Immunogenesis and axoplasmic transport in Wistar rats]

Immunization of Wistar rats with thymus dependent antigens (sheep red blood cells-SRBC) is accompanied by a reliable increase in the synthesis of RNA and proteins in thalamic cerebral cortex and spinal marrow (48 hrs after antigen injection) and also in an increase in the intensity of rapid axoplasmic transport (RAT) along motor fibers of sciatic nerve (5,48,72 hrs following the beginning of immunization). There was a consecutive augmentation in AFC number in mesenteric and partly in inguinal lymph nodes (96 hrs after SRBC injection). Thus, time dependence between immunogenesis and axoplasmic transport in experimental animals (Wistar rats) was determined for the first time. It identifies another, previously unstudied, channel in interactions of immune and nervous systems.     

The identification of the membrane proteins of human and animal viruses]

The review deals with the methods of identification of virus-specific proteins on virion and infected cell surface. The isotopic labeling of membrane proteins, their extraction by proteolytic enzymes and selective solubilization by detergents are considered. The plasmatic membrane isolation by centrifugation and by means of microcarriers is described. The methods of membrane protein localization using monoclonal antibodies and radioimmunoprecipitation are presented.     

Interactions among cytochromes P-450 in the endoplasmic reticulum. Detection of chemically cross-linked complexes with monoclonal antibodies

The quaternary structure of rat liver cytochrome P-450 within microsomal membranes from 3-methyl-cholanthrene-treated rats was examined by a novel chemical cross-linking-monoclonal antibody approach. Complex formation among the different forms of P-450 was probed by cross-linking of membrane proteins followed by immunopurification with a monoclonal antibody (mAb) to P-450c, the major 3-methylcholanthrene-inducible form. Subsequent immunoblot analysis of the immunopurified proteins with this mAb indicated that P-450c formed complexes with other microsomal proteins. Immunoblots with mAbs to different P-450s were carried out to identify the P-450s that were cross-linked to P-450c. This approach detected specific cross-linking of P-450c to P-450 2a. Immunoinhibition experiments suggest that P-450 2a further metabolizes the primary phenols produced by P-450c-catalyzed hydroxylation of benzo[a]pyrene. Complex formation among membrane-bound enzymes has implications for their catalytic efficiency and an approach combining cross-linking and monoclonal antibody-based characterization of cross-linked proteins will be useful for elucidating such membrane protein macrostructures.     

Evaporative temperature and moisture control in a rocking reactor for solid substrate fermentation

Summary In the solid substrate fermentation of cooked yellow corn grits with Rhizopus oligosporus in a rocking drum fermenter, temperature was controlled by blowing air through the substrate, forcing water evaporation. The rate of evaporation was controlled by the relative humidity of the air, according to the rate of heat generation during fermentation. Moisture content was maintained constant by spraying cold water on the substrate regulated by the water balance equation of the system. Both controls were operated by computer programs. The rocking motion in the reactor allowed even distribution of air and water in the substrate without disturbing the growing mycelia.     

Occurrence of grapevine chrome mosaic nepovirus in Austria

A virus recovered by inoculation of sap from Austrian vines with yellow mosaic symptoms was compared with, and found virtually indistinguishable from, an authentic Hungarian isolate of grapevine chrome mosaic nepovirus. This seems to be the first record of the virus in Austria.     

Immobilization of urease on gelatin — poly (HEMA) copolymer preparation and characterization

Urease was immobilized onto gelatin-poly (HEMA) copolymer by covalent linkage. Maximum amount of urease was immobilized onto the support at a pH of 8.5. The optimal pH of the immobilized urease was similar to that of free urease; the optimal temperature showed an increase of 10 °C over the free enzyme. The stability of the immobilized urease for a range of pH, temperature and shelf life was greater than the corresponding values for the free enzyme. The same result was obtained for k _m also.Grateful acknowledgement is made to CSIR, Govt. of India for the research associateship conferred on Dr. M. Chellapandian which helped the progress of this piece of research investigation.     

Spatial pattern analysis of the incidence of aster yellows disease in lettuce

The degree of aggregation of lettuce plants infected by aster yellows phytoplasma (AYP) was investigated in 12 fields from three experiments. Position of diseased and healthy plants was mapped in a 6–9×12-m section of each field; for most analyses, fields were divided into 10-plant quadrats. Mean disease incidence (p) ranged from 0.01 to 0.30. The frequency of diseased plants was described by the beta-binomial distribution, with an index of aggregation (θ) ranging from 0 to 0.17, positively correlated withp, and generally increasing over time within a field. Distance-class analysis revealed a core-cluster size of only a few plants. However, spatial autocorrelations ofp between quadrats were not significant, indicating that the scale of spatial pattern was small, generally less than 10 plants. An overall measure of aggregation was given by the slope parameter of the binary form of the power law, in which the log of the calculated variance is regressed on the log of the theoretical variance for a binomial distribution. The slope was 1.18 and significantly different from 1. Results for this “simple-interest” disease are interpreted in relation to the persistent transmission of AYP by its aster leafhopper vector.     

Inhibition of acid production in Streptococcus mutans R9: Inhibition constants and reversibility

Abstract The pac gene encoding the penicillin G acylase (PGA) of Bacillus megaterium ATCC 14945 has been cloned in Escherichia coli HB101 ( proA, leuB ) using a selective minimal medium containing phenylacetyl-L-leucine instead of L-leucine. The nucleotide sequence of this gene has been determined and contains an open reading frame of 2406 nucleotides. The deduced amino acid sequence shows significant similarity with other β-lactam acylases. Although the PGA of B. megaterium is extracellular, the enzyme produced in E. coli appears to have a cytoplasmic localization.