保存方法和保存时间对竹子核DNA含量（2C-值）检测的影响

竹子核DNA含量（2C-值）的检测对竹资源的科学研究具有重要意义,而大部分野外采集的样本,通过不同方法保存后,均使用流式细胞仪技术进行核DNA含量检测。本文选取麻竹（Dendrocalamuslati—florus）、筇竹（Chimonobambusatumidissinoda）和毛花酸竹（Acidosasapurpurea）三种竹子样本,使用硅胶保存法和Sampleprotector试剂保存法分别保存4d、8d、12d、16d后,采用流式细胞术检测样品2c．值。CV值可以用来反映数据检测结果质量,是对检测结果准确性以及精确性的评价标准,我们通过样品CV值的大小和2c-值的变异率来评价保存方法和保存时间对竹子2c-值检测的影响。方差分析显示,保存时间对CV值具有显著性影响（P〈0．001）,随着保存时间增大,CV值增大;保存方法对2c-值变异率有显著性影响（P〈0．001）。硅胶保存法保存后的样品,测量值比新鲜材料大;Sampleprotector试剂保存法保存后,测量值比新鲜材料小。因此,随着保存时间的增加,样品CV值增大,引起检测结果质量降低。研究发现,硅胶保存法和Sampleprotector试剂保存法会影响竹子样本2c．值大小,但2c-值大小的变化小于10％。     

尿样在SELDI技术中的优化研究

目的：建立表面增强激光解吸离子化飞行时间质谱（SELDI．TOF／MS）技术检测尿液样本的方法。方法：采用SELDI技术及弱阳离子交换表面蛋白芯片（CM10）对糖尿病病例组和正常对照组的尿液样本进行分析,从尿液标本的采集、样品保存、上样浓度的控制、实验仪器的内外校准、实验结果重复性验证与分析等方面进行实验条件的优化。结果：反复冻融3次以上的样品经SELDI检测的出峰数量和峰强度情况较差;以1：1或1：2的浓度作倍比稀释后的样本经芯片检测得到的蛋白峰强度和蛋白数量最优;对两组样本重复检测3次,蛋白丰度的平均变异系数（CV值）分别为0．121和0．095;两组样本共检测到202个蛋白峰,其中差异表达蛋白29个,在肝纤维化组中表达上调13个,表达下调16个。结论：初步建立了SELDI技术检测尿液样本的方法,提高了SELDI技术检测尿液样本的质量。     

毛竹基因组大小测定

毛竹（Phyllostachys edulis）属禾本科（Poaceae）竹亚科（Bambusoideae）刚竹属（Phyllostachys）,是我国分布和栽培面积最大的经济竹种,有着广泛的开发前景。本实验以水稻（Oryza sativa）为内标,用流式细胞仪对水稻和竹子样品的PI发射荧光强度进行测定,通过比较水稻与毛竹样品峰值的倍数关系,计算出毛竹的基因组大小。对24组样品进行重复测试,测得毛竹基因组大小为2075.025±13.08Mb,即2C DNA含量为4.24pg（以1pg DNA=0.978×10^9bp计算）。毛竹基因组大小测定为毛竹基因组文库的建立及其基因组学研究奠定了重要基础。     

两种粪便保存方法对肠道菌群结构研究的影响

目的比较2种粪便保存方法（室温法和Invitek公司的粪便稳定剂保存法）对菌群结构研究的影响。方法应用PCR-变性梯度凝胶电泳技术（PCR-DGGE）方法,对用2种方法保存的3位志愿者粪便样品进行菌群结构的分析。结果室温法保存粪便样品24h后,S1个体菌群结构与原始样品的菌群结构相似度为83％,S2和S3的菌群结构与其原始样品的相似度仅为77％。而使用粪便稳定剂保存1d,期间各时间点样品菌群结构与原始样品相比变化较小,相似度在80％-90％。结论粪便稳定剂具有一定的稳定样品菌群结构的作用,在新鲜粪佰样品不能寺刻讲行深冻的情况下,使用粪便稳定剂是一种较好的样品保存方法。     

川金丝猴尿液类固醇激素的保存时效性

尿液类固醇激素检测已经广泛运用于野生动物的生理机能、健康状况和繁殖状态的研究,由于分析条件以及样品采集时间限制,一般尿液样品需保存一段时间后才能在实验室分析,不同物种尿液类固醇在不同保存条件的保存时效有差异。本研究利用2只成年雄性和4只成年雌性的尿液样品共21份,确定川金丝猴尿液类固醇的保存时效和保存方法。结果表明:4℃时,雄性川金丝猴尿液睾酮、雌性尿液睾酮、孕酮的保存时效为7 d左右;雌性尿液雌二醇的保存时效在3 d以内。-20℃时,雄性川金丝猴尿液中睾酮的含量在60 d内保持稳定;雌性尿液中睾酮、孕酮和雌二醇的含量在60 d、45 d、60 d内保持稳定。-20℃保存川金丝猴尿液样品是一种有效、可靠的方法。     

不同温度及时间对保存血液有效期和质量的影响

目的 :研究不同温度对血液液状保存时保存损伤机制的影响 ,并探讨相应的防范措施。方法 :取 10名健康献血员静脉血 ,混合于CP2D A保存液中 ,均分为 2组 ,分别保存于 0℃和 4℃环境条件下 ,分别于设定的时间 (第2 1d和第 4 2d)以shafiq UR rehman法检测膜磷脂 ,同步法检测Na K ATP酶、纯化PDE法检测CaM、分光光度法检测LPO等指标。结果 :固定温度条件下随时间的延长血液过氧化反应增强 ,保存损伤作用增加 ;同一时期内保存损伤作用随温度的降低而减轻 ,以 4℃组血液老化明显。结论 :血液保存损伤作用随保存期的延长而增强 ,随保存温度的降低而改善 ,并指出血液液状保存所存在的问题与展望。     

11种灭活型样本保存液对病毒核酸保护效果的比较

收集11种不同厂家的灭活型样本保存液,将甲型流感病毒加入保存液和生理盐水中,在4℃、25℃和37℃条件下保存0 h、2 h、4 h、6 h和24 h后,分别提取各组的病毒核酸,并通过逆转录实时荧光PCR检测病毒载量变化,以探究不同样本保存液对病毒核酸保护效果是否存在差异。结果发现不同样本保存液中的病毒载量随保存时间和温度变化存在显著差异。据此可将11种灭活型样本保存液的保存效果分为四类：(1)优秀产品：在任一温度（4℃、25℃、37℃）条件下,即使保存24h时病毒核酸都未发生明显降解,占比27.2%(3/11);(2)良好产品：低温（4℃）和室温（25℃）情况下核酸未出现降解,但在高温（37℃）条件下6 h后保存效果明显下降,占比27.2%(3/11);(3)合格产品：低温（4℃）条件下对病毒核酸具有较好的保护效果,但在室温（25℃）和高温（37℃）情况下随保存时间延长其保护效果显著下降,占比18.1%(2/11);(4)不合格产品：任一保存条件下对病毒核酸的保护效果都较差,甚至加入病毒后立即导致病毒核酸发生快速降解,占比27.2%(3/11)。以上结果说明不同厂家样本保存液对病毒核酸...     

组织保护剂对病毒核酸与豚鼠皮肤组织样本RNA的保存效果探究

病毒核酸和生物组织样本RNA容易受到外部环境的影响,极易发生降解,造成实验结果产生严重偏差。以病毒核酸与豚鼠皮肤组织样本RNA为研究对象,探究组织保护剂保存它们在不同温度放置不同时间后,对病毒载量以及豚鼠皮肤组织样本中RNA的保护效果。结果发现,在4℃保存30 d,25℃保存7 d或37℃保存24 h后,与初始病毒核酸量相比较,组织保护剂中保存的病毒载量未发生明显变化（P>0.05）。在4℃保存30 d,25℃保存7 d或37℃保存24 h后,与液氮储存组相比较,组织保护剂组与市售RNA later组均可以保持豚鼠皮肤组织中样本RNA的提取量和纯度,差异无统计学意义（P>0.05）。结果表明,组织保护剂可作为科研或临床组织样本的储存保存液,在4℃、25℃以及37℃条件下放置一定时间,不影响病毒核酸的病毒载量以及豚鼠皮肤组织样本RNA的提取量和纯度,使样本保存更简便高效。     

江西铅山红芽芋胚性愈伤组织的包埋干燥法超低温保存

对江西铅山红芽芋（Colocasia esculenta var．cormosus cv．Hongyayu）胚性愈伤组织包埋干燥法超低温保存进行了初步的研究。结果表明：江西铅山红芽芋胚性愈伤组织包埋干燥法超低温保存较佳的条件为：0．75mol·L-1蔗糖预培养3d;脱水方式为空气干燥7h或硅胶干燥11h;化冻温度为37℃（2min）;冻后培养条件为暗培养7d再转到光周期中培养。此方法超低温保存后的平均成活率约为45％。超低温保存时间以及是否去除包裹的褐藻酸钙对其成活率无显著性影响。形态学和细胞学检测表明红芽芋胚性愈伤组织冻后再生苗与母本材料相比没有发生变异。     

深色果蔬维生素C检测方法的优化与比较

目的：优化2,6-二氯靛酚钠滴定法和高效液相色谱法检测维生素C含量操作规范性及适用性。方法：对检测条件的设置、试剂及样液的保存时间、提取剂及浓度的选择、提取过程、脱色剂用量及2种检测方法的精密度、重复性和加标回收率等关键影响因素进行比较。结果：高效液相色谱法检测设置C18（5μm,4.6×250mm）色谱柱,0.1%草酸为流动相,流速1mL/min,柱温30℃,检测波长254nm,所得图谱保留时间适宜,峰形良好,维生素C标准液浓度在0.025～0.3mg/mL范围内线性关系良好,回归方程为：y=46 116x+173.26,R2为0.999 2;维生素C标准液在4～6℃保存下48h内可用、2,6-二氯靛酚钠溶液在4～6℃保存下应在12d内使用,待测液制备完成后应立即测定,若无法立即测定,可于4～6℃冰箱中保存1.5h;2%草酸为提取剂效果最佳,样品加提取液匀浆后迅速定容、过滤和检测,不可久置;使用2,6-二氯靛酚钠滴定法时需添加0.4g/30mL的活性炭进行脱色;精密度、重复性及加标回收率均符合测定要求。结论：2种检测方法都适用于深色果蔬维生素C含量检测,各有特点,可根据测定要求及实际条件选择适宜的方法。     

The Determination of Nuclear DNA Content (2C value) on Some Representative Genus and Species of Magnoliaceae

The plant nuclear DNA content (2C value) is a principal characteristic parmeter to describe biodiversity of species,which has important significance on the study of plant resources. In this study, we choosed 23 species from 10 representative genera (Magnolia、Michelia、Manglietia、Liriodendron、Talauma、 Paramichelia、Tsoongiodendron、Manglietiastrum、Kmeria、Parakmeria) of Magnoliaceae in China. All samples were determined using a flow cytometry technique with a standard of Zea mays (545pg/2C). The amount of nuclear DNA among these species ranged from 325pg (317850Mbp) to 1361pg (1331058Mbp) for Pgrandiflora, Mofficinalis subsp. biloba respectively, and the coefficient of variation (CV) were less than 5%. The results of the study will not only provide references for determination of the nuclear DNA content of Magnoliaceae and other plants, but also lay the foundation for the utilization and conservation of Magnoliaceae plant resources.     

Determination of ploidy levels in Ipheion uniflorum (R. C. Graham) Rafin (Liliaceae)

In this study, chromosome number and ploidy levels of Ipheion uniflorum cv. "Wisley Blue" (spring starflower) were determined. In meristematic root tip cells, chromosome number was found as 2n = 12 and 4n = 24. The ratios of diploid and tetraploid cells were found as 80.74% and 19.26%, respectively. In differentiated root tissues and mature leaf tissues ploidy levels were analysed by flow cytometry and polysomaty were found in both organs. In differentiated root tissues, ploidy levels were found as 2C, 4C, 8C and 16C DNA. In root tissues percentages of 2C, 4C, 8C and 16C nuclear DNA content were observed as 57.2%, 33.1%, 2.47% and 7.23%, respectively. In mature leaf tissues, ploidy levels were determined 2C, 4C, 8C and 16C DNA. In this tissue the frequency of 4C DNA was found very higher (74.3%) and 2C DNA content was determined as 19.2%. In mature leaf tissue, 8C and 16C nuclear DNA contents were observed as 2.72% and 3.78%, respectively. When nuclear DNA contents in leaves and roots were compared, an apparent difference in 2C and 4C DNA contents was found.     

Comparison of fresh, ethanol-preserved, and paraffin-embedded samples in DNA flow cytometry

Fresh, ethanol-preserved, and formalin-fixed and paraffin-embedded samples taken from the same part of 15 human tumors, and from one normal spleen and one pancreas were analyzed for nuclear DNA content by flow cytometry. The coefficient of variation (CV) values of the G1 peaks were smaller in the fresh than in the other samples (P less than 0.001). The DNA ploidy of the tumors was the same in all types of samples. The DNA indices (DIs) measured from either ethanol-preserved or formalin-fixed tissue correlated strongly with those obtained from fresh tissue (P less than 0.001), although they tended to be somewhat smaller in the fresh samples. The S-phase fractions measured from all types of samples were of the same order of magnitude in most cases (P less than 0.001). Uninterpretable histograms were most often obtained from fresh samples. Identical DI values and rather constant S-phase fractions were obtained from ethanol-preserved samples stored at 4 degrees C for up to 5 months. It is concluded that all three types of samples are suitable for the determination of DNA ploidy, DI, and S-phase fraction and that 50% ethanol is suitable for long-term preservation of flow cytometric samples.     

Plant Genome Size Measurement with DNA Image Cytometry

To test the reliability of DNA image cytometry for the measurement of nuclear DNA content in plant material, we conducted independent experiments in two laboratories using different image analysis instruments for densitometric measurement of nuclear DNA amount in Feulgen-stained squash preparations of root tips. The 2C nuclear DNA content of the nine species studied spanned a 100-fold range (approx. 0.3–33 pg). The estimates of nuclear DNA content measured with image cytometry methods were comparable to values obtained previously using both photometric cytometry and flow cytometry. Image cytometry methods showed little variation among repeated experiments within each laboratory or among different operators using the same instrument. Furthermore, the interphase-peak method (measurement of several hundred interphase nuclei per slide) was comparable to the classical prophase/telophase approach (measurement of ten early prophase and ten late telophase nuclei per slide). Hence, DNA image cytometry gives accurate and reproducible results and may be used as an alternative to photometric cytometry in plant nuclear DNA content measurements. In the present study, we propose that two standards for quality control of nuclear DNA content measurement are used in plant DNA image cytometry: (1) the coefficient of variation of the peak should be lower than 6%, and (2) the 4C/2C ratio should be between 1.9 and 2.1.     

Chromosomal DNA content of sweet pepper determined by association of cytogenetic and cytometric tools

The nuclear DNA content of sweet pepper (Capsicum annuum L. var. annuum, 2n = 24) has been measured by flow and image cytometries but the DNA content of each chromosome of this species has not yet been regarded. DNA content of individual chromosomes has been quantified by the flow karyotyping technique, which requires a great quantity of intact metaphasic chromosomes and methods that allow the characterization of individual chromosomes; however, the obtainment of adequate number of metaphases can be difficult in some species like C. annuum. In order to estimate the DNA content of each C. annuum var. annuum cv. "New Mexican" chromosome, flow and image cytometries were associated with the cytogenetic methodology. First, the DNA amount (2C = 6.90 pg) was established by flow cytometry. Integrated optical density (IOD) values were calculated by image cytometry for each Feulgen stained metaphasic chromosome. Then, by distributing the correspondent metaphasic value (4C = 13.80 pg) proportionally to average IOD values, the following chromosomal DNA contents were obtained in pg: 0.74 (chromosome 1), 0.67 (2), 0.61 (3, 4), 0.60 (5), 0.59 (6, 7), 0.58 (8), 0.57 (9), 0.56 (10) and 0.39 (11, 12). This study reports an alternative and reproducible technique that makes quantifying the chromosomal DNA content possible.     

Heat pretreatment increases resolution in DNA flow cytometry of paraffin-embedded tumor tissue

BACKGROUND: Flow cytometry of single-cell suspensions prepared by enzymatic digestion from formalin-fixed, paraffin-embedded tissue suffers from several major drawbacks. The most important factors that influence the results are the high and unpredictable coefficients of variation (CVs) of the G0/G1 peak in the DNA histogram and reduction of propidium iodide (PI) intercalation with DNA, resulting from protein cross-linking by formalin. METHODS: In this study we introduce a heating step (2 h incubation in citrate solution at 80 degrees C) prior to a brief pepsin digestion of tissue sections in the protocol for DNA content analysis of formalin-fixed and paraffin-embedded tissue. This new method is compared with established methods for the preparation of cell suspensions from frozen and paraffin-embedded tissues with respect to cell yield, DNA histogram resolution, DNA dye saturation kinetics, cell cycle parameters, and antigen retrieval in various epithelial and nonepithelial tissues. RESULTS: The recovery of single cells from the paraffin sections was doubled by the heat treatment step, while the limited time of proteolysis resulted in decreased cell debris. Furthermore, an increased fraction of cells became cytokeratin-positive, while these immunocytochemically stained cells also exhibited a higher mean fluorescence intensity. The DNA histograms prepared from cell suspensions obtained according to this new protocol showed a significantly improved resolution, leading to a better identification of peridiploid cell populations. Heat pretreatment of paraffin-embedded archival tissue sections showed PI saturation kinetics similar to, or even better than, those of fresh unfixed tissues, independent of duration of fixation. CONCLUSIONS: This new method, making use of routinely available antigen retrieval principles, thus allows high-resolution DNA analysis of routinely fixed and paraffin-embedded tissue samples. Using external reference cells, inter- and intralaboratory standardization of DNA histograms can be achieved.     

Flow cytometric measurement of nuclear DNA content inCapsicum (Solanaceae)

Nuclei were isolated from leaf tissue of differentCapsicum species and the relative fluorescence intensity was measured by flow cytometry after propidium iodide staining.Pisum sativum nuclei with known nuclear genome size (9.07 pg) were used as internal standard to determine nuclear DNA content of the samples in absolute units. The 2C DNA contents ranged between 7.65 pg inC. annuum and 9.72 pg inC. pubescens, and the general mean of the genus was 8.42 pg. These values correspond, respectively, to 1C genome size of 3.691 (C. annuum), 4.690 (C. pubescens) and 4.063 (general mean) Mbp. In general, white-flowered species proved to have less DNA, with the exception ofC. praetermissum, which displayed a 2C DNA content of 9.23 pg. It was possible to divide the studied species into three main groups according to their DNA content, and demonstrate differences in DNA content within two of the three species complexes established on the basis of morphological traits.     

Flow cytometric analysis from fish samples stored at low,ultra-low and cryogenic temperatures

Flow cytometry is a valuable tool in biomedical and animal sciences. However, equipment used for such analysis presents limitations at field conditions, suggesting then preservation procedures for future analysis at laboratory conditions. In this study, freezing at low (−20 °C), ultra-low (−80 °C) and cryogenic temperatures (−196 °C, i.e. liquid nitrogen) were used as preservation procedures of fish tissue. Samples were maintained in 0.9% NaCl or lysing solution, and stored at the temperatures above for 0 (fresh control), 60, 120 and 180 days of storage. After storage, the samples were thawed and proceeded to flow cytometric analysis. Storage at low temperatures (−20 °C), both in lysing and 0.9% NaCl, exhibited poor results when analyzed after 60, 120 and 180 days, showing noisy peaks, deviation in the DNA content and absence of peaks. Ultralow (−80 °C) and cryogenic (−196 °C) temperatures, both in lysing solution and 0.9% NaCl, showed good results and high quality of histograms. Both storage procedures gave similar histograms and DNA content in comparison with control group (fresh) even after 60, 120 and 180 days of storage, exhibiting the main peak at 2C content from diploid cells and a secondary peak at 4C derived from dividing cells. In conclusion, samples may be stored for 180 days at −80 °C and −196 °C in both, 0.9% NaCl or lysing solution. As cryogenic temperatures in liquid nitrogen permits indefinite storage, this procedure should be used for long-term preservation.     

Assessment of genetic stability of the germplasm lines of medicinal plant <Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi (Huang-qin) in long-term,in vitro maintained cultures

An approach of combining flow cytometry (FCM) analysis with morphological and chemical profiling was used to assess the genetic stability and bioactive compound diversity in a Scutellaria baicalensis Georgi (Huang-qin) germplasm collection that was clonally maintained in in vitro for a period of over 6 years. Based on the FCM analysis of nuclei samples from young shoots, the nuclear DNA content of S. baicalensis was calculated as 0.84 pg/2C. FCM analysis showed no significant variation in the nuclear DNA contents and ploidy levels in the long-term in vitro maintained germplasm lines. Germplasm lines, acclimatized to ex vitro conditions, exhibited distinctive plant growth and bioactive compound production capacities. The high level of genetic stability observed in in vitro maintained S. baicalensis lines opens up a variety of opportunities such as allowing long-term aseptic preservation and easy distribution of well-characterized germplasm lines of this medicinal plant species. This study represents a novel approach for continuous maintenance, monitoring, and production of medicinal plant tissues with specific chemistry.