Academic libraries are facing a myriad number of challenges and opportunities ahead. AI is just one example. Paint a picture of the science library of the future – what will it offer to remain core to teaching, learning, research and the overall student experience? How will you, as a leader, prepare the health science and science libraries for that future?
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Abstract
Bioaugmentation has emerged as an effective way to remediate groundwater of anthropogenic contaminants, such as chloroform (CF) and dichloromethane (DCM). The Dehalobacter genus can anaerobically respire many of these chlorinated compounds using reductive dehalogenases, often as part of a heterogenous microbial community. One such community is SC05, which dechlorinates CF completely to carbon dioxide and hydrogen. Despite its effective use at contaminated sites, prior to this work SC05 remained unstudied in terms of taxonomy and broader metabolism, without identification of the active DCM degrader(s?). This thesis seeks to ascertain key microbes in the culture and their metabolic mechanisms using experimental, metagenomic, and metabolic modelling approaches.
A unique characteristic of “self-feeding” is first established in SC05, wherein electron equivalents produced from DCM mineralization are harnessed for CF dechlorination. An SC05 subculture continually dechlorinated CF for over 1400 days with no exogenous electron donor. Dehalobacter was the only bacterial genus that grew in either the CF dechlorination or DCM mineralization phase, implicating it as a key mediator of both CF and DCM degradation. Dehalobacter expressed a single reductive dehalogenase that dechlorinates CF to DCM but has no activity on DCM, as well as the mec cassette—core proteins for DCM degradation. These two modules were within 10 kb in a single genomic neighbourhood.
Two unique Dehalobacter genomes were ultimately assembled, each of which encoded the acd- mec neighbourhood. When assessed pangenomically, this region was designated as a mobile genetic element resulting from horizontal gene transfer between Dehalobacter strains. Each strain could employ this shared genetic cargo to dechlorinate CF and mineralize DCM, with differing dynamics dependant on culture conditions. Genome-scale metabolic models of each strain were curated to predict and compare metabolism during each remediation step.
Overall, this work elucidates some of the former mysteries of SC05, informing considerations for field application such as electron donor demand. It also highlights the importance of hydrogen cycling and microbial syntrophy in anaerobic DCM degradation. Fundamentally, it expands the typical assumptions of the metabolic rigidity of Dehalobacter genus and posits mechanisms of evolution and horizontal gene transfer as it pertains to adaptation of microbial communities to anthropogenic chemicals.
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Abstract: Food fortification programs aim to provide meaningful amounts of micronutrients (e.g., 30%-50% of the daily adult requirements) at the average consumption level of one or more food vehicles. Foods that can be fortified include wheat and wheat products, maize, rice, milk and milk products, cooking oils, salt, sugar, and condiments. New vehicles widely and regularly consumed in certain regions, like bouillon cubes, flavouring sauces, or tea, are also gaining new attention. Micronutrient premixes for home fortification are also being promoted. Depending on the food processing methods, adding the micronutrients can be facilitated using different approaches to maximize nutrient retention. These include dry mixing, dissolution in water/oil, micronization, spraying, adhesion, coating, extrusion, micro-encapsulation, and dry mixing.
Cost, bioavailability, sensory acceptability, and stability (during storage and cooking) are the critical criteria for determining the best match between the nutrient and food vehicle. When added to food or beverage carriers, specific vitamins and minerals could interact with each other and the food, reducing their bioavailability and organoleptic quality. The development of appropriate technology to optimize the effectiveness of fortification needs special attention.
Better refining procedures and packaging have significantly improved the stability of iodine compounds in salt and vitamin A in cooking oils. The structure of the compounds can also be modified to improve absorption. In the case of iron, stabilizers, chelating agents, and absorption enhancers could be added along with the fortificant to retain it in an absorbable form or improve absorption. The extrusion and micro-encapsulation of micronutrients can ensure nutrient stability while ensuring breakdown and absorption in the gut. Technological improvements in the analytical methods for testing fortified foods have been developed specifically to monitor nutrient retention from production to consumption.
Speaker Bio
M.G. Venkatesh Mannar has pioneered several effective international nutrition, technology, and development initiatives focused on the world’s most vulnerable citizens. A chemical engineer and food technologist by training, Mannar served as the President of the Micronutrient Initiative Canada (MI) for nearly 20 years until February 2014. He directed the organization’s mission to develop, implement, and monitor cost-effective and sustainable solutions to address micronutrient deficiencies. Mannar’s work has focused on the world’s most vulnerable citizens, including staple food fortification, vitamin A supplementation, and scale-up of biofortified food production and marketing. His work on iodization and multiple fortification of salt has been scaled up to benefit billions of people worldwide. The double-fortified salt (with iron and iodine) and multiply fortified salts he worked on at the University of Toronto are being scaled in India and other countries. He has co-authored over 100 articles in leading nutrition journals and is the co-editor of ‘Food Fortification in a Globalized World. Mannar pursues research and teaching as an Adjunct Professor at the Centre for Global Engineering at the University of Toronto. He was co-chair of the Independent Expert Group for the Global Nutrition Report 2020 – the leading and most authoritative report on Global Nutrition. He has also served on the Technical Advisory Boards of leading multinational food companies. In 2013, Mannar was appointed an Officer of the Order of Canada, one of the country’s greatest civilian honors, for his leadership in the global fight against malnutrition and micronutrient deficiency. In 2015, the Indo-Canada Chamber of Commerce felicitated him with an Outstanding Lifetime Achievement Award. In Jun 2016, he was conferred with an Honorary Doctor of Science Degree by the University of Toronto.