Perceived risk of COVID-19 hurts mental health: the mediating role of fear of COVID-19 and the moderating role of resilience.

BACKGROUND: Depression and anxiety have been found prevalent during all phases of the COVID-19 pandemic. In late December 2022, almost all COVID-19 control measures were lifted in China, leading to a surge in COVID-19 infections. The public's perceived risk and fear of COVID-19 would be increased. This study aims to examine the prevalence of depression and anxiety in the Chinese general population and explores the mediating role of fear of COVID-19 between COVID-19 perceived risk and depression/anxiety and the moderating role of resilience between fear of COVID-19 and depression/anxiety. METHODS: A cross-sectional online survey was conducted in Wenzhou, China, immediately following almost all COVID-19 control measures lifted. The 9-item Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), the COVID-19 Risk Perception Scale, the Fear of COVID-19 Scale, and the Connor-Davidson Resilience Scale (CD-RISC) were used to evaluate depression, anxiety, COVID-19 perceived risk, fear of COVID-19, and resilience, respectively. Structural Equation Modeling (SEM) with Maximum Likelihood (ML) estimator and adjusted for significant background factors was performed to test the moderated mediation. Data obtained from 935 participants were analyzed. RESULTS: The prevalence of moderate to severe depression and anxiety was 23.7% and 9.5%, respectively. The present study revealed positive associations among COVID-19 perceived risk, fear of COVID-19 and depression/anxiety, and negative associations between resilience and fear of COVID-19/depression/anxiety. Fear of COVID-19 partially mediated the association between COVID-19 perceived risk and depression/anxiety. Furthermore, resilience significantly moderated the association between fear of COVID-19 and depression/anxiety. Two moderated mediation models were constructed. CONCLUSION: Depression and anxiety were prevalent among Chinese adults during the final phase of the pandemic in China. The significant mediation role of fear of COVID-19 implies that reducing fear of COVID-19 may effectively alleviate depression and anxiety symptoms. Moreover, enhancing public resilience during an epidemic crisis is crucial for promoting mental health.

The moderated-mediation role of risk perception and intolerance of uncertainty in the association between residual symptoms and psychological distress: a cross-sectional study after COVID-19 policy lifted in China.

BACKGROUND: A considerable number of individuals infected with COVID-19 experience residual symptoms after the acute phase. However, the correlation between residual symptoms and psychological distress and underlying mechanisms are scarcely studied. We aim to explore the association between residual symptoms of COVID-19 and psychological distress, specifically depression, anxiety, and fear of COVID-19, and examine the role of risk perception and intolerance of uncertainty in the association. METHODS: A cross-sectional survey was conducted by online questionnaire-based approach in mid-January 2023. Self-reported demographic characteristics, COVID-19-related information, and residual symptoms were collected. Depression, anxiety, fear, risk perception and intolerance of uncertainty were evaluated using the Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Fear of COVID-19 Scale (FCV-19S), COVID-19 Risk Perception Scale and Intolerance of Uncertainty Scale-12 (IUS-12), respectively. Linear regression analyses were conducted to explore the associations. A moderated mediation model was then constructed to examine the role of risk perception of COVID-19 and intolerance of uncertainty in the association between residual symptoms and psychological distress. RESULTS: 1735 participants effectively completed the survey. 34.9% of the patients experienced residual symptoms after acute phase of COVID-19. Psychological distress was markedly increased by COVID-19 infection, while residual symptoms had a significant impact on psychological distress (Ps < 0.001), including depression (ß = 0.23), anxiety (ß = 0.21), and fear of COVID-19 (ß = 0.14). Risk perception served as a mediator between residual symptoms and all forms of psychological distress, while intolerance of uncertainty moderated the effect of risk perception on depression and anxiety. CONCLUSION: A considerable proportion of patients experience residual symptoms after acute phase of COVID-19, which have a significant impact on psychological distress. Risk perception and intolerance of uncertainty play a moderated-mediation role in the association between residual symptoms and depression/anxiety. It highly suggests that effective treatment for residual symptoms, maintaining appropriate risk perception and improving intolerance of uncertainty are critical strategies to alleviate COVID-19 infection-associated psychological distress.

Three Weekly Intra-Articular Injections of Hylan G-F 20 vs Arthrocentesis in Patients with Chronic Idiopathic Knee Osteoarthritis: A Multicenter, Evaluator- and Patient-Blinded, Randomized Controlled Trial.

Background: Knee osteoarthritis is a leading cause of disability worldwide. Symptoms can vary over time, leading to episodes of worsened symptoms known as flares. Intra-articular injection of hyaluronic acid has demonstrated long-term symptomatic relief in the broader knee osteoarthritis population, although its use in the flare population has not been extensively examined. Objective: To assess the efficacy and safety of 3 once-weekly intra-articular injections of hylan G-F 20 (as single and repeat courses) in patients with chronic knee osteoarthritis, including a subpopulation that experienced flare. Methods: Prospective randomized controlled, evaluator- and patient-blinded, multicenter trial with 2 phases: hylan G-F 20 vs arthrocentesis only (control) and 2 courses vs single-course hylan G-F 20. Primary outcomes were visual analog scale (0-100 mm) pain scores. Secondary outcomes included safety and synovial fluid analysis. Results: Ninety-four patients (104 knees) were enrolled in Phase I, with 31 knees representing flare patients. Seventy-six patients (82 knees) were enrolled in Phase II. Long-term follow-up was 26 to 34 weeks. In flare patients, hylan G-F 20 showed significantly more improvement than the controls for all primary outcomes except pain at night (P = 0.063). Both 1 and 2 courses of hylan G-F 20 showed significant improvements from baseline for primary outcomes with no differences in efficacy between groups in the intention-to-treat population at the end of Phase II. Two courses of hylan G-F 20 showed better improvement in pain with motion (P = 0.0471) at long-term follow-up. No general side effects were reported, and local reactions (pain/swelling of the injected joint) resolved within 1 to 2 weeks. Hylan G-F 20 was also associated with reduced effusion volume and protein concentration. Conclusions: Hylan G-F 20 significantly improves pain scores vs arthrocentesis in flare patients with no safety concerns. A repeat course of hylan G-F 20 was found to be well tolerated and efficacious.

Adherence to the OARSI recommendations for designing, conducting, and reporting of clinical trials in knee osteoarthritis: a targeted literature review.

BACKGROUND: The Osteoarthritis Research Society International (OARSI) updated their guideline for clinical trials on knee osteoarthritis (KOA) in 2015, which contains recommendations for the conduct, design, and reporting of clinical trials. The purpose of this study was to assess the quality of clinical trials published between 2010 and 2020 investigating intra-articular interventions in patients with KOA using the OARSI recommendations. METHODS: A targeted literature review was conducted to identify randomized controlled trials in patients with KOA receiving intra-articular interventions, published between 2010 and 2020. Included studies were assessed using the OARSI recommendations. For a comparison between the time periods before and after the introduction of the new OARSI recommendations, the year 2016 was selected as the cut-off. RESULTS: One hundred forty-eight publications, representing 139 unique trials, were included in this review. Included studies adhered to between 9 and 24 recommendations (median: 19). The highest increase in adherence from studies published in 2016 or earlier compared to after 2016 was seen in the reporting and registration of trials and the use of structural outcome measures. Overall, adherence to the recommendations related to the collection of biochemical biomarkers and the use of structural outcome measures remained low. CONCLUSION: An improvement can be made in the conduct, design, and reporting of clinical trials for intra-articular therapies in KOA. Despite proper guidelines, quality of clinical trials varies, and the methodological deficiencies found are preventable and can be corrected. The quality of research should be considered when making treatment decisions for patients with KOA in clinical practice.

Oxygen availability affects the synthesis of quorum sensing signal in the facultative anaerobe Novosphingobium pentaromativorans US6-1.

Bacterial populations rely on quorum sensing (QS) to coordinate their behaviors and are often challenged by the fluctuation in oxygen concentrations in their habitats. Oxygen is a crucial factor that affects bacterial metabolism in multiple ways. However, little is known about whether and how oxygen availability affects QS activities. To fill this gap, we used the facultative anaerobe Novosphingobium pentaromativorans US6-1 as a model system, and observed that the QS signal acyl homoserine-lactones (AHLs) were produced only in anoxic environments, such as biofilm, or liquid medium that initially contained less than 2 mg/L dissolved oxygen, but not in highly oxic environments. Comparative transcriptome analysis revealed that oxygen availability significantly affected the physiological activities in US6-1, including fatty acid metabolism, oxidative phosphorylation, citrate cycle, QS activities, and flagellar assembly. The absence of AHLs in the oxic culture was not due to degradation, but to the very low expression of the AHL synthase gene novI. High concentration of NADH during the middle log phase under static cultivation may be a trigger for AHL synthesis. This is the first report that production of AHLs is coupled with anoxic metabolism in a facultative anaerobe, which extends our knowledge on factors affecting bacterial QS occurrence. KEY POINTS: • AHL production is anoxic cultivation related. • Oxygen availability affects AHL synthesis by influencing novI expression. • Oxygen availability changes many metabolism activities including NADH production.

Structure and product relationship analysis of acyl homoserine lactone synthases among Ensifer adhaerens reveals distinct chromosome and plasmid origins.

Despite the conservative DNA sequences among LuxI (Acyl Homoserine Lactones synthase gene) homologs, structure-product relationship of AHL synthase remains to be elucidated. In this study, through degenerate primers and in vitro expression methods, we collected the information of the gene sequences and AHL profiles from nine LuxIs among Ensifer adhaerens strains. The chromosome-encoded LuxI (C-LuxI) distinguished themselves from the plasmid-encoded ones (P-LuxI) not only in the DNA sequences, but also in AHL profiles. The C-LuxIs produced only C14-HSL, while the P-LuxIs produced predominantly C8-HSL and 3-oxo-C8-HSL. Sequence-product relationship analysis updated our recognition of the role of T140 (EsaI) in the 3-oxo-HSL production. Computational calculation based on 3D structures of these LuxIs revealed the linear relationship between the chain length and the affinity of amides to AHL synthase in C-LuxI, which was not found in the P-LuxI. We hereby proposed the linear docking affinity as a criterion for the prediction of long-chain AHL production by an AHL synthase. This study extends our understanding on the structure-product relationship of AHL synthases and revealed the distinct chromosome and plasmid origin of this enzyme among E. adhaerens.

Functional hemodynamics assessment during endovascular Tibio-pedal retrograde intervention of peripheral arterial disease.

OBJECTIVE: We sought to use a novel technique to measure the functional hemodynamics of peripheral arterial lesions during endovascular interventions. BACKGROUND: Functional hemodynamics has not been thoroughly evaluated during endovascular interventions. The aim of our study is to evaluate the feasibility and the potential benefits of pedal pressures measurements from tibio-pedal access. METHODS: We retrospectively reviewed 100 consecutive patients who underwent endovascular interventions via tibio-pedal artery access between October 3, 2018 and December 15, 2018. Baseline and postintervention pedal pressures from the pedal sheaths were measured. We also evaluated the pedal-brachial index (PBI) which is defined as the pedal sheath pressure divided by the simultaneously brachial cuff pressure. We compared baseline pedal pressures, postintervention pedal pressures, baseline PBI, postintervention PBI, % change of PBI ([postintervention PBI minus baseline PBI]/baseline PBI), and resting ankle-brachial index (ABI) versus baseline PBI in this cohort of patients. RESULTS: All 100 patients had successful tibio-pedal artery access. Baseline pedal pressure was 70 + 30 mmHg with post intervention pedal pressure of 133 + 27 mmHg (p < .001). Baseline PBI was 0.75 + 0.24 with post intervention PBI of 1.09 + 0.19 (p < .001). The correlation coefficient of resting ABI vs. baseline PBI was 0.55. The % change of PBI was 63.2 + 52.4%. There was significant improvement of postintervention PBI when compared to baseline PBI in the majority of patients. CONCLUSIONS: Obtaining pedal pressures and PBI from tibio-pedal access can be a feasible tool for endovascular interventions. This simple technique can provide us important functional hemodynamics information before and after peripheral revascularization.

Double bonds of unsaturated fatty acids differentially regulate mitochondrial cardiolipin remodeling.

BACKGROUND: Supplemented fatty acids can incorporate into cardiolipin (CL) and affect its remodeling. The change in CL species may alter the mitochondrial membrane composition, potentially disturbing the mitochondrial structure and function during inflammation. METHOD: To investigate the effect of the unsaturation of fatty acids on CL, we supplemented macrophage-like RAW264.7 cells with 18-carbon unsaturated fatty acids including oleic acid (OA, 18:1), linoleic acid (LA, 18:2), α-linolenic acid (ALA, 18:3), γ-linolenic acid (GLA, 18:3), and stearidonic acid (SDA, 18:4). Mitochondrial changes in CL were measured through mass spectrometry. RESULT: Our data indicated that OA(18:1) was the most efficient fatty acid that incorporated into CL, forming symmetrical CL without fatty acid elongation and desaturation. In addition, LA(18:2) and ALA(18:3) were further elongated before incorporation, significantly increasing the number of double bonds and the chain length of CL. GLA and SDA were not optimal substrates for remodeling enzymes. The findings of RT-qPCR experiments revealed that none of these changes in CL occurred through the regulation of CL remodeling- or synthesis-related genes. The fatty acid desaturase and transportation genes-Fads2 and Cpt1a, respectively-were differentially regulated by the supplementation of five unsaturated 18-carbon fatty acids. CONCLUSIONS: The process of fatty acid incorporation to CL was regulated by the fatty acid desaturation and transportation into mitochondria in macrophage. The double bonds of fatty acids significantly affect the incorporation process and preference. Intact OA(18:1) was incorporated to CL; LA(18:2) and ALA(18:3) were desaturated and elongated to long chain fatty acid before the incorporation; GLA(18:3) and SDA(18:4) were unfavorable for the CL incorporation.

Transcriptome Analysis of Novosphingobium pentaromativorans US6-1 Reveals the Rsh Regulon and Potential Molecular Mechanisms of N-acyl-l-homoserine Lactone Accumulation.

In most bacteria, a bifunctional Rsh responsible for (p)ppGpp metabolism is the key player in stringent response. To date, no transcriptome-wide study has been conducted to investigate the Rsh regulon, and the molecular mechanism of how Rsh affects the accumulation of N-acyl-l-homoserine lactone (AHL) remains unknown in sphingomonads. In this study, we identified an rshUS6⁻1 gene by sequence analysis in Novosphingobium pentaromativorans US6-1, a member of the sphingomonads. RNA-seq was used to determine transcription profiles of the wild type and the ppGpp-deficient rshUS6⁻1 deletion mutant (∆rsh). There were 1540 genes in the RshUS6⁻1 regulon, including those involved in common traits of sphingomonads such as exopolysaccharide biosynthesis. Furthermore, both RNA-seq and quantitative real-time polymerase chain reaction (qRT-PCR) showed essential genes for AHL production (novI and novR) were positively regulated by RshUS6⁻1 during the exponential growth phase. A degradation experiment indicated the reason for the AHL absence in ∆rsh was unrelated to the AHL degradation. According to RNA-seq, we proposed σE, DksA, Lon protease and RNA degradation enzymes might be involved in the RshUS6⁻1-dependent expression of novI and novR. Here, we report the first transcriptome-wide analysis of the Rsh regulon in sphingomonads and investigate the potential mechanisms regulating AHL accumulation, which is an important step towards understanding the regulatory system of stringent response in sphingomonads.

Evaluation of disulfide scrambling during the enzymatic digestion of bevacizumab at various pH values using mass spectrometry.

Disulfide linkages play an important role in protein stability and activity. Thus, it is critical to characterize disulfide bonds to ensure the quality and function of protein pharmaceuticals. There are, however, problems associated with maintaining disulfide linkages in the conventional procedures that are used to digest a protein. In order to preserve enzyme activity during the digestion of a protein, it is commonly carried out at neutral to basic environment which increases the possibilities of disulfide bond scrambling. However, it is not easy to differentiate whether the scrambled disulfide linkages are initiated by the sample itself or whether they are induced during the protease digestion process. In this study, the optimum pH for minimizing disulfide bond rearrangements during the digestion process was determined. Three sets of proteases, trypsin plus Glu-C, Lys-C and thermolysin were used, followed by dimethyl labeling and mass spectrometry for a bevacizumab (Avastin) disulfide linkage analysis. No disulfide linkage scrambling was detected at pH6 when Lys-C or trypsin plus Glu-C were used as enzymes. When thermolysin was applied, some scrambled disulfide bonds were identified at pH5, 6 and 7. Nevertheless, there was less disulfide bond scrambling at a lower pH. All correct disulfide bonds on bevacizumab could be identified using this approach. The results demonstrated that by choosing the proper enzymes, using a lower pH environment for the digestion could reduce the degree of artifact disulfide scrambling.

Altererythrobacter xixiisoli sp. nov., isolated from wetland soil.

A Gram-stain-negative, coccoid, yellow, non-motile, aerobic bacterium, designated strain S36T, was isolated from soil of the Xixi wetland in Zhejiang province, PR China. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain S36T could represent a novel species of genus Altererythrobacter showing highest similarity to Altererythrobacter atlanticus 26DY36T (96.31 % 16S rRNA gene sequence similarity). The temperature, pH and NaCl concentration ranges for growth were 10-37 °C (optimum 32 °C), pH 5.0-10.0 (optimum pH 7.0) and 0.5-3 % (optimum 1 %, w/v), respectively. The predominant respiratory quinone of strain S36T was Q-10. The major fatty acids were C16 : 0, C17 : 1ω6c, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The G+C content of the genomic DNA was 62.7 mol%. These data all support the affiliation of strain S36T to the genus Altererythrobacter. The polar lipids profile of strain S36T comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids and two unidentified glycolipids. The results of physiological and biochemical tests allowed differentiation of strain S36T from other members of the genus Altererythrobacter. Therefore, strain S36T represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter xixiisoli sp. nov. is proposed; the type strain is S36T (=CGMCC 1.12804T=NBRC 110413T).

Novel 16S rDNA primers revealed the diversity and habitats-related community structure of sphingomonads in 10 different niches.

It is believed that sphingomonads are ubiquitously distributed in environments. However detailed information about their community structure and their co-relationship with environmental parameters remain unclear. In this study, novel sphingomonads-specific primers based on the 16S rRNA gene were designed to investigate the distribution of sphingomonads in 10 different niches. Both in silico and in-practice tests on pure cultures and environmental samples showed that Sph384f/Sph701r was an efficient primer set. Illumina MiSeq sequencing revealed that community structures of sphingomonads were significantly different among the 10 samples, although 12 sphingomonad genera were present in all samples. Based on RDA analysis and Monte Carlo permutation test, sphingomonad community structure was significantly correlated with limnetic and marine habitat types. Among these niches, the genus Sphingomicrobium showed strong positive correlation with marine habitats, whereas genera Sphingobium, Novosphingobium, Sphingopyxis, and Sphingorhabdus showed strong positive correlation with limnetic habitats. Our study provided direct evidence that sphingomonads are ubiquitously distributed in environments, and revealed for the first time that their community structure can be correlated with habitats.

Novel acsF Gene Primers Revealed a Diverse Phototrophic Bacterial Population, Including Gemmatimonadetes, in Lake Taihu (China).

UNLABELLED: Anoxygenic phototrophs represent an environmentally important and phylogenetically diverse group of organisms. They harvest light using bacteriochlorophyll-containing reaction centers. Recently, a novel phototrophic bacterium, Gemmatimonas phototrophica, belonging to a rarely studied phylum, Gemmatimonadetes, was isolated from a freshwater lake in the Gobi Desert. To obtain more information about the environmental distribution of phototrophic Gemmatimonadetes, we collected microbial samples from the water column, upper sediment, and deeper anoxic sediment of Lake Taihu, China. MiSeq sequencing of the 16S rRNA, pufM, and bchY genes was carried out to assess the diversity of local phototrophic communities. In addition, we designed new degenerate primers of aerobic cyclase gene acsF, which serves as a convenient marker for both phototrophic Gemmatimonadetes and phototrophic Proteobacteria Our results showed that most of the phototrophic species in Lake Taihu belong to Alpha- and Betaproteobacteria Sequences of green sulfur and green nonsulfur bacteria (phototrophic Chlorobi and Chloroflexi, respectively) were found in the sediment. Using the newly designed primers, we identified a diverse community of phototrophic Gemmatimonadetes forming 30 operational taxonomic units. These species represented 10.5 and 17.3% of the acsF reads in the upper semiaerobic sediment and anoxic sediment, whereas their abundance in the water column was <1%. IMPORTANCE: Photosynthesis is one of the most fundamental biological processes on Earth. Recently, the presence of photosynthetic reaction centers has been reported from a rarely studied bacterial phylum, Gemmatimonadetes, but almost nothing is known about the diversity and environmental distribution of these organisms. The newly designed acsF primers were used to identify phototrophic Gemmatimonadetes from planktonic and sediment samples collected in Lake Taihu, China. The Gemmatimonadetes sequences were found mostly in the upper sediments, documenting the preference of Gemmatimonadetes for semiaerobic conditions. Our results also show that the phototrophic Gemmatimonadetes present in Lake Taihu were relatively diverse, encompassing 30 operational taxonomic units.

Comparison of TR Band™ and VasoStat™ Hemostasis Devices following Transpedal Catheterization for Lower Extremity Revascularization for Peripheral Arterial Disease.

BACKGROUND: Transpedal access is increasingly utilized for peripheral vascular catheterization. There is a paucity of data on the use of radial hemostasis devices as an alternative to manual compression for achievement of hemostasis after this approach. OBJECTIVE: To compare safety and efficacy of two hemostasis devices following transpedal catheterization for lower extremity revascularization for peripheral arterial disease. METHODS: A consecutive cohort of patients with bilateral Rutherford 2-5 disease who underwent transpedal catheterization for peripheral vascular interventions were retrospectively analyzed. In each patient, retrograde tibial artery access was obtained, a 4 French sheath was placed, and all revascularization was performed via tibial access. In all patients, a TR Band™ (Terumo Medical, n = 215) and/or VasoStat™ (Forge Medical, n = 99) were used to apply puncture site compression, following removal of the tibial sheath until hemostasis was achieved. Safety and efficacy of each device was compared. RESULTS: Puncture site hemostasis was achieved in all patients within 2 hours of sheath removal facilitating early discharge. Two access site pseudoaneurysms occurred within 30 days of revascularization, one of which followed TR Band™ placement and the other following VasoStat™ placement (P = 0.53). Each patient was successfully treated with ultrasound-guided thrombin injection. Loss of access site patency by duplex ultrasound occurred in 2 patients following the TR Band™ and a single patient following the VasoStat™ (P = 1.0). CONCLUSION: Both the TR Band™ and the VasoStat™ were effective in achieving hemostasis following transpedal catheterization with low rates of complications.

Flavobacterium palustre sp. nov., isolated from wetland soil.

A Gram-staining-negative, non-motile, yellow-coloured, rod-shaped bacterium, designated S44(T), was isolated from bankside soil of Xixi wetland, located in Zhejiang province, China. Growth of strain S44(T) was observed at 6-37 °C (optimum, 28 °C) and at pH 6.0-9.0 (optimum, 7.0). No growth occurred in the presence of >2 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain S44(T) represented a member of the genus Flavobacterium, showing the highest sequence similarities to the sequences from Flavobacterium succinicans DSM 4002(T) (96.9 %), Flavobacterium reichenbachii WB 3.2-61(T) (96.6 %) and Flavobacterium glycines NCBI 105008(T) (96.5 %). The G+C content of the genomic DNA was 33.6 mol%. The predominant cellular fatty acids were C15 : 0, iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (comprising C16 : 1ω7c and/or iso-C15 : 0 2-OH), and the major respiratory quinone was menaquinone 6 (MK-6). The major polar lipids were phosphatidylethanolamine, two unknown aminolipids, two unknown aminophospholipids and four unknown polar lipids. On the basis of the phenotypic and genotypic data, it is proposed that the isolate S44(T) be classified as representing a novel species of the genus Flavobacterium, for which the name Flavobacterium palustre sp. nov. is proposed. The type strain is S44(T) ( = CGMCC 1.12811(T) = NBRC 110389(T)).

Croceicoccus naphthovorans sp. nov., a polycyclic aromatic hydrocarbons-degrading and acylhomoserine-lactone-producing bacterium isolated from marine biofilm, and emended description of the genus Croceicoccus.

A polycyclic aromatic hydrocarbons-degrading and acylhomoserine-lactone-producing marine bacterium, designated strain PQ-2(T), was isolated from marine biofilm collected from a boat shell at a harbour of Zhoushan island in Zhejiang Province, PR China. Strain PQ-2(T) is Gram-stain-negative, yellow-pigmented, non-motile and short rod-shaped. Optimal growth of strain PQ-2(T) was observed at 32 °C, at pH 7.0 and in 2% (w/v) NaCl. The 16S rRNA gene sequence of strain PQ-2(T) showed highest similarity to Croceicoccus marinus E4A9(T) (96.3%) followed by Novosphingobium malaysiense MUSC 273(T) (95.6%) and Altererythrobacter marinus H32(T) (95.6%). Phylogenetic analysis with all species of the family Erythrobacteraceae with validly published names revealed that strain PQ-2(T) formed a phyletic line with Croceicoccus marinus E4A9(T) that was distinct from other members of the family Erythrobacteraceae . The sole respiratory quinone was ubiquinone 10 (Q-10). The predominant fatty acids were C18 : 1ω7c, C17 : 1ω6c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The genomic DNA G+C content was 61.7 mol%. In the polar lipid profile, phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, one unidentified phospholipid and one sphingoglycolipid were the major compounds; and another sphingoglycolipid was present in a minor amount. Based on the genotypic and phenotypic data, strain PQ-2(T) represents a novel species of the genus Croceicoccus , for which the name Croceicoccus naphthovorans sp. nov. is proposed. The type strain is PQ-2(T) ( =CGMCC 1.12805(T) =NBRC 110381(T)). In addition, emended descriptions for the genus Croceicoccus and the species C. marinus are given.

Epilithonimonas xixisoli sp. nov., isolated from wetland bank-side soil.

A novel Gram-staining-negative, non-motile and rod-shaped bacterial strain containing flexirubin-type pigments, designated S31(T), was isolated from bank-side soil of the Xixi wetland in Zhejiang province, China. Growth occurred at 10-37 °C (optimum, 32 °C), pH 6-8 (optimum, pH 7) and with 0-2 % (w/v) NaCl (optimum, 1 %). Strain S31(T) shared highest 16S rRNA gene sequence similarities with Epilithonimonas lactis H1(T) (96.2 %) and Chryseobacterium molle DW3(T) (96.4 %). Phylogenetic analysis suggested that strain S31(T) was a member of the genus Epilithonimonas. The dominant respiratory quinone was MK-6 and the DNA G+C content was 33.3 mol%. The major fatty acids were iso-C15 : 0, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) and anteiso-C15 : 0. The major polar lipids of strain S31(T) were phosphatidylethanolamine, three unidentified aminolipids and four unidentified polar lipids. Based on its phenotypic and chemotaxonomic characteristics and phylogenetic data, strain S31(T) represents a novel species of the genus Epilithonimonas, for which the name Epilithonimonas xixisoli sp. nov. (type strain S31(T) = CGMCC 1.12802(T) = NBRC 110387(T)) is proposed.

Sphingobacterium paludis sp. nov., isolated from wetland soil.

A novel Gram-stain-negative bacteria, designated S37(T), was isolated from soil of the Xixi wetland, Zhejiang province, China. Cells of strain S37(T) were aerobic, non-motile rods. Growth occurred at 10-37 °C (optimum, 25 °C), pH 5.0-9.7 (optimum, pH 7.5) and with 0-6% (w/v) NaCl (optimum, 0.5%). Based on 16S rRNA gene sequence analysis, strain S37(T) was found to be a member of the genus Sphingobacterium and shared highest similarity with Sphingobacterium composti 4M24(T) (95.78%). The major fatty acids were summed feature 3 (iso-C15:0 2-OH and/or C16:1ω7c), iso-C15:0 and iso-C17:0 3-OH, and the DNA G+C content was 43.8 mol%. The predominant respiratory quinone was MK-7. Based on its phenotypic and chemotaxonomic characteristics and phylogenetic data, strain S37(T) represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium paludis sp. nov. (type strain S37(T) = CGMCC 1.12801(T) = NBRC 110386(T)) is proposed.

Pedobacter xixiisoli sp. nov., isolated from bank soil.

A Gram-stain-negative, rod-shaped, yellow, non-motile, aerobic bacterium (strain S27(T)) was isolated from bank soil of the Xixi wetland in Zhejiang province, PR China. Phylogenetic analysis, based on its 16S rRNA gene sequence, revealed that strain S27(T) could represent a novel species of the genus Pedobacter showing highest similarity to Pedobacter koreensis WPCB189(T) (95.45%), followed by 'Pedobacter zeaxanthinifaciens' TDMA-5 (95.22%). The temperature, pH and NaCl concentration ranges for growth were 6-37 °C (optimum 28 °C), pH 5.0-9.0 (optimum pH 7.5) and 0-3% (w/v) [optimum 0.5% (w/v)], respectively. The DNA G+C content was 36.1 mol%, MK-7 was the only respiratory quinone, and iso-C(15:0), iso-C(17:0) 3-OH and summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH) were the major fatty acids. These data all support the affiliation of strain S27(T) to the genus Pedobacter. The polar lipids of strain S27(T) comprised phosphatidylethanolamine, one unidentified aminophospholipid, four unidentified aminolipids and three unidentified lipids. However, strain S27(T) could be distinguished from other members of the genus Pedobacter due to its physiological and biochemical characteristics. Therefore, strain S27(T) represents a novel species of the genus Pedobacter, for which the name Pedobacter xixiisoli sp. nov. is proposed; the type strain is S27(T) ( =CGMCC 1.12803(T) =NBRC 110388(T)).

Combination of culture-dependent and -independent methods reveals diverse acyl homoserine lactone-producers from rhizosphere of wetland plants.

The culture-dependent method and a degenerate primer-based culture-independent method were combined in an effort to identify N-acyl homoserine lactone (AHL) producers in rhizosphere of wetland plants, Salix babylonica (willow) and Phragmites australis (reed). Overall, eight potential AHL-producing genera were found, which were Aeromonas, Pseudomonas, Polymorphum, Agrobacterium, Rhizobium, Sinorhizobium, Ensifer, and Pectobacterium. Thin layer chromatograph assay revealed various AHL profiles from cultivable AHL-producers. The degenerate primer pair RAHL352F and RAHL461R was found to cover AHL synthetase genes from families Rhizobiaceae and Rhodobacteraceae. Little overlap was found in taxa of potential AHL-producers obtained by the two methods, indicating that they were well complement to each other. This is the first survey for AHL-producers that employed combined culture-dependent and -independent methods.