The Orthocladiinae (Diptera: Chironomidae) of India genus Cricotopus van der Wulp

This is the eleventh part of our series of studies on Orthocladiinae from India. Two new species of the genus Cricotopus, C. albipes and C. tenuisetosus are described in this paper.     

Mechanism of endotoxin-induced reduction in the number of beta-adrenergic receptors in dog livers: role of phospholipase A

The role of phospholipase A on the endotoxin-induced reduction in the number of beta-adrenergic receptors in dog liver plasma membranes was investigated. The results show that digestion of control liver plasma membranes with exogenous phospholipase A2 (0.2 unit/200 micrograms protein) decreased the specific binding of (-)-[3H]dihydroalprenolol by 37.3% (P less than 0.01) and reduced the number of receptor sites by 31.7% (P less than 0.05). These decreases in the specific binding and the number of beta-adrenergic receptors were completely reversible by the addition of phosphatidylcholine (0.2 mM). Endotoxin administration (2 hr postendotoxin) decreased the specific binding by 36% (P less than 0.05) and reduced the number of beta-adrenergic receptors by 33% (P less than 0.05), and these decreases were completely reversible by the addition of 0.2 mM phosphatidylcholine. Digestion of control liver membranes with exogenous phospholipase A2 decreased phosphatidylcholine and phosphatidylethanolamine levels by 50.6 and 51.2%, respectively, but increased lysophosphatidylcholine and lysophosphatidylethanolamine levels by 12- and 8.4-fold, respectively. Endotoxin administration decreased phosphatidylcholine and phosphatidylethanolamine contents by 21.4 and 23.8%, respectively, but increased lysophosphatidylcholine and lysophosphatidylethanolamine contents by 2.1- and 1.4-fold, respectively. In addition, endotoxin administration increased endogenous phospholipase A activity by 73.5%. Based on these results, it is suggested that the decreases in the specific binding and the number of beta-adrenergic receptors in dog livers during endotoxic shock are a result of phospholipase A activation.     

The role of Asn14 in the stability and conformation of the reactive-site loop of winged bean chymotrypsin inhibitor: crystal structures of two point mutants Asn14-->Lys and Asn14-->Asp.

A double-headed chymotrypsin inhibitor, WCI, from winged bean seeds was cloned for structural and biochemical studies. The inhibitor was subjected to two point mutations at a conserved position, Asn14. This residue, known to have a pivotal role in stabilizing the first reactive-site loop (Gln63-Phe68) of the inhibitor, is highly conserved in the sequences of the other members of Kunitz (STI) family as well as in the sequences of Kazal family of serine protease inhibitors. The mutants, N14K and N14D, were subjected to biochemical assay and their characteristics were compared with those of the recombinant inhibitor (rWCI). Crystallographic studies of the recombinant and the mutant proteins are discussed. These studies were primarily aimed at understanding the importance of the protein scaffolding towards the conformational rigidity of the reactive-site loop. Our analysis reveals that, as the Lys14 side chain takes an unusual fold in N14K and the Asp14 side chain in N14D interacts with the loop residues by water-mediated hydrogen bonds, the canonical conformation of the loop has remained effectively intact in both the mutant structures. However, minor alterations such as a 2-fold increase in the inhibitory affinity towards the cognate enzyme were observed.     

Experimental alterations of the spores of lycopodium clavatum as related to diagenesis

Lycopodium clavatum spores have been heated to different temperatures at atmospheric pressure, at room temperature with 0.5 kbar pressure and at different temperatures with 1 kbar pressure, The effects of heat, pressure, and heat and pressure together on the spore have been examined in detail using different microscope techniques. Effects of some chemicals on these spores have also been observed.It is known that temperature and pressure change the colour of spore and pollen grain walls, mainly the exine (outer wall of the spore). Changes to the intine and the matter present in the cytoplasmic cavity (= inner contents), however, have not been taken into account by very many workers. In most of the previous works the inner contents were extracted before the experimental treatment began.In the present work, unextracted spores are used for the experiments which show two types of alterations of the spores with rising temperature at atmospheric pressure: (1) alteration of the inner contents, i.e. gradual colour change of the inner contents and their ultimate exudation from the spore through the exine at about 300°C; (2) gradual shrinkage of the exine due to the exudation of the inner contents which also causes an overall size reduction of the spore from 200° to 350°C. The exine does not change its colour up to 325°C; and this temperature, its starts to change its colour slowly, amalgamates with other exines of the empty spores, becomes amorphous, and ultimately deteriorates into unidentifiable organic matter.The process of colour change of the inner contents of spores and the general deformation are much slower when the spores are subjected to 1 kbar pressure with rising temperatures. Spores at room temperature with 0.5 kbar pressure show no colour change but only physical deformation.     

Seasonal Abundance of Acanthamoeba rhysodes (Singh, 1952) (Protozoa: Gymnamoebia) in a Mangrove Litter-Soil Ecosystem of Gangetic-Estuary,India1,2

Acanthamoeba rhysodes has been found to be a predominant intertidal benthic gymnamoeba in the mangrove ecosystem of Sundarbans of lower deltaic Bengal, facing the Bay. The sampling zones under study were the highest high tide regions, with characteristic mangrove litter-soil, inundated twice per month during the highest ebb of spring tide. Population abundance of this species, both in its trophic and cystic forms in the three distinct seasonal periods of pre-monsoon (March to June), monsoon (July to October), and post-monsoon (November to February) has been surveyed for over two years. These seasonal periods affect the physico-chemical parameters of the habitat substrata, including temperature, pH, and salinity. It has been found that the overall number of organisms per gram of soil attains peak value during the monsoon period. This value comes down in post-monsoon samples and is the least in pre-monsoon ones.     

Vasculature of the head and respiratory organs in an obligate air-breathing fish,the swamp eel Monopterus (=Amphipnous) cuchia

Methyl methacrylate vascular corrosion replicas were used to examine the macrocirculation in the head region and the microcirculation of respiratory vessels in the air-breathing swamp eel Monopterus cuchia. Fixed respiratory tissue was also examined by SEM to verify capillary orientation. The respiratory and systemic circulations are only partially separated, presumably resulting in supply of mixed oxygenated and venous blood to the tissues. A long ventral aorta gives rise directly to the coronary and hypobranchial arteries. Two large shunt vessels connect the ventral aorta to the dorsal aorta, whereas the remaining ventral aortic flow goes to the respiratory islets and gills. Only two pairs of vestigial gill arches remain, equivalent to the second and third arches, yet five pairs of aortic arches were identified. Most aortic arches supply the respiratory islets. Respiratory islet capillaries are tightly coiled spirals with only a fraction of their total length in contact with the respiratory epithelium. Valve-like endothelial cells delimit the capillary spirals and are unlike endothelial cells in other vertebrates. The gills are highly modified in that the lamellae are reduced to a single-channel capillary with a characteristic three-dimensional zig-zag pathway. There are no arterio-arterial lamellar shunts, although the afferent branchial artery supplying the gill arches also supplies respiratory islets distally. A modified interlamellar filamental vasculature is present in gill tissue but absent or greatly reduced in the respiratory islets. The macro- and micro-circulatory systems of M. cuchia have been considerably modified presumably to accommodate aerial respiration. Some of these modifications involve retention of primitive vessel types, whereas others, especially in the microcirculation, incorporate new architectural designs some of whose functions are not readily apparent.     

Keratinophilic fungi from Orissa, India, II: Isolations from feathers of wild birds and domestic fowls

Feather samples from 117 birds, representing 11 species, were examined for keratinophilic fungi. Of these, 63 (53.8%) were found to be positive. Nine species of fungi classified in 6 genera were isolated: Aphanoascus terreus (1.7%), Chrysosporium indicum (26.4%), Chrys. tropicum (11.1%) the Chrysosporium state of Aphanoascus spp. (2.5%), the Chrysosporium state of Arthroderma tuberculatum (3.4%), Ctenomyces serratus (0.8%), Gymnoascoideus petalosporus (7.6%), Malbranchea spp. (6.8%), Rollandina hyalinospora (6.8%). Passer domesticus (the house sparrow) harboured the largest varieties of keratinophilic fungi: the Chrysosporium state of Arthroderma tuberculatum was found to be associated with it selectively. The associations of these keratinophilic fungi with birds were non-clinical in nature.     

Anemia in experimental visceral leishmaniasis in hamsters.

Experimental infection of hamsters with Leishmania donovani caused visceral leishmaniasis in which hematological changes occurred. The infected hamsters were anemic and reticulocyte counts were high. No significant change in the serum erythropoietin level was noted. Red cell membrane Na(+)-K(+)-ATPase and acetylcholinesterase activities increased. Osmotic fragility of the erythrocytes from infected animals increased. The level of 2,3-diphosphoglycerate of the red cells increased with the degree of anemia.