scholarly journals The Myxococcus xanthus FprA protein causes increased flavin biosynthesis in Escherichia coli.

1990 ◽  
Vol 172 (1) ◽  
pp. 24-30 ◽  
Author(s):  
L J Shimkets
Keyword(s):  
Escherichia Coli ◽  
Myxococcus Xanthus ◽  
Flavin Biosynthesis

scholarly journals Experimental evolution of a microbial predator's ability to find prey

2008 ◽  
Vol 276 (1656) ◽  
pp. 459-467 ◽  
Author(s):  
Kristina L Hillesland ◽  
Gregory J Velicer ◽  
Richard E Lenski
Keyword(s):  
Escherichia Coli ◽  
Experimental Evolution ◽  
Prey Density ◽  
Myxococcus Xanthus ◽  
Foraging Theory ◽  
High Density ◽  
Fruiting Bodies ◽  
Predatory Behaviour ◽  
Handling Performance

Foraging theory seeks to explain how the distribution and abundance of prey influence the evolution of predatory behaviour, including the allocation of effort to searching for prey and handling them after they are found. While experiments have shown that many predators alter their behaviour phenotypically within individual lifetimes, few have examined the actual evolution of predatory behaviour in light of this theory. Here, we test the effects of prey density on the evolution of a predator's searching and handling behaviours using a bacterial predator, Myxococcus xanthus . Sixteen predator populations evolved for almost a year on agar surfaces containing patches of Escherichia coli prey at low or high density. Improvements in searching rate were significantly greater in those predators that evolved at low prey density. Handling performance also improved in some predator populations, but prey density did not significantly affect the magnitude of these gains. As the predators evolved greater foraging proficiency, their capacity diminished to produce fruiting bodies that enable them to survive prolonged periods of starvation. More generally, these results demonstrate that predators evolve behaviours that reflect at least some of the opportunities and limitations imposed by the distribution and abundance of their prey.

scholarly journals Killing of Escherichia coli by Myxococcus xanthus in Aqueous Environments Requires Exopolysaccharide-Dependent Physical Contact

2013 ◽  
Vol 66 (3) ◽  
pp. 630-638 ◽  
Author(s):  
Hongwei Pan ◽  
Xuesong He ◽  
Renate Lux ◽  
Jia Luan ◽  
Wenyuan Shi
Keyword(s):  
Escherichia Coli ◽  
Myxococcus Xanthus ◽  
Physical Contact ◽  
Aqueous Environments

scholarly journals Cloning and Expression of clt Genes Encoding Milk-Clotting Proteases from Myxococcus xanthus 422

2004 ◽  
Vol 70 (10) ◽  
pp. 6337-6341 ◽  
Author(s):  
M. Poza ◽  
M. Prieto-Alcedo ◽  
C. Sieiro ◽  
T. G. Villa
Keyword(s):  
Escherichia Coli ◽  
Myxococcus Xanthus ◽  
Open Reading Frames ◽  
Cloning And Expression ◽  
Gene Library ◽  
Expression Systems ◽  
E Coli ◽  
Milk Clotting ◽  
Genes Encoding ◽  
Reading Frames

ABSTRACT The screening of a gene library of the milk-clotting strain Myxococcus xanthus 422 constructed in Escherichia coli allowed the description of eight positive clones containing 26 open reading frames. Only three of them (cltA, cltB, and cltC) encoded proteins that exhibited intracellular milk-clotting ability in E. coli, Saccharomyces cerevisiae, and Pichia pastoris expression systems.

scholarly journals Dynamics of Solitary Predation by Myxococcus xanthus on Escherichia coli Observed at the Single-Cell Level

2019 ◽  
Vol 86 (3) ◽  
Author(s):  
Wenchao Zhang ◽  
Yan Wang ◽  
Huining Lu ◽  
Qin Liu ◽  
Chuandong Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Single Cell ◽  
Myxococcus Xanthus ◽  
Predatory Behavior ◽  
Single Cell Level ◽  
Cell Level ◽  
Prey Cell ◽  
Content Type ◽  
E Coli ◽  
Tracking Technique

ABSTRACT The predatory behavior of Myxococcus xanthus has attracted extensive attention due to its unique social traits and inherent biological activities. In addition to group hunting, individual M. xanthus cells are able to kill and lyse prey cells; however, there is little understanding of the dynamics of solitary predation. In this study, by employing a bacterial tracking technique, we investigated M. xanthus predatory dynamics on Escherichia coli at the single-cell level. The killing and lysis of E. coli by a single M. xanthus cell was monitored in real time by microscopic observation, and the plasmolysis of prey cells was identified at a relatively early stage of solitary predation. After quantitative characterization of their solitary predatory behavior, M. xanthus cells were found to respond more dramatically to direct contact with live E. coli cells than heat-killed or UV-killed cells, showing slower predator motion and faster lysing of prey. Among the three contact-dependent killing modes classified according to the major subareas of M. xanthus cells in contact with prey, leading pole contact was observed most. After killing the prey, approximately 72% of M. xanthus cells were found to leave without thorough degradation of the lysed prey, and this postresidence behavior is described as a lysis-leave pattern, indicating that solitary predation has low efficiency in terms of prey-cell consumption. Our results provide a detailed description of the single-cell level dynamics of M. xanthus solitary predation from both prey and predator perspectives. IMPORTANCE Bacterial predation plays multiple essential roles in bacterial selection and mortality within microbial ecosystems. In addition to its ecological and evolutionary importance, many potential applications of bacterial predation have been proposed. The myxobacterium Myxococcus xanthus is a well-known predatory member of the soil microbial community. Its predation is commonly considered a collective behavior comparable to a wolf pack attack; however, individual M. xanthus cells are also able to competently lead to the lysis of a prey cell. Using a bacterial tracking technique, we are able to observe and analyze solitary predation by M. xanthus on Escherichia coli at the single-cell level and reveal the dynamics of both predator and prey during the process. The present study will not only provide a comprehensive understanding of M. xanthus solitary predation but also help to explain why M. xanthus often displays multicellular characteristic predatory behaviors in nature, while a single cell is capable of predation.

scholarly journals Growth responses of Escherichia coli and Myxococcus xanthus on agar gel substrates with different levels of stiffness

2012 ◽  
Vol 11 (88) ◽  
pp. 15477-15483 ◽  
Author(s):  
PARK Eun Jung ◽  
CHO Myoung Ock ◽  
LEE Donghee ◽  
Kyung KIM Jung
Keyword(s):  
Escherichia Coli ◽  
Myxococcus Xanthus ◽  
Growth Responses ◽  
Agar Gel ◽  
Different Levels

scholarly journals Regulation of dev, an Operon That Includes Genes Essential for Myxococcus xanthus Development and CRISPR-Associated Genes and Repeats

2007 ◽  
Vol 189 (10) ◽  
pp. 3738-3750 ◽  
Author(s):  
Poorna Viswanathan ◽  
Kimberly Murphy ◽  
Bryan Julien ◽  
Anthony G. Garza ◽  
Lee Kroos
Keyword(s):  
Escherichia Coli ◽  
Promoter Activity ◽  
Myxococcus Xanthus ◽  
Regulatory Elements ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Coding Region ◽  
Upstream Gene ◽  
Negative Element ◽  
Growth Induction

ABSTRACT Expression of dev genes is important for triggering spore differentiation inside Myxococcus xanthus fruiting bodies. DNA sequence analysis suggested that dev and cas (CRISPR-associated) genes are cotranscribed at the dev locus, which is adjacent to CRISPR (clustered regularly interspaced short palindromic repeats). Analysis of RNA from developing M. xanthus confirmed that dev and cas genes are cotranscribed with a short upstream gene and at least two repeats of the downstream CRISPR, forming the dev operon. The operon is subject to strong, negative autoregulation during development by DevS. The dev promoter was identified. Its −35 and −10 regions resemble those recognized by M. xanthus σA RNA polymerase, the homolog of Escherichia coli σ70, but the spacer may be too long (20 bp); there is very little expression during growth. Induction during development relies on at least two positive regulatory elements located in the coding region of the next gene upstream. At least two positive regulatory elements and one negative element lie downstream of the dev promoter, such that the region controlling dev expression spans more than 1 kb. The results of testing different fragments for dev promoter activity in wild-type and devS mutant backgrounds strongly suggest that upstream and downstream regulatory elements interact functionally. Strikingly, the 37-bp sequence between the two CRISPR repeats that, minimally, are cotranscribed with dev and cas genes exactly matches a sequence in the bacteriophage Mx8 intP gene, which encodes a form of the integrase needed for lysogenization of M. xanthus.

scholarly journals Characterization of SafC, a Catechol 4-O-Methyltransferase Involved in Saframycin Biosynthesis

2007 ◽  
Vol 73 (11) ◽  
pp. 3575-3580 ◽  
Author(s):  
James T. Nelson ◽  
Jaeheon Lee ◽  
James W. Sims ◽  
Eric W. Schmidt
Keyword(s):  
Escherichia Coli ◽  
Natural Products ◽  
Caffeic Acid ◽  
Antitumor Agents ◽  
Myxococcus Xanthus ◽  
Clinical Development ◽  
Nonribosomal Peptide Synthetase ◽  
Biotechnological Potential ◽  
Peptide Synthetase

ABSTRACT Members of the saframycin/safracin/ecteinascidin family of peptide natural products are potent antitumor agents currently under clinical development. Saframycin MX1, from Myxococcus xanthus, is synthesized by a nonribosomal peptide synthetase, SafAB, and an O-methyltransferase, SafC, although other proteins are likely involved in the pathway. SafC was overexpressed in Escherichia coli, purified to homogeneity, and assayed for its ability to methylate a variety of substrates. SafC was able to catalyze the O-methylation of catechol derivatives but not phenols. Among the substrates tested, the best substrate for SafC was l-dihydroxyphenylalanine (l-dopa), which was methylated specifically in the 4′-O position (k cat/Km = 5.5 × 103 M−1 s−1). SafC displayed less activity on other catechol derivatives, including catechol, dopamine, and caffeic acid. The more labile l-5′-methyldopa was an extremely poor substrate for SafC (k cat/Km = ∼2.8 × 10−5 M−1 s−1). l-Dopa thioester derivatives were also much less reactive than l-dopa. These results indicate that SafC-catalyzed 4′-O-methylation of l-dopa occurs prior to 5′-C-methylation, suggesting that 4′-O-methylation is likely the first committed step in the biosynthesis of saframycin MX1. SafC has biotechnological potential as a methyltransferase with unique regioselectivity.

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