.  相似文献