우리는 그의 도움을 Microarray 핵심 시설에 크레이그 폴 감사합니다. 이 작품은 IMAT 프로그램에서 NIH / NCI 부여 # CA118591에 의해 지원되었다. SLD는 재정 지원을위한 펜실베니아 공간 부여 컨소시엄 활동을 인정한다. 이 책자는 또한 펜실베니아 주립 대학 재료 연구소 나노 제작 네트워크와 국립 과학 재단 (National Science Foundation) 공동 계약 코넬 대학과 번호 0335765, 국가 나노기술 인프라 네트워크에 의해 지원되었다.

<ol>
	<li>Kulbachinskiy, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+selection+of+aptamers+to+protein+targets.">Methods for selection of aptamers to protein targets.</a> Biochemistry (Moscow). 72, 1505-1518 (2006).</li><li>Mairal, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aptamers:+molecular+tools+for+analytical+applications.">Aptamers: molecular tools for analytical applications.</a> Anal Bioanal Chem. 390, 989-1007 (2008).</li><li>Stoltenburg, R., Reinemann, C., Strehlitz, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SELEX+--+A+(r)evolutionary+method+to+generate+high-affinity+nucleic+acid+ligands.">SELEX -- A (r)evolutionary method to generate high-affinity nucleic acid ligands.</a> Biomolec Engineering. 24, 381-403 (2007).</li><li>Que-Gewirth, N. S., Sullenger, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+therapy+progress+and+prospects:+RNA+aptamers.">Gene therapy progress and prospects: RNA aptamers.</a> Gene Ther. 14, 283-2891 (2007).</li><li>Cowperthwaite, M. C., Ellington, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioinformatic+analysis+of+the+contribution+of+primer+sequences+to+aptamer+structures.">Bioinformatic analysis of the contribution of primer sequences to aptamer structures.</a> J Mol Evol. 67, 95-102 (2008).</li><li>Shtatland, T., Gill, S. C., Javornik, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+of+Escherichia+coli+RNA+with+bacteriophage+MS2+coat+protein:+genomic+SELEX.">Interactions of Escherichia coli RNA with bacteriophage MS2 coat protein: genomic SELEX.</a> Nucleic Acids Res. 28, E93-E93 (2000).</li><li>Jarosch, F., Buchner, K., Klussmann, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+selection+using+a+dual+RNA+library+that+allows+primerless+selection.">In vitro selection using a dual RNA library that allows primerless selection.</a> Nucleic Acids Res. 34, E86-E86 (2006).</li><li>Vater, A., Jarosch, F., Buchner, K., Klussmann, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Short+bioactive+Spiegelmers+to+migraine-associated+calcitonin+gene-related+peptide+rapidly+identified+by+a+novel+approach:+tailored-SELEX.">Short bioactive Spiegelmers to migraine-associated calcitonin gene-related peptide rapidly identified by a novel approach: tailored-SELEX.</a> Nucleic Acids Res. 31, E130-E130 (2003).</li><li>Wen, J. D., Gray, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selection+of+genomic+sequences+that+bind+tightly+to+Ff+gene+5+protein:+primer-free+genomic+SELEX.">Selection of genomic sequences that bind tightly to Ff gene 5 protein: primer-free genomic SELEX.</a> Nucleic Acids Res. 32, E182-E182 (2004).</li><li>Musheev, M. U., Krylov, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selection+of+aptamers+by+systematic+evolution+of+ligands+by+exponential+enrichment:+addressing+the+polymerase+chain+reaction+issue.">Selection of aptamers by systematic evolution of ligands by exponential enrichment: addressing the polymerase chain reaction issue.</a> Anal Chim Acta. 564, 91-916 (2006).</li><li>Pan, W. H., Clawson, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primer-free+aptamer+selection+using+a+random+DNA+library.">Primer-free aptamer selection using a random DNA library.</a> Methods Mol Biol. , (2009).</li><li>Pan, W., Xin, P., Clawson, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimal-Primer+and+Primer-Free+SELEX+Protocols+for+Selection+of+Aptamers+from+Random+DNA+Libraries.">Minimal-Primer and Primer-Free SELEX Protocols for Selection of Aptamers from Random DNA Libraries.</a> BioTechniques. 44, 351-360 (2008).</li><li>Nicewarner-Pena, S., Freeman, G., Reiss, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Submicrometer+metallic+barcodes.">Submicrometer metallic barcodes.</a> Science. 294, 137-141 (2001).</li><li>JC, H. u. l. t. e. e. n., CR, M. a. r. t. i. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+general+template-based+method+for+the+preparation+of+nanomaterials.">A general template-based method for the preparation of nanomaterials.</a> J Materials Chem. 7, 1075-1087 (1997).</li></ol>

관심 없음 충돌 선언하지 않습니다.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Tris-HCl</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>HotMaster TAQ DNA Polymerase</td>
<td>&nbsp;</td>
<td>5-Prime</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>dNTP Mix</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Acrylamide</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>UltraPure 10X TBE Buffer</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ammonium Persulfate</td>
<td>&nbsp;</td>
<td>Bio-Rad</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>TEMED</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>PhiX174 DNA/Hinf I DNA Marker</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ethidium Bromide</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>&alpha;-32P-dCTP</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Phenol:ChCl3:IAA</td>
<td>&nbsp;</td>
<td>Ambion</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>NaCl</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ethanol</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Restriction Enzymes</td>
<td>&nbsp;</td>
<td>NEB</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Urea</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Photographic Film</td>
<td>&nbsp;</td>
<td>ECE Scientific</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>PBS</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>CaCl2</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>MgCl2</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ni-NTA Agarose Beads</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Polypropylene Column</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>NaHPO4</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>NaAc</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Detroit-551 cells</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>SK-MEL-31 cells</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>MEM</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>TrypLE Express</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>T4 DNA Ligase</td>
<td>&nbsp;</td>
<td>NEB</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Dimethyl Sulfoxide</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Sp6 RNA Polymerase</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>RNase-Free DNase I</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>RNase Inhibitor</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>SensiScript Reverse Transcriptase</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>pCR-2.1-TOPO Vector</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>DH5&alpha; Compotent Cells</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Plasmid Mini Kit</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Vector NTI</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>T4 Polynucleotide Kinase</td>
<td>&nbsp;</td>
<td>NEB</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>&gamma;-32P-ATP</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

primer-free aptamer selection using a random dna library

Aptamers는 항체 1 비교 동질성과 목표에 바인딩할 수 고도로 구조화된 oligonucleotides (DNA 또는 RNA)입니다. 그들은 작은 분자에서 단백질 및 기타 macromolecules 2-4로 대상의 다양한 인식 지수 농축 (SELEX)의 리간드의 체계적인 진화라는 체외 선정 과정에서를 통해 식별됩니다. Aptamers 잘 생체내 진단 및 / 또는 치료 응용 프로그램에 적합 한 특성을 가지고 있습니다 : 좋은 특이성과 친화력 게다가, 쉽게 합성되며, 더 엄격한 가공 조건을 살아남기, 그들은 제대로 immunogenic하고, 그들의 비교적 작은 크기의 손쉬운 보급률이 발생할 수 있습니다 티슈. 그들은 일반적으로 양쪽에 ~ 40 NT 긴 무작위 지역 플러스 ~ 20 NT의 고정 뇌관 사이트와 핵산 라이브러리에서 선택한 있기 때문에 표준 SELEX 과정을 통해 확인할 수 있습니다 Aptamers는 일반적으로, ~ 80 세포핵 (NT)를 구성. 생물 정보학의 접근 방식은 고정 시퀀스 선택 5시 이후엔 aptamer 구조에 크게 기여하지 않는 것이 좋습니다하지만 고정 뇌관 시퀀스는, 따라서 ~ 거의 라이브러리 시퀀스의 50 %를 구성 수 있으며, 따라서 긍정적 으로든 부정적 으로든 선정 과정 3 aptamers의 신분을 손상시킬 수 . 이러한 잠재적인 문제를 해결하기 위해, 뇌관 시퀀스는 상호 보완 oligonucleotides에 의해 차단된 또는 SELEX 6 라운드 동안 다른 시퀀스의 미드웨이로 전환하거나, 그들은 6-9 NT 7, 8 손질했습니다되었습니다. 웬 앤드 그레이 9, 입문서없는 게놈 SELEX 방법을 설계하는 뇌관 시퀀스 완전히 선택하기 전에 라이브러리에서 제거되었습니다 다음 선택한 게놈 조각의 증폭을 허용하는 생성되었습니다. 그러나 기술을 채용하기 위해 고유의 게놈 라이브러리 구축되어야, 어떤이 제한 다양성을 보유하고, 선택의 라운드 후 재생은 선형 reamplification 단계에 의존합니다. 또한, 고효율 파티션을 사용하여 고정 뇌관 시퀀스로 인한 문제를 회피하기위한 노력은 PCR 증폭 10에 관한 문제 충족하고 있습니다. 우리는 크게 SELEX 절차를 단순화하고 효율적으로 프라이머 - 간섭 문제 11, 12를 제거하는 입문서 무료 (PF) 선택 방법을 개발했습니다. 프로토콜은 간단한 방식으로 작동합니다. 라이브러리의 중앙 무작위 지역 관​​계없는 측면 순서없이 정화하고 적당한 대상 (정화 단백질이나 세포 라인과 같은 복잡한 혼합물로 예를 들면)에 바인딩됩니다. 그러면 바운드 시퀀스가​​ 얻은 측면 시퀀스와 상봉하고, 선택된 하위 라이브러리를 생성하기 위해 다시 증폭됩니다. 예를 들어, 우리가 S100B, 흑색증의 단백질 마커에 aptamers을 선택했습니다. 선택의 몇 라운드 후 10 -8 M 범위를, 그리고 우리는 aptamers가 샌드위치 바인딩 형식에서 효과적으로 기능 것을 입증 - 바인딩 assays는 10 -7에서 KD S을 보여주었다.

Watch this Scientific Journal Video about Primer-Free Aptamer Selection Using A Random DNA Library at JoVE.com

Primer-Free Aptamer Selection Using A Random DNA Library

SELEX의 프로토콜 설정에서 임의의 라이브러리 영역을 측면 고정 프라이머 시퀀스를 요구 바운드 리간드의 재생을 필요로 각각의 선택 여러 라운드를 구성. 이러한 고정 프라이머 시퀀스는 선택 프로세스 (잘못된 반응과 제외)을 방해할 수 있습니다. 여기 입문서없는 프로토콜을 제시한다.

랜덤 DNA 라이브러리를 사용하여 뇌관 - 무료 Aptamer 선택

Aptamers are highly structured oligonucleotides (DNA or RNA) that can bind to targets with affinities comparable to antibodies 1. They are identified ...

primer-free-aptamer-selection-using-a-random-dna-library

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

24.6K 조회수.  Pennsylvania State University. SELEX의 프로토콜 설정에서 임의의 라이브러리 영역을 측면 고정 프라이머 시퀀스를 요구 바운드 리간드의 재생을 필요로 각각의 선택 여러 라운드를 구성. 이러한 고정 프라이머 시퀀스는 선택 프로세스 (잘못된 반응과 제외)을 방해할 수 있습니다. 여기 입문서없는 프로토콜을 제시한다.

비디오: Primer-Free Aptamer Selection Using A Random DNA Library

Large Insert Environmental Genomic Library Production

The vast majority of microbes in nature currently remain inaccessible to traditional cultivation methods. Over the past decade, culture-independent environmental genomic (i.e. metagenomic) approaches have emerged, enabling researchers to bridge this cultivation gap by capturing the genetic content of indigenous microbial communities directly from the environment. To this end, genomic DNA libraries are constructed using standard albeit artful laboratory cloning techniques. Here we describe the construction of a large insert environmental genomic fosmid library with DNA derived from the vertical depth continuum of a seasonally hypoxic fjord. This protocol is directly linked to a series of connected protocols including coastal marine water sampling [1], large volume filtration of microbial biomass [2] and a DNA extraction and purification protocol [3]. At the outset, high quality genomic DNA is end-repaired with the creation of 5 -phosphorylated blunt ends. End-repaired DNA is subjected to pulsed-field gel electrophoresis (PFGE) for size selection and gel extraction is performed to recover DNA fragments between 30 and 60 thousand base pairs (Kb) in length. Size selected DNA is purified away from the PFGE gel matrix and ligated to the phosphatase-treated blunt-end fosmid CopyControl vector pCC1 (EPICENTRE <a href="http://www.epibio.com/item.asp?ID=385">http://www.epibio.com/item.asp?ID=385</a>). Linear concatemers of pCC1 and insert DNA are subsequently headfull packaged into phage particles by lambda terminase, with subsequent infection of phage-resistant E. coli cells. Successfully transduced clones are recovered on LB agar plates under antibiotic selection and archived in 384-well plate format using an automated colony picking robot (Qpix2, GENETIX). The current protocol draws from various sources including the CopyControl Fosmid Library Production Kit from EPICENTRE and the published works of multiple research groups [4-7]. Each step is presented with best practice in mind. Whenever possible we highlight subtleties in execution to improve overall quality and efficiency of library production. The whole process of fosmid library production and automated colony picking takes at least 7-10 days as there are many incubation steps included. However, there are several stopping points possible which are mentioned within the protocol.

Construction of a fosmid library with environmental genomic DNA isolated from the vertical depth continuum of a seasonally hypoxic fjord is described. The resulting clone library is picked into 384-well plates and archived for downstream sequencing and functional screening by the application of an automated colony picking system.

대형 삽입 환경 게놈 라이브러리 제작

The vast majority of microbes in nature currently remain inaccessible to traditional cultivation methods. Over the past decade, culture-independent ...

연구

생물학

Direct Observation of Enzymes Replicating DNA Using a Single-molecule DNA Stretching Assay

We describe a method for observing real time replication of individual DNA molecules mediated by proteins of the bacteriophage replication system. Linearized &lambda; DNA is modified to have a biotin on the end of one strand, and a digoxigenin moiety on the other end of the same strand. The biotinylated end is attached to a functionalized glass coverslip and the digoxigeninated end to a small bead. The assembly of these DNA-bead tethers on the surface of a flow cell allows a laminar flow to be applied to exert a drag force on the bead. As a result, the DNA is stretched close to and parallel to the surface of the coverslip at a force that is determined by the flow rate (Figure 1). The length of the DNA is measured by monitoring the position of the bead. Length differences between single- and double-stranded DNA are utilized to obtain real-time information on the activity of the replication proteins at the fork. Measuring the position of the bead allows precise determination of the rates and processivities of DNA unwinding and polymerization (Figure 2).

We describe a method for observing real time replication of individual DNA molecules mediated by proteins of the bacteriophage replication system.

효소 복제 DNA의 직접 관찰 어세을 스트레칭 단일 분자 DNA를 사용하여

We describe a method for observing real time replication of individual DNA molecules mediated by proteins of the bacteriophage replication system. ...

DNA Stable-Isotope Probing (DNA-SIP)

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and nutrients into cellular biomass. As such, this cultivation-independent technique has been an important methodology for assigning metabolic function to the diverse communities inhabiting a wide range of terrestrial and aquatic environments. Following the incubation of an environmental sample with stable-isotope labelled compounds, extracted nucleic acid is subjected to density gradient ultracentrifugation and subsequent gradient fractionation to separate nucleic acids of differing densities. Purification of DNA from cesium chloride retrieves labelled and unlabelled DNA for subsequent molecular characterization (e.g. fingerprinting, microarrays, clone libraries, metagenomics). This JoVE video protocol provides visual step-by-step explanations of the protocol for density gradient ultracentrifugation, gradient fractionation and recovery of labelled DNA. The protocol also includes sample SIP data and highlights important tips and cautions that must be considered to ensure a successful DNA-SIP analysis.

DNA Stable-Isotope Probing DNA-SIP

DNA stable-isotope probing is a cultivation-independent method to identify and characterize active communities of microorganisms that are capable of utilizing specific substrates. Assimilation of substrate enriched in heavy isotope leads to incorporation of labelled atoms into microbial biomass. Density gradient ultracentrifugation retrieves labelled DNA for downstream molecular analyses.

DNA 안정 - 동위 원소 (DNA - SIP) 탐색

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and ...

Single Particle Electron Microscopy Reconstruction of the Exosome Complex Using the Random Conical Tilt Method

Single particle electron microscopy (EM) reconstruction has recently become a popular tool to get the three-dimensional (3D) structure of large macromolecular complexes. Compared to X-ray crystallography, it has some unique advantages. First, single particle EM reconstruction does not need to crystallize the protein sample, which is the bottleneck in X-ray crystallography, especially for large macromolecular complexes. Secondly, it does not need large amounts of protein samples. Compared with milligrams of proteins necessary for crystallization, single particle EM reconstruction only needs several micro-liters of protein solution at nano-molar concentrations, using the negative staining EM method. However, despite a few macromolecular assemblies with high symmetry, single particle EM is limited at relatively low resolution (lower than 1 nm resolution) for many specimens especially those without symmetry. This technique is also limited by the size of the molecules under study, i.e. 100 kDa for negatively stained specimens and 300 kDa for frozen-hydrated specimens in general.
For a new sample of unknown structure, we generally use a heavy metal solution to embed the molecules by negative staining. The specimen is then examined in a transmission electron microscope to take two-dimensional (2D) micrographs of the molecules. Ideally, the protein molecules have a homogeneous 3D structure but exhibit different orientations in the micrographs. These micrographs are digitized and processed in computers as "single particles". Using two-dimensional alignment and classification techniques, homogenous molecules in the same views are clustered into classes. Their averages enhance the signal of the molecule's 2D shapes. After we assign the particles with the proper relative orientation (Euler angles), we will be able to reconstruct the 2D particle images into a 3D virtual volume.
In single particle 3D reconstruction, an essential step is to correctly assign the proper orientation of each single particle. There are several methods to assign the view for each particle, including the angular reconstitution1 and random conical tilt (RCT) method2. In this protocol, we describe our practice in getting the 3D reconstruction of yeast exosome complex using negative staining EM and RCT. It should be noted that our protocol of electron microscopy and image processing follows the basic principle of RCT but is not the only way to perform the method. We first describe how to embed the protein sample into a layer of Uranyl-Formate with a thickness comparable to the protein size, using a holey carbon grid covered with a layer of continuous thin carbon film. Then the specimen is inserted into a transmission electron microscope to collect untilted (0-degree) and tilted (55-degree) pairs of micrographs that will be used later for processing and obtaining an initial 3D model of the yeast exosome. To this end, we perform RCT and then refine the initial 3D model by using the projection matching refinement method3.

This article describes a standard method to get a three-dimensional (3D) reconstruction of biological macromolecules using negative staining electron microscopy (EM). In this protocol, we explain how to get the 3D structure of the Saccharomyces cerevisiae exosome complex at medium resolution using the random conical tilt reconstruction method (RCT).

랜덤 코니컬 틸트 메서드를 사용하여 Exosome 단지의 단일 입자의 전자 현미경의 재건

Single particle electron microscopy (EM) reconstruction has recently become a popular tool to get the three-dimensional (3D) structure of large ...

Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library

The Target ID Library is designed to assist in discovery and identification of microRNA (miRNA) targets. The Target ID Library is a plasmid-based, genome-wide cDNA library cloned into the 3'UTR downstream from the dual-selection fusion protein, thymidine kinase-zeocin (TKzeo). The first round of selection is for stable transformants, followed with introduction of a miRNA of interest, and finally, selecting for cDNAs containing the miRNA's target. Selected cDNAs are identified by sequencing (see Figure 1-3 for Target ID Library Workflow and details).
To ensure broad coverage of the human transcriptome, Target ID Library cDNAs were generated via oligo-dT priming using a pool of total RNA prepared from multiple human tissues and cell lines. Resulting cDNA range from 0.5 to 4 kb, with an average size of 1.2 kb, and were cloned into the p3&#900;TKzeo dual-selection plasmid (see Figure 4 for plasmid map). The gene targets represented in the library can be found on the Sigma-Aldrich webpage. Results from Illumina sequencing (Table 3), show that the library includes 16,922 of the 21,518 unique genes in UCSC RefGene (79%), or 14,000 genes with 10 or more reads (66%).

The Target ID Library is a plasmid-based, genome-wide collection of cloned cDNA used to identify miRNA targets. Here we demonstrate its use and application.

선교 대상 아이디 라이브러리를 사용하여 miRNA 목표를위한 게놈 - 와이드 스크린

The Target ID Library is designed to assist in discovery and identification of microRNA (miRNA) targets. The Target ID Library is a plasmid-based, ...

Quantitative Analysis of Random Migration of Cells Using Time-lapse Video Microscopy

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During directional migration, cells move rapidly in response to an extracellular chemotactic signal, or in response to intrinsic cues 3 provided by the basic motility machinery. Random migration occurs when a cell possesses low intrinsic directionality, allowing the cells to explore their local environment.
Cell migration is a complex process, in the initial response cell undergoes polarization and extends protrusions in the direction of migration 2. Traditional methods to measure migration such as the Boyden chamber migration assay is an easy method to measure chemotaxis in vitro, which allows measuring migration as an end point result. However, this approach neither allows measurement of individual migration parameters, nor does it allow to visualization of morphological changes that cell undergoes during migration.
Here, we present a method that allows us to monitor migrating cells in real time using video - time lapse microscopy. Since cell migration and invasion are hallmarks of cancer, this method will be applicable in studying cancer cell migration and invasion in vitro. Random migration of platelets has been considered as one of the parameters of platelet function 4, hence this method could also be helpful in studying platelet functions. This assay has the advantage of being rapid, reliable, reproducible, and does not require optimization of cell numbers. In order to maintain physiologically suitable conditions for cells, the microscope is equipped with CO2 supply and temperature thermostat. Cell movement is monitored by taking pictures using a camera fitted to the microscope at regular intervals. Cell migration can be calculated by measuring average speed and average displacement, which is calculated by Slidebook software.

This method allows monitoring of cells in real time and quantitative measurements of different cell migration parameters such as speed, displacement, and velocity. Unlike the traditional methods, this real time approach is not based on endpoint quantitative migration measurements; instead it allows monitoring and calculating different parameters continuously.

시간 경과 비디오 현미경을 이용한 세포의 무작위 마이 그 레이션의 정량 분석

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During ...

Improving the Success Rate of Protein Crystallization by Random Microseed Matrix Screening

Random microseed matrix screening (rMMS) is a protein crystallization technique in which seed crystals are added to random screens. By increasing the likelihood that crystals will grow in the metastable zone of a protein's phase diagram, extra crystallization leads are often obtained, the quality of crystals produced may be increased, and a good supply of crystals for data collection and soaking experiments is provided. Here we describe a general method for rMMS that may be applied to either sitting drop or hanging drop vapor diffusion experiments, established either by hand or using liquid handling robotics, in 96-well or 24-well tray format.

Here we describe a general method for random microseed matrix screening. This technique is shown to significantly increase the success rate of protein crystallization screening experiments, reduce the need for optimization, and provide a reliable supply of crystals for data collection and ligand-soaking experiments.

임의 Microseed 매트릭스 심사에 의해 단백질 결정화의 성공률을 향상

Random microseed matrix screening  (rMMS) is a protein crystallization technique in which seed crystals are added  to random screens. By increasing the ...

A Protocol for Phage Display and Affinity Selection Using Recombinant Protein Baits

Using recombinant phage as a scaffold to present various protein portions encoded by a directionally cloned cDNA library to immobilized bait molecules is an efficient means to discover interactions. The technique has largely been used to discover protein-protein interactions but the bait molecule to be challenged need not be restricted to proteins. The protocol presented here has been optimized to allow a modest number of baits to be screened in replicates to maximize the identification of independent clones presenting the same protein. This permits greater confidence that interacting proteins identified are legitimate interactors of the bait molecule. Monitoring the phage titer after each affinity selection round provides information on how the affinity selection is progressing as well as on the efficacy of negative controls. One means of titering the phage, and how and what to prepare in advance to allow this process to progress as efficiently as possible, is presented. Attributes of amplicons retrieved following isolation of independent plaque are highlighted that can be used to ascertain how well the affinity selection has progressed. Trouble shooting techniques to minimize false positives or to bypass persistently recovered phage are explained. Means of reducing viral contamination flare up are discussed.

Phage display is a powerful technique to capture proteins or protein moieties that interact with an immobilized molecule of interest. Once a decision of the type of phage cDNA library to create and screen has been made, the protocol described here permits efficient affinity selection leading to identification of interactors.

재조합 단백질의 미끼를 사용 파지 디스플레이와 궁합 선택을위한 프로토콜

Using  recombinant phage as a scaffold to present various protein portions encoded by  a directionally cloned cDNA library to immobilized bait molecules ...

Real-time Imaging of Single Engineered RNA Transcripts in Living Cells Using Ratiometric Bimolecular Beacons

The growing realization that both the temporal and spatial regulation of gene expression can have important consequences on cell function has led to the development of diverse techniques to visualize individual RNA transcripts in single living cells. One promising technique that has recently been described utilizes an oligonucleotide-based optical probe, ratiometric bimolecular beacon (RBMB), to detect RNA transcripts that were engineered to contain at least four tandem repeats of the RBMB target sequence in the 3&#8217;-untranslated region. RBMBs are specifically designed to emit a bright fluorescent signal upon hybridization to complementary RNA, but otherwise remain quenched. The use of a synthetic probe in this approach allows photostable, red-shifted, and highly emissive organic dyes to be used for imaging. Binding of multiple RBMBs to the engineered RNA transcripts results in discrete fluorescence spots when viewed under a wide-field fluorescent microscope. Consequently, the movement of individual RNA transcripts can be readily visualized in real-time by taking a time series of fluorescent images. Here we describe the preparation and purification of RBMBs, delivery into cells by microporation and live-cell imaging of single RNA transcripts.

Ratiometric bimolecular beacons (RBMBs) can be used to image single engineered RNA transcripts in living cells. Here, we describe the preparation and purification of RBMBs, delivery of RBMBs into cells by microporation and fluorescent imaging of single RNA transcripts in real-time.

비례 생체 분자 비콘을 사용하여 살아있는 세포의 단일 엔지니어링 RNA 성적 증명서의 실시간 영상

The growing realization that both the temporal and spatial regulation of gene expression can have important consequences on cell function has led to the ...

Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology

Until recently, astronaut blood samples were collected in-flight, transported to earth on the Space Shuttle, and analyzed in terrestrial laboratories. If humans are to travel beyond low Earth orbit, a transition towards space-ready, point-of-care (POC) testing is required. Such testing needs to be comprehensive, easy to perform in a reduced-gravity environment, and unaffected by the stresses of launch and spaceflight. Countless POC devices have been developed to mimic laboratory scale counterparts, but most have narrow applications and few have demonstrable use in an in-flight, reduced-gravity environment. In fact, demonstrations of biomedical diagnostics in reduced gravity are limited altogether, making component choice and certain logistical challenges difficult to approach when seeking to test new technology. To help fill the void, we are presenting a modular method for the construction and operation of a prototype blood diagnostic device and its associated parabolic flight test rig that meet the standards for flight-testing onboard a parabolic flight, reduced-gravity aircraft. The method first focuses on rig assembly for in-flight, reduced-gravity testing of a flow cytometer and a companion microfluidic mixing chip. Components are adaptable to other designs and some custom components, such as a microvolume sample loader and the micromixer may be of particular interest. The method then shifts focus to flight preparation, by offering guidelines and suggestions to prepare for a successful flight test with regard to user training, development of a standard operating procedure (SOP), and other issues. Finally, in-flight experimental procedures specific to our demonstrations are described.

Spaceflight blood diagnostics need innovation. Few demonstrations have been published illustrating in-flight, reduced-gravity health diagnostic technology. Here we present a method for construction and operation of a parabolic flight test rig for a prototype point-of-care flow-cytometry design, with components and preparation strategies adaptable to other setups.

프로토 타입 소형 흐름 사이토와 동반자 미세 유체 혼합 기술의 감소 - 중력 환경 하드웨어 데모

Until recently, astronaut blood samples were collected in-flight, transported to earth on the Space Shuttle, and analyzed in terrestrial laboratories. If ...