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151.
152.
The domestic dog could be a valuable model for studying and developing assisted reproduction in taxonomically related endangered Canids. However, the efficiency of in vitro oocyte maturation is very low in this species compared to that of other mammalian species and this limits the development of reproductive biotechnologies, such as in vitro embryo production, cryopreservation, or nucleus transfer. In canine species the female gamete has unique characteristics: the oocyte is exposed to high concentration of progesterone in the follicular environment, it is ovulated in the dictyate state, and resumes and completes meiosis in the oviduct. Therefore, optimum conditions for in vitro maturation of dog oocytes may differ from other mammalian models in which follicles, where estrogens are the dominant hormones, ovulate oocytes at the Metaphase II stage of the first meiotic division. An in vitro culture system needs to be based on in vivo conditions in order to create a microenvironment similar to that in which oocyte development occurs physiologically, but little is known on mechanisms regulating oocyte maturation in the dog. This review analyzes the known factors involved in canine oocyte maturation in vivo and in vitro in order to suggest on which aspects future investigations may be focused. 相似文献
153.
Foguel D 《Protein and peptide letters》2005,12(3):245-249
High hydrostatic pressure (HHP) is a powerful tool to study protein folding and the dynamics and structure of folding intermediates. Aggregates and amyloids, derived from partially folding intermediates at the junction between productive and off-pathway folding, have been studied as well, which promises better understanding of the protein misfolding diseases. Here is summarized the recent data we have collected with transthyretin under pressure. 相似文献
154.
DNA converts cellular prion protein into the beta-sheet conformation and inhibits prion peptide aggregation 总被引:7,自引:0,他引:7
Cordeiro Y Machado F Juliano L Juliano MA Brentani RR Foguel D Silva JL 《The Journal of biological chemistry》2001,276(52):49400-49409
The main hypothesis for prion diseases proposes that the cellular protein (PrP(C)) can be altered into a misfolded, beta-sheet-rich isoform (PrP(Sc)), which in most cases undergoes aggregation. In an organism infected with PrP(Sc), PrP(C) is converted into the beta-sheet form, generating more PrP(Sc). We find that sequence-specific DNA binding to recombinant murine prion protein (mPrP-(23-231)) converts it from an alpha-helical conformation (cellular isoform) into a soluble, beta-sheet isoform similar to that found in the fibrillar state. The recombinant murine prion protein and prion domains bind with high affinity to DNA sequences. Several double-stranded DNA sequences in molar excess above 2:1 (pH 4.0) or 0.5:1 (pH 5.0) completely inhibit aggregation of prion peptides, as measured by light scattering, fluorescence, and circular dichroism spectroscopy. However, at a high concentration, fibers (or peptide aggregates) can rescue the peptide bound to the DNA, converting it to the aggregating form. Our results indicate that a macromolecular complex of prion-DNA may act as an intermediate for the formation of the growing fiber. We propose that host nucleic acid may modulate the delicate balance between the cellular and the misfolded conformations by reducing the protein mobility and by making the protein-protein interactions more likely. In our model, the infectious material would act as a seed to rescue the protein bound to nucleic acid. Accordingly, DNA would act on the one hand as a guardian of the Sc conformation, preventing its propagation, but on the other hand may catalyze Sc conversion and aggregation if a threshold level is exceeded. 相似文献
155.
156.
Bakker PA Glandorf DC Viebahn M Ouwens TW Smit E Leeflang P Wernars K Thomashow LS Thomas-Oates JE van Loon LC 《Antonie van Leeuwenhoek》2002,81(1-4):617-624
Pseudomonas putida WCS358r, genetically modified to have improved activity against soil-borne pathogens, was released into the rhizosphere of
wheat. Two genetically modified derivatives carried the phzor the phl biosynthetic gene loci and constitutively produced either the antifungal compound phenazine-1-carboxylic acid (PCA) or the
antifungal and antibacterial compound 2,4-diacetylphloroglucinol (DAPG). In 1997 and 1998, effects of single introductions
of PCA producing derivatives on the indigenous microflora were studied. A transient shift in the composition of the total
fungal microflora, determined by amplified ribosomal DNA restiction analysis (ARDRA), was detected. Starting in 1999, effects
of repeated introduction of genetically modified microorganisms (GMMs) were studied. Wheat seeds coated with the PCA producer,
the DAPG producer, a mixture of the PCA and DAPG producers, or WCS358r, were sown and the densities, composition and activities
of the rhizosphere microbial populations were measured. All introduced strains decreased from 107CFU per gram of rhizosphere sample to below the detection limit after harvest of the wheat plants. The phz genes were stably maintained in the PCA producers, and PCA was detected in rhizosphere extracts of plants treated with this
strain or with the mixture of the PCA and DAPG producers. The phl genes were also stably maintained in the DAPG producing derivative of WCS358r. Effects of the genetically modified bacteria
on the rhizosphere fungi and bacteria were analyzed by using amplified ribosomal DNA restriction analysis. Introduction of
the genetically modified bacterial strains caused a transient change in the composition of the rhizosphere microflora. However,
introduction of the GMMs did not affect the several soil microbial activities that were investigated in this study.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
157.
Falasca Antonio Melck Dominique Paris Debora Saviano Gabriella Motta Andrea Iorizzi Maria 《Metabolomics : Official journal of the Metabolomic Society》2014,10(1):165-174
Metabolomics - The economically important crop Juniperus communis (Cupressaceae) is a coniferous evergreen shrub or tree distributed throughout the temperate zone of the Northern hemisphere. Its... 相似文献
158.
Suelen Silva Gomes Dias Vinicius Cardoso Soares Andr C. Ferreira Carolina Q. Sacramento Natalia Fintelman-Rodrigues Jairo R. Temerozo Lívia Teixeira Marcos Alexandre Nunes da Silva Ester Barreto Mayara Mattos Caroline S. de Freitas Isaclaudia G. Azevedo-Quintanilha Pedro Paulo A. Manso Milene D. Miranda Marilda Mendona Siqueira Eugenio D. Hottz Camila R. R. Po Dumith C. Bou-Habib Debora F. Barreto-Vieira Fernando A. Bozza Thiago M. L. Souza Patricia T. Bozza 《PLoS pathogens》2020,16(12)
Viruses are obligate intracellular parasites that make use of the host metabolic machineries to meet their biosynthetic needs. Thus, identifying the host pathways essential for the virus replication may lead to potential targets for therapeutic intervention. The mechanisms and pathways explored by SARS-CoV-2 to support its replication within host cells are not fully known. Lipid droplets (LD) are organelles with major functions in lipid metabolism, energy homeostasis and intracellular transport, and have multiple roles in infections and inflammation. Here we described that monocytes from COVID-19 patients have an increased LD accumulation compared to SARS-CoV-2 negative donors. In vitro, SARS-CoV-2 infection were seen to modulate pathways of lipid synthesis and uptake as monitored by testing for CD36, SREBP-1, PPARγ, and DGAT-1 expression in monocytes and triggered LD formation in different human cell lines. LDs were found in close apposition with SARS-CoV-2 proteins and double-stranded (ds)-RNA in infected Vero cells. Electron microscopy (EM) analysis of SARS-CoV-2 infected Vero cells show viral particles colocalizing with LDs, suggestive that LDs might serve as an assembly platform. Pharmacological modulation of LD formation by inhibition of DGAT-1 with A922500 significantly inhibited SARS-CoV-2 replication as well as reduced production of mediators pro-inflammatory response. Taken together, we demonstrate the essential role of lipid metabolic reprograming and LD formation in SARS-CoV-2 replication and pathogenesis, opening new opportunities for therapeutic strategies to COVID-19. 相似文献
159.
Debora B. Lima José Wagner S. Melo Nelsa Maria P. Guedes Lessando M. Gontijo Raul Narciso C. Guedes Manoel Guedes C. Gondim Jr. 《PloS one》2015,10(2)
Synthetic pesticide use has been the dominant form of pest control since the 1940s. However, biopesticides are emerging as sustainable pest control alternatives, with prevailing use in organic agricultural production systems. Foremost among botanical biopesticides is the limonoid azadirachtin, whose perceived environmental safety has come under debate and scrutiny in recent years. Coconut production, particularly organic coconut production, is one of the agricultural systems in which azadirachtin is used as a primary method of pest control for the management of the invasive coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae). The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae). Here, we assessed the potential behavioral impacts of azadirachtin on the coconut mite predator, N. baraki. We explored the effects of this biopesticide on overall predator activity, female searching time, and mating behavior and fecundity. Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected. In contrast, mating behavior was compromised by azadirachtin exposure particularly when male predators were exposed to the biopesticide. Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents. 相似文献
160.
Debora B. Mello Isalira P. Ramos Fernanda C. P. Mesquita Guilherme V. Brasil Nazareth N. Rocha Christina M. Takiya Ana Paula C. A. Lima Antonio C. Campos de Carvalho Regina S. Goldenberg Adriana B. Carvalho 《PLoS neglected tropical diseases》2015,9(8)