Impact of age of rubber (Hevea brasiliensis) plantation on earthworm communities of West Tripura (India).

A comparative analysis of earthworm communities was carried out in the rubber plantations (Hevea brasiliensis) of different age groups in West Tripura to understand the impact of such exotic and monoculture plantation in biodiversity conservation. Earthworm communities were studied on monthly basis over a period of one year (2006-2007) in the 3, 10, 14, 20 and 25 year-old plantations. Among twelve earthworm species collected from the studied sites, six species belonged to Octochaetidae [Eutyphoeus assomensis Stephenson, Eutyphoeus comillahnus Michaelsen, Lennogaster chittagongensis (Stephensen), Octochaetona beatrix Gates, Dichogaster offinis Michaelsen, Lennogaster yeicus (Stephensen)], two species each to Megascolecidae [Metaphire houlleti (Perrier), Konchurio sp. 1] and Moniligastridae [Drowida nepalensis Michaelsen, Drawida papillifer papillifer Stephenson], one species each to Glossoscolecidae [Pontoscolex corethrurus (Muller)] and Ocnerodrilidae [Gordiodrilus elegans Beddard]. Exotic species P corethrurus, M. houlleti and native peregrine species like D. nepolensis and D. papillifer papillifer were distributed in all the age groups of plantation, while other species showed restricted distribution. P. corethrurus contributed more than 60% biomass and 70% density of earthworm communities in rubber plantation. With aging of rubber plantations both the densities and biomasses of earthworms increased. High contents of polyphenol, flavonoid and lignin in the litters of 3 and 10 year-old-rubber plantations through their effects on food intake, probably resulted to low biomass values of earthworms in those age groups of plantation. With further increase in the age of plantations beyond 10 years, polyphenol, flavonoid and lignin contents decreased. Accordingly the biomass of earthworms increased with increase in the age of plantation. Soil moisture increased with increase in the age of plantation and there was a good positive correlation between soil moisture and earthworm biomass (p < 0.01). Density, biomass and dominance of earthworms increased while species diversity, species richness and species evenness of earthworm community were decreased with increase in the age of rubber plantation.

Effects of five earthworm species on some physico-chemical properties of soil.

An incubation experiment was conducted to study the changes that occur in organic carbon content, phosphorous and potassium availability and other soil properties with ingestion of soil mixed with rubber leaf litter and cow dung by five earthworm species viz. Pontoscolex corethrurus, Drawida assamensis, Drawida papillifer papillifer, Eutyphoeus comillahnus and Metaphire houlletiof rubber plantation in Tripura (India). Due to earthworm activity organic C (1.56-1.63%) and available P (14.71-27.60 mg 100 g(-1)) and K (43.50-49.0 mg 100 g(-1)) content of the soil increased significantly (p < 0.05) in most of the earthworm species studied. M. houlleti and D. papillifer papillifer had the highest P (27.60 mg 100 g ) and K (49.0 mg 100 g ) mobilization capacity, respectively. Earthworms, irrespective of the species, increased the pH (7.05-7.17) and electrical conductivity (663-1383 microS cm(-1)) of the soil significantly (p < 0.05).

Community structure of earthworms under rubber plantations and mixed forests in Tripura, India.

Studies on community structures of earthworms of rubber (Hevea brasiliensis) plantations and their adjacent mixed forests in West Tripura (India) revealed that both the studied sites harvoured 10 earthworm species. Nine species (Pontoscolex corethrurus, Kanchuria sp 1, Metaphire houlleti, Drawida papillifer papillifer, Drawida assamensis, Gordiodrilus elegans, Eutyphoeus assamensis, Eutyphoeus comillahnus and Eutyphoeus gigas) were common to both. While Octochaetona beatrixwas found only in the rubber plantations, Dichogaster affinis was restricted to the mixed forest only. Earthworms were found mostly within 15 cm depth of soils having mean temperature of 27 degrees C, moisture of 23%, pH of 4.57, organic matter of 1.34% and water holding capacity of 36%. Mean earthworm density in rubber plantations (115 ind. m(-2)) was significantly higher (p = 0.003, t = 3.83) than that in the mixed forests (69 ind. m(-2)) due to dominance of Pontoscolex corethrurus, an exotic species. Numbers of dominant species were two (P. corethrurus and D. assamensis) in the rubber plantations and five (P. corethrurus D. assamensis, D. papilliferpapillifer, M. houlleti and Kanchuria sp 1) in the mixed forests. Compared to the mixed forests, significantly low (p<0.05) Shannon diversity index (H) and species evenness and high index of dominance in the rubber plantation were evaluated.

Superoxide dismutase and total anti-oxidant levels in various forms of liver diseases.

In order to understand the impact of viral hepatitis on anti-oxidant defence system of the body, blood levels of superoxide dismutase (SOD), an enzymatic anti-oxidant, and total anti-oxidant (TAO) were evaluated and co-related to etiological viral hepatitis in various forms of liver diseases. A total number of 110 patients including 50 patients with acute viral hepatitis (AVH), 30 patients with chronic active hepatitis (CAH) and 30 patients with cirrhosis of liver were analysed for different hepatitis viral markers and the anti-oxidant levels in their blood. For comparison, blood from 100 healthy persons were also simultaneously tested for anti-oxidant levels. Analysis of results indicated that none of the patients belonging to these three liver diseases had hepatitis A viral (HAV) and hepatitis D viral (HDV) infections. AVH group had mainly hepatitis B viral (HBV), hepatitis C viral (HCV) and hepatitis E viral (HEV) infections, CAH group had B and C infections and cirrhosis group had B, C and E infections. A sizeable number of patients in each group had no markers and were labelled as non-BCE group. On co-relating anti-oxidant levels to viral etiology in these patients, it was observed that in comparison to healthy control group, SOD level was significantly reduced in all the patients irrespective of the viral etiology (P<0.05-0.001). The impact of different viruses on reduction in SOD level was recorded to be the same with no significant difference in SOD level between any two viral infections. On the contrary, TAO level in the majority of patients was found to be comparable with that observed in healthy persons. An appreciable change in SOD level but little impact on TAO level during viral hepatitis may be explained by the possible adaptive rise of some other anti-oxidant level in the blood of these patients.

Cocoon production, morphology, hatching pattern and fecundity in seven tropical earthworm species - a laboratory-based investigation.

Data on the reproductive biology of seven Indian species of earthworms, viz. Perionyx excavatus Perrier, Lampito mauritii Kinberg, Polypheretima elongata (Perrier), Pontoscolex corethrurus (Muller), Eutyphoeus gammiei (Beddard), Dichogaster modiglianii (Rosa) and Drawida nepalensis Michaelsen are presented. The peregrine earthworms such as Perionyx excavatus, Pontoscolex corethrurus, Dichogaster modiglianii, and Polypheretima elongata are considered to be continuous breeders with high fecundity. Native Lampito mauritii and Drawida nepalensis are semi-continuous and Eutyphoeus gammiei discrete breeders. There is a dramatic increase in cocoon production by most earthworm species of Tripura in the summer and monsoon with a corresponding peak during April and July. Cocoon production decreased or ceased during winter. Temperature affected the incubation period of cocoons. With increase in temperature, incubation period increased in the endogeic worms, Pontoscolex corethrurus, Polypheretima elongata and Drawida nepalensis and decreased in the epigeic worms, Perionyx excavatus and Dichogaster modiglianii, within a temperature range between 28-32 degrees C under laboratory conditions. There was a significant (P < 0.05) positive correlation between number of hatchlings per cocoon and incubation period in Lampito mauritii. High rate of cocoon production, short development time with high hatching success, as well as continuous breeding strategies in the epigeic species Perionyx excavatus and Dichogaster modiglianii and the top soil endogeic species, Pontoscolex corethrurus, Drawida nepalensis and Lampito mauritii, indicate their possible usefulness in vermiculture. The giant anecic worm, Eutyphoeus gammiei, which has a very long cocoon development time, discrete breeding strategy and very low rate of cocoon production, is not a suitable species for vermiculture.

Capacity of various experimental diets to support biomass and reproduction of Perionyx excavatus.

Biomass production and reproduction of a group of four adult Perionyx excaratus were studied in limited supplies of four experimental diets; cowdung alone and its mixtures with straw, bamboo leaf litter or kitchen waste, in order to select a suitable diet medium for vermiculture. P. excavatus showed maximum rate of biomass increase and reproduction in the mixtures with straw and bamboo leaf litter. In spite of achieving the highest final biomass value. P. excavatus showed the lowest rate of biomass increase and reproduction in the mixture with kitchen waste. Cowdung, a natural food of P. excavatus, was marginally better than the mixture with kitchen waste with regard to the rate of biomass increase and reproduction.

Oxidant-antioxidant system: role and significance in human body.

Present article gives a holistic view of the causes, role and conrol of oxidative stress in the development and progression of various human diseases. Several types of reactive species are generated in the body as a result of metabolic reactions in the form of free radicals or non-radicals. These species may be either oxygen derived or nitrogen derived and called prooxidants. They attack macromolecules including protein, DNA and lipid etc. causing cellular/tissue damage. To counter their effect, the body is endowed with another category of compounds called antioxidants. These antioxidants are produced either endogenously or received from exogenous sources and include enzymes like superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, minerals like Se, Mn, Cu and Zn, and vitamins like vitamin A, C and E. Other compounds with antioxidant activity include glutathione, flavonoids, bilirubin and uric acid etc.. In a healthy body, prooxidants and antioxidants maintain a ratio and a shift in this ratio towards prooxidants gives rise to oxidative stress. This oxidative stress may be either mild or severe depending on the extent of shift and remains the cause of several diseases such as cardiovascular diseases, neurological diseases, malignancies, renal diseases, diabetes, inflammatory problems, skin diseases, aging, respiratory diseases, liver diseases and different types of viral infections. As more and more reports are pouring in, a lot of information is being unfolded about oxidative stress in relation to several other diseases.

Cytomorphic studies on the neurosecretory cells in the central nervous system of the Indian horseshoe crab Carcinoscorpius rotundicauda (Latrielle).

The central nervous system of Carcinoscorpius rotundicauda contains two types of NSCs (A and B) differing as regards their size, cytoarchitecture and distribution. They are clearly distinguishable when stained with azan and Masson's trichrome, but react weakly to PAF and CHP. The A cells are large, with fine cytoplasm granules (NSM), and are distributed below the perineurium, while the B cells are much smaller, contain coarse granules and are distributed in the vicinity of the neuropil. The posterior third of the circumoesophageal ring and the abdominal ganglia contain a far larger number of NSCs compared to the anterior part of the CNS. The ability of NSC groups to form numerous axon bundles, decussation of the neurosecretory axons, the presence of a rich capillary network round neurosecretory perikaryons and the appearance of atypical neurons in the anteromedian part of the CNS are further striking features discussed with reference to the neurosecretory phylogeny of the species in question.