Food Science Commons^™

Metagenomic Identification Of A Novel Salt Tolerance Gene From The Human Gut Microbiome Which Encodes A Membrane Protein With Homology To A Brp/Blh-Family Beta-Carotene 15,15'-Monooxygenase, Eamonn P. Culligan, Roy D. Sleator, Julian R. Marchesi, Colin Hill

Department of Biological Sciences Publications

The human gut microbiome consists of at least 3 million non-redundant genes, 150 times that of the core human genome. Herein, we report the identification and characterisation of a novel stress tolerance gene from the human gut metagenome. The locus, assigned brpA, encodes a membrane protein with homology to a brp/blh-family β-carotene monooxygenase. Cloning and heterologous expression of brpA in Escherichia coli confers a significant salt tolerance phenotype. Furthermore, when cultured in the presence of exogenous β-carotene, cell pellets adopt a red/orange pigmentation indicating the incorporation of carotenoids in the cell membrane.

Transcriptome Analysis Of Listeria Monocytogenes Exposed To Biocide Stress Reveals A Multi-System Response Involving Cell Wall Synthesis, Sugar Uptake, And Motility, Aidan Casey, Edward M. Fox, Stephan Schmitz-Esser, Aidan Coffey, Olivia Mcauliffe, Kieran Jordan

Department of Biological Sciences Publications

Listeria monocytogenes is a virulent food-borne pathogen most often associated with the consumption of “ready-to-eat” foods. The organism is a common contaminant of food processing plants where it may persist for extended periods of time. A commonly used approach for the control of Listeria monocytogenes in the processing environment is the application of biocides such as quaternary ammonium compounds. In this study, the transcriptomic response of a persistent strain of L. monocytogenes (strain 6179) on exposure to a sub-lethal concentration of the quaternary ammonium compound benzethonium chloride (BZT) was assessed. Using RNA-Seq, gene expression levels were quantified by sequencing …

Phages Of Non-Diary Lactococci: Isolation And Characterization Of Phi L47, A Phage Infecting The Grass Isolate Lactococcus Lactis Ssp Cremoris Dpc6860, Daniel Cavanagh, Caitríona M. Guinane, Horst Neve, Aidan Coffey, R. Paul Ross, Gerald F. Fitzgerald, Olivia Mcauliffe

Department of Biological Sciences Publications

Lactococci isolated from non-dairy sources have been found to possess enhanced metabolic activity when compared to dairy strains. These capabilities may be harnessed through the use of these strains as starter or adjunct cultures to produce more diverse flavor profiles in cheese and other dairy products. To understand the interactions between these organisms and the phages that infect them, a number of phages were isolated against lactococcal strains of non-dairy origin. One such phage, ΦL47, was isolated from a sewage sample using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. Visualization of phage virions by transmission electron …

Investigation Of Pyrrolizidine Alkaloids In Foods Using Liquid Chromatography Mass Spectrometry, Caroline Griffin

PhDs

Pyrrolizidine Alkaloids (PAs) are known plant toxins which can cause hepatic veno-occlusive disease (HVOD) in both humans and livestock when ingested. Although PAs are primarily known for their hepatotoxicity they also induce genotoxicity, carcinogenicity and pneumotoxicity. PAs are consumed through plants as food, for medicinal purposes, or as contaminants of agricultural crops. Aside from ingesting the plants directly PA exposure may occur through the consumption of honey produced by bees that visit PA-containing plants or by drinking milk produced by animals that have consumed PA-containing plants. Possible PA contamination in our food chain is a potential health risk.

To assess …

Development Of Value Added Products From Spent Kluyveromyces Marxianus Yeast, Rahul Sharma

Theses

Biochemical analysis of spent Kluyveromyces marxianus yeast confirmed the following composition on a dry matter basis: 43.16 % crude protein, 34.56 % total carbohydrate, 7.02 % RNA, and 13.12 % ash content. Carbohydrate components were shown to consist of 20.97 % β-glucan, 9.76 % mannan and 1.21 % chitin while protein characterisation confirmed this yeast’s protein to be a good source of essential amino acids. Total nitrogen, α-amino nitrogen, and descriptive sensory analysis was carried out on yeast extracts derived from yeast autolysis processes carried out at different pH and temperature values. Yeast extract obtained at 50ºC, pH 7.0 was …

A Single Point Mutation In The Listerial Betl Sigma(A)-Dependent Promoter Leads To Improved Osmo- And Chill-Tolerance And A Morphological Shift At Elevated Osmolarity, Ronald F. Hoffman, Susan Mclernon, Audrey Feeney, Colin Hill, Roy D. Sleator

Department of Biological Sciences Publications

Betaine uptake in Listeria monocytogenes is mediated by three independent transport systems, the simplest of which in genetic terms is the secondary transporter BetL. Using a random mutagenesis approach, based on the E. coli XL1 Red mutator strain, we identified a single point mutation in a putative promoter region upstream of the BetL coding region which leads to a significant increase in betL transcript levels under osmo- and chill-stress conditions and a concomitant increase in stress tolerance. Furthermore, the mutation appears to counter the heretofore unreported “twisted” cell morphology observed for L. monocytogenes grown at elevated osmolarities in tryptone soy …

Utilisation Of Spent Dairy Yeast Kluyveromyces Marxianus For The Production Of Flavoured Yeast Extracts., Brendan Mccarra

Theses

Spent dairy yeast Kluyveromyces marxianus (SDYK), a by-product of whey to ethanol fermentations, was investigated as a natural biomass source for the production of alternative flavoured yeast extracts. SDYK which was characterised by a high protein content (55.3% (w/w) ± 0.8) and comparable levels of flavor enhancing amino acids to that of S. cerevisiae was prepared for induced autolysis at different pH values in the presence of inductors sodium chloride and the proteolytic enzyme papain. An induced autolysis process was developed for the production of flavoured yeast extracts in which pH and autolytic treatment applied were found to have a …

Investigation Of Factors Influencing Trichloromethane Levels In Milk And Its Control., Siobhan Ryan

Theses

Trichloromethane (TCM) is an undesirable chemical residue that can develop in milk. While TCM levels in milk are not within ranges of public health concern, it is important that minimal levels are maintained in order to promote the marketing of Irish dairy products abroad. Germany has enacted strict regulations on TCM concentrations in foodstuffs with a recommended level of0.002 mg/kg and re-analyse those milks, subsequent to cause identification and provision of advice on reducing TCM levels in milk. Milk samples were analysed using Gas chromatography (GC) with electron capture detection. The GC method was adapted and a standard curve was …

Evaluation Of Novel Low Molecular Weight Antimicrobial Compounds Produced By Lactic Acid Bacteria., Jiahui Leona Guo

Theses

Fungal food spoilage plays a pivotal role in the deterioration of food and feed systems and some fungi are also able to produce compounds toxic for humans and animals. The mycotoxins produced by fungi can cause serious health hazards and include toxins which are cancerogenic, immunotoxic, teratogenic, neurotoxic, nephrotoxic or hepatotoxic effects and Kashin-Beck disease. In addition to this, fungal spoilage/pathogens cause losses of marketable quality and hygiene of foodstuffs, resulting in major economic problem throughout the world. Nowadays, food spoilage can be prevented using physical and chemical methods, but no efficient strategy has been proposed so far to reduce …

Emerging Dynamics Of Human Campylobacteriosis In Southern Ireland, Susan Bullman, Daniel Corcoran, James O'Leary, Derry O'Hare, Brigid Lucey, Roy D. Sleator

Department of Biological Sciences Publications

Infections with Campylobacter spp. pose a significant health burden worldwide. The significance of Campylobacter jejuni/Campylobacter coli infection is well appreciated but the contribution of non-C. jejuni/C. coli spp. to human gastroenteritis is largely unknown. In this study, we employed a two-tiered molecular study on 7194 patient faecal samples received by the Microbiology Department in Cork University Hospital during 2009. The first step, using EntericBio® (Serosep), a multiplex PCR system, detected Campylobacter to the genus level. The second step, utilizing Campylobacter species-specific PCR identified to the species level. A total of 340 samples were confirmed as Campylobacter genus positive, 329 of …

Probiotic Therapy - Recruiting Old Friends To Fight New Foes, Roy D. Sleator

Department of Biological Sciences Publications

Against a backdrop of increasing antibiotic resistance, and the emergence of new and evolving pathogens, clinicians are increasingly forced to consider alternative therapies - probiotics are one such alternative.

Development Of Pcr Assays To Detect And Characterise Salmonella Isolates From Cheese And Meat Products By Utilizing An Integrated Genomics Approach, Noelle Geraldine Mccarthy

Theses

Salmonella is an extremely important foodborne pathogen which is responsible for millions of cases of gastroenteritis annually. Salmonella outbreaks have been associated with numerous common food stuffs such as meat, dairy and seafood. Traditional culture based methods for the detection Salmonella are labourious and costly. Rapid detection and serovar identification would dramatically decrease the time required to identify Salmonella outbreaks and potential health risks.

In the US 99% of all Salmonella infections are caused by members of Salmonella enterica subspecies 1. Serovars within subspecies 1 can vary due to host specificity and pathogenicity. DNA sequencing projects have provided valuable genomic …

Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey

Physical Sciences Publications

Surveys of DSP (Diarrheic Shellfish Poisoning) toxin profiles in the mussel Mytilus galloprovincialis from coastal waters of the central Adriatic Sea, over the years 1995 to 2001, demonstrate that incidents of shellfish toxicity in this area are dominated by the occurrence of okadaic acid (OA) and a PTX derivative, 7-epi-pectenotoxin-2-seco acid (7-epi-PTX-2SA). Toxin composition and the relative ratio of toxic components in shellfish is in correlation with the occurrence of DSP producing organisms from the Dinophysis species along with Prorocentrum micans and Lingulodinium polyedrum. The occurrence of D. sacculus shortly before the appearance of OA in shellfish implicates its possible …

System Identification Of A Pasteurisation Process: A Comparison Of Direct And Indirect Methods, Niel Canty

Theses

The primary focus of this research is to identify a linear model for a direct steam injection (DSI) pasteurisation process which is a component of a large-scale pilot evaporation process widely used in the dairy industry. The pasteurisation process has been identified as a key component of the evaporation process. The author believes that no previously published work has focused on identifying models for a DSI pasteurisation process which makes this work an original contribution to the area. The pasteurisation process can be modelled as a single-input, single-output (SISO) process with a measurable disturbance. Thus two transfer functions were required …

The Development Of Functional Food Ingredients From Yeast Cell Wall Beta Glucans, Susan Keogh

Theses

The intracellular contents of spent yeast can be used to produce flavours and flavour enhancers. However there still remains after this process, a significant quantity of cell wall material, which makes up 20-25% of the dry weight of yeast biomass. A major component of the yeast cell wall is the polysaccharide P-glucan. This project involved the investigation of the extraction and characterisation of p-glucan as well as its evaluation as a functional food ingredient. A preparation of spent yeast p-glucan was obtained from two types of spent yeast species, Saccharomyces cervisiae (brewers yeast) and Kluyveromyces marxianus (dairy yeast) obtained from …

Integronlike Structures In Campylobacter Spp. Of Human And Animal Origin, Brigid Lucey, D. Crowley, P. Moloney, B. Cryan, M. Daly, F. O'Halloran, E. J. Threlfall, S. Fanning

Department of Biological Sciences Publications

Resistance to antimicrobial agents used to treat severe Campylobacter spp. gastroenteritis is increasing worldwide. We assessed the antimicrobial resistance patterns of Campylobacter spp. isolates of human and animal origin. More than half (n = 32) were resistant to sulphonamide, a feature known to be associated with the presence of integrons. Analysis of these integrons will further our understanding of Campylobacter spp. epidemiology.