A note on the largest mackerel, Rastrelliger kanagurta caught off Karwar

The largest mackerel ever caught in this part of the coast measured 366 mm in total length and weighed 592 g. The morphological measurements (in mm) recorded are Total length 366; Standard length 311; Head length 84; Inter-orbital distance 29; Pre-orbital distance 27; Pre-ventral distance 103; Maximum height of body 85; Snout length 27; Eye diameter 15.5; Pectorial fin length 39; Anterior dorsal height 42; Posterior dorsal height 29; Ventral fin length 35

First record of Pig eye shark, Carcharhinus amboinensis (Muller & Henle, 1839) from Karnataka

The pig eye shark, Carcharhinus amboinensis is a requiem shark found in tropical waters between latitudes 260 N and 260 S, from the surface to 150m

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Not AvailableThe largest mackerel ever caught in this part of the coast measured 366 mm in total length and weighed 592 g. The morphological measurements (in mm) recorded are Total length 366; Standard length 311; Head length 84; Inter-orbital distance 29; Pre-orbital distance 27; Pre-ventral distance 103; Maximum height of body 85; Snout length 27; Eye diameter 15.5; Pectorial fin length 39; Anterior dorsal height 42; Posterior dorsal height 29; Ventral fin length 35.Not Availabl

Probiotic potential of lactobacillus strains isolated from sorghum-based traditional fermented food

Sorghum-based traditional fermented food was screened for potential probiotic lactic acid bacteria. The isolates were identified by biochemical, physiological and genetic methods. Species identification was done by 16s rRNA sequence analysis. The functional probiotic potential of the two Lactobacillus species viz., Lactobacillus plantarum (Lact. plantarum) and Lactobacillus pentosus (Lact. pentosus) was assessed by different standard parameters. The strains were tolerant to pH 2 for 1 h and resistant to methicillin, kanamycin, vancomycin and norfloxacin. Two (Lact. plantarum COORG-3 and Lact. pentosus COORG-8) out of eight isolates recorded the cell surface hydrophobicity to be 59.12 and 64.06 %, respectively. All the strains showed tolerance to artificial duodenum juice (pH 2) for 3 h, positive for bile salt hydrolase test and negative for haemolytic test. The neutralized cell-free supernatant of the strains Lact. pentosus COORG-4, Lact. plantarum COORG-1, Lact. plantarum COORG-7, Lact. pentosus COORG-8 and Lact. plantarum COORG-3 showed good antibiofilm activity. Lact. pentosus COORG-8 exhibited 74 % activity against Pseudomonas aeruginosa-MTCC 7903 and Lact. plantarum COORG-7 showed 68 % inhibition of biofilm against Klebsiella pneumonia MTCC 7407. Three (Lact. plantarum COORG-7, Lact. pentosus COORG-5 and Lact. pentosus COORG 8) out of eight isolates exhibited a good antimicrobial activity against Listeria monocytogenes and five isolates (Lact. pentosus COORG 2, Lact. plantarum COORG 1, Lact. plantarum COORG 4, Lact. pentosus COORG 3 and Lact. plantarum COORG 6) are active against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella pneumonia, Enterococcus faecalis. The study also evaluated the cholesterol lowering property of the Lactobacillus strains using hen egg yolk as the cholesterol source. The cholesterol in hen egg yolk was assimilated by 74.12 and 68.26 % by Lact. plantarum COORG 4 and Lact. pentosus COORG 7, respectively. The results of the present study suggest that the Lactobacillus strains isolated and characterized from sorghum-based fermented product may be used as probiotic strains for therapeutic applications

Azotobacter salinestris: A novel pesticide-degrading and prominent biocontrol PGPR bacteria

The species Azotobacter belongs to plant growth-promoting rhizobacteria (PGPR) group and are ubiquitous, aerobic, free-living and nitrogen (N2)-fixing bacteria commonly living in soil, water and sediments. Being the major group of soilborne bacteria, Azotobacter plays different beneficial roles by producing different types of secondary metabolites in the soil such as vitamins, amino acids, plant growth hormones, antifungal substances, hydrogen cyanide and siderophores. These secondary metabolites have direct influence on growth of shoot, root and seed germination of many agriculture crops. Among different species, Azotobacter salinestris is considered as efficient in N2 fixation (29.21 μg Nm/L/day), production of indole acetic acid (24.50 μg/mL), gibberellic acid (GA) (15.2 μg/25 mL) and phosphate-solubilizing activity (13.4 mm). Molecular and biochemical studies confirmed the identity of the isolates (A. salinestris KF470807). A. salinestris found tolerant to a highest NaCl concentration (6–8%), to maximum temperature (45 °C) and also to varied pH ranges (8–9). The isolate was tested for pesticide resistance and biodegradation studies and showed 100% biodegradation of pendimethalin and did not recorded pendimethalin residues. It was also studied for antifungal efficacy against phytopathogen Fusarium species and influence on growth parameters of cereals. A. salinestris helps to replace chemical fertilizer and restore the soil fertility and crop productivity for the sustainable agriculture

Diversity of toxic and phytopathogenic Fusarium species occurring on cereals grown in Karnataka state, India

A total of 198 cereal samples (53 maize, 54 sorghum, 37 paddy and 54 wheat) were collected from 11 districts of Karnataka to understand the percent infection (PI), relative density (RD) and their frequency (Fr) caused by Fusarium spp. All samples were screened by agar plating method using MGA 2.5 agar media and incubated at 25 ± 2 °C for 3–5 days. The study revealed the association of 10 different Fusarium species known trichothecene producers such as Fusarium acuminatum, F. avenaceum, F. crookwellense, F. culmorum, F. equiseti, F. graminearum, F. nivale, F. poae, F. sambucinum and F. sporotrichioides along with non-trichothecene producers like F. anthophilum, F. oxysporaum, F. proliferatum, F. semitectum, F. solani, and F. verticillioides. All the ten isolated potential trichothecene producing Fusarium species were analyzed for their ability to produce trichothecenes by using thin layer chromatography method. The highest infection of Fusarium spp. in maize was by F. verticillioides with PI of (2.95 %), with RD of (15.16 %) and highest Fr was by F. graminearum (79.24 %) and the lowest was F. avenasium with PI of (0.13 %). For sorghum maximum PI was by F. verticillioides (3.02 %), with F. graminearum having highest RD (14.39 %) and with F. verticillioides highest Fr. (72.22 %). In paddy highest PI was by F. verticillioides (3.21 %) and the least was by F. avenaceum (0.09 %). Similarly in wheat the highest PI was by F. verticillioides (2.76 %) while lowest was by F. avenaceum (0.10 %). The highest Fr was with F. graminearum (79.62 %) while the lowest was by F. avenaceum (3.70 %) and the highest RD was by F. graminearum (22.04 %) and lowest was by F. solani (0.72 %). The manually identified Fusarium spp. were further confirmed by PCR-based detection using ITS1 and ITS4 primers followed by sequencing of the PCR amplicons. PCR studies confirmed that all the tested fungal isolates belongs to Fusarium spp. with the amplicon size of 600 bp. Sequencing and the blast data from NCBI data base confirmed the sequence similarity of 99 % to the genus Fusarium and accession numbers were obtained. Chemotyping studies showed that the isolated Fusarium species are known to produce different types of trichothecenes. The study revealed the diversity in phytopathogenic Fusarium spp. in major cereal crops growing in different agro-climatic regions of Karnataka, India

PGP potential, abiotic stress tolerance and antifungal activity of <i>Azotobacter</i> strains isolated from paddy soils

322-331Azotobacter strains were isolated by serial dilution method and colonies were viscous, smooth, glistening, and brown to black colour on Jenson’s N-free agar. Morphological and biochemical tests showed characteristic features of Azotobacter. Further, molecular analyses revealed the presence of different Azotobacter species viz., <i style="mso-bidi-font-style: normal">A. armeniacus, A. chroococcum, A. salinestris, A. tropicalis and A. vinelandii. The isolates were tested for their ability of nitrogen fixation, indole acetic acid (IAA), gibberllic acid production and phosphate solubilization. Four isolates (GVT-1, GVT-2 KOP-11 and SND-4) were efficient in fixation of highest amount of N2 (29.21 μg NmL-1day-1), produced IAA (25.50 µg mL-1), gibberllic acid (17.25 μg 25 mL-1) and formed larger P solubilizing zone (13.4 mm). Some of the Azotobacter strains were produced siderophores, hydrogen cyanide and were positive for ammonia production with respect to antifungal activity of <i style="mso-bidi-font-style: normal">Azotobacter was tested with dual culture method and A. tropicalis inhibited the growth of Fusarium, Aspergillus and Alternaria species. <i style="mso-bidi-font-style: normal">Azotobacter isolates were tested against salt (0-10%), temperature (4-55ºC), pH (5.0-10) and insecticide chloropyrifos (0-3%) tolerance study. Among them, A. chroococcum was found tolerant to a maximum of 6% NaCl with a temperature of 35-45ºC and to a pH up to 8. All the 4 strains showed effective growth against 3% chloropyrifos concentration. The studies revealed that the Azotobacter strains not only produced plant growth promoting substances but are also tolerant to abiotic stresses such as temperature, pH and insecticides.</span

Pesticide tolerant Azotobacter isolates from paddy growing areas of Northern Karnataka, India

A total of 14 Azotobacter strains were isolated from different paddy cultivating soils with pH ranging from 6.5 to 9.5 by using serial dilution agar plate method. The strains were Gram negative, rod shaped, cyst forming and developed brown to black colored colonies, which were glistening, smooth, slimy on Ashby's agar plates. Biochemically they were positive for biochemical tests namely, indole production, citrate, catalase, carbohydrate fermentation and Voges-Proskauer test. Further, sequence analysis of PCR amplicons obtained from these cultures revealed the presence of five different Azotobacter species viz., Azotobacter vinelandii, Azotobacter salinestris, Azotobacter sp., Azotobacter nigricans subsp. nigricans and Azotobacter tropicalis. Phylogenetically these strains were grouped into two distinct clusters. These strains were tested for their ability to grow on a media containing four different pesticides such as pendimethalin, glyphosate, chloropyrifos and phorate, which are commonly used for the paddy. Out of 14 strains tested, 13 strains were able to grow on a media containing herbicides such as pendimethalin, glyphosate and insecticides like chloropyrifos and phorate. However, five Azotobacter strains were able to grow at higher concentration of 5 % pesticides, without affecting their growth rate. Further, the effect of pesticides on the indole acetic acid (IAA) production by Azotobacter strains was also estimated. Azotobacter-16 strain was found to produce 34.4 μg ml -l of IAA in a media supplemented with 1,000 mg of tryptophan and 5 % of pendimethalin. Present study reveals that species of Azotobacter are able to grow and survive in the presence of pesticides and no significant effects were observed on the metabolic activities of Azotobacter species

Characterization of phytotoxin producing <i>Alternaria </i> species isolatedfrom sesame leavesand their toxicity

36-43Sesame (Sesamum indicum L.), is an important oilseed crop in the tropics and subtropics, referred as “Queen of Oilseeds” owing to its high cooking quality and medicinal value. Sesame production, particularly in India, has been declining since last decade and ‘Leaf blight’ caused by Alternaria spp. is reported to cause yield loss up to 30-40%. Here, we investigated the fungal toxin produced by Alternaria and its pathogenicity. A total of 164 Alternaria strainswere isolated on potato dextrose agar media from the infected sesame leaves showing circular concentric rings with dark brown spots symptoms. All the isolates were screened for cultural and morphological characters. Colour of the fungus was grey to dark brown, formed smooth, raised, fluffy, and regular to irregular margins. Among 164 isolates, 43 isolates were moderately growing and 121 were fast in growth. The DNA of the isolate was amplified with ITS primers and sequence of BLAST results confirmed seven different species of Alternaria of NCBI database. Further, toxigenic potentiality of the isolates was tested with dilutions of culture filtrate (1:1 to 1:5) on sesame leaves. Among 164 isolates, 23 showed toxigenicity, varied from highly toxigenic to least toxigenic. Pathogenicity of the isolates showed that they were highly virulent to less virulent when tested by the detached leaf method. Based on the toxigenicity, the toxin was partially purified and brown coloured paste was recovered. Chemistry of the toxin was confirmed based on the IR, UV, NMR and mass spectra analyses, and it resembled the structure of alternariol mono methyl ether and altenuene which are mycotoxins in nature. Further, bioassay of toxin was carried out at different concentrations (50 to 2000 ppm) on seeds and seedlings of sesame. Maximum inhibition of seed germination of 81.1% was observed at 2000 ppm and the least was 6.67% at 50 ppm. With the increase in the concentration of toxin, the manifestation of the symptom was conspicuous and quick such as marginal, veinal necrosis, drooping and yellowing with lesion formation. From the present study, it is found that the species of Alternaria are responsible for the cause of blight disease symptoms and the toxicity of toxin produced by the pathogen was very high. The Alternaria toxin could inhibit the growth of the plant as well as seed germination rate