排序方式: 共有66条查询结果,搜索用时 15 毫秒
61.
Cao J Papadopoulou N Kempuraj D Boucher WS Sugimoto K Cetrulo CL Theoharides TC 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(12):7665-7675
Mast cells are critical for allergic reactions, but also for innate or acquired immunity and inflammatory conditions that worsen by stress. Corticotropin-releasing hormone (CRH), which activates the hypothalamic-pituitary-adrenal axis under stress, also has proinflammatory peripheral effects possibly through mast cells. We investigated the expression of CRH receptors and the effects of CRH in the human leukemic mast cell (HMC-1) line and human umbilical cord blood-derived mast cells. We detected mRNA for CRH-R1alpha, 1beta, 1c, 1e, 1f isoforms, as well as CRH-R1 protein in both cell types. CRH-R2alpha (but not R2beta or R2gamma) mRNA and protein were present only in human cord blood-derived mast cells. CRH increased cAMP and induced secretion of vascular endothelial growth factor (VEGF) without tryptase, histamine, IL-6, IL-8, or TNF-alpha release. The effects were blocked by the CRH-R1 antagonist antalarmin, but not the CRH-R2 antagonist astressin 2B. CRH-stimulated VEGF production was mediated through activation of adenylate cyclase and increased cAMP, as evidenced by the fact that the effect of CRH was mimicked by the direct adenylate cyclase activator forskolin and the cell-permeable cAMP analog 8-bromo-cAMP, whereas it was abolished by the adenylate cyclase inhibitor SQ22536. This is the first evidence that mast cells express functional CRH receptors and that CRH can induce VEGF secretion selectively. CRH-induced mast cell-derived VEGF could, therefore, be involved in chronic inflammatory conditions associated with increased VEGF, such as arthritis or psoriasis, both of which worsen by stress. 相似文献
62.
Theocharis AD Karamanos NK Papageorgakopoulou N Tsiganos CP Theocharis DA 《Biochimica et biophysica acta》2002,1569(1-3):117-126
The content, types and the fine structures of proteoglycans (PGs) present in human normal nasal cartilage (HNNC) were investigated and compared with those in human scoliotic nasal cartilage (HSNC). Three PG types were identified in both HNNC and HSNC; the large-sized high buoyant density aggrecan, which is the predominant PG population, and the small-sized low buoyant density biglycan and decorin. HSNC contained a significantly higher amount of keratan sulfate (KS)-rich aggrecan (30%) of smaller hydrodynamic size as compared to HNNC. The average molecular sizes (M(r)s) of aggecan-derived chondroitin sulfate (CS) chains in both HNNC and HSNC were identical (18 kDa), but they significantly differ in disaccharide composition, since CS isolated from HSNC contained higher proportions of 6-sulfated disaccharides as compared to those from HNNC. Scoliotic tissue contained also higher amounts (67%) of the small PGs, biglycan and decorin as compared to HNNC. It is worth noticing that both normal and scoliotic human nasal cartilage contain also non-glycanated forms of decorin and biglycan. Dermatan sulfate (DS) was the predominant glycosaminoglycan (GAG) present on biglycan and decorin in both tissues. The small PGs-derived CS chains in both normal and scoliotic cartilage had the same M(r) (20 kDa), whereas DS chains from scoliotic cartilage were of greater M(r) (32 kDa) than those from normal cartilage (24 kDa). Furthermore, scoliotic tissue-derived DS chains contained higher amounts of iduronate (20%) as compared to those of normal cartilage (12%). Disaccharide analysis of small PGs showed that both HNNC and HSNC were rich in 4-sulfated disaccharides and in each case, the small size PGs contained a considerably higher proportion of 4-sulfated disaccharides than the aggrecan of the same tissue. The higher amounts of matrix PGs identified in scoliotic tissue as well as the differences in fine chemical composition of their GAG chains may reflect the modified architecture and functional failure of scoliotic tissue. 相似文献
63.
Moschopoulou G Papanastasiou I Makri O Lambrou N Economou G Soukouli K Kintzios SE 《Plant cell reports》2007,26(12):2063-2069
We investigated a possible relationship between the levels of reactive oxygen species (ROS) and the stimulation of frond division
of the aquatic plant Spirodela polyrrhiza (duckweed) during a 7-day experimental culture period. In particular, we monitored superoxide concentration using a state-of-the-art
cell biosensor. A considerable reduction in ROS and superoxide concentration was observed during the first 2 days of culture,
whereas duckweed cultures achieved near exponential growth rates after the second day. In addition, apoptotic markers such
as the cytoplasmic concentration of cytochrome c, mitochondrial membrane depolarization and the activity of caspase-3 declined during the culture period and at least before
daughter frond maturation. We suggest that S. polyrrhiza frond division may have been stimulated by the observed reduction of free radicals and the associated avoidance of cell apoptotic
pathways in cultured plants. 相似文献
64.
Natural isothiocyanates (ITCs) are toxic to a range of soil-borne pest and pathogens, including nematodes and fungi, and can thus be used as natural fumigants called biofumigants. Glucosinolates, β-thioglucoside N-hydroxysulfates, are secondary metabolites of Brassicales plants, stored in the S-cells vacuoles. Upon plant tissue damage myrosinase (thioglucoside glycohydrolase, EC 3.2.3.1), stored in contiguous cells, hydrolyses glucosinalates to an unstable aglycone that eventually eliminates sulfate group producing a wide range of different volatile isothiocyanates that are extremely toxic to root-knot nematodes. In fact, among synthetic commercial nematicidal formulates we can find isothiocyanates as active ingredients. Conventional nematode control practices have included soil sterilants of great environmental impact, most of which are now banned making mandatory the development of eco-sustainable alternative tools. We reviewed the nematicidal activity of isothiocyanates as components of botanical matrixes in the frame of a holistic nematode control approach encompassing secondary beneficial effects on soil structure and microbiology, beneficial preservation, enhanced residual life of biological activity and plant growth. 相似文献
65.
Nikoletta Ntalli Antonis Michaelakis Kodjo Eloh Dimitrios P Papachristos Lukasz Wejnerowski Pierluigi Caboni Slawek Cerbin 《Journal of applied phycology》2017,29(3):1297-1305
Biocidal natural substances of botanical origin offer a promising ecofriendly option for controlling toxic cyanobacteria. Herein, we study 11 essential oils and some of their major components for their activity on Aphanizomenon gracile. On the basis of our results we support that Origanum vulgare and O. dictamnus, Ocimum basilicum, Eucalyptus meliodora, Melissa officinalis, and Pimpinella anisum exhibited the strongest activities, and the IC50/1d values of the extracts were calculated to be between 168.43 and 241.97 μg mL?1. When the major components of the biocidal essential oils were tested individually, (E)-anethole was found active, exhibiting an IC50/1d value of 71.35 μg mL?1. On the other hand, the half-life (t 1/2 ) of (E)-anethole was calculated at 1 h. A preliminary attempt of (E)-anethole microencapsulation was conducted, in order to slowly release this biocidal agent, increasing the residual life under open air conditions and thus the biological activity. Results were promising since the microencapsulated product exhibited better activity than did the non-formulated (E)-anethole. This is a first report on the biocidal activity of EOs and (E)-anethole on A. gracile and a preliminary indication of the microencapsulated (E)-anethole potential use as a natural biocidal in fresh waters. 相似文献
66.
András Kosztolányi Nikoletta Nagy Tibor Kovács Zoltán Barta 《Entomological Science》2015,18(2):292-294
Although intensive care for offspring by both parents is rare in arthropods, it occurs in some species including the beetle Lethrus apterus. According to previous publications, in this species the male collects leaves, which are used by the female to form balls in the underground nest burrow. These balls serve as food for the hatched offspring. Most knowledge about the behavior of this species is based on information collected more than a century ago. Therefore, we investigated above‐ground breeding behavior and the status of nest burrows of this beetle in its natural habitat in Hungary. Our results suggest that contrary to previously documented cases, above‐ground parental care, i.e. the collection of leaves, is done predominantly not by the males but the females. Further research is needed to understand the role of the sexes in parental care in this species and to explain the discrepancy between the previously documented cases and the results we report here. 相似文献