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This text is an exploration of the ideas and work that I made in 2014

Filamentation of Campylobacter in broth cultures

The transition from rod to filamentous cell morphology has been identified as a response to stressful conditions in many bacterial species and has been ascribed to confer certain survival advantages. Filamentation of Campylobacter jejuni was demonstrated to occur spontaneously on entry in to stationary phase distinguishing it from many other bacteria where a reduction in size is more common. The aim of this study was to investigate the cues that give rise to filamentation of C. jejuni and C. coli and gain insights into the process. Using minimal medium, augmentation of filamentation occurred and it was observed that this morphological change was wide spread amongst C. jejuni strains tested but was not universal in C. coli strains. Filamentation did not appear to be due to release of diffusible molecules, toxic metabolites, or be in response to oxidative stress in the medium. Separated filaments exhibited greater intracellular ATP contents (2.66 to 17.4 fg) than spiral forms (0.99 to 1.7 fg) and showed enhanced survival in water at 4oC and 37oC compared to spiral cells. These observations support the conclusion that the filaments are adapted to survive extra-intestinal environments. Differences in cell morphology and physiology need to be considered in the context of the design of experimental studies and the methods adopted for the isolation of campylobacters from food, clinical and environmental sources

Increase competitive balance in European football: a strategic approach

Over the last two decades, European football has gone through massive structural changes. The end of foreign player quotas (Bosman ruling) and substantial increases in revenue have paved the way toward today’s two-speed Football hierarchy. Top teams’ revenues have increased exponentially while there has been little change in revenues for lower budget clubs. As a result, a trend of competitive imbalance has emerged. UEFA has tried to address these problems with Financial Fair Play (FFP), a regulation system which obliges teams to respect the principle of “break even”, meaning that clubs must not finance themselves with loans and “favors” from wealthy owners. While FFP has been successful in limiting clubs’ indebtedness and ensuring long term viability, it does not have the capacity to deal with competitive imbalance. As long as unequal distributions of revenue persist among teams and leagues, the issue of competitive imbalance will not be solved. This paper focuses on identifying recommendations that could lead to improved competitive balance in football. What would better competitive balance achieve for fans? With player talent more equally distributed, outcomes of matches and league competitions would be more difficult to predict and thus more enjoyable for spectators to follow. In arriving at the recommendations that are presented in this work, measures that have been successfully adopted in other professional sports are examined and tested. Firstly, the distribution of TV revenue in the UEFA Champions League is tackled. By emphasising the importance of one home TV market (market pool), UEFA does not treat all teams equally. Therefore, a system of distribution without market pooling has been developed and proposed. Secondly, the salary cap system was found to be a very effective tool in promoting increased financial equality among clubs and within leagues. Thirdly, the possibility of introducing a playoff system in football was addressed. Playoffs would increase the uncertainty of outcomes until post-season, however, implementation would be complex and would require changes in the number of teams per league. The results of this research reveal that tools to promote competitive balance do indeed exist, however, implementation barriers are quite high. Also, to avoid the threat of top teams deciding to break away and creating their own leagues if the regulating measures are too severe, compromises will be necessary in terms of the strictness of measures that will be adopted and applied

The democratization of luxury and its impact on the image of luxury brands

The market for luxury handbags has considerably changed over the last 20 years. It is our hypothesis here that the market of luxury handbags has gone through a phenomenon of democratization. Focusing on the city of Geneva, the present thesis wants to demonstrate that luxury handbags have become more common in the last 20 years. What are the reasons that led to this phenomenon? What is the point of view of luxury brands in Geneva regarding this evolution? This study is an immersion in the world of luxury handbags. In order to better assess the phenomenon of democratization, two aspects seem important to evaluate. First, is this phenomenon real? Can it be tested and proven empirically? And what is the point of view of consumers on this topic? Second, what is the opinion of the companies producing these luxury handbags? Do they agree that a significant change occurred? Are they responsible for these changes, and what is the impact on luxury brands? This research was conducted according to the design thinking method. The first part of the research is based on a quantitative approach to evaluate the consumer behaviour in the market of luxury handbag. About 220 surveys were distributed in the city of Geneva in order to collect various, and accurate data. The second part of the research is based on a qualitative approach. Three luxury companies were interviewed in order to gain insight into the evolution, and the impact of the democratisation of luxury handbags on the brands. The aim of these interviews was to ask general, open-ended questions in order for the representative of the company to freely speak, and to share with the author the information they were willing to. Once the qualitative data were collected, they have been analysed with the empathy map. This tool allows to have a deeper understanding of a context as it not only takes into consideration the words that the speaker is using but also his attitude. This method of analysing qualitative data grants another dimension to the interview, and gives an idea on how confident the speaker is about his statements. Finally, the recommendations are based on the obtained results. Four recommendations have been suggested for luxury companies in order to maintain the positive aspect of the democratization of luxury, and to moderate the negative aspect of it

Isolation and characterization of Campylobacter bacteriophages from retail poultry

The ability of phages to survive processing is an important aspect of their potential use in the biocontrol of Campylobacter in poultry production. To this end, we have developed a procedure to recover Campylobacter bacteriophages from chilled and frozen retail poultry and have validated the sensitivity of the method by using a characterized Campylobacter phage (i.e., NCTC 12674). By using this method, we have shown that Campylobacter phages can survive on retail chicken under commercial storage conditions. Retail chicken portions purchased in the United Kingdom were screened for the presence of endogenous Campylobacter phages. Thirty-four Campylobacter bacteriophages were isolated from 300 chilled retail chicken portions, but none could be recovered from 150 frozen chicken portions. The phage isolates were characterized according to their lytic profiles, morphology, and genome size. The free-range products were significantly more likely to harbor phages (P < 0.001 by single-factor analysis of variance) than were standard or economy products. This study demonstrates that Campylobacter bacteriophages, along with their hosts, can survive commercial poultry processing procedures and that the phages exhibited a wide range of recovery rates from chicken skin stored at 4°C

Xylan degrading enzymes from fungal sources

Fungi have the ability to degrade xylan as the major component of plant cell wall hemicellulose. Fungi have evolved batteries of xylanolytic enzymes that concertedly act to depolymerise xylan backbones decorated with variable carbohydrate branches. As an alternative to acid extraction in industrial processes the combination of endo-1,4-β-xylanase and β-xylosidase can reduce xylan to xylose. However, unlike chemical extraction procedures enzyme systems can selectively hydrolyse α-L-arabinofuranosyl, 4-O-methyl-α-D-glucuronopyranosyl, acetyl and phenolic branches, and therefore have the potential to deconstruct hemicellulose whilst retaining desirable structural integrity and functionality. The sources, structures and catalytic activities of fungal xylanolytic enzymes are reviewed and discussed in the context of their biotechnological potential

Campylobacter jejuni acquire new host-derived CRISPR spacers when in association with bacteriophages harboring a CRISPR-like Cas4 protein

Campylobacter jejuni is a worldwide cause of human diarrhoeal disease. Clustered Repetitively Interspaced Palindromic Repeats (CRISPRs) and associated proteins allow Bacteria and Archaea to evade bacteriophage and plasmid infection. Type II CRISPR systems are found in association with combinations of genes encoding the CRISPR-associated Cas1, Cas2, Cas4 or Csn2, and Cas9 proteins. C. jejuni possesses a minimal subtype II-C CRISPR system containing cas1, cas2, and cas9 genes whilst cas4 is notably absent. Cas4 proteins possess 5′-3′ exonuclease activity to create recombinogenic-ends for spacer acquisition. Here we report a conserved Cas4-like protein in Campylobacter bacteriophages that creates a novel split arrangement between the bacteriophage and host that represents a new twist in the bacteriophage/host co-evolutionary arms race. The continuous association of bacteriophage and host in the carrier state life cycle of C. jejuni provided an opportunity to study spacer acquisition in this species. Remarkably all the spacer sequences observed were of host origin. We hypothesize that Campylobacter bacteriophages can use Cas4-like protein to activate spacer acquisition to use host DNA as an effective decoy to bacteriophage DNA. Bacteria that acquire self-spacers and escape phage infection must overcome CRISPR-mediated autoimmunity either by loss of the interference functions leaving them susceptible to foreign DNA incursion or tolerate changes in gene regulation

The bacteriophage carrier state of Campylobacter jejuni features changes in host non-coding RNAs and the acquisition of new host-derived CRISPR spacer sequences

Incorporation of self-derived CRISPR DNA protospacers in Campylobacter jejuni PT14 occurs in the presence of bacteriophages encoding a CRISPR-like Cas4 protein. This phenomenon was evident in carrier state infections where both bacteriophages and host are maintained for seemingly indefinite periods as stable populations following serial passage. Carrier state cultures of C. jejuni PT14 have greater aerotolerance in nutrient limited conditions, and may have arisen as an evolutionary response to selective pressures imposed during periods in the extra-intestinal environment. A consequence of this is that bacteriophage and host remain associated and able to survive transition periods where the chances of replicative success are greatly diminished. The majority of the bacteriophage population do not commit to lytic infection, and conversely the bacterial population tolerates low-level bacteriophage replication. We recently examined the effects of Campylobacter bacteriophage/C. jejuni PT14 CRISPR spacer acquisition using deep sequencing strategies of DNA and RNA-Seq to analyze carrier state cultures. This approach identified de novo spacer acquisition in C. jejuni PT14 associated with Class III Campylobacter phages CP8/CP30A but spacer acquisition was oriented toward the capture of host DNA. In the absence of bacteriophage predation the CRISPR spacers in uninfected C. jejuni PT14 cultures remain unchanged. A distinct preference was observed for incorporation of self-derived protospacers into the third spacer position of the C. jejuni PT14 CRISPR array, with the first and second spacers remaining fixed. RNA-Seq also revealed the variation in the synthesis of non-coding RNAs with the potential to bind bacteriophage genes and/or transcript sequences

Campylobacter jejuni acquire new host-derived CRISPR spacers when in association with bacteriophages harboring a CRISPR-like Cas4 protein

Campylobacter jejuni is a worldwide cause of human diarrhoeal disease. Clustered Repetitively Interspaced Palindromic Repeats (CRISPRs) and associated proteins allow Bacteria and Archaea to evade bacteriophage and plasmid infection. Type II CRISPR systems are found in association with combinations of genes encoding the CRISPR-associated Cas1, Cas2, Cas4 or Csn2, and Cas9 proteins. C. jejuni possesses a minimal subtype II-C CRISPR system containing cas1, cas2, and cas9 genes whilst cas4 is notably absent. Cas4 proteins possess 5′-3′ exonuclease activity to create recombinogenic-ends for spacer acquisition. Here we report a conserved Cas4-like protein in Campylobacter bacteriophages that creates a novel split arrangement between the bacteriophage and host that represents a new twist in the bacteriophage/host co-evolutionary arms race. The continuous association of bacteriophage and host in the carrier state life cycle of C. jejuni provided an opportunity to study spacer acquisition in this species. Remarkably all the spacer sequences observed were of host origin. We hypothesize that Campylobacter bacteriophages can use Cas4-like protein to activate spacer acquisition to use host DNA as an effective decoy to bacteriophage DNA. Bacteria that acquire self-spacers and escape phage infection must overcome CRISPR-mediated autoimmunity either by loss of the interference functions leaving them susceptible to foreign DNA incursion or tolerate changes in gene regulation

Complete genome sequence of Salmonella enterica serovar Typhimurium U288

Salmonella enterica serovar Typhimurium U288 has firmly established itself within the United Kingdom pig production industry. The prevalence of this highly pathogenic multidrug-resistant serovar at such a critical point in the food chain is therefore of great concern. To enhance our understanding of this microorganism, whole-genome and plasmid sequencing was performed