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排序方式: 共有2730条查询结果,搜索用时 15 毫秒
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Bethany M. Henrick Lucie Rodriguez Tadepally Lakshmikanth Christian Pou Ewa Henckel Aron Arzoomand Axel Olin Jun Wang Jaromir Mikes Ziyang Tan Yang Chen Amy M. Ehrlich Anna Karin Bernhardsson Constantin Habimana Mugabo Ylva Ambrosiani Anna Gustafsson Stephanie Chew Heather K. Brown Petter Brodin 《Cell》2021,184(15):3884-3898.e11
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Mats-Jerry Eriksson Jenny Schelin Ewa Miskiewicz Adrian K. Clarke 《Journal of bacteriology》2001,183(24):7392-7396
Synechococcus sp. strain PCC 7942 has a second clpB gene that encodes a 97-kDa protein with novel features. ClpBII is the first ClpB not induced by heat shock or other stresses; it is instead an essential, constitutive protein. ClpBII is unable to complement ClpBI function for acquired thermotolerance. No truncated ClpBII version is normally produced, unlike other bacterial forms, while ectopic synthesis of a putative truncated ClpBII dramatically decreased cell viability. 相似文献
6.
Over 100 of Pseudomonas aeruginosa isolates representing the two TTSS genotypes (exoU
−/exoS
+ or exoU
+/exoS
−) were cultured in different media in order to evaluate their proteolytic activities and find a relationship between proteolytic
activity and the cytotoxic and/or invasive phenotypes displayed by the strains upon infection of RAW 264.7 murine macrophage-like
cells and pulmonary microvascular endothelial cells (PME). The elastolytic activity, protein concentration, and total proteolytic
activity (TPA) were measured in culture supernatants. No significant differences were observed in the median elastolytic activities
among cytotoxic/noninvasive, noncytotoxic/invasive, and cytotoxic/invasive phenotypes displayed by P. aeruginosa strains. The only significant difference was noted when isolates of the two different TTSS genotypes were grown in a calcium-depleted
minimal medium for induction of TTSS (MI). The exoU
−/exoS
+ isolates showed significant higher levels of the median elastolytic activity when compared to the exoU
+/exoS
− isolates. These two groups of isolates secreted the elastase B (LasB) with distinct molecular masses 158 or 116 kD, respectively.
The strains of the two TTSS genotypes secreted similar amount of total proteins; however, the higher values of TPA were observed
for the isolates of the exoU
+
/exoS
− genotype when grown in MI medium. We concluded that there is no direct relationship between secretion of proteases with elastolytic
activity and the cytotoxic and/or invasive phenotypes of the isolates observed upon infection of both RAW 264.7 and PME monolayers.
Further studies are needed to find out whether others factors beside proteases could influence the mechanism of host cells
intoxication mediated by the P. aeruginosa TTSS-delivered toxins. 相似文献
7.
Ewa Symonides 《Plant Ecology》1988,77(1-3):21-31
This paper is concerned with the effect of disturbance on some crucial characteristics of annual plants. The theoretically optimal life-history traits that maximize individual fitness in disturbed environments are described and critically evaluated. It seems that none of them holds for all annual species.Self-pollination and especially seed polymorphism are considered important adaptations to life in unpredictable environments. The thesis is put forward that amphicarpic annuals, which exhibit both self-pollination and extreme seed polymorphism, are best adapted to life in hazardous habitats. The hypothetical course of the evolution of amphicarpy is demonstrated on the grounds of the comparison of contemporary annual species producing chasmogamous and cleistogamous flowers on a single individual. 相似文献
8.
Toby J. Lloyd-Jones Mark V. Roberts E. Charles Leek Nathalie C. Fouquet Ewa G. Truchanowicz 《PloS one》2012,7(11)
Little is known about the timing of activating memory for objects and their associated perceptual properties, such as colour, and yet this is important for theories of human cognition. We investigated the time course associated with early cognitive processes related to the activation of object shape and object shape+colour representations respectively, during memory retrieval as assessed by repetition priming in an event-related potential (ERP) study. The main findings were as follows: (1) we identified a unique early modulation of mean ERP amplitude during the N1 that was associated with the activation of object shape independently of colour; (2) we also found a subsequent early P2 modulation of mean amplitude over the same electrode clusters associated with the activation of object shape+colour representations; (3) these findings were apparent across both familiar (i.e., correctly coloured – yellow banana) and novel (i.e., incorrectly coloured - blue strawberry) objects; and (4) neither of the modulations of mean ERP amplitude were evident during the P3. Together the findings delineate the timing of object shape and colour memory systems and support the notion that perceptual representations of object shape mediate the retrieval of temporary shape+colour representations for familiar and novel objects. 相似文献
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