Gill epithelium of an angler catfish,Chaca chaca (Siluriformes,Chacidae): Enzyme and glycoprotein histochemistry

A series of histochemical techniques have been employed to localize alkaline phosphatase, acid phosphatase, non-specific esterase, catalase and peroxidase; and to visualize and characterize glycoprotein (GPs) moieties in the epithelium of gill arch, gill filaments and secondary lamellae of an angler catfish Chaca chaca. The epithelium of gill arch and gill filament shows strong alkaline phosphatase activity in the deeper layer epithelial cells; strong non-specific esterase activities in the outer layer epithelial cells; and weak acid phosphatase activity throughout the epithelium. The activity of these enzymes in the secondary lamellae is weak. The catalase and peroxidase show strong activities in the blood cells of the secondary lamellae. Various classes of GPs have been identified and characterized in the mucous secretions of the gill epithelium of C. chaca. These include—GPs with oxidizable vicinal diols, GPs with sialic acid residues without O-acyl substitution and GPs with O-sulphate esters. The functional significance of different enzymes in gill epithelium and the GPs in the mucus secreted on the surface has been discussed with the physiology of the gills in relation to the characteristic habit and habitat of the fish.     

Assessment of different methods of rice (Oryza sativa. L) cultivation affecting growth parameters, soil chemical, biological, and microbiological properties, water saving, and grain yield in rice–rice system

Field experiments were conducted at DRR farm located at ICRISAT, Patancheru, in sandy clay loam soils during four seasons, Kharif 2008, Rabi 2008–2009, Kharif 2009 and Rabi 2009–2010, to investigate growth parameters, water-saving potential, root characteristics, chemical, biological, and microbial properties of rhizosphere soil, and grain yield of rice (Oryza sativa L.) by comparing the plants grown with system of rice intensification (SRI) methods, with organic or organic + inorganic fertilization, against current recommended best management practices (BMP). All the growth parameters including plant height, effective tillers (10–45 %), panicle length, dry matter, root dry weight (24–57 %), and root volume (10–66 %) were found to be significantly higher with in SRI-organic + inorganic over BMP. With SRI-organic fertilization, growth parameters showed inconsistent results; however, root dry weight (3–77 %) and root volume (31–162 %) were found significantly superior compared to BMP. Grain yield was found significantly higher in SRI-organic + inorganic (12–23 and 4–35 % in the Kharif and Rabi seasons, respectively), while with SRI-organic management, yield was found higher (4–34 %) only in the Rabi seasons compared to BMP. An average of 31 and 37 % of irrigation water were saved during Kharif and Rabi seasons, respectively, with both SRI methods of rice cultivation compared to BMP. Further, total nitrogen, organic carbon%, soil dehydrogenase, microbial biomass carbon, total bacteria, fungi, and actinomycetes were found higher in the two SRI plots in comparison to BMP. It is concluded that SRI practices create favorable conditions for beneficial soil microbes to prosper, save irrigation water, and increase grain yield.     

Population structure,gene flow and genetic diversity analyses based on agro-morphological traits and microsatellite markers within cultivated and wild germplasms of okra [Abelmoschus esculentus (L.) Moench.]

Genetic Resources and Crop Evolution - Okra [Abelmoschus esculentus (L.) Monech.] is an annual herb of the family Malvaceae and has tremendous nutritional and industrial potential. However, the...     

Screening of Yardlong bean (Vigna unguiculata (L.) Walp.ssp. unguiculata cv.-gr. sesquipedalis) genotypes for seed,yield and disease resistance traits

Genetic Resources and Crop Evolution - Yardlong bean genotypes have wide variability in seed coat colours. This study sought to screen of yardlong bean genotypes based on seed coat colour,...     

Anticancer Activities of Plant Secondary Metabolites: Rice Callus Suspension Culture as a New Paradigm

Plant natural products including alkaloids,polyphenols,terpenoids and flavonoids have been reported to exert anticancer activity by targeting various metabolic pathways.The biological pathways regulated by plant products can serve as novel drug targets.Plant natural compounds or their derivatives used for cancer treatment and some novel plant-based compounds which are used in clinical trials were discussed.Callus suspension culture with secondary metabolites can provide a continuous source of plant pharmaceuticals without time and space limitations.Previous research has shown that rice callus suspension culture can kill>95%cancer cells with no significant effect on the growth of normal cells.The role of candidate genes and metabolites which are likely to be involved in the process and their potential to serve as anticancer and anti-inflammatory agents were discussed.Large scale production of plant callus suspension culture and its constituents can be achieved using elicitors which enhance specific secondary metabolites combined with bioprocess technology.     

Effect of Straw on Yield Components of Rice (Oryza sativa L.) Under Rice-Rice Cropping System

Field experiments were conducted at the Directorate of Rice Research experimental farm, ICRISAT campus, Patancheru, Hyderabad, during 1998–2000 for five consecutive seasons (three wet and two dry seasons) with five treatments [T1 – 100 % straw incorporation; T2 – 50 % straw incorporation; T3 – 100 % straw + green manure (GM) incorporation; T4 – 100 % straw burning and T5 – 100 % straw removal (control)] along with the recommended dose of fertilizers to evaluate the effect of different crop residue management (CRM) practices on yield components and yield of rice in rice–rice cropping sequence. The ammonium N measured at active tillering was higher in 100 % straw‐added plots over 50 % straw addition and straw removal with maximum values in the straw + GM‐incorporated plots. Among the yield components, tillers, panicles and spikelets were influenced from the second season of residue incorporation with significant increase in 100 % straw‐added treatments. The increase in tiller and panicle number could be attributed to the increased NH₄‐N in these treatments, which is evident from the significant correlation between tiller number and NH₄‐N (r = 0.82**) and panicle number and NH₄‐N (r = 0.87**). The influence of residue treatments on rice grain yield was observed from the third season onwards where incorporation of straw alone or in combination with GM and burning of straw significantly increased grain and straw yields. Grain yield showed significant positive correlation with the number of tillers (r = 0.74*–0.81**) and panicles (r = 0.74*–0.84**) in three treatments (T1, T3 andT4) where grain yields were significantly higher. The regression analysis showed that 57–66 % and 64–75 % of the variation in yield could be explained by tillers and panicles together in these three treatments during wet and dry seasons respectively. Thus, CRM practices such as addition of 100 % straw either alone or with GM and straw burning influenced the yield components (tillers, panicles and spikelets) positively and thereby increased rice grain yields.     

Seed inoculation with <Emphasis Type="Italic">Bacillus</Emphasis> spp. improves seedling vigour in oil-seed plant <Emphasis Type="Italic">Jatropha curcas</Emphasis> L.

Jatropha (Jatropha curcas L.) is a non-edible oil-seed plant with adaptability to marginal semi-arid lands and wastelands. The Indian Government is promoting jatropha to reduce dependence on the crude oil and to achieve energy independence by the year 2012, under the National Biodiesel Mission. Selected strains of Bacillus spp., either supplemented with or without chitin, were tested for their ability to promote growth of jatropha seedlings in pot culture studies. The strains supported growth of jatropha seedlings up to 42 days after sowing. Among all strains, Bacillus pumilus (IM-3) supplemented with chitin showed over all plant growth promotion effect resulting in enhanced shoot length (113%), dry shoot mass (360%), dry root mass (467%), dry total plant mass (346%), leaf area (256%), and chlorophyll content (74%) over control. Treating seeds with strain IM-3 without chitin resulted in enhanced dry shoot mass (473%), dry total plant mass (407%), and chlorophyll content (82%). However, Bacillus polymyxa (KRU-22) with chitin supported maximum root length (143%). Either strain IM-3 alone or in combination with other promising strains could be promoted further for enhanced initial seedling growth of jatropha.     

Xylanase-producing microflora in Eastern Ghats of Andhra Pradesh,India

We screened soil samples collected from underneath shrubs and/or large trees at different locations in the Eastern Ghats of Andhra Pradesh for xylanase-producing microorganisms. Xylose-utilizing bacteria were numerically dominant in soils of most locations whereas xylose-and xylan-utilizing actinobacteria were minor components. Xylan-utilizing fungi constituted a major share of total microbial populations in soil samples collected at half of the sites, whereas xylan-utilizing bacteria were predominant at other sampling locations. Some of the isolates of fungi exhibited xylanase activity with a range of400–4000 U/ml, indicating great potential for their uses in paper, pulping and bioethanol industries for producing value-added products.     

Characterization of Longidorus helveticus (Nematoda: Longidoridae) from the Czech Republic

Longidorus helveticus was found at two out of 285 sampling sites for the first time in the Czech Republic. Females, males and juvenile stages were analyzed morphologically and morphometrically. The morphological identification of samples was verified by polymerase chain reaction using a species specific primer. Four markers of ribosomal DNA (18S, ITS1, ITS2, D2-D3 expansion segments of 28S rRNA) and two markers of mitochondrial DNA (cox1 and nad4) were sequenced and analyzed and compared with published gene sequences of other populations of L. helveticus. The partial mitochondrial cytochrome c-oxidase subunit 1 gene and partial nicotinamide dehydrogenase subunits 4 gene showed relatively high genetic variation within the species compared with ribosomal DNA markers.     

Purification, characterization and evaluation of insecticidal activity of trypsin inhibitor from Albizia lebbeck seeds

A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.1 M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion exchange chromatography on DEAE-Sephadex A50. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60°C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 μM. The inhibitor was found to be susceptible to varying concentrations of reducing agents like DTT and 2-mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth of Pieris brassicae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.