Sulfur accumulation in Vertisols due to continuous gypsum application for six years and its effect on yield and biochemical constituents of soybean (Glycine Max L. Merrill)

Application of S through inorganic sources is recommended to the crops in the cropping system in S deficient soils of India. However, transformations of S in the soil profile following continuous gypsum application are not known. The accumulation of S into different fractions due to application of a total of 180—540 kg S ha^—1 over a six‐year‐period in soybean — wheat cropping system and its effect on the yield and quality of soybean produce were investigated in a vertisol area. About 25—38% of the S added was retained in the 90 cm depth of profile. Significant changes in the total S content in soil layers were recorded wherein a total of 360 kg S ha^—1 or more S was applied. Maximum increase in total S content was recorded in upper layers. Soluble S accumulated more in the 30—75 cm depth; whereas, proportion of sorbed fraction of S increased with depth. Build up of S in the surface layer of the profile was mostly related to the increase in organic fraction. The S accumulation in lower layers of the profile was mostly due to increase in soluble and sorbed fractions of S. Such an increase of the S content in the soil caused an increase in seed yield, uptake of S as well as content of oil and S containing amino acids, cystine, and methionine in seed of soybean crop.     

Influence of cell volume changes on protein synthesis in isolated hepatocytes of air-breathing walking catfish (<Emphasis Type="Italic">Clarias batrachus</Emphasis>)

The present study aimed at determining the effect of cell volume changes on protein synthesis, measured as the incorporation of [³H]leucine into acid-precipitable protein, in isolated hepatocytes of air-breathing walking catfish (Clarias batrachus). The rate of protein synthesis, which was recorded to be 10.02 ± 0.10 (n = 25) nmoles mg⁻¹ cell protein h⁻¹ in isotonic incubation conditions, increased/decreased significantly by 18 and 48%, respectively, following hypo- (−80 mOsmol l⁻¹)/hypertonic (+80 mOsmol l⁻¹) incubation conditions (adjusted with NaCl), with an accompanying increase/decrease of hepatic cell volume by 12 and 20%, respectively. Similar cell volume-sensitive changes of protein synthesis were also observed when the anisotonicity of incubation medium was adjusted with mannitol. Increase of hepatic cell volume by 9%, due to addition of glutamine plus glycine (5 mM each) to the isotonic control incubation medium, led to a significant increase of protein synthesis by 14%. Decrease of hepatic cell volume by 15 and 18%, due to addition of dibutyl-cAMP and adenosine in isotonic control incubation medium, led to a significant decrease of protein synthesis by 30 and 34%, respectively. Thus, it appears that the increase/decrease of hepatic cell volume, caused either by changing the extracellular osmolarity or by the presence of amino acids or certain other metabolites, leads to increase/decrease of protein synthesis, respectively, and shows a direct correction (r = 0.99) between the hepatic cell volume and protein synthesis in walking catfish. These cell volume-sensitive changes of protein synthesis probably help this walking catfish in fine tuning the different metabolic pathways for better adaptation during cell volume changes and also to avoid the adverse affects of osmotic stress. This is the first report of cell volume-sensitive changes of protein synthesis in hepatic cells of any teleosts.     

Use of RAPD-PCR for genetic analysis of Nicobari fowl of Andamans

1. The present study was conducted to estimate genetic relatedness among Nicobari fowls (Brown, Black and White) and an exotic bird (White Leghorn) using random amplified polymorphic DNA (RAPD) polymorphism. 2. A total of 25 decamer primers were screened among all the breeds of which 24 primers amplified the genomic DNA, generating 2000 to 200 bp bands. Ten primers generated reproducible and distinct RAPD profiles and were used for further analysis. 3. A total of 94 bands were amplified and 30 polymorphic bands (32%) were produced. The number of polymorphic loci ranged from 1 to 5 with an average of 3.0. 4. Among the native breeds Brown Nicobari showed higher genetic similarity (0.85) than Black Nicobari (0.80) and White Nicobari fowl (0.82). 5. Brown Nicobari showed high genetic similarity with Black Nicobari (0.87 +/- 0.029); least similarity was between White Nicobari and White Leghorn (0.77 +/- 0.028). 6. The RAPD profile of all Nicobari fowls on amplification with the primers PBG5 and PBA12 showed specific bands of molecular size 1050 and 785 bp, respectively. 7. The native breeds showed the least genetic distance with each other while White Leghorn appeared to be most distant from the native breeds.     

Patterns of fish community composition and biodiversity in riverine fish sanctuaries in Bangladesh: Implications for hilsa shad conservation

Understanding biodiversity and community composition is a prerequisite to sustainable exploitation and conservation of fisheries. We assessed the spatial and seasonal patterns of fish community composition and biodiversity in seasonal no-take riverine sanctuaries in Bangladesh, which aim to conserve the anadromous hilsa shad (Tenualosa spp. and Hilsa keele). Fish samples were collected during monsoon, as well as pre- and postmonsoon, from five sites within two sanctuaries and one site in an open fishing area. Although total abundance was similar along the rivers, species richness was significantly higher at the open fishing site due to its connectivity to nearby habitats. The diversity apparently decreased in a downstream direction. Fish communities at two upstream sites were separated from other sites in multivariate space largely due to higher abundance of hilsa at downstream sites and presence of floodplain-oriented species at the two upstream sites. Short body length and high trophic level at all sites indicated that fish communities were overexploited. Our results also indicated that riverine hilsa sanctuaries in Bangladesh are rich in fish species diversity and support several threatened species designated by the International Union for Conservation of Nature (IUCN). Our study also suggested that since hilsa abundance shapes community patterns, it can therefore impact riverine ecosystem functioning in the sanctuary areas. The findings of this study can serve as an important baseline for future biodiversity assessment, conservation and impact assessment of conservation in rivers, and therefore help to establish multispecies ecosystem-based management of riverine fisheries around the world.     

Screening for drought tolerance in wheat genotypes by morphological and SSR markers

Journal of Crop Science and Biotechnology - Drought stress has become a significant abiotic stress for wheat in Bangladesh. This study aimed to explore drought tolerance in Bangladeshi wheat based...     

The competitiveness of the phytosociological attributes of the protected areas in Bangladesh with that in the other tropical countries

ABSTRACT

Many forest reserves in Bangladesh have been converted to protected areas (PAs) to conserve the forests resources from further depletion. This study has investigated if such initiatives have improved the state of biodiversity of these PAs amid tremendous anthropogenic pressure on forest resources. We have assessed the phytosociological attributes of the PAs in the country through a case study at Kaptai National Park (KNP) and compared the attributes with those of the adjacent areas and of the tropical forests across the world. We have identified 52 species belonging to 45 genera and 28 families. The most dominant species in KNP was Dipterocarpus spp. and the adjacent area was dominated by Tectona grandis. Unexpectedly, the Shannon-Wiener index of KNP has dropped down from 2.98 in 2000 to 0.90 in 2014. However, in terms of relative density, relative dominance, and relative frequency, KNP was better than the adjacent areas. In contrast, the mean Shannon-Wiener index in KNP (0.90) was smaller than that in the tropical countries (2.99). We recommend strengthening effective comanagement of PAs and enabling nonforestry income generation activities for the forest-dependent people so that the biodiversity of the PAs can be enriched while people’s livelihoods are ensured.     

Characterization of cellulase-producing bacteria from the digestive tract of tilapia, Oreochromis mossambica (Peters) and grass carp, Ctenopharyngodon idella (Valenciennes)

Isolation and characterization of cellulase‐producing aeorobic bacterial flora in the intestine of omnivorous tilapia (Oreochromis mossambica) and phytophagous Chinese grass carp (Ctenopharyngodon idella) have been carried out using selective carboxymethylcellulose‐agar (CMC‐agar) medium. The cellulolytic activity was measured both qualitatively and quantitatively. It was found that the ability of different strains in degrading cellulose varies within a wide range. Among the strains isolated from the gut of each test fish, TM1 and CI3 isolated from O. mossambica and C. idella, respectively exhibited maximum cellulolytic activity (67.02 and 35.8 U mL^?1 respectively). Pure cultures of these strains were selected for morphological, physiological and biochemical characterization. On the basis of these tests, the isolated strains were identified as Bacillus circulans (TM1) and Bacillus megaterium (CI3). Both the strains are rod‐shaped, motile and show better temperature (15–42°C) and pH (5–11) tolerance. The selected strains were further quantitatively assayed for amylase and protease activities. Maximum amylase and protease activities were exhibited by TM1 and CI3 respectively. Information generated from the present study might contribute towards better‐feed formulation incorporating plant ingredients.     

Development of a method to assess binding of astaxanthin to Atlantic salmon Salmo salar L. muscle proteins

Several methods were examined to characterize the binding between astaxanthin and salmon muscle protein(s) in order to provide tools for evaluation of the role of muscle proteins on astaxanthin retention in Atlantic salmon Salmo salar L. flesh. The methods included gel filtration chromatography, displacement of a hydrophobic probe and ultrafiltration. With gel filtration chromatography, aggregation of astaxanthin under the experimental conditions was a major problem for the separation of bound astaxanthin from free astaxanthin because the apparent molecular weight of aggregated astaxanthin or astaxanthin micelles was in the range of protein–astaxanthin complexes. Displacement of the fluorescent probe 8‐anilino‐1‐naphthalenesulphonate (ANS) was not effective as astaxanthin quenched the fluorophore so that displacement could not be observed. An ultrafiltration method was developed using 200‐mM sodium cholate for dispersion of astaxanthin aggregates. This allowed unbound astaxanthin to be separated from bound astaxanthin using a 30‐kDa filter. After salmon muscle proteins were solubilized in different fractions by sequential extraction using low ionic strength solutions, the astaxanthin binding of different fractions was assessed using the ultrafiltration method. The significant difference (P<0.05) observed in the astaxanthin binding of the various fractions suggests an application of this assay to detect differences in affinity of proteins for astaxanthin. The results also suggest that proteins other than actomyosin or actin can bind astaxanthin in Atlantic salmon flesh. This method can be used for the identification of astaxanthin‐binding proteins in salmon flesh and other tissues.     

Stimulation of ureogenesis in the perfused liver of an Indian air-breathing catfish, Clarias batrachus, infused with different concentrations of ammonium chloride

The pattern of changes of activity of the urea cycle enzymes and the rate of urea-N excretion were studied in the perfused liver of an Indian air-breathing ureogenic walking catfish, Clarias batrachus. The liver was perfused with different concentrations of NH₄Cl for a period of 60 min to determine the role of ammonia for stimulation of hepatic ureogenesis and the threshold level of ammonia loading needed to cause such stimulation. Both the urea-N excretion and the ammonia uptake by the perfused liver were found to be a saturable process. Ammonia accumulated significantly in the liver infused with 1.25 moles g liver ^–1 min^–1 of NH₄Cl, followed by a maximum accumulation of about 28.5 moles g wet wt^–1 with the infusion of 5.08 moles g liver^–1 min^–1. The Vmax of the urea-N excretion (0.47 mol g liver^–1 min^–1) was obtained with the addition of 5.08 moles g liver^–1 min^–1 of NH₄Cl. Both the tissue and the specific activity of the urea cycle enzymes, except ornithine transcarbamylase and arginase, were stimulated significantly with the infusion of either 1.25 or 5.08 moles g liver^–1 min^–1 of NH₄Cl. Maximum stimulation of tissue activity of carbamoyl phosphate synthetase (about 120%) was seen with the infusion of 5.08 mol g liver^–1 min^–1, and for argininosuccinate synthetase (about 135%), and argininosuccinate lyase (about 50%) with the infusion of 10.81 mol g liver^–1 min^–1 of NH₄Cl. Higher accumulation of ammonia of about 10–15 mol g wet wt^–1 from the physiological level in the perfused liver while infusing with NH₄Cl was suggested to be one of the major causes of stimulation of ureogenesis. The presence of such physiological adaptive strategy is probably necessary in this unique group of air-breathing walking catfish to survive under hyper-ammonia stress in their normal habitat or while living outside water or while burrowing inside mud.     

Functional ureogenesis and adaptation to ammonia metabolism in Indian freshwater air-breathing catfishes

The Indian freshwater air-breathing catfishes Heteropneustes fossilis and Clarias batrachus are hardy and capable of living in derelict water bodies and tolerating temporary water deprivation. Several studies have been made on their ureogenic adaptations, ureogenic metabolic machinery, and regulation under different physiological and environmental conditions. Both species are potentially ureogenic teleosts expressing the complete repertoire of ornithine-urea cycle (OUC) enzymes, not only in hepatic tissue but also in certain non-hepatic tissues. This review compiles the information available on the peculiarities of their ureogenic machinery and the induction of ureogenesis during adaptation to various stressful conditions such as exposure to high environmental ammonia, water deprivation, highly alkaline environment, etc. The biochemical profile and pattern of physiological adaptations, suggesting an intermediary status of these fishes in the evolution of ureotely in vertebrates, is discussed.