Seed set and seedling variation in greater yam (Dioscorea alata L.)

Summary A high degree of fruit and seed set was obtained in Dioscorea alata L. by hand pollination. The sexual progeny was studied in comparison with the clonal plants. In general, the seedlings were poor in growth vigour, flowering and tuber production but the variations observed in the different characters were unprecedented, indicating scope for efficacious genetic improvement in this vegetatively propagated crop.     

The inversion of sensory processing by feedback pathways: a model of visual cognitive functions

The mammalian visual system has a hierarchic structure with extensive reciprocal connections. A model is proposed in which the feedback pathways serve to modify afferent sensory stimuli in ways that enhance and complete sensory input patterns, suppress irrelevant features, and generate quasi-sensory patterns when afferent stimulation is weak or absent. Such inversion of sensory coding and feature extraction can be achieved by optimization processes in which scalar responses derived from high-level neural analyzers are used as cost functions to modify the filter properties of more peripheral sensory relays. An optimization algorithm, Alopex, which is used in the model, is readily implemented with known neural circuitry. The functioning of the system is investigated by computer simulations.     

Isolation and characterization of a 20 kD prolamin from kodo millet (Paspalum scrobiculatum) (L.): Homology with other millets and cereals

The homologus 20 kD prolamin from kodo millet and other minor millets viz. barnyard, little and foxtail millets, were purified using preparative gel electrophoresis and reversed phase high performance liquid chromatography (RP-HPLC). The amino acid composition of the purified 20 kD prolamin protein from different minor millets revealed higher content of glutamic acid, alanine, leucine and serine and lower quantity of lysine and methionine. They contain 55 to 58 percent of non-polar amino acids which make them more hydrophobic than other protein fractions. The total number of amino acid residues per polypeptide chain ranged from 152 to 155 based on theoretical calculation. Peptide mapping of the 20 kD prolamin hydrolyzed with trypsin gave fewer cleavage products than expected. The antigenic relationships among these minor millets and cereals viz. wheat, maize, rice, sorghum, finger millet and pearl millet were studied using the antibody raised against the 20 kD prolamin. Cross reactivity was seen in all the minor millets at the 20 kD region. But in barnyard and little millets lower molecular weight polypeptides also cross reacted with the antibody. Immunoblotting studies revealed that the prolamins from other cereals and millets are related to the 20 kD prolamin of kodo millet. Rice was the only common cereal that did not cross react immunologically with the antibody raised against 20 kD prolamin of kodo millet.     

Homologies between prolamins of different minor millets

Minor millets, viz. Barnyard millet, Proso millet, Little millet, Foxtail millet and Kodo millet, one variety in each grown in Tamil Nadu Agricultural University (TNAU), Coimbatore, Tamil Nadu were selected for the study. The protein contents of the selected decorticated millets were found to be 11.0, 12.3, 12.9, 10.5 and 10.6% respectively. Fractionation of these proteins revealed that prolamin forms major storage protein in Foxtail millet whereas, glutelin forms major storage protein in all the other millets. The extractability was studied using different solvents, viz. isopropyl alcohol, t-butyl alcohol and ethyl alcohol with varying concentration of 2-mercapto ethanol. Electrophoretic pattern of the extracted prolamins from these millets were compared and found that a protein band at the molecular weight range of 20 kD was found homologous in all except Proso millet. The extractability of the 20kD protein in 90% isopropyl alcohol showed its strong hydrophobic nature.     

Isolation,Characterization and Quantification of Tricin and Flavonolignans in the Medicinal Rice Njavara (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.), as Compared to Staple Varieties

Njavara is an important medicinal rice variety of Kerala, India, widely used in Ayurveda as a ‘health food’ and in the treatment of rheumatoid arthritis, paralysis, neurodegenerative diseases and in rejuvenation therapy. Phytochemical investigations and spectroscopic studies of the diethyl ether fraction of methanolic extract of Njavara Black (NB) rice bran gave three important compounds namely, tricin and two rare flavonolignans- tricin 4′-O-(erythro-β-guaiacylglyceryl) ether and tricin 4′-O-(threo-β-guaiacylglyceryl) ether. The EC₅₀ values of these compounds in DPPH system were 90.39, 352.04 and 208.1 μg/ml, respectively. Quantification of the compounds by HPLC in NB and staple, non-medicinal rice varieties Sujatha (SJ) and Palakkadan Matta (PM) showed that tricin is present 39.64 and 16.12 fold higher in NB, compared to SJ and PM, respectively. This is the first report on the occurrence of tricin at significantly higher levels in Njavara and occurrence of the two flavonolignans in Oryza sativa species. Of the three compounds, tricin and the threo- form of flavonolignan showed anti-inflammatory effect of >65% after 5 h, at 2 mg/kg, in carrageenan-induced, paw edema experiments in rats. The results of the study corroborate with the preferential use of Njavara in indigenous medicine, over staple varieties.     

Microencapsulation of Fish Oil Using Fish Protein Hydrolysate,Maltodextrin, and Gum Arabic: Effect on Structural and Oxidative Stability

ABSTRACT

Microencapsulated fish oil was prepared by spray drying using fish protein hydrolysate, sodium caseinate, maltodextrin, and gum Arabic as wall material. Fish protein hydrolysate was prepared from pink perch meat, and its physical and functional properties were studied. Microencapsulates prepared with a combination of sodium caseinate, maltodextrin, and gum Arabic were kept as control. The encapsulation efficiency and oil release behavior of microencapsulates was evaluated. Surface morphology and thermal properties of microencapsulates were determined by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) analysis, respectively. Fourier-transformed infrared spectroscopy analysis indicated that the spectral pattern of microencapsulates showed a similar structural pattern with a minor band shift for both control and fish protein hydrolysate containing microencapsulates. Oxidative stability of fish oil microencapsulates indicated that the sample stored under was 4°C was more stable than microencapsulates stored under 60°C and 28 ± 2°C temperature conditions. Moreover, microencapsulates containing fish protein hydrolysate had a lower thiobarbituric acid value. Results suggest that the incorporation of fish protein hydrolysate along with other wall material could improve the oxidative stability of microcapsules during storage.     

Collection of plant genetic resources from Andaman and Nicobar Islands

The Andaman and Nicobar (A&N) group of islands is immensely rich in plant biodiversity. Andaman’s native tribes are hunter-gatherers, sustaining on wild or marine food and practically do not have any cultivation. Diversity in cultivated crops is presently maintained in home gardens by settlers from the mainland and other adjoining countries. The National Bureau of Plant Genetic Resources (NBPGR) through explorations either alone or in association with CARI or with other ICAR institutes has collected 1234 accessions in 48 exploration and collection missions. Variability was collected in rice, cowpea, black gram, green gram, okra, Chinese spinach, ash gourd, taro, cucumber, pumpkin, bottle gourd, ridge gourd, bitter gourd, chilli, greater yam and coconut. Indigenous landraces are absent. The in situ conservation of the wild relatives of crops is well taken care of by a large number of protected forest reserves.     

Gamma radiation susceptibility of strains of Tribolium castaneum (Herbst) resistant and susceptible to fenvalerate

Gamma radiation susceptibility of adults of the fenvalerateresistant strain of Tribolium castaneum (Herbst) (Coleoptera : Tenebrionidae) was studied under laboratory conditions. Selection for resistance to fenvalerate in adult beetles was carried out up to the sixth generation. In each generation of selection, adults of the fenvalerateresistant strain were evaluated for susceptibility to gamma radiation and compared with their fenvalerate-susceptible counterparts. Susceptibility to 60Co gamma radiation was evaluated on the basis of dosage-mortality (LD) and time-mortality (LT) responses. We found the LD values 50 50 50 for the fenvalerate-resistant and-susceptible strains to be 89.16 and 97.46 Gy respectively, showing no significant difference in susceptibility to gamma radiation. LT values were 7.58 and 17.20 days for the 50 fenvalerate-resistant and-susceptible strains respectively, showing that mortality in the resistant strain occurred markedly earlier than in the susceptible strain.     

Dietary protein requirement of giant mud crab Scylla serrata juveniles fed iso-energetic formulated diets having graded protein levels

The protein requirement of juvenile mud crab Scylla serrata (body weight=0.25±0.051 g, carapace width=9.3±0.04 mm) fed with different iso-energetic, iso-lipidic diets with graded protein levels (15–55% crude protein at 5% intervals) was determined. The feeding trial was conducted for a period of 63 days to determine the minimum and optimum protein requirement of juvenile S. serrata . The crabs fed with 15% and 20% dietary protein levels showed 100% and 12.5% of mortalities respectively. The mortalities observed in the above treatments were associated with the prolonged intermoult duration (46 and 32 days respectively). All other treatments recorded 100% survival. The best growth performance as well as the nutrient turn-over was recorded in crabs fed with 45% crude protein in the diet. Second-order polynomial regression of specific growth rate (SGR) as well as body protein gain vs. dietary protein levels suggested that 46.9–47.03% dietary protein is required for the best growth response and protein deposition in juvenile S. serrata . An extrapolation of 'SGR' and 'daily protein gain' upon the 'dietary protein level' axis ( Y =0) showed that 14.7–16.2% dietary protein is necessary for the minimum maintenance metabolism.