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You searched for subject:(Iturin). Showing records 1 – 3 of 3 total matches.

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Cornell University

1. Crane, Julia. Ecology Of Bacillus On Wheat Florets: Insights For Improved Biological Control On Aerial Plant Surfaces .

Degree: 2014, Cornell University

The biological control agent Bacillus amyloliquefaciens strain TrigoCor provides significant and consistent control of Fusarium head blight in greenhouse settings but not in field environments. To investigate potential ecological factors contributing to the poor performance of TrigoCor in field trials, we measured the levels of Bacillus populations and of a critical Bacillus-produced antifungal metabolite, iturin, on wheat spikes in the greenhouse and the field for 14 days post-TrigoCor application. We found that on wheat spikes in both environments, the levels of Bacillus populations remained fairly stable throughout the sampling period, but the levels of iturins declined drastically by 3 days post-application. Results from greenhouse trials and antibiosis assays indicated that the biological activity of TrigoCor-synthesized compounds was close to the minimum threshold needed for successful Fusarium graminearum inhibition and disease suppression. The decline observed for iturins on wheat spikes is therefore likely limiting for disease control, particularly in field environments where natural Fusarium infections can occur for a period of over 10 days post-anthesis. To increase the production of iturins on wheat spikes, we sought to stimulate the germination of metabolically dormant Bacillus spores present on wheat surfaces. Using the terbium chloride assay and phase contrast microscopy, we screened potential nutrient germinants of TrigoCor spores at room temperature and at 37 [MASCULINE ORDINAL INDICATOR]C, and identified two germinant combinations that produced high levels of TrigoCor spore germination in vitro. One of these germinant combinations, consisting of an equimolar mixture of L-asparagine, D-glucose, D-fructose, and potassium chloride, also produced significant Bacillus germination on wheat surfaces. However, neither germinant combination was able to significantly improve disease control with TrigoCor spores in greenhouse settings, in one case likely due to its stimulatory effect on Fusarium growth. Finally, we used epifluorescent stereomicroscopy and confocal laser scanning microscopy to visualize the spatial distribution of TrigoCor inoculum on wheat spikes post-application, and found that the coverage of inoculum sprayed onto wheat spikes in the greenhouse was much higher than that in the field. We also observed that significant inhibition of Fusarium ascospores only occurred when the spores were in direct contact with TrigoCor inoculum droplets. Inadequate spray coverage of wheat spikes in field settings may therefore limit disease control in this environment by leaving large regions of the wheat spike unprotected against Fusarium germination and colonization. Future optimization efforts for above-ground biological control with Bacillus should focus on improving in situ metabolite production by Bacillus, as well as on increasing application coverage on plant surfaces in the field. Bacillus biological control might be best suited for diseases with short, predictable infection periods or where multiple… Advisors/Committee Members: Angert, Esther R. (committeeMember), Gibson, Donna Marie (committeeMember), Cox, William Joseph (committeeMember).

Subjects/Keywords: iturin; wheat; Fusarium head blight

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Crane, J. (2014). Ecology Of Bacillus On Wheat Florets: Insights For Improved Biological Control On Aerial Plant Surfaces . (Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/36096

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Crane, Julia. “Ecology Of Bacillus On Wheat Florets: Insights For Improved Biological Control On Aerial Plant Surfaces .” 2014. Thesis, Cornell University. Accessed April 06, 2020. http://hdl.handle.net/1813/36096.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Crane, Julia. “Ecology Of Bacillus On Wheat Florets: Insights For Improved Biological Control On Aerial Plant Surfaces .” 2014. Web. 06 Apr 2020.

Vancouver:

Crane J. Ecology Of Bacillus On Wheat Florets: Insights For Improved Biological Control On Aerial Plant Surfaces . [Internet] [Thesis]. Cornell University; 2014. [cited 2020 Apr 06]. Available from: http://hdl.handle.net/1813/36096.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Crane J. Ecology Of Bacillus On Wheat Florets: Insights For Improved Biological Control On Aerial Plant Surfaces . [Thesis]. Cornell University; 2014. Available from: http://hdl.handle.net/1813/36096

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Silva, Mara Teresa Caldeira da. Novel biocides for cultural heritage.

Degree: 2017, Universidade de Évora

Many microorganisms, influenced by environmental conditions, are the main responsible for biological contamination in built heritage. Biocides based on chemical toxic compounds have been the most often used to mitigate this problem. Thus, it is of vital importance to develop proper remediation actions based on environmentally innocuous alternatives. Bacteria of the genera Bacillus are emerging as an optimistic alternative due to their capacity to produce secondary metabolites with antagonistic activities against many fungal pathogens. This work aimed to develop ground-breaking research in the area of cultural and built heritage rehabilitation, by the development of natural and green safe biocides for biodegradation/biodeterioration treatment of Cultural Heritage. A complementary methodology, including antifungal tests and molecular approaches was used, in combination with microscopic and analytical techniques to detect, characterise and study the efficiency of the biological active compounds produced by Bacillus sp. strains. Flow cytometry allowed a comprehensive study of the physiological mechanism behind the bioactive compounds production in order to understand and improve the strategic approaches for process optimisation and scale up production. Moreover, according to the results of the toxicological tests, these compounds have proven to be a real environmental safe and innocuous alternative to the chemical biocides commonly used during the conservative interventions. Thus, they have shown a great potential for their future application in cultural and built heritage rehabilitation; Novos Biocidas para o Património Cultural Resumo: Vários microrganismos influenciados pelas condições ambientais são os principais responsáveis pela contaminação biológica do património cultural edificado. Na tentativa de mitigação destes agentes, compostos geralmente tóxicos têm sido os mais utilizados. Assim, é de enorme importância desenvolver ações de remediação dirigidas aos agentes efetivamente biodeteriogénicos, baseados em alternativas inócuas para o meio ambiente. As bactérias do género Bacillus surgem, como uma viável alternativa devido à capacidade de produzir metabolitos secundários com atividade antagonista, contra diversos fungos. Este trabalho teve como objetivo desenvolver uma investigação inovadora que possa vir a ser útil na área de reabilitação do património cultural edificado, através da produção de novos biocidas naturais e mais ecológicos. Utilizou-se uma abordagem metodológica, que incluiu testes antifúngicos e abordagens moleculares, combinadas com técnicas microscópicas e analíticas, de forma a detetar, caracterizar e estudar a eficiência de compostos biologicamente ativos produzidos por estripes de Bacillus sp.. Foram ainda utilizados os mecanismos fisiológicos por detrás da produção destes compostos, de forma a perceber e melhorar as abordagens estratégicas no processo de otimização da produção. Em testes toxicológicos, compostos produzidos por estirpes de Bacillus sp. selecionados, provaram ser uma… Advisors/Committee Members: Caldeira, Ana Teresa, Candeias, António, Teixeira, Dora.

Subjects/Keywords: Biodegradation/Biodeterioration; Bacillus sp.; Bioactive compounds; Lipopeptides; Iturin; Antifungal activity; Sporulation; Green biocides; Cultural heritage rehabilitation; Biodegradação/Biodeterioração; Bacillus sp.; Compostos bioativos; Lipopéptidos; Iturina; Atividade antifúngica; Esporulação; Biocidas ecológicos; Reabilitação do património histórico

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Silva, M. T. C. d. (2017). Novel biocides for cultural heritage. (Thesis). Universidade de Évora. Retrieved from https://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/21001

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Silva, Mara Teresa Caldeira da. “Novel biocides for cultural heritage.” 2017. Thesis, Universidade de Évora. Accessed April 06, 2020. https://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/21001.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Silva, Mara Teresa Caldeira da. “Novel biocides for cultural heritage.” 2017. Web. 06 Apr 2020.

Vancouver:

Silva MTCd. Novel biocides for cultural heritage. [Internet] [Thesis]. Universidade de Évora; 2017. [cited 2020 Apr 06]. Available from: https://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/21001.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Silva MTCd. Novel biocides for cultural heritage. [Thesis]. Universidade de Évora; 2017. Available from: https://www.rcaap.pt/detail.jsp?id=oai:dspace.uevora.pt:10174/21001

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Van Rooyen, Jaco. Biological control of postharvest disease in the perishable fruit industry by bacillus lipopeptides.

Degree: MEng, Process Engineering, 2018, Stellenbosch University

ENGLISH SUMMARY: The work presented in this study aimed to investigate the suitability of Bacillus spp. lipopeptides to be used as effective biocontrol agents that have the potential to replace chemically synthesised pesticides that are currently in use in post-harvest disease control. The screening criteria were based on the ability of different Bacillus species to produce antifungal lipopeptides which in turn could inhibit phytopathogens isolated from post-harvest grapes. The study further aimed to identify the lipopeptides responsible for any noted antifungal activity and investigate possible downstream isolation methods that could be included into process optimisation. With these goals in mind, the work presented here hopes to inform on the way forward for Future studies that are focused towards the controlled in vitro production of a customised cell-free biocontrol agent for post-harvest disease control. A phytopathogen culture bank was established from 79 crude isolates of fungi from post-harvest grapes supplied by the South African Table Grape industry. These isolates were purified into 59 pure cultures using 5 sequential rounds of subculturing on PDA, MEA and NA agar plates. Of these, 16 isolates were successfully sequenced using Sanger sequencing with ITS 4 and ITS 5 primers. Of the identified phytopathogens, 50% belonged to Penicillium spp., 33% to Botrytis spp. and the remaining 17% grouped as Aspergillus spp., Alternaria spp. and Lewia spp. These phytopathogens are responsible for noble rot, blue-green mould, bunch rot, black mould and leaf blight in the grape industry respectively. Four different strains of lipopeptide producing bacteria, Bacillus amyloliquefaciens DSM 23117, B. licheniformis DSM 13, B. subtilis ATCC 21332 and B. subtilis spizizini DSM 347 were obtained from culture collections and screened in triplicate in shake flasks over a seven day period using media from Kim et al (1997) with modifications. Bacillus amyloliquefaciens DSM 23117 was identified as the superior producer of lipopeptides. In addition to the significant amounts of lipopeptides produced by this strain, crude lipopeptides from B. amyloliquefaciens were shown to exhibit efficacy (either by causing death or static inhibition) towards all 9 isolated fungal phytopathogen strains tested in radial diffusion assays (RDA). The strains incorporated in RDA assays belonged to Botrytis, Penicillium, Alternaria, Aspergillus and Lewia genera. TLC separation in combination with antifungal efficacy assays further narrowed down the Iturin family, peaks 3, 4, 5, 8 and 9, as compounds that exerted significant antifungal activity. Thus indicating these compounds are important targets for isolation and incorporation into antifungal studies towards the development of cell-free biocontrol products for use in post-harvest applications and crop protection. Using different downstream methods for lipopeptide isolation and purification, salt precipitation was identified as a bulk isolation method while solvent extraction from isobutanol and… Advisors/Committee Members: Clarke, Kim Gail, Pott, Robert William M., Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering..

Subjects/Keywords: Bacillus amyloliquefaciens  – Biological control; Iturin; Postharvest diseases and pests  – Biological control; Grapes  – Diseases and pests  – Biological control; Lipopeptides as pest control agents; Biological pest control agents; Phytopathogenic fungi  – Biological control; UCTD

…families, from left to right, Surfactin, Iturin and Fengycin. Molecules reprinted with… …12 Chromatogram from B. amyloliquefaciens correlating peak name to peaks of Iturin… …Iturin A standards (bottom) ________________________________________________ 87 xiii… …and Iturin are both heptapeptides, 7 amino acid rings, with fatty acid chains of 12-17… …lipopeptide families, from left to right, Surfactin, Iturin and Fengycin. Molecules reprinted with… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Van Rooyen, J. (2018). Biological control of postharvest disease in the perishable fruit industry by bacillus lipopeptides. (Thesis). Stellenbosch University. Retrieved from http://hdl.handle.net/10019.1/103482

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Van Rooyen, Jaco. “Biological control of postharvest disease in the perishable fruit industry by bacillus lipopeptides.” 2018. Thesis, Stellenbosch University. Accessed April 06, 2020. http://hdl.handle.net/10019.1/103482.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Van Rooyen, Jaco. “Biological control of postharvest disease in the perishable fruit industry by bacillus lipopeptides.” 2018. Web. 06 Apr 2020.

Vancouver:

Van Rooyen J. Biological control of postharvest disease in the perishable fruit industry by bacillus lipopeptides. [Internet] [Thesis]. Stellenbosch University; 2018. [cited 2020 Apr 06]. Available from: http://hdl.handle.net/10019.1/103482.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Van Rooyen J. Biological control of postharvest disease in the perishable fruit industry by bacillus lipopeptides. [Thesis]. Stellenbosch University; 2018. Available from: http://hdl.handle.net/10019.1/103482

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.