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排序方式: 共有569条查询结果,搜索用时 15 毫秒
91.
Rosana Alves Sandra Mota Sónia Silva Célia F. Rodrigues Alistair J. P. Brown Mariana Henriques 《Biofouling》2017,33(10):943-954
Candida albicans has the ability to adapt to different host niches, often glucose-limited but rich in alternative carbon sources. In these glucose-poor microenvironments, this pathogen expresses JEN1 and JEN2 genes, encoding carboxylate transporters, which are important in the early stages of infection. This work investigated how host microenvironments, in particular acidic containing lactic acid, affect C. albicans biofilm formation and antifungal drug resistance. Multiple components of the extracellular matrix were also analysed, including their impact on antifungal drug resistance, and the involvement of both Jen1 and Jen2 in this process. The results show that growth on lactate affects biofilm formation, morphology and susceptibility to fluconazole and that both Jen1 and Jen2 might play a role in these processes. These results support the view that the adaptation of Candida cells to the carbon source present in the host niches affects their pathogenicity. 相似文献
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Daniel Prá Silvia Isabel Rech Franke Raquel Giulian Maria Lúcia Yoneama Johnny Ferraz Dias Bernardo Erdtmann João Antonio Pêgas Henriques 《Biometals》2008,21(3):289-297
The toxicity of trace metals is still incompletely understood. We have previously shown that a single oral dose of iron or copper induces genotoxic effects in mice in vivo, as detected by single cell gel electrophoresis (comet assay). Here, we report the effect of these metals on subchronic exposure. Mice were gavaged for six consecutive days with either water, 33.2 mg/kg iron, or 8.5 mg/kg copper. On the 7th day, the neutral and alkaline comet assays in whole blood and the bone marrow micronucleus (MN) test were used as genotoxicity and mutagenicity endpoints, respectively. Particle induced X-ray emission was used to determine liver levels of the metals. Females showed a slightly lower DNA damage background, but there was no significant difference between genders for any endpoint. Iron and copper were genotoxic and mutagenic. While copper was more genotoxic in the neutral version, iron was more genotoxic in the alkaline version of the comet assay. Copper induced the highest mutagenicity as evaluated by the MN test. Iron was not mutagenic to male mice. Iron is thought to induce more oxidative lesions than copper, which are primarily detected in the alkaline comet assay. Treatment with iron, but not with copper, induced a significant increase in the hepatic level of the respective metal, reflecting different excretion strategies. 相似文献
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Activation of the late prespore-specific RNA polymerase sigma factor sigma(G) during Bacillus subtilis sporulation coincides with completion of the engulfment process, when the prespore becomes a protoplast fully surrounded by the mother cell cytoplasm and separated from it by a double membrane system. Activation of sigma(G) also requires expression of spoIIIJ, coding for a membrane protein translocase of the YidC/Oxa1p/Alb3 family, and of the mother cell-specific spoIIIA operon. Here we present genetic and biochemical evidence indicating that SpoIIIAE, the product of one of the spoIIIA cistrons, and SpoIIIJ interact in the membrane, thereby linking the function of the spoIIIJ and spoIIIA loci in the activation of sigma(G). We also show that SpoIIIAE has a functional Sec-type signal peptide, which is cleaved during sporulation. Furthermore, mutations that reduce or eliminate processing of the SpoIIIAE signal peptide arrest sporulation following engulfment completion and prevent activation of sigma(G). SpoIIIJ-type proteins can function in cooperation with or independently of the Sec system. In one model, SpoIIIJ interacts with SpoIIIAE in the context of the Sec translocon to promote its correct localization and/or topology in the membrane, so that it can signal the activation of sigma(G) following engulfment completion. 相似文献
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D. van Erck C. D. Dolman M. Snaterse M. Tieland A. H. G. Driessen P. J. M. Weijs W. J. M. Scholte op Reimer J. P. Henriques J. D. Schoufour 《Netherlands heart journal》2021,29(9):460
BackgroundThe COVID-19 pandemic has led to a national lockdown in the Netherlands, which also affected transcatheter aortic valve implantation (TAVI) patients. The objective of the study was to describe physical activity, dietary intake and quality of life (QoL) in patients on the waiting list for TAVI pre-lockdown and during lockdown.MethodsConsecutive patients awaiting TAVI at the Amsterdam University Medical Centers, the Netherlands were included. Measurements were self-reported effect of lockdown, physical activity, dietary intake and QoL.ResultsIn total, 58 patients (median age 80, interquartile range (IQR) 76–84, 45% female) were observed pre-lockdown and 16 patients (median age 78, IQR 76–82, 25% female) during lockdown. Ten of the 16 patients during lockdown reported a decline in physical activity. However, we observed a median number of 5861 steps a day (IQR 4579–7074) pre-lockdown and 8404 steps a day (IQR 7653–10,829) during lockdown. Median daily protein intake was 69 g (IQR 59–82) pre-lockdown and 90 g (IQR 68–107) during lockdown. Self-rated health on a visual analogue scale was 63 points (IQR 51–74) pre-lockdown and 73 points (IQR 65–86) during lockdown.ConclusionsMore than half of the patients during lockdown reported less physical activity, while we observed a higher number of steps a day, a similar dietary intake and a higher QoL. Therefore, patients on the TAVI waiting list appeared to be able to cope with the lockdown measures. 相似文献
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Pedro Cardoso Sérgio S. Henriques Clara Gaspar Luis C. Crespo Rui Carvalho Jesper B. Schmidt Pedro Sousa Tamás Szűts 《Journal of Insect Conservation》2009,13(1):45-55
Intensive fieldwork has been undertaken in Portugal in order to develop a standardized and optimized sampling protocol for
Mediterranean spiders. The present study had the objectives of testing the use of semi-quantitative sampling for obtaining
an exhaustive species richness assessment of spiders and testing the effects of day, time of day, collector and sampling method
on the collected species richness and composition of a Mediterranean scrubland. The collecting summed 224 samples corresponding
to one person-hour of effective fieldwork each. In total, 115 species were captured, of which 110 were recorded inside a delimited
one-hectare plot, corresponding to more than 70% of the about 160 estimated species. Although no estimator reached the asymptote,
the Michaelis-Menten curve behaviour indicates that the estimated richness should be accurate. Most different sampling approaches
(day, time of day, collector and sampling method) were found to influence richness, abundance or composition of the samples
to some extent, although sampling method had the strongest influence whereas “collector” showed no effect at all. The results
support the idea that the only variables that need to be controlled in similar protocols are the sampling methods and the
time of day when each method is executed. We conclude that populations in structurally simple habitats present narrower peaks
of adult abundance, which implies higher percentages of juveniles in samples. Finally, results also indicate that habitats
with a relatively simple structure like scrublands may require as much sampling effort, in order to reach similar proportions
of captured species in relation to the estimated richness, as habitats that are much more complex. 相似文献