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Among the tropical tuber crops, cassava (Manihot esculenta Crantz) deserves special attention as regards to its higher biological efficiency in terms of dry matter production which incidentally implies to the higher amount of nutrient extraction from the soil resulting in better response to the application of manures and fertilizers. Among the major nutrients, Potassium (K) is considered as the key nutrient for cassava owing to its influence both in tuber yield and tuber quality. The above facts as well as the availability of sufficient cassava genotypes in the germplasm collection of ICAR-CTCRI made us to initiate research work to screen cassava germplasm including the pre breeding lines. The objective being to identify K efficient genotypes which can yield well under limited availability of K so that the external application of K can be reduced. This paper describes the wide variation noticed during the pre evaluation of 83 elite genotypes which was done as a prelude in the screening and identification of K efficient genotypes. The characters studied were tuber yield, tuber characters, plant dry matter percentage, plant K content, tuber quality (starch, cyanogenic glucosides) attributes, physiological efficiency and plant biometric characters. The variation among the genotypes for the above traits was assessed by making some yardstick for classification which in turn helped in determining the percent distribution of genotypes in each category. The variation among the genotypes were further affirmed through principal component analysis, wherein the first five components explained more than 77% of variability and the cluster analysis performed grouped these genotypes into five clusters. The biplot showed the traits which are closely linked to the genotypes. The dendrogram constructed indicated similar genotypes to that of the clusters to the extent of more than 50% revealing the association of members with similar traits in clusters and dendrograms. The study helped in establishing the drastic variation among the genotypes along with identification of six genotypes viz., Aniyoor, 7 Sahya (2), 7 III E3-5, W-19, CR 43-8, 6-6 for further detailed experimentation to identify K efficient genotypes.

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A detailed pathological survey was carried out on the commercially important edible oyster, Crassostrea madrasensis (Preston), from two distinct coastal/brackish water ecosystems of south India. Samples were collected twice a year during wet and dry seasons from 2009 to 2012. Bacterial colonies in the form of prokaryotic inclusions, protozoans (Perkinsus beihaiensis, Nematopsis sp. and ciliates Sphenophrya sp. and Stegotricha sp.), metazoans (trematodes, turbellaria, cestodes and crustaceans) and shell parasites (Polydora spp. and Cliona spp.) along with various pathological conditions (digestive tubule atrophy, ceroid bodies, haemocytic infiltration, tissue necrosis and neoplastic disorders) were observed in C. madrasensis collected from two sites. Intensity, spatial and seasonal variations in infection prevalence and pathological effects on the host were studied. The protozoan parasite, P. beihaiensis; shell parasite, Polydora spp. and pathological condition, digestive gland atrophy were most prevalent in occurrence. High-intensity infections with P. beihaiensis, larval trematodes and Polydora spp. were found to cause significant impact on host physiology. All other parasites were observed with low mean prevalence and intensity. Karapad in Tuticorin bay, the site reported with marked pollution levels, exhibited higher number of parasitic taxa and high mean prevalence and intensity for pathological conditions.

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The present experiment was conducted to screen the α-amylase inhibitory activity of fucoidan extracted from Sargassum wightii collected at the coastal area of Mandapam, Tamil Nadu, India. Fucoidan was extracted from the sporophyll of S. Wightii by ethanol and CaCl2 precipitation method. The average yield was 1.8±0.16% and the extracted fucoidan was found to contain 53±0.52% of fucose and 36±0.60% of sulphate. Structural elucidation (FT-IR and NMR) and in vitro α-amylase activity of purified fucoidon were performed. Fucoidan at the concentration of 62.5, 125 and 250µg exhibited 24.81, 62.50 and 99.24% inhibition against α-amylase, respectively, in a dose dependent manner. Fucoidan from S. wightii also inhibits α-glucosidase which clearly indicates dual inhibitory activity of the compound. The IC50 value against α-amylase of fucoidan is found to be 103.83µg which is more effective than that of acarbose (16mg).

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The present study was conducted to screen the α-d-glucosidase inhibitory activity of fucoidan extracted from Sargassum wightii collected at Mandapam coastal area, Tamil Nadu, India. Fucoidan was extracted from the sporophyll of S. wightii using ethanol, acetone and CaCl2 precipitation. The average yield was 1.8 ± 0.16% and the extracted fucoidan was found to contain 53 ± 0.52% of fucose and 36 ± 0.60% of sulphate. FT-IR, NMR and in vitro α-d-glucosidase activity of purified fucoidan were performed. Fucoidan at the concentration of 31.25, 62.5, 125 and 250 µg exhibited 19, 31, 38 and 71% inhibition against α-d-glucosidase respectively in a dose dependent manner. The IC50 value against α-D-glucosidase of fucoidan is found to be 132.9 µg which is more effective than that of acarbose (1mg). The diverse biological activities of Fucoidan include anticancer, anti inflammatory and antimicrobial but the α-d-glucosidase inhibitory activity of native fucoidan from S. wightii for type 2 diabetes therapy is first of its kind.

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Protozoan parasites of the genus Perkinsus are considered important pathogens responsible for mass mortalities in many wild and farmed bivalve populations. The present study was initiated to screen populations of the Indian edible oyster Crassostrea madrasensis, a promising candidate for aquaculture along the Indian coasts, for the presence of Perkinsus spp. The study reports the presence of P. beihaiensis for the first time in C. madrasensis populations from the Indian subcontinent and south Asia. Samples collected from the east and west coasts of India were subjected to Ray's fluid thioglycollate medium (RFTM) culture and histology which indicated the presence of Perkinsus spp. PCR screening of the tissues using specific primers amplified the product specific to the genus Perkinsus. The taxonomic affinities of the parasites were determined by sequencing both internal transcribed spacer (ITS) and actin genes followed by basic local alignment search tool (BLAST) analysis. Analysis based on the ITS sequences showed 98 to 100% identity to Perkinsus spp. (P. beihaiensis and Brazilian Perkinsus sp.). The pairwise genetic distance values and phylogenetic analysis confirmed that 2 of the present samples belonged to the P. beihaiensis clade while the other 4 showed close affinities with the Brazilian Perkinsus sp. clade. The genetic divergence data, close affinity with the Brazilian Perkinsus sp., and co-existence with P. beihaiensis in the same host species in the same habitat show that the remaining 4 samples exhibit some degree of variation from P. beihaiensis. As expected, the sequencing of actin genes did not show any divergence among the samples studied. They probably could be intraspecific variants of P. beihaiensis having a separate lineage in the process of evolution.

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Alpinia officinarum is a rhizome belonging to the family zingeberaeceae. Hydro alcoholic extract by hot and cold maceration and methanol extract by percolation process Qualitative phytochemical analysis of extract of Alpinia officinarum rhizome showed a majority of the compound including tannins, alkaloids, flavonoids and saponins. Hydroalcoholic extract prepared by hot maceration process was found to contain more phenol and flavonol and it was measured as 50.1 mg/g and 54.02 mg/g, respectively. All the three extracts showed moderate to potent antimicrobial activity against the Bacillus cereus, Staphylococcus aureas, Pseudomonas auroginosa, Escherichia coli. None of the extracts showed antifungal activity against Aspergillus niger and Candida albicans. All the three extracts showed a concentration dependent radical scavenging activity by inhibiting diphenylpicrylhydrazyl free radical at the same time hydroalcoholic extract prepared by hot maceration process showed better reducing and total antioxidant activity.