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- Xie, Zhe, et al.
(författare)
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Combined effect of salinity and hypoxia on digestive enzymes and intestinal microbiota in the oyster Crassostrea hongkongensis
- 2023
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Ingår i: Environmental Pollution. - 0269-7491 .- 1873-6424. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Anthropologic activities caused frequent eutrophication in coastal and estuarine waters, resulting in diel-cycling hypoxia. Given global climate change, extreme weather events often occur, thus salinity fluctuation frequently breaks out in these waters. This study aimed to evaluate the combined effects of salinity and hypoxia on intestinal microbiota and digestive enzymes of Crassostrea hongkongensis. Specifically, we sequenced 16 S rRNA of intestinal microbiota and measured the digestive enzymes trypsin (TRS), lipase (LPS) and amylase (AMY) in oysters exposed for 28 days to three salinities (10, 25 and 35) and two dissolved oxygen conditions, normoxia (6 mg/L) and hypoxia (6 mg/L for 12 h, 2 mg/L for 12 h). Oysters in normoxia and salinity of 25 were treated as control. After 28-day exposure, for microbial components, Fusobacteriota, Firmicutes, Bacteroidota, Proteobacteria and Actinobacteriota comprised the majority for all experimental groups. Compared with the control group, the diversity and structure of intestinal microbiota tended to change in all treated groups. The species richness in C. hongkongensis intestine also changed. It was the most significant that high salinity increased Proteobacteria proportion while low salinity and hypoxia increased Fusobacteriota but decreased Proteobacteria, respectively. Additionally, Actinobacteriota was sensitive and changed under environmental stressor (P < 0.01). The prediction results on intestinal microbiota showed that, all functions of oysters were up-regulated to distinct degrees under low/high salinity with hypoxia. According to the KEGG prediction, cellular processes were more active and energy metabolism upregulated, indicating the adaptation of C. hongkongensis to environmental change. Periodical hypoxia and low/high salinity had complex effect on the digestive enzymes, in which the activity of TRS and LPS decreased while AMY increased. High/low salinity and periodical hypoxia can change the secretion of digestive enzymes and influence intestinal microbial diversity and species richness of C. hongkongensis, deducing the chronic adverse effects on the digestive physiology in long-term exposure.
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| 2. |
- Wang, Tianxiao, et al.
(författare)
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Fluoride releasing in polymerblends of poly(ethylene oxide) and poly(methyl methacrylate)
- 2024
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Ingår i: Frontiers in Chemistry. - : Frontiers Media S.A.. - 2296-2646. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Polymethyl methacrylate is a polymer commonly used in clinicaldentistry, including denture bases, occlusal splints and orthodontic retainers.Methods: To augment the polymethyl methacrylate-based dental appliances incounteracting dental caries, we designed a polymer blend film composed ofpolymethyl methacrylate and polyethylene oxide by solution casting and addedsodium fluoride.Results: Polyethylene oxide facilitated the dispersion of sodium fluoride,decreased the surface average roughness, and positively influenced thehydrophilicity of the films. The blend film made of polymethyl methacrylate,polyethylene oxide and NaF with a mass ratio of 10: 1: 0.3 showed sustainedrelease of fluoride ions and acceptable cytotoxicity. Antibacterial activity of all thefilms to Streptococcus mutans was negligible.Discussion: This study demonstrated that the polymer blends of polyethyleneoxide and polymethyl methacrylate could realize the relatively steady release offluoride ions with high biocompatibility. This strategy has promising potential toendow dental appliances with anti-cariogenicity.
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