- Volume 69, Issue 1, 1971

Summary: When crude membrane preparations from broth-grown Bacillus subtilis (atcc 9372) were incubated with 20 p.p.m. technical chlordane inhibition of NADH oxidase reached 45% in only 3 min. and 75% after 1 h. Maximum inhibition was obtained at this concentration of chlordane. NADH: acceptor oxidoreductase (EC 1.6.99.-) of membrane preparations was insensitive to 20 p.p.m. chlordane. Disruption of the remainder of the electron-transport chain appeared to be general though more severe in the region between NADH dehydrogenase and cytochrome c. A generalized assay for ATPases revealed no sensitivity to chlordane over a concentration range 20 to 100 p.p.m. and a pre-incubation period of 1 h. The inhibition of TCA cycle enzymes observed, subsequent to the incubation of high-speed supernatant fluid with 20 p.p.m. chlordane, extended the range of chlordane-sensitive phenomena to enzymes other than those that are membrane bound.

SUMMARY: Escherichia coli b organisms recovered from aerosols had a changed envelope as manifested by the bacteria becoming sensitive to lysozyme. Certain di- and trivalent cations added to suspensions of bacteria recovered from aerosols mitigated this sensitivity. Repair required a carbon-energy source, but not synthesis of protein, ribonucleic acid or mucopeptide. Components of the envelope were released from the aerosolized organisms. These results support the hypothesis that aerosolization caused changes in the outer wall structure of bacteria that resemble changes induced by ethylenediaminetetraacetic acid.

Summary: Conjugation in Vibrio cholerae is mediated by a sex factor, designated the P factor. The present report is concerned with the identification of another transmissible factor, labelled the V factor, in a strain of non-cholera vibrio. Although the P and V factors are compatible and may coexist in a cell, a phenomenon of repression of P is observed in the presence of the V factor. There is, however, a brief time lag during which P− V+ cells, newly infected with the P factor, are fertile. The evidence points to the development of a repression mechanism after infection with the P factor in these strains. Rare recombinants having the O antigens of the non-cholera vibrio strain (donor) were isolated from a strain of V. cholerae (recipient) after conjugation. One such recombinant was P+V− and could therefore be used to obtain similar antigenic hybrids from other strains of V. cholerae.

SUMMARY: Transient (T) forms of Salmonella resemble both virulent smooth (S) and avirulent rough (R) forms. We studied the effect of the Ti antigen on mouse virulence by introducing the rft+ gene, which determines the synthesis of Ti- specific structures, into S and R forms. The Ti antigen slightly increased the very low virulence of the R forms. When present together with the O antigen in Ti, S hybrid forms the Ti antigen had the opposite effect: it reduced the virulence of the S form considerably. This effect was probably due to the concomitant reduction in the amount of O antigen.

Summary: The growth of a range of Gram-positive bacteria was inhibited by organochlorine insecticides while that of Gram-negative organisms was unaffected. Growing cultures of Bacillus subtilis (atcc9372) treated with 20 p.p.m. technical chlordane ceased to grow and showed a decline in viable count and respiration rate, both being eliminated after about 3 h. A delayed release of incorporated l-[U-14C]leucine and l-malate dehydrogenase occurred concomitant with a fall of E 580. It is suggested that these phenomena are a result of disruption of membrane- associated metabolism, including electron transport and cell wall biosynthesis, which leads to cell lysis. No effect on these parameters occurred with growing cultures of Escherichia coli (atcc8739). The chlordane sensitivity of succinate oxidation by sphaeroplasts of E. coli indicates that the intact cell wall prevents penetration of pesticide to sensitive sites within the walls of Gram-negative bacteria.

Summary: A collection of 283 nocardioform bacteria was studied by means of 241 tests which included many biochemical, physiological and nutritional characters. The results were subjected to computer analysis in which two coefficients of association and two cluster-analysis techniques were used. Single linkage and average linkage cluster analysis gave almost identical results, but with the simple matching coefficient a few strains were grouped together on the basis of shared negative correlations. With the matching coefficient 15 clusters were formed whereas with the similarity coefficient there were 18. In each analysis the seven major clusters corresponded to (1) Nocardia asteroides, (2) Nocardia caviae, (3) Nocardia brasiliensis, (4) Actinomadura madurae, (5) Actinomadura pe lie fieri, (6) Oerskovia turbata, (7) the rhodochrous complex. The data revealed many new characters which could be weighted for identification. The clusters and subgroups were therefore readily distinguished from one another by several unrelated phenotypic characters.