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191.
Katarzyna Paszkowska-Szczur Rodney J. Scott Bohdan Górski Cezary Cybulski Grzegorz Kurzawski Dagmara Dymerska Satish Gupta Thierry van de Wetering Bartłomiej Masojć Aniruddh Kashyap Paulina Gapska Tomasz Gromowski Józef Kładny Jan Lubiński Tadeusz Dębniak 《Molecular biology reports》2015,42(3):755-764
192.
We studied the influence of habitat and increased mineral phosphorus and nitrogen loading on the extracellular activity of
five selected hydrolases and pH in the trap fluid of the aquatic carnivorous plants, Utricularia vulgaris, U. australis, and U. foliosa (Lentibulariaceae). Enzyme activities in the trap fluid were determined using fluorometry. Phosphatase exhibited the highest
activities in the traps of the European species as well as field-grown tropical U. foliosa. Trap enzyme production appeared to be uninfluenced by elevated dissolved mineral N or P concentrations both in the trap
and ambient environment and thus, it seems to be constitutive. Enzyme activity in the trap fluid was determined by species
and environmental conditions and varied significantly among sites within a single species. Trap fluid pH was between 4.2–5.1
in U. vulgaris and U. australis but between 5.7–7.3 in U. foliosa and seems to be regulated by the traps. 相似文献
193.
The effect of UV-irradiation on four different types of native starch (corn, waxy corn, wheat and potato) have been investigated. Although the changes in the chemical structure of starch specimens were small, indicating good photostability, the samples lost adsorbed water and their crystallinity degree decreased after irradiation. Moreover, a drop in average molecular weight occurred in samples (with the exception of potato starch) as a result of main chain scission. The variations in the properties of investigated specimens of various origin were related to the differences in their structure and macromolecular arrangement. The lowest photostability among the four starches was exhibited by potato starch. 相似文献
194.
Carina Conceicao Nazia Thakur Stacey Human James T. Kelly Leanne Logan Dagmara Bialy Sushant Bhat Phoebe Stevenson-Leggett Adrian K. Zagrajek Philippa Hollinghurst Michal Varga Christina Tsirigoti Matthew Tully Chris Chiu Katy Moffat Adrian Paul Silesian John A. Hammond Helena J. Maier Erica Bickerton Holly Shelton Isabelle Dietrich Stephen C. Graham Dalan Bailey 《PLoS biology》2020,18(12)
SARS Coronavirus 2 (SARS-CoV-2) emerged in late 2019, leading to the Coronavirus Disease 2019 (COVID-19) pandemic that continues to cause significant global mortality in human populations. Given its sequence similarity to SARS-CoV, as well as related coronaviruses circulating in bats, SARS-CoV-2 is thought to have originated in Chiroptera species in China. However, whether the virus spread directly to humans or through an intermediate host is currently unclear, as is the potential for this virus to infect companion animals, livestock, and wildlife that could act as viral reservoirs. Using a combination of surrogate entry assays and live virus, we demonstrate that, in addition to human angiotensin-converting enzyme 2 (ACE2), the Spike glycoprotein of SARS-CoV-2 has a broad host tropism for mammalian ACE2 receptors, despite divergence in the amino acids at the Spike receptor binding site on these proteins. Of the 22 different hosts we investigated, ACE2 proteins from dog, cat, and cattle were the most permissive to SARS-CoV-2, while bat and bird ACE2 proteins were the least efficiently used receptors. The absence of a significant tropism for any of the 3 genetically distinct bat ACE2 proteins we examined indicates that SARS-CoV-2 receptor usage likely shifted during zoonotic transmission from bats into people, possibly in an intermediate reservoir. Comparison of SARS-CoV-2 receptor usage to the related coronaviruses SARS-CoV and RaTG13 identified distinct tropisms, with the 2 human viruses being more closely aligned. Finally, using bioinformatics, structural data, and targeted mutagenesis, we identified amino acid residues within the Spike–ACE2 interface, which may have played a pivotal role in the emergence of SARS-CoV-2 in humans. The apparently broad tropism of SARS-CoV-2 at the point of viral entry confirms the potential risk of infection to a wide range of companion animals, livestock, and wildlife.A study using a combination of surrogate entry assays and live virus suggests that SARS-CoV-2 may have a broad host-range, revealing that the virus''s spike protein can use a broad range of host ACE2 receptors to enter cells and that the sequence of this protein might have changed during the zoonotic jump into humans. 相似文献
195.