Journal articles on the topic 'Microorganisms – Motility'
To see the other types of publications on this topic, follow the link: Microorganisms – Motility.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Microorganisms – Motility.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Petit, M. D. A., U. Velden, A. J. Winkelhoff, and J. Graaff. "Preserving the motility of microorganisms." Oral Microbiology and Immunology 6, no. 2 (April 1991): 107–10. http://dx.doi.org/10.1111/j.1399-302x.1991.tb00460.x.
Full text
2
Mehdizadeh Allaf, Malihe, and Hassan Peerhossaini. "Cyanobacteria: Model Microorganisms and Beyond." Microorganisms 10, no. 4 (March 24, 2022): 696. http://dx.doi.org/10.3390/microorganisms10040696.
Full textAbstract:
In this review, the general background is provided on cyanobacteria, including morphology, cell membrane structure, and their photosynthesis pathway. The presence of cyanobacteria in nature, and their industrial applications are discussed, and their production of secondary metabolites are explained. Biofilm formation, as a common feature of microorganisms, is detailed and the role of cell diffusion in bacterial colonization is described. Then, the discussion is narrowed down to cyanobacterium Synechocystis, as a lab model microorganism. In this relation, the morphology of Synechocystis is discussed and its different elements are detailed. Type IV pili, the complex multi-protein apparatus for motility and cell-cell adhesion in Synechocystis is described and the underlying function of its different elements is detailed. The phototaxis behavior of the cells, in response to homogenous or directional illumination, is reported and its relation to the run and tumble statistics of the cells is emphasized. In Synechocystis suspensions, there may exist a reciprocal interaction between the cell and the carrying fluid. The effects of shear flow on the growth, doubling per day, biomass production, pigments, and lipid production of Synechocystis are reported. Reciprocally, the effects of Synechocystis presence and its motility on the rheological properties of cell suspensions are addressed. This review only takes up the general grounds of cyanobacteria and does not get into the detailed biological aspects per se. Thus, it is substantially more comprehensive in that sense than other reviews that have been published in the last two decades. It is also written not only for the researchers in the field, but for those in physics and engineering, who may find it interesting, useful, and related to their own research.
3
Grassi, Hilda Cristina, Efrén De Jesús Andrades, María Lorena Lobo, and Jesús Enrique Andrades. "A prototype biospecklemeter for microbiological analysis: a starting point for a potential digital-image laser antibiotic susceptibility test." Laser Physics 32, no. 9 (September 1, 2022): 095604. http://dx.doi.org/10.1088/1555-6611/ac8677.
Full textAbstract:
Abstract This work describes the design and construction of a low-cost prototype biospecklemeter. In this first report of its applications a microbiological analysis was performed. The relationship between microorganism density, motility and biospeckle activity was evaluated. The aim is to produce a device for research and for student use. The biospecklemeter was constructed on an antivibration table with low-cost materials and accessories and assayed using different microorganisms grown in Mueller–Hinton broth and/or agar as well as urine samples. Three lasers were installed (blue, green and red) as well as two webcams and a charge-coupled device camera. The samples were carried within the wells of a VDRL plate and 5–30 s videos or photographs of reflected light were taken. Video or photo processing was carried out using the method of temporal differences (ImageJ) or generalized differences (ImageDP). It was possible to establish a direct relationship between spectrophotometric absorption, the microbial count and the biospeckle intensity; changes in motility and the effect of antibiotics on bacterial laboratory samples as well as on urine samples were also detected. Finally, with this method colonies of different microorganisms on Mueller–Hinton agar were studied.
4
Martínez, Asunción, Sandra Torello, and Roberto Kolter. "Sliding Motility in Mycobacteria." Journal of Bacteriology 181, no. 23 (December 1, 1999): 7331–38. http://dx.doi.org/10.1128/jb.181.23.7331-7338.1999.
Full textAbstract:
ABSTRACT Mycobacteria are nonflagellated gram-positive microorganisms. Previously thought to be nonmotile, we show here thatMycobacterium smegmatis can spread on the surface of growth medium by a sliding mechanism. M. smegmatis spreads as a monolayer of cells which are arranged in pseudofilaments by close cell-to-cell contacts, predominantly along their longitudinal axis. The monolayer moves away from the inoculation point as a unit with only minor rearrangements. No extracellular structures such as pili or fimbriae appear to be involved in this process. The ability to translocate over the surface correlates with the presence of glycopeptidolipids, a mycobacterium-specific class of amphiphilic molecules located in the outermost layer of the cell envelope. We present evidence that surface motility is not restricted to M. smegmatis but is also a property of the slow-growing opportunistic pathogen M. avium. This form of motility could play an important role in surface colonization by mycobacteria in the environment as well as in the host.
5
Varshney, Rohit, Arshdeep Kaur Gill, Mujeeb Alam, Chinmayee Agashe, and Debabrata Patra. "Fluid actuation and buoyancy driven oscillation by enzyme-immobilized microfluidic microcapsules." Lab on a Chip 21, no. 22 (2021): 4352–56. http://dx.doi.org/10.1039/d1lc00699a.
Full textAbstract:
To mimic the life-like complex behavior of microorganisms, enzyme-immobilized microfluidic microcapsules were fabricated to demonstrate the enzyme powered fluid actuation and buoyancy driven motility.
6
Sarbu, Ionela, Tatiana Vassu, Mariana Carmen Chifiriuc, Marcela Bucur, Ileana Stoica, Petrut Stefana, Elena Rusu, Horatiu Moldovan, and Diana Pelinescu. "Assessment the Activity of Some Enzymes and Antibiotic Substances Sensitivity on Pathogenic Bacteria Species." Revista de Chimie 68, no. 12 (January 15, 2018): 3015–21. http://dx.doi.org/10.37358/rc.17.12.6029.
Full textAbstract:
Microbial and opportunistic pathogens cause serious problem to human host by releasing different compounds which are involved in colonization, invasion or in alteration of immune process. In this study we propose ourselves to analyze the virulence profile of microorganisms involved in urinary tract infections and bacterial vaginosis in order to compare the virulence mechanisms developed by these microorganisms. We assessed the virulence profile (motility, adhesion to HeLa cell line, biofilm formation, production of enzymes, antibiotic susceptibility) using phenotypic methods. The microbial strains isolated from urinary tract infections present a high ability to release amylases, caseinase, siderophore-like, half of them have present high motility and also were highly resistant to antibiotics, while the microbial strains isolated from bacterial vaginosis present a high ability to bind human epithelial cells and to release hemolyzin and DN-ase.
7
Sidorova, Daria E., Mariia I. Skripka, Inessa A. Khmel, Olga A. Koksharova, and Vladimir A. Plyuta. "Effects of Volatile Organic Compounds on Biofilms and Swimming Motility of Agrobacterium tumefaciens." Microorganisms 10, no. 8 (July 26, 2022): 1512. http://dx.doi.org/10.3390/microorganisms10081512.
Full textAbstract:
Volatile organic compounds (VOCs) emitted by bacteria play an important role in the interaction between microorganisms and other organisms. They can inhibit the growth of phytopathogenic microorganisms, modulate plant growth, and serve as infochemicals. Here, we investigated the effects of ketones, alcohols, and terpenes on the colony biofilms of plant pathogenic Agrobacterium tumefaciens strains and swimming motility, which can play an important role in the formation of biofilms. It was shown that 2-octanone had the greatest inhibitory effect on biofilm formation, acting in a small amount (38.7 g/m3). Ketone 2-butanone and unsaturated ketone β-ionone reduced the formation of biofilms at higher doses (145.2–580.6 and 387.1–1548.3 g/m3, respectively, up to 2.5–5 times). Isoamyl alcohol and 2-phenylethanol decreased the formation of biofilms at doses of 88.7 and 122.9 g/m3 by 1.7 and 5 times, respectively, with an increased effect at 177.4 and 245.9 g/m3, respectively. The agrobacteria cells in mature biofilms were more resistant to the action of ketones and alcohols. These VOCs also suppressed the swimming motility of agrobacteria; the radius of swimming zones decreased ~from 2 to 5 times. Terpenes (−)-limonene and (+)-α-pinene had no significant influence on the colony biofilms and swimming motility at the doses used. The results obtained represent new information about the effect of VOCs on biofilms and the motility of bacteria.
8
Scherr, Thomas, Chunliang Wu, W. Todd Monroe, and Krishnaswamy Nandakumar. "Computational fluid dynamics as a tool to understand the motility of microorganisms." Computers & Fluids 114 (July 2015): 274–83. http://dx.doi.org/10.1016/j.compfluid.2015.03.012.
Full text
9
Acres, Jacqueline, and Jay Nadeau. "2D vs 3D tracking in bacterial motility analysis." AIMS Biophysics 8, no. 4 (2021): 385–99. http://dx.doi.org/10.3934/biophy.2021030.
Full textAbstract:
<abstract> <p>Digital holographic microscopy provides the ability to observe throughout a large volume without refocusing. This capability enables simultaneous observations of large numbers of microorganisms swimming in an essentially unconstrained fashion. However, computational tools for tracking large 4D datasets remain lacking. In this paper, we examine the errors introduced by tracking bacterial motion as 2D projections vs. 3D volumes under different circumstances: bacteria free in liquid media and bacteria near a glass surface. We find that while XYZ speeds are generally equal to or larger than XY speeds, they are still within empirical uncertainties. Additionally, when studying dynamic surface behavior, the Z coordinate cannot be neglected.</p> </abstract>
10
Klimenko, A. I., and S. A. Lashin. "MODELING CHANGES IN THE ADAPTABILITY AND MOTILITY OF MICROORGANISMS IN CHANGING AQUATIC ECOSYSTEMS." http://eng.biomos.ru/conference/articles.htm 1, no. 19 (2021): 203–4. http://dx.doi.org/10.37747/2312-640x-2021-19-203-204.
Full textAbstract:
The results of our simulations show that motile forms (as opposed to sedentary forms) have an advantage under nutrient-poor conditions corresponding to the environment in which marine bacteria live. There is a turning point in the magnitude of the migration penalty that determines whether the Nomadic strategy will be successful or not.
11
Klimenko, Alexandra, Yury Matushkin, Nikolay Kolchanov, and Sergey Lashin. "Leave or Stay: Simulating Motility and Fitness of Microorganisms in Dynamic Aquatic Ecosystems." Biology 10, no. 10 (October 9, 2021): 1019. http://dx.doi.org/10.3390/biology10101019.
Full textAbstract:
Motility is a key adaptation factor in scarce marine environments inhabited by bacteria. The question of how a capacity for adaptive migrations influences the success of a microbial population in various conditions is a challenge addressed in this study. We employed the agent-based model of competition of motile and sedentary microbial populations in a confined aquatic environment supplied with a periodic batch nutrient source to assess the fitness of both. Such factors as nutrient concentration in a batch, batch period, mortality type and energetic costs of migration were considered to determine the conditions favouring different strategies: Nomad of a motile population and Settler of a sedentary one. The modelling results demonstrate that dynamic and nutrient-scarce environments favour motile populations, whereas nutrient-rich and stagnant environments promote sedentary microorganisms. Energetic costs of migration determine whether or not the Nomad strategy of the motile population is successful, though it also depends on such conditions as nutrient availability. Even without penalties for migration, under certain conditions, the sedentary Settler population dominates in the ecosystem. It is achieved by decreasing the local nutrient availability near the nutrient source, as motile populations relying on a local optimizing strategy tend to follow benign conditions and fail, enduring stress associated with crossing the valleys of suboptimal nutrient availability.
12
Martinez, Vincent A., Rut Besseling, Ottavio A. Croze, Julien Tailleur, Mathias Reufer, Jana Schwarz-Linek, Laurence G. Wilson, Martin A. Bees, and Wilson C. K. Poon. "Differential Dynamic Microscopy: A High-Throughput Method for Characterizing the Motility of Microorganisms." Biophysical Journal 103, no. 8 (October 2012): 1637–47. http://dx.doi.org/10.1016/j.bpj.2012.08.045.
Full text
13
Kloc, Malgorzata, Ahmed Uosef, Jacek Z. Kubiak, and Rafik M. Ghobrial. "Macrophage Proinflammatory Responses to Microorganisms and Transplanted Organs." International Journal of Molecular Sciences 21, no. 24 (December 18, 2020): 9669. http://dx.doi.org/10.3390/ijms21249669.
Full textAbstract:
Tissue-resident macrophages and those conscripted from the blood/bone marrow are professional phagocytes. They play a role in tissue homeostasis, replacement, and healing, and are the first-line responders to microbial (viral, bacterial, and fungi) infections. Intrinsic ameboid-type motility allows non-resident macrophages to move to the site of inflammation or injury, where, in response to the inflammatory milieu they perform the anti-microbial and/or tissue repair functions. Depending on the need and the signaling from the surrounding tissue and other immune cells, macrophages acquire morphologically and functionally different phenotypes, which allow them to play either pro-inflammatory or anti-inflammatory functions. As such, the macrophages are also the major players in the rejection of the transplanted organs making an excellent target for the novel anti-rejection therapies in clinical transplantation. In this review, we describe some of the less covered aspects of macrophage response to microbial infection and organ transplantation.
14
Conceição, Rita de Cássia dos Santos da, Régis Tuchtenhagen Sturbelle, Cláudio Dias Timm, and Fábio Pereira Leivas Leite. "Inducers and autoinducers on Salmonella enterica serovar Typhimurium motility, growth and gene expression." Ciência Rural 45, no. 12 (August 18, 2015): 2201–6. http://dx.doi.org/10.1590/0103-8478cr20150295.
Full textAbstract:
Genus Salmonella bacteria are among the major pathogenic microorganisms in food. This bacterium pathogenicity is related to a number of virulence factors, among which its flagella. Flagellum expression is one of the virulence factors modulated by Quorum Sensing. Epinephrine produced by mammals uses the same signaling pathway of the 3 bacteria autoinducer. This study evaluated the effect of molecules inducer (epinephrine) and autoinducers (autoinducer 2 and autoinducer 3) and their association with the motility, growth and expression genes flhC, fliA, fliY, motA, motB e fliC of Salmonella Typhimurium (ST). Initially, ST was inoculated in BHI. Then, motility assays, growth curves and gene expression were performed by testing different concentrations of epinephrine (50, 125, 250, 500µM), conditioned medium (10 and 50%) and a combination of these. ST was exposed to different concentrations of epinephrine, conditioned medium and an association of both. Following, motility assays, bacterial growth and gene expression were performed. The results obtained showed that the combination of 500uM epinephrine with 50% conditioned medium increased ST bacterial motility by increasing the expression of genes involved in flagellum assembly.
15
Quax, Tessa E. F., Sonja-Verena Albers, and Friedhelm Pfeiffer. "Taxis in archaea." Emerging Topics in Life Sciences 2, no. 4 (November 14, 2018): 535–46. http://dx.doi.org/10.1042/etls20180089.
Full textAbstract:
Microorganisms can move towards favorable growth conditions as a response to environmental stimuli. This process requires a motility structure and a system to direct the movement. For swimming motility, archaea employ a rotating filament, the archaellum. This archaea-specific structure is functionally equivalent, but structurally different, from the bacterial flagellum. To control the directionality of movement, some archaea make use of the chemotaxis system, which is used for the same purpose by bacteria. Over the past decades, chemotaxis has been studied in detail in several model bacteria. In contrast, archaeal chemotaxis is much less explored and largely restricted to analyses in halophilic archaea. In this review, we summarize the available information on archaeal taxis. We conclude that archaeal chemotaxis proteins function similarly as their bacterial counterparts. However, because the motility structures are fundamentally different, an archaea-specific docking mechanism is required, for which initial experimental data have only recently been obtained.
16
Goldberg, Marcia B. "Actin-Based Motility of Intracellular Microbial Pathogens." Microbiology and Molecular Biology Reviews 65, no. 4 (December 1, 2001): 595–626. http://dx.doi.org/10.1128/mmbr.65.4.595-626.2001.
Full textAbstract:
SUMMARY A diverse group of intracellular microorganisms, including Listeria monocytogenes, Shigella spp., Rickettsia spp., and vaccinia virus, utilize actin-based motility to move within and spread between mammalian host cells. These organisms have in common a pathogenic life cycle that involves a stage within the cytoplasm of mammalian host cells. Within the cytoplasm of host cells, these organisms activate components of the cellular actin assembly machinery to induce the formation of actin tails on the microbial surface. The assembly of these actin tails provides force that propels the organisms through the cell cytoplasm to the cell periphery or into adjacent cells. Each of these organisms utilizes preexisting mammalian pathways of actin rearrangement to induce its own actin-based motility. Particularly remarkable is that while all of these microbes use the same or overlapping pathways, each intercepts the pathway at a different step. In addition, the microbial molecules involved are each distinctly different from the others. Taken together, these observations suggest that each of these microbes separately and convergently evolved a mechanism to utilize the cellular actin assembly machinery. The current understanding of the molecular mechanisms of microbial actin-based motility is the subject of this review.
17
Berktas, Mustafa, Sabahattin Aydin, Yuksel Yilmaz, Kursat Cecen, and Hamza Bozkurt. "Sperm motility changes after coincubation with various uropathogenic microorganisms: an in vitro experimental study." International Urology and Nephrology 40, no. 2 (October 13, 2007): 383–89. http://dx.doi.org/10.1007/s11255-007-9289-4.
Full text
18
Breier, Rebekka E., Cristian C. Lalescu, Devin Waas, Michael Wilczek, and Marco G. Mazza. "Emergence of phytoplankton patchiness at small scales in mild turbulence." Proceedings of the National Academy of Sciences 115, no. 48 (November 8, 2018): 12112–17. http://dx.doi.org/10.1073/pnas.1808711115.
Full textAbstract:
Phytoplankton often encounter turbulence in their habitat. As most toxic phytoplankton species are motile, resolving the interplay of motility and turbulence has fundamental repercussions on our understanding of their own ecology and of the entire ecosystems they inhabit. The spatial distribution of motile phytoplankton cells exhibits patchiness at distances of decimeter to millimeter scales for numerous species with different motility strategies. The explanation of this general phenomenon remains challenging. Furthermore, hydrodynamic cell–cell interactions, which grow more relevant as the density in the patches increases, have been so far ignored. Here, we combine particle simulations and continuum theory to study the emergence of patchiness in motile microorganisms in three dimensions. By addressing the combined effects of motility, cell–cell interaction, and turbulent flow conditions, we uncover a general mechanism: The coupling of cell–cell interactions to the turbulent dynamics favors the formation of dense patches. Identification of the important length and time scales, independent from the motility mode, allows us to elucidate a general physical mechanism underpinning the emergence of patchiness. Our results shed light on the dynamical characteristics necessary for the formation of patchiness and complement current efforts to unravel planktonic ecological interactions.
19
Quax, Tessa E. F., Florian Altegoer, Fernando Rossi, Zhengqun Li, Marta Rodriguez-Franco, Florian Kraus, Gert Bange, and Sonja-Verena Albers. "Structure and function of the archaeal response regulator CheY." Proceedings of the National Academy of Sciences 115, no. 6 (January 22, 2018): E1259—E1268. http://dx.doi.org/10.1073/pnas.1716661115.
Full textAbstract:
Motility is a central feature of many microorganisms and provides an efficient strategy to respond to environmental changes. Bacteria and archaea have developed fundamentally different rotary motors enabling their motility, termed flagellum and archaellum, respectively. Bacterial motility along chemical gradients, called chemotaxis, critically relies on the response regulator CheY, which, when phosphorylated, inverses the rotational direction of the flagellum via a switch complex at the base of the motor. The structural difference between archaellum and flagellum and the presence of functional CheY in archaea raises the question of how the CheY protein changed to allow communication with the archaeal motility machinery. Here we show that archaeal CheY shares the overall structure and mechanism of magnesium-dependent phosphorylation with its bacterial counterpart. However, bacterial and archaeal CheY differ in the electrostatic potential of the helix α4. The helix α4 is important in bacteria for interaction with the flagellar switch complex, a structure that is absent in archaea. We demonstrated that phosphorylation-dependent activation, and conserved residues in the archaeal CheY helix α4, are important for interaction with the archaeal-specific adaptor protein CheF. This forms a bridge between the chemotaxis system and the archaeal motility machinery. Conclusively, archaeal CheY proteins conserved the central mechanistic features between bacteria and archaea, but differ in the helix α4 to allow binding to an archaellum-specific interaction partner.
20
Omori, Toshihiro, Hiroaki Ito, and Takuji Ishikawa. "Swimming microorganisms acquire optimal efficiency with multiple cilia." Proceedings of the National Academy of Sciences 117, no. 48 (November 16, 2020): 30201–7. http://dx.doi.org/10.1073/pnas.2011146117.
Full textAbstract:
Planktonic microorganisms are ubiquitous in water, and their population dynamics are essential for forecasting the behavior of global aquatic ecosystems. Their population dynamics are strongly affected by these organisms’ motility, which is generated by their hair-like organelles, called cilia or flagella. However, because of the complexity of ciliary dynamics, the precise role of ciliary flow in microbial life remains unclear. Here, we have used ciliary hydrodynamics to show that ciliates acquire the optimal propulsion efficiency. We found that ciliary flow highly resists an organism’s propulsion and that the swimming velocity rapidly decreases with body size, proportional to the power of minus two. Accordingly, the propulsion efficiency decreases as the cube of body length. By increasing the number of cilia, however, efficiency can be significantly improved, up to 100-fold. We found that there exists an optimal number density of cilia, which provides the maximum propulsion efficiency for all ciliates. The propulsion efficiency in this case decreases inversely proportionally to body length. Our estimated optimal density of cilia corresponds to those of actual microorganisms, including species of ciliates and microalgae, which suggests that now-existing motile ciliates and microalgae have survived by acquiring the optimal propulsion efficiency. These conclusions are helpful for better understanding the ecology of microorganisms, such as the energetic costs and benefits of multicellularity in Volvocaceae, as well as for the optimal design of artificial microswimmers.
21
Huwe, P., T. Diemer, M. Ludwig, J. Liu, H. G. Schiefer, and W. Weidner. "Influence of different uropathogenic microorganisms on human sperm motility parameters in an in vitro experiment." Andrologia 30, S1 (April 27, 2009): 55–59. http://dx.doi.org/10.1111/j.1439-0272.1998.tb02827.x.
Full text
22
Sisson, J. H. "Ethanol stimulates apparent nitric oxide-dependent ciliary beat frequency in bovine airway epithelial cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 268, no. 4 (April 1, 1995): L596—L600. http://dx.doi.org/10.1152/ajplung.1995.268.4.l596.
Full textAbstract:
The mucociliary apparatus of the lung provides an important host-defense function by clearing the upper airway of inhaled particles and infectious microorganisms. Because lung host defenses are impaired in alcoholics, we hypothesized that ethanol would decrease ciliary motility in airway epithelium. Ciliary beat frequency (CBF) was measured by videomicroscopy in primary cultures of ciliated bovine bronchial epithelial cells (BBECs). Ethanol rapidly stimulated ciliary motility in a time-dependent fashion with concentrations as low as 10 mM. No detectable decreases in ciliary motility were noted until ethanol concentrations exceeded 1,000 mM. Because many substances stimulate ciliary motility by releasing nitric oxide (NO) via upregulation of nitric oxide synthase (NOS), we preincubated ciliated BBECs with a stereospecific NOS inhibitor, NG-monomethyl-L-arginine (L-NMMA). L-NMMA completely blocked ethanol-induced stimulation of CBF, which could be subsequently restored by adding either L-arginine or sodium nitroprusside, which is a direct NO donor. These results indicate that ethanol, at clinically relevant concentrations, stimulates the release of NO by airway epithelium that upregulates ciliary motility. The rapidity of this response suggests upregulation of the constitutive NOS, known to be present in airway epithelium, and may explain the increases in mucociliary clearance observed in previous studies of ethanol ingestion in animals and in humans. These data also suggest a novel signal transduction pathway, the NO/NOS system, by which ethanol may exert some of its diverse biologic effects.
23
Nogales, Joaquina, Paola Vargas, Gabriela A. Farias, Adela Olmedilla, Juan Sanjuán, and María-Trinidad Gallegos. "FleQ Coordinates Flagellum-Dependent and -Independent Motilities in Pseudomonas syringae pv. tomato DC3000." Applied and Environmental Microbiology 81, no. 21 (August 21, 2015): 7533–45. http://dx.doi.org/10.1128/aem.01798-15.
Full textAbstract:
ABSTRACTMotility plays an essential role in bacterial fitness and colonization in the plant environment, since it favors nutrient acquisition and avoidance of toxic substances, successful competition with other microorganisms, the ability to locate the preferred hosts, access to optimal sites within them, and dispersal in the environment during the course of transmission. In this work, we have observed that the mutation of the flagellar master regulatory gene,fleQ, alters bacterial surface motility and biosurfactant production, uncovering a new type of motility forPseudomonas syringaepv. tomato DC3000 on semisolid surfaces. We present evidence thatP. syringaepv. tomato DC3000 moves over semisolid surfaces by using at least two different types of motility, namely, swarming, which depends on the presence of flagella and syringafactin, a biosurfactant produced by this strain, and a flagellum-independent surface spreading or sliding, which also requires syringafactin. We also show that FleQ activates flagellum synthesis and negatively regulates syringafactin production inP. syringaepv. tomato DC3000. Finally, it was surprising to observe that mutants lacking flagella or syringafactin were as virulent as the wild type, and only the simultaneous loss of both flagella and syringafactin impairs the ability ofP. syringaepv. tomato DC3000 to colonize tomato host plants and cause disease.
24
Zhou, Jian, Qian Ma, Hong Yi, Lili Wang, Hao Song, and Ying-Jin Yuan. "Metabolome Profiling Reveals Metabolic Cooperation between Bacillus megaterium and Ketogulonicigenium vulgare during Induced Swarm Motility." Applied and Environmental Microbiology 77, no. 19 (July 29, 2011): 7023–30. http://dx.doi.org/10.1128/aem.05123-11.
Full textAbstract:
ABSTRACTThe metabolic cooperation in the ecosystem ofBacillus megateriumandKetogulonicigenium vulgarewas investigated by cultivating them spatially on a soft agar plate. We found thatB. megateriumswarmed in a direction along the trace ofK. vulgareon the agar plate. Metabolomics based on gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF-MS) was employed to analyze the interaction mechanism between the two microorganisms. We found that the microorganisms interact by exchanging a number of metabolites. Both intracellular metabolism and cell-cell communication via metabolic cooperation were essential in determining the population dynamics of the ecosystem. The contents of amino acids and other nutritional compounds inK. vulgarewere rather low in comparison to those inB. megaterium, but the levels of these compounds in the medium surroundingK. vulgarewere fairly high, even higher than in fresh medium. Erythrose, erythritol, guanine, and inositol accumulated aroundB. megateriumwere consumed byK. vulgareupon its migration. The oxidization products ofK. vulgare, including 2-keto-gulonic acids (2KGA), were sharply increased. Upon coculturing ofB. megateriumandK. vulgare, 2,6-dipicolinic acid (the biomarker of sporulation ofB. megaterium), was remarkably increased compared with those in the monocultures. Therefore, the interactions betweenB. megateriumandK. vulgarewere a synergistic combination of mutualism and antagonism. This paper is the first to systematically identify a symbiotic interaction mechanism via metabolites in the ecosystem established by two isolated colonies ofB. megateriumandK. vulgare.
25
Mora, Maximilian, Annett Bellack, Matthias Ugele, Johann Hopf, and Reinhard Wirth. "The Temperature Gradient-Forming Device, an Accessory Unit for Normal Light Microscopes To Study the Biology of Hyperthermophilic Microorganisms." Applied and Environmental Microbiology 80, no. 15 (May 23, 2014): 4764–70. http://dx.doi.org/10.1128/aem.00984-14.
Full textAbstract:
ABSTRACTTo date, the behavior of hyperthermophilic microorganisms in their biotope has been studied only to a limited degree; this is especially true for motility. One reason for this lack of knowledge is the requirement for high-temperature microscopy—combined, in most cases, with the need for observations under strictly anaerobic conditions—for such studies. We have developed a custom-made, low-budget device that, for the first time, allows analyses in temperature gradients up to 40°C over a distance of just 2 cm (a biotope-relevant distance) with heating rates up to ∼5°C/s. Our temperature gradient-forming device can convert any upright light microscope into one that works at temperatures as high as 110°C. Data obtained by use of this apparatus show how very well hyperthermophiles are adapted to their biotope: they can react within seconds to elevated temperatures by starting motility—even after 9 months of storage in the cold. Using the temperature gradient-forming device, we determined the temperature ranges for swimming, and the swimming speeds, of 15 selected species of the genusThermococcuswithin a few months, related these findings to the presence of cell surface appendages, and obtained the first evidence for thermotaxis inArchaea.
26
Brown, Igor I., and Claudia C. Häse. "Flagellum-Independent Surface Migration ofVibrio cholerae and Escherichia coli." Journal of Bacteriology 183, no. 12 (June 15, 2001): 3784–90. http://dx.doi.org/10.1128/jb.183.12.3784-3790.2001.
Full textAbstract:
ABSTRACT Surface translocation has been described in a large variety of microorganisms, including some gram-negative enteric bacteria. Here, we describe the novel observation of the flagellum-independent migration of Vibrio cholerae and Escherichia coli on semisolid surfaces with remarkable speeds. Important aspects of this motility are the form of inoculation, the medium composition, and the use of agarose rather than agar. Mutations in several known regulatory or surface structure proteins, such as ToxR, ToxT, TCP, and PilA, did not affect migration, whereas a defect in lipopolysaccharide biosynthesis prevented translocation. We propose that the observed surface migration is an active process, since heat, protease, or chloramphenicol treatments of the cells have strong negative effects on this phenotype. Furthermore, several V. cholerae strains strongly expressing the hemagglutinin/protease but not their isogenichap-negative mutants, lacked the ability of surface motility, and the treatment of migrating strains with culture supernatants from hap strains but not hap-null strains prevented surface translocation.
27
Lee, Yunna, Jeongbin Jo, Hae Young Chung, Charalabos Pothoulakis, and Eunok Im. "Endocannabinoids in the gastrointestinal tract." American Journal of Physiology-Gastrointestinal and Liver Physiology 311, no. 4 (October 1, 2016): G655—G666. http://dx.doi.org/10.1152/ajpgi.00294.2015.
Full textAbstract:
The endocannabinoid system mainly consists of endogenously produced cannabinoids (endocannabinoids) and two G protein-coupled receptors (GPCRs), cannabinoid receptors 1 and 2 (CB1 and CB2). This system also includes enzymes responsible for the synthesis and degradation of endocannabinoids and molecules required for the uptake and transport of endocannabinoids. In addition, endocannabinoid-related lipid mediators and other putative endocannabinoid receptors, such as transient receptor potential channels and other GPCRs, have been identified. Accumulating evidence indicates that the endocannabinoid system is a key modulator of gastrointestinal physiology, influencing satiety, emesis, immune function, mucosal integrity, motility, secretion, and visceral sensation. In light of therapeutic benefits of herbal and synthetic cannabinoids, the vast potential of the endocannabinoid system for the treatment of gastrointestinal diseases has been demonstrated. This review focuses on the role of the endocannabinoid system in gut homeostasis and in the pathogenesis of intestinal disorders associated with intestinal motility, inflammation, and cancer. Finally, links between gut microorganisms and the endocannabinoid system are briefly discussed.
28
Ning, Zhenzhen, Bei Xue, and Huhu Wang. "Evaluation of the Adhesive Potential of Bacteria Isolated from Meat-Related Sources." Applied Sciences 11, no. 22 (November 12, 2021): 10652. http://dx.doi.org/10.3390/app112210652.
Full textAbstract:
Microbial adhesion constitutes the transition of microorganisms from a planktonic mode to a static one. It promotes the formation of biofilm which is responsible for spoilage, foodborne diseases, and corrosion in the food processing industry. In this study, the adhesive potential of fourteen meat-borne bacterial isolates belonging to seven different genera was investigated. All strains were found able to colonize polystyrene surfaces with different levels of firmness. Significant variations were determined in assays of bacterial hydrophobicity and motility. Among the 14 strains, Pseudomonas fragi, Aeromonas salmonicida II, Serratia liquefaciens, Citrobacter braakii, Pseudomonas putida, and Aeromonas veronii had a strong hydrophobic force, while the isolates of Lactobacillus genus showed the most hydrophilic property. In terms of motility, Citrobacter braakii and Escherichia coli exhibited exceptional swarming and swimming abilities, whilst conservatively weak performances were observed in the Lactobacillus strains. Furthermore, the majority of the isolates were predominantly electron donors and weak electron acceptors. Overall, a high level of correlation was observed between biofilm-forming ability with cell surface hydrophobicity and Lewis acid–base properties, whereas the contribution of motility in bacterial adhesion could not be confirmed. Research on the adhesive performance of foodborne bacteria is potentially conducive to developing novel control strategies, such as food processing equipment with specific surfaces, not facilitating attachment.
29
Ni, Bin, Remy Colin, Hannes Link, Robert G. Endres, and Victor Sourjik. "Growth-rate dependent resource investment in bacterial motile behavior quantitatively follows potential benefit of chemotaxis." Proceedings of the National Academy of Sciences 117, no. 1 (December 23, 2019): 595–601. http://dx.doi.org/10.1073/pnas.1910849117.
Full textAbstract:
Microorganisms possess diverse mechanisms to regulate investment into individual cellular processes according to their environment. How these regulatory strategies reflect the inherent trade-off between the benefit and cost of resource investment remains largely unknown, particularly for many cellular functions that are not immediately related to growth. Here, we investigate regulation of motility and chemotaxis, one of the most complex and costly bacterial behaviors, as a function of bacterial growth rate. We show with experiment and theory that in poor nutritional conditions,Escherichia coliincreases its investment in motility in proportion to the reproductive fitness advantage provided by the ability to follow nutrient gradients. Since this growth-rate dependent regulation of motility genes occurs even when nutrient gradients are absent, we hypothesize that it reflects an anticipatory preallocation of cellular resources. Notably, relative fitness benefit of chemotaxis could be observed not only in the presence of imposed gradients of secondary nutrients but also in initially homogeneous bacterial cultures, suggesting that bacteria can generate local gradients of carbon sources and excreted metabolites, and subsequently use chemotaxis to enhance the utilization of these compounds. This interplay between metabolite excretion and their chemotaxis-dependent reutilization is likely to play an important general role in microbial communities.
30
Oura, Hiromu, Yosuke Tashiro, Masanori Toyofuku, Kousetsu Ueda, Tatsunori Kiyokawa, Satoshi Ito, Yurika Takahashi, et al. "Inhibition of Pseudomonas aeruginosa Swarming Motility by 1-Naphthol and Other Bicyclic Compounds Bearing Hydroxyl Groups." Applied and Environmental Microbiology 81, no. 8 (February 13, 2015): 2808–18. http://dx.doi.org/10.1128/aem.04220-14.
Full textAbstract:
ABSTRACTMany bacteria convert bicyclic compounds, such as indole and naphthalene, to oxidized compounds, including hydroxyindoles and naphthols.Pseudomonas aeruginosa, a ubiquitous bacterium that inhabits diverse environments, shows pathogenicity against animals, plants, and other microorganisms, and increasing evidence has shown that several bicyclic compounds alter the virulence-related phenotypes ofP. aeruginosa. Here, we revealed that hydroxyindoles (4- and 5-hydroxyindoles) and naphthalene derivatives bearing hydroxyl groups specifically inhibit swarming motility but have minor effects on other motilities, including swimming and twitching, inP. aeruginosa. Further analyses using 1-naphthol showed that this effect is also associated with clinically isolated hyperswarmingP. aeruginosacells. Swarming motility is associated with the dispersion of cells from biofilms, and the addition of 1-naphthol maintained biofilm biomass without cell dispersion. We showed that this 1-naphthol-dependent swarming inhibition is independent of changes of rhamnolipid production and the intracellular level of signaling molecule cyclic-di-GMP (c-di-GMP). Transcriptome analyses revealed that 1-naphthol increases gene expression associated with multidrug efflux and represses gene expression associated with aerotaxis and with pyochelin, flagellar, and pilus synthesis. In the present study, we showed that several bicyclic compounds bearing hydroxyl groups inhibit the swarming motility ofP. aeruginosa, and these results provide new insight into the chemical structures that inhibit the specific phenotypes ofP. aeruginosa.
31
Nugraheni, Irma Prasety Ayu, Derana Widyastika, Sofia Maulida, Heni Susilowati, and Alma Linggar Jonarta. "Effect of Red Onion (Allium cepa var ascalonicum) Skin Ethanolic Extract on the Motility and the Adhesion Index of Pseudomonas aeruginosa and Macrophage Phagocytosis Index." Majalah Obat Tradisional 24, no. 1 (April 30, 2019): 40. http://dx.doi.org/10.22146/mot.45532.
Full textAbstract:
Red onion skin (Allium cepa var ascalonicum) contains various ingredients that may function as antibacterial agents against microorganisms, as well as anti-inflammatory and immunomodulator agents for host cells, such as macrophages. Pseudomonas aeruginosa found in the oral cavity is commensal bacteria that may turn into opportunistic pathogen by utilizing its virulence factors such as motility and adhesion to the host cell. The purpose of this study was to investigate the effect of red-onion-skin ethanolic extract towards P. aeruginosa ATCC 9027 on the motility and adhesion ability, furthermore, to know its effect on the macrophage phagocytosis. The research was conducted into three parts of experiment using red-onion-skin ethanolic extract. Extract-induced bacterial motility test was carried out on semi-solid media, stained using 0.1% crystal violet, then the radial length of the bacterial movement was measured. The bacterial adhesion index to buccal cells was calculated after incubated for two hours and stained with Gram stain. Phagocytic activity of the host cells on P. aeruginosa was done by exposing the extract to the mouse peritoneal macrophages, then the phagocytosed bacteria were counted after Giemsa staining. Statistical test results from the three experiments showed significant differences between the test groups compared to the control groups (p <0.05). It was concluded that the red onion-skin ethanolic extract not only affects P. aeruginosa by reducing swarming motility and preventing bacterial adhesion to buccal epithelial cells, but also induces the host cells by increasing the ability of macrophage phagocytosis to these bacteria.
32
Palacci, Jérémie, Stefano Sacanna, Anaïs Abramian, Jérémie Barral, Kasey Hanson, Alexander Y. Grosberg, David J. Pine, and Paul M. Chaikin. "Artificial rheotaxis." Science Advances 1, no. 4 (May 2015): e1400214. http://dx.doi.org/10.1126/sciadv.1400214.
Full textAbstract:
Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes.
33
Abbamondi, Gennaro Roberto, and Giuseppina Tommonaro. "Research Progress and Hopeful Strategies of Application of Quorum Sensing in Food, Agriculture and Nanomedicine." Microorganisms 10, no. 6 (June 10, 2022): 1192. http://dx.doi.org/10.3390/microorganisms10061192.
Full textAbstract:
Quorum sensing (QS) regulates the expression of several genes including motility, biofilm development, virulence expression, population density detection and plasmid conjugation. It is based on “autoinducers”, small molecules that microorganisms produce and release in the extracellular milieu. The biochemistry of quorum sensing is widely discussed and numerous papers are available to scientists. The main purpose of this research is to understand how knowledge about this mechanism can be exploited for the benefit of humans and the environment. Here, we report the most promising studies on QS and their resulting applications in different fields of global interest: food, agriculture and nanomedicine.
34
Ménard, Robert, Ian C. Schoenhofen, Limei Tao, Annie Aubry, Patrice Bouchard, Christopher W. Reid, Paule Lachance, et al. "Small-Molecule Inhibitors of the Pseudaminic Acid Biosynthetic Pathway: Targeting Motility as a Key Bacterial Virulence Factor." Antimicrobial Agents and Chemotherapy 58, no. 12 (September 29, 2014): 7430–40. http://dx.doi.org/10.1128/aac.03858-14.
Full textAbstract:
ABSTRACTHelicobacter pyloriis motile by means of polar flagella, and this motility has been shown to play a critical role in pathogenicity. The major structural flagellin proteins have been shown to be glycosylated with the nonulosonate sugar, pseudaminic acid (Pse). This glycan is unique to microorganisms, and the process of flagellin glycosylation is required forH. pyloriflagellar assembly and consequent motility. As such, the Pse biosynthetic pathway offers considerable potential as an antivirulence drug target, especially since motility is required forH. pyloricolonization and persistence in the host. This report describes screening the five Pse biosynthetic enzymes for small-molecule inhibitors using both high-throughput screening (HTS) andin silico(virtual screening [VS]) approaches. Using a 100,000-compound library, 1,773 hits that exhibited a 40% threshold inhibition at a 10 μM concentration were identified by HTS. In addition, VS efforts using a 1.6-million compound library directed at two pathway enzymes identified 80 hits, 4 of which exhibited reasonable inhibition at a 10 μM concentrationin vitro. Further secondary screening which identified 320 unique molecular structures or validated hits was performed. Following kinetic studies and structure-activity relationship (SAR) analysis of selected inhibitors from our refined list of 320 compounds, we demonstrated that three inhibitors with 50% inhibitory concentrations (IC50s) of approximately 14 μM, which belonged to a distinct chemical cluster, were able to penetrate the Gram-negative cell membrane and prevent formation of flagella.
35
Ahmed, E., MS Islam, MGS Alam, PK Jha, S. Ghosh, N. Naher, and FY Bari. "Bacterial contamination of ram semen used for artificial insemination in indigenous ewes." Bangladesh Veterinarian 34, no. 1 (October 28, 2018): 20–26. http://dx.doi.org/10.3329/bvet.v34i1.38709.
Full textAbstract:
Ram semen was assessed for quality and presence of bacteria. Four ejaculates were collected from each of four rams twice a week using artificial vagina. The volume varied from 0.4 - 1.3 mL, colour from 2 - 4 (creamy to creamy-grey), mass activity from 3 - 5, sperm motility from 75 - 85%, viability from 80 - 95%, and concentration from, 2500 - 5000 × 106/mL. The mass activity of ram R6 was significantly (P<0.05) higher (5.0 ± 0.0) compared with ram R1 (4.4 ± 0.5), R2 (3.9 ± 0.0) and R5 (4.7 ± 0.5). The mean motility was 81.7 ± 4.0, viability 90.0 ± 4.0 and concentration 3519.0 ± 545.6 x 106/ml. E. coli and Staphylococcus spp. were found in all four rams’ fresh semen confirmed by culture, staining and biochemical tests. However, Bacillus spp. was found only in ram R5. When the semen samples were treated with antibiotics there was no growth of bacteria after three days of incubation. It is suggested antibiotics control the transmission of microorganisms through AI in ewes.Bangl. vet. 2017. Vol. 34, No. 1, 20-26
36
Burbank, Lindsey, Mojtaba Mohammadi, and M. Caroline Roper. "Siderophore-Mediated Iron Acquisition Influences Motility and Is Required for Full Virulence of the Xylem-Dwelling Bacterial Phytopathogen Pantoea stewartii subsp. stewartii." Applied and Environmental Microbiology 81, no. 1 (October 17, 2014): 139–48. http://dx.doi.org/10.1128/aem.02503-14.
Full textAbstract:
ABSTRACTIron is a key micronutrient for microbial growth but is often present in low concentrations or in biologically unavailable forms. Many microorganisms overcome this challenge by producing siderophores, which are ferric-iron chelating compounds that enable the solubilization and acquisition of iron in a bioactive form.Pantoeastewartiisubsp.stewartii, the causal agent of Stewart's wilt of sweet corn, produces a siderophore under iron-limiting conditions. The proteins involved in the biosynthesis and export of this siderophore are encoded by theiucABCD-iutAoperon, which is homologous to the aerobactin biosynthetic gene cluster found in a number of enteric pathogens. Mutations iniucAandiutAresulted in a decrease in surface-based motility thatP. stewartiiutilizes during the early stages of biofilm formation, indicating that active iron acquisition impacts surface motility forP. stewartii. Furthermore, bacterial movementin plantais also dependent on a functional siderophore biosynthesis and uptake pathway. Most notably, siderophore-mediated iron acquisition is required for full virulence in the sweet corn host, indicating that active iron acquisition is essential for pathogenic fitness for this important xylem-dwelling bacterial pathogen.
37
Rajasekharan, Satish Kumar, and Moshe Shemesh. "The Bacillary Postbiotics, Including 2-Undecanone, Suppress the Virulence of Pathogenic Microorganisms." Pharmaceutics 14, no. 5 (April 29, 2022): 962. http://dx.doi.org/10.3390/pharmaceutics14050962.
Full textAbstract:
Secreted molecules from probiotic Bacilli have often been considered potential pharmaceuticals to fight infections caused by bacterial or yeast pathogens. In the present study, we investigated the antagonistic potential of secreted probiotic filtrates (hereafter, postbiotics) derived from Lactobacillus plantarum cells against pathogenic microorganisms, such as Escherichia coli, Staphylococcus aureus, and Candida albicans. We found that the postbiotics mitigate the biofilms of the tested pathogens with no notable effect on their planktonic growth. In addition, the postbiotics suppressed some virulence traits, for instance, the dendrite swarming motility of E. coli and yeast-to-hyphal switch in C. albicans. Further assays with an active constituent produced by the L. plantarum cells–2-undecanone revealed two significant findings: (i) 2-undecanone inhibits C. albicans biofilms and hyphae in vitro and in a Caenorhabditis elegans model, and (ii) it interacts specifically with Gln 58 amino acid residue of hyphal wall protein-1 (Hwp-1) in molecular docking analysis. The results suggest the targeted mode of antagonistic action of 2-undecanone against C. albicans biofilm. In total, the findings of the study depict an appealing strategy to use postbiotics, including specific ketone molecules, produced by L. plantarum for developing novel antibiofilm and anti-hyphal pharmaceuticals.
38
Behkam, Bahareh, and Metin Sitti. "Design Methodology for Biomimetic Propulsion of Miniature Swimming Robots." Journal of Dynamic Systems, Measurement, and Control 128, no. 1 (September 23, 2005): 36–43. http://dx.doi.org/10.1115/1.2171439.
Full textAbstract:
Miniature and energy-efficient propulsion systems hold the key to maturing the technology of swimming microrobots. In this paper, two new methods of propulsion inspired by the motility mechanism of prokaryotic and eukaryotic microorganisms are proposed. Hydrodynamic models for each of the two methods are developed, and the optimized design parameters for each of the two propulsion modes are demonstrated. To validate the theoretical result for the prokaryotic flagellar motion, a scaled-up prototype of the robot is fabricated and tested in silicone oil, using the Buckingham PI theorem for scaling. The proposed propulsion methods are appropriate for the swimming robots that are intended to swim in low-velocity fluids.
39
Rennemeier, Claudia, Torsten Frambach, Florian Hennicke, Johannes Dietl, and Peter Staib. "Microbial Quorum-Sensing Molecules Induce Acrosome Loss and Cell Death in Human Spermatozoa." Infection and Immunity 77, no. 11 (August 17, 2009): 4990–97. http://dx.doi.org/10.1128/iai.00586-09.
Full textAbstract:
ABSTRACT Infertility in men and women is frequently associated with genital contamination by various commensal or uropathogenic microbes. Since many microorganisms are known to release quorum-sensing signals in substantial amounts, we raised the question whether such molecules can directly affect human spermatozoa. Here we show that farnesol and 3-oxododecanoyl-l-homoserine lactone, employed by the opportunistic pathogenic yeast Candida albicans and the gram-negative bacterium Pseudomonas aeruginosa, respectively, induce multiple damage in spermatozoa. A reduction in the motility of spermatozoa coincided in a dose-dependent manner with apoptosis and necrosis at concentrations which were nondeleterious for dendritic cell-like immune cells. Moreover, sublethal doses of both signaling molecules induced premature loss of the acrosome, a cap-like structure of the sperm head which is essential for fertilization. Addressing their mechanism of action, we found that the bacterial molecule, but not the fungal molecule, actively induced the acrosome reaction via a calcium-dependent mechanism. This work uncovers a new facet in the interaction of microorganisms with human gametes and suggests a putative link between microbial communication systems and host infertility.
40
Abdelwahed, Eman K., Nahla A. Hussein, Ahmed Moustafa, Nayera A. Moneib, and Ramy K. Aziz. "Gene Networks and Pathways Involved in Escherichia coli Response to Multiple Stressors." Microorganisms 10, no. 9 (September 6, 2022): 1793. http://dx.doi.org/10.3390/microorganisms10091793.
Full textAbstract:
Stress response helps microorganisms survive extreme environmental conditions and host immunity, making them more virulent or drug resistant. Although both reductionist approaches investigating specific genes and systems approaches analyzing individual stress conditions are being used, less is known about gene networks involved in multiple stress responses. Here, using a systems biology approach, we mined hundreds of transcriptomic data sets for key genes and pathways involved in the tolerance of the model microorganism Escherichia coli to multiple stressors. Specifically, we investigated the E. coli K-12 MG1655 transcriptome under five stresses: heat, cold, oxidative stress, nitrosative stress, and antibiotic treatment. Overlaps of transcriptional changes between studies of each stress factor and between different stressors were determined: energy-requiring metabolic pathways, transport, and motility are typically downregulated to conserve energy, while genes related to survival, bona fide stress response, biofilm formation, and DNA repair are mainly upregulated. The transcription of 15 genes with uncharacterized functions is higher in response to multiple stressors, which suggests they may play pivotal roles in stress response. In conclusion, using rank normalization of transcriptomic data, we identified a set of E. coli stress response genes and pathways, which could be potential targets to overcome antibiotic tolerance or multidrug resistance.
41
Santajit, Sirijan, Nitat Sookrung, and Nitaya Indrawattana. "Quorum Sensing in ESKAPE Bugs: A Target for Combating Antimicrobial Resistance and Bacterial Virulence." Biology 11, no. 10 (October 6, 2022): 1466. http://dx.doi.org/10.3390/biology11101466.
Full textAbstract:
A clique of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) bugs is the utmost causative agent responsible for multidrug resistance in hospital settings. These microorganisms employ a type of cell–cell communication termed ‘quorum sensing (QS) system’ to mediate population density and synchronously control the genes that modulate drug resistance and pathogenic behaviors. In this article, we focused on the present understanding of the prevailing QS system in ESKAPE pathogens. Basically, the QS component consisted of an autoinducer synthase, a ligand (e.g., acyl homoserine lactones/peptide hormones), and a transcriptional regulator. QS mediated expression of the bacterial capsule, iron acquisition, adherence factors, synthesis of lipopolysaccharide, poly-N-acetylglucosamine (PNAG) biosynthesis, motility, as well as biofilm development allow bacteria to promote an antimicrobial-resistant population that can escape the action of traditional drugs and endorse a divergent virulence production. The increasing prevalence of these harmful threats to infection control, as well as the urgent need for effective antimicrobial strategies to combat them, serve to highlight the important anti-QS strategies developed to address the difficulty of treating microorganisms.
42
Yang, Jianjun, Wenjing Li, Dexiong Teng, Xiaodong Yang, Yijun Zhang, and Yan Li. "Metagenomic Insights into Microbial Community Structure, Function, and Salt Adaptation in Saline Soils of Arid Land, China." Microorganisms 10, no. 11 (November 3, 2022): 2183. http://dx.doi.org/10.3390/microorganisms10112183.
Full textAbstract:
Soil salinization is spread in the dryland of NW China due to the dry or extreme dry climate. Increased salinization damages the health and function of soil systems and influences the microbial community structure and function. Some studies have been conducted to reveal the microbial community structure and isolate the microorganisms of saline soil or salt-lake sediments in this region. However, the functions of microorganisms and their response to salinization, i.e., their adaptation strategy to a wide salinization range in arid environments, are less understood. Here, we applied metagenomics technology to investigate the microbial community structure, function, and their relationship with salinization, and discussed the adaptative strategy of microorganisms to different saline environments. A total of 42 samples were sequenced on the Illumina PE500 platform. The archaea and bacteria constituted the dominant kingdoms; Actinobacteria, Proteobacteria, Bacteroidetes, and Firmicutes were the dominant bacterial phyla; and Euryarchaeota were the dominant archaeal phylum. The microbial communities showed significant structure divergence according to the salt concentration (saline (mean EC 22 mS/cm) and hypersaline (mean EC 70 mS/cm)), wherein the communities were dominated by bacteria in saline soils and archaea in hypersaline soils. Most of the dominant bacterial representation decreased with salinity, while the archaea increased with salinity. KEGG functional annotation showed that at level 2, the cell motility, environmental adaptation, signal transduction, signaling molecules and interaction, glycan biosynthesis and metabolism, and metabolism of other amino acids were reduced from saline to hypersaline, whereas the metabolism of cofactors and vitamins, folding sorting and degradation, replication and repair, transcription and translation, amino acid biosynthesis, glycolysis/gluconeogenesis, and carbon fixation increased with salinity. The increased salt content decreased the carbohydrate activities of microorganisms. The osmolyte regulation substance synthesis and absorption-related genes were more abundant in saline soils than in hypersaline soils, whereas the Na+/H+ antiporter genes (mnhB-E) and H+/Na+-transporting ATPase genes (atpA-F, I, K) were significantly higher in hypersaline soils. This indicated that in saline soils, microorganisms primarily synthesize and/or uptake compatible solutes to cope with osmotic stress, whereas in the hypersaline habitat, the high-salt-in strategy was predicated to be adopted by the halophilic/extremely halophilic microorganisms, coupled with a high abundance of replication and repair, cofactors and vitamin metabolism, nucleotide metabolism, and carbon fixation to provide energy and ensure cell regeneration. In conclusion, increases in salinity influence the microbial communities’ structure and function, as well as the adaptation of microorganisms.
43
Tsyganov, I. V., and A. G. Tkachenko. "Effect of biogenic polyamines on sliding motility of mycobacteria in the presence of antibiotics." Vavilov Journal of Genetics and Breeding 26, no. 5 (September 3, 2022): 458–66. http://dx.doi.org/10.18699/vjgb-22-56.
Full textAbstract:
Nowadays, sliding is the least investigated mode of bacterial motility. Sliding is a process of passive movement on the surface of semi-liquid mediums which was originally described for mycobacteria and other bacterial species deprived of the organelles specialized for movement. Some mycobacteria are able to colonize surfaces, including tissues of macro-organisms, using glycopeptidolipids localized in the cell envelope for this aim. This is a serious problem for effective therapy of mycobacteriosis caused by nontuberculosis mycobacteria. Furthermore, animal tissues contain biogenic polyamines, which can increase tolerance of microorganisms to stresses, including antibiotics, and modulate cell motility. Therefore, studying mutual effects of biogenic polyamines and antibiotics on the expansion of mycobacteria is important for medicine. Mycobacterial strains, including the parent Mycolicibacterium smegmatis mc2 155 and strains containing single (ΔrelMsm) or double (ΔrelMsmΔrelZ) deletions, were used as the objects of this study. The content of glycopeptidolipids was determined using thin layer chromatography. Sliding motility was assessed by measuring the area of the sliding colony. The effectiveness of antibiotics was measured by comparison of the areas of sliding colonies in the presence of comparable concentrations of antibiotics. The polyamines spermidine and spermine had different effects on the sliding of mycobacteria through an increase or decrease in the colony areas. At the same time, polyamines had neither bactericidal nor bacteriostatic effects. The polyamines contained in the medium decreased the bactericidal effects of the antibiotics streptomycin or isoniazid, but enhanced the effects of DMNP, a synthetic analogue of the natural antibiotic erogorgiaene. Rifampicin was the most effective of all antibiotics investigated here. Moreover, we found that glycopeptidolipids are, apparently, not the only regulators of mycobacterial sliding.
44
Akter, Tahmina, Mansura Mokbul, Susmita Ghosh, and Moumita Dey. "Raw Milk in Noakhlai, Bangladesh: Quality Assessment and Antibiotic Resistance of Identified Microorganisms." Current Research in Nutrition and Food Science Journal 9, no. 3 (December 30, 2021): 1104–12. http://dx.doi.org/10.12944/crnfsj.9.3.35.
Full textAbstract:
Milk is an ideal food for all age groups. The current study was carried out to identify the microorganisms to assess the raw milk quality and the antibiotic resistance of those identified micro-organisms. Five raw milk samples along with two high treatment (UHT) milk samples from different locations of Noakhali district of Bangladesh were analysed. Bacterial isolation was performed by Nutrient Agar (NA) and MacConkey (MCA), Eiosin Methylene Blue (EMB) and Genital menital salt agar (GMSA). The isolates were then identified by Kliger’s Iron Agar (KIA) test, Motility Indole Urease (MIU) test, Catalase and Oxidase tests. Antibiotics resistance tests were done for 13 different antibiotics. Among all these samples, Maijdee Bazar (S4) contained the highest load as 1.87×106 and the UHT samples contained no bacterial contamination. E. coli covered 47.05% whereas Listeria, Bacillus and Yersinia were in the same percentage as 5.88% among all isolates. Salmonella and Staphylococcus were 23.53% and 11.76%, respectively. Listeria and Salmonella were resistant to five different antibiotics by 46.15% and 38.46% of multiple antibiotic resistance index (MRI), correspondingly. However, E. coli and Yersinia were resistant to three antibiotics namely, Rifampcin (RIF), Cefotaxime (CTX), Amoxycillin (AMX) by about 23% as MRI percentage. Bacillus and Staphylococcus both were resistant to Cefepime (CPM) by 7.69% of MRI. Hence, it can be concluded that Rifampcin and Cefepime were most common antibiotics which were resisted by most of the isolates. Therefore, hygiene aspect of these milk sources needs to be taken into consideration with high priority. Also, the antibiotics which are resisted by different organisms will be detrimental for public health aspects.
45
Ige, Ebenezer Olubunmi, Isaac Folorunso Odesola, Sikiru Babatunde Ayedun, and Olusegun M. Ilori. "Magneto-Rotational Augmentation of Bioconvective Transport in Plasma-Nanofluid Flowing through a Penetrable Spinning Disc." Journal of Engineering 2022 (November 30, 2022): 1–24. http://dx.doi.org/10.1155/2022/3499192.
Full textAbstract:
The phenomenon of bioconvective transport through the manipulation of motile microorganisms is considered a promising process control technique in several biological processes and microdevices. Inducing convective transport in self-propelling microbes could be tailored to improve mixing, reaction propensity, and concentration transport within the media. This paper examined the combined effect of magnetic and rotational fields on the argumentation of bioconvective transport in the nanofluid-mediated plasma flow. A detailed analysis of the transport and dynamics of reactive forces during bioconvection in a rotary disc-like microchannel is presented. The physics of the problem was described by coupled nonlinear ordinary differential equations, which were numerically computed using the spectral relaxation scheme of the spectral homotopy analysis method. It was observed that the imposition of a magnetic field constituted viscous drag in the plasma-nanofluid media, which consequently increases the thermophoretic parameter in the bioconvective flow. It was ascertained that coupled magnetic and rotational effects significantly augmented the motility of microorganisms and translated to growth in momentum and concentration fields which is noticeable in the generation of stretching effect on the bacterium-containing plasma-nanofluid flow. The findings of this study could provide an essential basis for the design of bioreactors, centrifugal microfluidics technologies, and microdevices for use in a broad spectrum of biotechnology.
46
McCoy, Andrea J., Hongjian Liu, Timothy J. Falla, and John S. Gunn. "Identification of Proteus mirabilisMutants with Increased Sensitivity to Antimicrobial Peptides." Antimicrobial Agents and Chemotherapy 45, no. 7 (July 1, 2001): 2030–37. http://dx.doi.org/10.1128/aac.45.7.2030-2037.2001.
Full textAbstract:
ABSTRACT Antimicrobial peptides (APs) are important components of the innate defenses of animals, plants, and microorganisms. However, some bacterial pathogens are resistant to the action of APs. For example,Proteus mirabilis is highly resistant to the action of APs, such as polymyxin B (PM), protegrin, and the synthetic protegrin analog IB-367. To better understand this resistance, a transposon mutagenesis approach was used to generate P. mirabilismutants sensitive to APs. Four unique PM-sensitive mutants of P. mirabilis were identified (these mutants were >2 to >128 times more sensitive than the wild type). Two of these mutants were also sensitive to IB-367 (16 and 128 times more sensitive than the wild type). Lipopolysaccharide (LPS) profiles of the PM- and protegrin-sensitive mutants demonstrated marked differences in both the lipid A and O-antigen regions, while the PM-sensitive mutants appeared to have alterations of either lipid A or O antigen. Matrix-assisted laser desorption ionization–time of flight mass spectrometry analysis of the wild-type and PM-sensitive mutant lipid A showed species with one or two aminoarabinose groups, while lipid A from the PM- and protegrin-sensitive mutants was devoid of aminoarabinose. When the mutants were streaked on an agar-containing medium, the swarming motility of the PM- and protegrin-sensitive mutants was completely inhibited and the swarming motility of the mutants sensitive to only PM was markedly decreased. DNA sequence analysis of the mutagenized loci revealed similarities to an O-acetyltransferase (PM and protegrin sensitive) and ATP synthase and sap loci (PM sensitive). These data further support the role of LPS modifications as an elaborate mechanism in the resistance of certain bacterial species to APs and suggest that LPS surface charge alterations may play a role in P. mirabilis swarming motility.
47
Markus, Victor, Orr Share, Marilou Shagan, Barak Halpern, Tal Bar, Esti Kramarsky-Winter, Kerem Teralı, et al. "Inhibitory Effects of Artificial Sweeteners on Bacterial Quorum Sensing." International Journal of Molecular Sciences 22, no. 18 (September 13, 2021): 9863. http://dx.doi.org/10.3390/ijms22189863.
Full textAbstract:
Despite having been tagged as safe and beneficial, recent evidence remains inconclusive regarding the status of artificial sweeteners and their putative effects on gut microbiota. Gut microorganisms are essential for the normal metabolic functions of their host. These microorganisms communicate within their community and regulate group behaviors via a molecular system termed quorum sensing (QS). In the present study, we aimed to study the effects of artificial sweeteners on this bacterial communication system. Using biosensor assays, biophysical protein characterization methods, microscale thermophoresis, swarming motility assays, growth assays, as well as molecular docking, we show that aspartame, sucralose, and saccharin have significant inhibitory actions on the Gram-negative bacteria N-acyl homoserine lactone-based (AHL) communication system. Our studies indicate that these three artificial sweeteners are not bactericidal. Protein-ligand docking and interaction profiling, using LasR as a representative participating receptor for AHL, suggest that the artificial sweeteners bind to the ligand-binding pocket of the protein, possibly interfering with the proper housing of the native ligand and thus impeding protein folding. Our findings suggest that these artificial sweeteners may affect the balance of the gut microbial community via QS-inhibition. We, therefore, infer an effect of these artificial sweeteners on numerous molecular events that are at the core of intestinal microbial function, and by extension on the host metabolism.
48
Quispe-Quispe, Edwin, Anthony A. Moreira-Morrillo, and Felipe Rafael Garcés Fiallos. "A review about biocontrollers of Phytophthora capsici and its impact on Capsicum plants: A perspective from outside to inside the plant." Scientia Agropecuaria 13, no. 3 (September 21, 2022): 275–89. http://dx.doi.org/10.17268/sci.agropecu.2022.025.
Full textAbstract:
Phytophthora capsici is an oomycete that causes various symptoms, such as root, neck, stem, fruit rot, and leaf blight, in different plant species, including the genus Capsicum. One of the tools to counteract this biotic problem, which may be more profitable and respectful to the environment in the long term, is using biocontrollers such as Bacillus, Pseudomonas, Streptomyces (bacteria), and Trichoderma (fungus). It seems that each of these microorganisms has different mechanisms that allow them to inhibit and reduce the growth of P. capsici, negatively affecting the development of sporangia, germination and motility of zoospores, and expansion of germ tube. Although this direct biocontrol action on the phytopathogen correlates with the reduction of symptoms in Capsicum plants or other plant species, this would also involve the activation of defense responses in plants against P. capsici induced by microorganisms. The activity of several enzymes related to the isoflavonoid pathways and reactive oxygen species, as well as the expression of different genes that encode proteins related to pathogenesis and other proteins that can activate the jasmonic acid, salicylic acid, or ethylene signaling pathways. Despite the few existing works related to the biochemical and molecular interaction of Capsicum–P. capsici–biocontroller, in this review, we outlined and elucidated the possible effects and metabolic pathways related to this tripartite pathosystem.
49
Kováč, Ján, Nishonoy Khasanova, Tomáš Slanina, Peter Massányi, and Eva Tvrdá. "The Effect of Penicillin on the Vitality of Bull Spermatozoa." Archives of Ecotoxicology 2, no. 3 (September 30, 2020): 30–34. http://dx.doi.org/10.36547/ae.2020.2.3.30-34.
Full textAbstract:
Antibiotic supplementation into semen extenders is an important way to control several microorganisms that can affect semen quality by their presence. The objective of the present work is to estimate the effect of two different concentrations (300 µg/mL and 600 µg/mL) of penicillin on the selected quality parameters of spermatozoa collected from bulls (motility, mitochondrial activity, acrosome integrity and membrane integrity) after 0, 2 and 24 h of in vitro culture. Sperm motion was examined using HTM IVOS computer-aided sperm analysis (CASA), cell viability was assessed with the metabolic activity (MTT) assay. The acrosomal integrity was evaluated following the fast green – rose bengal staining protocol and the eosin – nigrosin staining method was used to assess the functional integrity of the sperm membrane. Our results indicate that penicillin at lower amount significantly (p>0.05) decreased the sperm motility, mitochondrial activity and membrane integrity after 24 h of in vitro culture. Supplementation of higher doses of this substance led to a significant decrease of the sperm motion during 0, 2 (p>0.05) as well as after 24 h (p>0.01), of the viability after 2 h (p>0.05) and 24 h (p>0.01), of the acrosomal integrity after 24 h (p>0.05) and of the membrane integrity at 24 h (p>0.001) too. We can consider, that the effect of penicillin addition to bovine spermatozoa during in vitro incubation is time and dose dependent.
50
Barry, Michael T., Roberto Rusconi, Jeffrey S. Guasto, and Roman Stocker. "Shear-induced orientational dynamics and spatial heterogeneity in suspensions of motile phytoplankton." Journal of The Royal Society Interface 12, no. 112 (November 2015): 20150791. http://dx.doi.org/10.1098/rsif.2015.0791.
Full textAbstract:
Fluid flow, ubiquitous in natural and man-made environments, has the potential to profoundly impact the transport of microorganisms, including phytoplankton in aquatic habitats and bioreactors. Yet, the effect of ambient flow on the swimming behaviour of phytoplankton has remained poorly understood, largely owing to the difficulty of observing cell–flow interactions at the microscale. Here, we present microfluidic experiments where we tracked individual cells for four species of motile phytoplankton exposed to a spatially non-uniform fluid shear rate, characteristic of many flows in natural and artificial environments. We observed that medium-to-high mean shear rates (1–25 s −1 ) produce heterogeneous cell concentrations in the form of regions of accumulation and regions of depletion. The location of these regions relative to the flow depends on the cells' propulsion mechanism, body shape and flagellar arrangement, as captured by an effective aspect ratio. Species having a large effective aspect ratio accumulated in the high-shear regions, owing to shear-induced alignment of the swimming orientation with the fluid streamlines. Species having an effective aspect ratio close to unity exhibited little preferential accumulation at low-to-moderate flow rates, but strongly accumulated in the low-shear regions under high flow conditions, potentially owing to an active, behavioural response of cells to shear. These observations demonstrate that ambient fluid flow can strongly affect the motility and spatial distribution of phytoplankton and highlight the rich dynamics emerging from the interaction between motility, morphology and flow.