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Michiel H. A. Michels Atze J. van der Goot Niels-Henrik Norsker René H. Wijffels 《Bioprocess and biosystems engineering》2010,33(8):921-927
The effect of shear stress on the viability of Chaetoceros muelleri was studied using a combination of a rheometer and dedicated shearing devices. Different levels of shear stress were applied
by varying the shear rates and the medium viscosities. It was possible to quantify the effect of shear stress over a wide
range, whilst preserving laminar flow conditions through the use of a thickening agent. The threshold value at which the viability
of algae was negatively influenced was between 1 and 1.3 Pa. Beyond the threshold value the viability decreased suddenly to
values between 52 and 66%. The effect of shear stress was almost time independent compared to normal microalgae cultivation
times. The main shear stress effect was obtained within 1 min, with a secondary effect of up to 8 min. 相似文献
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Interactions of multilamellar vesicles (MLV) of dilauroylphosphatidylcholine (DLPC) with the polyene antibiotics, amphotericin B (AmB) and nystatin (Ny), were followed by circular dichroism (CD). These interactions proceed with both antibiotics through a slow association with high [DLPC]/[antibiotic] stoichiometric molar ratios (> or = 130), at room temperature for which DLPC membranes are in a fluid state. Microscopic investigations of the spatial distributions of the antibiotic and the MLV in the mixtures revealed that MLV form clusters inside which the antibiotic is strongly concentrated and lipid superstructures appear. Concomitantly with the appearance of these superstructures a DLPC dichroic signal emerges. This observation indicates that the chiral properties of antibiotic oligomers can induce a chirality of the DLPC molecules which are bound to them. These results support the hypothesis of a recent molecular modeling of AmB oligomers which postulates that their chiral properties result from a chiral assemblage of antibiotic molecules (Millié et al., J. Phys. Chem. B, in press). 相似文献
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Colombo Mariana Michels Luana Roberta Teixeira Helder Ferreira Koester Letícia Scherer 《Phytochemistry Reviews》2022,21(3):783-808
Phytochemistry Reviews - The poor water solubility of flavonoids represents the greatest challenge to increasing the oral bioavailability of these compounds. Nevertheless, several potential... 相似文献
379.
Tarsal attachment devices of the southern green stink bug Nezara viridula (Heteroptera: Pentatomidae) 下载免费PDF全文
Manuela Rebora Jan Michels Gianandrea Salerno Lars Heepe Elena Gorb Stanislav Gorb 《Journal of morphology》2018,279(5):660-672
Based on analyses with cryo‐scanning and transmission electron microscopy, the present study reports on the morphology and ultrastructure of the attachment structures of the green stinkbug Nezara viridula L. (Heteroptera: Pentatomidae), a cosmopolitan pest of different crops in most areas of the world. In addition, the presence and distribution of large proportions of the elastic protein resilin in these structures was revealed by confocal laser scanning microscopy. The attachment structures of each leg comprise two sclerotised claws, a pair of smooth flexible pulvilli and a hairy adhesive pad located at the ventral side of the basitarsus. No sexual dimorphism is evident. Contact areas of resting individuals on a smooth surface show that N. viridula creates contact to the substrate with the ventral surface of (a) the distal portions of the pulvilli, (b) the setae of the hairy adhesive pad, (c) the two paraempodia representing mechanosensory setae, and (d) the tips of the claws. Each pulvillus is a sac‐like structure formed by complex cuticular layers that vary in their structure and resilin content. The dorsal side consists of sclerotised chitinous material, while the ventral cuticle consists mainly of resilin and shows a very thin epicuticle and a thick exocuticle. The setae of the hairy adhesive pad are pointed and socketed. They exhibit a pronounced longitudinal gradient in the material composition, with large proportions of resilin being present in the setal tips. In most of these setae, especially in those of the distal‐most part of the pad, also a transverse gradient in the material composition is visible. 相似文献
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Phase V of the single-breath washout test 总被引:1,自引:0,他引:1