Isolation for bacteria and fungi for the hydrolysis of phthalate and terephthalate esters

Bacterial and fungal strains were isolated from enrichment cultures using diethylphthalate, diethylterephthalate, or ethylene glycol dibenzoate as sole carbon sources.Aureobacterium, Flavobacterium, andMicrococcus species were isolated from diethylphthalate enrichments;Rhodococcus andXanthomonas species were isolated from diethylterephthalate enrichments;Rhodococcus andFusarium species were isolated from ethylene glycol dibenzoate enrichments.     

Partial characterization of chitinolytic enzymes from Streptomyces albidoflavus

Streptomyces albidoflavus NRRL B-16746 secreted three types of chitinolytic enzymes: N -acetyl-glucosaminidase, chitobiosidase and endochitinase. Optimal activity for all three types of enzymes occurred at pH 4–6; however 55–74% of the chitobiosidase and endochitinase activity was detectable at pH 8–10. Chitobiosidase activity originated from two strongly acidic (pI < 3.0) proteins with molecular mass of 27 kDa and 34 kDa, while endochitinase activity originated from five major acidic proteins (pI 5.1, 5.3, 5.75, 5.8–5.9 and 6.4) with molecular mass of 59, 45, 38.5, 27 and 25.5 kDa. Purified chitobiosidases significantly reduced spore germination and germ tube elongation of Botrytis cinerea and Fusarium oxysporum. Chitinolytic enzymes with significant activity at pH 4–10 may be used, transgenically, to reduce the growth and/or development of a broad spectrum of insects and fungi that are major economic pests.     

Multi-locus variable-number tandem repeat profiling of Salmonella enterica serovar Typhi isolates from blood cultures and gallbladder specimens from Makassar, South-Sulawesi, Indonesia

Multi-locus variable-number tandem repeat analysis differentiated 297 Salmonella enterica serovar Typhi blood culture isolates from Makassar in 76 genotypes and a single unique S. Typhi genotype was isolated from the cholecystectomy specimens of four patients with cholelithiasis. The high diversity in S. Typhi genotypes circulating in Makassar indicates that the number of carriers could be very large, which may complicate disease prevention and control.     

Production of 10-Hydroxy-8(E)-Octadecenoic Acid from Oleic Acid Conversion by Strains of Pseudomonas aeruginosa

Eighteen Pseudomonas aeruginosa strains were examined for their ability to convert oleic acid to produce 10-hydroxy-8(E)-octadecenoic acid (HOD), which was structurally confirmed by GC-MS, NMR, and FTIR. There were no substantial amounts of other new compounds found in the fermentation broths in addition to HOD and 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). The results demonstrated that P. aeruginosa strains possessed varying levels of activity for producing HOD. Under the experimental conditions, strain NRRL B-14938 isolated from sheep manure was the best HOD producer exhibiting the highest HOD to DOD product ratio in the medium most suitable for purifying HOD. Using strain B-14938 as a model system for further characterization, optimum conditions for producing HOD were found to be at 26°C and pH 7.0 after 60 h of reaction time using a medium containing EDTA as a chelating agent. This study has identified a high-yielding P. aeruginosa strain and provided the reaction characteristics needed to develop a scale-up production process of HOD for testing its properties and potential new uses.     

Plating Isolation of Various Catalase-Negative Microorganisms from Soil

A procedure using nutritionally minimal media is presented for the plating isolation, but not enumeration, of various catalase-negative microorganisms from soil.     

Microbial production of a novel trihydroxy unsaturated fatty acid from linoleic acid

A bacterium isolated from a dry soil sample collected from McCalla, AL, USA, converted linoleic acid to a novel compound, 12,13,17-trihydroxy-9 (Z)-octadecenoic acid (THOA). The organism is a Gram-positive, non-motile rod (0.5 μ m × 2 μ m). It was identified as a species of Clavibacter ALA2. The product was purified by high pressure liquid chromatography, and its structure was determined by ¹H and ¹³C nuclear magnetic resonance and Fourier transform infrared spectroscopies, and by mass spectrometer. Maximum production of THOA with 25% conversion of the substrate was reached after 5–6 days of reaction. THOA was not further metabolized by strain ALA2. This is the first report of a 12,13,17-trihydroxy unsaturated fatty acid and its production by microbial transformation. Some dihydroxy intermediates were also detected. THOA has a structure similar to those of known plant self-defense substances. Received 13 January 1997/ Accepted in revised form 05 May 1997     

Critical role of anteiso-C15:0 fatty acid in the growth of Listeria monocytogenes at low temperatures.

Listeria monocytogenes is a food-borne pathogen capable of growth at refrigeration temperatures. Membrane lipid fatty acids are major determinants of a sufficiently fluid membrane state to allow growth at low temperatures. L. monocytogenes was characterized by a fatty acid profile dominated to an unusual extent (> 95%) by branched-chain fatty acids, with the major fatty acids being anteiso-C15:0, anteiso-C17:0, and iso-C15:0 in cultures grown in complex or defined media at 37 degrees C. Determination of the fatty acid composition of L. monocytogenes 10403S and SLCC 53 grown over the temperature range 45 to 5 degrees C revealed two modes of adaptation of fatty acid composition to lower growth temperatures: (i) shortening of fatty acid chain length and (ii) alteration of branching from iso to anteiso. Two transposon Tn917-induced cold-sensitive mutants incapable of growth at low temperatures had dramatically altered fatty acid compositions with low levels of i-C15:0, a-C15:0, and a-C17:0 and high levels of i-C14:0, C14:0, i-C16:0, and C16:0. The levels of a-C15:0 and a-C17:0 and the ability to grow at low temperatures were restored by supplementing media with 2-methylbutyric acid, presumably because it acted as a precursor of methylbutyryl coenzyme A, the primer for synthesis of anteiso odd-numbered fatty acids. When mid-exponential-phase 10403S cells grown at 37 degrees C were temperature down-shocked to 5 degrees C they were able, for the most part, to reinitiate growth before the membrane fatty acid composition had reset to a composition more typical for low-temperature growth. No obvious evidence was found for a role for fatty acid unsaturation in adaptation of L. monocytogenes to cold temperature. The switch to a fatty acid profile dominated by a-C15:0 at low temperatures and the association of cold sensitivity with deficiency of a-C15:0 focus attention on the critical role of this fatty acid in growth of L. monocytogenes in the cold, presumably through its physical properties and their effects, in maintaining a fluid, liquid-crystalline state of the membrane lipids.     

DNA relatedness among strains of the sweet potato pathogen Streptomyces ipomoea (Person and Martin 1940) Waksman and Henrici 1948.

DNA relatedness among 28 putative strains of Streptomyces ipomoea from geographically diverse locations and the type strain, NRRL B-12321, was determined spectrophotometrically. The data confirm that these 28 strains are not closely related genetically to the plant-pathogenic species Streptomyces scabies (39% DNA relatedness) or Streptomyces acidiscabies (17% DNA relatedness) or any other major blue-spored Streptomyces species (less than 30% DNA relatedness). Of the 29 strains examined, 4 could be clearly distinguished from S. ipomoea on the basis of morphological criteria, i.e., they had gray rather than blue spores and produced melanin pigment, and their low DNA relatedness to authentic S. ipomoea strains confirmed their original misidentification. The remaining 25 S. ipomoea strains exhibited high DNA relatedness among themselves (76 to 100% homology), even though they had been isolated in different locations throughout the United States and Japan. The avirulent type strain, NRRL B-12321, exhibited slightly lower DNA relatedness with the virulent strains of S. ipomoea (85% average DNA relatedness) than was observed among the virulent strains (average of 96% DNA relatedness).     

Streptomyces leeuwenhoekii sp. nov., the producer of chaxalactins and chaxamycins,forms a distinct branch in Streptomyces gene trees

A polyphasic study was carried out to establish the taxonomic status of an Atacama Desert isolate, Streptomyces strain C34^T, which synthesises novel antibiotics, the chaxalactins and chaxamycins. The organism was shown to have chemotaxonomic, cultural and morphological properties consistent with its classification in the genus Streptomyces. Analysis of 16S rRNA gene sequences showed that strain C34^T formed a distinct phyletic line in the Streptomyces gene tree that was very loosely associated with the type strains of several Streptomyces species. Multilocus sequence analysis based on five house-keeping gene alleles underpinned the separation of strain C34^T from all of its nearest phylogenetic neighbours, apart from Streptomyces chiangmaiensis TA-1^T and Streptomyces hyderabadensis OU-40^T which are not currently in the MLSA database. Strain C34^T was distinguished readily from the S. chiangmaiensis and S. hyderabadensis strains by using a combination of cultural and phenotypic data. Consequently, strain C34^T is considered to represent a new species of the genus Streptomyces for which the name Streptomyces leeuwenhoekii sp. nov. is proposed. The type strain is C34^T (= DSM 42122^T = NRRL B-24963^T). Analysis of the whole-genome sequence of S. leeuwenhoekii, with 6,780 predicted open reading frames and a total genome size of around 7.86 Mb, revealed a high potential for natural product biosynthesis.     

Simplified procedures for releasing and concentrating microorganisms from soil for transmission electron microscopy viewing as thin-sectioned and frozen-etched preparations.

A simplified procedure is presented for releasing and concentrating indigenous microbial cells from soil for viewing by transmission electron microscopy as thin sections or replicas of frozen-etched preparations. This procedure is compared with two others reported earlier, and their relative merits are discussed as concerns the choice of procedure for the cellular information desired from the soil. Freeze-etching showed that the cell types and size distributions for cells which have been released and concentrated from soil are in general agreement with those for cells in a crude soil slurry in which no attempt to release and concentrate cells was made. Microcolonies were present both in the crude slurry and in the discard soil debris centrifugation pellets from the cell release and concentration procedures. In contrast to the historic assumptions, these microcolonies, as well as some individual cells embedded in soil debris could not be broken up and (or) dislodged so that they would be washed from the soil. The relative numbers of these cells remaining with the soil debris, however, could not be quantitated in the present study.