Volume 9, Issue 4, 2009 October-December

Volume 9, No 4 Pages:
2009 October-December Articles: 5

Hazard effects of excess of zinc in diet

Zinc (Zn) is one of the trace minerals which is required for huge range of bodily functions. Since last two decades, Zn as micronutrient is being used indiscriminately in agricultural and husbandry practices and also in baby foods and multivitamin supplements since Zn is non-toxic and promotes body weight in the consumers. Thus, the concentration of Zn in some vegetables and animals food products and other dietary food items has been increased. So far, the effects of long term Zn overload in the body have not been reviewed. Consumption of excess Zn in diet for longer period of time may contribute obesity and related diseases in adolescence, copper (Cu)-deficiency related abnormalities in the adults and pregnant women. Excess Zn in diet makes diabetic patients more vulnerable due to increase in glycosylated haemoglobin level in the blood. The various aspects about harmful effect of excess Zn in diet is given in this communication.

Laboratory evaluation of the pathogenicity of three entomopathogenic nematodes against larvae of cabbage butterfly, Pieris brassicae Linnaeus (Lepidoptera: Pieridae)

The development of indigenously isolated entomopathogenic nematodes as biological control agents was investigated. The study involved three nematode species (Heterorhabditis indica, Steinernema thermophilum and S. glaseri) and their pathogenicity against larvae of cabbage butterfly, Pieris brassicae, under laboratory conditions. Nematodes of different concentrations (0, 10, 25, 50, 75, and 100 IJs/larva in 0.5 ml of distilled water) were applied against the insect pest using Petri dish assay. Progeny production of IJs was determined by the number of IJs produced per larva/pupa (within 20 days), following their exposure to IJs of EPN species at different concentrations. The data were analyzed statistically and the significance of the difference was determined by one way analysis of variance (ANOVA) and student’s t-test. LC50 and LT50 values were determined and estimated. Among the three species S. thermophilum caused larval mortality at 24 HAI (hours after inoculation) at 50 IJs/larva. However, at 48 HAI in addition to S. thermophilum, H. indica also revealed 100% mortality at 100 IJs/larva. In case of S. glaseri no mortality was observed at 24 HAI. The study thus concluded that both on the basis of mortality and LC50 value (30.2 IJs/larva at 48 HAI) S. thermophilum emerged as the most potent species. The progeny production by larvae of P. brassicae was noted to be highest only in case of H. indica. The production increased along the concentrations till the highest concentration for both H. indica and S. thermophilum but declined from 50 IJs/larva onwards in case of S. glaseri.

On the structure of Raillietina echinobothrida, the tapeworm of domestic fowl

The structure of Raillietina echinobothrida, the gastrointestinal tapeworm of the domestic fowl, Gallus domesticus, was studied using light and scanning electron microscopy. There are already reports on the fine structure of the parasite; however, due to the choice of procedure, many of the resultant information are inadequate, contradicting, and occasionally, erroneous. A slightly modified technique in the microscopic preparations employed in the present study such as the use of formaldehyde as a fixative and tetramethylsilane prior to air drying for SEM, and successive treatments with xylene and clove oil during histological processing provided far more superior methods, and definitely, better results. Unlike in other studies, the scolex was unambiguously a round, distended and bulbous anterior end of the body. The suckers were protruding oval structures, while the apical rostellum was distinctly an invaginated, depressed and hollow structure. The central spaces of both the suckers and rostellum were covered with smooth tegument, made up of ciliary microtriches. The microtriches on the proglottids were arranged in smooth cascades, all directed toward the posterior, and giving the topography of the tegument a uniform velvety appearance. The body cavity was mostly occupied by uteri containing fertilized eggs in a gravid proglottid; and by testes, ovaries, and vitellarium dispersed among the parenchyma in a mature proglottid. The parenchyma notably filled up the remaining pseudocoel of the body. The distinctive characteristics of R. echinobothrida were established to be the double layered rostellum of pick mattock-shaped hooks, a thick short neck and a single egg in each egg capsule.

Application of Mathieu potential to calculation of photocurrent from the surface of metals

Mathieu potential have been used for the photoemission calculations from surfaces of ferromagnetic material, Fe (iron), and semiconductor, PbSe (lead selenide). This approach gives a qualitative characterization of surface state photoemission by considering only the surface contribution from the existing bulk-band structure calculations. In this paper, we present the calculations of photocurrent from Fe and PbSe by using the Mathieu potential which defines the crystal potential. The derived initial wave function was used and variation of photocurrent only by those contribution from the surface region defined was calculated. Photocurrent was calculated for values of z0 = -2 a.u. and z0 = -8 a.u. As the width of the surface is 10 a.u. in both the cases, z0 = -2 a.u. is near the surface-vacuum interface and z0 = -8 a.u. is towards the surface-bulk interface. We found that at low photon energy range, the metal and the semiconductor under study showed similar trend in the behaviour of photocurrent at a region nearer to edge of the surface.

Traditional fishing methods in rivers and streams of Mizoram, north-east India

The Mizo tribes of north east India developed and practiced different types of fishing methods since time immemorial. Some methods can be considered as traditional as well as non-traditional since they are well known in some other parts of the country with some variation. This paper described fifteen traditional fishing methods. The study reveals that the people of Mizoram used locally available materials and apply indigenous ideas and skills (indigenous technical knowledge, ITK) for fishing. Various fishing techniques depend on various behavioural pattern and microhabitat type of fishes. Thirteen species of plants and plant products are used for fishing.