Novel physiological challenges in different environments can promote the evolution of divergent p... more Novel physiological challenges in different environments can promote the evolution of divergent phenotypes, either through plastic or genetic changes. Environmental salinity serves as a key barrier to the distribution of nearly all aquatic organisms, and species diversification is likely to be enabled by adaptation to alternative osmotic environments. The threespine stickleback (Gasterosteus aculeatus) is a euryhaline species with populations found both in marine and freshwater environments. It has evolved both highly plastic and locally adapted phenotypes due to salinity-derived selection, but the physiological and genetic basis of adaptation to salinity is not fully understood. We integrated comparative cellular morphology of the kidney, a key organ for osmoregulation, and candidate gene expression to explore the underpinnings of evolved variation in osmotic plasticity within two populations of sticklebacks from distinct salinity zones in the Baltic Sea: the high salinity Kattegat...
The present study was undertaken to investigate the prevalence of some selected heterotrophic bac... more The present study was undertaken to investigate the prevalence of some selected heterotrophic bacteria in one of the sewage lagoons and in the river Buriganga, which receives the sewage effluents from the sewage lagoons, with a view to evaluate the effect of sewage treatment. The heterotrophic plate count (HPC) ranged from 1.1 x 108 to 3.0 x 109 cfu/ml in sewage lagoon from January to December 2005. The HPC values ranged from 1.1 x 105 to 3.0 x 109 cfu/ml in the outfall of the sewage effluents and other sampling locations in the river Buriganga. The total and faecal coliform counts of the sewage lagoon and the discharge point in the river were always very high as >2.4 x 103 cfu/100 ml in all seasons as measured by the MPN method. Salmonellae were isolated occasionally, while vibrios were frequently isolated from all the sampling points from throughout the year. The MPN values of nitrifying bacteria were also estimated to compare with HPC values. Ammonium oxidizers ranged from 1.1...
Novel physiological challenges in different environments can promote the evolution of divergent p... more Novel physiological challenges in different environments can promote the evolution of divergent phenotypes, either through plastic or genetic changes. Environmental salinity serves as a key barrier to the distribution of nearly all aquatic organisms, and species diversification is likely to be enabled by adaptation to alternative osmotic environments. The threespine stickleback (Gasterosteus aculeatus) is a euryhaline species with populations found both in marine and freshwater environments. It has evolved both highly plastic and locally adapted phenotypes due to salinity-derived selection, but the physiological and genetic basis of adaptation to salinity is not fully understood. We integrated comparative cellular morphology of the kidney, a key organ for osmoregulation, and candidate gene expression to explore the underpinnings of evolved variation in osmotic plasticity within two populations of sticklebacks from distinct salinity zones in the Baltic Sea: the high salinity Kattegat...
The present study was undertaken to investigate the prevalence of some selected heterotrophic bac... more The present study was undertaken to investigate the prevalence of some selected heterotrophic bacteria in one of the sewage lagoons and in the river Buriganga, which receives the sewage effluents from the sewage lagoons, with a view to evaluate the effect of sewage treatment. The heterotrophic plate count (HPC) ranged from 1.1 x 108 to 3.0 x 109 cfu/ml in sewage lagoon from January to December 2005. The HPC values ranged from 1.1 x 105 to 3.0 x 109 cfu/ml in the outfall of the sewage effluents and other sampling locations in the river Buriganga. The total and faecal coliform counts of the sewage lagoon and the discharge point in the river were always very high as >2.4 x 103 cfu/100 ml in all seasons as measured by the MPN method. Salmonellae were isolated occasionally, while vibrios were frequently isolated from all the sampling points from throughout the year. The MPN values of nitrifying bacteria were also estimated to compare with HPC values. Ammonium oxidizers ranged from 1.1...
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Papers by Mehedi Hasan