Impact of alphamethrin on biochemical parameters of Channa punctatus.

Impact of alphamethrin (synthetic pyrethroid) on profiles of lactate dehydrogenase (LDH), catalase (CAT), DNA, RNA and protein in liver, brain, gill and skeletal muscle of the freshwater food fish Channa punctatus were investigated. Exposure of sublethal concentration of alphamethrin (0.018 ppm for 14 days) increased the activity of LDH in liver (1.8 fold), brain (1.4 fold), gill(1.6 fold), and skeletal muscle(2.2 fold) of the fish. However, it significantly decreased the activity of CAT in the tissues of liver (54%), skeletal muscle (52%), gill (51%) and brain (49%) of the fish. Similarly, DNA (skeletal muscle (36%), liver (30%), brain (28%) and gill (25%)) RNA (liver (42%), brain (32%), gill (35%) and skeletal muscle (45%) ) and protein content (45%), brain (42%), gill (36%), and skeletal muscle (27%)) declined in different tissues of the fish exposed to alphamethrin. Maximum increase in the level of LDH was in skeletal muscle (2.2 fold) and minimum in brain (1.4 fold). Maximum reduction in CAT profile was in liver (54%), and minimum in brain (49%). Declines in DNA was maximum in skeletal muscle (36%) and minimum in gill (25%) whereas RNA and protein content were maximum in liver (42% and 45% respectively) and minimum in skeletal muscle (45% and 27% respectively). Alphamethrin was toxic to the freshwater fish due to its inducing effect on anaerobic enzyme (LDH) and inhibitory effect on antioxidant enzyme (CAT), DNA, RNA and protein. This reflected alphamethrin associated increase in anaerobiosis and decrease in oxidative defense and impairment in protein synthesizing capacity of C. punctatus. Further, induction in LDH and reduction in CAT and protein profile may be used as biomarker of alphamethrin toxicity in fish.

Temperature-dependent alterations in metabolic enzymes and proteins of three ecophysiologically different species of earthworms

The effects of varying temperatures (12 - 44° C) on the specific activity of cytoplasmic malate dehydrogenase ((cMDH), mitochondrial malate dehydrogenase (mMDH) and lactate dehydrogenase (LDH) of some earthworms (Metaphire posthuma, Perionyx sansibaricus and Lampito mauritii) were studied. The effects of different temperatures on supernatant and mitochondrial protein contents were also investigated. The specific activities of cMDH, mMDH and LDH of the earthworms decreased gradually as a function of increasing temperature from 12 to 44°C. Higher metabolic energy was needed to maintain the activity at low temperatures. Hence, the earthworms showed increased enzyme specific activity at low temperatures. However, the protein content increased upto 28°C. Afterwards, with the increase in the temperature from 28 to 42°C, the proteins in the earthworms showed a significant decrease. The temperature-associated changes in the protein content could be explained by the fact that protein synthesizing capacity was hampered above and below the optimum temperature range. The most pronounced effects of varying temperatures were on P. sansibaricus. It might be due to the epigeic nature of the earthworm species. Then minimum effect was on the endogeic earthworm M. posthuma. Virtually, the differences in the enzymes physiology were associated with the differences in the ecological categories of the earthworms. This clearly demonstrate a possible link between the physiology and ecology at aerobic (cMDH, mMDH) and anaerobic (LDH) levels in the tropical earthworms.

Mesofaunal biodiversity and its importance in Thar desert.

Soil animals are considered as important contributors to soil fertility However, there is paucity of such information for harsh climatic conditions. Therefore, the below ground faunal density and frequency have been studied in relation to physicochemical properties of soil in Thar desert. The selected soil systems were Vigna radiata--Cuminum cyminum, grassland, flower garden and Zizyphus mauritiana. Acari and other soil arthropods exhibited seasonal variation in their populations. There were two population peaks, one in February/March and other in August/September. The highest population was in flower garden, whereas lowest was in Z. mauritiana field. It clearly indicates that the soil fauna population develops in different degrees. The relative density showed that the acarines were more prevalent in comparison to other soil arthropods. The prostigmatids exhibited maximum relative density in comparison to cryptostigmatids and mesostigmatids in all fields. Pauropus showed higher relative density among all other soil arthropods. Acari had higher frequency of occurrence, while the other soil arthropods indicated lower frequency of occurrence in all systems. The highest frequency of occurrence was recorded in July/August and the lowest in May/June. The soil temperature, moisture, organic carbon, total nitrogen and carbon/nitrogen ratio varied significantly throughout the year The fluctuations in physicochemical characteristics of soil greatly influenced below ground faunal density in different fields. A highly significant and positive correlation was obtained among different soil fauna groups. Faunal population showed a significant positive correlation with soil moisture, organic carbon and total nitrogen. The abiotic factors such as temperature, pH and C/N ratio showed negative correlation with moisture, organic carbon and total nitrogen. However, moisture, organic carbon and total nitrogen had positive correlation among themselves. The present study suggests that the plantation may be done for improvement of physicochemical and biological health of soil on a sustainable basis in desert.

Temperature related seasonal changes in Golgi complex of brain, heart and intestine of a teleost.

Impact of temperature related seasonal changes in density of Golgi complex were studied in brain, heart and intestine of the freshwater catfish, Clarias batrachus (Linnaeus). The density of Golgi complex was more in these organs of the fish acclimatized to a lower temperature (20 degrees C) than that to a higher temperature (29 degrees C). This suggests that lower temperature induces secretory activity in cells to cope up with the changes in surrounding environment. It could be a kind of histophysiological adaptation in poikilothermic animal.

Biodiversity of earthworm resources of arid environment.

Biodiversity of earthworms was studied in arid zone of Jodhpur district of Rajasthan. A total nine species of earthworms were recorded from different pedoecosystems of desert environment. These species were Pontoscolex corethrurus, Amynthas morrisi, Metaphire posthuma, Lampito mauritii, Perionyx sansibaricus, Ocnerodrilus occidentalis, Dichogaster bolaui, Octochaetona paliensis and Ramiella bishambari. They belonged to the families Glossoscolicidae, Megascolicidae, Ocnerodrilidae and Octochaetidae. The species P. sansibaricus, O. paliensis and P. corethrurus were reported for the first time from Rajasthan. The earthworm fauna of Jodhpur district were either exotic peregrine or native peregrine. Exotic species like A. morrisi and M. posthuma, and native peregrine species like L. mauritii were widely distributed in arid region. They appear to be better adapted to withstand drought conditions, as they have enteronephric meronephridia and excrete their urine into the guts for conservation of water in their bodies.

Seasonal changes in population of some selected earthworm species and soil nutrients in cultivated agroecosystem.

Studies were conducted on population dynamics of Metaphire posthuma, Lampito mauritii and Dichogaster bolaui in cultivated pedoecosystem of desert region of Rajasthan. The populations of aclitellate and clitellate M. posthuma, L. mauritii and D. bolaui were maximum in rainy season and minimum in summer season. The abundant population of these worms were found during the months of July to October. The species M. posthuma breed throughout the year except in extreme summer but L. mauritii breed twice in a year in the field. However, D. bolaui breed once in a year. Among these earthworm species D. bolaui with relative density of 44.2% was the most dominant species in cultivated land while L. mauritii and M. posthuma contributed 33.3% and 22.5% of density, respectively. The total population of earthworms showed significant positive correlation with different soil nutrients.

Fenvalerate-induced macromolecular changes in the catfish, Clarias batrachus.

The effects of sublethal concentration of fenvalerate on DNA, RNA, RNA/DNA ratio and protein contents were estimated in gill and kidney tissues of an air breathing fish, Clarias batrachus. Fenvalerate reduced the DNA content in gill, whereas it did not produce any significant effect on DNA in kidney. This tissue-specific change in DNA content may be due to differential effects of fenvalerate or its metabolite(s) on synthesis and/degradation of DNA in gill and kidney cells of the fish. RNA and protein contents declined substantially in both the tissues in response to fenvalerate treatment. However, RNA/DNA ratio remains unchanged. It indicates that decrease in protein content in response to fenvalerate treatment might have been brought about by reduce rate of translation of messenger (mRNA) without a decrease in concentration of ribosomes.

Effect of estradiol dipropionate on uterine and vaginal glycogen content of Parkes (P) mice.

Administration of estradiol dipropionate (20 micrograms/day: for 7 days) to ovariectomized (7 days) mice produced about three fold increase (180%) in uterine glycogen content while approximately four fold decrease (76%) in vaginal glycogen as compared to their control values. Differences in glycogen content after 7 and 14 days of ovariectomy were statistically insignificant in both the organs. Although estradiol dipropionate had a great effect on the glycogen content of uterus and vagina but this effect remained more or less unchanged after causing alteration in duration (7 and 14 days) of estradiol dipropionate treatment in relation to different time intervals (7 and 14 days) after ovariectomy. So there was no time dependent response in uterine and vaginal glycogen content after 7 days onwards either in relation to ovariectomy or estradiol dipropionate treatment. The opposite trend (increase in uterus and decrease in vagina) of glycogen content in response to estradiol dipropionate may be possibly due to a greater accumulation (than utilization) in uterus while greater consumption (than accumulation) in vagina.