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Molecular characterization of mycotoxin producing moulds from grains and legumes and their susceptibility to plant extracts
Get PDFDoctoral thesis on mycotoxin producing moulds from grains and legumes. It also contains pictures and tablesMolecular characterization of mycotoxin producing moulds from grains and legumes and their susceptibility to plant extracts was studied. Grains and legumes were stored for a period of two and four months. They were analysed for the presence of moulds and mycotoxin producing moulds. They were also analysed for the production of different mycotoxins. Sabouraud dextrose agar, Sabouraud dextrose broth, potato dextrose agar and malt extract agar were used in this study. The methods of isolation used were direct physical examination and direct plate count method. Moulds were identified based on their colony morphology, cultural characteristics and molecular characterization. Mycotoxin analysis was done using Liquid chromatography tandem mass spectrometry. Antifungal susceptibility test was done using the Clinical Laboratory and Standards Institute approved methods for testing of moulds using disk diffusion method. The following four oxoid antifungal agents were used: Amphotericin B, fluconazole, ketoconazole and voriconazole. The following medicinal plants: Ocimum gratissimum (scent leaves), Vemonia amygdalina (bitter leaves), Gongronema latifolium (utazi leaves) and Piper guineense (uziza leaves) were assessed for their phytochemical properties and antifungal susceptibility profile against various moulds. The organic solvents used for antifungal susceptibility profile were methanol and hot water. One way analysis of variance, Duncan tests and descriptive statistics were used for statistical analysis. The moulds isolated and identified culturally were Aspergillus sp. Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus, Penicillium chrysogenum, Fusarium sp, Rhizopus stolonifer, Rhizopus nigricans and Mucor sp. while those identified molecularly were Aspergillus flavus, Aspergillus tamarii, Aspergillus niger, Aspergillus brunneoviolaceus, and Penicillium chrysogenum. The genus Aspergillus was the most prevalent mould. Groundnut had the highest number of isolates followed by maize, beans, rice while wheat had the least number of isolates. The numbers of colony forming units were more in Potato dextrose agar, Sabouraud dextrose agar and least on malt extract agar. Potato dextrose agar recovered the highest number of isolates from both unstored and stored samples followed by sabouraud dextrose agar then malt extract agar. The following mycotoxins were detected Aflatoxin B1, Aflatoxin B2, Aflatoxin G1, Aflatoxin G2, Ochratoxin A, Citrinin, Dihydrocitrinone, Fumonisin B1, Fumonisin B2, Fumonisin B3, Fumonisin B4, Zearalenone, Deoxynivalenol and Nivalenol. Aflatoxin was the most frequent mycotoxin detected. Rice (1286.3 ± 29.689 µg/kg) had the highest rate of recovery of mycotoxins followed by wheat (1166.8 ± 0.901 µg/kg) and groundnuts (1142.9 ± 10.488 µg/kg) while maize (1111.6 ± 9.810 µg/kg) had the least concentration of mycotoxins. Ketoconazole (39 ±1.000 mm) had the highest minimum inhibitory concentration among different anti-fungal agents, followed by voriconazole (36 ± 2.000 mm), Amphotericin B (30 ±2.000 mm) and then Fluconazole (21 ± 12.124 mm). Susceptibility profile using only tetrazolium gave no zone of inhibition. Antifungal agents alone gave a better zone of inhibition than the combination of antifungal agents with tetrazolium. The medicinal plants such as scent leaves, bitter leaves, uziza leaves and utazi leaves analysed contained the following phytochemicals tannin, alkaloid, steroid, saponin and flavonoid. Percentage growth inhibition of moulds by methanol and hot water xiii extract of scent leaf gave the highest inhibition followed by bitter leaf, utazi and uziza gave the least growth inhibition. Methanol extract gave a better inhibition than hot water extract at 100 mg/ml and 50 mg/ml. One-way analysis of variance and Duncan tests showed that there was a significant difference (P < 0.05) between the isolates found in stored and unstored grains and legume. There was also a significant difference (P < 0.05) between the antifungal agents and media used. Potato dextrose agar should be used frequently since it gave the highest rate of mould recovery. Ketoconazole remains the best drug of choice among other antifungal agents against moulds. Medicinal plants like scent leaves, bitter leaves, utazi leaves and uziza leaves gave varying levels of growth inhibition against various isolates and should be used both at home and clinical settings. The grains and legumes studied were contaminated with various species of moulds and contained many mycotoxins of public health importance
Molecular characterization of mycotoxin producing moulds from grains and legumes and their susceptibility to plant extracts
Get PDFDoctoral thesis on mycotoxin producing moulds from grains and legumesMolecular characterization of mycotoxin producing moulds from grains and legumes and their susceptibility to plant extracts was studied. Grains and legumes were stored for a period of two and four months. They were analysed for the presence of moulds and mycotoxin producing moulds. They were also analysed for the production of different mycotoxins. Sabouraud dextrose agar, Sabouraud dextrose broth, potato dextrose agar and malt extract
agar were used in this study. The methods of isolation used were direct physical examination and direct plate count method. Moulds were identified based on their colony morphology, cultural characteristics and molecular characterization. Mycotoxin analysis was done using Liquid chromatography tandem mass spectrometry. Antifungal susceptibility test was done using the Clinical Laboratory and Standards Institute approved methods for testing of moulds using disk diffusion method. The following four oxoid antifungal agents were used: Amphotericin B, fluconazole, ketoconazole and voriconazole. The following medicinal plants: Ocimum gratissimum (scent leaves), Vemonia amygdalina (bitter leaves), Gongronema latifolium (utazi leaves) and Piper guineense (uziza leaves) were assessed for their phytochemical properties and antifungal susceptibility profile against various moulds. The organic solvents used for antifungal susceptibility profile were methanol and hot water. One way analysis of variance, Duncan tests and descriptive statistics were used for statistical analysis. The moulds isolated and identified culturally were Aspergillus sp. Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus, Penicillium chrysogenum, Fusarium sp, Rhizopus stolonifer, Rhizopus nigricans and Mucor sp. while those identified molecularly were Aspergillus flavus, Aspergillus tamarii, Aspergillus niger, Aspergillus brunneoviolaceus, and Penicillium chrysogenum. The genus Aspergillus was the most prevalent mould. Groundnut had the highest number of isolates followed by maize, beans, rice while wheat had the least number of isolates. The numbers of colony forming units were more in Potato dextrose agar, Sabouraud dextrose agar and least on malt extract agar. Potato dextrose agar recovered the highest number of isolates from both unstored and stored samples followed by sabouraud dextrose agar then malt extract agar. The following mycotoxins were detected Aflatoxin B1, Aflatoxin B2, Aflatoxin G1, Aflatoxin G2, Ochratoxin A, Citrinin, Dihydrocitrinone, Fumonisin B1, Fumonisin B2, Fumonisin B3, Fumonisin B4, Zearalenone, Deoxynivalenol and Nivalenol. Aflatoxin was the most frequent mycotoxin detected. Rice (1286.3 ± 29.689 µg/kg) had the highest rate of recovery of mycotoxins followed by wheat (1166.8 ± 0.901 µg/kg) and groundnuts (1142.9 ± 10.488 µg/kg) while maize (1111.6 ± 9.810 µg/kg) had the least concentration of mycotoxins. Ketoconazole (39 ±1.000 mm) had the highest minimum inhibitory concentration among different anti-fungal agents, followed by voriconazole (36 ± 2.000 mm), Amphotericin B (30 ±2.000 mm) and then Fluconazole (21 ± 12.124 mm). Susceptibility profile using only tetrazolium gave no zone of inhibition. Antifungal agents alone gave a better zone of inhibition than the combination of antifungal agents with tetrazolium. The medicinal plants such as scent leaves, bitter leaves, uziza leaves and utazi leaves analysed contained the following phytochemicals tannin, alkaloid, steroid, saponin and flavonoid. Percentage growth inhibition of moulds by methanol and hot water xiiiextract of scent leaf gave the highest inhibition followed by bitter leaf, utazi and uziza gave the least growth inhibition. Methanol extract gave a better inhibition than hot water extract at 100 mg/ml and 50 mg/ml. One-way analysis of variance and Duncan tests showed that there was a significant difference (P < 0.05) between the isolates found in stored and unstored grains and legume. There was also a significant difference (P < 0.05) between the antifungal agents and media used. Potato dextrose agar should be used frequently since it gave the highest rate of mould recovery. Ketoconazole remains the best drug of choice among other antifungal agents against moulds. Medicinal plants like scent leaves, bitter leaves, utazi leaves and uziza leaves gave varying levels of growth inhibition against various isolates and should be used both at home and clinical settings. The grains and legumes studied were
contaminated with various species of moulds and contained many mycotoxins of public health importance
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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