共查询到20条相似文献,搜索用时 16 毫秒
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Chronic inflammation induced by Helicobacter pylori infection is a critical factor in the development of peptic ulcer disease and gastric cancer. Central to this inflammation is the initiation of pro‐inflammatory signaling cascades within epithelial cells, in particular those mediated by two sensors of bacterial cell wall components, nucleotide‐binding oligomerization domain‐containing protein 1 (NOD1) and alpha‐protein kinase 1 (ALPK1). H pylori is, however, also highly adept at mitigating inflammation in the host, thereby restricting tissue damage and favoring bacterial persistence. H pylori modulates host immune responses by altering cytokine signaling in epithelial and myeloid cells, which results in increased proliferation of regulatory T cells and downregulation of effector T‐cell responses. H pylori vacuolating cytotoxin A (VacA) has been shown to play an important role in the dampening of immune responses and induction of immune tolerance capable of protecting against asthma. It is also possible to generate protective immune responses by immunization with various H pylori antigens or their epitopes, in combination with an adjuvant, though this for now has only been shown in mouse models. Novel non‐toxic adjuvants, consisting of modified bacterial enterotoxins or nanoparticles, have recently been developed that may not only enhance vaccine efficacy, but also help translate candidate vaccines to the clinic. This review will summarize the main discoveries in the past year regarding host immune responses to H pylori infection, as well as the design of new vaccine approaches against this infection. 相似文献
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Paul M. Peterson Konstantin Romaschenko Yolanda Herrera Arrieta Maria S. Vorontsova 《植物分类学报:英文版》2022,60(3):630-639
To investigate the evolutionary relationships among species of Afrotrichloris, Apochiton, Coelachyrum, Dinebra, Eleusine, Leptochloa, and Schoenefeldia of subtribe Eleusininae, a phylogeny based on DNA sequences from nine gene regions (ITS, rps16-trnK, rps3, rps16, rpoC2, rpl32-trnL, ndhF, ndhA, ccsA) is presented. Previous molecular phylogenies indicated that Coelachyrum was polyphyletic and Schoenefeldia was paraphyletic, with Afrotrichloris embedded within it. Apochiton burttii was embedded in the Coelachyrum clade paired with C. longiglume, Coelachyrumpoiflorum was placed outside of Coelachyrum and sister to Eleusine, and Schoenefeldia is paraphyletic, with its two species forming a grade sister to Afrotrichoris. Our molecular phylogeny supports recognition of a new genus, Schoenefeldiella, and a new combination, Schoenfeldiella transiens. In addition, we provide generic emendations for Coelachyrum, which now includes five species including a new combination proposed here, Coelachyrum burttii, and Eleusine, which now includes 11 species. 相似文献
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The social play behavior of six mammalian species (Rodentia,Pinnipedia, Artiodactyla, Carnivora) is described and compared.Locomotor and Rotational Movements, e.g., jumping, running,and headshaking, occurred in all species and predominated inthe rodent play. These movements are similar in form to anti-predatorand "protective" responses and result in an immediate but temporarycessation of sensory stimulation from conspecifics. Investigation of body odors was the most important stimuluseliciting Locomotor-Rotational Movements in the rodents. Inthe larger mammals, body odor sniffing was enhanced during play,but specialized signals from other sensory modalities elicitedand maintained play interactions. The possible functions ofa heightened exchange of olfactory information during juvenilesocial development are discussed. 相似文献
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Basal cell carcinoma (BCC) is the most common malignancy. Exposure to sunlight is the most important risk factor. Most, if not all, cases of BCC demonstrate overactive Hedgehog signaling. A variety of treatment modalities exist and are selected based on recurrence risk, importance of tissue preservation, patient preference, and extent of disease. The pathogenesis, epidemiology, clinical features, diagnosis, histopathology, and management of BCC will be discussed in this review. 相似文献
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<正> 本书系由昆虫各重要类群的细胞内共生物的专家写成。其重点是:它们形态学的电镜研究、寄主与共生物的相互关系、寄主的免疫系统、共生物的遗传学及基因表达、它们的系统发育和分类等。目前已知,在蟑螂、白蚁、蚂蚁、蝉、蚧虫、蚜虫、蝇类、甲虫及蜱类中均有细胞内共生物。 相似文献
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Journal of Biological Physics - 相似文献
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Islands: stability, diversity, conservation 总被引:1,自引:0,他引:1
Q. C. B. Cronk 《Biodiversity and Conservation》1997,6(3):477-493
Islands present both a diversity and a stability paradox. They are often highly species-poor but have considerable biological interest in terms of extraordinary endemic genera and taxonomically isolated groups. They appear to be stable, as in some cases these organisms have persisted for many millions of years, and having an oceanic climate, extreme climatic events may be comparatively rare. However, when subject to extrinsic (anthropogenic) disturbance they do not appear to be stable, but often suffer catastrophic ecological change. These apparent paradoxes are resolved when it is realized that all these features are consequences of the same island characteristics: biotic isolation and oceanicity. As a result of these two characteristics, far oceanic islands are quantitatively different from continental systems in the nature of their ecological processes, which appear to give rise to an extreme punctuated equilibrium model of evolutionary change. Endemics may be ancient relict endemics displaying prolonged stasis and persistence, or products of adaptive radiation representing rapid punctuational events. A process-based definition of a relict endemic (palaeoendemic) is one whose founding lineage (i.e. the original continental source taxon) has not left any descendents. A corollary of this definition is that the time of divergence between an endemic and its continental sister-group should predate the colonization of the island by the now endemic lineage. An example is Dicksonia arborescens which has been on St Helena for at least 9 Myrs and no longer occurs in the likely source area of Africa. These relict endemics, frequent on islands, are important as the last remnants of tranches of biodiversity that have vanished elsewhere. Island conservation strategies require an integrated understanding of both sides of the diversity and stability paradox so that both island processes and island organisms can be conserved. 相似文献
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Vorotnikov AV 《Biochemistry. Biokhimii?a》2011,76(13):1528-1555
This review focuses on basic principles of motility in different cell types, formation of the specific cell structures that
enable directed migration, and how external signals are transduced into cells and coupled to the motile machinery. Feedback
mechanisms and their potential role in maintenance of internal chemotactic gradients and persistence of directed migration
are highlighted. 相似文献
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Ubiquitin: structures, functions, mechanisms 总被引:23,自引:0,他引:23
Ubiquitin is the founding member of a family of structurally conserved proteins that regulate a host of processes in eukaryotic cells. Ubiquitin and its relatives carry out their functions through covalent attachment to other cellular proteins, thereby changing the stability, localization, or activity of the target protein. This article reviews the basic biochemistry of these protein conjugation reactions, focusing on ubiquitin itself and emphasizing recent insights into mechanism and specificity. 相似文献