scholarly journals The tet39 Determinant and the msrE-mphE Genes in Acinetobacter Plasmids Are Each Part of Discrete Modules Flanked by Inversely Oriented pdif (XerC-XerD) Sites

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Grace A. Blackwell ◽  
Ruth M. Hall

ABSTRACT The tet39 tetracycline resistance determinant and the macrolide resistance genes msrE and mphE were found in an 18.2-kb plasmid, pS30-1, recovered from a global clone 2 (GC2) Acinetobacter baumannii isolate from Singapore, that conferred resistance to tetracycline and erythromycin. pS30-1 also contains mobA and mobC genes encoding MOBQ family proteins, but attempts to mobilize pS30-1 utilizing a coresident conjugative repAci6 plasmid were unsuccessful. Eight pdif sites, consisting of inversely oriented binding sites for the XerC and XerD recombinases separated by 6 bp, were detected in pS30-1. The tet39 determinant and the msrE-mphE gene pair are each surrounded by two pdif sites in inverse orientation. Identical regions in different contexts and many previously unnoticed pdif sites were found in a number of different plasmids in GenBank, showing that the tet39 and msrE-mphE dif modules are mobile. A putative toxin/antitoxin system, a gene encoding a serine recombinase, and open reading frames of unknown function were also part of dif modules in pS30-1. In general, modules with internal XerC or XerD sites alternate. Two copies of ISAjo2-1 (94% identical to ISAjo2) in pS30-1 were inserted 5 bp from a XerC site, and this appears to be the preferred insertion site for this insertion sequence (IS) group. Apparently, Acinetobacter plasmids exploit the Acinetobacter XerC-XerD recombinases to mobilize DNA units containing resistance and other genes, via an uncharacterized mechanism. The tet39 and msrE-mphE dif modules add to the oxa24 module and the oxa58 module redefined here, bringing the total of resistance gene-containing dif modules in Acinetobacter plasmids to four.

2007 ◽  
Vol 73 (8) ◽  
pp. 2491-2497 ◽  
Author(s):  
Stephan Bathe ◽  
Paul R. Norris

ABSTRACT Genes of Sulfolobus metallicus that appeared to be upregulated in relation to growth on either ferrous iron or sulfur were identified using subtractive hybridization of cDNAs. The genes upregulated during growth on ferrous iron were found in a cluster, and most were predicted to encode membrane proteins. Quantitative reverse transcription-PCR of cDNA showed upregulation of most of these genes during growth on ferrous iron and pyrite compared to results during growth on sulfur. The highest expression levels observed included those for genes encoding proteins with similarities to cytochrome c oxidase subunits and a CbsA-like cytochrome. The genes identified here that may be involved in oxidation of ferrous iron by S. metallicus are termed fox genes. Of three available genomes of Sulfolobus species (S. tokodaii, S. acidocaldarius, and S. solfataricus), only that of S. tokodaii has a cluster of highly similar open reading frames, and only S. tokodaii of these three species was also able to oxidize ferrous iron. A gene encoding sulfur oxygenase-reductase was identified as the source of the dominant transcript in sulfur-grown cells of S. metallicus, with the predicted protein showing high identities to the previously described examples from S. tokodaii and species of Acidianus.


2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Helena Turano ◽  
Fernando Gomes ◽  
Gesiele A. Barros-Carvalho ◽  
Ralf Lopes ◽  
Louise Cerdeira ◽  
...  

ABSTRACT A novel transposon belonging to the Tn3-like family was identified on the chromosome of a commensal strain of Pseudomonas aeruginosa sequence type 2343 (ET02). Tn6350 is 7,367 bp long and harbors eight open reading frames (ORFs), an ATPase (IS481 family), a transposase (DDE catalytic type), a Tn3 resolvase, three hypothetical proteins, and genes encoding the new pyocin S8 with its immunity protein. We show that pyocin S8 displays activity against carbapenemase-producing P. aeruginosa, including IMP-1, SPM-1, VIM-1, GES-5, and KPC-2 producers.


2020 ◽  
Vol 9 (22) ◽  
Author(s):  
Anastasia V. Popova ◽  
Mikhail M. Shneider ◽  
Yulia V. Mikhailova ◽  
Andrey A. Shelenkov ◽  
Dmitry A. Shagin ◽  
...  

ABSTRACT Acinetobacter myovirus BS46 was isolated from sewage by J. S. Soothill in 1991. We have sequenced the genome of BS46 and found it to be almost unique. BS46 contains double-stranded DNA with a genome size of 94,068 bp and 176 predicted open reading frames. The gene encoding the tailspike that presumably possesses depolymerase activity toward the capsular polysaccharides of the bacterial host was identified.


2013 ◽  
Vol 79 (8) ◽  
pp. 2828-2832 ◽  
Author(s):  
Lynn El Haddad ◽  
Sylvain Moineau

ABSTRACTA new siphophage (LH1) was isolated from raw milk using aStaphylococcus aureusST352 host. Its genome (46,048 bp, 57 open reading frames) includes the two genes encoding Panton-Valentine leukocidin (PVL), a virulence factor usually harbored byS. aureusprophages. Nine structural proteins were identified, including a tail protein generated through a +1 frameshift. A phage lytic mutant was isolated, and its analysis revealed the deletion of genes coding for the PVL and an integrase. The deletion likely occurred through recombination between direct repeats.


2015 ◽  
Vol 81 (10) ◽  
pp. 3336-3348 ◽  
Author(s):  
Diana Gutiérrez ◽  
Dieter Vandenheuvel ◽  
Beatriz Martínez ◽  
Ana Rodríguez ◽  
Rob Lavigne ◽  
...  

ABSTRACTPhage therapy is a promising option for fighting against staphylococcal infections. Two lytic phages, vB_SauM_phiIPLA-RODI (phiIPLA-RODI) and vB_SepM_phiIPLA-C1C (phiIPLA-C1C), belonging to theMyoviridaefamily and exhibiting wide host ranges, were characterized in this study. The complete genome sequences comprised 142,348 bp and 140,961 bp and contained 213 and 203 open reading frames, respectively. The gene organization was typical ofSpounavirinaemembers, with long direct terminal repeats (LTRs), genes grouped into modules not clearly separated from each other, and several group I introns. In addition, four genes encoding tRNAs were identified in phiIPLA-RODI. Comparative DNA sequence analysis showed high similarities with two phages, GH15 and 676Z, belonging to theTwort-like virusgenus (nucleotide identities of >84%); for phiIPLA-C1C, a high similarity with phage phiIBB-SEP1 was observed (identity of 80%). Challenge assays of phages phiIPLA-RODI and phiIPLA-C1C against planktonic staphylococcal cells confirmed their lytic ability, as they were able to remove 5 log units in 8 h. Exposure of biofilms to phages phiIPLA-RODI and phiIPLA-C1C reduced the amount of adhered bacteria to about 2 log units in both monospecies and dual-species biofilms, but phiIPLA-RODI turned out to be as effective as the mixture of both phages. Moreover, the frequencies of bacteriophage-insensitive mutants (BIMs) ofStaphylococcus aureusandS. epidermidiswith resistance to phiIPLA-RODI and phiIPLA-C1C were low, at 4.05 × 10−7± 2.34 × 10−9and 1.1 × 10−7± 2.08 × 10−9, respectively. Overall, a generally reduced fitness in the absence of phages was observed for BIMs, which showed a restored phage-sensitive phenotype in a few generations. These results confirm that lytic bacteriophages can be efficient biofilm-disrupting agents, supporting their potential as antimicrobials against staphylococcal infections.


2001 ◽  
Vol 353 (2) ◽  
pp. 403-409 ◽  
Author(s):  
Marina FRANCESCHETTI ◽  
Colin HANFREY ◽  
Sonia SCARAMAGLI ◽  
Patrizia TORRIGIANI ◽  
Nello BAGNI ◽  
...  

S-Adenosyl-L-methionine decarboxylase (AdoMetDC; EC 4.1.1.50) is one of the key regulatory enzymes in the biosynthesis of polyamines. Isolation of genomic and cDNA sequences from rice and Arabidopsis had indicated that this enzyme is encoded by a small multigene family in monocot and dicot plants. Analysis of rice, maize and Arabidopsis AdoMetDC cDNA species revealed that the monocot enzyme possesses an extended C-terminus relative to dicot and human enzymes. Interestingly, we discovered that all expressed plant AdoMetDC mRNA 5´ leader sequences contain a highly conserved pair of overlapping upstream open reading frames (uORFs) that overlap by one base. The 5´ tiny uORF consists of two or three codons and the 3´ small uORF encodes 50Ő54 residues. Sequences of the small uORFs are highly conserved between monocot, dicot and gymnosperm AdoMetDC mRNA species and the C-terminus of the plant small uORFs is conserved with the C-terminus of nematode AdoMetDC uORFs; such a conserved arrangement is strongly suggestive of a translational regulatory mechanism. No introns were found in the main AdoMetDC proenzyme ORF from any of the plant genes encoding AdoMetDC, whereas introns were found in conserved positions flanking the overlapping uORFs. The absence of the furthest 3´ intron from the Arabidopsis gene encoding AdoMetDC2 suggests that this intron was lost recently. Reverse-transcriptase-mediated PCR analysis of the two Arabidopsis genes for AdoMetDC indicated that AdoMetDC1 is abundant and ubiquitous, whereas the gene for AdoMetDC2 is expressed preferentially in leaves and inflorescences. Investigation of recently released Arabidopsis genome sequences has revealed that in addition to the two genes encoding AdoMetDC isolated as part of the present work, four additional genes are present in Arabidopsis but they are probably not expressed.


2006 ◽  
Vol 50 (2) ◽  
pp. 702-708 ◽  
Author(s):  
Mónica Blanco ◽  
César B. Gutiérrez-Martin ◽  
Elías F. Rodríguez-Ferri ◽  
Marilyn C. Roberts ◽  
Jesús Navas

ABSTRACT Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia. Tetracycline is used for therapy of this disease, and A. pleuropneumoniae carrying the tet(B) gene, coding for an efflux protein that reduces the intercellular tetracycline level, has been described previously. Of the 46 tetracycline-resistant (Tcr) Spanish A. pleuropneumoniae isolates used in this study, 32 (70%) carried the tet(B) gene, and 30 of these genes were associated with plasmids. Eight (17%) isolates carried the tet(O) gene, two (4%) isolates carried either the tet(H) or the tet(L) gene, and all these genes were associated with plasmids. This is the first description of these tet genes in A. pleuropneumoniae. The last two Tcr isolates carried none of the tet genes examined. Except for tet(O)-containing plasmids, the other 34 Tcr plasmids were transformable into an Escherichia coli recipient. Two plasmids were completely sequenced. Plasmid p11745, carrying the tet(B) gene, was 5,486 bp and included a rep gene, encoding a replication-related protein, and two open reading frames (ORFs) with homology to mobilization genes of Neisseria gonorrhoeae plasmid pSJ7.4. Plasmid p9555, carrying the tet(L) gene, was 5,672 bp and, based on its G+C content, consisted of two regions, one of putative gram-positive origin containing the tet(L) gene and the other comprising four ORFs organized in an operon-like structure with homology to mobilization genes in other plasmids of gram-negative bacteria.


2000 ◽  
Vol 182 (13) ◽  
pp. 3784-3793 ◽  
Author(s):  
Vincent J. J. Martin ◽  
William W. Mohn

ABSTRACT We have cloned and sequenced the dit gene cluster encoding enzymes of the catabolic pathway for abietane diterpenoid degradation by Pseudomonas abietaniphila BKME-9. Thedit gene cluster is located on a 16.7-kb DNA fragment containing 13 complete open reading frames (ORFs) and 1 partial ORF. The genes ditA1A2A3 encode the α and β subunits and the ferredoxin of the dioxygenase which hydroxylates 7-oxodehydroabietic acid to 7-oxo-11,12-dihydroxy-8,13-abietadien acid. The dioxygenase mutant strain BKME-941 (ditA1::Tn5) did not grow on nonaromatic abietanes, and transformed palustric and abietic acids to 7-oxodehydroabietic acid in cell suspension assays. Thus, nonaromatic abietanes are aromatized prior to further degradation. Catechol 2,3-dioxygenase activity of xylEtranscriptional fusion strains showed induction of ditA1and ditA3 by abietic, dehydroabietic, and 7-oxodehydroabietic acids, which support the growth of strain BKME-9, as well as by isopimaric and 12,14-dichlorodehydroabietic acids, which are diterpenoids that do not support the growth of strain BKME-9. In addition to the aromatic-ring-hydroxylating dioxygenase genes, thedit cluster includes ditC, encoding an extradiol ring cleavage dioxygenase, and ditR, encoding an IclR-type transcriptional regulator. Although ditR is not strictly required for the growth of strain BKME-9 on abietanes, aditR::Kmr mutation in aditA3::xylE reporter strain demonstrated that it encodes an inducer-dependent transcriptional activator of ditA3. An ORF with sequence similarity to genes encoding permeases (ditE) is linked with genes involved in abietane degradation.


2008 ◽  
Vol 190 (18) ◽  
pp. 6111-6118 ◽  
Author(s):  
P. Rousseau ◽  
C. Loot ◽  
C. Turlan ◽  
S. Nolivos ◽  
M. Chandler

ABSTRACT IS911 is a bacterial insertion sequence composed of two consecutive overlapping open reading frames (ORFs [orfA and orfB]) encoding the transposase (OrfAB) as well as a regulatory protein (OrfA). These ORFs are bordered by terminal left and right inverted repeats (IRL and IRR, respectively) with several differences in nucleotide sequence. IS911 transposition is asymmetric: each end is cleaved on one strand to generate a free 3′-OH, which is then used as the nucleophile in attacking the opposite insertion sequence (IS) end to generate a free IS circle. This will be inserted into a new target site. We show here that the ends exhibit functional differences which, in vivo, may favor the use of one compared to the other during transposition. Electromobility shift assays showed that a truncated form of the transposase [OrfAB(1-149)] exhibits higher affinity for IRR than for IRL. While there was no detectable difference in IR activities during the early steps of transposition, IRR was more efficient during the final insertion steps. We show here that the differential activities between the two IRs correlate with the different affinities of OrfAB(1-149) for the IRs during assembly of the nucleoprotein complexes leading to transposition. We conclude that the two inverted repeats are not equivalent during IS911 transposition and that this asymmetry may intervene to determine the ordered assembly of the different protein-DNA complexes involved in the reaction.


2009 ◽  
Vol 75 (10) ◽  
pp. 3106-3114 ◽  
Author(s):  
Jessica Rehdorf ◽  
Christian L. Zimmer ◽  
Uwe T. Bornscheuer

ABSTRACT While the number of available recombinant Baeyer-Villiger monooxygenases (BVMOs) has grown significantly over the last few years, there is still the demand for other BVMOs to expand the biocatalytic diversity. Most BVMOs that have been described are dedicated to convert efficiently cyclohexanone and related cyclic aliphatic ketones. To cover a broader range of substrate types and enantio- and/or regioselectivities, new BVMOs have to be discovered. The gene encoding a BVMO identified in Pseudomonas putida JD1 converting aromatic ketones (HAPMO; 4-hydroxyacetophenone monooxygenase) was amplified from genomic DNA using SiteFinding-PCR, cloned, and functionally expressed in Escherichia coli. Furthermore, four other open reading frames could be identified clustered around this HAPMO. It has been suggested that these proteins, including the HAPMO, might be involved in the degradation of 4-hydroxyacetophenone. Substrate specificity studies revealed that a large variety of other arylaliphatic ketones are also converted via Baeyer-Villiger oxidation into the corresponding esters, with preferences for para-substitutions at the aromatic ring. In addition, oxidation of aldehydes and some heteroaromatic compounds was observed. Cycloketones and open-chain ketones were not or poorly accepted, respectively. It was also found that this enzyme oxidizes aromatic ketones such as 3-phenyl-2-butanone with excellent enantioselectivity (E ≫100).


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