Can public-private partnerships (PPPs) improve the environmental performance of urban sewage treatment?

Insufficient sewage treatment facility is one important reason for wastewater entering and affecting aquatic ecosystems. The PPP mode, serving as one of the fastest-growing mechanisms for public service provision in recent decades, is considered to be an effective way to alleviate the pressure of funding shortages and to improve the efficiency of sewage treatment. However, the performance of PPPs has been questioned, especially the service quality given the inherent nature of the private sectors' pursuit of maximizing economic profit and the shortcoming of incomplete contracts. This paper evaluates the service quality, namely the environmental performance, of the PPP mode in China's urban sewage treatment sector. Based on detailed firm-level data in Jiangsu Province, China, we find that the PPP mode has improved the pollutant treatment performance, and increased operation cost and promoted sewage treatment efficiency serve as the main mechanism for the improvement of environmental performance. The research findings could help both developed and developing countries to apply and design a public-private partnerships mechanism.

[Detection of CRSPR-Cas system in Streptococcus thermophiles].

Objective: We aimed to detect the CRSPR-Cas system of six Streptococcus thermophilus. Methods: Bioinformatics method was used to predict CRSPR-Cas system of nine S. thermophilus that published in National Center for Biotechnology Information. Four primers were designed according to the flanking sequences of standard strains and the CRISPR-Cas system of six S. thermophilus have been detected by PCR method. Results: S. thermophilus S4 had a Cas9 gene, others all had Cas9 gene, Cas10 gene and Cas9* gene. In addition, 79 and KLDS3.0207 still had Cas3 gene. Conclusion: Signature genes amplification of CRSPR-Cas system could predict the type of CRSPR-Cas system in unsequenced strains, these findings will help establish the foundation for the study of CRSPR-Cas system in lactic acid bacteria.

Infant formula supplemented with low protein and high carbohydrate alters the intestinal microbiota in neonatal SD rats.

BACKGROUND: Infant microbiota is influenced by numerous factors, such as delivery mode, environment, prematurity and diet (breast milk or formula) and last but not least, the diet composition. In the diet composition, protein and carbohydrate are very important for the growth of microbiota, many infant fomulas (different ratio protein/carbohydrate) can regulate the development of gut microbiota by different metabolism. The effect of low-protein, high-carbohydrate infant formula on the establishment of microbiota remains unclear, and the effect of human breast milk on the gut microbiota of the rats has also not been reported. RESULTS: In a 7 d intervention, a total of 36 neonatal SD rats (14 d old) were randomly assigned to the following groups: (1) breast-fed group (A group); (2) low-protein, high-carbohydrate infant formula-fed group (B group); (3) human breast milk-fed group (C group). After 7 days, we selected 6 rats at random from each group to study. Microbial composition in the contents of the large intestines was analysed by Miseq Sequencing. Significantly different (p<0.05) microbial colonisation patterns were observed in the large intestines of breast-fed group from low-protein, high-carbohydrate infant formula-fed and human breast milk-fed rats, but the microbiota of low-protein, high-carbohydrate infant formula-fed group and human breast milk-fed group have high similarity. At the phylum level, the absolute quantity of Bacteroidetes, Firmicutes and Proteobacteria (p<0.001) significantly differentiated in breast-fed group from low- protein, high- carbohydrate infant formula-fed and human breast milk-fed groups. Lachnospiraceae, Bacteroidaceae, Porphyromonadaceae and Prevotellaceae were the 4 top families in breast-fed group, but the top 4 families in low-protein, high- carbohydrate infant formula-fed and human breast milk-fed groups were the same, which were Bacteroidaceae, Enterobacteriaceae, Porphyromonadaceae and Lachnospiraceae. At the genus level, Bacteroides was the most abundant division, their OTUS abundance in three groups was 14.91%, 35.94%, 43.24% respectively. CONCLUSIONS: This study showed that infant formula closer resembling human milk was more different than rats' breast milk and led to a microbiota profile similar to that for human breast milk-fed neonates. The finding could support a new thinking to develop infant formulas, and provide much more details than what is known previously.

A DNA phosphorothioation-based Dnd defense system provides resistance against various phages and is compatible with the Ssp defense system.

DndABCDE-catalyzed DNA phosphorothioation (PT), in which the nonbridging oxygen is swapped with a sulfur atom, was first identified in the bacterial genome. Usually, this modification gene cluster is paired with a restriction module consisting of DndF, DndG, and DndH. Although the mechanisms for the antiphage activity conferred by this Dnd-related restriction and modification (R-M) system have been well characterized, several features remain unclear, including the antiphage spectrum and potential interference with DNA methylation. Recently, a novel PT-related R-M system, composed of the modification module SspABCD paired with a single restriction enzyme, SspE, was revealed to be widespread in the bacterial kingdom, which aroused our interest in the interaction between Dnd- and Ssp-based R-M systems. In this study, we discussed the action of Dnd-related R-M systems against phages and demonstrated that the host could benefit from the protection provided by Dnd-related R-M systems against infection by various lytic phages as well as temperate phages. However, this defense barrier would fail against lysogenic phages. Interestingly, DNA methylation, even in the consensus sequence recognized by the Dnd system, could not weaken the restriction efficiency. Finally, we explored the interaction between Dnd- and Ssp-based R-M systems and found that these two systems were compatible. This study not only expands our knowledge of Dnd-associated R-M systems but also reveals a complex interaction between different defense barriers that coexist in the cell. IMPORTANCE Recently, we decoded the mechanism of Dnd-related R-M systems against genetic parasites. In the presence of exogenous DNA that lacks PT, the macromolecular machine consisting of DndF, DndG, and DndH undergoes conformational changes to perform DNA binding, translocation, and DNA nicking activities and scavenge the foreign DNA. However, several questions remain unanswered, including questions regarding the antiphage spectrum, potential interference by DNA methylation, and interplay with other PT-dependent R-M systems. Here, we revealed that the host could benefit from Dnd-related R-M systems for a broad range of antiphage activities, regardless of the presence of DNA methylation. Furthermore, we demonstrated that the convergence of Dnd- and Ssp-related R-M systems could confer to the host a stronger antiphage ability through the additive suppression of phage replication. This study not only deepens our understanding of PT-related defense barriers but also expands our knowledge of the arms race between bacteria and their predators.

Cytosine-phosphate-guanine oligodeoxynucleotides regulate the cell cycle, apoptosis, and steroidogenesis of mouse ovarian granulosa cells by targeting inhibin alpha (1 ~ 32) fragments.

Cytosine-phosphate-guanine oligodeoxynucleotides (CpG-ODNs), which exist in vertebrate, bacterial, and viral genomes, are regarded as strong immune adjuvants. To date, the biological activities of CpG-ODNs in reproduction remain unknown. Here, we investigated the effects of CpG-ODNs on the cell cycle, apoptosis, and steroidogenesis in mouse granulosa cells (mGCs), in combination with inhibin alpha (1 ~ 32) fragments. mGCs were transfected with pEGFP (containing green fluorescent protein, as a control), pEGISI (containing inhibin alpha (1 ~ 32) fragments), or pEGISI-CpG-ODNs (containing inhibin alpha (1 ~ 32) fragments and CpG-ODNs motifs) plasmid for 48 h in vitro. Our results showed that the mRNA and protein expression levels of inhibin alpha were downregulated in mGCs transfected with pEGISI-CpG-ODNs, compared to those transfected with pEGISI. Flow cytometry demonstrated that pEGISI-CpG-ODNs transfection promoted cell proliferation (for example, increasing the number of cells in S and G2 phases) and decreased apoptosis, compared to pEGISI transfection. The present study also indicated that the expression of cell cycle-related genes (cyclin D2, cyclin D3, cyclin E1, Cdk2, and Cdk6) was increased, while the expression of apoptosis-related factors (Fas, FasL, caspase-8, and caspase-3) decreased after pEGISI-CpG-ODNs treatment. Additionally, pEGISI-CpG-ODNs reversed the effect of pEGISI on the secretion of estradiol in mGCs, which was further validated by upregulating the levels of its synthesis-related factors (StAR, Cyp11a1, and 17ß-HSD II). Nevertheless, pEGISI-CpG-ODNs or pEGISI did not affect the concentration of progesterone nor changed the expression levels of its synthesis-related factors (3ß-HSD I and Cyp19a1). In conclusion, this study demonstrated that CpG-ODNs may affect the cell cycle, apoptosis, and steroidogenesis by targeting the effects of inhibin alpha (1 ~ 32) fragments, supporting the potential role of CpG-ODNs in the development of granulosa cells.

A central circadian oscillator confers defense heterosis in hybrids without growth vigor costs.

Plant immunity frequently incurs growth penalties, which known as the trade-off between immunity and growth. Heterosis, the phenotypic superiority of a hybrid over its parents, has been demonstrated for many traits but rarely for disease resistance. Here, we report that the central circadian oscillator, CCA1, confers heterosis for bacterial defense in hybrids without growth vigor costs, and it even significantly enhances the growth heterosis of hybrids under pathogen infection. The genetic perturbation of CCA1 abrogated heterosis for both defense and growth in hybrids. Upon pathogen attack, the expression of CCA1 in F1 hybrids is precisely modulated at different time points during the day by its rhythmic histone modifications. Before dawn of the first infection day, epigenetic activation of CCA1 promotes an elevation of salicylic acid accumulation in hybrids, enabling heterosis for defense. During the middle of every infection day, diurnal epigenetic repression of CCA1 leads to rhythmically increased chlorophyll synthesis and starch metabolism in hybrids, effectively eliminating the immunity-growth heterosis trade-offs in hybrids.

Prototype of an Interface for Hyphenating Distillation with Gas Chromatography and Mass Spectrometry.

Chemical analysis of complex matrices-containing hundreds of compounds-is challenging. Two-dimensional separation techniques provide an efficient way to reduce complexity of mixtures analyzed by mass spectrometry (MS). For example, gasoline is a mixture of numerous compounds, which can be fractionated by distillation techniques. However, coupling conventional distillation with other separations as well as MS is not straightforward. We have established an automatic system for online coupling of simple microscale distillation with gas chromatography (GC) and electron ionization MS. The developed system incorporates an interface between the distillation condenser and the injector of a fused silica capillary GC column. Development of this multidimensional separation (distillation-GC-MS) was preceded by a series of preliminary off-line experiments. In the developed technique, the components with different boiling points are fractionated and instantly analyzed by GC-MS. The obtained data sets illustrate dynamics of the distillation process. An important advantage of the distillation-GC-MS technique is that raw samples can directly be analyzed without removal of the non-volatile matrix residues that could contaminate the GC injection port and the column. Distilling the samples immediately before the injection to the GC column may reduce possible matrix effects-especially in the early phase of separation, when molecules with different volatilities co-migrate. It can also reduce losses of highly volatile components (during fraction collection and transfer). The two separation steps are partly orthogonal, what can slightly increase selectivity of the entire analysis.

Probiotic properties of Enterococcus strains isolated from traditional naturally fermented cream in China.

The purpose of this study was to evaluate the probiotic properties of Enterococcus strains isolated from traditional naturally fermented cream in China. Four Enterococcus isolates showed high cholesterol removal ability in media were identified as Enterococcus durans (KLDS 6.0930 and 6.0933) and Enterococcus faecalis (KLDS 6.0934 and 6.0935) by 16S rRNA and pheS gene sequences, respectively, and selected for further evaluation. In order to assess the probiotic potential and safety of these strains, the property of four Enterococcus strains were examined, including acid and bile tolerance, adherence to Caco-2 cells and antibiotics susceptibility. All four strains showed potential cholesterol assimilation, de-conjugation of bile salts and/or cholesterol degradation to remove cholesterol in vitro. In addition, the potential effect of E. durans KLDS 6.0930 on serum cholesterol levels was evaluated in Sprague-Dawley rats. After 4 weeks administration, compared with rats fed a high-cholesterol diet without lactic acid bacteria supplementation, there was a significant (P < 0.05) decrease in the total cholesterol and low-density lipoprotein cholesterol levels in the serum of rats treated with KLDS 6.0930. Furthermore, total bile acid level in the feces was significantly (P < 0.05) increased after KLDS 6.0930 administration. These observations suggested that the strain E. durans KLDS 6.0930 may be used in the future as a good candidate for lowering human serum cholesterol levels.

Capillary hydrodynamic chromatography reveals temporal profiles of cell aggregates.

Microbial cells are known to form aggregates. Such aggregates can be found in various matrices; for example, functional drinks. Capillary hydrodynamic chromatography (HDC) enables separation of particles by size using nanoliter-scale volumes of samples. Here we propose an approach based on HDC for characterisation of real samples containing aggregated and non-aggregated bacterial and fungal cells. Separation of cells and cell aggregates in HDC arises from the parabolic flow profile under laminar flow conditions. In the presented protocol, hydrodynamic separation is coupled with different on-line and off-line detectors (light absorption/scattering and microscopy). The method has successfully been applied in the monitoring of dynamic changes in the microbiome of probiotic drinks. Chromatographic profiles of yogurt and kefir samples obtained at different times during fermentation are in a good agreement with microscopic images. Moreover, thanks to the implementation of an area imaging detector, capillary HDC could be multiplexed and used to profile spatial gradients in cell suspensions, which arise in the course of sedimentation of cells and cell aggregates. This result shows compatibility of sedimentation analysis and capillary HDC. We believe that the approach may find applications in the profiling of functional foods and other matrices containing aggregated bioparticles.

Complete genome sequence of Lactobacillus helveticus KLDS1.8701, a probiotic strain producing bacteriocin.

This study investigated the functional diversity of Lactobacillus helveticus KLDS1.8701 by carrying out a whole-genome sequence analyses of L. helveticus KLDS1.8701. L. helveticus KLDS1.8701 strain was isolated from traditional sour milk in Sinkiang of China with desirable probiotic properties. Here we report the complete genome sequence of this organism and its genetic basis for adhesion, exopolysaccharides (EPS) production, acid and bile tolerance, bacteriocin production and immune system against bacteriophage.