Stappia taiwanensis sp. nov., isolated from a coastal thermal spring

Characterization and Whole-Genome Analysis of a Zearalenone-Degrading Stappia sp. WLB 29

Zearalenone (ZEN) is a widely distributed mycotoxin that frequently contaminates crops and animal feed. Our previous studies showed that a new strain, Stappia sp. WLB 29 with a 97.47% of similarity to Stappia indica B106^T, isolated from the soil samples in the rhizosphere of the crops in Xinjiang, was capable of effectively degrading ZEN in minimal medium. In this study, we determined the complete genomic sequence of the Stappia sp. WLB 29 (Genbank accession number: JALBGD000000000; BioProject ID in GenBank is PRJNA814005). The total length of all sequences was 4,745,415 bp with a GC content of 67.08%. Moreover, the genome-wide analysis showed the presence of laccase- and peroxiredoxin-encoding genes in Stappia sp. WLB 29, which may be associated with ZEN degradation. The genome sequence of Stappia sp. WLB 29 reported here will serve as a reference for comparative genomic studies of ZEN degradation in the feed and food industry.

Influence of Microplastics on the Growth and the Intestinal Microbiota Composition of Brine Shrimp

Microplastics (MPs) are ubiquitous in the aquatic environment and can be frequently ingested by zooplankton, leading to various effects. Brine shrimp (Artemia parthenogenetica) has an important role in the energy flow through trophic levels in different seawater systems. In this work, the influence of polyethylene (PE) and polystyrene (PS) MPs on the growth of brine shrimp and corresponding changes of gut microbiota were investigated. Our results showed that the MPs remarkably reduced the growth rate of brine shrimp, and the two types of MPs have different impacts. The average body length of brine shrimps was reduced by 17.92 and 14.95% in the PE group and PS group, respectively. MPs are mainly found in the intestine, and their exposure evidently affects the gut microbiota. By using 16S rRNA gene high-throughput sequencing, 32 phyla of bacteria were detected in the intestine, and the microbiome consisted mainly of Proteobacteria, Firmicutes, and Actinobacteria. MPs’ exposure significantly increased the gut microbial diversity. For the PE group, the proportion of Actinobacteria and Bacteroidetes increased by 45.26 and 2.73%, respectively. For the PS group, it was 54.95 and 1.27%, respectively. According to the analysis on genus level, the proportions of Ponticoccus, Seohaeicola, Polycyclovorans, and Methylophaga decreased by 46.38, 1.24, 1.07, and 2.66%, respectively, for the PE group and 57.87, 1.43, 0.88, and 2.24%, respectively, for the PS group. In contrast, the proportions of Stappia, Microbacterium, and Dietzia increased by 1.12, 23.27, and 11.59%, respectively, for the PE group, and 1.09, 3.79, and 42.96%, respectively, for the PS group. These experimental results demonstrated that the ingestion of MPs by brine shrimp can alter the composition of the gut microbiota and lead to a slow growth rate. This study provides preliminary data support for understanding the biotoxicity of MPs to invertebrate zooplankton and is conducive to the further risk assessment of MP exposure.

Stappia albiluteola sp. nov., isolated from marine sediment

A Gram-stain negative, rod-shaped, facultatively aerobic, pale-beige-coloured bacterial strain, designated F7233^T, was isolated from coastal sediment sampled at Jingzi Bay, Weihai, PR China. Cells of strain F7233^T were 0.3-0.4 µm wide, 1.2-1.4 µm wide long, non-spore-forming and motile with one flagellum. Optimum growth occurred at 30 °C, with 1.0 % (w/v) NaCl and at pH 6.5-7.0. Positive for nitrate reduction, hydrolysis of Tweens and oxidase activity. The sole respiratory quinone of strain F7233^T was ubiquinone-10 and the predominant cellular fatty acid was summed feature 8 (C_18 : 1  ω7c/C_18 : 1  ω6c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and one unidentified aminophospholipid. The G+C content of the chromosomal DNA was 63.3 mol%. Phylogenetic analysis of the 16S rRNA gene sequence revealed that the newly isolate belonged to the genus Stappia, with 96.8 % sequence similarity to Stappia indica MCCC 1A01226^T, 96.1 % similarity to Stappia stellulata JCM 20692^T and 95.5% similarity to Stappia taiwanensis CC-SPIO-10-1^T. On the basis of phylogenetic, phenotypic and chemotaxonomic data, it is considered that strain F7233^T should represent a novel species within the genus Stappia, for which the name Stappia albiluteola sp. nov. is proposed. The type strain is F7233^T (=MCCC 1H00419^T=KCTC 72859^T).

A case of Stappia indica-induced relapsing peritonitis confirmed by 16S ribosomal RNA gene sequencing analysis in a patient undergoing continuous ambulatory peritoneal dialysis

A 69-year-old woman with 26-year history of systemic lupus erythematosus and 4-year history of peritoneal dialysis was hospitalized for treatment of bacterial peritonitis. On admission, peritoneal dialysate was collected and subjected to bacterial culture. Cell count in the cloudy peritoneal dialysate was 4194/μL, and Gram-negative bacilli were detected. Vancomycin (1 g/day) and ceftazidime (1 g/day) were administered intraperitoneally, which resulted in rapid decrease in cell count in the peritoneal dialysate. However, on the 7th hospital day, peritonitis relapsed with abdominal pain and cloudy dialysate. 16S ribosomal RNA gene sequencing analysis identified Stappia indica sp. as the causative bacteria. Although treatment with 1 g/day meropenem for an additional 3 weeks was effective, bacterial peritonitis relapsed 7 days after its discontinuation. Because biofilm formation was suspected, the peritoneal catheter was removed, and she was transferred to maintenance hemodialysis. After removal of the peritoneal catheter, bacterial peritonitis never relapsed. Stappia indica was initially discovered in the deep seawater of the Indian Ocean. The bacterium is rod-shaped, Gram-negative, and oxidase- and catalase-positive. There have been no reports on the clinical effects of genus Stappia. Given the frequent relapse in the present case, Stappia indica sp. may easily form biofilms and are likely resistant to antibiotics. Timely peritoneal catheter removal may be required in some cases of bacterial peritonitis as in the present case. Further case reports are required to further elucidate the clinical effects of Stappia indica on humans.

Hongsoonwoonella zoysiae gen. nov., sp. nov., a new member of the family Stappiaceae isolated from a tidal mudflat

A Gram stain-negative bacterial strain, designated SY4-7^T, was isolated from rhizosphere mudflat of a halophyte (Zoysia sinica) collected around Seonyu Island, Republic of Korea. Cells of the organism were strictly aerobic, non-sporulating, non-motile rods and grew at 20-42 °C, pH 6-8 and 1-6% (w/v) NaCl. The 16S rRNA gene-based phylogenetic analyses revealed that strain SY4-7^T formed an independent cluster separated from the recognized genera of the family Stappiaceae, which was also supported by phylogenomic analysis-based 92-core gene sequences. The type stains of the phylogenetically closest relatives were Stappia indica (95.6% sequence similarity), Stappia stellulata (95.1%) and Roseibium hamelinense (95.1%). The isoprenoid quinone was Q-10. The polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminophospholipids, an unidentified phosphoglycolipid, an unidentified aminolipid, two unidentified phospholipids and an unidentified lipid. The major cellular fatty acids are C_18:1ω7c and C_19:1 cyclo ω8c. The G + C content of the genomic DNA is 60.7%. Discrimination of the organism from all the recognized genera of the family Stappiaceae was apparent by the chemotaxonomic and phylogenetic features. Based on the results presented here, strain SY4-7^T (= KCTC 72226^T = NBRC 113902^T) represents a novel species of a new genus in the family Stappiaceae, for which the name Hongsoonwoonella zoysiae sp. nov. is proposed.

Hartmannibacter diazotrophicus gen. nov., sp. nov., a phosphate-solubilizing and nitrogen-fixing alphaproteobacterium isolated from the rhizosphere of a natural salt-meadow plant

A phosphate-mobilizing, Gram-negative bacterium was isolated from rhizospheric soil of Plantago winteri from a natural salt meadow as part of an investigation of rhizospheric bacteria from salt-resistant plant species and evaluation of their plant-growth-promoting abilities. Cells were rods, motile, strictly aerobic, oxidase-positive and catalase-negative. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain E19T was distinct from other taxa within the class Alphaproteobacteria . Strain E19T showed less than 93.5 % 16S rRNA gene sequence similarity with members of the genera Rhizobium (≤93.5 %), Labrenzia (≤93.1 %), Stappia (≤93.1 %), Aureimonas (≤93.1 %) and Mesorhizobium (≤93.0 %) and was most closely related to Rhizobium rhizoryzae (93.5 % 16S rRNA gene sequence similarity to the type strain). The sole respiratory quinone was Q-10, and the polar lipids comprised phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, an aminolipid and an unidentified phospholipid. Major fatty acids were C18 : 1ω7c (71.4 %), summed feature 2 (C14 : 0 3-OH and/or iso-C16 : 1; 8.3 %), C20 : 0 (7.9 %) and C16 : 0 (6.1 %). The DNA G+C content of strain E19T was 59.9±0.7 mol%. The capacity for nitrogen fixation was confirmed by the presence of the nifH gene and the acetylene reduction assay. On the basis of the results of our polyphasic taxonomic study, the new isolate represents a novel genus and species, for which the name Hartmannibacter diazotrophicus gen. nov., sp. nov. is proposed. The type strain of Hartmannibacter diazotrophicus is E19T ( = LMG 27460T = KACC 17263T).

Labrenzia suaedae sp. nov., a marine bacterium isolated from a halophyte, and emended description of the genus Labrenzia

An endophytic, Gram-staining-negative bacterium was isolated from sterilized roots of a plant, Suaeda maritima, growing on tidal flats. Cells of the strain were motile by means of a single polar flagellum and colonies were pigmented light brown. Strain YC6927(T) was able to grow at 15-37 °C (optimum at 28-30 °C) and at pH 5.0-10.0 (optimum at pH 7.0-8.0). The strain was able to grow at NaCl concentrations of 0-9.0 % (w/v), with optimum growth at 0-5.0 % NaCl. Comparison of 16S rRNA gene sequences showed that the strain was a member of the genus Labrenzia, exhibiting the highest similarity to Labrenzia marina mano18(T) (97.6 % sequence similarity). Strain YC6927(T) produced light-brown carotenoid pigments. The major respiratory quinone was Q-10 and the DNA G+C content was 58.5 mol%. The DNA-DNA relatedness between strain YC6927(T) and closely related strains was between 8.2±1.8 and 20.3±1.5 %. Strain YC6927(T) contained summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C14 : 0 3-OH as major fatty acids, confirming the affiliation of the strain with the genus Labrenzia. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, an unknown aminolipid, an unknown phospholipid and five unknown lipids. On the basis of phylogenetic analysis, physiological and biochemical characterization and DNA-DNA hybridization data, strain YC6927(T) should be assigned to a novel species of the genus Labrenzia, for which the name Labrenzia suaedae sp. nov. is proposed. The type strain is YC6927(T) ( = KACC 13772(T) = DSM 22153(T)). An emended description of the genus Labrenzia is also proposed.