Roles of sulfate-reducing bacteria in sustaining the diversity and stability of marine bacterial community.

Microbes play central roles in ocean food webs and global biogeochemical processes. Yet, the information available regarding the highly diverse bacterial communities in these systems is not comprehensive. Here we investigated the diversity, assembly process, and species coexistence frequency of bacterial communities in seawater and sediment across ∼600 km of the eastern Chinese marginal seas using 16S rRNA gene amplicon sequencing. Our analyses showed that compared with seawater, bacterial communities in sediment possessed higher diversity and experienced tight phylogenetic distribution. Neutral model analysis showed that the relative contribution of stochastic processes to the assembly process of bacterial communities in sediment was lower than that in seawater. Functional prediction results showed that sulfate-reducing bacteria (SRB) were enriched in the core bacterial sub-communities. The bacterial diversities of both sediment and seawater were positively associated with the relative abundance of SRB. Co-occurrence analysis showed that bacteria in seawater exhibited a more complex interaction network and closer co-occurrence relationships than those in sediment. The SRB of seawater were centrally located in the network and played an essential role in sustaining the complex network. In addition, further analysis indicated that the SRB of seawater helped maintain the high stability of the bacterial network. Overall, this study provided further comprehensive information regarding the characteristics of bacterial communities in the ocean, and provides new insights into keystone taxa and their roles in sustaining microbial diversity and stability in ocean.

[A Review of the Redox Regulation of Tumor Metabolism].

Metabolic aberrance is one of the hallmarks of cancer. The metabolic patterns in cancer cells are well reprogrammed to provide building blocks and energy for their sustained growth. During tumor metabolic reprogramming, reactive oxygen species (ROS) are generated and the antioxidant systems are activated. High levels of ROS lead to oxidative damage and even cell death, whereas ROS at low levels act as second messenger to regulate many signaling pathways. Recently, with the revisiting of oxidative stress, it has been found that ROS can directly mediate the redox modifications of proteins, resulting in protein conformational and functional alterations. However, only a very small portion of metabolic enzymes, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and PKM2, etc., has been reported to undergo redox modifications. Whether other metabolic enzymes are regulated by redox modifications and thus exhibit critical functions remain largely unknown. Moreover, the specific spatio-temporal targeting of redox modifications of metabolic enzymes, as well as overcoming the existed redox and metabolic adaptation, are key points to be solved. Here, we will review the reported redox modification patterns of metabolic enzymes, the involved regulatory mechanisms and their roles in tumorigenesis and tumor progress. In addition, we will discuss the future therapeutic strategies targeting redox modifications of metabolic enzymes for tumor treatment.

Agrococcus sediminis sp. nov., an actinobacterium isolated from lake sediment.

A novel strain, designated NS18T, was isolated from sediment sampled at Taihu Lake, PR China. Cells of the isolate were spherical, aerobic, non-motile, Gram-stain-positive and non-endospore-forming. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NS18T clustered in a clade of the genus Agrococcus. Its closest phylogenetic neighbour was Agrococcus lahaulensis DSM 17612T with 98.2 % 16S rRNA gene sequence similarity. The complete genome of NS18T was 2 736 037 bp and its genomic DNA G+C content was 72.8 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain NS18T and A. lahaulensis DSM 17612T based on their whole genomes were 85.1 and 28.7 %, respectively. The major fatty acids were anteiso-C17 : 0 and anteiso-C15 : 0. The predominant menaquinones were MK11 and MK12. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol and two unidentified lipids. The components of the peptidoglycan were Ala, Gly, Asp, Thr and DAB. The whole-cell sugars contained rhamnose, ribose, xylose and glucose. According to the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain NS18T (=NBRC 113859T=MCCC 1K03759T) represents a novel species, for which the name Agrococcus sediminis sp. nov is proposed.

Brevundimonas lutea sp. nov., isolated from lake sediment.

A novel Gram-negative, aerobic, rod-shaped bacterium, designated NS26T, was isolated from a sediment sample collected from Taihu Lake in China. Colonies were orange, circular, smooth and neat-edged on Reasoner's 2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NS26T belonged to the genus Brevundimonas and had the closest relationship with Brevundimonas halotolerans DSM 24448T (96.9 %). It grew at 20-37 °C (optimum, 28 °C), pH 5.5-10.5 (pH 7.0) and without NaCl. The major isoprenoid quinone was Q-10. The dominant cellular fatty acids were C18 : 1ω7c, C16 : 0 and C18 : 1ω7c 11-methyl. The polar lipid profile comprised 1,2-diacyl-3-O-(6-phosphatidyl-α-d-glucopyranosyl) glycerol, 1,2-di-O-acyl-3-O-α-d-glycopyranuronosyl glycerol, sulfoquinovosyl diacylglycerol, 1,2-di-O-acyl-3-O-[d-glycopyranosyl-(1→4)-α-d-glucopyranuronosyl] glycerol and phosphatidylglycerol. The G+C content of genomic DNA was 68.4 mol%. The average nucleotide identity value between strain NS26T and B.halotolerans DSM 24448T was 75.6 %. Based on the polyphasic taxonomic study, strain NS26T is suggested to be a novel species, for which the name Brevundimonas lutea sp. nov. is proposed. The type strain is NS26T (=CGMCC 1.13680T=NBRC 113554T).

A novel genus of the class Actinobacteria, Longivirga aurantiaca gen. nov., sp. nov., isolated from lake sediment.

A novel actinobacterial strain, designated X5T, was isolated from the sediment of Taihu Lake in China and was subjected to a polyphasic taxonomic characterization. The strain formed orange-red colonies comprising aerobic, Gram-stain-negative, rod-shaped cells on R2A agar. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the organism was closely related to the genus Sporichthya and consistently formed a distinct clade along with the members of this genus. The closest phylogenetic neighbour was Sporichthya polymorpha NBRC 12702T with 93.7 % 16S rRNA gene sequence similarity. The major fatty acids (>10 %) were iso-C16 : 0 (18.7 %), C18 : 1ω9c (18.6 %) and C17 : 1ω8c (14.0 %). The genomic DNA G+C content was 74.4 mol%. The organism contained menaquinone MK-8(H2), MK-9(H4) and an unidentified menaquinone. Polar lipids were composed of phosphatidylglycerol, an unidentified lipid, two unidentified phospholipids and two unidentified aminolipids. The whole-cell sugars contained ribose, xylose, mannose, glucose and galactose. The cell-wall peptidoglycan contained ll-diaminopimelic acid. Based on the physiological, biochemical and chemotaxonomic data, the organism is proposed to represent a novel genus and species, for which the name Longivirga aurantiaca gen. nov., sp. nov. is proposed. The type strain is X5T (=CGMCC 4.7317T=NBRC 112237T).

Follow-up Results and Clinical Significance of Magnetic Resonance Spectroscopy Combined with Fluorescence Microscopy in Resection of High Grade Supra-tentoria Gliomas.

Objective To investigate the clinical effectiveness of magnetic resonance spectroscopy (MRS) combined with sodium fluorescein(FL) in the treatment of high grade gliomas(HGG). Methods From August 2013 to 2015 November,the clinical data of 72 supratentorial HGG(WHO grade Ⅲ-Ⅳ) patients who had received surgical treatment in our hospital were retrospectively studied,among whom 43 cases received MRS combined with intra-perative FL navigation(observation group),and 29 cases only received conventional surgery(control group). Post-operative radiotherapy and chemotherapy were applied for more than 3 months. Routine enhanced MRI were performed 24-48 hours after the operation to investigate the extent of tumor resection. Six months after the operation,the quality of life of patients was evaluated by using the Karnofsky score,and 1-year postoperative survival rate and progression-free survival(PFS) were observed. Results Postoperative MRI showed that the rate of gross total resection(GTR) in observation group was significantly higher than that in control group(72.09%vs.51.72%;χ2=23.88,P=0.001),and the GTR rate of WHO grade Ⅳ tumors was significantly higher than that of WHO grade Ⅲ tumors in observation group(92.86% vs.62.07%;χ2=6.06,P=0.042). The postoperative Karnofsky score in the observation group was significantly higher than that in control group(µ=2.34,P=0.021). The mean time of follow-up was(16.4±2.4) months(8-21 months) and there was no statistical significant difference between observation group and control group in 1-year survival rate(74.07% vs.77.50%;χ2=4.90,P=0.165) and PFS [(13.2±1.2) months vs.(12.7±2.0) months;χ2=7.26,P=0.067]. In observation group,the PFS of WHO grade Ⅳ patients was significantly higher than that in control group [(14.2±0.3) months vs.(10.0±1.1) months;χ2=11.03,P=0.031]. There was also no statistical significant difference between WHO grade Ⅳ tumors in two groups in terms of 1-year survival rate(71.43% vs.72.54%;χ2=5.33,P=0.089),and there was no statistical significant difference between WHO grade Ⅲ tumors in two groups in 1-year survival rate(75.86% vs. 72.22%;χ2=3.78,P=0.250) and in PFS [(13.7±1.4) months vs.(12.4±0.8) months;χ2=4.85,P=0.083]. Conclusions MRS combined with intraoperative FL navigation technology can improve the resection rate and improve survival quality of patients,and there is no evidence that MRS combined with intraoperative FL navigation prolong the overall survival of patients with high-grade gliomas. Different outcome may be found with longer follow-up and increased simple size.

Major Metabolite Levels of Preoperative Proton Magnetic Resonance Sectroscopy and Intraoperative Fluorescence Intensity in Glioblastoma.

Objective To compare the intraoperative major metabolite level of preoperative proton magnetic resonance spectroscopy(1H-MRS)and fluorescence intensity marked with fluorescein sodium(FLs)in glioblastoma(GBM)and thus provide an objective basis for fluorescence surgical treatment of GBM. Methods All newly diagnosed patients by plain and enhanced magnetic resonance imaging from the April 1,2014 to December 31,2015 were enrolled in this study.All of them received 1H-MRS and marked with FLs.The expression of Ki67 in tumor boundary were confirmed by postoperative pathology and determined by immunostaining assay.The relationship between 1H-MRS metabolite levels and tumor fluorescence intensity was analyzed. Results Totally 33 patients were included in the study.Preoperative 1H-MRS revealed high-grade gliomas in 25 cases.The N-acetylaspartate(NAA)decreased significantly and choline(Cho)increased significantly in high-grade gliomas.The ratios of Cho/NAA,NAA/creatine(Cr),and Cho/Cr significantly differed in different tumor regions(P=0.02,P=0.01,and P=0.00,respectively).Surgical results were marked with FLs intraoperatively.Tissue fluorescence were clearly seen.There were 29 patients undergoing total resection and 4 cases undergoing subtotal resection.No acute encephalocele occured after operation,while 2 patients suffered from epilepsy.Postoperative pathology results included:28 cases were diagnosed as GBM(22 cases consistent with 1H-MRS diagnosis).The results of GBM fluorescence imaging included:the level of fluorescence intensity in tumor parenchyma was significantly higher than that in tumor boundary and peritumoral edema(P=0.01).The result of 1H-MRS metabolite analysis included:The kurtosis of NAA and of Cho and the ratio of Cho/NAA were significantly different according the fluorescence intensity in tumor parenchyma(P=0.01,P=0.02,and P=0.01).While there was no difference in the kurtosis of NAA,the kurtosis of Cho and the ratio of Cho/NAA were significantly different according the fluorescence intensity in tumor boundary(P=0.02, P=0.00).In peritumoral edema,there was no significant different in kurtosis of NAA and of Cho and in the ratio of Cho/NAA(P=0.23,P=0.09,P=0.14).Immunohistochemistry in GBM tumor boundary showed different Ki67 expressions according to different fluorescence imaging(P=0.03). Conclusions The fluorescence intensity in GBM parenchyma is higher than that in other tumor regions,and there are different metabolic levels in different fluorescence intensity.The metabolic information marked by FLs and provided by 1H-MRS before operationis are important,and the correlation between them should be further investigated.

Bacterial community shift along with the changes in operational conditions in a membrane-aerated biofilm reactor.

Membrane-aerated biofilm reactor (MABR) is a promising wastewater treatment process. Although bacteria inhabiting the MABR biofilm are important in wastewater treatment, the community composition and its correlation with operating conditions were less clear. A laboratory-scale MABR was designed to investigate the shift of bacterial community through a complete operational process by pyrosequencing the bacterial 16S rRNA genes. From around 19,000 sequences, 175 bacterial genera were retrieved, mainly belonging to Betaproteobacteria, Gammaproteobacteria, Alphaproteobacteria, Bacteroidetes, and Actinobacteria. A large number of unclassified bacterial sequences were also detected in the biofilm, suggesting a wide variety of uncharacterized species in MABR. Redundancy analysis (RDA) revealed that influent chemical oxygen demand (COD), NH4-N, and NaHCO3 concentrations could exert distinct influences on the composition of the bacterial community. The influent COD and NaHCO3 concentrations stimulated proliferation of denitrification-related species such as Dokdonella, Azospira, Hydrogenophaga, Rhodocyclaceae, and Thauera, while inhibiting the growth of Acidovorax and Sinobacteraceae. Some denitrifying Thermomonas spp. tended to survive in NH4-N-rich environments, while Flavobacterium preferred to inhabit NH4-N-poor or COD-rich environments. Conversely, the influent NH4-N and NaHCO3, to some extent, appeared to be the growth-promoting factors for nitrifying bacteria. Furthermore, the presence of potential aerobic denitrifiers such as Comamonas, Enterobacter, and Aeromonas indicated that MABR could have the capability of simultaneous aerobic and anoxic denitrification particularly during treatment of low-ammonia nitrogen sewage.

[The clinical research of the MGMT expression levels in glioma pations].

OBJECTIVE: To investigate the correlation between the expression of tumor O (6)-methylquanine DNA methyl-tranferase(MGMT) and pathological grade,and the influence of racial factors on tumor MGMT expression levels for glioma patients. METHODS: Compare and analysis the correlation between the pathological grade and MGMT levels and the racial factors on MGMT expression levels by the immunohistochemical staining on the tumor specimens of 33 Uygur and 61 Han. RESULTS: The positive rate of 61 Han gliomas pations with MGMT is 45.90% and 33 cases of the Uygur is 30.30% , there's no clear correlation between the racial factors and the tumor MGMT levels. (P >0.05). Comparative the 94 patients with pathological level and tumor MGMT level, there is no clear correlation between pathologic level and MGMT pression in tumor tissues (P >0.05). CONCLUSION: There's no clear correlation of tumor MGMT expression and pathological levels; and there's no significant effect between racial factors and expression of glioma MGMT.