Effect of ethanol on hepatic ribosomal proteins and mRNA

Levels of RNA, mRNA and separation of ribosomal proteins from control and ethanol treated rat liver, showed no change in total RNA content, but poly(A⁺)mRNA was reduced significantly in ethanolic rats. Ribosomal proteins S2, S3a, S3b, S4, L3, L4, L4a, L10a and L15 were found substantially reduced in experimental rat livers. This study suggests decrease in poly(A⁺) mRNA coupled with loss of ribosomal proteins must be responsible for decreased protein synthesis in chronic alcoholism.     

Variations in the pathways of malate oxidation and phosphorylation in different species of Mycobacteria.

Mycobacterium tuberculosis H37Rv, the slow-growing human pathogenic strain of tubercle bacilli and Mycobacterium smegmatis and Mycobacterium phlei, the fast-growing saprophytes, have shown variations regarding the type of dehydrogenase that initiates malate oxidation in the respiratory chain. M. tuberculosis H37Rv is characterized by having a malate oxidase system (designated MALNAD pathway) in which malate oxidation is mediated by the NAD+-dependent malate dehydrogenase (EC 1.1.1.37) but not by FAD-dependent malate-vitamin K reductase. M. smegmatis possesses a different malate oxidase system (designated MALFAD pathway) in which malate oxidation is exclusively carried out by the FAD-dependent malate-vitamin K reductase because NAD+-dependent malate dehydrogenase is absent in this organism. M. phlei has a mixed system of malate oxidase (designated MALNAD+FAD pathways) in which both the NAD+-and FAD-dependent dehydrogenases take part. In all the three systems, the rest of the electron transport chain is common.     

Pathways of carbohydrate metabolism in mycobacterium tuberculosis H37Rv1.

Radiorespirometric studies using glucose labelled at 1, 2, 3-4, and 6 positions and enzymatic studies were conducted to determine the primary pathways of glucose dissimilation in Mycobacterium tuberculosis H37Rv. The pattern of 14CO2 recovery was C3-4 greater than C1 greater than C6 = C2. The Embden-Meyerhof pathway was found to be the predominant pathway for glucose oxidation, operative to the extent of 94%. The pentose phosphate pathway accounted for the remaining 6%. Maximum incorporation of 14C into cellular components was from C2 and C6 labelled glucose.     

Specific association of two homologous DNA-binding proteins to the native 30-S ribosomal subunits of Escherichia coli.

The native 30-S ribosomal subunits from Escherichia coli are shown to be associated with two proteins which are different from the known ribosome-associated and ribosomal proteins. Neither protein is foune on native 50-S subunits or on intact ribosomes in the cell extract. The purified proteins re-bind in vitro to free 30-S subunits, but do not bind to either free 50-S subunits or intact ribosomes. The proteins, denoted NS1 and NS2, have been purified and characterized. Both proteins showed the same molecular weight of 9500 by sodium dodecyl sulfate gel electrophoresis but 34 000 by gel filtration. Upon treatment with cross-linking reagents the purified proteins gave higher molecular weight species up to the tetrameric ones showing that they exist in solution as tetramers. The amino acid compositions, tryptic fingerprint patterns and N-terminal sequences of the two proteins have been determined. These data show that NS1 and NS2 possess distinct primary structures but with extensive sequence homology. Antibodies raised against the purified proteins cross-reacted in double immuno-diffusion tests confirming further the homology. Because of the similarity in properties a sample of the DNA-binding protein HD (Berthold, V. and Geider, K. (1976) Eur. J. Biochem. 71, 443--449) was compared to NS1 and NS2. In terms of several criteria, the protein HD is found to be a mixture of two proteins, namely NS1 and NS2. The present report is the first instance of an association of DNA-binding proteins to the ribosome.     

Structural and conformational changes concomitant with the E1-E2 transition in H(+)K(+)-ATPase: a comparative protein modeling study

Comparative modeling studies on conserved regions of the gastric H(+)K(+)-ATPase reveal that the E1-E2 conformational transition induces significant tertiary structural changes while conserving the secondary structure. The residues 516-530 of the cytoplasmic domain and TM10 within the transmembrane (TM) regions undergo maximum tertiary structural changes. The luminal regions exhibit comparatively lesser tertiary structural deviations. Residues 249-304 show maximum secondary structural deviation in the conformational transition. The Cys-815 and Cys-323 residues involved in inhibitor binding are found to have smaller buried side chain areas in the E1 conformation compared to E2. Retention of activity correlates well with the buried side chain area when selected amino acid residues in TM6 are mutated using modeling techniques with bulkier amino acid residues. Conformational specificity for ion binding is corroborated with the fraction of side chains exposed to polar atoms of the residues E345, D826, V340, A341, V343, and E822.     

Management of filariasis using prediction rules derived from data mining

The present paper demonstrates the application of CART (classification and regression trees) to control a mosquito vector (Culex quinquefasciatus) for bancroftian filariasis in India. The database on filariasis and a commercially available software CART (Salford systems Inc. USA) were used in this study. Baseline entomological data related to bancroftian filariasis was utilized for deriving prediction rules. The data was categorized into three different aspects, namely (1) mosquito abundance, (2) meteorological and (3) socio-economic details. This data was taken from a database developed for a project entitled "Database management system for the control of bancroftian filariasis" sponsored by Ministry of Communication and Information Technology (MC&IT), Government of India, New Delhi. Predictor variables (maximum temperature, minimum temperature, rain fall, relative humidity, wind speed, house type) were ranked by CART according to their influence on the target variable (month). The approach is useful for forecasting vector (mosquito) densities in forthcoming seasons.     

A web based relational database management system for filariasis control

The present study describes a RDBMS (relational database management system) for the effective management of Filariasis, a vector borne disease. Filariasis infects 120 million people from 83 countries. The possible re-emergence of the disease and the complexity of existing control programs warrant the development of new strategies. A database containing comprehensive data associated with filariasis finds utility in disease control. We have developed a database containing information on the socio-economic status of patients, mosquito collection procedures, mosquito dissection data, filariasis survey report and mass blood data. The database can be searched using a user friendly web interface.

Availability     

The Effect of Gibberellin on Tryptophan Conversion and Elongation of the Avena Coleoptile

Gibberellic acid (GA₃) enhanced directly the release of ¹⁴CO₂ from tryptophan-1-^l4C by cell free preparations of Avena coleoptile tips. The rate of tryptophan metabolism in the presence of GA₃ was increased by approximately 100 per cent. The addition of auxin synthesis inhibitors to incubation flasks nullified the enhancement effect of GA₃ on elongation of the coleoptile tips. These studies implicate tryptamine as an intermediate in the formation of auxin from tryptophan. The possibility of GA₃-IAA interaction in the elongation processes was also investigated. Combination treatments of these growth-promoting substances did not induce a synergistic growth response by the coleoptile tissue.     

Hexokinase activity as marker to assess time of harvest of foot-and-mouth disease virus in BHK21 Cl13 cell cultures

Hexokinase (B.C. 2.7.1.1) activity as a marker enzyme during FMD viral infection has been observed spectrophotometrically in a system coupled with glucose-6-phosphate dehydrogenase, in supernatants of BHK(21)Cl(13) suspension as well as anchored cell culture at a minimum of 10(4) infective virus particles/ml. Specific activity increased with virus concentration in culture supernatants and abruptly decreased with a fall in virus titer, as has been noted by TCID/50,146 S concentration, and enzyme-linked immunosorbent assay (ELISA) readings.