J Biochem (Tokyo), 1996 Sep, 120(3), 564 - 72 Cloning and expression of an isovaleryl pepstatin-insensitive carboxyl proteinase gene from Xanthomonas sp . T-22; Oda K et al.; Xanthomonas carboxyl proteinase (XCP), isolated from Xanthomonas sp . T-22, is the second example of the unique carboxyl proteinases {EC 3.4.23.33} which are insensitive to the classical aspartic proteinase inhibitor . The gene coding for XCP was cloned, sequenced, and expressed in Escherichia coli . The XCP gene contains an open reading frame of 2,481 base pairs encoding a protein of 827 amino acid residues with a M(r) of 83,677 . The XCP was synthesized as a large precursor consisting of three regions: NH2-terminal prepro (N-Prepro) (237 amino acid residues); mature XCP (398 a.a.residues); and COOH-terminal pro (C-Pro) (192 a.a . residues) . The N-Prepro and mature XCP regions had no sequence similarity to any other proteins reported so far, except the carboxyl proteinase from Pseudomonas sp . 101 {Oda, K., Takahashi, T., Tokuda, Y., Shibano, Y., and Takahashi, S . (1994) J . Biol . Chem . 269, 26518-26524} . The C-Pro region showed high similarity to COOH-terminal regions of other microbial proteinase precursors . E . coli carrying a plasmid containing the cloned wild-type XCP gene produced an 84-kDa protein . This protein was processed into a mature, active form under acidic conditions . This process was completely blocked by tyrostatin, an XCP-specific inhibitor from Kitasatosporia sp . 55, indicating an autocatalytic processing . The purified recombinant XCP had the same characteristics as authentic XCP except for the NH2-terminal amino acid sequence . When the mutant XCP gene truncated in the C-Pro region was expressed in E . coli, an expected 64-kDa protein was detected in the cells, and also processed into the 42-kDa active form under the acidic conditions . Thus, the C-Pro region was not essential for the formation of active mature XCP. Mol Plant Microbe Interact, 1996 Sep, 9(7), 664 - 6 Cloning and characterization of the rpfC gene of Xanthomonas oryzae pv . oryzae: involvement in exopolysaccharide production and virulence to rice; Tang JL et al.; rpfC is one of a cluster of genes which coordinately regulate the synthesis of extracellular enzymes and exopolysaccharide and pathogenicity in Xanthomonas campestris pv . campestris, the black rot pathogen of brassicas . An rpfC homolog which could functionally complement an rpfC mutant of X . campestris pv . campestris was identified in Xanthomonas oryzae pv . oryzae and the gene was characterized . Mutation of this gene in X . oryzae pv . oryzae had no effect on extracellular enzymes, but exopolysaccharide synthesis and virulence to rice were substantially reduced. Mol Plant Microbe Interact, 1996 Sep, 9(7), 584 - 93 A gene for superoxide dismutase from Xanthomonas campestris pv . campestris and its expression during bacterial-plant interactions; Smith SG et al.; A recombinant plasmid selected from a library of Xanthomonas campestris pv . campestris genomic DNA by functional complementation of a superoxide dismutase (SOD)-deficient strain of Escherichia coli contained a gene encoding the major SOD activity of X . campestris pv . campestris . Inhibition and renaturation studies suggested that manganese was the metal cofactor for this SOD . Examination of the nucleotide sequence of an active subclone revealed a 612-bp open reading frame that encodes a protein with high amino acid sequence homology to a range of SOD enzymes . The sod gene was mutagenized with Tn5-lacZ . None of the insertions that abolished SOD-conferring activity were in the correct orientation for lacZ expression . Repeated attempts to introduce these insertions into the chromosome of X . campestris pv . campestris were unsuccessful and it was concluded that the sod gene may be essential for viability . In order to monitor the expression of the sod gene, a sod-gus transcriptional fusion was constructed . Expression of the sod gene varied according to the growth stage of the organism in culture . In planta, the sod gene was induced within 3 to 4 h of inoculation, with similar kinetics during compatible and incompatible interactions with turnip and pepper, respectively. Mol Gen Genet, 1996 Aug 27, 252(1-2), 162 - 8 Two cold-inducible genes encoding lipid transfer protein LTP4 from barley show differential responses to bacterial pathogens; Molina A et al.; The barley genes HvLtp4.2 and HvLtp4.3 both encode the lipid transfer protein LTP4 and are less than 1 kb apart in tail-to-tail orientation . They differ in their non-coding regions from each other and from the gene corresponding to a previously reported Ltp4 cDNA (now Ltp4.1) . Southern blot analysis indicated the existence of three or more Ltp4 genes per haploid genome and showed considerable polymorphism among barley cultivars . We have investigated the transient expression of genes HvLtp4.2 and HvLtp4.3 following transformation by particle bombardment, using promoter fusions to the beta-glucuronidase reporter sequence . In leaves, activities of the two promoters were of the same order as those of the sucrose synthase (Ss1) and cauliflower mosaic virus 35S promoters used as controls . Their expression patterns were similar, except that Ltp4.2 was more active than Ltp4.3 in endosperm, and Ltp4.3 was active in roots, while Ltp4.2 was not . The promoters of both genes were induced by low temperature, both in winter and spring barley cultivars . Northern blot analysis, using the Ltp4-specific probe, indicated that Xanthomonas campestris pv . translucens induced an increase over basal levels of Ltp4 mRNA, while Pseudomonas syringae pv . japonica caused a decrease . The Ltp4.3-Gus promoter fusion also responded in opposite ways to these two compatible bacterial pathogens, whereas the Ltp4.2-Gus construction did not respond to infection. Mol Microbiol, 1996 Aug, 21(3), 449 - 57 Genetic analysis of the transcriptional arrangement of Azotobacter vinelandii alginate biosynthetic genes: identification of two independent promoters; Lloret L et al.; The study of alginate biosynthesis, the exopolysaccharide produced by Azotobacter vinelandii and Pseudomonas aeruginosa, might lead to different biotechnological applications . Here we report the cloning of A . vinelandii algA, the gene coding for the bifunctional enzyme phosphomannose isomerase-guanosine diphospho-o-mannose pyrophosphorylase (PMI-GMP) . This gene was selected by the complementation for xanthan gum production of Xanthomonas campestris pv . campestris xanB-mutants, which lack this enzymatic activity . The complementing cosmid clones selected, besides containing algA, presented a gene coding for an alginate lyase activity (algL), and some of them also contained algD which codes for GDP-mannose dehydrogenase . We present here the characterization of the A . vinelandii chromosomal region comprising algD and its promoter region, algA and algL, showing that, as previously reported for P . aeruginosa, A . vinelandii has a cluster of the biosynthetic alginate genes . We provide evidence for the presence of an algD-independent promoter in this region which transcribes at least algL and algA, and which is regulated in a manner that differs from that of the algD promoter. J Bacteriol, 1996 Aug, 178(16), 4814 - 21 Isolation and nucleotide sequence of the GDP-mannose:cellobiosyl-diphosphopolyprenol alpha-mannosyltransferase gene from Acetobacter xylinum; Petroni EA et al.; A genetic locus from Acetobacter xylinum involved in acetan polysaccharide synthesis has been characterized . The chromosomal region was identified by screening a genomic library of A . xylinum in a Xanthomonas campestris mutant defective in xanthan polysaccharide synthesis . The A . xylinum cosmid clone can functionally complement a xanthan-negative mutant . The polymer produced by the recombinant strain was found to be indistinguishable from xanthan . Insertion mutagenesis and subcloning of the cosmid clone combined with complementation studies allowed the identification of a 2.3-kb fragment of A . xylinum chromosomal DNA . The nucleotide sequence of this fragment was analyzed and found to contain an open reading frame (aceA) of 1,182 bp encoding a protein of 43.2 kDa . Results from biochemical and genetic analyses strongly suggest that the aceA gene encodes the GDP-mannose:cellobiosyl-diphosphopolyprenol alpha-mannosyltransferase enzyme, which is responsible for the transfer of an alpha-mannosyl residue from GDP-Man to cellobiosyl-diphosphopolyprenol . A search for similarities with other known mannosyltransferases revealed that all bacterial alpha-mannosyltransferases have a short COOH-terminal amino acid sequence in common. J Bacteriol, 1996 Aug, 178(15), 4590 - 6 At least two separate gene clusters are involved in albicidin production by Xanthomonas albilineans; Rott PC et al.; Transposon mutagenesis was used to obtain mutations affecting production of the toxin albicidin in Xanthomonas albilineans, which causes leaf scald disease of sugarcane and is also pathogenic to corn . Transposon Tn5-gusA inserted randomly into genomic DNA of X . albilineans Xa23R1 at a frequency of 10(-4) to 10(-5) per recipient after conjugal transfer from Escherichia coli . Fifty prototrophic mutants defective in albicidin production were isolated from 7,100 Tn5-gusA insertional derivatives tested for toxin production by an antibiosis bioassay . EcoRI fragments containing Tn5 flanking sequences from two mutants (AM15 and AM40) were cloned and used to probe a wild-type Xa23R1 DNA library by colony hybridization . Nine cosmids showed homology to the AM15 probe, and six showed homology to the AM40 probe . Four cosmid clones hybridized to both probes . Forty-five of the 50 defective mutants were restored to albicidin production with two overlapping cosmid clones . Restriction mapping showed that these mutants span a genomic region of about 48 kb . At least one other gene cluster is also involved in albicidin production in Xa23R1 . DNA fragments from the 48-kb cluster proved to be very specific to X . albilineans . Some mutants affected in albicidin production retain their ability to colonize sugarcane cultivated in vitro. Eur J Clin Microbiol Infect Dis, 1996 Jul, 15(7), 607 - 10 A new selective differential medium for isolation of Stenotrophomonas maltophilia; Kerr KG et al.; A new selective differential medium for the isolation of Stenotrophomonas (formerly Xanthomonas) maltophilia was developed . The medium, VIA agar, contained vancomycin, imipenem, and amphotericin B as selective agents and incorporated a mannitol/bromothymol blue indicator system . Compared with Xanthomonas maltophilia Selective Medium (XMSM), VIA agar was less inhibitory to Stenotrophomonas maltophilia and was more selective than XMSM in preventing the growth of unwanted bacteria from contaminated specimens . Although vancomycin-resistant strains of Enterococcus faecium may grow on VIA agar, these can be easily distinguished from Stenotrophomonas maltophilia because of mannitol fermentation. J Bacteriol, 1996 Jul, 178(14), 4313 - 8 Promoter analysis of the Xanthomonas campestris pv . campestris gum operon directing biosynthesis of the xanthan polysaccharide; Katzen F et al.; The Xanthomonas campestris gum gene cluster is composed of 12 genes designated gumB, -C, -D, -E, -F, -G, -H, -I, -J, -K, -L, and -M . The transcriptional organization of this gene cluster was analyzed by the construction of gum-lacZ transcriptional fusions in association with plasmid integration mutagenesis . This analysis, coupled with primer extension assays, indicated that the gum region was mainly expressed as an operon from a promoter located upstream of the first gene, gumB. Microbiology, 1996 Jun, 142 ( Pt 6), 1505 - 12 Expression of periplasmic alpha-amylase of Xanthomonas campestris K-11151 in Escherichia coli and its action on maltose; Abe J et al.; A gene encoding the periplasmic alpha-amylase of Xanthomonas campestris K-11151 was cloned into Escherichia coli using pUC19 as a vector . An ORF of 1578 bp was deduced to be the amylase structural gene . The primary structure of the enzyme had little identity with other alpha-amylases, except with the enzyme from Bacillus megaterium . The enzyme was expressed in E . coli from the lac promoter of pUC19 and was found to be transported to the periplasmic space . The expressed enzyme showed the same thermal stability, optimum temperature and substrate specificity as the enzyme from X . campestris . The enzyme formed maltotetraose, but not 6(1)- nor 6(2)-maltosyl-maltose, from maltose by the reverse reaction, and the tetraose was then hydrolysed to maltotriose and glucose . The addition of maltotriose enhanced the production of glucose from maltose . In addition, maltose was formed by the condensation of glucose by the enzyme . Thus, the periplasmic alpha-amylase of X . campestris was shown to produce glucose from maltose by hydrolysing maltotetraose and possibly higher maltooligosaccharides, which were the products of a condensation reaction, as a major pathway, and by direct hydrolysis of maltose as a minor pathway. J Bacteriol, 1996 Jun, 178(12), 3578 - 84 Heterologous growth phase- and temperature-dependent expression and H2O2 toxicity protection of a superoxide-inducible monofunctional catalase gene from Xanthomonas oryzae pv . oryzae; Mongkolsuk S et al.; Catalase is an important protective enzyme against H2O2 toxicity . Here, we report the characterization of a Xanthomonas oryzae pv . oryzae catalase gene (katX) . The gene was localized and its nucleotide sequence was determined . The gene codes for a 77-kDa polypeptide . The deduced katX amino acid sequence shares regions of high identity with other monofunctional catalases in a range of organisms from bacteria to eukaryotes . The transcriptional regulation of katX was atypical of bacterial monofunctional kat genes . Northern (RNA) analysis showed that katX transcription was highly induced by treatments with low concentrations of menadione, a superoxide generator, and methyl methanesulfonate, a mutagen . It was only weakly induced by H2O2 . Unlike in other bacteria, a high level of catalase in Xanthomonas spp . provided protection from the growth-inhibitory and killing effects of H2O2 but not from those of organic peroxides and superoxide generators . Unexpectedly, heterologous expression of katX in Escherichia coli was both growth phase and temperature dependent . Catalase activity in E . coli kat mutants harboring katX on an expression vector was detectable only when the cells entered the stationary phase of growth and at 28 degrees C . The patterns of transcription regulation, heterologous expression, and physiological function of katX are different from previously studied bacterial kat genes. Am Surg, 1996 Jun, 62(6), 478 - 80 Characteristics of Xanthomonas infections in critically ill surgical patients; Cornwell EE 3rd et al.; The aim of our study was to describe the characteristics of Xanthomonas infections in a population of critically ill surgical patients . The clinical records and microbiological data on 93 patients in a surgical intensive care unit (SICU) developing Xanthomonas infections were reviewed . Xanthomonas was isolated in 125 sites in the 93 patients . Their average age was 48 years (range, 14-94) . Mortality occurred in 25 patients (26.9%) versus 10.3 per cent of SICU patients in general (P < 0.05) . Patients were in the SICU for an average of 11.9 days before developing a positive Xanthomonas culture, and 87 per cent (81/93) of patients developed an infection at some other site before isolation of Xanthomonas . Trimethoprim sulfamethoxazole was the only drug to which the isolates were commonly sensitive (123/125 = 98.4%) . We conclude that Xanthomonas 1) is associated with increased mortality; 2) is resistant to many of the drugs that usually cover Gram-negative infections; and 3) commonly complicates a prolonged intensive care stay, thus serving as a marker for severity of illness. Mikrobiologiia, 1996 May-Jun, 65(3), 326 - 32 {Lytic action of lysoamidase from Xanthomonas sp . correlates with the presence of the target ribitol teichoic acids in the cell wall of gram-positive bacteria}; Kulaev IS et al.; Lysoamidase, a bacteriolytic complex from the culture liquid of Xanthomonas sp., hydrolyzed the cells walls of Staphylococcus aureus, Streptomyces chrysomallus, and Streptomyces azureus, which contain ribitol teichoic acids in addition to peptidoglycan . The cell walls of Streptomyces roseoflavus, Glycomyces harhinensis, and Nocardiopsis dassonvillei, containing glycerol teichoic acids, were not hydrolyzed by lysoamidase . The extent of the hydrolysis of 20-h Str . chrysomallus cells and cell walls, containing 40% ribitol teichoic acids, was considerably higher than that of 40-h cells and cell walls, containing 15% teichoic acids . Homogeneous bacteriolytic enzymes of the lysoamidase complex (muramidase and two bacteriolytic peptidases) most efficiently hydrolyzed S . aureus and Str . chrysomallus cell walls, characterized by the highest content of ribitol teichoic acids, and did not hydrolyze purified peptidoglycan. Graefes Arch Clin Exp Ophthalmol, 1996 May, 234(5), 311 - 4 The effect of concurrent Pseudomonas or Xanthomonas exposure on adherence of Acanthamoeba castellanii to soft contact lenses; Kelly LD et al.; BACKGROUND: Approximately 85% of Acanthamoeba-contaminated contact lens systems in asymptomatic patients have concurrent bacterial contamination . Pseudomonas aeruginosa and Xanthomonas maltophilia are common contact lens contaminants; we investigated the effect of coincubation of Acanthamoeba adherence to contact lenses . METHODS: A . castellanii, 1 x 10(5) organisms/ml, was coincubated with P . aeruginosa or X . maltophilia, 1 x 10(8) CFU/ml in phosphate-buffered saline . Sterile, unworn polymacon, etafilcon A or lidofilcon contact lens were investigated . The experimental groups were: (I) lenses exposed to bacteria for 1 h, then Acanthamoeba for 2 h; (II) lenses exposed concurrently to bacteria and Acanthamoeba for 2 h; (III) Acanthamoeba coincubated with bacteria for 24 h, then lenses exposed for 2 h; (IV) lenses exposed to Acanthamoeba for 2 h (control) . RESULTS: For all experimental groups, Acanthamoeba adherence was greater to lidofilcon than to polymacon and etafilcon . For both P . aeruginosa and X . maltophilia, neither group I nor group II displayed greater Acanthamoeba adherence than group IV . Group III exhibited significantly less adherence than group IV for lidofilcon and polymacon . The decrease in group III adherence reflected an overall decrease in Acanthamoeba trophozoite concentration . CONCLUSION: Short bacteria/Acanthamoeba coincubation times did not result in increased Acanthamoeba adherence . Twenty-four-hour coincubation resulted in decreased adherence for Pseudomonas and unchanged adherence rates for Xanthomonas . This model suggests that Pseudomonas or Xanthomonas co-contamination does not necessarily facilitate quantitative Acanthamoeba contact lens adherence. Biochem Biophys Res Commun, 1996 Apr 16, 221(2), 459 - 65 Isolation and characterization of the recA gene of Xanthomonas campestris pv . campestris; Lee TC et al.; A 1.8-kb NsiI-StuI fragment containing the recA gene of Xanthomonas campestris pv . campestris was cloned by a PCR-based approach and complementation of Escherichia coli HB 101 . Sequence analysis of this fragment revealed an ORF (orf343) of 1,032 bp able to encode a protein of 343 amino acids with a calculated MW of 37,021 Da, a size similar to the values detected by in vitro system and Western blotting . It showed 69.6% identity to the E . coli RecA in amino acid sequence . Amino acid residues of the E coli RecA associated with functional activities are conserved in this Xc17 RecA . The recA mutant, L1, constructed by gene replacement, was sensitive to ultraviolet irradiation and methyl methanesulfonate, and deficient in homologous recombination. J Antimicrob Chemother, 1996 Apr, 37(4), 665 - 76 Temperature-dependent aminoglycoside resistance in Stenotrophomonas (Xanthomonas) maltophilia; alterations in protein and lipopolysaccharide with growth temperature; Rahmati-Bahram A et al.; Clinical strains of Stenotrophomonas (Xanthomonas) maltophilia often show large, growth temperature-dependent, variations in their susceptibility (TDVS) to aminoglycoside antibiotics . Strains showing more than a fourfold increase in susceptibility between 30 degrees and 37 degrees C (TDVS+ strains; n = 23) were contrasted with those showing lesser variation (TDVS- strains; n = 15) in studies of growth temperature-dependent variation in protein and cell-wall lipopolysaccharide (LPS) electrophoresis patterns in an attempt to determine the mechanism of TDVS . Several proteins showed increased intensity with increasing growth temperature . These comprised bands at c . 65, 55, 42.5, 26 and 21.5 kDa in the whole cell proteins, an outer membrane protein band at c . 21.5 kDa, and cytoplasmic membrane protein bands at c . 42.5 and 27 kDa . Two whole cell protein bands at c . 30 and 24 kDa and three outer membrane protein bands at c . 45, 30 and 24 kDa decreased in intensity with increasing growth temperature . However, there was no correlation with the extent of variation in susceptibility, either in the extent of temperature dependent changes in protein banding patterns, or the presence or absence of specific protein bands . By contrast, temperature-dependent variation in LPS patterns correlated well with TDVS . TDVS+ strains yielded intense ladder patterns of more than 30 discrete bands, and the mean molecular weight of the ladder pattern was markedly higher at growth temperatures < or = 30 degrees C, than at > or = 37 degrees C . TDVS- strains gave a clearly distinct high mol . wt LPS banding pattern showing fewer, less intense bands and a smaller and less consistent shift in mean molecular weight with temperature . Strains which were clearly resistant at 30 degrees and 37 degrees C, had a high mol . wt . polysaccharide component but an absence of the typical LPS-ladder pattern . We conclude that the temperature-dependent variation in the aminoglycoside susceptibility of this species was not correlated with any detectable change in protein composition, but correlated well with changes in LPS structure. FEMS Microbiol Lett, 1996 Mar 15, 137(1), 115 - 21 Identification, cloning and sequencing the aceA gene involved in acetan biosynthesis in Acetobacter xylinum; Griffin AM et al.; The aceA gene from Acetobacter xylinum was identified and cloned from a genomic DNA library . The complete DNA sequence was determined and computer analysis of the translated gene sequence revealed homology with the deduced amino acid sequence of gumD from Xanthomonas campestris . Therefore aceA is likely to encode the phosphate-prenyl glucose l-phosphate transferase catalyzing the first step in acetan biosynthesis in A . xylinum. Clin Infect Dis, 1996 Mar, 22(3), 508 - 12 Bacteremia due to Stenotrophomonas (Xanthomonas) maltophilia: a prospective, multicenter study of 91 episodes; Muder RR et al.; We identified 91 cases of bacteremia due to Stenotrophomonas (Xanthomonas) maltophilia in a prospective, multicenter observational study . The patients were highly compromised; the majority had an underlying malignancy, had received immunosuppressive therapy, and had indwelling venous catheters . Although 94% of patients received an antimicrobial agent to which the blood isolate was susceptible, the mortality among these patients 14 days after the onset of bacteremia was 21% . Mortality was significantly correlated with the presence of a hematologic malignancy or neutropenia or transplantation, immunosuppressive therapy, and a severity-of-illness score of > 4 . S . maltophilia infection is associated with substantial morbidity and mortality among highly compromised patients . The organism is typically resistant to expanded spectrum beta-lactam agents and aminoglycoside antibiotics . Trimethoprim-sulfamethoxazole should be administered if the isolate is susceptible to this combination; addition of another agent to which the isolate is susceptible should be considered in treating patients who are neutropenic, immunocompromised, or critically ill. Carbohydr Res, 1996 Feb 28, 282(1), 149 - 56 Structure of the O3 antigen of Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia; Winn AM et al.; The O antigen isolated from the lipopolysaccharide of a strain of Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia serogroup O3 was found to contain 4-acetamido-4,6-dideoxy-D-galactose, D-fucose, and N-acetyl-D-glucosamine . By means of chemical degradations and NMR spectroscopy the repeating unit of the O-specific polymer was determined to be a branched trisaccharide repeating-unit of the structure shown. J Biol Chem, 1996 Feb 2, 271(5), 2703 - 8 XpsD, an outer membrane protein required for protein secretion by Xanthomonas campestris pv . campestris, forms a multimer; Chen LY et al.; XpsD is an outer membrane lipoprotein, required for the secretion of extracellular enzymes by Xanthomonas campestris pv . campestris . Our previous studies indicated that when the xpsD gene was interrupted by transposon Tn5, extracellular enzymes were accumulated in the periplasm (Hu, N.-T., Hung, M.-N., Chiou, S.-J., Tang, F., Chiang, D.-C . Huang, H.-Y . and Wu, C.-Y . (1992) J . Bacteriol . 174, 2679-2687) . In this study, we constructed a series of substitutions and deletion mutant xpsD genes to investigate the roles of NH2- and COOH-terminal halves of XpsD in protein secretory function . Among these secretion defective xpsD mutations, one group (encoded by pCD105, pYLA, pKdA6, and pKD2) caused secretion interference when co-expressed with wild type xpsD, but the other (encoded by pMH7, pKdPs, and pKDT) did not . Cross-linking studies and gel filtration chromatography analysis indicated that the wild type XpsD protein forms a multimer in its native state . Similar gel filtration analysis of xpsD mutants revealed positive correlations between multimer formation and secretion interfering properties exerted by the mutant XpsD proteins in the parental strain XC1701 . Those mutant XpsD proteins (encoded by pCD105, pYL4, pKdA6, and pKD2) that caused secretion interference formed multimers that are similar to the wild type XpsD multimers and those (encoded by pMH7, pKdPs, and pKDT) that did not formed smaller ones . Furthermore, gel filtration and anion exchange chromatography analyses indicated that the wild type XpsD protein co-fractionated with XpsD (delta 29-428) or XpsD (delta 448-650) protein but not with XpsD (delta 74-303) or XpsD (delta 553-759) protein . We propose that the mutant XpsD (delta 29-428) protein caused secretion interference primarily by forming mixed nonfunctional multimers with the wild type XpsD protein in XC1701 (pCD105), whereas the mutant XpsD (delta 74-303) did so by competing for unknown factor(s) in XC1701(pYL4). APMIS, 1996 Feb, 104(2), 108 - 14 In vitro susceptibility of 124 Xanthomonas maltophilia (Stenotrophomonas maltophilia) isolates: comparison of the agar dilution method with the E-test and two agar diffusion methods; Arpi M et al.; The in vitro susceptibility of 124 Xanthomonas maltophilia isolates was tested by four methods: Agar dilution (reference method), E-test, a disk diffusion and a tablet diffusion method . Trimethoprim-sulfamethoxazole had the highest activity against X . maltophilia, followed by a combination of aztreonam-clavulanic acid at different ratios, the ratio 1:1 being the most active with a susceptibility rate of 85% as compared to 2% for aztreonam alone . Addition of the beta-lactamase inhibitor tazobactam to piperacillin enhanced the rate of susceptible isolates from 31% to 53%, Relatively few isolates were susceptible to ciprofloxacin (27%) and gentamicin (9%) . Generally, the disk diffusion method had a considerably higher frequency of "very major" discrepancies when compared with the agar dilution method than with the other methods . The susceptibility of X . maltophilia to trimethoprim-sulfamethoxazole and ciprofloxacin could reliably be determined by all the diffusion methods tested, but otherwise the agar dilution method is to be preferred . A standardized and reliable diffusion method for susceptibility testing of X . maltophilia remains to be found . Trimethoprim-sulfamethoxazole must be considered the drug of choice in the treatment of severe X . maltophilia infections . The combination aztreonam-clavulanic acid is promising, but must be proved in a clinical setting. J Bacteriol, 1996 Feb, 178(4), 1061 - 9 Expression and localization of HrpA1, a protein of Xanthomonas campestris pv . vesicatoria essential for pathogenicity and induction ofthe hypersensitive reaction; Wengelnik K et al.; The hrp cluster of the pepper and tomato pathogen Xanthomonas campestris pv . vesicatoria is required for both pathogenicity on susceptible host plants and induction of the hypersensitive reaction on resistant plants . The hrpA locus is located at the left end of the 25-kb hrp region and encodes a single 64-kDa Hrp protein, HrpA1, which belongs to the PulD superfamily of proteins involved in type II and type III protein secretion . In this study, we developed a defined medium without any plant-derived molecules that induces expression of hrpA in vitro . The hrpA transcription start site was mapped in the coding region of the hrpB8 gene, which is the last gene of the hrpB operon . The inducible hrpA promoter shows no homology to known promoter elements or other hrp loci of X . campestris pv . vesicatoria . hrpA expression was shown to be independent of the hrp regulatory gene hrpX . The amino acid sequence of the HrpA1 protein is predicted to contain an N-terminal signal sequence and no further transmembrane domains and to be rich in beta-sheet stretches . Expression of HrpA1 in Escherichia coli cells causes induction of the psp operon like some of its counterparts, suggesting some commonality of function and that HrpA1 forms multimers . The protein product of hrpA1 was identified by using a specific polyclonal antibody . Cell fractionation studies demonstrated that the HrpA1 protein is localized in the outer membrane of X . campestris pv . vesicatoria . HrpA1 is the first component of the Hrp secretion system whose localization has been determined in the original organism. Biochem Biophys Res Commun, 1996 Jan 5, 218(1), 12 - 6 A region of the filamentous phage phi Lf genome that can support autonomous replication and miniphage production; Lin NT et al.; A 2028-bp fragment from the RF DNA of phi Lf, a filamentous phage of Xanthomonas campestris pv . campestris, was maintained autonomously as a minireplicon . Upon superinfection of the cells harboring the minireplicon with phi Lf, transducing miniphage particles were released . The minireplicon contained an open reading frame (ORF346) able to encode a polypeptide of MW39144, which possessed consensus motifs found in the Rep proteins from various sources . These findings suggested ORF346 to be the gene encoding replication initiation protein, gene II (gII) of phi Lf . Upstream to ORF346 were sequences with potential to form hairpin structures and a sequence similar to the integration host factor (IHF) binding site, structures similar to the intergenic region (IR) of the Ff phages . A 15 bp AT-rich core for phi Lf integration was found 37 bp downstream to the IHF binding site. J Hosp Infect, 1996 Jan, 32(1), 39 - 50 Use of random amplified polymorphic DNA for epidemiological typing of Stenotrophomonas maltophilia; Davin-Regli A et al.; We used the technique of random amplification of polymorphic DNA (RAPD) to type 130 isolates of Stenotrophomonas (Xanthomonas) maltophilia, using four arbitrary short primers . Of the 130 isolates, 51 were from the hospital environment, 48 from clinical specimens and 31 were geographically diverse environmental isolates . DNA amplification with the four sets of primers generated 112 RAPD patterns that differed by two or more bands in one of the four primers . Sixteen pairs of isolates were of the same RAPD pattern and some of these pairs represented clinical strains obtained from patients hospitalized at the same time in the same ward . In three patients, two to three strains of S . maltophilia which gave different RAPD fingerprints were isolated on the same day from different specimens . RAPD fingerprinting demonstrated great genomic diversity within the species S . maltophilia and provided an effective method for the study of the epidemiology of both clinical and environmental strains. Indian J Exp Biol, 1996 Jan, 34(1), 27 - 31 Cloning of extracellular lipase gene from Xanthomonas campestris pathovar sesami on to Escherichia coli; Sheela P et al.; A lipase gene from X . campestris pv . sesami (strain XcS 1) causal agent of leaf spot disease of Sesamum indicum, was cloned onto E . colt . XcS showed the presence of lip+ transformants on Dye's medium with 1% glycerol as sole carbon source . The recombinant plasmids were isolated and when digested with Eco R1, yielded 2 fragments with molecular weights 4.0 and 4.8 kb . Thus a 8.8 kb insert DNA fragment was obtained which showed lipase activity. Yi Chuan Xue Bao, 1996, 23(2), 110 - 6 {A PCR marker-based selection for resistance to bacterial blight in rice}; Lu C et al.; Molecular marker-based selection in plant breeding requires not only suitable molecular markers closely linked to the known genes, but a simple, economic and reliable analyzing technique . We report here a useful PCR marker for genetic diagnostics in breeding for resistance to rice bacterial blight . Xa21 is a newly found gene of rice which confers resistance to bacterial blight caused by Xanthomonas oryzae pv . oryzae . We produced two F2 populations between one resistant line IRBB21 containing Xa21 and two susceptible varieties, respectively . One PCR marker, PB78, detected polymorphism between the susceptible varieties and the resistant line . Cosegregation between Xa21 and PB78 was studied in the two F2 populations . The results showed that Xa21 was closely linked to the molecular marker, the crossing over value was 2.48% . Marker-based selection revealed that 100% of the plants with homozygous resistant genotype of PB78 showed resistance to bacterial blight . The available approaches detecting molecular markers in plant breeding are also discussed. Carbohydr Res, 1995 Dec 20, 278(2), 205 - 25 A conformational model for cyclic beta-(1-->2)-linked glucans based on NMR analysis of the beta-glucans produced by Xanthomonas campestris; York WS; A cyclic hexadecaglucoside containing 15 beta-(1-->2)-linkages and one alpha-(1-->6)-linkage (A . Amemura and J . Cabrera-Crespo, J . Gen . Microbiol . 132 (1986) 2443-2452) was purified from cultures of Xanthomonas campestris . The homogeneity of this glucan preparation facilitated the complete assignment of its 1H NMR spectrum and the assignment of all of the C-1 and C-2 resonances in its 13C NMR spectrum to specific residues within the glucan . The resonances (i.e., H-1, H-2, C-1 and C-2) that are closely associated with the beta-(1-->2) glucosidic bonds of this glucan are dispersed over a relatively broad chemical shift range . This chemical shift dispersion is attributed to the differences in the time-averaged geometry of individual beta-(1-->2)-linked glycosidic bonds in this glucan and is consistent with the hypothesis that these glycosidic bonds have less conformational freedom than do the glycosidic bonds in a linear beta-(1-->2)-linked glucan . The chemical shifts of H-1, H-2, C-1, and C-2 exhibit an alternating pattern when plotted as a function of their locations within the macrocyclic ring, suggesting that the glycosidic bond geometry also alternates in the glucan . A new conformational model for cyclic beta-(1-->2)-linked glucans was developed on the basis of these observations . This model is consistent with the observed spectroscopic features of all cyclic beta-(1-->2)-linked glucans known to be produced by Gram-negative bacteria. FEMS Microbiol Lett, 1995 Dec 15, 134(2-3), 189 - 94 Rapid inhibition of protein histidine phosphorylation by UV-irradiation in Xanthomonas oryzae pv . oryzae; Huang HJ et al.; Exposure of Xanthomonas oryzae pv . oryzae cells to 254 nm UV radiation resulted in an alteration of protein phosphorylation . Labelling of the phosphohistidine-containing proteins with molecular masses of 81 and 32 kDa, named p81 and p32, was rapidly reduced following UV irradiation in the early exponential cells, but the decrease was not detected in mid-exponential cells . Mitomycin C, a DNA replication inhibitor, and rifampicin, a drug generally used to inhibit RNA synthesis and DNA replication, were also found to reduce the histidyl phosphorylation . However, this alteration of protein phosphorylation was not hindered by chloramphenicol treatment . A possible role for these histidyl phosphoproteins in sensing UV light is proposed. Science, 1995 Dec 15, 270(5243), 1804 - 6 A receptor kinase-like protein encoded by the rice disease resistance gene, Xa21; Song WY et al.; The rice Xa21 gene, which confers resistance to Xanthomonas oryzae pv . oryzae race 6, was isolated by positional cloning . Fifty transgenic rice plants carrying the cloned Xa21 gene display high levels of resistance to the pathogen . The sequence of the predicted protein, which carries both a leucine-rich repeat motif and a serine-threonine kinase-like domain, suggests a role in cell surface recognition of a pathogen ligand and subsequent activation of an intracellular defense response . Characterization of Xa21 should facilitate understanding of plant disease resistance and lead to engineered resistance in rice. Microbiologia, 1995 Dec, 11(4), 471 - 84 {Kinetic model of micro-organism growth: the case of Xanthomonas campestris}; Garcia-Ochoa F et al.; Microbial growth is studied and kinetic models to describe the process rate useful in the scale-up are proposed . The growth of Xanthomonas campestris NRRL B-1459, a bacterium producing xanthan, a major industrial gum, is studied . Experimental data are arranged by means of different methods, and linear and non-linear regression techniques are applied in several ways (i.e . fixing or not fixing the values of certain parameters) and they are compared . To obtain parameter values with statistical meaning, two parameters must be calculated (namely, the maximum specific growth rate and the maximum biomass concentration available) by means of a non-linear regression technique employing the logistic equation . The maximum specific growth rate is related to temperature by means of different equations, but that of Ratkowsky et al . is the most suitable for X . campestris growth . Studied variables present no tendency to error and the reproduction of experimental data is very good. Microbiology, 1995 Dec, 141 ( Pt 12), 3229 - 39 tRNA intergenic spacers reveal polymorphisms diagnostic for Xanthomonas albilineans; Honeycutt RJ et al.; A PCR-based detection system was developed for Xanthomonas albilineans, a pathogen of sugarcane, and other related xanthomonads, using the conserved sequence of two adjacent tRNA genes and the variable length and sequence of the spacer region between them . An appropriate region was identified as follows: tRNA genes with the same anticodon from a wide variety of bacteria were aligned and the most frequent base at each position was chosen to derive primers that would anneal to the gene in either orientation . Pairs of such primers were screened against various Xanthomonas species and members of related genera using PCR at low to moderate annealing stringency . A subset of these pairs of tRNA consensus primers gave one or more PCR products which generally displayed interspecific length variability . The primer pair 5'-3' tRNA(ala) and 3'-5' tRNA(ile) showed interspecific length polymorphisms between X . albilineans and all other Xanthomonas species examined . These PCR products were cloned and sequenced from four isolates of X . albilineans and four isolates from different pathovars of X . campestris, and the spacer length variation confirmed . Specific tRNA gene primers were derived from the tRNA gene sequences . These primers yielded a PCR product of a characteristic length within most Xanthomonas species and pathovars tested . When a primer that projected from tRNA(ala) into the 3' end of the variable intergenic spacer was used with a tRNA(ile)-specific primer, PCR was a very sensitive diagnostic test for X . albilineans-infected sugarcane and gave no product or only a faint product with other species of bacteria . The specificity of this PCR-based detection system was further enhanced by a nested PCR reaction that took advantage of the fact that the tRNA(ala)-tRNA(ile) region was found to be embedded in a 16S rRNA-23S rRNA gene spacer . By amplifying the region between the 16S rRNA gene and tRNA(ile) or between the tRNA(ala) and the 23S rRNA gene, the subsequent nested PCR product was shown to be X . albilineans-specific. Mol Microbiol, 1995 Nov, 18(4), 769 - 77 The type IV pre-pilin leader peptidase of Xanthomonas campestris pv . campestris is functional without conserved cysteine residues; Hu NT et al.; Type IV pre-pilin leader peptidase was demonstrated to be required for protein secretion, in addition to its involvement in biogenesis of type IV pIII . The type IV pre-pilin leader peptidase gene of Xanthomonas campestris pv . campestris was located on a 3 kb Accl fragment on account of its hybridization with the DNA fragment containing the type IV pre-pilin leader-peptidase gene pilD/xcpA of Pseudomonas aeruginosa . Sequencing of the cloned fragment revealed an open reading frame (ORF) (designated xpsO) of 287 amino acid residues . A protein with an apparent molecular mass of approximately 32.5 kDa was synthesized in vitro from a DNA fragment containing the xpsO gene . The amino acid sequence shares 50% identity with that of PilD throughout the entire sequence . Among other type IV pre-pilin leader peptidases, XpsO is unique in not having the two conserved -CXXC-motifs in a cytoplasmic domain . Instead, new motifs were noted when the protein was compared with XpsE, which is another member of the extracellular protein-secretion machinery . When the xpsO gene was introduced into the pilD mutant of P . aeruginosa, both the sensitivity against infection with the pilus-specific phage PO4 and the ability to secrete extracellular protein were recovered . Furthermore, immunoblot analysis indicated that the P . aeruginosa pilin was apparently processed in vivo by the xpsO gene product. Biosci Biotechnol Biochem, 1995 Nov, 59(11), 2087 - 90 Prolidase from Xanthomonas maltophilia: purification and characterization of the enzyme; Suga K et al.; Prolidase (iminodipeptidase, EC 3.4.13.9) was purified from an extract of Xanthomonas maltophilia, by ammonium sulfate fractionation and sequential chromatographies on DEAE-Toyopearl, Toyopearl HW65C, FPLC-Hiload Superdex 200 pg, and FPLC-Hitrap Q columns, which an activity recovery of 2.3% . The enzyme was the most active at pH 7.5 with Leu-Pro as substrate . It was stable between pH 6.0 and 8.5 for 60 min at 37 degrees C and retained half of activity after 60 min at 37 degrees C . The isoelectric point of the enzyme was 3.7 . Its molecular weight was estimated to be 100,000 by gel filtration on FPLC-Hiload Superdex 200 and 51,000 by SDS-PAGE, suggesting that it is a dimer . It hydrolyzed dipeptides only if proline is located at the carboxyl terminal position . The enzyme was inhibited by PCMB and o-phenanthroline, and was activated by Mn2+. Genetics, 1995 Oct, 141(2), 675 - 82 Genomic localization of tomato genes that control a hypersensitive reaction to Xanthomonas campestris pv . vesicatoria (Doidge) dye; Yu ZH et al.; Xanthomonas campestris pv . vesicatoria causes bacterial spot, one of the most serious diseases of tomatoes . The lycopersicon esculentum accession 'Hawaii 7998' is the only reliable source of resistance to race 1 strains of the pathogen . This resistance is associated with a hypersensitive reaction controlled by multiple nondominant genes . The inoculated area becomes fully necrotic 24 hr after inoculation in 'Hawaii 7998,' whereas full necrosis is observed 5 and 4 days after inoculation in the susceptible species L . pennellii (LA 716) and their F1, respectively . An interspecific backcross population, using 'Hawaii 7998' as the recurrent parent, was analyzed to determine the linkage relationships between the resistance genes and 135 molecular marker loci . The range of responses of the BC1 population included those of the parents . Linkage to a hypersensitive response factor was assessed by comparing the rates of necrosis development between homozygous and heterozygous plants at 8 hr-intervals . Three factors that affect the hypersensitive response of 'Hawaii 7998' were detected . One factor is on the short arm of chromosome I, another on the long arm of chromosome I, and a third on the long arm of chromosome 5 . These factors appeared to act independently and to have additive effects. Antimicrob Agents Chemother, 1995 Oct, 39(10), 2220 - 3 In vitro activities of antimicrobial combinations against Stenotrophomonas (Xanthomonas) maltophilia; Poulos CD et al.; Stenotrophomonas (Xanthomonas) maltophilia is inherently resistant to multiple antimicrobial agents . In order to investigate the in vitro potential of combinations of antimicrobial agents, we obtained 230 epidemiologically unrelated clinical isolates from seven hospitals across Canada and from Northwestern Memorial Hospital in Chicago . Ticarcillin-clavulanate combined with ciprofloxacin or trimethoprim-sulfamethoxazole were assayed for synergy against 31 ticarcillin-resistant strains of S . maltophilia by using microtiter checkerboard panels and against 20 strains by using time-kill methodology . The combination of ciprofloxacin with ceftazidime was also evaluated by time-kill studies . Ticarcillin-clavulanate plus trimethoprim-sulfamethoxazole demonstrated synergy by checkerboard panels, with fractional inhibitory concentration indices ranging from 0.033 to 0.49, and by time-kill studies for all 20 strains tested . Synergy between ticarcillin-clavulanate plus ciprofloxacin was found by the checkerboard method for 24 of 31 strains (77%), with fractional inhibitory concentration indices ranging from 0.188 to 0.75 . A correlation between synergy by the checkerboard method and the reference time-kill study method was not observed for ticarcillin-clavulanate plus ciprofloxacin, with results for 3 of 10 strains being nonconcordant . Synergy with both ticarcillin-clavulanate plus ciprofloxacin and ceftazidime plus ciprofloxacin by the time-kill method was found to correlate with ciprofloxacin MICs of <32 micrograms/ml and zone diameters of >15 mm on Mueller-Hinton agar . Evaluation of these combinations in vivo may be warranted. J Antibiot (Tokyo), 1995 Oct, 48(10), 1081 - 5 Isolation and structure determination of two novel phenazines from a Streptomyces with inhibitory activity against metallo-enzymes, including metallo-beta-lactamase; Gilpin ML et al.; Two novel metabolites, SB 212021 and SB 212305, have been isolated from a Streptomyces and shown to have molecular formulae of C15H10N2O5 and C20H17N3O8S, respectively . The structures were deduced by a combination of NMR techniques and mass spectral fragmentation patterns and shown to be novel members of the phenazine group of antibiotics . In the absence of added zinc, both compounds had IC50's of 1-75 microM for the Bacteroides fragilis 262 CfiA and Xanthomonas maltophilia L-1 metallo-beta-lactamases . The compounds also inhibited ACE with IC50's of 55 and 68 microM, respectively . Mode of action studies illustrate that the compounds inhibit some metalloenzymes by chelation of the active site metal ion . They exhibit poor antibacterial activity. J Infect, 1995 Sep, 31(2), 89 - 92 Xanthomonas maltophilia and Pseudomonas cepacia in lower respiratory tracts of patients in critical care units; Maningo E et al.; Xanthomonas maltophilia and Pseudomonas cepacia are Gram-negative bacilli that are considered to opportunistic pathogens . These bacteria may cause colonization and infection, especially in acutely ill patients . Between 1 July 1990 and 30 June 1992 sputum {correction of suptum} culture results from patients in the critical care units were surveyed daily . During the 2 year period, sputum from 27 patients grew X . maltophilia . It was hospital-acquired in 26 patients . A total of 26 patients were mechanically ventilated for between 1 day and 8 months (median 19 days) before sputum cultures grew X . maltophilia . Various antimicrobial agents were prescribed for 25 of the 27 patients before they acquired X . maltophilia infection . The case fatality was 44.4% . Sputum from 79 patients grew P . cepacia . It was hospital-acquired in all who were ventilated for between 1 day and 50 days (median 9 days) before sputum cultures grew P . cepacia . Several antimicrobial agents were given to 77 patients before P . cepacia was isolated from them . The case fatality rate was 51.9% . In the majority of cases, the positive cultures indicated colonization . Patients with APACHE II scores >15 experienced a higher fatality (55.6% vs . 22.2%, P<0.05 for X . maltophilia and 56.9% vs.28.6%, P<0.05 for P . cepacia). Glycobiology, 1995 Sep, 5(6), 603 - 10 A novel beta-galactosidase gene isolated from the bacterium Xanthomonas manihotis exhibits strong homology to several eukaryotic beta-galactosidases; Taron CH et al.; The gene encoding a beta-galactosidase from Xanthomonas manihotis was cloned into Escherichia coli . The gene resides on a 2.4 kb DNA fragment which was isolated from a partial Sau3A library in the cloning vector pUC19 using 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) as the selection . The enzyme produced by the clone has a specificity for beta 1-3- > beta 1-4-linked galactose . The nucleotide sequence of the gene was determined . The deduced protein sequence contained 597 amino acids yielding a monomeric molecular mass of 66 kDa . The cloned beta-galactosidase showed no similarity to any known prokaryotic beta-galactosidase . However, extensive similarity was observed with eukaryotic beta-galactosidases from animals, plants and fungi . The strongest similarity was with the beta-galactosidases found in the human and mouse lysosomes (42 and 41% identity, respectively) . Alignment of the X.manihotis and eukaryotic beta-galactosidase sequences revealed seven highly conserved domains common to each protein . Additionally, Domain 1 in X.manihotis showed similarity to regions within catalytic domains from seven xylanases and cellulases belonging to family 10 of glucosyl hydrolases . A region spanning Domain 2 showed similarity to the catalytic domain of endo beta 1-3 glucanases from tobacco and barley. J Bacteriol, 1995 Sep, 177(17), 4963 - 8 Intragenic recombination of a single plant pathogen gene provides a mechanism for the evolution of new host specificities; Yang Y et al.; Gene pthA is required for virulence of Xanthomonas citri on citrus plants and has pleiotropic pathogenicity and avirulence functions when transferred to many different xanthomonads . DNA sequencing revealed that pthA belongs to a family of Xanthomonas avirulence/pathogenicity genes characterized by nearly identical 102-bp tandem repeats in the central region . By inserting an nptI-sac cartridge into the tandemly repeated region of pthA as a selective marker, intragenic recombination among homologous repeats was observed in both Xanthomonas spp . and Escherichia coli . Intragenic recombination within pthA created new genes with novel host specificities and altered pathogenicity and/or avirulence phenotypes . Many pthA recombinants gained or lost avirulence function in pathogenicity assays on bean, citrus, and cotton cultivars . Although the ability to induce cell division (hyperplastic cankers) on citrus could be lost, this ability was not acquired on cotton or bean plants . Intragenic recombination therefore provides a genetic mechanism for the generation of multiple, different, and gratuitous avirulence genes from a single, required, host-specific pathogenicity gene. Mol Plant Microbe Interact, 1995 Sep-Oct, 8(5), 778 - 80 Lipopolysaccharide from Xanthomonas campestris induces defense-related gene expression in Brassica campestris; Newman MA et al.; Purified lipopolysaccharide (LPS) from Xanthomonas campestris pv . campestris induced accumulation of transcript for beta-1,3-glucanase in turnip at concentrations of 1 micrograms/ml . The lipid A-inner core structure was required for activity but the O-antigen had no role . We suggest that release of LPS in planta triggers expression of at least some defense-related genes. Mol Plant Microbe Interact, 1995 Sep-Oct, 8(5), 768 - 77 A locus determining pathogenicity of Xanthomonas campestris is involved in lipopolysaccharide biosynthesis; Dow JM et al.; A pathogenicity locus in Xanthomonas campestris pv . campestris has been shown to comprise two genes which mediate biosynthesis of the bacterial lipopolysaccharide (LPS) but not extracellular polysaccharide . Mutants with Tn5 insertions in either gene showed alterations in the electrophoretic patterns of both water-soluble and phenol-soluble LPS forms, which suggested defects in the biosynthesis of the core oligosaccharide component . On gel chromatography, core oligosaccharides of the mutants were of apparently lower molecular weight than those from the wild type . Furthermore, the content of mannose and glucose, sugars characteristic of the core oligosaccharide, were significantly lower in the water-soluble LPS of the mutants . Because of their role in LPS core biosynthesis, the two genes were called rfaX and rfaY . rfaX mutants show altered behavior in a range of host and non-host plants such that the number of recoverable bacteria drop within the first 24 h after inoculation . In contrast, the behavior of rfaY mutants only differed from the wild type in Datura, a non-host plant in which the growth of the wild type is severely attenuated . The predicted protein RfaY showed significant sequence homology to a sub-family of RNA polymerase sigma factors which are involved in extracytoplasmic functions. Microbiology, 1995 Sep, 141 ( Pt 9), 2253 - 60 Fructose phosphotransferase system of Xanthomonas campestris pv . campestris: characterization of the fruB gene; de Crecy-Lagard V et al.; In the plant pathogen Xanthomonas campestris pv . campestris, fructose is transported by a specific phosphotransferase system (PTS) . This PTS involves a multiphosphoryl transfer protein (MTP) encoded by the fruB gene, which was cloned and sequenced . fruB is part of a transcriptional unit together with the fruK gene, coding for 1-phosphofructokinase, which is located upstream from the fruA gene, coding for the fructose-specific permease (EIIB'BCFru) . The amino acid sequence of the X . campestris MTP deduced from the fruB sequence shared 46% identical residues with an MTP identified in Rhodobacter capsulatus . The X . campestris MTP (837 amino acid residues) consists of three moieties: a fructose-specific enzyme-IIA-like N-terminal moiety (residues 1-148), followed by an HPr-like moiety (161-251) and an enzyme-I-like C-terminal moiety (274-837) . The three domains are separated by two flexible hinge regions rich in proline and alanine residues . The construction of a fruB mutant confirmed the role of the MTP in fructose transport and phosphorylation in X . campestris. Carbohydr Res, 1995 Aug 11, 272(2), 225 - 30 Structure of the O6 antigen of Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia; Winn AM et al.; A polysaccharide containing D-xylose, L-rhamnose, and N-acetyl-D-glucosamine was released on mild acid hydrolysis of the lipopolysaccharide extracted from defatted cell walls of Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia strain 557, the reference strain for serotype O6 . By means of NMR spectroscopy and chemical degradations, the repeating unit of the polymer was identified as a branched trisaccharide with the structure shown . {formula: see text} Antonie Van Leeuwenhoek, 1995 Aug, 68(2), 161 - 4 Xanthomonas campestris pv . parthenii pathovar nov . incitant of leaf blight of parthenium; Chand R et al.; A new bacterial leaf blight disease of parthenium (Parthenium hysterophorus L.) is described for the first time . The disease-causing bacterium was isolated and its morphological, physiological and biochemical characters were determined . The pathogenicity of bacterium is apparently limited only to parthenium . The pathogen was identified as Xanthomonas campestris pv . parthenii pathovar nov . on the basis of morphological, physiological, biochemical and pathogenic characteristics. J Antimicrob Chemother, 1995 Aug, 36(2), 317 - 26 Growth temperature-dependent variation of cell envelope lipids and antibiotic susceptibility in Stenotrophomonas (Xanthomonas) maltophilia; Rahmati-Bahram A et al.; Clinical isolates of Stenotrophomonas (Xanthomonas) maltophilia showed growth temperature-dependent variation in susceptibility (TDVS) to aminoglycoside antibiotics between 30 degrees C and 37 degrees C, but little or no TDVS effect for polymixin B, colistin, ceftazidime, chloramphenicol and piperacillin . When phenylethanol was added at sub-inhibitory concentrations, the TDVS effect was eliminated . Gas liquid chromatography showed that 13-methyl tetradecanoate (i-15;0), was the predominant fatty acid, and was present in lower proportions in cells grown at 30 degrees C than 37 degrees C, by contrast to the unsaturated acids, which were found in increased proportions in cells grown at 30 degrees C . However, the extent of these shifts in composition did not correlate with the extent of the TDVS effect in individual strains . Membrane analysis by spin label-electron spin resonance spectroscopy showed that strains exhibiting TDVS had significantly decreased membrane fluidity compared with susceptible strains at 30 degrees C . Furthermore, analysis of the outer and cytoplasmic membranes from the strains with TDVS revealed that in organisms grown at 30 degrees C, the outer membrane remained in a more rigid conformation than the cytoplasmic membrane . We conclude that resistance of S . maltophilia to aminoglycoside antibiotics at 30 degrees C correlates with changes in the conformation of the outer membrane so that binding and/or uptake of the antibiotic is inhibited. J Clin Microbiol, 1995 Aug, 33(8), 2195 - 8 Molecular typing of Stenotrophomonas (Xanthomonas) maltophilia by DNA macrorestriction analysis and random amplified polymorphic DNA analysis; Yao JD et al.; Stenotrophomonas (Xanthomonas) maltophilia is a multidrug-resistant, nosocomial pathogen for which optimal typing methods in epidemiologic investigations of nosocomial outbreaks have not been defined . We compared DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) with random amplified polymorphic DNA (RAPD) analysis by arbitrarily primed PCR for molecular typing of 109 multidrug-resistant strains of S . maltophilia from multiple outbreaks at our institution over a 10-month period in 1993 . PFGE after digestion with restriction endonuclease DraI revealed 62 unique DNA restriction profiles among the 109 strains, with 23, 11, 6, 6, and 3 strains having concordant profiles in each of five types . There were four concordant profiles among 8 strains (2 strains with each profile), while unique profiles were present in each of the remaining 52 strains . Further RAPD analysis with a decanucleotide primer showed the same number of distinct strain types as PFGE but more subtype diversity within each clonal type . We concluded that DNA macrorestriction analysis and RAPD analysis are sufficiently discriminatory and useful for differentiation of S . maltophilia strains in epidemiologic investigations of nosocomial outbreaks . However, RAPD analysis by arbitrarily primed PCR is faster and less laborious method of molecular typing. J Hosp Infect, 1995 Aug, 30(4), 309 - 13 Nosocomial and community-acquired Xanthomonas maltophilia infection in tropical Australia; Heath T et al.; Xanthomonas maltophilia infection is recognized as a serious problem in association with immunosuppressive and invasive therapies, and with the use of broad-spectrum antibiotics . In Darwin Hospital in Australia's Northern Territory preliminary evidence of nosocomial transmission of X . maltophilia prompted this retrospective examination of all X . maltophilia isolates over a 30 month period . X . maltophilia was most frequently isolated in the 'wet season' corresponding to times of increased antibiotic treatment of the serious community-acquired pneumonias encountered in this tropical region . A relatively high proportion of community-acquired isolates (4/18; 22%) was documented . This study demonstrates that X . maltophilia infection is an emerging cause of morbidity in tropical regions where endemic infections require the use of broad-spectrum beta-lactams. FEBS Lett, 1995 Jul 10, 368(1), 113 - 6 Structure of an acidic polysaccharide present in the bacteriolytic complex lysoamidase; Likhosherstov LM et al.; The structure of an acidic polysaccharide component of a bacteriolytic complex (lysoamidase), isolated from a bacterium of the genus Xanthomonas, was studied . On the basis of sugar analysis and one- and two-dimensional 1H and 13C NMR spectroscopic study of the initial polysaccharide and its O-deacetylated and carboxyl-reduced derivatives, the following structure of the trisaccharide repeating unit of the polysaccharide was established {formula: see text} where ManNAcA and GalNAcA are 2-acetamido-2-deoxymannuronic acid and 2-acetamido-2-deoxygalacturonic acid, respectively. Rev Argent Microbiol, 1995 Jul-Sep, 27(3), 146 - 55 {Isolation of xanthan from Xanthomonas campesteris B-1459 in mechanically agitated fermentors}; Lorda GS et al.; Xanthan production from Xanthomonas campestris was studied by a mechanically shaken fermentor . Influence of glucose concentration, aeration of culture media, rheology of broths and pH control was evaluated . Different aeration conditions based on variation of stirring rates were assayed . Substrate concentration was determined according to the Miller method, and polymer production was performed by the Cadmus method . The higher xanthan levels (i.e . 2.3%) were obtained at 750 rpm, with 1 v/v . min . In such conditions, viscosity ranges about 7000 cPoise and a low level of dissolved oxygen were detected in the culture medium . Xanthan production was influenced by the glucose concentration and the presence of amaranth within the culture medium . In the processes wherein an automatic control of pH was performed, the polymer concentration did not increase regarding to processes involving regular pH evolution. J Bacteriol, 1995 Jul, 177(14), 3932 - 9 A specific PulD homolog is required for the secretion of paracrystalline surface array subunits in Aeromonas hydrophila; Thomas SR et al.; Aeromonas hydrophila is an important pathogen of fish, and its high-virulence strains display a two-dimensional paracrystalline layer (S-layer) on their outermost surfaces . The nucleotide sequence of a 4.1-kb region located 700 bp upstream of the A . hydrophila TF7 S-layer protein gene (ahsA) has been determined . A sequence analysis of the region revealed the presence of three complete open reading frames ending in a gene encoding a 79.8-kDa polypeptide that shows high homology to the PulD family of secretion proteins . The sequenced region displays both organizational and sequence homology to the Xanthomonas campestris pv . campestris Xps secretory system . Insertional inactivation of the spsD (S-protein secretion D) gene showed that the loss of expression of the PulD homolog coincided with the localization of the S-protein in the periplasm and the loss of the S-layer from the surface of the bacterium . However, the secretion of the enzymes hemolysin, amylase, and protease was unaffected in the mutant with the nonfunctional spsD gene, as was the export of flagella and fimbrial proteins . Southern blot analysis showed that the spsD gene was not conserved among all strains of S-protein-producing A . hydrophila or Aeromonas veronii biotype sobria . Use of the promoterless chloramphenicol acetyltransferase gene showed that unlike pulD and its homologs, spsD contains its own promoter . A . hydrophila has been shown to contain the exe operon, which is responsible for the secretion of a number of extracellular enzymes in this bacterium . A fragment of DNA was generated from the exeD gene of A . hydrophilia Ah65 by PCR and was subsequently used in hybridization studies to probe the chromosome of A . hydrophila TF7 . The presence of an exeD homolog in A . hydrophila TF7 was found; therefore, the spsD gene encodes a second pulD homolog that displays a high specificity for the secretion of the S-protein . This gene appears to be part of a second terminal branch of the general secretory pathway in A . hydrophila. Clin Diagn Lab Immunol, 1995 Jul, 2(4), 448 - 53 Oligonucleotide primers designed to differentiate pathogenic pseudomonads on the basis of the sequencing of genes coding for 16S-23S rRNA internal transcribed spacers; Tyler SD et al.; Universal primers targeting conserved sequences flanking the 3' end of the 16S and the 5' end of the 23S rRNA genes (rDNAs) were used to amplify the 16S-23S rDNA internal transcribed spacers (ITS) from eight species of pseudomonads which have been associated with human infections . Amplicons from reference strains of Pseudomonas aeruginosa, Pseudomonas cepacia, Pseudomonas gladioli, Pseudomonas mallei, Pseudomonas mendocina, Pseudomonas pickettii, Pseudomonas pseudomallei, and Xanthomonas maltophilia were cloned from each species, and sequence analysis revealed a total of 19 distinct ITS regions, each defining a unique sequevar with ITS sizes ranging from 394 (P . cepacia) to 641 (P . pseudomallei) bp . Five distinct ITS sequevars in P . cepacia, four in P . mendocina, three in P . aeruginosa, two each in P . gladioli and P . pseudomallei, and one each in P . mallei, P . pickettii, and X . maltophilia were identified . With the exception of one P . cepacia ITS, all ITS regions contained potential tRNA sequences for isoleucine and/or alanine . On the basis of these ITS sequence data, species-specific oligonucleotide primers were designed to differentiate P . aeruginosa, P . cepacia, and P . pickettii . The specificities of these primers were investigated by testing 220 clinical isolates, including 101 strains of P . aeruginosa, 103 strains of P . cepacia, and 16 strains of P . pickettii, in addition to 24 American Type Culture Collection (ATCC) Pseudomonas strains . The results showed that single primer pairs directed at particular ITSs were capable of specifically identifying the ATCC reference strains and all of the clinical isolates of P . aeruginosa and P . pickettii, but this was not the case with several ITS-based primer pairs tested for P . cepacia . This pathogen, on the other hand, could be specifically identified by primer pairs directed against the 23S rDNA. Microbiology, 1995 Jun, 141 ( Pt 6), 1395 - 406 Subcellular location of XpsD, a protein required for extracellular protein secretion by Xanthomonas campestris pv . campestris; Hu NT et al.; The last ORF of an xps gene cluster, designated xpsD, is required for the secretion of extracellular enzymes across the outer membrane in Xanthomonas campestris pv . campestris . It could encode a protein of 759 amino acid residues . A consensus N-terminal lipoprotein signal peptide was revealed from its deduced amino acid sequence . A {3H}palmitate labelling experiment indicated that XpsD was fatty-acylated . Differential extraction with Triton X-100 disclosed that XpsD was fractionated with the outer membrane . Sucrose gradient sedimentation analysis of total membranes also indicated that XpsD was mainly located in the outer membrane . At least part of XpsD is exposed to the cell surface as suggested by trypsin experiment results . Intact cells pretreated with antibody against XpsD could indirectly be labelled with fluorescent agent . When the N-terminal lipoprotein signal peptide was replaced with a nonlipoprotein signal peptide cleavable by signal peptidase I, non-fatty-acylated XpsD was synthesized . Its subcellular location was indistinguishable from that of the fatty-acylated XpsD . Complementation of an xpsD::Tn5 mutant of X . campestris pv . campestris indicated that this non-fatty-acylated XpsD remains functional in extracellular protein secretion . A stable, C-terminal truncated protein, XpsD delta 414-759, was synthesized from a mutated xpsD gene . Although it stayed associated with the outer membrane and exposed to the cell surface, it no longer could complement the xpsD::Tn5 mutant of X . campestris pv . campestris. Gene, 1995 May 26, 158(1), 73 - 6 Characterization of an open reading frame involved in site-specific integration of filamentous phage Cf1t from Xanthomonas campestris pv . citri; Shieh GJ et al.; Cf1t is a single-stranded DNA filamentous phage; a 1.9-kb segment of DNA from Cf1t was found to be responsible for site-specific integration into Xanthomonas campestris pv . citri (XW47), in the absence of any Xanthomonas origin of replication . Deletion analysis and introduction of amber stop codons into this fragment from Cf1t revealed an open reading frame (ORF344) which was involved in the integration function . The predicted amino-acid sequence of ORF344 bears no homology with conserved sequences of the integrase family. J Clin Microbiol, 1995 May, 33(5), 1289 - 91 Genomic fingerprinting of epidemic and endemic strains of Stenotrophomonas maltophilia (formerly Xanthomonas maltophilia) by arbitrarily primed PCR; VanCouwenberghe CJ et al.; Arbitrarily primed PCR (AP-PCR) was used to type 64 clinical isolates of Stenotrophomonas maltophilia from 60 patients and the hands of one nurse . Forty-seven different patterns were observed, most patients having isolates with unique genomic fingerprints . A single pattern, however, was obtained from six of eight patients involved in an intensive care nursery outbreak, confirming the suspected nosocomial transmission of this microorganism . This strain was also found in four other patients hospitalized at the same time but in different units . AP-PCR typing results had a good correlation with the 49 patterns obtained when the isolates were typed by contour-clamped homogeneous electric field gel electrophoresis . Although AP-PCR is slightly less discriminatory than contour-clamped homogeneous electric field gel electrophoresis, it offers several advantages and should be considered as a practical option for molecular typing during investigations of outbreaks. J Clin Microbiol, 1995 May, 33(5), 1428 - 30 Comparison of E test and agar dilution for antimicrobial susceptibility testing of Stenotrophomonas (Xanthomonas) maltophilia; Yao JD et al.; Currently recommended dilution test methods for the determination of antimicrobial susceptibility of Stenotrophomonas (Xanthomonas) maltophilia are labor-intensive and often impractical in many clinical laboratories . We compared the E test with the agar dilution method for susceptibility testing of 176 clinical isolates of S . maltophilia against 16 antimicrobial agents . The MICs obtained by E test correlated well with those determined by the agar dilution method, with an overall agreement of 94% . Very major and major errors occurred infrequently (0.6 to 2.9%) when testing beta-lactam agents, tobramycin, trimethoprim-sulfamethoxazole, and fluoroquinolones . The E test was found to be accurate and easy to perform . For most antimicrobial agents tested against S . maltophilia, the E test is an acceptable alternative susceptibility test method. Gene, 1995 Apr 14, 156(1), 75 - 8 Complete sequence of the gene encoding a chorionic gonadotropin-like protein from Xanthomonas maltophilia; Grover S et al.; Our laboratory has previously reported that: (i) Xanthomonas maltophilia (Xm) produces a protein which has immunological resemblance to the beta-subunit of human chorionic gonadotropin (hCG) and (ii) possesses a high-affinity receptor which binds holo hCG, and the endogenous ligand, Xm chorionic gonadotropin (xCG), but does not bind human luteinizing hormone (hLH) . We have also previously published a 492-bp partial nucleotide sequence of the gene (xcg) coding for xCG . We report herein the entire xcg sequence of 1362 bp, which codes for a 48-kDa protein . This sequence confirmed the 492-bp sequence, as well as two partial amino acid (aa) sequences which we have previously reported . The sequence has a region which is homologous to aa 56-139 of the beta-subunit of hCG, and a second region homologous to the C-terminal tail of hCG . This is the first report of a prokaryotic gene homologous to the hCG beta-subunit-encoding gene. Plant Physiol, 1995 Apr, 107(4), 1333 - 41 Rice cationic peroxidase accumulates in xylem vessels during incompatible interactions with Xanthomonas oryzae pv oryzae; Young SA et al.; A cationic peroxidase, PO-C1 (molecular mass 42 kD, isoelectric point 8.6), which is induced in incompatible interactions between the vascular pathogen Xanthomonas oryzae pv oryzae and rice (Oryza sativa L.), was purified . Amino acid sequences from chemically cleaved fragments of PO-C1 exhibited a high percentage of identity with deduced sequences of peroxidases from rice, barley, and wheat . Polyclonal antibodies were raised to an 11-amino acid oligopeptide (POC1a) that was derived from a domain where the sequence of the cationic peroxidase diverged from other known peroxidases . The anti-POC1a antibodies reacted only with a protein of the same mobility as PO-C1 in extracellular and guttation fluids from plants undergoing incompatible responses collected at 24 h after infection . In the compatible responses, the antibodies did not detect PO-C1 until 48 h after infection . Immunoelectron microscopy was used to demonstrate that PO-C1 accumulated within the apoplast of mesophyll cells and within the cell walls and vessel lumen of xylem elements of plants undergoing incompatible interactions. Chemotherapy, 1995 Mar-Apr, 41(2), 121 - 4 Clinical isolate of a Xanthomonas maltophilia strain producing L-1-deficient and L-2-inducible beta-lactamases; Bonfiglio G et al.; Xanthomonas maltophilia produces two inducible beta-lactamases, L-1 and L-2, and resists the antimicrobial activity of beta-lactam antibiotics including carbapenems . L-1 has carbapenemase activity and L-2 is a cephalosporinase . It has been suggested that these beta-lactamases share regulatory components . We isolated a recent clinical X . maltophilia strain susceptible to carbapenems and resistant to almost all the other beta-lactam antibiotics tested . beta-Lactamase induction with cefotaxime showed that the clinical isolate had low-level expression of L-1 beta-lactamase but remained inducible for L-2 enzyme . The possible relationship of this enzyme to carbapenem sensitivity is considered. J Clin Microbiol, 1995 Mar, 33(3), 513 - 8 Molecular epidemiology of Xanthomonas maltophilia colonization and infection in the hospital environment; Laing FP et al.; Between April 1992 and December 1993, 80 Xanthomonas maltophilia isolates were collected from 63 patients in three acute-care hospitals in Calgary, Alberta, Canada . On the basis of Centers for Disease Control and Prevention definitions, 48 patients had nosocomial and 15 had community-acquired X . maltophilia . Thirty-eight of the patients were colonized and 25 were infected . Sixty-four percent of patients who acquired X . maltophilia in the intensive care unit (ICU) became infected, whereas 32% of patients in a non-ICU setting became infected . ICU patients tended to be hospitalized for a shorter period of time than non-ICU patients before the onset of X . maltophilia infection . Regardless of being colonized or infected, all patients had debilitating conditions, with respiratory disease being the most common underlying illness (35%) . Forty-two patients (88%) with hospital-acquired X . maltophilia received prior antibiotic therapy which included gentamicin, tobramycin, ceftazidime, piperacillin, and imipenem . Agar dilution MICs showed that patient isolates were resistant to these antimicrobial agents that patients had received . Pulsed-field gel electrophoresis of SpeI-digested genomic DNA revealed that six epidemiologically linked patient isolates from the ICU of one acute-care hospital had identical DNA profiles . In contrast, isolates from patients from the other two hospitals had unique genotype profiles (n = 57) regardless of the presence or absence of an epidemiologic association . In these patients there was genetic evidence against the acquisition of a resident hospital clone . These results indicate that pulsed-field gel electrophoresis can resolve genotypically distinct strains of X . maltophilia and, consequently, is a useful tool for evaluating nosocomial infections caused by X . maltophilia. Biochem Biophys Res Commun, 1995 Feb 6, 207(1), 223 - 30 Nucleotide sequence and expression of UDP-glucose dehydrogenase gene required for the synthesis of xanthan gum in Xanthomonas campestris; Lin CS et al.; Xanthomonas campestris pv . campestris, producing large amounts of exopolysaccharide xanthan gum, has a mucoid phenotype . Strain SD7 was a non-mucoid mutant deficient in UDP-glucose dehydrogenase . A DNA fragment able to complement the mutation of SD7 was cloned from the parental wild-type strain Xc11 . Sequence analysis of the region required for the complementation revealed an open reading frame which could encode a polypeptide of 445 amino acids with a calculated molecular weight of 48,432, a size similar to that of the product produced by maxicell . The amino acid sequence had significant homology to that of the GDP-mannose dehydrogenase from Pseudomonas aeruginosa. Glycobiology, 1995 Feb, 5(1), 19 - 28 Purification and characterization of novel glycosidases from the bacterial genus Xanthomonas; Wong-Madden ST et al.; Enzymatic analysis of oligosaccharides using exoglycosidases has become a powerful tool for determining the sequence and structure of sugar chains . The principal limitation to these methods has been the lack of highly purified and well-characterized enzymes . Using fluorescently labelled carbohydrate substrates and TLC, we have developed a method to identify glycosidases with novel specificities . This screening method led to the discovery that bacteria of the genus Xanthomonas are a rich source of exoglycosidases . From Xanthomonas manihotis, eight novel exoglycosidases have been isolated and characterized . A novel beta-N-acetylglucosaminidase has been purified that, unlike those previously described, will cleave N-acetylglucosamine without cleaving N-acetylgalactosamine residues . A novel beta-galactosidase has been isolated that preferentially hydrolyses beta(1-->3) galactosyl linkages . Three alpha-mannosidases have been isolated that serve as useful reagents in the analysis of high-mannose oligosaccharide structures: alpha 1-3,6 mannosidase, alpha 1-6 mannosidase and alpha 1-2,3 mannosidase . An alpha 1-3,6 galactosidase has been purified that does not hydrolyse terminal alpha 1-4 galactose residues . Two fucosidases, alpha 1-3,4 fucosidase and alpha 1-2 fucosidase, are similar to enzymes purified from other sources . Together, these glycosidases provide powerful reagents for determining the sequence of complex carbohydrates . Equally important is their usefulness in selectively removing specific sugar residues and thereby creating novel carbohydrates for analysing the biological roles of oligosaccharides. Biosci Biotechnol Biochem, 1995 Feb, 59(2), 298 - 301 Prolylcarboxypeptidase (angiotensinase C): purification and characterization of the enzyme from Xanthomanas maltophilia; Suga K et al.; Prolylcarboxypeptidase (Angiotensinase C, EC 3.4.16.2) was purified to homogeneity from cell free extracts of Xanthomonas maltophilia by ammonium sulfate fractionation and sequential chromatographies on DEAE-Toyopearl, Sephadex G-150, FPLC-Hiload Superdex 200 pg, and FPLC-Hitrap SP columns, with an activity recovery of 15% . The molecular weight of the enzyme was found to be 330,000 by gel filtration and 83,000 by SDS-PAGE, suggesting a tetrameric form for the native enzyme . It had an optimum pH of 8.5 and stability between pH 8.0 and 11.0 . The isoelectric point of the enzyme was 6.6 . The enzyme hydrolyzed Pro-X bonds when proline was in the penultimate position from the carboxyl terminal . The enzyme was strongly inhibited by diisopropylfluorophosphate (DFP), while phenylmethylsulfonyl fluoride (PMSF), p-chloromercuribenzoic acid (PCMB), iodoacetamide, and metal chelators had no effect. Eur J Clin Microbiol Infect Dis, 1995 Feb, 14(2), 137 - 40 Diversity of nosocomial Xanthomonas maltophilia (Stenotrophomonas maltophilia) as determined by ribotyping; Gerner-Smidt P et al.; Seventy-seven clinical isolates of Xanthomonas maltophilia (Stenotrophomonas maltophilia) were consecutively collected from the Rigshospitalet, Copenhagen, ribotyped and compared with the ribotypes of 25 other clinical and reference strains of Xanthomonas maltophilia . Using restriction enzyme EcoRI, 20 different ribotypes were observed, with 78 isolates displaying the five most common types . Using another enzyme, BamHI, these 78 isolates were further subdivided into 16 different ribotypes . Three patients harboured two strains with different ribotypes . No type was found related to only one department and no single-strain outbreak was detected . The origin of this wealth of different strains in hospital patients needs to be established. Clin Infect Dis, 1995 Feb, 20(2), 445 - 8 Xanthomonas maltophilia misidentified as Pseudomonas cepacia in cultures of sputum from patients with cystic fibrosis: a diagnostic pitfall with major clinical implications; Burdge DR et al.; Pseudomonas cepacia infection in patients with cystic fibrosis (CF) has major significance in terms of infection control, psychosocial issues, and medical treatment . We describe three instances in which the diagnostic laboratory misidentified Xanthomonas maltophilia as P . cepacia in cultures of sputum from patients with CF . These errors were recognized when 3 (9%) of 32 isolates, which had all been identified as P . cepacia and had been submitted to the Canadian Pseudomonas Repository Laboratory (Vancouver, BC), were correctly identified there as X . maltophilia . Each of the three isolates grew well on P . cepacia media, turned a characteristic vivid pink color, were polymyxin-resistant, and were lysine-positive . All three were initially characterized incorrectly as oxidase-positive and DNase-negative . The diagnostic laboratory then reexamined 24 other isolates that had been identified as P . cepacia; complete biochemical testing confirmed that all were indeed P . cepacia . Because infection due to P . cepacia has major implications for patients with CF, when a possible strain of P . cepacia is isolated, careful and complete characterization should be performed. Carbohydr Res, 1995 Feb 1, 267(1), 127 - 33 Structure of the O10 antigen of Stenotrophomonas (Xanthomonas) maltophilia; Winn AM et al.; A polysaccharide containing L-rhamnose and L-xylose was isolated from the lipopolysaccharide extracted from the cell walls of the reference strain for Stenotrophomonas (Xanthomonas) maltophilia serogroup O10 . By means of NMR studies and methylation analysis, the repeating unit of the polymer was identified as a branched tetrasaccharide of the structure shown . {formula: see text} Adv Exp Med Biol, 1995, 390, 71 - 80 A low-copy number plasmid mediating beta-lactamase production by Xanthomonas maltophilia; Kelly MD et al.; To delineate the mechanisms contributing to the high level of antimicrobial resistance often demonstrated by Xanthomonas maltophilia, plasmid DNA was isolated from 5 clinical isolates and analyzed . Purified plasmid DNA from a single isolate contained a 6.5 kb plasmid (pXM222) and a 5.6 kb plasmid, (pTHB) . Transformation of pTHB into E . coli HB101 resulted in the expression of resistance to all penicillins tested and cefazolin. J Antimicrob Chemother, 1995 Jan, 35(1), 167 - 71 The role of lipopolysaccharide anionic binding sites in aminoglycoside uptake in Stenotrophomonas (Xanthomonas) maltophilia; Vanhoof R et al.; Aminoglycoside resistance was investigated in six clinical isolates of Stenotrophomonas (Xanthomonas) maltophilia by studying the uptake kinetics and by using a radiochemical method to detect aminoglycoside modifying enzymes . Furthermore, the lipopolysaccharides (LPS) were extracted and characterized by SDS-PAGE and chemical analysis . Dansyl-polymyxin displacement experiments confirmed the availability of anionic binding sites . Growing cells of the isolates bound dansyl-polymyxin but were not lysed. Antimicrob Agents Chemother, 1995 Jan, 39(1), 192 - 9 Kinetic analysis of extension of substrate specificity with Xanthomonas maltophilia, Aeromonas hydrophila, and Bacillus cereus metallo-beta-lactamases; Felici A et al.; Twenty beta-lactam molecules, including penicillins, cephalosporins, penems, carbapenems, and monobactams, were investigated as potential substrates for Xanthomonas maltophilia ULA-511, Aeromonas hydrophila AE036, and Bacillus cereus 5/B/6 metallo-beta-lactamases . A detailed analysis of the kinetic parameters examined confirmed these enzymes to be broad-spectrum beta-lactamases with different ranges of catalytic efficiency . Cefoxitin and moxalactam, substrates for the beta-lactamases from X . maltophilia ULA-511 and B . cereus 5/B/6, behaved as inactivators of the A . hydrophila AE036 metallo-beta-lactamase, which appeared to be unique among the enzymes tested in this study . In addition, we report a new, faster, and reliable purification procedure for the B . cereus 5/B/6 metallo-beta-lactamase, cloned in Escherichia coli HB101. DNA Seq, 1995, 5(5), 299 - 305 A homolog of an Escherichia coli phosphate-binding protein gene from Xanthomonas oryzae pv . oryzae; Hopkins CM et al.; A Xanthomonas oryzae pv . oryzae gene with sequence similarity to an Escherichia coli phosphate-binding protein gene (phoS) produces a periplasmic protein of apparent M(r) 35,000 when expressed in E . coli . Amino terminal sequencing revealed that a signal peptide is removed during transport to the periplasm in E . coli. Ann Intern Med, 1994 Dec 15, 121(12), 969 - 73 Mucocutaneous and soft tissue infections caused by Xanthomonas maltophilia . A new spectrum; Vartivarian SE et al.; OBJECTIVE: To describe the mucocutaneous and soft tissue infections caused by Xanthomonas maltophilia in patients with cancer . DESIGN: A retrospective 15-month clinical study . SETTING: Academic, referral-based cancer center . PATIENTS: Of 237 patients with X . maltophilia isolated from all sites during the 15-month study period, 114 patients were judged to have true X . maltophilia infections . Only patients with mucocutaneous and soft tissue infections were included in the study . RESULTS: 17 (15%) of the 114 patients with X . maltophilia infection had mucocutaneous and soft tissue infections: Six patients had metastatic cellulitis, 5 had primary cellulitis usually associated with catheter use, and 6 had infected mucocutaneous ulcers . The metastatic cellulitis consisted of previously undescribed multiple, hard, tender nodules with surrounding and distant cellulitis (5 patients) or ecthyma gangrenosum (1 patient) . Four of these patients died of the infection . Metastatic cellulitis and mucocutaneous infections occurred in hospitalized, neutropenic patients who received broad-spectrum antibiotics (beta-lactams, quinolones), often with in vitro activity against the infecting organisms . Response usually correlated with recovery from myelosuppression and administration of trimethoprim-sulfamethoxazole with or without ticarcillin-clavulanate . Catheter removal contributed to response in the treatment of primary cellulitis . CONCLUSIONS: Mucocutaneous and soft tissue infections caused by X . maltophilia are not uncommon, and X . maltophilia can cause metastatic nodular skin lesions that mimic disseminated fungal infections . It also causes serious morbidity and high mortality in patients with metastatic skin nodules and can cause superinfections in patients receiving broad-spectrum beta-lactam or quinolone antibiotics to which the organisms are susceptible when the infections develop . Catheter removal contributes to a favorable outcome in patients with catheter-associated cellulitis without bacteremia . Xanthomonas maltophilia infection should be added to the differential diagnosis of mucocutaneous or soft tissue infection in patients with cancer . Trimethoprim-sulfamethoxazole with or without ticarcillin-clavulanate is the current treatment of choice for culture-proven infections, but early empiric therapy may improve outcome. Biosci Biotechnol Biochem, 1994 Dec, 58(12), 2269 - 70 Enhancing effect of 4-hydroxy-3-nitrophenylacetic acid on transcription of the ice nucleation-active gene of Xanthomonas campestris; Watanabe M et al.; Cultivation of an ice nucleation-active strain of Xanthomonas campestris in the presence (1 ppm) of 4-hydroxy-3-nitrophenylacetic acid resulted in enhancement of its ice-nucleation activity . Both the ice-nucleation-active protein, InaX, and its mRNA were effectively expressed in the bacterial cells cultured in the presence of this compound . This indicates that this compound stimulated the biosynthesis of the ice-nucleation-active protein. Ugeskr Laeger, 1994 Nov 28, 156(48), 7229 - 30 {Xanthomonas maltophilia . A cause of epidural abscess in a patient with epidural catheterization}; Wagn P et al.; A case of epidural abscess following continuous spinal epidural catheterization is presented . The clinical signs included spinal ache, root pain, weakness and paralysis but no fever . Xanthomonas maltophilia, an organism closely related to Pseudomonas species, was the causative agent . This has not previously been described as the causative agent of epidural abscesses. Appl Environ Microbiol, 1994 Nov, 60(11), 4094 - 9 Sensitive and specific detection of Xanthomonas campestris pv . pelargonii with DNA primers and probes identified by random amplified polymorphic DNA analysis; Manulis S et al.; The random amplified polymorphic DNA method was used to distinguish strains of Xanthomonas campestris pv . pelargonii from 21 other Xanthomonas species and/or pathovars . Among the 42 arbitrarily chosen primers evaluated, 3 were found to reveal diagnostic polymorphisms when purified DNAs from compared strains were amplified by the PCR . The three primers revealed DNA amplification patterns which were conserved among all 53 strains tested of X . campestris pv . pelargonii isolated from various locations worldwide . The distinctive X . compestris pv . pelargonii patterns were clearly different from those obtained with any of 46 other Xanthomonas strains tested . An amplified 1.2-kb DNA fragment, apparently unique to X . campestris pv . pelargonii by these random amplified polymorphic DNA tests, was cloned and evaluated as a diagnostic DNA probe . It hybridized with total DNA from all 53 X . campestris pv . pelargonii strains tested and not with any of the 46 other Xanthomonas strains tested . The DNA sequence of the terminal ends of this 1.2-kb fragment was obtained and used to design a pair of 18-mer oligonucleotide primers specific for X . campestris pv . pelargonii . The custom-synthesized primers amplified the same 1.2-kb DNA fragment from all 53 X . campestris pv . pelargonii strains tested and failed to amplify DNA from any of the 46 other Xanthomonas strains tested . DNA isolated from saprophytes associated with the geranium plant also did not produce amplified DNA with these primers . The sensitivity of the PCR assay using the custom-synthesized primers was between 10 and 50 cells.(ABSTRACT TRUNCATED AT 250 WORDS) Plasmid, 1994 Nov, 32(3), 328 - 32 Replicon typing of plasmids of phytopathogenic xanthomonads; Amuthan G et al.; Replicon types of plasmids of phytopathogenic Xanthomonads have been identified . Plasmids of Xanthomonas oryzae pathovar oryzae belonged to types RepP, RepW, RepY, RepU, and RepF1 and 50% of the plasmids of different isolates of X.o.pv.oryzae belonged to type RepP . X.c.pv.citri contained plasmids belonging to RepF1 and RepF11 . Of the 19 replicon probes used, only 9 (repP, repF1, repF11, repY, repQ, repW, repX, and repU) hybridized with various plasmids of Xanthomonas. Mol Plant Microbe Interact, 1994 Nov-Dec, 7(6), 799 - 804 AVRXa10 protein is in the cytoplasm of Xanthomonas oryzae pv . oryzae; Young SA et al.; AVRXa10 from Xanthomonas oryzae pv . oryzae was tagged with a unique hydrophilic octapeptide (FLAG) to permit antibody-mediated identification and purification of the gene product . X . o . pv . oryzae that produced tagged AVRXa10 elicited a hypersensitive response (HR) on rice cultivars containing the resistance gene Xa-10, but not on cultivars lacking Xa-10 . The tagged AVRXa10 protein purified from Escherichia coli or X . o . pv . oryzae did not elicit a hypersensitive response in rice with the Xa-10 resistance gene . Anti-FLAG monoclonal antibodies reacted with a 119-kDa protein in both E . coli and X . o . pv . oryzae cells expressing the tagged avrXa10 gene . Polyclonal antibodies raised against purified AVRXa10 protein reacted with the 119-kDa protein and several additional proteins from X . o . pv . oryzae, which probably are the products of genes related to avrXa10 . Biochemical fractionation and immunoelectronmicroscopy analysis was used to demonstrate that AVRXa10 was located in the cytoplasm of X . o . pv . oryzae cells when grown in planta or in culture medium. Infect Control Hosp Epidemiol, 1994 Nov, 15(11), 691 - 6 Analysis of epidemic and endemic isolates of Xanthomonas maltophilia by contour-clamped homogeneous electric field gel electrophoresis; VanCouwenbergh C et al.; BACKGROUND: Xanthomonas maltophilia is increasingly a cause of nosocomial infections . The mode of transmission of this organism is not well known . OBJECTIVE: To investigate clonality of X maltophilia isolates in epidemic and endemic settings . METHODS: An outbreak of X maltophilia was noted in the Intensive Care Nursery (ICN) . Over the ensuing 9 months, hospital wide isolates of X maltophilia were analyzed using contour-clamped homogeneous electric field (CHEF) gel electrophoresis of chromosomal DNA . This method was compared with the antibiogram for detecting differences and similarities among strains . RESULTS: X maltophilia was recovered from 76 sites in 72 patients; 65 isolates from 61 patients and the hands of one nurse were available for analysis . CHEF demonstrated differences between most epidemiologically unrelated strains and similarity between most epidemiologically related strains . Several strains, initially presumed to be related because of temporal and spatial proximity of the patients involved, were determined by CHEF analysis to be independent infections . One pair of isolates whose XbaI CHEF patterns differed by a single band were differentiated clearly by SspI . There was enough variation in the minimum inhibitory concentrations of selected antibiotics to allow typing of some strains . The antibiogram, however, did not group all of the ICN outbreak isolates with others found to be genetically identical by CHEF, and it grouped 39 of 56 isolates with others not genetically the same . CONCLUSIONS: Although it is a convenient and economical tool, the antibiogram has limitations . Analysis by CHEF should help to elucidate the epidemiological spread of X maltophilia in the hospital. J Clin Microbiol, 1994 Nov, 32(11), 2856 - 7 Pneumonia caused by Stenotrophomonas maltophilia with a mucoid phenotype; Irifune K et al.; We describe the first known case of pneumonia caused by a mucoid Stenotrophomonas maltophilia (Xanthomonas maltophilia) strain in a patient with bronchiectasis . The patient was admitted because of mild hemoptysis and productive cough with infiltrative shadow in the right lower lung field on chest X ray . The clinical symptoms were mild, and treatment with minocycline was effective. Microbiology, 1994 Nov, 140 ( Pt 11), 3007 - 13 Gellan lyases--novel polysaccharide lyases; Kennedy L et al.; A number of bacterial strains capable of degrading the bacterial exopolysaccharide gellan have been isolated by standard enrichment procedures . They include several pink-pigmented Gram-negative rod-shaped bacteria . A red-pigmented Gram-positive bacillus earlier found to degrade the exopolysaccharide xanthan from Xanthomonas campestris also showed slight gellanase activity . All the Gram-negative bacteria are non-fermentative, motile and amylase-producing . The gellan degradation in each case is due to eliminase-type enzymes (lyases) which appear to be extracellular enzymes cleaving the sequence.. . beta-D-glucosyl-(1-->4)-beta-D-glucuronosyl.. . in the tetrasaccharide repeat unit of the substrate polysaccharides . Although in some isolates these enzymes appear to be exo-acting, it appears from the loss in viscosity of the alternative substrate deacetylated rhamsan that they are predominantly endoenzymes . The enzyme activity is inducible: it is almost absent from glucose-grown cells . Associated with the 'gellanase' activity, all the Gram-negative bacterial isolates possess intracellular alpha-L-rhamnosidase and beta-D-glucosidase activities apparently located in the periplasm . The enzymes are highly specific and fail to cause significant degradation of most of the other bacterial exopolysaccharides which have been shown to be structurally related to gellan . As well as acting on gellan, they exert similar degradative activity against the chemically deacylated form of polysaccharide S194 (rhamsan gum), which is effectively a gentiobiosylated form of gellan . The enzymes only have relatively slight activity against the natural, acylated gellan-like polysaccharides from the bacteria now designated as strains of Sphingomonas paucimobilis. J Appl Bacteriol, 1994 Nov, 77(5), 509 - 18 Production of monoclonal antibodies against Xanthomonas campestris pv . mangiferaeindicae and their use to investigate differences in virulence; Sanders GM et al.; Four Xanthomonas campestris pv . mangiferaeindicae isolates from mango black spot lesions were grouped according to differences in virulence and used to raise monoclonal antibodies (mAbs) . Two immunization approaches were followed . In the first, four groups of mice were immunized, each with a different isolate and the spleens from each group homogenized together for cell fusion . The second approach entailed immunization of a single group of mice with bacteria pooled from all four isolates . The resultant mAbs were characterized with regard to the antigen binding specificity and antibody class . A relationship between mAb binding specificity and virulence of the bacteria was shown by Western blot analysis. J Bacteriol, 1994 Oct, 176(20), 6229 - 37 Mechanism of bacitracin resistance in gram-negative bacteria that synthesize exopolysaccharides; Pollock TJ et al.; Four representative species from three genera of gram-negative bacteria that secrete exopolysaccharides acquired resistance to the antibiotic bacitracin by stopping synthesis of the exopolysaccharide . Xanthomonas campestris, Sphingomonas strains S-88 and NW11, and Escherichia coli K-12 secrete xanthan gum, sphingans S-88 and NW11, and colanic acid, respectively . The gumD gene in X . campestris is required to attach glucose-P to C55-isoprenyl phosphate, the first step in the assembly of xanthan . A recombinant plasmid carrying the gumD gene of X . campestris restored polysaccharide synthesis to bacitracin-resistant exopolysaccharide-negative mutants of X . campestris and Sphingomonas strains . Similarly, a newly cloned gene (spsB) from strain S-88 restored xanthan synthesis to the same X . campestris mutants . However, the intergeneric complementation did not extend to mutants of E . coli that were both resistant to bacitracin and nonproducers of colanic acid . The genetic results also suggest mechanisms for assembling the sphingans which have commercial potential as gelling and viscosifying agents. J Gen Virol, 1994 Sep, 75 ( Pt 9), 2543 - 7 Characterization of two novel filamentous phages of Xanthomonas; Lin NT et al.; Two filamentous phages of Xanthomonas campestris pv . vesicatoria and Xanthomonas oryzae pv . oryzae were isolated and designated phi Xv and phi Xo, respectively . They were similar to other filamentous phages of Xanthomonas in (i) shape, (ii) restrictive host specificity, (iii) high stability, (iv) an ssDNA genome, (v) a dsDNA as the replicative form (RF), (vi) propagation without lysis of host cells and (vii) ability to integrate into the host chromosome . These phages showed sequence homology to filamentous phage phi Lf of X . c . pv . campestris . phi Xv was inactivated by antisera against phi Xv, phi Xo and phi Lf, whereas phi Xo and phi Lf were inactivated only by their respective antisera and the anti-phi Xv serum . Both the single-stranded phage DNAs and the RF DNAs of phi Xv, phi Xo and phi Lf were able to transfect X . c . pv . vesicatoria, X . o . pv . oryzae and X . c . pv . campestris . Physical maps of phi Xv and phi Xo were constructed for the RF DNAs . Genome sizes were estimated, based on mapping data, to be 6.8 kb for phi Xv and 7.6 kb for phi Xo, larger than that of the phi Lf genome (6.0 kb) . The difference in genome sizes appeared to result from insertions of large DNA fragments . These fragments and the regions mediating integration were localized in the physical maps. Mol Plant Microbe Interact, 1994 Sep-Oct, 7(5), 677 - 9 Avirulence gene avrPphC from Pseudomonas syringae pv . phaseolicola 3121: a plasmid-borne homologue of avrC closely linked to an avrD allele; Yucel I et al.; Cosmid clone pPsp01 from race 1 Pseudomonas syringae pv . phaseolicola isolate 3121 conferred a unique pattern of soybean cultivar reactions when expressed in P . s . pv . glycinea R4 . The avirulence phenotype was shown to result from the presence in clone pPsp01 of an avrD allele as well as an additional avirulence gene located approximately 5-kb upstream . The new gene, called avrPphC, shows high identity to and is phenotypically identical to avrC, previously cloned from P . s . pv . glycinea race 0 . avrD and avrPphC occur on an approximately 120-kb indigenous plasmid in P . s . pv . phaseolicola 3121 . Although commonly observed in Xanthomonas campestris, this is the first noted occurrence of multiple avirulence genes on a single plasmid in Pseudomonas syringae . Unlike avrD, however, avrPphC does not appear to occur widely in pathovars of Pseudomonas syringae. Mol Plant Microbe Interact, 1994 Sep-Oct, 7(5), 553 - 63 Defense-related gene induction in Brassica campestris in response to defined mutants of Xanthomonas campestris with altered pathogenicity; Newman MA et al.; We have studied the induction of beta-1,3-glucanase (BGL) in turnip following inoculation with pathovars of Xanthomonas campestris and derived mutants . BGL transcript accumulated more rapidly in leaves in the incompatible interactions with X . c . pv . armoraciae and X . c . pv . raphani than in the compatible interaction with X . c . pv . campestris . No accumulation was seen in response to wounding or inoculation with water, salicylic acid, or Escherichia coli . Deletion of the hrp cluster from the X . campestris pathovars caused a reduction in the level of transcript accumulation; these effects were much more pronounced in the incompatible than in the compatible interaction, in which bacterial growth was also affected . In the compatible interaction, bacterial growth and BGL transcript accumulation were not altered by mutation of bacterial genes involved in the regulation of the synthesis of extracellular enzymes or their export from the cell, or by mutation of the structural genes for extracellular endoglucanase and serine protease . Mutation of genes involved in the synthesis of extracellular polysaccharide or lipopolysaccharide reduced bacterial survival in planta, so that the numbers were between two and three orders of magnitude lower than the number of wild-type bacteria . However, total BGL transcript accumulation after inoculation with these mutants was about 80% of that seen after inoculation with the wild-type bacteria, suggesting that one aspect of the role of extracellular polysaccharide and lipopolysaccharide in pathogenesis is to mask the presence of bacteria in the plant . Our results are discussed in the context of work on other plant-microbe interactions. Antimicrob Agents Chemother, 1994 Sep, 38(9), 2143 - 9 Biochemical properties of inducible beta-lactamases produced from Xanthomonas maltophilia; Paton R et al.; Four different beta-lactamases have been found in several strains of Xanthomonas maltophilia isolated from blood cultures during 1984 to 1991 at the Edinburgh Royal Infirmary . One was a metallo-beta-lactamase with predominantly penicillinase activity and an isoelectric point of 6.8 . Its molecular size as determined by gel filtration was 96 kDa but was only 26 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), suggesting a tetramer of four equal subunits . The enzyme hydrolyzed all classes of beta-lactams except the monobactam aztreonam . This enzyme was not inhibited by potassium clavulanate or BRL 42715 but was inhibited by p-chloromercuribenzoate, mercuric chloride, and EDTA . The beta-lactamase was unstable in 50 mM sodium phosphate buffer (pH 8.0) but stable in 50 mM Tris HCl (pH 8.0) . The other beta-lactamases focused as a series of different isoelectric points, ranging from pI 5.2 to 6.6 . Together, these enzymes exhibited a broad spectrum of activity, hydrolyzing most classes of beta-lactams but not imipenem or aztreonam . Their molecular size was 48 kDa by Sephadex gel filtration and 24 kDa by SDS-PAGE, indicating that they were enzymes consisting of two equal subunits . They were inhibited by p-chloromercuribenzoate, mercuric chloride, potassium clavulanate, and BRL 42715 but not EDTA . This study demonstrated that X . maltophilia produces more than just the L1 and L2 beta-lactamases. Gene, 1994 Aug 19, 146(1), 73 - 8 The sequence of the mer operon of pMER327/419 and transposon ends of pMER327/419, 330 and 05; Hobman J et al.; Three different, independently isolated mercury-resistance-conferring plasmids, pMER327/419, pMER330 and pMER05, from cultures originating from the river Mersey (UK), contain identical regulatory merR genes and transposon ends . The mer determinant from pMER327/419 contains an additional potential ORF (ORF F) located between merP and merA when compared with the archetypal Tn501 . Although these plasmids confer narrow-spectrum resistance (resistance to Hg2+, but not organomercurials) their merR genes encode a potential organomercurial-sensing protein . Transposition of the mer of pMER05 into plasmid RP4 was demonstrated and, as with Tn502 and Tn5053, insertion occurred at a specific region . The sequence of pMER05 is identical at the 'left' and 'right' termini and across merR to Tn5053, which was independently isolated from the chromosome of a Xanthomonas sp . bacteria from the Khaidarkan mercury mine in Kirgizia, former Soviet Union {Kholodii et al., J . Mol . Biol . 230 (1993a) 1103-1107} . The transpositional unit of pMER05 is, like that of Tn5053, bounded by DNA homologous to the imperfect 25-bp inverted repeats (IR) of the In2 integron, which brackets antibiotic-resistance cassettes in Tn21 subgroup transposons . At one end of the transposable element, and internal to the In2-like IR, is a 38-bp IR which closely resembles the IR that bounds Tn21. Mol Gen Genet, 1994 Aug 15, 244(4), 383 - 90 Identification of the XorII methyltransferase gene and a vsr homolog from Xanthomonas oryzae pv . oryzae; Choi SH et al.; The gene encoding the XorII methyltransferase (M.XorII) was cloned from Xanthomonas oryzae pv . oryzae and characterized in Escherichia coli . The M.XorII activity was localized to a 3.1 kb BamHI-BstXI fragment, which contained two open reading frames (ORFs) of 1272 nucleotides (424 amino acids) and 408 nucleotides (136 amino acids) . Ten polypeptide domains conserved in other M5 cytosine methyltransferases (MTases) were identified in the deduced amino acid sequence of the 1272 ORF . E . coli Mrr+ strains were transformed poorly by plasmids containing the XorII MTase gene, indicating the presence of at least one MCG in the recognition sequence for M.XorII (CGATCG) . The 408 nucleotide ORF was 36% identical at the amino acid level to sequences of the E . coli dem-vsr gene, which is required for very short patch repair . X . oryzae pv . oryzae genomic DNA that is resistant to digestion by PvuI and XorII hybridizes with a 7.0 kb fragment containing the XorII MTase gene and vsr homolog, whereas DNA from strains that lack M.XorII activity do not hybridize with the fragment. Clin Infect Dis, 1994 Aug, 19(2), 325 - 6 Meningitis due to Xanthomonas maltophilia: case report and review; Nguyen MH et al.; Xanthomonas maltophilia is being increasingly recognized as an opportunistic pathogen in debilitated patients . We report a case of postoperative meningitis due to X . maltophilia and review the cases of X . maltophilia meningitis reported in the literature . Because X . maltophilia is often resistant to multiple beta-lactam agents, including cephalosporins and imipenem, trimethoprim-sulfamethoxazole appears to be the drug of choice for treatment of X . maltophilia meningitis. FEMS Microbiol Rev, 1994 Aug, 14(4), 381 - 6 Molecular mechanisms of copper resistance and accumulation in bacteria; Cooksey DA; An unusual mechanism of metal resistance is found in certain plant pathogenic strains of Pseudomonas syringae