Abstract:
:Many microorganisms produce surface-active substances that enhance the availability of water-insoluble substrates. Although many of these biosurfactants have interesting potential applications, very little is known about their biosynthesis. The basidiomycetous fungus Ustilago maydis secretes large amounts of mannosylerythritol lipids (MELs) under conditions of nitrogen starvation. We recently described a putative glycosyltransferase, Emt1, which is essential for MEL biosynthesis and whose expression is strongly induced by nitrogen limitation. We used DNA microarray analysis to identify additional genes involved in MEL biosynthesis. Here we show that emt1 is part of a gene cluster which comprises five open reading frames. Three of the newly identified proteins, Mac1, Mac2, and Mat1, contain short sequence motifs characteristic for acyl- and acetyltransferases. Mutational analysis revealed that Mac1 and Mac2 are essential for MEL production, which suggests that they are involved in the acylation of mannosylerythritol. Deletion of mat1 resulted in the secretion of completely deacetylated MELs, as determined by mass spectrometry. We overexpressed Mat1 in Escherichia coli and demonstrated that this enzyme acts as an acetyl coenzyme A-dependent acetyltransferase. Remarkably, Mat1 displays relaxed regioselectivity and is able to acetylate mannosylerythritol at both the C-4 and C-6 hydroxyl groups. Based on these results, we propose a biosynthesis pathway for the generation of mannosylerythritol lipids in U. maydis.
journal_name
Appl Environ Microbioljournal_title
Applied and environmental microbiologyauthors
Hewald S,Linne U,Scherer M,Marahiel MA,Kämper J,Bölker Mdoi
10.1128/AEM.00506-06subject
Has Abstractpub_date
2006-08-01 00:00:00pages
5469-77issue
8eissn
0099-2240issn
1098-5336pii
72/8/5469journal_volume
72pub_type
杂志文章abstract::Rates of dissolved inorganic carbon (DIC), formate, and acetate mineralization and/or assimilation were determined in 13 high-temperature (>73 °C) hot springs in Yellowstone National Park (YNP), Wyoming, in order to evaluate the relative importance of these substrates in supporting microbial metabolism. While 9 of the...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00511-15
更新日期:2015-06-01 00:00:00
abstract::A multiplex fluorogenic PCR assay for simultaneous detection of pathogenic Salmonella strains and Escherichia coli O157:H7 was developed and evaluated for use in detecting very low levels of these pathogens in meat and feces. Two sets of primers were used to amplify a junctional segment of virulence genes sipB and sip...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.66.12.5472-5476.2000
更新日期:2000-12-01 00:00:00
abstract::Confocal scanning laser microscopy (CSLM) was used to demonstrate the attachment of Escherichia coli O157:H7 transformed with a plasmid encoding for green fluorescent protein (GFP) to the surface and within the internal structures of nonwaxed Red Delicious cv. apples. Apples at 2 or 25 degrees C were inoculated with a...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.66.11.4679-4687.2000
更新日期:2000-11-01 00:00:00
abstract::The aim of this work was to investigate the medium requirements for growth and production of exopolysaccharides by Lactobacillus delbrueckii subsp. bulgaricus NCFB 2772. The strain was grown in batch cultures on a chemically defined medium, and the technique of single omission of medium components was applied to deter...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.64.4.1333-1337.1998
更新日期:1998-04-01 00:00:00
abstract::Short sequence repeats (SSRs) with a potential variable number of tandem repeat (VNTR) loci were identified in the genome of the citrus pathogen Xylella fastidiosa and used for typing studies. Although mono- and dinucleotide repeats were absent, we found several intermediate-length 7-, 8-, and 9-nucleotide repeats, wh...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.67.9.4091-4095.2001
更新日期:2001-09-01 00:00:00
abstract::Strains of Ascochyta rabiei which are pathogenic to chickpea (Cicer arietinum L.) readily catabolized the main chickpea isoflavone biochanin A (5,7-dihydroxy-4'-methoxyisoflavone). 3'-Hydroxylation and O-demethylation reactions led to the isoflavones pratensein, genistein, and orobol, which were rapidly further degrad...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.50.1.45-48.1985
更新日期:1985-07-01 00:00:00
abstract::Vector competence refers to the ability of an arthropod to acquire, maintain, and successfully transmit a microbial pathogen. Tick-borne relapsing fever (TBRF) spirochetes are globally distributed pathogens, and most species are transmitted by argasid ticks of the genus Ornithodoros. A defining characteristic in vecto...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01505-18
更新日期:2018-10-17 00:00:00
abstract::Submerged cultures of Penicillium urticae (NRRL 2159A) produced the antibiotics patulin and griseofulvin when grown in a glucose-nitrate medium. A high concentration of calcium (i.e., 68 mM) inhibited the production of both antibiotics while stimulating conidiogenesis. Conidial mutants that were defective in an early ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.33.1.147-158.1977
更新日期:1977-01-01 00:00:00
abstract::Marine infaunal burrows and tubes greatly enhance solute transport between sediments and the overlying water column and are sites of elevated microbial activity. Biotic and abiotic controls of the compositions and activities of burrow and tube microbial communities are poorly understood. The microbial communities in t...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.70.12.7053-7065.2004
更新日期:2004-12-01 00:00:00
abstract::pAM beta 1, a 26.5-kilobase plasmid originally isolated from Streptococcus faecalis, was conjugally transferred from Streptococcus lactis to Bacillus subtilis. No conjugal transfer of pAM beta 1 from B. subtilis to S. lactis was observed. In addition, pAM beta 1 which had been reintroduced in S. lactis after cycling t...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.53.10.2458-2463.1987
更新日期:1987-10-01 00:00:00
abstract::The isolation of auxotrophic mutants, which is a prerequisite for a substantial genetic analysis and metabolic engineering of obligate methylotrophs, remains a rather complicated task. We describe a novel method of constructing mutants of the bacterium Methylophilus methylotrophus AS1 that are auxotrophic for aromatic...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.02217-09
更新日期:2010-01-01 00:00:00
abstract::Sakacin K is an antilisterial bacteriocin produced by Lactobacillus sake CTC 494, a strain isolated from Spanish dry fermented sausages. The biokinetics of cell growth and bacteriocin production of L. sake CTC 494 in vitro during laboratory fermentations were investigated by making use of MRS broth. The data obtained ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.65.3.974-981.1999
更新日期:1999-03-01 00:00:00
abstract::The influence of nisin on the proton motive force (delta p) generated by glucose-energized cells of the obligate putrefactive anaerobe Clostridium sporogenes PA 3679 was determined. The components of delta p, the transmembrane potential (delta psi) and the pH gradient (delta pH), were determined from the distributions...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.58.8.2463-2467.1992
更新日期:1992-08-01 00:00:00
abstract::The diffusive penetration of fluorescently tagged macromolecular solutes into model oral biofilms was visualized by time-lapse microscopy. All of the solutes tested, including dextrans, proteases, green fluorescent protein, and immunoglobulin G, accessed the interior of cell clusters 100 to 200 microm in diameter with...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.02279-08
更新日期:2009-03-01 00:00:00
abstract::The psychrotolerant acidophile Acidithiobacillus ferrivorans has been identified from cold environments and has been shown to use ferrous iron and inorganic sulfur compounds as its energy sources. A bioinformatic evaluation presented in this study suggested that Acidithiobacillus ferrivorans utilized a ferrous iron ox...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.02989-12
更新日期:2013-02-01 00:00:00
abstract::Species diversity, phylogenetic affiliations, and environmental occurrence patterns of thiosulfate-oxidizing marine bacteria were investigated by using new isolates from serially diluted continental slope and deep-sea abyssal plain sediments collected off the coast of New England and strains cultured previously from G...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.66.8.3125-3133.2000
更新日期:2000-08-01 00:00:00
abstract::We describe a new enzymatic functionality for the surface layer (S-layer) of Lactobacillus acidophilus ATCC 4356, namely, an endopeptidase activity against the cell wall of Salmonella enterica serovar Newport, assayed via zymograms and identified by Western blotting. Based on amino acid sequence comparisons, the hydro...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01712-08
更新日期:2008-12-01 00:00:00
abstract::A new thermostable dipeptidase gene was cloned from the thermophile Brevibacillus borstelensis BCS-1 by genetic complementation of the D-Glu auxotroph Escherichia coli WM335 on a plate containing D-Ala-D-Glu. Nucleotide sequence analysis revealed that the gene included an open reading frame coding for a 307-amino-acid...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.70.3.1570-1575.2004
更新日期:2004-03-01 00:00:00
abstract::The induction of hydroxyl radical (OH) production via quinone redox cycling in white-rot fungi was investigated to improve pollutant degradation. In particular, we examined the influence of 4-methoxybenzaldehyde (anisaldehyde), Mn(2+), and oxalate on Pleurotus eryngii OH generation. Our standard quinone redox cycling ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.02138-08
更新日期:2009-06-01 00:00:00
abstract::This research documents an effect of reactor turbulence on the ability of gram-negative wastewater biofilm bacteria to actively transport l-aspartate via a binding-protein-mediated transport system. Biofilms which were not preadapted to turbulence and which possessed two separate and distinct aspartate transport syste...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.50.1.120-124.1985
更新日期:1985-07-01 00:00:00
abstract::Bacillus megaterium P1, a bacterial strain capable of hydrolyzing chitosan, was isolated from soil samples. Chitosan-degrading activity was induced by chitosan but not by its constituent d-glucosamine. Extracellular secretion of chitosanase reached levels corresponding to 1 U/ml under optimal conditions. Three chitosa...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.56.4.844-848.1990
更新日期:1990-04-01 00:00:00
abstract::A total of 1,794 migrating birds trapped at a coastal site in southern Sweden were sampled for detection of Campylobacter spp. All isolates phenotypically identified as Campylobacter jejuni and a subset of those identified as non-C. jejuni were identified to the species level by PCR-based techniques. C. jejuni was fou...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.68.12.5911-5917.2002
更新日期:2002-12-01 00:00:00
abstract::The endoglucanases of the thermophilic actinomycete Thermomonospora curvata were characterized. Early-exponential-phase culture fluid contained at least three endoglucanases, with molecular weights of 23,000, 46,000, and 146,000 and K(m) values of 1.54, 3.60, and 1.32% carboxymethyl cellulose, respectively. The statio...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.54.2.588-589.1988
更新日期:1988-02-01 00:00:00
abstract::An acetate-fermenting strain of Methanosarcina was isolated from an acetate enrichment culture inoculated with anaerobic sludge from a waste treatment digestor. In pure culture, this organism fermented acetate in the absence of added hydrogen at rates comparable in magnitude to those found in digestor systems. This ra...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.35.6.1174-1184.1978
更新日期:1978-06-01 00:00:00
abstract::The bacterial communities associated with the development of necroses in injured agria cactus tissue were examined in the field by using both human-induced injuries and cactus tissue inoculated with cactophilic bacteria. Whole-cell bacterial fatty acids were used to determine when and where each of 23 detected species...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.60.2.619-625.1994
更新日期:1994-02-01 00:00:00
abstract::A real-time PCR-based method targeting the 18S rRNA gene was developed for the quantitative detection of Hartmannella vermiformis, a free-living amoeba which is a potential host for Legionella pneumophila in warm water systems and cooling towers. The detection specificity was validated using genomic DNA of the closely...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00085-06
更新日期:2006-09-01 00:00:00
abstract::Transfer of plasmid-borne antibiotic resistance genes in Escherichia coli wild-type strains is possible by transformation under naturally occurring conditions in oligotrophic, aquatic environments containing physiologic concentrations of calcium. In contrast, transformation is suppressed in nitrogen-rich body fluids l...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.68.1.440-443.2002
更新日期:2002-01-01 00:00:00
abstract::To ascertain whether position 131 of a mesophilic protease, subtilisin BPN', is a potential critical site for cold adaptation as screened by evolutionary engineering (S. Taguchi, A. Ozaki, and H. Momose, Appl. Environ. Microbiol. 64:492-495, 1998), a full set of subtilisin BPN' mutants with mutations at position 131 w...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.66.4.1410-1415.2000
更新日期:2000-04-01 00:00:00
abstract::The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates o...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.67.3.1116-1122.2001
更新日期:2001-03-01 00:00:00
abstract::The lysogenic bacteriophage APSE infects "Candidatus Hamiltonella defensa," a facultative endosymbiont of aphids and other sap-feeding insects. This endosymbiont has established a beneficial association with aphids, increasing survivorship following attack by parasitoid wasps. Although APSE and "Ca. Hamiltonella defen...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01285-08
更新日期:2008-11-01 00:00:00