Biodegradation of the gasoline oxygenates methyl tert-butyl ether, ethyl tert-butyl ether, and tert-amyl methyl ether by propane-oxidizing bacteria

Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and natural isolates were able to degrade each compound after growth on propane. When propane-grown strain ENV425 was incubated with 20 mg of uniformly labeled [14C]MTBE per liter, the strain converted > 60% of the added MTBE to 14CO2 in < 30 h. The initial oxidation of MTBE and ETBE resulted in the production of nearly stoichiometric amounts of tert-butyl alcohol (TBA), while the initial oxidation of TAME resulted in the production of tert-amyl alcohol. The methoxy methyl group of MTBE was oxidized to formaldehyde and ultimately to CO2. TBA was further oxidized to 2-methyl-2-hydroxy-1-propanol and then 2-hydroxy isobutyric acid; however, neither of these degradation products was an effective growth substrate for the propane oxidizers. Analysis of cell extracts of ENV425 and experiments with enzyme inhibitors implicated a soluble P-450 enzyme in the oxidation of both MTBE and TBA. MTBE was oxidized to TBA by camphor-grown Pseudomonas putida CAM, which produces the well-characterized P-450cam, but not by Rhodococcus rhodochrous 116, which produces two P-450 enzymes. Rates of MTBE degradation by propane-oxidizing strains ranged from 3.9 to 9.2 nmol/min/mg of cell protein at 28 degrees C, whereas TBA was oxidized at a rate of only 1.8 to 2.4 nmol/min/mg of cell protein at the same temperature.     

Exposure to methyl tertiary-butyl ether from oxygenated gasoline in Stamford, Connecticut

In 1993, state health officials in Connecticut invited the Centers for Disease Control and Prevention (CDC) to assist in an investigation of exposure to methyl tertiary-butyl ether in oxygenated gasoline in Stamford, Connecticut. Venous blood samples were collected from 14 commuters and from 30 other persons who worked in the vicinity of traffic or automobiles, and the samples were analyzed for methyl tertiary-butyl ether, tertiary-butyl alcohol, benzene, m-/p-xylene, o-xylene, and toluene. The highest levels of methyl tertiary-butyl ether in blood were measured among gasoline service station attendants (median = 15 micrograms/l, range = 7.6-28.9 micrograms/l). Blood levels of methyl tertiary-butyl ether were highly variable among persons who worked in car-repair shops (median = 1.73 micrograms/l, range = 0.17-36.7 micrograms/l) and were generally lowest among commuters (median = 0.11 micrograms/l, range = < 0.05-2.60 micrograms/l). Blood levels of methyl tertiary-butyl ether were correlated strongly with personal-breathing-zone samples of methyl tertiary-butyl ether and blood levels of other volatile organic compounds. This exposure information should prove useful to a future risk analysis of this high-volume chemical.     

Demethyl mutactimycins, new anthracycline antibiotics from Nocardia and Streptomyces strains

New anthracycline antibiotics 3'-O-demethyl mutactimycin (3) and 4-O,3'-O-didemethyl mutactimycin (4) were isolated from two actinomycetes strains, Nocardia transvalensis and Streptomyces sp. GW 60/1571. The chemical structures were elucidated by mass spectrometry and NMR spectroscopy. Antibiotic 3 displayed moderate antimicrobial activity against Gram-positive bacteria and cytotoxicity against P388, L1210 and HeLa tumor cells (IC50; 9.6, >25 and 20 microg/ml, respectively).     

A new AluI satellite DNA in the root-knot nematode Meloidogyne fallax: relationships with satellites from the sympatric species M. hapla and M. chitwoodi

A highly abundant satellite DNA comprising 20% of the Meloidogyne fallax (Nematoda, Tylenchida) genome was cloned and sequenced. The satellite monomer is 173 bp long and has a high A + T content of 72.3%, with frequent runs of A's and T's. The sequence variability of the monomers is 2.7%, mainly due to random distribution of single-point mutations. A search for evidence of internal repeated subunits in the monomer sequence revealed a 6-bp motif (AAATTT) for which five degenerated repeats, differing by just a single base pair, could be identified. Pairwise comparison of the M. fallax satellite with those from the sympatric species Meloidogyne chitwoodi and Meloidogyne hapla revealed a high sequence similarity (68.39%) with one satellite DNA subfamily in M. chitwoodi, which indicated an unexpected close relationship between them. Given the high copy number and the extreme sequence homogeneity among monomeric units, it may be assumed that the satellite DNA of M. fallax could have evolved through some recent and extensive amplification burst in the nematode genome. In this case, its relatively short life would not yet have allowed the accumulation of random mutations in independent amplified repeats. Considering the morphological resemblance between the two species and their ability to produce interspecific fertile hybrids under controlled conditions, these results indicate that M. fallax may share a common ancestor with M. chitwoodi, from which it could have diverged recently. All these data suggest that M. fallax could be the result of a recent speciation process and show that Meloidogyne satellite DNAs may be of interest to resolve phylogenetic relationships among closely related species from this genus.     

Isolation of a new antibiotic, laterosporamine. Studies on antibiotics from the genus Bacillus. XIII

A new antibiotic, named laterosporamine, was isolated from the culture broth of Bacillus laterosporus 340-19. The antibiotic is active against Gram-positive and Gram-negative bacteria in vitro and in vivo. It is a water-soluble basic substance, positive to ninhydrin, SAKAGUCHI'S and DRAGENDORFF'S reagents. A non-peptidic structure with an approximate empirical formula C17H35N7O4 was suggested.     

Production of antibiotics by Collybia nivalis, Omphalotus olearis, a Favolaschia and a Pterula species on natural substrates

Collybia nivalis, Favolaschia sp. 87129, Pterula sp. 82168 and Omphalotus olearius were cultivated on natural substrates. The antibiotic metabolites oudemansin A. strobilurins A, D, illudin S and pterulone were isolated and identified. A new antifungal metabolite, pterulone B, was described from cultures of Pterula sp. 82168 on wood. Collybia nivalis was found to be the first species of this genus to produce strobilurins and oudemansin A. As compared to rich media the cultivation on natural substrates resulted in the production of fewer metabolites. The concentrations of the antibiotics, however, were sufficient to inhibit other saprophytic fungi.     

叶盲蝽亚科中国一新记录种记述(半翅目盲蝽科)

记述采自中国甘肃省肃南半翅目(Hemiptera)盲蝽科(Miridae)叶盲蝽亚科(Phylinae)顶窝盲蝽属(Monosynamma)中国1新记录种--鲍氏顶窝盲蝽(Monosynamma bohemani Fallen,1829).标本存放于内蒙古师范大学生命科学与技术学院昆虫标本馆.     

Epoxyquinomicins A, B, C and D, new antibiotics from Amycolatopsis. I. Taxonomy, fermentation, isolation and antimicrobial activities

A new structural class of the antibiotic, epoxyquinomicins A, B, C and D were isolated from the culture broth of the strain MK299-95F4, which was related to Amycolatopsis sulphurea. Antimicrobial activity of epoxyquinomicins A and B were weak against Gram-positive bacteria, and epoxyquinomicins C and D showed almost no antimicrobial activity and no cytotoxicity. All these antibiotics showed improvement of collagen induced arthritis in vivo.     

Isolation of a new peptide antibiotic complex, B-43 (studies on antibiotics from the genus Bacillus. XV)

A new peptide antibiotic complex B-43, active against Gram-positive and Gram-negative bacteria, was isolated from a strain of Bacillus circulans. This antibiotic contains aspartic acid, valine, isoleucine, leucine, phenylalanine and 2,4-diaminobutyric acid. It seems to be related to polypeptin and antibiotic complex 4205, but differs in that it contains aspartic acid residue.     

The genus Hexidionis (Acari:Trombiculidae) with the description of a new species from Texas

Hexidionis garfieldi is described as new from specimens collected off a domestic cat. Felis silvestris f. catus Schreber, in Corpus Christi, TX. The genus Hexidionis Vercammen-Grandjean & Loomis, 1967, is rediagnosed and a key to the 11 included species given.     

Pharmacokinetic changes of M1, M2, M3 and M4 after intravenous administration of a new anthracycline, DA-125, to rats pretreated with phenobarbital, 3-methylcholanthrene, chloramphenicol, or SKF-525A

Aspergillus fumigatus is an important pathogen of the immunocompromised host causing pneumonia and invasive disseminated disease with high mortality. Previously, we identified a mutant strain (white, W) lacking conidial pigmentation and, in addition, the conidia showed a smooth surface morphology, whereas wild-type (WT) conidia are grey-green and have a typical ornamentation. W conidia appeared to be less protected against killing by the host defence, e.g., were more susceptible to oxidants in vitro and more efficiently damaged by human monocytes in vitro than WT conidia. When compared to the WT, the W mutant strain showed reduced virulence in a murine animal model. Genetic analysis suggested that the W mutant carried a single mutation which caused all of the observed phenotypes. Here. we report the construction of a genomic cosmid library of A. fumigatus and its use for complementation of the W mutant. Transformation of the W mutant was facilitated by co-transformation with plasmid pHELP1 carrying the autonomously replicating ama1 sequence of A. nidulans which also increased the transformation efficiency of A. fumigatus by a factor of 10. Using this cosmid library a putative polyketide synthase gene, designated pksP (polyketide synthase involved in pigment biosynthesis) was isolated. The pksP gene has a size of 6660 bp. pksP consists of five exons separated by short (47-73 bp) introns. Its deduced open reading frame is composed of 2146 amino acids. The pksP gene complemented both the white phenotype and the surface morphology of the W mutant conidia to wild type. Whereas W mutant conidia caused a strong reactive oxygen species (ROS) release by polymorphonuclear leukocytes, the ability of pksP-complemented W mutant conidia to stimulate ROS release was significantly reduced and comparable to that of WT conidia. In addition, the complemented strains showed restored virulence in a mouse model.     

Epoxyquinomicins A, B, C and D, new antibiotics from Amycolatopsis. II. Effect on type II collagen-induced arthritis in mice

The anti-arthritic effects of epoxyquinomicins on type II collagen-induced arthritis in DBA/1J mice were examined. Prophylactic treatment with epoxyquinomicins A, B, C and D (1-4 mg/kg) had potent inhibitory effects on type II collagen-induced arthritis. In contrast to nonsteroidal anti-inflammatory drugs (NSAIDs), epoxyquinomicin C (1-30 mg/kg) had neither an anti-inflammatory effect on carrageenan-induced paw edema in rats nor an analgesic effect on acetic acid-induced writhing in mice. These results suggest that the mode of action of epoxyquinomicins is different from that of NSAIDs and that epoxyquinomicins may become useful drugs for the treatment of rheumatoid arthritis.     

Fatal familial insomnia: genetic, neuropathologic, and biochemical study of a patient from a new Italian kindred

Fatal familial insomnia (FFI) is an inherited prion disease linked to a mutation at codon 178 of the PRNP gene that results in aspartic acid to asparagine substitution, in coupling phase with methionine at position 129. The disease is characterized clinically by insomnia with disturbances of the autonomic, endocrine, and motor systems and neuropathologically by selective degeneration of the thalamus. Phenotypic variability is well known and has been linked to homozygosity or heterozygosity at PRNP codon 129. We report the clinical, neuropathologic, and biochemical findings and genomic analysis of a patient with FFI from a new Italian kindred. Although homozygous for methionine at codon 129, this patient showed some clinical and pathologic features most commonly found in heterozygotes.