Visualizing an ultra-weak protein-protein interaction in phosphorylation signaling.

Proteins interact with each other to fulfill their functions. The importance of weak protein-protein interactions has been increasingly recognized. However, owing to technical difficulties, ultra-weak interactions remain to be characterized. Phosphorylation can take place via a K(D)≈25 mM interaction between two bacterial enzymes. Using paramagnetic NMR spectroscopy and with the introduction of a novel Gd(III)-based probe, we determined the structure of the resulting complex to atomic resolution. The structure accounts for the mechanism of phosphoryl transfer between the two enzymes and demonstrates the physical basis for their ultra-weak interaction. Further, molecular dynamics (MD) simulations suggest that the complex has a lifetime in the micro- to millisecond regimen. Hence such interaction is termed a fleeting interaction. From mathematical modeling, we propose that an ultra-weak fleeting interaction enables rapid flux of phosphoryl signal, providing a high effective protein concentration.

[Impact of artificial reef on community of macrobenthos in Jincheng area of Laizhou Bay, China].

In order to evaluate the impact of artificial reef on the communities of macrobenthos, from 2009 to 2012, samples were collected in four seasons at the artificial reef area and the control area in Jincheng area of Laizhou Bay from 9 cruises. A total of 35 macrobenthos species (4 phyla, 30 families) were recorded in the two areas, with 30 species in the artificial reef area, and 27 species in the control area. Results suggested that the two macrobenthos communities with different species composition could be discriminated. One community was located in artificial reef area, the other outside the reef area. Planktophagous group was the most dissimilarity-contributing species. The species similarity (Jaccard) of the two areas increased from 37.5% in the first year to 58.6% in the second year. The biomass and abundance of macrobenthos in the artificial reef area respectively increased from 1.00 g · m(-2) and 540 ind · m(-2) in the first year to 1.55 g · m(-2) and 622 ind · m(-2) in the second year, which were both higher than those in the control area. Compared with the control area, the Shannon index and abundance index of the artificial reef area were increased, while the evenness index was decreased. The abundance biomass comparison (ABC) curve showed that the macrobenthos communities were more heavily disturbed in the second year than that in the first year after artificial reef set. It was considered that the macrobenthos community was unsteady at the early stage after artificial reef construction (1-2 years). The physical, chemical, biological and human activities were the main factors influencing macrobenthos community in Jincheng area of Laizhou Bay.

[Ten years outcome observation of infants with hepatitis C virus mother to infant transmission].

OBJECTIVE: To study the outcome of hepatitis C virus (HCV) vertical transmitted infants. METHODS: Thirteen HCV vertical infected infants were followed up for 10 years. HCV antibody and HCV RNA in the blood samples from them were tested using second generation HCV antibody EIA kits and RT-PCR, respectively. RESULTS: Among the 13 infants, one developed clinical hepatitis C, and serum HCV antibody and HCV RNA could be detected for 7 and 8 years, respectively. Three were subclinical hepatitis C, serum HCV antibody continued to be positive for 12 months (2 infants) and 24 months (1 infant), respectively, and serum HCV RNA turned to be negative at the 24th month (2 infants) and the 60th month (1 infant), respectively. Nine were HCV insidious infection, whose serum HCV antibody and HCV RNA turned to be negative in 12 months. During the eight to ten years, there was no infants with anti-HCV or HCV RNA positive again. CONCLUSIONS: It is rarely happened that vertical transmitted HCV induce chronic HCV carrying state and chronic viral hepatitis, and most of the infected infants have good outcome.