RERJ1, a jasmonic acid-responsive gene from rice, encodes a basic helix-loop-helix protein

Differential screening of a cDNA library constructed using poly(A)(+) RNA from suspension-cultured rice cells treated with jasmonic acid (JA) for 1/2h yielded a cDNA of a gene tentatively named RERJ1 that is upregulated in response to exogenous JA. Northern blot analysis indicated that the RERJ1 mRNA levels peaked at 1/2-1h after the addition of jasmonic acid and then decreased gradually. RERJ1 encodes a transcriptional regulator with a basic helix-loop-helix motif. The phenotypes of transgenic rice plants overexpressing sense or antisense RERJ1 mRNA demonstrated that RERJ1 is involved in the growth inhibition of rice shoots caused by JA. Other biological functions of RERJ1 are discussed from an evolutionary standpoint.

Crystallization and preliminary crystallographic analysis of the 2'-aminobiphenyl-2,3-diol 1,2-dioxygenase from the carbazole-degrader Pseudomonas resinovorans strain CA10

CarBaBb, the class III extradiol dioxygenase involved in carbazole degradation by Pseudomonas resinovorans CA10, was crystallized at 278 K by the hanging-drop vapour-diffusion method using PEG MME 550 as a precipitant. The crystals had a transparent thin square-pillar shape and belonged to space group P2(1)2(1)2, with unit-cell parameters a = 122.8, b = 144.6, c = 49.2 A, alpha = beta = gamma = 90 degrees . The crystals diffracted to a maximum resolution of 1.9 A and gave a data set with an overall R(merge) of 5.7% and a completeness of 98.6%. The V(M) value was 2.52 A(3) Da(-1), which indicated a solvent content of 51.2%.

Large plasmid pCAR2 and class II transposon Tn4676 are functional mobile genetic elements to distribute the carbazole/dioxin-degradative car gene cluster in different bacteria

The carbazole-catabolic plasmid pCAR1 isolated from Pseudomonas resinovorans strain CA10 was sequenced in its entirety; and it was found that pCAR1 carries the class II transposon Tn4676 containing carbazole-degradative genes. In this study, a new plasmid designated pCAR2 was isolated from P. putida strain HS01 that was a transconjugant from mating between the carbazole-degrader Pseudomonas sp. strain K23 and P. putida strain DS1. Southern hybridization and nucleotide sequence analysis of pCAR1 and pCAR2 revealed that the whole backbone structure was very similar in each. Plasmid pCAR2 was self-transmissible, because it was transferred from strain HS01 to P. fluorescens strain IAM12022 at the frequency of 2 x 10(-7) per recipient cell. After the serial transfer of strain HS01 on rich medium, we detected the transposition of Tn4676 from pCAR2 to the HS01 chromosome. The chromosome-located copy of Tn4676 was flanked by a 6-bp target duplication, 5'-AACATC-3'. These results experimentally demonstrated the transferability of pCAR2 and the functionality of Tn4676 on pCAR2. It was clearly shown that plasmid pCAR2 and transposon Tn4676 are active mobile genetic elements that can mediate the horizontal transfer of genes for the catabolism of carbazole.

Genetic characterization of the dibenzofuran-degrading Actinobacteria carrying thedbfA1A2gene homologues isolated from activated sludge

Thirteen dibenzofuran (DF)-utilizing bacteria carrying the DF terminal dioxygenase genes homologous to those of Terrabacter sp. strain DBF63 (dbfA1A2) were newly isolated from activated sludge samples. The amplified ribosomal DNA restriction analysis and the hybridization analyses showed that these strains were grouped into five genetically different types of bacteria. The sequence analyses of the 16S rRNA genes and the dbfA1A2 homologues from these five selected isolates revealed that the isolates belonged to the genus Rhodococcus, Terrabacter or Janibacter and that they shared 99-100% conserved dbfA1A2 homologues. We investigated the genetic organizations flanking the dbfA1A2 homologues and showed that the minimal conserved DNA region present in all five selected isolates consisted of an approximately 9.0-kb region and that their outer regions became abruptly non-homologous. Among them, Rhodococcus sp. strain DFA3 possessed not only the 9.0-kb region but also the 6.2-kb region containing dbfA1A2 homologues. Sequencing of their border regions suggested that some genetic rearrangement might have occurred with insertion sequence-like elements. Also, within their conserved regions, some insertions or deletions were observed.

Transcriptional regulation of the ant operon, encoding two-component anthranilate 1,2-dioxygenase, on the carbazole-degradative plasmid pCAR1 of Pseudomonas resinovorans strain CA10

The carbazole-degradative plasmid pCAR1 of Pseudomonas resinovorans strain CA10 has two gene clusters, carAaAaBaBbCAcAdDFE and antABC, which are involved in the conversions of carbazole to anthranilate and anthranilate to catechol, respectively. We proved that the antABC gene cluster, encoding two-component anthranilate 1,2-dioxygenase, constitutes a single transcriptional unit through Northern hybridization and reverse transcription-PCR (RT-PCR) analyses. The transcription start point of antA was mapped at 53 bp upstream point of its translation start point, and the -10 and -35 boxes were homologous to conserved sigma70 recognition sequence. Hence the promoter of the ant operon was designated Pant. 5' Deletion analyses using luciferase as a reporter showed that the region up to at least 70 bp from the transcription start point of antA was necessary for the activation of Pant. Luciferase expression from Pant was induced by anthranilate itself, but not by catechol. Two probable AraC/XylS-type regulatory genes found on pCAR1, open reading frame 22 (ORF22) and ORF23, are tandemly located 3.2 kb upstream of the antA gene. We revealed that the product of ORF23, designated AntR, is indispensable for the stimulation of Pant in Pseudomonas putida cells. Northern hybridization and RT-PCR analyses revealed that another copy of Pant, which is thought to be translocated about 2.1 kb upstream of the carAa gene as a consequence of the transposition of ISPre1, actually drives transcription of the carAa gene in the presence of anthranilate, indicating that both ant and car operons are simultaneously regulated by AntR.

Characterization of the upper pathway genes for fluorene metabolism in Terrabacter sp. strain DBF63

Genes involved in the degradation of fluorene to phthalate were characterized in the fluorene degrader Terrabacter sp. strain DBF63. The initial attack on both fluorene and 9-fluorenone was catalyzed by DbfA to yield 9-fluorenol and 1,1a-dihydroxy-1-hydro-9-fluorenone, respectively. The FlnB protein exhibited activities against both 9-fluorenol and 1,1a-dihydroxy-1-hydro-9-fluorenone to produce 9-fluorenone and 2'-carboxy-2,3-dihydroxybiphenyl, respectively. FlnD is a heteromeric protein encoded by flnD1 and ORF16, being a member of the class III two-subunit extradiol dioxygenase. FlnE was identified as a serine hydrolase for the meta-cleavage products that yield phthalate.

Achievement of ultralow emittance beam in the accelerator test facility damping ring

For high luminosity in electron-positron linear colliders, it is essential to generate low vertical emittance beams. We report on the smallest vertical emittance achieved in single-bunch-mode operation of the Accelerator Test Facility, which satisfies the requirement of the x-band linear collider. The emittances were measured with a laser-wire beam-profile monitor installed in the damping ring. The bunch length and the momentum spread of the beam were also recorded under the same conditions. The smallest vertical rms emittance measured at low intensity is 4 pm at a beam energy of 1.3 GeV, which corresponds to the normalized emittance of 1.0x1.0(-8) m. It increases by a factor of 1.5 for a bunch intensity of 10(10) electrons. The measured data agreed to the calculation of intrabeam scattering within much better than a factor of 2.

Staple line coverage with absorbable mesh after thoracoscopic bullectomy for spontaneous pneumothorax

BACKGROUND

Thoracoscopic simple bullectomy for primary spontaneous pneumothorax (PSP) has a relatively high postoperative recurrence rate and sometimes results in postoperative air leakage. One of the reasons for postoperative recurrence is the regrowth of bullae around the staple line. Therefore, reinforcement of the visceral pleura around the staple line is a reasonable way to prevent postoperative air leaks and recurrence. This study was done to determine the efficacy in preventing postoperative air leak and recurrent pneumothorax of widely covering the staple line with absorbable mesh after thoracoscopic bullectomy.

METHODS

Wide coverage of the staple line with absorbable mesh was performed on 114 patients with PSP. These patients were retrospectively compared with 126 patients who underwent thoracoscopic simple bullectomy alone.

RESULTS

The postoperative duration of chest drainage in the coverage group (mean, 1 day; range, 0-5) was significantly shorter than that in the simple bullectomy group (mean, 3 days; range 0-20). A prolonged air leak (>7 days) occurred in six patients in the simple bullectomy group, but there were no such leaks in the coverage group. Recurrent pneumothorax occurred in three patients (2.6%) in the coverage group and 12 patients (9.5%) in the simple bullectomy group.

CONCLUSION

Wide coverage of the staple line with absorbable mesh is effective in preventing postoperative air leak and in decreasing the recurrence rates of PSP.

Molecular cloning and characterization of a cDNA encoding ent-cassa-12,15-diene synthase, a putative diterpenoid phytoalexin biosynthetic enzyme, from suspension-cultured rice cells treated with a chitin elicitor

We have isolated and characterized a cDNA encoding a novel diterpene cyclase, OsDTC1, from suspension-cultured rice cells treated with a chitin elicitor. OsDTC1 functions as ent-cassa-12,15-diene synthase, which is considered to play a key role in the biosynthesis of (-)-phytocassanes recently isolated as rice diterpenoid phytoalexins. The expression of OsDTC1 mRNA was also confirmed in ultraviolet (UV)-irradiated rice leaves. In addition, we identified ent-cassa-12,15-diene, a putative diterpene hydrocarbon precursor of (-)-phytocassanes, as an endogenous compound in the chitin-elicited suspension-cultured rice cells and the UV-irradiated rice leaves. The OsDTC1 cDNA isolated here will be a useful tool to investigate the regulatory mechanisms of the biosynthesis of (-)-phytocassanes in rice.

Isolation and characterization of an alkaliphilic bacterium utilizing pyrene as a carbon source

Alkaliphilic Mycobacterium sp. strain MHP-1, which can grow on pyrene as a sole carbon and energy source, was isolated from a soil sample. At the optimum pH for growth (pH 9), about 50% of pyrene (final concentration at 0.1% [w/v]) was degraded during 7 d of incubation, and 4,5-phenanthrenedioic acid, 4-phenanthroic acid and phthalic acid were identified as metabolic intermediates. Strain MHP-1 was found to possess aromatic-ring dioxygenase genes, which are highly homologous to the known nidAB genes from pyrene-degrading mycobacteria.

Divergence of mobile genetic elements involved in the distribution of xenobiotic-catabolic capacity

Bacteria adapt rapidly to environmental stimuli, such as exposure to xenobiotics. Mobile genetic elements (MGEs) play a major role in such bacterial adaptation, via the dispersal of catabolic capacity; and, in fact, genes that encode the degradation enzymes for xenobiotics are often located on MGEs. The list of reported catabolic MGEs keeps growing as researchers continue to isolate and characterize xenobiotic degraders and the corresponding catabolic genes. Major catabolic MGEs include (conjugative) plasmids, transposons, and conjugative transposons. Catabolic transposons can be divided into class I elements (composite transposons) and class II elements (Tn 3 family transposons). This review includes a comprehensive list of naturally occurring discrete catabolic MGEs, together with a brief description for each. While MGEs are often rather large, genome-wide or large-scale sequence analyses have provided useful information on the whole genetic structure of MGEs, with clues to their function (transfer, maintenance, catabolism, etc.) and behavior in a complex natural environment. This review also gives an insight into MGE functions, based on the complete sequencing of several catabolic plasmids and two Pseudomonas genomes.

Polarimetry of short-pulse gamma rays produced through inverse Compton scattering of circularly polarized laser beams

We have developed a polarimetry of ultrashort pulse gamma rays based on the fact that gamma rays penetrating in the forward direction through a magnetized iron carry information on the helicity of the original gamma rays. Polarized, short-pulse gamma rays of (1.1+/-0.2)x10(6)/bunch with a time duration of 31 ps and a maximum energy of 55.9 MeV were produced via Compton scattering of a circularly polarized laser beam of 532 nm off an electron beam of 1.28 GeV. The first demonstration of asymmetry measurements of short-pulse gamma rays was conducted using longitudinally magnetized iron of 15 cm length. It is found that the gamma-ray intensity is in good agreement with the simulated value of 1.0x10(6). Varying the degree of laser polarization, the asymmetry for 100% laser polarization was derived to be (1.29+/-0.12)%, which is also consistent with the expected value of 1.3%.

Carbazole/dioxin-degrading car gene cluster is located on the chromosome of Pseudomonas stutzeri strain OM1 in a form different from the simple transposition of Tn4676

The carbazole-degrading (car) operon on the chromosome of Pseudomonas stutzeri strain OM1 showed > 99% identity to that in the 72.8 kb catabolic transposon, Tn4676, on plasmid pCAR1. Southern hybridization using probes prepared from the pCAR1 sequence and sequencing analyses showed that the OM1 chromosome contained the 55 kb DNA region, almost all of which was a part of Tn4676, flanked by two copies of novel insertion sequence, ISPst3, and included the car gene.

Characterization and identification of genes essential for dimethyl sulfide utilization in Pseudomonas putida strain DS1

Microbial dimethyl sulfide (DMS) conversion is thought to be involved in the global sulfur cycle. We isolated Pseudomonas putida strain DS1 from soil as a bacterium utilizing DMS as a sole sulfur source, and tried to elucidate the DMS conversion mechanism of strain DS1 at biochemical and genetic level. Strain DS1 oxidized DMS to dimethyl sulfone (DMSO(2)) via dimethyl sulfoxide, whereas the oxidation was repressed in the presence of sulfate, suggesting that a sulfate starvation response is involved in DMS utilization by strain DS1. Two of the five DMS-utilization-defective mutants isolated by transposon 5 (Tn 5) mutagenesis had a Tn 5 insertion in the ssuEADCBF operon, which has been reported to encode a two-component monooxygenase system (SsuED), an ABC-type transporter (SsuABC), and a small protein (SsuF), and also to play a key role in utilization of sulfonates and sulfate esters in another bacterium, P. putida strain S-313. Disruption of ssuD and SsuD enzymatic activity demonstrated that methanesulfonate is a metabolic intermediate of DMS and desulfonated by SsuD. Disruption of ssuC or ssuF also led to a DMS-utilization-defective phenotype. Another two mutants had a defect in a gene homologous to pa2354 from P. aeruginosa PAO1, which encodes a putative transcriptional regulator, while the remaining mutant had a defect in cysM encoding O-acetylserine (thiol)-lyase B.

Marinobacterium sp. strain DMS-S1 uses dimethyl sulphide as a sulphur source after light-dependent transformation by excreted flavins

Marinobacterium sp. strain DMS-S1 is a unique marine bacterium that can use dimethyl sulphide (DMS) as a sulphur source only in the presence of light. High-performance liquid chromatography (HPLC) analyses of the culture supernatant revealed that excreted factors, which could transform DMS to dimethyl sulphoxide (DMSO) under light, are FAD and riboflavin. In addition, FAD appeared to catalyse the photolysis of DMS to not only DMSO but also methanesulphonate (MSA), formate, formaldehyde and sulphate. As strain DMS-S1 can use sulphate and MSA as a sole sulphur source independently of light, the excretion of flavins appeared to support the growth on DMS under light. Furthermore, three out of 12 marine bacteria from IAM culture collection were found to be able to grow on DMS with the aid of photolysis by the flavins excreted. This is the first report that bacteria can use light to assimilate oceanic organic sulphur compounds outside the cells by excreting flavins as photosensitizers.

Rhizoremediation of dioxin-like compounds by a recombinant Rhizobium tropici strain expressing carbazole 1,9a-dioxygenase constitutively

A recombinant Rhizobium strain, PBK3-IS, that constitutively expressed the oxygenase component of carbazole 1,9a-dioxygenase from Sphingomonas sp. strain KA1, was constructed. In the water-cultured siratro rhizospheres inoculated with strain PBK3-IS, 48% of the dibenzofuran was removed within 3 days (initial substrate, 25 microg). Similar results were obtained in soil-cultured siratro rhizospheres using sterile vermiculite. When non-sterile field soils were used instead of sterile vermiculite, the inoculated recombinant strain could grow on the siratro root in all soils tested, except for wet paddy field.

Crystal structure of a histidine-tagged serine hydrolase involved in the carbazole degradation (CarC enzyme)

2-Hydroxy-6-oxo-6-(2(')-aminophenyl)-hexa-2,4-dienoate hydrolases (CarC enzymes) from two carbazole-degrading bacteria were purified using recombinant Escherichia coli strains with the histidine (His)-tagged purification system. The His-tagged CarC (ht-CarC) enzymes from Pseudomonas resinovorans strain CA10 (ht-CarC(CA10)) and Janthinobacterium sp. strain J3 (ht-CarC(J3)) exhibited hydrolase activity toward 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate as the purified native CarC(CA10) did. ht-CarC(J3) was crystallized in the space group I422 with cell dimensions of a=b=130.3A, c=84.5A in the hexagonal setting, and the crystal structure of ht-CarC(J3) was determined at 1.86A resolution. The final refined model of ht-CarC(J3) yields an R-factor of 21.6%, although the electron-density corresponding to Ile146 to Asn155 was ambiguous in the final model. We compared the known structures of BphD from Rhodococcus sp. strain RHA1 and CumD from Pseudomonas fluorescens strain IP01. The backbone conformation of ht-CarC(J3) was better superimposed with CumD than with BphD(RHA1). The side-chain directions of Arg185 and Trp262 residues in the substrate binding pockets of these enzymes were different among these proteins, suggesting that these residues may take a conformational change during the catalytic cycles.

A CysB-regulated and sigma54-dependent regulator, SfnR, is essential for dimethyl sulfone metabolism of Pseudomonas putida strain DS1

Pseudomonas putida strain DS1 utilizes dimethyl sulfide (DMS) as a sulfur source, and desulfurizes it via dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO(2)) and methanesulfonate (MSA). Its Tn5 mutant, Dfi74J, no longer utilized DMS, DMSO and DMSO(2), but could oxidize DMS to DMSO(2), suggesting that the conversion of DMSO(2) to MSA was interrupted in the mutant. Sequencing of the Tn5 flanking region of Dfi74J demonstrated that a gene, sfnR (designated for dimethyl sulfone utilization), encoding a transcriptional regulator containing an ATP-dependent sigma(54)-association domain and a DNA-binding domain, was disrupted. sfnR is part of an operon with two other genes, sfnE and sfnC, located immediately upstream of sfnR and in the same orientation. The genes encode NADH-dependent FMN reductase (SfnE) and FMNH(2)-dependent monooxygenase (SfnC). Complementation of Dfi74J with an sfnR-expressing plasmid led to restoration of its growth on DMS, DMSO and DMSO(2). An rpoN-defective mutant of strain DS1, which lacks the sigma(54) factor, grew on MSA, but not on DMS, DMSO and DMSO(2), indicating that SfnR controls expression of gene(s) involved in DMSO(2) metabolism by interaction with sigma(54)-RNA polymerase. Northern hybridization and a reporter gene assay with an sfn-lacZ transcriptional fusion elucidated that expression of the sfnECR operon was induced under sulfate limitation and was dependent on a LysR-type transcriptional regulator, CysB. This is believed to be the first report that a sigma(54)-dependent transcriptional regulator induced under sulfate limitation is involved in sulfur assimilation.

Phthalate catabolic gene cluster is linked to the angular dioxygenase gene in Terrabacter sp. strain DBF63

Phthalate is a metabolic intermediate of the pathway of fluorene (FN) degradation via angular dioxygenation. A gene cluster responsible for the conversion of phthalate to protocatechuate was cloned from the dibenzofuran (DF)- and FN-degrading bacterium Terrabacter sp. strain DBF63 and sequenced. The genes encoding seven catabolic enzymes, oxygenase large subunit of phthalate 3,4-dioxygenase (phtA1), oxygenase small subunit of phthalate 3,4-dioxygenase (phtA2), cis-3,4-dihydroxy-3,4-dihydrophthalate dehydrogenase (phtB), [3Fe-4S] or [4Fe-4S] type of ferredoxin (phtA3), ferredoxin reductase (phtA4), 3,4-dihydroxyphthalate decarboxylase (phtC) and putative regulatory protein (phtR), were found in the upstream region of the angular dioxygenase gene (dbfA1A2), encoded in this order. Escherichia coli carrying phtA1A2BA3A4 genes converted phthalate to 3,4-dihydroxyphthalate, and the 3,4-dihydroxyphthalate decarboxylase activity by E. coli cells carrying phtC was finally detected with the introduction of a Shine-Dalgarno sequence in the upstream region of its initiation codon. Homology analysis on the upstream region of the pht gene cluster revealed that there was an insertion sequence (IS) (ISTesp2; ORF14 and its flanking region), part of which was almost 100% identical to the orf1 and its flanking region adjacent to the extradiol dioxygenase gene ( bphC1) involved in the DF degradation of Terrabacter sp. strain DPO360 [Schmid et al. (1997) J Bacteriol 179:53-62]. This suggests that ISTesp2 plays a role in the metabolism of aromatic compounds in Terrabacter sp. strains DBF63 and DPO360.

Identification of three novel salicylate 1-hydroxylases involved in the phenanthrene degradation of Sphingobium sp. strain P2

Five sets of large and small subunits of terminal oxygenase (ahdA1[a-e] and ahdA2[a-e]) and a single gene set encoding ferredoxin (ahdA3) and ferredoxin reductase (ahdA4) were found to be scattered through 15.8- and 14-kb DNA fragments of phenanthrene-degrading Sphingobium sp. strain P2. RT-PCR analysis indicated the inducible and specific expression of ahdA3, ahdA4, and three sets of genes for terminal oxygenase (ahdA1[c-e] and ahdA2[c-e]) in this strain grown on phenanthrene. The biotransformation experiments with resting cells of Escherichia coli JM109 harboring recombinant ahd genes revealed that AhdA2cA1c, AhdA1dA2d, and AhdA1eA2e can all function as a salicylate 1-hydroxylase which converts salicylate, a metabolic intermediate of phenanthrene, to catechol in cooperation with the electron transport proteins AhdA3A4. The first two oxygenases exhibited a broad range of substrate specificities such that they also catalyzed the hydroxylation of methyl- and chloro-substituted salicylates to produce their corresponding substituted catechols.

Complete nucleotide sequence of carbazole/dioxin-degrading plasmid pCAR1 in Pseudomonas resinovorans strain CA10 indicates its mosaicity and the presence of large catabolic transposon Tn4676

The car and ant operons originally isolated from Pseudomonas resinovorans strain CA10 contain the genes encoding the carbazole/dioxin-degrading enzymes and anthranilate 1,2-dioxygenase, respectively, and are located on the plasmid pCAR1. The entire nucleotide sequence of pCAR1 was determined to elucidate the mechanism by which the car operon may have been assembled and distributed in nature. pCAR1 is a 199,035-bp circular plasmid, and carries 190 open reading frames. Although the incompatibility group of pCAR1 is unclear, its potential origin for replication, OriP, and Rep and Par proteins appeared to be closely related to those of plasmid pL6.5 isolated from Pseudomonas fluorescens. The potential tellurite-resistance klaABC genes identified in the neighboring region of repA gene were also related to those in IncP plasmid originally identified from pseudomonads. On the other hand, we found genes encoding proteins that showed low but significant homology (20-45% identity) with Trh and Tra proteins from Enterobacteriaceae, which are potentially involved in conjugative transfer of plasmids or genomic island, suggesting that pCAR1 is also a conjugative plasmid. In pCAR1, we found tnpAcCST genes that encoded the proteins showing >70% length-wise identities with those are encoded by the toluene/xylene-degrading transposon Tn4651 of TOL plasmid pWW0. Both car and ant degradative operons were found within a 72.8-kb Tn4676 sequence defined by flanking tnpAcC and tnpST genes and bordered by a 46-bp inverted repeat (IR). Within Tn4676 and its flanking region, we found the remnants of numerous mobile genetic elements, such as the duplicated transposase genes that are highly homologous to tnpR of Tn4653 and the multiple candidates of IRs for Tn4676 and Tn4653-like element. We also found distinct regions with high and low G+C contents within Tn4676, which contain an ant operon and car operon, respectively. These results suggested that multiple step assembly could have taken place before the current structure of Tn4676 had been captured.

Genes involved in the synthesis of the exopolysaccharide methanolan by the obligate methylotroph Methylobacillus sp strain 12S

Methylobacillus sp. strain 12S produces an exopolysaccharide (EPS), methanolan, composed of glucose, mannose and galactose. Twenty-four ORFs flanking a Tn5 insertion site in an EPS-deficient mutant were identified, and 21 genes (epsCBAKLDEFGHIJMNOPQRSTU) were predicted to participate in methanolan synthesis on the basis of the features of the primary sequence. Gene disruption analyses revealed that epsABCEFGIJNOP and epsR are required for methanolan synthesis, whereas epsKD and epsH are not essential. EpsFG and EpsE showed homology with Wzc (chain length regulator) and Wza (export protein) of group 1 capsule-producing Escherichia coli, suggesting that methanolan was synthesized via a Wzy-like biosynthesis system. This possibility was supported by the fact that the putative hydropathy profiles of EpsH and EpsM were similar to those of Wzx and Wzy, which are also involved in the flipping of the repeating unit in the cytoplasmic membrane and the polymerization of the capsule in the Wzy-dependent system. EpsBJNOP and EpsR are probably glycosyltransferases involved in the synthesis of the repeating unit onto the lipid carrier. In particular, EpsB appeared to catalyse the initial transfer of the glucose moiety. On the basis of their predicted location in the cells, it is proposed that EpsI and EpsL are involved in methanolan export to the cell surface. E. coli strains expressing EpsQ, EpsS and EpsT showed enhanced activities of GDP-mannose pyrophosphorylase, UDP-galactose 4-epimerase and UDP-glucose pyrophosphorylase, respectively, revealing that they were responsible for the production of the activated compositional sugars of methanolan. EpsU contains a conserved a lytic transglycosylase motif, indicating that it could participate in the degradation of polysaccharides. EpsA and EpsK, which have conserved DNA-binding and cAMP-binding motifs, respectively, were deduced to be transcriptional regulators. In particular, EpsA seems to positively regulate the transcription of methanolan synthesis genes, since the constitutive expression of epsA in strain 12S increased the EPS production. Interestingly, EpsD showed homology with peptidyl prolyl cis-trans isomerases that catalyse the folding of proteins following translocation across the cytoplasmic membrane.