Construction of a Contiguous 874-kb Sequence of the Escherichia coli-K12 Genome Corresponding to 50.0-68.8 min on the Linkage Map and Analysis of Its Sequence Features

The contiguous 874.423 base pair sequence corresponding to the50.0–68.8 min region on the genetic map of the Escherichiacoli K-12 (W3110) was constructed by the determination of DNAsequences in the 50.0–57.9 min region (360 kb) and twolarge (100 kb in all) and five short gaps in the 57.9–68.8min region whose sequences had been registered in the DNA databases.We analyzed its sequence features and found that this regioncontained at least 894 potential open reading frames (ORFs),of which 346 (38.7%) were previously reported, 158 (17.7%) werehomologous to other known genes, 232 (26.0%) were identicalor similar to hypothetical genes registered in databases, andthe remaining 158 (17.7%) showed no significant similarity toany other genes. A homology search of the ORFs also identifiedseveral new gene clusters. Those include two clusters of fimbrialgenes, a gene cluster of three genes encoding homologues ofthe human long chain fatty acid degradation enzyme complex inthe mitochondrial membrane, a cluster of at least nine genesinvolved in the utilization of ethanolamine, a cluster of thesecondary set of 11 hyc genes participating in the formate hydrogenlyasereaction and a cluster of five genes coding for the homologuesof degradation enzymes for aromatic hydrocarbons in Pseudomonasputida. We also noted a variety of novel genes, including twoORFs, which were homologous to the putative genes encoding xanthinedehydrogenase in the fly and a protein responsible for axonalguidance and outgrowth of the rat, mouse and nematode. An isoleucinetRNA gene, designated ileY , was also newly identified at 60.0min.     

Structural analyses of DNA fragments integrated by illegitimate recombination in Schizosaccharomyces pombe

Molecular Genetics and Genomics - In order to elucidate the mechanisms of illegitimate recombination in eukaryotes, we have studied the structure of DNA fragments integrated by illegitimate...     

Natural dolapyrrolidone: Isolation and absolute stereochemistry of a substructure of bioactive peptides

During the course of our chemical analysis of the hydrophilic fractions from marine cyanobacterium Moorena producens, we have isolated natural dolapyrrolidone (Dpy, 1 ), a natural pyrrolidone derived from phenylalanine, for the first time as a single compound. Compound 1 , with an (S)-l absolute stereochemistry, was previously identified as a substructure that is common among several bioactive natural peptides. Surprisingly, the absolute stereochemistry of the isolated natural 1 , determined through total synthesis, was (R)-d . This result was unambiguously determined by HPLC analysis using a chiral stationary column by comparing the retention times of the natural 1 and authentic samples of synthetic enantiomers. To verify the unexpected result, the absolute stereochemistry of the natural 1 was confirmed by X-ray crystallographic analysis of Pt-complex derivative using the synthetic enantiomer.     

Intracellular Localization of Phosphoenolpyruvate Carboxykinase in Bundle Sheath Cells of C4 Plants

Bundle sheath protoplasts (BSP) were isolated and purified fromfour C₄ species of the phosphoenolpyruvate (PEP) carboxykinasetype (Panicum maximum, P. texanum, Chloris gayana and Eriochloaborumensis), and cell organellses were separated from the BSPextract by differential centrifugation or sucrose density gradientcentrifugation. Separation of the organelles was ascertainedby the distribution of marker enzymes for chloroplasts, mitochondria,peroxisomes and cytoplasm. Contrary to the previous report [Rathnamand Edwards (1975) Arch. Biochem. Biophys. 171: 214], the distributionof PEP carboxykinase in BSP of P. maximum was the same as thatof UDP-glucose pyrophosphorylase, a marker for cytoplasm, andPEP carboxykinase activity was not recovered in the intact chloroplasts.The same results were obtained with P. texanum, C. gayana andE. borumensis. Therefore, we conclude that PEP carboxykinase is exclusivelylocalized in the cytoplasm of bundle sheath cells of C₄ plants. (Received July 23, 1983; Accepted October 17, 1983)     

Larvae of Diagramma pictum (Haemulidae) from Tosa Bay, Japan

Preflexion to postflexion larvae (2.1–8.0 mm) of Diagramma pictum (Haemulidae) occur in coastal Tosa Bay, Japan from May to September. They can be distinguished from the other haemulid larvae by head spination, location of anus, and melanophore patterns. Compared with larvae identified as the same species from Australia, there are significantly morphological differentiations between the two areas. Thus, these significant differences are likely a reflection of subspecific differences.     

Comparison of Photosynthetic and Photorespiratory Enzyme Activities between Green Leaves and Colorless Parts of Variegated Leaves of a C4 Plant, Stenotaphrum secundatum (Walt.) Kuntze

The activities of enzymes involved in C⁴ photosynthesis andphotorespiration in colorless parts of variegated leaves ofStenotaphrum secundatum (Walt.) Kuntze were compared with thosein green leaves. Chlorophyll content of the colorless part wasonly about 0.3–3% of that of the green leaves. The activities of chloroplastic enzymes, pyruvate, P_i dikinase,NADP⁺-malic enzyme and NADP⁺-glyceraldehyde 3-phosphate dehydrogenasewere considerably lower in colorless tissue on a fresh weightor protein basis (the ratios of the activities in the green/colorlesstissues ranging from 5 to 20). A cytoplasmic enzyme, UDP-glucosepyrophosphorylase as well as aspartate and alanine aminotransferasesshowed comparable activities in the two types of tissue, whereasPEP carboxylase in the colorless tissue had only the one-thirdactivity of that in green tissue. Differences in activitieswere also observed for the glycolate pathway enzymes (the ratiosranging from 2 to 7 for glycolate oxidase, hydroxypyruvate reductaseand serine hydroxymethyltransferase, and 7 to 15 for catalase),while cytochrome c oxidase showed comparable activity in thetwo types of tissue. The results suggest that the deficiency of thylakoid developmentin the colorless tissue influences enzyme activities not onlyin plastids but also in other cellular compartments. ¹Present address: Institute of Applied Microbiology, Universityof Tokyo, Tokyo 113, Japan. (Received March 26, 1986; Accepted June 17, 1986)     

Age-related decrease of pulmonary metastasis of rat mammary carcinoma by activated natural resistance

We found that the number of pulmonary metastatic foci of spontaneously developed rat mammary carcinoma (SST-2), when transplanted subcutaneously in spontaneously hypertensive (SH) rats, decreased with aging. In the SST-2-bearing SH rats, it was observed that T cell functions progressively declined while activities of macrophages and natural killer cells were non-specifically activated by increasing age. To examine the mechanisms of the age-related decrease of pulmonary metastasis in SH rats, we treated the SST-2-bearing rats with anti-(asialo-GM1) antibody and/or carrageenan, which are known to suppress the functions of macrophages and natural killer cells, or with poly(I).poly(C), which is a stimulator to natural killer cells. The anti-(asialo-GM1) treatment significantly increased the number of pulmonary metastatic foci in both young and old SH rats, while poly(I).poly(C) significantly decreased the lung nodules in the old SH rats. These result suggest that the decrease of pulmonary metastasis in the SH rats with aging may be closely correlated with non-specifically activated natural killer cells and macrophages, though it should be also considered that non-immunological tumor-host interactions may be involved in the differences between the young and the old SH rats.     

Extracellular product of Nocardia amarae induces bacterial cell flocculation

The fact that Nocardia amarae YK1 produced a bacterial flocculation-inducing substance (designated as FIX) was discovered. FIX had a function of flocculating proliferous cells. FIX-induced flocculation was inhibited by making cells resting, but not completely by adding chloramphenicol. FIX worked widely on Gram-positive to -negative bacteria. In the presence of FIX, Achromobacter cycloclastus IAM1013, Acinetobacter calcoaceticus IAM1517, Bacillus subtilis IAM1069, Escherichia coli C600-1, E. coli IAM1239, Flavobacterium lutescens IAM1667, Klebsiella pneumoniae IAM1102, Micrococcus luteus IAM1313 and Pseudomonas putida IAM1002 formed flocs. B. cereus IAM1029, however, exhibited no flocculation.