Identification of Intracellular Polysaccharide Granules in Thin Sections of Nocardia asteroides

DiPersio, Joseph R.; Deal, S. J.

doi:10.1099/00221287-83-2-349

Cited by 21 publications

(9 citation statements)

References 9 publications

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“…Sections were treated with 1% aqueous periodic acid for 30 min, washed and then treated with sodium chlorite prepared in acetic acid and water as previously described [54]. Periodic acid exposure was omitted in control experiments [54], [55].…”

Section: Methodsmentioning

confidence: 99%

Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

Li²,

Gunawardana

et al. 2014

PLoS ONE

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Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended.

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Section: Methodsmentioning

confidence: 99%

Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

Li²,

Gunawardana

et al. 2014

PLoS ONE

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“…The IPS produced by B. fragilis is located intracellularly, as it is in streptococci (Gibbons & Kapsimalis, 1963). In electron micrographs, the IPS of B. fragilis was observed as cytoplasmic granules, as in E. coli (Cedergren & Holme, 1959), Streptococcus mutans and Nocardia asteroides (DiPersio & Deal, 1974).…”

Section: Discussionmentioning

confidence: 95%

Intracellular Polysaccharide of Bacteroides fragilis

Lindnery

Marcelis

Vos

et al. 1979

Journal of General Microbiology

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Formation of iodophilic polysaccharide (IPS) from glucose was demonstrated in 27 strains of Bacteroides fragilis. Synthesis was dependent on the glucose concentration of the medium, the pH and the growth phase. When glucose was in short supply the cellular polysaccharide was degraded rapidly at pH 4-5 to 6.5 and fatty acids accumulated in the medium. Storage of IPS was not responsible for the low carbon recoveries observed in fermentation balance studies. In electron micrographs of thin sections, the IPS was observed as cytoplasmic granules dispersed throughout the whole cell. After extraction and purification the IPS was characterized as a glycogen.

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“…Glycogen is a common reserve material among eukaryotes and eubacteria [1][2][3][4][5][6][7][8][9] and it was also found in thermoacidophilic archaebacteria [10].…”

Section: Introductionmentioning

confidence: 99%

Glycogen in Methanolobus and Methanococcus

König

1985

FEMS Microbiology Letters

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Glycogen was isolated from Methanolobus tindarius and 4 species of Methanococcus. It was identified by the iodine reaction, determination of glucose, maltose and isomaltose in acid hydrolysates and partial acid hydrolysates, respectively, determination of erythritol and glycerol after periodate oxidation and treatment with amyloglucosidase. Glycogen particles in the cells are distributed throughout the cytoplasm. Ml. tindarius can use elemental nitrogen and cysteine as nitrogen source. The glycogen and polyphosphate content of cells of Ml. tindarius increased under nitrogen limitation. During incubation without external energy source, glycogen decreased and methane formation was correlated to the glycogen content of the cells.

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Identification of Intracellular Polysaccharide Granules in Thin Sections of Nocardia asteroides

Cited by 21 publications

References 9 publications

Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

Intracellular Polysaccharide of Bacteroides fragilis

Glycogen in Methanolobus and Methanococcus

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