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1.
动物贮食行为及其生态意义   总被引:9,自引:0,他引:9  
动物贮存食物,以调节食物的时空分布,度过食物缺乏期。贮食行为是一种特化的采食行为。现已发现上百种鸟类和哺乳类动物贮存食物。植食动物贮藏植物繁殖体,促进了植物的扩散。于是,植物与贮食动物形成了一种协同进化关系。这种关系是自然界互惠关系(mutualism)的一种类型。  相似文献   

2.
基于最近邻居算法,从蛋白质一级序列出发,利用蛋白质序列氨基酸组成、二肤组成以及混合组成方法对蛋白质单聚体、二聚体、三聚体、四聚体、五聚体、六聚体和八聚体进行分类研究。结果表明:采用二肽组成编码方法的预洲效果最好,Jackknife检验和独立测试集检验的总体预测精度分别达到90.83%和95.48%,比相同数据集上基于伪氨基酸组成和组分耦合预测的方法提高了12和15个百分点;特别是对于五聚体蛋白,预测精度分别提高了90和50个百分点;说明二肽组成对于蛋白质四级结构分类研究是一种非常有效的特征提取方法。  相似文献   

3.
SDS-PAG电泳分析表明粘虫核型多角体病毒的包涵体蛋白由几种多肽组成,其中分子量为32kD的主带为多角体的主要结构多钛,经Sephaceyl S-20柱层析纯化后分析了其氨基酸组成,证明此包涵全蛋白是一种疏水氨基酸为主要组成的特异性蛋白。我们发现32kD蛋白对Hela,HLAMP、HICAM等三种肿瘤细胞的生长有不同程序的抑制,用^3H-TdR标记核酸合成代谢的Hela细胞的放射活性证实了这种观  相似文献   

4.
单链尿激酶型纤溶酶原激活物的结构和性质   总被引:2,自引:0,他引:2  
单链尿激酸型纤溶酶原激活物(scuPA)是一种丝氨酸蛋白酶,由411个氨基酸组成单一多肽链结构,是尿激酶的前体形式。它可特异地激活血栓局部的纤溶酶而启动纤溶系统,并与组织型纤溶酶原激活物(tPA)有协同作用,是一种有广泛前途的溶栓物质。  相似文献   

5.
SDS-PAG电泳分析表明粘虫核型多角体病毒(Leucaia separata Nuclear Polyhedrosis Virus,简称LsNPV)的包涵体蛋白由几种多肽组成,其中分子量为32kD的主带为多角体的主要结构多肽。经Sephaceyl S-200柱层析纯化后分析了其氨基酸组成,证明此包涵体蛋白是一种以疏水氨基酸为主要组成的特异性蛋白。我们发现32kD蛋白对Hela、HLAMP、HICAM等三种肿瘤细胞的生长有不同程度的抑制,用~3H-TdR标记核酸合成代谢的Hela细胞的放射活性证实了这种观察。  相似文献   

6.
神经介素S(neuromedin S,NMS)是一种由36个氨基酸组成的新的神经肽。Takanori Ida等在2005年Endocrinology上报道在大鼠脑中发现NMS,主要在视交叉神经核上表达,是G蛋白偶联受体FM-3/GPR66和FM-4/TGR—l的配体,这些受体分别是神经介素U(neuromedin U,NMU)1型和2型。他们研究发现NMS是一种新的食欲调节肽。给大鼠侧脑室内注射NMS后,NMS可以剂量依赖性地降低大鼠夜间12小时的食物和水的摄入量.其摄含抑制作用较相同剂量的NMU的抑制作用强,持续时间久,  相似文献   

7.
NPCEDRG基因是采用基因定位候选克隆策略获得的1个鼻咽癌候选抑瘤基因. NPCEDRG在鼻咽癌细胞和组织中表达下调,重新恢复NPCEDRG基因在CNE2细胞系的表达,可部分逆转CNE2 的恶性表型. 本研究对CNE2细胞所表达的NPCEDRG基因mRNA剪接变异体克隆、鉴定,发现NPCEDRG基因至少有7个转录起始位点,其中NM_032316的TSS位于ATG上游-85 nt处,AF538150和AK094248的TSS位于-25 nt处;AF538150不存在第2外显子中6核苷酸序列(5′-TTGCAG-3′)的缺失,其CDs为516 bp,编码1种由171个氨基酸组成的蛋白质(而非GenBank中公布的CDs为510 bp,1种由169个氨基酸组成的蛋白质). 本研究成功克隆得到1种新的NPCEDRG基因的mRNA剪接变异体V2,其TSS位于-23 nt处,其CDs为297 bp,编码1种由98个氨基酸组成的蛋白质.  相似文献   

8.
洗胃法在鳄蜥食性研究中的应用   总被引:1,自引:0,他引:1  
为了研究洗胃法是否适用于鳄蜥(Shinisaurus crocodilurus)的食性研究,2006年8~9月我们在广东罗坑省级自然保护区,通过投喂食物,然后再冲洗的方法来检验洗胃法的冲洗效果。结果显示洗胃法对成体和亚成体鳄蜥的总洗出率均高于99.30%,食物个体数的洗出率均高于90.83%,投喂的12种食物都能被洗出。观察发现洗胃之后,对鳄蜥的正常生活没有影响。鳄蜥吃进的实验食物中,未洗出的食物大小与鳄蜥的体长、头宽、体重不相关;食物的洗出效率与鳄蜥的体长、头宽、体重不相关。成体、亚成体洗出和未洗出的食物大小均存在显著差异。未被洗出的食物个体在12种食物中不是随机分布的,体积大的食物比体积小的食物容易被洗出。研究表明,洗胃法适用于鳄蜥的食性研究,并且效果较好。  相似文献   

9.
重组人肝细胞生成素的纯化及活性研究   总被引:1,自引:0,他引:1  
人肝细胞生成素 ( human hepatopoietin,h HPO)是一种新型肝再生调控因子 .在大肠杆菌中表达的的重组 h HPO( rh HPO)是以包涵体的形式存在的 ,其表达量为菌体总蛋白的 2 0 % .包涵体经各种溶液洗涤后 ,用 8mol/L尿素裂解 ,裂解上清经凝胶过滤、复性和离子交换柱层析得到电泳纯的 rh HPO,经还原型 SDS- PAGE测定其分子量为 1 5k D.纯化 rh HPO的 N端氨基酸序列与其c DNA推导序列完全一致 ;纯化产物的氨基酸组成分析结果亦与 rh HPO氨基酸组成的理论值吻合 .生物学活性研究表明 ,rh HPO在体外具有刺激原代培养肝细胞增殖作用  相似文献   

10.
通过将包括猪胰岛素前体(PIP)基因在内的表达框架克隆至质粒pKD1衍生的两种载体上而在酵母Kluyveromyceslactis中分泌表达猪胰岛素前体。根据放射免疫测定结果,猪胰岛素前体的表达水平为20~30mg/L。猪胰岛素前体经过转肽被转变为基因工程人胰岛素。分析结果表明,来自K.lactis的人胰岛素,其氨基酸组成、晶体形状和生物活力与天然胰岛素相同。  相似文献   

11.
《Journal of Asia》2022,25(1):101873
Bee bread is prepared from pollen sources and salivary secretions by honey bee workers to serves the nutritional purpose of colony members. However, changes in nutrient composition occurring in bee bread from the pollen sources including pollen patty are poorly understood. We, therefore, examined the nutrient contents of pollen patty, used as source pollen feed of honey bee colony, and bee bread prepared by honey bee from this source at different time interval. Results revealed that amino acid content was increased from pollen patty to bee bread but fatty acid content was decreased. Essential amino acids like valine, lysine, and nonessential amino acids such as proline and alanine increased significantly over time. Among fatty acids, oleic acid, linoleic acid and linolenic acid decreased significantly from pollen patty to bee bread. Minerals contents in bee bread did not show any significant change during the study period. These changes could be presumably justified due to addition of nectar, honey, gland secretions and also microbial symbionts which remains as a task of further study.  相似文献   

12.
《Journal of Asia》2014,17(4):695-700
Bee venom contains a variety of peptides and enzymes, including acid phosphatases. An acid phosphatase has been identified from European honeybee (Apis mellifera) venom. However, although the amino acid sequence is known, no functional information is currently available for bee venom acid phosphatase Acph-1-like proteins. In this study, an Asiatic honeybee (Apis cerana) venom acid phosphatase Acph-1-like protein (AcAcph-1) was identified. The analysis of the predicted AcAcph-1 amino acid sequence revealed high levels of identity with other bee venom acid phosphatase Acph-1-like proteins. Recombinant AcAcph-1 was expressed as a 64-kDa protein in baculovirus-infected insect cells. The enzymatic properties of recombinant AcAcph-1, determined using p-nitrophenyl phosphate (p-NPP) as a substrate, showed the highest activity at 45 °C and pH 4.8. Northern and western blot analyses showed that AcAcph-1 was expressed in the venom gland and was present as a 64-kDa protein in bee venom. In addition, N-glycosylation of AcAcph-1 was revealed by tunicamycin treatment of recombinant virus-infected insect Sf9 cells and by glycoprotein staining of purified recombinant AcAcph-1. Our findings show that AcAcph-1 functions as a venom acid phosphatase. This paper provides the first evidence of the role of a bee venom acid phosphatase Acph-1-like protein.  相似文献   

13.
Purification and characterization of honey bee vitellogenin   总被引:4,自引:0,他引:4  
A protocol has been developed for the purification of vitellogenin from the honey bee, Apis mellifera. Purification allows for the first characterization of a vitellogenin from the large order Hymenoptera. Hymenopteran vitellogenins are unusual among insect vitellogenins in that they contain only one type of apoprotein. The honey bee vitellogenin was isolated from hemolymph of honey bee queens by a combination of density gradient ultracentrifugation, ion-exchange chromatography, and affinity chromatography. The native vitellogenin particle is a very high density glycolipoprotein containing approximately 91% protein, 7% lipid, and 2% carbohydrate. Phospholipid and diacylglycerol are the major lipid components. The equilibrium density (1.28 g/ml) is the same as that for Manduca sexta vitellogenin, which contains a much higher proportion of lipid. The covalently bound carbohydrate moiety of the particle is high in mannose. The amino acid composition of vitellogenin is similar to those of vitellogenins from other insect species. The N-terminal amino acid sequence of the apoprotein was determined, the first such sequence for any insect vitellogenin. When analyzed by sodium dodecyl sulfate (SDS)-gel electrophoresis, A. mellifera vitellogenin resolved into a single band with an apparent Mr of 180,000. Gel filtration under reducing and native conditions yielded estimated Mr values of about 300,000.  相似文献   

14.
The hydrophilic head of melittin (peptide from bee venom) has the amino acid sequence which is very close to the amino acid sequence of C1q-binding site of the IgG molecule. It was shown, that melittin caused the multiple growth of the interaction of C1q with IgG monoclonal antibody. We assume, that the appearance of melittin in blood causes the spontaneous antigen-independent aggregation of IgG and C1q with the following triggering of the classical pathway of the complement cascade and origin of C3a and C5a components. This can be one of the mechanisms of anaphylaxis as an answer to bee venom.  相似文献   

15.
Honey bee queens have the ability to store sperm in spermathecae for fertilizing eggs throughout their life. To investigate mechanisms for sperm storage in Apis mellifera, we employed suppression subtractive hybridization (SSH) to find differentially expressed fragments in spermathecae between virgin queens and newly mated queens. A new gene, named SRP16, was obtained by joining the SSH products with 5′-RACE and 3′-RACE. SRP16 is predicted to encode a 41?kDa protein with 363 amino acid residues. Its expression was found in the spermathecae dominantly in honey bee queens but not in honey bee workers, with the highest expression found in spermathecae of virgin and newly mated queens. SRP16 expression was weak in other tissues of queens other than in the spermathecae and showed no obvious change with reproductive status of queens. The results suggest that SRP16 may play important roles in sperm storage and honey bee reproduction.  相似文献   

16.
Abstract The venomous hyaluronidase (Hya) gene of Chinese honey bee, Apis cerana cerana, was amplified by RT‐PCR from total RNA of venom glands of the worker bees. The full length of its nucleotide is 1164 bp encoding a 387 amino acid polypeptide with predicted molecular weight of 42.6 kD. The alignment of AcHya amino acid sequence with other 6 Hyas shows that AcHya is most closely related to the Hya of European honey bee, A. mellifera, with 91% amino acid identity. It also shares homology with Hya of Dolichovespul amacidata, Polistes annularis, Vespula vulgaris, Lutzomia longipalpis and Homo sapiens (sperm), with 54%., 52%., 46%, 27% and 20% amino acid identity, respectively. A phylogenetic tree of those hyaluronidases was drawn by using GENETYX program, the conservation, the relationship between molecular structure and function of 7 hyaluronidases as above was compared and analysed.  相似文献   

17.
The first representative of a group of mammalian, low molecular weight phosphotyrosyl protein phosphatases was cloned, sequenced and expressed in Escherichia coli. Using a 61-mer oligonucleotide probe based on the amino acid sequence of the purified enzyme, several overlapping cDNA clones were isolated from a bovine heart cDNA library. A full-length clone was obtained consisting of a 27-bp 5' noncoding region, an open reading frame encoding the expected 157 amino acid protein, and an extensive 3' nontranslated sequence. The identification of the clone as full length was consistent with results obtained in mRNA blotting experiments using poly(A)+ mRNA from bovine heart. The coding sequence was placed downstream of a bacteriophage T7 promoter, and protein was expressed in E. coli. The expressed enzyme was soluble, and catalytically active and was readily isolated and purified. The recombinant protein had the expected Mr of 18,000 (estimated by SDS-PAGE), and it showed cross-reactivity with antisera that had been raised against both the bovine heart and the human placenta enzymes. The amino acid sequence of the N-terminal region of the expressed protein showed that methionine had been removed, resulting in a sequence identical to that of the enzyme isolated from the bovine tissue, with the exception that the N-terminal alanine of the protein from tissue is acetylated. A kinetically competent phosphoenzyme intermediate was trapped from a phosphatase-catalyzed reaction. Using 31P NMR, the covalent intermediate was identified as a cysteinyl phosphate. By analogy with the nomenclature used for serine esterases, these enzymes may be called cysteine phosphatases.  相似文献   

18.
19.
The soluble proteins of the eggs of the coleopteran insect Anthonomus grandis Boheman, the cotton boll weevil, consist almost entirely of two vitellin types with Mrs of 160,000 and 47,000. We sequenced their N-terminal ends and one internal cyanogen bromide fragment of the large vitellin and compared these sequences with the deduced amino acid sequence from the vitellogenin gene. The results suggest that both the boll weevil vitellin proteins are products of the proteolytic cleavage of a single precursor protein. The smaller 47,000 M vitellin protein is derived from the N-terminal portion of the precursor adjacent to an 18 amino acid signal peptide. The cleavage site between the large and small vitellins at amino acid 362 is adjacent to a pentapeptide sequence containing two pairs of arginine residues. Comparison of the boll weevil sequences with limited known sequences from the single 180,000 Mr honey bee protein show that the honey bee vitellin N-terminal exhibits sequence homology to the N-terminal of the 47,000 Mr boll weevil vitellin. Treatment of the vitellins with an N-glycosidase results in a decrease in molecular weight of both proteins, from 47,000 to 39,000 and from 160,000 to 145,000, indicating that about 10–15% of the molecular weight of each vitellin consists of N-linked carbohydrate. The molecular weight of the deglycosylated large vitellin is smaller than that predicted from the gene sequence, indicating possible further proteolytic processing at the C-terminal of that protein. © 1993 Wiley-Liss, Inc.
  • 1 This article is a US Government work and, as such, is in the public domain in the United States of America.
  •   相似文献   

    20.
    The crystalline beef liver protein of Sumner and Dounce (A. L. Dounce, P. Z. Allen, and G. A. Mourtzikos (1978) Arch. Biochem. Biophys. 188, 251-265) termed FTBL (football) protein because of the shape of its crystals, has been identified as a crystalline leucine aminopeptidase (LAP), on the basis of its high specific LAP activity and coincidence of its N terminal amino acid sequence (30 amino acids) with that of beef eye lens LAP. Amino acid analyses of the two proteins are also in reasonable agreement when based on the exact monomer molecular weight of beef eye lens protein obtained by the van Loon group ((1982) J. Biol. Chem. 257, 7077-7081). Our previously published monomer molecular weight of the FTBL protein was 25% too high, leading to the erroneous conclusion that the beef liver FTBL-LAP protein was a tetramer rather than a hexamer, as found by the van Loon group for beef lens LAP. The present report, taken together with our first paper on the FTBL protein establishes that the FTBL-LAP protein has been isolated from beef kidney and beef spleen as well as from beef liver. We now find that the properties of FTBL-LAP protein indicate that it is the same protein as beef eye lens LAP. The cellular and intracellular distributions of the FTBL-LAP protein have been considered in our first publication on the FTBL protein.  相似文献   

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