Regulation of K+ channels in the basolateral membrane ofNecturus oxyntic cells

Summary Patch-clamp methods were used to study single-channel events in isolated oxyntic cells and gastric glands fromNecturus maculosa. Cell-attached, excised inside-out and outside-out patches from the basolateral membrane frequently contained channels which had conductances of 67±21 pS in 24% of the patches and channels of smaller conductance, 33±6 pS in 56% of the patches. Channels in both classes were highly selective for K⁺ over Na⁺ and Cl^–, and shared linear current-voltage relations. The 67-pS channel was activated by membrane depolarization, whereas the activity of the 33-pS channel was relatively voltage independent. The larger conductance channels were activated by intracellular Ca²⁺ in the range between 5 and 500nm, but unaffected by cAMP. The smaller conductance channels were activated by cAMP, but not Ca²⁺. The presence of K⁺ channels in the basolateral membrane which are regulated by these known second messengers can account for the increase in conductance and the hyperpolarization of the membrane observed upon secretagogue stimulation.     

中间载体pBz6102的构建及CAT基因在转化烟草中的表达

来源于细菌的新霉素磷酸转移酶基因(NPT),氯霉素乙酰转移酶基因(CAT)以及来源于昆虫的荧光素酶基因等都是用于研究根癌农杆菌转化植物的良好标记。我们利用氯霉素乙酰转移酶嵌合基因和来源于Ti质粒T-区DNA的tmr基因,构建了中间载体pBZ 6102,并通过植物基因工程载体pGV 3850,将氯霉素乙酰转移酶嵌合基因和tmr基因引入了植物细胞,并测到了表达,在抗氯霉素植物中测到了氯霉素乙酰转移酶活性。中间裁体pBZ 6102上还有Pst Ⅰ,Xba Ⅰ等单一的限制性内切酶位点,外源基因极易插入。转化植物F_1代的种子抗性分析表明,80%左右的种子都能在含氯霉素的培养基上正常萌发,它们的幼苗中都有氯霉素乙酰转移酶活性,证明CAT基因通过了减数分裂稳定地保留在植物细胞的基因组内。     

Phosphoglucomutase-1 polymorphism among Chinese in Taiwan.

Phosphoglucomutase-1 (PGM1) phenotyping of 1,128 Chinese blood donors was performed by thin-layer isoelectric focusing on agarose. The PGM1 gene frequencies were: 1A, 0.6005; 1B, 0.1500; 2A, 0.1510; 2B, 0.0973, and rare variants, 0.0058. The rare variants found in this series were PGM1 W21, W2, W3, W6 and W9 (or W10) with PGM1 W21 being the most common variant among Chinese with a phenotype frequency of 0.8%.     

The mitochondrial targeting chaperone 14-3-3ε regulates a RIG-I translocon that mediates membrane association and innate antiviral immunity

RIG-I is a cytosolic pathogen recognition receptor that initiates immune responses against RNA viruses. Upon viral RNA recognition, antiviral signaling requires RIG-I redistribution from the cytosol to membranes where it binds the adaptor protein, MAVS. Here we identify the mitochondrial targeting chaperone protein, 14-3-3ε, as a RIG-I-binding partner and essential component of a translocation complex or "translocon" containing RIG-I, 14-3-3ε, and the TRIM25 ubiquitin ligase. The RIG-I translocon directs RIG-I redistribution from the cytosol to membranes where it mediates MAVS-dependent innate immune signaling during acute RNA virus infection. 14-3-3ε is essential for the stable interaction of RIG-I with TRIM25, which facilitates RIG-I ubiquitination and initiation of innate immunity against hepatitis C virus and other pathogenic RNA viruses. Our results define 14-3-3ε as a key component of a RIG-I translocon required for innate antiviral immunity.     

Spinal macrophages resolve nociceptive hypersensitivity after peripheral injury

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Pancreatic polypeptide causes diarrhea and weight loss in obese mice but not in lean littermates

Pancreatic polypeptide was infused into obese-hyperglycemic (ob/ob) mice and lean littermates to determine its effect on weight gain. Obese mice continuously infused with 30, 60, or 100 μg/day for 7 days developed both diarrhea and weight loss in a dose dependent fashion. Lean littermates infused with 100 μg/day developed neither diarrhea nor weight loss. Light microscopic study of ileum and colon revealed no abnormalities. These studies indicate that the effects of pancreatic polypeptide are in part genetically determined since the obese and non-obese mice differ at only one gene locus.     

Gas chromatographic determination of aromatic acid metabolites of phenylalanine in brain

A method for the determination of the aromatic acid metabolites of phenylalanine in brain by gas-liquid chromatography is described. Procedures were developed for the extraction and purification of the metabolites, the preparation of their trimethylsilyl derivatives, the separation and identification of these derivatives by gas-liquid chromatography, and the quantification of the metabolites by employing the internal reference standards phenylvaleric and o-hydroxyphenylacetic acids with the detector molar response factors. The metabolites in the hyperphenylalaninemic brain were identified as the trimethylsilyl ester of phenylacetic, ester-ethers of mandelic and phenyllactic, and the ester-enol ether of the oxime of phenylpyruvic acid.     

Fibrotic enzymes modulate wound‐induced skin tumorigenesis

Fibroblasts are a major component of the microenvironment of most solid tumours. Recent research elucidated a large heterogeneity and plasticity of activated fibroblasts, indicating that their role in cancer initiation, growth and metastasis is complex and context‐dependent. Here, we performed genome‐wide expression analysis comparing fibroblasts in normal, inflammatory and tumour‐associated skin. Cancer‐associated fibroblasts (CAFs) exhibit a fibrotic gene signature in wound‐induced tumours, demonstrating persistent extracellular matrix (ECM) remodelling within these tumours. A top upregulated gene in mouse CAFs encodes for PRSS35, a protease capable of collagen remodelling. In human skin, we observed PRSS35 expression uniquely in the stroma of high‐grade squamous cell carcinomas. Ablation of PRSS35 in mouse models of wound‐ or chemically‐induced tumorigenesis resulted in aberrant collagen composition in the ECM and increased tumour incidence. Our results indicate that fibrotic enzymes expressed by CAFs can regulate squamous tumour initiation by remodelling the ECM.