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swarming motility

Bing Guo, Yongqiang Zhang, Shili Li, Ting Lai, Liang Yang, Juanni Chen, Wei Ding
Many cereals accumulate hydroxamic acids involved in defense of plant against various fungi, bacteria, and insects. 2,4-dihydroxy-7-methoxy-1,4-benzoxazine-3-one, commonly known as DIMBOA, is one of the principal cyclic hydroxamic acids in aqueous extracts of maize. The aim of this study was to evaluate the antibacterial activity of the isolated DIMBOA and its derivatives 2-benzoxazolinone (BOA), 6-chloro-2-benzoxazolinone (CDHB), and 2-mercaptobenzothiazole (MBT) against Ralstonia solanacearum. MBT showed the strongest antibacterial activity, followed by CDHB and DIMBOA, with minimum inhibitory concentrations (MICs) of 50, 100 and 200 mg/L, respectively, better than the BOA with 300 mg/L...
October 19, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Oihane Irazoki, Jesús Aranda, Timo Zimmermann, Susana Campoy, Jordi Barbé
In addition to its role in DNA damage repair and recombination, the RecA protein, through its interaction with CheW, is involved in swarming motility, a form of flagella-dependent movement across surfaces. In order to better understand how SOS response modulates swarming, in this work the location of RecA and CheW proteins within the swarming cells has been studied by using super-resolution microscopy. Further, and after in silico docking studies, the specific RecA and CheW regions associated with the RecA-CheW interaction have also been confirmed by site-directed mutagenesis and immunoprecipitation techniques...
2016: Frontiers in Microbiology
Ramanathan Srinivasan, Kannan Rama Devi, Arunachalam Kannappan, Shunmugiah Karutha Pandian, Arumugam Veera Ravi
ETHNOPHARMACOLOGICAL RELEVANCE: Piper betle, a tropical creeper plant belongs to the family Piperaceae. The leaves of this plant have been well known for their therapeutic, religious and ceremonial value in South and Southeast Asia. It has also been reported to possess several biological activities including antimicrobial, antioxidant, antinociceptive, antidiabetic, insecticidal and gastroprotective activities and used as a common ingredient in indigenous medicines. In Indian system of ayurvedic medicine, P...
October 6, 2016: Journal of Ethnopharmacology
Christina C Saak, Karine A Gibbs
Proteus mirabilis is a social bacterium that is capable of self (kin) versus non-self recognition. Swarming colonies of this bacterium expand outward on surfaces at centimeter-scale distances due to the collective motility of individual cells. Colonies of genetically distinct populations remain separate while those of identical populations merge. Ids proteins are essential for this recognition behavior. Two of these proteins, IdsD and IdsE, encode identity information for each strain. These two proteins bind in vitro in an allele-restrictive manner, and IdsD-IdsE binding is correlated with populations merging whereas a lack of binding correlates with populations separating...
September 26, 2016: Journal of Bacteriology
Liaoyuan Zhang, Zewang Guo, Hufang Gao, XiaoQian Peng, Yongyu Li, Shujing Sun, Jung-Kul Lee, Wenxiong Lin
Many plant-pathogenic bacteria were dependent on quorum sensing (QS) to evoke disease. In this study, the population of QS and quorum quenching (QQ) bacteria was analyzed in consecutive monoculture system of Pseudostellaria heterophylla. The isolated QS strains were identified as Serratia marcescens with SwrIR-type QS system and exhibited a significant increase over the years of monoculture. Only one QQ strain was isolated from new planted soil sample and identified as Bacillus thuringiensis which secreted lactonase to degrade QS signal molecules...
September 23, 2016: Journal of Microbiology and Biotechnology
Olaya Rendueles, Gregory J Velicer
Evolutionary adaptation can be achieved by mechanisms accessible to all organisms, including faster growth and interference competition, but self-generated motility offers additional possibilities. We tested whether 55 populations of the bacterium Myxococcus xanthus that underwent selection for increased fitness at the leading edge of swarming colonies adapted by swarming faster toward unused resources or by other means. Populations adapted greatly but diversified markedly in both swarming phenotypes and apparent mechanisms of adaptation...
September 23, 2016: ISME Journal
James G Lefevre, Alexander N Combes, Melissa H Little, Nicholas A Hamilton
This article provides detailed information on manually tracked cap mesenchyme cells from timelapse imaging of multiple ex vivo embryonic mouse kidneys. Cells were imaged for up to 18 h at 15 or 20 min intervals, and multiple cell divisions were tracked. Positional data is supplemented with a range of information including the relative location of the closest ureteric tip and a correction for drift due to bulk movement and tip growth. A subset of tracks were annotated to indicate the presence of processes attached to the ureteric epithelium...
December 2016: Data in Brief
Weng Chun Tan, Nor Ashidi Mat Isa
In human sperm motility analysis, sperm segmentation plays an important role to determine the location of multiple sperms. To ensure an improved segmentation result, the Laplacian of Gaussian filter is implemented as a kernel in a pre-processing step before applying the image segmentation process to automatically segment and detect human spermatozoa. This study proposes an intersecting cortical model (ICM), which was derived from several visual cortex models, to segment the sperm head region. However, the proposed method suffered from parameter selection; thus, the ICM network is optimised using particle swarm optimization where feature mutual information is introduced as the new fitness function...
2016: PloS One
Yijing Zhuang, Weidong Chen, Fen Yao, Yuanchun Huang, Shuqin Zhou, Haiyan Li, Zijie Zhang, Congyi Cai, Yi Gao, Qing Peng
BACKGROUND/AIMS: Motility is a feature of many pathogens that contributes to the migration and dispersion of the infectious agent. Whether gentamycin has a post-antibiotic effect (PAE) on the swarming and swimming motility of Escherichia coli (E. coli) remains unknown. In this study, we aimed to examine whether short-term pretreatment of sub-inhibitory concentrations of gentamycin alter motility of E. coli and the mechanisms involved therein. METHODS: After exposure to sub-inhibitory concentrations (0...
2016: Cellular Physiology and Biochemistry
Ye Jin Kim, So Young Im, Jae Ok Lee, Ok Bin Kim
AcrR, the toxic-compounds-response regulator, regulates motility in microorganisms, presumably to escape from toxic environments. In this study, the genome-wide target genes of AcrR were investigated in a ∆acrR mutant strain by microarray analysis. In the absence of AcrR, the transcription of most flagella/motility genes was highly increased. In addition, flagella formation was increased in this mutant strain. Motility assays revealed that AcrR modulates swimming motility, but not swarming.
August 24, 2016: Journal of Microbiology and Biotechnology
Arvin Nickzad, Eric Déziel
Quorum sensing (QS) is a cell density-dependent mechanism which enables a population of bacteria to coordinate cooperative behaviors in response to the accumulation of self-produced autoinducer signals in their local environment. An emerging framework is that the adaptive significance of QS in the regulation of production of costly extracellular metabolites ("public goods") is to maintain the homeostasis of cooperation. We investigated this model using the phytopathogenic bacterium Burkholderia glumae, which we have previously demonstrated uses QS to regulate the production of rhamnolipids, extracellular surface-active glycolipids promoting the social behavior called "swarming motility...
2016: Frontiers in Microbiology
Weixia Gao, Fenghong Liu, Wei Zhang, Yufen Quan, Yulei Dang, Jun Feng, Yanyan Gu, Shufang Wang, Cunjiang Song, Chao Yang
Poly-γ-glutamic acid (γ-PGA) is an important natural biopolymer that is used widely in fields of foods, medicine, cosmetics, and agriculture. Several B. amyloliquefaciens LL3 mutants were constructed to improve γ-PGA synthesis via single or multiple marker-less in-frame deletions of four gene clusters (itu, bae, srf, and fen) encoding antibiotic substances. γ-PGA synthesis by the Δsrf mutant showed a slight increase (4.1 g/L) compared with that of the wild-type strain (3.3 g/L). The ΔituΔsrf mutant showed increased γ-PGA yield from 3...
August 18, 2016: MicrobiologyOpen
Linda Turner, Liam Ping, Marianna Neubauer, Howard C Berg
A complete description of the swimming behavior of a bacterium requires measurement of the displacement and orientation of the cell body together with a description of the movement of the flagella. We rebuilt a tracking microscope so that we could visualize flagellar filaments of tracked cells by fluorescence. We studied Escherichia coli (cells of various lengths, including swarm cells), Bacillus subtilis (wild-type and a mutant with fewer flagella), and a motile Streptococcus (now Enterococcus). The run-and-tumble statistics were nearly the same regardless of cell shape, length, and flagellation; however, swarm cells rarely tumbled, and cells of Enterococcus tended to swim in loops when moving slowly...
August 9, 2016: Biophysical Journal
Saeed Hosseinzadeh, Masoud Shams-Bakhsh, Majid Sadeghizadeh
N-Acyl-homoserine lactones (AHLs)-dependent quorum sensing (QS) system(s) is recruited by the soft rot bacterium Dickeya chrysanthemi for coordinating its social activities such as secretion of plant cell wall-degrading enzymes, while the main signal molecule and quantity dependence of virulence to QS in this bacterium have not been clarified. To do this end, the involvement of AHLs in African violet leaves and potato tuber maceration; swarming motility; pectate lyase and polygalacturonase enzymes production and in planta expression of virulence genes including pelE, pehX and pemA by electroporating two quorum-quenching vectors...
August 5, 2016: Archives of Microbiology
Benjamin M Hariri, Sakeena J Payne, Bei Chen, Corrine Mansfield, Laurel J Doghramji, Nithin D Adappa, James N Palmer, David W Kennedy, Masha Y Niv, Robert J Lee
BACKGROUND: T2R bitter taste receptors play a crucial role in sinonasal innate immunity by upregulating mucociliary clearance and nitric oxide (NO) production in response to bitter gram-negative quorum-sensing molecules in the airway surface liquid. Previous studies showed that phytochemical flavonoid metabolites, known as anthocyanidins, taste bitter and have antibacterial effects. Our objectives were to examine the effects of anthocyanidins on NO production by human sinonasal epithelial cells and ciliary beat frequency, and their impact on common sinonasal pathogens Pseudomonas aeruginosa and Staphylococcus aureus...
July 2016: American Journal of Rhinology & Allergy
Dashuai Mu, Xiuxia Yu, Zhenxing Xu, Zongjun Du, Guanjun Chen
An increasing number of studies have investigated the effects of nanoparticles (NPs) on microbial systems; however, few existing reports have focused on the defense mechanisms of bacteria against NPs. Whether secondary metabolism biosynthesis is a response to NP stress and contributes to the adaption of bacteria to NPs is unclear. Here, a significant induction in the surfactin production and biofilm formation were detected by adding Al2O3 NPs to the B. subtilis fermentation broth. Physiological analysis showed that Al2O3 NP stress could also affect the cell and colony morphogenesis and inhibit the motility and sporulation...
2016: Scientific Reports
Óscar Huertas-Rosales, María Isabel Ramos-González, Manuel Espinosa-Urgel
UNLABELLED: In the plant-beneficial bacterium Pseudomonas putida KT2440, three genes have been identified that encode posttranscriptional regulators of the CsrA/RsmA family. Their regulatory roles in the motile and sessile lifestyles of P. putida have been investigated by generating single-, double-, and triple-null mutants and by overexpressing each protein (RsmA, RsmE, and RsmI) in different genetic backgrounds. The rsm triple mutant shows reduced swimming and swarming motilities and increased biofilm formation, whereas overexpression of RsmE or RsmI results in reduced bacterial attachment...
September 15, 2016: Applied and Environmental Microbiology
Jing Yan, Ming Han, Jie Zhang, Cong Xu, Erik Luijten, Steve Granick
Active materials represent a new class of condensed matter in which motile elements may collectively form dynamic, global structures out of equilibrium. Here, we present a general strategy to reconfigure active particles into various collective states by introducing imbalanced interactions. We demonstrate the concept with computer simulations of self-propelled colloidal spheres, and experimentally validate it in a two-dimensional (2D) system of metal-dielectric Janus colloids subjected to perpendicular a.c...
October 2016: Nature Materials
Fei Yang, Shun Liu, Xiuli Liu, Lei Liu, Meijie Luo, Shuhong Qi, Guoqiang Xu, Sha Qiao, Xiaohua Lv, Xiangning Li, Ling Fu, Qingming Luo, Zhihong Zhang
In vivo optical spatio-temporal imaging of the tumor microenvironment is useful to explain how tumor immunotherapies work. However, the lack of fluorescent antigens with strong immunogenicity makes it difficult to study the dynamics of how tumors are eliminated by any given immune response. Here, we develop an effective fluorescent model antigen based on the tetrameric far-red fluorescent protein KatushkaS158A (tfRFP), which elicits both humoral and cellular immunity. We use this fluorescent antigen to visualize the dynamic behavior of immunocytes as they attack and selectively eliminate tfRFP-expressing tumors in vivo; swarms of immunocytes rush toward tumors with high motility, clusters of immunocytes form quickly, and numerous antigen-antibody complexes in the form of tfRFP(+) microparticles are generated in the tumor areas and ingested by macrophages in the tumor microenvironment...
2016: Theranostics
Alam García-Heredia, Santos García, José Ángel Merino-Mascorro, Peter Feng, Norma Heredia
The purpose of this study was to determine the effects of plant products on the growth, swarming motility, biofilm formation and virulence gene expression in enterohemorrhagic Escherichia coli O157:H7 and enteroaggregative E. coli strain 042 and a strain of O104:H4 serotype. Extracts of Lippia graveolens and Haematoxylon brassiletto, and carvacrol, brazilin were tested by an antimicrobial microdilution method using citral and rifaximin as controls. All products showed bactericidal activity with minimal bactericidal concentrations ranging from 0...
October 2016: Food Microbiology
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