Crystal structures of Bbp from Staphylococcus aureus reveal the ligand binding mechanism with Fibrinogen α

Bone sialoprotein-binding protein (Bbp), a MSCRAMMs (Microbial Surface Components Recognizing Adhesive Matrix Molecules) family protein expressed on the surface of Staphylococcus aureus (S. aureus), mediates adherence to fibrinogen α (Fg α), a component in the extracellular matrix of the host cell and is important for infection and pathogenesis. In this study, we solved the crystal structures of apo-Bbp(273-598) and Bbp(273-598)-Fg α(561-575) complex at a resolution of 2.03 Å and 1.45 Å, respectively. Apo-Bbp(273-598) contained the ligand binding region N2 and N3 domains, both of which followed a DE variant IgG fold characterized by an additional D1 strand in N2 domain and D1' and D2' strands in N3 domain. The peptide mapped to the Fg α(561-575) bond to Bbp(273-598) on the open groove between the N2 and N3 domains. Strikingly, the disordered C-terminus in the apo-form reorganized into a highly-ordered loop and a β-strand G'' covering the ligand upon ligand binding. Bbp(Ala298-Gly301) in the N2 domain of the Bbp(273-598)-Fg α(561-575) complex, which is a loop in the apo-form, formed a short α-helix to interact tightly with the peptide. In addition, Bbp(Ser547-Gln561) in the N3 domain moved toward the binding groove to make contact directly with the peptide, while Bbp(Asp338-Gly355) and Bbp(Thr365-Tyr387) in N2 domain shifted their configurations to stabilize the reorganized C-terminus mainly through strong hydrogen bonds. Altogether, our results revealed the molecular basis for Bbp-ligand interaction and advanced our understanding of S. aureus infection process.

Inner Canon of Huangdi establishing fundamental theoretical category of TCM:observation / 中华中医药杂志

Observation is a necessary precondition of obtaining and constructing reliable knowledge,through which people can extract nature and low of things and lives from complex phenomenon.Therefore,widely and deeply observation is an important foundation and scienti c method category of forming TCM theoretical system.

Effects of Naps during Sleep Deprivation on Symbols Recognizing Task and P300 / 中国心理卫生杂志

Objective:To study the effect of 30-min nap at three low points of the rhythm during 40-hour sleep deprivation Method:Eight young subjects having normal sleep-wake habits were subjected to nap and total sleep deprivation conditions at an interval of 2 weeks The whole experiment was from 6:00 of the first day to 22:00 totally 40 hours The typing workload was given There were three times of naps, which lasted 30 min every time, at 13:00 (the first day), 1:00 and 13:00 (the second day) Visual event related potentials were measured at 1:00 and the end Symbol recognizing task was given before the experiment, after each nap, at the end of it, and two days after Results:In the symbols recognizing task, whether sleep deprivation with or without naps, the reactive time prolonged, the number of right decreased, the number of lose increased Compared with total sleep deprivation, the reactive time was shortened apparently while the number of right and lose did not change when naps were introduced Whether sleep deprivation with or without naps, the latency of P300 was prolonged, the number of right decreased while the amplitude did not change Compared with total sleep deprivation, the latency was shortened apparently while the number of right and amplitude did not change when having naps Conclusion:Nap has positive effects during sleep deprivation

Relative study of event-related potentials elicited by calculating and number recognizing / 临床神经病学杂志

Objective To investigate the relation of event-related potentials (ERPs), which are evoked by calculating and number recognizing stimuli.Methods We examined 26 healthy undergraduate students with double-digit (Arabic numbers) and single-digit modify a prescription problems. While the stimulus information was presented, electroencephalogram (EEG) was recorded simultaneously. ERPs were extracted from EEG data, and then the feature and source of ERPs were analyzed.Results Both calculation and number recognizing induced positive and negative components of ERPs with similar wave form and different latency. The latency of ERPs was conspicuously shorter elicited by number recognizing than by calculating. Grand mean mapping showed the highest amplitudes of ERPs were presented in parietal lobe elicited both by calculating and number recognizing.Conclusion The processing of calculating is more complicated than number recognizing. Calculating and number recognizing may have different electrophysiological background, and they belong to diverse processing course in the brain. Parietal lobe is the functional domains of them.

Establishment of OVS3 monoclonal antibody recognizing human ovarian cancer.

OVS3 monoclonal antibody (MAb) was established by fusing murine myeloma cell line NS 1/1-Ag 4-1 with spleen cells from mouse immunized with fresh ovarian endometrioid carcinoma. The MAb was selected by a specific immunohistological (streptavidin-biotin) staining on the tumor area of frozen sections of the same tumor. The immunohistological staining with OVS3 MAb was also screened on frozen sections of 21 normal tissues, 5 benign tumors, 20 ovarian cancers and 5 other cancers. The positive result was 50% in all ovarian cancers compared to almost negative results in the other groups (97% specificity). The heat labile property of OVS3 antigen (Ag) was found when hegative staining results were shown in all paraffin sections in spite of positive reactions on frozen sections of the same tumors. The OVS3 Ag was confirmed to be a 3-subunit protein of 40-50 kD molecular weight by the immunoprecipitation technique. The data supported OVS3 MAb as another new MAb recognizing an epitope different from the previously established OVS1 and OVS2 MAbs.