新型基因重组PACAP衍生物MPL-2的制备及其抗2型糖尿病作用研究

利用基因工程技术高效制备具有治疗2型糖尿病功能的垂体腺苷酸环化酶激活肽(PACAP)衍生物MPL-2,并以2型糖尿病小鼠(db/db小鼠)为模型在体内研究其抗2型糖尿病的生物学作用。实验结果表明:利用基因工程技术制备的PACAP27衍生多肽MPL-2的分子质量为3 902Da.,纯度达97%,其产率可达29.3mg/L发酵产物;在以db/db小鼠为模型的体内葡萄糖耐量实验中,MPL-2可有效促进小鼠胰岛素第一时相(5~15min)分泌,显著提高小鼠的葡萄糖耐受能力。在MPL-2的长效药效学实验中,经过8周连续用药治疗后,MPL-2可显著提高db/db小鼠的胰岛素敏感性,胰岛素耐量实验60min时MPL-2可将小鼠血糖降至初始值的63.52%;同时,在8周连续用药治疗过程中,与生理盐水(NS)处理组相比,MPL-2可有效降低db/db小鼠的体重、空腹血糖、饮食量、饮水量,分别低于NS组21.98%、21.46%、22.20%、60.07%,而且可显著改善db/db小鼠的血脂常数,生物学作用显著优于多肽BAY55-9837。建立了新型基因重组PACAP27衍生多肽MPL-2的高效制备技术,重组多肽MPL-2可有效改善2型糖尿病db/db小鼠的葡萄糖耐量、胰岛素敏感性、血脂常数,显著降低db/db小鼠的体重、空腹血糖、饮食和饮水量,从而发挥治疗2型糖尿病的生物学作用,可为MPL-2的药用研发提供实验数据。     

PACAP27对Ⅱ型糖尿病诱导的睾丸损伤的保护作用

目的 研究垂体腺苷酸环化酶激活肽(pituitary adenylate cyclase-activating polypeptide,PACAP)对Ⅱ型糖尿病大鼠睾丸损伤的保护作用.方法 18只雄性SD大鼠随机平均分为对照组、Ⅱ型糖尿病组和Ⅱ型糖尿病PACAP27干预组3组.腹腔注射链脲霉素和60％高脂饲料喂食,建立...     

海参肽对db/db小鼠降糖作用和炎症反应程度的影响

目的：观察海参肽对2型糖尿病模型小鼠的降糖作用和炎症反应程度的影响作用,为海参肽在糖尿病降糖作用以及抗炎作用提供科学依据。方法：本研究拟以海参肽为干预物,以db/db小鼠为模型动物开展研究。选用空腹血糖水平≥11.1mmol/L的db/db小鼠,适应饲养1w后,以不同浓度的海参肽连续灌胃45d,期间观察其毛色、活动情况以及饮水排尿量,并于实验前、中、后期测定空腹血糖,实验前后期进行口服葡萄糖耐量实验,实验后采血测定相关血液生化指标,通过组间比较以判定海参肽的作用。结果：和模型对照组相比,海参肽中、高剂量组均能不同程度地改善2型糖尿病小鼠的体征状况,减轻多饮、多食、多尿的“三多”症状,提高2型糖尿病小鼠的生活质量。干预期间的同组横向对比中,中、高剂量海参肽干预组能够明显地降低db/db小鼠的空腹血糖（P＜0.05）,干预2、4、6w后,血糖值分别由13.62±1.64mmol/L降至11.59±3.26mmol/L,由14.82±3.09mmol/L降至12.36±3.28mmol/L;口服葡萄糖耐量实验中,在干预6w后,中、高剂量海参肽能有效降低db/db小鼠给予葡萄糖前后各时间点的血糖值和血糖—时间曲线下面积（P＜0.05）。在炎症抑制方面,与模型对照组相比,海参肽中、高剂量组能够显著降低IL-6、IL-8在小鼠体内的含量（P＜0.05）,提高IL-10在小鼠体内的表达（P＜0.05）,同时海参肽中、高剂量组能够降低TGF-α、MCP-1在小鼠体内的表达,从而具有一定的抗癌作用。结论：海参肽能够有效改善db/db小鼠的血糖调节能力以及口服糖耐量调节能力,同时发现海参肽可以有效抑制db/db小鼠体内炎症反应水平,一定程度上为海参肽于2型糖尿病防治及2型糖尿病并发炎症领域的应用及合理开发提供了新的思路和理论基础。     

核桃低聚肽对db/db小鼠血糖的影响作用研究

目的：研究核桃低聚肽（walnut oligopeptides,WOPs）干预对db/db糖尿病模型小鼠血糖的影响作用。方法：选择db/db糖尿病小鼠模型,将其随机分为3个核桃低聚肽组（220、440、880mg/kg·BW）、糖尿病模型对照组、二甲双胍对照组、乳清蛋白对照组;并选用db/m小鼠作为非糖尿病小鼠空白对照。经过为期6周的干预,检测小鼠空腹血糖、餐后血糖以及糖耐量实验血糖曲线下面积。结果：核桃低聚肽（880mg/kg·BW）可降低db/db糖尿病小鼠空腹血糖水平和餐后血糖水平,同时能有效改善糖耐量（P＜0.05）。结论：核桃低聚肽干预可有效降低糖尿病小鼠的血糖水平,改善糖耐量,具有辅助降血糖功能。     

人参低聚肽改善老龄db/db小鼠疾病状态和延长寿命的研究

目的：评价人参低聚肽（GOP）改善老龄db/db小鼠血糖水平和延长寿命的效果。 方法：采用db/db小鼠作为2型糖尿病模型。对老龄db/db（生长至70周龄）小鼠摄食量、体重、饮水量和尿量以及血糖水平进行测定,并且对老龄db/db小鼠存活率进行评价,表征GOP对疾病状态和寿命的改善效果。结果：GOP可以降低小鼠体重、摄食量、饮水量和尿量,改善老龄db/db小鼠的生存状态,同时,相比于模型对照组,GOP可以显著减少老龄db/db小鼠肾周脂肪指数和睾周脂肪指数（P<0.05）。通过GOP干预,可以降低老龄db/db小鼠的血糖水平,GOP干预组AUC为20mmol/（L·h）,显著低于模型对照组小鼠AUC［50 mmol/（L·h）］。当db/db小鼠增长至80周龄时,GOP干预组小鼠存活率为50%,大于模型对照组存活率（20%）。结论：GOP干预小鼠生存质量较高,并且寿命较长,说明GOP可以在一定程度上改善老龄db/db小鼠血糖情况,延长其寿命。本研究为利用GOP开展糖尿病的营养治疗提供了科学依据。     

海参胶原低聚肽对糖尿病小鼠术后伤口愈合的促进作用

目的：观察海参胶原低聚肽是否具有促进db/db 2型糖尿病小鼠术后伤口愈合的作用。 方法：取90只10w龄的db/db小鼠分为5组,包括模型对照组乳清蛋白组和3个海参胶原肽组（从低到高分别为0.25、0.50、1.00 g/kg·BW）,每组18只。另设一组同周龄、性别的db/m小鼠18只作为正常对照组。模型对照组和正常对照组使用溶剂（蒸馏水）灌胃。进行背部切口手术后开始干预,分别于术后第4、7、14d分批处死动物,每组每次处死6只。术后观察不同时期伤口愈合情况,测定血清生化指标、皮肤切口抗张力强度以及进行皮肤组织HE染色。结果：与模型对照组相比,海参胶原肽剂量组小鼠血清IL-8水平降低,IL-10水平升高,NO水平升高,伤口抗张力强度提升,伤口愈合较好。结论：海参胶原低聚肽能够改善糖尿病小鼠术后营养状况,促进伤口愈合。     

垂体腺苷酸环化酶激活肽减轻大鼠缺血性脑水肿作用的实验研究

目的研究垂体腺苷酸环化酶激活肽(PACAP)在缺血性脑水肿中的作用及其可能的受体机制.方法采用大鼠四动脉结扎脑缺血模型,分别运用干湿重法和酶学法测定脑组织含水量及Na+、K+含量.结果大鼠四动脉结扎脑缺血30in,再灌流1 h,脑组织含水量明显增加,a+含量增高,而K+含量降低.缺血前经测脑室分别给予1×10-9 mol、1×1110mol及1×11-11 mol的PACAP均能抑制脑组织含水量、Na+含量的增加和K+含量的降低.特异性PACAPⅠ型受体拮抗剂PACAP6-38能完全阻断PACAP的上述作用,而单纯给予PACAP6-38对脑缺血后脑组织含水量、Na+、K+含量无显著影响.结论外源性PACAP对缺血性脑水肿具有保护作用,该作用是由I型受体介导的.     

基因重组PACAP 27衍生多肽RP2制备及促角膜上皮细胞增殖研究

利用基因工程技术高效制备具有促进角膜上皮细胞增殖功能的垂体腺苷酸环化酶激活肽(PACAP 27)衍生多肽RP2,在细胞水平初步研究其生物学作用,为其用于角膜损伤治疗提供实验基础。采用基因重组技术表达重组肽RP2,经Chitin-Beads和HPLC纯化、SDS-PAGE和质谱鉴定后,研究其对小鼠角膜上皮细胞增殖的影响。实验结果表明:利用基因重组技术制备的PACAP 27衍生多肽RP2的分子量为3.3 k Da,纯度达96%;分别用重组肽RP2、PACAP 27及PBS作用于小鼠角膜上皮细胞,处理24 h及48 h时,RP2处理组角膜上皮细胞增殖率分别为(49.6±3.1)%、(93.0±1.7)%,PACAP 27处理组细胞增殖率分别为(29.0±2.4)%、(78.8±2.6)%,PBS对照组细胞增殖率为(20.2±1.1)%,(40.9±3.3)%。利用建立的重组多肽制备技术条件,可实现PACAP衍生多肽RP2高效制备,制备的RP2可有效促进角膜上皮细胞的增殖,从而有望成为一种新型角膜损伤治疗候选药物。     

PACAP及其衍生物治疗糖尿病及其并发症的研究进展

垂体腺苷酸环化酶激活肽(PACAP)是近年新发现的神经多肽,属于促胰液素/胰高血糖素/血管活性肽(VIP)家族中的新成员,广泛分布于脑和外周组织器官,尤其在内分泌胰腺、性腺、呼吸和生殖系统,在能量代谢、神经保护、免疫系统等发挥重要生理学功能。糖尿病是一种常见的主要以高血糖为特征的慢性代谢性疾病,糖尿病并发症日益严重威胁着人们的身体健康,已成为导致糖尿病患者致死、致残的主要原因。主要对PACAP治疗糖尿病及其并发症国内外研究的最新进展进行论述。     

纳米硒抗胰岛β细胞凋亡作用与机制的研究

旨在研究纳米硒(Se NPs)抗二型糖尿病胰岛β细胞凋亡的作用及机制。通过电子显微镜,纳米粒度仪等技术方法对Se NPs的表征进行鉴定,并运用相关分子生物学技术验证其对于胰岛β细胞凋亡模型的保护作用及机制。结果表明,壳聚糖(CS)修饰后的Se NPs表面电荷增加到24.8 mv,其保存期延长到100 d以上。另外,细胞学实验表明浓度在2μmol/L以下Se NPs不具有毒性,38.1 nmol/L Se NPs可通过激活硫氧还蛋白还原酶(Trx R)活性,从而减轻胞内氧化应激(ROS)水平,最终使胰岛β凋亡模型细胞存活率提高了31.75%。动物学实验也表明Se NPs能抗胰岛β细胞凋亡。因此,Se NPs可有效减轻二型糖尿病中胰岛β细胞凋亡,对于二型糖尿病具有潜在的治疗价值。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细