| Abstract: | The main objective of the work undertaken here was to develop an appropriate microbial technology to protect the larvae of M.rosenbergii in hatchery from vibriosis. This technology precisely is consisted of a rapid detection system of vibrios and effective antagonistic probiotics for the management of vibrios. The present work was undertaken with the realizations that to stabilize the production process of commercial hatcheries an appropriate, comprehensive and fool proof technology is required primarily for the rapid detection of Vibrio and subsequently for its management. Nine species of Vibrio have been found to be associated with larvae of M. rosenbergii in hatchery. Haemolytic assay of the Vibrio and Aeromonas on prawn blood agar showed that all isolates of V. alginolyticus and Aeromonas sp., from moribund, necrotized larve were haemolytic and the isolates of V.cholerae, V.splendidus II, V.proteolyticus and V.fluvialis from the larvae obtained from apparently healthy larval rearing systems were non-haemolytic. Hydrolytic enzymes such as lipase, chitinase and gelatinase were widespread amongst the Vibrio and Aeromonas isolates. Dominance of V.alginolyticus among the isolates from necrotic larvae and the failure in isolating them from rearing water strongly suggest that they infect larvae and multiply in the larval body and cause mortality in the hatchery. The observation suggested that the isolate V. alginolyticus was a pathogen to the larvae of M.rosenbergii. To sum up, through this work, nine species of Vibrio and genus Aeromonas associated with M.rosenbergii larval rearing systems could be isolated and segregated based on the haemolytic activity and the antibodies (PA bs) for use in diagnosis or epidemiological studies could be produced, based on a virulent culture of V.alginolyticus. This could possibly replace the conventional biochemical tests for identification. As prophylaxis to vibriosis, four isolates of Micrococcus spp. and an isolate of Pseudomonas sp. could be obtained which could possibly be used as antagonistic probiotics in the larval rearing system of M.rosenbergii. |
| URI: | http://dyuthi.cusat.ac.in/purl/88 |
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| Dyuthi-T0005.pdf | (2.250Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5196 |
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| Dyuthi T-2231.pdf | (9.816Mb) |
| Abstract: | White Spot Syndrome Virus (WSSV) is the most devastating disease affecting shrimp culture around the world. Though, considerable progress has been made in the detection and molecular characterization of WSSV in recent years, information pertaining to immune gene expression in shrimps with respect to WSSV infection remains limited. In this context, the present study was undertaken to understand the differential expression of antimicrobial peptide (AMP) genes in the haemocytes of Penaeus monodon in response to WSSV infection on a time-course basis employing semi-quantitative RT-PCR. The present work analyzes the expression profile of six AMP genes (ALF, crustin-1, crustin-2, crustin-3, penaeidin-3 and penaeidin-5), eight WSSV genes (DNA polymerase, endonuclease, immediate early gene, latency related gene, protein kinase, ribonucleotide reductase, thymidine kinase and VP28) and three control genes (18S rRNA, β-actin and ELF) in P. monodon in response to WSSV challenge. Penaeidins were found to be up-regulated during early hours of infection and crustin-3 during late period of infection. However, ALF was found to be up-regulated early to late period of WSSV infection. The present study suggests that AMPs viz. ALF and crustin-3 play an important role in antiviral defense in shrimps. WSSV gene transcripts were detected post-challenge day 1 itself and increased considerably day 5 onwards. Evaluation of the control genes confirmed ELF as the most reliable control gene followed by 18S rRNA and β-actin for gene expression studies in shrimps. This study indicated the role of AMPs in the protection of shrimps against viral infection and their possible control through the up-regulation of AMPs |
| Description: | Aquaculture 319 (2011) 11–17 |
| URI: | http://dyuthi.cusat.ac.in/purl/4049 |
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| Anti-lipopolysa ... ction by up-regulation.pdf | (922.2Kb) |
| Abstract: | Antimedian graphs are introduced as the graphs in which for every triple of vertices there exists a unique vertex x that maximizes the sum of the distances from x to the vertices of the triple. The Cartesian product of graphs is antimedian if and only if its factors are antimedian. It is proved that multiplying a non-antimedian vertex in an antimedian graph yields a larger antimedian graph. Thin even belts are introduced and proved to be antimedian. A characterization of antimedian trees is given that leads to a linear recognition algorithm. |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2009 |
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| Antimedian graphs.pdf | (151.5Kb) |
| Abstract: | Chitosan is a biocompatible and biodegradable natural polymer with established antimicrobial properties against specific microorganisms. The present study demonstrates its antibacterial activity against 48 isolates of Vibrio species from prawn larval rearing systems. The antibacterial activity had a positive correlation with the concentration of chitosan. This work opens up avenues for using chitosan as a prophylactic biopolymer for protecting prawn larvae from vibriosis. |
| Description: | Dis Aquat Org 67: 177–179, 2005 |
| URI: | http://dyuthi.cusat.ac.in/purl/4054 |
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| Antimicrobial a ... larval rearing systems.pdf | (111.1Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5411 |
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| Dyuthi T-2452.pdf | (12.22Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5442 |
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| Dyuthi T-2483.pdf | (15.99Mb) |
| Abstract: | Aquaculture farms, particularly in Southeast Asia are facing severe crisis due to increasing incidences of White Spot Syndrome Virus (WSSV). Actinomycetes have provided many important bioactive compounds of high prophylactic and therapeutic value and are continually being screened for new compounds. In this communication, the results of a study made to determine the effectiveness of marine actinomycetes against the white spot disease in penaeid shrimps are presented. Twenty-five isolates of actinomycetes were tested for their ability to reduce infection due to WSSV among cultured shrimps. When these actinomycetes were made available as feed additives to the post-larvae of the black tiger shrimp Penaeus monodon for two weeks and challenged with WSSV, the post challenge survival showed variations from 11 to 83%. However, six isolates have shown to be the most potential candidates for further study. |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2037 |
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| Antiviral property of marine actinomycetes.....pdf | (85.14Kb) |
| Abstract: | White spot syndrome virus (WSSV), the most contagious pathogen of cultured shrimp, causes mass mortality, leading to huge economic loss to the shrimp industry. The lack of effective therapeutic or prophylactic measures has aggravated the situation, necessitating the development of antiviral agents. With this objective, the antiviral activity in the aqueous extract of a mangrove plant Ceriops tagal in Penaeus monodon was evaluated. The Ceriops tagal aqueous extract (CTAE) was non-toxic to shrimps at 50 mg/ml when injected intramuscularly at a dosage of 10 lL/animal (0.5 mg/animal) and showed a protective effect against WSSV at 30 mg/ml when mixed with WSSV suspension at a 1:1 ratio. When the extract was administered along with the diet and the animals were challenged orally, there was a dose-dependent increase in survival, culminating in 100 % survival at a concentration of 500 mg/kg body weight/day. Neither hypertrophied nuclei nor the viral envelope protein VP28 could be demonstrated in surviving shrimps using histology and indirect immunofluorescence histochemistry (IIFH), respectively. To elucidate the mode of action, the temporal expression of WSSV genes and shrimp immune genes, including antimicrobial peptides, was attempted. None of the viral genes were found to be expressed in shrimps that were fed with the extract and challenged or in those that were administered CTAE-exposed WSSV. The overall results suggest that the aqueous extract from C. tagal can protect P. monodon from white spot syndrome virus infection. |
| Description: | Arch Virol (2012) 157:1665–1675 DOI 10.1007/s00705-012-1346-3 |
| URI: | http://dyuthi.cusat.ac.in/purl/4057 |
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| Anti–white spot ... shrimp Penaeus monodon.pdf | (846.9Kb) |
| Abstract: | Hindi |
| Description: | Department of hindi,Cochin University Of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4766 |
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| Dyuthi-T1863.pdf | (2.912Mb) |
| Description: | Dept.of Hindi,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2241 |
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| Dyuthi-T0567.pdf | (8.424Mb) |
| Abstract: | Hindi |
| Description: | DEPARTMENT OF HINDI, COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY |
| URI: | http://dyuthi.cusat.ac.in/purl/4832 |
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| Dyuthi-T1929.pdf | (4.819Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5311 |
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| Dyuthi T-2347.pdf | (8.226Mb) |
| Abstract: | The fresh water prawn, Macrobrachium rosenbergii, has proven potential for use as an aquaculture species (Hanson & Goodwin, 1997; Kurup, 1984). In India alone, culture of this species of prawn in low saline areas requires about 200 million seed per year (Kurup, 1984). In hatcheries poor survival rate has been associated with vibriosis at di#erent stages of the larval cycle. Members of the family Vibrionaceae associated with the larvae of M. rosenbergii were shown to be pathogenic under laboratory conditions (Bhat et al., 2000, in press). Vibrios have been associated with mortality of penaeid prawns by several workers (Aquacop, 1977; Hameed, 1993; Karunasagar et al., 1994). Two methods have been suggested to protect both the larvae and juveniles from vibriosis; one is the administration of bacterins prepared from pathogenic strains (Itami et al., 1989, 1991; Adams, 1991; Song & Sung, 1990; Sung et al., 1991) and the other is the utilization of yeast 1-3 and 1-6 glucans as immunostimulants for enhancing the non-specific defense system (Sung et al., 1994; Song et al., 1997). In the light of these observations it was hypothesised that bacterins and yeast glucans may also be e#ective in protecting the larvae of M. rosenbergii from vibriosis as has been achieved in the case of penaeids. To examine this hypothesis, the ability of bacterins and an extracellular glucan-producing yeast to increase the overall survival and metamorphosis of larvae in a hatchery, as well as to protect against an experimental challenge under laboratory conditions, was evaluated |
| Description: | Fish & Shellfish Immunology (2000) 10, 559–563 doi:10.1006/fsim.2000.0278 |
| URI: | http://dyuthi.cusat.ac.in/purl/4028 |
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| Application of ... nbergii from vibriosis.pdf | (83.96Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/728 |
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| V Vici,Application of bacterins...,march2000.PDF | (3.148Mb) |
| Abstract: | In India a study conducted by CIFE and CIBA (1997), concluded that shrimp farming does more good than harm and it is not eco-unfriendly (Krishnan and Birthal, 2002). Upsurge in coastal aquaculture activity induced by high profitability is reported to have caused adverse impacts on coastal ecosystems and social environments (Parthasarathy and Nirmala, 2000). The crustacean farming sector has received criticism for excessive use of formulated feed containing high protein, of which around 50% gets accumulated at the pond bottom as unconsumed (Avnimelech, 1999; Hari et al., 2004, 2006). The wasted feeds undergo the process of degradation and results in the release of toxic metabolites to the culture system. Reduction of protein in the feed, manipulation and utilisation of natural food in the culture system are the remedy for the above problems. But before reducing the feed protein, it should be confirmed that the feed with reduced protein is not affecting the growth and health of the cultured animal. In the present study, biofloc technology is identified as one of the innovative technologies for ensuring the ecological and environmental Sustainability and examines the compatibility of BFT for the sustainable aquaculture of giant prawn, M. rosenbergii. This thesis starts with a general introduction (Chapter-1), a brief review of the most relevant literature (Chapter-2), results of various experiments (Chapter-3-6), summary (Chapter-7) and recommendations and future research perspectives in the field of biofloc based aquaculture (Chapter – 8). The major objectives of this thesis are, to improve the ecological and economical sustainability of prawn farming by the applicationof BFT and to improve the nutrient utilisation in aquaculture systems. |
| Description: | School of Industrial Fisheries, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3263 |
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| Dyuthi-T1237.pdf | (4.761Mb) |
| Abstract: | The most common and conventional method for removing turbidity from water is by coagulating with alum or iron salts, and settling the precipitate in suitably designed clarifiers followed by filtration. But the sludge produced is bulky, difficult to dewater and accumulates in the dumping grounds causing environmental problems. Synthetic polymers such as polyacrylamide and polyethyleneoxide have been investigated for their ability to remove turbidity. They overcome many of the disadvantages of conventional methods, but are cost—effective only when rapid flocculation and reduction in sludge volume are demanded. Considering the aforementioned situation, it was felt that more easily available and eco-friendly materials must be developed for removing turbidity from water. The results of our studies in this direction are presented in this thesis. The thesis comprises of nine chapters, with a common bibliography at the end. Chapter 1 gives an introduction to the nature of turbidity and colour usually present in water. Chapter 2 discusses the nature and availability of the principal material used in these studies, namely chitosan. Chapters 3 to 8, which deal with the actual experimental work, are further subdivided into (a) introduction, (b) materials and methods, (c) results and discussion and (d) conclusions. Chapter 9 summarises the entire work so as to put the results and conclusions into proper perspective. |
| Description: | School of Environmental Studies, Cochin University of Science and Technology, |
| URI: | http://dyuthi.cusat.ac.in/purl/3404 |
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| Dyuthi-T1381.pdf | (6.212Mb) |
| Abstract: | The present study aimed at the utlisation of microbial organisms for the production of good quality chitin and chitosan. The three strains used for the study were Lactobacillus plantarum, Lactobacililus brevis and Bacillus subtilis. These strains were selected on the basis of their acid producing ability to reduce the pH of the fermenting substrates to prevent spoilage and thus caused demineralisation of the shell. Besides, the proteolytic enzymes in these strains acted on proteinaceous covering of shrimp and thus caused deprotenisation of shrimp shell waste. Thus the two processes involved in chitin production can be affected to certain extent using bacterial fermentation of shrimp shell.Optimization parameters like fermentation period, quantity of inoculum, type of sugar, concentration of sugar etc. for fermentation with three different strains were studied. For these, parameters like pH, Total titrable acidity (TTA), changes in sugar concentration, changes in microbial count, sensory changes etc. were studied.Fermentation study with Lactobacillus plantarum was continued with 20% w/v jaggery broth for 15 days. The inoculum prepared yislded a cell concentration of approximately 108 CFU/ml. In the present study, lactic acid and dilute hydrochloric acid were used for initial pH adjustment because; without adjusting the initial pH, it took more than 5 hours for the lactic acid bacteria to convert glucose to lactic acid and during this delay spoilage occurred due to putrefying enzymes active at neutral or higher pH. During the fermentation study, pH first decreased in correspondence with increase in TTA values. This showed a clear indication of acid production by the strain. This trend continued till their proteolytic activity showed an increasing trend. When the available sugar source started depleting, proteolytic activity also decreased and pH increased. This was clearly reflected in the sensory evaluation results. Lactic acid treated samples showed greater extent of demineralization and deprotenisation at the end of fermentation study than hydrochloric acid treated samples. It can be due to the effect of strong hydrochloric acid on the initial microbial count, which directly affects the fermentation process. At the end of fermentation, about 76.5% of ash was removed in lactic acid treated samples and 71.8% in hydrochloric acid treated samples; 72.8% of proteins in lactic acid treated samples and 70.6% in hydrochloric acid treated samples.The residual protein and ash in the fermented residue were reduced to permissible limit by treatment with 0.8N HCI and 1M NaOH. Characteristics of chitin like chitin content, ash content, protein content, % of N- acetylation etc. were studied. Quality characteristics like viscosity, degree of deacetylation and molecular weight of chitosan prepared were also compared. The chitosan samples prepared from lactic acid treated showed high viscosity than HCI treated samples. But degree of deacetylation is more in HCI treated samples than lactic acid treated ones. Characteristics of protein liquor obtained like its biogenic composition, amino acid composition, total volatile base nitrogen, alpha amino nitrogen etc. also were studied to find out its suitability as animal feed supplement.Optimization of fermentation parameters for Lactobacillus brevis fermentation study was also conducted and parameters were standardized. Then detailed fermentation study was done in 20%wlv jaggery broth for 17 days. Also the effect of two different acid treatments (mild HCI and lactic acid) used for initial pH adjustment on chitin production were also studied. In this study also trend of changes in pH. changes in sugar concentration ,microbial count changes were similar to Lactobacillus plantarum studies. At the end of fermentation, residual protein in the samples were only 32.48% in HCI treated samples and 31.85% in lactic acid treated samples. The residual ash content was about 33.68% in HCI treated ones and 32.52% in lactic acid treated ones. The fermented residue was converted to chitin with good characteristics by treatment with 1.2MNaOH and 1NHCI.Characteristics of chitin samples prepared were studied and extent of Nacetylation was about 84% in HCI treated chitin and 85%in lactic acid treated ones assessed from FTIR spectrum. Chitosan was prepared from these samples by usual chemical method and its extent of solubility, degree of deacetylation, viscosity and molecular weight etc were studied. The values of viscosity and molecular weight of the samples prepared were comparatively less than the chitosan prepared by Lactobacillus plantarum fermentation. Characteristics of protein liquor obtained were analyzed to determine its quality and is suitability as animal feed supplement.Another strain used for the study was Bacillus subtilis and fermentation was carried out in 20%w/v jaggery broth for 15 days. It was found that Bacillus subtilis was more efficient than other Lactobacillus species for deprotenisation and demineralization. This was mainly due to the difference in the proteolytic nature of the strains. About 84% of protein and 72% of ash were removed at the end of fermentation. Considering the statistical significance (P<O.05) in the extent of demineralization and deproteinisation, we have taken 0.8N HCI for the demineralization study and 0.6M NaOH for deprotenisation study. Properties of chitin and chitosan prepared were analyzed and studied. |
| URI: | http://dyuthi.cusat.ac.in/purl/2646 |
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| Dyuthi-T0706.pdf | (12.68Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5527 |
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| Dyuthi T-2570.pdf | (146.3Mb) |
| Abstract: | The present thesis report the results obtained from the studies carried out on the laser blow off plasma (LBO) from LiF-C (Lithium Fluoride with Carbon) thin film target, which is of particular importance in Tokamak plasma diagnostics. Keeping in view of its significance, plasma generated by the irradiation of thin film target by nanosecond laser pulses from an Nd:YAG laser over the thin film target has been characterized by fast photography using intensified CCD. In comparison to other diagnostic techniques, imaging studies provide better understanding of plasma geometry (size, shape, divergence etc) and structural formations inside the plume during different stages of expansion. |
| Description: | International School of Photonics,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2949 |
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| Dyuthi-T0940.pdf | (3.720Mb) |
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