Lower Melatonin Indicates Poor Short-term Prognosis in Patients with Acute Ischemic Stroke.

AIMS: We evaluated endogenous melatonin levels in the acute phase of cerebral infarction and explored the impact of possible changes in melatonin levels on the prognosis of patients. METHODS: This study recruited acute ischemic stroke (AIS) patients from the Department of the Second Affiliated Hospital of Soochow University between December 2019 and June 2021, along with healthy control subjects. Salivary melatonin samples were collected from each participant between 7 pm and 10 pm, and fasting plasma was collected the following morning to measure the levels of inflammatory markers. The prognosis was assessed through follow-up three months after discharge. The relationship between melatonin levels and plasma inflammatory markers was assessed, followed by an analysis of the effect of melatonin levels on patient prognosis. RESULTS: The study enrolled a total of 160 participants, including 120 AIS patients aged 50 years or older (61.7% male) and 40 age-matched controls (55.0% male). The AIS group exhibited lower salivary melatonin levels at 19 (P = 0.002), 20 (P < 0.001), 21 (P < 0.001), and 22 (P < 0.001) o'clock, and the average melatonin level was also lower (P < 0.001). Logistic regression analysis models indicated an association between low melatonin levels and poor prognosis. Salivary melatonin levels demonstrated good predictive ability for the prognosis of AIS patients. CONCLUSION: Melatonin levels were lower in AIS patients compared to controls. In addition, lower melatonin levels were associated with a poorer prognosis among AIS patients.

Circadian Rhythm Disturbance in Acute Ischemic Stroke Patients and Its Effect on Prognosis.

INTRODUCTION: Poststroke sleep disturbances are common and can affect stroke outcomes, but the clinical studies mainly focus on breathing-related sleep disorders, while the bidirectional impact of circadian rhythm dysfunction in ischemic stroke remains unknown. This study observed the characteristics of melatonin secretion in acute ischemic stroke patients and evaluated whether melatonin rhythm impacts the prognosis after stroke by assessing the neurological function, cognition, emotion, and quality of life 3 months after stroke. METHODS: Acute ischemic stroke patients were selected from the Department of Neurology Inpatients of the Second Hospital affiliated with Soochow University from October 2019 to July 2021. Healthy control subjects were recruited at the same time. Demographic and clinical data were collected, and relevant scale scores (including neurological function, cognition, emotion, and sleep) were assessed within 2 weeks of onset and followed up 3 months later. All participants collected salivary melatonin samples on the 4th day of hospitalization and dim light melatonin onset (DLMO) was calculated according to melatonin concentration. Stroke patients were then divided into three groups based on their DLMO values. RESULTS: A total of 74 stroke patients and 33 control subjects were included in this analysis. Compared with healthy controls, stroke patients exhibited a delayed melatonin rhythm during the acute phase of stroke (21:36 vs. 20:38, p = 0.004). Stroke patients were then divided into three groups, namely normal (n = 36), delayed (n = 28), or advanced DLMO (n = 10), based on their DLMO values. A χ2 test showed that there were significant differences in the rate of poor prognosis (p = 0.011) and depression tendency (p = 0.028) among the three groups. A further pairwise comparison revealed that stroke patients with delayed DLMO were more likely to experience poor short-term outcomes than normal DLMO group (p = 0.003). The average melatonin concentration of stroke patients at 5 time points was significantly lower than that of the control group (3.145 vs. 7.065 pg/mL, p < 0.001). Accordingly, we split stroke patients into three groups, namely low melatonin level (n = 14), normal melatonin level (n = 54), or high melatonin level (n = 6). Unfortunately, there were no great differences in the clinical characteristics, cognition, emotion, sleep quality, and short-term outcome among groups. CONCLUSIONS: This is a preliminary study, and our results indicate that changes in melatonin secretion phase of stroke patients may have effect on their short-term prognosis.

A Pilot Assessment on the Role of Procalcitonin Dynamic Monitoring in the Early Diagnosis of Infection Post Cardiac Surgery.

Purpose: To evaluate the value of dynamic monitoring of procalcitonin (PCT) as a biomarker for the early diagnosis of postoperative infections in patients undergoing cardiac surgery. Methods: In total, 252 patients who underwent cardiac surgery were retrospectively included. The postoperative patients' PCT level, change value (△PCT), and clearance rate (△PCTc) were compared between the infected and noninfected groups in adult and pediatric patients on postoperative days (PODs) 1, 3, and 5. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the diagnostic value. Results: Procalcitonin concentration decreased progressively in the noninfected group in adult and pediatric patients; PCT concentration continued to rise until it peaked on POD 3 in the infected group. In adult patients, the AUC of PCT for diagnosis of infection on PODs 1, 3, and 5 were 0.626, 0.817, and 0.806, with the optimal cut-off values of 7.35, 3.63, and 1.73 ng/ml, respectively. The diagnostic efficiency of △PCT3 and △PCT C3 was significantly better than △PCT5 and △PCT C5 , respectively. In pediatric patients, the AUC of PCT for diagnosis of infection on PODs 1, 3, and 5 were 0.677, 0.747, and 0.756, respectively, and the optimal cut-off values were 27.62, 26.15, and 10.20 ng/ml. Conclusion: This study showed that dynamic monitoring of PCT levels could be an effective clinical means to help to discover postoperative infection earlier. The PCT level and its change indicators on POD 3 in adult patients and the PCT level on POD 5 in children can indicate infection.

[Water Quality and Bacterial Population Driving Mechanism of Algae Vertical Succession in Stratified Reservoir].

Phytoplankton and bacteria are important components of the aquatic food web, and play a critical role in substance circulation and energy exchange in freshwater ecosystems. The succession of algae is closely related to the metabolism and structural succession of bacterial populations in the water column. Thus, in this study, the vertical succession characteristics of phytoplankton and bacteria community structure and their coupling with water quality were investigated during an algal bloom in the Lijiahe Reservoir using high-throughput DNA sequencing and Biolog technologies. The results showed that the Lijiahe Reservoir was in the thermal stratification stage in August, and the pH, dissolved oxygen, and NH4+-N of the water column gradually decreased with depth (P<0.001). Algal cell concentration and chlorophyll a exhibited a simultaneous trend (P<0.001), and the maximum values in the surface layer were 3363.33×104 cells·L-1 and 7.03 µg·L-1, respectively. The algal community structure was dominated by Microcystis at water depths of 0 m and 3 m, and at 6 m water depth, Cyclotella replaced Microcystis as the most dominant algae, with a relative abundance of 57.28%. Biolog analysis indicated that the outbreak of Microcystis had a significant impact on bacterial metabolic activity and its relative abundance, but the diversity of bacterial population metabolic activity varied less. A total of 1420 operational taxonomic units were found by high-throughput sequencing, belonging to 10 bacterial phyla. Of these, Actinobacteria and Proteobacteria dominated in all water layers, and their relative abundances were more than 50%. The relative abundance of Chlorobi and Planctomycetes varied significantly with water depth, reaching their maxima at a depth of 6 m with values of 10.29% and 6.78%, respectively, which were both negatively correlated with algal density (P<0.05). Firmicutes and Gemmatimonadetes were positively correlated with algal density (P<0.05). A heat map fingerprint showed that the vertical distribution of the bacterial community structure of the Lijiahe Reservoir varied significantly, and with the increase in water depth, the bacterial community was more uniformly distributed and tended to diversify. Redundancy analysis (RDA) showed that the vertical distribution of the bacterial and algal community structure was regulated by different water qualities, and the difference was significant. This study investigated the coupling mechanism of algal and bacterial communities during the algal bloom in the Lijiahe Reservoir, and the results provided a scientific basis for the investigation of the molecular microecological driving mechanism of water-source algal blooms.

Metabolic Functional Community Diversity of Associated Bacteria during the Degradation of Phytoplankton from a Drinking Water Reservoir.

In the drinking water reservoir ecosystem, phytoplankton and bacteria play important roles in shaping freshwater health and function. In this work, the associated bacterial community functional diversity during degradation of phytoplankton was determined using the substrate utilization profiling (BIOLOG) technique, meanwhile, the composition and concentration of phytoplankton were examined using a microscope. The results indicated that Euglena decreased 58.33% from 0 to 38 d, while the smallest degradation of Bacillariophyta was 20.19%. Average well color development (AWCD590nm) increased during the static periods from 0 to 38 d; however, the AWCD590nm of 18 and 38 d had no significant difference (p ＜ 0.05). The Simpson's index (D) was in accordance with Shannon's diversity (H) and species richness(S); it was measured to be18 > 38 > 5 > 0d. There were significant differences in the pattern and level of carbon sources used by the phytoplankton-associated bacteria. In addition, the principle component analyses (PCA) suggested that the first principle component (PC1) and the second principle component (PC2) explained 46.76% and 21.49% of the total variation for bacterial community, respectively. Redundancy analysis (RDA) revealed that cell abundance of phytoplankton was negatively correlated with the AWCD590nm, amino acids and other functional indexes. Therefore, the data suggest that there are differences in the phytoplankton-associated bacterial community functional diversity during different static stages of water samples collected from the drinking water reservoir.

[Vertical Distribution of Fungal Community Composition and Water Quality During the Deep Reservoir Thermal Stratification].

Freshwater fungal community composition plays pivotal roles in sustaining the function and health of drinking water reservoir ecosystems. To investigate the vertical evaluative characteristics of an aquatic fungal community under conditions of stable thermal stratification, water samples were collected at 0.5, 10, 25, 40, 60 and 70 m depths of Jinpen Reservoir during thermal stratification. Fungal community composition was determined using a high-throughput DNA sequencing technique and combined with water quality parameters. The results showed that the epilimnion, metalimnion, and hypolimnion water layers were formed in Jinpen Reservoir. The temperature decreased steadily from the surface at 22.33℃ to the bottom with 7.21℃ (P<0.05). The dissolved oxygen (DO) concentration decreased significantly from the surface to the bottom (P<0.05). The conductivity and the concentration total phosphorus and iron increased significantly from the surface to the bottom (P<0.05). The high-throughput DNA sequencing revealed a total of 1247 operational taxonomic units (OTUs), which were affiliated with four phylum, 14 classes, and 39 genera, including Zygomycota, Basidiomycota, Ascomycota, and Chytridiomycota. The highest Shannon diversity and Chao 1 were 3.45 and 360 at 60 m, respectively. The Shannon diversity and Chao 1 were significantly higher in the hypolimnion than in the metalimnion (P<0.05). Rhodotorula (27.23%), Alternaria (24.28%),Cladosporium (22.98%), Alternaria (32.00%), Didymella (17.47%), and Cladosporium (28.17%) were the dominant species at 0.5 m, 10 m, 25 m, 40 m, 60 m, and 70 m, respectively. There are a number of unclassified fungi at different water depths. The heat map profile indicated significant differences in the vertical distribution of the fungal community composition in Jinpen Reservoir. A principle component analysis (PCA) indicated that water temperature, DO, TP, and conductivity had dramatic influences on the vertical distribution of the fungal community composition. The results provide new insights on the relationship between water quality and fungal community composition during reservoir thermal stratified periods.

[Denitrification Characteristics and Community Structure of Aerobic Denitrifiers from Lake and Reservoir Sediments].

The effect of aerobic denitrifying bacteria is a hot topic in the field of water environment bioremediation. Aerobic denitrifier communities, H-30, X-10, and C-30, enriched by intermittent aeration, screened with screening culture media, and treated by ultrasonic waves, could perform high denitrification performance at the higher dissolved oxygen concentration of (7.2±0.6) mg ·L-1. The total nitrogen (TN) removal rate of aerobic denitrifier communities, H-30, X-10, and C-30, reached 83.04%, 83.40%, and 82.68%, respectively. There is lower nitrite accumulation during the process of denitrification. Illumina high-throughput DNA sequencing revealed that aerobic denitrifier compositions were significantly different among the three communities. The predominant strains of aerobic denitrifier communities, H-30, X-10, and C-30, were Bacillus subtilis, Paracoccus pantotrophus, and Pseudomonas stutzeri, respectively. The proportion of P. stutzeri in aerobic denitrifier communities H-30 and X-10 was almost the same, while Pseudomonas xiamenensis was only detected in H-30. These three efficient aerobic denitrifier communities provide a bacterium source guarantee for polluted water bioremediation of lakes and reservoirs in cities.

[Denitrification Characteristics and Functional Genes of Denitrifying Bacteria Under Aerobic or Anaerobic Conditions].

An efficient aerobic denitrifying bacterium was isolated from the sediments of the Jin Pen Reservoir in Xi'an. The strain was identified by morphological features and 16S rDNA sequences as Pseudomonas stutzeri and named it KK99. The denitrification characteristics of the strain and the expression level of the functional genes narG, nirS, and nosZ in aerobic/anaerobic conditions were investigated. The results showed that the strain can carry out both anaerobic and aerobic denitrification and has a high efficiency of denitrification, which occurs under both aerobic and anaerobic conditions; after 24 h, the removal rates of total nitrogen (TN) were 85.08% and 89.05%, respectively. Under both the conditions, the expression levels of the functional genes nosZ and nirS are high. nosZ plays a vital role in denitrification in the aerobic pathway, nirS plays a vital role in denitrification in the anaerobic pathway, and narG expression is low under both the conditions. At the same time, simultaneous nitrification and denitrification (SND) capacity of the strain was observed when nitrate and ammonium salts were the nitrogen sources, with the total nitrogen removal rate being 76% within 24 h in aerobic conditions. The P. stutzeri KK99 strain can be used for controlling eutrophication of micro-polluted water, and the application of total nitrogen reduction engineering.

Preparation and Visible-Light Driven Photocatalytic Properties of CuS/Reduced Graphene Oxide Composites.

The CuS/RGO composites were prepared using a facile one-step solvothermal method. The asobtained samples were characterized by X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Brunner-Emmet-Teller (BET) measurements and UV-Vis spectrophotometry. The results showed that the CuS particles were uniformly dispersed on the surface of RGO and electronic migration effect existed between RGO and CuS. The photocatalytic activity of CuS/RGO composites was evaluated by the degradation of Cationic blue SD-BL, Cationic red X-5GN, Direct blue 86, Reactive blue KN-R, Methylene blue and Rhodamine B under visible light irradiation. The photocatalytic experiments showed that the CuS/RGO composites exhibited a better photocatalytic performance for organic dyes with absence of hydrogen peroxide (H2O2) due to the inhibition of recombination of electron-hole pair induced on the surface of CuS. The photodegradation ratio of Cationic blue SD-BL, Cationic red X-5GN, Direct blue 86, Reactive blue KN-R, Methylene blue and Rhodamine B increased to 100%, 95.8%, 99.5%, 87.8%, 100%, 81% after 75 min of irradiation, respectively. Moreover, no significant decline of CuS/RGO photocatalyst for photodegradation of dyes was observed after five cycles, indicating better photostability of the samples. Thus, the CuS/RGO composites could have a promising application in wastewater treatment.

Influenza D Virus in Animal Species in Guangdong Province, Southern China.

Molecular tests revealed influenza D viruses of D/OK lineage widely circulating in farmed animal species in Guangdong Province, southern China. In particular, we found high levels of influenza D virus infection in goats and pigs. We also detected viral RNA in serum specimens and feces of animals with certain severe diseases.

A case report of the orbit, ocular association and the lung in granulomatosis with polyangiitis: A diagnostic challenge.

Granulomatosis with polyangiitis (GPA) is a systemic form of vasculitis that involves small to medium sized vessels and is associated with high morbidity and mortality. GPA presents a continuous and difficult clinical diagnostic concern, due to the rarity of the disease and the diversity of the manifestations. This case report discusses the unusual symptoms presented by a particular patient, discusses these manifestations and explains how the final diagnosis was identified as GPA. A 40-year old Chinese woman was initially referred to the present institution for a progressive worsening pain, redness and gradual decrease in visual acuity in the eyes over the past 7-year period. Previous therapeutic interventions included noncompliant topical and intravenous dexamethasone for 6 years. A pre-operative examination conducted in a differing hospital to search for the presence of an orbital mass, resulted in the identification of an asymptomatic space-occupying lesion in the right middle lung, which was surgically removed in March 2015. A total of four weeks later, surgery was then applied to remove a left orbital mass, in the same hospital. A total of three months later, the patient was diagnosed with peripheral ulcerative keratitis associated with GPA, at the present institution. The corneal lesions were then treated bilaterally with cryotherapy and oral prednisone and cyclophosphamide were administered. Following surgery, the condition of the eyes appeared to be stable. A total of seven months later, the redness and pain of the right eye recurred, followed by a deep lamellar keratoplasty for the treatment of necrotizing scleritis. The condition of the two eyes was subsequently observed to be stable during the nine month follow-up. The present case study reviews various points to consider in a rare, complicated and potentially blinding case of GPA. GPA must therefore be considered in the differential diagnosis of further inflammatory conditions and tumors. Early diagnosis and an appropriate interdisciplinary approach to management, are required to decrease recurrence and morbidity in patients with GPA-mediated inflammatory ocular disease.

[Water Quality and Diversity of Denitrifier Community Structure of Typical Scenic Water Bodies in Xi'an].

Six micro-polluted landscape water bodies were selected to explore the relationship between water quality and the nirS-Type denitrifier community structure and diversity with an Illumina high-throughput sequencing technique. The results of a physico-chemical analysis of the water bodies showed that the Fengqing Park (FQ) and Laodong Park (LD) water bodies were classified as inferior Ⅴ water quality, the Qujiang Park (QJ), Mutasi Park (MTS), and Xinjiyuan Park (XJY) water bodies were classified as Ⅴ water quality, and the Yongyang Park (YY) water quality was classified as Ⅳ. The TN values varied from 1.21 mg·L-1 to 6.50 mg·L-1, with the lowest value found in YY and the highest in FQ (P<0.05). TP was significantly higher in LD (0.10 mg·L-1) and significantly lower in QJ[0.02 mg·L-1 (P<0.05)]. The NH4+-N in LD was 4.44 times higher than that in QJ and FQ (P<0.01). Illumina high-throughput sequencing revealed that the denitrifier community composition was significantly different among the six water bodies, and Paracoccus sp., Pseudomonas sp., and Rubrivivax sp. were the dominant genus species. A principle component analysis (PCA) indicated that the nirS-Type denitrifier communities of XJY and MTS were mainly regulated by NH4+-N and the permanganate index, LD and FQ were significantly influenced by NO3--N, NO2--N, TN, TP, and DO, and YY was significantly influenced by pH value. Our results showed that nirS-Type denitrifier communities were regulated by different water quality indicators.

Molecular detection and genome characterization of porcine circovirus type 2 in rats captured on commercial swine farms.

Porcine circovirus type 2 (PCV2) is considered the major etiological pathogen of porcine circovirus-associated diseases (PCVADs) in pigs. Recently, PCV2 was also found in non-porcine animals such as cattle, rats, and mice. However, there was no record of PCV2 in rats in China. The goal of this study was to investigate whether PCV2 was present in rats (Rattus norvegicus, RN) on three swine farms, using molecular tools. PCR results showed that 30 of 95 (31.6 %) rat samples were positive for PCV2. Moreover, further genotype analysis suggested that 10 of 30 (33.3 %) were positive for PCV2a, 19 of 30 (63.3 %) were positive for PCV2b, and only one sample (1/30, 3.33 %) was co-infected by PCV2a and PCV2b. To determine the possible origin of PCV2, 60 serum samples were also collected from weaned pigs on those swine farms, and 23 out of 60 samples were positive for PCV2. In addition, two distinct RN-origin and two distinct porcine-origin PCV2 full-length nucleotide sequences were obtained from the farms. Sequence and phylogenetic analysis indicated that they had the highest nucleotide similarity and closest genetic relationships to each other. In this study, we report the infection and genome characterization of PCV2 in rats and compare RN-origin and porcine-origin PCV2 sequences obtained from the same pig farm, revealing possible cross-species transmission of PCV2.

Emergence of reticuloendotheliosis virus in pigeons in Guangdong Province, Southern China.

Reticuloendotheliosis virus (REV), an important immunosuppressive pathogen, has many hosts, including chickens, ducks, geese, turkeys, and wild birds. Clinically, REV may lead to increased susceptibility to other pathogens, resulting in serious tissue damage (especially tumors) and the death of its host. In this study, we encountered a disease outbreak resulting in a large number of deaths of pigeons in Guangdong Province, Southern China. Histopathological analysis revealed apparent tumor-like lesions in multiple organs of pigeons. PCR assays for detection of tumor-associated pathogens (REV, avian leukosis virus, and Marek's disease virus) in poultry revealed the presence of REV sequences only. Moreover, fowlpox virus (FPV) with an insertion of REV long terminal repeat (LTR) sequences was also considered, but it was excluded using a specific PCR assay. To gain more genetic information, two full-length REV genome sequences were determined and found to have the highest nucleotide sequence similarity (99.9 %) and the closest genetic relationship to a vaccine strain (MD-2) and had a more distant genetic relationship (94.3 %) to a duck-origin strain (ATCC-VR775). To confirm the presence of REVs in pigeons, specific-pathogen-free (SPF) chickens and healthy pigeons were inoculated with microfiltered tumor tissue homogenates and were found to be susceptible to infection with REV. To our knowledge, this is the first report of REV in pigeons, and the data suggest that pigeons may be the natural host of REV.

Indoor Heating Drives Water Bacterial Growth and Community Metabolic Profile Changes in Building Tap Pipes during the Winter Season.

The growth of the bacterial community harbored in indoor drinking water taps is regulated by external environmental factors, such as indoor temperature. However, the effect of indoor heating on bacterial regrowth associated with indoor drinking water taps is poorly understood. In the present work, flow cytometry and community-level sole-carbon-source utilization techniques were combined to explore the effects of indoor heating on water bacterial cell concentrations and community carbon metabolic profiles in building tap pipes during the winter season. The results showed that the temperature of water stagnated overnight ("before") in the indoor water pipes was 15-17 °C, and the water temperature decreased to 4-6 °C after flushing for 10 min ("flushed"). The highest bacterial cell number was observed in water stagnated overnight, and was 5-11 times higher than that of flushed water. Meanwhile, a significantly higher bacterial community metabolic activity (AWCD590nm) was also found in overnight stagnation water samples. The significant "flushed" and "taps" values indicated that the AWCD590nm, and bacterial cell number varied among the taps within the flushed group (p < 0.01). Heatmap fingerprints and principle component analyses (PCA) revealed a significant discrimination bacterial community functional metabolic profiles in the water stagnated overnight and flushed water. Serine, threonine, glucose-phosphate, ketobutyric acid, phenylethylamine, glycerol, putrescine were significantly used by "before" water samples. The results suggested that water stagnated at higher temperature should be treated before drinking because of bacterial regrowth. The data from this work provides useful information on reasonable utilization of drinking water after stagnation in indoor pipes during indoor heating periods.

Vertical Distribution of Bacterial Community Diversity and Water Quality during the Reservoir Thermal Stratification.

Reservoir thermal stratification drives the water temperature and dissolved oxygen gradient, however, the characteristic of vertical water microbial community during thermal stratification is so far poorly understood. In this work, water bacterial community diversity was determined using the Illumina Miseq sequencing technique. The results showed that epilimnion, metalimnion and hypolimnion were formed steadily in the JINPEN drinking water reservoir. Water temperature decreased steadily from the surface (23.11 °C) to the bottom (9.17 °C). Total nitrogen ranged from 1.07 to 2.06 mg/L and nitrate nitrogen ranged from 0.8 to 1.84 mg/L. The dissolved oxygen concentration decreased sharply below 50 m, and reached zero at 65 m. The Miseq sequencing revealed a total of 4127 operational taxonomic units (OTUs) with 97% similarity, which were affiliated with 15 phyla including Acidobacteria, Actinobacteria, Armatimonadetes, Bacteroidetes, Caldiserica, Chlamydiae, Chlorobi, Chloroflexi, Cyanobacteria, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria, and Verrucomicrobia. The highest Shannon diversity was 4.41 in 45 m, and the highest Chao 1 diversity was 506 in 5 m. Rhodobacter dominated in 55 m (23.24%) and 65 m (12.58%). Prosthecobacter dominated from 0.5 to 50 m. The heat map profile and redundancy analysis (RDA) indicated significant difference in vertical water bacterial community composition in the reservoir. Meanwhile, water quality properties including dissolved oxygen, conductivity, nitrate nitrogen and total nitrogen have a dramatic influence on vertical distribution of bacterial communities.

Abundance and diversity of bacteria in oxygen minimum drinking water reservoir sediments studied by quantitative PCR and pyrosequencing.

Reservoir sediment is one of the most stressful environments for microorganisms due to periodically oxygen minimum conditions. In this study, the abundance and composition of bacteria associated with sediments from three drinking water reservoirs (Zhoucun, ZCR; Shibianyu, SBYR; and Jinpen, JPR) were investigated by quantitative polymerase chain reaction and 16S rRNA-based 454 pyrosequencing. The results of physico-chemical analysis of sediments showed that the organic matter and total nitrogen were significantly higher in ZCR as compared to JPR (P < 0.01). The bacterial abundance was 9.13 × 10(6), 1.14 × 10(7), and 6.35 × 10(6) copies/ng DNA in sediments of SBYR, ZCR, and JPR, respectively (P < 0.01). The pyrosequencing revealed a total of 9,673 operational taxonomic units, which were affiliated with 17 phyla. The dominant phylum was Firmicutes (56.83%) in JPR; whereas, the dominance of Proteobacteria was observed in SBYR with 40.38% and ZCR with 39.56%. The Shannon-Wiener diversity (H') was high in ZCR; whereas, Chao 1 richness was high in SBYR. The dominant genera were Clostridium with 42.15% and Bacillus with 20.44% in JPR. Meanwhile, Dechloromonas with 14.80% and Smithella with 7.20% were dominated in ZCR, and Bacillus with 45.45% and Acinetobacter with 5.15% in SBYR. The heat map profiles and redundancy analysis indicated substantial differences in sediment bacterial community composition among three reservoirs. Moreover, it appears from the results that physico-chemical variables of sediments including pH, organic matter, total nitrogen, and available phosphorous played key roles in shaping the bacterial community diversity. The results obtained from this study will broaden our understanding on the bacterial community structure of sediments in oxygen minimum and stressful freshwater environments.

Complete genome characterization and phylogenetic analysis of three distinct buffalo-origin PCV2 isolates from China.

Complete genome characterization of porcine circovirus type 2 (PCV2) for bovid origins was still unclear in China. Therefore, in this study, PCV2 full-length genome of buffalo-origin was amplified and analyzed using PCR, DNAStar and MEGA 5.1. Genome size of three distinct PCV2 strains (buffalo1, buffalo2 and buffalo3) was 1767 bp (48.56% G+C), 1767 bp (48.67% G+C) and 1768 bp (48.08% G+C), respectively. At the nucleotide level, their identity varied from 95% to 96% for complete genome, from 97% to 97.8% for ORF1, and from 90.6% to 94.4% for ORF2. At the amino acid level, their identity varied from 98.7% to 99% for ORF1, and from 88% to 94.9% for ORF2. Online Blast analysis showed that buffalo1, buffalo2 and buffalo3 had highest nucleotide identity (varied from 99.77% to 99.83%) with porcine-origin PCV2 strains. Moreover, in the phylogenetic tree, they were divided into three different clusters and belonged to the worldwide accepted genotypes of PCV2b, PCV2c and PCV2a, respectively. To summarize, this study first recorded complete genome information of PCV2 for non-porcine origins in China.