Factors associated with Echinococcus multilocularis infection in coyotes in southern Ontario

Echinococcus multilocularis was recently reported in wild canids across southern Ontario, a newly recognized endemic area in Canada. In such areas, a comprehensive understanding of factors associated with infection in definitive hosts (wild canids) is critical for mitigating risk of transmission to humans. However, little is known about the transmission dynamics of the parasite in definitive hosts for this region. A study was therefore carried out to investigate the association of host‐level (sex, body condition), environmental (southern Ontario region, land cover), temporal (season, hunting season, calendar year) and extraneous factors (submitter type) with E. multilocularis infection in coyotes in southern Ontario. Between November 2015 and March 2017, 416 coyotes were collected from across the region as part of a study that investigated the prevalence and distribution of the parasite in wild canids; approximately 24% of coyotes were positive for E. multilocularis. Associations between infection and factors of interest were assessed via a mixed‐effects logistic regression model with a random intercept for submitter to account for clustering. Coyotes with poor body condition were at greater odds of E. multilocularis infection than those in good condition (odds ratio [OR] 2.14; 95% CI: 1.08–4.26; p = .030). A negative association was observed between infection in coyotes and the proportion of natural land in a coyote's estimated home range (OR: 0.67; 95% CI: 0.52–0.85; p = .001). Coyotes from the western region of southern Ontario had lower odds of infection compared to coyotes from the central region (OR: 0.26; 95% CI: 0.12–0.55; p < .001). These results can be used to help guide future public health prevention strategies for human alveolar echinococcosis.     

Identification of a universal Group B streptococcus vaccine by multiple genome screen

Group B Streptococcus (GBS) is a multiserotype bacterial pathogen representing a major cause of life-threatening infections in newborns. To develop a broadly protective vaccine, we analyzed the genome sequences of eight GBS isolates and cloned and tested 312 surface proteins as vaccines. Four proteins elicited protection in mice, and their combination proved highly protective against a large panel of strains, including all circulating serotypes. Protection also correlated with antigen accessibility on the bacterial surface and with the induction of opsonophagocytic antibodies. Multigenome analysis and screening described here represent a powerful strategy for identifying potential vaccine candidates against highly variable pathogens.     

Aggregate stability and microbial community dynamics under drying-wetting cycles in a silt loam soil

Aggregate stability often exhibits a large inter-annual and seasonal variability which occurs regardless of residue treatments and is often larger than the differences between soils or cropping systems. Variations in soil moisture and seasonal stimulation of microbial activity are frequently cited as the major causes. The goal of this paper was to evaluate the effects of drying-rewetting cycles on aggregate stability and on its main microbially mediated agents from a mechanistic point of view. The 3-5 mm aggregates of a silty soil were incubated at 20 °C for 63 days with the following treatments and their combinations: (i) with or without straw input and (ii) with or without exposure to four dry-wet cycles. Microbial activity was followed by measuring the soil respiration. We estimated the microbial agents of aggregate stability measuring hot-water extractable carbohydrate-C, microbial biomass carbon and ergosterol content. We measured the water drop penetration time to estimate the hydrophobicity and aggregate stability according to Le Bissonnais [1996. Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology. European Journal of Soil Science 47, 425-437] to distinguish three breakdown mechanisms: slaking, mechanical breakdown and microcracking. The addition of straw stimulated microbial activity and increased the resistance to the three tests of aggregate stability, enhancing the internal cohesion and hydrophobicity of aggregates. All the estimated microbial agents of aggregate stability responded positively to the addition of organic matter and were highly correlated with aggregate stability. Fungal biomass correlated better with aggregate stability than total microbial biomass did, showing the prominent role of fungi by its triple contribution: physical entanglement, production of extracellular polysaccharides and of hydrophobic substances. Dry-wet cycles had less impact on aggregate stability than the addition of straw, but their effects were more pronounced when microbial activity was stimulated demonstrating a positive interaction.     

Effect of 1-methylcyclopropene on volatile emission and aroma in cv. Anna apples

The rapidly ripening summer apple cultivar Anna was treated with 0.1 micro L(-1) and 1 microL L(-1) 1-methylcyclopropene (MCP) at harvest and kept at 20 degrees C, or stored for 5 weeks at 0 degrees C and then transferred to 20 degrees C. Total volatiles were not reduced by treatment with 0.1 microL L(-1) MCP, but were 70% lower in fruits treated with 1 microL L(-1) MCP than in untreated fruits. Ethylene production was 50% and 95% inhibited by 0.1 microL L(-1) and 1 microL L(-1) MCP, respectively. The volatiles produced by fruit at harvest were predominantly aldehydes and alcohols, with some acetate esters as well as 2-methyl butyl acetate and beta-damascenone. During ripening, the acetate and butyrate esters increased greatly and alcohols and aldehydes decreased. MCP-treated apples retained more alcohols, aldehydes, and beta-damascenone volatiles than did untreated apples. Sensory evaluation found that control and 0.1 microL L(-1) treated apples developed more fruity, ripe, and overall aromas, but the preference was for the 1 microL L(-1) treated apples with a less ripe aroma.     

Edge effects and arboreal Collembola in coniferous plantations

We report on the distribution of arboreal Collembola in relation to canopy microclimatic conditions and distance from a forest edge. Collembola were collected by pyrethrum misting from the canopy of 12 m commercial plantations of Pinus sylvestris and Picea sitchensis at two sites in northern England, using transects running perpendicularly from a sharp edge (against open moorland). Temperature and humidity were co-recorded at 1.5 m elevation. Eleven species of Collembola were recorded, dominated by four known to be arboreal (Entomobrya nivalis, Lepidocyrtus lanuginosus, Vertagopus arboreus and Anurophorus laricis) but also including small numbers of supposedly edaphic forms, notably Protaphorura armata. All species were at higher density in the P. sitchensis plantations, but otherwise displayed no consistent community structure. Only four significant edge effects were detected in the Collembola data (out of 60 tests), none of which fitted an exponential model. By contrast the majority of the micro-meteorological data showed significant edge effects which were well modelled by an exponential function. It is concluded that the distribution of arboreal Collembola showed no edge effects, despite the latter being detectable in their meteorological environment.     

DNOC, a model pollutant, adversely affects the potential of soil microbial communities to mineralise the herbicide 2,4-D: an investigation using micro-sampling procedures

The effects of the herbicide, DNOC, 4,6-dinitro-o-cresol, a model pollutant, have been studied by comparing the potential of soil microbial communities present in individual soil aggregates or in larger soil microcosms as samples of soil aggregates to mineralise the herbicide 2,4-D. We have shown that 2-3 mm soil aggregates vary widely in their 2,4-D mineralisation potential and that ageing or exposure to DNOC considerably simplified the distribution patterns of this capacity. The main factors of variation have been quantified and classified using a quasi-likelihood method derived from the Generalised Linear Model approach. Besides DNOC concentration and duration of exposure, an additional ‘rank’ factor reflecting a desiccation gradient of the aggregates on the microtiter plates was found to have statistical significance. We concluded that it should be possible to derive an experimental approach, designated as ‘functional profiling’, with potential use to detect soil chemical contamination. Curves of 2,4-D mineralisation in individual soil aggregates could be classified according to three different types of kinetics, which were assumed to reflect heterogeneous spatial distribution, differences in microbial community composition and varying efficiency of the microbial consortia involved in 2,4-D degradation. Exposure to DNOC considerably simplified the distribution patterns of the different types of kinetics with one type, showing slow rate and low cumulative mineralisation, becoming predominant as ageing, concentration and duration of DNOC exposure increased. We argue on the possible use of ‘kinetic profiling’ as a sensitive bioindicator of soil quality. By comparison, in soil microcosms, 2,4-D mineralisation showed an extra mineralisation potential of 64% over individual aggregates in the control soil and exposure to DNOC was followed by concentration and time-dependent recovery of the 2,4-D mineralisation potential. It is likely that 2 g size soil microcosms gather a larger number of biochemical capacities which could complement each other to increase the potential of soil to mineralise xenobiotic compounds.