Publications

genetic diversity of african and worldwide strains of ralstonia solanacearum as determined by pcr-restriction fragment length polymorphism analysis of the hrp gene region	the genetic diversity among a worldwide collection of 120 strains of ralstonia solanacearum was assessed by restriction fragment length polymorphism (rflp) analysis of amplified fragments from the hrp gene region. five amplified fragments appeared to be specific to r. solanacearum. fifteen different profiles were identified among the 120 bacterial strains, and a hierarchical cluster analysis distributed them into eight clusters. each cluster included strains belonging to a single biovar, except ...	1999	10224018
self-regulation of pir, a regulatory protein responsible for hyperinduction of pectate lyase in erwinia chrysanthemi ec16.	previously, we have cloned and characterized the pir (plant inducible regulator) gene, which is responsible for hyperinduction of the synthesis of an isozyme of pectate lyase (ple) in erwinia chrysanthemi ec16 in the presence of potato extract and sodium polypectate (napp). the pir protein purified from escherichia coli overexpressing pir is able to bind to the promoter region of pir as a dimer. self-regulation of pir by its own translational product (pir) was suggested from the findings that pi ...	1999	10226371
growth of azospirillum irakense kbc1 on the aryl beta-glucoside salicin requires either sala or salb.	the rhizosphere nitrogen-fixing bacterium azospirillum irakense kbc1 is able to grow on pectin and beta-glucosides such as cellobiose, arbutin, and salicin. two adjacent genes, sala and salb, conferring beta-glucosidase activity to escherichia coli, have been identified in a cosmid library of a. irakense dna. the sala and salb enzymes preferentially hydrolyzed aryl beta-glucosides. a delta(sala-salb) a. irakense mutant was not able to grow on salicin but could still utilize arbutin, cellobiose, ...	1999	10321999
direct interaction of the epsl and epsm proteins of the general secretion apparatus in vibrio cholerae.	the general secretion pathway of gram-negative bacteria is responsible for extracellular secretion of a number of different proteins, including proteases and toxins. this pathway supports secretion of proteins across the cell envelope in two distinct steps, in which the second step, involving translocation through the outer membrane, is assisted by at least 13 different gene products. two of these components, the cytoplasmic membrane proteins epsl and epsm of vibrio cholerae, have been purified ...	1999	10322014
toward functional genomics in bacteria: analysis of gene expression in escherichia coli from a bacterial artificial chromosome library of bacillus cereus.	as the study of microbes moves into the era of functional genomics, there is an increasing need for molecular tools for analysis of a wide diversity of microorganisms. currently, biological study of many prokaryotes of agricultural, medical, and fundamental scientific interest is limited by the lack of adequate genetic tools. we report the application of the bacterial artificial chromosome (bac) vector to prokaryotic biology as a powerful approach to address this need. we constructed a bac libra ...	1999	10339608
enhancement of expression and apparent secretion of erwinia chrysanthemi endoglucanase (encoded by celz) in escherichia coli b.	escherichia coli b has been engineered as a biocatalyst for the conversion of lignocellulose into ethanol. previous research has demonstrated that derivatives of e. coli b can produce high levels of erwinia chrysanthemi endoglucanase (encoded by celz) as a periplasmic product and that this enzyme can function with commercial fungal cellulase to increase ethanol production. in this study, we have demonstrated two methods that improve celz expression in e. coli b. initially, with a low-copy-number ...	1999	10347024
cellobiose transport by mixed ruminal bacteria from a cow.	the transport of cellobiose in mixed ruminal bacteria harvested from a holstein cow fed an italian ryegrass hay was determined in the presence of nojirimycin-1-sulfate, which almost inhibited cellobiase activity. the kinetic parameters of cellobiose uptake were 14 microm for the km and 10 nmol/min/mg of protein for the vmax. extracellular and cell-associated cellobiases were detected in the rumen, with both showing higher vmax values and lower affinities than those determined for cellobiose tran ...	1999	10347044
regulation of hmp gene transcription in mycobacterium tuberculosis: effects of oxygen limitation and nitrosative and oxidative stress.	the mycobacterium tuberculosis hmp gene encodes a protein which is homologous to flavohemoglobin in escherichia coli. northern blotting analysis demonstrated that hmp transcription increased when a microaerophilic culture became oxygen limited as it entered stationary phase at 20 days. there was a fivefold increase of the hmp transcripts during early stationary phase compared with the value which was observed in the exponential growth phase. this induction of hmp transcription was not due to cha ...	1999	10348862
assembly of the type ii secretion machinery of erwinia chrysanthemi: direct interaction and associated conformational change between oute, the putative atp-binding component and the membrane protein outl.	erwinia chrysanthemi secretes, by the type ii secretory pathway, a large number of enzymes, including cellulases and pectinases. this process requires the products of the out genes, which are widely conserved in gram-negative bacteria. the out proteins are thought to form a membrane-associated multiprotein complex. here, we investigated interaction between oute, the putative atp binding component, and outl, an inner membrane protein. we showed, by limited proteolysis, genetic suppression and the ...	1999	10356336
the mdoc gene of escherichia coli encodes a membrane protein that is required for succinylation of osmoregulated periplasmic glucans.	osmoregulated periplasmic glucans (opgs) of escherichia coli are anionic oligosaccharides that accumulate in the periplasmic space in response to low osmolarity of the medium. their anionic character is provided by the substitution of the glucosidic backbone by phosphoglycerol originating from the membrane phospholipids and by succinyl residues from unknown origin. a phosphoglycerol-transferase-deficient mdob mutant was subjected to tn5 transposon mutagenesis, and putative mutant clones were scr ...	1999	10368134
the glucuronic acid utilization gene cluster from bacillus stearothermophilus t-6.	a lambda-embl3 genomic library of bacillus stearothermophilus t-6 was screened for hemicellulolytic activities, and five independent clones exhibiting beta-xylosidase activity were isolated. the clones overlap each other and together represent a 23.5-kb chromosomal segment. the segment contains a cluster of xylan utilization genes, which are organized in at least three transcriptional units. these include the gene for the extracellular xylanase, xylanase t-6; part of an operon coding for an intr ...	1999	10368143
modes of action of five different endopectate lyases from erwinia chrysanthemi 3937.	five endopectate lyases from the phytopathogenic bacterium erwinia chrysanthemi, pela, pelb, peld, peli, and pell, were analyzed with respect to their modes of action on polymeric and oligomeric substrates (degree of polymerization, 2 to 8). on polygalacturonate, pelb showed higher reaction rates than peld, peli, and pela, whereas the reaction rates for pell were extremely low. the product progression during polygalacturonate cleavage showed a typical depolymerization profile for each enzyme and ...	1999	10368144
structure of a plant cell wall fragment complexed to pectate lyase c.	the three-dimensional structure of a complex between the pectate lyase c (pelc) r218k mutant and a plant cell wall fragment has been determined by x-ray diffraction techniques to a resolution of 2.2 a and refined to a crystallographic r factor of 18.6%. the oligosaccharide substrate, alpha-d-galpa-([1-->4]-alpha-d-galpa)3-(1-->4)-d-galpa , is composed of five galacturonopyranose units (d-galpa) linked by alpha-(1-->4) glycosidic bonds. pelc is secreted by the plant pathogen erwinia chrysanthemi ...	1999	10368179
molecular characterization of a protease secreted by erwinia amylovora.	a protease with a molecular mass of 48 kda is secreted by the fire blight pathogen erwinia amylovora in minimal medium. we characterized this activity as a metalloprotease, since the enzyme was inhibited by edta and o -phenanthroline. a gene cluster was determined to encode four genes connected to protease expression, including a structural gene (prta) and three genes (prtd, prte, prtf) for secretion of the protease, which are transcribed in the same direction. the organization of the protease g ...	1999	10373365
the exopolygalacturonate lyase pelw and the oligogalacturonate lyase ogl, two cytoplasmic enzymes of pectin catabolism in erwinia chrysanthemi 3937.	erwinia chrysanthemi 3937 secretes into the external medium several pectinolytic enzymes, among which are eight isoenzymes of the endo-cleaving pectate lyases: pela, pelb, pelc, peld, and pele (family 1); peli (family 4); pell (family 3); and pelz (family 5). in addition, one exo-cleaving pectate lyase, pelx (family 3), has been found in the periplasm of e. chrysanthemi. the e. chrysanthemi 3937 gene kdgc has been shown to exhibit a high degree of similarity to the genes pely of yersinia pseudot ...	1999	10383957
elements involved in catabolite repression and substrate induction of the lactose operon in lactobacillus casei.	in lactobacillus casei atcc 393, the chromosomally encoded lactose operon, lactegf, encodes an antiterminator protein (lact), lactose-specific phosphoenolpyruvate-dependent phosphotransferase system (pts) elements (lace and lacf), and a phospho-beta-galactosidase. lact, lace, and lacf mutant strains were constructed by double crossover. the lact strain displayed constitutive termination at a ribonucleic antiterminator (rat) site, whereas lace and lacf mutants showed an inducer-independent antite ...	1999	10383959
membrane association and multimerization of secreton component pulc.	the pulc component of the klebsiella oxytoca pullulanase secretion machinery (the secreton) was found by subcellular fractionation to be associated with both the cytoplasmic (inner) and outer membranes. association with the outer membrane was independent of other secreton components, including the outer membrane protein puld (secretin). the association of pulc with the inner membrane is mediated by the signal anchor sequence located close to its n terminus. these results suggest that pulc forms ...	1999	10383968
structure-function analysis of xcpp, a component involved in general secretory pathway-dependent protein secretion in pseudomonas aeruginosa.	the general secretory pathway of pseudomonas aeruginosa is required for the transport of signal peptide-containing exoproteins across the cell envelope. after completion of the sec-dependent translocation of exoproteins across the inner membrane and cleavage of the signal peptide, the xcp machinery mediates translocation across the outer membrane. this machinery consists of 12 components, of which xcpq (gspd) is the sole outer membrane protein. xcpq forms a multimeric ring-shaped structure, with ...	1999	10383969
secretin puld: association with pilot puls, structure, and ion-conducting channel formation.	the outer membrane protein puld (secretin) of klebsiella oxytoca is required for transport of pullulanase across this membrane. we have purified a multimeric puld complex from an escherichia coli strain expressing all the proteins involved in pullulanase secretion. the outer membrane-anchored lipoprotein puls was found to copurify with puld. the molar ratio of the two proteins is close to 1:1, and the size of the complex is approximately 1 mda. scanning transmission electron and cryo-electron mi ...	1999	10393967
acquisition, transport, and storage of iron by pathogenic fungi.	iron is required by most living systems. a great variety of means of acquisition, avenues of uptake, and methods of storage are used by pathogenic fungi to ensure a supply of the essential metal. solubilization of insoluble iron polymers is the first step in iron assimilation. the two methods most commonly used by microorganisms for solubilization of iron are reduction and chelation. reduction of ferric iron to ferrous iron by enzymatic or nonenzymatic means is a common mechanism among pathogeni ...	1999	10398672
functional analysis of the carbohydrate-binding domains of erwinia chrysanthemi cel5 (endoglucanase z) and an escherichia coli putative chitinase.	the cel5 cellulase (formerly known as endoglucanase z) from erwinia chrysanthemi is a multidomain enzyme consisting of a catalytic domain, a linker region, and a cellulose binding domain (cbd). a three-dimensional structure of the cbd(cel5) has previously been obtained by nuclear magnetic resonance. in order to define the role of individual residues in cellulose binding, site-directed mutagenesis was performed. the role of three aromatic residues (trp18, trp43, and tyr44) in cellulose binding wa ...	1999	10419961
extracellular polysaccharide of erwinia chrysanthemi cu643.	erwinia chrysanthemi are gram-negative bacterial phytopathogens causing soft rots in a number of plants. the structure of the extracellular polysaccharide (eps) produced by e. chrysanthemi strain cu643, pathogenic to philodendron, has been determined using a combination of chemical and physical techniques including methylation analysis, high- and low-pressure gel-filtration and anion-exchange chromatography, high-ph anion-exchange chromatography, partial acid hydrolysis, mass spectrometry, and 1 ...	1999	10420593
cloning and sequencing of a high-alkaline pectate lyase gene from an alkaliphilic bacillus isolate.	alkaliphilic bacillus sp. strain ksm-p103 was found to exoproduce a high-alkaline pectate lyase (pectate transeliminase, ec 4.2.2.2). the gene for this enzyme from the alkaliphile was cloned and sequenced for the first time. the structural gene contained a 1,038-bp open reading frame encoding 345 amino acids. the deduced amino acid sequence of the mature enzyme (302 amino acids, 33,312 da), designated pel-103, showed very low similarity to those of known pectate lyases with 28-36% identity: the ...	1999	10427684
the xanthomonas hrp type iii system secretes proteins from plant and mammalian bacterial pathogens.	studies of essential pathogenicity determinants in gram-negative bacteria have revealed the conservation of type iii protein secretion systems that allow delivery of virulence factors into host cells from plant and animal pathogens. ten of 21 hrp proteins of the plant pathogen xanthomonas campestris pv. vesicatoria have been suggested to be part of a type iii machinery. here, we report the hrp-dependent secretion of two avirulence proteins, avrbs3 and avrrxv, by x. campestris pv. vesicatoria str ...	1999	10430949
the avr (effector) proteins hrma (hoppsya) and avrpto are secreted in culture from pseudomonas syringae pathovars via the hrp (type iii) protein secretion system in a temperature- and ph-sensitive manner.	we present here data showing that the avr proteins hrma and avrpto are secreted in culture via the native hrp pathways from pseudomonas syringae pathovars that produce these proteins. moreover, their secretion is strongly affected by the temperature and ph of the culture medium. both hrma and avrpto were secreted at their highest amounts when the temperature was between 18 and 22 degrees c and when the culture medium was ph 6.0. in contrast, temperature did not affect the secretion of hrpz. ph d ...	1999	10438746
the bvr locus of listeria monocytogenes mediates virulence gene repression by beta-glucosides.	the beta-glucoside cellobiose has been reported to specifically repress the prfa-dependent virulence genes hly and plca in listeria monocytogenes nctc 7973. this led to the hypothesis that beta-glucosides, sugars of plant origin, may act as signal molecules, preventing the expression of virulence genes if l. monocytogenes is living in its natural habitat (soil). in three other laboratory strains (egd, l028, and 10403s), however, the effect of cellobiose was not unique, and all fermentable carboh ...	1999	10438775
dsba is required for stable expression of outer membrane protein yscc and for efficient yop secretion in yersinia pestis.	the role of the periplasmic disulfide oxidoreductase dsba in yop secretion was investigated in yersinia pestis. a y. pestis dsba mutant secreted reduced amounts of the v antigen and yops and expressed reduced amounts of the full-sized yscc protein. site-directed mutagenesis of the four cysteine residues present in the yscc protein resulted in defects similar to those found in the dsba mutant. these results suggest that yscc contains at least one disulfide bond that is essential for the function ...	1999	10438793
erwinia carotovora has two kdgr-like proteins belonging to the icir family of transcriptional regulators: identification and characterization of the rexz activator and the kdgr repressor of pathogenesis.	a novel erwinia carotovora subsp. carotovora mutant designated rexz, (regulator of exoenzymes) showed reduced production of the degradative exoenzymes. the rexz gene product shows similarity of the kdgr regulatory protein from erwinia chrysanthemi, described as the major repressor of the pectin catabolism pathway genes in the latter species. in vitro dna-protein interaction experiments demonstrated that the synthesis of the rexz protein is controlled by the camp-crp (camp-receptor protein) compl ...	1999	10439393
genetic and biochemical characterization of an exopolygalacturonase and a pectate lyase from yersinia enterocolitica.	yersinia enterocolitica, an invasive foodborne human pathogen, degrades polypectate by producing two depolymerizing enzymes, pectate lyase (pl) and polygalacturonase (pg). the gene encoding the pg activity, designated pehy, was located in a 3-kb genomic fragment of y. enterocolitica atcc 49397. the complete nucleotide sequence of this 3-kb fragment was determined and an open reading frame consisting of 1803 bp was predicted to encode a pg protein with an estimated m(r) of 66 kda and pi of 6.3. t ...	1999	10446714
engineering endoglucanase-secreting strains of ethanologenic klebsiella oxytoca p2.	recombinant klebsiella oxytoca p2 was developed as a biocatalyst for the simultaneous saccharification and fermentation (ssf) of cellulose by chromosomally integrating zymomonas mobilis genes (pdc, adhb) encoding the ethanol pathway. this strain contains the native ability to transport and metabolize cellobiose, eliminating the need to supplement with beta-glucosidase during ssf. to increase the utility of this biocatalyst, we have now chromosomally integrated the celz gene encoding the primary ...	1999	10455486
isolation of an extracellular protease gene of erwinia carotovora subsp. carotovora strain scc3193 by transposon mutagenesis and the role of protease in phytopathogenicity.	using mini-tn5cmr::gusa, a transposon that allows transcriptional fusions to a promoterless beta-glucuronidase gene, a mutant of erwinia carotovora subsp. carotovora scc3193 deficient in extracellular protease production and soft-rot pathogenicity in plants was isolated. the mutant, designated scc6004, produced normal levels of pectate lyase, polygalacturonase and cellulase. the region of the transposon insertion was partially sequenced to permit the design of specific oligonucleotide primers to ...	1999	10463162
a new class of cobalamin transport mutants (btuf) provides genetic evidence for a periplasmic binding protein in salmonella typhimurium.	no periplasmic binding protein has been demonstrated for the atp-binding cassette (abc)-type cobalamin transporter btucd. new mutations (btuf) are described that affect inner-membrane transport. the btuf protein has a signal sequence and resembles the periplasmic binding proteins of several other abc transporters.	1999	10464235
purification and characterization of an extracellular protease from the fish pathogen yersinia ruckeri and effect of culture conditions on production.	a novel protease, hydrolyzing azocasein, was identified, purified, and characterized from the culture supernatant of the fish pathogen yersinia ruckeri. exoprotease production was detected at the end of the exponential growth phase and was temperature dependent. activity was detected in peptone but not in casamino acid medium. its synthesis appeared to be under catabolite repression and ammonium control. the protease was purified in a simple two-step procedure involving ammonium sulfate precipit ...	1999	10473403
characterization of an acetyl xylan esterase from the anaerobic fungus orpinomyces sp. strain pc-2.	a 1,067-bp cdna, designated axea, coding for an acetyl xylan esterase (axea) was cloned from the anaerobic rumen fungus orpinomyces sp. strain pc-2. the gene had an open reading frame of 939 bp encoding a polypeptide of 313 amino acid residues with a calculated mass of 34,845 da. an active esterase using the original start codon of the cdna was synthesized in escherichia coli. two active forms of the esterase were purified from recombinant e. coli cultures. the size difference of 8 amino acids w ...	1999	10473406
development and application of pathovar-specific monoclonal antibodies that recognize the lipopolysaccharide o antigen and the type iv fimbriae of xanthomonas hyacinthi.	the objective of this study was to develop a specific immunological diagnostic assay for yellow disease in hyacinths, using monoclonal antibodies (mabs). mice were immunized with a crude cell wall preparation (shear fraction) from xanthomonas hyacinthi and with purified type iv fimbriae. hybridomas were screened for a positive reaction with x. hyacinthi cells or fimbriae and for a negative reaction with x. translucens pv. graminis or erwinia carotovora subsp. carotovora. nine mabs recognized fim ...	1999	10473431
differential protease-mediated turnover of h-ns and stpa revealed by a mutation altering protein stability and stationary-phase survival of escherichia coli.	the escherichia coli proteins h-ns is recognized as an important component among the major nucleoid-associated proteins. in studies of e. coli strains with defects in h-ns, we discovered a mutant that phenotypically restored stationary-phase viability (rsv) of such strains. the rsv phenotype was the result of a mutation that led to severalfold higher levels of the functionally and structurally related stpa protein. this mutation was a base pair change in the stpa structural gene, and the amino a ...	1999	10485902
regulation of peld and pele, encoding major alkaline pectate lyases in erwinia chrysanthemi: involvement of the main transcriptional factors.	the main virulence factors of the phytopathogenic bacterium erwinia chrysanthemi are pectinases which attack pectin, the major constituent of the plant cell wall. of these enzymes, the alkaline isoenzyme named peld in strain 3937 and pele in strain ec16 has been described as being particularly important, based on virulence studies of plants. expression of the peld and pele genes is tightly modulated by various regulators, including the kdgr repressor and the cyclic amp-cyclic amp receptor protei ...	1999	10498706
rsmc of the soft-rotting bacterium erwinia carotovora subsp. carotovora negatively controls extracellular enzyme and harpin(ecc) production and virulence by modulating levels of regulatory rna (rsmb) and rna-binding protein (rsma).	previous studies have shown that the production of extracellular enzymes (pectate lyase [pel], polygalacturonase [peh], cellulase [cel], and protease [prt]) and harpin(ecc) (the elicitor of hypersensitive reaction) in erwinia carotovora subsp. carotovora is regulated by rsma, an rna-binding protein, and rsmb, a regulatory rna (rsm stands for regulator of secondary metabolites) (y. liu et al., mol. microbiol. 29:219-234, 1998). we have cloned and characterized a novel regulatory gene, rsmc, that ...	1999	10498717
mutational analysis of the recj exonuclease of escherichia coli: identification of phosphoesterase motifs.	the recj gene, identified in escherichia coli, encodes a mg(+2)-dependent 5'-to-3' exonuclease with high specificity for single-strand dna. genetic and biochemical experiments implicate recj exonuclease in homologous recombination, base excision, and methyl-directed mismatch repair. genes encoding proteins with strong similarities to recj have been found in every eubacterial genome sequenced to date, with the exception of mycoplasma and mycobacterium tuberculosis. multiple genes encoding protein ...	1999	10498723
the three asparaginases. comparative pharmacology and optimal use in childhood leukemia.	asparaginase (asp) is a standard component of the antileukemia armamentarium. there are currently 3 preparations of asparaginase available: (1) e. coli (asp, elspar); (2) the enzyme derived from erwinia chrysanthemi (erw, erwinase); (3) pegaspargase (peg, oncaspar), the e. coli enzyme modified by covalent attachment of polyethylene glycol. this report describes the findings of 3 pharmacologic end points: asp enzyme activity in patients' sera, depletion of asparagine and the development of anti-a ...	1999	10500842
opening the iron box: transcriptional metalloregulation by the fur protein.		1999	10515908
ferric enterochelin transport in yersinia enterocolitica: molecular and evolutionary aspects.	yersinia enterocolitica is well equipped for siderophore piracy, encompassing the utilization of siderophores such as ferrioxamine, ferrichrome, and ferrienterochelin. in this study, we report on the molecular and functional characterization of the yersinia fep-fes gene cluster orthologous to the escherichia coli ferrienterochelin transport genes (fepa, fepdgc, and fepb) and the esterase gene fes. in vitro transcription-translation analysis identified polypeptides of 30 and 35 kda encoded by fep ...	1999	10515929
effectors of a developmental mitogen-activated protein kinase cascade revealed by expression signatures of signaling mutants.	despite the importance of mitogen-activated protein kinase (mapk) signaling in eukaryotic biology, the mechanisms by which signaling yields phenotypic changes are poorly understood. we have combined transcriptional profiling with genetics to determine how the kss1 mapk signaling pathway controls dimorphic development in saccharomyces cerevisiae. this analysis identified dozens of transcripts that are regulated by the pathway, whereas previous work had identified only a single downstream target, ...	1999	10535956
reciprocal secretion of proteins by the bacterial type iii machines of plant and animal pathogens suggests universal recognition of mrna targeting signals.	bacterial pathogens of both animals and plants use type iii secretion machines to inject virulence proteins into host cells. although many components of the secretion machinery are conserved among different bacterial species, the substrates for their type iii pathways are not. the yersinia type iii machinery recognizes some secretion substrates via a signal that is encoded within the first 15 codons of yop mrna. these signals can be altered by frameshift mutations without affecting secretion of ...	1999	10536009
distribution of tetracycline resistance genes and transposons among phylloplane bacteria in michigan apple orchards.	the extent and nature of tetracycline resistance in bacterial populations of two apple orchards with no or a limited history of oxytetracycline usage were assessed. tetracycline-resistant (tc(r)) bacteria were mostly gram negative and represented from 0 to 47% of the total bacterial population on blossoms and leaves (versus 26 to 84% for streptomycin-resistant bacteria). a total of 87 isolates were screened for the presence of specific tc(r) determinants. tc(r) was determined to be due to the pr ...	1999	10543801
analysis of three clustered polygalacturonase genes in erwinia chrysanthemi 3937 revealed an anti-repressor function for the pecs regulator.	erwinia chrysanthemi 3937 secretes an arsenal of pectinolytic enzymes including several pectate lyases encoded by the pel genes. we characterized a novel cluster of pectinolytic genes consisting of the three adjacent genes pehv, pehw and pehx, whose products have polygalacturonase activity. the high similarity between the three genes suggests that they result from duplication of an ancestral gene. the transcription of pehv, pehw and pehx is dependent on several environmental conditions. they are ...	1999	10564505
genetic dissection of the outer membrane secretin puld: are there distinct domains for multimerization and secretion specificity?	linker and deletion mutagenesis and gene fusions were used to probe the possible domain structure of the dodecameric outer membrane secretin puld from the pullulanase secretion pathway of klebsiella oxytoca. insertions of 24 amino acids close to or within strongly predicted and highly conserved amphipathic beta strands in the c-terminal half of the polypeptide (the beta domain) abolished sodium dodecyl sulfate (sds)-resistant multimer formation that is characteristic of this protein, whereas ins ...	1999	10572123
a unique chitinase with dual active sites and triple substrate binding sites from the hyperthermophilic archaeon pyrococcus kodakaraensis kod1.	we have found that the hyperthermophilic archaeon pyrococcus kodakaraensis kod1 produces an extracellular chitinase. the gene encoding the chitinase (chia) was cloned and sequenced. the chia gene was found to be composed of 3,645 nucleotides, encoding a protein (1,215 amino acids) with a molecular mass of 134,259 da, which is the largest among known chitinases. sequence analysis indicates that chia is divided into two distinct regions with respective active sites. the n-terminal and c-terminal r ...	1999	10583986
requirement for phosphoglucose isomerase of xanthomonas campestris in pathogenesis of citrus canker.	a mutant (xt906) of xanthomonas campestris pv. citri, the causal agent of citrus canker, was induced by insertion of the transposon tn5tac1 and isolated. this mutant did not grow or elicit canker disease in citrus leaves but was still able to induce a hypersensitive response in a nonhost plant (the common bean). the mutant was also unable to grow on minimal medium containing fructose or glycerol as the sole carbon source. a 2.5-kb fragment of wild-type dna that complemented the mutant phenotype ...	1999	10584018
genetic analysis of a chromosomal region containing genes required for assimilation of allantoin nitrogen and linked glyoxylate metabolism in escherichia coli.	growth experiments with escherichia coli have shown that this organism is able to use allantoin as a sole nitrogen source but not as a sole carbon source. nitrogen assimilation from this compound was possible only under anaerobic conditions, in which all the enzyme activities involved in allantoin metabolism were detected. of the nine genes encoding proteins required for allantoin degradation, only the one encoding glyoxylate carboligase (gcl), the first enzyme of the pathway leading to glycerat ...	1999	10601204
cloning and characterization of the pseudomonas fluorescens atp-binding cassette exporter, hasdef, for the heme acquisition protein hasa.	two atp-binding cassette (abc) exporters are present in pseudomonas fluorescens no. 33; one is the recently reported aprdef system and the other is hasdef, which exports a heme acquisition protein, hasa. the hasdef genes were cloned by dna hybridization with a dna probe coding for the lipb protein, one of the components of the serratia marcescens abc exporter lip system. p. fluorescens hasa showed sequence identity of 40 to 49% with hasa proteins from pseudomonas aeruginosa and serratia marcesce ...	1999	10601212
a multifunctional atp-binding cassette transporter system from vibrio cholerae transports vibriobactin and enterobactin.	vibrio cholerae uses the catechol siderophore vibriobactin for iron transport under iron-limiting conditions. we have identified genes for vibriobactin transport and mapped them within the vibriobactin biosynthetic gene cluster. within this genetic region we have identified four genes, viup, viud, viug and viuc, whose protein products have homology to the periplasmic binding protein, the two integral cytoplasmic membrane proteins, and the atpase component, respectively, of other iron transport s ...	1999	10601218
performance of selected microbial pectinases on synthetic monomethyl-esterified di- and trigalacturonates.	two monomethyl esters of alpha-(1-4)-linked d-galacturonic dimers and three monomethyl esters of alpha-(1-4)-linked d-galacturonic acid trimers were synthesized chemically and further used as substrates in order to establish the substrate specificity of six different endopolygalacturonases from aspergillus niger, one exopolygalacturonase from aspergillus tubingensis, and four selected erwinia chrysanthemi pectinases; exopolygalacturonan hydrolase x (pehx), exopolygalacturonate lyase x (pelx), ex ...	1999	10601263
withholding and exchanging iron: interactions between erwinia spp. and their plant hosts.	the critical role of iron in plant host-parasite relationships has been elucidated in diseases as different as the soft rot and fire blight incited by erwinia chrysanthemi and e. amylovora, respectively. as in animal infections, the role of iron and its ligands in the virulence of plant pathogens seems to be more subtle than might be expected, and is intimately related to the life cycle of the pathogen within its host. this review discusses how iron, because of its unique position in biological ...	1999	11701826
fungal resistance to plant antibiotics as a mechanism of pathogenesis.	many plants produce low-molecular-weight compounds which inhibit the growth of phytopathogenic fungi in vitro. these compounds may be preformed inhibitors that are present constitutively in healthy plants (also known as phytoanticipins), or they may be synthesized in response to pathogen attack (phytoalexins). successful pathogens must be able to circumvent or overcome these antifungal defenses, and this review focuses on the significance of fungal resistance to plant antibiotics as a mechanism ...	1999	10477313
bacterial quorum sensing in pathogenic relationships.		2000	10948095
transcriptional regulation of transport and utilization systems for hexuronides, hexuronates and hexonates in gamma purple bacteria.	the comparative approach is a powerful tool for the analysis of gene regulation in bacterial genomes. it can be applied to the analysis of regulons that have been studied experimentally as well as that of regulons for which no known regulatory sites are available. it is assumed that the set of co-regulated genes and the regulatory signal itself are conserved in related genomes. here, we use genomic comparisons to study the regulation of transport and utilization systems for sugar acids in gamma ...	2000	11115104
cloning and characterization of thermostable endoglucanase (cel8y) from the hyperthermophilic aquifex aeolicus vf5.	aquifex aeolicus is the hyperthermophilic bacterium known, with growth-temperature maxima near 95 degrees c. the cel8y gene, encoding a thermostable endoglucanase (cel8y) from aquifex aeolicus vf5, was cloned into a vector for expression and expressed in escherichia coli xl1-blue. a clone of 1.7 kb fragment containing endoglucanase activity, designated pkycy100, was sequenced and found to contain an orf of 978 bp encoding a protein of 325 amino acid residues, with a calculated molecular mass of ...	2000	11118302
from rags to riches: insights from the first genomic sequence of a plant pathogenic bacterium.	the recently published genomic sequence of xylella fastidiosa is the first for a free-living plant pathogen and provides clues to mechanisms of pathogenesis and survival in insect vectors. the sequence data should lead to improved control of this pathogen.	2000	11178244
chunnel vision. export and efflux through bacterial channel-tunnels.	the escherichia coli tolc protein is central to toxin export and drug efflux across the inner and outer cell membranes and the intervening periplasmic space. the crystal structure has revealed that tolc assembles into a remarkable alpha-helical trans-periplasmic cylinder (tunnel) embedded in the outer membrane by a contiguous beta-barrel (channel), so providing a large duct open to the outside environment. the channel-tunnel structure is conserved in tolc homologues throughout gram-negative bact ...	2000	11269495
glycine betaine transport in lactococcus lactis is osmotically regulated at the level of expression and translocation activity.	microorganisms react upon hyperosmotic stress by accumulating compatible solutes. here we report that lactococcus lactis uses a transport system for glycine betaine that, contrary to earlier observations (d. molenaar et al., j. bacteriol. 175:5438-5444, 1993), is osmotically regulated at the levels of both expression and transport activity.	2000	10613881
expression of alcaligenes eutrophus flavohemoprotein and engineered vitreoscilla hemoglobin-reductase fusion protein for improved hypoxic growth of escherichia coli.	expression of the vhb gene encoding hemoglobin from vitreoscilla sp. (vhb) in several organisms has been shown to improve microaerobic cell growth and enhance oxygen-dependent product formation. the amino-terminal hemoglobin domain of the flavohemoprotein (fhp) of the gram-negative hydrogen-oxidizing bacterium alcaligenes eutrophus has 51% sequence homology with vhb. however, like other flavohemoglobins and unlike vhb, fhp possesses a second (carboxy-terminal) domain with nad(p)h and flavin aden ...	2000	10618209
alteration of the lipopolysaccharide structure affects the functioning of the xcp secretory system in pseudomonas aeruginosa.	pseudomonas aeruginosa secretes a wide range of hydrolytic enzymes into the external medium by the xcp secretion machinery. to better understand the role played by envelope constituents in the functioning of this type ii secretory system, we have studied the influence of lipopolysaccharide (lps) on the secretion of two extracellular enzymes, the elastase lasb and the lipase lipa. strains with defective lps decreased production of lasb and altered the secretion processes of both lasb and lipa wit ...	2000	10633103
two regions of epsl involved in species-specific protein-protein interactions with epse and epsm of the general secretion pathway in vibrio cholerae.	extracellular secretion of proteins via the type ii or general secretion pathway in gram-negative bacteria requires the assistance of at least 12 gene products that are thought to form a complex apparatus through which secreted proteins are translocated. although this apparatus is specifically required only for the outer membrane translocation step during transport across the bacterial cell envelope, it is believed to span both membranes. the epse, epsl, and epsm proteins of the type ii apparatu ...	2000	10633109
discovery of a nonclassical siderophore, legiobactin, produced by strains of legionella pneumophila.	the mechanisms by which legionella pneumophila, a facultative intracellular parasite and the agent of legionnaires' disease, acquires iron are largely unexplained. several earlier studies indicated that l. pneumophila does not elaborate siderophores. however, we now present evidence that supernatants from l. pneumophila cultures can contain a nonproteinaceous, high-affinity iron chelator. more specifically, when aerobically grown in a low-iron, chemically defined medium (cdm), l. pneumophila sec ...	2000	10633110
conversion of the vibrio fischeri transcriptional activator, luxr, to a repressor.	the vibrio fischeri luminescence (lux) operon is regulated by a quorum-sensing system that involves the transcriptional activator (luxr) and an acyl-homoserine lactone signal. transcriptional activation requires the presence of a 20-base inverted repeat termed the lux box at a position centered 42.5 bases upstream of the transcriptional start of the lux operon. luxr has proven difficult to study in vitro. a truncated form of luxr has been purified, and together with sigma(70) rna polymerase it c ...	2000	10633117
a gene encoding a novel multidomain beta-1,4-mannanase from caldibacillus cellulovorans and action of the recombinant enzyme on kraft pulp.	genomic walking pcr was used to obtained a 4,567-bp nucleotide sequence from caldibacillus cellulovorans. analysis of this sequence revealed that there were three open reading frames, designated orf1, orf2, and orf3. incomplete orf1 encoded a putative c-terminal cellulose-binding domain (cbd) homologous to members of cbd family iiib, while putative orf3 encoded a protein of unknown function. the putative mana protein encoded by complete mana orf2 was an enzyme with a novel multidomain structure ...	2000	10653733
an unusual pectate lyase from a bacillus sp. with high activity on pectin: cloning and characterization.	the gene pela encoding a pectate lyase from the strain bacillus sp. bp-23 was cloned and expressed in escherichia coli. the nucleotide sequence of a 1214 bp dna fragment containing pela gene was determined, revealing an orf of 666 nucleotides that encoded a protein of 23233 da. the deduced amino acid sequence of the encoded enzyme showed homology to pectate lyases a, b, c and d from fusarium solani, pel-3 and pelb from erwinia carotovora and pell from erwinia chrysanthemi. homology was also foun ...	2000	10658655
the cochliobolus carbonum snf1 gene is required for cell wall-degrading enzyme expression and virulence on maize.	the production of cell wall-degrading enzymes (wall depolymerases) by plant pathogenic fungi is under catabolite (glucose) repression. in saccharomyces cerevisiae, the snf1 gene is required for expression of catabolite-repressed genes when glucose is limiting. an ortholog of snf1, ccsnf1, was isolated from the maize pathogen cochliobolus carbonum, and ccsnf1 mutants of hc toxin-producing (tox2(+)) and hc toxin-nonproducing (tox2(-)) strains were created by targeted gene replacement. growth in vi ...	2000	10662860
characterization of sota and sotb, two erwinia chrysanthemi proteins which modify isopropyl-beta-d-thiogalactopyranoside and lactose induction of the escherichia coli lac promoter.	the expression, in escherichia coli, of variants of the erwinia chrysanthemi secretion genes outb and outs under the ptac promoter is toxic to the cells. during attempts to clone e. chrysanthemi genes able to suppress this toxicity, i identified two genes, sota and sotb, whose products are able to reduce the isopropyl-beta-d-thiogalactopyranoside (iptg) induction of the e. coli lac promoter. sota and sotb belong to two different families of the major facilitator superfamily. sota is a member of ...	2000	10671456
characterization of erwinia chrysanthemi py35 cel and pel gene existing in tandem and rapid identification of their gene products.	genomic dna of the phytopathogenic erwinia chrysanthemi py35 was partially digested with sau3ai, ligated into the bamhi site of pbluescript ii sk+, and introduced into e. coli. one clone that was able to hydrolyse carboxymethylcellulose and polygalacturonic acid was selected. a 2.9 kb fragment containing the pell1 gene (ppy300) and cel5z gene (ppy401) in tandem was subcloned and sequenced. the pell1 and cel5z genes had open reading frames of 1,278 bp and 1,281 bp encoding 425 and 426 amino acid ...	2000	10679220
association of the cytoplasmic membrane protein xpsn with the outer membrane protein xpsd in the type ii protein secretion apparatus of xanthomonas campestris pv. campestris.	an xps gene cluster composed of 11 open reading frames is required for the type ii protein secretion in xanthomonas campestris pv. campestris. immediately upstream of the xpsd gene, which encodes an outer membrane protein that serves as the secretion channel by forming multimers, there exists an open reading frame (previously designated orf2) that could encode a protein of 261 amino acid residues. its n-terminal hydrophobic region is a likely membrane-anchoring sequence. antibody raised against ...	2000	10692359
ssra (tmrna) plays a role in salmonella enterica serovar typhimurium pathogenesis.	escherichia coli ssra encodes a small stable rna molecule, tmrna, that has many diverse functions, including tagging abnormal proteins for degradation, supporting phage growth, and modulating the activity of dna binding proteins. here we show that ssra plays a role in salmonella enterica serovar typhimurium pathogenesis and in the expression of several genes known to be induced during infection. moreover, the phage-like attachment site, attl, encoded within ssra, serves as the site of integratio ...	2000	10692360
ph regulation of pectate lyase secretion modulates the attack of colletotrichum gloeosporioides on avocado fruits.	growth of colletotrichum gloeosporioides in pectolytic enzyme-inducing medium (peim) increased the ph of the medium from 3. 8 to 6.5. pectate lyase (pl) secretion was detected when the ph reached 5.8, and the level of secretion increased up to ph 6.5. pl gene (pel) transcript production began at ph 5.0 and increased up to ph 5.7. pl secretion was never detected when the ph of the inducing medium was lower than 5.8 or when c. gloeosporioides hyphae were transferred from pl-secreting conditions at ...	2000	10698767
transformation of acinetobacter sp. strain bd413(pfg4deltanptii) with transgenic plant dna in soil microcosms and effects of kanamycin on selection of transformants.	here we show that horizontal transfer of dna, extracted from transgenic sugar beets, to bacteria, based on homologous recombination, can occur in soil. restoration of a 317-bp-deleted nptii gene in acinetobacter sp. strain bd413(pfg4) cells incubated in sterile soil microcosms was detected after addition of nutrients and transgenic plant dna encoding a functional nptii gene conferring bacterial kanamycin resistance. selective effects of the addition of kanamycin on the population dynamics of aci ...	2000	10698801
microbial relatives of the seed storage proteins of higher plants: conservation of structure and diversification of function during evolution of the cupin superfamily.	this review summarizes the recent discovery of the cupin superfamily (from the latin term "cupa," a small barrel) of functionally diverse proteins that initially were limited to several higher plant proteins such as seed storage proteins, germin (an oxalate oxidase), germin-like proteins, and auxin-binding protein. knowledge of the three-dimensional structure of two vicilins, seed proteins with a characteristic beta-barrel core, led to the identification of a small number of conserved residues a ...	2000	10704478
purification, crystallization and x-ray analysis of crystals of pectate lyase a from exwinia chrysanthemi.	pectate lyase a is secreted by erwinia chrysanthemi and is a virulence factor for soft rot diseases in plants. crystals of pectate lyase a were obtained by vapor-diffusion techniques in the presence of polyethylene glycol. the crystals belong to the monoclinic space group p2(1), with unit-cell parameters a = 48.96, b = 148.86, c = 78.61 a, beta = 97.32 degrees. the crystals contain two protein molecules of 38 kda per asymmetric unit and diffract to 2.4 a using cu kalpha radiation.	2000	10713524
aiia, an enzyme that inactivates the acylhomoserine lactone quorum-sensing signal and attenuates the virulence of erwinia carotovora.	n-acylhomoserine lactones, known as autoinducers (ais), are widely conserved signal molecules present in quorum-sensing systems of many gram-negative bacteria. ais are involved in the regulation of diverse biological functions, including expression of pathogenic genes in the plant pathogens pseudomonas solanacearum, several erwinia species, and the human pathogen pseudomonas aeruginosa. a bacterial isolate, bacillus sp. 240b1, is capable of enzymatic inactivation of ais. the gene (aiia) for ai i ...	2000	10716724
secreted enzymatic activities of wild-type and pild-deficient legionella pneumophila.	legionella pneumophila, the agent of legionnaires' disease, is an intracellular pathogen of protozoa and macrophages. previously, we had determined that the legionella pild gene is involved in type iv pilus biogenesis, type ii protein secretion, intracellular infection, and virulence. since the loss of pili and a protease do not account for the infection defect exhibited by a pild-deficient strain, we sought to define other secreted proteins absent in the mutant. based upon the release of p-nitr ...	2000	10722574
mutations in the extracellular protein secretion pathway genes (eps) interfere with rugose polysaccharide production in and motility of vibrio cholerae.	vibrio cholerae is the causal organism of the diarrheal disease cholera. the rugose variant of v. cholerae is associated with the secretion of an exopolysaccharide. the rugose polysaccharide has been shown to confer increased resistance to a variety of agents, such as chlorine, bioacids, and oxidative and osmotic stresses. it also promotes biofilm formation, thereby increasing the survival of the bacteria in the aquatic environments. here we show that the extracellular protein secretion system ( ...	2000	10722590
identification of regions of the escherichia coli chromosome specific for neonatal meningitis-associated strains.	specific virulence factors associated with the pathogenesis of escherichia coli strains causing neonatal meningitis (ecnm), such as the k1 capsular polysaccharide, the s fimbriae, and the ibe10 protein, have been previously identified. however, some other yet unidentified factors are likely to be involved in the pathogenesis of ecnm. to identify specialized unique dna regions associated with ecnm virulence, we used the representational difference analysis technique. the genomes of two strains be ...	2000	10722606
the phytopathogenic bacteria erwinia carotovora infects drosophila and activates an immune response.	although drosophila possesses potent immune responses, little is known about the microbial pathogens that infect drosophila. we have identified members of the bacterial genus erwinia that induce the systemic expression of genes encoding antimicrobial peptides in drosophila larvae after ingestion. these erwinia strains are phytopathogens and use flies as vectors; our data suggest that these strains have also evolved mechanisms for exploiting their insect vectors as hosts. erwinia infections induc ...	2000	10725405
multiple interactions between pullulanase secreton components involved in stabilization and cytoplasmic membrane association of pule.	we report attempts to analyze interactions between components of the pullulanase (pul) secreton (type ii secretion machinery) from klebsiella oxytoca encoded by a multiple-copy-number plasmid in escherichia coli. three of the 15 pul proteins (b, h, and n) were found to be dispensable for pullulanase secretion. the following evidence leads us to propose that pule, pull, and pulm form a subcomplex with which pulc and pulg interact. the integral cytoplasmic membrane protein pull prevented proteolys ...	2000	10735856
identification of an operon required for ferrichrome iron utilization in vibrio cholerae.	mutagenesis of vibrio cholerae with tnphoa, followed by screening for fusions that were activated under low-iron conditions, led to the identification of seven independent fusion strains, each of which was deficient in the ability to utilize ferrichrome as a sole iron source for growth in a plate bioassay and had an insertion in genes encoding products homologous to escherichia coli fhua or fhud. expression of the gene fusions was independent of irgb but regulated by fur. we report here a map of ...	2000	10735886
production of pectate lyases and cellulases by chryseomonas luteola strain mfcl0 depends on the growth temperature and the nature of the culture medium: evidence for two critical temperatures.	several extracellular enzymes that are responsible for plant tissue maceration were detected in culture supernatant of the psychrotrophic bacterium chryseomonas luteola mfcl0. isoelectrofocusing experiments showed that pectate lyase (pl) activity resulted from the cumulative action of three major isoenzymes, designated pli, plii, and pliii. cellulolytic activity was also detected in culture supernatants. these enzymes exhibited different behaviors with respect to growth temperature. plii was not ...	2000	10742239
role of molybdate and other transition metals in the accumulation of protochelin by azotobacter vinelandii.	both molybdate and iron are metals that are required by the obligately aerobic organism azotobacter vinelandii to survive in the nutrient-limited conditions of its natural soil environment. previous studies have shown that a high concentration of molybdate (1 mm) affects the formation of a. vinelandii siderophores such that the tricatecholate protochelin is formed to the exclusion of the other catecholate siderophores, azotochelin and aminochelin. it has been shown previously that molybdate comb ...	2000	10742245
extracellular polysaccharide of erwinia chrysanthemi a350 and ribotyping of erwinia chrysanthemi spp.	erwinia chrysanthemi spp. are gram-negative bacterial phytopathogens causing soft rots in a number of plants. the structure of the extracellular polysaccharide (eps) produced by the e. chrysanthemi strain a350, which is a lacz- mutant of the wild type strain 3937, pathogenic to saintpaulia, has been determined using a combination of chemical and physical techniques including methylation analysis, low-pressure gel-filtration and anion-exchange chromatography, high-ph anion-exchange chromatography ...	2000	10744334
overproduction of the secretin outd suppresses the secretion defect of an erwinia chrysanthemi outb mutant.	outb is a component of the erwinia chrysanthemi out secretion machinery. homologues of outb have been described in two other bacteria, klebsiella oxytoca and aeromonas hydrophila, but their requirement in the secretion process seems to be different. study of outb topology with the blam topology probe suggests that it is an inner-membrane protein with a large periplasmic domain. however, fractionation experiments indicate that it could be associated with the outer membrane through its c-terminal ...	2000	10746767
quorum sensing in the plant pathogen erwinia carotovora subsp. carotovora: the role of expr(ecc).	the production of the main virulence determinants of the plant pathogen erwinia carotovora subsp. carotovora, the extracellular cell wall-degrading enzymes, is partly controlled by the diffusible signal molecule n-(3-oxohexanoyl)-l-homoserine lactone (ohhl). ohhl is synthesized by the product of the expi/cari gene. linked to expi we found a gene encoding a putative transcriptional regulator of the luxr-family. this gene, expr(ecc), is transcribed convergently to the expi gene and the two open re ...	2000	10755301
evidence against a direct antimicrobial role of h2o2 in the infection of plants by erwinia chrysanthemi.	we have investigated the role of bacterial resistance to oxidative stress in pathogenesis. the oxyr gene from the pathogenic bacterium erwinia chrysanthemi has been characterized. it is closely related to that found in escherichia coli (88% overall amino acid identity). an e. chrysanthemi oxyr mutant strain was constructed by marker exchange. after induction with a sublethal dose of h2o2, this mutant was more sensitive to h2o2 and showed reduced levels of catalase and glutathione reductase activ ...	2000	10755305
protection from nitrosative stress by yeast flavohemoglobin.	yeast hemoglobin was discovered close to half a century ago, but its function has remained unknown. herein, we report that this flavohemoglobin protects saccharomyces cerevisiae from nitrosative stress. deletion of the flavohemoglobin gene (yhb1) abolished the nitric oxide (no)-consuming activity of yeast cells. levels of protein nitrosylation were more than 10-fold higher in yhb1 mutant yeast than in isogenic wild-type cells after incubation with no donors. growth of mutant cells was inhibited ...	2000	10758168
the pseudomonas syringae hrp pathogenicity island has a tripartite mosaic structure composed of a cluster of type iii secretion genes bounded by exchangeable effector and conserved effector loci that contribute to parasitic fitness and pathogenicity in plants.	the plant pathogenic bacterium pseudomonas syringae is divided into pathovars differing in host specificity, with p. syringae pv. syringae (psy) and p. syringae pv. tomato (pto) representing particularly divergent pathovars. p. syringae hrp/hrc genes encode a type iii protein secretion system that appears to translocate avr and hop effector proteins into plant cells. dna sequence analysis of the hrp/hrc regions in psy 61, psy b728a, and pto dc3000 has revealed a hrp pathogenicity island (pai) wi ...	2000	10781092
solution structure of the chitin-binding domain of bacillus circulans wl-12 chitinase a1.	the three-dimensional structure of the chitin-binding domain (chbd) of chitinase a1 (chia1) from a gram-positive bacterium, bacillus circulans wl-12, was determined by means of multidimensional heteronuclear nmr methods. chia1 is a glycosidase that hydrolyzes chitin and is composed of an n-terminal catalytic domain, two fibronectin type iii-like domains, and c-terminal chbd(chia1) (45 residues, ala(655)-gln(699)), which binds specifically to insoluble chitin. chbd(chia1) has a compact and globul ...	2000	10788483
a fluorometric assay for l-asparaginase activity and monitoring of l-asparaginase therapy.	the antineoplastic enzyme l-asparaginase is commonly used for the induction of remission in acute lymphoblastic leukemia (all). there is no simple method available for measuring the activity of this highly toxic drug. we incubated l-asparaginase from erwinia chrysanthemi with l-aspartic acid beta-(7-amido-4-methylcoumarin) and measured the release of 7-amino-4-methylcoumarin fluorometrically for 30-300 min. the rate of the hydrolysis of the substrate was linear over a 50-fold range of the concen ...	2000	10805519
differential regulation of plastidial and cytosolic isoforms of peptide methionine sulfoxide reductase in arabidopsis.	we report the characterization of two members of a gene family from arabidopsis that encode, respectively, cytosolic (cpmsr) and plastid-targeted (ppmsr) isoforms of the oxidative-stress-repair enzyme peptide methionine sulfoxide reductase. overexpression of these proteins in escherichia coli confirmed that each had pmsr enzyme activity with a synthetic substrate, n-acetyl-[(3)h]-methionine sulfoxide, or a biological substrate, alpha-1 proteinase inhibitor. the ppmsr was imported into intact chl ...	2000	10806242
expression and characterization of the chitin-binding domain of chitinase a1 from bacillus circulans wl-12.	chitinase a1 from bacillus circulans wl-12 comprises an n-terminal catalytic domain, two fibronectin type iii-like domains, and a c-terminal chitin-binding domain (chbd). in order to study the biochemical properties and structure of the chbd, chbd(chia1) was produced in escherichia coli using a pet expression system and purified by chitin affinity column chromatography. purified chbd(chia1) specifically bound to various forms of insoluble chitin but not to other polysaccharides, including chitos ...	2000	10809681
secretion of the caulobacter crescentus s-layer protein: further localization of the c-terminal secretion signal and its use for secretion of recombinant proteins.	the secretion signal of the caulobacter crescentus s-layer protein (rsaa) was localized to the c-terminal 82 amino acids of the molecule. protein yield studies showed that 336 or 242 c-terminal residues of rsaa mediated secretion of >50 mg of a cellulase passenger protein per liter to the culture fluids.	2000	10809716
elisa to evaluate plasma anti-asparaginase igg concentrations in patients with acute lymphoblastic leukemia.	the development of antibodies to asparaginase may attenuate the pharmacologic effect of asparaginase treatment, may be associated with hypersensitivity reactions, and may necessitate switching to a different commercial asparaginase preparation for current or future therapy. thus, development of an elisa for measurement of anti-asparaginase antibody levels is important in the clinical setting. an anti-asparaginase antibody reference was established by screening 65 plasma samples from six patients ...	2000	10821949
detection of pseudomonas savastanoi pv. savastanoi in olive plants by enrichment and pcr.	the sequence of the gene iaal of pseudomonas savastanoi ew2009 was used to design primers for pcr amplification. the iaal-derived primers directed the amplification of a 454-bp fragment from genomic dna isolated from 70 strains of p. savastanoi, whereas genomic dna from 93 non-p. savastanoi isolates did not yield this amplified product. a previous bacterial enrichment in the semiselective liquid medium pvf-1 improved the pcr sensitivity level, allowing detection of 10 to 100 cfu/ml of plant extr ...	2000	10831456
thiol-disulfide exchange is involved in the catalytic mechanism of peptide methionine sulfoxide reductase.	peptide methionine sulfoxide reductase (msra; ec ) reverses the inactivation of many proteins due to the oxidation of critical methionine residues by reducing methionine sulfoxide, met(o), to methionine. msra activity is independent of bound metal and cofactors but does require reducing equivalents from either dtt or a thioredoxin-regenerating system. in an effort to understand these observations, the four cysteine residues of bovine msra were mutated to serine in a series of permutations. an an ...	2000	10841552