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1.
Many bark beetles live in a symbiosis with ophiostomatoid fungi but very little is known regarding these fungi in Spain. In this study, we considered the fungi associated with nine bark beetle species and one weevil infesting two native tree species (Pinus sylvestris and Pinus nigra) and one non-native (Pinus radiata) in Cantabria (Northern Spain). This included examination of 239 bark beetles or their galleries. Isolations yielded a total of 110 cultures that included 11 fungal species (five species of Leptographium sensu lato including Leptographium absconditum sp. nov., five species of Ophiostoma sensu lato including Ophiostoma cantabriense sp. nov, and one species of Graphilbum). The most commonly encountered fungal associates of the bark beetles were Grosmannia olivacea, Leptographium procerum, and Ophiostoma canum. The aggressiveness of the collected fungal species was evaluated using inoculations on two-year-old P. radiata seedlings. Leptographium wingfieldii, Leptographium guttulatum, and Ophiostoma ips were the only species capable of causing significant lesions.  相似文献   
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Five clones, containing polymorphic CA-repeat sequences, have been isolated from a specific human chromosome 21 phage library and have been localised to band q21 of chromosome 21 using a somatic cell hybrid panel. These highly repetitive sequences (D21S1263, D21S1264, D21S1415, D21S1417 and D21S1420) have been characterised in the CEPH reference parents and have heterozygosities ranging from 0.30 to 0.81 and an average polymorphism information content (PIC) of 0.62. The relative order of these markers, based on the somatic cell hybrid panel, is cen-D21S1417, D21S1420-D21S1263, D21S1415-D21S1264-tel. The most polymorphic marker (D21S1264) has been included in the chromosome 21 genetic map. They have also been localised in the CEPH/ Généthon YAC panel, providing a refined localisation of these polymorphic sequences. These five CA-repeat markers should provide a better characterisation of the q21 region of chromosome 21.  相似文献   
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Human Vgamma9delta2 T lymphocytes are suggested to play an important role in the immune response to various microbial pathogens. In contrast to alphabeta T cells, gammadelta T lymphocytes recognize small, non-protein, phosphate-bearing antigens (phosphoantigens) in a major histocompatibility complex-independent manner. Four different phosphoantigens termed TUBag1 to TUBag4 with a common 3-formyl-1-butyl-pyrophosphate moiety and isopentenyl-pyrophosphate have been isolated and identified from mycobacteria. However, natural occurring gammadelta T cell ligands from other bacterial species were not characterized so far. Here, we describe the structural identification of the two compounds responsible for the gammadelta T cell-stimulating capacity of Escherichia coli as similar to the mycobacterial phosphoantigens 3-formyl-1-butyl-pyrophosphate and its M(r) 275 homologue TUBag2. In addition, E. coli phosphoantigens exert bioactivities on gammadelta T cells with similar potencies to the mycobacterial phosphoantigens at 5-15 nm concentration. Furthermore, our results clearly prove that the deoxyxylulose 5-phophate pathway (also referred to as Rohmer metabolic route of isoprenoid biosynthesis) is essential for the biosynthesis of the phosphoantigens in E. coli. Because this pathway is absent from human cells, it proves an ideal target for focusing efficiently the antimicrobial selectivity of human gammadelta T lymphocytes.  相似文献   
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Purpose

Rapid weight reduction is part of the pre-competition routine and has been shown to negatively affect psychological and physiological performance of Taekwondo (TKD) athletes. This is caused by a reduction of the body water and an electrolyte imbalance. So far, it is unknown whether weight reduction also affects hemorheological properties and hemorheology-influencing nitric oxide (NO) signaling, important for oxygen supply to the muscles and organs.

Methods

For this purpose, ten male TKD athletes reduced their body weight by 5% within four days (rapid weight reduction, RWR). After a recovery phase, athletes reduced body weight by 5% within four weeks (gradual weight reduction, GWR). Each intervention was preceded by two baseline measurements and followed by a simulated competition. Basal blood parameters (red blood cell (RBC) count, hemoglobin concentration, hematocrit, mean corpuscular volume, mean cellular hemoglobin and mean cellular hemoglobin concentration), RBC-NO synthase activation, RBC nitrite as marker for NO synthesis, RBC deformability and aggregation parameters were determined on a total of eight investigation days.

Results

Basal blood parameters were not affected by the two interventions. In contrast to GWR, RWR decreased activation of RBC-NO synthase, RBC nitrite, respective NO concentration and RBC deformability. Additionally, RWR increased RBC aggregation and disaggregation threshold.

Conclusion

The results point out that a rapid weight reduction negatively affects hemorheological parameters and NO signaling in RBC which might limit performance capacity. Thus, GWR should be preferred to achieve the desired weight prior to a competition to avoid these negative effects.  相似文献   
8.
Cancer progression towards metastasis follows a defined sequence of events described as the metastatic cascade. For extravasation and transendothelial migration metastatic cells interact first with endothelial cells. Yet the role of endothelial cells during the process of metastasis formation and extravasation is still unclear, and the interaction between metastatic and endothelial cells during transendothelial migration is poorly understood. Since tumor cells are well known to express TGF-β, and the compact endothelial layer undergoes a series of changes during metastatic extravasation (cell contact disruption, cytoskeletal reorganization, enhanced contractility), we hypothesized that an EndMT may be necessary for metastatic extravasation. We demonstrate that primary cultured rat brain endothelial cells (BEC) undergo EndMT upon TGF-β1 treatment, characterized by the loss of tight and adherens junction proteins, expression of fibronectin, β1-integrin, calponin and α-smooth muscle actin (SMA). B16/F10 cell line conditioned and activated medium (ACM) had similar effects: claudin-5 down-regulation, fibronectin and SMA expression. Inhibition of TGF-β signaling during B16/F10 ACM stimulation using SB-431542 maintained claudin-5 levels and mitigated fibronectin and SMA expression. B16/F10 ACM stimulation of BECs led to phosphorylation of Smad2 and Smad3. SB-431542 prevented SMA up-regulation upon stimulation of BECs with A2058, MCF-7 and MDA-MB231 ACM as well. Moreover, B16/F10 ACM caused a reduction in transendothelial electrical resistance, enhanced the number of melanoma cells adhering to and transmigrating through the endothelial layer, in a TGF-β-dependent manner. These effects were not confined to BECs: HUVECs showed TGF-β-dependent SMA expression when stimulated with breast cancer cell line ACM. Our results indicate that an EndMT may be necessary for metastatic transendothelial migration, and this transition may be one of the potential mechanisms occurring during the complex phenomenon known as metastatic extravasation.  相似文献   
9.

Aim

To investigate RBC-NOS dependent NO signaling during in vivo RBC aging in health and disease.

Method

RBC from fifteen healthy volunteers (HC) and four patients with type 2 diabetes mellitus (DM) were separated in seven subpopulations by Percoll density gradient centrifugation.

Results

The proportion of old RBC was significantly higher in DM compared to HC. In both groups, in vivo aging was marked by changes in RBC shape and decreased cell volume. RBC nitrite, as marker for NO, was higher in DM and increased in both HC and DM during aging. RBC deformability was lower in DM and significantly decreased in old compared to young RBC in both HC and DM. RBC-NOS Serine1177 phosphorylation, indicating enzyme activation, increased during aging in both HC and DM. Arginase I activity remained unchanged during aging in HC. In DM, arginase I activity was significantly higher in young RBC compared to HC but decreased during aging. In HC, concentration of L-arginine, the substrate of RBC-NOS and arginase I, significantly dropped from young to old RBC. In DM, L-arginine concentration was significantly higher in young RBC compared to HC and significantly decreased during aging. In blood from healthy subjects, RBC-NOS activation was additionally inhibited by N5-(1-iminoethyl)-L-Ornithine dihydrochloride which decreased RBC nitrite, and impaired RBC deformability of all but the oldest RBC subpopulation.

Conclusion

This study first-time showed highest RBC-NOS activation and NO production in old RBC, possibly to counteract the negative impact of cell shrinkage on RBC deformability. This was even more pronounced in DM. It is further suggested that highly produced NO only insufficiently affects cell function of old RBC maybe because of isolated RBC-NOS in old RBC thus decreasing NO bioavailability. Thus, increasing NO availability may improve RBC function and may extend cell life span in old RBC.  相似文献   
10.
The deposition of the (1,3)-β-glucan cell wall polymer callose at sites of attempted penetration is a common plant defense response to intruding pathogens and part of the plant’s innate immunity. Infection of the Fusarium graminearum disruption mutant Δfgl1, which lacks the effector lipase FGL1, is restricted to inoculated wheat (Triticum aestivum) spikelets, whereas the wild-type strain colonized the whole wheat spike. Our studies here were aimed at analyzing the role of FGL1 in establishing full F. graminearum virulence. Confocal laser-scanning microscopy revealed that the Δfgl1 mutant strongly induced the deposition of spot-like callose patches in vascular bundles of directly inoculated spikelets, while these callose deposits were not observed in infections by the wild type. Elevated concentrations of the polyunsaturated free fatty acids (FFAs) linoleic and α-linolenic acid, which we detected in F. graminearum wild type-infected wheat spike tissue compared with Δfgl1-infected tissue, provided clear evidence for a suggested function of FGL1 in suppressing callose biosynthesis. These FFAs not only inhibited plant callose biosynthesis in vitro and in planta but also partially restored virulence to the Δfgl1 mutant when applied during infection of wheat spikelets. Additional FFA analysis confirmed that the purified effector lipase FGL1 was sufficient to release linoleic and α-linolenic acids from wheat spike tissue. We concluded that these two FFAs have a major function in the suppression of the innate immunity-related callose biosynthesis and, hence, the progress of F. graminearum wheat infection.The molecular and physiological regulation of the biosynthesis of callose, which is a (1,3)-β-glucan polymer with some (1,6)-branches (Aspinall and Kessler, 1957), and its importance for plant development as well as plant defense are still under examination. Regarding the involvement of callose in plant defense responses, particular attention has been focused on the formation of cell wall thickenings in plants, so-called papillae, at sites of microbial attack. They were already described 150 years ago (deBary, 1863) and reported to commonly contain callose (Mangin, 1895). Since then, examinations have identified callose as the most abundant chemical constituent in papillae, which may also include proteins (e.g. peroxidases and antimicrobial thionins), phenolics, and other constituents (Aist and Williams, 1971; Sherwood and Vance, 1976; Mims et al., 2000). Papillae have been regarded as an early defense reaction that may not completely stop the pathogen; rather, they have been considered to act as a physical barrier to slow pathogen invasion (Stone and Clarke, 1992; Voigt and Somerville, 2009) and to contribute to the plant’s innate immunity (Jones and Dangl, 2006; Schwessinger and Ronald, 2012). The host plant can gain time to initiate defense reactions that require gene activation and expression, such as the hypersensitive reactions, phytoalexin production, and pathogenesis-related protein synthesis (Lamb and Dixon, 1997; Brown et al., 1998). However, our recent study revealed that callose can also act as a barrier that completely prevents fungal penetration. The overexpression of POWDERY MILDEW RESISTANT4 (PMR4), a gene encoding a stress-induced callose synthase, resulted in early elevated callose deposition at sites of attempted powdery mildew penetration in Arabidopsis (Arabidopsis thaliana; Ellinger et al., 2013). Interestingly, the pmr4 deletion mutant also showed an increased resistance to powdery mildew that, however, was induced at later stages of powdery mildew infection because an initial fungal penetration still occurred. In fact, the absence of the functional callose synthase PMR4 in the pmr4 mutant resulted in papillae that were free from callose but also induced a hyperactivation of the salicylic acid defense pathway, which was shown to be the basis of resistance in double mutant and microarray analyses (Jacobs et al., 2003; Nishimura et al., 2003). The callose synthase gene PMR4 from Arabidopsis belongs to the GLUCAN SYNTHASE-LIKE (GSL) family, genes that have been identified in higher plants including wheat (Triticum aestivum; Cui et al., 2001; Doblin et al., 2001; Hong et al., 2001; Østergaard et al., 2002; Voigt et al., 2006). The predicted function of these genes as callose synthases is generally supported by homology with the yeast FK506 SENSITIVITY (FKS) genes, which are believed to be subunits of (1,3)-β-glucan synthase complexes (Douglas et al., 1994; Dijkgraaf et al., 2002). Additionally, the predicted proteins encoded by the GSL genes correlate with the approximately 200-kD catalytic subunit of putative callose synthases. Li et al. (2003) showed that the amino acid sequence predicted from a GSL gene in barley (Hordeum vulgare; HvGSL1) correlates with the amino acid sequence of an active (1,3)-β-glucan synthase fraction.In this study, we aimed to examine the involvement of callose synthesis and callose deposition in plant defense against intruding fungal pathogens in the pathosystem wheat-Fusarium graminearum. We focused on the ability of wheat to inhibit a further spread of fungal pathogens after an initial, successful infection. This resistance to fungal spread within the host has been referred to as type II resistance and is part of a widely accepted two-component system of resistance, which includes type I resistance operating against initial infection (Schroeder and Christensen, 1963). For our analyses, we used the direct interaction between wheat as host and F. graminearum as a pathogen. On the one hand, Fusarium head blight (FHB) of wheat, caused by F. graminearum, is one of the most destructive crop diseases worldwide (McMullen et al., 1997; del Blanco et al., 2003; Madgwick et al., 2011) and classifies this fungus as a top 10 plant pathogen based on its importance in science and agriculture (Dean et al., 2012). On the other hand, only a limited number of wheat cultivars were identified that revealed FHB resistance. However, these cultivars did not qualify for commercial cultivation or breeding approaches due to inappropriate agronomic traits (Buerstmayr et al., 2009). Further elucidation of the mechanisms of spreading resistance could support the generation of FHB-resistant wheat cultivars.In this regard, we demonstrated that the secreted lipase FGL1 of F. graminearum is a virulence factor required for wheat infection (Voigt et al., 2005). A strong resistance to fungal spread was observed in a susceptible wheat cultivar after infection with the lipase-deficient F. graminearum strain Δfgl1. Light microscopy indicated barrier formation in the transition zone of rachilla and rachis of directly inoculated spikelets. In contrast, neither spreading resistance nor barrier formation was observed during F. graminearum wild type infection. An active role of lipases in establishing full virulence was also recently proposed for the plant pathogen Fusarium oxysporum f. sp. lycopersici, where reduced lipolytic activity due to the deletion of lipase regulatory genes resulted in reduced colonization of tomato (Solanum lycopersicum) plants (Bravo-Ruiz et al., 2013). Because the expression of the lipase-encoding gene LIP1 was induced in the biotrophic fungus Blumeria graminis during early stages of infection (Feng et al., 2009) and disruption of the putative secreted lipase gene lipA resulted in reduced virulence of the bacterial plant pathogen Xanthomonas campestris (Tamir-Ariel et al., 2012), a general importance of extracellular lipolytic activity during plant colonization is indicated.We evaluated a possible role of callose in plant defense by infecting wheat spikes with the virulent fungal pathogen F. graminearum wild type, the virulence-deficient F. graminearum deletion mutant Δfgl1, and the barley leaf pathogen Pyrenophora teres, the latter intended to induce strong plant defense responses as known from incompatible, nonhost interactions. The formation of callose plugs within the vascular bundles of inoculated spikelets and the callose synthase activity of infected spikelet tissue correlated directly with increased plant resistance. Subsequent analyses of free fatty acid (FFA) concentrations revealed that those polyunsaturated FFAs were enriched during wheat infection with the F. graminearum wild-type strain that could inhibit callose synthase activity in vitro as well as in planta and partially restored the virulence of the lipase-deficient F. graminearum strain Δfgl1. On the basis of these results, we propose a model for FHB where defense-related callose synthase is inhibited by specific FFAs whose accumulation is caused by the fungus during fungal infection; this inhibition is required for full infection of the wheat head.  相似文献   
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