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71.
72.
Roncero MI Di Pietro A Ruiz-Roldán MC Huertas-González MD Garcia-Maceira FI Méglecz E Jiménez A Caracuel Z Sancho-Zapatero R Hera C Gómez-Gómez E Ruiz-Rubio M González-Verdejo CI Páez MJ 《Revista iberoamericana de micología》2000,17(1):S47-S53
Fusarium oxysporum invades its host plants through the roots and colonizes the vascular system. It produces a great variety of cell-wall degrading enzymes (CWDE), such as cellulases, xylanases, pectinases and proteases. Our group has purified and characterized an endopolygalacturonase (PG1), two exopolygalacturonases (PG2 and PG3), an endoxylanase (XYL1) and an endo pectatelyase (PL1). We have isolated the following CWDE-encoding genes: pg1, pgx4, pg5, xyl2, xyl3, prt1 and pl1. Gene expression in different culture conditions has been determined by Northern analysis. The occurrence of these genes in different formae speciales has been analyzed by Southern analysis and PCR. All these genes are expressed during different stages of the interaction with the host plant indicating a possible role in pathogenesis. At present, targeted gene disruption is being carried out, in order to determine the role of each gene in the pathogenicity process. 相似文献
73.
Lázaro-Diéguez F Jiménez N Barth H Koster AJ Renau-Piqueras J Llopis JL Burger KN Egea G 《Cell motility and the cytoskeleton》2006,63(12):778-791
Here we examine the contribution of actin dynamics to the architecture and pH of the Golgi complex. To this end, we have used toxins that depolymerize (cytochalasin D, latrunculin B, mycalolide B, and Clostridium botulinum C2 toxin) or stabilize (jasplakinolide) filamentous actin. When various clonal cell lines were examined by epifluorescence microscopy, all of these actin toxins induced compaction of the Golgi complex. However, ultrastructural analysis by transmission electron microscopy and electron tomography/three-dimensional modelling of the Golgi complex showed that F-actin depolymerization first induces perforation/fragmentation and severe swelling of Golgi cisternae, which leads to a completely disorganized structure. In contrast, F-actin stabilization results only in cisternae perforation/fragmentation. Concomitantly to actin depolymerization-induced cisternae swelling and disorganization, the intra-Golgi pH significantly increased. Similar ultrastructural and Golgi pH alkalinization were observed in cells treated with the vacuolar H+ -ATPases inhibitors bafilomycin A1 and concanamycin A. Overall, these results suggest that actin filaments are implicated in the preservation of the flattened shape of Golgi cisternae. This maintenance seems to be mediated by the regulation of the state of F-actin assembly on the Golgi pH homeostasis. 相似文献
74.
We studied the infection dynamics and maturation cycle of Oligogonotylus manteri in wild and caged 'Cichlasoma' urophthalmus, and determined the potential role of different sources of infection in its transmission in a quarry (MITZA). Metacercariae, and nongravid and gravid stages of O. manteri were present throughout 1 annual cycle. Prevalence, mean intensity, and/or aggregation values peaked around April and June in both wild and caged fish. This period of time includes the start of the rainy season, in which the water temperature reaches its maximum annual values. Because temperature is a major factor triggering 'C.' urophthalmus activity (food intake, growth, and reproduction), and O. manteri metacercariae and adults are trophically transmitted, temperature may be playing an important role in the recruitment of worms to the fish. We also determined that cercariae infect caged fish through a mechanism other than trophic transmission whereby fish consume infected snails, which has been described as the most common mode of transmission to 'C.' urophthalmus. 相似文献
75.
76.
Mogens K. Boisen Christian Dehlendorff Dorte Linnemann Boye S. Nielsen Jim S. Larsen Kell ?sterlind Svend E. Nielsen Line S. Tarpgaard Camilla Qvortrup Per Pfeiffer Niels H. Holl?nder Nina Keldsen Torben F. Hansen Brita B. Jensen Estrid V. S. H?gdall Benny V. Jensen Julia S. Johansen 《PloS one》2014,9(10)
Purpose
We tested the hypothesis that expression of microRNAs (miRNAs) in cancer tissue can predict effectiveness of bevacizumab added to capecitabine and oxaliplatin (CAPEOX) in patients with metastatic colorectal cancer (mCRC).Experimental Design
Patients with mCRC treated with first line CAPEOX and bevacizumab (CAPEOXBEV): screening (n = 212) and validation (n = 121) cohorts, or CAPEOX alone: control cohort (n = 127), were identified retrospectively and archival primary tumor samples were collected. Expression of 754 miRNAs was analyzed in the screening cohort using polymerase chain reaction (PCR) arrays and expression levels were related to time to disease progression (TTP) and overall survival (OS). Significant miRNAs from the screening study were analyzed in all three cohorts using custom PCR arrays. In situ hybridization (ISH) was done for selected miRNAs.Results
In the screening study, 26 miRNAs were significantly correlated with outcome in multivariate analyses. Twenty-two miRNAs were selected for further study. Higher miR-664-3p expression and lower miR-455-5p expression were predictive of improved outcome in the CAPEOXBEV cohorts and showed a significant interaction with bevacizumab effectiveness. The effects were strongest for OS. Both miRNAs showed high expression in stromal cells. Higher expression of miR-196b-5p and miR-592 predicted improved outcome regardless of bevacizumab treatment, with similar effect estimates in all three cohorts.Conclusions
We have identified potentially predictive miRNAs for bevacizumab effectiveness and additional miRNAs that could be related to chemotherapy effectiveness or prognosis in patients with mCRC. Our findings need further validation in large cohorts, preferably from completed randomized trials. 相似文献77.
This work describes the long-term acclimation of the halotolerant microalga Dunaliella viridis to different photon irradiance, ranging from darkness to 1500 μmol m−2 s−1. In order to assess the effects of long-term photoinhibition, changes in oxygen production rate, pigment composition, xanthophyll
cycle and in vivo chlorophyll fluorescence using the saturating pulse method were measured. Growth rate was maximal at intermediate irradiance
(250 and 700 μmol m−2 s−1). The increase in growth irradiance from 700 to 1500 μmol m−2 s−1 did not lead to further significant changes in pigment composition or EPS, indicating saturation in the pigment response
to high light. Changes in Photosystem II optimum quantum yield (Fv/Fm) evidenced photoinhibition at 700 and especially at 1500 μmol m−2 s−1. The relation between photosynthetic electron flow rate and photosyntetic O2 evolution was linear for cultures in darkness shifting to curvilinear as growth irradiance increased, suggesting the interference
of the energy dissipation processes in oxygen evolution. Carbon assimilation efficiencies were studied in relation to changes
in growth rate, internal carbon and nitrogen composition, and organic carbon released to the external medium. All illuminated
cultures showed a high capability to maintain a C:N ratio between 6 and 7. The percentage of organic carbon released to the
external medium increased to its maximum under high irradiance (1500 μmol m−2 s−1). These results suggest that the release of organic carbon could act as a secondary dissipation process when the xanthophyll
cycle is saturated.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
78.
The oxidized state of rusticyanin, the blue copper protein with the highest redox potential in its class, has been investigated through (1)H nuclear magnetic resonance applied to its cobalt(II) derivative. The assignment of the protons belonging to the coordinated residues has been performed. Many other amino acids situated in the vicinity of the metal ion, including six hydrophobic residues (isoleucine140 and five phenylalanines) have also been identified. The orientation of the main axes of the magnetic susceptibility tensor for the cobalt(II)-rusticyanin as well as its axial, Deltachi(ax), and rhombic, Deltachi(rh), magnetic susceptibility anisotropy components have been determined. A comparison of the present results with those previously obtained for cobalt(II)azurin [Donaire, A., Salgado, J., Moratal, J. M. (1998) Biochemistry 37, 8659-8673] allows us to provide further insights into the reasons for the high redox potential of this protein. According to our results, the interaction between the metal ion and the thioether Sdelta of the axial methionine is not as influential as the strong destabilizing effect that the hydrophobic residues close to the metal ion undergo in the oxidized state. 相似文献
79.
The macroecology of infectious diseases: a new perspective on global‐scale drivers of pathogen distributions and impacts 下载免费PDF全文
Patrick R. Stephens Sonia Altizer Katherine F. Smith A. Alonso Aguirre James H. Brown Sarah A. Budischak James E. Byers Tad A. Dallas T. Jonathan Davies John M. Drake Vanessa O. Ezenwa Maxwell J. Farrell John L. Gittleman Barbara A. Han Shan Huang Rebecca A. Hutchinson Pieter Johnson Charles L. Nunn David Onstad Andrew Park Gonzalo M. Vazquez‐Prokopec John P. Schmidt Robert Poulin 《Ecology letters》2016,19(9):1159-1171
Identifying drivers of infectious disease patterns and impacts at the broadest scales of organisation is one of the most crucial challenges for modern science, yet answers to many fundamental questions remain elusive. These include what factors commonly facilitate transmission of pathogens to novel host species, what drives variation in immune investment among host species, and more generally what drives global patterns of parasite diversity and distribution? Here we consider how the perspectives and tools of macroecology, a field that investigates patterns and processes at broad spatial, temporal and taxonomic scales, are expanding scientific understanding of global infectious disease ecology. In particular, emerging approaches are providing new insights about scaling properties across all living taxa, and new strategies for mapping pathogen biodiversity and infection risk. Ultimately, macroecology is establishing a framework to more accurately predict global patterns of infectious disease distribution and emergence. 相似文献
80.
Claudia Geue Olivia Wu Yiqiao Xin Robert Heggie Sharon Hutchinson Natasha K. Martin Elisabeth Fenwick David Goldberg Consortium ECDC 《PloS one》2015,10(12)