Project description:To investigate the transcriptional profile of GVE2 genes, the viral genes were identified by DNA microarray with Cy5- or Cy3-dUTP-labeled cDNAs prepared from uninfected and GVE2-infected Geobacillus sp. E263 at 4 h p.i.. After hybridization with the Cy3-dUTP-labeled cDNAs from GVE2-infected Geobacillus sp. E263 at 4 h p.i., Cy5-dUTP-labeled cDNAs from uninfected Geobacillus sp. E263 as well as Cy3- dUTP-labeled yeast cDNAs and Hex DNA, many spots produced positive signals significantly above the background, while no signal appeared for the Cy5-dUTP-labeled cDNAs from uninfected Geobacillus sp. E263., indicating that the positive signals represented the GVE2 gene transcripts detectable by DNA microarray. The DNA fragments, detected to be positive in the reverse transcripts at 4 h p.i., contained 74.2% of the presumptive GVE2 ORFs. Keywords: Transcriptional profile of thermophilic bacteriophage at 4 h p.i.
Project description:To investigate the transcriptional profile of GVE2 genes, the viral genes were identified by DNA microarray with Cy5- or Cy3-dUTP-labeled cDNAs prepared from uninfected and GVE2-infected Geobacillus sp. E263 at 4 h p.i.. After hybridization with the Cy3-dUTP-labeled cDNAs from GVE2-infected Geobacillus sp. E263 at 4 h p.i., Cy5-dUTP-labeled cDNAs from uninfected Geobacillus sp. E263 as well as Cy3- dUTP-labeled yeast cDNAs and Hex DNA, many spots produced positive signals significantly above the background, while no signal appeared for the Cy5-dUTP-labeled cDNAs from uninfected Geobacillus sp. E263., indicating that the positive signals represented the GVE2 gene transcripts detectable by DNA microarray. The DNA fragments, detected to be positive in the reverse transcripts at 4 h p.i., contained 74.2% of the presumptive GVE2 ORFs. Keywords: Transcriptional profile of thermophilic bacteriophage at 4 h p.i. A DNA microarray containing 82 DNA fragments of the viral genome was constructed following a PCR-based microarray method. Briefly, specific primer sets were designed to amplify approximately 500-bp fragment each using viral genome as template. All PCR products showing a single band of the appropriate size by gel electrophoresis were purified, and reconstituted in TE buffer at a final concentration of about 500 μg/ml for spotting in triplicates onto the silylated-glass slides (CEL Associates, Inc. USA) using a microarrayer (Smart Arrayer 48, CapitalBio). Eight DNA fragments from yeast genome and a randomly synthesized DNA fragment (Hex) were included as exogenous positive controls to normalize the microarry date. Distilled water was used as negative controls. Total RNAs were isolated from the uninfected and phage-infected Geobacillus sp. E263 cells at 4 h postinfection. The cDNAs from uninfected Geobacillus sp. E263 were labeled with Cy5 and the cDNAs from phage-infected Geobacillus sp. E263 labeled with Cy3. At the same time, the cDNAs from yeast and the Hex DNA were labeled with Cy3. The Cy5- or Cy3-dUTP-labeled cDNAs were resuspended in hybridization solution and hybridized with the microarrays for 16 to 18 h at 42°C. Then the microarrays were rinsed several times following the standard method. Following the washing steps, the microarrays were dried by low-speed centrifugation (500 g for 5 min), and immediately scanned using a GenePix 4000B array scanner (Axon Instruments, Inc.). Images obtained from scanning were analyzed by GenePix Pro 4.0 array analysis software (Axon Instruments, Inc.)
Project description:In deep-sea hydrothermal vent communities, viruses play very important roles. However vent thermophilic bacteriophages remain largely unexplored. In this investigation, a novel vent Geobacillus bacteriophage, D6E, was characterized. Based on comparative genomics and proteomics analyses, the results showed an extensive mosaicism of D6E genome with other mesophilic or thermophilic phages.
Project description:HNH endonucleases in bacteriophages play a variety of roles in the phage lifecycle as key components of phage DNA packaging machines. The deep-sea thermophilic bacteriophage Geobacillus virus E2 (GVE2) encodes an HNH endonuclease (GVE2 HNHE). Here, the crystal structure of GVE2 HNHE is reported. This is the first structural study of a thermostable HNH endonuclease from a thermophilic bacteriophage. Structural comparison reveals that GVE2 HNHE possesses a typical ???-metal fold and Zn-finger motif similar to those of HNH endonucleases from other bacteriophages, apart from containing an extra ?-helix, suggesting conservation of these enzymes among bacteriophages. Biochemical analysis suggests that the alanine substitutions of the conserved residues (H93, N109 and H118) in the HNH motif of GVE2 HNHE abolished 94%, 60% and 83% of nicking activity, respectively. Compared to the wild type enzyme, the H93A mutant displayed almost the same conformation while the N108A and H118A mutants had different conformations. In addition, the wild type enzyme was more thermostable than the mutants. In the presence of Mn2+ or Zn2+, the wild type enzyme displayed distinct DNA nicking patterns. However, high Mn2+ concentrations were needed for the N109A and H118A mutants to nick DNA while Zn2+ inactivated their nicking activity.
Project description:We observed the expression profile of the total mRNA of wild-type Thermus thermophilus HB8 strain during infection of bacteriophage ϕYS40. Keywords: time course, bacteriophage, infection, wild type
Project description:The virus-host interaction is essential to understanding the role that viruses play in ecological and geochemical processes in deep-sea vent ecosystems. Virus-induced changes in cellular gene expression and host physiology have been studied extensively. However, the molecular mechanism of interaction between a bacteriophage and its host at high temperature remains poorly understood. In the present study, the virus-induced gene expression profile of Geobacillus sp. E263, a thermophile isolated from a deep-sea hydrothermal ecosystem, was characterized. Based on proteomic analysis and random arbitrarily primed PCR (RAP-PCR) of Geobacillus sp. E263 cultured under non-bacteriophage GVE2 infection and GVE2 infection conditions, there were two types of protein/gene profiles in response to GVE2 infection. Twenty differentially expressed genes and proteins were revealed that could be grouped into 3 different categories based on cellular function, suggesting a coordinated response to infection. These differentially expressed genes and proteins were further confirmed by Northern blot analysis. To characterize the host proteins in response to virus infection, aspartate aminotransferase (AST) was inactivated to construct the AST mutant of Geobacillus sp. E263. The results showed that the AST protein was essential in virus infection. Thus, transcriptional and proteomic analyses and functional analysis revealed previously unknown host responses to deep-sea thermophilic virus infection.
Project description:We observed the expression profile of the total mRNA of wild-type Thermus thermophilus HB8 strain during infection of bacteriophage ϕYS40.
Project description:Myceliophthora thermophila is a thermophilic fungus with great biotechnological characteristics for industrial applications, which can degrade and utilize all major polysaccharides in plant biomass. Nowadays, it has been developing into a platform for production of enzyme, commodity chemicals and biofuels. Therefore, an accurate genome-scale metabolic model would be an accelerator for this fungus becoming a universal chassis for biomanufacturing. Here we present a genome-scale metabolic model for M. thermophila constructed using an auto-generating pipeline with consequent thorough manual curation. Temperature plays a basic and critical role for the microbe growth. we are particularly interested in the genome wide response at metabolic layer of M. thermophilia as it is a thermophlic fungus. To study the effects of temperature on metabolic characteristics of M. thermophila growth, the fungus was cultivated under different temperature. The metabolic rearrangement predicted using context-specific GEMs integrating transcriptome data.The developed model provides new insights into thermophilic fungi metabolism and highlights model-driven strain design to improve biotechnological applications of this thermophilic lignocellulosic fungus.