An interval-based regret-analysis method for identifying long-term municipal solid waste management policy under uncertainty

In this study, an interval-based regret-analysis (IBRA) model is developed for supporting long-term planning of municipal solid waste (MSW) management activities in the City of Changchun, the capital of Jilin Province, China. The developed IBRA model incorporates approaches of interval-parameter programming (IPP) and minimax-regret (MMR) analysis within an integer programming framework, such that uncertainties expressed as both interval values and random variables can be reflected. The IBRA can account for economic consequences under all possible scenarios associated with different system costs and risk levels without making assumptions on probabilistic distributions for random variables. A regret matrix with interval elements is generated based on a matrix of interval system costs, such that desired decision alternatives can be identified according to the interval minimax regret (IMMR) criterion. The results indicate that reasonable solutions have been generated. They can help decision makers identify the desired alternatives regarding long-term MSW management with a compromise between minimized system cost and minimized system-failure risk.

Sequence analyses of the representative Chinese-prevalent strain of avian nephritis virus in healthy chicken flocks

Avian nephritis virus (ANV), which belongs to the Astroviridae family, has been associated with acute nephritis in chickens. Cases of ANV infection have been recorded in Japan and in several European countries. However, related studies have never been performed in China. Thus, this study isolated ANV in Chinese chicken flocks. ANV RNA was detected by reverse transcription-PCR in stool samples collected from healthy layer chickens in the Sichuan Province of China in 2009. Of the 192 stool specimens collected, 32.3% (62/192) were positive for ANV infection. The whole genome of ANV-Sichuan54, the first representative Chinese strain, was 6941 nucleotides in length, including the 5' untranslated region, three open reading frames (ORFs), a 3' UTR, and a poly-(A) tail. Comparative and phylogenetic analyses based on partial RNA-dependent RNA polymerase (ORF1b) demonstrated that the majority of ANV investigations were more closely related to the U.S. ANV strain (DQ324827-324836) than to the G-4260 (AB033998).

In vivo study of four preparative extracts of Clematis terniflora DC. for antinociceptive activity and anti-inflammatory activity in rat model of carrageenan-induced chronic non-bacterial prostatitis

AIM OF THE STUDY

The present study was conducted to evaluate the anti-inflammatory and antinociceptive activities of Clematis terniflora DC. extracts and fractions and to further support its traditional use as Chinese folk medicine in treatment of urinary infections, especially the disease of prostatitis.

MATERIALS AND METHODS

The antinociceptive activity of its water extract (WE), 70% ethanol extract (EE), water eluted part of EE from AB-8 macroporous resin (WEPMR) and 70% ethanol eluted part of EE from AB-8 macroporous resin (EEPMR) was conducted using mice writhing test with different doses. Then the anti-inflammatory activity of the four parts was evaluated on rat models of carrageenan-induced chronic non-bacterial prostatitis (CNP). Preliminary study was taken to determine the phytochemical compositions of the four preparative extracts.

RESULTS

Significant writhing inhibitory effect was found with EE at small (7.5 g/kg body wt.), moderate (15 g/kg body wt.) and large (30 g/kg body wt.) doses (doses here are presented as crude herbs) as well as EEPMR at moderate and large doses by oral administration (OA) (p≤0.01). Data from prostatic index, lecithin microsome density and white blood cell level showed that moderate dose of EE and EEPMR both had significant (p≤0.05 or p≤0.01) inhibition effect on carrageenan-induced inflammation in rat prostate. The HPLC analytical results showed that flavonoids were the main active compounds in WE, EE and EEPMR. And most flavonoids were accumulated into the part of EEPMR by AB-8 macroporous resin leaving only few compounds in WEPMR. No acute toxicity was identified in oral administration of the four parts at a dose of 100g/kg body wt.

CONCLUSIONS

The results described here suggest that extracts of the aerial part of Clematis terniflora DC. might be of therapeutic interest in the treatment of prostatitis.

Study of brain asymmetries in sporadic and familial first episode patients with schizophrenia

Introduction

Although the deviations of brain volume deficits in sporadic and familial first-episode schizophrenia patients (FEP) had been presented, the difference of brain asymmetries remained unidentified.

Objectives

To assess the potential differences of volumetric asymmetries of gray matter (GM) and white matter (WM) between groups.

Aims

To find out the different injury alteration of sporadic FEP and familial FEP.

Methods

42 sporadic and 30 familiar drug-naïve FEP with and 72 matched normal controls (NC) were recruited. Participants were assessed with neuropsychological tests and scanned by a 3.0T MRI to obtain T1-weighted and DTI images. Lateralization distribution maps of GM and WM volume were generated by employing optimized voxel-based morphometry. The asymmetries were analyzed by comparing calculating Laterality Index (LI) voxel by voxel.

Results

All three groups showed similar overall brain torque. Familiar FEP have more regional extensive GM asymmetry brain lesions compared to sporadic FEP. There was no shared regional lesion between two groups. LIGM and LIWM in right superior temporal were negatively correlated. Significant negative correlations were also found between LIGM of left superior parietal lobule and LIWM of right superior parietal lobule, and between LIGM of right inferior parietal lobule and LIWM of left inferior parietal lobule. The asymmetry in distinct brain regions were related to cognitive deficits especially in the domains of language and memory.

Conclusions

The two patient groups had different alteration in injuries of brain asymmetry. Familiar FEP has more GM extensive asymmetry brain region, which may correlate with their high genetic burdens.

Assessment of white matter abnormalities in paranoid schizophrenia and bipolar mania patients from Chengdu, China

Introduction

White matter abnormalities have been repeatedly reported in both schizophrenia and bipolar disorder (BD) diseases from diffusion tensor imaging (DTI) studies respectively, while the empirical evidences about the diagnostic specificity of white matter abnormalities in these disorders are still limited.

Objectives

25 patients with paranoid schizophrenia and 18 patients with bipolar mania were recruited from the in-patient unit of the Mental Health Centre, West China Hospital, China.

Patients were diagnosed according to the criteria of Diagnostic and Statistical Manual of Mental Disorders-Version IV (DSM- IV). 30 healthy controls were recruited from the community by means of leaflets distributed throughout Chengdu city.

Aims

This study sought to investigate the alterations in fractional anisotropy (FA) in white matter throughout the entire brain of patients from Chengdu, China with paranoid schizophrenia and bipolar mania.

Methods

Diffusion tensor imaging (DTI) was used to assess white matter integrity in patients with paranoid schizophrenia and bipolar mania, as well as in normal controls. The differences in FA were measured by use of voxel-based analysis.

Results

Reduced FA was found in the left posterior corona radiate (PCR) in patients with bipolar mania and paranoid schizophrenia compared to the controls. Patients with bipolar mania also showed a significant reduction in FA in right posterior corona radiate and in right anterior thalamic radiation (ATR).

Conclusions

Common abnormalities in the left PCR might imply an overlap in white matter pathology of both diseases and might be related to the shared risk factors for both disorders.

A new pandemic influenza A(H1N1) genetic variant predominated in the winter 2010 influenza season in Australia, New Zealand and Singapore

Pandemic H1N1 influenza virus is of global health concern and is currently the predominant influenza virus subtype circulating in the southern hemisphere 2010 winter. The virus has changed little since it emerged in 2009, however, in this report we describe several genetically distinct changes in the pandemic H1N1 influenza virus. These variants were first detected in Singapore in early 2010 and have subsequently spread through Australia and New Zealand. At this stage, these signature changes in the haemagglutinin and neuraminidase proteins have not resulted in significant antigenic changes which might make the current vaccine less effective, but such adaptive mutations should be carefully monitored as the northern hemisphere approaches its winter influenza season.

Human parechovirus infections in monkeys with diarrhea, China

Information about human parechovirus (HPeV) infection in animals is scant. Using 5' untranslated region reverse transcription-PCR, we detected HPeV in feces of monkeys with diarrhea and sequenced the complete genome of 1 isolate (SH6). Monkeys may serve as reservoirs for zoonotic HPeV transmissions and as models for studies of HPeV pathogenesis.

Human parechovirus infections in monkeys with diarrhea, China

Information about human parechovirus (HPeV) infection in animals is scant. Using 5′ untranslated region reverse transcription–PCR, we detected HPeV in feces of monkeys with diarrhea and sequenced the complete genome of 1 isolate (SH6). Monkeys may serve as reservoirs for zoonotic HPeV transmissions and as models for studies of HPeV pathogenesis.

Immune response to Plasmodium vivax has a potential to reduce malaria severity

Plasmodium falciparum infection causes transient immunosuppression during the parasitaemic stage. However, the immune response during simultaneous infections with both P. vivax and P. falciparum has been investigated rarely. In particular, it is not clear whether the host's immune response to malaria will be different when infected with a single or mixed malaria species. Phenotypes of T cells from mixed P. vivax-P. falciparum (PV-PF) infection were characterized by flow cytometry, and anti-malarial antibodies in the plasma were determined by an enzyme-linked immunosorbent assay. We found the percentage of CD3+delta2+-T cell receptor (TCR) T cells in the acute-mixed PV-PF infection and single P. vivax infection three times higher than in the single P. falciparum infection. This implied that P. vivax might lead to the host immune response to the production of effector T killer cells. During the parasitaemic stage, the mixed PV-PF infection had the highest number of plasma antibodies against both P. vivax and P. falciparum. Interestingly, plasma from the group of single P. vivax or P. falciparum malaria infections had both anti-P. vivax and anti-P. falciparum antibodies. In addition, antigenic cross-reactivity of P. vivax or P. falciparum resulting in antibodies against both malaria species was shown in the supernatant of lymphocyte cultures cross-stimulated with either antigen of P. vivax or P. falciparum. The role of delta2 +/- TCR T cells and the antibodies against both species during acute mixed malaria infection could have an impact on the immunity to malaria infection.

Sequence analysis of an isolate of minute virus of canines in China reveals the closed association with bocavirus

In the present study, we have cloned and sequenced the nearly-full-length genome of minute virus of canines (MVC), SH26, in China. The genome of MVC, 5,132 nucleotides (nts) in length, contains three open reading frames (ORFs), which are 2,325-bp of NS1, 561-bp of NP1 and 2,112-bp of VP1/VP2 encoding three proteins of 774, 186 and 703 residues, respectively. Predicted amino acids sequence of NS1 of MVC has 44% identity with human bocavirus (HBoV) and human boacvirus 2 (HBoV2), NP1 has 48 and 45% identity with HBoV and HBoV2, VP1/VP2 has 45 and 46% identity with HBoV and HBoV2, respectively. Phylogenetic analysis showed that the present Chinese MVC strain was also closely clustered with the previous American and Japanese MVC isolates, and MVCs formed a different branch together with bovine parvovirus and HBoVs from other parvoviruses classified into Parvovirinae.

Transient receptor potential vanilloid type 1 receptor regulates glutamatergic synaptic inputs to the spinothalamic tract neurons of the spinal cord deep dorsal horn

The spinothalamic tract (STT) neurons in the spinal dorsal horn play an important role in transmission and processing of nociceptive sensory information. Although transient receptor potential vanilloid type 1 (TRPV1) receptors are present in the spinal cord dorsal horn, their physiological function is not fully elucidated. In this study, we examined the role of TRPV1 in modulating neuronal activity of the STT neurons through excitatory and inhibitory synaptic inputs. Whole-cell patch-clamp recordings were performed on STT neurons labeled by a retrograde fluorescent tracer injected into the ventral posterior lateral (VPL) nucleus of the thalamus. Capsaicin (1 microM) increased the frequency of miniature excitatory postsynaptic currents (mEPSC) without changing the amplitude or decay time constant of mEPSC. In contrast, capsaicin had no distinct effect on GABAergic miniature inhibitory postsynaptic currents (mIPSC). Capsazepine (10 microM), a TRPV1 receptor antagonist, abolished the effect of capsaicin on mEPSCs. Capsazepine itself did not affect the baseline amplitude and frequency of mEPSC. The effect of capsaicin on mEPSC was also abolished by removal of external Ca(2+), but not by treatment with Cd(2+). Furthermore, capsaicin increased the firing activity of the STT neurons and this increase in neuronal activity by capsaicin was abolished in the presence of non-N-methyl-d-aspartic acid (NMDA) and NMDA receptor antagonists, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) and (R)-amino-5-phosphonovaleric acid (APV). These data suggest that activation of TRPV1 potentiates the glutamate release from excitatory terminals of primary afferent fibers and subsequently increases the neural activity of STT neurons of the rat spinal cord deep dorsal horn.

Hepatitis E virus infection among domestic animals in eastern China

Hepatitis E virus (HEV) is a zoonotic pathogen of which several species of animal were reported as reservoirs. Antibodies to HEV and HEV RNA have been detected in some Chinese population and swine groups but few other domestic animals. In this study, to investigate the HEV prevalence, we tested sera from 788 pigs, 100 cows, 50 goats, 49 horses, 101 pet dogs, 105 chickens, 47 duck and 45 pigeons in eastern China for anti-HEV immunoglobulin G (IgG). We also tested 50% of the swine sera, all of sera from the other domestic animals and 13 Shanghai human sera which were positive for anti-HEV immunoglobulin M (IgM) for HEV RNA using reverse transcriptase-polymerase chain reaction. Our results indicated that 82.5% (222/269) of the sows, 53.9% (104/193) of the 4- to 6-month-old swine, 63.4% (168/265) of the 1- to 3-month-old swine, 55.7% (34/61) of the slaughterhouse swine, 24% (12/50) of the goats, 16.3% (8/49) of the horses, 17.8% (21/101) of the pet dogs, 6% (6/100) of the cows, 12.8% (6/47) of the ducks, 4.4% (2/45) of the pigeons and 1.9% (2/105) of the chickens exhibited positive for anti-HEV IgG. Inhibition assay confirmed the infection with HEV or HEV-like viruses in these domestic animals except pigeons and chickens. From the sera, we isolated 18 swine HEV strains, one horse HEV strain and two human HEV strains. Sequence analysis showed that the horse HEV isolate and one swine isolate belonged to genotype 3. The other isolates belonged to genotype 4. The two human isolates were phylogenetically closely related to eight of the swine isolates. In short, the presence of anti-HEV antibody had been confirmed in several species of domestic animals in eastern China and HEV RNA has been identified in swine, human and horse. This suggested that the authorities should pay more attention to the prevalence of HEV in eastern China.

Extreme genetic diversity of methicillin-resistant Staphylococcus epidermidis strains disseminated among healthy Japanese children

For the past few years, we have been observing the dissemination of methicillin-resistant staphylococci in the community. From 2001 to 2003, an evaluation of nasal samples from 1,285 children in five day-care centers and two kindergartens in three districts in Japan revealed that methicillin-resistant coagulase-negative staphylococci (MRC-NS) have been widely disseminated in the Japanese community. Their prevalence is much greater than community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Forty-nine children (3.81%) were colonized with MRSA, whereas 390 children (30.35%) were colonized with MRC-NS. These MRC-NS strains predominantly harbored a pair of cassette chromosome recombinase types A2 and B2 (ccrAB2). Of these, 40.8% harbored type IVa staphylococcal cassette chromosome mec (SCCmec) elements, a distinct/characteristic type of SCCmec in pandemic clones of CA-MRSA. Interestingly, there was also a high frequency of nontypeable strains which possessed atypical structures compared to previous SCCmec types. Among the MRC-NS, the majority of strains (63.59%) were methicillin-resistant Staphylococcus epidermidis (MRSE). Their genotypes, as judged from pulsed-field gel electrophoresis (PFGE), were highly diverse. They were so diverse that there was no sign of an immediate transmission of any MRSE clone among children in the same institutions. In a previous report, we expounded that a few CA-MRSA clones with distinct SCCmec types were disseminated among children in the same institutions. Au contraire, with the case of CA-MRSE, there was no single genotype of CA-MRSE disseminated among children even in the same institution or class.

Performance and mechanism of methylene blue biosorption on orange peel

Biosorption of Methylene Blue (MB) from aqueous solution using orange peel biosorbent was experimentally investigated. The effects of dye concentration, solution pH, salt concentration and contact time were investigated in a batch model. The results showed that adsorption equilibrium was reached within one hour at two initial MB concentrations (200 and 1000 mg 1(-1)). The uptake of MB was significantly affected by the pH of dye solution. As the pH decreased, the uptake of MB decreased and was zero at pH 2. The Langmuir isotherm model fitted the experimental data well, and the maximum adsorption capacities of the orange peel were 246.8 +/- 10.6 and 370.3 +/- 31.0 mg g(-1) at pH 7 and pH 10, respectively. The uptake of MB was significantly affected by the high concentration of salts. Adsorption of MB onto orange peel was reversible, and the sorption/desorption efficiencies remained almost 100% even up to seven reuse cycles when the biosorbent loss was taken into consideration. The binding sites were identified to be primary carboxyl groups present in orange peel. The main mechanism of MB adsorption is considered to be electrostatic interaction.

Development and validation of microarray-based assay for epidemiological study of MRSA

We have developed a microarray-based assay for the genotyping of Staphylococcus aureus strains. A DNA microarray consisting of 221 genes with 390 oligonucleotide probes was designed to identify characteristic genes or gene alleles of S. aureus. The 221 genes were chosen on the basis of the following criteria: (i) genes used as control for the microarray system, (ii) virulence genes, (iii) resistance genes and their regulators, and (iv) genes constituting genomic islands, e.g., SCCmec. The microarray system was established by determining the method to prepare targets by random-primer labeling with chromosomal DNA and the conditions for hybridization. We verified the system by using DNAs of seven strains, the genome of which has been fully sequenced. Furthermore, the presence of 32 genes and the types of SCCmec elements and coagulase genes carried by another 27 strains were examined and compared with the results of PCR. As a result, the presence or absence of 182 genes out of the 221 genes was verified. Our data showed the usefulness of the oligonucleotide microarray based assay in identifying important marker sets, such as toxin genes, resistance genes, SCCmec elements, and coagulase genes, for the molecular epidemiology of S. aureus.

Over-expression of S100A2 in pancreatic cancer correlates with progression and poor prognosis

Controversy exists regarding the clinical significance of S100A2 in the progression of tumours. In pancreatic cancer, little is known about the role of S100A2. The aim of this study was to clarify the clinical significance of S100A2 expression in pancreatic carcinogenesis. We microdissected invasive ductal carcinoma (IDC) cells from 22 lesions, pancreatic intraepithelial neoplasia (PanIN) cells from five lesions, intraductal papillary mucinous neoplasm (IPMN) cells from 38 lesions, pancreatitis-affected epithelial (PAE) cells from 16 lesions, and normal ductal cells from 18 normal pancreatic tissues. S100A2 expression in 14 pancreatic cancer cell lines, microdissected cells and formalin-fixed paraffin-embedded (FFPE) samples was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Microdissection analyses revealed that IDC cells expressed higher levels of S100A2 than did IPMN, PAE or normal cells (all comparisons, p < 0.007). Cell lines from metastatic sites expressed higher levels of S100A2 than those from primary sites. PanIN cells expressed higher levels of S100A2 than normal cells (p = 0.018). IDC cells associated with poorly differentiated adenocarcinoma expressed higher levels of S100A2 than did IDC cells without poorly differentiated adenocarcinoma (p = 0.006). Analyses of FFPE samples revealed that levels of S100A2 were higher in samples from patients who survived < 1000 days after surgery than in those from patients who survived > 1000 days (p = 0.043). Immunohistochemical analysis was consistent with qRT-PCR. S100A2 may be a marker of tumour progression or prognosis in pancreatic carcinogenesis and pancreatic cancer.

Impact of reduced vancomycin susceptibility on the therapeutic outcome of MRSA bloodstream infections

Background

The aim of this study was to determine whether clinical outcome of patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia was correlated with vancomycin susceptibility of the corresponding strains.

Methods

A retrospective study on MRSA bacteraemia was performed at a teaching hospital between January 1998 and October 2005 by linking vancomycin susceptibility profiles of patients' isolates with hospitalization data.

Results

A total of 20 out of 209 MRSA bacteraemia patients were treated with vancomycin for at least 5 days with adequate trough levels, and fulfilled the study's inclusion and exclusion criteria. Twenty-two S. aureus isolates from these patients' blood cultures were identified as MRSA, including two hetero-VISA from separate patients and two VISA with vancomycin MIC of 4 mg/L from one patient. Between patients who showed 'good' vancomycin response and patients who did not, there was a significant difference (p < 0.01) in their corresponding MRSAs' vancomycin susceptibility expressed by 'area under curve' (AUC) of population analysis. Significant correlations were found between AUC and initial vancomycin therapeutic response parameters of 'days till afebrile' (r = 0.828, p < 0.01) and 'days till CRP ≦ 30% of maximum' (r = 0.627, p < 0.01)

Conclusion

Our study results caution healthcare personnel that early consideration should be given to cases with a poor vancomycin treatment response that could signify the involvement of MRSA with reduced susceptibility to vancomycin.

Fatty acid-dependent expression of the muscle FABP gene - comparative analysis of gene control in functionally related, but evolutionary distant animal systems

The heart is the most fatty acid-dependent muscle in mammals, but flight muscles of birds and insects encounter even higher rates of fatty acid oxidation. The amount of the muscle fatty acid binding protein (H-FABP) found in these muscle reflects their metabolic activities, and increased fatty acid metabolism in endurance exercise increases FABP expression further. We have studied the mechanism of fatty acid-dependent expression of the H-FABP gene, taking advantage of the comparative analysis of gene control in functionally related, but evolutionary distant animal systems, i.e., rat heart and locust flight muscle. Luciferase reporter genes with a full-length promoter ( approximately 1 kb) from either the locust or the rat were strongly expressed in L6 myoblasts, and the expression of both constructs was markedly increased by fatty acid treatment. Because of its stronger induction by fatty acids and the absence of other vertebrate transcription factor binding sites, the locust promoter was advantageous for the identification of a fatty acid response element (FARE), an inverted repeat of a hexanucleotide half site reminiscent of steroid hormone receptor binding sites (IR-3). All mammalian H-FABP promoters contain similar sequences, however in reverse orientation (everted repeats, ER-3). Deletion of the FARE eliminated the fatty acid inducibility completely for the locust promoter, but only partly for its mammalian analogue, perhaps because of additional factors or more complex interactions. In gel shift studies, the element binds nuclear proteins from both rat cells and locust flight muscle, further attesting to the far-reaching conservation of this mechanism. Two individual proteins bind to the element, with full binding requiring the presence of free fatty acid. Antibodies to PPARs failed to induce a supershift of the protein-DNA complex, indicating that other transcription factors are responsible for the fatty acid-mediated induction of gene expression of H-FABP.

Persistent bacteraemia due to methicillin-resistant Staphylococcus aureus with reduced susceptibility to vancomycin in a patient with erythrodermic psoriasis

A 49-y-old male with erythrodermic psoriasis developed persistent bacteraemia for 3 months due to methicillin-resistant Staphylococcus aureus despite antimicrobial therapy. The skin was the likely focus. Three consecutive isolates from the blood and 1 from the nose were identical and had vancomycin MIC of 4 mg/l.

Tissue Engineering and Tissue Repair in Immunocompetent Animals: Tissue Construction and Repair

Tissue engineering can regenerate autologous tissue using a biodegradable scaffold and in vitro expanded cells derived from small biopsy samples, and thus may have great potential for tissue repair and reconstruction in plastic and reconstructive surgery. As an important step towards a clinical application, research work in large animals is essential. This article presents our experience of tissue engineering and repair in large animals in the areas of bone, cartilage and tendon.

An alkaline protease from fresh fruiting bodies of the edible mushroom Pleurotus citrinopileatus

A protease was purified from fresh fruiting bodies of the edible mushroom Pleurotus citrinopileatus. The isolation procedure included ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose and fast protein liquid chromatography-gel filtration on Superdex 75. The protease was unadsorbed on DEAE-cellulose and Q-Sepharose, but adsorbed on CM-cellulose. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protease demonstrated a single band with a molecular mass of 28 kDa. The protease showed an optimal pH at 10 and an optimal temperature at 50 degrees C. The activity of the protease was not affected by EDTA, indicating that it is not a metalloprotease. The protease exhibited a higher activity in the presence of K(+) and Li(+), but its activity was potently inhibited by Al(3+), Cu(2+), and Hg(2+) ions. It manifested a K (m) of 3.44 mg/ml and a V (max) of 0.139 mg ml(-1) min(-1). It was devoid of ribonuclease and antifungal activities.

Subinhibitory concentrations of β-lactam induce haemolytic activity inStaphylococcus aureusthrough the SaeRS two-component system

SaeRS is a two-component system that has been characterized as a positive regulatory system for the expression of several virulence factors, including coagulase, alpha-, beta- and gamma-haemolysins, nuclease, and fibronectin-binding proteins in Staphylococcus aureus. Previously, the SaeRS system was found to be induced at the transcriptional level by beta-lactam. Here, we found that subinhibitory concentrations of beta-lactam induce haemolytic activity in the S. aureus N315 strain but not in the saeRS null mutant KSA. Comparison of the transcriptional profile of the N315 and KSA strains by microarray analysis reveals that the SaeRS system modulates the regulation of coagulase (coa), alpha-, beta- and gamma-haemolysins (hla, hlb and hlg), nuclease (SA0746), fibrinogen-binding proteins (emp, efb, SA1000 and SA1004), fibronectin-binding protein B (fnbB), and 13 other genes. Further, the use of cefoxitin as a signal inducer reveals that the SaeRS system appears to modulate 22 additional genes as a secondary regulon, including the staphylococcal accessory regulators SarA and SarT and the Clp protease ATPase subunits ClpB and ClpL. These observations suggest that beta-lactam is able to induce the SaeRS system, which acts as a crucial signal transduction system for S. aureus pathogenicity rather than antimicrobial resistance.