Altered fatty acid composition in regulatory mutants of Streptomyces cinnamonensis

Abstract cDNA-RNA liquid hybridization analysis was used to compare the RNA sequence homology between two members of the Nudaurelia β virus family, Trichoplusia ni virus ( T.ni V) and Dasychira pudibunda virus ( D.p V). Heterologous hybridization experiments demonstrated that these viruses shared little sequence homology. Using oligo(dT) chromatography and oligo(dT)_12–18 as a primer for cDNA synthesis it was shown that neither T.ni V nor D.p V RNA genomes possess a poly(A) tract at the 3' end.     

Analysis of a common inheritable idiotype in IgA-deficient sera using monoclonal antibodies

In these studies we describe the production of three mAb raised to an idiotype on an IgG anticasein antibody isolated from the serum of one IgA-deficient blood donor. These are IgM kappa and block the binding of casein Ag to anticasein antibody. Sera of unrelated IgA-deficient donors were tested for the presence of the idiotype; 15 of 56 IgA-deficient sera (25%) contain the anticasein idiotype, whereas 1 of 45 normal sera was positive. Anticasein antibodies as a whole were predominantly of the IgG1 and IgG3 subclass; idiotype-positive anticaseins are predominantly of the IgG1 subclass. For IgA-deficient donors, the relative amount of idiotype-positive anticasein antibody was correlated with the level of anticasein present in the serum. Studies were done to investigate the potential inheritance of the idiotype in families; in three of four families the idiotype was inherited in an apparent autosomal dominant pattern. Our data show that a common cross-reactive idiotype can be detected in the sera of IgA-deficient individuals and their family members. This suggests that V region markers may be conserved in this humoral immunodeficiency disease.     

Azide-resistant mutants in Acinetobacter calcoaceticus A2 are defective in protein secretion

Abstract Azide, an inhibitor of ATPase, and a specific inhibitor of protein export was used in order to select for protein secretion mutants in Acinetobacter calcoaceticus A2. Two such mutants were isolated that were azide-resistant and defective in the general protein transport system. The mutation also conferred additional phenotypic changes, including an inability to grow on minimal media or at 40°C. The existence of protein secretion mutants with a selectable phenotype may be useful for the genetic study of protein export.     

Method for isolating single cardiac cells in the guinea pig using pronase. The role of calcium ions

A method for isolation of guinea-pig cardiomyocytes with pronase has been developed. The method has been assessed in hearts perfused with solutions containing pronase (1 U/ml) and 200 microM Ca2+. Eighty per cent of the cells released were rod-shaped and 1.2 mM Ca2+ tolerant. Enriched medium 199 was used for all solutions. Sodium and slow inward currents recorded from cells dispersed with pronase were similar to those recorded from cells isolated after prolonged exposure to collagenase. Two principal factors are to be marked: (a) presence of high enough amounts of Ca2+ in enzyme solution (up to 200 microM); (b) use of the enriched medium in all the stages of the procedure.     

The diagnosis of antileptospiral antibodies in human subjects by solid-phase immunoenzyme analysis

The possibility of using the enzyme-linked immunosorbent assay (ELISA) for the diagnosis of leptospirosis has been shown. This method has proved to be more simple and sensitive than the leptospiral microagglutination and lysis test. The data on obtaining genus-specific leptospiral antigens are presented. As revealed in this study, the antigens obtained by the complex treatment of microbial cells with ultrasound and detergents show the maximum activity in ELISA. The optimum parameters of the ELISA system for the diagnosis of leptospirosis have been established.