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991.
Vianey Marín‐Cevada Jesús Caballero‐Mellado Rocío Bustillos‐Cristales Jesús Muñoz‐Rojas Miguel A. Mascarúa‐Esparza Miguel Castañeda‐Lucio Lucía López‐Reyes Lourdes Martínez‐Aguilar Luis E. Fuentes‐Ramírez 《Journal of Phytopathology》2010,158(2):93-99
Pink disease is a major problem in the pineapple canning industry. Affected fruit acquire a brownish pigment after pasteurization and can contaminate non‐affected fruit before they are released to the consumer. In the last few years, Pantoea citrea has been described as the causative agent of pink disease. In this study, over 300 bacterial isolates from pineapple plants, growing in Mexican commercial fields, and from soil close to plant roots were recovered. Over 250 isolates showed a very high similarity in their phenotypic and genotypic traits with Tatumella ptyseos, a close relative of Pantoea. These isolates exhibited typical pathogenicity reactions in pineapple juice tests, pineapple slices and fruit. On this basis, molecular identification procedures for the Tatumella isolates associated with pink disease were implemented. In affected fruit populations around 106 CFU/g of fresh tissue were recovered. This is first time that T. ptyseos is demonstrated as a causal agent of pink disease. 相似文献
992.
Eduardo Quintana Yolima Torres Angela Rojas Marcela Camacho 《Experimental parasitology》2010,124(3):258-264
Understanding the impact of intracellular pathogens on the behavior of their host cells is key to designing new interventions. We are interested in how Leishmania alters the electrical function of the plasma membrane of the macrophage it infects. The specific question addressed here is the impact of Leishmania infection on macrophage membrane properties during the first 12 h post-infection. A decrease of 29% in macrophage membrane capacitance at 3 h post-infection indicates that the phagolysosome membrane is donated on entry by the macrophage plasma membrane. Macrophage membrane potential depolarized during the first 12 h post-infection, which associated with a decreased inward potassium current density, changed in inward rectifier conductance and increased outward potassium current density. Decreased membrane capacitance and membrane potential, with no changes in ion current density, were found in macrophages after phagocytosis of latex beads. Therefore we suggest that the macrophage membrane changes observed during early Leishmania infection appear to be associated with the phagocytic and activation processes. 相似文献
993.
994.
Patrícia Rijo M. Fátima Simões A. Paula Francisco Rosario Rojas Robert H. Gilman Abraham J. Vaisberg Benjamín Rodríguez Cristina Moiteiro 《化学与生物多样性》2010,7(4):922-932
The antimycobacterial activities of eight diterpenes, 1 – 8 , isolated previously from Plectranthus and eleven esters, 9 – 19 , of 7α‐acetoxy‐6β,12‐dihydroxyabieta‐8,12‐diene‐11,14‐dione ( 5 ) were evaluated against the MTB strains H37Rv and MDR. Only diterpenoids with a quinone framework revealed anti‐MTB activity. Abietane 5 and its 6,12‐dibenzoyl, 12‐methoxybenzoyl, 12‐chlorobenzoyl, and 12‐nitrobenzoyl esters, 9, 11, 12 , and 13 , respectively, showed potent activities against the MDR strain with MIC values between 3.12 and 0.39 μg/ml. Cytotoxic activities towards 3T3 and Vero cells were also evaluated. Compound 11 , with the best selectivity index, may be a suitable lead for further chemical modifications. The complete structural elucidation of the new esters, 9 – 14, 16, 18 , and 19 , as well as the NMR data of known derivatives 15 and 17 are reported. 相似文献
995.
Dujardin JC Herrera S do Rosario V Arevalo J Boelaert M Carrasco HJ Correa-Oliveira R Garcia L Gotuzzo E Gyorkos TW Kalergis AM Kouri G Larraga V Lutumba P Macias Garcia MA Manrique-Saide PC Modabber F Nieto A Pluschke G Robello C Rojas de Arias A Rumbo M Santos Preciado JI Sundar S Torres J Torrico F Van der Stuyft P Victoir K Olesen OF 《PLoS neglected tropical diseases》2010,4(10):e780
996.
Biotransformation in Double-Phase Systems: Physiological Responses of Pseudomonas putida DOT-T1E to a Double Phase Made of Aliphatic Alcohols and Biosynthesis of Substituted Catechols 下载免费PDF全文
Antonia Rojas Estrella Duque Andreas Schmid Ana Hurtado Juan-Luis Ramos Ana Segura 《Applied microbiology》2004,70(6):3637-3643
Pseudomonas putida strain DOT-T1E is highly tolerant to organic solvents, with a logPow (the logarithm of the partition coefficient of a solvent in a two-phase water-octanol system of ≥2.5. Solvent tolerant microorganisms can be exploited to develop double-phase (organic solvent and water) biotransformation systems in which toxic substrates or products are kept in the organic phase. We tested P. putida DOT-T1E tolerance to different aliphatic alcohols with a logPow value between 2 and 4, such as decanol, nonanol, and octanol, which are potentially useful in biotransformations in double-phase systems in which compounds with a logPow around 1.5 are produced. P. putida DOT-T1E responds to aliphatic alcohols as the second phase through cis-to-trans isomerization of unsaturated cis fatty acids and through efflux of these aliphatic alcohols via a series of pumps that also extrude aromatic hydrocarbons. These defense mechanisms allow P. putida DOT-T1E to survive well in the presence of high concentrations of the aliphatic alcohols, and growth with nonanol or decanol occurred at a high rate, whereas in the presence of an octanol double-phase growth was compromised. Our results support that the logPow of aliphatic alcohols correlates with their toxic effects, as octanol (logPow = 2.9) has more negative effects in P. putida cells than 1-nonanol (logPow = 3.4) or 1-decanol (logPow = 4). A P. putida DOT-T1E derivative bearing plasmid pWW0-xylE::Km transforms m-xylene (logPow = 3.2) into 3-methylcatechol (logPow = 1.8). The amount of 3-methylcatechol produced in an aliphatic alcohol/water bioreactor was 10- to 20-fold higher than in an aqueous medium, demonstrating the usefulness of double-phase systems for this particular biotransformation. 相似文献
997.
Kelso C Tillott V Rojas JD Furlan RL Padilla G Beck JL 《Archives of biochemistry and biophysics》2008,477(2):348-355
Cosmomycin D (CosD) is an anthracycline that has two trisaccharide chains linked to its ring system. Gel electrophoresis showed that CosD formed stable complexes with plasmid DNA under conditions where daunorubicin (Dn) and doxorubicin (Dx) dissociated to some extent during the experiments. The footprint and stability of CosD complexed with 10- and 16 mer DNA was investigated using several applications of electrospray ionisation mass spectrometry (ESI-MS). ESI-MS binding profiles showed that fewer CosD molecules bound to the sequences than Dn or Dx. In agreement with this, ESI-MS analysis of nuclease digestion products of the complexes showed that CosD protected the DNA to a greater extent than Dn or Dx. In tandem MS experiments, all CosD–DNA complexes were more stable than Dn- and Dx-DNA complexes. These results support that CosD binds more tightly to DNA and exerts a larger footprint than Dn or Dx. ESI-MS investigations of the binding properties of CosD could be carried out rapidly and using only small amounts of sample. 相似文献
998.
Ibarra JR Orozco AD Rojas JA López K Setlow P Yasbin RE Pedraza-Reyes M 《Journal of bacteriology》2008,190(6):2031-2038
Germination and outgrowth are critical steps for returning Bacillus subtilis spores to life. However, oxidative stress due to full hydration of the spore core during germination and activation of metabolism in spore outgrowth may generate oxidative DNA damage that in many species is processed by apurinic/apyrimidinic (AP) endonucleases. B. subtilis spores possess two AP endonucleases, Nfo and ExoA; the outgrowth of spores lacking both of these enzymes was slowed, and the spores had an elevated mutation frequency, suggesting that these enzymes repair DNA lesions induced by oxidative stress during spore germination and outgrowth. Addition of H2O2 also slowed the outgrowth of nfo exoA spores and increased the mutation frequency, and nfo and exoA mutations slowed the outgrowth of spores deficient in either RecA, nucleotide excision repair (NER), or the DNA-protective α/β-type small acid-soluble spore proteins (SASP). These results suggest that α/β-type SASP protect DNA of germinating spores against damage that can be repaired by Nfo and ExoA, which is generated either spontaneously or promoted by addition of H2O2. The contribution of RecA and Nfo/ExoA was similar to but greater than that of NER in repair of DNA damage generated during spore germination and outgrowth. However, nfo and exoA mutations increased the spontaneous mutation frequencies of outgrown spores lacking uvrA or recA to about the same extent, suggesting that DNA lesions generated during spore germination and outgrowth are processed by Nfo/ExoA in combination with NER and/or RecA. These results suggest that Nfo/ExoA, RecA, the NER system, and α/β-type SASP all contribute to the repair of and/or protection against oxidative damage of DNA in germinating and outgrowing spores. 相似文献
999.
The incidence of lung fibrosis increases with age. Aging is associated with modifications in the intracellular and extracellular environment including alteration of the extracellular matrix, imbalance of the redox state, accumulation of senescent cells and potential alteration of the recruitment of bone marrow mesenchymal stem cells. The combination of these senescence-related alterations in the lung and in bone marrow progenitor cells might be responsible of the higher susceptibility to lung fibrosis in elderly individuals. The understanding of these age related changes must be considered in the rationale for the development of therapeutic interventions to control lung injury and fibrosis. 相似文献
1000.
Expression of the rabies virus nucleoprotein in plants at high-levels and evaluation of immune responses in mice 总被引:1,自引:0,他引:1
Perea Arango I Loza Rubio E Rojas Anaya E Olivera Flores T Gonzalez de la Vara L Gómez Lim MA 《Plant cell reports》2008,27(4):677-685
Transgenic plants have been employed successfully as a low-cost system for the production of therapeutically valuable proteins
including antibodies, antigens and hormones. Here, we report expression of a full-length nucleoprotein gene of rabies virus
in transgenic tomato plants. The nucleoprotein was also transiently expressed in Nicotiana benthamiana plants by agroinfiltration. In both cases, the nucleoprotein was expressed at high levels, 1–5% of total soluble protein
in tomato and 45% in N. benthamiana. Previously, only epitopes of the nucleoprotein had been expressed in plants. The presence and expression of the transgene
was verified by PCR, Southern, northern and western blots. Mice were immunized both intraperitoneally (i.p.) and orally with
tomato protein extracts containing the N protein induced the production of antibodies. The antibody titer of mice immunized
i.p., was at least four times higher than that of mice immunized orally. These results were reflected in the challenge experiments
where i.p.-immunized mice were partially protected against a peripheral virus challenge whereas orally immunized mice were
not. This protection was comparable to that obtained in previous experiments employing different expression systems. Work
is in progress to express both G and N proteins in transgenic plants and evaluate protection in mice. 相似文献