Join 1 Million Scientists Who Use Our Advanced Technical Training In The Lab

In my previous blog on  experimental optimization, we discussed the idea of identifying the best antibody concentration for staining the cells. We did this through a process called titration, which  focuses on finding the best signal-to-noise ratio at the lowest antibody concentration. In this blog we will deal with sample blocking As a reminder, there are two other major binding concerns with antibodies. The first is the specific binding of the Fc fragment of the antibody to the Fc Receptor expressed on some cells. This protein is critical for the process of destroying microbes or other cells that have been…

TIRF is not as common as other microscopy based techniques due to certain restrictions. We will discuss these restrictions, then analyze why it might be perfect for your experiment.  TIRF relies on an evanescent wave, created through a critical angle of coherent light (i.e. laser) that reaches a refractive index mismatch.  What does it mean in practice?  A high angle laser reflects off the interface of the coverslip and the sample. Although the depth that this wave penetrates is dependent on the wavelength of the light, in practice it is approximately 50-300nm from the coverslip. Therefore, the cell membrane is…

NGS methodologies have been used to produce high-throughput sequence data. These data with appropriate computational analyses facilitate variant identification and prove to be extremely valuable in pharmaceutical industries and clinical practice for developing drug molecules inhibiting disease progression. Thus, by providing a comprehensive profile of an individual’s variome — particularly that of clinical relevance consisting of pathogenic variants — NGS helps in determining new disease genes. The information thus obtained on genetic variations and the target disease genes can be used by the Pharma companies to develop drugs impeding these variants and their disease-causing effect. However simple this may allude…

Over the next series of blog posts, we will explore the different aspects of optimizing a polychromatic flow cytometry panel. These steps range from figuring out the best voltage to use, which controls are critical for data interpretation, what quality control tools can be integrated into the assay; how to block cells, and more. This blog will focus on determining the optimal antibody concentration.  As a reminder about the antibody structure, a schematic of an antibody is shown below.  Figure 1: Schematic of an antibody. Figure from Wikipedia. The antibody is composed of two heavy chains and two light chains that…

2020 was a difficult year for many, with their own research being interrupted- either by lab shutdowns or recruitment into the race against COVID-19. Despite the challenges, scientists have continued to be creative and have pushed the boundaries of what is possible. These are the techniques and technologies that every microscopist was envious of in 2020. Spatially Resolved Transcriptomics Nature Methods declared that spatially resolved transcriptomics was the 2020 method of the year. These are a  group of methods that combine gene expression with their physical location. Single-cell RNA sequencing (scRNAseq) was originally developed for cells that had been dissociated…

Single Nucleotide Variant (SNVs) have been considered as the main source of genetic variation, therefore precisely identifying these SNVs is a critical part of the Next Generation Sequencing (NGS) workflow. However, in this report from 2004, the authors identified another form of variants called the Structural Variants (SVs), which are genetic alterations of 50 or more base pairs, and result in duplications, deletions, insertions, inversions, and translocations in the genome. The changes in the DNA organization resulting from these SVs have been shown to be responsible for both phenotypic variation and a variety of pathological conditions. While the average variation,…

What an incredible year 2020 has been. It started off like any other year and bam SARS-CoV-2 (aka COVID 19) entered the equation, bringing chaos and havoc to the world. Things kept changing overnight as new rules and regulations popped up. Masking, quarantine, and flatten the curve became common words in the news. How we met, how we interacted changed almost overnight. Throughout all of this, as we look to 2021, there is hope and optimism. Multiple vaccines have been developed, building on years of research into the SARS-CoV virus, with some approved for human use, and others on the horizon.…

As biologists, we study the process of life, however, it’s intricacies cannot be captured by a snapshot in time. Generally, the easiest imaging experiments are those where the samples are stained, fixed, and imaged within a few days of procurement, but that too doesn’t capture the dynamic processes common in cells and organisms. Live cell imaging when combined with reporters serves as a powerful tool to provide solid imaging data. Cameleon —one of the first reporters— was developed in 1997 in Roger Tsien’s lab.  Cameleon is a green fluorescent protein (GFP) that undergoes a conformational change in the presence of…

After genome assembly (covered in my previous blog) comes the vital step of gene prediction and annotation. This step entails the prediction of all the genes present in the assembled genome and to provide efficient functional annotation to these genes from the data available in diverse public repositories; such as Protein Family (PFAM), SuperFamily, Conserved Domain Database (CDD), TIGRFAM, PROSITE, CATH, SCOP, and other protein domain databases. It is imperative to understand that prediction and annotation of non-protein-coding genes, Untranslated Regions (UTR), and tRNA are as vital as protein-coding genes to determine the overall genetic constitution of the assembled genome. …

The heart and soul of the flow cytometry experiment is the ‘panel.’ The unique combinations of antibodies, antigens, fluorochromes, and other reagents are central to identifying the cells of interest and extracting the data necessary to answer the question at hand. Designing the right panel for flow cytometry is essential for detecting different modalities. The more parameters that can be interrogated will yield more information about the target cells. Current instruments can measure as many as 40 different parameters simultaneously. This is exciting, as it allows for more complex questions to be studied. Panel design is also valuable for precious samples,…

As scientists, we need to perform image analysis after we’ve acquired images in the microscope, otherwise, we have just a pretty picture and not data. The vocabulary for image processing and analysis can be a little intimidating to those new to the field. Therefore, in this blog, I’m going to break down 7 terms that are key when post-processing of images. 1. RGB Image Images acquired during microscopy can be grouped into two main categories. Either monochrome (that can be multichannel) or “RGB.” RGB stands for red, green, blue – the primary colors of light. The cameras in our phones…

The main goal for researchers, clinicians, and students who perform Next Generation Sequencing (NGS) and produce sequenced data for diverse projects involving human samples is to find biomarkers or variants to make diagnoses; and deduce the genetic anomalies that could be responsible for the disease they are conducting research on. Most projects (academic or non-academic) constitute the prior ideology on deciphering the “unknown.” There are well-versed computational protocols and pipelines formulated by labs across the world in determining what the “unknown” variants are. The fact that we have the “reference” human genome available – thanks to the Human Genome Project – plays…