Staphylococcus aureus is a major cause of hospital-acquired infection. Because the bacteria are very easy to become resistant to antibiotics, vaccination is a main method against S. aureus infection. Clumping factor B (ClfB) is an adhesion molecule essential for S. aureus to colonize in the host mucosa and is regarded as an important target antigen. In this study, we successfully used Escherichia coli to express a segment encoding the N1-N3 regions of ClfB protein (Truncated-ClfB) cloned from S. aureus. The protein was purified by affinity and ion exchange chromatographies and gel filtration. Rabbits were immunized three times with purified Truncated-ClfB. After that, blood was collected to prepare serum which were then used for measurement of antibody level. Phagocytosis of S. aureus opsonized by the serum was determined by a flow cytometry. Results show that the serum IgG titer reached 1:640 000. Phagocytosed S. aureus by polymorphonuclear leukocytes were significantly more when the bacteria were opsonized by the serum from Truncated-ClfB immunized rabbits than those from no immunized group (P < 0.01). Therefore, the results indicated that Truncated-ClfB could be a promising vaccine candidate against S. aureus infection.
Adhesins, Bacterial ; immunology ; Animals ; Antibodies, Bacterial ; blood ; Escherichia coli ; Flow Cytometry ; Immune Sera ; Immunoglobulin G ; blood ; Opsonin Proteins ; immunology ; Phagocytosis ; Rabbits ; Staphylococcal Infections ; immunology ; Staphylococcus aureus

Objective To evaluate the cardioprotection induced by ischemic preconditioning ( IPC) and hypoxic preconditioning ( HPC) which were carried out by using the double cardiopulmonary bypass ( CPB) circuits in in vivo hearts of dogs. Methods Eighteen healthy male dogs, weighing 17?5-24?5 kg, aged 13-24 months, were divided into 3 groups ( n=6 each) using a random number table: my?ocardial ischemia?reperfusion group (group I∕R), IPC group and HPC group. The double CPB circuits were established as follows: systemic and coronary circulation, and independent systemic and coronary cir?culation was carried out. In group IPC, the aorta was clamped, and the coronary circulation pump was sus?pended for 5 min followed by 5 min opening, repeating for 3 cycles. In group HPC, the aorta was clamped, the coronary circulation was started, and pure nitrogen was insufflated for 5 min followed by 5 min of oxygen insufflation, repeating for 3 cycles. CPB was performed for 1 h starting from the time point immediately after IPC or HPC. Before splitting of sternum ( T1 ) , after establishment of double CPB circuits ( T2 ) , at the end of preconditioning ( T3 ) , and at 60 and 120 min after restoration of spontaneous heart
beat ( T4,5 ) , heat rate, mean arterial pressure, central venous pressure, left ventricular end?systolic pres?sure, left ventricular end?diastolic pressure and the maximum rate of increase∕decrease of left ventricular pressure were recorded. Blood samples were collected from the right internal jugular vein at T1 and T4,5 for determination of serum cardiac troponin I concentrations. The animals were sacrificed after determination of the parameter or after blood sampling at T5 , myocardial specimens were obtained for examination of the ul?trastructure and for detection of apoptosis in cardiomyocytes, and apoptosis index was calculated. Before aortic clamping, immediately after aortic unclamping and at 30 min after aortic unclamping, myocardial specimens were obtained for determination of ATP contents in cardiomyocytes. Results Compared with I∕R group, left ventricular end?systolic pressure was significantly increased, and the serum cardiac troponin I concentrations were significantly decreased at T4,5 , the myocardial ATP contents were significantly in?creased immediately after aortic unclamping and at 30 min after aortic unclamping, apoptosis index was sig?nificantly decreased ( P<0?05 or 0?01) , and the pathological changes were significantly attenuated in IPC and HPC groups. Compared with group IPC, the myocardial ATP contents were significantly increased (P<0?05), and the pathological changes were attenuated in group HPC. Conclusion Both HPC and IPC can exert cardioprotection when carried out by using the double CPB circuits, and HPC provides better cardioprotection than IPC in in vivo hearts of dogs.

BACKGROUNDTo investigate the origin of tumor blood vessel and blood supply during pulmonary carcinogenesis, and the relationship between vascular endothelial growth factor (VEGF), its receptor Flk-1 and angiogenesis.

METHODSOne hundred Wistar rats were instilled with 3-methylcholanthrene (MCA) and diethylinitrosamine (DEN) to induce pulmonary squamous cell carcinoma through left lower lobe bronchus. To acquire different pathological phase during the carcinogenesis, rats were killed in 15, 35, 55, 65, 75 days after instillation. Yellow and green silastics were respectively injected into the bronchial and pulmonary arteries of 30 rats in 55, 65, 75 days after instillation. Intertumor microvessel density (MVD) was marked by anti-von Willebrand factor monoantibody. VEGF and Flk-1 expression were examined by immunohistochemistry.

RESULTSIn the tumor area the tumor blood vessels were yellow and connected with distorted bronchial artery and very few green incomplete branches of pulmonary artery were seen. Silastic particles could be seen in the disordered tumor blood vessels by microscope after bronchial artery perfusion. There was no silastic particles in the carcinoma interstitial blood vessels after pulmonary artery perfusion. MVD count significantly increased in carcinoma in situ (39.50±12.60) and infiltrative carcinoma (61.05±19.92) as compared to atypical hyperplasia (8.92±3.80)(both P < 0.01), and the increased vessels originated from bronchial artery, but not pulmonary artery. The expression of VEGF and Flk-1 increased during pulmonary carcinogenesis. The positive coefficients of VEGF and FLK-1 expressions became higher and higher from epithelial proliferation to squamous metaplasia, to atypical hyperplasia, to carcinoma in situ and finally to infiltrative carcinoma. There was significant correlation between MVD and VEGF expression (r=0.979 8, P < 0.005), as well as between MVD and Flk-1 expression (r=0.907 8, P < 0.05).

CONCLUSIONSAngiogenesis is the important phenomenon of the rat pulmonary carcinogenesis and the newly formed blood vessels in tumor connect with the branches of bronchial artery, but not pulmonary artery. This confirms that the blood supply of pulmonary carcinoma is from bronchial artery, not from pulmonary artery. VEGF and Flk-1 are closely related to angiogenesis of tumor.

There is a great need for new vaccine development against influenza A viruses due to the drawbacks of traditional vaccines that are mainly prepared using embryonated eggs. The main component of the current split influenza A virus vaccine is viral hemagglutinin (HA) which induces a strong antibody-mediated immune response. To develop a modern vaccine against influenza A viruses, the current research has been focused on the universal vaccines targeting viral M2, NP and HA proteins. Crystallographic studies have shown that HA forms a trimer embedded on the viral envelope surface, and each monomer consists of a globular head (HA1) and a "rod-like" stalk region (HA2), the latter being more conserved among different HA subtypes and being the primary target for universal vaccines. In this study, we rationally designed the HA head based on the crystal structure of the 2009-pandemic influenza A (H1N1) virus HA as a model, tested its immunogenicity in mice, solved its crystal structure and further examined its immunological characteristics. The results show that the HA globular head can be easily prepared by in vitro refolding in an E. coli expression system, which maintains its intact structure and allows for the stimulation of a strong immune response. Together with recent reports on some similar HA globular head preparations we conclude that structure-based rational design of the HA globular head can be used for subtype-specific vaccines against influenza viruses.
Animals ; Antibodies, Viral ; immunology ; Crystallography, X-Ray ; Drug Design ; Female ; Freund's Adjuvant ; administration & dosage ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; immunology ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; immunology ; Influenza Vaccines ; administration & dosage ; biosynthesis ; Influenza, Human ; immunology ; prevention & control ; virology ; Mice ; Mice, Inbred BALB C ; Models, Molecular ; Protein Folding ; Recombinant Proteins ; genetics ; immunology ; Structure-Activity Relationship ; Vaccination ; Vaccines, Subunit ; administration & dosage ; biosynthesis

Bacterial cell division is strictly regulated in the formation of equal daughter cells. This process is governed by a series of spatial and temporal regulators, and several new factors of interest to the field have recently been identified. Here, we report the requirement of gluconate 5-dehydrogenase (Ga5DH) in cell division of the zoonotic pathogen Streptococcus suis. Ga5DH catalyzes the reversible reduction of 5-ketogluconate to D-gluconate and was localized to the site of cell division. The deletion of Ga5DH in S. suis resulted in a plump morphology with aberrant septa joining the progeny. A significant increase was also observed in cell length. These defects were determined to be the consequence of Ga5DH deprivation in S. suis causing FtsZ delocalization. In addition, the interaction of FtsZ with Ga5DH in vitro was confirmed by protein interaction assays. These results indicate that Ga5DH may function to prevent the formation of ectopic Z rings during S. suis cell division.
Bacterial Proteins ; chemistry ; genetics ; metabolism ; Cell Division ; Cell Shape ; Cytoskeletal Proteins ; chemistry ; genetics ; metabolism ; Mutation ; Oxidoreductases ; deficiency ; genetics ; metabolism ; Protein Binding ; Streptococcus suis ; enzymology