肾小球疾病与机能蛋白

随着分子生物学技术的不断发展和进步,人们已能在基因水平上对肾小球疾病的发生机制与发展进程加以详尽的阐明。但DNA本身并不具有生物学活性,其所含的生物遗传信息须经转录传递给信使RNA(mRNA),再由mRNA翻译形成具有生物学功能的蛋白。这些被称作机能蛋白的蛋白可参与细胞间的信息交换以及细胞间网络系统的形成,从而引起肾小球疾病的发生和发展。

机能性丝蛋白的利用与研究进程

由于生丝具有良好的风貌与优雅的光泽,并且在染色性、吸湿性与排湿性等方面都有其优良的特性,因此,几千年来,人们一直把它作为一种加工高级衣料的素材。为了探明生丝本身具有的优良的物理特性与化学特性的机理,或是出于对昆虫的生物高分子的结构产生了科学探索的兴趣,长期以来,人们就对丝蛋白的结构与物性作了研究。直至目前,对丝蛋白的结晶结构以及高级结构等的全貌,尚未获得阐明,而对特异结构所产生的多种机能特性,亦正处于探索之中。目前人们所期待的是,能将生丝用途扩大到衣料素材以外的各个领域;也就是说,主要目标是放在将丝蛋白作为“生物工程”的一种素材,在非衣料素材的领域,积极开发其新的用途。

Protein profile of human hepatocarcinoma cell line SMMC-7721:Identification and functional analysis

AIM： TO investigate the protein profile of human hepatocarcinoma cell line SMMC-7721, to analyze the specific functions of abundant expressed proteins in the processes of hepatocarcinoma genesis, growth and metastasis, to identify the hepatocarcinoma-specific biomarkers for the early prediction in diagnosis, and to explore the new drug targets for liver cancer therapy. METHODS： Total proteins from human hepatocarcinoma cell line SMMC-7721 were separated by two-dimensional electrophoresis （2DE）. The silver-stained gel was analyzed by 2DE software Image Master 2D Elite. Interesting protein spots were identified by peptide mass fingerprinting based on matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry （MALDI-TOF-MS） and database searching. RESULTS： We obtained protein profile of human hepatocarcinoma cell line SMMC-7721. Among the twenty-one successfully identified proteins, mitofilin, endoplasmic reticulum protein ERp29, ubiquinol-cytochrome C reductase complex core protein I, peroxisomal enoyl CoA hydratase, peroxiredoxin-4 and probable 3-oxoacid CoA transferase 1 precursor were the six novel proteins identified in human hepatocarcinoma cells or tissues. Specific functions of the identified heat-shock proteins were analyzed in detail, and the results suggested that these proteins might promote tumorigenesis via inhibiting cell death induced by several cancer-related stresses or via inhibiting apoptosis at multiple points in the apoptotic signal pathway. Other identified chaperones and cancer-related proteins were also analyzed.CONCLUSION： Based on the protein profile of SMMC-7721 cells, functional analysis suggests that the identified chaperones and cancer-related proteins have their own pathways to contribute to the tumorigenesis, tumor growth and metastasis of liver cancer. Furthermore, proteomic analysis is indicated to be feasible in the cancer study.

Giardia infection:Protein-losing enteropathy in an adult with immunodeficiency

The case of a 52-year-old woman with a past history of thymoma resection who presented with chronic diarrhea and generalized edema is the focal point of this article.A diagnosis of Giardia lamblia infection was established,which was complicated by protein-losing enteropathy and severely low serum protein level in a patient with no urinary protein loss and normal liver function.After anti-helmintic treatment,there was recovery from hypoalbuminemia,though immunoglobulins persisted at low serum levels leading to the hypothesis of an immune system disorder.Good's syndrome is a rare cause of immunodeficiency characterized by the association of hypogammaglobulinemia and thymoma.This primary immune disorder may be complicated by severe infectious diarrhea secondary to disabled humoral and cellular immune response.This is the first description in the literature of an adult patient with an immunodeficiency syndrome who presented with protein-losing enteropathy secondary to giardiasis.

Performance of the Bean-protein Fiber

The methods in testing the bean-protein fiber and the standards used were simply introduced. The fiber's mechanical and chemical performances were further analyzed. And the correlative performance of the bean-protein fibers and other natural fibers have been compared, then full knowledge of the fiber's performance was concluded.

CLINICAL OBSERVATION ON THERAPEUTIC EFFECT OF ACUPUNCTURE AT ZUSANLI FOR LEUKOPENIA

In recent years, leukopenia is clinically very common. The leukopenic patient is significantly low in immunocompetence and is likely to suffer from various kinds of infections. Zusanli (St 36), an

Aquaporin 5 is degraded by autophagy in diabetic submandibular gland

Autophagy is a catabolic process which is involved in the development of many diseases including diabetes mellitus and its complications. Hyposalivation is a common complication of diabetes mellitus, whereas its mechanism remains unclear. Here, we observed that the stimulated salivary flow rate of SMG was significantly decreased in db/db mice, a diabetic mice model. The expressions of aquaporin 5(AQP5), a water channel protein, were decreased, whereas the m RNA level of AQP5 was increased in SMGs of both diabetic patients and mice. Under transmission electron microcope, more autophagosomes were detected in diabetic SMGs. Expressions of autophagy related proteins LC3 II, Beclin-1 and ATG5 were increased, meanwhile autophagy substrate p62 was decreased in SMGs of diabetic patients and mice, indicating that autophagy was activated in diabetic SMG.Double immunofluorescence staining showed that the colocalization of AQP5 and LC3 was increased in SMGs of diabetic mice.In cultured SMG-C6 cells, high glucose(HG), but not high osmotic pressure, reduced AQP5 protein expression and induced autophagy. Moreover, inhibition of autophagy by 3-methyladenin, an autophagy inhibitor, or by autophagy-related gene 5 siRNA, decreased HG-induced AQP5 reduction in SMG-C6 cells. Additionally, the expression of p-p85, p-Akt and p-mTOR were decreased in HG-treated SMG-C6 cells. Pretreatment with 740 Y-P, a PI3 K agonist, significantly suppressed HG-induced autophagy and AQP5 degradation. Taken together, these results indicate that autophagy plays a crucial role in AQP5 degradation in diabetic SMG via PI3 K/Akt/mTOR signaling pathway, which contributes to the dysfunction of diabetic SMG. Our study provides a novel mechanism of diabetic hyposalivation.

A potential strategy for treating atherosclerosis： improving endothelial function via AMP-activated protein kinase

Endothelial dysfunction is caused by many factors, such as dyslipidemia, endoplasmic reticulum(ER) stress, and inflammation.It has been demonstrated that endothelial dysfunction is the initial process of atherosclerosis. AMP-activated protein kinase(AMPK) is an important metabolic switch that plays a crucial role in lipid metabolism and inflammation. However, recent evidence indicates that AMPK could be a target for atherosclerosis by improving endothelial function. For instance, activation of AMPK inhibits the production of reactive oxygen species induced by mitochondrial dysfunction, ER stress, and NADPH oxidase. Moreover, activation of AMPK inhibits the production of pro-inflammatory factors induced by dyslipidemia and hyperglycemia and restrains production of perivascular adipose tissue-released adipokines. AMPK activation prevents endothelial dysfunction by increasing the bioavailability of nitric oxide. Therefore, we focused on the primary risk factors involved in endothelial dysfunction, and summarize the features of AMPK in the protection of endothelial function, by providing signaling pathways thought to be important in the pathological progress of risk factors.

Defect-related luminescent bur-like hydroxyapatite microspheres induced apoptosis of MC3T3-E1 cells by lysosomal and mitochondrial pathways

When orthopedic joints coated by hydroxyapatite(HA) were implanted in the human body, they release wear debris into the surrounding tissues. The generation and accumulation of wear particles will induce aseptic loosening. However, the potential bioeffect and mechanism of HA-coated orthopedic implants on bone cells are poorly understood. In this study, defect-related luminescent bur-like hydroxyapatite(BHA) microspheres with the average diameter of 7–9 μm which are comparable to that of the wear-debris particles from aseptically loosened HA implants or HA debris have been synthesized by hydrothermal synthesis and the MC3 T3-E1 cells were set as a cells model to study the potential bioeffect and mechanism of BHA microspheres. The studies demonstrated that BHA microspheres could be taken into MC3 T3-E1 cells via endocytosis involved in micropinocytosisand clathrin-mediated endocytosis process, and exert cytotoxicity effect. BHA microspheres could induce the cell apoptosis by intracellular production of reactive oxygen species(ROS), which led to not only an increase in the permeability of lysosome and release of cathepsins B, but also mitochondrial dysfunction and DNA damage. Our results provide novel evidence to elucidate their toxicity mechanisms and might be helpful for more reasonable applications of HA-based orthopaedic implants in the future.

RECOGNITION OF STRUCTURE SIMILARITIES IN PROTEINS

Protein fold structure is more conserved than its amino acid sequence and closely associated with biological function, so calculating the similarity of protein structures is a fundamental problem in structural biology and plays a key role in protein fold classification, fold function inference, and protein structure prediction. Large progress has been made in recent years in this field and many methods for considering structural similarity have been proposed, including methods for protein structure comparison, retrieval of protein structures from databases, and ligand binding site comparison. Most of those methods can be available on the World Wide Web, but evaluation of all the methods is still a hard problem. This paper summarizes some popular methods and latest methods for structure similarities, including structure alignment, protein structure retrieval, and ligand binding site alignment.