scholarly journals The Sandarazols are Cryptic and Structurally Unique Plasmid‐Encoded Toxins from a Rare Myxobacterium**

2021 ◽  
Vol 60 (15) ◽  
pp. 8081-8088
Author(s):  
Fabian Panter ◽  
Chantal D. Bader ◽  
Rolf Müller
Keyword(s):  
ChemInform ◽  
1989 ◽  
Vol 20 (15) ◽  
Author(s):  
M. A. F. JALAL ◽  
M. B. HOSSAIN ◽  
D. VAN DER HELM ◽  
J. SANDERS-LOEHR ◽  
L. A. ACTIS ◽  
...  

2021 ◽  
Author(s):  
Jaime G. Lopez ◽  
Mohamed S. Donia ◽  
Ned S. Wingreen

AbstractPlasmids are autonomous genetic elements that can be exchanged between microorganisms via horizontal gene transfer (HGT). Despite the central role they play in antibiotic resistance and modern biotechnology, our understanding of plasmids’ natural ecology is limited. Recent experiments have shown that plasmids can spread even when they are a burden to the cell, suggesting that natural plasmids may exist as parasites. Here, we use mathematical modeling to explore the ecology of such parasitic plasmids. We first develop models of single plasmids and find that a plasmid’s population dynamics and optimal infection strategy are strongly determined by the plasmid’s HGT mechanism. We then analyze models of co-infecting plasmids and show that parasitic plasmids are prone to a “tragedy of the commons” in which runaway plasmid invasion severely reduces host fitness. We propose that this tragedy of the commons is averted by selection between competing populations and demonstrate this effect in a metapopulation model. We derive predicted distributions of unique plasmid types in genomes—comparison to the distribution of plasmids in a collection of 17,725 genomes supports a model of parasitic plasmids with positive plasmid–plasmid interactions that ameliorate plasmid fitness costs or promote the invasion of new plasmids.


Apmis ◽  
1990 ◽  
Vol 98 (1-6) ◽  
pp. 25-29 ◽  
Author(s):  
HENNING SØRum ◽  
KJELL BØVre ◽  
GEIR Bukholm ◽  
JØRGEN Lassen ◽  
ØRJAN Olsvik

2021 ◽  
Author(s):  
Liliane Costa Conteville ◽  
Ana Carolina Paulo Vicente

ABSTRACTThe plasmidome, the set of plasmids in gut microbiomes, has the potential to contribute to the microbiome assembly, as well as human health and physiology. Nevertheless, this niche remains poorly explored, likely due to the difficulties attributed to mining mobile elements from complex environments such as microbiomes. In general, most microbiome studies focus on urban-industrialized groups, but here, we studied semi-isolated groups, which represent a link between the ancestral and modern human groups. Based on metagenomic data, we characterized their plasmidome, including the set of accessory genes and functions from the gut microbiome of the Hadza, Matses, Tunapuco, and Yanomami. In silico analyzes revealed unique plasmid clusters and gene functions for each human group related to their diet and lifestyle. In addition, network analysis revealed a dozen plasmid clusters shared by these distinct groups but that are also circulating in other niches worldwide. Moreover, in these microbiomes, there are novel and unique plasmids associated with their resistome and virulome. A resistome encompassing six antibiotic classes and multiple metals, and a virulome with type VI secretion systems were identified. Functional analysis revealed pathways associated with urban-industrialized groups, such as lipopolysaccharide biosynthesis that was characterized in the Hadza plasmidome. These results demonstrate the richness of features in the semi-isolated human groups’ plasmidome and provide a snapshot of the forces that are acting in their gut microbiome. Their plasmidomes also represent an important source of information with biotechnological and/or pharmaceutical potential.


2020 ◽  
Author(s):  
Fabian Panter ◽  
Chantal D. Bader ◽  
Rolf Müller

AbstractSoil dwelling bacteria such as myxobacteria defend themselves by using secondary metabolites to inhibit growth of competing microorganisms. In this work we describe a new plasmid found in Sandaracinus sp. MSr10575 named pSa001 spanning 209.7 kbp that harbors a cryptic secondary metabolite biosynthesis gene cluster (BGC). Activation of this BGC by homologous recombination mediated exchange of the native promoter sequence against a vanillate inducible system led to production and subsequent isolation and structure elucidation of novel secondary metabolites, the sandarazols A-G. The sandarazol structure contains intriguing features such as an α-chlorinated ketone, an epoxyketone and a (2R)-2-amino-3- (N,N-dimethylamino)-propionic acid building block. In depth investigation of the underlying biosynthetic machinery led to a concise biosynthetic model for the new compound family, including several uncommon biosynthesis steps. The chlorinated congener sandarazol C shows an IC50 value of 0.5 µM against HCT 116 cells and a MIC of 14 µM against Mycobacterium smegmatis, which points at the sandarazol’s potential function as defensive secondary metabolites or toxins. The sandara-zols’ BGC location on pSa001 is one of the very few example of large multimodular BGCs on a replicative plasmid, whose existence points at the mechanism of horizontal gene transfer events of entire multimodular BGCs to exchange chemical warfare capabilities between bacterial species.


mSphere ◽  
2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Ryuichi Nakano ◽  
Akiyo Nakano ◽  
Hisakazu Yano ◽  
Ryoichi Okamoto

ABSTRACT CFE-1 is a unique plasmid-encoded AmpC β-lactamase with the regulator gene ampR. It imparts high resistance to most cephalosporins with constitutive high-level β-lactamase activity. CFE-1 is a unique plasmid-encoded AmpC β-lactamase with the regulator gene ampR. It imparts high resistance to most cephalosporins with constitutive high-level β-lactamase activity. Here, the β-lactamase activities and expression levels of ampC with or without ampR were investigated. Results suggested that the resistance of CFE-1 to cephalosporins is caused by a substitution in AmpR, in which the Asp at position 135 is modified to Ala to allow the constitutive high-level expression (derepression) of ampC.


PLoS ONE ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. e32911 ◽  
Author(s):  
Mark Eppinger ◽  
Lyndsay Radnedge ◽  
Gary Andersen ◽  
Nicholas Vietri ◽  
Grant Severson ◽  
...  

1982 ◽  
Vol 79 (1) ◽  
pp. 1-5 ◽  
Author(s):  
A. K. Weissinger ◽  
D. H. Timothy ◽  
C. S. Levings ◽  
W. W. L. Hu ◽  
M. M. Goodman

2007 ◽  
Vol 74 (1) ◽  
pp. 125-129 ◽  
Author(s):  
Arturo Reyes-Ramírez ◽  
Jorge E. Ibarra

ABSTRACT Practically all Bacillus thuringiensis strains contain a set of self-replicating, extrachromosomal DNA molecules or plasmids, which vary in number and size in the different strains. The plasmid patterns obtained from gel electrophoresis have previously been used as a tool to characterize strains, but comparison of the plasmid patterns has been limited in the number and diversity of strains analyzed. In this report, we were able to compare the plasmid patterns of 83 type strains (out of 84) and 47 additional strains from six serotypes. The information obtained from this comparison showed the importance of this tool as a strain characterization procedure and indicates the complexity and uniqueness of this feature. For example, with one exception, all type strains showed a unique plasmid pattern. All were unique in such a way that none showed even a single comigrating plasmid in the agarose gels, and therefore, cluster analysis was impossible, indicating that plasmid patterns are qualitative rather than quantitative features. Furthermore, comparison between strains belonging to the same serotype showed a great difference in variability. Some serotypes (e.g., israelensis) showed the same basic pattern among all its strains, while other serotypes (e.g., morrisoni) showed a great diversity of patterns. These results indicate that plasmid patterns are valuable tools to discriminate strains below the serotype level.


1989 ◽  
Vol 111 (1) ◽  
pp. 292-296 ◽  
Author(s):  
M. A. F. Jalal ◽  
M. B. Hossain ◽  
Dick Van der Helm ◽  
J. Sanders-Loehr ◽  
L. A. Actis ◽  
...  

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