2,347 research outputs found

    Cyanomatrix and Cyanofilm

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    Cyanobacteria are diverse in their habitats, structure, and metabolism that can grow as unicellular or long filaments and secreting high molecular mass polymers (extracellular polymer substances, EPS), which can either be released into the surrounding environment or remain attached to the cell surface. Four different cyanobacterial environmental samples (soil crust, microbial mats, pond water and marine bloom) were studied to compare between the cyanobacteria species that grow and form cyanomatrix and cyanofilms in those environmental habitats using light and scanning electron microscope (SEM). Diatoms were also detected with cyanobacteria at microbial mats and pond water samples. All samples had variable concentrations and compositions of extracellular matrix and biofilm. Microscopic observation and analyses also revealed complex network of filamentous cyanobacteria and extracellular polymer secretions, which binds and traps particles of soil and minerals

    Hypolithic cyanobacteria colonization of quartz at South Desert

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    Hypolithic microbial communities (found underneath rocks) were encountered in the southern desert of Qatar where quartz rocks are ubiquitous and are a substrate for hypoliths. These hypoliths thrive where extreme temperature, moisture stress and high light intensity limit the occurrence of higher plants and animal life. A small-scale ecological survey indicated that 80% of the quartz rocks in the area were colonized by green hypolithic microbial communities dominated by colonization of cyanobacteria. Using light and electron microscopic analyses; the cyanobacterial community structure of hypoliths was shown to be dominated by cyanobacteria affiliated to the genera Chroococcidiopsis, Aphanothece, Pleurocapsa, Oscillatoria, Lyngbya, Leptolyngbya, Phormidium and Scytonema).Scopu

    Ecophysiology of Wild Plants and Conservation Perspectives in the State of Qatar

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    © 2013 Yasseen and Al-Thani, licensee InTech. This is an open access chapter distributed under the term

    Diversity of Bacillus thuringiensis Strains From Qatar as Shown by Crystal Morphology, d-Endotoxins and Cry Gene Content

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    Bacillus thuringiensis (Bt) based insecticidal formulations have been recognized as one of the most successful, environmentally safe and sustainable method of controlling insect pests. Research teams worldwide are in search of Bt diversity giving more choices of bio-insecticides and alternatives to address insect resistance. In fact, there are many unexplored ecologies that could harbor novel Bt strains. This study is the first initiative to explore Bt strain diversity in Qatar. A collection of 700 Bt isolates was constructed. Scanning electron microscopy of Bt crystals showed different crystal forms, with a high abundance of spherical crystals compared to the bipyramidal ones. Among the spherical crystals, four differentmorphologies were observed. The d-endotoxin content of parasporal crystals fromeach Bt isolate revealed that there are 16 different protein profiles among the isolates of the collection. On the other hand, plasmid pattern analysis showed seven different plasmid profiles. Their insecticidal activity was predicted by exploring the d-endotoxin coding genes and conducting qualitative insecticidal bioassays. 19 smooth spherical crystal producing isolates have been identified that could be possible candidates for endotoxin production targeting Dipteran insects. Another group of 259 isolates producing bipyramidal and cuboidal crystals could target Lepidopteran and Coleopteran insects. The remaining 422 isolates have novel profiles. In conclusion, Qatari soil ecology provides a good collection and diversity of Bt isolates. In addition to strains harboring genes encoding common endotoxins, the majority are different and very promising for the search of novel insecticidal endotoxins.QNR

    Fungal food spoilage of supermarkets' displayed fruits

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    Background and Aim: Post-harvest fungal infection of fruits and vegetables is mainly caused by fungal pathogens that can be harmful to both human and animals as they produce mycotoxins, post-harvest diseases in fruits and vegetables are a serious problem that results in the loss of a large percentage of crops reaching 50% in some fruits. This study aims at screening the post-purchasing shelf-life of four highly consumed fruits and vegetables and at identifying the fungal strains behind their spoilage in Qatar. Materials and Methods: Fruits and vegetables were collected from the market to study their post-purchasing shelf-life and to identify the fungal types involved in samples rotting. Factors that affect samples' shelf-life were also analyzed. Results: A total of 73 fungal isolates were isolated and identified, with the highest percentage of Penicillium (21.9%) followed by Rhizopus (17.8%). Interestingly, many mycotoxins producing and diseases inducing fungi were identified in this study; this includes Rhizopus, Aspergillus, Penicillium, Alternaria, Fusarium, Cladosporium, Botrytis, Geotrichum, and Colletotrichum. Statistical analysis shows that different fruits have significantly different shelf-life and different predispositions for spoilage. In many cases, a strong relationship was shown between the fungal types isolated and the country of origin of the fruit. Finally, the price of the commodity did not have a significant effect on its contamination level nor did the market from which the sample was purchased. This indicates that the fruit displaying methods in Qatar do not affect their contamination level. Conclusion: The study is among the first reports about fungal types involved in fruits and vegetables rotting in Qatar and it highlights the strong link between spoiling fungi and their country of origin.The authors wish to thank Dr. Mohammed Abu-Dieyeh at the Biological and Environmental Sciences Department at Qatar University for his assistance in identifying some of the isolated species and Mr. Ahmad Hawi for his valuable input in the statistical analysis. This study was partially funded by Biological and Environmental Science Department of Qatar University.Scopu

    Patulin and patulin producing Penicillium spp. occurrence in apples and apple-based products including baby food

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    Introduction: Patulin has raised the international attention because of its health risk. In fact, it has mutagenic, neurotoxic, immunotoxic, genotoxic and gastrointestinal effects in animals. In the present work, patulin and patulin-producing Penicillium spp. in apple and apple-based products marketed in Qatar were analysed. Methodology: Sampling was carried out using apple fruits and apple-based products. Fungi were isolated from undamaged apples, apple juice and baby apple food. DNA extraction was carried out with DNeasy Plant Mini Kit (QIAGEN, Valencia, USA). The molecular identification of fungal isolates was carried out using ITS1-ITS4 PCR. PCR products were sequenced and blasted. Patulin was extracted and analyzed by LC/MS/MS, then quantified using Agilent 1290UHPLC coupled to 6460 triple quadruple mass spectrometer. Results: Forty-five samples of undamaged fresh apple fruits, apple juice and apple-based baby food products sold in different markets in Qatar were surveyed for both fungal and patulin contamination using Liquid Chromatography Tandem Mass Spectrometery (LC/MS/MS). Twenty-five Penicillium spp. isolates were selected, including 23 P. expansum and one isolate each of P. brevicompactum and P. commune. All the tested Penicillium spp. isolates produced patulin in vitro (from 40 to 100 μg/g on Malt Yeast Extract agar medium). Patulin was detected in 100% of apple juice samples at levels ranging from 5.27 to 82.21 μg/kg. Only 5 samples contained patulin levels higher than European Union recommended limit (50 μg/kg). The average patulin contamination was 30.67 μg/kg and 10.92 μg/kg in baby apple juice and in baby apple compote, respectively.This publication was made possible by NPRP grant # NPRP 4-259-2-083 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors

    Detection of multimycotoxins in camel feed and milk samples and their comparison with the levels in cow milk

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    Camel milk has been considered as an important source of nutrients and is commercialized in many countries of the world including the Middle East. This study aimed to investigate the presence of mycotoxins in camel feed and milk samples in comparison with the cow milk. Fumonisins (FUM), ochratoxin A (OTA), and zearalenone (ZEN) were detected in 14%, 39%, and 39% of the tested camel feed samples, respectively. Among the tested camel feed samples, 8.3% and 5.6% were co-contaminated with OTA+FUM and FUM+ZEN, respectively. In the case of milk samples, 46.15% of camel and 63.63% of cow were found contaminated with aflatoxin M1 (AFM1). In total, 16.2% and 8.1% of the milk samples were simultaneously contaminated with two and three mycotoxins, respectively. Although the levels of individual mycotoxins in the camel feed and milk samples were within the European Union (EU) permissible limits, their co-occurrence may pose severe risk to human and animal health due to possible additive and/or synergistic toxicities.This project was made possible by NPRP grant #8-392-4-003 from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors. The publication of this article was supported by the Qatar National Library member of the Qatar Foundation

    Bacillus thuringiensis strain QBT220 pBtoxis plasmid structural instability enhances δ-endotoxins synthesis and bioinsecticidal activity

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    Bacillus thuringiensis subsp. israelensis (Bti) spherical parasporal crystal contains several insecticidal proteins used as environmentally safe alternative to toxic chemical pesticides. The exploration of a Bti strain isolated from Qatar QBT220 genes encoding the δ-endotoxins responsible of the insecticidal activities revealed the alteration of a 14-kb DNA region including the δ-endotoxins cry10A and cyt1C genes of pBtoxis plasmid. The presence of all the insecticidal genes except cry10A and cyt1C was explained by a structural instability of the plasmid pBtoxis. However, when compared with the Bti reference strains H14 and QBT217 that carry all δ-endotoxins coding genes, it was found that QBT220, has a significantly higher insecticidal activity against the dipteran insect Aedes aegypti larvae despite of the plasmid pBtoxis structural instability due to the alteration of cry10A and cyt1C genes. In addition, QBT220 showed the highest δ-endotoxin synthesis per spore, compared with that of the wildtype strains. These findings confirm that the altered genes cry10A and cyt1C are not mandatory for Bti insecticidal activities and on the other hand show a possible inhibitory effect played by the 2 proteins Cry10A and Cyt1C on the insecticidal activities of the other insecticidal proteins. In addition, the QBT220 increased δ-endotoxins synthesis per cell, makes this strain a good candidate for possible applications in the industrial production of bioinsecticides

    Anti-microbial Activity Of Graphene Oxide Against Bacteria And Fungi

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    Graphene Oxide (GO) is a promising material for various applications. The team prepared GO from graphite and studied the interaction with different microorganisms. Anti-microbial properties were detected for the prepared GO. Anti-microbial activities of GO was tested against one eukaryotic fungi (Candida albicans) two prokaryotic bacteria Gram-negative bacilli (Escherichia coli ATCC 41570 and Pseudomonas aeruginosa ATCC 25619) and two prokaryotic bacteria Gram-positive cocci (Streptococcus feacalis 19433 and Staphylococcus aureus ATCC 11632). Spectrophotometer was used to measure the growth as an indirect method, viable cell counting was used as direct method. Readings were taken at successive incubated times. Results revealed that GO exhibited stronger antibacterial and anti-fungal activity against the used bacteria and fungi species. Acknowledgements: This research was made possible by NPRP grant (NPRP5-039-2-014) from the Qatar National Research Fund (a member of Qatar Foundation). The statement made herein are solely the responsibility of the author.qscienc

    Total Cost of Ownership Driven Methodology for Predictive Maintenance Implementation in Industrial Plants

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    Part 4: Product and Asset Life Cycle Management in Smart Factories of Industry 4.0International audienceThis paper proposes a methodology to drive from a strategic point of view the implementation of a predictive maintenance policy within an industrial plant. The methodology integrates the evaluation of system performances, used to identify the critical components, with simulation and cost analysis. The goal is to evaluate predictive maintenance implementation scenarios based on alternative condition monitoring (CM) solutions, under the lenses of Total Cost of Ownership (TCO). This allows guiding the decision on where in the industrial system to install diagnostic solutions for monitoring of asset health, by keeping a systemic and life cycle-oriented perspective. Technical systemic performances are evaluated through Monte Carlo simulation based on the Reliability Block Diagram (RBD) model of the system. To validate the methodology, an application case study focused on a production line of a relevant Italian company in the food sector is presented
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