Assembly and Annotation of Red Spruce (Picea rubens) Chloroplast Genome, Identification of Simple Sequence Repeats, and Phylogenetic Analysis in Picea

We have sequenced the chloroplast genome of red spruce (Picea rubens) for the first time using the single-end, short-reads (44 bp) Illumina sequences, assembled and functionally annotated it, and identified simple sequence repeats (SSRs). The contigs were assembled using SOAPdenovo2 following the retrieval of chloroplast genome sequences using the black spruce (Picea mariana) chloroplast genome as the reference. The assembled genome length was 122,115 bp (gaps included). Comparatively, the P. rubens chloroplast genome reported here may be considered a near-complete draft. Global genome alignment and phylogenetic analysis based on the whole chloroplast genome sequences of Picea rubens and 10 other Picea species revealed high sequence synteny and conservation among 11 Picea species and phylogenetic relationships consistent with their known classical interrelationships and published molecular phylogeny. The P. rubens chloroplast genome sequence showed the highest similarity with that of P. mariana and the lowest with that of P. sitchensis. We have annotated 107 genes including 69 protein-coding genes, 28 tRNAs, 4 rRNAs, few pseudogenes, identified 42 SSRs, and successfully designed primers for 26 SSRs. Mononucleotide A/T repeats were the most common followed by dinucleotide AT repeats. A similar pattern of microsatellite repeats occurrence was found in the chloroplast genomes of 11 Picea species

Environmental interactions are regulated by temperature in Burkholderia seminalis TC3.4.2R3.

Burkholderia seminalis strain TC3.4.2R3 is an endophytic bacterium isolated from sugarcane roots that produces antimicrobial compounds, facilitating its ability to act as a biocontrol agent against phytopathogenic bacteria. In this study, we investigated the thermoregulation of B. seminalis TC3.4.2R3 at 28 °C (environmental stimulus) and 37 °C (host-associated stimulus) at the transcriptional and phenotypic levels. The production of biofilms and exopolysaccharides such as capsular polysaccharides and the biocontrol of phytopathogenic fungi were enhanced at 28 °C. At 37 °C, several metabolic pathways were activated, particularly those implicated in energy production, stress responses and the biosynthesis of transporters. Motility, growth and virulence in the Galleria mellonella larvae infection model were more significant at 37 °C. Our data suggest that the regulation of capsule expression could be important in virulence against G. mellonella larvae at 37 °C. In contrast, B. seminalis TC3.4.2R3 failed to cause death in infected BALB/c mice, even at an infective dose of 107 CFU.mL-1. We conclude that temperature drives the regulation of gene expression in B. seminalis during its interactions with the environment

Homologous Gene Finding

Tato diplomová práce se zabývá problematikou homologních genů a popisem molekulárně biologických databází, které slouží k jejich vyhledávání a vzájemnému porovnávání. Mezi nejdůležitější instituce, které se zabývají správou dat a jejich analýzou, patří EBI, NCBI a CIB. Pro vyhledávání homologních genů je nejzásadnější NCBI – Národní centrum pro biotechnologické informace. Bližší pozornost je věnována vyhledávacím algoritmům homologních genů jako jsou například blastn a PatternHunter. Praktická část této diplomové práce je pak realizace algoritmu srovnávajícího dvě sekvence a nacházejícího homologní geny, a to jak na základě sekvence nukleotidů, tak aminokyselin. Výsledky z vytvořeného programu budou dále konfrontovány s výsledky z komerčně dostupných programů.This diploma thesis deals with the description of homologous genes and molecular biological databases that are used for their search and allow comparison. Among the most important institutions that deal with data management and analysis, include the EBI, NCBI and CIB. For searching homologous genes is the most fundamental NCBI - National Center for Biotechnology Information. More attention is paid to the search algorithms of homologous genes such as BLASTN and PatternHunter. The practical part of this thesis is the implementation of the algorithm comparing two sequences and locating homologous genes. The comparison is made on the basis of the nucleotide sequence and amino acid sequence. The results generated from the program will be further compared with results from commercially available programs.

Global Genome Responses to DNA-Repair Deficiency Modulate Aging and Stress Response Pathways

The genomes of all animals are constantly challenged by exogenous and endogenous sources of DNA damaging agents. UV radiation, chemicals, pollutants, and by-products of the cells’ own metabolism may damage the genetic material. Such damages are harmful to the animal as they may cause mutations or generate cytotoxic lesions, which in turn may lead to disease, cancer and aging. Protection of the genome is therefore of the utmost importance. To counteract such potential detrimental effects, all organisms have developed protective mechanisms such as antioxidants and DNA repair mechanisms. DNA excision repair proteins detect lesions in DNA, excise the damaged base and re-insert a correct base, thus maintaining the correct coding properties of the genome. Defects in DNA repair mechanisms may lead to cancer, neurodegeneration, other age-related pathologies or senescence. The nematode Caenorhabditis elegans (C. elegans) contains very few DNA glycosylases, which are the lesion-detecting proteins in DNA excision repair, compared to other animals and organisms. Analysis of all transcribed genes in DNA repair-deficient mutants in C. elegans revealed a global transcriptional response aimed at minimizing further damage to the genome. This involved a down-regulation of insulin-like signaling and an upregulation of antioxidants and stress response genes, similar to the response seen in both long-lived and old animals. This response seems to be conserved across different species as analysis of comparable mutants in the yeast Saccharomyces cerevisiae and mouse showed a similar response. Pathway reconstruction and literature mining suggests that this response is not elicited only by lack of repair per se, but rather from aberrant or attempted processing of lesions by other repair pathways than those normally repairing such lesions. This result in lesions that block the transcription of active genes and signal the transcription of other genes aimed at reducing further damage to DNA. Analysis of C. elegans mutants deficient in two different repair pathways revealed a completely different response with downregulation of Aurora-B and Polo-like kinase 1 signaling networks as well as downregulation of other DNA repair pathways. The mechanism and signaling origin of this response is yet unknown. Gene expression profiling is emerging as a powerful complementary tool to classical genetics and molecular analysis. By taking a systems biology approach, which takes into account the interplay between many pathways, gene expression profiling may aid in the interpretation of observed phenotypes and assist in the generation of new testable hypotheses