Navegando por Palavras-chave "heat shock"

Agora exibindo 1 - 3 de 3
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Conservation of genetic linkage between heat shock protein 100 and glycosylphosphatidylinositol-specific phospholipase C in Trypanosoma brucei and Trypanosoma cruzi
    (Elsevier B.V., 1998-07-01) Redpath, M. B.; Carnall, N.; Webb, H.; Courel, M.; Amorim, A.; Guther, MLS; Almeida, MLC de; Carrington, M.; Univ Cambridge; Universidade Federal de São Paulo (UNIFESP); Univ Dundee
    The experiments described in this paper were designed to try and isolate a recombinant DNA clone encoding a Trypanosoma cruzi homologue of the Trypanosoma br brucei glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) gene. Despite the ready biochemical detection of phospholipase C activities that hydrolyse GPI-anchors of cell surface proteins in T. cruzi, it did not prove possible to isolate any recombinant DNA clones using the T. brucei gpi-plc gene as a probe. On determining the DNA sequence to the 5' side of the gpi-plc gene it was found to be adjacent to a gene that encodes a 100 kDa heat shock protein (HSP100). To investigate whether this linkage between the hsp100 and gpi-plc genes was conserved in T. cruzi, a probe derived from the T. brucei hsp100 gene was used to isolate T. cruzi genomic clones. These were partially sequenced and shown to contain an hsp100 gene. Restriction enzyme fragments located to the 3' side of the T. cruzi hsp100 gene were then sequenced and found to contain a gene that encodes a polypeptide (TcPLC1) that has 46% amino acid sequence identity with the T. brucei GPI-PLC including most of the key residues involved in inositol binding and the catalytic histidine. A recombinant form of TcPLC1 was produced and shown to possess phospholipase C activity towards a GPI-substrate. Thus, the hsp100 and gpi-plc genes are adjacent in T. brucei and this linkage is conserved in T. cruzi. This observation has been used to facilitate the isolation of a clone encoding a T. cruzi phospholipase C gene. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
  • Imagem de Miniatura
    Item
    Acesso aberto (Open Access)
    Evidence for Mitochondrial Genome Methylation in the Yeast Candida albicans: A Potential Novel Epigenetic Mechanism Affecting Adaptation and Pathogenicity?
    (Frontiers Media Sa, 2018) Bartelli, Thais Fernanda [UNIFESP]; Bruno, Danielle C. F.; Briones, Marcelo Ribeiro da Silva [UNIFESP]
    The commensal yeast Candida albicans is an opportunistic pathogen. In order to successfully colonize or infect the human body, the fungus must adapt to the host's environmental conditions, such as low oxygen tension (hypoxia), temperature (37 degrees C), and the different carbon sources available. Previous studies demonstrated the adaptive importance of C. albicans genetic variability for its pathogenicity, although the contributions of epigenetic and the influence of environmental factors are not fully understood. Mitochondria play important roles in fungal energetic metabolism, regulation of nuclear epigenetic mechanisms and pathogenicity. However, the specific impact of inter-strain mitochondrial genome variability and mitochondrial epigenetics in pathogenicity is unclear. Here, we draw attention to this relevant organelle and its potential role in C. albicans pathogenicity and provide preliminary evidence, for the first time, for methylation of the yeast mitochondrial genome. Our results indicate that environmental conditions, such as continuous exposure for 12 weeks to hypoxia and 37 degrees C, decrease the mitochondrial genome methylation in strains SC5314 and L757. However, the methylation decrease is quantitatively different in specific genome positions when strains SC5314 and L757 are compared. We hypothesize that this phenomenon can be promising for future research to understand how physical factors of the host affect the C. albicans mitochondrial genome and its possible impact on adaptation and pathogenicity.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Identification of transcription elements in the 5 ' intergenic region shared by LON and MDJ1 heat shock genes from the human pathogen Paracoccidioides brasiliensis. Evaluation of gene expression
    (Elsevier B.V., 2007-05-01) Batista, Wagner L.; Barros, Tania F.; Goldman, Gustavo H.; Morais, Flavia V.; Puccia, Rosana; Universidade Federal de São Paulo (UNIFESP); Universidade Federal da Bahia (UFBA); Universidade de São Paulo (USP); Univ Vale Paraiba
    The MDJ1ILON locus is conserved among pathogenic dimorphic fungi. We have mapped using DNase I footprinting and mobility shift assays three putative heat shock elements and one AP-1 binding domain (ARE) in the 5' intergenic region shared by PbMDJ1 and PbLON (ML) from Paracoccidioides brasiliensis. the region bearing an ARE-like towards PbLON also has an opposite skn-1-like element. We studied genetically and pathogenically distinct isolates Pb18 and Pb3, where ML is polymorphic and the number of elements detected was higher. the functionality of the elements was suggested by the stimulatory response of both genes to beat shock and oxidative stress. Co-regulation occurred upon heat shock from 36 to 42 degrees C and, only in Pb3, also during mycelium to yeast transformation (26-36 degrees C). in Pb18, PbMDJ1 seemed to be preferentially expressed in yeast. Our study might help understand regulation of genes involved in fungal adaptation to the host. (c) 2006 Elsevier Inc. All rights reserved.