Changes in the Cell Structure of <i>Flavobacterium psychrophilum</i> with Length of Culture

Kondo, Motoki; Kawai, Kenji; Yagyu, Ken-ichi; Nakayama, Kouichi; Kurohara, Kenrou; Oshima, Syun-ichirou

doi:10.1111/j.1348-0421.2001.tb01320.x

Cited by 14 publications

(11 citation statements)

References 29 publications

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“…Changes in the cell morphology of Flavobacterium psychrophilum have been noted with increased culture time (Kondo et al 2001). Alterations in the cell morphology during starvation are also of interest.…”

Section: Discussionmentioning

confidence: 93%

“…No viable bacteria could be detected by either culture counts or the live/dead kit 1 h after being placed in distilled water. Michel et al (1999) found Flavobacterium psychrophilum to be highly susceptible to osmotic changes.Changes in the cell morphology of Flavobacterium psychrophilum have been noted with increased culture time (Kondo et al 2001). Alterations in the cell morphology during starvation are also of interest.…”

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confidence: 93%

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Starvation of Flavobacterium psychrophilum in broth, stream water and distilled water

Vatsos

Thompson

Adams³

2003

Dis. Aquat. Org.

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Physical changes in Flavobacterium psychrophilum, the causative agent of rainbow trout fry syndrome (RTFS), were examined over a 19 wk period of starvation. Bacteria were maintained in either Cytophaga broth, filtered stream water, or filtered distilled water, or were maintained in broth after disinfection as a negative control for dead bacteria. Culturability and viability of the bacterium were assessed using colony-forming units (CFUs) and a commercially available live/dead kit. Antigenic profiles and general morphology of the bacterium were also examined using Western blot analysis and electron microscopy, respectively. The bacterium appeared to stop multiplying and became smaller and rounded when maintained in stream water. Its culturability declined until it was no longer possible to obtain colonies on agar plates at the end of the trial at 19 wk, and results from the live/dead kit did not correspond with the viability obtained as CFUs in culture. However, it was still possible to obtain growth of the bacterium after 36 wk with a resuscitation step in Cytophaga broth. Bacteria maintained in distilled water or treated with a disinfectant appeared non-viable using the live/dead kit and were unable to grow on agar 1 h after setting up the experiment; no morphological changes were observed in the bacteria maintained under these conditions. Bacteria maintained in broth were present as long, slim rods, some of which developed into 'ring' formations. Small differences were observed in the antigen profiles of the bacteria maintained under the different treatments, possibly due to a reduction in the size and metabolism of the bacteria. There was also a marked decline in the sensitivity of the PCR with bacteria maintained under the different treatments 14 wk from the onset of the study. KEY WORDS: Flavobacterium psychrophilum · Rainbow trout fry syndrome · Starvation · Viability · Detection Resale or republication not permitted without written consent of the publisherDis Aquat Org 56: [115][116][117][118][119][120][121][122][123][124][125][126] 2003 water column or in sediment also cannot be excluded. However, for this latter mode of transmission, F. psychrophilum must be able to survive outside the fish for an extended period of time.Flavobacterium psychrophilum is considered a very fastidious organism, and problems with the culture of the bacterium have been reported (Daskalov et al. 1999, Michel et al. 1999. Under adverse conditions, it is possible that the bacterium enters a viable but nonculturable state, as in the case of many other bacterial species, such as Salmonella sp. (Dupray et al. 1997) and Yersinia ruckeri (Thorsen et al. 1992). This characteristic results in an inability to detect the pathogen in environmental samples when culture is used as the only means of identification.The ability of Flavobacterium psychrophilum to survive under conditions of starvation was examined in this study, and changes in the organism as an adaptation to its environment are described. F. psychrophilum cells we...

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Section: Discussionmentioning

confidence: 93%

mentioning

confidence: 93%

Starvation of Flavobacterium psychrophilum in broth, stream water and distilled water

Vatsos

Thompson

Adams³

2003

Dis. Aquat. Org.

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“…Our previous study (Kondo et al 2001b) showed that this bacterium possessed outer membrane components on the cell surface of the logarithmic phase culture. Rahman et al (2002) reported the effectiveness of the outer membrane fraction of BCWD.…”

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confidence: 91%

“…In the challenge test, bacteria in the logarithmic culture phase were used because this phase showed higher virulence than other phases (Kondo et al 2001b). The results showed that vaccination by either method gave significantly higher survival rates than the control in both challenge tests.…”

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confidence: 99%

Efficacy of oral vaccine against bacterial coldwater disease in ayu Plecoglossus altivelis

Kondo

Kawai²,

Okabe³

et al. 2003

Dis. Aquat. Org.

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“…produce OM vesicles in both intraphagosomal and extraphagosomal compartments (3,33,44,45). In the case of Flavobacterium, vesicles are made late in the growth phase (82). The mechanism of vesicle production is complex (95), and progress in this field will be updated in detail in a separate review (A. Kulp and M. J. Kuehn, unpublished data).…”

Section: Natural Om Vesiclesmentioning

confidence: 99%

Virulence and Immunomodulatory Roles of Bacterial Outer Membrane Vesicles

Ellis

Kuehn

2010

Microbiol Mol Biol Rev

807

736

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SUMMARY Outer membrane (OM) vesicles are ubiquitously produced by Gram-negative bacteria during all stages of bacterial growth. OM vesicles are naturally secreted by both pathogenic and nonpathogenic bacteria. Strong experimental evidence exists to categorize OM vesicle production as a type of Gram-negative bacterial virulence factor. A growing body of data demonstrates an association of active virulence factors and toxins with vesicles, suggesting that they play a role in pathogenesis. One of the most popular and best-studied pathogenic functions for membrane vesicles is to serve as natural vehicles for the intercellular transport of virulence factors and other materials directly into host cells. The production of OM vesicles has been identified as an independent bacterial stress response pathway that is activated when bacteria encounter environmental stress, such as what might be experienced during the colonization of host tissues. Their detection in infected human tissues reinforces this theory. Various other virulence factors are also associated with OM vesicles, including adhesins and degradative enzymes. As a result, OM vesicles are heavily laden with pathogen-associated molecular patterns (PAMPs), virulence factors, and other OM components that can impact the course of infection by having toxigenic effects or by the activation of the innate immune response. However, infected hosts can also benefit from OM vesicle production by stimulating their ability to mount an effective defense. Vesicles display antigens and can elicit potent inflammatory and immune responses. In sum, OM vesicles are likely to play a significant role in the virulence of Gram-negative bacterial pathogens.

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Changes in the Cell Structure of Flavobacterium psychrophilum with Length of Culture

Cited by 14 publications

References 29 publications

Starvation of Flavobacterium psychrophilum in broth, stream water and distilled water

Starvation of Flavobacterium psychrophilum in broth, stream water and distilled water

Efficacy of oral vaccine against bacterial coldwater disease in ayu Plecoglossus altivelis

Virulence and Immunomodulatory Roles of Bacterial Outer Membrane Vesicles

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