우리는 텍스트를 코멘트에 대한 Blelloch 실험실을 감사드립니다. 이 작품은에서 NIH (K08 NS48118 및 R01 NS057221), 재생 의학의 캘리포니아 공과 대학 (CIRM) (시드 부여 RS1 - 00161, 뉴 학부 수상 RN2 - 00906)와 퓨 자선 트러스트에서 RB하는 자금에 의해 및 FM을 지원했습니다 Wissenschaftlich Urologische Gesellschaft EV.

<ol>
	<li>Mitchell, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+microRNAs+as+stable+blood-based+markers+for+cancer+detection.">Circulating microRNAs as stable blood-based markers for cancer detection.</a> Proc Natl Acad Sci U S A. 105, 10513-10518 (2008).</li><li>Tang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=220-plex+microRNA+expression+profile+of+a+single+cell.">220-plex microRNA expression profile of a single cell.</a> Nat Protoc. 1, 1154-1159 (2006).</li><li>Gertsenstein, M., Vintersten, K., Behringer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Manipulating the Mouse Embryo: A Laboratory Manual. 3, 644-645 (2003).</li><li>Suh, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MicroRNA+function+is+globally+suppressed+in+mouse+oocytes+and+early+embryos.">MicroRNA function is globally suppressed in mouse oocytes and early embryos.</a> Curr Biol. 20, 271-277 (2010).</li><li>Babiarz, J. E., Ruby, J. G., Wang, Y., Bartel, D. P., Blelloch, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+ES+cells+express+endogenous+shRNAs,+siRNAs,+and+other+Microprocessor-independent,+Dicer-dependent+small+RNAs.">Mouse ES cells express endogenous shRNAs, siRNAs, and other Microprocessor-independent, Dicer-dependent small RNAs.</a> Genes Dev. 22, 2773-2785 (2008).</li><li>Babiarz, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+RNAs:+their+biogenesis,+regulation+and+function+in+embryonic+stem+cells.">Small RNAs: their biogenesis, regulation and function in embryonic stem cells.</a> StemBook. , (2009).</li><li>Friedman, R. C., Farh, K. K., Burge, C. B., Bartel, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Most+mammalian+mRNAs+are+conserved+targets+of+microRNAs.">Most mammalian mRNAs are conserved targets of microRNAs.</a> Genome Res. 19, 92-105 (2008).</li><li>Wang, Y., Medvid, R., Melton, C., Jaenisch, R., Blelloch, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DGCR8+is+essential+for+microRNA+biogenesis+and+silencing+of+embryonic+stem+cell+self-renewal.">DGCR8 is essential for microRNA biogenesis and silencing of embryonic stem cell self-renewal.</a> Nat Genet. 39, 380-385 (2007).</li><li>Kanellopoulou, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dicer-deficient+mouse+embryonic+stem+cells+are+defective+in+differentiation+and+centromeric+silencing.">Dicer-deficient mouse embryonic stem cells are defective in differentiation and centromeric silencing.</a> Genes Dev. 19, 489-501 (2005).</li><li>Thomson, J. M., Parker, J., Perou, C. M., Hammond, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+custom+microarray+platform+for+analysis+of+microRNA+gene+expression.">A custom microarray platform for analysis of microRNA gene expression.</a> Nat Methods. 1, 47-53 (2004).</li><li>Moltzahn, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+based+multiplex+qRT-PCR+identifies+diagnostic+and+prognostic+microRNA+signatures+in+sera+of+prostate+cancer+patients.">Microfluidic based multiplex qRT-PCR identifies diagnostic and prognostic microRNA signatures in sera of prostate cancer patients.</a> Cancer Res. 71, 550-560 (2011).</li><li>Mestdagh, P. <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+and+universal+method+for+microRNA+RT-qPCR+data+normalization.">A novel and universal method for microRNA RT-qPCR data normalization.</a> Genome Biol. 10, R64-R64 (2009).</li></ol>

앨런 미러는 플루 회사의 직원입니다. 그렇지 않으면, 우리는 공개하지 재정적 이해 관계가 없습니다.

miRNAs가 짧고 (18-24 세포핵), 비 코딩 모두 약화 메신저 RNAS (mRNA)와 억제 자신의 번역에 의해 게시 - transcriptionally 유전자 발현을 조절 RNAS을 6. 인간 유전자 중 최소한 한 세 번째 보존 포함 사실 miRNA 자신의 3&#39;UTR에 바인딩 - 사이트 및 pluripotency, 증식 및 apoptosis에 대한 유전자 miRNAs의 뚜렷하지 상호 작용은 세포의 운명 결정, 조직 항상성 및 암 같은 질병에 중요한 기여를 제안합니다. 6,7 따라서 정확한 microRNA 표현 프로파일은 확장의 아르 관심. qRT - PCR의 miRNA 발현 프로 파일링 프로토콜 2 출판 멀티 플렉스를 테스트하려면 우리는 부정적인 컨트롤로 작은 RNA 결함 mESC를 사용합니다. / - - DGCR8 - / - 주사위 놀이를하는 사람 중에 세포는 모든 정식 microRNAs의 결함입니다. 세포는 정식이 아닌 canoncial 모두 micoRNAs 부족 8,9 / - - DGCR8 MES 대 야생 유형의 수준을 비교 세포를, 우리는 몇 가지 10 microRNAs는 야생 형 세포 11 발견되지 않은 표현으로 정확성 부족을 밝혀. 일부는 심지어 녹아웃 세포 (그림 3A)에 비해 낮은 표현 수준을 보여주었다. 우리는 정확성의 부족은 singleplex RT - 부량 전에 연속 2 멀티 플렉스 단계의 대규모 뇌관 이월 (RT 및 Pre - PCR)에 의한지도 모른다고 가상. 그러나, 멀티 플렉스 사전 증폭은 RNA의 시작 농도가 제한 특히, 신호의 강도를 향상시키기 위해 필요합니다. / - - 원시 polyacrylamide의 젤 (그림 2)에서 크기를 선택하여 primers에서 사전 PCR 제품을 멀리 정화함으로써, 우리는 Dgcr8 모두에서 더 많은 microRNAs과 거짓 긍정적인 신호의 손실을 감지하여 정확성에 상당한 개선을 보여주는 수 있으며, 주사위 놀이를하는 사람 - / - 또한 배경 (인물 3A 및 3B) 희귀 Dgcr8 독립 / 주사위 놀이를하는 사람 종속 작은 RNAS (그림 3B) 11의 적절한 분류에 허용되는 변경 qRT - PCR 방식. 따라서 멀리 사전 PCR 제품의 과도한 primers를 정화하기 위해 추가 단계는 대형 멀티 플렉스 프라이머를 사용하면 예제마다 집합 특히, 명확하게 유리한 것입니다. 사전 증폭 사이클의 최적의 번호는 입력 RNA의 농도에 의해 결정됩니다. 하지 미만 또는 균형 overamplify는 특정 실험의 세부 사항으로 안내한다. 이상 천 알려진 microRNAs를 통해 표준의 사용 384 잘 복수의 샘플을 비교 특히 접시가 광범위한 microRNA 프로 파일링 최적되지 않을 수 있습니다. 플루 동적 배열 IFC는 nanoliter 규모 (6.7 NL)에서 하나의 실험 (9,216 반응)에서 96 가지 microRNAs에 대해 96 개인 샘플까지 테스트, pipetting 단계와 필요한 화학 상당한 감소와 수 있습니다. 각 실행에 대한 분석 소프트웨어는 증폭 곡선, 색상 코드 열지도 및 사이클 임계값 값 (CT)를 제공합니다. 동시 대규모 프로 파일링은 실험 차이를 줄여 작은 RNA 컨트롤을 사용하게 다른 정상화 전략을 밖 수행 의미 표현 값 정상화에 대한 수 있습니다. 12 미리 할당된 TaqMan 프로브와 함께 상용 384 잘 플랫폼에 비해, 사용자 정의 만든 프라이머 세트와 높은 처리량 프로 파일링 플랫폼의 조합은 높은 실험 유연성을 제공합니다. 동적 배열 플랫폼과 함께 최적화된 멀티 플렉스 qRT - PCR 방법은 성공적으로 우리는 동시에 384 miRNA (그림 4)의 수준에서 변경 48 전립선 암 환자 세라를 화면과 컨트롤의 증가 (즉, 합성 microRNAs)없이 데이터를 정상화 수있었습니다. 11 샘플 준비의 프로 파일링 결과 단계의 증가에도 불구하고, 설명하는 방식도 제한 시작 소재, 시간 및 miRNA 발현 수준에 대한 큰 샘플 세트를 프로필에 비용 효율 높은 처리량 방법입니다.

high throughput microrna profiling: optimized multiplex qrt-pcr at nanoliter scale on the fluidigm dynamic arraytm ifcs

개발, 조직 homoeostasis과 질병을 기본 핵심 프로세스에서 miRNAs의 광범위한 참여가 연구와 제약 공동체 간의 급증 관심되었다. miRNAs을 연구하기 위해서는 microRNA 수준의 부량가 정확하고 안정적​​인 것을 중요합니다. 작은 RNA 부족한 마우스 배아 줄기 세포 (mESC)에 야생 형 비교하여, 우리는 이전의 출판 멀티 플렉스 qRT - PCR 기술의 정확성과 견고의 부족을 공개했다. 여기, 우리는 극적으로 기술의 정확성과 견고을 증가 singleplex 실시간 감지, 이전 이전 다중화 단계에서 과도한 primers 멀리 정화를 포함하여 최적의 방법을 설명합니다. nanoliter 볼륨에서 microfluidic 칩 기술을 수행하는 방법에 또한, 우리가 설명 크게 시약 비용 절감 및 시간 효율적인 높은 처리량 miRNA 발현 프로 파일링을 수 있습니다.

Watch this Scientific Journal Video about High Throughput MicroRNA Profiling: Optimized Multiplex qRT-PCR at Nanoliter Scale on the Fluidigm Dynamic ArrayTM IFCs at JoVE.com

High Throughput MicroRNA Profiling: Optimized Multiplex qRT-PCR at Nanoliter Scale on the Fluidigm Dynamic ArrayTM IFCs

여기 샘플 제한된 양의 작업 특히, microRNA (miRNA) 표현 수준에 대해 비용과 시간 효율 높은 처리량 검사 도구로 microfluidic 플랫폼와 함께 최적화된 멀티 플렉스 반전 transcriptase 정량 PCR (qRT - PCR) 프로토콜을 설명합니다.

높은 처리량 MicroRNA의 프로파일 : 최적 멀티 플렉스 플루 동적 ArrayTM의 IFCs에 Nanoliter의 규모 qRT - PCR

The broad involvement of miRNAs in critical processes underlying development, tissue homoeostasis and disease has led to a surging interest among the ...

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Research

JoVE Journal

Bioengineering

20.4K 조회수.  University of California San Francisco. 여기 샘플 제한된 양의 작업 특히, microRNA (miRNA) 표현 수준에 대해 비용과 시간 효율 높은 처리량 검사 도구로 microfluidic 플랫폼와 함께 최적화된 멀티 플렉스 반전 transcriptase 정량 PCR (qRT - PCR) 프로토콜을 설명합니다.

비디오: High Throughput MicroRNA Profiling: Optimized Multiplex qRT-PCR at Nanoliter Scale on the Fluidigm Dynamic ArrayTM IFCs

Cell-based Calcium Assay for Medium to High Throughput Screening of TRP Channel Functions using FlexStation 3

The Molecular Devices' FlexStation 3 is a benchtop multi-mode microplate reader capable of automated fluorescence measurement in multi-well plates. It is ideal for medium- to high-throughput screens in academic settings. It has an integrated fluid transfer module equipped with a multi-channel pipetter and the machine reads one column at a time to monitor fluorescence changes of a variety of fluorescent reagents. For example, FlexStation 3 has been used to study the function of Ca2+-permeable ion channels and G-protein coupled receptors by measuring the changes of intracellular free Ca2+ levels. Transient receptor potential (TRP) channels are a large family of nonselective cation channels that play important roles in many physiological and pathophysiological functions. Most of the TRP channels are calcium permeable and induce calcium influx upon activation. In this video, we demonstrate the application of FlexStation 3 to study the pharmacological profile of the TRPA1 channel, a molecular sensor for numerous noxious stimuli. HEK293 cells transiently or stably expressing human TRPA1 channels, grown in 96-well plates, are loaded with a Ca2+-sensitive fluorescent dye, Fluo-4, and real-time fluorescence changes in these cells are measured before and during the application of a TRPA1 agonist using the FLEX mode of the FlexStation 3. The effect of a putative TRPA1 antagonist was also examined. Data are transferred from the SoftMax Pro software to construct concentration-response relationships of TRPA1 activators and inhibitors.

This video provides a detailed protocol for studying the pharmacological profile of human TRPA1 channels using FlexStation 3. The protocol covers details of cell preparation, dye loading and operation of the microplate reader, FlexStation 3.

FlexStation 3을 사용 TRP 채널 기능의 높은 처리량 검사하는 매체를위한 셀 기반의 칼슘 분석

The Molecular Devices' FlexStation 3 is a benchtop multi-mode microplate reader capable of automated fluorescence measurement in multi-well plates.  It is ...

연구

생체공학

Candida albicans Biofilm Chip (CaBChip) for High-throughput Antifungal Drug Screening

Candida albicans remains the main etiological agent of candidiasis, which currently represents the fourth most common nosocomial bloodstream infection in US hospitals1. These opportunistic infections pose a growing threat for an increasing number of compromised individuals, and carry unacceptably high mortality rates. This is in part due to the limited arsenal of antifungal drugs, but also to the emergence of resistance against the most commonly used antifungal agents. Further complicating treatment is the fact that a majority of manifestations of candidiasis are associated with the formation of biofilms, and cells within these biofilms show increased levels of resistance to most clinically-used antifungal agents2. Here we describe the development of a high-density microarray that consists of C. albicans nano-biofilms, which we have named CaBChip3. Briefly, a robotic microarrayer is used to print yeast cells of C. albicans onto a solid substrate. During printing, the yeast cells are enclosed in a three dimensional matrix using a volume as low as 50 nL and immobilized on a glass substrate with a suitable coating. After initial printing, the slides are incubated at 37 &deg;C for 24 hours to allow for biofilm development. During this period the spots grow into fully developed "nano-biofilms" that display typical structural and phenotypic characteristics associated with mature C. albicans biofilms (i.e. morphological complexity, three dimensional architecture and drug resistance)4. Overall, the CaBChip is composed of ~750 equivalent and spatially distinct biofilms; with the additional advantage that multiple chips can be printed and processed simultaneously. Cell viability is estimated by measuring the fluorescent intensity of FUN1 metabolic stain using a microarray scanner. This fungal chip is ideally suited for use in true high-throughput screening for antifungal drug discovery. Compared to current standards (i.e. the 96-well microtiter plate model of biofilm formation5), the main advantages of the fungal biofilm chip are automation, miniaturization, savings in amount and cost of reagents and analyses time, as well as the elimination of labor intensive steps. We believe that such chip will significantly speed up the antifungal drug discovery process.

Candida albicans Biofilm Chip CaBChip for High-throughput Antifungal Drug Screening

We have developed a high-density microarray platform consisting of 3D nano-biofilms of C. albicans called CaBChip. The susceptibility profile of drugs tested on a CaBChip is comparable to the conventional 96-well plate model, suggesting that the fungal chip is ideally suited for true high-throughput screening of antifungal drugs.

높은 처리량 Antifungal 약물 검사를위한 칸디다 albicans Biofilm 칩 (CA BChip)

Candida  albicans remains the main etiological agent of candidiasis, which  currently represents the fourth most common nosocomial bloodstream infection ...

High-throughput Protein Expression Generator Using a Microfluidic Platform

Rapidly increasing fields, such as systems biology, require the development and implementation of new technologies, enabling high-throughput and high-fidelity measurements of large systems. Microfluidics promises to fulfill many of these requirements, such as performing high-throughput screening experiments on-chip, encompassing biochemical, biophysical, and cell-based assays1. Since the early days of microfluidics devices, this field has drastically evolved, leading to the development of microfluidic large-scale integration2,3. This technology allows for the integration of thousands of micromechanical valves on a single device with a postage-sized footprint (Figure 1). We have developed a high-throughput microfluidic platform for generating in vitro expression of protein arrays (Figure 2) named PING (Protein Interaction Network Generator). These arrays can serve as a template for many experiments such as protein-protein 4, protein-RNA5 or protein-DNA6 interactions.
The device consist of thousands of reaction chambers, which are individually programmed using a microarrayer. Aligning of these printed microarrays to microfluidics devices programs each chamber with a single spot eliminating potential contamination or cross-reactivity Moreover, generating microarrays using standard microarray spotting techniques is also very modular, allowing for the arraying of proteins7, DNA8, small molecules, and even colloidal suspensions. The potential impact of microfluidics on biological sciences is significant. A number of microfluidics based assays have already provided novel insights into the structure and function of biological systems, and the field of microfluidics will continue to impact biology.

We present a microfluidic approach for the expression of protein arrays. The device consists of thousands of reaction chambers controlled by micro-mechanical valves. The microfluidic device is mated to a microarray-printed gene library. These genes are then transcribed and translated on-chip, resulting in a protein array ready for experimental use.

마이크로 유체 플랫폼을 사용하여 높은 처리량 단백질 표현 생성기

Rapidly increasing fields, such as systems biology, require the development and implementation of new technologies, enabling high-throughput and ...

Synthetic Spider Silk Production on a Laboratory Scale

As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next generation engineering materials for biomimicry that rival the best manmade and natural materials. Since the collection of large quantities of natural spider silk is impractical, synthetic silk production has the ability to provide scientists with access to an unlimited supply of threads. Therefore, if the spinning process can be streamlined and perfected, artificial spider fibers have the potential use for a broad range of applications ranging from body armor, surgical sutures, ropes and cables, tires, strings for musical instruments, and composites for aviation and aerospace technology. In order to advance the synthetic silk production process and to yield fibers that display low variance in their material properties from spin to spin, we developed a wet-spinning protocol that integrates expression of recombinant spider silk proteins in bacteria, purification and concentration of the proteins, followed by fiber extrusion and a mechanical post-spin treatment. This is the first visual representation that reveals a step-by-step process to spin and analyze artificial silk fibers on a laboratory scale. It also provides details to minimize the introduction of variability among fibers spun from the same spinning dope. Collectively, these methods will propel the process of artificial silk production, leading to higher quality fibers that surpass natural spider silks.

Despite the outstanding mechanical and biochemical properties of spider silks, this material cannot be harvested in large quantities by conventional means. Here we describe an efficient strategy to spin artificial spider silk fibers, which is an important process for investigators studying spider silk production and their use as next-generation biomaterials.

실험실 규모의 합성 거미의 실크 생산

As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation ...

Cloning and Large-Scale Production of High-Capacity Adenoviral Vectors Based on the Human Adenovirus Type 5

High-capacity adenoviral vectors (HCAdV) devoid of all viral coding sequences represent one of the most advanced gene delivery vectors due to their high packaging capacity (up to 35 kb), low immunogenicity, and low toxicity. However, for many laboratories the use of HCAdV is hampered by the complicated procedure for vector genome construction and virus production. Here, a detailed protocol for efficient cloning and production of HCAdV based on the plasmid pAdFTC containing the HCAdV genome is described. The construction of HCAdV genomes is based on a cloning vector system utilizing homing endonucleases (I-CeuI and PI-SceI). Any gene of interest of up to 14 kb can be subcloned into the shuttle vector pHM5, which contains a multiple cloning site flanked by I-CeuI and PI-SceI. After I-CeuI and PI-SceI-mediated release of the transgene from the shuttle vector the transgene can be inserted into the HCAdV cloning vector pAdFTC. Because of the large size of the pAdFTC plasmid and the long recognition sites of the used enzymes associated with strong DNA binding, careful handling of the cloning fragments is needed. For virus production, the HCAdV genome is released by NotI digest and transfected into a HEK293 based producer cell line stably expressing Cre recombinase. To provide all adenoviral genes for adenovirus amplification, co-infection with a helper virus containing a packing signal flanked by loxP sites is required. Pre-amplification of the vector is performed in producer cells grown on surfaces and large-scale amplification of the vector is conducted in spinner flasks with producer cells grown in suspension. For virus purification, two ultracentrifugation steps based on cesium chloride gradients are performed followed by dialysis. Here tips, tricks, and shortcuts developed over the past years working with this HCAdV vector system are presented.

A protocol for generation of high-capacity adenoviral vectors lacking all viral coding sequences is presented. Cloning of transgenes contained in the vector genome is based on homing endonucleases. Virus amplification in producer cells grown as adherent cells and in suspension relies on a helper virus providing viral genes in trans.

인간 아데노 바이러스 유형 5를 기반으로 대용량 아데노 바이러스 벡터의 클로닝 및 대규모 생산

High-capacity adenoviral vectors (HCAdV) devoid of all viral coding sequences represent one of the most advanced gene delivery vectors due to their high ...

Describing a Transcription Factor Dependent Regulation of the MicroRNA Transcriptome

While the transcription regulation of protein coding genes was extensively studied, little is known on how transcription factors are involved in transcription of non-coding RNAs, specifically of microRNAs. Here, we propose a strategy to study the potential role of transcription factor in regulating transcription of microRNAs using publically available data, computational resources and high throughput data. We use the H3K4me3 epigenetic signature to identify microRNA promoters and chromatin immunoprecipitation (ChIP)-sequencing data from the ENCODE project to identify microRNA promoters that are enriched with transcription factor binding sites. By transfecting cells of interest with shRNA targeting a transcription factor of interest and subjecting the cells to microRNA array, we study the effect of this transcription factor on the microRNA transcriptome. As an illustrative example we use our study on the effect of STAT3 on the microRNA transcriptome of chronic lymphocytic leukemia (CLL) cells.

Herein we propose a strategy to study the effect of a transcription factor of interest on the microRNA transcriptome using publically available data, computational resources and high throughput data from microRNA arrays after transfecting cells with small hairpin (sh)RNA targeting a transcription factor of interest.

마이크로 RNA 전 사체 (Transcriptome)의 전사 인자 종속 규정을 설명

While the transcription regulation of protein coding genes was extensively studied, little is known on how transcription factors are involved in ...

Easy and Accurate Mechano-profiling on Micropost Arrays

Cell culture substrates with integrated flexible microposts enable a user to study the mechanical interactions between cells and their immediate surroundings. Particularly, cell-substrate interactions are the main interest. Today micropost arrays are a well-characterized and established method with a broad range of applications that have been published over the last decade. However, there seems to be a reservation among biologists to adapt the technique due to the lengthy and challenging process of micropost manufacture along with the lack of easily approachable software for analyzing images of cells interacting with microposts. 
The force read-out from microposts is surprisingly easy. A micropost acts like a spring with the cell ideally attached at its tip. Depending on size a cell applies force from its cytoskeleton through one or multiple focal adhesion points to the micropost, thus deflecting the micropost. The amount of deflection correlates directly to the applied force in direction and in magnitude. The number of microposts covered by a cell and the post deflection patterns are characteristic and allow determination of values like force per post and many biologically relevant parameters that allow &#8220;mechano-profiling&#8221; of cell phenotypes.
A convenient method for mechano-profiling is described here combining the first generation of ready-to-use commercially available microposts with an in-house developed software package that is now accessible to all researchers. As a demonstration of typical application, single images of bone cancer cells were taken in bright-field microscopy for mechano-profiling of cell line models of metastasis. This combination of commercial traction force sensors and open source software for analysis allows for the first time a rapid implementation of the micropost array technique into routine lab work done by non-expert users. Furthermore, a robust and streamlined analysis process enables a user to analyze a large number of micropost images in a highly time-efficient manner.

Described are protocols for quantifying mechanical interactions between adherent cells and microstructured substrates. These interactions are closely linked to essential cell behaviors including migration, proliferation, differentiation, and apoptosis. The protocols present an open-source image analysis software called MechProfiler, which enables determination of involved forces for each micropost.

Micropost 배열에 쉽고 정확한 - 기계 프로파일

Cell culture substrates with integrated flexible microposts enable a user to study the mechanical interactions between cells and their immediate ...

Using Tomoauto: A Protocol for High-throughput Automated Cryo-electron Tomography

Cryo-electron tomography (Cryo-ET) is a powerful three-dimensional (3-D) imaging technique for visualizing macromolecular complexes in their native context at a molecular level. The technique involves initially preserving the sample in its native state by rapidly freezing the specimen in vitreous ice, then collecting a series of micrographs from different angles at high magnification, and finally computationally reconstructing a 3-D density map. The frozen-hydrated specimen is extremely sensitive to the electron beam and so micrographs are collected at very low electron doses to limit the radiation damage. As a result, the raw cryo-tomogram has a very low signal to noise ratio characterized by an intrinsically noisy image. To better visualize subjects of interest, conventional imaging analysis and sub-tomogram averaging in which sub-tomograms of the subject are extracted from the initial tomogram and aligned and averaged are utilized to improve both contrast and resolution. Large datasets of tilt-series are essential to understanding and resolving the complexes at different states, conditions, or mutations as well as obtaining a large enough collection of sub-tomograms for averaging and classification. Collecting and processing this data can be a major obstacle preventing further analysis. Here we describe a high-throughput cryo-ET protocol based on a computer-controlled 300kV cryo-electron microscope, a direct detection device (DDD) camera and a highly effective, semi-automated image-processing pipeline software wrapper library tomoauto developed in-house. This protocol has been effectively utilized to visualize the intact type III secretion system (T3SS) in Shigella flexneri minicells. It can be applicable to any project suitable for cryo-ET.

We present a protocol on how to utilize high-throughput cryo-electron tomography to determine high resolution in situ structures of molecular machines. The protocol permits large amounts of data to be processed, avoids common bottlenecks and reduces resource downtime, allowing the user to focus on important biological questions.

Tomoauto 사용 : 프로토콜 높은 처리량 자동화 된 곳을 알아내는 - 전자 단층 촬영을 위해

Cryo-electron tomography (Cryo-ET) is a powerful three-dimensional (3-D) imaging technique for visualizing macromolecular complexes in their native ...

A High-throughput Cell Microarray Platform for Correlative Analysis of Cell Differentiation and Traction Forces

Microfabricated cellular microarrays, which consist of contact-printed combinations of biomolecules on an elastic hydrogel surface, provide a tightly controlled, high-throughput engineered system for measuring the impact of arrayed biochemical signals on cell differentiation. Recent efforts using cell microarrays have demonstrated their utility for combinatorial studies in which many microenvironmental factors are presented in parallel. However, these efforts have focused primarily on investigating the effects of biochemical cues on cell responses. Here, we present a cell microarray platform with tunable material properties for evaluating both cell differentiation by immunofluorescence and biomechanical cell&#8211;substrate interactions by traction force microscopy. To do so, we have developed two different formats utilizing polyacrylamide hydrogels of varying Young&#39;s modulus fabricated on either microscope slides or glass-bottom Petri dishes. We provide best practices and troubleshooting for the fabrication of microarrays on these hydrogel substrates, the subsequent cell culture on microarrays, and the acquisition of data. This platform is well-suited for use in investigations of biological processes for which both biochemical (e.g., extracellular matrix composition) and biophysical (e.g., substrate stiffness) cues may play significant, intersecting roles.

Cell differentiation is regulated by a host of microenvironmental factors, including both matrix composition and substrate material properties. We describe here a technique utilizing cell microarrays in conjunction with traction force microscopy to evaluate both cell differentiation and biomechanical cell&#8211;substrate interactions as a function of microenvironmental context.

세포 분화 및 견인 힘의 상관 관계 분석을위한 높은 처리량 세포 마이크로 어레이 플랫폼

Microfabricated cellular microarrays, which consist of contact-printed combinations of biomolecules on an elastic hydrogel surface, provide a tightly ...

Power Input Measurements in Stirred Bioreactors at Laboratory Scale

The power input in stirred bioreactors is an important scaling-up parameter and can be measured through the torque that acts on the impeller shaft during rotation. However, the experimental determination of the power input in small-scale vessels is still challenging due to relatively high friction losses inside typically used bushings, bearings and/or shaft seals and the accuracy of commercially available torque meters. Thus, only limited data for small-scale bioreactors, in particular single-use systems, is available in the literature, making comparisons among different single-use systems and their conventional counterparts difficult.
This manuscript provides a protocol on how to measure power inputs in benchtop scale bioreactors over a wide range of turbulence conditions, which can be described by the dimensionless Reynolds number (Re). The aforementioned friction losses are effectively reduced by the use of an air bearing. The procedure on how to set up, conduct and evaluate a torque-based power input measurement, with special focus on cell culture typical agitation conditions with low to moderate turbulence (100 &#60; Re &#60; 2&#183;104), is described in detail. The power input of several multi-use and single-use bioreactors is provided by the dimensionless power number (also called Newton number, P0), which is determined to be in the range of P0 &#8776; 0.3 and P0 &#8776; 4.5 for the maximum Reynolds numbers in the different bioreactors.

The power input in stirred bioreactors can be measured through the torque that acts on the impeller shaft during rotation. This manuscript describes how an air bearing can be used to effectively reduce friction losses observed in mechanical seals and improve the accuracy of power input measurements in small-scale vessels.

The power input in stirred bioreactors is an important scaling-up parameter and can be measured through the torque that acts on the impeller shaft during ...