Exudative epidermitis of piglets caused by non-toxigenic Staphylococcus sciuri

Infections with strains of Staphylococcus sciuri are a potential threat to animal and public health, and a cause for considerable concern. We isolated and identified S. sciuri as a pathogen from an acute outbreak of exudative epidermitis in piglets for further genetic identification using experimental infections. The results of this study showed that S. sciuri strain NJ1306 reproduced exudative epidermitis in experimentally infected 5-day-old piglets. The isolated bacteria also caused sudden death in BALB/c mice following intraperitoneal injection with 5×10⁸ CFU of the isolate. The data indicated that strain NJ1306 of S. sciuri was pathogenic to piglets and mice, and the study provided the first known report of clinical lung lesions and endocarditis in piglets due to S. sciuri.

Size-dependent assembly of ligated gold nanocrystals in two dimensions

Brownian dynamics (BD) simulation based on a coarse-grained model is performed to study the assembly of dodecanethiol-ligated Au nanocrystals (NCs) at a toluene-air interface. With increasing diameter from 3 nm to 9 nm, the NCs are found to form three different phases-a dispersed phase without aggregation, a mixture of dispersed NCs and rounded clusters, and a compactly packed solid phase of the fractal structure. Such size dependence of the assembled phase is attributed to the variation in the well depth [Formula: see text] of the interaction potential between NCs, and the value of [Formula: see text] for 6 nm NCs turns out to be most suitable to form monolayers with hexagonal packing. The result is of universal importance for assembling complete monolayers, because the valley of the interaction potential can be well tailored by properly choosing the NC size, ligand length and solvent.

Clinical implications of studies with MnDPDP in animal models of hepatic abnormalities

Mangafodipir trisodium (manganese dipyridoxal diphosphate or MnDPDP) has been introduced as a hepatobiliary MR contrast agent (Teslascan). Its potential to assist in the characterisation of focal liver lesions, the diagnosis of local and global obstructive cholestasis and the evaluation of hepatic function in diffuse liver diseases has been explored in multiple pre-clinical experiments with appropriate animal models. The prompt negative contrast enhancement and delayed peritumoural rim-enhancement seen after i.v. injection of MnDPDP are 2 typical features of primary and secondary liver tumours with high malignancy, while the persistent positive enhancement is a sign of liver tumours of well preserved hepatocytic nature. Liver with local and total biliary obstruction can be visualized in MnDPDP-enhanced MR images as a region with prolonged signal enhancement. This agent could also be used to non-invasively evaluate diffuse liver diseases of different causes.

In the present paper, we review the experimental data in the literature, provide some unpublished results and discuss the potential impact on the clinical use of MnDPDP in the liver. We conclude that MnDPDP is a promising MR liver contrast agent for the detection and characterisation of focal and diffuse liver diseases.

Comparison of manganese biodistribution and MR contrast enhancement in rats after intravenous injection of MnDPDP and MnCl2

Purpose: To compare the time course of the MR enhancing properties and biodistri-bution of manganese (Mn) in rats given i.v. Mn dipyridoxyl diphosphate (MnDPDP) or Mn chloride (MnCl2).

Material and Methods: Twenty-four adult rats were injected i.v. with 5 μmol/kg MnDPDP or MnCl2, or with 0.5 ml/kg saline. High resolution T1-weighted MR imaging was performed during early (10 min), mid (2 h) and late (24 h) phases after injection. Mn concentrations in major organs were measured by using an ICP-AES technique, and correlated with MR findings.

Results: Variable degrees of signal enhancement of major organs observed in MR images corresponded with the amount of Mn uptake after injection of MnDPDP or MnCl2. A prominently lower cardiac, pancreatic and hepatic uptake of Mn was seen at 10 min in rats injected with MnDPDP compared with those given MnCl2 and this was reflected in a difference in signal intensity (SI) in the MR images. At 2 h, the Mn content and SI in the major organs were similar with both MnDPDP and MnCl2. An overall Mn clearance was achieved at 24 h without any important organ retention, with kidney excretion of Mn seen only with MnDPDP.

Conclusion: With both MnDPDP and MnCl2, the Mn uptake correlates with the SI enhancement in tissues. The reduced initial cardiac uptake of Mn after MnDPDP treatment compared to MnCl2 may account for the favourable cardiovascular safety of the contrast agent. These data contribute to an understanding of SI enhancement by MnDPDP, and are consistent with other studies showing that at a dose of 5 μmol/kg, MnDPDP can be safely used as a potent MR organ-specific contrast agent.

Optimization of selective breeding through analysis of morphological traits in Chinese sea bass (Lateolabrax maculatus)

Determining correlations between certain traits of economic importance constitutes an essential component of selective activities. In this study, our aim was to provide effective indicators for breeding programs of Lateolabrax maculatus, an important aquaculture species in China. We analyzed correlations between 20 morphometric traits and body weight, using correlation and path analyses. The results indicated that the correlations among all 21 traits were highly significant, with the highest correlation coefficient identified between total length and body weight. The path analysis indicated that total length (X₁), body width (X₅), distance from first dorsal fin origin to anal fin origin (X₁₀), snout length (X₁₆), eye diameter (X₁₇), eye cross (X₁₈), and slanting distance from snout tip to first dorsal fin origin (X₁₉) significantly affected body weight (Y) directly. The following multiple-regression equation was obtained using stepwise multiple-regression analysis: Y = -472.108 + 1.065X₁ + 7.728X₅ + 1.973X₁₀ - 7.024X₁₆ - 4.400X₁₇ - 3.338X₁₈ + 2.138X₁₉, with an adjusted multiple-correlation coefficient of 0.947. Body width had the largest determinant coefficient, as well as the highest positive direct correlation with body weight. At the same time, high indirect effects with six other morphometric traits on L. maculatus body weight, through body width, were identified. Hence, body width could be a key factor that efficiently indicates significant effects on body weight in L. maculatus.

Elastic properties of gold supracrystals: Effects of nanocrystal size, ligand length, and nanocrystallinity

Atomistic molecular dynamics simulations are performed to study the elastic properties of alkylthiol-functionalized gold supracrystals. The predicted Young's and shear moduli are around 1 GPa and 100 MPa, respectively. We show that, with increasing NC size, the Young's modulus decreases while the shear modulus essentially remains invariant; with increasing ligand length, the Young's modulus increases but the shear modulus decreases. Moreover, significant increase in the Young's modulus is seen when the polycrystalline NCs are replaced by single-crystal ones of the same size. All these are in reasonable agreement with available experiments. We attribute the mechanisms to the interaction between capping ligands as well as its variations caused by the change in ligand length and NC geometry. The results may deepen our understanding of elastic properties of the supracrystals and their influential factors.

Molecular dynamics simulation of interparticle spacing and many-body effect in gold supracrystals

Interparticle spacing in supracrystals is a crucial parameter for photoelectric applications as it dominates the transport rates between neighboring nanoparticles (NPs). Based on large-scale molecular dynamics simulations, we calculate interparticle spacing in alkylthiol-stabilized gold supracrystals as a function of the NP size, ligand length and external pressure. The repulsive many-body interactions in the supracrystals are also quantified by comparing the interparticle spacing with that between two individual NPs at equilibrium. Our results are consistent with available experiments, and are expected to help precise control of interparticle spacing in supracrystal devices.

Interface failure modes explain non-monotonic size-dependent mechanical properties in bioinspired nanolaminates

Bioinspired discontinuous nanolaminate design becomes an efficient way to mitigate the strength-ductility tradeoff in brittle materials via arresting the crack at the interface followed by controllable interface failure. The analytical solution and numerical simulation based on the nonlinear shear-lag model indicates that propagation of the interface failure can be unstable or stable when the interfacial shear stress between laminae is uniform or highly localized, respectively. A dimensionless key parameter defined by the ratio of two characteristic lengths governs the transition between the two interface-failure modes, which can explain the non-monotonic size-dependent mechanical properties observed in various laminate composites.

Artificial pneumothorax for pain relief during microwave ablation of subpleural lung tumors

BACKGROUND

When microwave ablation (MWA) is used for subpleural lesions, severe pain was the common side effect under the local anesthesia conditions during the procedure and postprocedure. To study the pain relief effect of artificial pneumothorax in the treatment of subpleural lung tumors with MWA.

MATERIALS AND METHODS

From February 2012 to October 2014, 37 patients with 40 subpleural lung tumors underwent MWA, including 17 patients of 19 sessions given artificial pneumothorax prior to MWA (group-I), and 20 patients of 21 sessions without artificial pneumothorax (group-II). Patient's pain assessment scores (10-point visual analog scale [VAS]) at during-procedure, 6, 12, 24, and 48 h after the MWA procedure and mean 24 h morphine dose were compared between the two groups. Complications of the artificial pneumothorax were also summarized.

RESULTS

Pain VAS were 0.53, 0.65, 1.00, 0.24, and 0.18 at during-procedure, 6, 12, 24, and 48 h for group-I and 5.53, 2.32, 2.82, 1.21, and 0.21 for group-II, respectively. Pain VAS in group I was significantly decreased at during-procedure, 6, 12, and 24 h after the MWA (P < 0.001). No statistical pain VAS difference was observed at 48 h after the MWA between the two groups (P > 0.05). The mean 24 h morphine dose was 5.00 mg in group-I and 12.63 mg in group-II (P = 0.000). "Artificial pneumothorax" related complications occurred in two patients from group-I, including one pleural effusion and one minor hemoptysis. No patient in group-I and group-II died during the procedure or in 30 days after MWA.

CONCLUSION

Artificial pneumothorax is a safe and effective method for pain relief during MWA of subpleural lung tumors.

Molecular identification of the genus Thryssa based on DNA barcoding

DNA barcoding is an effective method for identifying species by analyzing one or a few short standardized DNA sequences. In this study, we examined the utility of mitochondrial cytochrome oxidase subunit I (COI) sequences as a DNA barcode for the identification of six species belonging to the genus Thryssa: T. dussumieri, T. hamiltonii, T. kammalensis, T. mystax, T. setirostris, and T. vitrirostris. We obtained an intraspecific distance of 0.000 for T. vitrirostris and T. hamiltonii, 0.006 for T. mystax, 0.002 for T. dussumieri, and 0.005 for T. kammalensis. The average intraspecific distance was 0.002, while the average interspecific distance was 0.137. Thus, the interspecific genetic distance was approximately 67-fold larger than the intraspecific genetic distance; the average genetic distance among species was greater than the minimum of 0.020 between species suggested elsewhere. The genetic distance between T. vitrirostris and T. mystax was 0.003. A maximum-likelihood phylogenetic tree constructed using best-fitting tree topology showed distinct clusters corresponding to the species (except for T. vitrirostris and T. mystax). The closest relationship was found between T. vitrirostris and T. mystax. These two species clustered together in the phylogenetic tree. This conclusion contradicts the evolutionary relationship based on morphological classification.

2-(3',5'-Dimethoxybenzylidene) cyclopentanone, a novel synthetic small-molecule compound, provides neuroprotective effects against ischemic stroke

2-(3',5'-Dimethoxybenzylidene) cyclopentanone (DMBC) is a novel small-molecule compound synthesized by our group. Here, we found that in rat models of permanent middle cerebral artery occlusion (pMCAO), intraperitoneal injection (ip) of DMBC at 1h after ischemia reduced infarct volume, improved neurological deficits and increased the protein levels of microtubule-associated protein 2 (MAP 2) and glial fibrillary acid protein (GFAP) in the ischemic cortex. Post-treatment of DMBC still produced neuroprotective effects even when administered at 6h after ischemia. In the oxygen-glucose deprivation (OGD)-induced astrocytes or HT22 cell injury, DMBC treatment decreased the OGD-induced lactate dehydrogenase (LDH) leakage and increased the GFAP levels in astrocytes. In addition, Annexin-V-Fluos staining analysis revealed that DMBC treatment attenuated both OGD-induced apoptosis and necrosis in astrocytes. Western blotting analysis showed DMBC treatment inhibited the ischemia or OGD-induced increases in active cathepsin B in the ischemic cortex or in astrocytes or HT22 cells. Immunofluorescence analysis demonstrated that DMBC treatment blocked the ischemia or OGD-induced release of cathepsin B from the lysosomes into the cytoplasm in the ischemic cortex or in astrocytes or HT22 cells. Taken together, our results indicate that DMBC can offer neuroprotective effects against cerebral ischemia with an extended therapeutic window and its mechanism might be associated with inhibition of the cathepsin B activation.

Dielectric constant and low-frequency infrared spectra for liquid water and ice Ih within the E3B model

Two intrinsic difficulties in modeling condensed-phase water with conventional rigid non-polarizable water models are: reproducing the static dielectric constants for liquid water and ice Ih, and generating the peak at about 200 cm(-1) in the low-frequency infrared spectrum for liquid water. The primary physical reason for these failures is believed to be the missing polarization effect in these models, and consequently various sophisticated polarizable water models have been developed. However, in this work we pursue a different strategy and propose a simple empirical scheme to include the polarization effect only on the dipole surface (without modifying a model's intermolecular interaction potential). We implement this strategy for our explicit three-body (E3B) model. Our calculated static dielectric constants and low-frequency infrared spectra are in good agreement with experiment for both liquid water and ice Ih over wide temperature ranges, albeit with one fitting parameter for each phase. The success of our modeling also suggests that thermal fluctuations about local minima and the energy differences between different proton-disordered configurations play minor roles in the static dielectric constant of ice Ih. Our analysis shows that the polarization effect is important in resolving the two difficulties mentioned above and sheds some light on the origin of several features in the low-frequency infrared spectra for liquid water and ice Ih.

Combretastatin A4-phosphate and its potential in veterinary oncology: a review

For many years, research on anticancer therapy has focussed almost exclusively on targeting cancer cells directly, to selectively kill them or restrict their growth. But limited advances in this strategy have led researchers to shift their attention to other potential targets. Active research is now on-going on targeting tumour stroma. Vascular disrupting agents (VDAs) appear a promising class of anticancer drugs that are currently under investigation as a sole or combined therapy in human cancer patients. This article will briefly touch on the history and biology of combretastatin A4-phosphate (CA4P) as a typical example of VDAs and will concentrate on the side effects that can be expected when used in veterinary patients. Particularly, the pathogenesis of these side effects and how they may be prevented and/or treated will be discussed. The purpose of this article is to illustrate the potentials of CA4P as anticancer therapy in veterinary oncology patients.

Molecular epidemiology of carbapenemase-producing Escherichia coli and the prevalence of ST131 subclone H30 in Shanghai, China

The molecular characteristics and epidemiology of carbapenemase-producing Escherichia coli (CPEC) isolates from Shanghai, China, were investigated using 21 imipenem-resistant E. coli isolates obtained from a Shanghai teaching hospital from 2011 to 2014. The presence of bla KPC, bla IMP, bla VIM, bla OXA-48, and bla NDM was assessed by polymerase chain reaction (PCR) amplification and sequencing. CPEC isolates were characterized by the Etest®, multilocus sequence typing (MLST), and pulse-field gel electrophoresis (PFGE). Plasmids carrying resistance genes were analyzed by conjugation experiments, replicon typing, plasmid MLST (pMLST), S1 nuclease PFGE (S1-PFGE), and Southern hybridization. The genetic environment of the resistance genes was determined by PCR and sequencing. Among the 21 E. coli isolates, 16 produced carbapenemases; of these, ten isolates transferred carbapenemase-encoding plasmids to recipient bacteria. Nine of the 16 isolates were clonally related, and their PFGE patterns were designated type A. ST131 was the predominant sequence type (11 isolates, 68.8 %); the H30 subclone comprised 81.8 % of the ST131 strains. In all three isolates, bla IMP-4 was located on 50-kb IncN plasmids. All but two bla KPC-2 genes were carried on IncF plasmids of various sizes. Hence, both clone-spread and horizontal transfer mediated the dissemination of carbapenemase-producing genes in the Shanghai isolates.

Novel l-lactic acid biosensors based on conducting polypyrrole-block copolymer nanoparticles

Novel polypyrrole-Pluronic F127 nanoparticles with conducting and biocompatibility properties were used to construct an l-lactic acid biosensor. This method proposes great potential for the detection and evaluation of meat quality.

A coarse-grained simulation for tensile behavior of 2D Au nanocrystal superlattices

We performed a coarse-grained. molecular dynamics (MD) simulation to study the unidirectional tension of 2D superlattices of alkythiol-ligated Au nanocrystals (NCs). Consistent with available experiments, the predicted Young's modulus is in the range of 6-15 GPa, exhibiting a trend of decreasing with the increasing NCs' size and decreasing ligand length. Our simulation shows that the deformation of the superlattice experiences elastic and nonelastic stages before defect nucleation at the NC level. The larger tensile strain gives rise to slips along the most densely packed lines, making them equal to [Formula: see text] with the tensile direction before deformation, which further triggers the occurrence of cavities and cracks and finally leads to the fracture of the specimen. These results provide a clear picture for the tensile behavior of 2D superlattices from deformation to rupture.

Molecular characterization of the extended-spectrum beta-lactamase (ESBL)-producing Shigella spp. in Shanghai

Shigellosis is a public health concern in China. We tested 216 Shigella isolates collected in Shanghai in 2007 for the production of extended-spectrum beta-lactamases (ESBLs). ESBL-producing isolates were characterized using polymerase chain reaction (PCR)-based genotyping, conjugation, pulsed-field gel electrophoresis (PFGE), and DNA sequence analysis of regions adjacent to bla genes. Plasmids containing genes encoding ESBLs were analyzed using plasmid replicon typing. ESBLs were produced by 18.1 % (39/216) of Shigella isolates, and all 39 ESBL-producing strains harbored bla CTX-M genes. CTX-M-14 was the most frequent variant (69.2 %, 27/39), followed by CTX-M-15 (15.4 %, 6/39). All bla CTX-M genes were transferable by conjugation, and the insertion sequence ISEcp1 was detected upstream of all bla CTX-M genes. The CTX-M-producing Shigella isolates showed high clonal diversity. IncI1, IncFII, IncN, and IncB/O replicons were respectively detected in 23 (58.9 %), 9 (23.1 %), 1 (2.6 %), and 1 (2.6 %) of the 39 transconjugants carrying bla CTX-M. The bla CTX-M-14 genes were most frequently carried by IncI1 (n = 13, 48.1 %) or IncFII (n = 9, 33.3 %) plasmids, and the bla CTX-M-15 genes were closely associated with IncI1 (n = 5, 83.3 %). Our findings demonstrate the high prevalence of ESBL-producing Shigella in Shanghai, the importance of plasmids and ISEcp1 as carriers of bla CTX-M genes, and the close association between certain bla CTX-M genes with a specific plasmid.

Kisspeptin-10 enhanced egg production in quails associated with the increase of triglyceride synthesis in liver

Our previous results showed that kisspeptin-10 (Kp-10) injections via intraperitoneal (i.p.) once daily for three weeks notably promoted the egg laying rate in quails. In order to investigate the mechanism behind the effects of Kp-10 on enhancing the egg laying rate in birds, this study focused on the alternations of lipids synthesis in liver after Kp-10 injections. 75 female quails (22 d of age) were allocated to three groups randomly, and subjected to 0 (control, Con), 10 nmol (low dosage, L) and 100 nmol (high dosage, H) Kp-10 injections via i.p. once daily for three weeks, respectively. At d 52, quails were sacrificed and sampled for further analyses. Serum E2 concentration was increased by Kp-10 injections, and reached statistical significance in H group. Serum triglyceride (TG) concentrations were increased by 46.7% in L group and 36.8% in H group, respectively, but did not reach statistical significance, and TG contents in liver were significantly elevated by Kp-10 injections in a dose-dependent manner. Serum total cholesterol (Tch) concentrations significantly decreased in H group, while in H group the hepatic Tch content was markedly increased. The level of non-esterified fatty acid (NEFA), apolipoprotein A1 and B (apoA1 and apoB) were not altered by Kp-10 injections. The genes expression of sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthetase (FAS), apolipoprotein VLDL-II (apoVLDL-II), cholesterol 7α-hydroxylase (CYP7A1) and vitellogenin II (VTG-II) were significantly up-regulated by high but not low dosage of Kp-10 injection compared to the control group. However, the expression of SREBP-2, acetyl-CoA carboxylase (ACCα), malic enzyme (ME), stearoyl-CoA (Δ9) desaturase 1 (SCD1), apolipoprotein A1 (apoA1), fatty acid binding protein 2 (FABP2), 3-hydroxyl-3-methyl glutaryl-coenzyme A reductases (HMGCR), estrogen receptor α, β (ERα and β) mRNA were not affected by Kp-10 treatment. In line with hepatic mRNA abundance, hepatic SREBP1 protein content was significantly higher in H group. Although the mRNA expression was not altered, the content of ERα protein in liver was also significantly increased in H group. However, SREBP-2 protein content in liver was not changed by Kp-10 treatment. In conclusion, exogenous Kp-10 consecutive injections during juvenile stage significantly advanced the tempo of egg laying in quails, which was associated with the significant elevation in hepatic lipids synthesis and transport.

Effects of kisspeptin-10 on lipid metabolism in cultured chicken hepatocytes

Our previous studies showed that kisspeptin-10 (Kp-10) injected in vivo can markedly increase lipid anabolism in liver of quails. In order to investigate the direct effect of Kp-10 on lipid metabolism of hepatocytes in birds, cells were separated from embryos livers and cultured in vitro with 0, 100 and 1,000 nM Kp-10, respectively. The results showed that after 24 h treatment, cells viability was not affected by 100 nM Kp-10, but showed a mild decrease with 1,000 nM Kp-10 compared to the control cells. Based on the results of the cell viability, 100 nM dosage of Kp-10 was selected for the further study and analysis. Compared with control cells, total cholesterol (Tch) contents in 100 nM treated cells were increased by 51.23%, but did not reach statistical significance, while the level of triglyceride (TG), high density of lipoprotein-cholesterol (HDL-C) and low density of lipoprotein-cholesterol (LDL-C) were significantly increased. Real-time PCR results showed that ApoVLDL-II mRNA expression had a tendency to increase, genes including sterol regulatory element-binding protein-1 (SREBP-1), acetyl coenzyme A carboxylase α (ACCα), carnitine palmitoyltransferase 1 (CPT1), 3-hydroxyl-3-methylglutaryl-coenzyme A reductases (HMGCR) and stearyl coenzyme A dehydrogenase-1 (SCD1) mRNA in hepatocytes were significantly down-regulated by 100 nM Kp-10. However, contrary to its gene expression, SREBP-1 protein expression was significantly up-regulated by 100 nM Kp-10. Some of the significant correlations in mRNA expression were found between genes encoding hepatic factors or enzymes involved in lipid metabolism in liver of birds. These results indicate that Kp-10 stimulates lipid synthesis directly in primary cultured hepatocytes of chickens.

Monoclonal antibodies against Nsp2 protein of the highly pathogenic porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome (PRRS) continues to be a serious threat, causing an economically significant impact on the swine industry worldwide. In this study, non-structural protein Nsp2 of porcine reproductive and respiratory syndrome virus (PRRSV) was expressed in Escherichia coli and purified by dialysis. An important monoclonal antibody (MAb 2H6) against Nsp2 protein was generated by fusing mouse myeloma cell line SP2/0 with spleen lymphocytes from Nsp2 protein immunized mice. Then activity of the MAb was characterized by enzyme-linked immunosorbent assay (ELISA), Western blot analysis, and indirect immunofluorescence assays. The results demonstrated that the MAb has a positive reaction to HP-PRRSV in IFA at 1:100 dilution and in Western blot analysis at 1:500 dilution, and no reaction with classic PRRSV. These indicated that this MAb against Nsp2 protein of PRRSV might be a good candidate for a specific diagnostic method and functional exploration of the Nsp2 protein.

Differential expression of hypothalamic fear- and stress-related genes in broiler chickens showing short or long tonic immobility

The serotonin system and the hypothalamic-pituitary-adrenal axis play important roles in modulating fear and stress-coping characteristics. Tonic immobility (TI) is a fear-related phenotype, and previously we have shown that broiler chickens showing short TI (STI) duration experience better growth performance and higher adaptability to stress. Here, we sought to further elucidate the central mechanisms underlying the phenotypic differences between chickens showing STI and long TI duration, by comparing the hypothalamic expression of genes in the serotonergic system and the hypothalamic-pituitary-adrenal axis under basal and corticosterone-exposed situations. The STI broilers had significantly lower (P < 0.01) hypothalamic expression of serotonin reuptake transporter and serotonin receptor 1A. Moreover, 11β-hydroxysteroid dehydrogenase type 2 was expressed significantly lower in STI chickens at the level of both mRNA (P < 0.01) and protein (P < 0.05). Hypothalamic expression of glucocorticoid receptor (GR) mRNA tended to be higher (P < 0.059) in long TI chickens, but the protein content was approximately 2 times higher (P < 0.01) in STI chickens. The uncoupled expression of GR mRNA and protein was associated with significantly lower (P < 0.05) expression of gga-miR-181a, gga-miR-211, and gga-miR-22, which are predicted to target GR, in STI chickens. Corticosterone administration reduced the mRNA expression of postsynaptic serotonin receptors, 5-hydroxytryptamine receptor 1B (P = 0.059) and 5-hydroxytryptamine receptor 7 (P < 0.05), yet significantly increased the protein content of 11β-hydroxysteroid dehydrogenase type 2 (P < 0.05). These results suggest that broilers of different TI phenotypes have a distinct pattern of hypothalamic expression of fear- and stress-related genes.

Contribution of eukaryotic-type serine/threonine kinase to stress response and virulence of Streptococcus suis

Streptococcus suis serotype 2 (SS2) is an important swine and human pathogen responsible for septicemia and meningitis. The bacterial homologues of eukaryotic-type serine/threonine kinases (ESTKs) have been reported to play critical roles in various cellular processes. To investigate the role of STK in SS2, an isogenic stk mutant strain (Δstk) and a complemented strain (CΔstk) were constructed. The Δstk showed a significant decrease in adherence to HEp-2 cells, compared with the wild-type strain, and a reduced survival ratio in whole blood. In addition, the Δstk exhibited a notable reduced tolerance of environmental stresses including high temperature, acidic pH, oxidative stress, and high osmolarity. More importantly, the Δstk was attenuated in both the CD1 mouse and piglet models of infection. The results of quantitative reverse transcription-PCR (qRT-PCR) analysis indicated that the expressions of a few genes involving in adherence, stress response and virulence were clearly decreased in the Δstk mutant strain. Our data suggest that SsSTK is required for virulence and stress response in SS2.