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K C Cheah  S Sankar  A G Porter 《Gene》1988,69(2):265-274
Human rhinovirus serotype-14 (HRV-14) cDNA, encompassing 87.9% of the coding region, was subcloned in an Escherichia coli expression vector, generating plasmid pKCC101. HRV-14 polypeptides encoded by pKCC101 were synthesized in E. coli maxicells. Pulse-chase experiments with pKCC110, a smaller derivative of pKCC101 containing the protease 3C coding region, have clearly demonstrated the proteolysis of a 55-kDa precursor to several polypeptides, including a doublet with the expected size of protease 3C (20 kDa). The proteolysis of the 55-kDa precursor polypeptide was prevented by ZnCl2, a known inhibitor of picornavirus 3C proteases. Results with a derivative of pKCC110 (pKCC115) which is partially deleted for the protease 3C sequence, support the idea that the doublet proteins are specified by the protease 3C coding region. Taken together, our investigations indicate that the precursor form of protease 3C must be responsible for its own cleavage.  相似文献   
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It has been suggested that community advisory boards (CABs) can play a role in minimising exploitation in international research. To get a better idea of what this requires and whether it might be achievable, the paper first describes core elements that we suggest must be in place for a CAB to reduce the potential for exploitation. The paper then examines a CAB established by the Shoklo Malaria Research Unit under conditions common in resource‐poor settings – namely, where individuals join with a very limited understanding of disease and medical research and where an existing organisational structure is not relied upon to serve as the CAB. Using the Tak Province Border Community Ethics Advisory Board (T‐CAB) as a case study, we assess the extent to which it might be able to take on a role minimising exploitation were it to decide to do so. We investigate whether, after two years in operation, T‐CAB is capable of assessing clinical trials for exploitative features and addressing those found to have them. The findings show that, although T‐CAB members have gained knowledge and developed capacities that are foundational for one‐day taking on a role to reduce exploitation, their ability to critically evaluate studies for the presence of exploitative elements has not yet been strongly demonstrated. In light of this example, we argue that CABs may not be able to perform such a role for a number of years after initial formation, making it an unsuitable responsibility for many short‐term CABs.  相似文献   
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1. The effect of fuscin on the mitochondrial oxidation of pyruvate plus malate, of succinate and of ascorbate plus tetramethyl-p-phenylenediamine (TMPD) and on the redox changes of succinate-reducible cytochromes b and c was investigated using tightly-coupled ox-neck muscle mitochondria.  相似文献   
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Heterozygous missense mutations in IHH result in Brachydactyly type A1 (BDA1; OMIM 112500), a condition characterized by the shortening of digits due to hypoplasia/aplasia of the middle phalanx. Indian Hedgehog signaling regulates the proliferation and differentiation of chondrocytes and is essential for endochondral bone formation. Analyses of activated IHH signaling in C3H10T1/2 cells showed that three BDA1-associated mutations (p.E95K, p.D100E and p.E131K) severely impaired the induction of targets such as Ptch1 and Gli1. However, this was not a complete loss of function, suggesting that these mutations may affect the interaction with the receptor PTCH1 or its partners, with an impact on the induction potency. From comparative microarray expression analyses and quantitative real-time PCR, we identified three additional targets, Sostdc1, Penk1 and Igfbp5, which were also severely affected. Penk1 and Igfbp5 were confirmed to be regulated by GLI1, while the induction of Sostdc1 by IHH is independent of GLI1. SOSTDC1 is a BMP antagonist, and altered BMP signaling is known to affect digit formation. The role of Penk1 and Igfbp5 in skeletogenesis is not known. However, we have shown that both Penk1 and Igfbp5 are expressed in the interzone region of the developing joint of mouse digits, providing another link for a role for IHH signaling in the formation of the distal digits.  相似文献   
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In nature, an oxo‐bridged Mn4CaO5 cluster embedded in photosystem II (PSII), a membrane‐bound multi‐subunit pigment protein complex, catalyzes the water oxidation reaction that is driven by light‐induced charge separations in the reaction center of PSII. The Mn4CaO5 cluster accumulates four oxidizing equivalents to enable the four‐electron four‐proton catalysis of two water molecules to one dioxygen molecule and cycles through five intermediate S‐states, S0 – S4 in the Kok cycle. One important question related to the catalytic mechanism of the oxygen‐evolving complex (OEC) that remains is, whether structural isomers are present in some of the intermediate S‐states and if such equilibria are essential for the mechanism of the O‐O bond formation. Here we compare results from electron paramagnetic resonance (EPR) and X‐ray absorption spectroscopy (XAS) obtained at cryogenic temperatures for the S2 state of PSII with structural data collected of the S1, S2 and S3 states by serial crystallography at neutral pH (~6.5) using an X‐ray free electron laser at room temperature. While the cryogenic data show the presence of at least two structural forms of the S2 state, the room temperature crystallography data can be well‐described by just one S2 structure. We discuss the deviating results and outline experimental strategies for clarifying this mechanistically important question.  相似文献   
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