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A Gram-stain-negative, motile, rod-shaped bacterium, designated strain LAM2020

A novel Gram-stain-positive, aerobic, non-motile and rod-shaped bacterium, designated strain NC76-1T, was isolated from soil from a field that had undergone seven years continuous maize cropping from Liuba town located in Zhangye city, Gansu province, PR China. Colonies of strain NC76-1T were white, opaque and circular with a convex shape. The isolate was found to be able to grow at 10–40 °C (optimum 30 °C), pH 6.0 to 12.0 (optimum 7.0–8.0) and with 0–5.0 % (w/v) NaCl (optimum 0%). On the basis of the results of 16S rRNA gene sequence analysis, the strain fell within the clade of the genus Leucobacter , showing the highest sequence similarities with Leucobacter iarius 40T (97.4%), Leucobacter aridicollis CIP 108388T (97.0%), Leucobacter chromiireducens subsp. solipictus TAN 31504T (96.7%) and Leucobacter denitrificans M1T8B10T (96.7%). The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between NC76-1T and its closest relatives, L. iarius 40T, L. aridicollis CIP 108388T, L. chromiireducens subsp. solipictus TAN 31504T and L. denitrificans M1T8B10T were ≤73.5 % and 20.3%, respectively. The genomic DNA G+C content of NC76-1T was 61.5 mol%. It presented MK-11 as the predominant menaquinone. The major cellular fatty acids were anteiso-C15 : 0 (49.2 %) and iso-C16 : 0 (35.7%). The major polar lipids were found to be diphosphatidyglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminoglycolipid, five glycolipid and one unidentified lipids. The cell wall amino acids were 2,4-diaminobutyric acid, alanine, glutamic acid, glycine and threonine. On the basis of the phylogenetic, phenotypic and chemotaxonomic characteristics, strain NC76-1T is concluded to represent a novel species within the genus Leucobacter , for which the name Leucobacter chinensis sp. nov. is proposed. The type strain is NC76-1T (GDMCC 1.2286T= JCM 34651T).

A Gram-stain-negative, aerobic, non-motile, rod-shaped bacterium, designated LAMRS1T, was isolated from a soil sample collected in Hebei Province, PR China. Strain LAMRS1T was able to grow optimally in the presence of 0.5 % (w/v) NaCl, at pH 7.5 and at 30 °C. On the basis of 16S rRNA gene sequence analysis, strain LAMRS1T was closely related to members of the genus Chryseobacterium , with highest levels of sequence similarity to Chryseobacterium soli DSM 19298T (97.9 %), Chryseobacterium soldanellicola DSM 17072T (97.6%) and Chryseobacterium piperi CTMT (97.5 %). The average nucleotide identity and digital DNA–DNA hybridization values between LAMRS1T and the closely related species of C. soli DSM 19298T, C. soldanellicola DSM 17072T and C. piperi CTMT were 78.1, 78.2 and 80.7 %, and 21.7, 22.0 and 23.7 %, respectively. The draft genome sequence of LAMRS1T was 4.61 Mb, with DNA G+C content of 36.2 mol%. The major isoprenoid quinone was menaquinone-6 and iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) constituted the major cellular fatty acids. The main polar lipids were phosphatidylethanolamine, four aminolipids, three glycolipids and seven unidentified lipids. On the basis of evidence presented in this study, strain LAMRS1T represents a novel species of the genus Chryseobacterium , for which the name Chryseobacterium subflavum sp. nov. is proposed. The type strain is LAMRS1T (=JCM 33868T=KCTC 72823T).

A Gram-stain-negative, aerobic, rod-shaped and motile bacterium, named LAMW06

The overuse of the herbicide nicosulfuron (NS) has become a global environmental concern. As a potential bioremediation technology, the microbial degradation of NS shows much promise; however, the detailed mechanisms of microbial taxa responding to NS exposure require further study. An isolated soil-borne bacteria Pseudomonas nicosulfuronedens LAM1902 displaying NS degradabilities was used to characterize the molecular responses to NS exposure, and LAM1902 can degrade exceed 95% of 50 mg/L nicosulfuron under the optimal conditions. Using transcriptomic sequencing, RNA-Seq results indicated that 1102 differentially expressed genes (DEGs) were up-regulated and 702 down-regulated in response to NS. Among them, “ABC transporters,” “sulfur metabolism,” and “ribosome” gene pathways were significantly enriched (p ≤ 0.05). Several gene pathways involved in the glycolysis and pentose phosphate pathways, a two-component regulation system, as well as in bacterial chemotaxis metabolisms were up-regulated under NS exposure. Surprisingly, NS exposure showed positive effects on the production of oxalic acid that is synthesized by genes encoding glycolate oxidase through the glyoxylate cycle pathway. The results suggest that P. nicosulfuronedens LAM1902 adopt acid metabolites production strategies in response to NS, with concomitant NS degradation. Meanwhile, strain LAM1902 likely grows and survives amid NS stress by increased energy production. The present studies provide a glimpse at the molecular response of microorganisms to sulfonylurea pesticide toxicity and a potential framework for future mechanistic studies.

A gram-stain positive, aerobic, motile, rod-shaped bacterium, designated strain LAM7117T, was isolated from a sulfonylurea herbicides degrading consortium enriched with birch forest soil. The optimal temperature and pH for the growth of strain LAM7117T were 35 °C and 7.5, respectively. Strain LAM7117T could grow in the presence of NaCl with concentration up to 9% (w/v). Strain LAM7117T formed a distinct phylogenetic subclade within the genus Arthrobacter in the phylogenetic trees built with 16S rRNA gene sequences and shared the highest similarity with A. crystallopoietes JCM 2522T (97.7%). The values of digital DNA–DNA relatedness and Avery Nucleotide Identity based on the genome sequences between LAM7117T and A. crystallopoietes JCM 2522T were 21.4 and 77.4%, respectively. The genomic DNA G + C content was 65.9 mol%. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. The cell wall peptidoglycan contained the amino acids as glycine, lysine, alanine and glutamic acid. The major polar lipids present in strain LAM7117T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl inositol, two unidentified glycolipids and one unidentified lipid. The predominant menaquinones of strain LAM7117T were MK-8 and MK-9. Based on the phenotypic characteristics, chemotaxonomic data and genotypic analyses, strain LAM7117T should be classified as a novel species of genus Arthrobacter, for which the name Arthrobacter sulfonylureivorans sp. nov. is proposed. The type strain is LAM7117T (= JCM 32824T = CGMCC 1.16681T).

A Gram-stain-positive, motile, rod-shaped bacterium, designated strain LAM7113T, was isolated from soil sample collected from a birch forest in Xinjiang Uygur Autonomous Region, PR China. Strain LAM7113T grew optimally at pH 8.0, 30 °C and in the presence of 1.0 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain LAM7113T was closely related to members of the genus Paenibacillus , with the highest similarity to Paenibacillus baekrokdamisoli Back-11T (96.2 %). The genomic DNA G+C content was 43.4 mol%. The values of average nucleotide identity and DNA–DNA hybridization were 66.1 and 27.0 %, respectively, by comparing the draft genome sequences of strain LAM7113T and P. baekrokdamisoli Back-11T. Anteiso-C15 : 0 and iso-C15 : 0 were identified as the major cellular fatty acids. Menaquinone-7 was detected as the predominant respiratory quinone. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, three unidentified aminophospholipids, three unidentified glycolipids, one unidentified phospholipid and two unknown polar lipids. Based on its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM7113T is proposed to represent a novel species of the genus Paenibacillus with the name Paenibacillus solisilvae sp. nov. The type strain is LAM7113T (=CGMCC 1.16619T=JCM 32513T).

Malachite green is a common environmental pollutant that poses a great threat to non-target organisms, including humans. This study reports the characterization of a bacterial strain, Pseudomonas veronii JW3-6, which was isolated from a malachite green enrichment culture. This strain degraded malachite green efficiently in a wide range of temperature and pH levels. Under optimal degradation conditions (32.4 °C, pH 7.1, and inoculum amount of 2.5 × 107 cfu/mL), P. veronii JW3-6 could degrade 93.5% of 50 mg/L malachite green within seven days. Five intermediate products from the degradation of malachite green were identified: leucomalachite green, 4-(dimethylamino) benzophenone, 4-dimethylaminophenol, benzaldehyde, and hydroquinone. We propose a possible degradation pathway based on these findings. The present study is the first to report the degradation of malachite green by P. veronii and the identification of hydroquinone as a metabolite in the degradation pathway.

A total of five strains of nicosulfuron-degrading bacteria were isolated from a continuously cultivated microbial consortium using culturomics. Among them, a novel Pseudomonas strain, LAM1902, with the highest degradation efficiency was investigated in detail. The characteristics of nicosulfuron-degradation by LAM1902 were investigated and optimized by response surface analysis. Furthermore, non-targeted metabolomic analysis of extracellular and intracellular biodegradation of nicosulfuron by LAM1902 was carried out by liquid chromatography/mass spectroscopy (LC-MS) and gas chromatography-time-of-flight/mass spectroscopy (GC-TOF/MS). It was found that nicosulfuron was degraded by LAM1902 mainly via breaking the sulfonylurea bridge, and this degradation might be attributed to oxalate accumulation. The results of GC-TOF/MS also showed that the intracellular degradation of nicosulfuron did not occur. However, nicosulfuron exerted a significant influence on the metabolism of inositol phosphate, pyrimidine, arginine/proline, glyoxylate, and dicarboxylate metabolism and streptomycin biosynthesis. The changes of myo-inositol, trehalose, and 3-aminoisobutanoic acid were proposed as a mechanism of self-protection against nicosulfuron stress.

A Gram-stain-positive, aerobic bacterium, designated CPCC 204705T, was isolated from a desert soil sample, collected from the Badain Jaran desert. Growth of strain CPCC 204705T was observed at pH 6.0–8.0 and 15–37 °C, with optimal growth at 28 °C and pH 7.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204705T belonged to the genus Cellulomonas , showing the highest similarity (98.54 %) of 16S rRNA gene sequence to Cellulomonas oligotrophica JCM 17534T. The peptidoglycan type was A4β, containing d-ornithine and d-glutamic acids as diagnostic amino acids. Rhamnose and galactose were detected in the whole-cell hydrolysate as diagnostic sugars. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C15 : 1A, C14 : 0 and C16 : 0. The major menaquinone was MK-9 (H4) and the polar lipid system contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol mannoside, one unidentified lipid, one unidentified aminolipid and two unidentified aminophospholipids. The DNA–DNA hybridization value between strain CPCC 204705T and C. oligotrophica JCM 17534T was 7.1±0.4 %, and the value of average nucleotide identity between these two strains was 79.8 %. The DNA G+C content of strain CPCC 204705T was 75.4 mol%. Based on the results of physiological experiments, chemotaxonomic data, phylogenetic analysis and DNA–DNA hybridization value, strain CPCC 204705T should be classified as a novel Cellulomonas species. The name Cellulomonas telluris sp. nov. is proposed, with strain CPCC 204705T (=DSM 105430T=KCTC 39974T) as the type strain.

A Gram-stain-positive, aerobic, motile, rod-shaped bacterium, designated strain LAM9210T, was isolated from a saline soil sample collected from Lingxian County, Shandong Province, PR China. Analysis of the 16S rRNA gene sequence of the isolate revealed highest sequence similarities to the type strain of Sporosarcina pasteurii NCIMB 8841T (97.6 % sequence similarity). The genomic G+C content was 40.4 mol%. The average nucleotide identity and in silico DNA–DNA hybridization values between strain LAM9210T and the type strain of the most closely related species S. pasteurii NCIMB 8841T were 73.6 and 20.6 %, respectively. Strain LAM9210T was found to grow at 10–40 °C (optimum, 30 °C), at pH 6.0–10.0 (optimum, pH 9.0) and with 0–6 % (w/v) NaCl (optimum, 0.5 %), respectively. The major fatty acids were anteiso-C15 : 0 and iso-C14 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and one unidentified phospholipid. Menaquinone-7 was detected as the predorminant respiratory quinone. Strain LAM9210T contained glycine, lysine, alanine and glutamic acid as the diagnostic amino acids in the cell-wall peptidoglycan. On the basis of phenotypic, phylogenetic and genotypic data, strain LAM9210T is considered to represent a novel species of the genus Sporosarcina , for which the name Sporosarcina jiandibaonis sp. nov. is proposed. The type strain is LAM9210T (=CGMCC 1.18607T=GDMCC 1.2002T=JCM 32514T).

A novel Gram-stain positive, aerobic, motile, rod-shaped bacterium, designated strain LAM7116

The widespread use of the herbicide chlorimuron-methyl is hazard to rotational crops and causes soil degradation problems. Biodegradation is considered a promising way for removing herbicide residues from the environment. Here, a new isolated strain, Cedecea sp. LAM2020, enabled complete degradation of 100 mg/L chlorimuron-methyl within five days. Transcriptome analysis revealed that ABC transporters, atrazine degradation and purine metabolism were enriched in the KEGG pathway. Integrating GO and KEGG classification with related reports, we predict that carboxylesterases are involved in the biodegradation of chlorimuron-methyl by LAM2020. Heterologous expression of the carboxylesterase gene carH showed 26.67% degradation of 50 mg/L chlorimuron-methyl within 6 h. The intracellular potential biological response and extracellular degradation process of chlorimuron-ethyl were analyzed by the nontarget metabolomic and mass spectrometry respectively, and the biodegradation characteristics and complete mineralization pathway was revealed. The cleavage of the sulfonylurea bridge and the ester bond achieved the first step in the degradation of chlorimuron-methyl. Together, these results reveal the presence of acidolysis and enzymatic degradation of chlorimuron-methyl by strain LAM2020. Hydroponic corn experiment showed that the addition of strain LAM2020 alleviated the toxic effects of chlorimuron-ethyl on the plants. Collectively, strain LAM2020 may be a promising microbial agent for plants chlorimuron-ethyl detoxification and soil biofertilizer.

A Gram-stain-negative, aerobic, motile, rod-shaped bacterium, designated strain LAM9072T, was isolated from a sample of a sulfonylurea herbicide-degrading consortium enriched with saline soil. The optimal temperature and pH for the growth of strain LAM9072T were 35 °C and 7.0, respectively. Strain LAM9072T could grow in the presence of NaCl up to 9 % (w/v). Comparative analysis of the 16S rRNA gene sequences revealed that strain LAM9072T was closely related to members of the family Vibrionaceae , with the highest similarities to Photobacterium halotolerans MACL01T (97.7 %) and Photobacterium galatheae S2753T (97.7 %). Strain LAM9072T formed a distinct phylogenetic subclade within the genus Photobacterium in the 16S rRNA gene phylogenetic trees. The results of multi-locus sequence analysis revealed a distinct lineage with P. halotolerans MACL01T as its closest relative. The genomic G+C content was 50.2 mol%. The DNA–DNA hybridization values between strain LAM9072T and P. halotolerans LMG 22194T and P. galatheae LMG 28894T were 41.6 and 22.2 %, respectively. The average nucleotide identity values were 90.9 and 78.8 %, respectively, by comparing the draft genome sequences of strain LAM9072T and P. halotolerans LMG 22194T and P. galatheae LMG 28894T. The major fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). Ubiquinone 8 was detected as the predominant respiratory quinone. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and four unidentified lipids. Based on its phenotypic characteristics and the results of genotypic analyses, we propose that strain LAM9072T represents a novel species, for which the name Photobacterium salinisoli sp. nov. is proposed. The type strain is LAM9072T (=ACCC 19961T=JCM 30852T).

This study aims to investigate the effects of long-term nicosulfuron residue on an herbicide factory ecosystem. High-throughput sequencing was used to investigate the environmental microbial community structure and interactions. The results showed that the main contributor to the differences in the microbial community structure was the sample type, followed by oxygen content, pH and nicosulfuron residue concentration. Regardless of the presence or absence of nicosulfuron, soil, sludge, and sewage were dominated by groups of Bacteroidetes, Actinobacteria, and Proteobacteria. Long-term exposure to nicosulfuron increased alpha diversity of bacteria and archaea but significantly decreased the abundance of Bacteroidetes and Acidobateria compared to soils without nicosulfuron residue. A total of 81 possible nicosulfuron-degrading bacterial genera, e.g., Rhodococcus, Chryseobacterium, Thermomonas, Stenotrophomonas, and Bacillus, were isolated from the nicosulfuron factory environmental samples through culturomics. The co-occurrence network analysis indicated that the keystone taxa were Rhodococcus, Stenotrophomonas, Nitrospira, Terrimonas, and Nitrosomonadaceae_MND1. The strong ecological relationship between microorganisms with the same network module was related to anaerobic respiration, the carbon and nitrogen cycle, and the degradation of environmental contaminants. Synthetic community (SynCom), which provides an effective top-down approach for the critical degradation strains obtained, enhanced the degradation efficiency of nicosulfuron. The results indicated that Rhodococcus sp. was the key genus in the environment of long-term nicosulfuron exposure.

Contamination by tetracycline residues has adverse influences on the environment and is considered a pressing issue. Biodegradation is regarded as a promising way to treat tetracycline residues in the environment. Here, strain Sphingobacterium mizutaii S121, which could degrade 20 mg/L tetracycline completely within 5 days, was isolated from contaminated soil. The characteristics of tetracycline degradation by strain S121 were investigated under various culture conditions. Response surface methodology was used to predict the maximum tetracycline degradation ratio, which can be obtained under the following conditions: 31.36 °C, pH of 7.15, and inoculum volume of 5.5% (v/v). Furthermore, extracellular tetracycline biodegradation products and intracellular metabolic pathways of S121 were detected by ultraperformance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) and UHPLC-quadrupole electrospray (QE)-MS, respectively. The results identified eight possible degradation products, and three putative degradation pathways were proposed. In addition, exposure to tetracycline produced significant influences on metabolic pathways such as pyrimidine, purine, taurine and hypotaurine metabolism and lysine degradation. Consequently, the intracellular metabolic pathway response of S121 in the presence of tetracycline was proposed. These findings are presented for the first time, which will facilitate a comprehensive understanding of the mechanism of tetracycline degradation. Moreover, strain S121 can be a promising bacterium for tetracycline bioremediation.

As an ornamental flower crop, the long-term continuous monocropping of cut chrysanthemum causes frequent occurrence of diseases, seriously affecting the quality of cut chrysanthemum. The rhizosphere microbial community plays an important role in maintaining the healthy growth of plants, whereas the composition and dynamics of rhizosphere microbial community under continuous monocropping of cut chrysanthemum have not been fully revealed. In this study, the Illumina MiSeq high-throughput sequencing platform was used to monitor the dynamic changes of rhizosphere microbial communities in four varieties of cut chrysanthemum during 0–3 years of monocropping, and the soil physicochemical properties were also determined. Results showed that continuous monocropping significantly increased the fungal community richness and altered the profiles of the bacterial and fungal communities, leading to variation of community beta-diversity. With the increase of continuous cropping time, biocontrol bacteria decreased, while some plant pathogenic fungi were enriched in the rhizosphere of cut chrysanthemum. FAPROTAX-based functional prediction showed that the abundance of gene related to nitrogen and sulfur metabolism and chitin lysis was reduced in the rhizosphere of cut chrysanthemum. FUNGuild-based fungal function prediction showed that plant pathogenic fungal taxa were increasing in the rhizosphere of cut chrysanthemum, mainly Acremonium, Plectosphaerellaceae, Fusarium, and Cladosporium. Continuous cropping also reduced the content of ammonium nitrogen and increased soil salinity, resulting in deterioration of soil physical and chemical properties, which, together with the transformation of rhizosphere microbial community, became part of the reasons for the continuous cropping obstacle of cut chrysanthemum.

Exposure to toxic metals from nonferrous metal(loid) smelter soils can pose serious threats to the surrounding ecosystems, crop production, and human health. Bioremediation using microorganisms is a promising strategy for treating metal(loid)-contaminated soils. Here, a native microbial consortium with sulfate-reducing function (SRB1) enriched from smelter soils can tolerate exposures to mixtures of heavy metal(loid)s (e.g., As and Pb) or various organic flotation reagents (e.g., ethylthionocarbamate). The addition of Fe

Objective This study was performed to analyze the outcomes of calcaneal fractures using a minimally invasive internal fixation method with a thin plate and bone grafting. Methods This retrospective analysis included 21 patients treated using our minimally invasive approach. The outcome measures were the change in the Bohler and Gissane angles and the calcaneus width after fixation. The clinical outcomes were evaluated by the Maryland foot scoring system and assessment of soft tissue complications. Results The follow-up time was 12 to 18 months. The Bohler angle, Gissane angle, and width of the calcaneus were significantly different between the preoperative and postoperative periods. The rate of excellent and good outcomes was 85.7% according to the Maryland foot scoring system. The incidence of soft tissue complications was 14.3%. Conclusion Treatment of calcaneal fractures using a minimally invasive internal fixation method with a plate and bone grafting provides good to excellent clinical outcomes with few soft tissue complications.

Ovarian cancer G-protein-coupled receptor 1 (OGR1), an acid-sensitive receptor, plays a key proton-sensing role through stimulation of inositol phosphate formation. Avascular necrosis of the femoral head is characterized by apoptosis of bone cells mainly resulting from deficient local blood perfusion, eventually leading to acidification with disruption of endothelial progenitor cells' (EPCs) function. However, whether EPCs express OGR1 has not been demonstrated. This study attempted to whether OGR1 mediates the effects of acid on proliferation, migration, and angiogenesis in EPCs. FITC-UEA-I and Dil-Ac-LDL double-staining methods were used to identify EPCs. Expression of OGR1 was analyzed by RT-PCR (reverse transcription PCR) and western blot after incubation in media ranging in pH, cell counting kit-8 and cell cycle analysis were used to analyze proliferation and cell cycle distribution. Scratch test, transwell migration assay, and tube formation experiments were performed to analyze migration and vascularization of EPCs after silencing OGR1 with small interfering RNA (siRNA). The result show EPCs were positive for FITC-UEA-I and Dil-Ac-LDL double-staining and expressed OGR1. The expression of OGR1 increased gradually with decreased pH and was highest in pH 6.4 medium. Incubation in pH 6.4 medium inhibited proliferation of EPCs and caused cell cycle arrest. Silencing of OGR1 using siRNA partially reversed the effect of acidic environment on EPCs. Migration and angiogenesis of EPCs were inhibited in pH 6.4 medium, and silencing of OGR1 partially reversed this effect. The results demonstrated expression of OGR1 in EPCs, and the OGR1 mediated the effects of acidic environment on proliferation, migration, and angiogenesis of EPCs.

The present study aims to evaluate the short-term clinical effects and complications of modified three-screw fixation and conventional two-screw fixation for treating anterior pelvic ring fractures. A retrospective study of 51 patients with type B fractures was performed. 25 patients (modified group) were treated with modified three-screw fixation and the other 26 patients (conventional group) with conventional two-screw fixation. Outcome measures included operation time, intraoperative blood loss, hospital stays, postoperative complications and the Majeed score at postoperatively 2 months, 3 months, 1 year and the time of implant removal. The mean operative times and mean blood loss for modified three-screw fixation versus conventional two-screw fixation bilateral were 54.8 ± 10.7 min versus 32.3 ± 9.9 min, and 153.3 mL versus 550.0 mL (p

Endocrine-disrupting chemicals (EDCs) are a large group of environmental toxicants that pose serious risks to public health. In this study, we report a new method for the complete degradation of EDCs using a dual oxidation-action composite of biogenic manganese oxides and engineered Escherichia coli cells with surface-expressed multicopper oxidase CotA. The cotA gene from a Mn2+-oxidizing bacterium was constructed as a fusion gene “inaQ-N/cotA” with an anchoring motif inaQ-N from Pseudomonas syringae and was expressed in E. coli cells to display catalytic CotA on the cell surface. Under prolonged Mn2+-enriched culturing conditions, the engineered cells were capable of forming microspherical aggregated composites that were mainly composed of ramsdellite (MnO2). The ability of the composite to degrade two EDCs, bisphenol A (BPA) and nonylphenol (NP), was investigated. GC–MS assays identified 7 and 10 degraded intermediates using the 13C isotope from 13C-labeled BPA and 13C-labeled NP, respectively. The appearance of 13CO2 from both reaction mixtures revealed mineralization pathways of BPA and NP by this composite. Bioassays using Caenorhabditis elegans as an indicator organism demonstrated that the estrogenic activity of BPA and NP was eliminated by these degradation processes. The reaction of the composite proceeded at an acidic pH and room temperature. A consecutive three-round treatment process showed comparable levels of degradation by the composite in repeated reactions and showed that the activity could be easily recovered. Moreover, the superoxide radical levels of BPA-degradation and NP-degradation were monitored during the 24 h reaction time, and possible BPA-degradation and NP-degradation pathways by the composite were proposed.

A Gram-stain-negative, aerobic, motile, short-rod-shaped bacterium with nicosulfuron-degrading ability, designated strain LAM1902T, was isolated from a microbial consortium enriched with nicosulfuron as a sole nitrogen and energy source. The optimal temperature and pH for growth of strain LAM1902T were 30 °C and pH 6.0, respectively. Strain LAM1902T could grow in the presence of NaCl with concentration up to 4.0 % (w/v). Comparative analysis of 16S rRNA gene sequences revealed that LAM1902T was closely related to the members of the family Pseudomonadaceae to the genus Pseudomonas , with the highest similarity to Pseudomonas nitroreducens DSM 14399T (99.6 %), Pseudomonas nitritireducens WZBFD3-5A2T (99.3 %) and Pseudomonas panipatensis Esp-1T (98.8 %). Multi-locus sequence analysis based on both concatenated sequences of the 16S rRNA gene and three housekeeping genes (gyrB, rpoB and rpoD) further confirmed the intrageneric phylogenetic position of strain LAM1902T. The genomic DNA G+C content of LAM1902T was 64.8 mol%. The low values of in silico DNA–DNA hybridization (less than 43.7 %) and average nucleotide identity (less than 90.9 %) also showed that the strain was distinctly different from known species of the genus Pseudomonas . The major fatty acids were C16 : 0, C17 : 0 cyclo and anteiso C15 : 0. Ubiquinone Q-9 was detected as the predorminant respiratory quinone. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and aminophospholipid. Based on phylogenetic, phenotypic and chemotaxonomic analyses and genome comparisons, we conclude that strain LAM1902T represents a novel species, for which the name Pseudomonas nicosulfuronedens sp. nov. is proposed. The type strain is LAM1902T (=JCM 33860T=KCTC 72830T).

Background Nowadays, microbial infections have caused increasing economic losses in aquaculture industry and deteriorated worldwide environments. Many of these infections are caused by opportunistic pathogens through cell-density mediated quorum sensing (QS). The disruption of QS, known as quorum quenching (QQ), is an effective and promising way to prevent and control pathogens, driving it be the potential bio-control agents. In our previous studies, AHL lactonase AiiK was identified with many characteristics, and constitutive expression vector pELX1 was constructed to express heterologous proteins in Lactobacillus casei MCJΔ1 (L. casei MCJΔ1). In this study, recombinant strain pELCW-aiiK/L. casei MCJΔ1 (LcAiiK) and wild-type Aeromonas hydrophila (A. hydrophila) were co-cultured to test the QQ ability of LcAiiK against A. hydrophila. Results A cell wall-associated expression vector pELCW for L. casei MCJΔ1 was constructed. Localization assays revealed that the expressed AiiK was anchored at the surface layer of LcAiiK via vector pELCW-aiiK. LcAiiK (OD600 = 0.5) degraded 24.13 μM of C6-HSL at 2 h, 40.99 μM of C6-HSL at 12 h, and 46.63 μM of C6-HSL at 24 h. Over 50% LcAiiK cells maintained the pELCW-aiiK plasmid after 15 generations of cultivation without erythromycin. Furthermore, LcAiiK inhibited the swimming motility, extracellular proteolytic activity, haemolytic activity and biofilm formation of A. hydrophila AH-1 and AH-4. Conclusion The AHL lactonase AiiK is firstly and constitutively expressed at the surface layer of L. casei MCJΔ1. LcAiiK displayed considerable AHL lactonase activity and great QQ abilities against A. hydrophila AH-1 and AH-4 by attenuating their QS processes instead of killing them. Therefore, the LcAiiK can be exploited as an anti-pathogenic drug or a bio-control agent to control the AHL-mediated QS of pathogenic bacteria.

Additional file 1. Text 1. 16S rDNA sequence of A. hydrophila AH-1. Text 2. 16S rDNA sequence of A. hydrophila AH-4. Table S1. Amplification composition and condition of SOE-PCR. Fig. S1. Agarose gel electrophoresis of SOE-PCR product PslyA-NHM gene. Fig. S2. AHL lactonase activity and live cells of LcAiiK after storage at 4 °C.

N-Acyl homoserine lactones (AHLs) act as the key quorum sensing (QS) signal molecules in gram-negative bacteria, which coordinates gene expression and then activates various processes, including biofilm formation and production of virulence factors in some pathogens. Quorum quenching (QQ), which is the inactivation of the signal molecules by means of enzymatic degradation or modification, inhibits the processes of QS rather than killing the pathogens and is a promising antipathogenic strategy to control the bacterial pathogens. In this study, an AHL lactonase gene (named aiiK) was cloned from Kurthia huakuii LAM0618T and the AHL lactonase AiiK was expressed by Escherichia coli. AiiK exhibits a variable substrate spectrum and efficient degradation of the AHL compounds. The enzyme assays demonstrated that AiiK behaves as an AHL lactonase that can hydrolyze the lactone bond of the AHLs. The total hydrolytic efficiency of AiiK for C10-HSL is 3.9 s−1·mM−1. AiiK can also maintain 20% activity after 12 h incubation at 37 °C and demonstrate great resistance to α-chymotrypsin, trypsin, and protease K. Furthermore, AiiK significantly inhibits the biofilm formation and attenuates extracellular proteolytic activity and pyocyanin production of Pseudomonas aeruginosa PAO1, which indicates the potential application of AiiK as a biocontrol agent or an anti-pathogenic drug.

Nicosulfuron is a common environmental pollutant, posing a great threat to aquatic systems and causing significant damage to crops. This study reported a cold-adapted strain Oceanisphaera psychrotolerans LAM-WHM-ZC, which efficiently degrades nicosulfuron over a wide range of temperatures (5 to 40 °C). The Box-Behnken design method was used to optimize the degradation conditions. O. psychrotolerans LAM-WHM-ZC can degrade 92.4% and 74.6% of initially supplemented 100 mg/L nicosulfuron under the optimum and low temperature of 18.1 and 5 °C, respectively, within 7 days. O. psychrotolerans LAM-WHM-ZC was found to be highly efficient in degrading cinosulfuron, chlorsulfuron, rimsulfuron, bensulfuron methyl, and ethametsulfuron methyl. Metabolites from nicosulfuron degradation were identified by UPLC-MS, and a possible degradation pathway was proposed. Furthermore, O. psychrotolerans LAM-WHM-ZC can also degrade nicosulfuron in soil; 78.6% and 67.4% of the initial nicosulfuron supplemented at 50 mg/kg were removed at 18.1 and 5 °C, respectively, within 15 days.

A novel aerobic bacterium, designated strain LAM9153T, was isolated from a saline soil sample collected from Lingxian County, Shandong Province, China. Cells of strain LAM9153T were observed to be Gram-stain negative, non-motile, non-spore-forming and rod-shaped. The new isolate grew optimally at 30–35 °C, pH 7.0 and 0.5% of NaCl concentration (w/v). According to the phylogenetic analysis based on the 16S rRNA gene sequence, strain LAM9153T shares high similarity with Chitinophaga terrae Gsoil 238T (96.9%) and Chitinophaga niabensis JS 13-10T (95.9%), forming a subcluster with C. terrae Gsoil 238T, Chitinophaga cymbidii R156-2T, C. niabensis JS 13-10T and Chitinophaga soli Gsoil 219T in the phylogenetic tree. The major cellular fatty acids (> 10%) were identified as iso-C15:0, iso-C17:0 3-OH and summed features 3 (C16:1 ω6c and/or C16:1 ω7c). The predominant respiratory quinone was identified as menaquinone MK-7. The polar lipids consisted of phosphatidylethanolamine, aminophospholipid, three unidentified aminolipids and five unidentified lipids. The genomic DNA G+C content was determined to be 53.2 ± 1.6 mol%. On the basis of phylogenetic, chemotaxonomic and phenotypic data, strain LAM9153T is concluded to represent a novel species of the genus Chitinophaga, for which the name Chitinophaga salinisoli sp. nov. is proposed. The type strain is LAM9153T (= ACCC 19960T = JCM 30847T).