Spheroplast formation by an anaerobic gram-negative bacterium Bacteroides ruminicola

1973 ◽  
Vol 19 (5) ◽  
pp. 667-669 ◽  
Author(s):  
K. -J. Cheng
Keyword(s):  
Stationary Phase ◽  
Rumen Fluid ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Fluid Medium ◽  
Gram Negative ◽  
Spontaneous Formation

The spontaneous formation of spheroplasts was observed in stationary phase cultures and in aging cultures of Bacteroides ruminicola when grown in synthetic or a rumen fluid medium. Unlike most other gram-negative bacteria, spheroplasts of this organism also were formed when log-phase cells were treated with lysozyme in the presence of 0.01 M Mg2+ in 0.01 M Tris, pH 8.4.

Fusobacterium nucleatum, the first Gram-negative bacterium demonstrated to produce polyglutamate

2009 ◽  
Vol 55 (5) ◽  
pp. 627-632 ◽  
Author(s):  
Thomas Candela ◽  
Marie Moya ◽  
Michel Haustant ◽  
Agnès Fouet
Keyword(s):  
In Silico Analysis ◽  
Fusobacterium Nucleatum ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
The Third ◽  
Gram Negative Organisms ◽  
First Time

Poly-γ-glutamate has been described in many Gram-positive organisms. When anchored to the surface, it is a capsule and as such a virulence factor. Based on sequence similarities, few Gram-negative organisms have been suggested to synthesize poly-γ-glutamate. For the first time, a Gram-negative bacterium, Fusobacterium nucleatum , is shown to produce and secrete poly-γ-glutamate. Putative poly-γ-glutamate-synthesizing genes from Gram-negative organisms have been compared with their Gram-positive homologs by in silico analysis, i.e., gene sequence and phylogenetic analysis. Clusters of three instead of four genes were highlighted by our screen. The products of the first two genes display similarity with their Gram-positive equivalents, yet the sequences from the Gram-negative organisms can be distinguished from those of the Gram-positives. Interestingly, the sequence of the predicted product of the third gene is conserved among Gram-negative bacteria but displays no similarity to that of either the third or fourth gene of the Gram-positive operons. It is suggested that, like for Gram-positive bacteria, poly-γ-glutamate has a role in virulence for pathogens and one in survival for other Gram-negative bacteria.

scholarly journals Stationary phase in gram-negative bacteria

2010 ◽  
Vol 34 (4) ◽  
pp. 476-495 ◽  
Author(s):  
Juana María Navarro Llorens ◽  
Antonio Tormo ◽  
Esteban Martínez-García
Keyword(s):  
Stationary Phase ◽  
Gram Negative Bacteria ◽  
Gram Negative

Heterogeneity of Surfaces of Subgingival Bacteria as Detected by Zeta Potential Measurements

1992 ◽  
Vol 71 (11) ◽  
pp. 1803-1806 ◽  
Author(s):  
M.M. Cowan ◽  
H.C. Van der Mei ◽  
I. Stokroos ◽  
H.J. Busscher
Keyword(s):  
Ph Dependence ◽  
Laboratory Strain ◽  
Prevotella Intermedia ◽  
Gram Negative Bacteria ◽  
Cell Surfaces ◽  
Fluid Medium ◽  
Gram Negative ◽  
Zeta Potentials ◽  
Ph Values ◽  
Ph Dependent

Porphyromonasgingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans (A.a.) are Gram-negative bacteria which are implicated in various forms of periodontal disease. The Gram-positive Peptostreptococcus micros may also play an important role. For investigation of the possible adhesion and colonization mechanisms of these organisms, the charge properties of the outermost layers of bacterial cell surfaces were studied through the measurement of zeta potentials at various pH values. Eleven fresh clinical isolates, representing the four species, and one laboratory strain, P. gingivalis W83, were examined. Eleven of the 12 strains displayed heterogeneity with respect to pH-dependent zeta potentials. Within single cultures of each of these strains, two distinct populations of cells were found, one which was more negatively charged than the other. For the Gram-negative strains, the more negatively charged subpopulation was in the majority, while the P. micros strains appeared to be composed mainly of a less-negatively-charged subpopulation. Vesicles prepared from two strains displayed the same pH dependence and heterogeneity of zeta potentials as the parent cells. An A.a. strain which was passaged several times in fluid medium had lost its fimbriae and became homogeneous with respect to charge.

Endotoxic activity of cell-free rumen fluid from cattle fed hay or grain

1978 ◽  
Vol 24 (10) ◽  
pp. 1253-1261 ◽  
Author(s):  
T. G. Nagaraja ◽  
L. R. Fina ◽  
E. E. Bartley ◽  
H. D. Anthony
Keyword(s):  
Actinomycin D ◽  
Rumen Fluid ◽  
Quantitative Difference ◽  
Gram Negative Bacteria ◽  
Chick Embryos ◽  
Ether Extract ◽  
Gram Negative ◽  
Bacterial Endotoxins ◽  
Phenol Water ◽  
Endotoxic Activity

The cell-free rumen fluid from cattle fed hay or grain exhibited the following biological characteristics which strongly suggest the presence of endotoxin or a toxic principle similar to endotoxin of gram-negative bacteria: proved lethal to mice when injected with actinomycin D; proved extremely lethal to chick embryos: induced biphasic pyrogenic response in rabbits; enhanced susceptibility to bacterial infection in mice; evoked positive epinephrine skin reaction in rabbits and phenol–water or aqueous ether extract proved lethal to mice and chick embryos. A quantitative difference in concentrations of endotoxin was observed, based on LD50 in mice and chick embryos and response to the epinephrine skin test in rabbits. Cell-free rumen fluid of grain-fed cattle contained at least twice as much endotoxin as that of hay-fed cattle. Endotoxin in cell-free rumen fluid and in higher concentration in cattle fed grain than in those fed hay support the hypothesis that rumen bacterial endotoxins may participate in the pathogenesis of diseases associated with high grain feeding such as lactic acidosis and the sudden-death syndrome.

Phospholipids of the differentiating bacterium Caulobacter crescentus

1979 ◽  
Vol 57 (5) ◽  
pp. 424-428 ◽  
Author(s):  
Darrell E. Jones ◽  
Joseph Donald Smith
Keyword(s):  
Caulobacter Crescentus ◽  
Phospholipid Composition ◽  
Cell Types ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Cell Type ◽  
Swarmer Cell ◽  
Gram Negative ◽  
Major Phospholipid

The phospholipid composition of the stalked and swarmer cell types of the differentiating, Gram-negative bacterium Caulobacter crescentus was determined. The phospholipid composition of the stalked cell type was 86.5% phosphatidylglycerol, 10.4% lysylphosphatidylglycerol, and 3.0% cardiolipin; that of the swarmer cell type was 84.1, 11.4, and 4.4%, respectively. Phosphatidylethanolamine, which is a major phospholipid component of most Gram-negative bacteria, was totally absent.

scholarly journals Digestion of rumen bacteria in vitro

1983 ◽  
Vol 49 (1) ◽  
pp. 101-108 ◽  
Author(s):  
R. J. Wallace
Keyword(s):  
Rumen Fluid ◽  
Individual Species ◽  
Rumen Bacteria ◽  
Gram Negative Bacteria ◽  
Bacterial Protein ◽  
Gram Positive ◽  
Gram Negative ◽  
Pure Cultures ◽  
Mixed Bacteria

1. A pepsin + pancreatin method was used to assess the digestibility of pure cultures of rumen bacteria and mixed bacteria prepared from rumen fluid.2. Individual species of Gram-negative rumen bacteria were highly digestible, whereas Gram-positive species, especially cocci, were more resistant to digestion.3. A similar difference was observed microscopically with mixed rumen bacteria, but the influence of the relative proportions of Gram-positive and Gram-negative bacteria on the digestibility of bacterial protein in rumen fluid was small.

scholarly journals Spatiotemporal organization of BamA governs the pattern of outer membrane protein distribution in growing Escherichia coli cells

2021 ◽  
Author(s):  
Gideon Mamou ◽  
Patrick G. Inns ◽  
Dawei Sun ◽  
Renata Kaminska ◽  
Nicholas G. Housden ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Outer Membrane ◽  
Temporal Organization ◽  
Gram Negative Bacteria ◽  
Protein Distribution ◽  
Spatiotemporal Organization ◽  
Gram Negative ◽  
Bam Complex ◽  
K 12

AbstractThe outer membrane (OM) of Gram-negative bacteria is a robust protective barrier that excludes major classes of antibiotics. The assembly, integrity and functioning of the OM is dependent on β-barrel outer membrane proteins (OMPs), the insertion of which is catalyzed by BamA, the core component of the β-barrel assembly machine (BAM) complex. Little is known about BamA in the context of its native OM environment. Here, using high-affinity fluorescently-labelled antibodies in combination with diffraction-limited and super-resolution fluorescence microscopy, we uncover the spatial and temporal organization of BamA in live Escherichia coli K-12 cells. BamA is clustered into ~150 nm diameter islands that contain an average of 10-11 BamA molecules, in addition to other OMPs, and are distributed throughout the OM and which migrate to the poles during growth. In stationary phase cells, BamA is largely confined to the poles. Emergence from stationary phase coincides with new BamA-containing islands appearing on the longitudinal axis of cells, suggesting they are not seeded by pre-existing BamAs but initiate spontaneously. Consistent with this interpretation, BamA-catalyzed OMP biogenesis is biased towards non-polar regions. Cells ensure the capacity for OMP biogenesis is uniformly distributed during exponential growth, even if the growth rate changes, by maintaining an invariant density of BamA-containing OMP islands (~9 islands/μm2) that only diminishes as cells enter stationary phase, the latter change governing what OMPs predominate as cells become quiescent. We conclude that OMP distribution in E. coli is driven by the spatiotemporal organisation of BamA which varies with the different phases of growth.SignificanceThe integrity and functioning of the outer membrane (OM) of Gram-negative bacteria depends on the β-barrel assembly machinery (BAM). Although the structure and the mechanism of the complex have been widely explored, little information exists about the organization of the BAM complex and how it dictates protein distribution in the OM. Here, we utilized highly specific monoclonal antibodies to study the spatiotemporal organization of BamA, the key component of this complex. We reveal that BAM organization is dynamic and tightly linked to the cell’s growth phase. We further discover that the rate of BAM facilitated OMP biogenesis is significantly reduced near the poles. In turn, these features govern the biogenesis patterns and the distribution of OMPs on the cell surface.

Properties of a D-quinovosamine-producing Achromobacter

1968 ◽  
Vol 14 (2) ◽  
pp. 165-171 ◽  
Author(s):  
R. R. Colwell ◽  
E. J. Smith ◽  
G. B. Chapman
Keyword(s):  
Deoxyribonucleic Acid ◽  
Buoyant Density ◽  
Cesium Chloride ◽  
Wall Structure ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Acid Base ◽  
Gram Negative ◽  
Density Measurements ◽  
Ultrathin Sections

The bacterial mucopolysaccharide of a Gram-negative bacterium, Georgetown strain COC-21, includes a hexosamine component, D-quinovosamine. The bacterium has been identified and classified as Achromobacter georgiopolitanum n. sp. and a description of the organism is given. The overall deoxyribonucleic acid base composition, determined by buoyant density measurements in cesium chloride, is 41 moles %. Electron micrographs of ultrathin sections reveal a double-layered cell wall structure typical of the Gram-negative bacteria.

scholarly journals Stenotrophomonas maltophilia D457R Contains a Cluster of Genes from Gram-Positive Bacteria Involved in Antibiotic and Heavy Metal Resistance

2000 ◽  
Vol 44 (7) ◽  
pp. 1778-1782 ◽  
Author(s):  
Ana Alonso ◽  
Patricia Sanchez ◽  
José L. Martínez
Keyword(s):  
Heavy Metal ◽  
Stenotrophomonas Maltophilia ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT A cluster of genes involved in antibiotic and heavy metal resistance has been characterized from a clinical isolate of the gram-negative bacterium Stenotrophomonas maltophilia. These genes include a macrolide phosphotransferase (mphBM) and a cadmium efflux determinant (cadA), together with the genecadC coding for its transcriptional regulator. ThecadC cadA region is flanked by a truncated IS257 sequence and a region coding for a bin3invertase. Despite their presence in a gram-negative bacterium, these genetic elements share a common gram-positive origin. The possible origin of these determinants as a remnant composite transposon as well as the role of gene transfer between gram-positive and gram-negative bacteria for the acquisition of antibiotic resistance determinants in chronic, mixed infections is discussed.

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