Extremophiles最新文献

In this study, Sphingomonas sp. PAMC26617 and Sphingomonas sp. PAMC26621 isolated from rocks of an Arctic lichen, Umbillicaria sp. and Cetraria sp. respectively, were evaluated for their tolerance to abiotic stress of heavy metal(loid)s (HMMs), salt, and osmotic (drought-like) stress at two different temperatures. HMMs resistance protein (CzcC, CzcD, CopB, CopC, CopD, ArsH, and CorC), and osmoprotectant enzymes such as gamma-glutamyl phosphate reductase (ProA), glutamate 5-kinase (ProB), and pyrroline-5-carboxylate reductase (ProC) were identified in both strains during genome analysis. Heavy metal (HM) resistance protein (CorA) was only identified in Sphingomonas sp. PAMC26621. In addition, both strains showed tolerance to CuSO₄·5H₂O (0.1 mM at 15 °C and 0.25 mM at 25 °C), CoCl₂·6H₂O (0.25 mM at 15 °C and 0.1 mM at 25 °C), ZnSO₄·7H₂O (0.1 mM at 15 °C and 25 °C) and Na₂HAsO₄·7H₂O (10 mM at 15 °C and 25 °C), except for Cd(NO₃)₂·4H₂O. Sphingomonas sp. PAMC26617 showed 0.05 mM Cd(NO₃)₂·4H₂O at 15 °C and 0.01 mM at 25 °C and Sphingomonas sp. PAMC26621 showed 0.01 mM Cd(NO₃)₂·4H₂O at 15 °C and 25 °C, respectively. Furthermore, both strains showed tolerance up to 100 mM NaCl and 100 mM D-mannitol at both temperatures. This study is very informative and helpful in understanding the diversity and adaptability of lichen-associated bacteria in harsh environments.

The bacterial phylum Caldisericota has a wide geographical and environmental distribution, but cultivated representatives of this phylum have so far been limited to a single strain. We have isolated a novel anaerobic, thermophilic, fermentative bacterium, strain AR60^T from a thermal spring in Sakhalin Island, Russia. Cells of strain AR60^T were long rods and tended to form aggregates. Growth was observed between 50 and 70 °C (optimum at 60 °C) and between pH 6.0 and 7.5 (optimum pH 6.5). The isolate was capable for fermentative growth on yeast extract, tryptone and peptone. Thiosulfate, S⁰, DMSO stimulated growth. The strain contained iso-C_17:0 as the major fatty acid. Genome size of strain AR60^T was 1.58 Mb; G + C content of the genomic DNA was 34.47%. Phylogenetic analysis revealed that strain AR60^T belongs to the genus Caldisericum of the phylum Caldisericota and has 98.85% identity to C. exile. Based on physiological properties and phylogenetic analyses including an average nucleotide identity values and in silico DNA-DNA hybridization, strain AR60^T is considered as a new species of the genus Caldisericum. We propose to name strain AR60^T (= CGMCC 1.18100^T = VKM B-3836^T) Caldisericum insulae sp. nov. It is the second cultivated representative of the phylum Caldisericota.

Uncultured microorganisms represent a significant portion of the biodiversity of Earth and play crucial roles in ecosystem functioning, particularly in extreme environments. Among these, a novel archaeal lineage, the "OYS group," was recently identified via 16S rRNA gene sequencing from actively boiling hot springs in northeastern Japan. This lineage forms a deep-branching clade, an early-diverging group that is phylogenetically distinct from all the known archaeal phyla. However, no additional reports of the OYS group have emerged from other geothermal environments, raising questions about its ecological niche and geographic distribution. In this study, we conducted a comprehensive 16S rRNA gene-based survey of 17 hot spring sites in Central Kyushu, Japan, covering a broad range of temperatures (30-95 °C) and pH values (4.1-8.8), to assess the distribution and environmental preferences of the OYS group archaea. The OYS group was detected at five high-temperature sites with relative abundances of up to 16.9% and was particularly dominant in the Tsuetate hot spring. Phylogenetic analyses confirmed that these sequences formed a monophyletic clade, a single origin group with the previously reported OYS group sequences. Multivariate analyses revealed co-occurrence with other thermophilic taxa, indicating a possible preference for high-temperature niches. These findings expand the known habitat range of the OYS group and highlight their potential ecological significance in geothermal ecosystems.

Polycyclic aromatic hydrocarbons (PAH) are prevalent environmental contaminants, which exhibit the mutagenic, carcinogenic, and teratogenic properties. The growing demand for efficient PAH biodegradation (BD), particularly in wastewater treatment. This research investigates hydrocarbon degradation using Vreelandella piezotolerant DM1 across a various pH levels (4, 6, 7, 8, and 10) and its enzymatic capabilities. The study assessed the degradation potential of anthracene and phenanthrene under varying PAH concentrations and pH conditions. Optimal bacterial growth and degradation were observed at 300 mg/L of both anthracene and phenanthrene at pH 8. To elucidate the degradation mechanisms, crucial intermediates were identified using gas chromatography mass-spectrometry (GC-MS). The hydrocarbon breakdown intermediates including anthracene-cis-1,2-dihydrodiol, (3Z)-4-[3-hydroxy(2-naphthyl)]-2-oxobut-3-enoic acid, 6,7-benzocoumarin, 1-hydroxy-2-naphthaldehyde, phenanthrene-cis-1,2-dihydrodiol, 1-hydroxy-2-naphthoic acid, and salicylic acid were observed during BD. Both intermediate compounds were conformed the salicylic acid pathway. GC-MS confirms the efficient degradation rates of 62% for anthracene, 82% for phenanthrene, and 83% for mixed hydrocarbons. These observations confirm that optimal conditions are obligatory for the enzymatic activity of the DM1 and a biodegradation pathway was proposed on the identified intermediates. In conculsion, V. piezotolerant DM1 serves as a potential candidate for hydrocarbon degradation in contaminated environment.

L-Asparaginase (L-ASNase) is a chemotherapy drug that has been used as a therapy for the treatment of some types of cancer, including leukemia and lymphoma. Its action involves inhibiting the growth of tumor cells by reducing the availability of asparagine in the body. L-ASNase is an enzyme produced by microorganisms; however, they have adverse effects, which may be related to the activities of glutaminase and urease. Bioprospecting in cold environments, such as the Antarctic continent, may be a promising alternative in the search for enzymes with differentiated properties. For these reasons, the present study evaluated the production of glutaminase- and urease-free L-asparaginase by fungi isolated from soil and wood collected on two islands of the South Shetland Archipelago, Antarctica. A total of 39 filamentous fungi were recovered. Mortierella turficola FM2.1, isolated from wood, produced only L-asparaginase in a solid culture medium assay, showing an enzymatic index of 2.83. The effects of enzymatic extracts on HBMEC, MRC-5, and MIAPaCa-2 cell lines were investigated. MTT assay showed IC₅₀ lower than that of the control, especially in the carcinogenic MIAPaCa-2 cell line. Fluorescence analysis of MIA PaCa-2 showed deformations in the cytoskeleton and nucleus of cells treated with enzymatic extracts up to 50%, in addition to a reduction in cell quantity. These results suggest that L-ASNase produced by the FM2.1 strain may have potential application in the treatment of pancreatic cancer. However, cytotoxic action has been observed in non-tumor cells. Future studies on the characterization of L-ASNase from enzymatic extracts for biotechnological applications should be conducted, aiming for trials with fewer side effects.