937 resultados para VAL
Resumo:
本发明涉及棕点湍蛙胰岛素释放促进肽和在制药中的应用,属于生物医学技术领域。本发明通过常规的生物化学手段,从棕点湍蛙皮肤分泌液中分离纯化得到胰岛素释放促进肽并测定其序列,按照所得的序列合成该多肽。棕点湍蛙胰岛素释放促进肽是一种单链多肽,分子量1627.04道尔顿,等电点8.75,多肽一级结构全序列为:Phe-Leu-Pro-Ile-Val-Gly-Lys-Leu-Leu-Ser-Gly-Leu-Ser-Gly-Leu- Leu(FLPIVGKLLSGLSGLL-NH2)。本发明具有很好的促进胰岛素释放的作用,同时还具有无溶血活性、无血浆凝固活性等优点,可作为制备治疗糖尿病药物的应用。
Resumo:
本发明涉及一种无指盘臭蛙蛙皮肽及其基因和在制药中的应用,属于生物医学领域。该活性多肽是中国两栖类动物无指盘臭蛙基因编码的一种单链多肽,分子量3355.95道尔顿,等电点10.14,多肽全序列一级结构为: Gly Leu Gly Gly Ala Lys Lys Asn Phe Ile Ile Ala Ala Asn Lys Thr Ala Pro Gln Ser Val Lys Lys Thr Phe Ser Cys Lys Leu Tyr Asn Gly。编码无指盘臭蛙蛙皮肽的基因由 731个核苷酸组成,其中编码成熟无指盘臭蛙蛙皮肽为第520-616位核苷酸。人工合成的无指盘臭蛙蛙皮肽具有显著的抑制细菌和真菌生长的作用,可以作为制备病原微生物感染疾病的治疗药物被应用。本发明的无指盘臭蛙蛙皮肽具有结构简单、人工合成方便、抗菌谱系广的有益特点。
Resumo:
本发明涉及无指盘臭蛙免疫调节肽、基因和变异体及其在制药中的应用,属生物医学技术领域。无指盘臭蛙免疫调节肽是一种环状多肽,分子量1791.12道尔顿,等电点 9.84,无指盘臭蛙免疫调节肽的全序列为:Thr Ser Arg Cys Tyr Ile Gly Tyr Arg Arg Lys Val Val Cys Ser(TSRCYIGYRRKVVCS),其第4位的半胱氨酸和第14位的半胱氨酸形成分子内二硫键。编码的基因由307个核苷酸组成,其中编码成熟部分的为第 141-186位核苷酸。无指盘臭蛙免疫调节肽原始序列中第4个氨基酸发生替代所产生的变异体,人工合成的无指盘臭蛙免疫调节肽及其变异体具有强烈的免疫调节活性和肿瘤抑制活性,作为制备免疫调节、肿瘤治疗和化疗药物的应用。本发明还具有序列简单、合成方便等优点。
Resumo:
本发明涉及一种无指盘臭蛙抗微生物多肽及其基因和在制药上的应用,属于生物医学领域。无指盘臭蛙抗微生物多肽是无指盘臭蛙抗微生物多肽基因编码的一种单链多肽,分子量为4248.27道尔顿,等电点为11.47,多肽全序列一级结构为:Gly Leu Phe Thr Leu Ile Lys Gly Ala Ala Lys Leu Ile Gly Lys Thr Val Pro Lys Lys Gln Ala Arg Leu Gly Met Asn Leu Trp Leu Val Lys Leu Pro Thr Asn Val Lys Thr (GLFTLIKGAAKLIGKTVPKKQARLGMNLWLVKLPTNVKT)。编码无指盘臭蛙抗微生物多肽的基因由343个核苷酸组成,其中编码成熟无指盘臭蛙抗微生物多肽为第123-240位核苷酸。人工合成的无指盘臭蛙抗微生物多肽具有很强的抑制细菌和真菌生长的作用,可以作为制备病原微生物感染疾病的治疗药物被应用。本发明的无指盘臭蛙抗微生物多肽具有抗菌谱系广、抗菌活性强的特点。
Resumo:
Jerdonobin and jerdofibrase are two serine proteases purified from the venom of Trimeresurus jerdonii. The Michaelis constant K-m and the catalytic rate constant K-cat of jerdonobin or jerdofibrase on three chromogenic substrates, H-D-Pro-Phe-Arg-pNA (S2302), H-D-Phe-pipecolyl-Arg-pNA (S2238), and H-D-Val-Leu-Lys-pNA (S2251) were obtained from lineweaver-Burk plots. Jerdofibrase could hydrolyze all three substrates, but jerdonobin had no detectable activity on S2251, suggesting a relatively broader substrate specificity for jerdofibrase than jerdonobin. By SDS-PAGE, jerdofibrase preferentially degraded Bbeta-chain of fibrinogen. It also degraded Aalpha-chain of fibrinogen with relatively slow activity, but did not act on the gamma-chain. In contrast, jerdonobin did not degrade fibrinogen within 12 h. Fibrinopeptides liberation test, identified by HPLC, showed jerdonobin released fibrinopeptide A and a small amount of fibrinopeptide B. Unlike jerdonobin, jerdofibrase mainly released fibrinopeptide B. These results indicate that the two enzymes differ in their ability to hydrolyze chromogenic substrates and in their actions on fibrinogen. (C) 2002 Elsevier Science Inc. All rights reserved.
Resumo:
Siganus lineatus (Cuv. and Val) is reported from the coast of peninsular India for the first time and a detailed description of it is given based on morphology and meristic characters. It differs from the other allied species of the genus Siganus Forskal in having an oval body without spots and having fifteen parallel longitudinal golden yellow bands, relatively larger last dorsal spine, maxillary position far below the level of the orbit and cheek with distinct rows of scales. S. javus (Linnaeus) and S. canaliculatus (Park) were also obtained from the Vembanad Lake. Short notes on the habitat, occurrence, abundance, seasonal and geographic distribution in relation to fluctuating hydrological conditions of the Vembanad Lake are incorporated together with a key for their identification.
Resumo:
Ranid frogs of the genus Amolops occur in Southeast Asia and are typically found near waterfalls. Their phylogenetic relationships have not been resolved. We include 2,213 aligned nucleotide sites of the 12S, 16S and tRNA(val) gene regions of the mitochondrial DNA genome from 43 individuals of Chinese and Vietnamese Amotops, Huia, Hylarana, Meristogenys, Odorrana and Rana. The outgroup species were from the genera Chaparana, Limnonectes, Nanorana, and Paa. The data were analyzed within the framework of a refutationist philosophy using maximum parsimony. Four clades of waterfall frogs were resolved. Meristogenys was not resolved as the sister group to either Huia nor Amolops. The hypothesis Of evolutionary relationships placed Amolops chapaensis and Huia nasica in the genus Odorrana.
Resumo:
应用高效液相色谱(HPLC)技术,首次测定了湖北石首长江天鹅州白豚自然保护区野生长江江豚(Neopho-caena phocaenoides asiaeorientalis)和中国科学院水生生物研究所白豚馆人工饲养的长江江豚血清中17种氨基酸的含量。结果表明,除了脯氨酸Pro、蛋氨酸Met和组氨酸His外,人工饲养江豚血清中其余14种氨基酸(天门冬氨酸Asp、谷氨酸Glu、丝氨酸Ser、精氨酸Arg、甘氨酸Gly、苏氨酸Thr、丙氨酸Ala、异亮氨酸Ile、亮氨酸Leu、苯丙氨酸Phe、缬氨酸Val、赖氨
Resumo:
<正> 斑点气单胞菌(Aeromonas punctata)是危害草鱼(Ctenopharyngodon idellus Cuv. et val.)的主要病原菌之一同时也危害鲢、鳙等多种鱼类。但作为一种病原菌对鱼类的毒力有多大,乞今还没有可靠的报道。
Resumo:
<正> 1973年4月20日和1976年6月8日,我们先后在河北省怀来县官厅水库和安徽省繁昌县龙窝湖采集的白鲢 Hypophthalmichthys molitrix(Cuvier et Val eaciennes)以及细鳞斜颌鲴 Plagiognathops microlepis(Bleeker)中发现两种粘孢子虫,经研究鉴定为粘袍子虫一新属二新种。 模式标本均保存在中国科学院水生生物研究所。
Resumo:
<正> 鲮鱼[Cirrhina molitorella(Cur.&Val.)]是广东地区饲养的家鱼之一,群众有一套用“大草”养它的经验,但在饲育过程中,鱼苗往往发生一种流行病,导致大量死亡。患病的鱼苗,身体瘦弱,体色发黑,游动缓慢,常浮游在靠近池边的水面上,不久即翻身死亡。情况严重时全池鱼苗能全部死完。但过去并没有引起水产科学工作者的注意。为了提高角苗的成活率和鱼苗的体质,给培育鱼种和饲养成鱼打下更好的基础,对鲮角鱼苗病的研
Resumo:
Natural killer (NK) cell enhancing factor (NKEF) belongs to the newly defined peroxiredoxin (Prx) family. Its functions are to enhance NK cell cytotoxicity and to protect DNA and proteins from oxidative damage. In this study, a partial cDNA sequence of carp NKEF-B was isolated from thymus cDNA library. Subsequently, the full-length cDNA of carp NKEF-B was obtained by means of 3' and 5' RACE, respectively. The full-length cDNA of carp NKEF-B was 1022 bp, consisting of a 73 bp 5'-terminal untranslated region (UTR), a 355 bp T-terminal UTR, and a 594 bp open reading frame coding for a protein of 197 amino acids. Carp NKEF-B contained two consensus Val-Cys-Pro (VCP) motifs and three consensus cysteine (Cys-51, Cys-70 and Cys-172) residues. Sequence comparison showed that the deduced amino acid sequence of carp NKEF-B had an overall similarity of 74-96% to that of other species homologues. Phylogenetic analysis revealed that carp NKEF-B forms a cluster with other known teleost NKEF-Bs. Then, by PCR we obtained a 5.1 -k long genomic DNA of carp NKEF-B containing six exons and five introns. Realtime RT-PCR results showed that carp NKEF-B gene was predominantly detected in kidney and head kidney under un-infected conditions. Whereas under SVCV-infection condition, the expression of NKEF-B gene was significantly increased in blood cells, gill, intestine and spleen, but maintained in liver, and decreased significantly in kidney and head kidney. Finally, the rNKEF-B was constructed and expressed in Escherichia coli. By using an antibody against carp rNKEF-B, immunohistochemical study further indicated that NKEF-B positive cells are mainly some RBCs and a few epithelial cells in gill and intestine, and that under SVCV-infection condition, these positive cells or positive products in their cytoplasm were mainly increased in gill and spleen sections of carp. The results obtained in the present study will help to understand the function of NKEF-B in teleost innate immunity. (C) 2008 Elsevier Ltd. All rights reserved.
Resumo:
土壤胀缩是土壤在干燥、湿润交替变化过程中所表现出的土壤容积随含水量改变的现象。本文通过测定4种土壤脱水和吸水过程中的土柱高度和直径的变化,分析了胀缩过程中土壤容积与含水量的关系及土壤的胀缩特征。结果显示:三直线模型能够很好地拟合4种土壤的收缩、膨胀过程;土壤收缩、膨胀曲线各段的特征值均小于1,这说明土壤胀缩过程中土壤容积的变化速率小于含水量的变化速率;4种土壤胀缩过程中几何因子rs大于1而小于3,且收缩初期几何因子rs等于1,表明土壤的胀缩是各向异性的,并且在土壤收缩的最初阶段只有垂直收缩。
Resumo:
DNA是重要的生物大分子,也是主要的抗癌药物靶分子。小分子与DNA之间的相互作用是以DNA为靶分子的各种物质生物效应的基础,它们之间的特异性结合导致了癌变、突变及细胞的死亡。能够与DNA特异性结合的小分子很多都是临床上广泛应用的抗癌药物。因此,小分子与DNA之间的相互作用不论是对阐述抗癌、抗病毒药物的作用,还是对致癌机理的研究,尤其对抗癌药物的体内筛选都有重要意义。近十年来,开发新型的抗癌药物小分子,使它们具有对DNA序列特异性的识别能力己成为国内外研究的热点。斓系配合物由于具有广泛的光学、磁学和电学等特性使得有可能成为新的DNA特异性识别分子。然而,斓系离子在中性条件下极其容易水解的特性又极大的阻碍了斓系配合物对于DNA的识别性研究。本文在中性条件下合成了铜系氨基酸配合物,并成功的获得了这些配合物的晶体结构,利用这些有确定结构的I系氨基酸配合物与特定的DNA序列相作用,通过多种生物物理方法研究了它们对DNA序列特异性识别。主要的结果如下:1.在近中性条件下,合成了Eu-Val([Eus_8(L-HVal)_(16)(H_2O)_(32)]Cl_(24)·12.5H_2O),Eu-Asp([Eu_4(μ3-OH)_4(L-Asp)_2(L-HAsp)_3(H_2O)_7]Cl·11.5H_2O)和Tb-Cys(「Th_2(DL-Cys)_4(H_2O)_8]Cl_2)三种铜系氨基酸配合物,这些配合物的结构由于合成条件(温度,反离子及合成比例)上的差异与已报到的类似配合物的结构具有明显的不同。三种配合物的结构各具特色,从而在与DNA作用时将表现出各自特有的识别性能。2.Eu-Val配合物在与单链DNA作用时,配合物能键合到DNA碱基所在的疏水区,在与富含dC和dT碱基的序列相结合时,发生显著的能量传递,从而极大的增强了配合物中Eu的发射光谱。配合物结合DNA的化学计量比随序列中dC含量的降低而降低。配合物同样能够与处于DNA疏水区的富含dA和dG序列相结合,这种结合不能够产生能量传递,但使得DNA的紫外-可见光谱出现明显的减色和红移现象。此外,这一配合物还能够诱导单链DNApoly(dA)及p01y(rA)产生自身的二级结构,形成双链结构。这为进一步认识斓系离子的生物学效应奠定了基础,斓系氨基酸配合物可以诱导单链poly(dA)及poly(rA)形成自身结构尚无文献报道。3.Eu一AsP配合物能够选择性的稳定非B一构象的Poly(dA)Poly(dT),而使B一构象的印oly(dAdT)]2和[Poly(dGdC)]2变得不稳定。如在1:2比例时,该配合物可使Poly(dA)Polv(dT)的融化温度提高4℃,而使印oly(dAdT)}2的融化温度降低6℃,[Poly(dGdC)]2则出现了两个转变温度。进一步的圆二色实验结果充分表明Eu一Asp配合物对于富含Poly(dA)Poly(dT)和[Poly(dAdT)]2的双链DNA没有构象上的改变,而对于[Poly(dGdC)]2的双链DNA则产生了显著的构象上的改变,很有可能正是这一改变使得[Poly(dGdC)]2变得极其的不稳定。配合物对[Poly(dGdC)]2的这种不稳定影响随着配合物浓度的逐步升高而越来越明显。变温实验结果清楚的表明,在37℃时,Eu-AsP使[Poly(dGdC)JZ发生了构象转化,并且这种转化是可逆的。4.Tb-Cys配合物与单链(除了poly(dA))和双链DNA都能发生能量传递,从而使得配合物的荧光显著增强。不同的DNA表现出不同的增强效果,表明TbCys配合物对DNA的序列存在选择性,单链要强于双链,富含Poly(dAdG)的序列增强效果最好。单链和双链能量传递的差异表明了配合物能够区分DNA的单链和双链,配合物在与单链作用时结合更强。TbCys配合物在与DNA作用时存在不同的结合位点,而且单链和双链的结合位点明显不同。TbCys配合物能够引起富含dC和dT的单链DNA发生减色效应,而能够引起富含poly(dA)、poly(dAdG)的单链DNA和富含poly(dA)poly(dT)、[Poly(dAdT)]2和[poly(dGdC)]2的双链DNA发生明显的红移。此外,这一配合物同样能够影响双链DNA的稳定性,使得富含poly(dA)Poly(dT)序列变得稳定,而使得富含印oly(dAdT)]2和富含印oly(dGdC)]2的序列变得不稳定。这些结果都表明了配合物对DNA存在选择性。比较不同配合物的差别后能够发现DNA对于不同的配合物同样具有选II择性,这种选择性能够用来区分配合物。一这些钢系氨基酸配合物由于选择了天然的氨基酸作为配体,从而大大的降低了对人体的毒性,进一步表现出的对不同的DNA序列的选择型则使其有望成为新型的抗癌诊疗试剂。