香鳞毛蕨DfDREB基因克隆与表达模式分析

DREB(dehydration-responsive element-binding)转录因子是响应非生物胁迫反应的主要调节因子,为探索DREB在多年生草本药用植物香鳞毛蕨[Dryopteris fragrans(L.) Schott]抗逆过程中的功能,该研究克隆了DfDREB基因并进行生物信息学分析,采用qRT-PCR方法分析了DfDREB基因在不同激素及干旱、NaCl、高温和低温等逆境胁迫处理下的表达模式。结果表明:(1)成功获得DfDREB基因全长1 203 bp,其编码401个氨基酸,相对分子质量为43.66 kD,等电点为6.13,是亲水性非分泌蛋白,该蛋白具有AP2保守结构域,属于AP2家族。(2)实时荧光定量PCR分析表明,DfDREB基因在香鳞毛蕨根、叶柄和叶中均有表达,其中在叶中表达量最高,根中表达量最低;在水杨酸(SA)、茉莉酸甲酯(MeJA)和乙烯利(ETH)处理时,DfDREB基因表达上调,并都在1 h时表达量达到峰值;在脱落酸(ABA)处理时,DfDREB基因的相对表达量仅在12 h和24 h时呈上调表达,其余时间为下调表达;在干旱、NaCl和高温处理时,DfDREB基因表达均上调;低温处理0.5 h和12 h时DfDREB基因表达显著上调,但在低温处理1～6 h和24 h时无明显变化。研究表明,DfDREB基因响应激素和非生物胁迫处理,且基因表达受胁迫诱导。该研究结果为进一步探索香鳞毛蕨抗逆分子机制奠定了基础。     

水曲柳BZR1基因克隆及其表达模式分析

研究水曲柳BZR1基因应答非生物胁迫及激素信号的表达模式,对探究BR在水曲柳生长发育及响应环境胁迫方面的作用有重要意义。本研究以水曲柳为材料,PCR克隆得到目的基因,通过生物信息学软件分析分子结构特征,利用荧光定量PCR探究FmBZR1在低温、盐胁迫及ABA、IAA、GA3诱导下的表达模式。生物信息学分析表明,FmBZR1基因全长984 bp,编码327个氨基酸,FmBZR1蛋白为亲水性蛋白,与樟子松BZR1蛋白的同源性较高。在非生物胁迫与激素诱导下,结果表明,与对照组相比,FmBZR1基因表达量有显著差异。低温处理6 h、盐处理24 h后表达量最高,分别为对照组的1.98、10.13倍。ABA、IAA、GA3处理3 h后基因表达量最低,分别为对照组的0.52、0.41、0.50倍;GA3处理24h后基因表达量最高,为对照组的6.23倍。FmBZR1基因在水曲柳生长发育及各种胁迫应答的过程起到了十分关键的作用。     

植物激素处理和环境胁迫对‘金魁’猕猴桃AdRAVs基因表达特性的影响

以‘金魁’猕猴桃(Actinidia deliciosa‘Jinkui’)组培苗及2年生扦插苗为实验材料,采用qRT-PCR技术对0.1 mmol·L-1水杨酸(SA)、0.05 mmol·L-1茉莉酸甲酯(MeJA)、0.01 mmol·L-11-氨基环丙烷-1-羧酸(ACC)和0.01 mmol·L-1脱落酸(ABA)4种植物激素处理后0、4、12和48 h,低温(4℃)和0.2 mol·L-1 NaCl胁迫0、4、12和48 h,高温(48℃)胁迫0、2和4 h及恢复培养6 h,以及干旱胁迫14 d后叶片中AdRAV1、AdRAV2和AdRAV3基因的相对表达量进行了测定。结果显示：不同处理条件下3个AdRAVs基因相对表达量的变化存在一定差异。 SA、MeJA和ACC处理后4和12 h,AdRAV1基因的相对表达量显著(P<0.05)升高,但ABA处理后该基因的相对表达量无明显变化;SA、MeJA、ACC和ABA处理后48 h,AdRAV2基因的相对表达量显著降低;4种植物激素处理后4、12和48 h,AdRAV3基因的相对表达量总体上显著降低。低温胁迫下,AdRAV1和AdRAV2基因的相对表达量无明显变化,但胁迫48 h时AdRAV3基因的相对表达量却显著升高。 NaCl胁迫12 h时,AdRAV1和AdRAV2基因的相对表达量均显著升高,而AdRAV3基因的相对表达量则显著降低。高温胁迫4 h时, AdRAV1基因的相对表达量显著降低, AdRAV2基因的相对表达量显著升高;胁迫2 h时,AdRAV3基因的相对表达量显著降低;恢复培养6 h时,3个基因的相对表达量均无法恢复至起始水平。干旱胁迫14 d后,AdRAV1基因的相对表达量显著高于对照(正常浇水);AdRAV2的相对表达量高于对照,而AdRAV3基因的相对表达量则低于对照,且均与对照无显著差异。研究结果表明：不同胁迫条件对‘金魁’猕猴桃AdRAVs基因的表达特性有不同诱导效应。根据实验结果,推测AdRAV1、AdRAV2和AdRAV3基因可能参与SA、MeJA、ACC和ABA信号转导途径以及耐盐和耐高温过程;并且,AdRAV1基因还可能参与耐旱过程,而AdRAV3基因则可能参与耐寒过程。     

朝鲜淫羊藿EkCDPK基因的克隆及表达分析

钙依赖蛋白激酶(Calcium-Dependent Protein Kinase, CDPK)是在植物抗逆胁迫信号转导途径中起关键作用的酶。该研究采用RT-PCR结合RACE技术,从朝鲜淫羊藿(Epimedium koreanum Nakai)中克隆获得一个全长2 036 bp的钙依赖蛋白激酶基因(EkCDPK)。结果显示:(1)EkCDPK基因cDNA为1 410 bp,5′-UTR长387 bp, 3′-UTR长239 bp,编码469个氨基酸。EkCDPK蛋白保守结构域N端为S_TKc domain,C端为EF-hand domain,该蛋白具有1个CDPKs典型结构Ser/Thr蛋白激酶活性位点、1个ATP位点、4个Ca~(2+)结合位点、1个跨膜结构域、无信号肽的稳定亲水性蛋白质,二级结构主要由α-螺旋(43.71%)和无规则卷曲(37.10%)构成。(2)系统进化分析表明,EkCDPK与菘蓝CDPK蛋白表现出较高相似性(95%)。(3)实时荧光定量PCR分析表明,EkCDPK基因在根、茎、叶与花组织中均有表达,根中表达量最高,茎次之;干旱胁迫后15 h内表达量显著高于对照组,之后表达量开始下降;盐胁迫5、15和25 h后EkCDPK基因表达量均明显高于对照组。(4)成功构建了pET-28a-EkCDPK原核表达载体,诱导出约50 kD蛋白质,与预测大小一致,表明重组蛋白EkCDPK表达成功,为采用基因工程手段提高朝鲜淫羊藿抗逆性能研究奠定了基础。     

香蕉MaPIP2-6基因的克隆、亚细胞定位及表达分析

该研究从香蕉中克隆了一个水通道蛋白(AQP)基因MaPIP2-6。序列分析表明,MaPIP2-6基因开放阅读框(ORF)为849bp,编码282个氨基酸。多序列比对和进化树分析表明,MaPIP2-6基因所编码的蛋白与其它植物中AQP蛋白具有较高的一致性,并且与水稻OsPIP2-6的亲缘关系最近。亚细胞定位表明,MaPIP2-6基因定位在细胞膜上。实时荧光定量PCR分析表明,甘露醇和高盐胁迫处理下,MaPIP2-6基因在巴西蕉和粉蕉中的表达趋势基本一致,在处理早期表达量轻微下降,随后被诱导并达到最大值,然后下降;在低温和ABA处理下,MaPIP2-6基因在巴西蕉和粉蕉的表达趋势相反,低温处理47h时,巴西蕉的MaPIP2-6表达量显著降低,而粉蕉无显著变化,但在其他时间点,巴西蕉的表达量无显著变化,粉蕉显著降低。ABA处理下,MaPIP2-6基因在巴西蕉被诱导,而在粉蕉被抑制。研究认为,MaPIP2-6可能参与了非生物逆境胁迫应答,为进一步研究MaPIP2-6基因的功能鉴定了基础。     

陆地棉GhCSN6A基因克隆及低磷胁迫下的表达

该研究基于陆地棉根部低磷胁迫基因表达谱芯片差异表达序列结果及基因组数据库，对表达差异序列ES816317进行克隆，利用生物信息学分析其核苷酸及蛋白序列，并通过qRT-PCR技术检测其组织表达模式和在低磷胁迫下的相对表达特征，为解析棉花GhCSN6A的生物学功能奠定基础，并为棉花磷高效基因工程育种提供基因资源。结果表明：(1)成功获得陆地棉GhCSN6A基因，该基因的开放阅读框全长为948 bp,编码315个氨基酸；GhCSN6A蛋白为COP9信号小体复合亚基6a,属于MOV34蛋白超家族，具有MPN＿CSN6结构域，定位于细胞核。(2)序列比对和进化分析显示，陆地棉GhCSN6A与木槿HsCSN6A、拟南芥AtCSN6A的相似性分别为95.87%和84.54%。(3)qRT-PCR分析表明，GhCSN6A基因在陆地棉的根、茎、叶、花中均有表达，且在叶中表达水平最高，但叶与根中的表达无显著差异；GhCSN6A基因在低磷处理24 h时根中相对表达量最低，但低磷处理72 h时根中的相对表达量最高达到了适磷(对照)处理的2倍。研究推测，陆地棉GhCSN6A基因在棉花响应低磷胁迫过程中具有重要作...     

甘菊ClHSP70与ClHSP90基因的克隆及表达分析

该研究以甘菊(Chrysanthemum lavandulifolium)为实验材料,通过RT-PCR方法从甘菊转录组数据中分离出热激蛋白合成相关基因,命名为ClHSP70和ClHSP90。序列分析表明,ClHSP70基因ORF全长为2 559bp,编码852个氨基酸,蛋白功能区预测表明含有典型的HSP70蛋白NBD和SBD保守结构域;ClHSP90基因ORF全长为2 094bp,编码697个氨基酸,含有HATPase结构域和HSP90保守结构域。生物信息学分析表明,甘菊ClHSP70与大豆(Glycine max)和烟草(Nicotiana tomentosiformis)HSP70蛋白有较高的一致性,ClHSP90基因编码的氨基酸序列与紫茎泽兰(Ageratina adenophora)HSP90高度相似;实时荧光定量表达分析表明,在42℃处理不同时间,甘菊叶片中ClHSP70和ClHSP90基因表达均在0.5h时显著增加,1h达到最大值,2h后缓慢下降;不同组织表达分析表明,甘菊在42℃处理1h后,ClHSP70在成熟叶中的表达量显著高于嫩叶和根等其他组织;ClHSP90在成熟茎中的表达量最高。研究说明,ClHSP70和ClHSP90基因具有热激蛋白特征,参与了甘菊热胁迫应答过程,该研究结果为以后深入研究其基因功能奠定了基础。     

干旱胁迫下棉花幼苗转录因子BES1/BZR1对外源油菜素内酯的响应表达特征

植物激素油菜素内酯(Brassinosteroid,BR)具有提高植物抗旱性的作用,该研究探讨干旱胁迫下外源喷施BR对棉花干旱胁迫响应基因表达的影响。采用PCR方法从棉花‘新陆早17号’幼苗克隆获得1个干旱胁迫响应转录因子基因,命名为GhBES1/BZR1(GenBank登录号KP272000)。序列分析表明GhBES1/BZR1基因开放阅读框为960bp,编码319个氨基酸,理论分子量为34.3kD,理论等电点为8.95。保守结构域分析显示,该基因编码的蛋白具有一个DUF822保守结构域。利用2.5%PEG-6000对棉花‘新陆早17号’幼苗进行干旱胁迫处理24h,再分别喷施水、BR和Z(BR抑制剂),qRT-PCR分析结果表明,PEG-6000干旱胁迫下用BR处理3h后,GhBES1/BZR1基因表达量明显提高,当BR处理6和12h时,GhBES1/BZR1基因的表达量较3h时明显下降。研究认为,在干旱胁迫下对棉花喷洒BR,GhBES1/BZR1基因能够快速表达以响应干旱胁迫,外源喷施BR有助于提高棉花的抗旱能力。     

西葫芦NCED基因家族鉴定及其响应干旱胁迫分析

NCED基因家族成员在调节植物响应干旱胁迫中发挥着关键作用,该研究通过生物信息学技术分析NCED在西葫芦基因组中的分布、结构及进化,研究家族成员在不同组织中的表达特异性及其对10%PEG 6000模拟干旱、0.1 mmol·L-1ABA激素和自然干旱胁迫的响应,以解析NCED基因家族的生物学功能。结果表明:(1)从西葫芦全基因组中鉴定出6个NCED家族基因(CpNCED1~6),且6个基因均不含内含子、分别分布于西葫芦的1、10、12、14、19和20号共6条染色体上。(2)理化性质分析发现,CpNCED1~6蛋白长度为569~590 aa,理论分子量在62.64~65.54 kD之间。(3)蛋白保守元件分析显示,除CpNCED3蛋白在遗传进化过程中出现3个基序(motif 12、motif 13和motif 15)的缺失外,其余5个蛋白都有完整的16个motif保守基序,且分布在600个氨基酸以内,同时大部分NCED蛋白序列保守性较高。(4)顺式作用元件分析显示,西葫芦CpNCED1~6基因均含ABRE、W box、MBS、P-box、TCA-element、CGTCA-motif、TGA-element和TGA-box等潜在的干旱胁迫响应元件。(5)qRT-PCR分析表明,CpNCED1~6基因在西葫芦不同组织中的表达具有组织特异性,其中,CpNCED4和CpNCED1在茎中的表达量显著高于其他4个基因,CpNCED2、CpNCED4、CpNCED6在花中的表达显著高于其余3个基因且CpNCED2表达量最高,CpNCED1~6在果实和叶中的表达量均相对较低;与对照组相比,CpNCED1~6受模拟干旱、ABA激素和自然干旱胁迫均上调表达;伴随干旱胁迫的产生,叶片中脱落酸(ABA)含量逐渐升高,暗示CpNCEDs在西葫芦干旱胁迫响应与ABA的生物合成过程中发挥着正向调控作用。研究发现,6个CpNCED1~6基因与西葫芦干旱胁迫响应密切相关,且对西葫芦干旱胁迫的响应以及ABA生物合成具有重要作用,尤其以CpNCED2和CpNCED4基因的作用更为明显。     

小麦TaCO9基因的克隆及功能分析

为了明确TaCO9-1A基因在小麦生长发育中的具体调控机理,该研究以同源克隆的方法成功获得了大麦(Hordeum vulgare)光周期基因HvCO9在小麦(Triticum aestivum)中的直系同源基因TaCO9,并对其进行生物信息学分析、亚细胞定位、转录激活以及表达模式分析;利用农杆菌侵染法转化拟南芥,并对过表达株系进行表型分析。结果表明:(1)TaCO9包含2个外显子和1个内含子,CDS区全长876 bp,编码291个氨基酸,蛋白序列含有特有的CCT结构域,且在不同物种间高度保守。(2)生物信息学分析表明,TaCO9基因编码的蛋白质分子量约为30.7 kD,等电点为6.24;TaCO9的启动子区含有光响应、激素应答和胁迫应答等多种顺式作用元件。(3)亚细胞定位和转录活性分析表明,TaCO9主要定位于细胞核中,且具有转录激活活性。(4)qRT-PCR结果表明,TaCO9基因在各个组织中均有表达,叶片中的表达量最高;在光照14 h条件下TaCO9的表达量显著高于光照10 h和12 h条件下的表达量,且TaCO9在大粒小麦‘西农817’子房与籽粒中的表达量显著高于‘中国春’。(5)经潮霉素筛选成功获得3个转基因拟南芥株系;进一步功能鉴定结果表明,过表达转TaCO9基因拟南芥植株的开花期迟于野生型(对照)3~4 d,但角果和籽粒较野生型大。     

Presence of Rhizobium Etli bv . Phaseoli and Rhizobium Gallicum bv . Gallicum in Egyptian Soils

Seven bean rhizobial strains EBRI 2, 3, 21, 24, 26, 27 and 29 identified as Rhizobium etli, and EBRI 32 identified as Rhizobium gallicum, isolated from Egyptian soils and which nodulated Phaseolus vulgaris efficiently, were subjected to hybridization with a nifH probe in order to estimate the copy number of this gene. Seven strains (EBRI 2, 3, 21, 24, 26, 27 and 29) which were only able to nodulate Phaseolus vulgaris, contained three copies of the nifH gene, consistent with their identification as Rhizobium etli bv. phaseoli. Only one strain (EBRI 32) which nodulated both Phaseolus vulgaris and Leucaena leucocephala, had one copy of nifH gene. This confirmed the classification of this strain as Rhizobium gallicum bv. gallicum.     

Effects of MULTIFOLIATE-PINNA, AFILA, TENDRIL-LESS and UNIFOLIATA genes on leafblade architecture in Pisum sativum

In order to dissect the genetic regulation of leafblade morphogenesis, 16 genotypes of pea, constructed by combining the wild-type and mutant alleles of MFP, AF, TL and UNI genes, were quantitatively phenotyped. The morphological features of the three domains of leafblades of four genotypes, unknown earlier, were described. All the genotypes were found to differ in leafblade morphology. It was evident that MFP and TL functions acted as repressor of pinna ramification, in the distal domain. These functions, with and without interaction with UNI, also repressed the ramification of proximal pinnae in the absence of AF function. The expression of MFP and TL required UNI function. AF function was found to control leafblade architecture multifariously. The earlier identified role of AF as a repressor of UNI in the proximal domain was confirmed. Negative control of AF on the UNI-dependent pinna ramification in the distal domain was revealed. It was found that AF establishes a boundary between proximal and distal domains and activates formation of leaflet pinnae in the proximal domain.     

Prosthecium species with Stegonsporium anamorphs on Acer

Data from microscopic morphology, single-spore cultures, and DNA analyses of teleomorphs and anamorphs support the recognition of five species of Prosthecium with Stegonsporium anamorphs on Acer: P. acerinum sp. nov., the teleomorph of S. acerinum; P. acerophilum comb. nov., formerly known as Dictyoporthe acerophila; P. galeatum comb. nov., originally described as Massaria galeata; P. opalus sp. nov.; and P. pyriforme sp. nov., the teleomorph of S. pyriforme s. str. The morphology of both type specimens and freshly collected material was investigated. The teleomorphs have brown ellipsoidal ascospores with five distosepta and often a longitudinal distoseptum. The anamorphs of all species described here belong to Stegonsporium; their connection to the Prosthecium teleomorphs was demonstrated by morphology and DNA sequences of single spore cultures derived from both ascospores and conidia. The anamorphs and teleomorphs of all five Prosthecium species are described and illustrated by LM images, and a key to these species is provided. As perceived from this work, S. pyriforme is restricted to Europe and does not occur in North America, whereas S. acerinum is restricted to North America, not found in Europe. The host associations given in the literature are revised and evidence is provided that only A. opalus, A. pseudoplatanus, and A. saccharum are confirmed hosts of Prosthecium with Stegonsporium anamorphs. Molecular phylogenetic analyses of tef1, ITS rDNA, and partial nuLSU rDNA sequences confirm that the species with Stegonsporium anamorphs are closely related to P. ellipsosporum, the generic type species. Stilbospora macrosperma is confirmed as the anamorph of P. ellipsosporum by DNA data of single spore isolates obtained from both ascospores and conidia.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

中国黑粉菌属和利罗黑粉菌属

黑粉菌属是Roussel 1806年建立的,全世界记载有三百余种,主要寄生于禾本科,是经济作物及牧草的重要致病菌·长期以来,对黑粉菌的邢子使用过各种名称,如厚垣孢子,冬孢子及黑粉孢子等.本文采用黑粉孢子以区别锈菌的冬孢子. 芳’(1979)在《中国真菌总汇》中列出黑粉菌属五十种及一个变型.作者经过显微结构和超显微结构的研究,承认其中二十九种为正确名称,八种及一变型为异名,顶黑粉菌(Ustilago acrearus Berk.)由于错拼而被废弃.埃地黑粉菌(Ustilago emodensis Berk.)被转移至利罗粉菌属(Liroa).另有十一种黑粉菌因缺少标本留待今后订正.自1979年以后,杨信东(1983)增加黑粉菌属二种我国新纪录,K.范基和郭林(1986)描述一新种,四种新纪录.在本文中,作者描述一新种:鸢尾蒜黑粉(Ustilago ixiolirii Guo L) ,孢子堆生在蒴果内,不开裂,黑色,粉末状.黑粉孢子球形,近球形,稀椭圆形, 12.5-21×10-21μm,黑褐色,壁厚1-1.Sμm,纹饰脑状.是迄今生在石蒜科植物上唯一黑粉菌的种,其它几种黑粉菌均属条黑粉菌属.本文增加七种我国新纪录.共计四十九种,寄生于六科四十四属植物,主要是禾本科和蓼科.这仅是黑粉菌属研究的初步报告,在全国范围内大量采集黑粉菌标本后,作者相信会有更多新种和我国新纪录被发现.利罗黑粉菌属(Liroa)是从黑粉菌属(Ustaligo)分出的,此属为单种属.     

Comparative study of Bifidobacteriumanimalis, Escherichiacoli, Lactobacilluscasei and Saccharomycesboulardii probiotic properties

The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.     

Probing the Drosophila retinal determination gene network in Tribolium (II): The Pax6 genes eyeless and twin of eyeless

The Pax6 genes eyeless (ey) and twin of eyeless (toy) are upstream regulators in the retinal determination gene network (RDGN), which instructs the formation of the adult eye primordium in Drosophila. Most animals possess a singleton Pax6 ortholog, but the dependence of eye development on Pax6 is widely conserved. A rare exception is given by the larval eyes of Drosophila, which develop independently of ey and toy. To obtain insight into the origin of differential larval and adult eye regulation, we studied the function of toy and ey in the red flour beetle Tribolium castaneum. We find that single and combinatorial knockdown of toy and ey affect larval eye development strongly but adult eye development only mildly in this primitive hemimetabolous species. Compound eye-loss, however, was provoked when ey and toy were RNAi-silenced in combination with the early retinal gene dachshund (dac). We propose that these data reflect a role of Pax6 during regional specification in the developing head and that the subsequent maintenance and growth of the adult eye primordium is regulated partly by redundant and partly by specific functions of toy, ey and dac in Tribolium. The results from embryonic knockdown and comparative protein sequence analysis lead us further to conclude that Tribolium represents an ancestral state of redundant control by ey and toy.     

Doc and copia instability in an isogenic Drosophila melanogaster stock

A high degree of heterogeneity and an overall increase in number of insertion sites of the mobile elements Doc and copia were revealed in one substock of an isogenic Drosophila melanogaster stock, while in two other substocks the distribution of copia sites was highly homogenous, but that of Doc sites was again heterogenous. We therefore concluded that copia was unstable in one of the substocks and Doc was unstable in all. Doc instability presumably arose earlier than copia instability. Doc and copia transpositions were directly observed in experiments with one substock. An abundance of copia insertions was revealed in the X chromosome where insertions with deleterious effects are exposed to selection in hemizygous condition. The locations of many other mobile elements (mdg1, mdg2, mdg3, mdg4, 297, B104, H.M.S. Beagle, I, P, BS, FB) were found to be conserved in each substock and did not differ between them, indicating that these mobile elements were stable. This homogeneity is a strong argument against any possibility of inadvertent contamination.