RESUMEN
Salt-tolerant proteases with remarkable stability are highly desirable biocatalysts in the salt-fermented food industry. In this study, the undigested autocleavage product of HlyA (halolysin A), a low-salt adapted halolysin from halophilic archaeon Halococcus salifodinae, was investigated. HlyA underwent autocleavage of its C-terminal extension (CTE) at temperatures over 40 °C or NaCl concentrations below 2 M to yield HlyAΔCTE. HlyAΔCTE demonstrated robust stability over a wide range of -20-60 °C, 0.5-4 M NaCl, and pH 6.0-10.0 for at least 72 h. Notably, HlyAΔCTE is the first reported halolysin with such exceptional stability. Compared with HlyA, HlyAΔCTE preferred high temperatures (50-75 °C), low salinities (0.5-2.5 M NaCl), and near-neutral (pH 6.5-8.0) conditions to achieve high activity, consistently with its production conditions. HlyAΔCTE displayed a higher Vmax value against azocasein than HlyA. During fish sauce fermentation, HlyAΔCTE significantly enhanced fish protein hydrolysis, indicating its potential as a robust biocatalyst in the salt-fermented food industry.
Asunto(s)
Fermentación , Alimentos Fermentados , Cloruro de Sodio , Alimentos Fermentados/microbiología , Cloruro de Sodio/química , Estabilidad de Enzimas , Productos Pesqueros/análisis , Concentración de Iones de Hidrógeno , Halococcus/metabolismo , Proteínas Arqueales/metabolismo , Proteínas Arqueales/química , Péptido Hidrolasas/metabolismo , TemperaturaRESUMEN
Four halophilic archaeal strains YCN1T, YCN58T, LT38T, and LT62T were isolated from Yuncheng Salt Lake (Shanxi, China) and Tarim Basin (Xinjiang, China), respectively. Phylogenetic and phylogenomic analyses showed that these four strains tightly cluster with related species of Halobacterium, Natronomonas, Halorientalis, and Halobellus, respectively. The AAI, ANI, and dDDH values between these four strains and their related species of respective genera were lower than the proposed threshold values for species delineation. Strains YCN1T, YCN58T, LT38T, and LT62T could be differentiated from the current species of Halobacterium, Natronomonas, Halorientalis, and Halobellus, respectively, based on the comparison of diverse phenotypic characteristics. The polar lipid profiles of these four strains were closely similar to those of respective relatives within the genera Halobacterium, Natronomonas, Halorientalis, and Halobellus, respectively. The phenotypic, phylogenetic, and genome-based analyses indicated that strains YCN1T, YCN58T, LT38T, and LT62T represent respective novel species within the genera Halobacterium, Natronomonas, Halorentalis, and Halobellus, for which the names Halobacterium yunchengense sp. nov., Natronomonas amylolytica sp. nov., Halorientalis halophila sp. nov., and Halobellus salinisoli sp. nov. are proposed, respectively.
Asunto(s)
Lagos , Filogenia , Lagos/microbiología , Microbiología del Suelo , Halobacterium/genética , Halobacterium/aislamiento & purificación , Genoma Arqueal , Halobacteriaceae/genética , Halobacteriaceae/aislamiento & purificación , Halobacteriaceae/clasificaciónRESUMEN
Four halophilic archaeal strains, BCD28T, BND7T, PSR21T, and PSRA2T, were isolated from coastal and inland saline soil, respectively. The 16S rRNA and rpoB' gene sequence similarities among these four strains and current species of Halomarina were 95.9-96.6% and 86.9-90.3%, respectively. Phylogenetic and phylogenomic analyses revealed that these four strains tightly cluster with the current species of the genus Halomarina. The AAI, ANI, and dDDH values among these four strains and current species of Halomarina were 65.3-68.4%, 75.8-77.7%, and 20.3-22.0%, respectively, clearly below the threshold values for species demarcation. Strains BCD28T, BND7T, PSR21T, and PSRA2T could be differentiated from the current species of Halomarina based on the comparison of diverse phenotypic characteristics. The major polar lipids of these four strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), and four to five glycolipids. Phosphatidylglycerol sulfate (PGS) was only detected in strain BND7T. The phenotypic, phylogenetic, and genome-based analyses suggested that strains BCD28T (= CGMCC 1.18776T = JCM 34908T), BND7T (= CGMCC 1.18778T = JCM 34910T), PSR21T (= CGMCC 1.17027T = JCM 34147T), and PSRA2T (= CGMCC 1.17214T = JCM 34148T) represent four novel species of the genus Halomarina, for which the names Halomarina litorea sp. nov., Halomarina pelagica sp. nov., Halomarina halobia sp. nov., and Halomarina ordinaria sp. nov. are proposed.
Asunto(s)
ADN de Archaea , Filogenia , ARN Ribosómico 16S , Microbiología del Suelo , ARN Ribosómico 16S/genética , ADN de Archaea/genética , ADN de Archaea/química , Halobacteriaceae/clasificación , Halobacteriaceae/genética , Halobacteriaceae/aislamiento & purificación , Composición de Base , Fosfolípidos/análisis , Análisis de Secuencia de ADNRESUMEN
The taxonomic status of some species of Halobellus, Haloferax, Halogranum, and Haloplanus within the family Haloferacaceae was elucidated by phylogenetic, phylogenomic, and comparative genomic analyses. The relative species of each genus should constitute a single species based on the overall genome-related indexes proposed for species demarcation. The cutoff values of AAI (72.1%), ANI (82.2%), and rpoB' gene similarity (90.7%) were proposed to differentiate genera within the family Haloferacaceae. According to these standards, a novel genus related to the genus Halobaculum was proposed to accommodate Halobaculum halophilum Gai3-2 T and Halobaculum salinum NJ-3-1 T. Five halophilic archaeal strains, DT31T, DT55T, DT92T, SYNS20T, and YSMS11T, isolated from a tidal flat and a marine solar saltern in China, were subjected to polyphasic classification. The phenotypic, phylogenetic, phylogenomic, and comparative genomic analyses revealed that strains DT31T (= CGMCC 1.18923 T = JCM 35417 T), DT55T (= CGMCC 1.19048 T = JCM 36147 T), DT92T (= CGMCC 1.19057 T = JCM 36148 T), SYNS20T (= CGMCC 1.62628 T = JCM 36154 T), and YSMS11T (= CGMCC 1.18927 T = JCM 34912 T) represent five novel species of the genus Halobaculum, for which the names, Halobaculum lipolyticum sp. nov., Halobaculum marinum sp. nov., Halobaculum litoreum sp. nov., Halobaculum halobium sp. nov., and Halobaculum limi sp. nov., are proposed.
Asunto(s)
Euryarchaeota , Halobacteriaceae , Filogenia , ADN de Archaea/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Euryarchaeota/genética , China , GlucolípidosRESUMEN
Haloarchaea with the capacity to degrade alkanes is promising to deal with petroleum pollution in hypersaline environments. However, only a limited number of haloarchaeal species are investigated, and their pathway and mechanism for alkane degradation remain unclear. In this study, Halogranum rubrum RO2-11, a haloarchaeal strain, verified the ability to degrade kerosene and hexadecane in 184 g/L NaCl, with 53% and 52% degradation rates after 9 and 4 days, respectively. Genome sequencing and gene annotation indicated that strain RO2-11 possesses a complete potential alkane-degrading pathway, of which alkane hydroxylases may include CYP450, AlmA, and LadA. Transcriptome and metabolome analyses revealed that the upregulation of related genes in TCA cycle, lysine biosynthesis, and acetylation may help improve hexadecane degradation. Additionally, an alternative degrading pathway of hexadecane based on dual-terminal ß-oxidation may occur in strain RO2-11. It is likely to be the first report of alkane degradation by the genus Halogranum, which may be helpful for applications of oil-pollution bioremediation under high-salt conditions.
Asunto(s)
Alcanos , Biodegradación Ambiental , Alcanos/metabolismo , Halobacteriaceae/genética , Halobacteriaceae/metabolismo , MultiómicaRESUMEN
Halophilic archaea of the class Halobacteria are the most salt-requiring prokaryotes within the domain Archaea. In 1997, minimal standards for the description of new taxa in the order Halobacteriales were proposed. From then on, the taxonomy of the class Halobacteria provides an excellent example of how changing concepts on prokaryote taxonomy and the development of new methods were implemented. The last decades have witnessed a rapid expansion of the number of described taxa within the class Halobacteria coinciding with the era of genome sequencing development. The current members of the International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Halobacteria propose these revisions to the recommended minimal standards and encourage the use of advanced technologies in the taxonomic description of members of the Halobacteria. Most previously required and some recommended minimal standards for the description of new taxa in the class Halobacteria were retained in the present revision, but changes have been proposed in line with the new methodologies. In addition to the 16S rRNA gene, the rpoB' gene is an important molecular marker for the identification of members of the Halobacteria. Phylogenomic analysis based on concatenated conserved, single-copy marker genes is required to infer the taxonomic status of new taxa. The overall genome relatedness indexes have proven to be determinative in the classification of the taxa within the class Halobacteria. Average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values should be calculated for rigorous comparison among close relatives.
Asunto(s)
Ácidos Grasos , Halobacteriales , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Ácidos Grasos/química , Técnicas de Tipificación Bacteriana/métodos , ADN Bacteriano/genética , Composición de BaseRESUMEN
The current species of Halosegnis and Salella within the class Halobacteria are closely related based on phylogenetic, phylogenomic, and comparative genomic analyses. The Halosegnis species showed 99.8-100.0% 16S rRNA and 96.6-99.6% rpoB' gene similarities to the Salella species, respectively. Phylogenetic and phylogenomic analyses showed that Salella cibi CBA1133T, the sole species of Salella, formed a single tight cluster with Halosegnis longus F12-1T, then with Halosegnis rubeus F17-44T. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and average amino acid identity (AAI) values between Salella cibi CBA1133T and Halosegnis longus F12-1T were 99.2, 94.2, and 98.6%, respectively, much higher than the thresholds for species demarcation. This genome-based classification revealed that the genus Salella should be merged with Halosegnis, and Salella cibi should be a later heterotypic synonym of Halosegnis longus. Halophilic archaeal strains DT72T, DT80T, DT85T, and DT116T, isolated from the saline soil of a tidal flat in China, were subjected to polyphasic taxonomic characterization. The phenotypic, chemotaxonomic, phylogenetic, and phylogenomic features indicated that strains DT72T (= CGMCC 1.18925T = JCM 35418T), DT80T (= CGMCC 1.18926T = JCM 35419T), DT85T (= CGMCC 1.19049T = JCM 35605T), and DT116T (= CGMCC 1.19045T = JCM 35606T) represent four novel species of the genera Halorussus, Halosegnis and Haloglomus, respectively, for which the names, Halorussus caseinilyticus sp. nov., Halorussus lipolyticus sp. nov., Halosegnis marinus sp. nov., and Haloglomus litoreum sp. nov., are proposed.
Asunto(s)
Halobacteriaceae , Análisis de Secuencia de ADN , Filogenia , ARN Ribosómico 16S/genética , Halobacteriaceae/genética , China , ADN , ADN de Archaea/genética , Ácidos Grasos/química , ADN Bacteriano/genéticaRESUMEN
Histamine, found abundantly in salt-fermented foods, poses a risk of food poisoning. Natronobeatus ordinarius, a halophilic archaeon isolated from a salt lake, displayed a strong histamine degradation ability. Its histamine oxidase (HOD) gene was identified (hodNbs). This is the first report of an archaeal HOD. The HODNbs protein was determined to be a tetramer with a molecular weight of 307 kDa. HODNbs displayed optimum activity at 60-65 °C, 1.5-2.0 M NaCl, and pH 6.5. Notably, within the broad NaCl range between 0.5 and 2.5 M, HODNbs retained above 50% of its maximum activity. HODNbs exhibited good thermal stability, pH stability, and salinity tolerance. HODNbs was able to degrade various biogenic amines. The Vmax of HODNbs for histamine was 0.29 µmol/min/mg, and the Km was 0.56 mM. HODNbs exhibited high efficiency in histamine removal from fish sauce, namely, 100 µg of HODNbs degraded 5.63 mg of histamine (37.9%) in 10 g of fish sauce within 24 h at 50 °C. This study showed that HODNbs with excellent enzymatic properties has promising application potentials to degrade histamine in high-salt foods.
Asunto(s)
Histamina , Oxidorreductasas , Animales , Histamina/metabolismo , Archaea/metabolismo , Cloruro de Sodio , Aminas Biogénicas/metabolismo , Inocuidad de los AlimentosRESUMEN
Two halophilic archaeal strains TS33T and KZCA124 were isolated from two distant salt lakes on the Qinghai-Xizang Plateau, respectively. Culture-independent analysis indicated that these two strains were original inhabitants but low abundant taxa in respective salt lakes. Strains TS33T and KZCA124 were able to grow at 20-60 °C (optimum were 42 and 35 °C, respectively), with 0.9-4.8 M NaCl (optimum were 3.0 and 2.6 M, respectively), with 0-0.7 M MgCl2 (optimum, 0.3 M) and at pH 5.0-9.5 (optimum were pH 7.5 and pH 7, respectively). The 16S rRNA and rpoB' gene similarities between these two strains were 99.7% and 99.4%, and these two similarities among strains TS33T, KZCA124, and existing species of the family Natrialbaceae were 90.6-95.5% and 84.4-89.3%, respectively. Phylogenetic and phylogenomic analyses indicated that strains TS33T and KZCA124 formed an independent branch separated from neighboring genera, Saliphagus, Natronosalvus, and Natronobiforma. The averagenucleotideidentity (ANI), digital DNA-DNAhybridization (dDDH), and average amino acid identity (AAI) values between strains TS33T and KZCA124 were 96.4%, 73.1%, and 96.7%, respectively, higher than the thresholds for species demarcation. The overall genome-related indexes between these two strains and existing species of family Natrialbaceae were 73-77%, 21-25%, and 63-70%, respectively, significantly lower than the species boundary thresholds. Strains TS33T and KZCA124 may represent a novel species of a new genus within the family Natrialbaceae judged by the cutoff value of AAI (≤76%) proposed to differentiate genera within the family Natrialbaceae. The major polar lipids of strains TS33T and KZCA124 were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, sulfated mannosyl glucosyl diether, and sulfated galactosyl mannosyl glucosyl diether. These two strains could be distinguished from the related genera according to differential phenotypic characteristics. These phenotypic, phylogenetic, and genomic analyses revealed that strains TS33T (=KCTC 4310T = MCCC 4K00132T) and KZCA124 (=CGMCC 1.17432 = JCM 34316) represent a novel species of a new genus of the family Natrialbaceae and were named Halomontanus rarus gen. nov., sp. nov.
Asunto(s)
Composición de Base , ADN de Archaea , Lagos , Filogenia , ARN Ribosómico 16S , Análisis de Secuencia de ADN , Lagos/microbiología , ARN Ribosómico 16S/genética , ADN de Archaea/genética , ADN de Archaea/química , China , Cloruro de Sodio/metabolismo , Ácidos Grasos/análisis , Ácidos Grasos/química , Fosfolípidos/análisis , Fosfolípidos/química , Genoma Arqueal , Hibridación de Ácido NucleicoRESUMEN
The genera Haloarcula and Halomicroarcula are the most closely related genera within the family Haloarculaceae (class Halobacteria). The respective 16S rRNA genes of type strains from the genus Haloarcula showed 94.7-96.5% similarities to their homologous genes of type strains from the genus Halomicroarcula. The Haloarcula species showed 89.3-92.8% rpoB' gene similarities to Halomicroarcula species. These similarities were higher than the proposed genus boundary. Phylogenomic analysis revealed that these two genera formed a tight cluster separated from Halomicrobium with high bootstrap confidence. The average amino acid identity (AAI) values among Haloarcula and Halomicroarcula were 70.1-74.5%, higher than the cutoff value (67.0%) to differentiate the genera Haloarcula and Halomicroarcula from Halomicrobium. These results indicated that the genus Halomicroarcula should be merged with Haloarcula. Then, six novel species are described based on strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T isolated from coarse sea salt, marine solar saltern, and salt lake (China). These six strains formed separate clades (90.1-99.3% 16S rRNA and 89.0-94.9% rpoB' gene similarities) and then clustered with current Haloarcula and Halomicroarcula species (89.4-99.1% 16S rRNA and 87.6-95.0% rpoB' gene similarities), as revealed by phylogenetic analyses. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and AAI values among these six strains and current Haloarcula and Halomicroarcula species were 76.2-89.8%, 25.3-46.0%, and 70.3-89.7%, respectively, clearly below the species demarcation threshold. These six strains were distinguished from current Haloarcula and Halomicroarcula species according to differential phenotypic characteristics. Six novel species, Haloarcula halophila sp. nov., Haloarcula litorea sp. nov., Haloarcula rara sp. nov., Haloarcula halobia sp. nov., Haloarcula pelagica sp. nov., and Haloarcula ordinaria sp. nov., are proposed to accommodate strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T, respectively.
Asunto(s)
Haloarcula , Halobacteriaceae , Halobacteriales , Filogenia , ARN Ribosómico 16S/genética , ADN de Archaea/genética , Composición de Base , Análisis de Secuencia de ADN , Ácidos Grasos/química , ADN Bacteriano , Técnicas de Tipificación BacterianaRESUMEN
Two extremely halophilic archaeal strains, GSLN9T and XZYJT29T, were isolated from the saline soil in different regions of western China. Both strains GSLN9T and XZYJT29T have two 16S rRNA genes with similarities of 95.1 and 94.8â%, respectively. Strain GSLN9T was mostly related to the genus Halomicrococcus based on 16S rRNA (showing 91.0-96.0 % identities) and rpoB' genes (showing 92.0â% identity). Strain XZYJT29T showed 92.1-97.6â% (16S rRNA gene) and 91.4-93.1â% (rpoB' gene) sequence similarities to its relatives in the genus Halosimplex, respectively. The polar lipid profile of strain GSLN9T included phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate (PGS), sulphated mannosyl glucosyl diether (S-DGD-1) and sulphated galactosyl mannosyl glucosyl diether (S-TGD-1), mostly similar to that of Halomicrococcus hydrotolerans H22T. PA, PG, PGP-Me, S-DGD-1 (S-DGD-PA), S2-DGD, S-TGD-1 and an unidentified glycolipid were detected in strain XZYJT29T; this polar lipid composition is similar to those of members of the genus Halosimplex. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between these two strains and their relatives of the genera Halomicrococcus and Halosimplex were no more than 82, 27 and 80â%, respectively, much lower than the thresholds for species demarcation. Other phenotypic characterization results indicated that strains GSLN9T and XZYJT29T can be differentiated from the current species of the genera Halomicrococcus and Halosimplex, respectively. These results revealed that strains GSLN9T (=CGMCC 1.15215T=JCM 30842T) and XZYJT29T (=CGMCC 1.15828T=JCM 31853T) represent novel species of Halomicrococcus and Halosimplex, for which the names Halomicrococcus gelatinilyticus sp. nov. and Halosimplex aquaticum sp. nov. are proposed.
Asunto(s)
Halobacteriaceae , Halobacteriales , ARN Ribosómico 16S/genética , Filogenia , Análisis de Secuencia de ADN , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , Composición de Base , Ácidos Grasos/química , Halobacteriaceae/genética , Fosfatidilgliceroles , Suelo , SulfatosRESUMEN
Two novel halophilic archaeal strains (XZGYJ-43T and ZJ1T) were isolated from Mangkang ancient solar saltern (Tibet, PR China) and Zhujiang river inlet (Guangdong, PR China), respectively. The comparison of the 16S rRNA gene sequences revealed that strain XZGYJ-43T is related to the current species of the family Halobacteriaceae (89.2-91.7% similarity) and strain ZJ1T showed 94.7-98.3% similarity to the current species of the genus Haladaptatus. Phylogenetic analyses based on 16S rRNA genes, rpoB' genes and genomes indicated that strain XZGYJ-43T is separate from the related genera, Halocalculus, Salarchaeum and Halarchaeum of the family Halobacteriaceae, and strain ZJ1T tightly clusters with the current species of the genus Haladaptatus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between strain XZGYJ-43T and the current species of the family Halobacteriaceae were 71-75, 20-25 and 59-68â%, and these values between strain ZJ1T and the current species of the genus Haladaptatus were 77-81, 27-32 and 76-82â%, respectively, clearly below the thresholds for prokaryotic species demarcation. These two strains could be distinguished from their relatives according to differential phenotypic characteristics. The major polar lipids of strain XZGYJ-43T were phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), mannosyl glucosyl diether (DGD-1; DGD-PA) and sulphated mannosyl glucosyl diether (S-DGD-1; S-DGD-PA), and those of strain ZJ1T were PA, PG, PGP-Me, DGD-PA, S-DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. Based on phenotypic, phylogenetic and genomic data, strain XZGYJ-43T (=CGMCC 1.13890T=JCM 33735T) represents a novel species of a new genus within the family Halobacteriaceae, and strain ZJ1T (=CGMCC 1.18785T=JCM 34917T) represents a novel species of the genus Haladaptatus, for which the names Halospeciosus flavus gen. nov., sp. nov. and Haladaptatus caseinilyticus sp. nov. are proposed, respectively.
Asunto(s)
Halobacteriaceae , Halobacteriales , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , Composición de Base , Ácidos Grasos/química , Halobacteriaceae/genética , FosfatidilglicerolesRESUMEN
Two halophilic archaeal strains, ZS-10T and GSL13T, were isolated from the Zhoushan marine saltern in Zhejiang, and an inland saline soil from the Tarim Basin, Xinjiang, PR China, respectively. The cells of strain ZS-10T were pleomorphic while those of strain GSL13T were rod-shaped. Both of them stained Gram-negative and formed red-pigmented colonies on agar plates and their cells lysed in distilled water. The optimum growth of strain ZS-10T was observed at 40â°C, 3.4 M NaCl, 0.03 M MgCl2 and pH 7.5, while that of strain GSL13T was at 37â°C, 3.1 M NaCl, 0.5 M MgCl2 and pH 7.5. Phylogenetic and phylogenomic analyses indicated that these two strains were related to Salinigranum and Halohasta, respectively. Strains ZS-10T and GSL13T could be differentiated from the current members of Salinigranum and Halohasta based on the comparison of diverse phenotypic characteristics. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values among strain ZS-10T and current species of Salinigranum were 75.8-78.6â%, 80.6-81.9â% and 24.3-26.1â%, respectively. These values between strain GSL13T and current species of Halohasta were 78.4-80.8â%, 79.8-82.8% and 22.7-25.7â%, respectively, clearly below the threshold values for species demarcation. The polar lipids of strain ZS-10T were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me) and sulphated mannosyl glucosyl diether (S-DGD-1), while those of strain GSL13T were phosphatidic acid, PG, PGP-Me, phosphatidylglycerol sulphate and S-DGD-1. The polar lipid profile of strain GSL13T was identical to those of Halohasta, whereas strain ZS-10T did not contain the minor glycolipids detected in the current Salinigranum species. The phenotypic, phylogenetic and genome-based results suggested that strains ZS-10T (=CGMCC 1.12868T=JCM 30241T) and GSL13T (=CGMCC 1.15214T=JCM 30841T) represent two novel species, for which the names Salinigranum marinum sp. nov. and Halohasta salina sp. nov. are proposed.
Asunto(s)
Euryarchaeota , Halobacteriaceae , Halobacteriales , Cloruro de Sodio/análisis , Filogenia , Ácidos Grasos/química , ADN de Archaea/genética , ARN Ribosómico 16S/genética , Composición de Base , Análisis de Secuencia de ADN , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , China , Glucolípidos/química , Fosfatidilgliceroles/análisisRESUMEN
A single extremely halophilic strain was isolated from salt brine produced when a fresh water lake flooded a large salt mine located beneath the lake. The water that entered this mine contained less than 0.34 M NaCl, but over time, this sealed brine became saturated by Cenozoic age salt (121-125 million-year BCE). The isolated strain requires at least 1.7 M NaCl for survival and grows optimally in 3.1 M NaCl. Therefore, it could not have survived or been present in the waters that flooded this salt mine. The strain grows at a pH range from 6.5 to 9.0 and has a wide tolerance to temperatures from 25 â to at least 60 â. The comparison of 16S rRNA and rpoB' genes revealed that strain 1-13-28T is related to Halorubrum tebenquichense DSM 14210T showing 98.6% and 98.1% similarities, respectively. Phylogenetic analyses based on 16S rRNA, rpoB' genes and 122 concatenated archaeal genes show that the strain 1-13-28T consistently forms a cluster with Halorubrum tebenquichense of the genus Halorubrum. Strain 1-13-28T contained sulfated mannosyl glucosyl diether, and the polar lipid profile was identical to those of most Halorubrum species. Based on the overall combination of physiological, phylogenetic, polar lipids and phylogenomic characteristics, strain 1-13-28T (= ATCC 700083T = CGMCC 1.62627T) represents a newly identified species within the genus Halorubrum for which the name Halorubrum hochsteinianum is proposed.
Asunto(s)
Halorubrum , Cloruro de Sodio , Fosfolípidos , Halorubrum/genética , ARN Ribosómico 16S/genética , Filogenia , Composición de Base , ADN de Archaea/genética , China , Análisis de Secuencia de ADNRESUMEN
Five halophilic archaeal strains (AGai3-5T, KZCA101T, CGA3T, WLHS1T and WLHSJ1T) were isolated from salt lakes and soda lakes in PR China. These strains had low 16S rRNA gene similarities (91.3-96.0â%) to closely related species of the family Natrialbaceae and may represent a new genus of the family. Phylogenetic and phylogenomic analyses revealed that these strains formed a distinct clade, separate from the nearby genera Natronobiforma and Saliphagus. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity (AAI) values among these five strains and the current members of the family Natrialbaceae were 72-90, 20-42 and 62-91â%, respectively, clearly below the threshold values for species demarcation. According to the critical value of AAI (≤76â%) proposed to differentiate genera within the family Natrialbaceae, it was further indicated that these strains represented a novel genus within the family. These strains could be distinguished from the related genera according to differential phenotypic characteristics. The major lipids of these strains were phosphatidic acid (PA), phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, mannosyl glucosyl diether (DGD-PA), sulphated DGD-1 (S-DGD-PA) and sulphated galactosyl mannosyl glucosyl diether. The phenotypic, chemotaxonomic, phylogenetic and phylogenomic features indicated that strains AGai3-5T (=CGMCC 1.16078T=JCM 33549T), KZCA101T (=CGMCC 1.17431T=JCM 35074T), CGA3T (=CGMCC 1.17463T=JCM 34318T), WLHS1T (=CGMCC 1.13780T=JCM 33562T) and WLHSJ1T (=CGMCC 1.13784T=JCM 33563T) represent five novel species of a new genus within the family Natrialbaceae, named Natronosalvus halobius gen. nov., sp. nov., Natronosalvus caseinilyticus sp. nov., Natronosalvus vescus sp. nov., Natronosalvus rutilus sp. nov. and Natronosalvus amylolyticus sp. nov., respectively.
Asunto(s)
Cyprinidae , Euryarchaeota , Halobacteriales , Animales , Lagos , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , ADN Bacteriano/genética , Técnicas de Tipificación Bacteriana , Composición de Base , Ácidos Grasos/química , AminoácidosRESUMEN
Halophilic extracellular proteases offer promising application in various fields. Information on these prominent proteins including the synthesizing organisms, biochemical properties, domain organisation, purification, and application challenges has never been covered in recent reviews. Although extracellular proteases from bacteria pioneered the study of proteases in halophiles, progress is being made in proteases from halophilic archaea. Recent advances in extracellular proteases from archaea revealed that archaeal proteases are more robust and applicable. Extracellular proteases are composed of domains that determine their mechanisms of action. The intriguing domain structure of halophilic extracellular proteases consists of N-terminal domain, catalytic domain, and C-terminal extension. The role of C-terminal domains varies among different organisms. A high diversity of C-terminal domains would endow the proteases with diverse functions. With the development of genomics, culture-independent methods involving heterologous expression, affinity chromatography, and in vitro refolding are deployed with few challenges on purification and presenting novel research opportunities. Halophilic extracellular proteases have demonstrated remarkable potentials in industries such as detergent, leather, peptide synthesis, and biodegradation, with desirable properties and ability to withstand harsh industrial processes. KEY POINTS: ⢠Halophilic extracellular proteases have robust properties suitable for applications. ⢠A high diversity of C-terminal domains may endow proteases with diverse properties. ⢠Novel protease extraction methods present novel application opportunities.
Asunto(s)
Biotecnología , Péptido Hidrolasas , Péptido Hidrolasas/metabolismo , Biotecnología/métodos , Bacterias/metabolismo , Archaea/metabolismo , Endopeptidasas/metabolismoRESUMEN
Four halophilic archaea strains, AD-4T, CGA30T, CGA73T, and WLHSJ27T, were isolated from a salt lake and two soda lakes located in different regions of China. The 16S rRNA and rpoB' gene sequence similarities among strains AD-4T, CGA30T, CGA73T, WLHSJ27T, and the current species of the family Natrialbaceae were 90.9-97.5% and 83.1-91.8%, respectively. The phylogenetic and phylogenomic analyses revealed that these four strains separated from existing genera in the family Natrialbaceae and formed distant branches. The ANI, isDDH, and AAI values among these four strains and the current members of the family Natrialbaceae were 72-79%, 20-25%, and 63-73%, respectively, much lower than the threshold values for species demarcation. Strains AD-4T, CGA73T, and WLHSJ27T may represent three novel genera of the family Natrialbaceae according to the cutoff value of AAI (≤ 76%) proposed to differentiate genera within the family Natrialbaceae. These four strains could be distinguished from the related genera according to differential phenotypic characteristics. The major phospholipids of these four strains were identical while their glycolipid profiles were diverse. DGD-1 is a major glycolipid found in strain AD-4T, trace glycolipids, DGD-1, and S-DGD-1, and (or) S-TGD-1 was found in the other three strains. The major respiratory quinones detected in the four strains were menaquinone MK-8 and MK-8(H2). This polyphasic classification indicated that strains AD-4T, CGA73T, and WLHSJ27T represent three novel species of three new genera with the family Natrialbaceae, and strain CGA30T represents a novel species of Halovivax.
Asunto(s)
Euryarchaeota , Halobacteriaceae , Filogenia , Lagos , ARN Ribosómico 16S/genética , ADN de Archaea/genética , Análisis de Secuencia de ADN , Hibridación de Ácido Nucleico , China , Glucolípidos , Euryarchaeota/genéticaRESUMEN
Currently, there are four mainstream taxonomic opinions on the classification of the class Halobacteria at the family and order levels. The International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Halobacteria (ICSP), List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Centre for Biotechnology Information (NCBI) adopted taxonomies have three to four orders and up to eight families, while the Genome Taxonomy Database (GTDB) taxonomy proposes only one order with nine families. To resolve the taxonomic inconsistency, phylogenomic analyses based on concatenated single-copy orthologous proteins and 122 concatenated conserved single-copy marker proteins were conducted to infer the taxonomic status of the current representatives of the class Halobacteria at the family and order levels. The current 76 genera with validly published names of the class Halobacteria were able to be assigned into eight families in one order. On the basis of these results, it is proposed that the current species with validly published names of the class Halobacteria should be remerged into the order Halobacteriales, then assigned to eight families, Haladaptataceae, Haloarculaceae, Halobacteriaceae, Halococcaceae, Haloferacaceae, Natronoarchaeaceae, Natrialbaceae and Halorubellaceae. Thus, Haladaptataceae fam. nov. is described based on Haladaptatus, Halomicrococcus and Halorussus and Halorubellaceae fam. nov. is proposed incorporating Haloarchaeobius and Halorubellus, respectively.