University of Guelph

About: University of Guelph is a education organization based out in Guelph, Ontario, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 26542 authors who have published 50553 publications receiving 1715255 citations. The organization is also known as: U of G & Guelph University.

Stool substitute transplant therapy for the eradication of Clostridium difficile infection: 'RePOOPulating' the gut.

Abstract: Fecal bacteriotherapy (‘stool transplant’) can be effective in treating recurrent Clostridium difficile infection, but concerns of donor infection transmission and patient acceptance limit its use. Here we describe the use of a stool substitute preparation, made from purified intestinal bacterial cultures derived from a single healthy donor, to treat recurrent C. difficile infection that had failed repeated standard antibiotics. Thirty-three isolates were recovered from a healthy donor stool sample. Two patients who had failed at least three courses of metronidazole or vancomycin underwent colonoscopy and the mixture was infused throughout the right and mid colon. Pre-treatment and post-treatment stool samples were analyzed by 16 S rRNA gene sequencing using the Ion Torrent platform. Both patients were infected with the hyper virulent C. difficile strain, ribotype 078. Following stool substitute treatment, each patient reverted to their normal bowel pattern within 2 to 3 days and remained symptom-free at 6 months. The analysis demonstrated that rRNA sequences found in the stool substitute were rare in the pre-treatment stool samples but constituted over 25% of the sequences up to 6 months after treatment. This proof-of-principle study demonstrates that a stool substitute mixture comprising a multi-species community of bacteria is capable of curing antibiotic-resistant C. difficile colitis. This benefit correlates with major changes in stool microbial profile and these changes reflect isolates from the synthetic mixture. Clinical trial registration number: CinicalTrials.gov NCT01372943

Adaptive variation in the vulnerability of woody plants to xylem cavitation

Abstract: The ability of plants to supply water to their leaves is intimately associated with survival. Water supply to leaves depends on maintaining an intact water column in the xylem from the roots to shoots. Because this hydraulic pathway is under tension, it is vulnerable to breakage through the induction of air emboli (cavitation). Although the phys- iological benefit of resistance to water-stress-induced xylem cavitation for desiccation tol- erance is clear, there is considerable interspecific variation within and across climates. To understand the adaptive significance of this variation and the potential trade-off with water transport, we compiled a database of 167 species from 50 seed plant families and examined relationships among resistance to xylem cavitation, water transport capacity (as determined by the specific conductivity of xylem ( KS)), and climate. Relationships were evaluated using standard cross-species correlations ( r). Because inferences about the adaptive significance of these correlations can be biased by the potential similarity of closely related species, we also analyzed our data using phylogenetically independent contrast correlations (PIC) calculated over a range of alternate seed plant phylogenies. Resistance to cavitation, ex- pressed as the xylem tension at which 50% of hydraulic conductivity was lost (C50), ranged from 20.18 to 29.9 MPa for angiosperms and from 21.5 to 214.1 MPa for conifers. Conifers were most resistant to cavitation, with mean C50 80% more negative than angio- sperms. In contrast, KS was 270% higher in angiosperms than conifers. Across all species, cavitation resistance increased with decreasing mean annual precipitation. However, sig- nificant phylogenetically independent contrast correlations between C50 and annual precip- itation were found within the evergreen angiosperms and conifers but not in the deciduous angiosperms. Thus, the adaptive significance of increased resistance to cavitation as a mechanism of drought tolerance may be of primary importance in evergreen angiosperms and conifers. In contrast, analysis of independent contrasts indicated that KS increased with decreasing rainfall in deciduous angiosperms, whereas there was no association between KS and water availability for evergreen angiosperms and conifers. These results suggest that the evolution of increased KS may be a critical adaptation to water limitation in de- ciduous angiosperms. Although there was a significant cross-species correlation between C50 and KS, this relationship was not supported by the independent contrast correlation, suggesting that the evolutionary basis for a trade-off between cavitation resistance and water transport capacity is weak.

Enumeration of bacteriophages by double agar overlay plaque assay.

Abstract: The determination of the concentration of infectious phage particles is fundamental to many protocols in phage biology, genetics, and molecular biology. In this chapter the classical overlay protocol is described.

The science of adaptation: a framework for assessment

Abstract: This paper outlines what is meant by "adaptation" to climate change, and how it might be addressed in the IPCC Assessments. Two roles of adaptation in the climate change field are identified: adaptation as part of impact assessment (where the key question is: what adaptations are likely?), and adaptation as part of the policy response (where the central question is: what adaptations are recommended?). The concept of adaptation has been adopted in several fields including climate impact assessment and policy development, risk management, and natural hazards research. A framework for systematically defining adaptations is based on three questions: (i) adaptation to what? (ii) who or what adapts? and (iii) how does adaptation occur? The paper demonstrates that, for adaptation purposes, climate extremes and variability are integral parts of climate change, along with shifts in mean conditions. Attributes for differentiating adaptations include purposefulness, timing, temporal and spatial scope, effects, form and performance. The framework provides a guide for the treatment of adaptation in the IPCC assessments, both in the assessment of impacts and in the evaluation of adaptive policy options.

Agricultural benefits and environmental risks of soil fertilization with anaerobic digestates: a review.

Abstract: Intensive soil fertilization with mineral fertilizers has led to several issues such as high cost, nitrate pollution and loss of soil carbon. Fertilization with organic matter such as compost therefore represents an alternative for sustainable agriculture. Traditional organic amendments such as manures, composts and sewage sludge have been extensively studied in the past. However, applications of biogas digestates and their impacts on the environment and human health are still unexplored. Recent articles report the agricultural potential and conflicting results of digestate performances. As a consequence, the effectiveness of digestate as organic amendment and fertilizer is still under debate. Here we review the legislative, chemical, agronomic and environmental literature on anaerobic digestates. We found that digestates can be considered as organic amendments or organic fertilizers, when properly handled and managed. Indeed we further show that anaerobic digestates have a higher potential to harm the environment and human health than undigested animal manures and slurries. The main points are the following: (1) Most solid digestates comply with the European organic matter minimal requirement for an organic amendment; (2) the fertilizer values of liquid digestates lie between those of livestock manures and inorganic fertilizers; (3) anaerobic digestates have higher NH3 emission potential than undigested animal manures and slurries and, consequently, pose a greater risk to the broad environment; (4) high Cu and Zn concentrations in digestates from co-digestion of pig and cattle slurry feedstock could jeopardize the sustainability of agricultural soils and (5) high Mn concentrations in digestates can induce Mn toxicity in agricultural soils, upon repeated applications.