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  • 1
    In: Materials, MDPI AG, Vol. 15, No. 2 ( 2022-01-09), p. 481-
    Abstract: In the current study, a green method for the preparation of silver nanoparticles (AgNPs) is presented as an alternative to conventional chemical and physical approaches. A biomass of Trichoderma reesei (T. reesei) fungus was used as a green and renewable source of reductase enzymes and metabolites, which are capable of transforming Ag+ ions into AgNPs with a small size (mainly 2–6 nm) and narrow size distribution (2–25 nm). Moreover, extracellular biosynthesis was carried out with a cell-free water extract (CFE) of T. reesei, which allows for facile monitoring of the bioreduction process using UV–Vis spectroscopy and investigation of the effect of experimental conditions on the transformation of Ag+ ions into AgNPs, as well as the simple isolation of as-prepared AgNPs for the study of their size, morphology and antibacterial properties. In continuation to our previous results about the influence of media on T. reesei cultivation, the amount of biomass used for CFE preparation and the concentration of Ag+ ion solution, herein, we present the impact of temperature (4, 20, 30 and 40 °C), agitation and time duration on the biosynthesis of AgNPs and their properties. A high stability of AgNPs in aqueous colloids was observed and attributed to the capping effect of the biomolecules as shown by the zeta potential (−49.0/−51.4 mV) and confirmed by the hydrodynamic size of 190.8/116.8 nm of AgNPs.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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  • 2
    Online Resource
    Online Resource
    National Society of Ecological Engineering and Environment Protection ; 2021
    In:  Ecological Engineering and Environment Protection Vol. 2021, No. 3/2021 ( 2021-12-20), p. 57-66
    In: Ecological Engineering and Environment Protection, National Society of Ecological Engineering and Environment Protection, Vol. 2021, No. 3/2021 ( 2021-12-20), p. 57-66
    Abstract: The purpose of this short review article is to present the results of the influence of the ionizing X-ray pulses of plasma focus on living organisms, by performing experiments in vivo and analyzing changes in some vital characteristics of the objects, such as survival ability, efficiency of photosynthesis of unicellular organisms at moderate doses (up to 65 mSv); efficiency of enzyme production, change in protein content and change in fungi mass in the radiation dose range 7 mSv ÷ 45 Sv; changes in mammalian blood characteristics and appearance of signs of anemia due to the significant dose load.
    Type of Medium: Online Resource
    URL: Issue
    URL: Issue
    Language: English
    Publisher: National Society of Ecological Engineering and Environment Protection
    Publication Date: 2021
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  • 3
    Online Resource
    Online Resource
    Informa UK Limited ; 2014
    In:  Biotechnology & Biotechnological Equipment Vol. 28, No. 5 ( 2014-09-03), p. 850-854
    In: Biotechnology & Biotechnological Equipment, Informa UK Limited, Vol. 28, No. 5 ( 2014-09-03), p. 850-854
    Type of Medium: Online Resource
    ISSN: 1310-2818 , 1314-3530
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 2014
    detail.hit.zdb_id: 2400627-0
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  • 4
    In: Journal of Physics: Conference Series, IOP Publishing, Vol. 1598, No. 1 ( 2020-07-01), p. 012003-
    Abstract: In order to increase the biosynthetic capacity of the Trichoderma reesei-M7 strain – a notorious cellulase enzyme producer – the experimental biological object to be studied was exposed to the impact of the highly energetic X-ray pulses, produced by the dense plasma focus device (DPF). The X-ray pulses thus produced can have exceptionally high density of the flow of X-photons. The pulsed mode of irradiation fundamentally differs from the continuous when considering its effect on biological objects – they can rapidly absorb great amounts of radiation in a glimpse, leading to a qualitatively different interaction with their matter. In the experiments done the survivability was determined, as well as the vegetative biomass, four types of cellulase activity and the quantity of total protein after the treatment of the spores suspension (2.105 CFU/ml) of Trichoderma reesei M7 with this pulsed X-radiation. The absorbed doses were in the range of 7 to 45000 mSv. It was noticed that the survivability of the strain, if compared with the control samples, drops, reaching 57% of the initial value (of the untreated spores) for the sample with 45010 mSv of absorbed dose. From the data presented below it can be concluded that three of the samples with high absorbed doses, namely with 11754, 19439 and 42917 mSv, demonstrated increases their cellulase activities. In the case of 42917 mSv the increment of the endoglucanase activity, compared to the control, reaches 41,1%, FPA rises with 30,3%, and the β-glucosidase activity nearly doubles – and increase of 92,7%.
    Type of Medium: Online Resource
    ISSN: 1742-6588 , 1742-6596
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 2166409-2
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  • 5
    In: Materials, MDPI AG, Vol. 14, No. 15 ( 2021-07-26), p. 4153-
    Abstract: To broaden the application of silver nanoparticles (AgNPs), which are well-known antibacterial agents, they are supported on different substrates to prevent aggregation, increase their surface area and antibacterial efficiency, and to be separated from the system more effectively at the end of treatment. To produce nanocomposites that consist of silver nanoparticles on natural and modified zeolites, silver ions (Ag+) were loaded onto zeolite (natural, Na-modified, H-modified) and then thermally reduced to AgNPs. The effect of the exchangeable cations in zeolite on Ag+ uptake, AgNPs formation, size and morphology was investigated by the TEM, SEM, EDX, XPS, UV-vis, XRD and BET methods. The silver amount in the nanocomposites decreased in the following order Na-modified zeolite 〉 natural zeolite 〉 H-modified zeolite. Microscopic techniques showed formation of AgNPs of 1–14 nm on natural and Na-modified zeolite, while the diameter of metal particles on H-modified zeolite was 12–42 nm. Diffuse reflectance UV-vis and XPS methods revealed the presence of both silver ions and AgNPs in the materials indicating that partial reduction of Ag+ ions took place upon heating at 400 °C in air. Additionally, antibacterial properties of the nanocomposites were tested against Escherichia coli, and it was found that Ag–containing composites originating from the Na-modified zeolite demonstrated the highest activity.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2487261-1
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