Strictly aerobic, non-motile, gram-negative coccobacilli were isolated from the seawater of Otsuchi Bay, Japan, and the Indian Ocean. They were divided into group 1, group 2 and others on the basis of morphological, physiological and chemotaxonomic characteristics. The members of group 1 were classified as a separate genus closely related to the genera Acinetobacter and Moraxella. The members of group 2 were assigned to the genus Moraxella. However four strains of group 2 were psychrotrophic, so we call them tentatively "psychrotrophic Moraxella." In the other isolates, the taxonomic positions of seven strains, having G+C contents of 50.5% to 61.8%, were unclear. Also one strain was recognized as closely related but different from the genera Acinetobacter and Moraxella. And one strain was identified as Acinetobacter lwoffii (Audureau 1940) Brisou and Prévot 1954. All but two of the isolates were moderately halophilic.
We have prepared three kinds of plasmids containing two lactose promoters in palindromic positions. In the first, structure I, the promoters are joined tail to tail and transcription proceeds from head to tail. In structure II they are joined head to head. In structure III a foreign DNA is located between the two lactose promoters. The plasmid of structure I can not multiply in wild-type Escherichia coli but can in E. coli recB recC sbcBrecF. Since a plasmid with structure III can grow in the wild-type strain, a linear DNA fragment which is prepared from structure III by removing the foreign DNA can be used as a very efficient cloning vector. Plasmid DNA with structures I and II isolated from E. coli recB recC sbcBrecF were shown to have a relaxed form by agarose gel electrophoresis. However, in contrast to the structure I plasmid, structure II plasmid can multiply in wild-type cells, though it is unstable and present in a low copy number. Excised head to head dimer, but not tail to tail dimer, moved at an unusual rate in polyacrylamide gel electrophoresis. The difference between the physical structures of the two dimers of the lactose promoter may be reflected in the biological character of the plasmids.
As an aid to a more rational classification of small Bacillus phages that contain DNA with terminal protein, we have compared genome size, physical maps, and electrophoretic patterns of the structural proteins of five bacteriophages (φ29, φ15, Nf, M2Y and GA-1). In addition, we compared tryptic and chymotryptic peptides of the major structural protein of these phages. The results allow the following conclusions. Five small phages can be classified into three groups: group A (φ29 and φ15), group B (Nf and M2Y) and group C (GA-1). The peptide maps of the major head protein of M2Y and Nf are very similar. On the other hand, the peptide maps of the GA-1 major head protein are not related to those of the other phages. Our present results suggest that although physical maps are quite different in group A and group B phages, the overall gene organization is similar in the two groups. On the other hand, group C phage, GA-1, is considerably different from the other two groups. These results argue that GA-1 phage have diverged very markedly from a common ancestor or were generated through a different evolutionary pathway.
The effect of 3-amino-1, 2, 4-triazole (amitrol), an uncoupler of the Q of photosystem II, on growth, heterocyst frequency, H2 production, acetylene reduction (nitrogenase activity) and photosynthetic O2 evolution was studied in Nostoc linckia. Whereas amitrol inhibited growth, acetylene reduction and O2 evolution, it increased heterocyst frequency and H2 production. Exposure of Nostoc linckia to higher concentrations of amitrol caused pronounced fragmentation of filaments into 5- to 10-celled trichomes. The observed effects on growth and other physiological processes may be due to the reduction in reluctant and ATP pool(s).
Flora of lactic acid bacteria in five Miang samples, fermented tea leaves on northern Thailand, was studied quantitatively and qualitatively. Lactic acid bacteria (103 to 105per gram) were found in four samples, and none in one sample. The latter sample may have been greatly affected by the production of acid during the long fermentation. The ten representative isolates were characterized by their morphological, physiological, and chemical properties. All of these isolates were identified as Lactobacillusplantarum (Olra-Jensen) Bergey et al., with diaminopimelic acid (A2pm) peptidoglycan in the cell wall. Apparently the tea tannic acid in the Miang selected only the L. plantarum with A2pm peptidoglycan in the cell wall. This is interesting in view of the bacterial flora formation involved in Miang fermentation.
A series of single copy promoter-probe vectors for Bacillus subtilis was constructed from phage φ105 by introducing a promoterless amylase gene. With these vectors, strong promoters were cloned from Bacillus licheniformis chromosomal DNA. In addition, the transcriptional direction of the kan of pUB110 was determined using the DNA fragments within these phages as promoter-probe cartridges.
The gene cloning system in Bacillus subtilis, using temperate phage φ105 (prophage transformation), was improved by introducing a chloramphenicol resistance (Cmr) marker into the vector phage DNA to facilitate the primary selection of transformants. Two vector phages, φCM and φCL, were constructed; the former has BamHI and BglII sites for cloning and the latter BglII and ClaI sites. Another improvement was increasing the transformation efficiency of the φ105 lysogen about tenfold by using a non-inducible mutant of φ105, φ105ind-1, as prophage. When the α- amylase gene previously cloned from Bacillus amyloliquefaciens was transferred with the new vector-prophage system, α-amylase-producing clones were isolated at a frequency of about 10% of the Cmr transformants. When the transformants were non-inducible, the induction- negative prophages could be made induction-positive by repeating the transformation using the recipient lysogen harboring wild type φ105 prophage.