Case report: Primary pericardial angiosarcoma, a rare cause of cardiac tamponade.

Primary pericardial angiosarcoma is a rare malignancy of the pericardium with variable clinical features and imaging characteristics. Herein, we report a case of histopathologically confirmed pericardial angiosarcoma in a 66-year-old man. The patient developed cardiac tamponade in a short time period. The transthoracic echocardiography showed the presence of multiple irregular echodensities, heterogeneous in echogenicity, encasing the apex of both ventricles in the pericardial space, initially misinterpreted as pericardial effusion. The patient died of cardiogenic shock despite undergoing a surgical pericardiectomy. Pericardial angiosarcoma can manifest as a mass obliterating the pericardial sac, rather than the typical pericardial effusion observed on echocardiography. Multimodality imaging studies aid in diagnosing primary pericardial angiosarcoma, but the final diagnosis relies on tissue histopathology.

[Determination of 22 mycotoxins in milk by liquid chromatography-quadrupole/orbitrap mass spectrometry].

Mycotoxins have carcinogenic, mutagenic, hepatotoxic, nephrotoxic, immunotoxic, neurotoxic, and teratogenic properties. Thus, these substances have attracted significant attention because they pose a threat to human health. As research on mycotoxins deepens, new structural analogues of mycotoxins are constantly being discovered. In this study, a method based on high performance liquid chromatography-quadrupole/orbitrap mass spectrometry was established for the simultaneous determination of 22 mycotoxins in milk. A simple, effective, and rapid pretreatment method was optimized by focusing on the solvent type, extractant volume, and extracting salt based on the characteristics of the mycotoxins and sample matrix. The analytes were extracted using 0.5% formic acid acetonitrile solution and added with sodium chloride to separate fats from water. The samples were centrifuged at 8000 r/min (4 ℃) for 5 min using a centrifuge and then concentrated using nitrogen. The dry residue was dissolved with 50% methanol aqueous solution. Twenty-two mycotoxins were separated on a ZORBAX Eclipse Plus C18 chromatographic column (100 mm×2.1 mm, 1.7 µm), and quantitative analysis was performed using the isotope internal standard method. The analytes were determined by liquid chromatography-quadrupole/orbitrap mass spectrometry in positive electrospray ionization mode. Qualitative analyses of the compounds were performed in full mass spectrometry/data-dependent tandem mass spectrometry (MS/dd-MS2) mode. Good linearities in the range of 0.5-100.0 µg/L were observed for the 22 mycotoxins, and the correlation coefficients (R2) were greater than 0.999. The limits of detection (S/N=3) and quantification (S/N=10) ranged from 0.3 to 0.5 µg/kg and from 1.0 to 1.5 µg/kg, respectively. The average recoveries of the 22 mycotoxins at three spiked levels of 1.5, 5.0, and 15 µg/kg were between 84.7% and 100.8%, with relative standard deviations (RSDs) of 1.2%-9.9%. These findings indicate that the method has high sensitivity and accuracy as well as good precision. Finally, the method was applied to the detection and analysis of mycotoxins in 25 actual commercial milk samples. The results revealed that the selected samples were not contaminated with any of the mycotoxins analyzed. Thus, the proposed method is useful as a quick preprocessing and confirmatory method for the simultaneous determination of mycotoxins in milk.

DMSOP-cleaving enzymes are diverse and widely distributed in marine microorganisms.

Dimethylsulfoxonium propionate (DMSOP) is a recently identified and abundant marine organosulfur compound with roles in oxidative stress protection, global carbon and sulfur cycling and, as shown here, potentially in osmotolerance. Microbial DMSOP cleavage yields dimethyl sulfoxide, a ubiquitous marine metabolite, and acrylate, but the enzymes responsible, and their environmental importance, were unknown. Here we report DMSOP cleavage mechanisms in diverse heterotrophic bacteria, fungi and phototrophic algae not previously known to have this activity, and highlight the unappreciated importance of this process in marine sediment environments. These diverse organisms, including Roseobacter, SAR11 bacteria and Emiliania huxleyi, utilized their dimethylsulfoniopropionate lyase 'Ddd' or 'Alma' enzymes to cleave DMSOP via similar catalytic mechanisms to those for dimethylsulfoniopropionate. Given the annual teragram predictions for DMSOP production and its prevalence in marine sediments, our results highlight that DMSOP cleavage is likely a globally significant process influencing carbon and sulfur fluxes and ecological interactions.

Longitudinal change, gender difference and hemodynamic implications of aortoseptal angle in adults without structural heart diseases.

This is an era of function evaluation for heart, but still there are some structural changes remains to be recognized. Aorto-septal angle (AoSA) is a morphologic description of the heart and adjacent major vessel. Previous studies have shown its potential hemodynamic significance, however, these are conducted in patients with structural heart diseases. The present study investigated its longitudinal change in 140 adults without structural heart disease from 20 to 90 years old and its independent clinical correlates. The findings included: 1. Advanced age, male and presence of sigmoid IVS were independent predictors of a steep AoSA. 2. Females tend to have a wider AoSA compared to age-matched males before 70 years old but they undergo more dramatic decrease with aging so that no gender difference was found beyond 70 years old. 3. Electrocardiographic QRS axis left deviation tends to be correlated with a steeper AoSA. 4. In adults without structural heart disease, no clinically significant association between AoSA and aortic velocity was found. Further prospective study from multi-centers is needed to verify these findings.

Tissue distribution study of perfluorooctanoic acid in exposed zebrafish using MALDI mass spectrometry imaging.

Perfluorooctanoic acid (PFOA) as an emerging environmental contaminant, has become ubiquitous in the environment. It is of significance to study bioconcentration and tissue distribution of aquatic organisms for predicting the persistence of PFOA and its adverse effects on the environment and human body. However, the distribution of PFOA in different tissues is a complex physiological process affected by many factors. It is difficult to be accurately described by a simple kinetic model. In present study, a new strategy was introduced to research the PFOA distribution in tissues and estimate the exposure stages. Zebrafish were continuously exposed to 25 mg/L PFOA for 30 days to simulate environmental process. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) method was used to monitor the spatio-temporal distribution of PFOA in zebrafish tissues. By analyzing the law of change obtained from the high spatial resolution MSI data, two different enrichment trends in ten tissues were summarized by performing curve fitting. Analyzing the ratio of two types of curves, a new "exposure curve" was defined to evaluate the exposure stages. With this model, three levels (mild, moderate, and deep pollution stage) of PFOA pollution in zebrafish can be simply evaluated.

Some characteristics of clinical sequelae of COVID-19 survivors from Wuhan, China: A multi-center longitudinal study.

BACKGROUND: The pandemic of COVID-19 has a persistent impact on global health, yet its sequelae need to be addressed at a wide scale around the globe. This study aims to investigate the characteristics, prevalence, and risk factors for mid-term (>6 months) clinical sequelae in a cohort of COVID-19 survivors. METHODS: Totally 715 COVID-19 survivors discharged before April 1, 2020, from three medical centers in Wuhan, China, were included. The longitudinal study was conducted by telephone interviews based on a questionnaire including the clinical sequelae of general, respiratory, and cardiovascular systems. Demographics and some characteristics of clinical sequelae of the survivors were recorded and analyzed. Multivariate logistic regression analysis was applied to explore the risk factors for the sequelae. RESULTS: The median time interval from discharge to telephone interview was 225.0 days. The COVID-19 survivors' median ages were 69 years, and 51.3% were male. Among them, 29.9% had at least one clinical sequela. There were 19.2%, 22.7%, and 5.0% of the survivors reporting fatigue, respiratory symptoms, and cardiovascular symptoms, respectively. Comorbidities, disease severity, the application of mechanical ventilation and high-flow oxygen therapy, and the history of re-admission were associated with the presence of clinical sequelae. CONCLUSIONS: Our study provides further evidence for the prevalence and characteristics of clinical sequelae of COVID-19 survivors, suggesting long-term monitoring and management is needed for their full recovery.

Structural and Mechanistic Insights Into Dimethylsulfoxide Formation Through Dimethylsulfide Oxidation.

Dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) are widespread in marine environment, and are important participants in the global sulfur cycle. Microbiol oxidation of DMS to DMSO represents a major sink of DMS in marine surface waters. The SAR11 clade and the marine Roseobacter clade (MRC) are the most abundant heterotrophic bacteria in the ocean surface seawater. It has been reported that trimethylamine monooxygenase (Tmm, EC 1.14.13.148) from both MRC and SAR11 bacteria likely oxidizes DMS to generate DMSO. However, the structural basis of DMS oxidation has not been explained. Here, we characterized a Tmm homolog from the SAR11 bacterium Pelagibacter sp. HTCC7211 (Tmm7211). Tmm7211 exhibits DMS oxidation activity in vitro. We further solved the crystal structures of Tmm7211 and Tmm7211 soaked with DMS, and proposed the catalytic mechanism of Tmm7211, which comprises a reductive half-reaction and an oxidative half-reaction. FAD and NADPH molecules are essential for the catalysis of Tmm7211. In the reductive half-reaction, FAD is reduced by NADPH. In the oxidative half-reaction, the reduced FAD reacts with O2 to form the C4a-(hydro)peroxyflavin. The binding of DMS may repel the nicotinamide ring of NADP+, and make NADP+ generate a conformational change, shutting off the substrate entrance and exposing the active C4a-(hydro)peroxyflavin to DMS to complete the oxidation of DMS. The proposed catalytic mechanism of Tmm7211 may be widely adopted by MRC and SAR11 bacteria. This study provides important insight into the conversion of DMS into DMSO in marine bacteria, leading to a better understanding of the global sulfur cycle.

Pseudolaric Acid B Attenuates High Salt Intake-Induced Hypertensive Left Ventricular Remodeling by Modulating Monocyte/Macrophage Phenotypes.

BACKGROUND Studies in ApoE knockout mice have shown that pseudolaric acid B (PB) can act as an immunomodulatory drug and attenuate atherosclerosis progression by modulating monocyte/macrophage phenotypes. Our previous study demonstrated that high salt intake could shift the phenotype of monocytes/macrophages to an inflammatory phenotype, and that this shift was related to hypertension and hypertensive left ventricular (LV) remodeling. However, no comprehensive assessment of the effects of PB on hypertensive LV remodeling has been conducted. MATERIAL AND METHODS In this study, RAW264.7 macrophages cultured with different concentrations of NaCl were used to investigate the modulating effects of PB on macrophage phenotype. Furthermore, N-nitro-L-arginine methyl ester hypertensive mice were used to investigate the modulating effects of PB on monocyte phenotype. LV remodeling was investigated by echocardiography. LV morphologic staining (for cardiomyocyte hypertrophy and collagen deposition) was performed at the time of sacrifice. RESULTS The results showed that PB significantly improved the viability of RAW264.7 cells, suppressed their phagocytic and migration abilities, and inhibited their phenotypic shift to M1 macrophages. In addition, the blood pressure of PB-treated mice was significantly decreased relative to that of control mice. Furthermore, after PB treatment, the percentage of Ly6Chi monocytes was significantly decreased while that of Ly6Clo monocytes was apparently increased. Moreover, PB preserved LV function and alleviated myocardial fibrosis and cardiomyocyte hypertrophy as measured at the end of the experimental period. The transfer of monocytes from PB-treated mice to hypertensive mice achieved the same effects. CONCLUSIONS Together, these findings indicate that PB exerts its protective effects on hypertensive LV remodeling by modulating monocyte/macrophage phenotypes and warrants further investigation.

Fast construction of core-shell structured magnetic covalent organic framework as sorbent for solid-phase extraction of zearalenone and its derivatives prior to their determination by UHPLC-MS/MS.

Magnetic covalent organic framework nanocomposite denoted as Fe3O4@TAPB-Tp with core-shell structure was fabricated via a simple template-mediated precipitation polymerization method at mild conditions. The polyimine network shell was created through the polymerization of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and 1,3,5-triformyl-phloroglucinol (Tp) in tetrahydrofuran (THF) by the Schiff-base reaction. Featuring with large specific surface area (163.19 m2 g-1), good solution dispersibility, and high stability, the obtained Fe3O4@TAPB-Tp exhibited high adsorption capacities and fast adsorption for zearalenone and its derivatives (ZEAs). The adsorption isotherms showed multilayer adsorption dominated at low concentration and monolayer adsorption at high concentration between the interface of ZEAs and Fe3O4@TAPB-Tp. With the Fe3O4@TAPB-Tp as sorbent, a magnetic solid-phase extraction-ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for simultaneous adsorption and detection of five ZEAs in complex samples. The proposed method displayed favorable linearity, low limits of detection (0.003 ~ 0.018 µg kg-1), and good repeatability (2.37~10.4%). The developed method has been applied for real sample analysis, with recoveries of 81.27~90.26%. These results showed that Fe3O4@TAPB-Tp has a good application potential for the adsorption of ZEAs in food samples. Magnetic covalent organic framework nanocomposite (Fe3O4@TAPB-Tp) were quickly fabricated at mild conditions and used as effective adsorbent for magnetic solid-phase extraction of zearalenone and its derivatives (ZEAs) from food samples prior to ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis.

Plant metabolomics integrated with transcriptomics and rhizospheric bacterial community indicates the mitigation effects of Klebsiella oxytoca P620 on p-hydroxybenzoic acid stress in cucumber.

Accumulation of p-hydroxybenzoic acid (PHBA) in soil causes autotoxicity stress in cucumber. When the stress is mitigated by PHBA-degrading bacteria, plant metabolites have not been detected. To explore mechanisms underlining the mitigation, plant metabolites have not been combined with rhizospheric microbes, antioxidant and soil enzymes. In this study, a strain P620 of Klebsiella decomposed PHBA to acetyl CoA. Cucumber was sown into soil supplemented with P620 and/or PHBA. After addition with P620, P620 colonization and the enriched bacterial genera were observed in rhizosphere. Compared to PHBA stress alone, the combination of P620 application and PHBA stress improved plant growth, decreased PHBA concentration in soil, and increased the activities of five soil enzymes and eight antioxidant enzymes in leaves. Metabolomic and transcriptomic analysis highlighted that P620 application decreased the intensities of MAG(18:3) isomer 4, MAG(18:3) isomer 2, lysoPC 18:3 (2n isomer), 2'-deoxyadenosine-5'-monophosphate, pyridoxine, and glucarate O-phosphoric acid in PHBA-stressed leaves and down-regulated the expression of genes related to these metabolites. We propose a mechanism that P620 application alters microbial communities in PHBA-contaminated soil. Thus, the application reduces PHBA concentration in soil, activates antioxidant and soil enzymes, and also influences metabolites in leaves by affecting plant transcriptome, mitigating PHBA stress in cucumber.

A novel ATP dependent dimethylsulfoniopropionate lyase in bacteria that releases dimethyl sulfide and acryloyl-CoA.

Dimethylsulfoniopropionate (DMSP) is an abundant and ubiquitous organosulfur molecule in marine environments with important roles in global sulfur and nutrient cycling. Diverse DMSP lyases in some algae, bacteria, and fungi cleave DMSP to yield gaseous dimethyl sulfide (DMS), an infochemical with important roles in atmospheric chemistry. Here, we identified a novel ATP-dependent DMSP lyase, DddX. DddX belongs to the acyl-CoA synthetase superfamily and is distinct from the eight other known DMSP lyases. DddX catalyses the conversion of DMSP to DMS via a two-step reaction: the ligation of DMSP with CoA to form the intermediate DMSP-CoA, which is then cleaved to DMS and acryloyl-CoA. The novel catalytic mechanism was elucidated by structural and biochemical analyses. DddX is found in several Alphaproteobacteria, Gammaproteobacteria, and Firmicutes, suggesting that this new DMSP lyase may play an overlooked role in DMSP/DMS cycles.

The global sulfur cycle is a collection of geological and biological processes that circulate sulfur-containing compounds through the oceans, rocks and atmosphere. Sulfur itself is essential for life and important for plant growth, hence its widespread use in fertilizers. Marine organisms such as bacteria, algae and phytoplankton produce one particular sulfur compound, called dimethylsulfoniopropionate, or DMSP, in massive amounts. DMSP made in the oceans gets readily converted into a gas called dimethyl sulfide (DMS), which is the largest natural source of sulfur entering the atmosphere. In the air, DMS is converted to sulfate and other by-products that can act as cloud condensation nuclei, which, as the name suggests, are involved in cloud formation. In this way, DMS can influence weather and climate, so it is often referred to as 'climate-active' gas. At least eight enzymes are known to cleave DMSP into DMS gas with a few by-products. These enzymes are found in algae, bacteria and fungi, and are referred to as lyases, for the way they breakdown their target compounds (DMSP, in this case). Recently, researchers have identified some bacteria that produce DMS from DMSP without using known DMSP lyases. This suggests there are other, unidentified enzymes that act on DMSP in nature, and likely contribute to global sulfur cycling. Li, Wang et al. set out to uncover new enzymes responsible for converting the DMSP that marine bacteria produce into gaseous DMS. One new enzyme called DddX was identified and found to belong to a superfamily of enzymes quite separate to other known DMSP lyases. Li, Wang et al. also showed how DddX drives the conversion of DMSP to DMS in a two-step reaction, and that the enzyme is found across several classes of bacteria. Further experiments to characterise the protein structure of DddX also revealed the molecular mechanism for its catalytic action. This study offers important insights into how marine bacteria generate the climatically important gas DMS from DMSP, leading to a better understanding of the global sulfur cycle. It gives microbial ecologists a more comprehensive perspective of these environmental processes, and provides biochemists with data on a family of enzymes not previously known to act on sulfur-containing compounds.

Oxidation of trimethylamine to trimethylamine N-oxide facilitates high hydrostatic pressure tolerance in a generalist bacterial lineage.

High hydrostatic pressure (HHP) is a characteristic environmental factor of the deep ocean. However, it remains unclear how piezotolerant bacteria adapt to HHP. Here, we identify a two-step metabolic pathway to cope with HHP stress in a piezotolerant bacterium. Myroides profundi D25T, obtained from a deep-sea sediment, can take up trimethylamine (TMA) through a previously unidentified TMA transporter, TmaT, and oxidize intracellular TMA into trimethylamine N-oxide (TMAO) by a TMA monooxygenase, MpTmm. The produced TMAO is accumulated in the cell, functioning as a piezolyte, improving both growth and survival at HHP. The function of the TmaT-MpTmm pathway was further confirmed by introducing it into Escherichia coli and Bacillus subtilis Encoded TmaT-like and MpTmm-like sequences extensively exist in marine metagenomes, and other marine Bacteroidetes bacteria containing genes encoding TmaT-like and MpTmm-like proteins also have improved HHP tolerance in the presence of TMA, implying the universality of this HHP tolerance strategy in marine Bacteroidetes.

Comparison of Alginate Utilization Pathways in Culturable Bacteria Isolated From Arctic and Antarctic Marine Environments.

Alginate, mainly derived from brown algae, is an important carbon source that can support the growth of marine microorganisms in the Arctic and Antarctic regions. However, there is a lack of systematic investigation and comparison of alginate utilization pathways in culturable bacteria from both polar regions. In this study, 88 strains were isolated from the Arctic and Antarctic regions, of which 60 strains could grow in the medium with alginate as the sole carbon source. These alginate-utilizing strains belong to 9 genera of the phyla Proteobacteria and Bacteroidetes. The genomes of 26 alginate-utilizing strains were sequenced and genomic analyses showed that they all contain the gene clusters related to alginate utilization. The alginate transport systems of Proteobacteria differ from those of Bacteroidetes and there may be unique transport systems among different genera of Proteobacteria. The biogeographic distribution pattern of alginate utilization genes was further investigated. The alginate utilization genes are found to cluster according to bacterial taxonomy rather than geographic location, indicating that the alginate utilization genes do not evolve independently in both polar regions. This study systematically illustrates the alginate utilization pathways in culturable bacteria from the Arctic and Antarctic regions, shedding light into the distribution and evolution of alginate utilization pathways in polar bacteria.

Transcriptome Profiling Combined With Activities of Antioxidant and Soil Enzymes Reveals an Ability of Pseudomonas sp. CFA to Mitigate p-Hydroxybenzoic and Ferulic Acid Stresses in Cucumber.

Continuous-cropping leads to obstacles in crop productivity by the accumulation of p-hydroxybenzoic acid (PHBA) and ferulic acid (FA). In this study, a strain CFA of Pseudomonas was shown to have a higher PHBA- and FA-degrading ability in media and soil and the mechanisms underlying this were explored. Optimal conditions for PHBA and FA degradation by CFA were 0.2 g/l of PHBA and FA, 37°C, and pH 6.56. Using transcriptome analysis, complete pathways that converted PHBA and FA to acetyl coenzyme A were proposed in CFA. When CFA was provided with PHBA and FA, we observed upregulation of genes in the pathways and detected intermediate metabolites including vanillin, vanillic acid, and protocatechuic acid. Moreover, 4-hydroxybenzoate 3-monooxygenase and vanillate O-demethylase were rate-limiting enzymes by gene overexpression. Knockouts of small non-coding RNA (sRNA) genes, including sRNA 11, sRNA 14, sRNA 20, and sRNA 60, improved the degradation of PHBA and FA. When applied to cucumber-planted soil supplemented with PHBA and FA, CFA decreased PHBA and FA in soil. Furthermore, a reduction of superoxide radical, hydrogen peroxide, and malondialdehyde in cucumber was observed by activating superoxide dismutase, catalase, glutathione peroxidase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase in seedlings, increasing the reduced glutathione and ascorbate in leaves, and inducing catalase, urease, and phosphatase in the rhizosphere. CFA has potential to mitigate PHBA and FA stresses in cucumber and alleviate continuous-cropping obstacles.

Chest CT of COVID-19 in patients with a negative first RT-PCR test: Comparison with patients with a positive first RT-PCR test.

To compare clinical and imaging features between patients with an initial negative reverse-transcription-polymerase chain-reaction (RT-PCR) test and patients with an initial positive RT-PCR test. CT follow-up analysis in the negative RT-PCR group is also described.Thirty-three patients with SARS-CoV-2 infection confirmed by RT-PCR, with 216 lesions upon CT, were included. Demographic information and chest CT imaging features were collected.The average age in the whole study group was 46.9 ±â€Š11.1 years, with 18 males and 15 females. Patients in the positive RT-PCR test group were more likely to have a fever than patients in the negative RT-PCR test group (85.7% vs 50%, P < .05). Lesions in the positive group were more likely to be located in the peripheral area than lesions in the negative group (83.6% vs 68.2%, P < .05). Regarding the appearance of 216 lesions, ground-glass opacities (GGOs) with consolidation (43.2%) was the most common appearance in the negative group, followed by pure GGOs (31.8%), while in the positive group, pure GGOs (32%) and GGOs with interlobular septal thickening (32.8%) were both most frequent, and the difference between them was evident (P < .05). For the follow-up analysis, the largest short-axis of a lesion was smaller upon follow-up (median size 13.6 mm vs 14 mm), albeit by a smaller margin. Pure GGOs decreased in frequency, from 31.3% to 21.3%, while consolidation increased in frequency, from 7.5% to 12.5%.The manifestations of COVID-19 in patients with a first negative RT-PCR test and patients with a positive first RT-PCR test are different to some extent. The consolidation component may increase after follow-up.

Putridiphycobacter roseus gen. nov., sp. nov., isolated from Antarctic rotten seaweed.

A Gram-stain-negative, pink-pigmented, rod-shaped, non-flagellated, aerobic bacterium, designated strain SM1701T, was isolated from a rotten seaweed collected off Fildes Peninsula, King George Island, West Antarctica. The strain grew at 4-30 °C, pH 6.0-8.0 and with 0.5-5 % (w/v) NaCl. It hydrolysed gelatin and Tweens (40, 60 and 80), but did not reduce nitrates to nitrites. The major cellular fatty acids of strain SM1701T were iso-C15 : 0, iso-C15 : 1G, iso-C16 : 1G, C16 : 0 and iso-C17 : 0 3-OH. Polar lipids included phosphatidylethanolamine, one unidentified aminolipid, two unidentified glycolipids and one unidentified aminoglycolipid. The major respiratory quinone was MK-7. The genomic DNA G+C content of strain SM1701T was 34.1 mol%. It showed high 16S rRNA gene sequence similarities to Crocinitomix algicola (93.8 %) and Crocinitomix catalasitica (92.5 %) and less than 91 % sequence similarities to other known members in the family Crocinitomicaceae. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1701T constituted a distinct lineage within the family Crocinitomicaceae. The phylogenetic trees based on concatenated 261 protein sequences from genome sequences showed that strain SM1701T occupied a branch separated from those of known genera in the family of Crocinitomicaceae, indicating it may belong to a new genus. On the basis of the polyphasic characterization of strain SM1701T in this study, it is considered to represent a novel species in a new genus in the family Crocinitomicaceae, for which the name Putridiphycobacter roseus gen. nov., sp. nov. is proposed. The type strain is SM1701T (=KCTC 62302T=NBRC 113201T=CGMCC 1.16510T).

Simultaneous extraction and separation of oil, proteins, and glucosinolates from Moringa oleifera seeds.

Moringa oleifera is a worldwide cultivated edible and medicinal plant. Its seeds are rich in oil, proteins, and glucosinolates. A practical method was developed to simultaneously extract and separate the three groups of substances from M. oleifera seeds. Smashed seed material was loaded into columns with petroleum ether: ethanol 8:2 (PE-ethanol) and eluted sequentially with 4.8-fold PE-ethanol to extract oil, and 10.8-fold water to extract proteins and glucosinolates. More than 95% of oil, proteins, and glucosinolates were extracted. The extracts were separated automatically into ether (oil) phase and ethanol aqueous phase. The latter was further separated into proteins and glucosinolates by 70% ethanol precipitation. The main glucosinolate was identified by LC-MS as GLC (4-α-rhamnopyranosyloxy-benzyl glucosinolate). After purification, 22.3 g refined oil, 33.0 g proteins, and 5.5 g purified GLC from 100 g M. oleifera seeds were obtained. This study provides a simple and high-efficient method to utilize M. oleifera seeds.

Structure-Function Analysis Indicates that an Active-Site Water Molecule Participates in Dimethylsulfoniopropionate Cleavage by DddK.

The osmolyte dimethylsulfoniopropionate (DMSP) is produced in petagram quantities in marine environments and has important roles in global sulfur and carbon cycling. Many marine microorganisms catabolize DMSP via DMSP lyases, generating the climate-active gas dimethyl sulfide (DMS). DMS oxidation products participate in forming cloud condensation nuclei and, thus, may influence weather and climate. SAR11 bacteria are the most abundant marine heterotrophic bacteria; many of them contain the DMSP lyase DddK, and their dddK transcripts are relatively abundant in seawater. In a recently described catalytic mechanism for DddK, Tyr64 is predicted to act as the catalytic base initiating the ß-elimination reaction of DMSP. Tyr64 was proposed to be deprotonated by coordination to the metal cofactor or its neighboring His96. To further probe this mechanism, we purified and characterized the DddK protein from Pelagibacter ubique strain HTCC1062 and determined the crystal structures of wild-type DddK and its Y64A and Y122A mutants (bearing a change of Y to A at position 64 or 122, respectively), where the Y122A mutant is complexed with DMSP. The structural and mutational analyses largely support the catalytic role of Tyr64, but not the method of its deprotonation. Our data indicate that an active water molecule in the active site of DddK plays an important role in the deprotonation of Tyr64 and that this is far more likely than coordination to the metal or His96. Sequence alignment and phylogenetic analysis suggest that the proposed catalytic mechanism of DddK has universal significance. Our results provide new mechanistic insights into DddK and enrich our understanding of DMS generation by SAR11 bacteria.IMPORTANCE The climate-active gas dimethyl sulfide (DMS) plays an important role in global sulfur cycling and atmospheric chemistry. DMS is mainly produced through the bacterial cleavage of marine dimethylsulfoniopropionate (DMSP). When released into the atmosphere from the oceans, DMS can be photochemically oxidized into DMSO or sulfate aerosols, which form cloud condensation nuclei that influence the reflectivity of clouds and, thereby, global temperature. SAR11 bacteria are the most abundant marine heterotrophic bacteria, and many of them contain DMSP lyase DddK to cleave DMSP, generating DMS. In this study, based on structural analyses and mutational assays, we revealed the catalytic mechanism of DddK, which has universal significance in SAR11 bacteria. This study provides new insights into the catalytic mechanism of DddK, leading to a better understanding of how SAR11 bacteria generate DMS.

Acinetobacter calcoaceticus CSY-P13 Mitigates Stress of Ferulic and p-Hydroxybenzoic Acids in Cucumber by Affecting Antioxidant Enzyme Activity and Soil Bacterial Community.

Ferulic acid (FA) and p-hydroxybenzoic acid (PHBA) are main phenolic compounds accumulated in rhizosphere of continuously cropped cucumber, causing stress in plants. Microbial degradation of a mixture of FA and PHBA is not well understood in soil. We isolated a strain CSY-P13 of Acinetobacter calcoaceticus, inoculated it into soil to protect cucumber from FA and PHBA stress, and explored a mechanism underlying the protection. CSY-P13 effectively degraded a mixture of FA and PHBA in culture solution under conditions of 39.37°C, pH 6.97, and 21.59 g L-1 potassium dihydrogen phosphate, giving rise to 4-vinyl guaiacol, vanillin, vanillic acid, and protocatechuic acid. During FA and PHBA degradation, activities of superoxide dismutase (SOD), catalase, ascorbate peroxidase, and dehydroascorbate reductase in CSY-P13 were induced. Inoculated into cucumber-planted soil containing 220 µg g-1 mixture of FA and PHBA, CSY-P13 degraded FA and PHBA in soil, increased plant height, and decreased malonaldehyde, superoxide radical, and hydrogen peroxide levels in leaves. CSY-P13 also enhanced SOD, guaiacol peroxidase, catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activities; increased ascorbate and glutathione contents; and elevated transcript levels of copper/zinc SOD, manganese SOD, and catalase in leaves under FA and PHBA. Moreover, CSY-P13 increased phosphatase, catalase, urease, and sucrase activities and changed bacterial richness, diversity, and community composition by high throughput sequencing in cucumber-planted soil supplemented with the mixture of FA and PHBA. So CSY-P13 degrades the mixture of FA and PHBA in soil and mitigates stress from the two phenolic compounds in cucumber by activating antioxidant enzymes, changing soil bacterial community, and inducing soil enzymes.

Erythrobacter xanthus sp. nov., isolated from surface seawater of the South China Sea.

A Gram-reaction-negative, aerobic, oxidase- and catalase-positive, yellow-pigmented, non-flagellated, rod-shaped bacterium, designed strain SM1501T, was isolated from surface seawater of the South China Sea. SM1501T grew at 7-42 °C and with 0-11 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that SM1501T represented a member of the genus Erythrobacter, sharing the highest 16S rRNA gene sequence similarity (97.4 %) with Erythrobacter luteus and 94.2-96.5 % 16S rRNA gene sequence similarities to other species of the genus Erythrobacterwith validly published names. The average nucleotide identity (ANI) value and in silico DNA-DNA hybridization value between SM1501T and E. luteus were only 74.6 and 20.0 %, respectively. The predominant cellular fatty acids of SM1501T were C17 : 1ω6c, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The major polar lipids of the strain were phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, diphosphatidylglycerol and phosphatidylcholine and the main respiratory quinone of was Q-10. Polyphasic data presented in this paper support the notion that SM1501T represents a novel species in the genus Erythrobacter, for which the name Erythrobacter xanthus sp. nov. is proposed. The type strain of Erythrobacterxanthus is SM1501T (=KCTC 42669T=CCTCC AB 2015396T).