NOPR Collection:

Colour preference and light sensitivity in trilobite larvae of mangrove horseshoe crab, Carcinoscopius rotundicauda (Latreille, 1802)

2014-03-01T00:00:00Z

Title: Colour preference and light sensitivity in trilobite larvae of mangrove horseshoe crab, Carcinoscopius rotundicauda (Latreille, 1802) Authors: Srijaya, TC; Pradeep, PJ; Hassan, A; Chatterji, A; Shaharom, F; Jeffs, Andrew Abstract: The trilobite larvae of C. rotundicauda were tested to determine their colour preference and light sensitivity until their first moulting (25 days post hatching) under laboratory conditions. Maximum congregation size of the trilobite larvae was found in the white zone respectively where (n= 12) followed by yellow (n= 8) and orange (n= 8), which showed the larval preference for lighter zones. Morisita’s index calculation showed a clumped/aggregated distribution (yellow, blue, orange and white) and uniform/hyper dispersed distribution (green, red and black) for various colours tested. Trilobite larvae showed least preference for brighter regions while tested in the experiment [black; (n=4) and red; (n=5)]. Experiments done to determine the light sensitivity of trilobite larvae showed that the larvae had more preference towards ultraviolet lights. The maximum congregation size of 38.8 and 40.7% of the larvae was encountered under ultraviolet light, when the light sources were kept horizontal and vertical, respectively. Overall, results suggested that the trilobite larvae of C. rotundicauda, preferred light source of shorter wavelengths (UV light) and colours of lighter zone (white, yellow, orange), which might be due to their adaptation to their natural habitat for predator avoidance, prey selection and water quality. Page(s): 281-290

Effect of Dactylogyrus catlaius (Jain 1961) infection in Labeo rohita (Hamilton 1822): Innate immune responses and expression profile of some immune related genes

2014-03-01T00:00:00Z

Title: Effect of Dactylogyrus catlaius (Jain 1961) infection in Labeo rohita (Hamilton 1822): Innate immune responses and expression profile of some immune related genes Authors: Dash, Pujarini; Kar, Banya; Mishra, Arpita; Sahoo, P K Abstract: The monogenean ectoparasite, Dactylogyrus sp. is a major pathogen in freshwater aquaculture. The immune responses in parasitized fish were analyzed by quantitation of innate immune factors (natural agglutinin level, haemolysin titre, antiprotease, lysozyme and myeloperoxidase activities) in serum and immune-relevant gene expression in gill and anterior kidney. The antiprotease activity and natural agglutinin level were found to be significantly higher and lysozyme activity was significantly lower in parasitized fish. Most of the genes viz., β2-microglobulin (β2M), major histocompatibility complex I (MHCI), MHCII, tumor necrosis factor α (TNFα) and toll-like receptor 22 (TLR22) in gill samples were significantly down-regulated in the experimental group. In the anterior kidney, the expression of superoxide dismutase and interleukin 1β (IL1β) were significantly up-regulated whereas a significant down regulation of MHCII and TNFα was also observed. The down-regulation of most of the genes viz, MHCI, β2M, MHCII, TLR22 and TNFα in infected gills indicated a well evolved mechanism in this parasite to escape the host immune response. The modulation of innate and adaptive immunity by this parasite can be further explored to understand host susceptibility. Page(s): 267-280

A new spectrophotometric method for quantification of potassium solubilized by bacterial cultures

2014-03-01T00:00:00Z

Title: A new spectrophotometric method for quantification of potassium solubilized by bacterial cultures Authors: Rajawat, Mahendra Vikram Singh; Singh, Surender; Saxena, Anil Kumar Abstract: A new spectrophotometric method was developed for the quantification of potassium in the culture broth supernatant of K-solubilizing bacteria. The standard curve of potassium with the new method, which is based on the measurement of cobalt, showed a regression coefficient (R²) of 0.998. The quantification values of potassium obtained with flame photometric method and the newly developed method showed a significant correlation (r) of 0.978. The new method depends on the precipitation of sodium cobaltinitrite with solubilized potassium in liquid medium as potassium sodium cobaltinitrite, which develops bluish green colour by the addition of conc. HCl. The intensity of developed colour can be recorded at 623 nm. This method involves less number of steps, is easy and time saving, and can be used for the reliable estimation of available potassium in culture broth supernatant of K-solubilizing bacteria Page(s): 261-266

Phenylpropanoid enzymes, phenolic polymers and metabolites as chemical defenses to infection of Pratylenchus coffeae in roots of resistant and susceptible bananas (Musa spp.)

2014-03-01T00:00:00Z

Title: Phenylpropanoid enzymes, phenolic polymers and metabolites as chemical defenses to infection of Pratylenchus coffeae in roots of resistant and susceptible bananas (Musa spp.) Authors: Vaganan, M Mayil; Ravi, I; Nandakumar, A; Sarumathi, S; Sundararaju, P; Mustaffa, M M Abstract: Activity differences of the first (phenylalanine ammonia lyase, PAL) and the last (cinnamyl alcohol dehydrogenase, CAD) enzymes of phenylpropanoid pathway in the roots of resistant (Yangambi Km5 and Anaikomban) and susceptible (Nendran and Robusta) banana cultivars caused by root lesion nematode, Pratylenchus coffeae, were investigated. Also, the accumulation of phenolics and deposition of lignin polymers in cell walls in relation to resistance of the banana cultivars to the nematode were analyzed. Compared to the susceptible cultivars, the resistant cultivars had constitutively significantly higher PAL activity and total soluble and cell wall-bound phenolics than in susceptible cultivars. The resistant cultivars responded strongly to the infection of the nematode by induction of several-time higher PAL and CAD enzymes activities, soluble and wall-bound phenolics and enrichment of lignin polymers in cell wall and these biochemical parameters reached maximum at 7^th day postinoculation. In addition, profiles of phenolic acid metabolites in roots of Yangambi Km5 and Nendran were analyzed by HPLC to ascertain the underlying biochemical mechanism of bananas resistance to the nematode. Identification and quantification of soluble and cell wall-bound phenolic acids showed six metabolites and only quantitative, no qualitative, differences occurred between the resistant and susceptible cvs. and between constitutive and induced contents. A very prominent increase of p-coumaric, ferulic and sinapic acids, which are precursors of monolignols of lignin, in resistant cv. was found. These constitutive and induced biochemical alterations are definitely the chemical defenses of resistant cvs. to the nematode infection. Page(s): 252-260