Resuscitating Factors for Nonculturable Cells .................................... and N. N. Skorlupkina

2016 ◽  
pp. 355-362
Keyword(s):  
Nonculturable Cells

Morphological and Physiological Responses of Campylobacter jejuni to Stress

2006 ◽  
Vol 69 (11) ◽  
pp. 2747-2753 ◽  
Author(s):  
PUSSADEE TANGWATCHARIN ◽  
SUGANYA CHANTHACHUM ◽  
PRAPAPORN KHOPAIBOOL ◽  
MANSEL W. GRIFFITHS
Keyword(s):  
Campylobacter Jejuni ◽  
Viable Count ◽  
Cell Suspensions ◽  
Evolutionary Strategy ◽  
Transmission Electron ◽  
Proteomic Study ◽  
Nonculturable Cells ◽  
Plate Counts ◽  
Stressed Cell ◽  
Aging Cell

Under conditions of stress, cells of Campylobacter assume a coccoid shape that may be an evolutionary strategy evolved by the organism to enable survival between hosts. However, the physiology of Campylobacter as it devolves from spiral to coccoid-shaped morphology is poorly understood. In this study, conditions influencing the survival of Campylobacter jejuni ATCC 35921 in broth were determined. Cells in late log phase were resuspended in broth at 4 or 60°C. The culturability of these cold- or heat-stressed cell suspensions was determined by spread plate counts and the activity of cells by the direct viable count technique and 5-cyano-2,3-ditolyltetrazolium chloride staining. C. jejuni changed form completely from culturable to viable but nonculturable cells (VBNC) within 25 days at 4°C, and 15 min at 60°C. Light microscopy of C. jejuni VBNC cells showed that the spiral-shaped cells became coccoid, and transmission electron microscopy of C. jejuni VBNC cells showed that the outer membrane was lost in aging cell suspensions. Furthermore, a limited proteomic study was carried out to compare C. jejuni proteins that exhibited increased or decreased synthesis on exposure to 60°C.

scholarly journals Probiotic Bacteria May Become Dormant during Storage

2005 ◽  
Vol 71 (3) ◽  
pp. 1662-1663 ◽  
Author(s):  
Sampo J. Lahtinen ◽  
Miguel Gueimonde ◽  
Arthur C. Ouwehand ◽  
Johanna P. Reinikainen ◽  
Seppo J. Salminen
Keyword(s):  
Cell Membrane ◽  
Clinical Significance ◽  
Probiotic Bacteria ◽  
Bacterial Viability ◽  
Viable Cells ◽  
Nonculturable Cells

ABSTRACT The determination of bacterial viability in probiotic products is of economic, technological, and clinical significance. We compared four methods to enumerate three Bifidobacterium strains in fermented oat products during storage. A subpopulation of nonculturable cells retained a functional cell membrane typical of viable cells, indicating that probiotic bacteria become dormant during storage.

SIGNIFICANCE OF VIABLE BUT NONCULTURABLE BACTERIA FOR SAFETY OF FOOD PRODUCTS

2019 ◽  
Vol 1 (2) ◽  
pp. 183-189
Author(s):  
A. M. Abdullaeva ◽  
◽  
L. P. Blinkova ◽  
Yu. D. Pakhomov ◽  
◽  
...  
Keyword(s):  
Food Products ◽  
Active State ◽  
Insufficient Data ◽  
Main Hypothesis ◽  
Viable But Nonculturable ◽  
Nonculturable Cells

In this review data on hazardous influence of nonculturable cells of pathogens on humans and animals, of contamination of foodstuffs is presented and also attention is stressed on properties of such cells and their effect through foodstuffs on humans and animals. Main hypothesis of formation and resuscitation of viable but nonculturable cells are elucidated. Factors that influence shifting bacteria to nonculturability and their conversion into active state are discussed. The conclusion is drawn about biohazard of viable nonculturable cells and insufficient data about their physiology and mechanisms of transition into this state and resuscitation back.

scholarly journals Poly-3-Hydroxybutyrate in Legionella pneumophila, an Energy Source for Survival in Low-Nutrient Environments

1999 ◽  
Vol 65 (2) ◽  
pp. 822-827 ◽  
Author(s):  
Brian W. James ◽  
W. Stuart Mauchline ◽  
P. Julian Dennis ◽  
C. William Keevil ◽  
Robin Wait
Keyword(s):  
Legionella Pneumophila ◽  
Tap Water ◽  
Water Environment ◽  
Nile Red ◽  
Dry Weight ◽  
Gas Chromatography Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Term Survival ◽  
Reliable Determination ◽  
Nonculturable Cells

ABSTRACT Chloroform-soluble material was extracted from two strains ofL. pneumophila serogroup 1 following growth in continuous culture. The purified material was identified as poly-3-hydroxybutyrate (PHB) by nuclear magnetic resonance spectroscopy and by gas chromatography-mass spectrometry. PHB yields of up to 16% of cell dry weight were extracted from culture samples. The PHB was located in electron-dense intracellular inclusions, which fluoresced bright yellow when stained with the lipophilic dye Nile red. A Nile red spectrofluorometric assay provided a more accurate and reliable determination of the PHB content. PHB accumulation increased threefold during iron-limited culture and was inversely related to the concentration of iron metabolized. Chemostat-grown cells survived in a culturable state for at least 600 days when incubated at 24°C in a low-nutrient tap water environment. Nile red spectrofluorometry and flow cytometry demonstrated that PHB reserves were utilized during starvation. PHB utilization, as revealed by the decline in mean cellular fluorescence and cell complexity, correlated with loss of culturability. Fluorescence microscopy provided visual evidence of PHB utilization, with a marked reduction in the number of Nile red-stained granules during starvation. Heat shock treatment failed to resuscitate nonculturable cells. This study demonstrates that L. pneumophila accumulates significant intracellular reserves of PHB, which promote its long-term survival under conditions of starvation.

scholarly journals Microbial Scout Hypothesis, Stochastic Exit from Dormancy, and the Nature of Slow Growers

2012 ◽  
Vol 78 (9) ◽  
pp. 3221-3228 ◽  
Author(s):  
S. Buerger ◽  
A. Spoering ◽  
E. Gavrish ◽  
C. Leslin ◽  
L. Ling ◽  
...  
Keyword(s):  
Central Element ◽  
Low Frequency ◽  
Adaptive Mutation ◽  
Lag Phase ◽  
Content Type ◽  
Microbial Life ◽  
Delayed Initiation ◽  
Nonculturable Cells ◽  
Visible Growth ◽  
Species Specific

ABSTRACTWe recently proposed a scout model of the microbial life cycle (S. S. Epstein, Nature 457:1083, 2009), the central element of which is the hypothesis that dormant microbial cells wake up into active (so-called scout) cells stochastically, independently of environmental cues. Here, we check the principal prediction of this hypothesis: under growth-permissive conditions, dormant cells initiate growth at random time intervals and exhibit no species-specific lag phase. We show that a range of microorganisms, including environmental species,Escherichia coli, andMycobacterium smegmatis, indeed wake up in a seemingly stochastic manner and independently of environmental conditions, even in the longest incubations conducted (months to years long). As is implicit in the model, most of the cultures we obtained after long incubations were not inherently slow growers. Of the environmental isolates that required ≥7 months to form visible growth, only 5% needed an equally long incubation upon subculturing, with the majority exhibiting regrowth within 24 to 48 h. This apparent change was not a result of adaptive mutation; rather, most microbial species that appear to be slow growers were in fact fast growers with a delayed initiation of division. Genuine slow growth thus appears to be less significant than previously believed. Random, low-frequency exit from the nongrowing state may be a key element of a general microbial survival strategy, and the phylogenetic breadth of the organisms exhibiting such exit indicates that it represents a general phenomenon. The stochasticity of awakening can also provide a parsimonious explanation to several microbiological observations, including the apparent randomness of latent infections and the existence of viable-but-nonculturable cells (VBNC).

scholarly journals Respective Roles of Culturable and Viable-but-Nonculturable Cells in the Heterogeneity of Salmonella enterica Serovar Typhimurium Invasiveness

2009 ◽  
Vol 75 (16) ◽  
pp. 5179-5185 ◽  
Author(s):  
Julien Passerat ◽  
Patrice Got ◽  
Sam Dukan ◽  
Patrick Monfort
Keyword(s):  
Stationary Phase ◽  
Salmonella Enterica ◽  
Gradient Centrifugation ◽  
Health Concern ◽  
Viable But Nonculturable ◽  
Serovar Typhimurium ◽  
Nonculturable Cells ◽  
Sources Of Infection ◽  
Culturable Cell ◽  
Vbnc Cell

ABSTRACT The existence of Salmonella enterica serovar Typhimurium viable-but-nonculturable (VBNC) cells is a public health concern since they could constitute unrecognized sources of infection if they retain their pathogenicity. To date, many studies have addressed the ability of S. Typhimurium VBNC cells to remain infectious, but their conclusions are conflicting. An assumption could explain these conflicting results. It has been proposed that infectivity could be retained only temporarily after entry into the VBNC state and that most VBNC cells generated under intense stress could exceed the stage where they are still infectious. Using a Radioselectan density gradient centrifugation technique makes it possible to increase the VBNC-cell/culturable-cell ratio without increasing the exposure to stress and, consequently, to work with a larger proportion of newly VBNC cells. Here, we observed that (i) in the stationary phase, the S. Typhimurium population comprised three distinct subpopulations at 10, 24, or 48 h of culture; (ii) the VBNC cells were detected at 24 and 48 h; (iii) measurement of invasion gene (hilA, invF, and orgA) expression demonstrated that cells are highly heterogeneous within a culturable population; and (iv) invasion assays of HeLa cells showed that culturable cells from the different subpopulations do not display the same invasiveness. The results also suggest that newly formed VBNC cells are either weakly able or not able to successfully initiate epithelial cell invasion. Finally, we propose that at entry into the stationary phase, invasiveness may be one way for populations of S. Typhimurium to escape stochastic alteration leading to cell death.

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