Chara zeylanica Wildenow（现生轮藻）藏卵器几个特征的统计分析

本文对采自广西涠洲岛的现生轮藻Ｃｈａｒａ ｚｅｙｌａｎｉｃａ藏卵器的几个特征作了统计分析,结果表明,藏卵器的最大长度,最大宽度和螺旋环数等性状的变异有一定范围,服从统计规律,单变量的变化呈正态分布,具一明显峰值;ＬＰＡ是ＬＥＤ的线性函数,呈正相关。藏卵器乌黑细胞的钙化程度与成熟度有关。未成熟藏卵器的顶部构造为典型的轮藻型,成熟藏卵的顶部构造与有盖轮藻型接近。因此认为,Ｃｒａｍｂａｓｔｉｃｈａｒａ     

MEIOSIS IN THE OOMYCETES: I. A MICROSPECTROPHOTOMETRIC ANALYSIS OF NUCLEAR DEOXYRIBONUCLEIC ACID IN SAPROLEGNIA TERRESTRIS

A cytological and cytochemical examination of Saprolegnia terrestris Cookson was undertaken to resolve the conflict of opinion regarding the life cycle of fungi in the Saprolegniaceae, i.e., whether meiosis is zygotic or gametic. Microspectrophotometric analysis reveals that pre-divisional oogonial and antheridial nuclei are 4C; a subsequent reduction division in the sex organs produces 1C male and female gametes. These division products coexist in the developing oospore and presumably fuse to produce the diploid zygote. Analysis of the somatic hyphal nuclei shows a 2C DNA content, with the characteristic skew and bimodal character indicative of predominantly G1, and some S-period and G2 types. The evidence is completely consistent with gametic meiosis, i.e., a predominant diploid vegetative phase and short haploid phase, and refutes the notion of zygotic meiosis. Further ramifications of the work are discussed along with preliminary results of related work in progress.     

A POPULATION STUDY OF CHARA ZEYLANICA IN TEXAS,OKLAHOMA, AND NEW MEXICO

Examination of 140 collections of Chara zeylanica from 3 southwestern states shows that a strong dichotomy exists in the collections. Some produce 4-plated antheridia while others produce 8-plated antheridia. Absolute separation of the study material is possible on the basis of plate number. In addition, 3 other characters (length/width ratio of oospores; fertility of first branchlet node; and number of distal ecorticate branchlet internodes) show strong correlation with the antheridial type. Preliminary chromosomal work indicates that a segregation at this level may also be possible. In 4-plated collections examined, n = 28; 8-plated collections are usually n = 56; however, a few 8-plated collections are n = 42. No conclusion has been reached regarding the status of the latter collections.     

木耳属真菌rDNA特异性扩增片段的RFLP研究*

对木耳属8个种25个菌株的ITS和28SrDNA5’端两个区域分别进行了PCR扩增和限制酶切片段长度多态性（RFLP）研究。ITS－RFMP研究结果表明,HaeⅢ可将黑木耳与其它种区分开,MspⅠ可将盾形木耳、角质木耳、琥珀木耳和黑木耳4个种区分开,而供试的HaeⅢ、TaqⅠ、HinfⅠ和MaPⅠ这四种限制酶均不能将皱木耳、大木耳、网脉木耳及毛木耳4个种区分开,表明它们之间的亲缘关系较近;结果还表明,ITS—rDNA拷贝在毛木耳和琥珀木耳种内是异质性的,而在黑木耳种内是同质性的。285rDNA-RFLP研究结果表明,供试的4种限制酶中,仅MspⅠ可将盾形木耳和角质木耳区分开,而不能将其它种区分开,这显示了28SrDNA序列在木耳属不同种间的保守性。     

木耳属真菌rDNA特异性扩增片段的RFLP研究

对木耳属8个种25个菌株的ITS和28SrDNA5’端两个区域分别进行了PCR扩增和限制酶切片段长度多态性（RFLP）研究。ITS－RFMP研究结果表明,HaeⅢ可将黑木耳与其它种区分开,MspⅠ可将盾形木耳、角质木耳、琥珀木耳和黑木耳4个种区分开,而供试的HaeⅢ、TaqⅠ、HinfⅠ和MaPⅠ这四种限制酶均不能将皱木耳、大木耳、网脉木耳及毛木耳4个种区分开,表明它们之间的亲缘关系较近;结果还表明,ITS—rDNA拷贝在毛木耳和琥珀木耳种内是异质性的,而在黑木耳种内是同质性的。285rDNA-RFLP研究结果表明,供试的4种限制酶中,仅MspⅠ可将盾形木耳和角质木耳区分开,而不能将其它种区分开,这显示了28SrDNA序列在木耳属不同种间的保守性。     

膀胱肿瘤DNA含量、核形态学特点与AgNORs计数的研究

应用图像分析技术对４３例膀胱肿瘤细胞ＤＮＡ含量和核形态参数进行了定量测定,同时进行核仁组成区（ＡｇＮＯＲｓ）计数研究,结果表明：肿瘤细胞的ＤＮＡ含量及干系水平与组织学分级基本一致,ＤＮＡ含量及干系水平越高,则恶性程度越高,ＤＮＡ含量与核面积及核最短直径的变化里正相关性,与ＡｇＮＯＲｓ的计数无明显相关性。这三项检测方法对肿瘤生物学行为判断均有重要的参考价值。     

侧耳属核rDNA转录间区扩增产物的限制性酶切分析

对侧耳属18个形态种52个菌株和蘑菇属、香菇属、亚侧耳属各1个菌株的核糖体DNA转录间区进行PCR特异性扩增后,用7种限制性内切酶进行酶切分析。结果表明,BamHⅠ对所有的菌株均无酶切位点;AluⅠ, Hae Ⅲ,HinfⅠ, TaqⅠ, HhaⅠ, MspⅠ可分别将52个菌株分为6, 5, 5, 4, 2, 2组,且可将金顶侧耳与其它侧耳区分开。基于限制性酶切多态性构建的聚类图表明,在93%相似水平,可将所有的侧耳分为七组,第一组:糙皮侧耳、佛罗里达侧耳、美味侧耳、裂皮侧耳、黄白侧耳、哥伦比亚侧耳、灰白侧耳、白阿魏蘑、阿魏蘑及一些未定名的侧耳;第二组:刺芹侧耳;第三组:肺形侧耳和凤尾菇;第四组:具核侧耳;第五组:鲍鱼菇和囊盖侧耳;第六组:红平菇和桃红侧耳;第七组:金顶侧耳。聚类图结果进一步表明,金顶侧耳与其它侧耳的关系较双孢蘑菇和香菇与其它侧耳的关系要远。     

REQUIREMENT OF AN INTERNAL STANDARD FOR MICROSPECTROPHOTOMETRIC MEASUREMENTS OF DNA

Cytophotometric measurements of DNA quantity per cell from 45 different Pinus rigida trees obtained from 135 slides showed that an internal standard was necessary in order to avoid serious errors. Chicken red blood cells were incorporated on the same slide as the pine cells, permitting the calculation of the actual mass units of DNA per pine nucleus. The use of these units makes the results of different investigations and investigators directly comparable. Staining variation between slides and staining batches was shown to be the reason for the requirement of an internal standard. DNA quantity in Feulgen units varied as much as 2.9 fold between different slides of red blood cells although the actual quantity of DNA is constant at 2.8 picograms per nucleus.     

NUCLEAR DNA CONTENT IN POPULATIONS OF PINUS RIGIDA

Five populations of Pinus rigida growing in contrasting ecological situations ranging from North Carolina (35°53'N latitude) to Quebec (45°06'N latitude) showed no significant variation in amounts of nuclear DNA with respect to germinating seedlings. Nuclear volume of dormant nuclei also showed no significant variation between and within populations, a finding that is consistent with the concept that the basic 2C DNA value of Pinus rigida is uniform under all habitats. This finding is in contrast to numerous reports for other coniferous species.     

THE LIFE HISTORY OF COLEOCHAETE SCUTATA (CHLOROPHYCEAE) STUDIED BY A FEULGEN MICROSPECTROPHOTOMETRIC ANALYSIS OF THE DNA CYCLE1,2

The life history of Coleochaete scutata Bréb. was analyzed by Feulgen microspectrophotometry, a technique measuring DNA content in individual nuclei. By correlating nuclear DNA content with morphological structures or stages in the life history, changes in ploidy level are revealed. The microspectrophotometric study confirmed the earlier reports of a haploid vegetative thallus with mitotic division restricted primarily to the margin of the thallus. In the mitotic cycle the G₁ (pre-synthesis) phase is longer in duration than the synthesis find G₂ (post-synthesis) phases. Oogamous sexual reproduction results in resistant oospores which attain DNA levels of 2C 8C (1C being the DNA level of gamete nuclei).     

野生大豆和烟草根尖细胞分化过程中的DNA动态和细胞图像分析

分别截取野生大豆根尖分生区、伸长区和成熟区细胞,用Ｈｏｅｃｈｓｔ３３２５８对ＤＮＡ进行专一染邑,通过计算机数字图象处理系统,采用灰度测量法原位测定根尖不同区的ＤＮＡ含量。同理取烟草根尖不同区细胞,用率尔根反应对ＤＮＡ进行专一染色,并由与扫描显微光度计相联的数字图象处理系统原位测定备区域中细胞的ＤＮＡ含量。发现从分生区到成熟区,细胞核ＤＮＡ含量呈递增趋势。分化的细胞中含量异常增高而不分裂,说明ＤＮＡ的动态变化与发育和分化存在着某种联系。细胞图象分析的结果表明三个区的细胞面积、最大径、最小径及形态因子也沿分生区到成熟区呈递增趋势。     

MICROSPECTROPHOTOMETRIC INVESTIGATIONS OF FREE SPACE IN PLANT CELL WALLS

Two equations were proposed for the determination of free space in plant cell walls. Solution of the equations required microspectrophotometric measurements of cell walls after introduction of a chromophore. A periodic acid-Schiff test was developed for this purpose and a statistical analysis of the error terms was used to evaluate the discriminatory capacity of the system. Bouguer's law was tested directly and found to hold for the tissue thicknesses and wavelengths used. Because concentration was unknown, Beer's law could not be tested directly, but a new method based on the logarithmic transformation of the optical densities and statistical correlation of curve shape was used to predict the wavelength interval in which Beer's law held. Calculations by a newly derived extinction-ratio equation (AE/E) were essentially invariant over the predicted range and variable outside of this wavelength interval. Free space in hydrated S₂ layers of tracheid cell walls of Pinus resinosa Ait. was calculated to be about 25%. The magnitude of free space at various stages of hydration was also tabulated. Considerable free space was found to exist in plant cell walls after prolonged exposure to anhydrous ethyl alcohol; however, after complete dehydration there was little evidence of residual free space.     

QUANTITATIVE VARIATIONS OF NUCLEAR DNA DURING PLANT DEVELOPMENT: A CRITICAL ANALYSIS

In this review a critical analysis is made of the quantitative DNA variations that take place during plant development. These include underreplication, loss and amplification of repeated sequences; particular attention is devoted to quantitative variations of non-coding DNA sequences. Examples reported in the literature are analysed in relation to the different biological phenomena they accompany such as vegetative development, phase changes, senescence, dedifferentiation or tumour formation. The author also considers the influence that external elements such as growth factors, chemical substances, culture medium composition, or, also, different stimuli of environmental character, can have on these quantitative variations of nuclear DNA sequences. Finally the different hypotheses on the role that repetitive DNA sequences (particularly those that are highly repeated) can have on the life of the cell are analysed and discussed. The experimental evidence, although fragmentary and sometimes contradictory, leads to the conclusion that the plant genome is not so ‘quantitatively static’ as was once hought, but is instead characterized by a dynamic plasticity; the role of repeated DNA sequences in the plant development seems to be much more active, than the role hypothesized by many authors in the past.     

ANALYSIS OF NUCLEAR MUTANTS OF CHLAMYDOMONAS DEFICIENT IN THE ACCUMULATION OF SPECIFIC CHLOROPLAST RNAS

Bioluminescence is broadly distributed in marine dinoflagellates and has been intensively studied in Lingulodinium ( Gonyaulax ) polyedra. In this species, bioluminescence is regulated in a circadian fashion; the enzyme (luciferase) and the luciferin (substrate)-binding protein are synthesized and degraded on a daily basis. Synthesis of both proteins is regulated at the level of translation. The L. polyedra luciferase gene is composed of three contiguous domains that are greater than 75% identical at the nucleic acid level. Possible explanations for the high degree of sequence conservation include: (1) the domains evolved through a recent duplication event; (2) the sequence similarity is maintained by a molecular process such as gene conversion; or (3) there is a functional role associated with the primary nucleic acid sequence, such as in the translational regulation of luciferase expression. The phylogenetic relationship of dinoflagellates predicted from 18S rDNA genes provides a framework for examining the molecular evolution of the regulation of luciferase expression and of genes encoding luciferase and the luciferin-binding protein. In particular, we are examining the evolution of the circadian rhythm of bioluminescence and of luciferase abundance, the presence/absence of the luciferin-binding protein, and the molecular structure of the luciferase gene. We anticipate that this approach will distinguish between regions of the luciferase molecule that are conserved for enzyme function versus those concerned with the regulation of protein expression. In addition, it will provide insight into the evolution of the regulatory processes and pathways.     

FLOW-CYTOMETRIC ANALYSES OF NUCLEAR DNA CONTENT IN FOUR FAMILIES OF NEOTROPICAL BATS

Flow-cytometric analyses of 29 species of microchiropteran bats representing four families and 20 genera revealed that bats possess only 79% (5.43 pg) of the DNA content of a “typical” mammal (e.g., Mus musculus strain C57BL; 7 pg). Chiroptera, the second largest order of mammals, is thus an exception to the prevailing view that mammals possess a minimum nuclear DNA content of 7 pg. Limitations on cell size resulting from a high metabolic rate may have constrained evolution of DNA content and could explain why the extensive heterochromatic additions that are common in some groups of mammals are absent in bats. Chromosomes of bats have been well studied; detailed chromosomal banding data are available for nearly all the species used in this investigation. However, no significant correlations were found between DNA content and karyotypic characteristics such as 2n, fundamental number, and rate or pattern of chromosomal evolution.     

VARIATION OF NUCLEAR DNA CONTENT IN HELIANTHUS ANNUUS (ASTERACEAE)

Nuclear 2C DNA content was determined by laser flow cytometry for 13 diploid (2n = 34) lines (cultivated varieties and inbred lines) of Helianthus annuus. Mean DNA amount of second leaf nuclei varied from 6.01 to 7.95 pg (32%) among lines. Mean DNA content varied up to 19% within lines. Variability in mean DNA content exceeding 27% and 48% was detected among leaves from different nodes of plants of the open-pollinated variety, Californicus, and the inbred line, RHA 299, respectively. The root tip and shoot tip nuclei of H. annuus have been reported to consist of a mixture of aneuploid (17 to 33 chromosomes) and diploid (34 chromosomes) cells, a condition called aneusomaty. Chromosome counts of root tips and an analysis of the distribution of DNA content of large numbers of nuclei from leaves indicate that aneusomaty either does not occur, or is not common, among the lines investigated. The intraspecific, intraline, and intraplant variation in DNA content in H. annuus support the concept that a sizable portion of a plant genome is unstable and subject to rapid changes in DNA amount.     

羟基喜树碱诱导肝癌细胞凋亡前后细胞核蛋白质组变化的定量分析

对羟基喜树碱诱导肝癌细胞凋亡前后的细胞核蛋白质组进行定量研究,获得凋亡前后细胞核蛋白质组中差异蛋白表达量相对变化的信息,为在亚细胞定量蛋白质组水平上深入探讨羟基喜树碱的作用机理提供实验依据。分离提取羟基喜树碱诱导肝癌细胞凋亡前后的细胞核并鉴定其纯度,用含稳定同位素的化学试剂c-ICAT标记细胞凋亡前后的细胞核蛋白,对细胞核标记蛋白进行消化和纯化,利用基于多维色谱-线性离子阱/静电场轨道阱质谱联用技术的鸟枪（Shotgun）法策略及c-ICAT定量策略分析鉴定蛋白质,获得同一种肝癌细胞核蛋白质在凋亡前后细胞中的表达量变化比值。分析鉴定了在细胞凋亡前后的表达量差异有显著统计学意义（P〈0.05）的肝癌细胞核蛋白42个,其中,12个蛋白的表达量在羟基喜树碱诱导细胞凋亡后下调,30个蛋白的表达量在凋亡细胞中上调。这些差异蛋白的分子功能主要与细胞增殖、凋亡和分化、能量代谢、核酸代谢以及细胞骨架相关。     

DROUGHT STRESS RESPONSES OF MICROSERIS SPECIES DIFFERING IN NUCLEAR DNA CONTENT

Anatomical and physiological responses to drought stress were compared in two Microseris species differing in DNA content and originating from contrasting habitats relative to water availability (M. bigelovii, DNA = 2.6 pg nucleus^–1, more xeric; M. laciniata, DNA = 6.8 pg nucleus^–1, mesic). Leaf mesophyll cell volume was positively correlated with DNA content and negatively correlated with tissue elasticity, i.e., low ϵ̄ and thin cell walls. Drought stress increased leaf tissue elasticity (lower ϵ̄, thinner cell walls). Cell volume, cell wall thickness, cell number, and leaf area were decreased most by drought stress in M. laciniata. Osmotic adjustment with a 20% increase in total solutes (mostly amino acids) after stress was observed in both species, but their estimated contribution to the change in osmotic potential was larger in M. bigelovii. These findings indicate that the Microseris species studied respond to low water availability by maintaining turgor with 1) small cell volumes, 2) elastic tissues (low ϵ̄, thin cell walls), and 3) osmotic adjustment. Both enhanced tissue elasticity and small cell volume appear to be inherent characteristics in M. bigelovii and drought-induced responses in M. laciniata. These data are compatible with the hypothesis that natural selection may influence DNA content through differential sensitivity of cell growth to environmental stress.     

染色体端粒DNA与核骨架的结合关系(简报)

端粒是真核生物染色体的一种特化结构,对于染色体的稳定以及染色体的完全复制有着十分重要的意义。许多种生物的端粒DNA序列已被发现:四膜虫,草履虫为(G_4T_2)_n;人、锥虫、短膜虫为(AG_3T_2)_n;尖毛虫、棘尾虫、游仆虫为(T_4G_4)_n;拟蓝芥菜为(AG_3T_3)_n。     

QUANTITATIVE MICROSPECTROPHOTOMETRY OF NUCLEAR DNA IN SELFING STRAINS OF THE MYXOMYCETE DIDYMIUM IRIDIS

Genetic and cytochemical investigations of the origin, development, nuclear activity, and ploidy level of Plasmodia obtained from selfed clones S-2 and B₁P-33 of the heterothallic myxomycete, Didymium iridis, are presented. To demonstrate that selfing did not result from contamination of the clones, or mutations at the mating-type locus, crosses were made between F₁ clones and clones of known mating types. The data were inconsistent with these two possibilities. DNA was quantified by Feulgen-DNA microspectrophotometry. All cellular phases studied (logarithmic amoebae, swarmers, and encysted amoebae) appear to be haploid, with the nuclear DNA being in the replicated (2C) state. The plasmodia are in all cases diploid; however, the data indicate that the selfed Plasmodia are in an extended G₁ condition. The nuclear DNA content of these is therefore 2C, whereas that of the cross Plasmodium is 4C. Sporangial nuclei exhibit DNA in diploid replicated (4C) category.