./抗菌肽基因及研究進展摘要抗菌肽是昆蟲先天性免疫系統中十分重要的效應因子,近年來一直是昆蟲免疫學研究的熱點。家蠶作為鱗翅目昆蟲的代表,其抗菌肽研究取得了長足進展。根據過去研究獲得的抗菌肽基因,并利用這些序列在家蠶基因組中進行同源搜尋,共發現了40個家蠶抗菌肽基因。這些基因編碼的多肽在大小、氨基酸組成和性質上差異很大,但基于結構性質可以分成3類：<1>具有α-螺旋結構并且缺乏半胱氨酸<Cysteine,Cys>的線性抗菌肽；<2>富含脯氨酸和/或甘氨酸的抗菌肽;<3>富含半胱氨酸的環形抗菌肽。本文將以這3類結構作為主線綜述家蠶抗菌肽近年來的研究進展。關鍵詞家蠶；抗菌肽；結構AntimicrobialPeptideGenesinBombyxmoriandTheirResearchProgressSUNWei1,SHENYihong1,XIANGZhonghuai1,ZHANGZe1,2〔1.ThekeySericulturalLaboratoryofAgriculturalMinistry,SouthwestUniversity,Chongqing400716,China.2.TheInstituteofAgriculturalandLifeSciences,Chongqing400030,ChinaAbstractAntimicrobialpeptidesaretheimportanteffectorsoftheinnateimmunesystemininsects,whicharealwaysthehotresearchoftheinsectimmune.SilkwormistherepresentativeoftheLepidoptera,andtheresearchesofantimicrobialpeptidesinsilkwormmakeagreatprogress.AlocalBLASTsearchofthesilkwormgenomedatabaseidentified40antimicrobialpeptidegenes.Thoughthepeptidesencodedbythesegeneshavegreatdifferencesinsize,aminoacidcompositionandproperties,theycouldbegroupedinto3categories:<1>linearpeptidesformingα-helicesandwithoutcysteineresidues;<2>cyclicpeptidescontainingcysteineresidues;<3>peptideswithanoverrepresentationinprolineand/orglycineresidues.Thereviewpresentsthemainresearchesinthefieldofantimicrobialpeptidesfromsilkwormwiththesethreeaspectsduringtheseyears.KeywordsBombyxmori;antimicrobialpeptides;structure昆蟲是一類進化上較為低等的動物,同時也是世界上種類和數量最多的動物。面對大量的外源微生物的侵害,雖然沒有類似于哺乳動物的特異性免疫系統,但是仍然能夠較好的生存,說明昆蟲必定有對非特異因子產生免疫應答的高效先天免疫系統。昆蟲的免疫系統由體液免疫和細胞免疫組成。細胞免疫主要是血細胞吞噬和消化外來異物,與高等動物類似。黑化反應也是昆蟲重要的細胞免疫,血淋巴和血細胞中,當外源物侵入昆蟲血腔時,激發了絲氨酸蛋白酶的級聯反應形成黑色素。這樣,當酚氧化酶沉積在外源微生物表面時,可形成能阻止其生長和運動并且將其與寄主組織隔離的黑化包囊ADDINEN.CITE<EndNote><Cite><Author>Kimbrell</Author><Year>2001</Year><RecNum>79</RecNum><record><rec-number>79</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kimbrell,D.A.</author><author>Beutler,B.</author></authors></contributors><auth-address>DepartmentofMolecularandCellularBiology,UniversityofCalifornia,1ShieldsAvenue,Davis,California95616-8535,USA.dakimbrell@</auth-address><titles><title>Theevolutionandgeneticsofinnateimmunity</title><secondary-title>NatRevGenet</secondary-title></titles><periodical><full-title>NatRevGenet</full-title></periodical><pages>256-67</pages><volume>2</volume><number>4</number><keywords><keyword>Animals</keyword><keyword>Apoptosis</keyword><keyword>Drosophila/genetics/*immunology/microbiology</keyword><keyword>*DrosophilaProteins</keyword><keyword>*Evolution</keyword><keyword>Humans</keyword><keyword>Immunity,Natural/*genetics/*immunology</keyword><keyword>Infection/immunology</keyword><keyword>InsectProteins/genetics/*immunology</keyword><keyword>Interleukin-1/chemistry/genetics/immunology</keyword><keyword>MembraneGlycoproteins/genetics/*immunology</keyword><keyword>Phylogeny</keyword><keyword>Receptors,CellSurface/genetics/immunology</keyword><keyword>SignalTransduction</keyword><keyword>Toll-LikeReceptor5</keyword><keyword>Toll-LikeReceptors</keyword></keywords><dates><year>2001</year><pub-dates><date>Apr</date></pub-dates></dates><accession-num>11283698</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11283698</url></related-urls></urls></record></Cite></EndNote>[1]。由于沒有抗體和補體系統,昆蟲的體液免疫與高等動物有明顯差異,主要依賴血液中的抗菌肽和蛋白質ADDINEN.CITE<EndNote><Cite><Author>Kimbrell</Author><Year>2001</Year><RecNum>79</RecNum><record><rec-number>79</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kimbrell,D.A.</author><author>Beutler,B.</author></authors></contributors><auth-address>DepartmentofMolecularandCellularBiology,UniversityofCalifornia,1ShieldsAvenue,Davis,California95616-8535,USA.dakimbrell@</auth-address><titles><title>Theevolutionandgeneticsofinnateimmunity</title><secondary-title>NatRevGenet</secondary-title></titles><periodical><full-title>NatRevGenet</full-title></periodical><pages>256-67</pages><volume>2</volume><number>4</number><keywords><keyword>Animals</keyword><keyword>Apoptosis</keyword><keyword>Drosophila/genetics/*immunology/microbiology</keyword><keyword>*DrosophilaProteins</keyword><keyword>*Evolution</keyword><keyword>Humans</keyword><keyword>Immunity,Natural/*genetics/*immunology</keyword><keyword>Infection/immunology</keyword><keyword>InsectProteins/genetics/*immunology</keyword><keyword>Interleukin-1/chemistry/genetics/immunology</keyword><keyword>MembraneGlycoproteins/genetics/*immunology</keyword><keyword>Phylogeny</keyword><keyword>Receptors,CellSurface/genetics/immunology</keyword><keyword>SignalTransduction</keyword><keyword>Toll-LikeReceptor5</keyword><keyword>Toll-LikeReceptors</keyword></keywords><dates><year>2001</year><pub-dates><date>Apr</date></pub-dates></dates><accession-num>11283698</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11283698</url></related-urls></urls></record></Cite></EndNote>[2]。當昆蟲機體受到病原微生物侵染時,體內的識別蛋白能夠識別微生物表面的肽聚糖或脂多糖或者其他物質,引發絲氨酸蛋白酶和解除絲氨酸蛋白酶抑制劑的細胞外級聯反應,激活細胞內信號轉導途徑,最終在其脂肪體、血液、中腸和表皮等器官或組織中誘導產生抗菌肽〔Antimicrobialpeptides,AMPs,進而殺滅外源微生物ADDINEN.CITE<EndNote><Cite><Author>Kimbrell</Author><Year>2001</Year><RecNum>79</RecNum><record><rec-number>79</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Kimbrell,D.A.</author><author>Beutler,B.</author></authors></contributors><auth-address>DepartmentofMolecularandCellularBiology,UniversityofCalifornia,1ShieldsAvenue,Davis,California95616-8535,USA.dakimbrell@</auth-address><titles><title>Theevolutionandgeneticsofinnateimmunity</title><secondary-title>NatRevGenet</secondary-title></titles><periodical><full-title>NatRevGenet</full-title></periodical><pages>256-67</pages><volume>2</volume><number>4</number><keywords><keyword>Animals</keyword><keyword>Apoptosis</keyword><keyword>Drosophila/genetics/*immunology/microbiology</keyword><keyword>*DrosophilaProteins</keyword><keyword>*Evolution</keyword><keyword>Humans</keyword><keyword>Immunity,Natural/*genetics/*immunology</keyword><keyword>Infection/immunology</keyword><keyword>InsectProteins/genetics/*immunology</keyword><keyword>Interleukin-1/chemistry/genetics/immunology</keyword><keyword>MembraneGlycoproteins/genetics/*immunology</keyword><keyword>Phylogeny</keyword><keyword>Receptors,CellSurface/genetics/immunology</keyword><keyword>SignalTransduction</keyword><keyword>Toll-LikeReceptor5</keyword><keyword>Toll-LikeReceptors</keyword></keywords><dates><year>2001</year><pub-dates><date>Apr</date></pub-dates></dates><accession-num>11283698</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11283698</url></related-urls></urls></record></Cite></EndNote>[1]。抗菌肽<AMPs>是一類普遍存在的防御性蛋白質,具有分子量小、理化性能穩定和廣譜抗菌等特點,在昆蟲先天免疫防御系統中起著重要的作用。昆蟲抗菌肽常以家族的形式存在,家族內成員間的氨基酸相似性較大,編碼AMPs的基因通常以串聯重復的形式存在在同一條染色體上。目前對黑腹果蠅〔Drosophilamelanogaster抗菌肽的研究較為系統,黑腹果蠅中共有21個抗菌肽,按其序列相似性和功能性質可以分為7類ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><authov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[3]。但根據肽鏈的結構特點,昆蟲抗菌肽又可以分為三類ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[4]：具有α-螺旋結構并且缺乏半胱氨酸<Cysteine,Cys>的線性抗菌肽；富含脯氨酸和/或甘氨酸的抗菌肽；富含半胱氨酸的環形抗菌肽。下面我們將以肽鏈結構分類體系介紹家蠶抗菌肽基因及其研究進展。1家蠶抗菌肽條目早在20XX,Cheng等人通過對家蠶基因組框架圖序列的找到了35條抗菌肽基因序列ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[6]。隨著研究的深入以及家蠶基因組精細圖的最近繪制完成,我們應用相同的方法重新搜尋了新組裝的家蠶基因組,并新找到一個cecropin基因,加上近期Wen等人〔2008研究發現的defensinAADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[7],以及Kaneko等人〔2008獲得的defensinBADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[8],家蠶共有40個抗菌肽基因<表1>。數量上遠比其它已測序完成的模式昆蟲—黑腹果蠅〔21個,岡比亞按蚊〔10個ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[9]和蜜蜂〔6個ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[10]多。不同昆蟲所含有的抗菌肽數目差異可能與這些物種的生活習性,棲居的環境的差異有關系。表1家蠶的抗菌肽Table1AntimicrobialpeptidesinBombyxmori抗菌肽名稱基因名稱基因數目有完整ORF的基因數目抗菌活性AttacinBmatt32抗革蘭氏陰性菌CecropinBmcec1212抗革蘭氏陽性菌,革蘭氏陰性菌和真菌EnbocinBmenb22抗革蘭氏陽性菌,革蘭氏陰性菌GloverinBmglv74抗革蘭氏陰性菌LebocinBmleb21抗革蘭氏陽性菌,革蘭氏陰性菌MoricinBmmor1212抗革蘭氏陽性菌,革蘭氏陰性菌DefensinBmdef22抗革蘭氏陽性菌,革蘭氏陰性菌總數40352線性的具有α-螺旋的抗菌肽具有α-螺旋的線性抗菌肽是一類數量較多、分布較廣的抗菌肽,從低等的節肢動物到高等的哺乳動物中都有存在,這類抗菌肽常具有兩類特征：是陽離子性質的肽；活性結構具有兩親性質,具有幾乎等量的極性氨基酸與非極性氨基酸的兩親性的α-螺旋對于穩定抗菌肽結構是十分重要的。第一個發現的α-螺旋抗菌肽是鱗翅目昆蟲惜古比天蠶〔Hyatophoracecropia的CecropinADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[11]。家蠶中屬于這種類型的抗菌肽有Cecropin、Moricin和Enbocin等三種。2.1Cecropins家族和Enbocin家族家蠶的Cecropins是一類短多肽,對革蘭氏陰性菌有強的抗菌活性,對革氏陽性菌的抗性較弱。自從在惜古比天蠶發現Cecropin以來,在鱗翅目及雙翅目昆蟲中又陸續發現了至少60種Cecropin類抗菌肽。圖1Cecropin家族和Ebocin家族以及Attacin家族抗菌肽基因在染色體上的位置。A:抗菌肽cecropin基因B-亞族,C-亞族,D-亞族和E-亞族基因以及Ebocin家族基因在第26號染色體上的位置；B:抗菌肽cecropin基因A-亞族基因BmcecA2和Attacin家族基因在第6號染色體上的位置。BmcecA1基因未能定位在染色體上。箭頭符號代表抗菌肽基因的可能的轉錄方向。Fig1ThechromosomelocationsofCecropin,EbocinandAttacingenes.A:ThelocationofCecropingenes<BmcecBs,BmcecC,BmcecDsandBmcecE>andEbocingenesonthe26thchromosome.B:ThelocationofCecropingenes<BmcecA>andAttacinsgenesonthe6thchromosome.BmcecA1cannotbelocatedonanychromosomes.Andthearrowsrepresenttheputativetranscriptorientationoftheantimicrobialpeptides.家蠶Cecropins是一個較大的家族,共有11個成員ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Trve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[6],按照它們的序列相似性分為5個亞簇—BmcecA<BmcecA1-BmcecA4>,BmcecB<BmcecB1-BmcecB5>,BmcecC<BmcecC>,BmcecD<BmcecD1-BmcecD2>和BmcecE<BmcecE>,除BmcecA外,其它9個Cecropins成員在家蠶基因組上串聯存在<圖1>。家蠶Cecropins由61-65個氨基酸組成,大多數沒有半胱氨酸,有兩個α-螺旋結構,如圖2所示,N-末端富含堿性氨基酸,C-末端富含疏水的氨基酸,并且在C-末端有酰胺化修飾,以此來增加Cecropin的穩定性以及正電荷,從而提高抗菌效率ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[12]。BmcecA1和A2,BmcecB1和B2,BmcecD以及BmcecE等6個已有研究,當受到免疫誘導時,這些基因均有明顯的表達上調,而在正常狀態下,BmcecE與另外幾個基因的表達情況有顯著的差異ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[13],胚胎發育時期,只有BmcecE在的胚帶分化時有一個表達峰,其他的基因無；在幼蟲期該7個基因有極少量或沒有表達；在蛹期,只有BmcecE在腸內有表達,這些說明BmcecE可能在胚胎發育和蛹形成時期有著重要作用。另外的6個Cecropins家族成員〔BmcecA3,BmcecA4和BmcecB3-BmcecB5以及BmcecC為在家蠶基因組精細圖繪制后,利用同源比對搜尋獲得的,活性檢測尚未有報道。但是新找到的BmcecB3-BmcecB5與BmcecB1,B2的氨基酸序列完全一致,核苷酸序列的差異也較小,只是在基因組中所處位置有所不同,推測可能具有同樣的抗菌活性。從基因組已經測序完成的幾個模式生物來看,家蠶Cecropins家族成員數目顯著比黑腹果蠅〔5個和岡比亞按蚊〔4個多,這可能與家蠶缺乏專屬的類似于果蠅中Drosomycin的抗真菌肽有關。圖2家蠶Cecropin家族成員的多序列比對及二級結構預測。紅色框表示螺旋區域,藍色框表示發夾結構。結果由PSIPRED在線網站預測。Fig.2.SequencealignmentandsecondarystructurepredictionofCecropinsinBombyx.mori.Redboxesrepresenthelix;Blueboxrepresentscoil.TheresultswereobtainedbyusingtheonlineserverofthePSIPREDProteinStructurePrediction.1998年Kim等人用探針雜交的方法在家蠶中首先發現了Enbocin的片段ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[14],Kaneko等人又在20XX獲得了3個Enbocin基因的全長序列ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[15]。從氨基酸序列來看,Enbocin屬于Cecropins家族,可能是較早從Cecropin家族中分化出來,但是它們表現出相反的抗菌活性,Cecropins抗革蘭氏陰性菌的能力更強,而Enbocin對革蘭氏陽性菌的抗性明顯強于對革蘭氏陰性菌的抗性。Cheng等人在家蠶基因組中只發現了2個編碼Enbocin基因—Bmenb1和Bmenb2,如圖1所示,這兩個基因與Cecropins基因成簇地排列在同一條染色體上,通過對Cheng等人發現的2個Enbocin與Kaneko的3個Enbocin氨基酸序列比較分析,Bmenb1和Bmenb2可以與Kaneko的Bmenb3和Bmenb2一一對應,而家蠶基因組中并未發現Kaneko所說的Bmenb,這可能是因為家蠶基因組測序并不完整所致。2.2Moricin家族Moricin是由HaraandYamakawa〔1995首先從家蠶血淋XX分離得到的ADDINEN.CITE<EndNote><Cite><Author>Hetru</Author><Year>2003</Year><RecNum>69</RecNum><record><rec-number>69</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hetru,C.</author><author>Troxler,L.</author><author>Hoffmann,J.A.</author></authors></contributors><auth-address>InstitutdeBiologieMoleculaireetCellulaire,UPR9022duCentreNationaldelaRechercheScientifique,Strasbourg,France.</auth-address><titles><title>Drosophilamelanogasterantimicrobialdefense</title><secondary-title>JInfectDis</secondary-title></titles><periodical><full-title>JInfectDis</full-title></periodical><pages>S327-34</pages><volume>187Suppl2</volume><keywords><keyword>Animals</keyword><keyword>BacterialInfections/immunology</keyword><keyword>Drosophilamelanogaster/genetics/*immunology</keyword><keyword>*Immunity,Natural</keyword><keyword>Mycoses/immunology</keyword><keyword>ParasiticDiseases,Animal/immunology</keyword><keyword>Peptides/immunology</keyword><keyword>SignalTransduction</keyword></keywords><dates><year>2003</year><pub-dates><date>Jun15</date></pub-dates></dates><accession-num>12792847</accession-num><urls><related-urls><url>/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12792847</url></related-urls></urls></record></Cite></EndNote>[16],它對革蘭氏陰性菌和革蘭氏陽性菌均有強烈的抗菌活性。家蠶抗菌肽Moricin由65-66個氨基酸殘基組成,在其N-末端部分每隔3～4個氨基酸殘基就有帶電荷氨基酸,只形成1個長的具有親水脂性質的α-螺旋結構<圖3>,在C-末端則存在堿性氨基酸殘基串,而且沒有發現Moricin有氨基酸的修飾。其抗菌機理可能是利用堿性C端與細胞膜表面作用,然后利用N端改變膜的通透性,形成離子通道ADDINEN.CITE<EndNote><Cite><Author>Hemmi</Author><Year>2002</Year><RecNum>67</RecNum><record><rec-number>67</rec-number><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Hemmi,H.</author><author>Ishibashi,J.</author><author>Hara,S.</author><author>Yamakawa,M.</author></authors></contributors><auth-address>NationalFoodResearchInstitute,2-1-12Kannondai,Tsukuba,Ibaraki305-8642,Japan.hemmi@nfri.affrc.go.jp</auth-address><titles><title>Solutionstructureofmoricin,anantibacterialpeptide,isolatedfromthesilkwormBombyxmori</ti