Glycosaminoglycan (GAG) level and activities of certain enzymes of GAG metabolism in Culex quinquefasciatus and Setaria digitata

Significant differences were observed in GAG metabolism of S. digitata and one of its intermediate vectors, C. quinquefasciatus. Distribution of different components such as hyaluronic acid, heparin-sulphate, chondroitin-4-sulphate, chondroitin-6-sulphate, dermatan sulphate and heparin was comparable in both. However, there were quantitative differences; the difference was marked in the activity of enzymes of GAG metabolism in presence and absence of diethylcarbamazine (DEC) a known antifilarial drug. While the activities of beta-galactosidase and beta-N-acetyl glucosaminidase of S. digitata systems showed an inhibition of 96.5 and 92.6% respectively, in the Culex systems they showed an inhibition of 93.3% and an activation of 18% respectively. The differences clearly indicate the existence of basic differences in GAG metabolism of vector and parasite.     

Clinical and experimental mycotic keratitis caused by Aspergillus terreus and the effect of subconjunctival oxiconazole treatment in the animal model

Aspergillus terreus was isolated from a case of Keratomycosis. The patient, a 50 year old, female presented with a large corneal ulcer with hypopyon. The direct microscopic examination of the scrapings revealed hyaline, thin, septate and branched hyphae. In vitro some antimycotics (amphotericin B,5-fluorocytosine, oxiconazole, amorolfine and ketoconazole) were tested against A. terreus by agar dilution method. Ketoconazole with MIC of 3 gmg/ml after 7 days of incubation was most effective followed by oxiconazole (10g/ml). Experimental corneal ulcer was produced by injecting intralamellary 0.1 ml of the spore suspension containing 10×10₆ cfu/ml into the eyes of previously immunocompressed albino rabbits. Histopathologic examination showed infiltration and large destruction of the corneal stroma. Subconjunctival oxiconazole therapy exhibited complete cure. Based on our findings, a clinical evaluation of oxiconazole in human keratomycosis seems to be justified.     

Genetic evidence for α2-adrenergic receptor subtypes in rat brain,heart and adrenal gland

Summary A complementary DNA (cDNA) clone - cA₂-47 - corresponding to a new ₂-adrenergic receptor subtype has been isolated from a rat brain cDNA library and used as a hybridization probe to scrutinize the ₂-receptor poly(A⁺) RNAs in rat brain, heart and adrenal gland. Hybridization of the 5 half of the coding region of this cDNA at 37°C to rat brain poly(A+) RNA revealed a single band at 5.8 kb as the size of its corresponding mRNA. Under identical hybridization conditions, a human platelet ₂-receptor genomic probe failed to hybridize to any rat brain mRNAs.Under lower stringency conditions, hybridization of the full-length cDNA, cA₂-47, to selected rat tissue poly(A⁺) RNA showed the presence of four different sized mRNAs in brain and three in both heart and adrenal gland. Messages of 1.3 kb and 2.1 kb were common in all three tissues (although the band at 2.1 kb was slightly higher in the heart and adrenal gland). A 5.8 kb mRNA was unique to the brain and a slightly higher band at 6.0 kb was consistently present in heart and adrenal gland but was absent in the brain. A fourth message at 3.4 kb was found predominantly in the brain and was either absent or present at very low levels in the other tissues examined. Under the same conditions, a human platelet ₂-receptor probe hybridized to similar sized messages of 2.1 and 5.8 kb in rat brain and 2.2 and 6.0 kb in rat heart and adrenal gland. This probe, however, failed to detect the abundant 1.3 kb mRNA common to all tissues or the 3.4 kb message in rat brain. The extent of homology of these messages with cA₂-47 is not confined to limited regions of the cDNA since similar hybridization patterns were observed using either 5-noncoding or 5-coding regions of the probe.These results provide the first direct evidence of a surprisingly large range of mRNA sizes for members of the ₂-receptor family in brain, heart, and adrenal gland. The unique nature of certain members of the family in each of the tissues examined raises the curious possibility that these members might contribute to some of the individualized functions of the brain, cardiovasculature and adrenal gland.     

Search for chromosomal variations among gas-exposed persons in Bhopal

Summary A chromosomal survey using standard lymphocyte cultures employing different media and G-banding techniques was initiated in 1984. This study became particularly important following the tragic gaseous exposure of the population in Bhopal at midnight on 2 December 1984. We have been able to formulate a chromosomal profile for each person whom we have studied; during 1986–1988, 154 persons were examined twice. Among seemingly normal individuals, as many as 20% might possess some chromosomal abnormality; of these, 50% may develop, at a later date, some kind of pathological complication (such as tumours, recurrent abortion or transmission of defects to their offspring). The people exposed to methyl isocyanate have repeatedly shown Robertsonian translocations, mostly in acrocentric chromosomes 13 and 21. Other types of translocations have been studied among all exposed (53) and normal (101) persons; the involvement of chromosomes 5, 9, 11, 14 and 16 is statistically significant (P= <0.001). One of the major clinical symptoms is dyspnoea; we have estimated that almost all seriously dyspnoeic patients have developed at least two categories of chromosomal aberrations, one of which is Robertsonian translocation, in at least 10% metaphases. Our chromosomal survey will be of significance because we are able to identify people with chromosomal aberrations that might be correlated with future pathological consequences of the accident. The chromosomal load that can be sustained with an apparently normal phenotype can also be measured.     

Degradation of synthetic lignins and some lignin monomers by the yeastRhodotorula glutinis

Rhodotorula glutinis degraded variously¹⁴C-labelled synthetic lignins in the presence of 0.1% glucose as co-substrate. Side chain-labelled DHP was degraded the most. While this yeastutilized vanillate and forulate for growth, sinapate/syringate were poorly or not degraded. Gallate, protocatechuate and acetate also supported growth. [carboxy-¹⁴C]Syringate was rapidly converted to¹⁴CO₂ by the yeast only in presence of glucose while [carboxy-¹⁴C]vanillate did not require any additional cosubstrate for mineralization. Ring-labelled vanillyl alcohol was also dagraded proving that the yeast could rapidly metabolize guaiacyl structures while syringyl structures required the presence of additional energy sources.

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Résumé Rhodotorula glutinis dégrade des lignines synthétiques marquées au¹⁴C de manière variée, en présence de 0.1% de glucose comme co-substrat. La DHP marquée sur la chaîne latérale est dégradée le plus. Alors que cette levure utilise le vanillate et le férulate pour sa croissance, le sinapate et le syringate sont peu ou prou dégradables. Le gallate, le protocatéchuate et l'acétate supportent également la croissance. Le syringate marqué au¹⁴C dans sa fonctioncarboxyle estrapidement convert en¹⁴CO₂ par le levure mais exclusivement en présence de glucose, tandis que le vanillate marqué au¹⁴C dans sa fonction carboxyle ne requiert aucun co-substrat additionel pour sa minéralisation. L'alcool vanillique marqué dans son cycle, est également dégradé démonstrant ainsi que la levure peut métaboliser rapidement des structures guaiacyliques tandis que les structures syringiques requièrent la présence de sources auxiliaires d'énergie.

     

Lectin mediated agglutination of Candida kefyr cells and their spheroplasts grown in sterol enriched growth medium and its correlation with lipid composition

Supplementation of the growth medium with erosterol, cholesterol and lanosterol enriched the Candida kefyr cells, presumably cell membranes with sterols. Sterol enriched C. kefyr cells showed a decrease in percentage of PHA and Con-A mediated agglutination. Sterol supplementation also increased the sterol: phospholipid ratio and in such cells unsaturated fatty acids predominated over saturated ones. The overall effect of these changes resulted in rigidifying the cell membranes as indicated by shift of break in Arrhenius plots of Mg2+ ATPase. This showed that lectin mediated agglutination of yeast cells may be affected by its membrane fluidity.     

Rapid production of ethanol in high concentration by immobilized cells of Saccharomyces cerevisiae through soya flour supplementation

Summary Ethanol concentration and fermentation productivities were substantially increased when soya extract was added to the fermentation medium using immobilized cells of a locally isolated strain of S. cerevisiae. Very high concentrations, 152 and 162 g/l of ethanol, were obtained from a medium containing 300 and 350 g/l sugars respectively by supplementing the medium with soya extract. The fermentation time was also reduced by more than 50%.     

Calcium and abnormal reactivity of vascular smooth muscle in hypertension

It has been well documented that vascular smooth muscle (VSM) reactivity, as well as calcium sensitivity in response to neurotransmitters is increased in a number of blood vessels in established hypertension. Regulation of VSM reactivity involves the interaction of neurotransmitters and blood-borne hormones with specific receptors on target cell membranes. This results in phospholipase-C-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) and the generation of two second messengers: inositol 1,4,5 trisphosphate (IP3) and diacylglycerol (DAG) both of which act synergistically to produce muscle contraction. We will summarize recent findings in this review which suggest that in essentially hypertensive patients and spontaneously hypertensive rats (SHR), the activation of phospholipase C in response to hormones is increased. Further, we will discuss how increases in phospholipase C activation via GTP-binding proteins may explain the observed increases in Ca2+ influx through potential- and receptor-operated Ca2+ channels, increased activation of protein kinase-C and increased [Ca2+]i in hormone-stimulated blood platelets and VSM cells in the hypertensive state. In addition to these defects, a decrease in the plasma membrane Ca2+ pump and Ca2+-binding proteins has been demonstrated in hypertension. Thus, it appears that the defect in Ca2+ metabolism in the hypertensive vessels is multifocal. All these defects in Ca2+ metabolism together may lead to an increase in peripheral vascular resistance with a concomitant increase in blood pressure.