Efficient degradation of trichloroethylene by a hybrid aromatic ring dioxygenase.

Engineering of hybrid gene clusters between the toluene metabolic tod operon and the biphenyl metabolic bph operon greatly enhanced the rate of biodegradation of trichloroethylene. Escherichia coli cells carrying a hybrid gene cluster composed of todC1 (the gene encoding the large subunit of toluene terminal dioxygenase in Pseudomonas putida F1), bphA2 (the gene encoding the small subunit of biphenyl terminal dioxygenase in Pseudomonas pseudoalcaligenes KF707), bphA3 (the gene encoding ferredoxin in KF707), and bphA4 (the gene encoding ferredoxin reductase in KF707) degraded trichloroethylene much faster than E. coli cells carrying the original toluene dioxygenase genes (todC1C2BA) or the original biphenyl dioxygenase genes (bphA1A2A3A4).     

Interfacial and micellar behavior of glucose lipid

Summary Glucose lipid of notable surfactant properties was produced by using hydrocarbon assimilating bacterium of the bacterial strain MM1. Its surface active properties were notable in spite of ,-hydrophilic and bulky molecule. The critical micelle concentration (cmc) was small (0.165 M); surface and interfacial tension for hexadecane at 0.1 % (pH 7.35) solution, 24.6 and 13.3 mN/m, respectively. The emulsifying action was excellent and comparable to those of rhamnolipids. The micelle has the outer radius. 28.5 Å and inner core, 6.7 Å on the basis of the concentric spherical shell model by means of the small angle X-ray solution scattering measurement.Dedicated to Professor Fritz Wagner on the occasion of his 65th birthday.     

Euphausia superba dominates in the diet of Adélie penguins feeding under fast sea-ice in the shelf areas of Enderby Land in summer

Adélie penguins Pygoscelis adeliae in Enderby Land, Antarctica feed mainly on Euphausia superba during the chick rearing season in shelf areas where fast sea-ice remains: indicating that E. superba is abundant under the fast sea-ice in these areas. The shelf areas in Enderby Land, therefore, are unique since the previous studies of Adélie penguin diet in Ross Sea, Adélie Land and Prydz Bay show that E. crystallorophias is the most abundant krill species in shelf areas in general.     

(2S)-2-Amino-5-chloro-4-hydroxy-5-hexenoic acid,a new chloroamino acid,and related compounds fromAmanita gymnopus

Combining different chromatography systems, unusual nonprotein amino acids were isolated and unequivocally identified from a small amount (less than 100 g fresh weight) ofAmanita gymnopus fruit body. Without obtaining crystals of these amino acids, on the basis of¹H-NMR determination, high resolution mass spectrometry, chlorine analysis and oxidation with L-amino acid oxidase, one of them proved to be a new chloroamino acid, (2S)-2-amino-5-chloro-4-hydroxy-5-hexenoic acid (G2). The other three were (2S)-2-amino-5-hexenoic acid (G1), (2S)-2-amino-4,5-hexadienoic acid (G3) and (2S)-2-amino-5-hexynoic acid (G4). Amino acid (G1) was also encountered for the first time in natural products. Amino acid (G3) has been reported from several kinds of fungi belonging toAmanita, subgenusLepidella. The occurrence of amino acid (G4) was already reported fromCortinarius claricolor.Part 23 in the series Biochemical studies of nitrogen compounds in fungi. Part 22, Hatanaka, S. I. et al. 1985. Trans. Mycol. Soc. Japan26: 61–68.     

A Novel Method for Generating Nested Deletions Using the in Vitro Bacteriophage T3 DNA Packaging System

To sequence a DNA segment inserted into a cosmid vector underthe directed sequencing strategy, we established a simple andrapid method for generating nested deletions which uses thein vitro packaging system of bacteriophage T3 DNA. The principleis based on the previous finding that this system can translocateany linear double-stranded DNA up to 40 kb into the phage capsidin a time-dependent manner and the encapsulated DNA becomesDNase-resistant. For this purpose, we constructed a cosmid vectorthat carries two different antibiotic selection markers at bothsides of the multiple cloning site, and after insertion of aDNA segment, the clone was linearized by -terminase at the cossite. After the packaging reaction in vitro followed by DNasetreatment, the encapsulated DNA was introduced into Escherichiacoli cells to give clones with unidirectional deletions by differentialantibiotic selection. Restriction and sequence analyses of deletionclones demonstrated that an ordered set of clones with nesteddeletions, ranging from less than 1 kb to 25 kb, was createdfrom either the end of the DNA segment. Thus, nested deletionclones that cover the entire region of a 40-kb cosmid insertcan be obtained by a single packaging reaction, and its restrictionmap can be simultaneously obtained.     

A Factor That Interrupts the Cell Cycle at G2 or Prophase is Present in Full-Grown Frog Oocytes

Full-grown amphibian oocytes that had been arrested at meiotic prophase I contained an activity that prevented the cell cycle from progressing beyond a G₂-like stage. Injection of the contents of germinal vesicles (GV-content) or cytoplasm obtained from oocytes of the frog Rana rugosa prevented fertilized eggs of Cynops pyrrhogaster or Bufo japonicus from cleaving. The nuclei in the arrested eggs consisted of thin chromosomes and nucleolus-like particles enclosed within clear nuclear membrane and their volume increased as a function of time after injection. Cycling of maturation-promoting factor (MPF) did not occur in the injected eggs, but DNA synthesis was not disturbed. The injection of exogenous MPF into the eggs induced the reinitiation of the cell cycle with progression to the M phase and subsequent cleavage. Furthermore, the injection into the full-grown oocytes of Bufo inhibited induction of the maturation of oocytes by progesterone. These results demonstrate that a factor that arrests the cell cycle either at a G₂-like stage of mitosis or at prophase in meiosis is present both in the GV and cytoplasm of frog oocytes. We refer to this factor as a G₂-specific cytostatic factor (G₂-CSF). G₂-CSF may play an important role not only in the physiological arrest at prophase I in meiosis, but also in regulation of the G₂/M transition in the cell cycle of early embryonic cells.     

cDNA cloning and mRNA expression of calponin and SM22 in rat aorta smooth muscle cells

We cloned and sequenced cDNAs encoding calponin (Calp) and SM22 (smooth muscle-specific 22-kDa protein) from rat aorta (RaA) smooth muscle (Smu) cells. The 1504-bp calp cDNA contains a single open reading frame (ORF) which encodes 297 amino acids (aa) (M_r 33 342). The 1186-bp SM22 cDNA contains a single ORF which encodes 201 aa (M_r 22 601). There were 43% identical aa in a 181-aa overlap between RaA Calp and SM22. Especially for the C-terminal region of SM22 and for the first repeat motif of Calp, 70% identity was observed. Northern blot analysis revealed that the calp and SM22 mRNAs were expressed in RaA Smu, but not in rat cardiac and skeletal muscles. SM22 mRNA was much more abundant than calp mRNA in RaA (3- to 4-fold). The expression levels of the calp and SM22 mRNAs in RaA showed a significant increase for 5 to 15 week old rats (1.5- to 3-fold) with vascular development and blood pressure elevation. No significant differences were observed in the expression of the RaA calp and SM22 mRNAs between normotensive (Wistar Kyoto) and spontaneously hypertensive rats (SHR).