scholarly journals Patterns of bacterial motility in microfluidics-confining environments

2021 ◽  
Vol 118 (17) ◽  
pp. e2013925118
Author(s):  
Viola Tokárová ◽  
Ayyappasamy Sudalaiyadum Perumal ◽  
Monalisha Nayak ◽  
Henry Shum ◽  
Ondřej Kašpar ◽  
...  
Keyword(s):  
Vibrio Fischeri ◽  
Bacterial Species ◽  
Physical Space ◽  
Concentration Gradients ◽  
Open Spaces ◽  
Steric Interactions ◽  
E Coli ◽  
Geometrical Complexity ◽  
Genomic Screening ◽  
Motility Behavior

Understanding the motility behavior of bacteria in confining microenvironments, in which they search for available physical space and move in response to stimuli, is important for environmental, food industry, and biomedical applications. We studied the motility of five bacterial species with various sizes and flagellar architectures (Vibrio natriegens, Magnetococcus marinus, Pseudomonas putida, Vibrio fischeri, and Escherichia coli) in microfluidic environments presenting various levels of confinement and geometrical complexity, in the absence of external flow and concentration gradients. When the confinement is moderate, such as in quasi-open spaces with only one limiting wall, and in wide channels, the motility behavior of bacteria with complex flagellar architectures approximately follows the hydrodynamics-based predictions developed for simple monotrichous bacteria. Specifically, V. natriegens and V. fischeri moved parallel to the wall and P. putida and E. coli presented a stable movement parallel to the wall but with incidental wall escape events, while M. marinus exhibited frequent flipping between wall accumulator and wall escaper regimes. Conversely, in tighter confining environments, the motility is governed by the steric interactions between bacteria and the surrounding walls. In mesoscale regions, where the impacts of hydrodynamics and steric interactions overlap, these mechanisms can either push bacteria in the same directions in linear channels, leading to smooth bacterial movement, or they could be oppositional (e.g., in mesoscale-sized meandered channels), leading to chaotic movement and subsequent bacterial trapping. The study provides a methodological template for the design of microfluidic devices for single-cell genomic screening, bacterial entrapment for diagnostics, or biocomputation.

Efficacy of Silver Nanoparticles Synthesized from Hymenocallis species (Spider Lilly) Leaf Extract as Antimicrobial Agents

2019 ◽  
Vol 12 (5) ◽  
pp. 4644-4647
Author(s):  
K.K. Gupta ◽  
Neha Kumari ◽  
Neha Sinha ◽  
Akruti Gupta
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Antimicrobial Agents ◽  
Color Change ◽  
Bacterial Species ◽  
Antimicrobial Property ◽  
Biogenic Synthesis ◽  
E Coli ◽  
Light Yellow ◽  
Antibiotic Property

Biogenic synthesis of silver nanoparticles synthesized from Hymenocallis species (Spider Lilly) leaf extract was subjected for investigation of its antimicrobial property against four bacterial species (E. coli, Salmonella sp., Streptococcus sp. & Staphylococcus sp.). The results revealed that synthesized nanoparticles solution very much justify the color change property from initial light yellow to final reddish brown during the synthesis producing a characteristics absorption peak in the range of 434-466 nm. As antimicrobial agents, their efficacy was evaluated by analysis of variance in between the species and among the different concentration of AgNPs solution, which clearly showed that there was significant variation in the antibiotic property between the four different concentrations of AgNPs solution and also among four different species of bacteria taken under studies. However, silver nanoparticles solution of 1: 9 and 1:4 were proved comparatively more efficient as antimicrobial agents against four species of bacteria.

Substituted 6,7-dimethoxy-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole- 3-1,1-dioxide Derivatives with Antimicrobial Activity and Docking Assisted Prediction of the Mechanism of their Antibacterial and Antifungal Properties

2020 ◽  
Vol 20 (29) ◽  
pp. 2681-2691
Author(s):  
Athina Geronikaki ◽  
Victor Kartsev ◽  
Phaedra Eleftheriou ◽  
Anthi Petrou ◽  
Jasmina Glamočlija ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antifungal Activity ◽  
Drug Targets ◽  
Bacterial Species ◽  
Pharmaceutical Research ◽  
Docking Studies ◽  
Fungal Species ◽  
Docking Analysis ◽  
E Coli ◽  
Antibacterial And Antifungal

Background: Although a great number of the targets of antimicrobial therapy have been achieved, it remains among the first fields of pharmaceutical research, mainly because of the development of resistant strains. Docking analysis may be an important tool in the research for the development of more effective agents against specific drug targets or multi-target agents 1-3. Methods: In the present study, based on docking analysis, ten tetrahydrothiazolo[2,3-a]isoindole derivatives were chosen for the evaluation of the antimicrobial activity. Results: All compounds showed antibacterial activity against eight Gram-positive and Gram-negative bacterial species being, in some cases, more potent than ampicillin and streptomycin against all species. The most sensitive bacteria appeared to be S. aureus and En. Cloacae, while M. flavus, E. coli and P. aeruginosa were the most resistant ones. The compounds were also tested for their antifungal activity against eight fungal species. All compounds exhibited good antifungal activity better than reference drugs bifonazole (1.4 – 41 folds) and ketoconazole (1.1 – 406 folds) against all fungal species. In order to elucidate the mechanism of action, docking studies on different antimicrobial targets were performed. Conclusion: According to docking analysis, the antifungal activity can be explained by the inhibition of the CYP51 enzyme for most compounds with a better correlation of the results obtained for the P.v.c. strain (linear regression between estimated binding Energy and log(1/MIC) with R 2 =0.867 and p=0.000091 or R 2 = 0.924, p= 0.000036, when compound 3 is excluded.

scholarly journals Evolution of Chi motifs in Proteobacteria

2021 ◽  
Author(s):  
Angélique Buton ◽  
Louis-Marie Bobay
Keyword(s):  
Sequence Similarity ◽  
Bacterial Species ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Large Dataset ◽  
High Sequence Similarity ◽  
Strand Breaks ◽  
E Coli ◽  
Dna Motif ◽  
And Staphylococcus Aureus

Abstract Homologous recombination is a key pathway found in nearly all bacterial taxa. The recombination complex allows bacteria to repair DNA double strand breaks but also promotes adaption through the exchange of DNA between cells. In Proteobacteria, this process is mediated by the RecBCD complex, which relies on the recognition of a DNA motif named Chi to initiate recombination. The Chi motif has been characterized in Escherichia coli and analogous sequences have been found in several other species from diverse families, suggesting that this mode of action is widespread across bacteria. However, the sequences of Chi-like motifs are known for only five bacterial species: E. coli, Haemophilus influenzae, Bacillus subtilis, Lactococcus lactis and Staphylococcus aureus. In this study we detected putative Chi motifs in a large dataset of Proteobacteria and we identified four additional motifs sharing high sequence similarity and similar properties to the Chi motif of E. coli in 85 species of Proteobacteria. Most Chi motifs were detected in Enterobacteriaceae and this motif appears well conserved in this family. However, we did not detect Chi motifs for the majority of Proteobacteria, suggesting that different motifs are used in these species. Altogether these results substantially expand our knowledge on the evolution of Chi motifs and on the recombination process in bacteria.

scholarly journals Characterization of Escherichia coli Strains Derived from Cow Milk of Subclinical and Clinical Cases of Mastitis

2021 ◽  
Vol 11 (2) ◽  
pp. 541
Author(s):  
Katarzyna Grudlewska-Buda ◽  
Krzysztof Skowron ◽  
Ewa Wałecka-Zacharska ◽  
Natalia Wiktorczyk-Kapischke ◽  
Jarosław Bystroń ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Species ◽  
Subclinical Mastitis ◽  
Clinical Mastitis ◽  
Economic Problem ◽  
Cow Milk ◽  
P Value ◽  
Dairy Herds ◽  
E Coli ◽  
Bonferroni Test

Mastitis is a major economic problem in dairy herds, as it might decrease fertility, and negatively affect milk quality and milk yield. Out of over 150 bacterial species responsible for the udder inflammation, Escherichia coli is one of the most notable. This study aimed to assess antimicrobial susceptibility, resistance to dipping agents and biofilm formation of 150 E. coli strains isolated from milk of cows with subclinical and clinical mastitis. The strains came from three dairy herds located in Northern and Central Poland. The statistical analyses were performed with post-hoc Bonferroni test and chi-square test (including Yates correction). The data with a p value of <0.05 were considered significant. We found that the tested strains were mostly sensitive to antimicrobials and dipping agents. It was shown that 37.33% and 4.67% of strains were resistant and moderately resistant to at least one antimicrobial agent, respectively. No extended-spectrum beta-lactamases (ESBL)-producing E. coli were detected. The majority of strains did not possess the ability to form biofilm or formed a weak biofilm. The strong biofilm formers were found only among strains derived from cows with subclinical mastitis. The lowest bacteria number was noted for subclinical mastitis cows’ strains, after stabilization with iodine (3.77 log CFU × cm−2) and chlorhexidine (3.96 log CFU × cm−2) treatment. In the present study, no statistically significant differences in susceptibility to antibiotics and the ability to form biofilm were found among the strains isolated from cows with subclinical and clinical mastitis. Despite this, infections in dairy herds should be monitored. Limiting the spread of bacteria and characterizing the most common etiological factors would allow proper treatment.

scholarly journals Enhancing Terpene Yield from Sugars via Novel Routes to 1-Deoxy-d-Xylulose 5-Phosphate

2014 ◽  
Vol 81 (1) ◽  
pp. 130-138 ◽  
Author(s):  
James Kirby ◽  
Minobu Nishimoto ◽  
Ruthie W. N. Chow ◽  
Edward E. K. Baidoo ◽  
George Wang ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Xylose Reductase ◽  
Pentose Phosphate ◽  
Terpene Biosynthesis ◽  
Content Type ◽  
E Coli ◽  
Pathway Expression ◽  
Terpene Synthesis ◽  
Selection For

ABSTRACTTerpene synthesis in the majority of bacterial species, together with plant plastids, takes place via the 1-deoxy-d-xylulose 5-phosphate (DXP) pathway. The first step of this pathway involves the condensation of pyruvate and glyceraldehyde 3-phosphate by DXP synthase (Dxs), with one-sixth of the carbon lost as CO2. A hypothetical novel route from a pentose phosphate to DXP (nDXP) could enable a more direct pathway from C5sugars to terpenes and also circumvent regulatory mechanisms that control Dxs, but there is no enzyme known that can convert a sugar into its 1-deoxy equivalent. Employing a selection for complementation of adxsdeletion inEscherichia coligrown on xylose as the sole carbon source, we uncovered two candidate nDXP genes. Complementation was achieved either via overexpression of the wild-typeE. coliyajOgene, annotated as a putative xylose reductase, or via various mutations in the nativeribBgene.In vitroanalysis performed with purified YajO and mutant RibB proteins revealed that DXP was synthesized in both cases from ribulose 5-phosphate (Ru5P). We demonstrate the utility of these genes for microbial terpene biosynthesis by engineering the DXP pathway inE. colifor production of the sesquiterpene bisabolene, a candidate biodiesel. To further improve flux into the pathway from Ru5P, nDXP enzymes were expressed as fusions to DXP reductase (Dxr), the second enzyme in the DXP pathway. Expression of a Dxr-RibB(G108S) fusion improved bisabolene titers more than 4-fold and alleviated accumulation of intracellular DXP.

scholarly journals Construction and Characterization of a proU-gfp Transcriptional Fusion That Measures Water Availability in a Microbial Habitat

2002 ◽  
Vol 68 (9) ◽  
pp. 4604-4612 ◽  
Author(s):  
Catherine A. Axtell ◽  
Gwyn A. Beattie
Keyword(s):  
Pseudomonas Syringae ◽  
Water Availability ◽  
Water Deprivation ◽  
Bacterial Species ◽  
Transcriptional Fusion ◽  
Bacterial Biosensor ◽  
E Coli ◽  
Quantitative Manner ◽  
Microbial Habitat

ABSTRACT We constructed and characterized a transcriptional fusion that measures the availability of water to a bacterial cell. This fusion between the proU promoter from Escherichia coli and the reporter gene gfp was introduced into strains of E. coli, Pantoea agglomerans, and Pseudomonas syringae. The proU-gfp fusion in these bacterial biosensor strains responded in a quantitative manner to water deprivation caused by the presence of NaCl, Na2SO4, KCl, or polyethylene glycol (molecular weight, 8000). The fusion was induced to a detectable level by NaCl concentrations of as low as 10 mM in all three bacterial species. Water deprivation induced proU-gfp expression in both planktonic and surface-associated cells; however, it induced a higher level of expression in the surface-associated cells. Following the introduction of P. agglomerans biosensor cells onto bean leaves, the cells detected a significant decrease in water availability within only 5 min. After 30 min, the populations were exposed, on average, to a water potential equivalent to that imposed by approximately 55 mM NaCl. These results demonstrate the effectiveness of a proU-gfp-based biosensor for evaluating water availability on leaves. Furthermore, the inducibility of proU-gfp in multiple bacterial species illustrates the potential for tailoring proU-gfp-based biosensors to specific habitats.

scholarly journals Foreshore Sand as a Source of Escherichia coli in Nearshore Water of a Lake Michigan Beach

2003 ◽  
Vol 69 (9) ◽  
pp. 5555-5562 ◽  
Author(s):  
Richard L. Whitman ◽  
Meredith B. Nevers
Keyword(s):  
Escherichia Coli ◽  
Lake Water ◽  
Lake Michigan ◽  
Beach Sand ◽  
Intensive Study ◽  
Concentration Gradients ◽  
Lake Water Quality ◽  
E Coli ◽  
Demographic Patterns ◽  
Hydrometeorological Conditions

ABSTRACT Swimming advisories due to excessive Escherichia coli concentrations are common at 63rd Street Beach, Chicago, Ill. An intensive study was undertaken to characterize the source and fate of E. coli in beach water and sand at the beach. From April through September 2000, water and sand samples were collected daily or twice daily at two depths on three consecutive days per week (water samples, n = 1,747; sand samples, n = 858); hydrometeorological conditions and bird and bather distributions were also recorded. E. coli concentrations in sand and water were significantly correlated, with the highest concentration being found in foreshore sand, followed by those in submerged sediment and water of increasing depth. Gull contributions to E. coli densities in sand and water were most apparent on the day following gull activity in a given area. E. coli recolonized newly placed foreshore sand within 2 weeks. Analysis of variance, correlation, cluster analyses, concentration gradients, temporal-spatial distribution, demographic patterns, and DNA fingerprinting suggest that E. coli may be able to sustain population density in temperate beach sand during summer months without external inputs. This research presents evidence that foreshore beach sand (i) plays a major role in bacterial lake water quality, (ii) is an important non-point source of E. coli to lake water rather than a net sink, (iii) may be environmentally, and perhaps hygienically, problematic, and (iv) is possibly capable of supporting an autochthonous, high density of indicator bacteria for sustained periods, independent of lake, human, or animal input.

scholarly journals Rapid Detection, Identification, and Enumeration ofEscherichia coli Cells in Municipal Water by Chemiluminescent In Situ Hybridization

2001 ◽  
Vol 67 (1) ◽  
pp. 142-147 ◽  
Author(s):  
Henrik Stender ◽  
Adam J. Broomer ◽  
Kenneth Oliveira ◽  
Heather Perry-O'Keefe ◽  
Jens J. Hyldig-Nielsen ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
16S Rrna ◽  
Sensitivity And Specificity ◽  
Bacterial Species ◽  
Rdna Sequence ◽  
Sequence Information ◽  
Sequence Alignments ◽  
E Coli ◽  
Municipal Water

ABSTRACT A new chemiluminescent in situ hybridization (CISH) method provides simultaneous detection, identification, and enumeration of culturableEscherichia coli cells in 100 ml of municipal water within one working day. Following filtration and 5 h of growth on tryptic soy agar at 35°C, individual microcolonies of E. coliwere detected directly on a 47-mm-diameter membrane filter using soybean peroxidase-labeled peptide nucleic acid (PNA) probes targeting a species-specific sequence in E. coli 16S rRNA. Within each microcolony, hybridized, peroxidase-labeled PNA probe and chemiluminescent substrate generated light which was subsequently captured on film. Thus, each spot of light represented one microcolony of E. coli. Following probe selection based on 16S ribosomal DNA (rDNA) sequence alignments and sample matrix interference, the sensitivity and specificity of the probe Eco16S07C were determined by dot hybridization to RNA of eight bacterial species. Only the rRNA of E. coli and Pseudomonas aeruginosa were detected by Eco16S07C with the latter mismatch hybridization being eliminated by a PNA blocker probe targetingP. aeruginosa 16S rRNA. The sensitivity and specificity for the detection of E. coli by PNA CISH were then determined using 8 E. coli strains and 17 other bacterial species, including closely related species. No bacterial strains other thanE. coli and Shigella spp. were detected, which is in accordance with 16S rDNA sequence information. Furthermore, the enumeration of microcolonies of E. coli represented by spots of light correlated 92 to 95% with visible colonies following overnight incubation. PNA CISH employs traditional membrane filtration and culturing techniques while providing the added sensitivity and specificity of PNA probes in order to yield faster and more definitive results.

Toxicity of the First Ten MEIC Chemicals to Bacteria

1993 ◽  
Vol 21 (2) ◽  
pp. 151-155
Author(s):  
Gustaw Kerszman
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Linear Regression ◽  
Minimal Inhibitory Concentration ◽  
Blood Concentration ◽  
Inhibitory Concentration ◽  
Human Lymphocytes ◽  
Bacterial Species ◽  
E Coli ◽  
Mild Toxicity

The toxicity of the first ten MEIC chemicals to Escherichia coli and Bacillus subtilis was examined. Nine of the chemicals were toxic to the bacteria, with the minimal inhibitory concentration (MIC) ranging from 10-3 to 4.4M. The sensitivities of both organisms were similar, but the effect on E. coli was often bactericidal, while it was bacteriostatic for B. subtilis. Digoxin was not detectably toxic to either bacterial species. Amitriptyline and FeSO4 were relatively less toxic to the bacteria than to human cells. For seven chemicals, a highly significant linear regression was established between log MIC in bacteria and log of blood concentration, giving lethal and moderate/mild toxicity in humans, as well as with toxicity to human lymphocytes.

STUDIES ON INTERACTION OF BACTERIA, SERUM FACTORS AND POLYMORPHONUCLEAR LEUKOCYTES IN MOTHERS AND NEWBORNS

PEDIATRICS ◽  
1969 ◽  
Vol 44 (1) ◽  
pp. 49-57 ◽  
Author(s):  
John H. Dossett ◽  
Ralph C. Williams ◽  
Paul G. Quie
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Bacterial Species ◽  
Group B Streptococcus ◽  
Newborn Infants ◽  
Maternal Serum ◽  
Humoral Factors ◽  
Serum Factors ◽  
E Coli ◽  
Serum Fractions ◽  
Group B

The bactericidal capacity of newborn infants' whole blood for E. coli was deficient compared to the mothers, and attempts were made to identify cellular or humoral factors responsible for this deficiency. Separated polymorphonuclear leukocytes from newborn infants were found to be similar to polymorphs from mothers in capacity to engulf and kill E. coli and other bacteria so that cellular deficiency was not evident. Comparison of the serum opsonic capacity of newborn infants' and mothers' sera revealed deficient opsonic capacity for E. coli in newborn sera. The mean opsonic titer for E. coli was 46.7 in mothers and 4.3 in neonates. Serum opsonic titers for Staph. aureus and group B streptococcus were similar. The opsonic capacity for all bacterial species was decreased when the sera were heated or decomplemented with immune complexes indicating the phagocytosis amplifying role of complement. The newborn-maternal difference in opsonic capacity for E. coli was presumably a result of deficient 19S antibodies, the primary opsonic antibodies for this organism. Maternal 19S serum fractions alone, however, showed no opsonic capacity for E. coli. Addition of a complement source (newborn serum absorbed with E. coli) revealed the opsonic capacity of these 19S maternal serum fractions for E. coli. Antibodies in 19S serum fractions therefore are efficient opsonins for E. coli; however, complement is necessary to demonstrate their opsonic potential.

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