Meiobenthos of the Shelf Waters of West Coast of India With Special Reference to Free-Living Marine Nematodes

Department of Marine Biology, Microbiology and Biotechnology, Cochin University of Science and Technology

Broad-Band Gap Coupled Microstrip Antenna

A microstrip antenna with large bandwidth is developed using a parasitic technique . Compared to the available wide-baud antennas,the proposed antenna structure is very compact and gives a lessdistorted radiation pattern with frequency . An impedance bandwidth,eight times that of a conventional patch antenna of the same size, Isachieved. The concept of coupled microstrip line model Is extended fortheoretical interpretation of the impedance loci

Studies on Copepod Parasites on Elasmobranchs of Kerala Coast

The present study of the parasitic copepods gives the taxonomic description of thirty one species of parasites collected from various elasmobranch fishes of Kerala coast. Copepods parasitic on fishes include three sub orders, viz. poecilostomatoida, cyclopoida and siphonostomatoida. Parasitic copepods of elasmobranch fishes for the present study were collected from different fish landing centres of Kerala and by undertaking regular fishing trips. The collected parasites are identified to the species level and described. It is found that out of thirty one species, fifteen are new to science. They belong to the genera viz. Nothobomolochus Vervoot, 1962, Caligus Muller, 1785, Alebion, Kroyer, 1863, Gloipotes Steenstrup and Lutken, 1861, Pandarus Leach,1819, Perissopus Steenstrup and Lutken, 1861, Echthrogaleus Steenstrup and Lutken, 1861 and Kroyeria van Beneden, 1853. Fifteen new host records were reported. Two genera viz. Echthrogaleus and Entepherus were reported for first time from Indian waters. A new genus called Penicillus was erected. The general observations made during this study revealed certain interesting aspects of host-parasite relationship, host specificity, site specificity, adaptive modifications and geographical distribution.

Physiological and Genetic Diversity Studies on Regeneration of Santalum Album L.

S. album L. is the source of highly priced and fragrant heartwood which on steam distillation yields on an average 57 per cent oil of high perfumery value. Global demand for sandalwood is about 5000-6000 tons/year and that of oil is 100 tons/year. Heartwood of sandal is estimated to fetch up to Rs. 3.7 million/ton and wood oil Rs.70,000-100,000/ kg in the international market. Sandal heartwood prices have increased from Rs. 365/ton in 1900 to Rs. 6.5 lakhs/ton in 1999-2000 and to Rs. 37 lakhs/ton in 2007. Substantial decline in sandalwood production has occurred from 3176 tons/year during 1960-‘ 65 to 1500 tons/year in 1997-98, and to 500 tons/year in 2007.Depletion of sandal resources is attributed to several factors, both natural and anthropogenic. Low seed setting, poor seed germination, seedling mortality, lack of haustorial connection with host plant roots, recurrent annual fires in natural sandal forests, lopping of trees for fodder, excessive grazing, hacking, encroachments, seedling diseases and spread of sandal spike disease are the major problems facing sandal. While these factors hinder sandal regeneration in forest areas, the situation is accelerated by human activities of chronic overexploitation and illicit felling.Deterioration of natural sandal populations due to illicit felling, encroachments and diseases has an adverse effect on genetic diversity of the species. The loss of genetic diversity has aggravated during recent years due to extensive logging, changing landuse patterns and poor natural regeneration. The consequent genetic erosion is of serious concern affecting tree improvement programme in sandal. Conservation as well as mass propagation are the two strategies to be given due importance. To initiate any conservation programme, precise knowledge of the factors influencing regeneration and survival of the species is essential. Hence, the present study was undertaken with the objective of investigating the autotrophic and parasitic phase of sandal seedlings growth, the effects of shade on morphology, chlorophyll concentration and chlorophyll fluorescence of sandal seedlings, genetic diversity in sandal seed stands using ISSR markers, and the diversity of fungal isolates causing sandal seedling wilt using RAPD markers. All these factors directly influence regeneration and survival of sandal seedlings in natural forests and plantations.

Meiobenthos of Cochin backwaters in relation to macrobenthos and environmental parameters

Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology

Studies on the pathobiology of penaeid larvae and postlarvae

The thesis presents the results of the studies carried out on certain diseases encountered in the larvae and postlarvae of penaeid prawns raised in the hatcheries at Cochin, Madras and Mandapam Camp during September 1985- April 1988. In the preliminary survey carried out to understand the common diseases occurring in the penaeid larvae and postlarvae, seven cases of diseases and abnormalities were encountered. These included ciliate infestation, Nit_zschia closteriurn infestation, parasitic protozoaninfection, parasitic dinoflagellate infection, appendage necrosis, heteromorphic eye and abnormal eggs and deformed nauplii .The clinical signs, seasonal occurrence and incidence of each of the above cases were provided along with the information on environmental factors such as salinity, dissolved oxygen, temperature and pH of the rearing medium. The Thésis is presented in nine chapters. Chapter 1 surveys the literature on the diseases of penaeid larvae, postlarvae and adult prawns from India and abroad. This is followed by a chapter on the material and methods employed during the present investigation. In the third chapter, seven cases of diseases and abnormalities encountered in the larvae and postlarvae of Penaeus indicus and p. semisulcatus during the survey carried out in the hatcheries located at different centres of Central‘ Marine Fisheries Research Institute are presented and discussed .A bacterium responsible for appendage necrosis was isolated and its taxonomy was studied. It was Gram-negative, fermentative and motile rod. It was sensitive to vibriostatic compound, 0/129. This bacterium was found to be a new isolate of vibrio on the basis of its morphological, biological, physiological and biochemical characters and comparison of these characters with those described for other related vibrios. This new isolate of vibrio was deposited in vibro Referrence Laboratory, Centres for Disease Control, Georgia, U.S.A. and coded as vibrio sp. 2448-88.

Parasite distribution and histopathological studies on certain commercially important fishes of cochin area

In order to check the damage caused by the parasites, even though it is difficult in open waters, a proper understanding of the seasonal variation in the distribution of the parasite and other factors like age of the host, sex of the host, which affect distribution of parasite is a must. Although several workers have carried out investigations on the taxonomy of metazoan parasites of marine and brackish water Fishes of India, very little attempt is made to correlate such investigations with the host and the environment. In this thesis such an attempt is made by the researcher. In chapter one the literature related to the prevalence, mean intensity of infection, and histopathological changes caused by the metazoan parasites, in particular by helminths, copepods and isopods, was reviewed. Chapter two contains observations on the distribution pattern of parasites in relation to the season, sex, and size of the host. It was found that the prevalence rate of radiorynchus_indicus infecting the alimentary canal of Tachysurugs mgacuglatus, Ergasilus sp. infecting the gills of T maculatus, and Lernaeeniicus ramosus found on the body surface of Qeimgipteirfugs jagonicus was higher during monsoon season. But agarna malayi found in the opercular chamber and Ehilometra cephalus infecting the gonads of valamugil speiglari showed a higher prevalence rate during the postmonsoon season. This was discussed on the basis of the hydrographical characteristics prevailing in the study area during the three different seasons. It was also observed that the sex of the host did not influence significantly the distribution pattern of the parasites. The reasons for this were also discussed. Invariably, the size of the host was found to influence the parasite distribution pattern. It was observed that the prevalence rate showed an increase with increase in size of the fish. This was discussed on the basis of food habits of the host, along with other aspects An attempt was made in chapter three to study the histopathological effects of‘ the various parasites on their respective sites of attachments on host Fishes. It was found that except Rhadinorhyhchugs indicus, all other parasites produced damages of varying intensity, in the form of hypertrophy, rhyperplasia, haemorrhage, tissue disruption and ulcers. Interestingly, E. indicus, an acantho— cephalid with a powerful proboscis for attachment was found not to cause any serious damage to the intestine of the host Fish. All these aspects are included in the third and final chapter of the thesis.

Studies on The Copepod Fish Parasites of Kerala Coast

The present study of the parasitic copepods gives an account of the taxonomic description of seventy seven species of parasites collected from the food fishes of the Kerala coast. Out of the seventy seven species described, fourteen are new to science, two new records for the Indian waters and ten new host records. The males of Parapetalus longipinnatus Rangnekar and Lerna~thropus indicus Pillai were collected and described for the first time. The parasites described belong to the suborders Cyclopoida, Caligoida and Lernaeopodoida. The available description of many species of this locality is reviewed and supplemented with the help of the present detailed study. The general observations made during this study reveale certain interesting aspects of the host parasite relationship, host specificity, adaptive modification and geographical distribution. A brief discussion of these observations made is also presented.

Studies on the freshwater copepod fish parasites of Kerala

Studies on parasitic copepods from freshwater fishes are still in its infancy. In recent years, there- is a renewed enthusiasm in the study of freshwater fish parasites due to rapidly increasing aquaculture practices. The importance of diseases and their control assumes great significance because of the adverse impact of diseases on fish production and its economy. Copepods are one of the most harmful parasites of freshwater fishes. Reports on the damages caused by copepod parasites from different parts on the world are increasing alarmingly. But the information on parasitic copepods of freshwater fishes in India is quite meagre. Knowledge regarding this group of parasites, their Biology and pathology from Kerala. is lacking. The thesis consists of five chapters. The first chapter is a general introduction which deals with the review of literature on various aspects of parasitic copepods viz; systematics, life history, host-parasite relationship, ecology, pathogenicity, prophylaxis and control measures. Systematics of parasitic copepods of freshwater fishes collected during the present study forms the second chapter. The third chapter deals with the life cycle study of the new Lernaeid copepod, Lernaea osphronemi. The fourth chapter contains host-parasite relationship. ecology and treatment of ‘the’ new species of Lernaea On Osphronemus goramy. General observations and a summary of the entire work constitute the fifth chapter

Effect of industrial pollution on the benthic communities of a tropical estuary

Cochin backwaters, a tropical barbuilt estuary is well known for its prawn, molluscan and demersal fisheries. Also it formed the dumping area for sewage,235 retting of husks and discharge of effluents from industries located on either side of it. As a result the fishery is being gradually dwindled year after year due to the lowering of the water quality. The effect of industrial polution on the benthic community of this tropical estuary was worked out. An area extending over 21 km from the mouth of the estuary to upstream of industrial belt was selected. Temporal and spatial variations of 16 environmental parameters at 9 stations along the area were monitored monthly during 1981. Benthic fauna of these 9 stations consisted of amphipods , polychaetes, isopods, tanaidaceans, molluscs and other crustaceans (Decapods, Acetes, Alpheids, Balanus, insect larvae, chironomid larvae, cumacea and some fresh water forms ). Apart from these, sea anemone, flat worms, nematodes, sipunculoids, echinoderms and fishes were also encountered. 75 species belonging to 31 faunal groups were identified. Of these 31 groups, amphipods, polychaedes, isopods, tanaidaceans and molluscs were numerically abundant. Rest of the 26 groups (including 13 riverine forms) were found less significant due to their rare occurrence/low numerical abundance. Polychaetes and molluscs were the only major groups present at all the stations.

Ecobiology of helminth parasites of finfishes and shellfishes of Cochin waters with special reference to Digenetic trematodes

The great number of parasitic species of marine and brackishwater animals that have been described indicates that parasites play an important part in the ecology of the oceans and brackishwaters. Jnspite of their importance, marine and brackish parasites are probably the least known group of organisms. Considering the large number of marine and brackishwater hosts, especially in the tropics, it is no exaggeration to say that the description of marine and brackishwater parasites has hardly begun (Rohde, 1982). With this view in mind, an attempt has been made to study the ecobiology of the helminth parasites of finfishes and shellfishes of eochin waters with special reference to digenetic trematodes. The work is broadly divided into three chapters, Chapter 1 consists of a description of the study area, prevalence of infection and concurrent infections with helminth parasites, seasonal variation, host specificity> and zoogeography of digenetic trematodes; Chapter II deals with the systematics of digenetic trematodes; and Chapter III deals with studies on larval trematodes from molluscs and crustacea, adult from a molluscan host, life-cycle, biology and histopathology

Slot Line Fed Dipole Antenna For Wide Band Applications

A slot line fed planar dipole antenna with a parasitic strip for wide band applications is presented. The presented antenna offers a 2:1 VSWR bandwidth from 1.66 to 2.71 GHz covering the DCS/ PCS/UMTS and IEEE 802.11b/g bands with a gain better than 6.5 dBi. The uniplanar design, simple feeding, and high gain make it a versatile antenna for wireless applications

A Planar Compact Metamaterialinspired Broadband Antenna

An electrically small, broadband-modified, truncated ground metamaterial EZ antenna is presented. This, a modified EZ antenna system, achieves a larger bandwidth of the order of 650 MHz by adjusting the metamaterial-inspired meandered ground element fed by a top loaded monopole. The design is devoid of the large ground planes and the external parasitic elements used in conventional designs for achieving proper impedance matching characteristics. The antenna requires a small foot print of kg/5 3 kg/10, where kg is the guided wavelength corresponding to the lowest frequency of operation, when printed on a substrate of dielectric constant 4.4 and thickness 1.6 mm. The antenna offers a 2:1 VSWR bandwidth from 750 MHz to 1.4 GHz, which covers CDMA, GSM, and ISM bands

Low k thin films based on rf plasma-polymerized aniline

Thermally stable materials with low dielectric constant (k < 3.9) are being hotly pursued. They are essential as interlayer dielectrics/intermetal dielectrics in integrated circuit technology, which reduces parasitic capacitance and decreases the RC time constant. Most of the currently employed materials are based on silicon. Low k films based on organic polymers are supposed to be a viable alternative as they are easily processable and can be synthesized with simpler techniques. It is known that the employment of ac/rf plasma polymerization yields good quality organic thin films, which are homogenous, pinhole free and thermally stable. These polymer thin films are potential candidates for fabricating Schottky devices, storage batteries, LEDs, sensors, super capacitors and for EMI shielding. Recently, great efforts have been made in finding alternative methods to prepare low dielectric constant thin films in place of silicon-based materials. Polyaniline thin films were prepared by employing an rf plasma polymerization technique. Capacitance, dielectric loss, dielectric constant and ac conductivity were evaluated in the frequency range 100 Hz– 1 MHz. Capacitance and dielectric loss decrease with increase of frequency and increase with increase of temperature. This type of behaviour was found to be in good agreement with an existing model. The ac conductivity was calculated from the observed dielectric constant and is explained based on the Austin–Mott model for hopping conduction. These films exhibit low dielectric constant values, which are stable over a wide range of frequencies and are probable candidates for low k applications.