Enterococci in Food Fermentations: Functional and Safety Aspects

End of Project ReportTeagasc acknowledges with gratitude financial assistance from the EU Framework Programme. This project was part of a larger EU funded Shared Cost project (FAIR-CT97-3078)Enterococci are natural residents of the human and animal gastrointestinal tracts; many species are also found in soil, plants and food. These organisms also form an important part of the microflora of many cheeses, especially those made in Southern Europe, where they can reach levels of 107 - 108 cfu/g. There is contradictory information on their role in flavour development in cheese with some studies showing that they have a positive effect and others a negative one. Enterococcus faecalis, Ec. faecium and Ec. durans are the important species found in cheese, though recent results from our laboratory show that Ec. casseliflavus may also be important (see below). Many of these species withstand pasteurisation. Their presence in food has been questioned because they are responsible for many nosocomial infections in hospitals. They are also promiscuous and easily transfer antibiotic resistance to other organisms and acquire resistance to vancomycin themselves. Cheddar cheese has a complex microflora and is conducive to growth of many bacteria, especially lactic acid bacteria. Enterococci are facultative anaerobes, which ferment lactose and can grow in high salt concentrations. Therefore, they should grow in cheese if they are present in the raw milk. Phenotypically they can be confused with starter lactococci. Traditionally, they are separated from lactococci by their ability to grow at 45°C and in 6.5% salt. However, these tests have serious drawbacks since some species of enterococci cannot grow at 45°C and some lactococci can grow at 45°C and in 6.5% salt. The effect of enterococci on flavour development in Cheddar cheese has not been studied to any great extent. The overall objectives of this collaborative project were to investigate the taxonomic relationships between food, veterinary and clinical isolates of enterococci, their virulence, their ability to produce toxins, their antibiotic resistance and their technological performance in cheesemaking. The specific objectives of the Moorepark team were to study the co-metabolism of citrate and sugar by enterococci, develop a DNA probe to distinguish between Enterococcus and Lactococcus and evaluate the contribution of enterococci to flavour development in Cheddar cheese.European Unio

A previously unknown disease of farmed atlantic salmon: pathology and establishment of bacterial aetiology

A previously unknown disease of Atlantic salmon Salmo salar occurred on a seawater farm in Ireland, during 1992 and 1993. The gross pathology and the histopathology of the disease are described. A distinctive histological feature of the disease was the presence of intracellular Gram-negative bacteria in several tissues. In particular, the endothelial cells of the kidney glomeruli were enlarged and contained densely packed bacteria within cytoplasmic vacuoles. During later stages of the disease, most tissues showed numerous areas of necrosis surrounded by lymphoid cells. A bacterium was isolated on axenic media, and was demonstrated to be the causative agent by laboratory infectivity trials. The bacterium was approximately 0.4 x 0.6 mum in size in vivo, but also showed filamentous forms (<5 mum) in vitro. In culture it was a slow-growing facultative or aerotolerant anaerobe, requiring serum or blood for growth. It was not possible to characterize the organism by standard biochemical reactions, but additional characterization tests are in progress

A previously unknown disease of farmed atlantic salmon: pathology and establishment of bacterial aetiology

A previously unknown disease of Atlantic salmon Salmo salar occurred on a seawater farm in Ireland, during 1992 and 1993. The gross pathology and the histopathology of the disease are described. A distinctive histological feature of the disease was the presence of intracellular Gram-negative bacteria in several tissues. In particular, the endothelial cells of the kidney glomeruli were enlarged and contained densely packed bacteria within cytoplasmic vacuoles. During later stages of the disease, most tissues showed numerous areas of necrosis surrounded by lymphoid cells. A bacterium was isolated on axenic media, and was demonstrated to be the causative agent by laboratory infectivity trials. The bacterium was approximately 0.4 x 0.6 mum in size in vivo, but also showed filamentous forms (<5 mum) in vitro. In culture it was a slow-growing facultative or aerotolerant anaerobe, requiring serum or blood for growth. It was not possible to characterize the organism by standard biochemical reactions, but additional characterization tests are in progress

Cultural values, plagiarism, and fairness: when plagiarism gets in the way of learning

The dramatic increase in the number of overseas students studying in the United Kingdom and other Western countries has required academics to reevaluate many aspects of their own, and their institutions', practices. This article considers differing cultural values among overseas students toward plagiarism and the implications this may have for postgraduate education in a Western context. Based on focus-group interviews, questionnaires, and informal discussions, we report the views of plagiarism among students in 2 postgraduate management programs, both of which had a high constituency of overseas students. We show that plagiarist practices are often the outcome of many complex and culturally situated influences. We suggest that educators need to appreciate these differing cultural assumptions if they are to act in an ethical manner when responding to issues of plagiarism among international students

Data from: Population structure, genetic connectivity, and adaptation in the Olympia oyster (Ostrea lurida) along the west coast of North America

Effective management of threatened and exploited species requires an understanding of both the genetic connectivity among populations and local adaptation. The Olympia oyster (Ostrea lurida), patchily distributed from Baja California to the central coast of Canada, has a long history of population declines due to anthropogenic stressors. For such coastal marine species, population structure could follow a continuous isolation-by-distance model, contain regional blocks of genetic similarity separated by barriers to gene flow, or be consistent with a null model of no population structure. To distinguish between these hypotheses in O. lurida, 13,424 single-nucleotide polymorphisms (SNPs) were used to characterize rangewide population structure, genetic connectivity, and adaptive divergence. Samples were collected across the species range on the west coast of North America, from southern California to Vancouver Island. A conservative approach for detecting putative loci under selection identified 235 SNPs across 129 GBS loci, which were functionally annotated and analyzed separately from the remaining neutral loci. While strong population structure was observed on a regional scale in both neutral and outlier markers, neutral markers had greater power to detect fine-scale structure. Geographic regions of reduced gene flow aligned with known marine biogeographic barriers, such as Cape Mendocino, Monterey Bay, and the currents around Cape Flattery. The outlier loci identified as under putative selection included genes involved in developmental regulation, sensory information processing, energy metabolism, immune response, and muscle contraction. These loci are excellent candidates for future research and may provide targets for genetic monitoring programs. Beyond specific applications for restoration and management of the Olympia oyster, this study lends to the growing body of evidence for both population structure and adaptive differentiation across a range of marine species exhibiting the potential for panmixia. Computational notebooks are available to facilitate reproducibility and future open-sourced research on the population structure of Ostrea lurida