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1.
星鳗叶状幼体在我国东部沿海的发现   总被引:2,自引:0,他引:2  
鳗类发育阶段上的叶状幼体,早已为人们所熟知。当前的种类鉴定,主要以肌节数、色素的分布为依据。由于鳗类幼体发育阶段上的变态差异悬殊,因此,取得变态期的连续观察标本,是准确鉴定的可靠保证。国外著述虽已很多,但星鳗Astroconger myriaster(Brovoort)叶状幼体在我国尚属首次报道。  相似文献   

2.
为保护我国花鳗鲡资源,提高鳗鱼道入口吸引力,本研究以3 W水下景观灯为光源,利用自制多功能圆池设计了3种试验工况,探索花鳗鲡幼鱼的光色趋向性.结果表明: 3种试验工况下,鱼类在光区与暗区单位面积出现比例分别为(8.7±0.3)%和(3.6±1.7)%、(8.4±0.2)%和(5.0±1.4)%、(9.0±0.2)%和(1.9±1.3)%,且分布在光区的幼鱼多处于玻璃鳗发育阶段,而暗区的幼鱼多处于线鳗阶段(或向线鳗发育).光色区中鱼类出现次数百分比排在前3的分别为黄光区[(29.4±4.9)%]、红光区[(24.1±3.9)%]和紫光区[(17.2±4.0)%];黄光区[(29.4±3.3)%]、紫光区[(25.2±3.7)%]和红光区[(18.2±2.9)%];红光区[(33.3±2.3)%]、紫光区[(25.6±3.8)%]和黄光区[(20.7±5.7)%].首先进入光区次数排在前3的分别为红、黄、紫光区;红、紫、黄光区;红、紫、黄光区.鱼类在上述3种光区中的总进出次数处于蓝绿光和五彩光之间,且红光和黄光下鱼类会出现视觉疲劳.花鳗鲡幼鱼对光的趋向性由其发育阶段决定,玻璃鳗对光色具有趋向性,尤喜爱红、黄和紫光,在鳗鱼道入口采用灯光诱鱼可帮助玻璃鳗找到生长洄游通道.  相似文献   

3.
大菱鲆仔稚幼鱼消化系统发育的组织学研究   总被引:9,自引:0,他引:9  
大菱鲆(Scophthalmus maximus)是目前欧洲重要的海水养殖良种之一,在中国北方沿海大菱鲆的养殖规模也在不断扩大。有关大菱鲆消化系统个体发育方面的研究国外已有一些报道,如Sadiq等从形态学角度对大菱鲆变态发育进行了定义[1],Cousin等对大菱鲆变态前的消化系统进行了组织学研究[2],Segner等观察了大菱鲆仔稚鱼消化器官的超微结构[3]。但关于仔鱼、稚鱼和幼鱼消化系统的发育及其组织学结构的系统比较研究尚未见报道。本文对大菱鲆仔稚鱼消化系统的发育进行了组织学研究,同时选用了60日龄的幼鱼为代表,对不同发育时期大菱鲆消化系统的显微…  相似文献   

4.
OsAQP是在水稻叶片保卫细胞中高表达的液泡膜型水通道基因,为研究该基因在水稻发育过程中的表达与光敏色素光信号通路的关系,观察统计了日本晴、光敏色素突变体phyA和phyB 3个水稻品种的生长发育特征,比较了开花时间、叶片气孔密度、气孔器长等指标,并采用半定量RT-PCR以及实时定量PCR技术检测OsAQP基因在3种材料不同时期叶片中的表达特性。结果显示,光敏色素突变体phyB叶片的气孔密度、气孔器长度均低于同时期的日本晴和光敏色素突变体phyA水稻,说明光敏色素B及其相关信号可能与气孔的发育关系密切;表达模式分析显示,OsAQP基因在3个水稻品种的叶片中具有不同的表达特性,并伴随发育时期呈现下降的趋势。本研究结果说明水稻光敏色素B以及相关信号不仅与气孔的发育有关,而且可能通过与光敏色素A及相关信号通路共同调节OsAQP基因的表达,参与气孔开闭的调节。  相似文献   

5.
斜纹夜蛾Spodoptera litura是一种世界性分布的重要农业害虫, 在生长发育过程中要经历幼虫 蛹的变态发育过程。由于变态发育前后昆虫的食性发生了明显的改变, 作为食物消化吸收的中肠也发生了解体和重建。与此相适应, 昆虫中肠的各种物质和能量代谢也可能会相应地发生改变。为研究斜纹夜蛾中肠变态发育过程中糖代谢途径的变化情况, 我们从斜纹夜蛾中肠EST文库中鉴定出了12个糖代谢相关基因, 克隆了其中3个基因的全长cDNA, 并应用半定量PCR和定量PCR的方法检测了其在幼虫 蛹变态发育期中肠组织的转录表达以及对激素和饥饿等因素的响应情况。结果表明: 这3个基因(α-L-岩藻糖苷酶、 N-乙酰葡萄糖胺-6-磷酸去乙酰酶和烯醇化酶基因)的开放阅读框分别为1 461, 1 200和1 299 bp, 预测的分子量分别为56.3, 43.3和46.7 kDa。这12个糖代谢相关的基因在变态发育期的中肠组织中具有5种不同的mRNA表达模式: (Ⅰ)只在幼虫期高表达(唾液麦芽糖酶前体蛋白、 糖基水解酶31家族成员蛋白、 线粒体乙醛脱氢酶、 β-1,3 葡聚糖酶基因); (Ⅱ)只在预蛹期高表达(β-葡萄糖醛酸酶、 β-N-酰基氨基葡萄糖苷酶3基因); (Ⅲ)只在蛹期高表达(葡萄糖胺-6-磷酸异构酶基因); (Ⅳ)在预蛹期和蛹期高表达(α-葡萄糖苷酶、 α-淀粉酶、 N-乙酰葡糖胺 6 磷酸脱乙酰酶和α-L-岩藻糖苷酶基因); (Ⅴ)在变态发育期恒定表达(烯醇化酶基因)。这说明, 为适应变态发育斜纹夜蛾中肠糖代谢途径发生了明显的改变。保幼激素对这些基因的表达没有明显的影响, 但蜕皮激素对Ⅰ类基因(如糖基水解酶31家族成员蛋白基因)具有一定的抑制作用, 对Ⅲ类基因(如葡萄糖胺-6-磷酸异构酶基因)有显著的上调作用。此外, 我们还发现饥饿对几乎所有这些基因的表达都有显著的抑制作用。这些结果说明, 昆虫中肠变态发育过程中糖代谢相关基因的动态变化可能受到蜕皮激素以及饥饿相关因素的共同调控。这一研究对从代谢角度揭示昆虫变态发育的分子机理具有重要意义。  相似文献   

6.
[目的] 本文以威海天鹅湖大叶藻和日本鳗草根际沉积物为主要研究对象,探究不同生长时期的海草根际微生物群落结构多样性,并分析导致微生物群落结构差异的内在因素。[方法] 选取威海天鹅湖大叶藻和日本鳗草根际沉积物与非草区表层沉积物,采用高通量测序技术(Illumina MiSeq platform)解析海草不同生长时期下根际与非草区微生物群落特征。[结果] 微生物群落结构差异由海草生长时期以及海草是否定植共同驱动。在海草成熟期,丙酸菌属(Propionigenium)在大叶藻与日本鳗草根际有明显富集,其相对丰度分别为11.58%和14.26%;在海草幼苗期,脱硫球茎菌科(Desulfobulbaceae)在海草根际富集(大叶藻:2.299%,日本鳗草:4.092%);在海草衰退期时,硫卵菌属(Sulfurovum)的相对丰度在根际较高(大叶藻:5.624%,日本鳗草:3.749%)。此外,海草生长时期对不同样品之间微生物群落结构差异的解释度最大(R2=0.20335,P=0.002)。PICRUSt2功能预测结果表明各功能基因在海草不同生长时期所呈现的趋势一致,但丰度上呈现出幼苗期 > 成熟期 > 衰退期的结果。[结论] 天鹅湖海草床沉积物微生物群落结构在海草不同生长时期呈现不同的多样性特征,具有明显的根际效应且不同种类海草的根际微生物群落无显著差异,不具有物种特异性。  相似文献   

7.
野生型爪蟾的色素基因是显性,a~p白化型的色素基因是隐性。用a~p型精子与野生型卵子受精,以UV照射卵子使卵核失活,再用静液压方法抑制受精卵的第一次核分裂,结果产生雄核发育的二倍体(androgenetic diploid)。它们是核质杂种。这些杂种发育时黑色素细胞出现时期同野生型一致。色素细胞的数目和颜色介于野生型和白化型之间。当白化型蝌蚪本来就极少的色素细胞消退时,杂种蝌蚪仍有许多色素细胞,直至变态完成两个月后色素才完全消退。因此核质杂种黑色素细胞的发育并维持到变态后,归因于野生型卵细胞质对a~p型核的作用。??实验还证明了仅具有父本基因组的爪蟾能发育至成体,性成熟,均为雄性。其精子与正常卵结合产生发育正常的下一代。现已变态成为幼蟾。  相似文献   

8.
[目的]:克隆鳗弧菌flaE基因并分析其蛋白结构,为研究该蛋白的生物学功能及免疫原性奠定基础。[方法]通过PCR方法对鳗弧菌flaE基因进行扩增,利用生物学软件对其序列及蛋白质结构进行分析。[结果]所得flaE基因的大小为841bp,其开放阅读框长度为798 bp,编码262个氨基酸。蛋白分子质量为28 411.4,理论等电点p I为5.70,脂肪系数为81.60,不稳定系数为31.81;为疏水性蛋白;没有信号肽和跨膜螺旋结构;保守区结构域属于flagellin家族;二级结构中以α螺旋为主,其次是无规则卷曲和β片层,少量β转角;三级结构与3k8v.1.A的结构模型相似率为90%。[结论]成功克隆了鳗弧菌flaE基因,Gen Bank登录号为KM091934。  相似文献   

9.
彩色马铃薯富含花色苷,是一种天然抗氧化食品.本研究采用高效液相色谱质谱联用技术以引进品种“黑美人”为对照分析了云南马铃薯地方特色品种“剑川红”和“转心乌”花色苷的主要成分.结果表明:“剑川红”色素主要为酰化天竺葵色素类花色苷,其主要成分为天竺葵素3-[ 6-O-( 4-O-E-p-香豆酰-O-α-吡喃鼠李糖苷)-β-D-吡喃葡萄糖苷]-5-O-β-D-毗喃葡萄糖苷.“转心乌”和“黑美人”所含色素相似,主要为酰化矮牵牛色索、锦葵色素、芍药色素类衍生物,主要成分均为矮牵牛花色素3-[ 6-O-( 4-O-E-p-香豆酰-O-α-吡喃鼠李糖苷)-β-D-毗喃葡萄糖苷]-5-O-β-D-毗喃葡萄糖苷.  相似文献   

10.
系统研究了我国本土两栖动物种黑斑蛙(Rana nigromaculata)变态发育过程中甲状腺组织学和甲状腺激素水平的变化,为甲状腺生物学和甲状腺干扰研究提供基础数据。黑斑蛙蝌蚪发育的形态变化:第26—40阶段,后腿芽生长并逐渐分化出五趾结构;42阶段,开始进入变态高峰期,前肢展开,尾吸收,蝌蚪身体发生巨大形变;46阶段,蝌蚪完全变态成小蛙。随着形态学的变化,甲状腺的组织结构也发生明显的变化:26—37阶段,甲状腺体积较小,增长缓慢;38阶段甲状腺体积迅速膨大,进入高峰期,甲状腺的发育达到顶峰;随着变态完成,甲状腺又逐渐缩小。甲状腺组织学变化的同时,甲状腺激素水平也相应发生变化:在变态前期,下颌中3,3’,5-三碘代-L-甲腺原氨酸(T3)水平增长缓慢,进入变态期后,T3含量迅速升高,在变态高峰期达到峰值,随后下降。以上结果表明,黑斑蛙发育过程中甲状腺组织学的变化与甲状腺激素水平的波动相吻合。对黑斑蛙甲状腺系统的研究,可为日后使用黑斑蛙开展甲状腺干扰作用的研究提供基础。  相似文献   

11.
12.
An identification key for 20 common strand-forming indoor wood decay fungi is given. The key is based on observations of material from affected buildings and on wood samples that have been incubated in the laboratory. The key is with macro- and microscopic photographs.  相似文献   

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14.
Between 1974 and 1978, 2,842 identifications of plant-parasitic nematodes were made from more than 1,700 soil and plant samples collected in eight provinces of South Viet Nam. Species in nine genera—Helicotylenchus, Criconemoides, Meloidogyne, Pratylenchus, Tylenchorhynchus, Hoplolaimus, Hirschmanniella, Xiphinema, and Rotylenchulus—comprised 96.1% of the identifications; the remaining 3.9% were species of 11 genera. Fourteen genera were associated with rice which was grown on about 2,500,000 ha in 1970. Of these, Ditylenchus, Hirschmanniella, and Meloidogyne were most important. Ditylenchus angustus caused severe damage to about 50,000 ha of flooded rice in the Mekong Delta in 1976. Hirschmanniella spp. were found in all samples examined from flooded rice fields. Meloidogyne spp. were common in rice seedbeds, upland rice, and rice not kept flooded continuously. Meloidogyne and Pratylenchus spp. were found in roots of 22 of the 32 crop plants sampled. Little or no attempt was made in South Viet Nam to control nematodes.  相似文献   

15.
Mammals with more rapid and agile locomotion have larger semicircular canals relative to body mass than species that move more slowly. Measurements of semicircular canals in extant mammals with known locomotor behaviours can provide a basis for testing hypotheses about locomotion in fossil primates that is independent of postcranial remains, and a means of reconstructing locomotor behaviour in species known only from cranial material. Semicircular canal radii were measured using ultra high resolution X-ray CT data for 9 stem primates (“plesiadapiforms”; n = 11), 7 adapoids (n = 12), 4 omomyoids (n = 5), and the possible omomyoid Rooneyia viejaensis (n = 1). These were compared with a modern sample (210 species including 91 primates) with known locomotor behaviours. The predicted locomotor agilities for extinct primates generally follow expectations based on known postcrania for those taxa. “Plesiadapiforms” and adapids have relatively small semicircular canals, suggesting they practiced less agile locomotion than other fossil primates in the sample, which is consistent with reconstructions of them as less specialized for leaping. The derived notharctid adapoids (excluding Cantius) and all omomyoids sampled have relatively larger semicircular canals, suggesting that they were more agile, with Microchoerus in particular being reconstructed as having had very jerky locomotion with relatively high magnitude accelerations of the head. Rooneyia viejaensis is reconstructed as having been similarly agile to omomyids and derived notharctid adapoids, which suggests that when postcranial material is found for this species it will exhibit features for some leaping behaviour, or for a locomotor mode requiring a similar degree of agility.  相似文献   

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17.
In this review some emerging issues of parasite infections in wildlife, particularly in Australia, are considered. We discuss the importance of understanding parasite biodiversity in wildlife in terms of conservation, the role of wildlife as reservoirs of parasite infection, and the role of parasites within the broader context of the ecosystem. Using a number of parasite species, the value of undertaking longitudinal surveillance in natural systems using non-invasive sampling and molecular tools to characterise infectious agents is illustrated in terms of wildlife health, parasite biodiversity and ecology.  相似文献   

18.
A phylogenetic analysis of Bambusa and allies based on the plastid DNA non-coding regions rps16-trnQ, trnC-rpoB, trnH-psbA and trnD-T, and a partial nuclear GBSSI gene, was carried out. This included representatives from all four Bambusa subgenera (including type species), a group of segregate Southeast Asian genera distinctive by their climbing–scrambling culms (Dinochloa, Holttumochloa, Kinabaluchloa, Maclurochloa, Soejatmia, Sphaerobambos), and two other Bambusinae genera (Dendrocalamus, Gigantochloa). The results do not support the present subgeneric classification of Bambusa. The climbing Southeast Asian genera, all of which include species previously placed in Bambusa, are distinct from the “core Bambusa group” (type species and alliance) and the Bambusa complex generally.  相似文献   

19.
MicroRNAs are indispensable players in the regulation of a broad range of biological processes. Here, we report the first deep sequencing of the whitespotted bamboo shark (Chiloscyllium plagiosum) liver. We mapped 91 miRNAs in the Callorhinchus milii genome that have previously been described in the Danio rerio, Fugu rubripes, Oryzias latipes, Xenopus laevis, Xenopus tropicalis, Homo sapiens, and Mus musculus. In addition, 156 new putative candidate (PC) C. plagiosum miRNAs were identified. From these 247 miRNAs, 39 miRNA clusters were identified, and the expression of these clustered miRNAs was observed to vary significantly. A total of 7 candidate miRNAs were selected for expression confirmation by stem-loop RT-PCR. This study resulted in the addition of a significant number of novel miRNA sequences to GenBank and laid the foundation for further understanding of the function of miRNAs in the regulation of C. plagiosum liver development.  相似文献   

20.
In eukaryotes, mature rRNA sequences are produced from single large (45S) precursor (pre-rRNA) as the result of successive removal of spacers through a series of rapid and intricate actions of endo- and exonucleases. The excision of internal transcribed spacer (ITS2), a eukaryotic-specific insertion, remains the most elusive processing step. ITS2 is the element mandatory for all eukaryotic pre-rRNAs that contain at least three processing cleavage sites for precise 5.8S and 28S formation. Conserved core sequences (cis-elements) binding to trans-factors provide for precise rRNA processing, whereas rapidly diverging regions between the core sequences preserve internal complementarity, which guarantees the spatial integrity of ITS2. Characteristic differences in the formation of such insertions during evolution should reflect the relationships between taxa. The phylogeny of the reptiles and the relationships between taxa proposed by scientists are controversial. To delineate the structural and functional features preserved among reptilian ITS2s, we cloned and sequenced 58 ITS2s belonging to four reptile orders: Squamata, Crocodilians, Aves, and Testudines. We studied the subsequent alignment and folding of variable regions. The sizes and packing of the loop–stems between conserved consensus segments in reptiles vary considerably between taxa. Our phylogenetic trees constructed on the basis of the reptile ITS2s primary structural alignments revealed a split between Iguania clade and all other taxa. True lizards (suborder Scleroglossa) and snakes (suborder Serpentes) show sister relationships, as well as the two other reptilian orders, Crocodilia + Aves and Testudines. In summary, our phylogenetic trees exhibit a mix of specific features deduced or, to the contrary, rejected earlier by other authors.  相似文献   

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