Description:
The aim of this study was to investigate the factors affecting the survival and growth of four food-borne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in sweet and fermenting brewery wort. The Gram-negative pathogens (E. coli and Salm. Typhimurium) were capable of growth during the initial stages of fermentation in hopped wort, although they were quickly inactivated when added during the later stages of fermentation. When the wort was left unpitched, the two Gram-negative pathogens grew unabated. Pathogen growth and survival was enhanced as the pH was increased, and as both the ethanol and original gravity were decreased. Although having no effect on the Gram-negative pathogens, low levels of hop iso-
Description:
Many viruses have as part of their arsenal the ability to modulate the apoptotic pathways of the host. It is counter-intuitive that such simple organisms would be efficient at regulating this the most crucial pathway within the host, given the relative complexity of the host cells. Yet, viruses have the potential to initiate or stay the onset of programmed cell death through the manipulation of a variety of key apoptotic proteins. It is the intention of this review to provide an overview of viral gene products that are able to promote or inhibit apoptotic death of the host cell and to discuss their mechanisms of action. It is not until recently that the depth at which viruses exploit the apoptotic pathways of their host has been seen. This understanding may provide a great opportunity for future therapeutic ventures.
Description:
Bone marrow stromal cells (BMSC) from cats experimentally infected with feline immunodeficiency virus (FIV) were shown to contain FIV provirus using polymerase chain reaction and viral products were detected in culture supernatant using reverse transcriptase and enzyme linked immunosorbent assay techniques. Peripheral blood mononuclear cells from FIV-free cats co-cultured with infected bone marrow cells became productively infected with FIV. Such evidence supports the hypothesis that BMSC are a reservoir for FIV. Furthermore, BMSC produced virions capable of infecting susceptible cells and may represent an important source of infectious virus to cells of the macrophage lineage and/or hemopoietic progenitor cells, both of which ultimately become widely disseminated throughout the body.
Description:
The current state of myiasis vaccine technologies are reviewed mainly in the primary research genera of Lucilia and Hypoderma. The importance of myiasis flies as primary causes of morbidity and mortality in agricultural species and man has not diminished despite the existence of good control strategies. However, the development of vaccines against myiasis infections has been relatively quiescent for more than 10 years despite the rapid development of genomic and proteomic analysis and of skills in data interpretation. The value of vaccine research in an era of chemical primacy is analysed. In fact, recent findings of drug resistance and the impact of animal welfare concerns should mean a renewed interest in alternative controls. The reasons that this has not been true to date are explored and new possibilities discussed.
Description:
The current state of myiasis vaccine technologies are reviewed mainly in the primary research genera of Lucilia and Hypoderma. The importance of myiasis flies as primary causes of morbidity and mortality in agricultural species and man has not diminished despite the existence of good control strategies. However, the development of vaccines against myiasis infections has been relatively quiescent for more than 10 years despite the rapid development of genomic and proteomic analysis and of skills in data interpretation. The value of vaccine research in an era of chemical primacy is analysed. In fact, recent findings of drug resistance and the impact of animal welfare concerns should mean a renewed interest in alternative controls. The reasons that this has not been true to date are explored and new possibilities discussed.
Description:
Infections with gastrointestinal nematode parasites are a major problem for the sheep industry in Australia and New Zealand and have been the subject of intensive research to define mechanisms of resistance. The ability to take continuous biopsy samples of infected organs and cannulate both afferent and efferent lymphatics of draining lymph nodes has been particularly useful in illuminating the kinetics of immune responses at the site of infection. Distinct localized immune responses were shown to occur within and between sheep breeds at different sensitization regimes, as well as at different developmental stages of the parasite within the host. Using localized antibodies derived from mucus and lymph nodes, two major antigens have been identified on the infective L3 stage, which may be responsible for inducing protection and have potential as vaccine targets. Recent advances in sheep genomics also offer the potential of gaining further insight into the underlying genetics of resistance to nematode infections.
Description:
We evaluated loop-mediated isothermal amplification end-point detection methods for Salmonella, Shigella, and Vibrio cholerae. Detection sensitivities were comparable to real-time PCR methods. The colorimetric dyes hydroxynaphthol blue and SYBR Green I showed increased sensitivity when compared to visual and automated turbidity readings. End-point colorimetric dyes promise great utility in developing settings.
Description:
Liver flukes produce cathepsin B and cathepsin L in their excretory–secretory material. These proteases are proposed to be key virulence factors for parasite infection, and are therefore targets for vaccination. Cathepsin B is predominately released in the juvenile stage of the life cycle, while different cathepsin L's are released throughout the cycle. Three proteases (cathepsin L5, cathepsin L1g and cathepsin B) were expressed in yeast from cDNA clones isolated from adult, metacercariae and newly excysted juvenile flukes respectively. Each was used singly or in combination to vaccinate rats that were subsequently challenged with Fasciola hepatica metercercariae. Each protein induced an immune response, and all groups vaccinated with recombinant protein yielded significantly fewer and smaller flukes than the control group. Maximal protection of 83% was seen in the group vaccinated with cathepsin B and cathepsin L5 in combination.
Description:
Sheep, goats and cattle represent the most numerous and economically important agricultural species worldwide used as sources for milk, fibre and red meat. In addition, in the developing world, these species often represent the sole asset base for small-holder livestock farmers and cattle/buffaloes often provide the majority of draught power for crop production. Production losses caused by helminth diseases of these animals are a major factor in extending the cycle of poverty in developing countries and a major food security issue for developed economies. Fasciola spp. are one of the most important zoonotic diseases with a global economic impact in livestock production systems and a poorly defined but direct effect on human health. Improvements in human and animal health will require a concerted research effort into the development of new accurate and simple diagnostic tests and increased vaccine and drug development against Fasciola infections. Here, the use of definitive natural host breeds with contrasting resistance to Fasciola infections is discussed as a resource to contrast parasite–host interactions and identify parasite immune evasion strategies. Such studies are likely to boost the discovery of new vaccine, drug and diagnostic candidates and provide the foundation for future genetic selection of resistant animals.
Description:
In the current study, three independent trials directly compared Fasciola gigantica and Fasciola hepatica infection of ITT sheep. In all trials, F. hepatica infection resulted in higher worm burden recoveries and greater physiological damage to ITT sheep. Developmental differences of the two Fasciola species were also observed during the first twelve weeks of a primary infection, where the migration and growth of F. hepatica was more rapid than F. gigantica. Various immunological blood parameters were measured and indicated similar kinetics in the humoral and cellular responses during the time course of infection with each Fasciola species. In contrast to F. hepatica infection, we demonstrate an innate and adaptive comparative ability of ITT sheep to resist the early stages of infection with F. gigantica infection. Unraveling the mechanisms leading to this differential resistance may potentially lead to new methods for the control of fasciolosis and other human liver flukes.
Description:
The last 50. years of research into infections in Australia and New Zealand caused by larvae of the sheep blowfly, Lucilia cuprina, have significantly advanced our understanding of this blowfly and its primary host, the sheep. However, apart from some highly effective drugs it could be argued that no new control methodologies have resulted. This review addresses the major areas of sheep blowfly research over this period describing the significant outcomes and analyses, and what is still required to produce new commercial control technologies. The use of drugs against this fly species has been very successful but resistance has developed to almost all current compounds. Integrated pest management is becoming basic to control, especially in the absence of mulesing, and has clearly benefited from computer-aided technologies. Biological control has more challenges but natural and perhaps transformed biopesticides offer possibilities for the future. Experimental vaccines have been developed but require further analysis of antigens and formulations to boost protection. Genetic technologies may provide potential for long-term control through more rapid indirect selection of sheep less prone to flystrike. Finally in the future, genetic analysis of the fly may allow suppression and perhaps eradication of blowfly populations or identification of new and more viable targets for drug and vaccine intervention. Clearly all these areas of research offer potential new controls but commercial development is perhaps inhibited by the success of current chemical insecticides and certainly requires a significant additional injection of resources.
Description:
Objectives The efflux inhibitor 1-(1-naphthylmethyl)-piperazine (NMP) has been demonstrated to reverse multidrug resistance in Acinetobacter baumannii. We investigated the interaction of NMP with tigecycline and three other tetracyclines on clinical isolates of A. baumannii. Methods One hundred and four clinical isolates of Acinetobacter were tested for susceptibility to tigecycline, minocycline, doxycycline and tetracycline by disc diffusion, and tigecycline MICs were determined by Etest, both in the presence and absence of NMP. Tigecycline MICs and zones of inhibition were interpreted using the BSAC guidelines. An OXA carbapenemase multiplex PCR was also performed on each isolate. Results Mean zones of inhibition for tetracycline, doxycycline and minocycline increased by 11.3%, 22.9% and 11.2%, respectively, in the presence of NMP. In contrast, tigecycline susceptibility was decreased in the presence of NMP, with mean zones of inhibition decreasing by 8.4%. Based on PCR results, all but six isolates belonged to the OXA-23 clone 1. Conclusions Susceptibility to tigecycline of the A. baumannii OXA-23 clone 1 prevalent in the UK is reduced (∼2-fold) by the presence of the efflux inhibitor NMP. NMP does not have the same effect on susceptibility to other tetracyclines.
Description:
Gastrointestinal nematode parasites undergo several developmental stages within their mammalian host, each presenting different antigenic challenges to the immune system. To examine the expression of different immune mediators over time, biopsy samples were collected from the cannulated abomasum (true stomach) of immune sheep at several times after a challenge infection with Haemonchus contortus L3s. IL-5 and IL-13 mRNA expression levels were significantly increased above saline-challenged control levels at 5 and 7 days post challenge, while IL-4 showed an earlier peak at day 2 post challenge. IL-5, IL-13 and IL-4, as well as IFN-
Description:
Rapid rejection or immune exclusion of challenge larvae is a well recognised phenomenon in sheep hypersensitised by repeated infection with gastrointestinal nematodes. While mast cells and globule leukocytes (GLs) are typically associated with this rapid rejection response, the exact mechanisms and mediators involved are not known. This study has adapted a recently developed ex vivo tissue explant model to examine in more detail the cells and mediators involved in preventing establishment of Haemonchus contortus L3s in abomasal tissue of sensitised sheep. Hypersensitisation of sheep by repeated larval infection resulted in a significant inhibition of larval establishment in abomasal tissue cultures and the extent of inhibition was dependent on the sensitisation dose. Both mast cells and GLs, but not eosinophils, were increased in abomasal tissues of hypersensitised sheep. Globule leucocyte numbers decreased significantly after 3 h of culture, independent of the addition of L3s. In contrast, mast cell numbers only decreased after addition of L3s to the tissue cultures and this was associated with an increased release of histamine in tissue washes after incubation with L3s. Although, there was no significant difference in the number of tissue eosinophils between the groups, there was a marked increase in the eosinophil-specific protein, galectin-14, in tissue washes of the hypersensitised sheep after culture, suggesting eosinophils and their products may play a hitherto unrecognised role in the rapid rejection response. Further studies using specific inhibitors in this ex vivo tissue explant model may delineate the relative role of each cell population and mediator in the rapid rejection process.
Description:
Gaining hands-on experience throughout an under graduate degree is regarded as a competitive advantage by science students. At the Gippsland campus of Monash University, the Industry Placement Program (IPP) allows students to gain industry experience throughout their entire course. Science students enrolled in the IPP undertake a practicum learning experience, equivalent to a 12-point unit, whose emphasis is on identifying and building transferable skills while gaining technical competency. The combination of academic studies, relevant paid work experience and professional development training produces capable, work-ready graduates
Description:
This study compares the susceptibility to Haemonchus contortus infection in two breeds of sheep endemic to the Canary Islands, the Canaria Hair Breed sheep and the Canaria sheep. Sheep were experimentally infected with 20,000 larvae of H. contortus and animals killed on days 7 and 28 post-infection. No difference between sheep breeds were detected in immature worm counts at days 7 or 28 post-infection. However, in comparison to the Canaria sheep breed, the Canaria Hair Breed sheep showed lower mean faecal egg counts, lower adult worm counts, lower number of eggs in utero and female worm stunting. Overall, these data suggest that the Canaria Hair Breed sheep has a greater resistance to H. contortus infection than Canaria sheep, and that this resistance may act at the level of the adult parasite.
Description:
Indonesian thin-tail (ITT) sheep can resist infection with Fasciola gigantica but not F. hepatica and presents an ideal model to investigate the mechanisms of liver fluke resistance in a natural host. This study examines the local and systemic immune responses of sheep during Fasciola infection and demonstrates that different anatomical tissues display distinct cytokine profiles consistent with liver fluke migration. The study also reveals a significant difference in the cytokine and antibody profiles of ITT sheep infected with F. gigantica compared with F. hepatica, with a higher ratio of IL-4/IFN-
Streptococcus pneumoniae and Haemophilus influenzae in paediatric meningitis patients at Goroka General Hospital, Papua New Guinea : Serotype distribution and antimicrobial susceptibility in the pre-vaccine era