Immunization with the lipoprotein FtsB stimulates protective immunity against Streptococcus pyogenes infection in mice.

Streptococcus pyogenes is one of the main pathogenic bacteria that causes disease in humans. It is reported that over 18 million cases of S. pyogenes disease occurred in the world, and more than 500,000 deaths occur annually worldwide. An effective vaccine is widely regarded as the most reliable way to control and prevent streptococcal infections. However, there is currently no approved vaccine for S. pyogenes. In this study, we evaluated the potential of lipoprotein FtsB as a new vaccine candidate to prevent S. pyogenes infection. Mice vaccinated with purified FtsB protein elicited high titers of IgG, IgG1 and IgG2a antibodies in mouse serum. Vaccinated with FtsB can reduce bacterial systemic dissemination in the blood, heart, and spleen and reduce organ damage in the mouse bacteremia model. In addition, active immunization with FtsB protected against streptococcal abscess formation. Furthermore, immunization with FtsB was efficient in inducing a mixed cellular immune response and promoting the maturation of dendritic cells in mice. The lipoprotein HtsA was served as a positive control because it has been reported to protect mice from S. pyogenes infection in both active and passive immunization. These findings demonstrated that lipoprotein FtsB may serve as a candidate vaccine for the prevention of S. pyogenes infection.

Chlorogenic acid exerts antibacterial effects by affecting lipid metabolism and scavenging ROS in Streptococcus pyogenes.

Chlorogenic acid (CGA), one of the most abundant polyphenols in the human diet, exhibits many biological properties, including antibacterial properties. Numerous studies have investigated the antibacterial effects of CGA, however, the molecular mechanisms governing its effects against Streptococcus pyogenes have not been fully elucidated. Streptococcus pyogenes is a Gram-positive pathogen that causes a wide range of human infections and postinfectious immune-mediated disorders. In this study, we used an isobaric tagging for relative and absolute quantitation (iTRAQ)-based proteomic technique to investigate the underlying mode of action of CGA against S. pyogenes. KEGG and GO analyses indicated that CGA affected the expression of protein alterations involved in multiple pathways, downregulating the expression of ribosomal proteins, and upregulating the expression of proteins associated with fatty acid metabolism, pyruvate metabolism, and propanoate metabolism, while activating the expression of oxidation-reduction-related proteins. Moreover, further cell-based experiments verified that CGA scavenges intracellular ROS in S. pyogenes. These results suggest that CGA may exert its antibacterial action through several actions, such as downregulating ribosomal subunits, affecting lipid metabolism, and scavenging intracellular ROS. The results of this study may help to elucidate the molecular mechanisms by which CGA combats pathogens.

The Role and Regulatory Network of the CiaRH Two-Component System in Streptococcal Species.

Pathogenic streptococcal species are responsible for a broad spectrum of human diseases ranging from non-invasive and localized infections to more aggressive and life-threatening diseases, which cause great economic losses worldwide. Streptococci possess a dozen two-component systems (TCSs) that play important roles in the response to different environmental changes and adjust the expression of multiple genes to successfully colonize and infect host cells. In this review, we discuss the progress in the study of a conserved TCS named CiaRH in pathogenic or opportunistic streptococci including Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus mutans, Streptococcus gordonii, Streptococcus sanguinis, and Streptococcus suis, focusing on the function and regulatory networks of CiaRH, which will provide a promising strategy for the exploration of novel antistreptococcal therapies. This review highlights the important role of CiaRH and provides an important basis for the development of antistreptococcal drugs and vaccines.

miR-23b Attenuates LPS-Induced Inflammatory Responses in Acute Lung Injury via Inhibition of HDAC2.

Inflammatory responses play significant role in infectious etiology-induced acute lung injury (ALI). Histone deacetylase 2 is found to be essential and stimulated in lipopolysaccharide (LPS)-induced ALI by regulating proinflammatory cytokines. miR-23b has been demonstrated to be downregulated in LPS-induced inflammatory injury. In this study, we aimed to explore the interaction between miR-23b and HDAC2 and their function in LPS-induced ALI. LPS treatment was induced on murine alveolar macrophage cell line MH-S. Level of miR-23b and HDAC2 were determined by real-time PCR or Western blot. Proinflammatory cytokines expression and secretion were detected by real-time PCR and ELISA assay. The levels of miR-23b and HDAC2 were manipulated by transient transfection of miRNA mimics, shRNA or overexpression vector. The interaction between miR-23b and HDAC2 were tested by Luciferase reporter assay. LPS treatment inhibited miR-23b expression, while increased HDAC2 level in MH-S cells. Proinflammatory cytokines were stimulated by LPS treatment. Knockdown of HDAC2 or overexpression of miR-23b significantly repressed the expression of proinflammatory cytokines induced by LPS. miR-23b could suppress HDAC2 expression by directly targeting to its mRNA. LPS treatment stimulated the inflammatory responses in macrophages through inhibition of miR-23b, enhanced HDAC2 expression and inducing the expression of its downstream targets TNF-α, IL-6, and IL-1ß. Overexpression of miR-23b was sufficient to suppress inflammatory responses by targeting HDAC2, making it a promising therapeutic target to ALI treatment.

Linear-shaped Ln and Ln clusters constructed by a polydentate Schiff base ligand and a ß-diketone co-ligand: structures, fluorescence properties, magnetic refrigeration and single-molecule magnet behavior.

Herein, ten new linear-shaped LnIII4 and LnIII6 clusters, with the formula [Ln4(acac)6L2(CH3O)2(CH3OH)4]·xCH3OH (Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), and Tm (8), Hacac = acetylacetone), [Ln6(acac)4L4(CH3O)6]·xCH3OH (Er (7) and Yb (9)), and [Lu4(acac)6L2(OH)2]·2CH2Cl2 (10), based on a polydentate Schiff base ligand, H2L, and a ß-diketone co-ligand were successfully synthesized and structurally characterized. Single crystal X-ray diffraction measurements reveal that the structures of the clusters 1-6, 8 and 10 are very similar and their central Ln(iii) ions are linearly arranged Ln4; however, the clusters 7 and 9 possess a rare linearly arranged Ln6. The investigations on the solid-state fluorescence properties show that the clusters 2, 3, 5 and 6 display the characteristic lanthanum luminescence at room temperature. Magnetic studies reveal that weak antiferromagnetic interactions exist between adjacent Gd(iii) ions in cluster 4. More importantly, the cluster 4 exhibits significant MCE with the maximum -ΔSm value of 27.96 J kg-1 K-1 at 2.0 K and 7.0 T, whereas the cluster 6 displays a slow magnetic relaxation behavior under a zero dc field with the effective energy barrier ΔE/kB = 8.64 K and τ0 = 6.98 × 10-6 s.

[Influence of nitrogen and phosphorus addition on the aboveground biomass in Inner Mongo- lia temperate steppe, China].

The plants in arid environment are constrained not only by water availability, but also by soil nutrient conditions. In order to clarify to what extent nutrient addition would facilitate the growth of plants in semi-arid region, we conducted a nitrogen (N) and phosphorus (P) addition experiment in Inner Mongolia temperate grassland in 2012 and 2013. In our experiment, N was added at 10 and 40 g N · m(-2) · a(-1) alone or in combination with P addition (10 g P · m(-2) · a(-1)). N addition significantly improved plant aboveground biomass (AGB) during the two study years. AGB in the treatments of 10 and 40 g · m2 · a(-1) was enhanced by 50.8% and 65.9% in 2012, and 71.6% and 93.3% in 2013, respectively. However, no significant difference in AGB enhancement was found between two N addition treatments. Compared with N addition treatments at the rates of 10 and 40 g · m(-2) · a(-1), N plus P addition improved AGB by 98.4% and 186.8% in 2012, and 111.7% and 141.4% in 2013, respectively. N addition generally increased all the three main functional types (i.e., Gramineae, Asteraceae and others) , and the three functional types contributed nearly equally to the increase of the community AGB. In comparison, Asteraceae contributed largest to the increments of AGB under the N plus P addition treatments. Our results also indicated that N and P addition remarkably increased the ground coverage, resulting in improved surface soil moisture condition, which might be one important reason that N and P addition could facilitate plant growth in arid environment.

[Biological characters of rice on P-deficient soils with different pH value].

With pot culture, this paper studied the biological characters of four low-P tolerant rice genotypes 99011, 580, 508 and 99112 and two low-P sensitive rice genotypes 99012 and 99056 on three P-deficient soils with different pH. The results indicated that on test soils, 580, 508 and 99112 had similar low-P tolerant ability. 99011 had poor low-P tolerant ability on alkaline soil, with its relative grain yield being 11.9% and 10.4% less than that on acid and neutral soil, respectively. 99012 showed a relatively stronger low-P tolerant ability on alkaline soil, and its relative grain yield was 19.6% higher than that on acid soil and 22.2% higher than that on neutral soil. 99056 showed a stronger low-P tolerant ability on acid soil, and its relative grain yield was 25.0% and 19.6% higher than that on alkaline and neutral soil, respectively. The effects of soil P level and soil type on rice grain yield mainly manifestied on the number of available spike. The P concentration and its relative value in flag leaves of 99011, 580, 508 and 99112 were significantly higher than those of 99012 and 99056, which might be another factor resulting in the stronger low-P tolerant ability of 99011, 580, 508 and 99112 than 99012 and 99056.

[Isolation of maize genes related to aluminum tolerance].

To investigate gene expression profile in response to aluminum stress and to cloning the key genes related to aluminum tolerance, are crucial to genetic improvement of plant aluminum tolerance. In this study, suppression subtractive hybridization method was adopted to construct SSH-cDNA libraries at seedling stage of two maize inbred lines (Fig. 1), of which Mo17 is sensitive to aluminum toxicity and TL94B is tolerant. As a result, a forward SSH-cDNA library including 762 clones and a reverse SSH-cDNA library including 382 clones were constructed for Mo17. In the same way, a forward SSH-cDNA library including 760 clones and a reverse SSH-cDNA library including 380 clones were constructed for TL94B. Identification of these SSH-cDNA libraries shows that the length of inserted fragments ranges from 250 bp to 1.0 kb (Fig. 2), of which nearly 18% are positive clones. Through differential hybridization screening (Fig. 3), 124 and 47 positive clones were screened from forward and reverse SSH-cDNA libraries of Mo17 respectively; 103 and 64 positive clones from forward and reverse SSH-cDNA libraries of TL94B respectively. Total 338 positive clones from four SSH-cDNA libraries were sequenced, and all of the sequences of inserted fragments were analyzed using bioinformatical methods. A total of 232 kinds of EST sequences were obtained. Among these ESTs, 70.2% had significant homology with known genes, and the remaining 29.8% were function-unknown including 21 kinds of newly found ESTs (Table 1). An aluminum tolerant gene, GDP dissociation inhibitor gene, was detected its expression character by Northern hybridization (Fig. 4). These results indicate that the responses of maize to aluminum stress involve the interactions among different signal/metabolism pathways, such as signal transduction of stress-related factors, transcription and regulation of responsive genes, synthesis and transport of substances, changes in cell structures and functions.

[The genetic analysis of Al-tolerance in maize].

The heredity of Al-tolerance was studied in different Al-tolerance of two inbred lines of maize and their F1, F2, B1 and B2 generations by the means of nutritional cultivation. The results indicated that the relative biomass (Al/CK) of root had high hereditary variance, the broad-sense heredity reached 78.6 %, but narrow-sense heredity only had 15.4 %. Its hereditary pattern mainly was dominant effects. On contrast, the relative biomass of shoot had high narrow-sense heredity (43.1%), it means that the hereditary pattern of relative biomass of shoot mainly was additive effects. On the hereditary ground of 0.1 mmol/L Al(3+), the broad-sense heredity of total absorbing surface to volume ratio and active absorbing surface to volume ratio were 17.9 % and 36.4 %, and narrow-sense heredity of them were 10.0 % and 18.4 %. It means that the characters of root activity were obviously affected by environment.