Chromosomal heteromorphisms in Delhi infants. III. Qualitative analysis of C-band inversion heteromorphisms of chromosomes 1, 9, and 16

Qualitative analysis of C-band heteromorphisms was carried out in 200 infants (100 males and 100 females) in Delhi, India. Partial inversions minor and half inversions were observed as modal levels for chromosomes 1 and 9 in both sexes. No chromosome 16 with a C-band inversion was observed in the present investigation. A significantly higher incidence of percent inversions for chromosomes 1 and 9 was observed in males than in females. The frequency of heterozygous inversion level combinations for chromosome pairs 1 and 9 were remarkably higher than homozygous combinations both in males and females. Our results are compared with the other reported studies, and the possible role of these heteromorphisms in ethnic/racial variation and in developmental disturbances are discussed.     

Mechanism of Copper Resistance in a Copper Mine Isolate Pseudomonas putida Strain S4

The mechanism of copper resistance in a multiple-metal-resistant natural isolate Pseudomonas putida strain S4 is based on inducible efflux. Active extrusion of copper ions occurs from the cytoplasm during the exponential phase of growth. Involvement of ATPase in the efflux of copper ions has been demonstrated by employing specific inhibitors. The effluxed copper is not thrown out of the cell, but remains in a bound form (to a protein) in the periplasm. Thus, a balance between the intracellular level, to fulfill the metabolic requirements, and the periplasmic sequestration, to evade toxicity, is maintained by this isolate. Received: 11 February 2002 / Accepted: 7 March 2002     

Quantitative estimation of islet tissue of pancreas in adult Grey kangaroos (Macropus fuliginosus)

Six Grey kangaroos, both male and female, were shot and weighed. The pancreas was isolated, weighed and samples fixed in Bouin's solution. Using a linear scanning technique (Carpenter & Lazarow, 1962) the mean islet tissue mass was estimated in head, neck, body and tail regions. A uniform distribution was found in all regions. The relationship between pancreas weight and body weight and islet mass in relation to body weight were calculated. Sections stained with aldehyde-fuchsin (Gomori, 1950), Mallory's phosphotungstic acid haemotoxylin and modified Davenport's technique (Epple, 1967) were prepared. Using a Wild-M501 semiautomatic sampling microscope and a Weibel graticule (Weibel et al., 1966) the percentage volume of β cells, α cells and δ cells were estimated respectively in the head, neck, body and tail regions of the six samples. The α cells or glucagon-producing cells were the most predominant as these macropodid marsupials are well adapted to dealing with hypoglycemic conditions. They were uniformly distributed in all regions.     

Biosynthesis of hexamannophosphoinositides inMycobacterium smegmatis ATCC 607

The biosynthesis of hexamannophosphoinositides inMycobacterium smegmatis ATCC 607 was examined using labelled tri- and tetraacylated dimannophosphoinositides (PIM₂-3F and PIM₂-4F) as precursors, byin vivo andin vitro incorporation. Tetraacylated dimannoside was metabolically more active as compared to triacylated dimannoside and seems to be the precursor for the synthesis of hexamannophosphoinositides.Abbreviations M. 607 Mycobacterium smegmatis ATCC 607 - PIMs Mannophosphoinositides - PIM₂-2F diacylated dimannoside - PIM₂-3F triacylated dimannoside - PIM₂-4F tetraacylated dimannoside - PIM₃-3F triacylated trimannoside - PIM₆-3F triacylated hexamannoside - PIM₆-4F tetraacylated hexamannoside - GDP-mannose Guanosine diphosphomannose     

Isolation and characterization of cDNAs encoding beta A2- and beta A4-crystallins: heterologous interactions in the predicted beta A4-beta B2 heterodimer

Except for the two acidic chains, beta A2 and beta A4, the primary structures of all bovine beta-crystallins have previously been elucidated, either by direct protein sequencing or prediction from cDNA sequencing. Both beta A2 and beta A4 were found to be synthesized in half-year-old calf lenses and are therefore likely to be present in a cDNA bovine library constructed from mRNA isolated from lenses of that age. A large number of cDNA clones was screened with all available crystallin, actin, vimentin and lens membrane protein MP26 probes and finally with a randomly primed mRNA probe. Clones positive for the latter, but negative for known lens proteins, were isolated and sequenced. beta A2, comprising 197 aa, and beta A4, comprising 209 aa, were identified. Both proteins have a conserved two-domain structure and an N-terminal extension which is variable. A three-dimensional model of the structure of beta A4 was made based on the coordinates of one subunit from the beta B2 dimer which has recently been solved using x-ray diffraction techniques. The resulting heterodimer structure, together with the compiled bovine beta-crystallin sequences, was used to indicate those regions of the sequences which distinguish acidic from basic beta-crystallins with a view to defining structural features necessary for subunit recognition in beta-crystallin aggregates. With the aid of the present data, the complete evolutionary tree of the bovine beta-crystallin family has been constructed, which confirms the early separation of the genes encoding the three acidic and the three basic beta-crystallins.     

Proteolytic Cleavage of Type I Collagen Generates an Autoantigen in Autoimmune Uveitis

This study was initiated to induce experimental autoimmune anterior uveitis (EAAU) in Lewis rats by melanin-associated antigen (MAA; 22-kDa fragment of type I collagen α2 chain) derived from rat iris and ciliary body (CB), to localize MAA within the eye, and to investigate the possible mechanism of MAA generation in vivo. The EAAU model replicates idiopathic human anterior uveitis. Lewis rats sensitized to rat MAA developed anterior uveitis, and EAAU induced by rat MAA can be adoptively transferred to naive syngenic rats by MAA-primed T cells. Animals immunized with rat MAA developed cellular immunity to the antigen. MAA was detected only in the iris and CB of the eye. Iris and CB were the major source of matrix metalloproteinase-1 (MMP-1) in the naive eye, and ocular expression of MMP-1 was up-regulated, whereas expression of tissue inhibitor of metalloproteinase 1 decreased before the onset of EAAU. These results demonstrated that EAAU can be induced by autologous MAA. Uveitogenic antigen is present only in the iris and CB of the eye, and the imbalance between MMP-1 and tissue inhibitor of metalloproteinase 1 may play a role in the generation of MAA in vivo. Collectively, the evidence presented here suggests that MAA is an autoantigen in EAAU. These observations may extend to idiopathic human anterior uveitis and facilitate the development of antigen-specific therapy.     

Localization of caveolin 1 in aortic valve endothelial cells using antigen retrieval.

Ultrastructural analysis of aortic valve endothelial cells subjected to growth arrest revealed many vesicles defined as caveolae by the localization of caveolin. Translocation of caveolin after exposure to oxidized LDL suggests that the localization of caveolin may be a valuable tool to study models of early atherogenesis. In this study, several antigen retrieval protocols were tested in osmium-fixed and Spurr-embedded cells to determine the optimal method of antigen retrieval in our model system. SDS produced the most consistent labeling pattern. A quantitative evaluation revealed that SDS significantly increased the labeling density in Spurr-embedded cells. The labeling pattern appeared as clusters of gold particles, 15-40 nm in diameter, that were associated with membranes of a similar size which may represent the neck region of the caveolae.     

Enzymatic control of membrane lipids inMycobacterium smegmatis ATCC 607 grown at low temperature

Enzymes of phospholipid synthesis were studied inMycobacterium smegmatis ATCC 607 grown at 37 and 27°C. The synthesis seemed to be regulated, at least partly, at the phosphatidic acid level by the specificity of the acyltransferases. The individual phospholipid species were found to be regulated at the enzymatic level in the maintenance of membrane fluidity.     

Human chromosomal heteromorphisms in Delhi newborns. II. Analysis of C-band size heteromorphisms in chromosomes 1, 9 and 16

Quantitative analysis of C-band size heteromorphisms in chromosomes 1,9 and 16 was carried out in 200 Delhi newborns (100 males and 100 females). The percent size heteromorphisms for chromosomes 1,9 and 16 showed nonsignificant differences between the sexes. Homozygous size level combinations showed higher incidence than the heterozygous combinations for all the three chromosome pairs studied in both sexes. Our results are compared with other reported studies and the possible role of these heteromorphisms in ethnic/racial variation and in developmental disturbances is discussed.