|
|
|
|
|
|
InvB Is Required for Type III-Dependent Secretion of SopA in Salmonella enterica Serovar Typhimurium. Kristin Ehrbar, 2004.The Salmonella effector protein SopA is translocated into host cells via the SPI-1 type III secretion system [TTSS] and contributes to enteric disease . We found that the chaperone InvB binds toSopA and slightly stabilizes it in the bacterial cytosol andthat it is required for its transport via the SPI-1 TTSS. Isolates of Piscirickettsia salmonis from Scotland and Ireland Show Evidence of Clonal Diversity. H. I. Reid, 2004. The Klebsiella pneumoniae wabG Gene: Role in Biosynthesis of the Core Lipopolysaccharide and Virulence. Luis Izquierdo, 2003.To determine the function of the wabG gene in the biosynthesis of the core lipopolysaccharide (LPS) of Klebsiella pneumoniae, we constructed wabG nonpolar mutants . Data obtained from the comparative chemical and structural analysis of LPS samples obtained from the wild type, the mutant strain, and the complemented mutant demonstrated that the wabG gene is involved in attachment to  -L-glycero-D-manno-heptopyranose II
(L,D-HeppII) at the O-3 position of an
-D-galactopyranosyluronic acid
(-D-GalAp) residue . K . pneumoniae
nonpolar wabG mutants were devoid of the cell-attached
capsular polysaccharide but were still able to produce capsular
polysaccharide . Similar results were obtained with K.
pneumoniae nonpolar waaC and waaF mutants, which
produce shorter LPS core molecules than do wabG mutants . Other
outer core K . pneumoniae nonpolar mutants in the waa
gene cluster were encapsulated . K . pneumoniae waaC,
waaF, and wabG mutants were avirulent when tested in
different animal models . Furthermore, these mutants were more sensitive
to some hydrophobic compounds than the wild-type strains . All these
characteristics were rescued by reintroduction of the waaC,
waaF, and wabG genes from K.
pneumoniae .
A Labeling Study To Elucidate the Biosynthesis of 4-(4-Hydroxyphenyl)-Butan-2-one (Raspberry Ketone) by Nidula niveo-tomentosa. H. Zorn, 2003.Submerged cells of the basidiomycete Nidula niveo-tomentosa, a microbial producer of 4-(4-hydroxyphenyl)-butan-2-one, were supplemented with 13C-labeled L-phenylalanines and with [1-13C]glucose . Labeled transformation products were detected by a novel method of analyzing stable isotope-labeled metabolites, gas chromatography (GC) coupled to an atomic emission detector, and by GC-mass spectrometry . A benzoate moiety was side chain elongated according to the poly-ß-keto scheme . The presence of an acetyl coenzyme A-carboxylase inhibitor shifted the spectrum of products to benzyl compounds . Hence, the fungal pathway differs from the one established for plant tissues . Identification and Characterization of the CYP52 Family of Candida tropicalis ATCC 20336, Important for the Conversion of Fatty Acids and Alkanes to  , -Dicarboxylic Acids.David L. Craft, 2003.Candida tropicalis ATCC 20336 excretes ,-dicarboxylic acids as a by-product when cultured on n-alkanes or fatty acids as the carbon source . Previously, a ß-oxidation-blocked derivative of ATCC 20336 was constructed which showed a dramatic increase in the production of dicarboxylic acids . This paper describes the next steps in strain improvement, which were directed toward the isolation and characterization of genes encoding the
-hydroxylase enzymes catalyzing the first step in the
-oxidation pathway . Cytochrome P450 monooxygenase (CYP) and the accompanying NADPH cytochrome P450 reductase (NCP) constitute the hydroxylase complex responsible for the first and rate-limiting step of
-oxidation of n-alkanes and fatty acids . 10 members of the alkane-inducible P450 gene family (CYP52) of C . tropicalis ATCC20336 as well as the accompanying NCP were cloned and sequenced . The 10 CYP genes represent four unique genes with their putative alleles and two unique genes for which no allelic variant was identified . Of the 10 genes, CYP52A13 and CYP52A14 showed the highest levels of mRNA induction, as determined by quantitative competitive reverse transcription-PCR during fermentation with pure oleic fatty acid (27-fold increase), pure octadecane (32-fold increase), and a mixed fatty acid feed, Emersol 267 (54-fold increase) . The allelic pair CYP52A17 and CYP52A18 was also induced under all three conditions but to a lesser extent . Moderate induction of CYP52A12 was observed . These results identify the CYP52 and NCP genes as being involved in
,-dicarboxylic acid production by C . tropicalis and provide the foundation for biocatalyst improvement .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
