Day 15 :
- Probiotics, Prebiotics, Apiculture
Location: Webinar
Chair
Hsueh lui Ho
Micron Bio-Systems, UK
Session Introduction
Hsueh lui Ho
Micron Bio-Systems, UK
Title: Saccharomyces cerevisiae as a Mycotoxin Remediator
Biography:
Hsueh lui Ho did her PhD at Imperial College London studying the cell cycle in S. cerevisiae, before researching fungal pathogens at Imperial College London and later the University of Exeter. Over the course of her research, she has gained expertise in microbiology, molecular biology, protein biology, biochemistry, genomics, and in using D. melanogaster and G. mellonella as virulence models for investigating fungal pathogens. Since leaving Academia, Hsueh lui works at Micron Bio-Systems Ltd. investigating the uses of beneficial microbes in the Animal and Agriculture Industry,
Abstract:
Statement of the Problem: One of the major challenges in food sustainability is the spoilage and contamination of crops from secondary metabolites, mycotoxins, produced by fungi. Mycotoxins pose a significant danger to the health and performance of farm livestock and cause a variety of different symptoms including decreased feed intake, poor reproductive performance, reduced milk production and even death. The aim of this study was to investigate whether Saccharomyces cerevisiae could degrade mycotoxins. Methodology[RB1] : 100mg of Saccharomyces cerevisiae (R404) was inoculated in 50ml of nutrient broth with or without 1µg/ml Zearalenone. Samples were incubated at 37oC, at 200rpm for 48 hours. Samples were taken at 0, 1, 2, 3, 4, 5, 6, 7, 8, 24, and 48 hours for mycotoxin analysis. Samples were analyzed using a Waters Acquity UPLC and a Waters Xevo TQ Mass Spectrometer for the presence of Zearalenone and its metabolites. Findings: S. cerevisiae was able to degrade Zearalenone (ZON) to its metabolites α- and β-Zearalenol (ZOL) within 1 hour. The presence of β-ZOL is observed within 1 hour, while the more toxic α-ZOL is detected after 3 hours[RB2] . The less toxic metabolite β-ZOL was produced at a higher concentration than the more toxic α- ZOL. Conclusion & Significance: S. cerevisiae is known to have a probiotic effect in animals and humans and helps to maintain the integrity of the intestinal epithelial lining. In this study, we have shown that S. cerevisiae primarily degrades ZON to its less toxic daughter metabolite β-ZOL. This suggests that S. cerevisiae can be used as a probiotic and mycotoxin remediator in the treatment of animals poisoned with ZON.
Jong H. Kim
Western Regional Research Center, USDA-ARS, USA
Title: Chemo-genetic approaches for improved antifungal intervention
Biography:
Treatment of fungal pathogens such as Aspergillus fumigatus or producers of toxic secondary metabolites, viz., mycotoxins, is increasingly problematic due to the limited number of effective drugs or fungicides available for fungal control. Moreover, the expansion of fungal resistance to commercial drugs or fungicides is a global public health issue. For example, certain azole fungicides that are applied to agricultural fields have the same antifungal mechanism of action as clinical azole drugs. Such long-term application of azole fungicides to farms could provide selection pressure for the emergence of pan-azole-resistant fungal pathogens. Therefore, there is persistent need to enhance the effectiveness of conventional antifungal agents or discover/develop new intervention strategies. Current industry estimation indicates that development of new agrochemicals from discovery to first sale requires 159,574 compounds to be screened on average, where the time and costs for this new development exceed 11 years and $286 million, respectively. We developed chemo-genetic approaches for compound screening to expedite the identification of new, safe antifungal agents. Screening United States Food and Drug Administration (FDA)-classified Generally Recognized As Safe compounds led to the identification of chemicals targeting fungal antioxidant or cell wall integrity systems, which effectively inhibit the growth of pathogens. They possess antifungal, antimycotoxigenic or chemosensitizing capability to enhance the efficacy of conventional antifungal agents. Therefore, our methods can reduce costs, abate resistance, and alleviate negative side effects associated with current antifungal treatments.
Abstract:
Jong H. Kim is a Research Molecular Biologist in the Agricultural Research Service (ARS), US Department of Agriculture, Albany, California. His research focuses on the development of intervention strategies for control of mycotoxigenic and phytopathogenic fungi. He provides chemo-biological expertise, particularly in the identification of cellular targets, mechanisms of action and compound interaction, and participates in resistance management in collaboration with producers, industry and academia.
Ahmed Nawaz
The Open University, UK
Title: Effect of plastics on marine bacterial community composition
Biography:
Ahmed Nawaz is currently a PhD candidate at the The Open University, UK. His work focuses on effect of plastic debris on marine microorganisms and the biodegradation process of these plastics in marine environment.
Abstract:
Plastic debris is ubiquitous in global oceans with its rising production and the underlying impacts of this man-made litter require urgent attention. To learn about the unaccounted consequences of the plastic debris in the ocean, it is crucial to understand how it influences the microbial communities in marine environment that play key roles in ecosystem functioning. Research has shown that microbes readily colonise marine plastic debris and community members of these microbiotas are speculated to have toxic, pathogenic or plastic degradingspecies. However, the role of plastic in selecting for unique microbial communities is largely unknown, as is the influence of colonising microorganisms on the fate of plastic waste. The current study focuses on determining the influence of plastic type on structure and diversity of seawater bacterial communities. Next generation sequencing and community fingerprinting permitted us to characterise communities from natural seawater. Communities were compared with respect to plastics and physico-chemical properties of the marine environment to determine the factors influencing the bacterial communities. Ahmed Nawaz is currently a PhD candidate at the The Open U
Seipati P. Tenyane
Stellenbosch University, South Africa
Title: Saccharomyces cerevisiae-driven evolution reveals yeast-strain specific phenotypic adaptations and genetic changes in Lactobacillus plantarum
Biography:
Seipati P. Tenyane is a PhD student and has her interest in microbial population dynamics and the impact of these microbes on the environment in which they are found. She has expertise in the broader context of molecular microbiology, microbial ecology, evolutionary biology and bioinformatics. Seipati has successfully mapped and annotated the genome of Lactobacillus plantarum IWBT B063. In addition to that, she has helped build a Lb. plantarum gene ontology database which will be useful in determining the molecular responses of these bacteria to various stresses or environments.
Abstract:
Saccharomyces cerevisiae strains are reported to either promote or, most frequently, inhibit lactic acid bacteria strains (LAB). Unfortunately, it is unknown what drives either positive or negative interactions between these strains. To investigate underlying interaction mechanisms between wine-related yeast and bacteria and their impact on malolactic fermentation (MLF), a directed evolution (DE) approach was designed to directly evolve a Lactobacillus plantarum strain using two strains of S. cerevisiae, EC1118 and Cross Evolution, as selective drivers. In this strategy, the bacterial population evolved continuously in co-culture with the inhibitory strains of yeast over successive generations. The yeast population, however, was re-inoculated from the same mother culture for each sequential batch fermentation. In this design, the yeast ‘driver’ strains cannot evolve, and improved growth of the evolving bacterial species is a direct function of their ability to compete with the specific yeast strain. Analysis of evolved isolates from the bacterial populations after only 50 generations revealed surprisingly vast differences in the phenotypes of isolates. The data show increased growth of evolved isolates compared to the parent strain as well as showing yeast-specific phenotypes with regard to the rate of malic acid consumption. Whole-genome sequencing of selected strains was carried out to elucidate the genetic changes which underpin the evolved phenotypes observed. Gene ontology revealed amino acid metabolism as a DE target, with specific gene targets including amino acid biosynthetic process (argD, argJ, carB, hisB, hisE, hutI), glutamine metabolic process (glmS) and amino acid transmembrane transport (glnQ, rocC). To our knowledge, this is the first study to use a biotic selective pressure (S. cerevisiae) to evolve Lb. plantarum for the improvement of MLF and to investigate yeast-bacteria interactions.