Identification of Bartonella species in rodents, shrews and cats in Denmark: detection of two B-henselae variants, one in cats and the other in the long-tailed field mouse

Small mammals and stray cats were trapped in two areas of North Zealand, Denmark, and their blood cultured for hemotrophic bacteria. Bacterial isolates were recovered in pure culture and subjected to 16S rDNA gene sequencing. Bartonella species were isolated from five mammalian species: B. grahamii from Microtus agrestis (field vole) and Apodemus flavicollis (yellow-necked field mouse); B. taylorii from M. agrestis, A. flavicollis and A. sylvaticus (long-tailed field mouse); B. tribocorum from A. flavicollis; R vinsonii subsp. vinsonii from M. agrestis and A. sylvaticus; and B. birtlesii from Sorex vulgaris (common shrew). In addition, two variant types of B. henselae were identified: variant I was recovered from three specimens of A. sylvaticus, and B. henselae variant 11 from I I cats; in each case this was the only B. henselae variant found. No Bartonella species was isolated from Clethrionomys glareolus (bank vole) or Micromys minutus (harvest mouse). These results suggest that B. henselae occurs in two animal reservoirs in this region, one of variant I in A. sylvaticus, which may be transmitted between mice by the tick Ixodes ricinus, and another of variant 11 in cats, which may be transmitted by the cat flea (Ctenocephalides felis). To our knowledge, this is the first report of the occurrence of B. henselae and B. tribocorum in Apodemus mice.

Testing temperature-induced proteomic changes in the plant-associated bacterium Pseudomonas fluorescens SBW25.

Traits used by bacteria to enhance ecological performance in natural environments are not well understood. Recognizing that the saprophytic plant-colonizing bacterium Pseudomonas fluorescens SBW25 experiences temperatures in its natural environment significantly cooler than the 28°C routinely used in the laboratory, we identified proteins differentially expressed between 28°C and the more environmentally relevant temperature of 14°C. Of 2102 protein isoforms, 32 were temperature responsive and identified by mass spectrometry. Seven of these (OmpR, MucD, GuaD, OsmY and three of unknown function, Tee1, Tee2 and Tee3) were selected for genetic and ecological analyses. In each instance, changes in protein expression with temperature were mirrored by parallel transcriptional changes. The fitness contribution of the genes encoding each of the seven proteins was larger at 14°C than 28°C and included two cases of trade-offs (enhanced fitness at one temperature and reduced fitness at the other – mucD and tee2 deletions). The relationship between the fitness effects of genes in vitro and in vivo was variable, but two temperature-responsive genes – osmY and mucD – contribute substantially to the ability of P. fluorescens to colonize the plant environment.

A model study of factors influencing projected changes in regional sea level over the 21st century

In addition to projected increases in global mean sea level over the 21st century, model simulations suggest there will also be changes in the regional distribution of sea level relative to the global mean. There is a considerable spread in the projected patterns of these changes by current models, as shown by the recent Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (AR4). This spread has not reduced from that given by the Third Assessment models. Comparison with projections by ensembles of models based on a single structure supports an earlier suggestion that models of similar formulation give more similar patterns of sea level change. Analysing an AR4 ensemble of model projections under a business-as-usual scenario shows that steric changes (associated with subsurface ocean density changes) largely dominate the sea level pattern changes. The relative importance of subsurface temperature or salinity changes in contributing to this differs from region to region and, to an extent, from model-to-model. In general, thermosteric changes give the spatial variations in the Southern Ocean, halosteric changes dominate in the Arctic and strong compensation between thermosteric and halosteric changes characterises the Atlantic. The magnitude of sea level and component changes in the Atlantic appear to be linked to the amount of Atlantic meridional overturning circulation (MOC) weakening. When the MOC weakening is substantial, the Atlantic thermosteric patterns of change arise from a dominant role of ocean advective heat flux changes.

Changes in the intestinal microbiota after a short period of dietary over-indulgence, representative of a holiday or festival season

The effects on the intestinal microbiota of a short period of marginal over-eating, characteristic of holiday or festival periods, were investigated in a pilot study. Fourteen healthy male subjects consumed a diet rich in animal protein and fat for seven days. During this period, the subjects significantly increased their dietary energy, protein, carbohydrate and fat intakes by 56, 59, 53 and 58%, respectively (all P < 0.05). The mean weight gain of 0.27 kg was less than the expected 1 kg, but this was consistent with a degree of under-reporting on the baseline diet. Fluorescence in situ hybridisation analysis confirmed the relative stability of each individual’s faecal microbiota but showed considerable variations between them. The diet was associated with a significant increase in numbers of total faecal bacteria and the bacteroides group, as detected by the universal bacterial probe (DAPI) and Bacteroides probe (Bac 303), respectively. Overall, there was a decrease in numbers of the Lactobacillus/Enterococcus group (Lab 158 probe; 2.8 ± 3.0% to 1.8 ± 1.8%) and the Bifidobacterium group (Bif 164 probe; 3.0 ± 3.7% to 1.7 ± 1.2%), although there was considerable inter-individual variation. Analysis of the relative proportions of each bacterial group as a percentage of the subject’s total bacteria showed a trend for a change in the intestinal microbiota that might be considered potentially unhealthy.

The changing atmospheric water cycle in polar regions in a warmer climate

We have examined the atmospheric water cycle of both Polar Regions, pole wards of 60°N and 60°S, using the ERA-Interim re-analysis and high-resolution simulations with the ECHAM5 model for both the present and future climate based on the IPCC, A1B scenario, representative of the last three decades of the 21st century. The annual precipitation in ERA-Interim amounts to ~17000 km3 and is more or less the same in the Arctic and the Antarctic, but it is composed differently. In the Arctic the annual evaporation is some 8000 km3 but some 3000 km3 less in the Antarctica where the net horizontal transport is correspondingly larger. The net water transport of the model is more intense than in ERA-Interim, in the Arctic the difference is 2.5% and in the Antarctic it is 6.2%. Precipitation and net horizontal transport in the Arctic has a maximum in August and September. Evaporation peaks in June and July. The seasonal cycle is similar in Antarctica with the highest precipitation in the austral autumn. The largest net transport occurs at the end of the major extra-tropical storm tracks in the Northern Hemisphere such as the eastern Pacific and eastern north Atlantic. The variability of the model is virtually identical to that of the re-analysis and there are no changes in variability between the present climate and the climate at the end of the 21st century when normalized with the higher level of moisture. The changes from year to year are substantial with the 20 and 30-year records being generally too short to identify robust trends in the hydrological cycle. In the A1B climate scenario the strength of the water cycle increases by some 25% in the Arctic and by 19% in the Antarctica, as measured by annual precipitation. The increase in the net horizontal transport is 29% and 22% respectively, and the increase in evaporation correspondingly less. The net transport follows closely the Clausius-Clapeyron relation. There is 2 a minor change in the annual cycle of the Arctic atmospheric water cycle with the maximum transport and precipitation occurring later in the year. There is a small imbalance of some 4-6% between the net transport and precipitation minus evaporation. We suggest that this is mainly due to the fact the transport is calculated from instantaneous 6-hourly data while precipitation and evaporation is accumulated over a 6 hour period. The residual difference is proportionally similar for all experiments and hardly varies from year to year.

Recognition of greater diversity of Bacillus species and related bacteria in human faeces

In a study looking at the culturable, aerobic Actinobacteria associated with the human gastrointestinal tract, the vast majority of isolates obtained from dried human faeces belonged to the genus Bacillus and related bacteria. A total of 124 isolates were recovered from the faeces of 10 healthy adult donors. 16S rRNA gene sequence analyses showed the majority belonged to the families Bacillaceae (n = 81) and Paenibacillaceae (n = 3), with Bacillus species isolated from all donors. Isolates tentatively identified as Bacillus clausii (n = 32) and B. licheniformis (n = 28) were recovered most frequently, with the genera Lysinibacillus, Ureibacillus, Oceanobacillus, Ornithinibacillus and Virgibacillus represented in some donors. Phenotypic data confirmed the identities of isolates belonging to well-characterized species. Representatives of the phylum Actinobacteria were recovered in much lower numbers (n = 11). Many of the bacilli exhibited antimicrobial activity against one or more strains of Clostridium difficile, C. perfringens, Listeria monocytogenes and Staphylococcus aureus, with some (n = 12) found to have no detectable cytopathic effect on HEp-2 cells. This study has revealed greater diversity within gut-associated aerobic spore-formers than previous studies, and suggests that bacilli with potential as probiotics could be isolated from the human gut.

Miniature transposable sequences are frequently mobilized in the bacterial plant pathogen Pseudomonas syringae pv. phaseolicola

Mobile genetic elements are widespread in Pseudomonas syringae, and often associate with virulence genes. Genome reannotation of the model bean pathogen P. syringae pv. phaseolicola 1448A identified seventeen types of insertion sequences and two miniature inverted-repeat transposable elements (MITEs) with a biased distribution, representing 2.8% of the chromosome, 25.8% of the 132-kb virulence plasmid and 2.7% of the 52-kb plasmid. Employing an entrapment vector containing sacB, we estimated that transposition frequency oscillated between 2.661025 and 1.161026, depending on the clone, although it was stable for each clone after consecutive transfers in culture media. Transposition frequency was similar for bacteria grown in rich or minimal media, and from cells recovered from compatible and incompatible plant hosts, indicating that growth conditions do not influence transposition in strain 1448A. Most of the entrapped insertions contained a full-length IS801 element, with the remaining insertions corresponding to sequences smaller than any transposable element identified in strain 1448A, and collectively identified as miniature sequences. From these, fragments of 229, 360 and 679-nt of the right end of IS801 ended in a consensus tetranucleotide and likely resulted from one-ended transposition of IS801. An average 0.7% of the insertions analyzed consisted of IS801 carrying a fragment of variable size from gene PSPPH_0008/PSPPH_0017, showing that IS801 can mobilize DNA in vivo. Retrospective analysis of complete plasmids and genomes of P. syringae suggests, however, that most fragments of IS801 are likely the result of reorganizations rather than one-ended transpositions, and that this element might preferentially contribute to genome flexibility by generating homologous regions of recombination. A further miniature sequence previously found to affect host range specificity and virulence, designated MITEPsy1 (100-nt), represented an average 2.4% of the total number of insertions entrapped in sacB, demonstrating for the first time the mobilization of a MITE in bacteria.

Targeted observations of a polar low in the Norwegian sea

A developing polar low is targeted with dropsonde observations to improve the forecast of its landfall. Accurately forecasting a polar low's strength and location remains a challenge; polar lows form over the ocean in poorly observed regions, therefore initial condition errors may contribute significantly to forecast error. The targeted polar low formed in the Norwegian Sea on 3 March 2008, during the Norwegian IPY-THORPEX field campaign. Two flights, six hours apart, released dense networks of dropsondes into a sensitive region covering the polar low and Arctic front to its west. The impact of the targeted observations is assessed using the limited-area Met Office Unified Model and three-dimensional variational (3D-Var) data assimilation scheme. Forecasts were verified using ECMWF analysis data, which show good agreement with both dropsonde data from a flight through the mature polar low, and 10 m QuikSCAT winds. The impact of the targeted data moved southwards with the polar low as it developed and then hit the Norwegian coast after 24 hours. The results show that the forecast of the polar low is sensitive to the initial conditions; targeted observations from the first flight did not improve the forecast, but those from the second flight clearly improved the forecast polar low position and intensity. However, caution should be applied to attributing the forecast improvement to the assimilation of the targeted observations from a single case-study, especially in this case as the forecast improvement is moderate relative to the spread from an operational ensemble forecast

Recommendations for the viability assessment of probiotics as concentrated cultures and in food matrices

Due to the fact that probiotic cells need to be alive when they are consumed, culture-based analysis (plate count) is critical in ascertaining the quality (numbers of viable cells) of probiotic products. Since probiotic cells are typically stressed, due to various factors related to their production, processing and formulation, the standard methodology for total plate counts tends to underestimate the cell numbers of these products. Furthermore, products such as microencapsulated cultures require modifications in the release and sampling procedure in order to correctly estimate viable counts. This review examines the enumeration of probiotic bacteria in the following commercial products: powders, microencapsulated cultures, frozen concentrates, capsules, foods and beverages. The parameters which are specifically examined include: sample preparation (rehydration, thawing), dilutions (homogenization, media) and plating (media, incubation) procedures. Recommendations are provided for each of these analytical steps to improve the accuracy of the analysis. Although the recommendations specifically target the analysis of probiotics, many will apply to the analysis of commercial lactic starter cultures used in food fermentations as well.

An investigation of the expression and adhesin function of H7 flagella in the interaction of Escherichia coli O157: H7 with bovine intestinal epithelium

Enterohaemorrhagic Escherichia coli O157 : H7 is a bacterial pathogen that can cause haemorrhagic colitis and haemolytic uremic syndrome. In the primary reservoir host, cattle, the terminal rectum is the principal site of E. coli O157 colonization. In this study, bovine terminal rectal primary epithelial cells were used to examine the role of H7 flagella in epithelial adherence. Binding of a fliC(H7) mutant O157 strain to rectal epithelium was significantly reduced as was binding of the flagellated wild-type strain following incubation with H7-specific antibodies. Complementation of fliC(H7) mutant O157 strain with fliC(H7) restored the adherence to wild-type levels; however, complementation with fliC(H6) did not restore it. High-resolution ultrastructural and imunofluorescence studies demonstrated the presence of abundant flagella forming physical contact points with the rectal epithelium. Binding to terminal rectal epithelium was specific to H7 by comparison with other flagellin types tested. In-cell Western assays confirmed temporal expression of flagella during O157 interaction with epithelium, early expression was suppressed during the later stages of microcolony and attaching and effacing lesion formation. H7 flagella are expressed in vivo by individual bacteria in contact with rectal mucosa. Our data demonstrate that the H7 flagellum acts as an adhesin to bovine intestinal epithelium and its involvement in this crucial initiating step for colonization indicates that H7 flagella could be an important target in intervention strategies.

Simulated anthropogenic changes in the Brewer–Dobson circulation, including its extension to high latitudes

Recent studies using comprehensive middle atmosphere models predict a strengthening of the Brewer-Dobson circulation in response to climate change. To gain confidence in the realism of this result it is important to quantify and understand the contributions from the different components of stratospheric wave drag that cause this increase. Such an analysis is performed here using three 150-yr transient simulations from the Canadian Middle Atmosphere Model (CMAM), a Chemistry-Climate Model that simulates climate change and ozone depletion and recovery. Resolved wave drag and parameterized orographic gravity wave drag account for 60% and 40%, respectively, of the long-term trend in annual mean net upward mass flux at 70 hPa, with planetary waves accounting for 60% of the resolved wave drag trend. Synoptic wave drag has the strongest impact in northern winter, where it accounts for nearly as much of the upward mass flux trend as planetary wave drag. Owing to differences in the latitudinal structure of the wave drag changes, the relative contribution of resolved and parameterized wave drag to the tropical upward mass flux trend over any particular latitude range is highly sensitive to the range of latitudes considered. An examination of the spatial structure of the climate change response reveals no straightforward connection between the low-latitude and high-latitude changes: while the model results show an increase in Arctic downwelling in winter, they also show a decrease in Antarctic downwelling in spring. Both changes are attributed to changes in the flux of stationary planetary wave activity into the stratosphere.

The potential mechanisms involved in the anti-carcinogenic action of probiotics

Probiotic bacteria are live microbial food ingredients that provide a health benefit to the consumer. In the past it was suggested that they served to benefit the host primarily through the prevention of intestinal infections. More recent studies have implicated probiotic bacteria in a number of other beneficial effects within the host including: *The suppression of allergies. *Control of blood cholesterol levels. *Modulation of immune function. *And the prevention of cancers of the colon. The reputed anti-carcinogenic effect of probiotics arises from in vivo studies in both animals and to a limited extent in man; this evidence is supported by in vitro studies with carcinoma cell lines and anti-mutagenicity assays. However, the mechanisms involved in any effect have thus far been difficult to elucidate; studies offer evidence for a variety of mechanisms; we have reviewed these and come to the opinion that, the anti-carcinogenic effect may not be attributable to a single mechanism but rather to a combination of events not yet fully elucidated or understood.

The role of fimbriae and flagella in the colonization, invasion and persistence of Escherichia coli O78 : K80 in the day-old-chick model

To understand the role of flagella and fimbriae of Escherichia coli O78:K80 in avian colibacillosis, day-old chicks were dosed orally with defined afimbriate and or aflagellate mutants and colonization, invasion and persistence compared with that of the wild-type. In an invasion model, chicks were dosed with 1 x 10(5) c.f.u. of a single strain and mutants defective for type 1 fimbriae, curli fimbriae or flagella colonized livers by 24 h although the numbers of bacteria present were significantly less than the wild-type, Mutants colonized between 50 and 75 % of spleens whereas the wild-type colonized 100 % of spleens. Additionally, the numbers of mutant bacteria in colonized spleens were significantly less than the wild-type. Surprisingly, mutants defective for the elaboration of more than one appendage were no more attenuated than single mutants. In a persistence model, chicks were dosed with 1 x 10(2) c.f.u. of a single strain and mutants defective for type 1 or curli or flagella or any combination thereof persisted as assessed by cloacal swabbing for 5 weeks of the experiment less well than the wild-type. In an additional persistence model, chicks were dosed with 5 x 10(2) c.f.u. of each of wild-type and one mutant together. All mutants were significantly less persistent than the wild-type (P < 0.001) and one mutant which lacked type 1, curli and flagella, was eliminated within 2 weeks. Analysis of the trends of elimination indicated that flagella contributed to persistence more than curli, which contributed more than type 1 fimbriae. Here was evidence for a major role in colonization, invasion and persistence played by type 1, curli and flagella.

The role of SEF14 and SEF17 fimbriae in the adherence of Salmonella enterica serotype Enteritidis to inanimate surfaces

To gain an understanding of the role of fimbriae and flagella in the adherence of Salmonella enterica serotype Enteritidis to inanimate surfaces, the extent of adherence of viable wild-type strains to a polystyrene microtitration plate was determined by a crystal violet staining assay, Elaboration of surface antigens by adherent bacteria was assayed by fimbriae- and flagella-specific ELISAs, Wild-type Enteritidis strains adhered well at 37 degrees C and 25 degrees C when grown in microtitration wells in Colonisation Factor Antigen broth, but not in other media tested, At 37 degrees C, adherent bacteria elaborated copious quantities of SEF14 fimbrial antigen, whereas at 25 degrees C adherent bacteria elaborated copious quantities of SEF17 fimbrial antigen. Non-fimbriate and non-flagellate knock-out mutant strains were also assessed in the adherence assay. Mutant strains unable to elaborate SEF14 and SEF17 fimbriae adhered poorly at 37 degrees C and 25 degrees C, respectively, but adherence was not abolished. Non-motile mutant strains showed reduced adherence whilst type-1, PEF and LPF fimbriae appeared not to contribute to adherence in this assay. These data indicate that SEF17 and SEF14 fimbriae mediate bacterial cell aggregation on inanimate surfaces under appropriate growth conditions.

Variation in the persistence of Escherichia coli O157:H7 in experimentally inoculated 6-week-old conventional lambs

Six-week-old lambs were inoculated orally with 10(9) cfu of an antibiotic-resistance marked four-strain mixture of enterohaemorrhagic Escherichia coli (EHEC) O157:H7 to investigate faecal excretion and intestinal colonisation. In the first experiment, three E. coli O157:H7 isolates were not detected in the faeces of any lambs beyond day 8 post inoculation (pi), or from any of the tissues derived from inoculated animals. One strain, 140065 Nal(r), was isolated from the caecum and colon of one lamb on day 9 pi, from the rectum of another on day 22 pi and persisted in the faeces for up to 28 days pi. All animals remained clinically normal throughout the study period and histological evidence of adhesion of E. coli O157:H7 to the intestinal mucosa was not found. In a separate experiment, four 6-week-old lambs were inoculated orally with 10(9) efu of E. coli O157:H7 strain 140065 Nal(r) alone. Faecal samples were positive for this strain until the end of the experiment (day 19 pi). This strain was also recovered from the gastrointestinal tract of lambs on days 6, 18 and 19 pi, but was not isolated at day 17 pi. When sampled separately, rectum and terminal colon contents contained higher numbers of the inoculated strain than the intestinal tissue at these sites. Animals inoculated with O157:117 strain 140065 Nal(r) alone produced soft faeces from day 5 pi onwards. Although attaching and effacing lesions were observed in the caecum, proximal colon and rectum in one animal on day 18 pi, the adherent bacteria did not stain with antiserum raised against the O157 antigen.