RecET Direct Cloning of Polysaccharide Gene Cluster from Gram-Negative Bacteria

Author(s):  
Zhongrui Ma ◽  
Peng George Wang
Author(s):  
Miao Wan ◽  
Xun Gao ◽  
Luchao Lv ◽  
Zhongpeng Cai ◽  
Jian-Hua Liu

Tigecycline and colistin are considered 20 as the final options for the treatment of infections caused by multidrug-resistant (MDR) gram-negative bacteria, especially carbapenem-resistant Enterobacteriaceae (1).…


2002 ◽  
Vol 70 (6) ◽  
pp. 3271-3276 ◽  
Author(s):  
Elvia Pacinelli ◽  
Lei Wang ◽  
Peter R. Reeves

ABSTRACT O antigen is part of the lipopolysaccharide present in the outer membrane of gram-negative bacteria and is highly polymorphic. In this study, we obtained sequences of the O-antigen gene clusters for the Yersinia pseudotuberculosis antigens IA, IIA, and IVB. We propose that the IIA gene cluster was derived from the IVB cluster, one of the very few cases in which a parent gene cluster is identified, and that the IA gene cluster could be a hybrid of the IVB and IB gene clusters. All three O antigens contain 6-deoxy-d-mannoheptose, and we identified six genes for the biosynthetic pathway for the precursor of this sugar, GDP-6-deoxy-d-mannoheptose.


2019 ◽  
Author(s):  
Taisei Yamamoto ◽  
Yaxuan Liu ◽  
Nozomi Kohaya ◽  
Yoshie Hasegawa ◽  
Peter C.K. Lau ◽  
...  

AbstractBesides an industrial pollutant, 2,4-dinitrophenol (DNP) has been used illegally as a weight loss drug that had claimed human lives. Little is known about the metabolism of DNP, particularly among Gram-negative bacteria. In this study, two non-contiguous genetic loci of Paraburkholderia (formerly Burkholderia) sp. strain KU-46 genome were identified and four key initial genes (dnpA, dnpB, and dnpC1C2) were characterized to provide molecular and biochemical evidence for the degradation of DNP via the formation of 4-nitrophenol (NP), a pathway that is unique among DNP utilizing bacteria. Reverse transcription PCR analysis indicated that the dnpA gene encoding the initial hydride transferase (28 kDa), and the dnpB gene encoding a nitrite-eliminating enzyme (33 kDa), are inducible by DNP and the two genes are organized in an operon. Purified DnpA and DnpB from overexpression clones in Escherichia coli effected the transformation of DNP to NP via the formation of hydride-Meisenheimer complex of DNP. The function of DnpB appears new since all homologs of DnpB sequences in the protein database are annotated as putative nitrate ABC transporter substrate-binding proteins. The gene cluster responsible for the degradation of DNP after NP formation was designated dnpC1C2DXFER. DnpC1 and DnpC2 were functionally characterized as the respective FAD reductase and oxygenase components of the two-component NP monooxygenase. Both NP and 4-nitrocatechol were shown to be substrates, producing hydroquinone and hydroxyquinol, respectively. Elucidation of the hqdA1A2BCD gene cluster allows the delineation of the final degradation pathway of hydroquinone to ß-ketoadipate prior to its entry to the tricarboxylic acid cycle.ImportanceThis study fills a gap in our knowledge and understanding of the genetic basis and biochemical pathway for the degradation of 2,4-dinitrophenol (DNP) in Gram-negative bacteria, represented by the prototypical Paraburkholderia sp. strain KU-46 that metabolizes DNP through the formation of 4-nitrophenol, a pathway unseen by other DNP utilizers. The newly cloned genes could serve as DNA probes in biomonitoring as well as finding application in new biocatalyst development to access green chemicals. By and large, knowledge of the diverse strategies used by microorganisms to degrade DNP will contribute to the development of bioremediation solutions since DNP is an industrial pollutant used widely in the chemical industry for the synthesis of pesticides, insecticides, sulfur dyes, wood preservatives, and explosives, etc. (119 words)


1998 ◽  
Vol 180 (4) ◽  
pp. 1002-1007 ◽  
Author(s):  
Heather Curd ◽  
Dan Liu ◽  
Peter R. Reeves

ABSTRACT The O antigen is an important cell wall antigen of gram-negative bacteria, and the genes responsible for its biosynthesis are located in a gene cluster. We have cloned and sequenced the DNA segment unique to the O-antigen gene cluster of Salmonella enterica group D3. This segment includes a novel O-antigen polymerase gene (wzy D3). The polymerase gives α(1→6) linkages but has no detectable sequence similarity to that of group D2, which confers the same linkage. We find the remnant of a D3-likewzy gene in the O-antigen gene clusters of groups D1 and B and suggest that this is the original wzy gene of these O-antigen gene clusters.


2021 ◽  
Author(s):  
Shotaro Maehana ◽  
Ryotaro Eda ◽  
Nagi Niida ◽  
Aki Hirabayashi ◽  
Kouji Sakai ◽  
...  

Tigecycline exhibits promising activity against multidrug-resistant gram-negative bacteria (MDR-GNB). However, mobile tigecycline resistance genes, such as tmexCD-toprJ encoding RND efflux pumps, have emerged. Here, we identified a novel tmexC3D2-toprJ3 gene cluster in tigecycline- and carbapenem-nonsusceptible Pseudomonas alcaligenes isolates from hospital sewage in Japan in 2020. tmexC3D2-toprJ3 and two copies of blaIMP-1 were located on the chromosome. This suggests that diverse tmexCD-toprJ-like genes have spread among MDR-GNB worldwide and further epidemiological genomic studies are needed.


Author(s):  
Roger C. Wagner

Bacteria exhibit the ability to adhere to the apical surfaces of intestinal mucosal cells. These attachments either precede invasion of the intestinal wall by the bacteria with accompanying inflammation and degeneration of the mucosa or represent permanent anchoring sites where the bacteria never totally penetrate the mucosal cells.Endemic gram negative bacteria were found attached to the surface of mucosal cells lining the walls of crypts in the rat colon. The bacteria did not intrude deeper than 0.5 urn into the mucosal cells and no degenerative alterations were detectable in the mucosal lining.


Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.


Author(s):  
Xie Nianming ◽  
Ding Shaoqing ◽  
Wang Luping ◽  
Yuan Zenglin ◽  
Zhan Guolai ◽  
...  

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.


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