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1.
雌核发育彭泽鲫子代及双亲组织同工酶的比较研究   总被引:3,自引:1,他引:2  
采用7.5%(ω)聚丙烯酰胺垂直板电泳技术研究了丰产鲫及其母本彭泽鲫和父本尖鳍鲤的心、肝、肾、脑4种组织的苹果酸酶(ME)、超氧化物歧化酶(SOD)和酯酶(EST)同工酶表型以及血清蛋白表型.结果表明:丰产鲫的血清蛋白和3种组织同工酶的电泳图谱均与母本彭泽鲫相同而与父本尖鳍鲤显著不同.说明丰产鲫是彭泽鲫卵子在尖鳍鲤精子激发下的雌核发育后代,在血清蛋白和同工酶表型的水平上,异源父本对子代成体的表型无影响。  相似文献   

2.
运用PCR扩增、克隆、测序等技术,分别获得三倍体鲫鲂、四倍体鲫鲂、五倍体鲫鲂和团头鲂、草鱼、鲢鱼、鳙鱼等鲤科鱼CyclinB基因部分DNA序列.结合异源四倍体鲫鲤及其原始亲本红鲫和鲤鱼CyclinB基因对应DNA序列,对不同倍性鲤科鱼类CyclinB基因DNA片段序列进行比较分析.结果表明:由相同引物扩增的染色体数为48的鲂、草、鲢、鳙鱼,只扩增出1条DNA片段,片段长度分别为750bp,950bp,720bp和720bp,而染色体数目加倍的红鲫、鲤鱼、异源四倍体鲫鲤、异源四倍体鲫鲂,扩增出2条DNA片段(1200bp和900bp),三倍体和五倍体鲫鲂扩增出3条DNA片段(1200bp,900bp和750bp),每个DNA片段均含CyclinB基因第2,3内含子和第2,3,4外显子.序列分析表明,四倍体鲫鲤、三倍体鲫鲂、四倍体鲫鲂和五倍体鲫鲂与其母本1200bp片段同源性分别为99.5%,98.9%,99.5%和88.7%,与母本900bp片段同源性分别为97.5%,94.6%,94.2%和89.99/6,说明四倍体鲫鲤与多倍体鲫鲂1200bp和900bpCyclinB基因片段与母本红鲫同源性高,在进化上具有偏母性遗传特性.而三倍体和五倍体鲫鲂的750bpCyclinB基因片段-9父本同源性分别高达98.6%和98.2%,说明其来自父本团头鲂.在两性可育的异源四倍体鲫鲤和异源四倍体鲫鲂中存在各自父本CyclinB基因片段序列消除现象.此外,用CyclinB基因内含子3序列构建不同倍性鲤科鱼的系统进化树,结果表明,由CyclinB基因内含子序列构建的系统进化树可以正确反映亲缘关系较近的鲤亚科属间鱼类系统进化关系,而不适合亲缘关系较远的亚科间杂交鱼类系统进化分析.  相似文献   

3.
对中国鲿科鱼类系统分类学研究中发现,凹尾拟鲿为一不同于细体拟鲿(P.pratti)的有效种,仅分布于长江上游。凹尾拟鲿胸刺前缘光滑无锯齿,颌须较短,后伸不超过胸鳍起点,本属中同时具有这两个特征的还包括18个有效种。在这18个物种中,乌苏里拟鲿(P.ussuriensis)、长脂拟鲿(P.adiposalis)、短尾拟鲿(P.brevicaudatus)和越南拟鲿(P.kyphus)与凹尾拟鲿一样,具有中等分叉的尾鳍。凹尾拟鲿与乌苏里拟鲿和长脂拟鲿的区别在于游离脊椎骨数目和背刺长短等性状上,与短尾拟鲿和越南拟鲿在背刺后缘程度、枕骨棘与项背骨间的间距上存在差异。凹尾拟鲿与细体拟鲿在形态上最为相似,但在体高、背鳍前长、脂鳍高及尾柄高等性状上存在差别。同时,在颅骨、犁骨、项背骨及腰带等骨骼特征上也存在较大差异。  相似文献   

4.
对中国鲿科鱼类系统分类学研究中发现,凹尾拟鲿为一不同于细体拟鲿(P. pratti)的有效种,仅分布于长江上游。凹尾拟鲿胸刺前缘光滑无锯齿,颌须较短,后伸不超过胸鳍起点,本属中同时具有这两个特征的还包括18个有效种。在这18个物种中,乌苏里拟鲿(P. ussuriensis)、长脂拟鲿(P. adiposalis)、短尾拟鲿(P. brevicaudatus)和越南拟鲿(P. kyphus)与凹尾拟鲿一样,具有中等分叉的尾鳍。凹尾拟鲿与乌苏里拟鲿和长脂拟鲿的区别在于游离脊椎骨数目和背刺长短等性状上,与短尾拟鲿和越南拟鲿在背刺后缘程度、枕骨棘与项背骨间的间距上存在差异。凹尾拟鲿与细体拟鲿在形态上最为相似,但在体高、背鳍前长、脂鳍高及尾柄高等性状上存在差别。同时,在颅骨、犁骨、项背骨及腰带等骨骼特征上也存在较大差异。  相似文献   

5.
在鲫鲤F2(红鲫(♀)×鲤鱼(♂))中,发现8尾双头畸形鱼.对这8尾双头鱼的胚胎发育、外形特征、存活时间及他们的显微结构进行了观察.结果表明:8尾双头鱼的共同特征是具有明显的两个头,两个心脏.其中7尾双头鱼为两个头部,一个身体;另1尾为两个头部,两个身体.组织学切片观察发现双头鱼头部发育正常,其中两对眼睛中可见正常发育的视杯、晶状体、角膜等结构;脑中可见两个明显分界的大脑;两个心脏具有正常的围心腔;腮裂、鳔和肠管等也发育良好.但所有双头鱼在出膜后10天左右开始相继死亡,死亡的原因与随着生长发育进程的进行,两个头部器官在内部生理和外部水环境中都存在相应的困难有关系.此外,鲫鲤F2中多尾双头鱼的形成与它们是属间的远缘杂交后代有关,亲缘关系较远的染色体之间的互作导致基因表达异常,导致出现较高比例的异常胚胎.  相似文献   

6.
对雌雄两性能育并形成群体的异源四倍体鲫鲤的染色体数目和组型,DNA含量,红细胞大小,生殖腺和配子,胚胎发育,形成机理,外形等方面进行了较全面描述。四倍体鲫鲤经过九代(F3-F11)的四倍体性的繁殖,已形成了一个数目庞大的遗传性状稳定的群体。该四倍体群体在染色体数目、生殖、外形特征等方面都与它们的原始父母本-二倍体湘江野鲤和红鲫有本质的差别。在遗传特性、稳定传代、生育隔离等方面,异源四倍体鲫鲤群体为形成一个新的四倍体新种奠定了基础。新的四倍体鱼群体的形成对脊椎动物的进化理论和它们在生产上的应用都具有重要的意义。  相似文献   

7.
运用PCR扩增、克隆、测序等技术,分别获得三倍体鲫鲂、四倍体鲫鲂、五倍体鲫鲂和团头鲂、草鱼、鲢鱼、鳙鱼等鲤科鱼Cyclin B基因部分DNA序列.结合异源四倍体鲫鲤及其原始亲本红鲫和鲤鱼cyclin B基因对应DNA序列,对不同倍性鲤科鱼类cyclin B基因DNA片段序列进行比较分析.结果表明:由相同引物扩增的染色体数为48的鲂、草、鲢、鳙鱼,只扩增出1条DNA片段,片段长度分别为750 bp,950 bp,720 bp和720 bp,而染色体数目加倍的红鲫、鲤鱼、异源四倍体鲫鲤、异源四倍体鲫鲂,扩增出2条DNA片段(1200 bp和900 bp),三倍体和五倍体鲫鲂扩增出3条DNA片段(1200 bp,900 bp和750 bp),每个DNA片段均含Cyclin B基因第2,3内含子和第2,3,4外显子.序列分析表明,四倍体鲫鲤、三倍体鲫鲂、四倍体鲫鲂和五倍体鲫鲂与其母本1200 bp片段同源性分别为99.5%,98.9%,99.5%和88.7%,与母本900 bp片段同源性分别为97.5%,94.6%,94.2%和89.9%,说明四倍体鲫鲤与多倍体鲫鲂1200 bp和900 bpCyclin B基因片段与母本红鲫同源性高,在进化上具有偏母性遗传特性.而三倍体和五倍体鲫鲂的750 bp Cyclin B基因片段与父本同源性分别高达98.6%和98.2%,说明其来自父本团头鲂.在两性可育的异源四倍体鲫鲤和异源四倍体鲫鲂中存在各自父本Cyclin B基因片段序列消除现象.此外,用Cyclin B基因内含子3序列构建不同倍性鲤科鱼的系统进化树,结果表明,由Cyclin B基因内含子序列构建的系统进化树可以正确反映亲缘关系较近的鲤亚科属间鱼类系统进化关系,而不适合亲缘关系较远的亚科间杂交鱼类系统进化分析.  相似文献   

8.
以鱼的尾鳍为材料,采用苯酚—氯仿法提取鱼的基因组DNA.对提取的结果进行紫外分光光度、琼脂糖凝胶电泳方法的鉴定,筛选出浓度、纯度好的DNA样品进行进一步的RAPD扩增.采用上海生化工程有限公司的80个引物对洞庭青鲫和洞庭青鲫(♀)×兴国红鲤(♂)杂交F1代(简称“杂交鱼”)进行RAPD分析,筛选出9个引物对洞庭青鲫和杂交鱼进行了遗传多样性分析,这9个引物共检出洞庭青鲫89个位点、杂交鱼82个位点.其中多态性位点数:洞庭青鲫76个,杂交鱼71个分别占其总位点数的85.39%、86.58%.据RAPDdataanalyzer1.3v.exe数据分析程序计算,洞庭青鲫平均遗传相似度为0.6537;杂交鱼的平均遗传相似度为0.6218;两种群间的为0.5505.上述两项指标的初步分析表明,这两种鱼具有较为丰富的遗传多样性.  相似文献   

9.
1991~ 1998年收治了外伤性小肠破裂 32例 ,男 2 3例 ,女 9例。年龄 5~ 71岁 ,致伤原因以交通事故、建筑坠落及刀刺伤为多。合并伤以脾肝破裂为多。均经单纯肠修补或肠部分切除吻合术 ,并对合并伤进行了治疗。治愈 30例 ,死亡 2例 ,死亡原因均为合并创伤感染性休克 ,导致MODS所致。提出 :1、早期诊断应注意 :①详细询问病史 ,了解暴力的性质、大小、方向、部位及伤后病人的反应。②全面反复仔细的检查腹部压痛及反跳痛部位、范围、程度 ,肝浊音界及移动性浊音以及肠鸣音的变化。③反复多部位的腹穿是简易、准确及理想的诊断方法。④腹部X -线检查及B超探查有助于早期诊断。 2、外伤性小肠破裂一旦确诊应尽早手术治疗 ,其探查指征 :①伤后持续性剧烈腹痛、腹膜炎症状逐渐加重。②腹部开放性肠管外露或肠液外漏。③腹透膈下游离气体。④腹穿阳性。 3、手术要求简单、有效、确实可靠 ,彻底清洗腹腔和有效的引流。 4、肠管切除肠吻合的指征 :①肠管破裂周径 >2 / 3或肠管横断。②短距离内有多处肠管破裂穿孔 ,缝合后有可能发生狭窄梗阻者。③因肠管损伤或肠系膜损伤引起肠管明显血运障碍者。  相似文献   

10.
本文就曹河水库与丹江口水库中鲤的年龄与生长进行了比较研究。鳞片上年轮特征表现为切割与疏密两大标志,特别是第一轮较显著,而高轮的特征主要为切割。两类水体的年轮特征基本一致。环纹间距对鉴定年龄有一定的参考价值。环纹数随年龄增大而增多,在5龄内呈线性相关。年轮形成时期主要为4~6月。鳞径与各种可量性状之间呈一元线性相关。鳞长与体重的关系相似于体长与体重的关系。曹河水库鲤生长明显慢于丹江口水库鲤。  相似文献   

11.
大瑶山国家级自然保护区鱼类群落研究   总被引:1,自引:0,他引:1  
2008年7月-2009年9月对大瑶山自然保护区进行鱼类调查,结果发现大瑶山有鱼类37种,隶属4目13科31属,鲤科鱼类是最大类群,优势种为瑶山鲤(Yaoshanicus arcus)、横纹南鳅(Schistura fasciolata)和溪吻鰕虎鱼(Rhinogobius duospilus).主要为山区溪流性小型鱼类,以杂食性和底栖鱼类为主,底栖鱼类占总数的64.86%.杂食性占43.24%,植物食性占16.21%,动物食性占21.62%,碎屑食性占18.92%.生境丧失和过度捕捞是造成鱼类多样性下降主要原因,提出了保护鱼类资源的建议.  相似文献   

12.
1140 bp of cytochrome b gene were amplified and sequenced from 14 species of primitive cyprinid fishes in East Asia. Aligned with other ten cytochrome b gene sequences of cyprinid fish from Europe and North America retrieved from Gene bank, we obtained a matrix of 24 DNA sequences. A cladogram was generated by the method of Maximum likelihood for the primitive cyprinid fishes. The result indicated that subfamily Leuciscinae and Danioninae do not form a monophyletic group. In the subfamily Danioninae, Opsariichthys biden and Zacco platypus are very primitive and form a natural group and located at the root. But the genera in subfamily Danioninae are included in different groups and have not direct relationship. Among them, Aphyocypris chinensis and Yaoshanicus arcus form a monophyletic group. Tanichthys albonubes and Gobiocypris rarus have a close relation to Gobioninae. The genus Danio is far from other genera in Danioninae. In our cladogram, the genera in Leuciscinae were divided into two groups that have no direct relationship. The genera in Leuciscinae distributed in Europe, Sibera and North America, including Leuciscus, Rutilus, Phoxinus, N. crysole, Opsopoeodus emilae, form a monophyletic group. And the Leuciscinae in southern China including Ctenopharyngodon idettus, Mylopharyngodon piceus, Squalibarbus and Ochetobius elongatus have a common origination.  相似文献   

13.
Sunspot umbrae--the dark central regions of the spots--are surrounded by brighter filamentary penumbrae, the existence of which remains largely inexplicable. The penumbral filaments contain magnetic fields with varying inclinations and are associated with flowing gas, but discriminating between theoretical models has been difficult because the structure of the filaments has not hitherto been resolved. Here we report observations of penumbral filaments that reveal dark cores inside them. We cannot determine the nature of these dark cores, but their very existence provides a crucial test for any model of penumbrae. Our images also reveal other very small structures, in line with the view that many of the fundamental physical processes in the solar photosphere occur on scales smaller than 100 km.  相似文献   

14.
论述了直接在明室中动态测量瞳孔测试仪的研制.采用近红外摄象、瞳孔视频信号处理、电子窗口等技术分析瞳孔视频信号的处理,保证动态瞳孔测试仪能够在明室或暗室中测量瞳孔的直径和面积.此外,在个别受试者的眼皮遮去部份瞳孔时,该测试仪也能进行正确测量.  相似文献   

15.
暗能量的射电探测——天籁计划简介   总被引:1,自引:0,他引:1  
宇宙中的中性氢原子产生波长为21cm的辐射,其强度在大尺度上正比于物质密度.通过射电观测这一辐射,可以获得宇宙中物质分布的大尺度结构.利用大尺度结构功率谱中的重子声波振荡信号作为标准尺,可以进行高精度的宇宙学测量,确定暗能量状态方程参数w,这提供了一种重要的暗能量观测手段.我国在射电天文及相关技术方面有一定基础,且国内即有电磁环境良好的站址,有很好的条件开展这方面的研究.如能及时着手,有可能在这一领域中取得领先,并在暗能量研究中取得突破.本文介绍了通过21cm巡天对暗能量进行观测的方法,并讨论了天籁计划具体实验设想.  相似文献   

16.
Mashchenko S  Couchman HM  Wadsley J 《Nature》2006,442(7102):539-542
The standard cosmological model, now strongly constrained by direct observations of the Universe at early epochs, is very successful in describing the evolution of structure on large and intermediate scales. Unfortunately, serious contradictions remain on smaller, galactic scales. Among the main small-scale problems is a significant and persistent discrepancy between observations of nearby galaxies, which imply that galactic dark matter haloes have a density profile with a flat core, and the cosmological model, which predicts that the haloes should have divergent density (a cusp) at the centre. Here we report numerical simulations that show that random bulk motions of gas in small primordial galaxies, of the magnitude expected in these systems, will result in a flattening of the central dark matter cusp on relatively short timescales (approximately 10(8) years). Gas bulk motions in early galaxies are driven by supernova explosions that result from ongoing star formation. Our mechanism is general, and would have operated in all star-forming galaxies at redshifts z > or = 10. Once removed, the cusp cannot be reintroduced during the subsequent mergers involved in the build-up of larger galaxies. As a consequence, in the present Universe both small and large galaxies would have flat dark matter core density profiles, in agreement with observations.  相似文献   

17.
南方鲶脑和脑神经的观察   总被引:5,自引:1,他引:5  
对南方鲶脑的外部形态和内部结构及脑神经特点进行了描述.与一般鲤科鱼类的脑比较其不同点在于:端脑发达,体积比视叶大;小脑特别发达,向前盖住中脑、间脑和部分端脑,后部向两侧扩展成耳状叶;间脑有明显的中间叶、球状核,视交叉紧靠间脑前方,脑下垂体在二下叶之间,远离视神经交叉.并具有特别的副侧线神经、侧线神经侧腹支及电觉初级中枢.靠味觉和嗅觉共同摄取食物.  相似文献   

18.
在简述多尺度科学的主要研究内容、方法及现状的基础上,从多尺度科学角度出发,提出了油气藏即是一个复杂的多尺度系统,油气产出是一个跨时间和空间尺度的复杂过程,是在微观孔喉、微裂缝至宏观裂缝、水力裂缝等渗流通道中的一系列串联耦合过程的观点。油气田开发中多尺度问题主要包括油气藏多尺度描述、多尺度数据整合以及多尺度模拟。以致密砂岩气藏为例,探讨了非常规天然气开发中的多尺度现象及其对气藏开发的影响及对策。指出致密砂岩气藏多尺度结构由基块孔喉、天然裂缝和水力裂缝组成,基块供气不足和储层损害是制约气井产能的关键因素。基于多尺度传质理论大幅度提高传质效率,强调加强钻井、完井和增产改造等全过程储层保护、采用最大储层接触面积(MRC)技术是开发非常规油气资源的有效途径。  相似文献   

19.
Luminet JP  Weeks JR  Riazuelo A  Lehoucq R  Uzan JP 《Nature》2003,425(6958):593-595
The current 'standard model' of cosmology posits an infinite flat universe forever expanding under the pressure of dark energy. First-year data from the Wilkinson Microwave Anisotropy Probe (WMAP) confirm this model to spectacular precision on all but the largest scales. Temperature correlations across the microwave sky match expectations on angular scales narrower than 60 degrees but, contrary to predictions, vanish on scales wider than 60 degrees. Several explanations have been proposed. One natural approach questions the underlying geometry of space--namely, its curvature and topology. In an infinite flat space, waves from the Big Bang would fill the universe on all length scales. The observed lack of temperature correlations on scales beyond 60 degrees means that the broadest waves are missing, perhaps because space itself is not big enough to support them. Here we present a simple geometrical model of a finite space--the Poincaré dodecahedral space--which accounts for WMAP's observations with no fine-tuning required. The predicted density is Omega(0) approximately 1.013 > 1, and the model also predicts temperature correlations in matching circles on the sky.  相似文献   

20.
Most of the matter in the Universe is not luminous, and can be observed only through its gravitational influence on the appearance of luminous matter. Weak gravitational lensing is a technique that uses the distortions of the images of distant galaxies as a tracer of dark matter: such distortions are induced as the light passes through large-scale distributions of dark matter in the foreground. The patterns of the induced distortions reflect the density of mass along the line of sight and its distribution, and the resulting 'cosmic shear' can be used to distinguish between alternative cosmologies. But previous attempts to measure this effect have been inconclusive. Here we report the detection of cosmic shear on angular scales of up to half a degree using 145,000 galaxies and along three separate lines of sight. We find that the dark matter is distributed in a manner consistent with either an open universe, or a flat universe that is dominated by a cosmological constant. Our results are inconsistent with the standard cold-dark-matter model.  相似文献   

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