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1.
Front Microbiol ; 12: 737641, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34659168

RESUMO

Species of genus Shewanella are among the most frequently identified psychrotrophic bacteria. Here, we have studied the cellular properties, growth dynamics, and stress conditions of cold-active Shewanella strain #4, which was previously isolated from Baltic Sea ice. The cells are rod-shaped of ~2µm in length and 0.5µm in diameter, and they grow between 0 and 25°C, with an optimum at 15°C. The bacterium grows at a wide range of conditions, including 0.5-5.5% w/v NaCl (optimum 0.5-2% w/v NaCl), pH 5.5-10 (optimum pH 7.0), and up to 1mM hydrogen peroxide. In keeping with its adaptation to cold habitats, some polyunsaturated fatty acids, such as stearidonic acid (18:4n-3), eicosatetraenoic acid (20:4n-3), and eicosapentaenoic acid (20:5n-3), are produced at a higher level at low temperature. The genome is 4,456kb in size and has a GC content of 41.12%. Uniquely, strain #4 possesses genes for sialic acid metabolism and utilizes N-acetyl neuraminic acid as a carbon source. Interestingly, it also encodes for cytochrome c3 genes, which are known to facilitate environmental adaptation, including elevated temperatures and exposure to UV radiation. Phylogenetic analysis based on a consensus sequence of the seven 16S rRNA genes indicated that strain #4 belongs to genus Shewanella, closely associated with Shewanella aestuarii with a ~97% similarity, but with a low DNA-DNA hybridization (DDH) level of ~21%. However, average nucleotide identity (ANI) analysis defines strain #4 as a separate Shewanella species (ANI score=76). Further phylogenetic analysis based on the 92 most conserved genes places Shewanella strain #4 into a distinct phylogenetic clade with other cold-active marine Shewanella species. Considering the phylogenetic, phenotypic, and molecular characterization, we conclude that Shewanella strain #4 is a novel species and name it Shewanella glacialimarina sp. nov. TZS-4T, where glacialimarina means sea ice. Consequently, S. glacialimarina TZS-4T constitutes a promising model for studying transcriptional and translational regulation of cold-active metabolism.

2.
Cell Death Dis ; 12(2): 167, 2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33579905

RESUMO

Multiple myeloma (MM) is a heterogeneous haematological disease that remains clinically challenging. Increased activity of the epigenetic silencer EZH2 is a common feature in patients with poor prognosis. Previous findings have demonstrated that metabolic profiles can be sensitive markers for response to treatment in cancer. While EZH2 inhibition (EZH2i) has proven efficient in inducing cell death in a number of human MM cell lines, we hereby identified a subset of cell lines that despite a global loss of H3K27me3, remains viable after EZH2i. By coupling liquid chromatography-mass spectrometry with gene and miRNA expression profiling, we found that sensitivity to EZH2i correlated with distinct metabolic signatures resulting from a dysregulation of genes involved in methionine cycling. Specifically, EZH2i resulted in a miRNA-mediated downregulation of methionine cycling-associated genes in responsive cells. This induced metabolite accumulation and DNA damage, leading to G2 arrest and apoptosis. Altogether, we unveiled that sensitivity to EZH2i in human MM cell lines is associated with a specific metabolic and gene expression profile post-treatment.


Assuntos
Antineoplásicos/farmacologia , Metilação de DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Metaboloma , Metionina/metabolismo , Mieloma Múltiplo/tratamento farmacológico , Piridonas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Dano ao DNA , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Feminino , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , MicroRNAs/metabolismo , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Transcriptoma
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