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

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.

Download Full-text

Characterization of Escherichia coli ExbD protein modification in vivo

10.1101/2020.01.29.925446 ◽

2020 ◽

Author(s):

Aruna Kumar ◽

Kathleen Postle

Keyword(s):

Escherichia Coli ◽

Outer Membrane ◽

Active Transport ◽

Protein Modification ◽

Cytoplasmic Membrane ◽

Physical Contact ◽

Protonmotive Force ◽

Iron Starvation ◽

Tonb System

ABSTRACTThe TonB system of Escherichia coli couples the protonmotive force of the cytoplasmic membrane to active transport of nutrients across the outer membrane. In the cytoplasmic membrane, this system consists of three known proteins, TonB, ExbB, and ExbD. ExbB and ExbD appear to harvest the protonmotive force and transmit it to TonB, which then makes direct physical contact with TonB-dependent active transport proteins in the outer membrane. Using two-dimensional gel electrophoresis, we found that ExbD exists as two different species with the same apparent molecular mass but with different pIs. The more basic ExbD species was consistently present, while the more acidic species arose when cells were starved for iron by the addition of iron chelators. The cause of the modification was, however, more complex than simple iron starvation. Absence of either TonB or ExbB protein also gave rise to modified ExbD under iron-replete conditions where the wild-type strain exhibited no ExbD modification. The effect of the tonB or exbB mutations were not entirely due to iron limitation since an equally iron-limited aroB mutation did not replicate the ExbD modification. This constitutes the first report of in vivo modification for any of the TonB system proteins.

Download Full-text

An outbreak of Shiga toxin-producing Escherichia coli serogroup O157 linked to a lamb-feeding event

Epidemiology and Infection ◽

10.1017/s0950268816001229 ◽

2016 ◽

Vol 144 (12) ◽

pp. 2494-2500 ◽

Cited By ~ 13

Author(s):

S. ROWELL ◽

C. KING ◽

C. JENKINS ◽

T. J. DALLMAN ◽

V. DECRAENE ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Phage Type ◽

Variable Number Tandem Repeat ◽

Variable Number ◽

Bottle Feeding ◽

Control Measures ◽

Physical Contact ◽

Sequencing Analysis ◽

North West

SUMMARYFifteen confirmed cases and 15 possible cases of Shiga toxin-producing Escherichia coli (STEC) O157 phage type 21/28 were linked to direct contact with lambs at a ‘Lambing Live’ event in the North West of England between 29 March and 21 April 2014. Twenty-one (70%) of the cases were female, 23 (77%) were children aged <16 years, of whom 14 (46%) were in the 0–5 years age group. Five children developed haemolytic uraemic syndrome. Multilocus variable number tandem repeat analysis (MLVA) profiles on 14 human cases were indistinguishable, and 6/10 animal isolates had a MLVA profile identical to the outbreak profile. Whole-genome sequencing analysis revealed that all isolates, both human and animal, fell within a 5-single nucleotide polymorphism cluster indicating the isolates belonged to the same point source. On inspection of the premises, extensive and uncontrolled physical contact between visitors and animals was occuring within the animal pens and during bottle-feeding. Public areas were visibly contaminated with animal faeces. Information to visitors, and the infection control awareness demonstrated by staff, was inadequate. Managing the risk to visitors of STEC O157 infection at animal petting events and open farms requires implementation of stringent control measures by the operator, as outlined in the industry code of practice. Enforcement action is sometimes required to prevent high-risk activities taking place at both permanent and temporary attractions.

Download Full-text

Escherichia coli pH 2.5 acid phosphatase and β-lactamase TEM2 are secreted into the medium by Myxococcus xanthus

FEMS Microbiology Letters ◽

10.1016/0378-1097(87)90373-9 ◽

1987 ◽

Vol 40 (2-3) ◽

pp. 183-188

Author(s):

A Breton

Keyword(s):

Escherichia Coli ◽

Acid Phosphatase ◽

Myxococcus Xanthus

Download Full-text

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

Applied and Environmental Microbiology ◽

10.1128/aem.70.10.6337-6341.2004 ◽

2004 ◽

Vol 70 (10) ◽

pp. 6337-6341 ◽

Cited By ~ 16

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.

Download Full-text

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

Applied and Environmental Microbiology ◽

10.1128/aem.02286-19 ◽

2019 ◽

Vol 86 (3) ◽

Cited By ~ 1

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.

Download Full-text

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

AFRICAN JOURNAL OF BIOTECHNOLOGY ◽

10.5897/ajb12.1294 ◽

2012 ◽

Vol 11 (88) ◽

pp. 15477-15483 ◽

Cited By ~ 2

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

Download Full-text

Combining epidemiological and ecological methods to quantify social effects on Escherichia coli transmission

Royal Society Open Science ◽

10.1098/rsos.210328 ◽

2021 ◽

Vol 8 (10) ◽

Author(s):

Trevor S. Farthing ◽

Daniel E. Dawson ◽

Mike W. Sanderson ◽

Hannah Seger ◽

Cristina Lanzas

Keyword(s):

Escherichia Coli ◽

Real Time ◽

Failure Time ◽

Bos Taurus ◽

Feedlot Cattle ◽

Physical Contact ◽

Transmission Risk ◽

E Coli ◽

Location Data ◽

Relative Transmission

Enteric microparasites like Escherichia coli use multiple transmission pathways to propagate within and between host populations. Characterizing the relative transmission risk attributable to host social relationships and direct physical contact between individuals is paramount for understanding how microparasites like E. coli spread within affected communities and estimating colonization rates. To measure these effects, we carried out commensal E. coli transmission experiments in two cattle ( Bos taurus ) herds, wherein all individuals were equipped with real-time location tracking devices. Following transmission experiments in this model system, we derived temporally dynamic social and contact networks from location data. Estimated social affiliations and dyadic contact frequencies during transmission experiments informed pairwise accelerated failure time models that we used to quantify effects of these sociobehavioural variables on weekly E. coli colonization risk in these populations. We found that sociobehavioural variables alone were ultimately poor predictors of E. coli colonization in feedlot cattle, but can have significant effects on colonization hazard rates ( p ≤ 0.05). We show, however, that observed effects were not consistent between similar populations. This work demonstrates that transmission experiments can be combined with real-time location data collection and processing procedures to create an effective framework for quantifying sociobehavioural effects on microparasite transmission.

Download Full-text

Thiamine-Mediated Cooperation Between Auxotrophic Rhodococcus ruber ZM07 and Escherichia coli K12 Drives Efficient Tetrahydrofuran Degradation

Frontiers in Microbiology ◽

10.3389/fmicb.2020.594052 ◽

2020 ◽

Vol 11 ◽

Author(s):

Hui Huang ◽

Minbo Qi ◽

Yiming Liu ◽

Haixia Wang ◽

Xuejun Wang ◽

...

Keyword(s):

Escherichia Coli ◽

Relative Abundance ◽

Intraspecific Competition ◽

Enrichment Culture ◽

Physical Contact ◽

Rhodococcus Ruber ◽

Free Medium ◽

Degrading Bacterium ◽

Extracellular Metabolites ◽

Insight Into

Tetrahydrofuran (THF) is a universal solvent widely used in the synthesis of chemicals and pharmaceuticals. As a refractory organic contaminant, it can only be degraded by a small group of microbes. In this study, a thiamine auxotrophic THF-degrading bacterium, Rhodococcus ruber ZM07, was isolated from an enrichment culture H-1. It was cocultured with Escherichia coli K12 (which cannot degrade THF but can produce thiamine) and/or Escherichia coli K12ΔthiE (which can neither degrade THF nor produce thiamine) with or without exogenous thiamine. This study aims to understand the interaction mechanisms between ZM07 and K12. We found that K12 accounted for 30% of the total when cocultured and transferred with ZM07 in thiamine-free systems; in addition, in the three-strain (ZM07, K12, and K12ΔthiE) cocultured system without thiamine, K12ΔthiE disappeared in the 8th transfer, while K12 could still stably exist (the relative abundance remained at approximately 30%). The growth of K12 was significantly inhibited in the thiamine-rich system. Its proportion was almost below 4% after the fourth transfer in both the two-strain (ZM07 and K12) and three-strain (ZM07, K12, and K12ΔthiE) systems; K12ΔthiE’s percentage was higher than K12’s in the three-strain (ZM07, K12, and K12ΔthiE) cocultured system with exogenous thiamine, and both represented only a small proportion (less than 1% by the fourth transfer). The results of the coculture of K12 and K12ΔthiE in thiamine-free medium indicated that intraspecific competition between them may be one of the main reasons for the extinction of K12ΔthiE in the three-strain (ZM07, K12, and K12ΔthiE) system without exogenous thiamine. Furthermore, we found that ZM07 could cooperate with K12 through extracellular metabolites exchanges without physical contact. This study provides novel insight into how microbes cooperate and compete with one another during THF degradation.

Download Full-text