采用Hungate厌氧培养技术分离纯化光合细菌

利用Hungate厌氧培养技术,克服传统分离光合细菌方法的不足,是一种快速、准确、简便地分离纯化光合细菌的方法。     

利用图像识别技术计算薇甘菊锈病的相对病斑面积

【目的】为了定量评估薇甘菊柄锈菌对薇甘菊的防控效果,研发一种基于图像识别技术的高效、准确的薇甘菊叶片相对病斑面积的计算方法。【方法】利用图像识别、网格法、复印称重法3种相对面积的计算方法,分别计算薇甘菊感染柄锈菌后的相对病斑面积,并结合以手动分割的结果作为标准,计算各方法的绝对准确率和绝对误差并作为评价指标,最终对3种相对病斑面积的计算方法开展系统、科学的评估。【结果】与网格法、复印称重法相比,基于超绿和超红算法分割病斑的图像识别方法能够准确、快速地计算出薇甘菊锈病病斑的相对面积,其绝准确率均值达到98%以上,绝对误差率均值仅有1.81%,处理一张4608×3456像素彩色图像只需要45.77 s。【结论】与传统的病斑面积计算方法相比,图像识别技术能够准确、快速地将病斑区域与健康区域分割,并准确地计算相对病斑面积。     

单子叶植物叶片气孔观察方法改良的研究

通过对传统的植物叶片气孔观察方法的改良,建立了一种观察单子叶植物气孔的有效方法。该方法不仅能够分清上下表皮、准确定位,而且简单易行,具有很高的可靠性和稳定性。实验中采用该法可以准确地获得植物叶片的气孔参数,为植物学及生态学的相关研究提供方法上的参考依据。     

荧光定量PCR方法检测白酒发酵过程中Aspergillus tubingensis生物量

【目的】为了更好地分析霉菌在白酒发酵过程中的作用,需要快速准确地测定发酵过程中霉菌生物量的变化,本实验以白酒酿造中常用的塔宾曲霉(Aspergillus tubingensis)为例,建立一套快速准确定量塔宾曲霉生物量的方法。【方法】优化从酒醅中提取基因组的方法,设计和验证专一性引物,建立实时荧光定量PCR(Real-time quantitative PCR)方法,验证方法的有效性并应用于白酒发酵过程中塔宾曲霉生物量的检测。【结果】用原位机械破碎法提取酒醅中总基因组,其DNA的浓度能够达到1.060×105 ng/g酒醅;同时建立了一套快速准确测定固态基质中霉菌生物量的方法,并应用于白酒生产(制曲、堆积发酵和窖池发酵过程)中塔宾曲霉生物量的定量。【结论】实时荧光定量PCR方法能够快速准确地测定固态基质中霉菌的生物量,且检测限较低,对今后的相关研究具有借鉴意义。     

两种简便又较为准确检测SOD酶活性的方法

由于SOD的作用底物极不稳定,至今还未建立统一的检测SOD酶活性的方法,该文介绍了两种既简便又较为准确检测样品SOD酶活性的方法,采用这两种方法可较为准确地测定出不同样品的SOD含量及酶活性。     

DNA序列分析用于常见致病真菌鉴定和分型

随着真菌感染的增多,仅用表型方法鉴定环境中或临床上的致病真菌不足以快速准确地诊断真菌感染疾病,近年来,分子生物学方法因快速、准确而逐步得到应用,其中DNA序列分析已成为鉴定致病真菌到种水平的重要方法。现就DNA序列分析在常见致病真菌分类鉴定及基因分型的应用加以综述。     

单子叶植物叶片气孔观察方法改良的研究

通过对传统的植物叶片气孔观察方法的改良,建立了一种观察单子叶植物气孔的有效方法。该方法不仅能够分清上下表皮、准确定位,而且简单易行,具有很高的可靠性和稳定性。实验中采用该法可以准确地获得植物叶片的气孔参数,为植物学及生态学的相关研究提供方法上的参考依据。     

提高微生物可培养性的方法和措施

目前自然界中只有极少部分微生物能够得到培养,严重阻碍了对微生物生命活动规律的研究和微生物资源的开发。改进传统培养方法,采用新型培养技术,提高微生物可培养性,大量培养自然界中存在的微生物,从而更全面、准确地了解微生物细胞的生命规律、获悉微生物群落中各种微生物之间的动态相互作用和相互协调的规律,对环境微生物工艺进行准确地设计、精细地调控和高效地利用。简要介绍了微生物不可培养的原因,系统总结了有关提高微生物可培养性方法的最新研究进展,提出研究中存在的问题,并阐述了模拟自然环境条件、强调微生物相互关系是提高微生物可培养性的关键。     

广东黑石顶森林群落黄果厚壳桂（Cryptocarya concinna）幼…

黄果厚壳桂幼苗未有准确对应于年龄的外部特征,通过相应样地中幼苗的解析,得出了以幼苗高度和基径对年龄的二元线性回归相对准确地划分幼苗年龄的方法,它优于单纯采用高工级或基径级划分年龄结构的方法,这种方法为非毁坏性的研究现存幼苗的结构提供了依据。     

应用荧光实时定量PCR方法检测重组慢病毒滴度及其感染效率

慢病毒载体已经广泛应用于动物模型中基因治疗的研究和转基因动物的制备．而准确地测定重组慢病毒的滴度和感染效率是其关键步骤．通过荧光实时定量PCR的方法定量分析重组慢病毒的颗粒数以及病毒的活性滴度,并以GFP报告基因的方法作为对照来验证定量PCR方法的准确性．研究结果显示,应用荧光实时定量PCR法与GFP报告基因法测定得到的病毒活性滴度成正相关,而且前者可以更加准确地测定病毒滴度和病毒感染效率．     

Marker-free method for accurate alignment between correlated light,cryo-light,and electron cryo-microscopy data using sample support features

Combining fluorescence microscopy with electron cryo-tomography allows, in principle, spatial localization of tagged macromolecular assemblies and structural features within the cellular environment. To allow precise localization and scale integration between the two disparate imaging modalities, accurate alignment procedures are needed. Here, we describe a marker-free method for aligning images from light or cryo-light fluorescence microscopy and from electron cryo-microscopy that takes advantage of sample support features, namely the holes in the carbon film. We find that the accuracy of this method, as judged by prediction errors of the hole center coordinates, is better than 100?nm.     

基于三维人脸模型及人工测量数据分析现代中国人群面部表型的性别差异

传统体质人类学研究中的样本采集方法是手工测量以及肉眼观察,采集过程中会存在较大的主观性,易产生误差,同时在采集大样本时费时费力。近年来,三维摄像系统被越来越多的应用于人脸分析,其优势是快速高效和准确,并且涵盖了传统测量方法无法精确获取的表型特征信息,可以更加细化地分析人脸表型特征和特征之间的相互关系。本研究探索性地基于三维人脸模型图像,利用曲率和邻域信息的点筛查方法定位了面部的一些关键测量点,建立一套简单、有效、准确率较高的三维人脸模型图像关键点定位方法,能较准确地定位98%以上的眼内角点和鼻尖点,并在此基础上确定了鼻根点、鼻下点、左右鼻翼点和鼻翼外侧最低点等其他面部关键点。并且还提出了在三维人脸模型图像基础上量化部分面部观察类表型特征,如鼻侧深度、鼻根高度、面部扁平度等,尝试性地将这些观察类性状转化为能够测量的性状,建立了一套可以计算的描述方法,具有一定的创新性。本研究还结合三维人脸模型提取数据和人工测量数据,探讨了现代中国人群(以江淮汉族为例)面部表型特征的性别差异,发现大多数面部表型特征在现代中国人群中都存在明显的男女性别差异,鼻侧深度、鼻根高度、面部扁平度的性别差异最为显著,其Z检验的p值均小于0.01。结果显示男性的鼻部整体比女性更大更前凸,而女性的面部更为扁平。     

Rational design of temperature-sensitive alleles using computational structure prediction

Temperature-sensitive (ts) mutations are mutations that exhibit a mutant phenotype at high or low temperatures and a wild-type phenotype at normal temperature. Temperature-sensitive mutants are valuable tools for geneticists, particularly in the study of essential genes. However, finding ts mutations typically relies on generating and screening many thousands of mutations, which is an expensive and labor-intensive process. Here we describe an in silico method that uses Rosetta and machine learning techniques to predict a highly accurate "top 5" list of ts mutations given the structure of a protein of interest. Rosetta is a protein structure prediction and design code, used here to model and score how proteins accommodate point mutations with side-chain and backbone movements. We show that integrating Rosetta relax-derived features with sequence-based features results in accurate temperature-sensitive mutation predictions.     

Prediction of antioxidant proteins using hybrid feature representation method and random forest

Natural antioxidant proteins are mainly found in plants and animals, which interact to eliminate excessive free radicals and protect cells and DNA from damage, prevent and treat some diseases. Therefore, accurate identification of antioxidant proteins is important for the development of new drugs and research of related diseases. This article proposes novel method based on the combination of random forest and hybrid features that can accurately predict antioxidant proteins. Four single feature extraction methods (188D, profile-based Auto-cross covariance (ACC-PSSM), N-gram, and g-gap) and hybrid feature representation methods were used to feature extraction. Three feature selection methods (MRMD, t-SNE, and the optimal feature set selection) were adopted to determine the optimal features. The new hybrid feature vectors derived by combining 188D with the other three features all have indicators ranging from 0.9550 to 0.9990. The novel method showed better performance compared with the other methods.     

A computer programme for the calculation of radioactivity data from liquid-scintillation counters fitted with external standards

1. A method for transferring data from liquid-scintillation counters to automatic punched-card read-out is described. 2. A method of calibration of an external standard is presented that supplies sufficient information for the correction of quenched data by computer. 3. A computer programme in FORTRAN IV is described that calculates the data from one isotope, or two isotopes counted simultaneously, and that incorporates features for examining the reproducibility of the input data. 4. With the methods described, quench correction of samples containing either (3)H or (14)C was accurate until samples were quenched 70%. When the two isotopes were both present in one sample and counted simultaneously, the correction was accurate until the samples were quenched 60%. When quenching was greater than either 70 or 60% respectively, its correction was still possible but with slightly diminished accuracy and with greater variability.     

A recursion model for cellular production/assembly systems

This article presents an efficient algorithm for applying the recursion modeling approach to describe the transient operation of cellular production/assembly systems that incorporate features such as finite buffers, job-shop routing, lot sequencing, and material handling. Tests evaluate the approximation method relative to number of machines at a station, capacity of input/output buffers, degree of balance among station processing times, and sequencing rule. Furthermore, the method is demonstrated in application to a hypothetical industrial setting that involves the assembly of electronic circuit cards in a facility composed of several cells. All tests indicate that the method gives accurate estimates of transient performance within reasonable runtime. In comparison with earlier recursion models, this research incorporates a number of new features (see list above), improves the accuracy of approximation, and facilitates implementation with a new, more efficient algorithm.