反义端粒酶PNA对肺癌细胞株生长的体外抑制作用

目的　探讨反义端粒酶肽核酸 (PNA)片段对肺癌细胞株端粒酶活性及细胞株生长的抑制作用。方法　将人工合成的端粒酶反义PNA片段 ,应用脂质体转染法将反义端粒酶序列导入肺腺癌细胞株A5 49及小细胞癌细胞株NCI H44 6中 ,采用MTT法检测活细胞数 ,采用RT PCR ELLISA法检测端粒酶活性。结果　转染 72h后 ,A5 49、NCI H 44 6细胞株端粒酶活性 (A45 0值 )分别由 0 .5 82± 0 .0 3 9和 0 .5 71± 0 .0 43降低至 0 .2 94± 0 .0 48(P <0 .0 1)和 0 .2 76± 0 .0 5 1(P <0 .0 1) ;而两细胞株的活细胞数 (A5 80值 )分别由 0 .485± 0 .0 0 9和 0 .5 13± 0 .0 15降低至 0 .191± 0 .0 2 7(P <0 .0 1)和 0 .13 8± 0 .0 46(P <0 .0 1) ,细胞生长受到显著抑制。结论　反义端粒酶PNA片段具有抑制肺癌细胞株端粒酶活性的作用 ,并可抑制肺癌细胞的生长     

Further isolation and characterization of grammistins from the skin secretion of the soapfish Grammistes sexlineatus.

Soapfishes contain peptide toxins (grammistins) in the skin secretion. Two grammistins (Gs 1 and Gs 2) and six grammistins (Pp 1, Pp 2a, Pp 2b, Pp 3, Pp 4a and Pp 4b) have already been isolated from Grammistes sexlineatus and Pogonoperca punctata, respectively. In this study, five grammistins (Gs A-E), together with grammistins Gs 1 and Gs 2, were further isolated from G. sexlineatus by gel filtration and reverse-phase HPLC. Sequence analyses revealed that grammistins Gs A (28 residues) and Gs C (26 residues) are analogous to grammistin Pp 3 and grammistin Gs B (12 residues) to grammistin Pp 1, while grammistins Gs D (13 residues) and Gs E (13 residues) are identical with grammistins Pp 1 and Pp 2b, respectively. Grammistins Gs A-C exhibited antibacterial activity with a broad spectrum against nine species of bacteria in common with the other grammistins but had no hemolytic activity differing from the other grammistins. Grammistins Gs A-E, Gs 1 and Gs 2 could release carboxyfluorescein entrapped within liposomes made of either phosphatidylcholine or phosphatidylglycerol/phosphatidylcholine (3:1), demonstrating their membrane-lytic activity. However, no clear relationship between the membrane-lytic activity and the biological activity of grammistins was recognized.     

Mechanisms governing the differentiation of a serotonergic phenotype in culture

The blood–brain barrier prevents the entry of many potentially therapeutic peptide drugs to the brain. Glycosylation has shown potential as a methodology for improving delivery to the CNS. Previous studies have shown improved bioavailability and improved centrally mediated analgesia of glycosylated opioids. In this study we investigate the effect of glycosylation on the cyclic opioid peptide [ -Cys^2,5,Ser⁶,Gly⁷] enkephalin. The peptide was glycosylated on the Ser⁶ via an O-linkage with various sugar moieties and alignments. The peptides were then investigated for receptor binding, physiochemical attributes, in situ brain uptake in female Sprague–Dawley rats and antinociception in male ICR mice. Glycosylation resulted in a slight decrease in affinity to the δ-opioid receptor, and mixed effect on binding to the μ-opioid receptor. There was a significant decrease in lipophilicity resulting from glycosylation and a slight reduction in binding to bovine serum albumin. In situ perfusion showed that brain uptake was improved by up to 98% for several of the glycosylated peptides, and the nociceptive profiles of the peptides, in general, followed the rank order of peptide entry to the brain with up to a 39-fold increase in A.U.C.     

鲨肝活性肽S-8300对小鼠急性肝损伤的保护作用

目的：研究鲨肝活性肽S-8300对四氯化碳(CCl4)小鼠肝损伤的保护作用。方法：采用CCl4致小鼠肝损伤，观察肝组织切片；测定生化指标，检测小鼠腹腔注射S-8300后血清谷丙转氨酶(sGPT)、血清谷草转氨酶(sGOT)和乳酸脱氢酶(LDH)活性，肝脏超氧化物歧化酶(SOD)活性与丙二醛(MDA)和谷胱甘肽(GSH)含量。结果：S-8300能明显减轻CCl4所致小鼠急性肝损伤；降低血清GPT、GOT、LDH活性及降低肝组织MDA含量，增加肝组织GSH含量和提高SOD活性。结论：鲨肝活性肽S-8300对急性肝损伤有明显的保护作用。     

C肽、血脂水平与2型糖尿病下肢血管病变的关系

目的探讨2型糖尿病患者下肢血管病变的危险因素。方法应用美国GE公司LOG-IQ700型超声诊断仪,对2型糖尿病患者131例下肢动脉进行检测,将下肢血管病变组74例与非下肢血管病变组54例进行对照,记录患者年龄、病程、空腹及餐后血糖、糖化血红蛋白、血脂、空腹及餐后C肽。结果糖尿病下肢血管病变组患者年龄大、病程长、LDL-C明显升高、空腹及餐后C肽明显降低。结论年龄、病程、高血糖、高血脂、低C肽水平是糖尿病下肢血管病变的危险因素,糖尿病神经病变与大血管病变正相关。     

Antimicrobial activity of myotoxic phospholipases A2 from crotalid snake venoms and synthetic peptide variants derived from their C-terminal region.

A short peptide derived from the C-terminal region of Bothrops asper myotoxin II, a Lys49 phospholipase A(2) (PLA(2)), was previously found to reproduce the bactericidal activity of its parent molecule. In this study, a panel of eight PLA(2) myotoxins purified from crotalid snake venoms, including both Lys49 and Asp49-type isoforms, were all found to express bactericidal activity, indicating that this may be a common action of the group IIA PLA(2) protein family. A series of 10 synthetic peptide variants, based on the original C-terminal sequence 115-129 of myotoxin II and its triple Tyr-->Trp substituted peptide p115-W3, were characterized. In vitro assays for bactericidal, cytolytic and anti-endotoxic activities of these peptides suggest a general correlation between the number of tryptophan substitutions introduced and microbicidal potency, both against Gram-negative (Salmonella typhimurium) and Gram-positive (Staphylococcus aureus) bacteria. Peptide variants with high bactericidal activity also tended to be more cytolytic towards skeletal muscle C2C12 myoblasts, thus limiting their potential in vivo use. However, the peptide variant pEM-2 (KKWRWWLKALAKK) showed reduced toxicity towards muscle cells, while retaining high bactericidal potency. This peptide also showed the highest endotoxin-neutralizing activity in vitro, and was shown to functionally interact with lipopolysaccharide (LPS) using a chimeric bacteria model. The bactericidal and anti-endotoxic properties of pEM-2, combined with its relatively low toxicity towards eukaryotic cells, highlight it as a promising candidate for further evaluation of its antimicrobial potential in vivo.     

Naja melanoleuca cobra venom contains two forms of complement-depleting factor (CVF)

Two forms of complement-depleting cobra venom factor (CVFm1 and CVFm2), possessing molecular masses of 142.6 kDa (CVFm1) and 143.1 kDa (CVFm2), according to MALDI mass-spectrometry, were isolated from the Naja melanoleuca cobra venom. As shown by polyacrylamide gel electrophoresis in the presence of SDS, both forms similarly to factor from the Naja kaouthia cobra venom (CVFk) consist of three polypeptide chains with molecular masses of about 70, 50, and 30 kDa, the two large subunits being glycosylated. As determined by MALDI mass-spectrometry, 30 kDa subunits of CVFm1 and CVFm2 have considerably different finger-prints of tryptic digests that suggests differences in their amino acid sequences. A study of activity in vivo has shown no significant differences in C3 consumption by CVFm1, CVFm2 and CVFk in mouse blood. However, as shown by an immunoassay method, they differ in their ability to activate the complement system via C3 conversion, the ratio of these activities for CVFm1:CVFm2:CVFk being 2.5:1.6:1. Kinetic studies using a hemolytic test showed that complement depletion by CVFm1 is faster than that by CVFm2. Thus, for the first time the presence in a single venom of two forms of CVF differing by both amino acid sequence and biological activity has been shown.     

Proteomics approach on microcystin binding proteins in mouse liver for investigation of microcystin toxicity.

Microcystins (MC) produced by freshwater cyanobacteria are potent hepatotoxins. MC inhibit protein phosphatases (PP) 1 and 2A. MC and okadaic acid (OA), which is a similar PP inhibitor whereas it has a less affinity to PP1 than PP2A, behave similarly to primary culture hepatocytes, with inducements of phosphorylations of cytoskeleton, morphological changes and apoptosis. Although the distribution of OA in mouse liver was observed immunohistochemically, no OA injury was found. The purpose of this study was therefore to determine why only MC has specific toxicities on the liver. A systematic process of MC affinity chromatography and proteomics, using two-dimensional gel electrophoresis and MALDI-TOFMS, indicated the existence of some MC-binding proteins including the complexes of PP1, PP2A, and PP4 with their own regulatory subunits in mouse liver extracts. The competitive inhibition experiments using affinity chromatography with OA showed that two of the three protein complexes strongly interacted with OA, whereas only the complex of PP1 with the inhibitory subunit NIPP1 did not strongly interacted with OA. These results suggest that the PP1 complex is not related to the common behavior of MC and OA of primary culture hepatocytes, and is related to the specific hepatotoxicities of MC.     

Rapid and efficient identification of cysteine-rich peptides by random screening of a venom gland cDNA library from the hexathelid spider Macrothele gigas.

We identified novel 10 multi-cysteine peptides, namely Magi 7-16, from the spider Macrothele gigas by simple random cDNA screening of the venom gland. Mass analysis of the crude venom detected the mass numbers of the cross-linked forms of all peptides, confirming their presence in the venom. Magi 11, a C-terminus amidated peptide, was chemically synthesized and was indistinguishable from the native peptide proving the feasibility of the method for peptide identification. Moreover, toxicological assays showed diverse lethal or paralytic activities of these peptide toxins on mice and/or insects.     

58例甲状腺髓样癌降钙素及其基因相关肽检测的临床意义

目的:探讨甲状腺髓样癌患者降钙素及其基因相关肽的变化规律以指导临床治疗方案的选择和患者预后的判断.方法:对58例甲状腺髓样癌患者血清中降钙素进行分析及应用免疫组织化学方法观察相应标本中降钙素及其基因相关肽的表达情况;对新入组患者进行放射免疫学测定.结果:1)术前降钙素水平正常与升高的患者之间,颈淋巴结转移存在显著性差异(P＜0.01).2)术后1个月降钙素水平正常与升高的患者之间,肿瘤复发存在显著性差异(P＜0.01).3)约98%的患者肿瘤标本降钙素染色呈阳性,而降钙素基因相关肽的阳性率为87.8%.4)部分术前降钙素水平正常的惠者降钙素基因相关肽水平升高.5)术后1周左右降钙素下降至一稳定水平.结论:降钙素可以作为指导甲状腺髓样癌诊断和治疗的重要指标,检测降钙素基因相关肽有助于部分降钙素阴性的甲状腺髓样癌患者术前诊断.