scholarly journals The Mannose-Sensitive Hemagglutinin ofVibrio cholerae Promotes Adherence to Zooplankton

2001 ◽  
Vol 67 (7) ◽  
pp. 3220-3225 ◽  
Author(s):  
Deborah A. Chiavelli ◽  
Jane W. Marsh ◽  
Ronald K. Taylor
Keyword(s):  
Vibrio Cholerae ◽  
Potential Role ◽  
Daphnia Pulex ◽  
The Other ◽  
Etiological Agent ◽  
Aquatic Habitats ◽  
Environmental Persistence ◽  
Specific Manner ◽  
El Tor

ABSTRACT The bacterium Vibrio cholerae, the etiological agent of cholera, is often found attached to plankton, a property that is thought to contribute to its environmental persistence in aquatic habitats. The V. cholerae O1 El Tor biotype andV. cholerae O139 strains produce a surface pilus termed the mannose-sensitive hemagglutinin (MSHA), whereas V. cholerae O1 classical biotype strains do not. AlthoughV. cholerae O1 classical does not elaborate MSHA, the gene is present and expressed at a level comparable to that of the other strains. Since V. cholerae O1 El Tor and V. cholerae O139 have displaced V. cholerae O1 classical as the major epidemic strains over the last fifteen years, we investigated the potential role of MSHA in mediating adherence to plankton. We found that mutation of mshA in V. cholerae O1 El Tor significantly diminished, but did not eliminate, adherence to exoskeletons of the planktonic crustaceanDaphnia pulex. The effect of the mutation was more pronounced for V. cholerae O139, essentially eliminating adherence. Adherence of the V. cholerae O1 classicalmshA mutant was unaffected. The results suggest that MSHA is a factor contributing to the ability of V. cholerae to adhere to plankton. The results also showed that both biotypes of V. cholerae O1 utilize factors in addition to MSHA for zooplankton adherence. The expression of MSHA and these additional, yet to be defined, adherence factors differ in a serogroup- and biotype-specific manner.

scholarly journals Long-Read-Based Genome Sequences of Pandemic and Environmental Vibrio cholerae Strains

2018 ◽  
Vol 7 (23) ◽  
Author(s):  
Noémie Matthey ◽  
Natália C. Drebes Dörr ◽  
Melanie Blokesch
Keyword(s):  
Vibrio Cholerae ◽  
Human Disease ◽  
The Other ◽  
Etiological Agent ◽  
Genome Sequences ◽  
Environmental Strain ◽  
Content Type ◽  
Aquatic Bacterium ◽  
Long Read ◽  
El Tor

The bacterium Vibrio cholerae exhibits two distinct lifestyles, one as an aquatic bacterium and the other as the etiological agent of the pandemic human disease cholera. Here, we report closed genome sequences of two seventh pandemic V. cholerae O1 El Tor strains, A1552 and N16961, and the environmental strain Sa5Y.

Cercarial swimming performance and its potential role as a key variable of trematode transmission

Parasitology ◽  
2020 ◽  
Vol 147 (12) ◽  
pp. 1369-1374 ◽  
Author(s):  
Neil J. Morley
Keyword(s):  
Swimming Speed ◽  
Potential Role ◽  
Swimming Performance ◽  
Tail Length ◽  
Host Searching ◽  
Aquatic Habitats ◽  
Searching Behaviour ◽  
Biological Variables ◽  
Using Data

AbstractTrematode transmission in aquatic habitats from molluscan intermediate host to vertebrate or invertebrate target host is typically undertaken by a free-living stage known as cercariae. Active locomotion by cercariae is a key aspect of the transmission process with the swimming speed potentially contributing to infection success. Individual cercarial species swim at different speeds but the significance of this to infection potential has not been determined. This study, using data from the scientific literature, investigates the role of swimming speed in relation to cercarial morphology, host-searching strategies and target host species. Larger cercariae swim faster than smaller ones with tail length being the principal factor controlling locomotion rates. Different cercarial morphotypes swim at different speeds, in particular, furcocercariae, with the exception of the schistosomes, being faster swimmers than mono-tailed cercariae. Host-searching behaviour has a significant influence on swimming speeds with ‘active-searching’ strategies swimming slower than those adopting ‘active-waiting’ or ‘prey mimcry’ strategies. Vertebrate-infecting cercariae swim faster than those infecting invertebrates with species targeting fish demonstrating the highest locomotion rates and those targeting arthropods the slowest speeds. The adaptions of individual cercarial swimming speeds to biological variables and their interactions with the physical processes of aquatic habitats are discussed.

scholarly journals The Grand Challenge of Corporate Control: Opening strategy to the normative pressures of networked professionals

2020 ◽  
Vol 1 (4) ◽  
pp. 263178772096969
Author(s):  
Richard Whittington ◽  
Basak Yakis-Douglas
Keyword(s):  
Potential Role ◽  
Corporate Control ◽  
Labour Markets ◽  
The Other ◽  
Grand Challenge ◽  
Big Business ◽  
Research Themes ◽  
The One ◽  
Open Strategy

We propose that the pre-eminent ‘grand challenge’ for organization theorists today is the societal control of powerful corporations. This grand challenge is the more urgent because of the contemporary inadequacies of markets, hierarchies and regulations as instruments of control. We argue for the potential role of ‘open strategy’ in mobilizing normative controls over big business. We develop a distinction between the managed and unmanaged practices of open strategy. Both can help expose corporations to normative pressures, but we highlight the unmanaged open practices of collective subpolitics and individualist whistleblowing. Especially when mobilized by globally networked professionals, these unmanaged practices can subject corporations to normative pressures where markets, hierarchies and regulations fail. We propose two broad research themes relevant to the effectiveness of managed and unmanaged practices of strategic openness: on the one hand, there are material issues to do with labour markets, organizing and technologies; on the other hand, there are discursive questions of authenticity, capability and identity.

Preliminary Studies on Bemitradine-Induced Cardiotoxicity in Female Rats

1991 ◽  
Vol 10 (5) ◽  
pp. 511-523 ◽  
Author(s):  
S. Levin ◽  
D. Semler ◽  
S. Gad ◽  
E. Burton ◽  
G. Walsh ◽  
...  
Keyword(s):  
Potential Role ◽  
The Other ◽  
Female Rats ◽  
Separate Experiment ◽  
Direct Effects ◽  
Primary Metabolite ◽  
T Wave ◽  
Mixed Function Oxidases ◽  
Circulating Levels

The mechanism of bemitradine (SC-33643) cardiotoxicity in female rats was investigated in the set of preliminary experiments reported here. Specifically, the involvement of bemitradine metabolites and the potential role of adrenal epinephrine release were examined. Desethylbemi-tradine (the primary metabolite of bemitradine) was shown to be cardiotoxic at oral dosages greater than 300 mg/kg for 7 days. In a separate experiment, a major metabolite (bemitradine glycol) unique to the rat was not cardiotoxic at dosages up to 600 mg/kg for 7 days. Treatment of rats with SKF 525-A enhanced the lethality and the cardiotoxicity of bemitradine. In contrast, prior treatments of rats with phenobarbital resulted in decreased cardiotoxicity of both bemitradine and desethylbemitradine (a bemitradine metabolite presumably further metabolized by the microsomal mixed function oxidases). In other independent experiments, bemitradine-induced cardiotoxicity was shown to be accompanied by adrenal damage and decreases in adrenal epinephrine. Propranolol (a β-antagonist) treatment protected rats against cardiotoxicity. Bemitradine also had a direct effect on the heart, as evidenced in an experiment in which bemitradine caused dose-related increases in the T-wave of the rat ECG complex. These data suggest that (1) both bemitradine and desethylbemitradine may be responsible for the cardiotoxicity, and the other downstream metabolites are not and (2) cardiotoxicity may be due to the combination of direct effects of bemitradine on the rat heart and the bemitradine-mediated release of adrenal epinephrine (a known cardiotoxin at high circulating levels).

scholarly journals Mask-Induced Priming and the Negative Compatibility Effect

2008 ◽  
Vol 55 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Petroc Sumner
Keyword(s):  
Opposite Direction ◽  
Compatibility Effect ◽  
Alternative Explanation ◽  
Potential Role ◽  
The Other ◽  
Motor Inhibition ◽  
Positive Priming ◽  
Motor Activation ◽  
Random Line

Abstract. Under certain conditions, masked primes have produced counter-intuitive negative compatibility effects (NCE), such that RT is increased, not decreased, when the target is similar to the prime. This NCE has been interpreted as an index of automatic motor inhibition, triggered to suppress the partial motor activation caused by the prime. An alternative explanation is that perceptual interactions between prime and mask produce positive priming in the opposite direction to the prime, explaining the NCE without postulating inhibition. Here the potential role of this “mask-induced priming” was investigated in two experiments, using masks composed of random lines. Experiment 1 compared masks that included features of the primes and targets with masks that did not. The former should create more mask-induced priming, but the NCE did not differ between masks. Experiment 2 employed masks that contained features of either one target or the other, but not both. These asymmetric masks produced significant mask-induced priming, but it was insufficient in size to account for the prime-related NCE. Thus mask composition can contribute to NCEs, but when random line masks are employed, the major source of the NCE seems to be motor-inhibition.

Emergence of New ALK Mutations at Relapse of Neuroblastoma

2014 ◽  
Vol 32 (25) ◽  
pp. 2727-2734 ◽  
Author(s):  
Gudrun Schleiermacher ◽  
Niloufar Javanmardi ◽  
Virginie Bernard ◽  
Quentin Leroy ◽  
Julie Cappo ◽  
...  
Keyword(s):  
Deep Sequencing ◽  
Sanger Sequencing ◽  
Potential Role ◽  
Clonal Evolution ◽  
Point Mutations ◽  
The Other ◽  
Therapeutic Decisions ◽  
Primary Sample ◽  
A Minor

Purpose In neuroblastoma, the ALK receptor tyrosine kinase is activated by point mutations. We investigated the potential role of ALK mutations in neuroblastoma clonal evolution. Methods We analyzed ALK mutations in 54 paired diagnosis–relapse neuroblastoma samples using Sanger sequencing. When an ALK mutation was observed in one paired sample, a minor mutated component in the other sample was searched for by more than 100,000× deep sequencing of the relevant hotspot, with a sensitivity of 0.17%. Results All nine ALK-mutated cases at diagnosis demonstrated the same mutation at relapse, in one case in only one of several relapse nodules. In five additional cases, the mutation seemed to be relapse specific, four of which were investigated by deep sequencing. In two cases, no mutation evidence was observed at diagnosis. In one case, the mutation was present at a subclonal level (0.798%) at diagnosis, whereas in another case, two different mutations resulting in identical amino acid changes were detected, one only at diagnosis and the other only at relapse. Further evidence of clonal evolution of ALK-mutated cells was provided by establishment of a fully ALK-mutated cell line from a primary sample with an ALK-mutated cell population at subclonal level (6.6%). Conclusion In neuroblastoma, subclonal ALK mutations can be present at diagnosis with subsequent clonal expansion at relapse. Given the potential of ALK-targeted therapy, the significant spatiotemporal variation of ALK mutations is of utmost importance, highlighting the potential of deep sequencing for detection of subclonal mutations with a sensitivity 100-fold that of Sanger sequencing and the importance of serial samplings for therapeutic decisions.

The role of toxin-coregulated pili in experimental infection by Vibrio cholerae strains of El Tor biotype

Vaccine ◽  
1992 ◽  
Vol 10 (4) ◽  
pp. 287
Author(s):  
Elena Voss ◽  
P.A. Manning ◽  
S.R. Attridge
Keyword(s):  
Vibrio Cholerae ◽  
Experimental Infection ◽  
El Tor

scholarly journals The Vibrio cholerae Mannose-Sensitive Hemagglutinin Is the Receptor for a Filamentous Bacteriophage from V. cholerae O139

1998 ◽  
Vol 66 (6) ◽  
pp. 2535-2539 ◽  
Author(s):  
Elena A. Jouravleva ◽  
Gregory A. McDonald ◽  
Jane W. Marsh ◽  
Ronald K. Taylor ◽  
Mary Boesman-Finkelstein ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Deletion Mutants ◽  
Type Iv ◽  
Phage Dna ◽  
Infection Susceptibility ◽  
Resistance To Infection ◽  
Pilin Gene ◽  
El Tor ◽  
Susceptibility And Resistance

ABSTRACT We previously isolated from a 1994 isolate of Vibrio cholerae O139 a filamentous lysogenic bacteriophage, choleraphage 493, which inhibits pre-O139 but not post-O139 El Tor biotype V. cholerae strains in plaque assays. We investigated the role of the mannose-sensitive hemagglutinin (MSHA) type IV pilus as a receptor in phage 493 infection. Spontaneous, Tn5 insertion, andmshA deletion mutants are resistant to 493 infection. Susceptibility is restored by mshA complementation of deletion mutants. Additionally, the 493 phage titer is reduced by adsorption with MSHA-positive strains but not with a ΔmshA1 strain. Monoclonal antibody against MSHA inhibits plaque formation. We conclude that MSHA is the receptor for phage 493. The emergence and decline of O139 in India and Bangladesh are correlated with the susceptibility and resistance of El Tor strains to 493. However, mshA gene sequences of post-O139 strains are identical to those of susceptible pre-O139 isolates, indicating that phage resistance of El Tor is not due to a change in mshA. Classical biotype strains are (with rare exceptions) hemagglutinin negative and resistant to 493 in plaque assays. Nevertheless, they express the mshA pilin gene. They can be infected with 493 and produce low levels of phage DNA, like post-O139 El Tor strains. Resistance to 493 in plaque assays is thus not equivalent to resistance to infection. The ability of filamentous phages, such as 493, to transfer large amounts of DNA provides them, additionally, with the potential for quantum leaps in both identity and pathogenicity, such as the conversion of El Tor to O139.

scholarly journals Frequency of Vibrio cholerae in the Water and Plankton Samples of South- Western Coastal Aquatic Habitats of Bangladesh

2012 ◽  
Vol 36 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Md Mansurul Haque ◽  
Munirul Alam ◽  
Abdus Salam
Keyword(s):  
Vibrio Cholerae ◽  
Culture Media ◽  
The Other ◽  
Environmental Surveillance ◽  
Aquatic Habitats ◽  
Culture Methods ◽  
Counting Technique ◽  
Other Hand ◽  
Investigation Period ◽  
Academy Of Sciences

Monthly environmental surveillance was carried out for three consecutive years in the coastal aquatic habitats of Mathbaria, with a view to assessing the culturability and abundance of V. cholerae. The study revealed that 93 samples (29%) out of 324 were positive for V. cholerae O1 on TCBS and TTGA culture media but no sample was found positive for V. cholerae O139 in the same culture media. On the other hand, all the water and plankton samples were found positive for V. cholerae O1 and O139 in DFA counting technique. Similarly, V. cholerae non-O1 and non- O139 were detected from all samples through culture methods throughout the investigation period.   V. cholerae O139 has been found to be absolutely non-responsive to artificial enrichment and culture media with the advancement of time. Therefore, water and plankton samples can also be concluded to be the additional reservoir of V. cholerae DOI: http://dx.doi.org/10.3329/jbas.v36i1.10922 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 1, 71-78, 2012

Sign in / Sign up

Export Citation Format

Share Document