我们感谢乔治·贾维斯，玛莎博克和贝特Hecox - 李，海洋生物实验室，他们在拍戏的帮助。

1.媒体的制备注意:使用盐度16.5个百分点（PSU）的一半稀释Brujewicz人造海水。其他人工海水也经常用于培养轮虫臂 25,26。 <ol><li>加454毫摩尔NaCl，26毫的MgCl 2，27毫硫酸镁 ，10毫米氯化钾和10mM的CaCl 2到4.5升蒸馏水（最终体积为5升）。另外，使用去离子水稀释代替蒸馏水。溶解所有其他盐后添加氯化钙 。 </li><li>准备0.48中号碳酸氢钠原液（200倍浓度）。将25ml添加到上述溶液中。的NaHCO 3的最终浓度为2.4毫摩尔。 </li><li>制备0.4M的溴化钠储备液（500X浓度）。加入10ml其添加到上述溶液中。溴化钠的最终浓度为0.8毫摩尔。补至5升蒸馏水。 </li><li>过滤用0.45μm的膜过滤器的溶液。在使用前用无菌水两次稀释（V / V）。 注意:可以使Brujewicz人工海水的2倍浓度作为原液。 </li></ol> 2.一般培养条件<ol><li>培养实验室饲养或在20和30℃之间的无菌100毫升烧杯野生捕获轮虫。较高的温度导致寿命较短，加速繁殖。使用25℃下的实验的方便性。轮虫密度或人工海水量是不是在这里一个大问题。 </li><li>文化饮食微藻在人工海水中11。见斯内尔等人 （2014年）的详细信息11。通常情况下，使用四爿tetrathele（〜2×10 5个细胞/ ml 27,28），T。 suecica（〜6×10 5个细胞/ ml 25,29），和微绿球藻 （〜7×10 6个细胞/ ml 30,31），由于饮食藻（种类，培养康迪特离子，生化成分）显著影响轮虫臂尾轮虫的存活时间，用同一地段微藻各实验组。 </li><li>喂养偶尔改变介质（ 如 ，喂，每2天，每周接种）保持在分批培养轮虫的股票群体。许多新生儿和成人轴承鸡蛋2-3个可以在轮虫是在最佳条件下进行观察。 注:另一种方式来获得实验轮虫是孵化休眠卵。从休眠卵孵出轮虫被认为是很好地同步，并且他们的寿命是不从来自amictic鸡蛋11孵出轮虫显著不同。然而，从休眠卵轮虫早于从amictic鸡蛋开始再现。因此，需要对它们的繁殖性状测量慎用。 </li></ol> 3.同步轮虫通过预培养<ol><li>选择从ST单轮虫玉珠人口和培养在2.1-2.3如上所述建立一个亚群将被用于实验。通常培养两周。 </li><li>收集来自亚群蛋承载轮虫（收集将用于实验的个体的双号）。培养它们作为一个单一的队列（密度:〜50个/毫升），在新鲜的介质下自由采食在2.1-2.3中描述的6孔培养板中。控制人口密度是重要的，因为条件培养基影响轮虫臂 32,33的生殖生理。 </li><li>转移从成人的第一个卵孵化到新制备培养基新生儿。重复此过程在2-3代。 </li><li>使用用于测量生存时间的特定时间段（ 例如 ，&lt;3小时）内画影线的新生儿。为了避免可能偏向于选择单一的个体，虽然很不可能的，用几个不知疲倦重复性检查侧亚群。 注:由于轮虫繁殖通常只无性这种情况下，确保无男性是整个实验过程中存在。男性比新生儿小，典型的移动比女性更快。混交雌体具有amictic女性在一定条件下29种不同的寿命。 </li></ol> 4.生存时间的测量<ol><li>在塑料板代替新生儿（通常24或48孔板，每孔含有1ml人工海水）。 </li><li>在24小时的时间间隔，如果在较高的温度（30℃以上）传送轮虫到新制备的培养基，或在12小时的时间间隔。记录的后代的数量和每一个人无论是死是活。记录轮虫死时电晕的纤毛运动完全停止。 注意:轮虫经常附着到孔的侧壁。水的轻柔吹打有助于找到他们。如果轮虫找不到或ArË小心被移液破坏，记录他们为"封杀"，而不是"死"。 </li><li>新生儿取出实验时，轮虫正在积极重现。新生儿快速增长，这是有时很难从实验轮虫区分。 </li></ol> 5.数据分析<ol><li>创建Kaplan-Meier生存曲线（ 图1和2）通过在Y轴和时间在X轴上标绘的累积存活率。这是存活数据的最常见的代表。使用的存活时间34统计比较的非参数数秩检验（也称为曼特尔-考克斯测试）。对数秩检验也被包括在其他标准统计软件包如JMP和R. 注:请不要使用学生t检验或后面的参数多重比较方差分析的分析，因为正态分布通常不是由生存数据35满足。此外，这些方法具DS不采取截尾的个人考虑。如果没有删数据曼 - 惠特尼U检验都可以使用。 </li></ol>

<ol>
	<li>Wallace, R. L., Snell, T. W., Ricci, C., Nogrady, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Rotifera Vol.1: Biology, ecology and systematics. , (2006).</li><li>Segers, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Annotated checklist of the rotifers (Phylum Rotifera), with notes on nomenclature, taxonomy and distribution. , (2007).</li><li>Mark Welch, D. B., Meselson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+the+evolution+of+bdelloid+rotifers+without+sexual+reproduction+or+genetic+exchange.">Evidence for the evolution of bdelloid rotifers without sexual reproduction or genetic exchange.</a> Science. 288 (5469), 1211-1215 (2000).</li><li>Suga, K., Mark Welch, D., Tanaka, Y., Sakakura, Y., Hagiwara, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+expressed+sequence+tags+of+the+cyclically+parthenogenetic+rotifer+Brachionus+plicatilis.">Analysis of expressed sequence tags of the cyclically parthenogenetic rotifer Brachionus plicatilis.</a> PLoS ONE. 2, e671 (2007).</li><li>Denekamp, N. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discovering+genes+associated+with+dormancy+in+the+monogonont+rotifer+Brachionus+plicatilis.">Discovering genes associated with dormancy in the monogonont rotifer Brachionus plicatilis.</a> BMC Genomics. 10, 108 (2009).</li><li>Lee, J. -. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sequence+analysis+of+genomic+DNA+(680+Mb)+by+GS-FLX-Titanium+sequencer+in+the+monogonont+rotifer,+Brachionus+ibericus.">Sequence analysis of genomic DNA (680 Mb) by GS-FLX-Titanium sequencer in the monogonont rotifer, Brachionus ibericus.</a> Hydrobiologia. 662 (1), 65-75 (2010).</li><li>Flot, J. -. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+evidence+for+ameiotic+evolution+in+the+bdelloid+rotifer+Adineta+vaga.">Genomic evidence for ameiotic evolution in the bdelloid rotifer Adineta vaga.</a> Nature. 500 (7463), 453-457 (2013).</li><li>Dunn, C. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Broad+phylogenomic+sampling+improves+resolution+of+the+animal+tree+of+life.">Broad phylogenomic sampling improves resolution of the animal tree of life.</a> Nature. 452 (7188), 745-749 (2008).</li><li>Yoshinaga, T., Kaneko, G., Kinoshita, S., Tsukamoto, K., Watabe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+mechanisms+of+life+history+alterations+in+a+rotifer:+a+novel+approach+in+population+dynamics.">The molecular mechanisms of life history alterations in a rotifer: a novel approach in population dynamics.</a> Comp. Biochem. Physiol. B Biochem. Mol. Biol. 136 (4), 715-722 (2003).</li><li>Dahms, H. -. U., Hagiwara, A., Lee, J. -. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ecotoxicology,+ecophysiology,+and+mechanistic+studies+with+rotifers.">Ecotoxicology, ecophysiology, and mechanistic studies with rotifers.</a> Aquat. Toxicol. 101 (1), 1-12 (2011).</li><li>Snell, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rotifers+as+models+for+the+biology+of+aging.">Rotifers as models for the biology of aging.</a> Int. Rev. Hydrobiol. 99 (1-2), 84-95 (2014).</li><li>Snell, T. W., Johnston, R. K., Gribble, K. E., Mark Welch, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rotifers+as+experimental+tools+for+investigating+aging.">Rotifers as experimental tools for investigating aging.</a> Invertebr. Reprod. Dev. 59, 5-10 (2015).</li><li>Kaneko, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+characterization+of+Mn-superoxide+dismutase+and+gene+expression+studies+in+dietary+restricted+Brachionus+plicatilis+rotifers.">Molecular characterization of Mn-superoxide dismutase and gene expression studies in dietary restricted Brachionus plicatilis rotifers.</a> Hydrobiologia. 546, 117-123 (2005).</li><li>Yoshinaga, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin-like+growth+factor+signaling+pathway+involved+in+regulating+longevity+of+rotifers.">Insulin-like growth factor signaling pathway involved in regulating longevity of rotifers.</a> Hydrobiologia. 546, 347-352 (2005).</li><li>Ozaki, Y., Kaneko, G., Yanagawa, Y., Watabe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calorie+restriction+in+the+rotifer+Brachionus+plicatilis+enhances+hypoxia+tolerance+in+association+with+the+increased+mRNA+levels+of+glycolytic+enzymes.">Calorie restriction in the rotifer Brachionus plicatilis enhances hypoxia tolerance in association with the increased mRNA levels of glycolytic enzymes.</a> Hydrobiologia. 649 (1), 267-277 (2010).</li><li>Kailasam, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+calorie+restriction+on+the+expression+of+manganese+superoxide+dismutase+and+catalase+under+oxidative+stress+conditions+in+the+rotifer+Brachionus+plicatilis.">Effects of calorie restriction on the expression of manganese superoxide dismutase and catalase under oxidative stress conditions in the rotifer Brachionus plicatilis.</a> Fish. Sci. 77 (3), 403-409 (2011).</li><li>Garc&#236;a-Garc&#236;a, G., Sarma, S., N&#250;&#241;ez-Orti, A. R., Nandini, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+the+mixture+of+two+endocrine+disruptors+(ethinylestradiol+and+levonorgestrel)+on+selected+ecological+endpoints+of+Anuraeopsis+fissa+and+Brachionus+calyciflorus+(Rotifera).">Effects of the mixture of two endocrine disruptors (ethinylestradiol and levonorgestrel) on selected ecological endpoints of Anuraeopsis fissa and Brachionus calyciflorus (Rotifera).</a> Int. Rev. Hydrobiol. 99 (1-2), 166-172 (2014).</li><li>Yang, J., Mu, Y., Dong, S., Jiang, Q., Yang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+the+expression+of+four+heat+shock+proteins+during+the+aging+process+in+Brachionus+calyciflorus+(rotifera).">Changes in the expression of four heat shock proteins during the aging process in Brachionus calyciflorus (rotifera).</a> Cell Stress Chaperones. 19 (1), 33-52 (2014).</li><li>Han, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sublethal+gamma+irradiation+affects+reproductive+impairment+and+elevates+antioxidant+enzyme+and+DNA+repair+activities+in+the+monogonont+rotifer+Brachionus+koreanus.">Sublethal gamma irradiation affects reproductive impairment and elevates antioxidant enzyme and DNA repair activities in the monogonont rotifer Brachionus koreanus.</a> Aquat. Toxicol. 155, 101-109 (2014).</li><li>Gribble, K. E., Jarvis, G., Bock, M., Mark Welch, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maternal+caloric+restriction+partially+rescues+the+deleterious+effects+of+advanced+maternal+age+on+offspring.">Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring.</a> Aging Cell. 13 (4), 623-630 (2014).</li><li>Yoshinaga, T., Hagiwara, A., Tsukamoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+periodical+starvation+on+the+survival+of+offspring+in+the+rotifer+Brachionus+plicatilis.">Effect of periodical starvation on the survival of offspring in the rotifer Brachionus plicatilis.</a> Fish. Sci. 67 (2), 373-374 (2001).</li><li>Kaneko, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calorie+restriction-induced+maternal+longevity+is+transmitted+to+their+daughters+in+a+rotifer.">Calorie restriction-induced maternal longevity is transmitted to their daughters in a rotifer.</a> Funct. Ecol. 25 (1), 209-216 (2011).</li><li>Lansing, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+transmissible,+cumulative,+and+reversible+factor+in+aging.">A transmissible, cumulative, and reversible factor in aging.</a> J. Gerontol. 2 (3), 228-239 (1947).</li><li>Yoshinaga, T., Hagiwara, A., Tsukamoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+periodical+starvation+on+the+life+history+of+Brachionus+plicatilis+O.+F.+M&#252;ller+(Rotifera):+a+possible+strategy+for+population+stability.">Effect of periodical starvation on the life history of Brachionus plicatilis O. F. M&#252;ller (Rotifera): a possible strategy for population stability.</a> J. Exp. Mar. Biol. Ecol. 253 (2), 253-260 (2000).</li><li>Gribble, K. E., Kaido, O., Jarvis, G., Mark Welch, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterns+of+intraspecific+variability+in+the+response+to+caloric+restriction.">Patterns of intraspecific variability in the response to caloric restriction.</a> Exp. Gerontol. 51, 28-37 (2014).</li><li>Snell, T. W., Johnston, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycerol+extends+lifespan+of+Brachionus+manjavacas+(Rotifera)+and+protects+against+stressors.">Glycerol extends lifespan of Brachionus manjavacas (Rotifera) and protects against stressors.</a> Exp. Gerontol. 57, 47-56 (2014).</li><li>Kim, H. -. J., Hagiwara, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+female+aging+on+the+morphology+and+hatchability+of+resting+eggs+in+the+rotifer+Brachionus+plicatilis+M&#252;ller.">Effect of female aging on the morphology and hatchability of resting eggs in the rotifer Brachionus plicatilis M&#252;ller.</a> Hydrobiologia. 662 (1), 107-111 (2011).</li><li>Kim, H. -. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-dependent+transcriptional+events+during+resting+egg+hatching+of+the+rotifer+Brachionus+manjavacas.">Light-dependent transcriptional events during resting egg hatching of the rotifer Brachionus manjavacas.</a> Mar. Genomics. 20, 25-31 (2015).</li><li>Gribble, K. E., Welch, D. B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Life-span+extension+by+caloric+restriction+is+determined+by+type+and+level+of+food+reduction+and+by+reproductive+mode+in+Brachionus+manjavacas+(Rotifera).">Life-span extension by caloric restriction is determined by type and level of food reduction and by reproductive mode in Brachionus manjavacas (Rotifera).</a> J. Gerontol. A Biol. Sci. Med. Sci. 68 (4), 349-358 (2013).</li><li>Kaneko, G., Kinoshita, S., Yoshinaga, T., Tsukamoto, K., Watabe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+expression+patterns+of+stress+protein+genes+during+population+growth+of+the+rotifer+Brachionus+plicatilis.">Changes in expression patterns of stress protein genes during population growth of the rotifer Brachionus plicatilis.</a> Fish. Sci. 68 (6), 1317-1323 (2002).</li><li>Kim, H. J., Sawada, C., Hagiwara, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavior+and+reproduction+of+the+rotifer+Brachionus+plicatilis+species+complex+under+different+light+wavelengths+and+intensities.">Behavior and reproduction of the rotifer Brachionus plicatilis species complex under different light wavelengths and intensities.</a> Int. Rev. Hydrobiol. 99 (1-2), 151-156 (2014).</li><li>Yoshinaga, T., Hagiwara, A., Tsukamoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+conditioned+media+on+the+asexual+reproduction+of+the+monogonont+rotifer+Brachionus+plicatilis+O.+F.+Müller.">Effect of conditioned media on the asexual reproduction of the monogonont rotifer Brachionus plicatilis O. F. Müller.</a> Hydrobiologia. 412, 103-110 (1999).</li><li>Ohmori, F., Kaneko, G., Saito, T., Watabe, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+growth-promoting+protein+in+the+conditioned+media+from+the+rotifer+Brachionus+plicatilis+at+an+early+exponential+growth+phase.">A novel growth-promoting protein in the conditioned media from the rotifer Brachionus plicatilis at an early exponential growth phase.</a> Hydrobiologia. 667 (1), 101-117 (2011).</li><li>Collet, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Modelling Survival Data in Medical Research. , 151-193 (1993).</li><li>Bouliotis, G., Billingham, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crossing+survival+curves:+alternatives+to+the+log-rank+test.">Crossing survival curves: alternatives to the log-rank test.</a> Trials. 12, A137 (2011).</li><li>Yang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+expression+of+manganese+superoxide+dismutase,+copper+and+zinc+superoxide+dismutase+and+catalase+in+Brachionus+calyciflorus+during+the+aging+process.">Changes in expression of manganese superoxide dismutase, copper and zinc superoxide dismutase and catalase in Brachionus calyciflorus during the aging process.</a> PloS ONE. 8 (2), e57186 (2013).</li><li>Snell, T. W., Johnston, R. K., Rabeneck, B., Zipperer, C., Teat, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+inhibition+of+TOR+and+JNK+pathways+interacts+to+extend+the+lifespan+of+Brachionus+manjavacas+(Rotifera).">Joint inhibition of TOR and JNK pathways interacts to extend the lifespan of Brachionus manjavacas (Rotifera).</a> Exp. Gerontol. 52, 55-69 (2014).</li><li>Klass, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aging+in+nematode+Caenorhabditis-elegans+-+major+biological+and+environmental-factors+influencing+life-span.">Aging in nematode Caenorhabditis-elegans - major biological and environmental-factors influencing life-span.</a> Mech. Ageing Dev. 6 (6), 413-429 (1977).</li><li>Priest, N. K., Mackowiak, B., Promislow, D. E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+parental+age+effects+on+the+evolution+of+aging.">The role of parental age effects on the evolution of aging.</a> Evolution. 56 (5), 927-935 (2002).</li></ol>

The authors have nothing to disclose.

目前的协议描述了测量在臂轮虫的存活时间的方法。关键的步骤是轮虫条件几代同步。当实验轮虫以及同步的，一个典型的I型的生存曲线是用很少的早期死亡率观察到几个以前的研究报告18,24,37,38。相比较差同步轮虫的存活时间的标准偏差因此变得更小，从而导致高的统计力量。同步也有望增加存活时间测量的再现 - 因为母亲在最佳条件下培养时，当前协议抵消母体世代的可能的有害作用。如果早期死亡率经过仔细同步仍在观察，考虑用新制备培养基，另外很多喂养藻类，或新成立的实验人群（ 即从协议3.1开始）。 此协议的一个限制是该井同步轮虫是潜在过分敏感。例如，在该延长寿命的化学品的筛选，通过该协议筛选一些化学物质可能无法检测到不良同步轮虫寿命显著影响（ 例如 ，从野生和批量养殖群体的个人）。因此，这样的实验的结果，应谨慎解释。 孕妇年龄对后代存活时间的影响也有报道在其他无脊椎动物模型，包括果蝇果蝇和线虫 39,40。虽然它是比较费时，这些长寿命模式，对于这些动物中的存活时间测量减少实验的变化超过几代同步过程将是有益的。

轮虫是微观世界性浮游动物（&lt;1毫米）构成门轮虫1。它们具有约1,000的体细胞，以及一个特性轮状睫状装置构成的简单的身体计划称为电晕，其用于运动和进纸。大多数轮虫属于类Monogononta或玄武湖的轮虫，其中包含约1600和500种，分别为2。 Monogonont轮虫一般同时具有有性和无性繁殖阶段（周期性孤雌生殖），而蛭形轮虫繁殖通过强制性孤雌生殖3。因此，有可能获得基因完全相同轮虫个人，从而确保在实验高再现性。此外，它们具有其它几个优点模式生物，如短寿命，易于培养，基因组和转录组序列数据4-7的可用性，以及独特的系统位置远离一rthropods和线虫8。因此轮虫是有希望在生态毒理学无脊椎动物模型和老化研究9-12。 下暴露于环境压力或化学品的生存时间是在这些研究领域一个13-19经常测量参数。但是，衡量轮虫的存活时间的时候，因为很容易受到他们的母亲的环境条件是需要谨慎。也就是说，在monogonont 臂尾轮虫manjavacas，雌性后代从母亲年龄比那些年轻的妈妈寿命较短;然而，产妇热量限制（CR），部分抵消了先进的孕产妇20岁的有害影响。在B.轮虫 ，母亲CR提供后代长寿，饥饿状态下存活时间长，并与抗氧化酶21,22表达增强相关的高氧化应激性。产妇年龄效应也已在蛭形轮虫23观察到。因此，实验轮虫的条件应仔细的存活时间测量同步前几代。 在这里，我们提供了以下几代的培养条件同步的轮虫臂存活时间测量的协议。间歇禁食（IF），其中轮虫周期性馈送CR的变化，施加于揭示的同步的效果由于中频对长寿22,24众所周知的效果。

<table border="0" cellpadding="0" cellspacing="0" width="688">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Sodium chloride</td>
			<td style="width:135px;">Wako</td>
			<td style="width:119px;">190-13921</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Magnesium chloride</td>
			<td style="width:135px;">Wako</td>
			<td style="width:119px;">136-03995</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Magnesium sulfate</td>
			<td style="width:135px;">Wako</td>
			<td>131-00427</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Potassium chloride</td>
			<td style="width:135px;">Wako</td>
			<td style="width:119px;">168-22111</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Calcium chloride</td>
			<td style="width:135px;">Wako</td>
			<td style="width:119px;">035-00455</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Sodium bicarbonate</td>
			<td style="width:135px;">Wako</td>
			<td style="width:119px;">199-05985</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Sodium bromide</td>
			<td style="width:135px;">Wako</td>
			<td style="width:119px;">190-01515</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Membrane filter (0.45 &#181;m pore size)</td>
			<td style="width:135px;">Millipore</td>
			<td style="width:119px;">HAWP04700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Culture plate, 6-well, non-treated</td>
			<td style="width:135px;">Thomas Scientific</td>
			<td style="width:119px;">6902D01</td>
			<td>Flat bottom</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Culture plate, 48-well, non-treated</td>
			<td style="width:135px;">Thomas Scientific</td>
			<td style="width:119px;">6902D07</td>
			<td>Flat bottom</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:268px;">Tetraselmis, Living</td>
			<td style="width:135px;">Carolina Biological Supply Company</td>
			<td style="width:119px;">152610</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">PRISM 6</td>
			<td style="width:135px;">GraphPad Software</td>
			<td style="width:119px;">Version 6.0d</td>
			<td></td>
		</tr>
	</tbody>
</table>

measurement of survival time in brachionus rotifers: synchronization of maternal conditions

Rotifers are microscopic cosmopolitan zooplankton used as models in ecotoxicological and aging studies due to their several advantages such as short lifespan, ease of culture, and parthenogenesis that enables clonal culture. However, caution is required when measuring their survival time as it is affected by maternal age and maternal feeding conditions. Here we provide a protocol for powerful and reproducible measurement of the survival time in Brachionus rotifers following a careful synchronization of culture conditions over several generations. Empirically, poor synchronization results in early mortality and a gradual decrease in survival rate, thus resulting in weak statistical power. Indeed, under such conditions, calorie restriction (CR) failed to significantly extend the lifespan of B. plicatilis although CR-induced longevity has been demonstrated with well-synchronized rotifer samples in past and present studies. This protocol is probably useful for other invertebrate models, including the fruitfly Drosophila melanogaster and the nematode Caenorhabditis elegans, because maternal age effects have also been reported in these species.

图1显示了同步较差人群（出两个重复的）的代表生存曲线。在这个实验中，轮虫要么美联储日常[ 自由采食 （AL）组]或隔日（IF组）。中位生存期在美联和IF组13和18日，分别。虽然这是众所周知的，如果延伸轮虫的寿命，本实验未能检测到的AL和IF组的寿命之间存在统计学显著差异。根据经验，在早期死亡率和生存率下降逐渐同步不足的结果在这个实验中观察到。损害所引起的不恰当的治疗或低水质为亚群轮虫趋于产生类似的结果。 当轮虫条件是最优的，以及同步的，早期死亡率几乎观察accordin甘氨酸轮虫往往在实验（ 图2）的后期阶段以同步的方式死去。中位生存期在美联和IF组13和20天，分别。虽然较少动物比图1中的实验中所用，在这些组之间寿命的差异有统计学显著。这是从先前已22发表超过五个实验的代表性结果。 <img alt="图1" src="/files/ftp_upload/54126/54126fig1.jpg" /> 图 1: 为进行间歇禁食（IF）不佳同步个人Kaplan-Meier曲线的AL组随意喂食整个实验，而中频组每隔一天喂食。 N = 11和N = 12为AL和IF组，分别为（N​​为在实验中使用的个人号码）。该实验perforMED在25℃。当数秩检验用于（P = 0.1207）检测人的寿命没有显著差异。然而，该数据难以解释，因为数秩检验，不应用来比较两个交叉存活曲线虽然测试已知是健壮36。没有建立的方法目前可用于穿越生存曲线截尾数据， <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54126/54126fig1large.jpg" target="_blank">请点击这里查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/54126/54126fig2.jpg" /> 图 2: 对经受中频同步个人Kaplan-Meier曲线的轮虫队列，通过预先培养获得的，进行相同的中频时间表（馈送隔日）。 N = 6和N = 8为AL和中频组，分别。该实验在25℃下进行。对数秩和检验，P = 0.0057。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54126/54126fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions at JoVE.com

Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions

Rotifers are microscopic zooplankton used as models in ecotoxicological and aging studies. Here we provide a protocol for powerful and reproducible measurement of survival time in Brachionus rotifers. Synchronization of culture conditions over several generations is of particular importance because maternal condition affects life history of offspring.

生存时间的测量<em&gt;臂</em&gt;轮虫:产妇条件同步

Rotifers are microscopic cosmopolitan zooplankton used as models in ecotoxicological and aging studies due to their several advantages such as short ...

measurement-survival-time-brachionus-rotifers-synchronization

Universidad San Sebastian

Research

JoVE Journal

Biology

Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions

8.4K 次观看.  The University of Tokyo. Rotifers are microscopic zooplankton used as models in ecotoxicological and aging studies. Here we provide a protocol for powerful and reproducible measurement of survival time in Brachionus rotifers. Synchronization of culture conditions over several generations is of particular importance because maternal condition affects life history of offspring.

视频: Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes. The transparency of the 
embryos, the genetic resources, and the relative ease of transformation are qualities that make C. elegans an excellent model for early embryogenesis. Laser-based 
confocal microscopy and fluorescently labeled tags allow researchers to follow specific cellular structures and proteins in the developing embryo. For example, 
one can follow specific organelles, such as lysosomes or mitochondria, using fluorescently labeled dyes. These dyes can be delivered to the early embryo by means 
of microinjection into the adult gonad. Also, the localization of specific proteins can be followed using fluorescent protein tags. Examples are presented here 
demonstrating the use of a fluorescent lysosomal dye as well as fluorescently tagged histone and ubiquitin proteins. The labeled histone is used to visualize 
the DNA and thus identify the stage of the cell cycle. GFP-tagged ubiquitin reveals the dynamics of ubiquitinated vesicles in the early embryo. Observations 
of labeled lysosomes and GFP:: ubiquitin can be used to determine if there is colocalization between ubiquitinated vesicles and lysosomes. A technique for 
the microinjection of the lysosomal dye is presented. Techniques for generating transgenenic strains are presented elsewhere (1, 2). For imaging, embryos 
are cut out of adult hermaphrodite nematodes and mounted onto 2% agarose pads followed by time-lapse microscopy on a standard laser scanning confocal 
microscope or a spinning disk confocal microscope. This methodology provides for the high resolution visualization of early embryogenesis.

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

This article describes a technique for the visualization of the early events of embryogenesis in the nematode Caenorhabditis elegans.

时间推移显微镜早期胚胎发育线虫

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes.  The transparency of the 
embryos, the genetic ...

科研

生物学

Basic Caenorhabditis elegans Methods: Synchronization and Observation

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism 1. C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years 2. Discoveries in this nematode have broad implications because many cellular and molecular processes that control animal development are evolutionary conserved 3.
C. elegans life cycle goes through an embryonic stage and four larval stages before animals reach adulthood. Development can take 2 to 4 days depending on the temperature. In each of the stages several characteristic traits can be observed. The knowledge of its complete cell lineage 4,5 together with the deep annotation of its genome turn this nematode into a great model in fields as diverse as the neurobiology 6, aging 7,8, stem cell biology 9 and germ line biology 10. 
An additional feature that makes C. elegans an attractive model to work with is the possibility of obtaining populations of worms synchronized at a specific stage through a relatively easy protocol. The ease of maintaining and propagating this nematode added to the possibility of synchronization provide a powerful tool to obtain large amounts of worms, which can be used for a wide variety of small or high-throughput experiments such as RNAi screens, microarrays, massive sequencing, immunoblot or in situ hybridization, among others. 
Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them.

Basic Caenorhabditis elegans Methods: Synchronization and Observation

The easiness of maintaining and propagating the nematode C. elegans make it a nice model organism to work with. The possibility of synchronizing worms allows the work with a significant amount of subjects at the same developmental stage, what facilitates the study of one particular process in many animals.

基本的<em&gt;线虫</em&gt;方法:同步和观察

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has ...

Formulations for Freeze-drying of Bacteria and Their Influence on Cell Survival

Cellular water can be removed to reversibly inactivate microorganisms to facilitate storage. One such method of removal is freeze-drying, which is considered a gentle dehydration method. To facilitate cell survival during drying, the cells are often formulated beforehand. The formulation forms a matrix that embeds the cells and protects them from various harmful stresses imposed on the cells during freezing and drying. We present here a general method to evaluate the survival rate of cells after freeze-drying and we illustrate it by comparing the results obtained with four different formulations: the disaccharide sucrose, the sucrose derived polymer Ficoll PM400, and the respective polysaccharides hydroxyethyl cellulose (HEC) and hydroxypropyl methyl cellulose (HPMC), on two strains of bacteria, P. putida KT2440 and A. chlorophenolicus A6. In this work we illustrate how to prepare formulations for freeze-drying and how to investigate the mechanisms of cell survival after rehydration by characterizing the formulation using of differential scanning calorimetry (DSC), surface tension measurements, X-ray analysis, and electron microscopy and relating those data to survival rates. The polymers were chosen to get a monomeric structure of the respective polysaccharide resembling sucrose to a varying degrees. Using this method setup we showed that polymers can support cell survival as effectively as disaccharides if certain physical properties of the formulation are controlled1.

Freeze-drying is often an easy and convenient way to obtain dry products of viable bacterial cells. An issue of the process is cell survival. We detail here a procedure to investigate how cell survival during freeze-drying is influenced by the properties of the formulation used.

冷冻干燥细菌及其影响细胞生存的配方

Cellular water can be removed to reversibly inactivate microorganisms to facilitate storage. One such method of removal is freeze-drying, which is ...

Quantitative Measurement of Invadopodia-mediated Extracellular Matrix Proteolysis in Single and Multicellular Contexts

Cellular invasion into local tissues is a process important in development and homeostasis. Malregulated invasion and subsequent cell movement is characteristic of multiple pathological processes, including inflammation, cardiovascular disease and tumor cell metastasis1. Focalized proteolytic degradation of extracellular matrix (ECM) components in the epithelial or endothelial basement membrane is a critical step in initiating cellular invasion. In tumor cells, extensive in vitro analysis has determined that ECM degradation is accomplished by ventral actin-rich membrane protrusive structures termed invadopodia2,3. Invadopodia form in close apposition to the ECM, where they moderate ECM breakdown through the action of matrix metalloproteinases (MMPs). The ability of tumor cells to form invadopodia directly correlates with the ability to invade into local stroma and associated vascular components3. 
Visualization of invadopodia-mediated ECM degradation of cells by fluorescent microscopy using dye-labeled matrix proteins coated onto glass coverslips has emerged as the most prevalent technique for evaluating the degree of matrix proteolysis and cellular invasive potential4,5. Here we describe a version of the standard method for generating fluorescently-labeled glass coverslips utilizing a commercially available Oregon Green-488 gelatin conjugate. This method is easily scaled to rapidly produce large numbers of coated coverslips. We show some of the common microscopic artifacts that are often encountered during this procedure and how these can be avoided. Finally, we describe standardized methods using readily available computer software to allow quantification of labeled gelatin matrix degradation mediated by individual cells and by entire cellular populations. The described procedures provide the ability to accurately and reproducibly monitor invadopodia activity, and can also serve as a platform for evaluating the efficacy of modulating protein expression or testing of anti-invasive compounds on extracellular matrix degradation in single and multicellular settings.

We describe the prototypical method for producing microscope coverslips coated with fluorescent gelatin for visualizing invadopodia-mediated matrix degradation. Computational techniques using available software are presented for quantifying the resultant levels of matrix proteolysis by single cells within a mixed population and for multicellular groups encompassing entire microscopic fields.

定量测量的侵袭伪足介导的细胞外基质蛋白水解单和多细胞的情况下

Cellular invasion into local tissues is a process important in development and homeostasis.  Malregulated invasion and subsequent cell movement is ...

Measurement of Lifespan in Drosophila melanogaster

Aging is a phenomenon that results in steady physiological deterioration in nearly all organisms in which it has been examined, leading to reduced physical performance and increased risk of disease. Individual aging is manifest at the population level as an increase in age-dependent mortality, which is often measured in the laboratory by observing lifespan in large cohorts of age-matched individuals. Experiments that seek to quantify the extent to which genetic or environmental manipulations impact lifespan in simple model organisms have been remarkably successful for understanding the aspects of aging that are conserved across taxa and for inspiring new strategies for extending lifespan and preventing age-associated disease in mammals.
The vinegar fly, Drosophila melanogaster, is an attractive model organism for studying the mechanisms of aging due to its relatively short lifespan, convenient husbandry, and facile genetics. However, demographic measures of aging, including age-specific survival and mortality, are extraordinarily susceptible to even minor variations in experimental design and environment, and the maintenance of strict laboratory practices for the duration of aging experiments is required. These considerations, together with the need to practice careful control of genetic background, are essential for generating robust measurements. Indeed, there are many notable controversies surrounding inference from longevity experiments in yeast, worms, flies and mice that have been traced to environmental or genetic artifacts1-4. In this protocol, we describe a set of procedures that have been optimized over many years of measuring longevity in Drosophila using laboratory vials. We also describe the use of the dLife software, which was developed by our laboratory and is available for download (<a href="http://sitemaker.umich.edu/pletcherlab/software">http://sitemaker.umich.edu/pletcherlab/software</a>). dLife accelerates throughput and promotes good practices by incorporating optimal experimental design, simplifying fly handling and data collection, and standardizing data analysis. We will also discuss the many potential pitfalls in the design, collection, and interpretation of lifespan data, and we provide steps to avoid these dangers.

Measurement of Lifespan in Drosophila melanogaster

Drosophila melanogaster is a powerful model organism for exploring the molecular basis of longevity regulation. This protocol will discuss the steps involved in generating a reproducible, population-based measurement of longevity as well as potential pitfalls and how to avoid them.

寿命测量<em&gt;果蝇</em

Aging is a phenomenon that results in steady physiological deterioration in nearly all organisms in which it has been examined, leading to reduced ...

Measurement of Heme Synthesis Levels in Mammalian Cells

Heme serves as the prosthetic group for a wide variety of proteins known as hemoproteins, such as hemoglobin, myoglobin and cytochromes. It is involved in various molecular and cellular processes such as gene transcription, translation, cell differentiation and cell proliferation. The biosynthesis levels of heme vary across different tissues and cell types and is altered in diseased conditions such as anemia, neuropathy and cancer. This technique uses [4-14C] 5-aminolevulinic acid ([14C] 5-ALA), one of the early precursors in the heme biosynthesis pathway to measure the levels of heme synthesis in mammalian cells. This assay involves incubation of cells with [14C] 5-ALA followed by extraction of heme and measurement of the radioactivity incorporated into heme. This procedure is accurate and quick. This method measures the relative levels of heme biosynthesis rather than the total heme content. To demonstrate the use of this technique the levels of heme biosynthesis were measured in several mammalian cell lines.

Altered intracellular heme levels are associated with common diseases such as cancer. Thus, there is a need to measure heme biosynthesis levels in diverse cells. The goal of this protocol is to provide a fast and sensitive method to measure and compare the levels of heme synthesis in different cells.

中血红素的合成水平在哺乳动物细胞中测量

Heme serves as the prosthetic group for a wide variety of proteins known as hemoproteins, such as hemoglobin, myoglobin and cytochromes. It is involved in ...

Measurement of Metabolic Rate in Drosophila using Respirometry

Metabolic disorders are a frequent problem affecting human health. Therefore, understanding the mechanisms that regulate metabolism is a crucial scientific task. Many disease causing genes in humans have a fly homologue, making Drosophila a good model to study signaling pathways involved in the development of different disorders. Additionally, the tractability of Drosophila simplifies genetic screens to aid in identifying novel therapeutic targets that may regulate metabolism. In order to perform such a screen a simple and fast method to identify changes in the metabolic state of flies is necessary. In general, carbon dioxide production is a good indicator of substrate oxidation and energy expenditure providing information about metabolic state. In this protocol we introduce a simple method to measure CO2 output from flies. This technique can potentially aid in the identification of genetic perturbations affecting metabolic rate.

Measurement of Metabolic Rate in Drosophila using Respirometry

Metabolic disorders are among one of the most common diseases in humans. The genetically tractable model organism D. melanogaster can be used to identify novel genes that regulate metabolism. This paper describes a relatively simple method which allows studying the metabolic rate in flies by measuring their CO2 production.

代谢率的测量<em&gt;果蝇</em&gt;使用呼吸运动

Metabolic disorders are a frequent problem affecting human health. Therefore, understanding the mechanisms that regulate metabolism is a crucial ...

Probe-based Real-time PCR Approaches for Quantitative Measurement of microRNAs

Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that provides an accurate and reproducible analysis. Probe-based chemistry offers the least background fluorescence as compared to other (dye-based) chemistries. Presently, there are several platforms available that use probe-based chemistry to quantitate transcript abundance. qPCR in a 96 well plate is the most routinely used method, however only a maximum of 96 samples or miRNAs can be tested in a single run. This is time-consuming and tedious if a large number of samples/miRNAs are to be analyzed. High-throughput probe-based platforms such as microfluidics (e.g. TaqMan Array Card) and nanofluidics arrays (e.g. OpenArray) offer ease to reproducibly and efficiently detect the abundance of multiple microRNAs in a large number of samples in a short time. Here, we demonstrate the experimental setup and protocol for miRNA quantitation from serum or plasma-EDTA samples, using probe-based chemistry and three different platforms (96 well plate, microfluidics and nanofluidics arrays) offering increasing levels of throughput.

Circulating microRNAs have recently emerged as promising and novel biomarkers for various cancers and other diseases. The goal of this article is to discuss three different probe-based real-time PCR platforms and methods that are available to quantify and determine the abundance of circulating microRNAs.

基于探针实时荧光定量PCR途径的小分子RNA定量检测

Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that ...

Synchronization of Caulobacter Crescentus for Investigation of the Bacterial Cell Cycle

The cell cycle is important for growth, genome replication, and development in all cells. In bacteria, studies of the cell cycle have focused largely on unsynchronized cells making it difficult to order the temporal events required for cell cycle progression, genome replication, and division. Caulobacter crescentus provides an excellent model system for the bacterial cell cycle whereby cells can be rapidly synchronized in a G0 state by density centrifugation. Cell cycle synchronization experiments have been used to establish the molecular events governing chromosome replication and segregation, to map a genetic regulatory network controlling cell cycle progression, and to identify the establishment of polar signaling complexes required for asymmetric cell division. Here we provide a detailed protocol for the rapid synchronization of Caulobacter NA1000 cells. Synchronization can be performed in a large-scale format for gene expression profiling and western blot assays, as well as a small-scale format for microscopy or FACS assays. The rapid synchronizability and high cell yields of Caulobacter make this organism a powerful model system for studies of the bacterial cell cycle.

Synchronization of Caulobacter Crescentus for Investigation of the Bacterial Cell Cycle

Synchronization of bacterial cells is essential for studies of the bacterial cell cycle and development. Caulobacter crescentus is synchronizable through density centrifugation allowing a rapid and powerful tool for studies of the bacterial cell cycle. Here we provide a detailed protocol for the synchronization of Caulobacter cells.

同步<em&gt;新月柄杆菌</em&gt;对细菌细胞周期的研究

The cell cycle is important for growth, genome replication, and development in all cells.  In bacteria, studies of the cell cycle have focused largely on ...

Temporal Tracking of Cell Cycle Progression Using Flow Cytometry without the Need for Synchronization

This protocol describes a method to permit the tracking of cells through the cell cycle without requiring the cells to be synchronized. Achieving cell synchronization can be difficult for many cell systems. Standard practice is to block cell cycle progression at a specific stage and then release the accumulated cells producing a wave of cells progressing through the cycle in unison. However, some cell types find this block toxic resulting in abnormal cell cycling, or even mass death. Bromodeoxyuridine (BrdU) uptake can be used to track the cell cycle stage of individual cells. Cells incorporate this synthetic thymidine analog, while synthesizing new DNA during S phase. By providing BrdU for a brief period it is possible to mark a pool of cells that were in S phase while the BrdU was present. These cells can then be tracked through the remainder of the cell cycle and into the next round of replication, permitting the duration of the cell cycle phases to be determined without the need to induce a potentially toxic cell cycle block. It is also possible to determine and correlate the expression of both internal and external proteins during subsequent stages of the cell cycle. These can be used to further refine the assignment of cell cycle stage or assess effects on other cellular functions such as checkpoint activation or cell death.

This protocol describes the use of bromodeoxyuridine (BrdU) uptake to permit the temporal tracking of cells that were in S phase at a specific point in time. Addition of DNA dyes and antibody labeling facilitates detailed analysis of the fate of the S phase cells at later times.

细胞周期进程的时间跟踪使用流式细胞仪，无需同步

This protocol describes a method to permit the tracking of cells through the cell cycle without requiring the cells to be synchronized. Achieving cell ...