Qrt Pcr Delta Ct

Understanding qRT-PCR ΔCt: A Comprehensive Guide for Accurate Gene Expression Analysis

Unlocking the secrets of gene expression is crucial across numerous scientific disciplines, from medical research to agricultural biotechnology. Quantitative real-time polymerase chain reaction (qRT-PCR) is a cornerstone technique for this purpose, providing precise measurements of RNA levels. However, interpreting the raw data requires understanding a key metric: the ΔCt (delta Ct) value. This comprehensive guide will demystify qRT-PCR ΔCt, explaining its calculation, significance, and limitations, equipping you with the knowledge to confidently analyze your gene expression experiments. We’ll explore the underlying principles, practical applications, and common pitfalls to avoid for accurate and reliable results.

What is qRT-PCR and Why Use ΔCt?

qRT-PCR measures the amount of a specific RNA molecule in a sample. It relies on the amplification of cDNA (complementary DNA) synthesized from the RNA template. The amplification process is monitored in real-time, allowing for quantification of the initial RNA abundance. However, simply comparing the cycle threshold (Ct) values between different samples isn’t sufficient for accurate gene expression analysis. This is where the ΔCt comes in. The Ct value represents the number of cycles it takes for the fluorescence signal to cross a defined threshold, indicating sufficient amplification of the target gene. A lower Ct value signifies higher initial RNA abundance. However, variations in RNA extraction efficiency, cDNA synthesis, and qRT-PCR reaction efficiency can affect the Ct values between samples. To correct for these variations, we use a reference gene (housekeeping gene) and calculate the ΔCt.

Calculating ΔCt: A Step-by-Step Guide

The ΔCt value represents the difference between the Ct value of your target gene and the Ct value of your reference gene. The reference gene is a stably expressed gene, chosen because its expression level remains relatively constant across different samples. Popular choices include GAPDH, β-actin, and 18S rRNA. The formula is straightforward:

ΔCt = Ct (target gene) - Ct (reference gene)

For instance, if the Ct value for your target gene is 20 and the Ct value for your reference gene is 15, then your ΔCt is 20 - 15 = 5. This calculation is performed for each sample individually.

Interpreting ΔCt Values: What Do They Tell Us?

The ΔCt value provides a normalized measure of gene expression. A lower ΔCt indicates higher relative expression of your target gene compared to the reference gene. Conversely, a higher ΔCt suggests lower relative expression. The ΔCt value itself doesn't represent an absolute quantity of RNA but rather a relative comparison within your experiment. Therefore, ΔCt values are only meaningful when compared within the same experiment, under the same conditions. Direct comparisons between experiments performed on different days or with different batches of reagents are generally unreliable.

Advanced Applications: ΔΔCt Method for Fold Change Calculation

To compare gene expression between different experimental groups (e.g., treated vs. untreated cells), the ΔΔCt method is used. This method extends the ΔCt calculation by comparing the ΔCt values of your experimental group to a control group.

ΔΔCt = ΔCt (experimental group) - ΔCt (control group)

The fold change in gene expression is then calculated using the following formula:

Fold Change = 2^(-ΔΔCt)

A fold change greater than 1 indicates upregulation of the target gene in the experimental group compared to the control group, while a fold change less than 1 signifies downregulation. This calculation provides a more meaningful interpretation of your results, accounting for variations between different experimental groups.

Common Pitfalls and Troubleshooting

Accurate ΔCt analysis requires meticulous attention to detail. Several factors can impact the results:

Reference gene selection: Choosing an inappropriate reference gene can lead to inaccurate results. It's crucial to validate the stability of your reference gene across your experimental conditions using appropriate software or statistical methods.

RNA quality: Poor-quality RNA can lead to inaccurate Ct values. Ensure your RNA is intact and free of degradation.

Primer design: Inefficient or non-specific primers can affect amplification efficiency and lead to inaccurate results.

qRT-PCR reaction conditions: Inconsistent reaction conditions can introduce variability between samples. Maintain consistent temperature, reagent concentrations, and reaction volumes.

Data analysis: Proper statistical analysis is necessary to determine significant differences in gene expression. Avoid overinterpreting small differences in ΔCt values.

Practical Applications of qRT-PCR ΔCt Analysis

The applications of qRT-PCR ΔCt analysis are vast and span various fields:

Cancer research: Studying gene expression changes in cancerous cells compared to healthy cells.

Infectious disease research: Monitoring viral load and host response during infection.

Drug discovery: Assessing the effects of drug treatments on gene expression.

Agricultural biotechnology: Analyzing gene expression in genetically modified crops.

Environmental science: Studying the impact of environmental factors on gene expression in organisms.

Ebook Outline: Mastering qRT-PCR ΔCt Analysis

Title: Mastering qRT-PCR ΔCt Analysis: From Theory to Practical Application

Outline:

Introduction: What is qRT-PCR and why use ΔCt? The importance of accurate gene expression analysis.

Chapter 1: Understanding qRT-PCR Fundamentals: Detailed explanation of the technique, including cDNA synthesis, primer design, and reaction optimization.

Chapter 2: ΔCt Calculation and Interpretation: Step-by-step guide to ΔCt calculation, interpretation of results, and common pitfalls.

Chapter 3: Advanced Applications: The ΔΔCt Method: In-depth explanation of the ΔΔCt method for comparing gene expression between groups.

Chapter 4: Reference Gene Selection and Validation: Strategies for selecting and validating appropriate reference genes.

Chapter 5: Troubleshooting and Quality Control: Addressing common issues and troubleshooting strategies for accurate results.

Chapter 6: Data Analysis and Interpretation: Statistical methods for data analysis and interpretation of results.

Chapter 7: Practical Applications and Case Studies: Examples of qRT-PCR ΔCt analysis in various fields.

Conclusion: Summary of key concepts and future directions.

Detailed explanation of each outline point:

(These would be expanded upon significantly in the full ebook, with figures, tables, and examples. Below are brief overviews.)

Introduction: This section would provide a captivating introduction to the importance of gene expression analysis in modern biological research, highlighting the role of qRT-PCR as a gold-standard technique. It sets the stage for the subsequent chapters by explaining the need for ΔCt analysis in achieving accurate and reliable results.

Chapter 1: Understanding qRT-PCR Fundamentals: This chapter delves into the technical aspects of qRT-PCR, explaining the process from RNA extraction to data acquisition. It covers crucial details such as cDNA synthesis methods, primer design principles, and the optimization of PCR reaction conditions.

Chapter 2: ΔCt Calculation and Interpretation: A detailed explanation of the ΔCt calculation, including examples and practical illustrations. It explains the significance of the ΔCt value in relative gene expression analysis and discusses the limitations of direct Ct value comparisons.

Chapter 3: Advanced Applications: The ΔΔCt Method: This chapter focuses on the ΔΔCt method, explaining how it enables comparative analysis of gene expression between different experimental groups. It demonstrates how to calculate fold change and interpret the results in a biologically meaningful context.

Chapter 4: Reference Gene Selection and Validation: This chapter explores the crucial role of reference gene selection and introduces methods for validating their stability across experimental conditions. It discusses various statistical approaches for selecting appropriate reference genes.

Chapter 5: Troubleshooting and Quality Control: This chapter identifies and addresses common pitfalls encountered in qRT-PCR experiments, providing practical troubleshooting tips and guidelines for ensuring high-quality data.

Chapter 6: Data Analysis and Interpretation: This chapter explores the importance of proper statistical analysis in interpreting qRT-PCR results. It covers relevant statistical tests and methods for visualizing and presenting data effectively.

Chapter 7: Practical Applications and Case Studies: This section provides real-world examples of qRT-PCR ΔCt applications across diverse fields, highlighting the versatility and power of this technique.

Conclusion: This section summarizes the key concepts covered in the ebook, reinforcing the importance of accurate ΔCt analysis for reliable gene expression studies and pointing towards future advancements in the field.

FAQs

1. What is the difference between Ct and ΔCt? Ct is the cycle threshold, indicating the number of cycles needed for amplification to reach a detectable level. ΔCt normalizes gene expression by subtracting the Ct of a reference gene from the Ct of the target gene.

2. Why is a reference gene necessary for ΔCt calculation? A reference gene provides an internal control to account for variations in RNA quality, cDNA synthesis, and qRT-PCR efficiency between samples.

3. How do I choose an appropriate reference gene? Select a gene with stable expression across your experimental conditions. Use software or statistical methods to validate the stability of your chosen reference gene.

4. What does a negative ΔCt value mean? The target gene’s expression is lower than the reference gene’s expression.

5. What are the limitations of the ΔCt method? ΔCt values are relative, not absolute. They are only meaningful within the same experiment.

6. Can I compare ΔCt values from different experiments? No, ΔCt values should only be compared within the same experiment, under the same conditions.

7. What is the significance of fold change in ΔΔCt analysis? Fold change indicates the upregulation or downregulation of the target gene in the experimental group compared to the control group.

8. How do I interpret a fold change value of 2? This means the target gene is upregulated two-fold in the experimental group compared to the control group.

9. What software can I use for qRT-PCR data analysis? Several software packages are available, including Bio-Rad CFX Maestro, Applied Biosystems QuantStudio, and various open-source options.

Related Articles

1. Optimizing qRT-PCR Primer Design: This article explores the crucial aspects of designing efficient and specific primers for qRT-PCR experiments.

2. Reference Gene Selection in qRT-PCR: A detailed guide to choosing and validating appropriate reference genes for accurate gene expression normalization.

3. Advanced qRT-PCR Data Analysis Techniques: An exploration of sophisticated statistical methods and software tools for advanced qRT-PCR data analysis.

4. Troubleshooting Common qRT-PCR Issues: A comprehensive guide to identifying and resolving common problems encountered during qRT-PCR experiments.

5. The Impact of RNA Quality on qRT-PCR Results: A discussion on the importance of RNA quality and methods for ensuring high-quality RNA for accurate gene expression measurements.

6. Applications of qRT-PCR in Cancer Research: This article explores the use of qRT-PCR in studying gene expression changes in cancer cells and their implications for diagnosis and treatment.

7. qRT-PCR in Infectious Disease Research: This focuses on using qRT-PCR for detecting and quantifying viral or bacterial loads in clinical samples.

8. Quantitative PCR: A Comprehensive Overview: A broad introduction to quantitative PCR techniques, including real-time PCR (qPCR) and digital PCR (dPCR).

9. Understanding Standard Curves in qRT-PCR: This article delves into the significance of standard curves in absolute quantification of gene expression using qRT-PCR.


  qrt pcr delta ct: Gene Quantification Francois Ferre, 2012-12-06 Geneticists and molecular biologists have been interested in quantifying genes and their products for many years and for various reasons (Bishop, 1974). Early molecular methods were based on molecular hybridization, and were devised shortly after Marmur and Doty (1961) first showed that denaturation of the double helix could be reversed - that the process of molecular reassociation was exquisitely sequence dependent. Gillespie and Spiegelman (1965) developed a way of using the method to titrate the number of copies of a probe within a target sequence in which the target sequence was fixed to a membrane support prior to hybridization with the probe - typically a RNA. Thus, this was a precursor to many of the methods still in use, and indeed under development, today. Early examples of the application of these methods included the measurement of the copy numbers in gene families such as the ribosomal genes and the immunoglo bulin family. Amplification of genes in tumors and in response to drug treatment was discovered by this method. In the same period, methods were invented for estimating gene num bers based on the kinetics of the reassociation process - the so-called Cot analysis. This method, which exploits the dependence of the rate of reassociation on the concentration of the two strands, revealed the presence of repeated sequences in the DNA of higher eukaryotes (Britten and Kohne, 1968). An adaptation to RNA, Rot analysis (Melli and Bishop, 1969), was used to measure the abundance of RNAs in a mixed population.
  qrt pcr delta ct: Real-time PCR M Tevfik Dorak, 2007-02-08 With a variety of detection chemistries, an increasing number of platforms, multiple choices for analytical methods and the jargon emerging along with these developments, real-time PCR is facing the risk of becoming an intimidating method, especially for beginners. Real-time PCR provides the basics, explains how they are exploited to run a real-time PCR assay, how the assays are run and where these assays are informative in real life. It addresses the most practical aspects of the techniques with the emphasis on 'how to do it in the laboratory'. Keeping with the spirit of the Advanced Methods Series, most chapters provide an experimental protocol as an example of a specific assay.
  qrt pcr delta ct: A-Z of Quantitative PCR Stephen A. Bustin, 2004 This book is a comprehensive manual to allow both the novice researcher and the expert to set up and carry out quantitative PCR assays from scratch. However, this book also sets out to explain as many features of qPCR as possible, provide alternative viewpoints, methods, and aims to simulate the researchers into generating, interpreting, and publishing data that are reproducible, reliable, and biologically meaningful
  qrt pcr delta ct: Rapid Cycle Real-Time PCR S. Meuer, C. Wittwer, K. Nakagawara, 2012-12-06 The first comprehensive treatise on Rapid Cycle Real-Time PCR. With amplification times of 15-30 minutes of on-line detection and analysis, nucleic acid quantification of mutation analysis finally becomes a routine, powerful and rapid method. Focusing primarily on the LightCycler, an instrument that combines Rapid Cycle PCR with fluorescent monitoring, this technology provides convenient analysis by melting temperatures. PCR products can be identified by product Tm, and single base mismatches can easily be genotyped by probe Tm. Methods chapters detail the theory behind quantification of mutation analysis; the design of synthesis of fluorescent hybridization probes of the preparation of template DNA. Application chapters apply nucleid acid quantification to infectious organisms of intracellular messengers and mutation detection to somatic of acquired mutations.
  qrt pcr delta ct: Real-time PCR M Dorak, 2007-01-24 With a variety of detection chemistries, an increasing number of platforms, multiple choices for analytical methods and the jargon emerging along with these developments, real-time PCR is facing the risk of becoming an intimidating method, especially for beginners. Real-time PCR provides the basics, explains how they are exploited to run a real-time PCR assay, how the assays are run and where these assays are informative in real life. It addresses the most practical aspects of the techniques with the emphasis on 'how to do it in the laboratory'. Keeping with the spirit of the Advanced Methods Series, most chapters provide an experimental protocol as an example of a specific assay.
  qrt pcr delta ct: Translational Medicine Dennis Cosmatos, Shein-Chung Chow, 2008-12-17 Examines Critical Decisions for Transitioning Lab Science to a Clinical SettingThe development of therapeutic pharmaceutical compounds is becoming more expensive, and the success rates for getting such treatments approved for marketing and to the patients is decreasing. As a result, translational medicine (TM) is becoming increasingly important in
  qrt pcr delta ct: Polymerase Chain Reaction for Biomedical Applications Ali Samadikuchaksaraei, 2016-12-14 Do you want to know the details that should be taken into consideration in order to have accurate conventional and real-time PCR results? If so, this book is for you. Polymerase Chain Reaction for Biomedical Applications is a collection of chapters for both novice and experienced scientists and technologists aiming to address obtaining an optimized real-time PCR result, simultaneous processing of a large number of samples and assays, performing PCR and RT-PCR on cell lysate without extraction of DNA or RNA, detecting false-positive PCR results, detecting organisms in viral and microbial diseases and hospital environment, following safety assessments of food products, and using PCR for introduction of mutations. This is a must-have book for any PCR laboratory.
  qrt pcr delta ct: Molecular Data Analysis Using R Csaba Ortutay, Zsuzsanna Ortutay, 2017-02-06 This book addresses the difficulties experienced by wet lab researchers with the statistical analysis of molecular biology related data. The authors explain how to use R and Bioconductor for the analysis of experimental data in the field of molecular biology. The content is based upon two university courses for bioinformatics and experimental biology students (Biological Data Analysis with R and High-throughput Data Analysis with R). The material is divided into chapters based upon the experimental methods used in the laboratories. Key features include: • Broad appeal--the authors target their material to researchers in several levels, ensuring that the basics are always covered. • First book to explain how to use R and Bioconductor for the analysis of several types of experimental data in the field of molecular biology. • Focuses on R and Bioconductor, which are widely used for data analysis. One great benefit of R and Bioconductor is that there is a vast user community and very active discussion in place, in addition to the practice of sharing codes. Further, R is the platform for implementing new analysis approaches, therefore novel methods are available early for R users.
  qrt pcr delta ct: Quantitative Real-Time PCR Roberto Biassoni, Alessandro Raso, 2014-04-17 Quantitative Real-Time PCR: Methods and Protocols focuses on different applications of qPCR ranging from microbiological detections (both viral and bacterial) to pathological applications. Several chapters deal with quality issues which regard the quality of starting material, the knowledge of the minimal information required to both perform an assay and to set the experimental plan, while the others focus on translational medicine applications that are ordered following an approximate logical order of their medical application. The last part of the book gives you an idea of an emerging digital PCR technique that is a unique qPCR approach for measuring nucleic acid, particularly suited for low level detection and to develop non-invasive diagnosis. Written for the Methods in Molecular Biology series, most chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, laboratory protocols and tips on troubleshooting and avoiding known pitfalls. Practical and authoritative, Quantitative Real-Time PCR: Methods and Protocols aims to aid researchers seeking to devise new qPCR-based approaches related to his or her area of investigation.
  qrt pcr delta ct: RT-PCR Protocols Nicola King, Joe O’Connell, 2008-02-04 Until the mid 1980s, the detection and quantification of a specific mRNA was a difficult task, usually only undertaken by a skilled molecular biologist. With the advent of PCR, it became possible to amplify specific mRNA, after first converting the mRNA to cDNA via reverse transcriptase. The arrival of this technique—termed reverse transcription-PCR (RT-PCR)—meant that mRNA suddenly became amenable to rapid and sensitive analysis, without the need for advanced training in molecular biology. This new accessibility of mRNA, which has been facilitated by the rapid accumulation of sequence data for human mRNAs, means that every biomedical researcher can now include measurement of specific mRNA expression as a routine component of his/her research plans. In view of the ubiquity of the use of standard RT-PCR, the main objective of RT-PCR Protocols is essentially to provide novel, useful applications of RT-PCR. These include some useful adaptations and applications that could be relevant to the wider research community who are already familiar with the basic RT-PCR protocol. For example, a variety of different adaptations are described that have been employed to obtain quantitative data from RT-PCR. Quantitative RT-PCR provides the ability to accurately measure changes/imb- ances in specific mRNA expression between normal and diseased tissues.
  qrt pcr delta ct: Principles of Molecular Oncology Miguel H. Bronchud, MaryAnn Foote, Giuseppe Giaccone, Olufunmilayo I. Olopade, Paul Workman, 2008-03-16 Drawing on years of significant advances and developments, the editors of this third edition have thoroughly updated the highly praised first and second editions and added new chapters to reflect the knowledge emerging from research on genomics, proteomics, chemoprevention strategies, pharmacogenomics, new molecular targets, therapeutic monoclonal antibodies, and innovative cytotoxic and cytostatic small molecular-weight molecules.
  qrt pcr delta ct: The Polymerase Chain Reaction Kary B. Mullis, Francois Ferre, Richard A. Gibbs, 2012-02-02 James D. Watson When, in late March of 1953, Francis Crick and I came to write the first Nature paper describing the double helical structure of the DNA molecule, Francis had wanted to include a lengthy discussion of the genetic implications of a molecule whose struc ture we had divined from a minimum of experimental data and on theoretical argu ments based on physical principles. But I felt that this might be tempting fate, given that we had not yet seen the detailed evidence from King's College. Nevertheless, we reached a compromise and decided to include a sentence that pointed to the biological significance of the molecule's key feature-the complementary pairing of the bases. It has not escaped our notice, Francis wrote, that the specific pairing that we have postulated immediately suggests a possible copying mechanism for the genetic material. By May, when we were writing the second Nature paper, I was more confident that the proposed structure was at the very least substantially correct, so that this second paper contains a discussion of molecular self-duplication using templates or molds. We pointed out that, as a consequence of base pairing, a DNA molecule has two chains that are complementary to each other. Each chain could then act . . . as a template for the formation on itself of a new companion chain, so that eventually we shall have two pairs of chains, where we only had one before and, moreover, ...
  qrt pcr delta ct: Cardiac Gene Expression Jun Zhang, Gregg Rokosh, 2008-02-03 This book presents both cutting-edge and established methods for studying cardiac gene expression. The protocols provide a template for solid research, and cover the process through screening, analysis, characterization, and functional confirmation of novel genes or known genes with a new function. The concluding section of the book highlights methods that facilitate overexpression or cardiac-specific targeted gene deletion.
  qrt pcr delta ct: Protocols in Advanced Genomics and Allied Techniques Aruna Pal, 2021-11-14 This laboratory manual includes the latest tools and techniques involved in genomic research. It starts with an introductory chapter on genomics and the various tools and applications involved. The initial chapters present protocols for basic techniques such as DNA isolation, electrophoresis, PCR, cDNA synthesis etc. The book then goes on to describe more advanced techniques such as next-generation sequencing, exome sequencing, use of RNAi, RNAseq, genome editing, single cell genomics etc. Each topic includes a brief description, information on the principles involved, materials & methods, protocol, and expected results, with diagrams and graphs. All protocols are presented in a very lucid and precise way, to make it easy for readers to follow and replicate them.
  qrt pcr delta ct: Protocols for Nucleic Acid Analysis by Nonradioactive Probes Elena Hilario, John F. MacKay, 2007-01-12 Protocols for Nucleic Acid Analysis by Non-radioactive Probes, Second Edition provides a firm background on the basic preparative protocols required for the analysis of nucleic acids by nonradioactive methods. Presenting the methodologies using amazing new applications, this volume offers guide chapters on nucleic acid extractions, preparation of nucleic acid blots, and labeling of nucleic acids with nonradioactive haptens. New fluorescent techniques such as Real Time PCR and microarrays are also included, allowing users to get a nonradioactive protocol implemented in the laboratory with minimum adaptation required and fastest time to results. The protocols follow the successful Methods in Molecular BiologyTM series format, each offering step-by-step laboratory instructions, an introduction outlining the principles behind the technique, lists of the necessary equipment and reagents, and tips on troubleshooting and avoiding known pitfalls.
  qrt pcr delta ct: Sugarcane Paul H. Moore, Frederik C. Botha, 2013-12-06 Physiology of Sugarcane looks at the development of a suite of well-established and developing biofuels derived from sugarcane and cane-based co-products, such as bagasse. Chapters provide broad-ranging coverage of sugarcane biology, biotechnological advances, and breakthroughs in production and processing techniques. This single volume resource brings together essential information to researchers and industry personnel interested in utilizing and developing new fuels and bioproducts derived from cane crops.
  qrt pcr delta ct: PCR Troubleshooting Michael L. Altshuler, 2006 This unique polymerase chain reaction (PCR) troubleshooting guide is an essential companion for readers with some experience in PCR. The book discusses the many and varied problems encountered with PCR, together with tips, advice, and procedures to obviate rather than overcome the PCR problems. The advice in PCR Troubleshooting is invaluable.
  qrt pcr delta ct: Heart Failure Longjian Liu, 2017-09-14 Get a quick, expert overview of the many key facets of heart failure research with this concise, practical resource by Dr. Longjian Liu. This easy-to-read reference focuses on the incidence, distribution, and possible control of this significant clinical and public health problem which is often associated with higher mortality and morbidity, as well as increased healthcare expenditures. This practical resource brings you up to date with what's new in the field and how it can benefit your patients. - Features a wealth of information on epidemiology and research methods related to heart failure. - Discusses pathophysiology and risk profile of heart failure, research and design, biostatistical basis of inference in heart failure study, advanced biostatistics and epidemiology applied in heart failure study, and precision medicine and areas of future research. - Consolidates today's available information and guidance in this timely area into one convenient resource.
  qrt pcr delta ct: Polymerase Chain Reaction Patricia Hernandez-Rodriguez, 2012-05-30 This book is intended to present current concepts in molecular biology with the emphasis on the application to animal, plant and human pathology, in various aspects such as etiology, diagnosis, prognosis, treatment and prevention of diseases as well as the use of these methodologies in understanding the pathophysiology of various diseases that affect living beings.
  qrt pcr delta ct: Modern Applied Biostatistical Methods Steve Selvin, 1998-02-19 Statistical analysis typically involves applying theoretically generated techniques to the description and interpretation of collected data. In this text, theory, application and interpretation are combined to present the entire biostatistical process for a series of elementary and intermediate analytic methods. The theoretical basis for each method is discussed with a minimum of mathematics and is applied to a research data example using a computer system called S-PLUS. This system produces concrete numerical results and increases one's understanding of the fundamental concepts and methodology of statistical analysis. Combining statistical logic, data and computer tools, the author explores such topics as random number generation, general linear models, estimation, analysis of tabular data, analysis of variance and survival analysis. The end result is a clear and complete explanation of the way statistical methods can help one gain an understanding of collected data. Modern Applied Biostatistical Methods is unlike other statistical texts, which usually deal either with theory or with applications. It integrates the two elements into a single presentation of theoretical background, data, interpretation, graphics, and implementation. This all-around approach will be particularly helpful to students in various biostatistics and advanced epidemiology courses, and will interest all researchers involved in biomedical data analysis. This text is not a computer manual, even though it makes extensive use of computer language to describe and illustrate applied statistical techniques. This makes the details of the statistical process readily accessible, providing insight into how and why a statistical method identifies the properties of sampled data. The first chapter gives a simple overview of the S-PLUS language. The subsequent chapters use this valuable statistical tool to present a variety of analytic approaches.
  qrt pcr delta ct: PCR Primer Design Chhandak Basu, 2016-10-08 This volume provides an overview on design PCR primers for successful DNA amplification. Chapters focus on primer design strategies for quantitative PCR, in silico PCR primer design, and primer design using software. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and easily accessible, PCR Primer Design, Second Edition seeks to aid molecular biology students, researchers, professors and PCR enthusiasts.
  qrt pcr delta ct: The Eurasian Huchen, Hucho hucho J. Holcík, K. Hensel, J. Nieslanik, L. Skácel, 2012-12-06 The need to gather available data on the Eurasien huchen - an important salmonid species - has been forced by a plain and, unfortunately, common fact of our times: the numbers and distribution of this biggest of salmonids have begun to decline and its range has begun to shrink. A seminar on the huchen - the European form of the species Hucha hucha - held in Zilina in February 1973 as a result of a suggestion of the Section for the Conservation of Fauna of the Slovak Zoological Society, indicated very clearly the sad situation. Data on the biology of the huchen are regrettably scarce despite several recent papers (Ivaska 1951, Svetina 1962, Prawochenski and Kolder 1968) with the aim of filling this gap. Supposing that without a thorough knowledge it is practically impossible to conserve any plant or animal species, the participants of the seminar concluded that the existing knowledge on the huchen should be compiled in an exhaustive monograph. The first such outline originated in 1977 under the authorship of J. Holcik, K. Hensel and L. Skacel, and was submitted as a research report to some of the central authorities. Even during the compilation of the report it became evident, however, that there is no difference between the huchen and its relative, the taimen. Consequently, we immediately began revising our first report, which took over three years.
  qrt pcr delta ct: Thermophilic Bacteria Jakob K. Kristjansson, 1991-11-22 Thermophilic Bacteria is a comprehensive volume that describes all major bacterial groups that can grow above 60-65°C (excluding the Archaea). Over 60 different species of aerobic and anaerobic thermophilic bacteria are covered. Isolation, growth methods, characterization and identification, ecology, metabolism, and enzymology of thermophilic bacteria are examined in detail, and an extensive compilation of recent biotechnological applications and the properties of many thermostable enzymes are also included. Major topics discussed in the book include a general review on thermophilic bacteria and archaea; heterotropic bacilli; the genus Thermus; new and rare genera of aerobic heterophophs, such as Saccharococcus, Rhodothermus, and Scotohermus; aerobic chemolithoautotrophic thermophilic bacteria; obligately anaerobic thermophilic bacteria; and hyperthermophilic Thermotogales and thermophilic phototrophs. Extensive bibliographies are also provided for each chapter. The vast amount of information packed into this one volume makes it essential for all microbiologists, biochemists, molecular biologists, and students interested in the expanding field of thermophilicity. Biotechnologists will find the book useful as a source of information on thermophiles or thermostable enzymes of possible industrial use.
  qrt pcr delta ct: Role of Medical Imaging in Cancers Stefano Fanti, Laura Evangelista, 2021-03-11 The issue of Cancers Journal entitled “Role of Medical Imaging in Cancers” presents a detailed summary of evidences about molecular imaging, including the role of computed tomography (CT), magnetic resonance imaging (MRI), single photon emission tomography (SPET) and positron emission tomography (PET) or PET/CT or PET/MR imaging in many type of tumors (i.e. sarcoma, prostate, breast and others), motivating the role of these imaging modalities in different setting of disease and showing the recent developments, in terms of radiopharmaceuticals, software and artificial intelligence in this field. The collection of articles is very useful for many specialists, because it has been conceived for a multidisciplinary point of view, in order to drive to a personalized medicine.
  qrt pcr delta ct: Wintrobe's Clinical Hematology John P. Greer, Daniel A. Arber, Bertil Glader, Alan F. List, Robert T. Means, Frixos Paraskevas, George M. Rodgers, 2013-08-29 With the 13th edition, Wintrobe’s Clinical Hematology once again bridges the gap between the clinical practice of hematology and the basic foundations of science. Broken down into eight parts, this book provides readers with a comprehensive overview of: Laboratory Hematology, The Normal Hematologic System, Transfusion Medicine, Disorders of Red Cells, Hemostasis and Coagulation; Benign Disorders of Leukocytes, The Spleen and/or Immunoglobulins; Hematologic Malignancies, and Transplantation. Within these sections, there is a heavy focus on the morphological exam of the peripheral blood smear, bone marrow, lymph nodes, and other tissues. With the knowledge about gene therapy and immunotherapy expanding, new, up-to-date information about the process and application of these therapies is included. Likewise, the editors have completely revised material on stem cell transplantation in regards to both malignant and benign disorders, graft versus host disease, and the importance of long-term follow-up of transplantation survivors.
  qrt pcr delta ct: Design and Analysis of DNA Microarray Investigations Richard M. Simon, Edward L. Korn, Lisa M. McShane, Michael D. Radmacher, George W. Wright, Yingdong Zhao, 2006-05-09 The analysis of gene expression profile data from DNA micorarray studies are discussed in this book. It provides a review of available methods and presents it in a manner that is intelligible to biologists. It offers an understanding of the design and analysis of experiments utilizing microarrays to benefit scientists. It includes an Appendix tutorial on the use of BRB-ArrayTools and step by step analyses of several major datasets using this software which is available from the National Cancer Institute.
  qrt pcr delta ct: Genetics and Breeding for Disease Resistance of Livestock Aruna Pal, A. K. Chakravarty, 2019-10-22 Genetics and Breeding for Disease Resistance of Livestock is a solid resource that combines important information on the underlying genetic causes and governing factors for disease resistance in food animals and applications for breeding purposes. It describes genomics at each species level to help researchers and students understand disease resistance and immunology using genomics and its application in breeding for disease resistance. This useful reference makes it easy for readers to understand and undergo further research in immunology and disease resistance for livestock. It includes novel applications and research material that is ideal for students, teachers, academicians and researchers. - Presents basic principles and protocols to describe research methodologies through diagrammatic illustrations with figures, flow charts, examples, and references - Covers various disease occurrences in livestock and the methodologies available to identify the various pathogens responsible for these diseases - Includes advanced breeding techniques and practical applications
  qrt pcr delta ct: Molecular Diagnostics Wayne W. Grody, Robert M. Nakamura, Frederick L. Kiechle, Charles Strom, 2009-11-06 Advances in genomic and proteomic profiling of disease have transformed the field of molecular diagnostics, thus leading the way for a major revolution in clinical practice. While the range of tests for disease detection and staging is rapidly expanding, many physicians lack the knowledge required to determine which tests to order and how to interpret results. Molecular Diagnostics provides a complete guide to the use and interpretation of molecular testing in the clinical arena. No other available resource offers this emphasis, comprehensive scope, and practical utility in the clinical setting. - Serves as the definitivereference for molecular pathologists worldwide - Covers a variety of molecular techniques including next generation sequencing, tumor somatic cell genotyping, infectious and genetic disease tecting, and pharmacogenetics - Discusses in the detail issues concerning quality assurance, regulation, ethics, and future directions for the science
  qrt pcr delta ct: Research on Nitrification and Related Processes, Part B , 2011-06-15 The global nitrogen cycle is the one most impacted by mankind. The past decade has changed our view on many aspects of the microbial biogeochemical cycles, including the global nitrogen cycle, which is mainly due to tremendous advances in methods, techniques and approaches. Many novel processes and the molecular inventory and organisms that facilitate them have been discovered only within the last 5 to 10 years, and the process is in progress. Research on Nitrification and Related Processes, Part B provides state-of-the-art updates on methods and protocols dealing with the detection, isolation and characterization of macromolecules and their hosting organisms that facilitate nitrification and related processes in the nitrogen cycle as well as the challenges of doing so in very diverse environments. - Provides state-of-the-art update on methods and protocols - Deals with the detection, isolation and characterization of macromolecules and their hosting organisms - Deals with the challenges of very diverse environments
  qrt pcr delta ct: Forensic DNA Analysis Jaiprakash G. Shewale, Ray H. Liu, 2013-08-19 The field of forensic DNA analysis has grown immensely in the past two decades and genotyping of biological samples is now routinely performed in human identification (HID) laboratories. Application areas include paternity testing, forensic casework, family lineage studies, identification of human remains, and DNA databasing. Forensic DNA Analysis: Current Practices and Emerging Technologies explores the fundamental principles and the application of technologies for each aspect of forensic DNA analysis. The book begins by discussing the value of DNA evidence and how to properly recognize, document, collect, and store it. The remaining chapters examine: The most widely adopted methods and the best practices for DNA isolation from forensic biological samples and human remains Studies carried out on the use of both messenger RNA and small (micro) RNA profiling Real-time polymerase chain reaction (PCR) methods for quantification and assessment of human DNA prior to genotyping Capillary electrophoresis (CE) as a tool for forensic DNA analysis Next-generation short tandem repeat (STR) genotyping kits for forensic applications, the biological nature of STR loci, and Y-chromosome STRs (Y-STRs) Mitochondrial DNA (mtDNA) sequence analysis Single nucleotide polymorphisms (SNPs) and insertion/deletion polymorphisms (indels) in typing highly degraded DNA Deep-sequencing technologies The current state of integrated systems in forensic DNA analysis The book concludes by discussing various aspects of sample-processing training and the entities that provide such training programs. This volume is an essential resource for students, researchers, teaching faculties, and other professionals interested in human identification/forensic DNA analysis.
  qrt pcr delta ct: Tick-Host-Pathogen Interactions Sarah Irène Bonnet, Ard Menzo Nijhof, Jose De La Fuente, 2018-08-24 Besides causing direct damage associated with blood feeding and in some cases through the excretion of toxins with their saliva, the main relevance of ticks lies in the wide variety of pathogens that they can transmit, including viruses, bacteria, protozoa and helminths. Owing to socioeconomic and environmental changes, tick distribution is changing with incursions of ticks and tick-borne diseases occurring in different regions of the world when the widespread deployment of chemical acaricides and repellents has led to the selection of resistance in multiple populations of ticks. New approaches that are environmentally sustainable and that provide broad protection against current and future tick-borne pathogen (TBP) are thus urgently needed. Such development, however, requires improved understanding of factors resulting in vector competence and tick-host-pathogen interactions. This Research Topic provides an overview of known molecular tick-host-pathogen interactions for a number of TBPs and highlights how this knowledge can contribute to novel control and prevention strategies for tick-borne diseases.
  qrt pcr delta ct: Signaling Pathways in Developing and Pathological Tissues and Organs of the Craniofacial Complex Thimios Mitsiadis, Claudio Cantù, Lucia Jimenez-Rojo, 2018-10-18 Head formation requires the well-orchestrated and harmonised development of various tissues and organs within the craniofacial complex. A big variety of signaling pathways are involved in this process by controlling cell proliferation, migration, differentiation, tissue morphogenesis, homeostasis and regeneration. Deregulation and malfunction of these signaling molecules may lead to mild or severe craniofacial pathologies. This eBook is a collection of articles dealing with a variety of important signals involved in the control of developmental and pathological events of craniofacial organs and tissues. These recent advances show the importance of signaling pathways in craniofacial physiology and pathology and generate important new knowledge aiming the development of new pharmaceutical products that mimic and/or block the actions of specific molecules.
  qrt pcr delta ct: Recent Advances in the Understanding of Hepatocellular Carcinogenesis, 2nd edition Prasanna K. Santhekadur, Bubu Ama Banini , Rohini Mehta, 2024-09-19 Hepatocellular carcinoma (HCC) is the most common cancer of the liver and the third most cause of cancer-related deaths worldwide. The 5-year survival of HCC is less than 20%, making HCC the second most lethal malignancy; the first being pancreatic cancer. HCC usually occurs in patients with chronic liver disease in association with a variety of risk factors, including chronic liver infection with hepatitis B virus or hepatitis C virus; excessive consumption of alcohol; overeating, obesity, and nonalcoholic fatty liver disease; other metabolic liver diseases including Wilson’s disease, hemochromatosis, and alpha-1-antitrypsin deficiency; and environmental toxins such as aflatoxins. Tobacco use and human immunodeficiency virus infection also increases the risk of HCC. The heterogeneity of HCC associated with different etiologies affects tumor initiation, development and progression, thus limiting the identification of consistent or routinely occurring genetic abnormalities characteristic of this malignancy. Nevertheless, sustained inflammation, hepatocyte regeneration, and apoptosis occurring in chronic liver disease results in fibrosis and ultimately cirrhosis, favoring genetic and epigenetic modifications that lead to the formation of dysplastic nodules and eventually oncogenesis. Identification of novel diagnostic and prognostic biomarkers for HCC is an unmet need in this current era. The aim of this Research Topic is to provide insights on novel aspects of HCC diagnosis, prognostication, and therapy with an emphasis on recent and up-to-date findings from the scientific literature. Genetic and molecular signatures arising from HCC in association with specific etiologies, and implications for cancer screening and surveillance will be discussed. As indicated sub-topics listed below, Original articles, Reviews and Mini-Review articles will address all areas of HCC relevant not only to basic and clinical researchers but also to practitioners in various fields of medicine: 1) Epidemiology of Hepatocellular carcinoma 2) Risk factors for hepatocellular carcinoma 3) Nonalcoholic Fatty Liver Disease and Hepatocellular Carcinoma 4) Animal models for studying hepatocellular carcinoma 5) Hepatocellular Carcinoma Oncogenes 6) Tumor suppressors and Novel regulators of Hepatocellular Carcinoma 7) MicroRNA and Hepatocellular Carcinoma 8) Circulating biomarkers of Hepatocellular Carcinoma
  qrt pcr delta ct: Prion Biology Vincent Béringue, 2013-04-08 This book contains a selection of chapters aimed to provide a better understanding prion structure and biology. Together these chapters provide an overview of prion biology and underscore some of the challenges we face if we want to understand how this lively pathogen propagates and evolves in mammals. There is also mounting evidence that studying prion biology has a wider relevance due to similarities in the processes of protein misfolding and aggregation between prion disorders and other neurodegenerative disorders such as Alzheimer’s, Parkinson’s, and Huntington’s diseases.
  qrt pcr delta ct: Plant Transformation Horacio Esteban Hopp, Luis Herrera-Estrella, German Spangenberg, 2022-05-10
  qrt pcr delta ct: Tumors of the Central Nervous System, Volume 1 M. A. Hayat, 2011-03-23 The most recent developments in diagnostic and therapeutic aspects of Gliomas (Glioblastoma) in the brain are presented. The importance of personalized medicine and clinical validation for targeted therapy are discussed. The identification of various types of biomarkers is included. The identification and validation of brain cancer (glioblastoma) genes are discussed. Role of cancer stem cells in the initiation, progression, and persistence of malignant gliomas is explained. The use of surgical resection, chemotherapy (e.g., temozolomide), immunotherapy, and radiotherapy for malignant glioblastoma are pointed out. Standard (established) as well as newer imaging modalities (proton magnetic resonance spectroscopy) are discussed.
  qrt pcr delta ct: Essentials of Stem Cell Biology Robert Lanza, John Gearhart, Brigid Hogan, Douglas Melton, Roger Pedersen, E. Donnall Thomas, James A. Thomson, Ian Wilmut, 2009-06-05 First developed as an accessible abridgement of the successful Handbook of Stem Cells, Essentials of Stem Cell Biology serves the needs of the evolving population of scientists, researchers, practitioners and students that are embracing the latest advances in stem cells. Representing the combined effort of seven editors and more than 200 scholars and scientists whose pioneering work has defined our understanding of stem cells, this book combines the prerequisites for a general understanding of adult and embryonic stem cells with a presentation by the world's experts of the latest research information about specific organ systems. From basic biology/mechanisms, early development, ectoderm, mesoderm, endoderm, methods to application of stem cells to specific human diseases, regulation and ethics, and patient perspectives, no topic in the field of stem cells is left uncovered. - Selected for inclusion in Doody's Core Titles 2013, an essential collection development tool for health sciences libraries - Contributions by Nobel Laureates and leading international investigators - Includes two entirely new chapters devoted exclusively to induced pluripotent stem (iPS) cells written by the scientists who made the breakthrough - Edited by a world-renowned author and researcher to present a complete story of stem cells in research, in application, and as the subject of political debate - Presented in full color with glossary, highlighted terms, and bibliographic entries replacing references
  qrt pcr delta ct: Neuroprotection Swapan K. Ray,
  qrt pcr delta ct: Cellular Neurophysiology Editors’ Pick 2021 Enrico Cherubini, Arianna Maffei, 2021-07-01
  qrt pcr delta ct: Hepatitis Delta Virus John L. Casey, 2010-02-12 Hepatitis delta virus (HDV), which causes severe acute and chronic liver disease, was discovered nearly 30 years ago following the detection of a novel antigen-antibody system in hepatitis B virus carriers. HDV has continued to surprise and fascinate medical science ever since. This volume reviews recent developments in HDV research, from molecular virology to genetics to experimental investigation of new therapeutic and vaccine candidates.