scholarly journals Effect of Bacteriophages and Gentamycine on Morphology and Vesicle Formation of Bacteria Yersinia pestis EV

2019 ◽  
pp. 50-54 ◽  
Author(s):  
L. G. Dudina ◽  
M. A. Malkova ◽  
A. V. Chernyad’ev ◽  
S. G. Litvinets ◽  
A. A. Byvalov
Keyword(s):  
Yersinia Pestis ◽  
Vaccine Strain ◽  
Stress Factors ◽  
Growth Media ◽  
Vesicle Formation ◽  
Microbial Culture ◽  
Bacterial Cells ◽  
Cultivation Conditions ◽  
Functional Changes ◽  
Transmission Electron

Objective was to assess the effect of specific bacteriophages and gentamycine on the morphological-functional properties of bacteria in the vaccine strain Yersinia pestis EV.Materials and methods. The vaccine strain Y. pestis EV, Pokrovskaya bacteriophage and the pseudotuberculous diagnostic bacteriophage were used for the study. The microbial culture was grown on solid and in liquid growth media at 27 °C for 20–24 h. The co-incubation of bacteria and bacteriophage or gentamycine was carried out at 27 °C for 20 minutes or at 37 °C for 2 hours, respectively. Culture preparations were examined by transmission electron microscopy.Results and discussion. The influence of cultivation conditions and various stress factors on the vesicle production by the vaccine strain Y. pestis EV cells was evaluated. The nature and intensity of morphological-functional changes in Y. pestis EV cells in response to the effect of bacteriophages (plague Pokrovskaya and pseudotuberculous bacteriophages) or an antibiotic (gentamycine) were determined. It was established that co-incubation of Y. pestis EV with Pokrovskaya bacteriophage or gentamycine for 20 min leads to the increase in the production of extracellular vesicles and is accompanied by the development of degenerative changes in bacterial cells. 

scholarly journals CdSe QD Biosynthesis in Yeast Using Tryptone-Enriched Media and Their Conjugation with a Peptide Hecate for Bacterial Detection and Killing

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1463 ◽  
Author(s):  
Vishma Pratap Sur ◽  
Marketa Kominkova ◽  
Zaneta Buchtova ◽  
Kristyna Dolezelikova ◽  
Ondrej Zitka ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Synthesis Process ◽  
Synthesis Methods ◽  
Bacterial Cells ◽  
Cdse Qds ◽  
Yeast Saccharomyces Cerevisiae ◽  
Shape Distribution ◽  
Transmission Electron ◽  
A Cell ◽  
Physical And Chemical

The physical and chemical synthesis methods of quantum dots (QDs) are generally unfavorable for biological applications. To overcome this limitation, the development of a novel “green” route to produce highly-fluorescent CdSe QDs constitutes a promising substitute approach. In the present work, CdSe QDs were biosynthesized in yeast Saccharomyces cerevisiae using a novel method, where we showed for the first time that the concentration of tryptone highly affects the synthesis process. The optimum concentration of tryptone was found to be 25 g/L for the highest yield. Different methods were used to optimize the QD extraction from yeast, and the best method was found to be by denaturation at 80 °C along with an ultrasound needle. Multiple physical characterizations including transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and spectrophotometry confirmed the optical features size and shape distribution of the QDs. We showed that the novel conjugate of the CdSe QDs and a cell-penetrating peptide (hecate) can detect bacterial cells very efficiently under a fluorescent microscope. The conjugate also showed strong antibacterial activity against vancomycin-resistant Staphylococcus aureus (VRSA), methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli, which may help us to cope with the problem of rising antibiotic resistance.

scholarly journals Zinc Oxide and Silver Nanoparticle Effects on Intestinal Bacteria

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2489
Author(s):  
Ami Yoo ◽  
Mengshi Lin ◽  
Azlin Mustapha
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Morphological Changes ◽  
Intestinal Bacteria ◽  
Bacterial Cells ◽  
Ag Nps ◽  
Zno Nps ◽  
Bifidobacterium Animalis ◽  
Transmission Electron

The application of nanoparticles (NPs) for food safety is increasingly being explored. Zinc oxide (ZnO) and silver (Ag) NPs are inorganic chemicals with antimicrobial and bioactive characteristics and have been widely used in the food industry. However, not much is known about the behavior of these NPs upon ingestion and whether they inhibit natural gut microflora. The objective of this study was to investigate the effects of ZnO and Ag NPs on the intestinal bacteria, namely Escherichia coli, Lactobacillus acidophilus, and Bifidobacterium animalis. Cells were inoculated into tryptic soy broth or Lactobacilli MRS broth containing 1% of NP-free solution, 0, 12, 16, 20 mM of ZnO NPs or 0, 1.8, 2.7, 4.6 mM Ag NPs, and incubated at 37 °C for 24 h. The presence and characterization of the NPs on bacterial cells were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Membrane leakage and cell viability were assessed using a UV-visible spectrophotometer and confocal electron microscope, respectively. Numbers of treated cells were within 1 log CFU/mL less than those of the controls for up to 12 h of incubation. Cellular morphological changes were observed, but many cells remained in normal shapes. Only a small amount of internal cellular contents was leaked due to the NP treatments, and more live than dead cells were observed after exposure to the NPs. Based on these results, we conclude that ZnO and Ag NPs have mild inhibitory effects on intestinal bacteria.

scholarly journals Microbial Photoinactivation by Visible Light Results in Limited Loss of Membrane Integrity

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 341
Author(s):  
Katharina Hoenes ◽  
Richard Bauer ◽  
Barbara Spellerberg ◽  
Martin Hessling
Keyword(s):  
Visible Light ◽  
Pseudomonas Fluorescens ◽  
Bacterial Cell ◽  
Bacterial Species ◽  
Membrane Integrity ◽  
Cell Lysis ◽  
Microbial Inactivation ◽  
Bacterial Cells ◽  
Resistance Development ◽  
Transmission Electron

Interest in visible light irradiation as a microbial inactivation method has widely increased due to multiple possible applications. Resistance development is considered unlikely, because of the multi-target mechanism, based on the induction of reactive oxygen species by wavelength specific photosensitizers. However, the affected targets are still not completely identified. We investigated membrane integrity with the fluorescence staining kit LIVE/DEAD® BacLight™ on a Gram positive and a Gram negative bacterial species, irradiating Staphylococcus carnosus and Pseudomonas fluorescens with 405 nm and 450 nm. To exclude the generation of viable but nonculturable (VBNC) bacterial cells, we applied an ATP test, measuring the loss of vitality. Pronounced uptake of propidium iodide was only observed in Pseudomonas fluorescens at 405 nm. Transmission electron micrographs revealed no obvious differences between irradiated samples and controls, especially no indication of an increased bacterial cell lysis could be observed. Based on our results and previous literature, we suggest that visible light photoinactivation does not lead to rapid bacterial cell lysis or disruption. However, functional loss of membrane integrity due to depolarization or inactivation of membrane proteins may occur. Decomposition of the bacterial envelope following cell death might be responsible for observations of intracellular component leakage.

scholarly journals Adhesive properties of an outer structure of Clostridium perfringens type A isolated from piglets with with catarrhal enteritis

1999 ◽  
Vol 30 (3) ◽  
pp. 242-248 ◽  
Author(s):  
Elizabeth Pelosi Teixeira ◽  
Marlene Braide Serafim ◽  
Maria Alice Cruz Höfling ◽  
Aureo T. Yamada ◽  
Antonio Fernando Pestana de Castro
Keyword(s):  
Clostridium Perfringens ◽  
Type A ◽  
Negative Control ◽  
Bacterial Cells ◽  
Intestinal Epithelial ◽  
Adhesive Properties ◽  
Ileal Loop ◽  
Fibrillar Material ◽  
Gram Staining ◽  
Transmission Electron

One strain (S32) of Clostridium perfringens type A was isolated from a case of catarrhal enteritis of piglets. This strain was able to adhere to HeLa cells showing an adherence index (AI) of 25.15 ± 1.26 (mean ± 1 standard error of the mean). Treatment of the bacterial cells with trypsin (0.25mg/ml) decreased in 70%-80% the AI and metaperiodate (10mg/ml) abolished completely the adherence, suggesting that the structure responsible for this phenomenon was probably a glycoprotein. Heating of bacterial suspensions (100ºC/5 min) before carrying out the adhesion test decreased the AI rendering it equal to the negative controls. Rabbit homologous S32 antiserum inhibited the adherence up to dilutions of 1: 640, at least. The piglet ileal loop assay, carried out with strains S32 and Jab-1 (negative control) demonstrated that the strain S32 was able to adhere to the intestinal epithelial cells when examined after Gram staining. Transmission electron microcopy (TEM) demonstrated that S32 strain displayed a loose fibrillar material not seen with Jab-1. Stabilization of the bacterial cells with homologous antiserum of strain S32, followed by staining with rhuteniun red, revealed loose long fibrillar material on the outer surface of the cells, that sometimes could be seen spreading out from the cells and linking bacterial cells. The question whether this structure might be an adhesin for this strain of Cl. perfringes type A, perhaps playing a role in the pathogenesis of the catarrhal enteritis of piglets, is dependent on further studies.

Controlled lysis of bacterial cells utilizing mutants with defective synthesis of D-alanine

1988 ◽  
Vol 34 (3) ◽  
pp. 256-261 ◽  
Author(s):  
Michael P. Heaton ◽  
Robert B. Johnston ◽  
Thomas L. Thompson
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Walls ◽  
Alanine Racemase ◽  
Growth Media ◽  
Bacterial Cells ◽  
Cell Wall Formation ◽  
Fermentation Processes ◽  
Intracellular Enzymes ◽  
Dense Cell

An alanine racemase (EC 5.1.1.1) mutant (Dal−) of Bacillus subtilis required small amounts of D-alanine to synthesize an osmotically stable cell wall in certain growth media. Investigation of the conditions which caused lysis in hypotonic media revealed that in addition to complex media, such as nutrient broth and acid-hydrolyzed casein, glycine inhibited stable cell wall formation. D-Alanine prevented the glycine inhibition. Up to 99% lysis occurred in both dilute and dense cell suspensions (optical densities up to 110) within 2.5 h after adding 1% glycine to late log phase cultures. Intracellular enzymes recovered from the lysate were as active as those from lysozyme-disrupted cells. No amino acid tested other than glycine induced lysis. Dal− mutants can be used for controlled lysis of bacterial cells to facilitate the isolation of normal intracellular constituents and bioengineered products from fermentation processes. Cell walls of most bacteria contain D-alanine; thus, this strategy should be applicable to a wide variety of microorganisms.

scholarly journals Chromate Reduction in Serratia marcescens Isolated from Tannery Effluent and Potential Application for Bioremediation of Chromate Pollution

2002 ◽  
Vol 2 ◽  
pp. 972-977 ◽  
Author(s):  
M.A. Mondaca ◽  
V. Campos ◽  
R. Moraga ◽  
C.A. Zaror
Keyword(s):  
Natural Waters ◽  
Waste Treatment ◽  
Environmental Concern ◽  
Electron Microscopic Examination ◽  
Tannery Effluent ◽  
Chromate Reduction ◽  
Bacterial Cells ◽  
Electron Microscopic ◽  
Treatment Processes ◽  
Transmission Electron

Pollution of aquatic systems by heavy metals has resulted in increasing environmental concern because they cannot be biodegraded. One metal that gives reason for concern due to its toxicity is chromium. Cr(VI) and Cr(III) are the principal forms of chromium found in natural waters. A chromate-resistant strain of the bacterium S. marcescens was isolated from tannery effluent. The strain was able to reduce Cr(VI) to Cr(III), and about 80% of chromate was removed from the medium. The reduction seems to occur on the cell surface. Transmission electron microscopic examination of cells revealed that particles were deposited on the outside of bacterial cells. A stable biofilm was formed in less than 10 h, reaching around 1010cfu attached per milligram of activated carbon. These findings demonstrate that immobilizedS. marcescensmight be used in industrial waste treatment processes.

scholarly journals Novel 5′-Norcarbocyclic Pyrimidine Derivatives as Antibacterial Agents

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3069 ◽  
Author(s):  
Anastasia Khandazhinskaya ◽  
Liudmila Alexandrova ◽  
Elena Matyugina ◽  
Pavel Solyev ◽  
Olga Efremenkova ◽  
...  
Keyword(s):  
Mycobacterium Smegmatis ◽  
Multiple Drug Resistance ◽  
Laboratory Strain ◽  
Clinical Strain ◽  
Multiple Drug ◽  
Bacterial Cells ◽  
Transmission Electron ◽  
Virulent Strains ◽  
Derivatives Of ◽  
Strain H37rv

A series of novel 5′-norcarbocyclic derivatives of 5-alkoxymethyl or 5-alkyltriazolyl-methyl uracil were synthesized and the activity of the compounds evaluated against both Gram-positive and Gram-negative bacteria. The growth of Mycobacterium smegmatis was completely inhibited by the most active compounds at a MIC99 of 67 μg/mL (mc2155) and a MIC99 of 6.7–67 μg/mL (VKPM Ac 1339). Several compounds also showed the ability to inhibit the growth of attenuated strains of Mycobacterium tuberculosis ATCC 25177 (MIC99 28–61 μg/mL) and Mycobacterium bovis ATCC 35737 (MIC99 50–60 μg/mL), as well as two virulent strains of M. tuberculosis; a laboratory strain H37Rv (MIC99 20–50 μg/mL) and a clinical strain with multiple drug resistance MS-115 (MIC99 20–50 μg/mL). Transmission electron microscopy (TEM) evaluation of M. tuberculosis H37Rv bacterial cells treated with one of the compounds demonstrated destruction of the bacterial cell wall, suggesting that the mechanism of action for these compounds may be related to their interactions with bacteria cell walls.

Reduction of selenate and selenite to elemental selenium by Wolinella succinogenes

1992 ◽  
Vol 38 (12) ◽  
pp. 1328-1333 ◽  
Author(s):  
Francisco A. Tomei ◽  
Larry L. Barton ◽  
Cheryl L. Lemanski ◽  
Thomas G. Zocco
Keyword(s):  
Stationary Growth Phase ◽  
Elemental Selenium ◽  
Bacterial Cells ◽  
Wolinella Succinogenes ◽  
Stationary Growth ◽  
X Ray ◽  
Dense Granules ◽  
Transmission Electron ◽  
Final Electron ◽  
Final Electron Acceptor

Cultures of Wolinella succinogenes were adapted to grow in the presence of 1 mM [Formula: see text] or 10 mM [Formula: see text]. Both selenium salts were reduced to red, amorphous, elemental selenium but only after the culture reached the stationary growth phase. Bacterial cells taken from a culture actively reducing selenium were examined by transmission electron microscopy and were found to have large, electron-dense granules in the cytoplasm. These granules were verified by energy-dispersive X-ray spectroscopy to consist of selenium. Wolinella succinogenes was unable to grow with [Formula: see text] or [Formula: see text] as the final electron acceptor. Key words: Wolinella, selenium, cytology, selenate.

Influence of Carvacrol and 1,8-Cineole on Cell Viability, Membrane Integrity, and Morphology of Aeromonas hydrophila Cultivated in a Vegetable-Based Broth

2015 ◽  
Vol 78 (2) ◽  
pp. 424-429 ◽  
Author(s):  
JOSSANA PEREIRA de SOUSA ◽  
KATARYNE ÁRABE RIMÁ de OLIVEIRA ◽  
REGINA CELIA BRESSAN QUEIROZ de FIGUEIREDO ◽  
EVANDRO LEITE de SOUZA
Keyword(s):  
Cell Viability ◽  
Membrane Permeability ◽  
Aeromonas Hydrophila ◽  
Membrane Integrity ◽  
Cell Membrane Permeability ◽  
Confocal Laser ◽  
Wall Structure ◽  
Bacterial Cells ◽  
Transmission Electron ◽  
Cytoplasmic Content

This study investigated the effects of carvacrol (CAR) and 1,8-cineole (CIN) alone (at the MIC) or in combination at subinhibitory amounts (both at 1/8 MIC) on the cell viability, membrane permeability, and morphology of Aeromonas hydrophila INCQS 7966 (A. hydrophila) cultivated in a vegetable-based broth. CAR and CIN alone or in combination severely affected the viability of the bacteria and caused dramatic changes in the cell membrane permeability, leading to cell death, as observed by confocal laser microscopy. Scanning and transmission electron microscopy images of bacterial cells exposed to CAR or CIN or the mixture of both compounds revealed severe changes in cell wall structure, rupture of the plasma membrane, shrinking of cells, condensation of cytoplasmic content, leakage of intracellular material, and cell collapse. These findings suggest that CAR and CIN alone or in combination at subinhibitory amounts could be applied to inhibit the growth of A. hydrophila in foods, particularly as sanitizing agents in vegetables.

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