x,i(xq)—x染色体长臂等臂一例

刘X,女,14岁。因生长发育迟缓就诊。患 者是第3胎足月顺产,2岁始会走路及说简单 话语,7岁上小学,二年级时因全部课程不及 格,被迫退学。患者生后即生长发育缓慢,现可 从事一般家务劳动,无月经来潮。母孕期未接 触有害物质,无流产史,家族中无类似患者     

Polyphyletic allopolyploid origin ofRanunculus cantoniensis (4x) fromR. silerifolius (2x) ×R. chinensis (2x)

Both diploid and tetraploid experimental interspecific hybrids betweenRanunculus silerifolius (2x) andR. chinensis (2x) exhibit normal bivalent pairing. However, microspores of diploid hybrids do not undergo mitosis and their pollen grains are highly sterile, whereas tetraploid hybrids form good pollen grains after microspore division. Evidence is forwarded for the assumption thatR. cantoniensis (4x) has originated by hybridization between these two diploid parental species and by polyploidization of the diploid hybrids. Parallelisms between the different karyotypes ofR. cantoniensis (4x) andR. silerifolius (2x) suggest that the former is a species of polyphyletic origin.     

Cytological and breeding behavior of pentaploids derived from 3x × 4x crosses in potato

Cytology and breeding behavior of Solanum commersonii - S. tuberosum hybrids derived from 3 x x 4 x crosses was examined. The chromosome number of hybrids ranged from hypo-pentaploid (2 n=5 x - 8=52), to hyper-pentaploid (2 n=5 x + 7=67), with the euploid pentaploid 2 n=5 x=60 class predominant. The high variability in chromosome number of the 3 x x 4 x hybrids was attributed to the fact that meiotic restitution during megasporogenesis of the 3 x female may have involved poles with various chromosome numbers, resulting in 2 n eggs with 24-48 chromosomes. Microsporogenesis analyses provided evidence that chromosome pairing between S. commersonii and S. tuberosum genomes occurred. In addition, chromosome distribution at anaphase I and anaphase II revealed an average chromosome number of 29.5 and 29.1 per pole, respectively. To further study the extent of transmission of extra genome chromosomes from pentaploids, 5 x x 4 x and 4 x x 5 x crosses were performed, and the chromosome number of resulting progeny was determined. Ploidy ranged from 2 n=4 x=48 to 2 n=5 x=60 following 5 x x 4 x crosses, and from 2 n=4 x + 1=49 to 2 n=5 x=60 following 4 x x 5 x crosses. These results provided indirect evidence that the pentaploid hybrids produced viable aneuploid gametes with a chromosome number ranging from 24 to 36. They also demonstrated that gametes with large numbers of extra chromosomes can be functional, resulting in sporophytes between the 4 x and 5 x ploidy level. Fertility parameters of crosses involving various (aneuploid) pentaploid genotypes were not influenced by chromosome number, suggesting a buffering effect of polyploidy on aneuploidy. The possibility of successfully using (aneuploid) pentaploid genotypes for further breeding efforts is discussed.     

Fertilization fitness and offspring ploidy in 3x × 2x matings in potato

Abstract

The main objective of the current research was to study the reproductive behaviour of artificial triploid potato hybrids between wild Solanum commersonii and the cultivated potato Solanum tuberosum. When used in 3x × 2x crosses, triploids gave aneuploid progenies with somatic chromosome number ranging from 29 to 36. Fertilization fitness data suggested that the survival rate of gametes produced by the triploid parents may be related to their chromosome number. In addition, consistent with molecular data, our results indicated that fitness of gametes and chromosome number of progenies are influenced by the genome dosage of interspecific triploids. Since a main route to polyploidy formation is via 2n gametes and triploids, our study may contribute to a better understanding of polyploid plant reproduction, evolution and breeding.     

琥珀酸脱氢酶的x光光谱研究

使用同步辐射光源,以荧光模式研究了琥珀脱氢酶的X光吸收光谱,表明所含的铁硫蛋白中,铁处于硫的四面体配位中;由氧化态及还原态的铁K边化学位移大小可知每个铁原子得失电子个数,SDHu(A)为0.39,,SDH(I)为0.30,,都比1小得多;表明有配位体容纳电子的作用,也表明有重组活性的SDH(A),具有较强的接受电子能力.文中引用量子化学计算结果对光谱现象予以合理的解释.     

胸部急性创伤的x线诊断

目的：探讨X线对胸部急性创伤的诊断价值及特征,提高对胸部创伤的诊断。方法：回顾分析160例胸部急性创伤的临床病例资料,对X线表现进行分析和讨论。结果：胸部创伤X线上有多种表现,其中肺部渗出性病变61．25％（98／160）,肺血肿3．75％（6／160）,肺囊肿2．5％（4／160）,肺不张2．5％（4／160）,血气胸52．5％（84／160）,气胸31．25％（50／160）,纵隔及皮下气肿40％（64／160）,创伤性隔疝2．5％（4／160）,肋骨骨折86．25％（138／160）。结论：胸部急性创伤的X线表现多种多样,但均具有一定的特征性X线表现,伤后连续的X线复查并紧密结合临床,有助于提高诊断的准确性。     

DNA聚合酶x家族的系统发育分析

随着DNA聚合酶x家族成员数量的增加,家族内部的系统发育需要重新检查,来自病毒和细胞的DNA聚合酶x家族成员顺序第一次被汇编在一起,进行系统发育分析。分析显示：真核生物DNA聚合酶beta(polβ)可能起源于病毒基因的水平转移;DNA聚合酶mu(polμ)基因仅存在于哺乳动物基因中,是脱氧核苷酸末端转移酶（TdT）的重复基因;DNA聚合酶lambda(polλ)可能是polμ和TdT的祖先基因,但在某些物种的进化过程中发生了基因丢失。     

4x菜心×2x芥蓝的胚胎发育观察及离体培养获得异源三倍体

对4x菜心×2x芥蓝和4x芥蓝×2x菜心的授粉受精及胚胎发育进行了观察,并对其杂种幼胚进行了离体培养.结果表明,4x菜心×2x芥蓝和4x芥蓝×2x菜心的授粉受精均能完成,但胚胎发育受阻,前者在授粉后11d左右(球形胚时期)胚胎败育,后者在授粉后5d左右(几个细胞的原胚时期)胚囊便干缩坏死. 经子房离体培养,4x菜心×2x芥蓝获得了杂种植株,适宜的培养时期是授粉后6～8d,而4x芥蓝×2x菜心未能培养成功.经形态学观察和核型分析,杂种植株在花色、花大小等方面具双亲特征,染色体数为2n=3x=29,含有菜心的2个染色体组(AA)和芥蓝的1个染色体组(C),为异源三倍体(AAC).     

Implementation of extensive citrus triploid breeding programs based on 4x?×?2x sexual hybridisations

Seedlessness is one of the most important characteristics for mandarins for the fresh-fruit market, and mandarin triploid hybrids have this trait. Triploid citrus plants can be recovered by 4x?×?2x hybridisations using non-apomictic genotypes as female parents. In this study, we characterise the type of seeds obtained in 4x?×?2x hybridisations and the ploidy level of plants recovered from each type of seed. The majority of the plants recover were triploid (98.3?%), but a few diploid, tetraploid and pentaploid plants were also produced and their genetic origin was analysed by simple sequence repeat (SSR) markers. We also analysed the influence of parents and environmental conditions on the efficiency of recovery triploid hybrids. In this work, we present an effective methodology to recover triploid hybrids from 4x?×?2x hybridisations based on in vitro embryo rescue and determination of ploidy level by flow cytometry that allow us to recover more than 4,400 triploid hybrids from more than 60 parental combinations.     

Cytology and morphology of the amphiploid Hordeum chilense (4x) × Aegilops squarrosa (4x)

Summary The intergeneric amphiploid Hordeum chilense × Aegilops squarrosa has been synthesized. The amphiploid plants have the expected chromosome number of 28. The average meiotic chromosome pairing was 12.48 bivalents + 3.04 univalents. The morphology of the amphiploid resembles that of the Aegilops parent. Nucleoli from both H. chilense and A. squarrosa are expressed in the amphiploid. Neither chromosome instability nor homoeologous pairing was found. The amphiploid is fertile and vigorous.     

sLea/x与肿瘤血源性转移研究进展

肿瘤细胞表面sLea/x的表达水平与组织病理学参数正相关,且是转移性疾病的一个很重要的预后指标[1]。ssLea/x与其配体E-选择素的结合启动了肿瘤血源性转移的发生。sLea/x与其配体的相互作用需要一定的活性构象,而基于模拟sLea/x的生物活性结构而设计的一类小分子化合物,可以有效地抑制sLea/x与其配体的结合,从而发挥抗肿瘤作用。本论文对近年来sLea/x与肿瘤血源性转移关系的研究及相关药物开发进行了综述。     

45，X/46，X，idic（x）/47，x，idic（X），id（x）嵌合体核型的研究

最常见的人类x染色体的结构异常是长臂 等臂X染色体,以及X染色体与常染色体之间 的易位。关于idic(X）染色体结构异常的病例 较为罕见。国外Chapell：等曾有研究1,国内 周氏等w首次报道了有关idic(X）染色体结构 异常的病例。 1983年我们在一例Turner综合征发现其 外周血淋巴细胞核型具有双着丝粒X染色体, 为45,X/46,X, idic(X)/47,x, idic(X),idic (X）嵌合体核型,现报告如下     

乙肝病毒x基因致肝细胞癌机理探讨

构建HBx基因真核表达载体, 导入HepG2细胞中, 无血清培养同步化后, Western 杂交检测HepG2-X细胞IGF-ⅠR, PCNA和VEGF表达增强, 但无p21CIP1/WAF1表达. 流式细胞检测细胞周期, HepG-X0细胞70%进入G0～G1期, 而HepG2-X细胞仅56%进入G0～G1期, 与血清培养亲本HepG2细胞几乎相同. HBx基因增强IGF-ⅠR表达, 通过信号通路到细胞核, 同时使PCNA表达增强, p21CIP1/WAF1表达抑制, 推进细胞周期, 使G0～G1细胞明显减少. HBx基因增强VEGF表达, 通过旁分泌作用使血管内皮增生; 以上可能是HBx蛋白致HCC 的机理之一.     

The ruminant parasite Haemonchus contortus expresses an α1,3-fucosyltransferase capable of synthesizing the Lewis x and sialyl Lewis x antigens

Glycoproteins from the ruminant helminthic parasite Haemonchus contortus react with Lotus tetragonolobus agglutinin and Wisteria floribunda agglutinin, which are plant lectins that recognize α1,3-fucosylated GlcNAc and terminal β-GalNAc residues, respectively. However, parasite glycoconjugates are not reactive with Ricinus communis agglutinin, which binds to terminal β-Gal, and the glycoconjugates lack the Lewis x (Lex) antigen or other related fucose-containing antigens, such as sialylated Lex, Lea, Leb Ley, or H-type 1. Direct assays of parasite extracts demonstrate the presence of an α1,3-fucosyltransferase (α1,3FT) and β1,4-N-acetylgalactosaminyltransferase (β1,4GalNAcT), but not β1,4-galactosyltransferase. The H. contortus α1,3FT can fucosylate GlcNAc residues in both lacto-N-neotetraose (LNnT) Galα1→4GlcNAcβ1→3Galβ1→4Glc to form lacto-N-fucopentaose III Galβ1→ 4[Fucα1→3]GlcNAcβ1→3Galβ1→4Glc, which contains the Lex antigen, and the acceptor lacdiNAc (LDN) GalNAcβ1→4GlcNAc to form GalNAcβ1→4[Fucα1 →3]GlcNAc. The α1,3FT activity towards LNnT is dependent on time, protein, and GDP-Fuc concentration with a Km 50 μ M and a Vmax of 10.8 nmol-mg?1 h?1. The enzyme is unusually resistant to inhibition by the sulfhydryl-modifying reagent N-ethylmaleimide. The α1,3FT acts best with type-2 glycan acceptors (Galβ1→4GlcNAcβ1-R) and can use both sialylated and non-sialylated acceptors. Thus, although in vitro the H. contortus α1,3FT can synthesize the Lex antigen, in vivo the enzyme may instead participate in synthesis of fucosylated LDN or related structures, as found in other helminths.     

医用诊断x射线发生装置辐射输出量线性

国家医用X射线产品质量监督检验测试中心王寿民工程师撰文“浅谈医用诊断X射线发生装置的照射量线性”,刊登在《医用放射技术杂志》1988年第一期上,该文详述了医用诊断X射线机的三个参数:管电压(KV)、管电流(mA)和曝光时间(Sec)之间的关系、测试方法以及如何选取测试条件等,为便于理解,本文对X射线发生装置输出量线性的问题,作出概述,并引举一个实例供参考。     

应是“腊(xī)叶标本”

蜡,读 qù,为“蛆”的古字;读 zhà或 chà,为古代年终祭名;读 là,主要是指某些动植物分泌的酯类物质。在中学植物学课本有蜡叶标本之说。用植物枝叶压制而成的干标本,既非蜡做,又未涂蜡,何谓“蜡”叶标本?腊,原是一个繁体汉字,读 xī,指干肉,也     

Weevil x Insecticide: Does ‘Personality’ Matter?

An insect’s behavior is the expression of its integrated physiology in response to external and internal stimuli, turning insect behavior into a potential determinant of insecticide exposure. Behavioral traits may therefore influence insecticide efficacy against insects, compromising the validity of standard bioassays of insecticide activity, which are fundamentally based on lethality alone. By extension, insect ‘personality’ (i.e., an individual’s integrated set of behavioral tendencies that is inferred from multiple empirical measures) may also be an important determinant of insecticide exposure and activity. This has yet to be considered because the behavioral studies involving insects and insecticides focus on populations rather than on individuals. Even among studies of animal ‘personality’, the relative contributions of individual and population variation are usually neglected. Here, we assessed behavioral traits (within the categories: activity, boldness/shyness, and exploration/avoidance) of individuals from 15 populations of the maize weevil (Sitophilus zeamais), an important stored-grain pest with serious problems of insecticide resistance, and correlated the behavioral responses with the activity of the insecticide deltamethrin. This analysis was performed at both the population and individual levels. There was significant variation in weevil ‘personality’ among individuals and populations, but variation among individuals within populations accounted for most of the observed variation (92.57%). This result emphasizes the importance of individual variation in behavioral and ‘personality’ studies. When the behavioral traits assessed were correlated with median lethal time (LT₅₀) at the population level and with the survival time under insecticide exposure, activity traits, particularly the distance walked, significantly increased survival time. Therefore, behavioral traits are important components of insecticide efficacy, and individual variation should be considered in such studies. This is so because population differences provided only crude approximation of the individual personality in a restrained experimental setting likely to restrict individual behavior favoring the transposition of the individual variation to the population.