Abundance of sulphur‐oxidizing bacteria in coastal aquaculture using soxB gene analyses

Molecular techniques based on sequencing of metagenomic clone libraries provide an insight into the diversity of microbial populations. Using nucleic acid‐based methods, the diversity of soxB genes was examined to detect and characterize sulphur‐oxidizing bacteria in Indian coastal aquaculture environments. Gene‐specific degenerate primers were used to amplify various fragments (710, 753, 483–503, 280 and 239 bp) of soxB genes. Metagenomic clone libraries were constructed for 753, 483–503 and 239 bp fragments of soxB genes. The abundance of soxB revealed the presence of sulphur‐oxidizing organisms. Amino acids in parts of the soxB‐encoded proteins were aligned to known conserved amino acid residues. The level of conservation ranged from 23% to 30%. A phylogenetic tree constructed from aligned amino acid sequences of SoxB revealed different clusters associated with the branches of phototrophic α‐ and γ‐proteobacteria. In general, soxB is widespread among the various phylogenetic groups, although this does not necessarily mean that the organism can use sulphur compounds. Our results suggest that the chemolithoautotrophy based on sulphur oxidation in coastal aquaculture is primarily sustained by the presence of sulphur oxidizers, which involve the soxB gene. This study aids identification of the phylogenetic characteristics related to sulphur bioremediation in poorly characterized coastal aquaculture environments.     

Effect of dietary protein and lipid levels on growth,nutrient utilization and whole‐body composition of blue gourami,Trichogaster trichopterus fingerlings

Nine semi‐purified diets were prepared with three levels each of protein (300, 350 and 400 g/kg) and lipid (60, 80 and 100 g/kg) and fed ad libitum to Trichogaster trichopterus fingerlings (0.61 ± 0.03 g) in triplicate groups (10 fish/replicate) for 90 days to determine optimum dietary protein and lipid levels. Twenty‐seven flow‐through fibre‐reinforced plastic tanks (200 l capacity each with 100 l of water) were used for rearing the fish. The dietary protein, lipid and their interactions had significant effects (p < 0.05) on weight gain, feed conversion ratio, specific growth rate, nutrient retention and digestibility, but not on hepato‐ and viscerosomatic indexes (p > 0.05). Dietary protein and the interaction of protein with lipid had significant effect (p < 0.05) on whole‐body dry matter, lipid and energy contents, but not on protein and ash contents (p > 0.05). But, the dietary lipid had significant (p < 0.05) effect on whole‐body dry matter, protein, lipid and energy contents except the ash contents (p > 0.05). For each level of dietary protein, the increase in dietary lipid resulted significant increase (p < 0.05) in whole‐body lipid contents without affecting the protein and ash contents (p > 0.05). Based on better growth and dietary performances, the optimum dietary protein and lipid levels of blue gourami fingerling are 350 and 80 g/kg diet respectively.     

Coinoculation of bioinoculants improve Acacia auriculiformis seedling growth and quality in a tropical Alfisol soil

We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.     

Introgression of bacterial leaf blight resistance and aroma genes using functional marker-assisted selection in rice (Oryza sativa L.)

Functional markers reduce the risk of false selection in marker-assisted selection (MAS), and recombination between the molecular marker and the gene of interest. The present study was conducted with the objective of combining the important basmati quality traits with resistance to bacterial leaf blight (BLB) by a combination of phenotypic selection and MAS. Screening of 29 recombinants for BLB resistant genes along with aroma (fgr) gene was performed using a suite of different markers. Twenty genotypes were found in homozygous condition for Xa21 and xa13 genes. Restriction digestion analysis with BsrI, gave nine resistant recombinants. Out of nine resistant recombinants, seven were in homozygous and two were in heterozygous conditions. Recombinants viz., IRS 5441-2-21, IRS 5441-2-79, IRS 5441-2-81, IRS 5441-2-85 and IRS 5441-2-91 possessed all the three BLB resistance genes and fgr in the homozygous condition. Recombinants with enhanced resistance to BLB, basmati quality and desirable agronomic traits were identified. This germplasm can be directly developed into commercial varieties or used as immediate potential donors of BLB resistance in basmati breeding programs.     

Leaf nitrogen status as influenced by varying levels of nitrogen application and its relationship with yield in ‘Kew’ pineapple

A field trial conducted to determine the response of pineapple cultivar ‘Kew’ to varying levels of N with constant P and K under both irrigated and rainfed conditions, was utilised for studying the relationships between base and leaf N content of “D” leaf (first fully developed leaf) and yields. The soil was high in available N and medium in available P and K. Samplings were done in the 5th, 8th and 11th months. Application of N was clearly reflected in both base and leaf N content at all stages. Differences in base N and leaf N due to irrigation or no irrigation were observed only in the 8th-month sampling. Critical levels of base and leaf N were worked out utilising the statistical procedure of Cates and Nelson (1971).     

Synthesis and characterization of water-soluble phthalocyanine Copper(II) complex and its coloration on acrylic fibers

Herein, we report the synthesis and dyeing property of cationic copper phthalocyanine (cationic CuPc). The synthesized cationic CuPc was characterized using UV-Vis spectra and it showed good solubility in aqueous solution over a wide pH range. The dyeing of cationic CuPc was successfully employed onto acrylic fiber. The dyeing of acrylic fiber using cationic CuPc was achieved using conventional method. The effects of five important variables such as liquor ratio, dye concentration, dyeing time, temperature and pH were examined on the color strength (K/S) of dyed acrylic fiber. The maximum color strength was obtained at lower liquor ratio (100:1), higher dye concentration (6 %), longer dyeing time (60 min), 120 °C and alkaline condition (pH 11).     

Cadmium alters the reproductive endocrine disruption and enhancement of growth in the early and adult stages of Oreochromis mossambicus

Heavy metal cadmium (Cd) traces are able to promote growth (growth promoter) and induce early maturation in Oreochromis mossambicus fries of both sexes, whereas, in the adults, they degenerate the gonads and their function. The gathered data on length–weight relation, gonado-somatic index, hepato-somatic index, egg numbers and reproductive hormones such as gonadotropins (GtH-I and GtH-II) and gonadial hormones such as progesterone, testosterone and estradiol levels all prove Cd as an endocrine disruptor.