Flagellimonas halotolerans sp. nov., a novel bacterium isolated from the South China Sea.

Two Gram-stain-negative strains, designed SYSU M86414T and SYSU M84420, were isolated from marine sediment samples of the South China Sea (Sansha City, Hainan Province, PR China). These strains were aerobic and could grow at pH 6.0-8.0 (optimum, pH 7.0), 4-37 °C (optimum, 28 °C), and in the presence of 0-10 % NaCl (w/v; optimum 3 %). The predominant respiratory menaquinone of strains SYSU M86414T and SYSU M84420 was MK-6. The primary cellular polar lipid was phosphatidylethanolamine. The major cellular fatty acids (>10 %) in both strains were iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. The DNA G+C content of strains SYSU M86414T and SYSU M84420 were both 42.10 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that these novel strains belonged to the genus Flagellimonas and strain SYSU M86414T showed the highest 16S rRNA gene sequence similarity to Flagellimonas marinaquae JCM 11811T (98.83 %), followed by Flagellimonas aurea BC31-1-A7T (98.62 %), while strain SYSU M84420 had highest 16S rRNA gene sequence similarity to F. marinaquae JCM 11811T (98.76 %) and F. aurea BC31-1-A7T (98.55 %). Based on the results of polyphasic analyses, strains SYSU M86414T and SYSU M84420 should be considered to represent a novel species of the genus Flagellimonas, for which the name Flagellimonas halotolerans sp. nov. is proposed. The type strain of the proposed novel isolate is SYSU M86414T (=GDMCC 1.3806T=KCTC 102040T).

Flavobacterium adhaerens sp. nov. and Flavobacterium maritimum sp. nov., two novel flavobacteria isolated from the Pearl River Estuary.

Two strains, designated as SYSU M80004T and SYSU M80005T, were isolated from water sampled in the Pearl River Estuary, Guangzhou, Guangdong, PR China. The strains were Gram-stain-negative and aerobic. Strain SYSU M80004T could grow at pH 6.0-8.0 (optimum, pH 7.0), 22-30 °C (optimum, 28 °C) and in the presence of 0-1 % NaCl (w/v; optimum 0 %). Strain SYSU M80005T could grow at pH 6.0-8.0 (optimum, pH 7.0), 4-37 °C (optimum, 28 °C) and in the presence of 0-1 % NaCl (w/v; optimum 0%). Both strains contained MK-6 as the predominant menaquinone. C16 : 0 and iso-C15 : 0 were identified as the major fatty acids (>10 %) of strain SYSU M80004T while strain SYSU M80005T contained iso-C15 : 0 and iso-C17 : 0 3-OH as major fatty acids. Phosphatidylethanolamine was present as the major polar lipid in both strains. The average nucleotide identity and digital DNA-DNA hybridization values between these two strains and their closest relatives were 73.5-79.3 % and 19.6-23.2 %, respectively. Phylogenetic analysis based on the 16S rRNA gene and genomic sequences indicated they belonged to the genus Flavobacterium. Therefore, on the basis of phenotypic, physiological, chemotaxonomic and genomic evidence, two novel species, Flavobacterium adhaerens sp. nov. (type strain=SYSU M80004T=CDMCC 1.4522T=KCTC 102268T) and Flavobacterium maritimum sp. nov. (type strain=SYSU M80005T=CGMCC 1.4523T= KCTC 102269T) are proposed.

Ectobacillus ponti sp. nov., a novel bacterium isolated from Pearl River Estuary.

A Gram-staining-positive, aerobic, motile, and rod-shaped strain, designated SYSU M60031T, was isolated from a Pearl River Estuary sediment sample, Guangzhou, Guangdong, China. The isolate could grow at pH 5.0-8.0 (optimum, pH 7.0), 25-37 °C (optimum, 28 °C) and in the presence of 0-1 % (w/v) NaCl (optimum, 0 %). The predominant respiratory menaquinone of SYSU M60031T was MK-7. The cellular polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid, and one unidentified aminolipid. The major fatty acids (>10 % of total) were iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, and C16 : 0. The genomic DNA G+C content was 51.2 %. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M60031T belonged to the genus Ectobacillus and showed the highest sequence similarity to Ectobacillus funiculus NAF001T (96.16%), followed by Ectobacillus antri SYSU K30001T (95.08 %). Based on the phenotypic, genotypic, and phylogenetic data, strain SYSU M60031T should be considered to represent a novel species of the genus Ectobacillus, for which the name Ectobacillus ponti sp. nov. is proposed. The type strain of the proposed novel isolate is SYSU M60031T (=CGMCC 1.19243T =NBRC 115614T).

Cereibacter flavus sp. nov., a novel member of the family Rhodobacteraceae isolated from seawater of the South China Sea and reclassification of Rhodobacter alkalitolerans as Cereibacter alkalitolerans comb. nov.

A Gram-stain-negative, aerobic, motile, ovoid-shaped and yellow-coloured strain, designated SYSU M79828T, was isolated from seawater collected from the South China Sea. Growth of this strain was observed at 4-37 °C (optimum, 28 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-6% NaCl (optimum, 3.0 %, w/v). The respiratory quinone was found to be Q-10. Major fatty acid constituents were C18 : 1 ω7c/C18 : 1 ω6c, C18 : 1 ω7c11-methyl and C18 : 0 (>5 % of total). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphoglycolipid, two unidentified phospholipid, one unidentified lipid and an unidentified glycolipid. The genomic DNA G+C content was 64.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M79828T belonged to the genus Cereibacter and had the highest sequences similarity to 'Rhodobacter xinxiangensis' TJ48T (98.41 %). Based on 16S rRNA gene phylogeny, physiological and chemotaxonomic characterizations, we consider that strain SYSU M79828T represents a novel species of the genus Cereibacter, for which the name Cereibacter flavus sp. nov. is proposed. The type strain is SYSU M79828T (=GDMCC 1.3803T=KCTC 92893T). In addition, according to the results of phylogenetic analysis and similar taxonomic characteristics, we propose that Rhodobacter alkalitolerans should be reclassified as Cereibacter alkalitolerans comb. nov.

Characterization of a reassortant H11N9 subtype avian influenza virus isolated from spot-billed duck in China.

H11N9 viruses in wild birds might have provided the NA gene of human H7N9 virus in early 2013 in China, which evolved with highly pathogenic strains in 2017 and caused severe fatalities. To investigate the prevalence and evolution of the H11N9 influenza viruses, 16,781 samples were collected and analyzed during 2016-2020. As a result, a novel strain of influenza A (H11N9) virus with several characteristics that increase virulence was isolated. This strain had reduced pathogenicity in chicken and mice and was able to replicate in mice without prior adaptation. Phylogenetic analyses showed that it was a sextuple-reassortant virus of H11N9, H3N8, H3N6, H7N9, H9N2, and H6N8 viruses present in China, similar to the H11N9 strains in Japan and Korea during the same period. This was the H11N9 strain isolated from China most recently, which add a record to viruses in wild birds. This study identified a new H11N9 reassortant in a wild bird with key mutation contributing to virulence. Therefore, comprehensive surveillance and enhanced biosecurity precautions are particularly important for the prediction and prevention of potential pandemics resulting from reassortant viruses with continuous evolution and expanding geographic distributions.

Alsobacter ponti sp. nov., a novel denitrification and sulfate reduction bacterium isolated from Pearl River sediment.

A Gram-staining negative, aerobic, motile, and short rods strain, designated SYSU M60028T, was isolated from a Pearl River sediment sample in Guangzhou, Guangdong, China. The isolate could be able to grow at pH 6.0-8.0 (optimum, pH 7.0), 25-37 °C (optimum, 28 °C) and in the presence of 0-2% (w/v) NaCl (optimum, 0% NaCl). The cellular polar lipids of this strain were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, one unidentified aminolipid and three unidentified lipids. The respiratory quinone of SYSU M60028T was found to be Q-10. The major fatty acids (> 5% of total) were summed feature 8, C16:0, and C18:1 ω7c 11-methy1. The genomic DNA G + C content was 69.9%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M60028T belonged to the genus Alsobacter and had the highest sequences similarities to Alsobacter metallidurans SK200a-9T (96.87%) and Alsobacter soli SH9T (96.87%). Based on the phenotypic, genotypic, and phylogenetic data, strain SYSU M0028T should be considered to represent a novel species of the genus Alsobacter, for which the name Alsobacter ponti sp. nov. is proposed. The type strain is SYSU M60028T (= CGMCC 1.19341T = KCTC 92046T).

Novel Steroidal[17,16-d]pyrimidines Derived from Epiandrosterone and Androsterone: Synthesis, Characterization and Configuration-Activity Relationships.

Two series of novel steroidal[17,16-d]pyrimidines derived from natural epiandrosterone and androsterone were designed and synthesized, and these compounds were screened for their potential anticancer activities. The preliminary bioassay indicated that some of these prepared compounds exhibited significantly good cytotoxic activities against human gastric cancer (SGC-7901), lung cancer (A549), and hepatocellular liver carcinoma (HepG2) cell lines compared with 5-fluorouracil (5-FU), epiandrosterone, and androsterone. Especially the respective pairs from epiandrosterone and androsterone showed significantly different inhibitory activities, and the possible configuration-activity relationships have also been summarized and discussed based on kinase assay and molecular docking, which indicated that the inhibition activities of these steroidal[17,16-d]pyrimidines might obviously be affected by the configuration of the hydroxyl group in the part of the steroidal scaffold.

Stage correlation of symbiotic bacterial community and function in the development of litchi bugs (Hemiptera: Tessaratomidae).

Bacterial symbionts of insects have been shown to play important roles in host fitness. However, little is known about the bacterial community of Tessaratoma papillosa which is one of the most destructive pests of the well-known fruits Litchi chinensis Sonn and Dimocarpus longan Lour in Oriental Region, especially in South-east Asia and adjacent areas. In this study, we surveyed the bacterial community diversity and dynamics of T. papillosa in all developmental stages with both culture-dependent and culture-independent methods by the third-generation sequencing technology. Five bacterial phyla were identified in seven developmental stages of T. papillosa. Proteobacteria was the dominant phylum and Pantoea was the dominant genus of T. papillosa. The results of alpha and beta diversity analyses showed that egg stage had the most complex bacterial community. Some of different developmental stages showed similarities, which were clustered into three phases: (1) egg stage, (2) early nymph stages (instars 1-3), and (3) late nymph stages (instars 4-5) and adult stage. Functional prediction indicated that the bacterial community played different roles in these three phases. Furthermore, 109 different bacterial strains were isolated and identified from various developmental stages. This study revealed the relationship between the symbiotic bacteria and the development of T. papillosa, and may thus contribute to the biological control techniques of T. papillosa in the future.

Evaluation of Sample Preservation Approaches for Better Insect Microbiome Research According to Next-Generation and Third-Generation Sequencing.

The microbial communities associated with insects play critical roles in many physiological functions such as digestion, nutrition, and defense. Meanwhile, with the development of sequencing technology, more and more studies begin to focus on broader biodiversity of insects and the corresponding mechanisms of insect microbial symbiosis, which need longer time collecting in the field. However, few studies have evaluated the effect of insect microbiome sample preservation approaches especially in different time durations or have assessed whether these approaches are appropriate for both next-generation sequencing (NGS) and third-generation sequencing (TGS) technologies. Here, we used Tessaratoma papillosa (Hemiptera: Tessaratomidae), an important litchi pest, as the model insect and adopted two sequencing technologies to evaluate the effect of four different preservation approaches (cetyltrimethylammonium bromide (CTAB), ethanol, air dried, and RNAlater). We found the samples treated by air dried method, which entomologists adopted for morphological observation and classical taxonomy, would get worse soon. RNAlater as the most expensive approaches for insect microbiome sample preservation did not suit for field works longer than 1 month. We recommended CTAB and ethanol as better preservatives in longer time field work for their effectiveness and low cost. Comparing with the full-length 16S rRNA gene sequenced by TGS, the V4 region of 16S rRNA gene sequenced by NGS has a lower resolution trait and may misestimate the composition of microbial communities. Our results provided recommendations for suitable preservation approaches applied to insect microbiome studies based on two sequencing technologies, which can help researchers properly preserve samples in field works.

HoxA10 Facilitates SHP-1-Catalyzed Dephosphorylation of p38 MAPK/STAT3 To Repress Hepatitis B Virus Replication by a Feedback Regulatory Mechanism.

Hepatitis B virus (HBV) infection is the leading cause of chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). This study reveals a distinct mechanism underlying the regulation of HBV replication. HBV activates homeobox A10 (HoxA10) in human hepatocytes, leukocytes, peripheral blood mononuclear cells (PBMCs), HepG2-NTCP cells, leukocytes isolated from CHB patients, and HBV-associated HCC tissues. HoxA10 in turn represses HBV replication in human hepatocytes, HepG2-NTCP cells, and BALB/c mice. Interestingly, we show that during early HBV infection, p38 mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) were activated to facilitate HBV replication; however, during late HBV infection, HoxA10 was induced to attenuate HBV replication. Detailed studies reveal that HoxA10 binds to p38 MAPK, recruits SH2-containing protein tyrosine phosphatase 1 (SHP-1) to facilitate SHP-1 in catalyzing dephosphorylation of p38 MAPK/STAT3, and thereby attenuates p38 MAPK/STAT3 activation and HBV replication. Furthermore, HoxA10 binds to the HBV enhancer element I (EnhI)/X promoter, competes with STAT3 for binding of the promoter, and thereby represses HBV transcription. Taken together, these results show that HoxA10 attenuates HBV replication through repressing the p38 MAPK/STAT3 pathway by two approaches: HoxA10 interacts with p38 MAPK and recruits SHP-1 to repress HBV replication, and HoxA10 binds to the EnhI/X promoter and competes with STAT3 to attenuate HBV transcription. Thus, the function of HoxA10 is similar to the action of interferon (IFN) in terms of inhibition of HBV infection; however, the mechanism of HoxA10-mediated repression of HBV replication is different from the mechanism underlying IFN-induced inhibition of HBV infection.IMPORTANCE Two billion people have been infected with HBV worldwide; about 240 million infected patients developed chronic hepatitis B (CHB), and 650,000 die each year from liver cirrhosis (LC) or hepatocellular carcinoma (HCC). This work elucidates a mechanism underlying the control of HBV replication. HBV infection activates HoxA10, a regulator of cell differentiation and cancer progression, in human cells and patients with CHB and HCC. HoxA10 subsequently inhibits HBV replication in human tissue culture cells and mice. Additionally, HoxA10 interacts with p38 MAPK to repress the activation of p38 MAPK and STAT3 and recruits and facilitates SHP-1 to catalyze the dephosphorylation of p38 MAPK and STAT3. Moreover, HoxA10 competes with STAT3 for binding of the HBV X promoter to repress HBV transcription. Thus, this work reveals a negative regulatory mechanism underlying the control of HBV replication and provides new insights into the development of potential agents to control HBV infection.

Blastococcus deserti sp. nov., isolated from a desert sample.

A Gram-positive and aerobic actinobacterium, strain SYSU D8006T, was isolated from a desert sand sample collected from Gurbantunggut desert, China. Phenotypically, the strain was found to grow at 14-50 °C, pH 6.0-9.0 and in the presence of up to 4% (w/v) NaCl. The chemotaxonomic features of strain SYSU D8006T included menaquinone MK-9(H4) as the respiratory quinone, diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside as known polar lipids, iso-C15:0, iso-C16:0, C17:1ω8c and C18:1ω9c as the predominant fatty acids, and arabinose, galactose and glucose as the whole cell sugars. Strain SYSU D8006T shared the highest 16S rRNA gene sequence identity with Blastococcus jejuensis DSM 19597T (98.2%). Based on the analyses of the phenotypic, genotypic and phylogenetic characteristics, strain SYSU D8006T is characterized to represent a novel species of the genus Blastococcus, for which the name Blastococcus deserti sp. nov. is proposed. The type strain is SYSU D8006T (= CGMCC 1.15935T = KCTC 49026T = CPCC 204618T).

Botryobacter ruber gen. nov., sp. nov., a novel member of the family Hymenobacteraceae.

Strain SYSU D60016T, a rod-shaped bacterium that tends to form clusters, was isolated from a soil sample collected from the Gurbantunggut desert, China. Cells were Gram-stain-negative, catalase-negative and oxidase-positive. The 16S rRNA gene sequence of strain SYSU D60016T shared less than 94 % sequence identity with members of the family Hymenobacteraceae. The strain exhibited growth at 15-50 °C, pH 6-8 and in the presence of up to 3 % (w/v) NaCl. Its chemotaxonomic features included MK-7 as the respiratory menaquinone, iso-C15 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) as major cellular fatty acids and phosphatidylethanolamine as the main polar lipid. The DNA G+C content was determined to be 50.1 % (genome). Analyses of the phylogenetic data and differences in the chemotaxonomic and biochemical features from related genera in the family Hymenobacteraceae indicated that strain SYSU D60016T merits representation of a novel species of a novel genus in the family Hymenobacteraceae. The name Botryobacter ruber gen. nov., sp. nov. is, therefore, proposed to represent the phylogenetic position of strain SYSU D60016T in the family Hymenobacteraceae. The type strain of the proposed new taxon is SYSU D60016T (=KCTC 52794T=NBRC 112957T).

Aestuariivirga litoralis gen. nov., sp. nov., a proteobacterium isolated from a water sample, and proposal of Aestuariivirgaceae fam. nov.

A Gram-stain-negative, non-motile, short rod and aerobic bacterium, designated strain SYSU M10001T, was isolated from a water sample collected from the coastal region of Pearl River Estuary, Guangdong Province, PR China. Strain SYSU M10001T showed optimal growth at 28 °C, pH 7.0 and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences and concatenation of 20 protein markers revealed a distinct lineage for strain SYSU M10001T in the order Rhizobiales. Strain SYSU M10001T showed highest 16S rRNA gene sequence similarities to Hyphomicrobium nitrativorans NL23T (91.1 %) and Hyphomicrobium hollandicum IFAM KB-677T (91.1 %). The respiratory ubiquinone was Q-8. The polar lipids of the strain comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminophospholipid, two unidentified phospholipids and three unidentified lipids. The predominant cellular fatty acids identified were C19 : 0cyclo ω8c, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The G+C content was determined to be 65.5 % (genome). On the basis of differences in the phenotypic, physiological and biochemical characteristics, and results of the phylogenetic analyses, strain SYSU M10001T is proposed to represent a novel species in a novel genus for which the name Aestuariivirga litoralis gen. nov., sp. nov. The type strain of the type species Aestuariivirga litoralis is SYSU M10001T (=NBRC 112960T=KCTC 52945T). Besides, the distinct phylogenetic lineage and the distinct chemotaxonomic profile among the families in the order Rhizobiales indicated that strain SYSU M10001T should represent a new family for which the name Aestuariivirgaceae fam. nov. is proposed.

Streptomyces desertarenae sp. nov., a novel actinobacterium isolated from a desert sample.

A Streptomyces isolate, designated strain SYSU D8023T, was isolated from a desert sand sample collected from Gurbantunggut desert, China. The characterisation of the isolate was achieved using a polyphasic taxonomic approach. The isolate was found to be Gram-positive and aerobic. The strain was found to be able to grow at 14-50 °C, pH 6.0-9.0 and in the presence of up to 7% (w/v) NaCl. Strain SYSU D8023T contains LL-diaminopimelic acid as a cell wall diamino acid. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, an unidentified glycolipid and an unidentified phospholipid. MK-9(H6) and MK-9(H8) were detected as the respiratory quinones, and anteiso-C15:0, iso-C16:0 and anteiso-C17:0 as the predominant fatty acids. Pairwise comparison of the 16S rRNA gene sequences indicated that strain SYSU D8023T has a sequence identity of 97.9% to Streptomyces barkulensis RC 1831T. The DNA G + C content of strain SYSU D8023T was determined to be 70.1 mol%. Based on the analyses of the phenotypic, genotypic and phylogenetic characteristics, strain SYSU D8023T was concluded to represent a novel species of the genus Streptomyces, for which the name Streptomyces desertarenae sp. nov. is proposed. The type strain of the species is SYSU D8023T (= CGMCC 4.7455T = KCTC 49023T).

Georgenia alba sp. nov., a novel halotolerant actinobacterium isolated from a desert sand sample.

Strain SYSU D8008T was isolated from a desert sand sample collected from Saudi Arabia. The strain was observed to be Gram-stain positive, non-motile and aerobic. It can grow at 15-37 °C, pH 6.0-10.0 and can tolerant up to 7% (w/v) NaCl. Pairwise comparison of the 16S rRNA gene sequence indicated that strain SYSU D8008T shares high sequence similarities with Georgenia deserti SYSU D8004T (96.8%) and Georgenia halophila YIM 93316T (96.8%). Menaquinone MK-8(H4) was detected as the respiratory isoprenologue. The polar lipid profile of strain SYSU D8008T was found to consist of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two phosphatidylinositol mannosides, an unidentified glycolipid and an unidentified phospholipid. Strain SYSU D8008T was found to contain anteiso-C15:0 and iso-C15:0 as the predominant fatty acids. Galactose, glucose and rhamnose were detected as the whole cell sugars. Based on the phenotypic, genotypic and phylogenetic characteristics, strain SYSU D8008T can be differentiated from other closely related members of the genus Georgenia. The strain SYSU D8008T, therefore, is concluded to represent a novel species of the genus Georgenia, for which the name Georgenia alba sp. nov. is proposed. The type strain is SYSU D8008T (= CGMCC 1.15800T = KCTC 39988T).

Microbacterium album sp. nov. and Microbacterium deserti sp. nov., two halotolerant actinobacteria isolated from desert soil.

Strains SYSU D8007T and SYSU D8014T were isolated from desert soil collected from Saudi Arabia. The two isolates were Gram-stain-positive, non-motile, aerobic and non-spore-forming. These strains were able to grow at 4-45 °C and in the presence of up to 8 % (w/v) NaCl. Strain SYSU D8007T could grow at pH 6.0-10.0, and strain SYSU D8014T at pH 5.0-10.0. They shared highest 16S rRNA gene sequence similarities with Microbacterium marinilacus YM11-607T and Microbacterium paludicola US15T. Menaquinones MK-11 and MK-12 were detected as the respiratory quinones. The polar lipid profiles of strains SYSU D8007T and SYSU D8014T consisted of diphosphatidylglycerol and phosphatidylglycerol, but differed in the number of unidentified glycolipids. Strain SYSU D8007T contained anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0 as the predominant fatty acids, while strain SYSU D8014T contained anteiso-C15 : 0 and anteiso-C17 : 0 as the major fatty acids (>10 %). While glucose, rhamnose and ribose were detected in strain SYSU D8007T as the whole-cell sugars, galactose, glucose and rhamnose were present in strain SYSU D8014T. The genomic DNA G+C content of strains SYSU D8007T and SYSU D8014T was 72.2 and 73.6 mol%, respectively. Based on phenotypic, genotypic and phylogenetic characteristics, it can be concluded that strains SYSU D8007T and SYSU D8014T represent two novel species of the genus Microbacterium, for which the names Microbacterium album sp. nov. and Microbacterium deserti sp. nov. are proposed, respectively. The type strains are SYSU D8007T (=CGMCC 1.15794T=KCTC 39990T) and SYSU D8014T (=CPCC 204619T=KCTC39991T).

Saccharopolyspora deserti sp. nov., a novel halotolerant actinobacterium isolated from a desert.

Strain SYSU D8010T was isolated from a desert sand sample collected in Saudi Arabia. The taxonomic position of the isolate was investigated by the polyphasic taxonomic approach. The isolate was found to be Gram-positive and aerobic. The strain was able to grow at 14-40 °C, pH 5.0-9.0 and in the presence of up to 22 % (w/v) NaCl. Strain SYSU D8010T contained meso-diaminopimelic acid as cell-wall diamino acid, and arabinose, fucose, galactose, glucose and rhamnose as the whole-cell sugars. The primary polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannosides. Menaquinone MK-9(H4) was detected as the respiratory quinone; and anteiso-C17 : 0, iso-C16 : 0, iso-C15 : 0 and iso-C17 : 0 as the predominant fatty acids. Pairwise comparison of the 16S rRNA gene sequences indicated that strain SYSU D8010T had a sequence similarity of 97.8 % to Saccharopolyspora halophila YIM 90500T. The genomic DNA G+C content of strain SYSU D8010T was determined to be 69.9 mol%. Based on the analyses of the phenotypic, genotypic and phylogenetic characteristics, strain SYSU D8010T was determined to represent a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora deserti sp. nov. is proposed. The type strain of the species is SYSU D8010T (=KCTC 39989T=CPCC 204620T).

Georgenia deserti sp. nov., a halotolerant actinobacterium isolated from a desert sample.

Strain SYSU D8004T was isolated from a sample collected from an arid area in Saudi Arabia. The isolate was Gram-stain-positive, non-motile, aerobic and non-spore-forming. It could grow at 4-45 °C, at pH 6.0-10.0 and in the presence of up to 17 % (w/v) NaCl. Pairwise comparison of the 16S rRNA gene sequences indicated that strain SYSU D8004T shared highest sequence similarity with Georgenia halophila YIM 93316T (96.5 %). Menaquinone MK-8(H4) was detected as the respiratory quinone. The polar lipid profile of strain SYSU D8004T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two phosphatidylinositol mannosides, two unidentified phospholipids and an unidentified glycolipid. Strain SYSU D8004T contained anteiso-C15 : 0, iso-C15 : 0 and C14 : 0 as the predominant fatty acids (>10 %). Galactose, glucose and rhamnose were detected as whole-cell sugars. Based on analyses of the phenotypic, genotypic and phylogenetic characteristics, it was determined that strain SYSU D8004T could be differentiated from other closely related members of the genus Georgenia. Strain SYSU D8004T is therefore considered to represent a novel species of the genus Georgenia, for which the name Georgenia deserti sp. nov. is proposed. The type strain is SYSU D8004T (=CGMCC 1.15793T=KCTC 39987T).

Saliphagus infecundisoli gen. nov., sp. nov., an extremely halophilic archaeon isolated from a saline soil.

Two extremely halophilic archaea, strains YIM 93745T and YIM 93707, were isolated from a saline soil sample collected from Loulan, China. Cells of the two strains were coccus, non-motile and Gram-stain negative. The strains were aerobic and grew at 25-50 °C (optimum, 37 °C), in the presence of 5-35 % (w/v) NaCl (optimum, 20 %), 0.01-0.1 M Mg2+ (optimum, 0.03 M) and pH 6.0-8.5 (optimum, 7.0-7.5). Cells lysed in distilled water and with 0-5 % NaCl. Major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, sulfated mannosyl glycosyl diether and two unidentified glycolipids. Phylogenetic analysis based on the 16S rRNA sequence revealed that the two strains were most closely related to Halovivax cerinus IC35T (95.1 and 95.2 % sequence similarities, respectively). The two strains, however, shared highest rpoB' gene sequence identities with Natrinema pellirubrum JCM 10476T (87.8 and 87.7 % respectively). Phylogenetic trees based on 16S rRNA and rpoB' gene sequences demonstrated a robust clade of the two strains with members of related genera of the family Natrialbaceae. The DNA G+C contents of the two strains were 64.6 and 64.4 mol%, respectively. DNA-DNA relatedness values between them were 95±2 %. Phenotypic, chemotaxonomic characteristics and phylogenetic properties suggested that the two strains YIM 93745T and YIM 93707 represent a novel species in a new genus within the family Natrialbaceae, for which the name Saliphagus infecundisoli gen. nov., sp. nov. is proposed. The type strain is YIM 93745T (=KCTC 4228T=CGMCC 1.15824T).

Nocardia cavernae sp. nov., a novel actinobacterium isolated from a karst cave sample.

A novel actinobacterial strain, designated YIM A1135T, was isolated from a soil sample collected from a karst cave in Xingyi county, Guizhou province, south-western China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were aerobic, Gram-stain-positive and partially acid-alcohol-fast. Strain YIM A1135T shared 98.3 % 16S rRNA gene sequence similarity with Nocardia jejuensis NBRC 103114T and 97.6 % with Nocardia alba YIM 30243T. DNA-DNA hybridization values between strain YIM A1135T and related type strains of the genus Nocardia were less than 70 %. In addition, meso-diaminopimelic acid was the diagnostic diamino acid in cell-wall peptidoglycan. The whole-cell sugars were fructose, mannose, galactose and glucose. The major isoprenoid quinone was MK-8(H4,ω-cycl), while the major fatty acids (>10 %) were C16 : 0, C18 : 1ω9c, C18 : 0 10-methyl and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. Mycolic acids were present. The genomic DNA G+C content of strain YIM A1135T was 66.7 mol%. Based on the results of the molecular studies supported by its morphological, physiological, chemotaxnomic and other differential phenotypic characteristics, strain YIM A1135T is considered to represent a novel species within the genus Nocardia, for which the name Nocardia cavernae sp. nov. is proposed. The type strain is YIM A1135T (=KCTC 39595T=CCTCC AA 2017030T).