A. Choudhury

Bio: A. Choudhury is an academic researcher from University of Calcutta. The author has contributed to research in topics: Sterol & Avicennia officinalis. The author has an hindex of 9, co-authored 22 publications receiving 375 citations. Previous affiliations of A. Choudhury include Bose Institute.

Histopathology of Trypanosoma (Trypanozoon) evansi infection in Bandicoot rat. II. Brain and choroid plexus

Abstract: Bandicoot rat, Bandicota bengalensis, received intraperitoneal inoculation of Trypanosoma (Trypanozoon) evansi flagellates and showed acute disease, leading to death during the 2nd peak of parasitaemia [14th day post infection (pi)]. Damage in brain and choroid plexus of the infected bandicoot is studied on the 5th, 8th, 12th and 14th day post inoculation. Sign of histopathological changes in the brain and choroid plexus of the bandicoot are detected after 1st peak of parasitaemia. Infiltration of lymphocyte and plasma cells, congestion, perivascular cuffing, gliosis and brain lesions are observed during 12th–14th day post intection. Multiple sclerosis, neuronophagia, focal haemorrhage, cerebral hyperplasia, oligodendrocytoma, astrocytoma and fatty degeneration of brain tissue are also found. Alteration in the ependymal cells of choroid plexus is noticed. Extensive oedema, infiltration of inflammatory cells and rupture of ventricular ependymal layer are found. Parasites are found both in the brain tissue and choroid plexus. No intracellular stage of the parasite is observed. The nature of damage in the brain tissue and choroid plexus shows similarity with the cases of African trypanosomiasis. This salivarian species cause more deleterious effect in brain much earlier in the disease course than its African relatives.

Bioactivities, bioactive compounds and chemical constituents of mangrove plants

Abstract: This review article presents the traditional and medicinal uses, and examines recent investigations on the biological activities of extracts, and chemicals identified from mangroves and mangal associates. Metabolites identified from mangrove plants are classified according to ‘chemical classes’, and some of their structures are illustrated. The article also presents some of the functions of the chemicals present and attempt to emphasize and create an awareness of the great of potential mangroves and mangal associates possess as a source of novel agrochemicals, compounds of medicinal value, and a new source of many already known biologically active compounds.

Ecology of Free-Living Amoebae

Abstract: Small free-living amoebae (FLA) are the main predators controlling bacterial populations in soils. They are distributed in the rhizospheric zone and the surrounding bulk soil; however, they may spread deeper, reaching the vadose zone of groundwater systems, especially where bacterial populations get to high densities. Soil texture is the physical factor controlling the distribution of FLA because it determines the mean bore pore of soil aggregates and other important physical factors. FLA help maintain the high bacterial mineralization rate of organic matter through predation. As attachment onto a surface is necessary for feeding, the quantity of available surfaces is very important for developing this activity. However, the role of protozoa on plant growth promotion is still unclear because they may increase this effect by feeding on both fungi and bacteria. Small FLA are found in soils or sediments, as well as attached to suspended particulate matter in water columns, in the first 30 pm of water surface, or on the bodies of submerged animals and plants. These microor- ganisms do not distinguish between terrestrial or aquatic environments because they live in the interfaces between them. However, their importance in aquatic systems has been considered as negligible because they are outcompeted by free swimmers. The water conditions affecting amoebae survival are pH, temperature, concentration of sulfhydric acid and salinity. These factors have a strong influence on the structure of amoebae communities in aquatic environments. FLA are considered cosmopolitan as a group, and they live inside vertebrates, in soils, freshwater, marine waters, and on the aerial parts of plants and animals. These microbes, are spread by wind and water currents. Once in the air, cysts and trophozoites behave like any other suspended particulate matter. Therefore, suspension, transportation, and removal depend on atmospheric dynamics rather than on their own mechanisms. Ultraviolet light and drought are the main causes of losing viability, but much needs to be learned about the effects of air contaminants on amoebal survival. Naked amoebae also live in the phyllosphere as part of phylloplane community, but their importance and participation in this environment remain unknown. Some species belonging to the genera Acantharnoebae, Naegleria, and Balamuthia cause fatal diseases in humans and are carriers of other pathogens such as Legionella pneumophilia. However, FLA communities can be of some utility in sewage treatment works based in soil filters. %A's predatory activity in the root zone method may be of greater importance than previously thought, because this is their natural or more favorable environment. Research on the feeding behavior of FLA species, their rate of biomass transformation, and growth rate changes in response to environmental stresses are still needed in order to clarify their importance in both sewage system works and agricultural fields, where both bacteria and amoebae are involved.

DNA barcoding and surveillance sampling strategies for Culicoides biting midges (Diptera: Ceratopogonidae) in southern India

Abstract: Culicoides spp. biting midges transmit bluetongue virus (BTV), the aetiological agent of bluetongue (BT), an economically important disease of ruminants. In southern India, hyperendemic outbreaks of BT exert high cost to subsistence farmers in the region, impacting on sheep production. Effective Culicoides spp. monitoring methods coupled with accurate species identification can accelerate responses for minimising BT outbreaks. Here, we assessed the utility of sampling methods and DNA barcoding for detection and identification of Culicoides spp. in southern India, in order to provide an informed basis for future monitoring of their populations in the region. Culicoides spp. collected from Tamil Nadu and Karnataka were used to construct a framework for future morphological identification in surveillance, based on sequence comparison of the DNA barcode region of the mitochondrial cytochrome c oxidase I (COI) gene and achieving quality standards defined by the Barcode of Life initiative. Pairwise catches of Culicoides spp. were compared in diversity and abundance between green (570 nm) and ultraviolet (UV) (390 nm) light emitting diode (LED) suction traps at a single site in Chennai, Tamil Nadu over 20 nights of sampling in November 2013. DNA barcode sequences of Culicoides spp. were mostly congruent both with existing DNA barcode data from other countries and with morphological identification of major vector species. However, sequence differences symptomatic of cryptic species diversity were present in some groups which require further investigation. While the diversity of species collected by the UV LED Center for Disease Control (CDC) trap did not significantly vary from that collected by the green LED CDC trap, the UV CDC significantly outperformed the green LED CDC trap with regard to the number of Culicoides individuals collected. Morphological identification of the majority of potential vector species of Culicoides spp. samples within southern India appears relatively robust; however, potential cryptic species diversity was present in some groups requiring further investigation. The UV LED CDC trap is recommended for surveillance of Culicoides in southern India.