A comprehensive investigation of the microbial risk of secondary water supply systems in residential neighborhoods in a large city.

Secondary water supply systems (SWSSs) are characterized by long water stagnation and low levels of chlorine residuals, which may pose a high microbial risk to terminal users. In this study, the SWSSs of 12 residential neighborhoods in a metropolitan area of 5 million people in southeastern China were seasonally investigated to assess their microbial risks by determining more than 30 physicochemical and biological parameters. Although the microbiological quality of SWSS water met the requirements of the standards for drinking water quality of China, it did deteriorate in various aspects. The heterotrophic plate counts with R2A media were high (> 100 CFU/mL) in some SWSS tank and tap water samples. Propidium monoazide (PMA)-qPCR revealed a one magnitude higher abundance of viable bacteria in the tank and tap water samples (average 103.63±1.10 and 103.65±1.25 gene copies/mL, respectively) compared with the input water samples, and Enterococcus, Acanthamoeba, and Hartmannella vermiformis were only detected in the tanks. In particular, the high detection frequency of Legionella in 35% tank and 21% tap water samples suggested it is a supplementary microbial safety indicator in SWSSs. The microbial regrowth potential was more obvious in summer, and Illumina sequencing also demonstrated distinct seasonal changes in the relative abundance of bacterial gene sequences at the genus level. Turbidity and residual chlorine were closely connected with total bacterial biomass, and the latter seemed responsible for microbial community structure alteration. The extremely low chlorine residuals associated with a high abundance of total bacteria (as high as 106.48 gene copies/mL) and Legionella (as high as 106.71 gene copies/100 mL) in the closed valve tanks highlighted the high microbial risk increased by mishandling the operation of SWSSs. This study found that SWSSs possessed a higher microbial risk than the drinking water network, which suggested that the frequency and scope of monitoring the microbial risk of SWSSs in megacities should be strengthened for the purpose of waterborne epidemic disease prevention and control.

Combined use of bFGF/EGF and all-trans-retinoic acid cooperatively promotes neuronal differentiation and neurite outgrowth in neural stem cells.

Neural stem cells (NSCs) as sources of new neurons in brain injuries or diseases are required to not only elicit neurons for neuronal repair, but also to enhance neurite outgrowth for neuronal network reestablishment. Various trophic or chemotropic factors have been shown to cooperatively improve NSC neurogenesis. However, effects of combined treatment of all-trans-retinoic acid (RA) with GF (Basic fibroblast growth factor and epidermal growth factor, bFGF/EGF) on neurogenesis of NSCs are poorly understood. To address this question, NSCs were isolated from the forebrains of embryonic mice, and treated with GF and RA either alone or in combination for differentiation in vitro. Neurons and astrocytes differentiated from NSCs were stained for MAP2 and GFAP separately by immunofluorescence. The results indicated that GF displayed superior efficacy in promoting neuronal differentiation, and RA showed better efficacy in advancing neurite outgrowth by increasing both neurite length and number. In addition, higher differentiation efficiency of neurons to astrocytes in RA or GF, or both acted at the early stage. However, more importantly, compared with RA alone, GF and RA in combination enhanced neuronal differentiation. Moreover, the combined use of GF and RA increased the length and number of neurites compared with GF, as well as the relative expression level of Smurf1. In addition, astrocytes induced by GF, RA, or both exhibited a radial glia-like morphology with long processes differing from serum effects, which might in part attribute to the total numbers of neurons. These findings for the first time unveil the roles of combined use of GF and RA on the neurogenesis of NSCs, suggesting that the use of this combination could be a comprehensive strategy for the functional repair of the nervous system through promoting neuronal differentiation, and advancing neurite outgrowth.

TIR-Domain-Containing Adapter-Inducing Interferon-ß (TRIF) Is Essential for MPTP-Induced Dopaminergic Neuroprotection via Microglial Cell M1/M2 Modulation.

Dynamic changes of two phenotypes of microglia, M1 and M2, are critically associated with the neurodegeneration of Parkinson's disease. However, the regulation of the M1/M2 paradigm is still unclear. In the MPTP induced neurodegeneration model, we examined the concentration of dopamine (DA) related metabolites and the survival of tyrosine hydroxylase (TH) positive cells in WT and Trif-/- mice. In in vitro experiments, MN9D cells were co-cultured with BV2 cells to mimic the animal experiments. Inhibition of TRIF aggravated TH+ cell loss, and DA-related metabolites decreased. TRIF inhibition was able to interrupt the microglial M1/M2 dynamic transformation. More BV2 cells were activated and migrated across the membrane of transwell plates by siTRIF treatment. Also, TRIF interruption inhibits the transformation of BV2 cells from the M1 to M2 phenotype which played a beneficial role in neuronal degenerative processes, and increased MN9D apoptosis. Moreover, MPP+ treatment decreases the (DAT) dopamine transporter and TH synthesis by MN9D. Taken together, the current results suggest that TRIF plays a key switch function in contributing to the microglial M1/M2 phenotype dynamic transformation. The interruption of TRIF may decrease the survival of MN9D cells as well as DAT and TH protein production. The current study sheds some light on the PD mechanism research by innate inflammation regulation.

Spatial and Temporal Distribution of Dopaminergic Neurons during Development in Zebrafish.

As one of the model organisms of Parkinson's disease (PD) research, the zebrafish has its advantages, such as the 87% homology with human genome and transparent embryos which make it possible to observe the development of dopaminergic neurons in real time. However, there is no midbrain dopaminergic system in zebrafish when compared with mammals, and the location and projection of the dopaminergic neurons are seldom reported. In this study, Vmat2:GFP transgenic zebrafish was used to observe the development and distribution of dopaminergic neurons in real time. We found that diencephalons (DC) 2 and DC4 neuronal populations were detected at 24 h post fertilization (hpf). All DC neuronal populations as well as those in locus coeruleus (LC), raphe nuclei (Ra) and telencephalon were detected at 48 hpf. Axons were detected at 72 hpf. At 96 hpf, all the neuronal populations were detected. For the first time we reported axons from the posterior tubercle (PT) of ventral DC projected to subpallium in vivo. However, when compared with results from whole mount tyrosine hydroxylase (TH) immunofluorescence staining in wild type (WT) zebrafish, we found that DC2 and DC4 neuronal populations were mainly dopaminergic, while DC1, DC3, DC5 and DC6 might not. Neurons in pretectum (Pr) and telencephalon were mainly dopaminergic, while neurons in LC and Ra might be noradrenergic. Our study makes some corrections and modifications on the development, localization and distribution of zebrafish dopaminergic neurons, and provides some experimental evidences for the construction of the zebrafish PD model.

[Composition and distribution patterns of rare earth elements in Fujian teas].

OBJECTIVE: To investigate the composition and distribution pattern of rare earth elements in the teas from Fujian province. METHODS: A total of 145 samples of nine varieties of the teas were collected from their plantation fields and markets in Fujian province. The concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y in the samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). RESULTS: The concentrations of total REEs, light REEs (LREEs) and heavy REEs (HREEs) in the teas were 2.483, 1.764, 0.720 mg/kg, respectively. The LREE was dominant with the highest concentration of Ce. The distribution pattern of the REE contents in the teas and corresponding plantation soils were similar. CONCLUSION: After the chondrite-nomalized distribution treatment, it was found that the REEs in the Fujian teas had a similar pattern with those of the soils in the Fujian province and Mainland China, and also with those in the green tea from Jiangsu province. However, the high concentrations of REEs in some Fujian teas should be paid with more attention and investigation.

Serial foodborne norovirus outbreaks associated with multiple genotypes.

Noroviruses (NoV) have been recognized as an important pathogen associated with acute gastroenteritis worldwide during the past three decades. In the spring of 2012, a series of foodborne outbreaks in tourist groups were reported to Xiamen Center for Disease Control and Prevention, Xiamen, Fujian province, China. Among a total of 268 tourists in 7 groups, the prevalence rate of acute gastroenteritis was 16.0% (43/268). Twenty-three feces or anal swabs were collected for laboratory tests of causative agents, no bacterial pathogen was identified, while 22 of them were positive for NoV RNA. In addition, thirteen NoV fragments were recovered from positive specimens and sequenced, belonging to five genotypes such as GI.3, GI.4, GII.4, GII.6, and GII.14, respectively. However, NoV fragments obtained from locally infected patients showed distinct genotypes. Therefore, epidemiological investigation and laboratory analyses demonstrated that the serial foodborne NoV outbreaks in tourists were co-infection of multiple genotypes induced acute gastroenteritis linked to a restaurant.

[Morphological research on brain development and expression of vital cytokines in brain of human 6-8 week old embryo aborted for unexpected cause].

OBJECTIVE: To clarify the changes in cell proliferation, differentiation, apoptosis and in the expression of vital cytokines during development of 6-8 week old embryo, and hence provide the evidence for identifying the mechanisms of cell proliferation, differentiation, apoptosis during early developing human embryonic brain. METHODS: Human aborted embryos were obtained with the consents signed by the pregnant women with unexpected abortions in gestation of 6-8 weeks. The histochemical SABC method and TUNEL Staining were employed to this research project. RESULTS: At 6 weeks, two telencephalons, diencephalon, mesencephalon, metencephalon, and myelencephalon have been formed, and from week 6 to 8, every cerebral vesicle has had three layer cells including germinal layer (GL), intermediate layer ( IL ), and marginal zone (MZ). At 6-7 weeks, TUNEL-labeled cells and PCNA-, Bcl-2-, Bax-, Fas-, Fas-L-, Rb- and P53-positive cells were all observed in the GL and IL of the five brain regions, positive deposition appeared in nuclei. At week 8, Fas- and Rb-positive cells were observed in the IL of the five brain regions, positive deposition appeared in cytoplasm and cell processes, and no changes in the distributions of TUNEL-labeled cells and positive cells regarding the other five factors. The expressions of the cytokines were in agreement with the occurrence of the neuronal proliferation and apoptosis temporally and in space. CONCLUSION: During development in early embryo brain, neural precursor cell proliferation and apoptosis occur simultaneously. Fas, FasL and Bax may be involved in the induction of cell apoptosis. Bcl-2 probably prevents the cell apoptosis and provides a survival signal for cells. Rb and P53 may play a critical role in monitoring and maintaining the normal neural precursor cell to proliferation and differentiation.

[Expression of CD34, CD14, CD10, CD31 and factor VIII on hematopoietic cells of yolk sac blood island, AGM region and liver of human embryo and fetus].

OBJECTIVES: To study the expression of CD34, CD31, CD14, CD10 and factor VIII on blood island of yolk sac (YS), PAS/aorta-germen-mesonephros (AGM) region and hepatic hematopoietic foci. METHODS: Thirty-two cases of 3rd-12th weeks human embryo were obtained by drug abortion. Paraffin embedded sections with H.E staining and immunohistochemistry reaction (SABC) were performed. RESULTS: YS blood island of 3rd-4th weeks of gestation was consisted of two types of cells. One was vascular endothelial cells located outside and the other hematopoietic cells inside the blood island. Both the two types of cells were CD10, CD14, CD31 and factor VIII positive. Hematopoietic cells were CD34 negative, and vascular endothelial cells were CD34 positive. On 32nd days of gestation, the hematopoietic cells migrated out of YS. On 4th week of gestation, CD34, CD14, CD10, CD31 and factor VIII positive cells appeared in the aorta, mesonephros and hepatic hematopoietic foci. By the 7th week, the number of positive hematopoietic cells reached the peak. In 11th-12th weeks, most cells in these regions were matured red blood cells and were negative for all the antibodies mentioned above excepting for CD34. During 4th-12th weeks, all endothelial cells in embryo were CD34 positive. CONCLUSIONS: The hematopoietic cells and endothelial cells of YS blood island co-expressed CD10, CD14, CD31 and factor VIII. Endothelial cells were CD34 positive but hematopoietic cells were negative in YS blood island. The hematopoietic cells of aorta, mesonephros and hepatic hematopoietic foci expressed CD34, CD10, CD14 and factor VIII from 4th week to 7th week. Anti-CD34 antibody could label endothelial cells of every kinds vessels of embryo from 3rd to 12th weeks.

[Expression of HNF4alpha and HNF6 mRNA during the process of mouse liver development].

OBJECTIVE: To investigate the function of HNF4a and HNF6 during liver development. METHODS: The expression levels of HNF4alpha and HNF6 at E8, 9, 13, 15, 17, P1 and in adult mouse liver were detected by RT-PCR and in situ hybridization. RESULTS: RT-PCR results showed that HNF4alpha first expressed at E9, the time of liver bud formation, and lasted through all gestation and existed in adult liver. In situ hybridization showed that the expression of HNF4alpha was detected at the cells of liver cords during various stages of mouse liver development, and there were still a few HNF4alpha positive hepatocytes in adult liver. The cells of bile duct plate and biliary epithelial cells, endothelial cells, hematopoietic cells of liver were negative for HNF4alpha. The expression of HNF6 mRNA was detected in the liver at E9, the time of liver formation onset. Then, HNF6 mRNA disappeared transiently at E13, but it appeared again at E15. Its expression lasted until adult. In situ hybridization studies showed that most liver cord cells were positive for HNF6 at E9 and E15. At E17 and P1, the expression levels of liver cord cells declined, and HNF6 strongly expressed in the cells of bile duct plate and biliary epithelial cells. CONCLUSION: HNF4alpha could modulate the formation of liver bud, trigger the differentiation of hepatic stem cell towards hepatocytes, and keep the shape of hepatocytes. HNF6 might play a role at the onset of liver development, in the differentiation of hepatic stem cell towards biliary epithelial cells, and in maintaining the morphological characteristic of biliary epithelial cells.

[Expression of VEGFA, VEGFC, angiopoietin-1, angiopoietin-2 and their receptors on development liver during gestation of weeks 3-12 of human embryo].

The aim was to study the expression of VEGF-A, VEGF-C, angiopoietin-1, angiopoietin-2 and their receptors on development liver during gestation of weeks 3-12 of human embryo. Human embryo contingently aborted at 3-12 weeks of gestation were collected with signed agreements of the pregnant women suffered from accidental abortions. The specimens were fixed by 4% paraformaldehyde and embedded by paraffin. 5 microm serial sections were made. HE staining, immunohistochemistry method and light-microscope were employed. The results showed that at 4-5 weeks of development, liver was constituted by a few hepatic cords. Hematopoietic cell or blood cells were undetectable in the 4 week of gestation. A few cells which were larger, rounded and nucleared cells appeared and expressed VEGFA, flt-4 and Tie-2 proteins strongly in liver at 5 weeks of gestation. The number of these immuno-positive cells was highest in the 7th week and decreased at 11-12 weeks of gestation. These cells expressed flk-1 transiently in the 6th week. VEGF-C and flt-1 were expressed by hepatic cells from weeks 7 to 12 of gestation. The immuno-positive products were deposited in plasma of hepatic cells. Angiopoietin-1, angiopoietin-2 and Tie-2 were detectable on those cells which expressed VEGFA, flt-4 and Tie-2 from weeks 5 to 12 of gestation. The expression of angiopoietin-1 and angiopoietin-2 were weakly and Tie-2 was strongly. They were expressed weakly too by hepatic cells at 5 to 12 weeks of gestation. All factors and their receptors were undetectable on vascular endothelial cells at 4-12 weeks of gestation. It is concluded that the expression patterns of VEGF family on cells of liver are different before and after 7 weeks of gestation. The hematopoiesis in fetal liver may be related to development of hepatic cell.

[Expression of VEGFA, VEGFC, angiopoietin-1, angiopoietin-2 and their receptors on yolk sac blood island, aorta-gonad-mesonephros (AGM) region of human embryo].

The study was to investigate the expression of VEGFA, VEGFC, angiopoietin-1, angiopoietin-2 and their receptors on yolk sac blood island, AGM region during gestation of 3th-12th weeks of human embryo. Human embryo contingently aborted at 3 - 12 weeks of gestation were collected with signed agreements of the pregnant women suffered from accidental abortions. The specimens were fixed by 4% paraformaldehyde and embedded by paraffin. 5 micro m serial sections were made. HE and immunohistochemistry method (SABC) and light-microscope were employed. The results showed that VEGFA and its receptors flt1/flk-1, VEGFC and its receptor flt-4, angiopoietin-2 and its receptor tie-2 proteins were expressed strongly and angiopoietin-1 was weakly expressed by hematopoietic cells and vascular endothelial cells of blood island at 21 and 25 days of gestation. In the 4th week of gestation, immuno-positive reaction of these factors and their receptors appeared in the aorta and mesonephros deposited in larger, rounded and nucleated cells which represented hematopoietic cells. Up to 7th week, positive hematopoietic cells in the regions were much abundant. The number of positive cells decreased at 8th week. Up to 12th week, almost all blood cells were immuno-negative. VEGFA, flt-1, flt-4, angiopoietin-1, angiopoietin-2 and Tie-2 protein were expressed mainly by gonad at 6 - 8 weeks, but it did not express VEGFC and flk-1. The immuno-reaction of the factors and their receptors could not detected in vascular endothelial cells during 3-12th weeks of gestation. It is concluded that hematopoietic cells and endothelial cells in blood island of yolk sac, mesonephros and dorsal aorta co-expressed some factors and their receptors in relation to vasculogenesis and hematopoiesis. Intraembryonic hematopoiesis began in the 4th week of gestation.

[The characteristics of hepatic stem cells and the expression of growth factor and their receptors in the early embryonic human liver].

To study the morphological characteristics of hepatic stem cells and the expression of HGF, IGF-I, TGFbeta1 and their receptors in human embryonic livers at 3-5 weeks of gestation. The SABC immunohistochemical method with HE counterstaining was employed. We found that the hepatic bud formed at the end of the 3rd week. At the 4th week, the cells of hepatic bud migrated into the septum transversum mesenchyme and formed the hepatic cords. The hepatic cells at 3-4 weeks displayed the typical characteristics of immature cells: small size, a round or ovoid nucleus with dark color, scant cytoplasm with slight blue and a high ratio of nuclei/cytoplasm. They were positive for alpha-Fetoprotein (AFP), c-Met and negative for cytokertin 19 (CK19), and proliferating cell nuclear antigen (PCNA). At the 5th week, compared to those at the 4th week, the number of cells within the hepatic cords increased. But the cells at the 5th week were homogeneous and displayed the typical characteristic of immature cells. Those cells began to express PCNA at the 5th week. The hepatic cells at the 5th week were positive for insulin-like growth factor I (IGF-I), transforming growth factor beta1 (TGFbeta1) and their receptors, and were negative for hepatocyte growth factor (HGF), while HGF were positive in the cardiac cells and septum transversum mesenchyme. The results indicated that the cells of hepatic bud and cords were the hepatic stem cells. The difference of morphology and proteins expression at 3-5 weeks of gestation inferred that those stem cells belong to different developmental stage. AFP and c-Met were the markers of hepatic stem cells at the early stage of human embryo. HGF, IGF-I, TGFbeta1 and their receptors may involve in regulating the development of early embryonic human liver.