Distribution and diversity of filamentous bacteria in wastewater treatment plants exhibiting foaming of Taihu Lake Basin, China.

Foaming caused by filamentous bacteria in activated sludge (AS) is a common phenomenon in municipal wastewater treatment plants (WWTPs) in Taihu Lake Basin of South China. In this study, total bacterial and filamentous bacterial communities were comprehensively characterized in AS and foams from eight municipal WWTPs by high-throughput sequencing technology. Results showed that alpha diversities of total bacterial communities in foams were obviously lower than those in AS samples. The bacterial community structures were significantly different between WWTPs rather than sample types (AS vs. foam). For most WWTPs, the Actinobacteria phylum was highly enriched in foams and the most abundant genera in foams were common mycolata. Sixteen filamentous bacteria were identified against the improved bulking and foaming bacteria (BFB) database. Abundance and composition of BFB in different WWTPs and different sample types were significantly different. 'Nostocoida limicola' I Trichococcus and Microthrix were generally dominant in AS samples. The dominant BFB in foams were associated with Microthrix, Skermania, Gordonia, and Mycobacterium. A new Defluviicoccus spp. in cluster III was identified in severe and continuous foams. Moreover, dominant BFB in stable and continuous foams with light level in one typical WWTP were diverse, even, and dynamic. Bacterial co-occurrence network analysis implied that the bacterial community of AS was more sensitive to disturbance than that of foam.

Contrasting distribution of antibiotic resistance genes and microbial communities in suspended activated sludge versus attached biofilms in an integrated fixed film activated sludge (IFAS) system.

Suspended activated sludge (AS) and carrier-attached biofilms simultaneously exist in an integrated fixed film activated sludge (IFAS) system. However, the differentiation of antibiotic resistance genes (ARGs) and microbial communities in different types of biofilms is rarely reported. In this study, successions of ARGs and microbial communities of AS and two types of suspended carrier-attached biofilms over seasons were investigated in the IFAS system of one municipal wastewater treatment plant. Results showed that substantial differences were found in the distribution pattern of ARGs, bacterial communities, and predicted microbial function between AS and attached biofilms. The relative abundances of all detected ARGs in AS were significantly higher than those in attached biofilms. ARGs with higher relative abundances generally existed in K3 carrier (surface area ≥ 800 m2/m3) attached biofilms than those in K1 carrier (surface area ≥ 450 m2/m3) biofilms. The relative abundances of ARGs were negatively correlated with temperature and biochemical oxygen demand (BOD5) and positively correlated with ammonium nitrogen contents for AS but not for attached biofilms. No significant relationship was found between the extracellular polymeric substance (EPS) content and ARG abundance for all samples. Temperature, BOD5, and ammonium nitrogen contents were closely connected to microbial communities. The Bray-Curtis distance of bacterial communities between two adjacent sampling seasons for AS was larger than those of two attached biofilms. Network analysis indicated that the AS network had more positive links and intense connections than the attached biofilm networks, potentially facilitating the dissemination of ARGs. The differential distribution of ARGs among the three types of samples was significantly correlated with the microbial co-occurrence network topological properties. Bray-Curtis distance and network analysis suggest that microbial community is more robust in attached biofilms than in suspended AS. This work provides a more in-depth understanding of ARGs and microbial community distributions in wastewater biofilms.

[Estimating glomerular filtration rate based on serum cystatin C].

OBJECTIVE: To develop an estimating formula for glomerular filtration Rate (GFR) based on serum cystatin C in patients with chronic kidney disease (CKD). METHODS: Clinical characteristics of 242 CKD patients were collected. The patients were randomly divided into modeling group and model validation group. The rGFR obtained from 99mTc-DTPA clearance rate was used as a reference value of GFR. s-cystatin C was detected by latex enhanced immunoturbidimetric method. Preliminary linear regression analysis followed by multiple linear regression were performed to investigate the association between s-cystatin C and rGFR. The validity of the estimation formula was tested in the model validation group in comparison with Hoek formula and Orebro formula. RESULTS: With standardised countdown conversion, s-cystatin showed linear correlation with rGFR, with a correlation coefficient of 0.773. The multiple correlation coefficient, determination coefficient, adjusted R square and std. error of the estimation model were 0.863, 0.745, 0.742, and 0.207, respectively. The residuals P-P probability plot analysis showed that the model residuals fitted into normal distribution with homogeneity of variance. Theeformula was: eGFR = 67/s-cystatin C +3. No significant difference was found between the distribution of eGFR and rGFR. Our formula had an accuracy of 30% and 50%, which were no less than those obtained from Hoek formula and Orebro formula. The new formula also had acceptable bias and high precision. The Bland-Altman analysis and ROC curve analysis showed good applicability of the new formula. CONCLUSION: The GFR prediction formula we established has a good prediction performance as comparised with other formulae, which could be used in measuring GFR in CKD patients.

[Source of variations of serum urea levels and consideration of reference interval in urban Chengdu].

OBJECTIVE: To determine the serum Urea levels in healthy adults living in urban Chengdu and to identify factors that influence the serum urea levels for the purpose of establishing reference interval. METHODS: Serum urea levels were determined in 17 787 healthy adults in urban Chengdu who underwent physical examinations. The characteristics of distribution of serum urea levels in the population and its relationships with liver function, renal function, serum glucose, and serum lipid were analyzed. RESULTS: Increased Crea, Uric, Glu, and HDL-C levels and decreased Glb level were associated with increased serum urea levels, which was independent of the impact of sex and age. The association between serum urea and Crea, Glu, and HDL-C existed in normal healthy adults. Men had higher urea levels than women. Regardless of gender, serum urea increased with age (with a cut off point at 30, 50, 60 and 70 years). CONCLUSION: Serum urea levels in healthy adults living in urban Chengdu vary in different gender and age groups. Serum urea levels are associated with serum Crea, Glu, the HDL-C levels. It is necessary to establish gender and age-specific reference intervals for serum urea.

[Bacterial conversion of sulfur-and phosphorous-compounds and microbial diversity in sediments from a near-shore marine-cultural region].

The H2S-producing bacteria and the phosphorous-cycling bacteria in sediments from near-shore marine-cultural region were investigated. Results indicate that the bacterial H2S production in aerobic condition is the dominating process to produce H2S in the sediment of cultural pond. The total counts of H2S-producing bacteria utilizing cysteine and Na2S2O3 were 1.6 x 10(6) and 4.35 x 10(3) cells g(-1) respectively. The counts of sulfate-reducing bacteria in the sediments were very little, only 2.5 x 10(1) g(-1). Further results show that the bacterial counts of decomposing lecithin and secreting phosphatase were 2.17 x 10(5) and 1.21 x 10(6) g(-1) respectively, bacterial counts of dissolving Ca3PO4 were 6.96 x 10(3) g(-1). Traditional taxonomy and partial 16S rRNA gene sequencing on the H2S-producing and phosphate-cycling bacteria indicate that most isolates could be classified as members of the following Genera: Bacillus, Halobacillus, Microbacterium, etc.

[Comparison of hepatic protein synthesis function between Banna Minipig Inbred Line and human].

OBJECTIVE: This is a research aimed at comparing the hepatic protein synthesis function of Banna Minipig Inbred Line (BMI) with that of human so as to evaluate the possibility of porcine liver replacement of human counterpart. METHODS: The venous blood samples from BMI and volunteer participants were collected. The albumin and total protein in the separated sera were tested using Beckman delta CX7 autoanalyzer, and serum protein electrophoresis was performed. RESULTS: No significant differences in albumin and in the percentage and concentration of globulins synthesized in liver (alpha1-, alpha2- and beta-globulin) between BMI and human were observed. The percentage and concentration of gamma-globulin synthesized in the lymphocytes of BMI were significantly higher than those of human. CONCLUSION: The above findings suggested the similarity between BMI liver and human liver in respect to albumin and alpha, beta-globulin synthesis.