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.     

Comparative study of histones from slime mold Physarum polycephalum and calf thymus

The histones from slime mold Physarum polycephalum and calf thymus were characterized in terms of some physico-chemical properties. The molecular weights of six principal histone fractions of Ph. polycephalum were found to be the following: P1--22 700, P3--15 700, P4a--15 000, P4b--14 300, P5--12 800 and P6--10 500. Electrophoretically homogenous histone fractions H1, H2b and H4 of calf thymus and histones P1, P3, P4b and P6 of slime mold were obtained by gel-filtration on Acrylex P-60. These findings suggest that fractions P1, P4a, P4b, P5 and P6 of slime mold Ph. polycephalum are homologus with respect to the histone fractions H1, H3, H2b, H2a and H4 of calf thymus. Only fraction P3 has no corresponding fraction in the calf thymus histones; a fraction corresponding to histone P3 of slime mold was absent.     

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.