Reproductive biology of the commercial sea cucumber <Emphasis Type="Italic">Holothuria spinifera</Emphasis> (Echinodermata: Holothuroidea) from Tuticorin,Tamil Nadu,India

The annual reproductive cycle of the commercial sea cucumber Holothuria spinifera was studied in Tuticorin, Tamil Nadu, India, from September 2000 to October 2001, by macroscopic and microscopic examination of gonad tubule, gonad index and histology of gametogenic stages, to determine the spawning pattern. The gonad consists of long tubules with uniform development. It does not confirm the progressive tubule recruitment model described for other holothurians. The maximum percentage of mature animals, gonad and fecundity indices, tubule length and diameter, with the observations on gonad histology, ascertained that H. spinifera had the peak gametogenic activity during September and October 2001 followed by a prolonged spawning period from November 2000–March 2001.     

Anthelmintic activity of Butea monosperma

The methanol extract of Butea monosperma seeds, tested in vitro, showed significant anthelmintic activity.     

Role of cathepsins B and D in proteolysis of yolk in the catfish Clarias gariepinus

Fish Physiology and Biochemistry - Yolk processing pathways vary in the oocytes of benthophil and pelagophil teleosts. The present study investigated the yolk processing pattern in the oocytes of...     

Effects of temperature, salinity and pH on larval growth, survival and development of the sea cucumber Holothuria spinifera Theel

For large-scale seed production of sea cucumbers through a hatchery system, it is imperative to know the effects of environmental parameters on larval rearing. Auricularia larvae (48 h post-fertilization) were obtained from induced spawning of Holothuria spinifera and used in experiments to ascertain the effects of temperature, salinity and pH on the growth and survivorship of the larvae. The larvae were reared for 12 days at temperatures of 20, 25, 28 and 32 °C; salinities of 15, 20, 25, 30, 35 and 40 ppt; and pH of 6.5, 7.0, 7.5, 7.8, 8.0, 8.5 and 9.0. The highest survivorship and growth rate and fastest development of auricularia indicated that water temperature of 28–32 °C, salinity of 35 ppt and pH of 7.8 were the most suitable conditions for rearing larvae of H. spinifera.     

Biscrolling nanotube sheets and functional guests into yarns

Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 weight percent of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50-nanometer-thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, lithium-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and titanium dioxide for photocatalysis.     

Deltamethrin and cypermethrin resistance status of Rhipicephalus (Boophilus) microplus collected from six agro-climatic regions of India

A cross sectional study was conducted to assess the prevalence of synthetic pyrethroids (SP) resistance in Rhipicephalus (Boophilus) microplus in India. Twenty-seven areas located in six agro-climatic regions were selected for the collection of engorged ticks using two stage stratified sampling procedure. Adult immersion test (AIT) and larval packet test (LPT) were optimized using laboratory reared susceptible line of R.(B.) microplus (IVRI-I) for determination of 95% lethal concentration (LC(95)) of deltamethrin (29.6 ppm in AIT and 35.5 ppm in LPT) and cypermethrin (349.1 ppm in AIT and 350.7 ppm in LPT). The AIT with a discriminating dose (2 × LC(95)) was used to detect deltamethrin and cypermethrin resistance in the field isolates of R.(B.) microplus. On the basis of the data generated on three variables viz., mortality, egg masses and reproductive index, the resistance level was categorized as I, II, III and IV. The overall prevalence of SP-resistant R.(B.) microplus among the sampled farms was 66.6% (18/27). Out of these 18 areas, resistance to deltamethrin at level I was detected in 08 areas (resistance factor=2.0-4.9), at level II in 09 areas (RF=5.2-11.8), at level III in 01 area (RF=34.9) and at level IV in 01 area (RF=95.7). The resistance to cypermethrin was detected in 16 areas and level of resistance was detected at level I in 10 areas (RF=2.06-4.64) and at level II in 06 areas (RF=5.13-9.88). The middle-gangetic and trans-gangetic plains revealed higher density of resistant ticks where intensive cross bred cattle population are reared and the SP compounds are commonly used. The data generated on acaricide resistant status in ticks will help in formulating tick control strategy for the country.     

Assessing impact of climate change on forest cover type shifts in Western Himalayan Eco-region

Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate (temperature, precipitation, drought, wind etc.). Available information is not sufficient to support a quantitative assessment of the ecological, social and economic consequences. The present study assessed shifts in forest cover types of Western Himalayan Eco-region (700?4500 m). 100 randomly selected samples (75 for training and 25 for testing the model), genetic algorithm of rule set parameters and climatic envelopes were used to assess the distribution of five prominent forest cover types (Temperate evergreen, Tropical semi-evergreen, Temperate conifer, Subtropical conifer, and Tropical moist deciduous forests). Modelling was conducted for four different scenarios, current scenario, changed precipitation (8% increase), changed temperature (1.07°C increase), and both changed temperature and precipitation. On increasing precipitation a downward shift in the temperate evergreen and tropical semi-evergreen was observed, while sub-tropical conifer and tropical moist-deciduous forests showed a slight upward shift and temperate conifer showed no shift. On increasing temperature, an upward shift in all forest types was observed except sub-tropical conifer forests without significant changes. When both temperature and precipitation were changed, the actual distribution was maintained and slight upward shift was observed in all the forest types except sub-tropical conifer. It is important to understand the likely impacts of the projected climate change on the forest ecosystems, so that better management and conservation strategies can be adopted for the biodiversity and forest dependent community. Knowledge of impact mechanisms also enables identification and mitigation of some of the conditions that increase vulnerability to climate change in the forest sector.     

Seasonal variations in species diversity, dry matter and net primary productivity of herb layer of Quercus leucotrichophora-Pinus roxburghii mixed forest in Kumaun Himalaya, India

Plant biomass, species diversity and net primary productivity are presented for herb layer of banj oak (Quercus leucotrichophora A. Camus)-chir pine (Pinus roxburghii Sarg.) mixed forest in Kumaun, central Himalaya, India. The species diversity declined from a maximum (3.56) in September to a minimum (2.11) in December. The monthly live shoots biomass exhibited a single peak growth pattern with highest live shoot biomass of 185 g·m-2 in August. The seasonal pattern showed that the maximum above-ground production (131 g·m-2) occurred during the rainy season and the minimum (1 g·m-2) during winter season. The below-ground production was maximum during winter season (84 g·m-2) and minimum during summer season (34 g·m-2). The annual net shoot production was 171 g·m-2 and total below-ground production was 165 g·m-2. Of the total input 61% was channeled to above-ground parts and 39% to below-ground parts. Transfer of live shoots to dead shoots compartments and that of dead shoots to litter compartments was 61% and 66%, respectively. The total dry matter disappearance was 61% of the total input within annual cycle. The herb layer showed a net accumulation of organic matter, indicating the seral nature of the community.