The Ability of Hop Extracts to Reduce the Methane Production of Methanobrevibacter ruminantium.

BACKGROUND: Methane emissions from agriculture are responsible for over 40% of the world's greenhouse gas emissions. In the past, antibiotics were used to control methane production by animals, but concerns over the emergence and spread of antibiotic-resistant bacteria to humans have prompted a search for alternative approaches. Hops are the flowers of the hop plant Humulus lupulus. They have been used to feed cattle for many years and are known to contain antibacterial compounds, and their extracts have been shown to kill members of the Mycobacterium spp including Mycobacterium bovis, the causative agent of bovine tuberculosis as well as a number of human pathogens. In this study, hop extracts were studied for their ability to inhibit methane production from Methanobrevibacter ruminantium, a major methane-producing archaeon found in the rumen of cattle. METHODS: Methanobrevibacter ruminantium M1T (DSM 1093) was grown at 37°C for 30 days, and the amount of methane produced at different time points during this period was measured using gas chromatography. The archaeon was exposed to commercial hop extracts (tetra-hydro-iso-alpha acid and beta acid) and to aqueous hop extracts of a range of hop variants, and their effect on methane production was determined. RESULTS: All of the extracts reduced the level of methane production of M. ruminantium over the 30-day period compared to the negative control (sterile distilled water). The commercial hop extracts were the most effective at inhibiting methane production over the course of the experiment in contrast to the aqueous extracts, which showed a gradual reduction of inhibition with time. CONCLUSIONS: Hops contain compounds which inhibit methane production. Given that hops can be safely fed to cattle, this raises the possibility of rationally designing a feed strategy which could reduce greenhouse gas emissions and protect against bovine tuberculosis. This study recommends that further research be undertaken to further identifying bioactive components from hops and their efficacy against a range of archaea.

The effect of hospital biocide sodium dichloroisocyanurate on the viability and properties of Clostridium difficile spores.

Clostridium difficile is the primary cause of healthcare-associated diarrhoea globally and produces spores which are resistant to commonly used biocides and are able persist on contaminated surfaces for months. This study examined the effect of sublethal concentrations of the biocide sodium dichloroisocyanurate (NaDCC) on the viability of spores produced by 21 clinical isolates of C. difficile representing a range of PCR ribotypes. Spores exposed to 500 ppm NaDCC for 10 min exhibited between a 4-6 log10 reduction in viability which was independent of spore PCR ribotype. The effect of sublethal concentrations of biocide on the surface properties of exosporium positive and negative clinical isolates was determined using a spore adhesion to hydrocarbon (SATH) assay. These isolates differed markedly in their responses suggesting that exposure to biocide can have a profound effect on hydrophobicity and thus the ability of spores to adhere to surfaces. This raises the intriguing possibility that sublethal exposure to NaDCC could inadvertently promote the spread of the pathogen in healthcare facilities. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to report on changes in Clostridium difficile spore surface property after exposure to sublethal levels of the commonly used biocide sodium dichloroisocyanurate. The implications of these changes to the spore surface include increased adherence of the spores to inorganic surfaces which can directly contribute to persistence and spread of spores within the hospital environment.

The role of the exosporium in the environmental distribution of anthrax.

AIMS: To determine the contribution of the exosporium, the outer layer of the Bacillus anthracis spore, to soil attachment. Persistence of spores in soil and their ability to infect animals has been linked to a range of factors which include the presence of organic material and calcium (OMC), pH > 6.0, temperatures above 15.5°C and cycles of local flooding which are thought to transport buried spores to the surface. METHODS AND RESULTS: The ability of wild type (exosporium +ve) and sonicated (exosporium -ve) spores to bind to soils which differed in their composition was determined using a flow-through soil column-based method. A statistically significant difference (P < 0.05) in the binding of wild type spores was observed with spores adhering more firmly to the soil with the highest OMC content. We also found that the removal of the exosporium increased the ability of the spore to adhere to both soil types. CONCLUSION: Structures within the exosporium affected the ability of B. anthracis spores to bind to different soil types. Not surprisingly, wild type spores adhered to soil which has been shown to favour the persistence of the pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY: The ability to persist in and colonise the soil surface is a key requirement of a pathogen which infects grazing animals. By characterising the process involved, we will be better placed to develop strategies to disrupt the infection cycle.

Exploring the relationship between social identity and workplace jurisdiction for new nursing roles: a case study approach.

BACKGROUND: The introduction of new healthcare roles internationally has had mixed results with some evidence that variations can be accounted for by the manner of their introduction rather than role content. Explanation may be found partly in the ways in which new roles establish a workplace jurisdiction; that is, recognition in the workplace of a role's legitimate rights to undertake a particular scope of practice. OBJECTIVE: To explore the factors that influence the development of workplace jurisdiction of new nursing roles. DESIGN AND SETTING: Critical realist multiple case study design within two NHS Acute Hospital Trusts in England and two new nursing roles as embedded units of analysis in each case (n=4 roles). In Phase 1, data were collected through semi-structured interviews (n=21), non-participant observation of committees (n=11), partial participant observation and shadowing of the role holders' working day (n=9), together with analysis of organisational documents (n=33). In Phase 2, follow up interviews with role-holders (n=4) were conducted. Participants Staff in new nursing roles (n=4) were selected purposively as embedded units according to the theoretical framework and other informants (n=17) were selected according to the study propositions. RESULTS: Qualitative analysis demonstrated that different role drivers produced two different role types, each of whom faced different challenges in negotiating the implementation of the role in the workplace. Negotiation of workplace jurisdiction was shown to be dependent on sharing social identities with co-workers. Four major workplace identities were found: professional, speciality, organisational and relational. CONCLUSION: The current focus on setting legal and public jurisdictions for new nursing roles through national standards and statutory registration needs to be complemented by a better understanding of how workplace jurisdiction is achieved. This study suggests that social identity is a significant determinant.

Strategies for assessing the degree of photodamage to skin: a systematic review of the literature.

As our understanding of the role of ultraviolet (UV) radiation exposure in causing skin cancer continues to be enhanced, it is important that clinicians and researchers are familiar with the various methods for assessing photodamage to skin. This paper provides a systematic review of the published literature on invasive and noninvasive methods used to quantify lifetime UV exposure ('photoageing'). Clinical examination, histopathology, immunohistochemistry, skin surface topography and ultrasound, in addition to newer technologies such as reflectance confocal microscopy, optical coherence tomography and multiphoton tomography, are reviewed. It is concluded that histopathological solar elastosis alone should not be viewed as a 'gold standard' diagnostic test and that there is no single method available to give accurate quantification of the degenerative changes associated with photodamage. Although additional research into sensitivity and specificity is still needed, skin surface topography currently has the most support in the literature as a valid and reliable noninvasive tool for the assessment of photoageing.

The pit and the pendulum: the impact on teen smokers of including a designated smoking area in school tobacco control policy.

Thirty per cent of school districts in British Columbia do not ban smoking outright on school grounds, and in several instances, smoking is permitted in smoking pits, regardless of school district policy. While there is evidence to suggest that enforcing a tobacco-free environment for students does reduce adolescent smoking rates, the concomitant safety and discipline problems it creates for school staff and administration are demanding and complex, and may override concerns regarding student smoking. This study uses a qualitative approach to explore the meanings that students place on tobacco control policy and the impact that these meanings have on their own smoking behaviours. We found that students were surprised and concerned that smoking was permitted on school property and that it negatively impacted their own tobacco prevention/control/cessation attempts.

Past, imminent and future human medical countermeasures for anthrax.

AIM: Anthrax is caused by the bacterium Bacillus anthracis. Although primarily a disease of animals, it can also infect man, sometimes with fatal consequences. As a result of concerns over the illicit use of this organism, considerable effort is focussed on the development of therapies capable of conferring protection against anthrax. This brief review will describe the efforts being made to address these issues. METHODS AND RESULTS: A review of the literature and the proceedings of the sixth international conference on anthrax, held in Santa Fe, USA in 2005 shows intense activity, but there has been as yet no real progress. While effective antibiotics, antitoxins and vaccines are available, concerns over their toxicity and the emergence of resistant strains have driven the development of second-generation products. The principal target for vaccine development is Protective Antigen (PA), the nontoxic cell-binding component of anthrax lethal toxin. While the recombinant products currently undergoing human clinical trials will offer considerable advantages in terms of reduced side effects and ease of production, they would still require multiple, needle-based dosing, and the inclusion of the adjuvant alum makes them expensive to administer and stockpile. To address these issues, researchers are developing vaccine formulations, which stimulate rapid protection following needle-free injection (nasal, oral or transcutaneous), and are stable at room temperature to facilitate stockpiling and mass vaccination programs. CONCLUSIONS: An array of medical countermeasures targeting B. anthracis will become available over the next 5-10 years. SIGNIFICANCE AND IMPACT OF THE STUDY: The huge investment of research dollars is expected to dramatically expand the knowledge base. A better understanding of basic issues, such as survival in nature and pathogenesis in humans, will facilitate the development of new modalities to eliminate the threat posed by this organism.

Bacillus anthracis, a story of nature subverted by man.

Bacillus anthracis is a pathogen of animals which rarely infects humans. Its use as a bioweapon has stimulated efforts to develop genetic typing methods and therapeutics to respond to an attack. Of particular concern is the transfer of virulence genes from B. anthracis to other closely related strains of bacillus.

Co-immunisation with a plasmid DNA cocktail primes mice against anthrax and plague.

The protective antigen (PA) of Bacillus anthracis and the V antigen of Yersinia pestis are potent immunogens and candidate vaccine sub-units. When plasmid DNA encoding either PA or V antigen was used to immunise the Balb/c mouse, a low serum IgG titre was detected (log (10)1.0 or less) which was slightly increased by boosting with plasmid DNA. However, when mice immunised with plasmid DNA were later boosted with the respective recombinant protein, a significant increase in titre (up to 100-fold) was observed. Mice primed with a combination of each plasmid and boosted with a combination of the recombinant proteins, were fully protected (6/6) against challenge with Y. pestis. This compared favourably with mice primed only with plasmid DNA encoding the V antigen and boosted with rV, which were partially protected (3/6) against homologous challenge or with mice primed and boosted with plasmid DNA encoding the V antigen which were poorly protected (1/6). Combined immunisation with the two plasmid DNA constructs followed by boosting with a combination of the encoded recombinant proteins enhanced the protective immune response to Y. pestis compared with priming only with plasmid DNA encoding the V antigen and boosting with rV. This enhancement may be due to the effect of CpG motifs known to be present in the plasmid DNA construct encoding PA.

Bacillus anthracis, a bug with attitude!

The sequencing of the Bacillus anthracis genome and virulence plasmids represents the greatest advance in anthrax research in the past 100 years. The data will provide the foundation of all future work on this organism and will be invaluable to researchers in their battle to understand the basis of the host-microbe interaction.

Biodegradable microparticles with different release profiles: effect on the immune response after a single administration via intranasal and intramuscular routes.

In the development of single-dose microparticulate vaccines, identification of the type of protein release profile required to elicit high and sustainable immune responses is important. Microparticles exhibiting different protein release profiles (continuous, pulsatile and plateau) were made by solvent evaporation or solvent extraction methods from biodegradable polymers encapsulating the model antigen, bovine serum albumin (BSA). The immune responses obtained after a single intranasal or intramuscular administration of microparticles were determined, and also after a subcutaneous boost after 11 months. Microparticles were manufactured with acceptable protein loading and average volume size ranging from 1 to 10 microm. The integrity of BSA extracted and released from microparticles after 2 months incubation was retained. Microparticulate preparations administered by either intranasal or intramuscular routes, evoked rapid, high titre and long-lived (up to 11 months after priming) specific serum IgG responses which were significantly greater than for free BSA. The type of protein release from microparticles had no significant effect on the systemic immune responses. Interestingly, a formulation exhibiting a plateau-release profile was the only microparticulate system capable of inducing significantly greater IgA responses than free BSA after intranasal immunization. This study shows the benefit of microencapsulation in inducing high and long-lasting systemic immune responses after a single dose by both parenteral and mucosal delivery. We conclude that of the microparticles tested, the longevity and magnitude of humoral responses was not effected by the type of in-vitro protein release profile.

Using communicative action in the primary prevention of cancer.

The primary prevention of disease, including cancer, has been a major part of health promotion and health education for decades. However, the long-term results of these strategies have been mixed, and primary prevention as an instrument of cancer control continues to fail to live up to either public or professional expectations. The authors identify and critique two possible factors contributing to this failure and then offer a model for the development and implementation of primary prevention strategies that addresses these factors. The model used is based on Habermas's theory of communicative action and recognizes the importance of a critical dialogue in health education and health promotion. The primary prevention programs currently being conducted by the Cancer Centre for the Southern Interior are presented as an example of the model in action.

Integrating OASIS data collection into a comprehensive assessment.

OASIS should not be used as a survey tool; rather, it should be integrated into a comprehensive assessment. It is almost never appropriate to simply read OASIS questions verbatim to patients and expect them to name the letter of the response. This article provides strategies for collecting OASIS data as part of a routine patient comprehensive assessment.

Characterization of the exosporium of Bacillus cereus.

Exosporium components from endospores of Bacillus cereus ATCC 10876 were purified and separated by gel electrophoresis. Several of the proteins for which N-terminal sequences were recovered were found to have homologues in protein databases which have been demonstrated to have enzymic activity in other organisms. Amongst these is a zinc metalloprotease, immune inhibitor A, already described in B. thuringiensis. This has been shown to be present in an active 73 kDa form on the exosporium of B. cereus. Other proteins associated with the exosporium include the molecular chaperone GroEL and a homologue of RocA (1-pyrroline-5-carboxylate dehydrogenase (EC 1.5.1.12)) of B. subtilis. Although these are unlikely to represent integral structural proteins of the exosporium, the observation that they are selectively present in the spore surface layer suggests that this layer may have functional significance.

Human immune responses to the UK human anthrax vaccine.

The IgG anti-protective antigen subclass antibody response of individuals who had been infected with anthrax was compared with that of healthy individuals immunized with the UK licensed anthrax vaccine. The predominant subclass in both groups was IgG1. In addition, IgG3 was seen in convalescent serum while vaccinees produced IgG2, IgG3 and IgG4 subclass. The significance of these results is discussed. Further work is required to determine the role of antibodies in mediating protective immunity in man.

Expression of the protective antigen of Bacillus anthracis by Lactobacillus casei: towards the development of an oral vaccine against anthrax.

Bacillus anthracis is the causative organism of the disease anthrax. The ability of the organism to form resistant spores and infect via the aerosol route has led to it being considered as a potential biological warfare agent. The current available human vaccines are far from ideal, they are expensive to produce, require repeated doses and may invoke transient side-effects in some individuals. There is also evidence to suggest that they may not give full protection against all strains of B. anthracis. A new generation of anthrax vaccine is therefore needed. The use of Lactobacillus as a vector for expression of heterologous proteins from pathogens supplies us with a safe system, which can be given orally. Lactobacilli are commensals of the gut, generally regarded as safe and have intrinsic adjuvanticity. Oral vaccines may stimulate the mucosol immune system to produce local IgA responses in addition to systemic responses. These vectors are delivered at the mucosal surface, the site where the infection actually occurs and where the first line of defence lies. The gene encoding the protective antigen (PA) of B. anthracis, an immunogenic non-toxic component of the two toxins produced, is being cloned into different homologous vectors and subsequently transformed to various Lactobacillus strains. High intracellular expression levels for the PA in Lact. casei were achieved. Mucosal antigen presentation and humoral and cellular immune responses following immunization with transformants expressing PA in various ways (intracellular, surface-anchored and extracellular) are being studied.

Presentation of protective antigen to the mouse immune system: immune sequelae.

Protective antigen (PA), the major protective component of the existing vaccine, is a potent immunogen. Protective antigen in alhydrogel induced a high serum IgG titre (> log10 4) in both the C57B16 and Balb/c mouse and the predominant subclass of antibody induced was IgG1, indicating that the response to PA was predominantly Th2 directed. When plasmid DNA encoding PA was used to immunize the Balb/c mouse, a low serum IgG titre was detected (

Preparing adult branch students for their management role as staff nurses: an action research project.

AIM: This action research project aimed to investigate students', newly qualified staff nurses' and ward managers' views about the management skills and knowledge required by staff nurses, and how best students could be prepared for their management role. BACKGROUND: The importance of the staff nurse's management role is increasingly being recognized but the literature highlights the difficulties in preparing students for management, and personal experience confirmed this. METHODS: Focus group interviews were held with senior students and newly qualified staff nurses. A questionnaire was then developed which was completed by 23 ward managers. FINDINGS: A good insight into the management skills and knowledge expected of newly qualified staff nurses, and useful ideas about preparation for the role emerged. An extra 2 weeks in practice, supernumerary and with specific management learning outcomes, was implemented and evaluated well. CONCLUSIONS: Preparation of students for their management role as staff nurses benefits from being closely linked to practical experience, with clear learning outcomes and supportive clinical staff. Using an action research approach to investigate the problem and develop a strategy was found to be an appropriate methodology.

The expression of the protective antigen of Bacillus anthracis in Bacillus subtilis.

The expression of Bacillus anthracis protective antigen (PA) in B. subtilis from the pag gene in pPA101-1 was explored in different genetic backgrounds in an attempt to identify opportunities to maximize expression. Introduction of AtxA, which positively regulates PA expression in B. anthracis did not improve expression levels in the protease-deficient strain WB600. Plasmid pPA101-1 was found to carry a deletion which created a new fusion point between vector and insert sequence, and which removed part of the AtxA binding site. The deletion may have occurred as a consequence of recombination between TCTAT sequences within both the vector and insert. Host mutations could influence expression; PA levels from pPA101-1 are threefold higher in a ccpA mutant than in an otherwise isogenic parent, and eightfold higher in an abrB mutant. These data demonstrate that the introduction of mutations affecting catabolite repression and growth phase regulation results in an increase in the yield of PA in this host-vector system. Combining these mutations with a multiply protease-negative background could potentially allow further improvements in PA yield.