scholarly journals Vibriophages and Their Interactions with the Fish Pathogen Vibrio anguillarum

2014 ◽  
Vol 80 (10) ◽  
pp. 3128-3140 ◽  
Author(s):  
Demeng Tan ◽  
Lone Gram ◽  
Mathias Middelboe
Keyword(s):  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
Phenotypic Properties ◽  
Content Type ◽  
Host Interaction ◽  
Individual Host ◽  
Potential Development ◽  
The Individual ◽  
Susceptibility Patterns ◽  
Rapid Regrowth

ABSTRACTVibrio anguillarumis an important pathogen in aquaculture, responsible for the disease vibriosis in many fish and invertebrate species. Disease control by antibiotics is a concern due to potential development and spread of antibiotic resistance. The use of bacteriophages to control the pathogen may offer a non-antibiotic-based approach to reduce vibriosis. A detailed understanding of the phage-host interaction is needed to evaluate the potential of phages to control the pathogen. In this study, we examined the diversity and interactions of 11 vibriophages, 24V. anguillarumstrains, and 13Vibriospecies strains. Together, the host ranges of the 11 phages covered all of the tested 37Vibriosp. host strains, which represented considerable temporal (20 years) and geographical (9 countries) differences in their origins of isolation. Thus, despite the occurrence of unique susceptibility patterns of the individual host isolates, key phenotypic properties related to phage susceptibility are distributed worldwide and maintained in the globalVibriocommunity for decades. The phage susceptibility pattern of the isolates did not show any relation to the physiological relationships obtained from Biolog GN2 profiles, demonstrating that similar phage susceptibility patterns occur across broad phylogenetic and physiological differences inVibriostrains. Subsequent culture experiments with two phages and twoV. anguillarumhosts demonstrated an initial strong lytic potential of the phages. However, rapid regrowth of both phage-resistant and phage-sensitive cells following the initial lysis suggested that several mechanisms of protection against phage infection had developed in the host populations.

scholarly journals Large Phenotypic and Genetic Diversity of Prophages Induced from the Fish Pathogen Vibrio anguillarum

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 983 ◽  
Author(s):  
Castillo ◽  
Andersen ◽  
Kalatzis ◽  
Middelboe
Keyword(s):  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
Pcr Assay ◽  
Phenotypic Properties ◽  
Specific Element ◽  
Group Iii ◽  
Multiplex Pcr Assay ◽  
Prophage Sequence ◽  
Fish And Shellfish ◽  
Efficient Transfer

Vibrio anguillarum is a marine pathogenic bacterium that causes vibriosis in fish and shellfish. Although prophage-like sequences have been predicted in V. anguillarum strains, many are not characterized, and it is not known if they retain the functional capacity to form infectious particles that can infect and lysogenize other bacterial hosts. In this study, the genome sequences of 28 V. anguillarum strains revealed 55 different prophage-related elements. Chemical and spontaneous induction allowed a collection of 42 phage isolates, which were classified in seven different groups according to a multiplex PCR assay. One shared prophage sequence, p41 (group III), was present in 17 V. anguillarum strains, suggesting that this specific element is very dynamically exchanged among V. anguillarum populations. Interestingly, the host range of genetically identical phages was highly dependent on the strains used for proliferation, indicating that phenotypic properties of phages were partly regulated by the host. Finally, experimental evidence displayed that the induced phage ɸVa_90-11-287_p41 was able to lysogenize V. anguillarum strain Ba35, and subsequently spontaneously become released from the lysogenized cells, demonstrating an efficient transfer of the phage among V. anguillarum strains. Altogether, the results showed large genetic and functional diversity and broad distribution of prophages in V. anguillarum, and demonstrated the potential of prophages as drivers of evolution in V. anguillarum strains.

scholarly journals Vibrio anguillarum Is Genetically and Phenotypically Unaffected by Long-Term Continuous Exposure to the Antibacterial Compound Tropodithietic Acid

2016 ◽  
Vol 82 (15) ◽  
pp. 4802-4810 ◽  
Author(s):  
Bastian Barker Rasmussen ◽  
Torben Grotkjær ◽  
Paul W. D'Alvise ◽  
Guangliang Yin ◽  
Faxing Zhang ◽  
...  
Keyword(s):  
Food Production ◽  
Fish Larvae ◽  
Vibrio Anguillarum ◽  
Resistant Bacteria ◽  
Continuous Exposure ◽  
Fish Pathogen ◽  
Content Type ◽  
Tropodithietic Acid ◽  
Antibacterial Compound

ABSTRACTMinimizing the use of antibiotics in the food production chain is essential for limiting the development and spread of antibiotic-resistant bacteria. One alternative intervention strategy is the use of probiotic bacteria, and bacteria of the marineRoseobacterclade are capable of antagonizing fish-pathogenic vibrios in fish larvae and live feed cultures for fish larvae. The antibacterial compound tropodithietic acid (TDA), an antiporter that disrupts the proton motive force, is key in the antibacterial activity of several roseobacters. Introducing probiotics on a larger scale requires understanding of any potential side effects of long-term exposure of the pathogen to the probionts or any compounds they produce. Here we exposed the fish pathogenVibrio anguillarumto TDA for several hundred generations in an adaptive evolution experiment. No tolerance or resistance arose during the 90 days of exposure, and whole-genome sequencing of TDA-exposed lineages and clones revealed few mutational changes, compared to lineages grown without TDA. Amino acid-changing mutations were found in two to six different genes per clone; however, no mutations appeared unique to the TDA-exposed lineages or clones. None of the virulence genes ofV. anguillarumwas affected, and infectivity assays using fish cell lines indicated that the TDA-exposed lineages and clones were less invasive than the wild-type strain. Thus, long-term TDA exposure does not appear to result in TDA resistance and the physiology ofV. anguillarumappears unaffected, supporting the application of TDA-producing roseobacters as probiotics in aquaculture.IMPORTANCEIt is important to limit the use of antibiotics in our food production, to reduce the risk of bacteria developing antibiotic resistance. We showed previously that marine bacteria of theRoseobacterclade can prevent or reduce bacterial diseases in fish larvae, acting as probiotics. Roseobacters produce the antimicrobial compound tropodithietic acid (TDA), and we were concerned regarding whether long-term exposure to this compound could induce resistance or affect the disease-causing ability of the fish pathogen. Therefore, we exposed the fish pathogenVibrio anguillarumto increasing TDA concentrations over 3 months. We did not see the development of any resistance to TDA, and subsequent infection assays revealed that none of the TDA-exposed clones had increased virulence toward fish cells. Hence, this study supports the use of roseobacters as a non-risk-based disease control measure in aquaculture.

scholarly journals Quorum Sensing Determines the Choice of Antiphage Defense Strategy in Vibrio anguillarum

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Demeng Tan ◽  
Sine Lo Svenningsen ◽  
Mathias Middelboe
Keyword(s):  
Quorum Sensing ◽  
Cell Density ◽  
Defense Mechanisms ◽  
Vibrio Anguillarum ◽  
Phage Infection ◽  
Phage Resistance ◽  
Fish Pathogen ◽  
Content Type ◽  
Density State ◽  
Infection Pressure

ABSTRACTSelection for phage resistance is a key driver of bacterial diversity and evolution, and phage-host interactions may therefore have strong influence on the genetic and functional dynamics of bacterial communities. In this study, we found that an important, but so far largely overlooked, determinant of the outcome of phage-bacterial encounters in the fish pathogenVibrio anguillarumis bacterial cell-cell communication, known as quorum sensing. Specifically,V. anguillarumPF430-3 cells locked in the low-cell-density state (ΔvanTmutant) express high levels of the phage receptor OmpK, resulting in a high susceptibility to phage KVP40, but achieve protection from infection by enhanced biofilm formation. By contrast, cells locked in the high-cell-density state (ΔvanΟmutant) are almost completely unsusceptible due to quorum-sensing-mediated downregulation of OmpK expression. The phenotypes of the two quorum-sensing mutant strains are accurately reflected in the behavior of wild-typeV. anguillarum, which (i) displays increased OmpK expression in aggregated cells compared to free-living variants in the same culture, (ii) displays a clear inverse correlation betweenompKmRNA levels and the concentration ofN-acylhomoserine lactone quorum-sensing signals in the culture medium, and (iii) survives mainly by one of these two defense mechanisms, rather than by genetic mutation to phage resistance. Taken together, our results demonstrate thatV. anguillarumemploys quorum-sensing information to choose between two complementary antiphage defense strategies. Further, the prevalence of nonmutational defense mechanisms in strain PF430-3 suggests highly flexible adaptations to KVP40 phage infection pressure, possibly allowing the long-term coexistence of phage and host.IMPORTANCEComprehensive knowledge on bacterial antiphage strategies and their regulation is essential for understanding the role of phages as drivers of bacterial evolution and diversity. In an applied context, development of successful phage-based control of bacterial pathogens also requires detailed understanding of the mechanisms of phage protection in pathogenic bacteria. Here, we demonstrate for the first time the presence of quorum-sensing-regulated phage defense mechanisms in the fish pathogenVibrio anguillarumand provide evidence that quorum-sensing regulation allowsV. anguillarumto alternate between different phage protection mechanisms depending on population cell density. Further, our results demonstrate the prevalence of nonmutational defense mechanisms in the investigatedV. anguillarumstrain, which allow flexible adaptations to a dynamic phage infection pressure.

scholarly journals Disruption of Cell-to-Cell Signaling Does Not Abolish the Antagonism of Phaeobacter gallaeciensis toward the Fish Pathogen Vibrio anguillarum in Algal Systems

2013 ◽  
Vol 79 (17) ◽  
pp. 5414-5417 ◽  
Author(s):  
M. J. Prol García ◽  
P. W. D'Alvise ◽  
L. Gram
Keyword(s):  
Quorum Sensing ◽  
Cell Signaling ◽  
Disease Control ◽  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
Wild Type ◽  
Content Type ◽  
Phaeobacter Gallaeciensis ◽  
Algal Cultures

ABSTRACTQuorum sensing (QS) regulatesPhaeobacter gallaeciensisantagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reducedVibrio anguillarumto the same extent as the wild type. Consequently, a combination of probioticPhaeobacterand QS inhibitors is a feasible strategy for aquaculture disease control.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

Gender bias in hospital leadership: a qualitative study on the experiences of women CEOs

2017 ◽  
Vol 31 (2) ◽  
pp. 253-268 ◽  
Author(s):  
Sophie Soklaridis ◽  
Ayelet Kuper ◽  
Cynthia R. Whitehead ◽  
Genevieve Ferguson ◽  
Valerie H. Taylor ◽  
...  
Keyword(s):  
Qualitative Study ◽  
Gender Bias ◽  
Female Leaders ◽  
Content Type ◽  
Hospital Leadership ◽  
Purposeful Sampling ◽  
Women Ceos ◽  
Hospital Ceos ◽  
The Individual ◽  
Systemic Discrimination

Purpose The purpose of this paper is to examine the experiences of gender bias among women hospital CEOs and explore to what these female leaders attribute their success within a male-dominated hospital executive leadership milieu. Design/methodology/approach This qualitative study involved 12 women hospital CEOs from across Ontario, Canada. Purposeful sampling techniques and in-depth qualitative interview methods were used to facilitate discussion around experiences of gender and leadership. Findings Responses fell into two groups: the first group represented the statement “Gender inequality is alive and well”. The second group reflected the statement “Gender inequity is not significant, did not happen to me, and things are better now”. This group contained a sub-group with no consciousness of systemic discrimination and that claimed having no gendered experiences in their leadership journey. The first group described gender issues in various contexts, from the individual to the systemic. The second group was ambivalent about gender as a factor impacting leadership trajectories. Originality/value Representations of women’s leadership have become detached from feminism, with major consequences for women. This study reveals how difficult it is for some women CEOs to identify gender bias. The subtle everyday norms and practices within the workplace make it difficult to name and explain gender bias explicitly and may explain the challenges in understanding how it might affect a woman’s career path.

ChemInform Abstract: Structure of Anguibactin (Ia), a Unique Plasmid-Related Bacterial Siderophore from the Fish Pathogen Vibrio anguillarum

ChemInform ◽  
1989 ◽  
Vol 20 (15) ◽  
Author(s):  
M. A. F. JALAL ◽  
M. B. HOSSAIN ◽  
D. VAN DER HELM ◽  
J. SANDERS-LOEHR ◽  
L. A. ACTIS ◽  
...  
Keyword(s):  
Vibrio Anguillarum ◽  
Fish Pathogen ◽  
Abstract Structure ◽  
Unique Plasmid

The role of organizational culture in the knowledge management process

2015 ◽  
Vol 19 (3) ◽  
pp. 433-455 ◽  
Author(s):  
Christina Ling-hsing Chang ◽  
Tung-Ching Lin
Keyword(s):  
Organizational Culture ◽  
Knowledge Management ◽  
Customer Service ◽  
Survey Methodology ◽  
Cultural Dimensions ◽  
Content Type ◽  
Knowledge Resources ◽  
Positive Effects ◽  
Wide Range ◽  
The Individual

Purpose – The purpose of the study is to focus on the enhancement of knowledge management (KM) performance and the relationship between organizational culture and KM process intention of individuals because of the diversity of organizational cultures (which include results-oriented, tightly controlled, job-oriented, closed system and professional-oriented cultures). Knowledge is a primary resource in organizations. If firms are able to effectively manage their knowledge resources, then a wide range of benefits can be reaped such as improved corporate efficiency, effectiveness, innovation and customer service. Design/methodology/approach – The survey methodology, which has the ability to enhance generalization of results (Dooley, 2001), was used to collect the data utilized in the testing of the research hypotheses. Findings – Results- and job-oriented cultures have positive effects on employee intention in the KM process (creation, storage, transfer and application), whereas a tightly controlled culture has negative effects. Research limitations/implications – However, it would have been better to use a longitudinal study to collect useful long-term data to understand how the KM process would be influenced when organizational culture dimensions are changed through/by management. This is the first limitation of this study. According to Mason and Pauleen (2003), KM culture is a powerful predictor of individual knowledge-sharing behavior, which is not included in this study. Thus, this is the second limitation of this paper. Moreover, national culture could be an important issue in the KM process (Jacks et al., 2012), which is the third limitation of this paper for not comprising it. Practical implications – In researchers’ point of view, results- and job-oriented cultures have positive effects, whereas a tightly controlled culture has a negative effect on the KM process intention of the individual. These findings provide evidences that challenge the perspective of Kayworth and Leidner (2003) on this issue. As for practitioners, management has a direction to modify their organizational culture to improve the performance of KM process. Social implications – Both behavioral and value perspectives of the organizational cultural dimensions (results-oriented, tightly control, job-oriented, sociability, solidarity, need for achievement and democracy) should be examined to ascertain their effects firstly on KM culture and then on the KM process intention of the individual. It is hoped that the current study will spawn future investigations that lead to the development of an integrated model which includes organizational culture, KM culture and the KM process intention of the individual. Originality/value – The results-oriented, loosely controlled and job-oriented cultures will improve the effectiveness of the KM process and will also increase employees’ satisfaction and willingness to stay with the organization.

scholarly journals Inter and intraspecies comparison of the level of selected bacterial phyla in in cattle and sheep based on feces

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Natalia Szeligowska ◽  
Paulina Cholewińska ◽  
Katarzyna Czyż ◽  
Konrad Wojnarowski ◽  
Marzena Janczak
Keyword(s):  
Digestive Tract ◽  
Environmental Conditions ◽  
Genetic Factors ◽  
Disease Symptoms ◽  
Microbiome Composition ◽  
Bacterial Phyla ◽  
As Species ◽  
Individual Host ◽  
Host Effect ◽  
The Individual

Abstract Background The microbiome of the digestive tract of ruminants contains microbial ecosystem that is affected by both environmental and genetic factors. The subject of this study concerns the influence of selected genetic factors, such as species of animals and “host” individual differences on the digestive tract microbiome composition. The results show the core microbiological composition (Firmicutes and Bacteroidetes) of ruminants digestive tract (based on feces) depending on breed and “host”. The Bacteroidetes and Firmicutes phyla are the most abundant in ruminants digestive tract. The aim of the study was to determine the differences prevalence level of Bacteroidetes and Firmicutes phyla in feces of Charolaise cattle and Polish Olkuska Sheep with respect to intra- and inter-species variability. Results The research group in the experiment consisted of animals at the age of 3 months kept in the same environmental conditions – rams of Polish Olkuska Sheep (n = 10) and Charolaise bulls (n = 10). Feces were collected individually from each animal (animals without disease symptoms were selected), living on the same environmental conditions. The analysis of the results in terms of species showed differences in the Firmicutes phylum level and Lactobacillaceae family between rams and bulls. Subsequently, the analysis performed for the “host effect” showed differentiation in the levels of the Bacteroidetes and Firmicutes phyla between individuals in a group and also between the groups. Conclusion The obtained results suggest that, apart from the diet and the environment, the species and the individual host are equally important factors influencing the microbiological composition of the digestive system of ruminants.

Do information technology (IT) capabilities affect hotel competitiveness?

2020 ◽  
Vol 11 (3) ◽  
pp. 447-460
Author(s):  
Nan Hua
Keyword(s):  
Design Methodology ◽  
Financial Data ◽  
Content Type ◽  
It Systems ◽  
Study Results ◽  
It Capabilities ◽  
The Usa ◽  
Lagged Effects ◽  
The Individual ◽  
Direct Measures

Purpose This paper aims to examine the impacts of IT capabilities on hotel competitiveness. Design/methodology/approach This study adapts and extends Hua et al. (2015) and O’Neill et al. (2008) by incorporating the specific measures of IT expenditures as proxies for the relevant IT capabilities to explore the impacts of IT capabilities on hotel competitiveness. Findings This study finds that expenditures on IT Labor, IT Systems and IT Websites exert different impacts on hotel competitiveness. In addition, IT capabilities exert both contemporary and lagged effects on hotel competitiveness. Originality/value This study is the first that uses financial data to capture direct measures of individual IT capabilities and tests the individual impacts of IT capabilities on hotel competitiveness from both contemporaneous and lagged perspectives. It uses a large same store sample of hotels in the USA from 2011 to 2017; as a result, the study results can be reasonably representative of the hotel population in the USA.

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