scholarly journals A CYTOCHEMICAL LOCALIZATION OF REDUCTIVE SITES IN A GRAM-NEGATIVE BACTERIUM

1964 ◽  
Vol 20 (3) ◽  
pp. 377-387 ◽  
Author(s):  
Woutera van Iterson ◽  
W. Leene
Keyword(s):  
Plasma Membrane ◽  
Electron Scattering ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Electron Microscopic ◽  
Cytochemical Localization ◽  
Gram Negative ◽  
Living State ◽  
Granular Matrix ◽  
Reducing Activity

In order to obtain information on the exact location of the respiratory enzyme chain in Gram-negative bacteria, an electron microscopic study was made of the sites of reducing activity of cells that had, in the living state, incorporated tellurite. In the test object Proteus vulgaris, the reduced tellurite was found to be deposited in bodies contiguous with the plasma membrane but different in structure from those described in the Gram-positive Bacillus subtilis (2). In fact, the bodies proved to consist of a conglomerate of elements which contained the strongly electron-scattering reduced tellurite and a delicately granular "matrix." A limiting membrane was not observed around these complexes. In serial sections details of the complexes are illustrated. Reduced tellurite was not deposited in the plasma membrane to any important degree. Since no other sites of deposition of the reduced product were revealed, it is assumed that the complexes represent the mitochondrial equivalents in the investigated organism. In addition, the bodies might function as the basal granules of the flagella.

Ultrastructural studies of Chlamydia psittaci 6BC variant strains. I. Ultrastructure of the surface layers of egg-passaged 6BC strain

1973 ◽  
Vol 19 (8) ◽  
pp. 887-894
Author(s):  
Linda Poffenroth ◽  
J. W. Costerton ◽  
Nonna Kordová ◽  
John C. Wilt
Keyword(s):  
Chick Embryo ◽  
Microscopic Examination ◽  
Electron Microscopic Examination ◽  
Chlamydia Psittaci ◽  
Gram Negative Bacteria ◽  
Surface Layers ◽  
Electron Microscopic ◽  
Gram Negative ◽  
Ultrastructural Studies ◽  
First Time

Electron microscopic examination of a semipurified Chlamydia psittaci 6BC strain attenuated in chick embryo yolk sac revealed for the first time two morphologically distinct small elementary bodies which differ both in the ultrastructure of their surface layers and in their buoyant densities in sucrose gradients. Also, the morphology of the surface layers of the larger reticulate forms in cell-free systems is described for the first time. Many points of difference between the surface envelopes and internal structure of chlamydial particles and those of Gram-negative bacteria are discussed.

scholarly journals Antimicrobial Activity of Gardenia jasminoides Callus and Crude Leaf Extracts for some Organic Solvents against some Pathogenic Bacteria and Yeasts

2014 ◽  
Vol 8 (3) ◽  
pp. 40-45
Author(s):  
Zina Hashem Shehab ◽  
Huda Suhail Abid ◽  
Sumaya Fadhil Hamad ◽  
Sara Haitham
Keyword(s):  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Pathogenic Bacteria ◽  
Saccharomyces Boulardii ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Gardenia Jasminoides

The study was conducted to evaluate the inhibitory activity of methanol extract of Gardenia jasminoides leaves compared with leaf crude extracts for some organic solvents namely Methanol, Ethanol, Petroleum ether, Asetone and Chloroform on growth of some pathogenic bacteria and yeast, which included four gram positive isolates Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes and Bacillus cereus and gram negative isolates Escherichia coli, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa and some yeasts Candida albicans and Saccharomyces boulardii, by using well diffusion method. The inhibitory activity of extracts in the tested bacterial strains and yeasts was varied according to the type of extracting solvents and are tested microorganisms. The methanol callus extract which grown on Murashige and Skoog (MS) media by using (Naphthalen acitic acid) NAA and (Benzyle adenine) BA as growth regulator highly effective as compared to the other extracts as for inhibition of three gram positive bacteria and three gram negative bacteria,which include Staphylococcus aureus and, Proteus vulgaris, followed by acetone and ethanolic extracts which include two gram positive bacteria and two gram negative bacteria. All extracts had highly effect in growth of Candida albicans while all crude extracts didn’t show any sensitivity against Saccharomyces boulardii, and when we’d done (High Performance Liquid Chromatography) HPLC test for detection of some active compound we found Quinic acid, Iridiods glycosides and Crocin which its rate in fresh callus was higher than fresh leaves.

scholarly journals A CYTOCHEMICAL LOCALIZATION OF REDUCTIVE SITES IN A GRAM-POSITIVE BACTERIUM

1964 ◽  
Vol 20 (3) ◽  
pp. 361-375 ◽  
Author(s):  
Woutera van Iterson ◽  
W. Leene
Keyword(s):  
Plasma Membrane ◽  
Cell Periphery ◽  
Gram Positive ◽  
Cytochemical Localization ◽  
Potassium Tellurite ◽  
Thin Sections ◽  
Gram Positive Bacteria ◽  
Cytoplasmic Membranes ◽  
Reducing Activity ◽  
The One

In bacteria the exact location of a respiratory enzyme system comparable to that of the mitochondria of other cells has remained uncertain. On the one hand, the existence of particulate "bacterial mitochondria" has been advocated (Mudd); on the other hand, important enzymes of the respiratory chain were recovered in the cytoplasmic membranes associated with some granular material (Weibull). In order to gain insight into this question, sites of reducing activity were localized in thin sections of bacteria using the reduction of potassium tellurite as an indicator. When this salt was added to the culture medium of Bacillus subtilis, it turned out that in this Gram-positive organism the reduced product is strictly bound at two sites, and that the plasma membrane does not materially gain in electron opacity through deposition of the reduced product. The reduction product is found on or in the membranes of particular organelles, which may possibly be regarded as the mitochondrial equivalents in Gram-positive bacteria, and which are sometimes seen connected to the plasma membrane. The second location is in thin rod-like elements at the cell periphery, possibly the sites from which the flagella emerge.

Fine structure of selected species of the genus Thiobacillus as revealed by chemical fixation and freeze-etching

1974 ◽  
Vol 20 (10) ◽  
pp. 1347-1351 ◽  
Author(s):  
Stanley C. Holt ◽  
J. M. Shively ◽  
J. W. Greenawalt
Keyword(s):  
Inclusion Bodies ◽  
Convex Surface ◽  
Cell Envelope ◽  
Electron Microscopic Examination ◽  
Gram Negative Bacteria ◽  
Chemical Fixation ◽  
Electron Microscopic ◽  
Gram Negative ◽  
Freeze Etching ◽  
Outer Plasma Membrane

An electron-microscopic examination of selected species of the genus Thiobacillus was undertaken using the techniques of chemical fixation and freeze-etching. The architecture of the cells was typical of gram-negative bacteria. The multilayered cell envelope was revealed as a complex of smooth, rough, and particle-studded membranes. The particles which covered the outer plasma membrane (convex surface) appeared to contain a differentiated region which might permit a channeling between the exterior and interior of the cell. Inclusion bodies, including paracrystalline arrays, carboxysomes, and granules were present.

scholarly journals Identification of the microflora from the oral cavity of exotic snakes kepth as pets

2020 ◽  
Vol 12 (2) ◽  
pp. 56-63
Author(s):  
Marko Naumovski ◽  
Ivamaria Jovanovska ◽  
Kakja Popovska ◽  
Vesna Velikj Stefanovska ◽  
Gordana Mirchevska
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Oral Cavity ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Gram Positive ◽  
Providencia Rettgeri ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Venomous Snakes ◽  
The Republic

In recent years, snakes have become suitable pets for people with little spare time. By buying these animals people ignore the fact that they carry many microorganisms that are pathogenic for humans. The idea of ​​this study was to identify the microorganisms from the oral cavity of exotic snakes kept as pets in the Republic of North Macedonia, which can help in the treatment of bite infections if they occur. The study comprised 30 snakes of 9 species, from 3 families of non-venomous snakes: Pythonidae, Boidae and Colubridae. Snakes are part of the 5 largest collections of exotic snakes in the Republic of North Macedonia. Only one swab from the oral cavity was taken from each snake. The brushes were cultured and microscopically analyzed at the Institute of Microbiology and Parasitology at the Faculty of Medicine in Skopje. From 59 isolated microorganisms from the oral cavity of 30 exotic snakes, 37.3% were Gram-positive bacteria, 61.01% were Gram-negative bacteria and 1.69% were fungi. Of the total number of microorganisms, Pseudomonas aeruginosa was predominant with 27.11%, Providencia rettgeri / Proteus vulgaris with 18.64% and KONS / Micrococcus luteus with 16.94%. Pseudomonas aeruginosa was present in all three snake families, with 62.5% of the snake in the fam. Pythonidae; 50% in the fam. Boidae and 50% in the fam. Colubridae. The isolate Providencia rettgeri / Proteus vulgaris was most frequently found in the fam. Colubridae with 71.43%, followed by fam. Pythonidae with 12.5%, but was not isolated in any specimen of the fam. Boidae. The microbiome of the non-venomous snakes is composed of Gram-positive bacteria in healthy snakes, but also in snakes kept in inadequate hygienic conditions. Gram-negative bacteria were predominant, of which the most significant was the presence of multiple drug resistance Pseudomonas aeruginosa. Snakes as pets require proper knowledge of terms and conditions.

LYSOZYME IN THE BACTERIOLYSIS OF GRAM-NEGATIVE BACTERIA: I. MORPHOLOGICAL CHANGES DURING USE OF NAKAMURA'S TECHNIQUE

1957 ◽  
Vol 3 (1) ◽  
pp. 13-21 ◽  
Author(s):  
E. A. Grula ◽  
S. E. Hartsell
Keyword(s):  
Electron Microscope ◽  
Cell Walls ◽  
Light Transmission ◽  
Morphological Changes ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Gram Negative ◽  
Whole Cells ◽  
Sequence Of Events ◽  
Reversible Hydration

Whole cells or the cell walls of 22 species representing 11 genera of Gram-negative bacteria were exposed to lysozyme using a modified Nakamura technique. The cell walls of all organisms contain the lysozyme substrate in differing amounts (two Brucella spp., Proteus vulgaris X-19, and Vibrio cholerae Chicago are possible exceptions) when evaluated spectrophotometrically and with the electron microscope. Using the latter technique, the sequence of events during bacteriolysis with lysozyme was observed. After exposure to lysozyme in saline, with the modified Nakamura technique and the phase microscope, cells were observed to either swell or shrink depending on the pH of the menstruum. This phenomenon apparently involves reversible hydration of cell proteins with concomitant changes in light transmission.

Electron Microscopic Observations on the Effects of Polymixin B Sulfate to Cell Walls of Chlamydia Organisms

1972 ◽  
Vol 30 ◽  
pp. 326-327
Author(s):  
Akira Matsumoto
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Present Report ◽  
Bactericidal Effect ◽  
Chlamydia Psittaci ◽  
Gram Negative Bacteria ◽  
Electron Microscopic ◽  
Cell Content ◽  
Gram Negative ◽  
Reticulate Body

Cell walls of the both types of bodies, mature elementary body(EB) and developmental reticulate body(RB) of Chlamydia psittaci appear the triple layered membrane in thin section. However, in the preparations shadowcast or stained negatively EB cell wall shows hexagonally arrayed structure composed of subunits, 180A in diameter on the inside surface, whereas RB cell wall does not have this structure. Chemical analysis demonstrated that EB cell wall contained a similar amino acid composition with the cell walls of gram-negative bacteria, such as E.coli. The bactericidal effect of polymixin group against gram-negative bacilli is understood that the drug affects to the cell wall and destroys its osmotic regulation. Electron microscopy on the effects of the drug against the gram-negative bacteria revealed the formation of numerous number of projections on the cell wall surface and leakage of cell content through the projections. The present report is concerned with further studies on the fine structure of EB cell walls based on the observation on their response to polymixin B sulfate.

scholarly journals Expanding the Use of a Fluorogenic Method to Determine Activity and Mode of Action ofBacillus thuringiensisBacteriocins Against Gram-Positive and Gram-Negative Bacteria

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Norma M. de la Fuente-Salcido ◽  
J. Eleazar Barboza-Corona ◽  
A. N. Espino Monzón ◽  
R. D. Pacheco Cano ◽  
N. Balagurusamy ◽  
...  
Keyword(s):  
Shigella Flexneri ◽  
Correlation Coefficients ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Proteus Vulgaris ◽  
Gram Positive ◽  
Gram Negative ◽  
Clinically Significant ◽  
Mexican Strains ◽  
Crucial Parameter

Previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by Mexican strains ofBacillus thuringiensisagainstB. cereus183. Here we standardize this method to efficiently determine the activity of bacteriocins against both Gram-positive and Gram-negative bacteria. It was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is,~4 × 108 cell/mL and~7 × 108 cell/mL, respectively, for target Gram-positive and Gram-negative bacteria. Comparative analyses of the fluorogenic and traditional well-diffusion assays showed correlation coefficients of 0.88 to 0.99 and 0.83 to 0.99, respectively, for Gram-positive and Gram-negative bacteria. The fluorogenic method demonstrated that the five bacteriocins ofB. thuringiensishave bacteriolytic and bacteriostatic activities against all microorganisms tested, including clinically significant bacteria such asListeria monocytogenes, Proteus vulgaris,andShigella flexnerireported previously to be resistant to the antimicrobials as determined using the well-diffusion protocol. These results demonstrate that the fluorogenic assay is a more sensitive, reliable, and rapid method when compared with the well-diffusion method and can easily be adapted in screening protocols for bacteriocin production by other microorganisms.

scholarly journals Combined Systems Approaches Reveal a Multistage Mode of Action of a Marine Antimicrobial Peptide against Pathogenic Escherichia coli and Its Protective Effect against Bacterial Peritonitis and Endotoxemia

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Xiumin Wang ◽  
Da Teng ◽  
Ruoyu Mao ◽  
Na Yang ◽  
Ya Hao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Plasma Membrane ◽  
Mode Of Action ◽  
Chromatin Condensation ◽  
Cell Formation ◽  
Gram Negative Bacteria ◽  
Necrosis Factor Alpha ◽  
Gram Negative ◽  
Content Type ◽  
Bacterial Peritonitis

ABSTRACTA marine arenicin-3 derivative, N4, displayed potent antibacterial activity against Gram-negative bacteria, but its antibacterial mode of action remains elusive. The mechanism of action of N4 against pathogenicEscherichia coliwas first researched by combined cytological and transcriptomic techniques in this study. The N4 peptide permeabilized the outer membrane within 1 min, disrupted the plasma membrane after 0.5 h, and localized in the cytoplasm within 5 min. Gel retardation and circular dichroism (CD) spectrum analyses demonstrated that N4 bound specifically to DNA and disrupted the DNA conformation from the B type to the C type. N4 inhibited 21.1% of the DNA and 20.6% of the RNA synthesis within 15 min. Several hallmarks of apoptosis-like cell death were exhibited by N4-inducedE. coli, such as cell cycle arrest in the replication (R) and division(D) phases, reactive oxygen species production, depolarization of the plasma membrane potential, and chromatin condensation within 0.5 h. Deformed cell morphology, disappearance of the plasma membrane, leakage of the contents, and ghost cell formation were demonstrated by transmission electron microscopy, and nearly 100% of the bacteria were killed by N4. A total of 428 to 663 differentially expressed genes are involved in the response to N4, which are associated mainly with membrane biogenesis (53.9% to 56.7%) and DNA binding (13.3% to 14.9%). N4-protected mice that were lethally challenged with lipopolysaccharide (LPS) exhibited reduced levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNF-α) in serum and protected the lungs from LPS-induced injury. These data facilitate an enhanced understanding of the mechanisms of marine antimicrobial peptides (AMPs) against Gram-negative bacteria and provide guidelines in developing and applying novel multitarget AMPs in the field of unlimited marine resources as therapeutics.

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