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Search below to delve into the Bitesize Bio archive. Here, you’ll find over two decades of the best articles, live events, podcasts, and resources, created by real experts and passionate mentors, to help you improve as a bioscientist. Whether you’re looking to learn something new or dig deep into a topic, you’ll find trustworthy, human-crafted content that’s ready to inspire and guide you.
As a biologist you will no doubt have seen Enzyme Commission (EC) numbers. An EC number is group of four numbers separated by periods in papers discussing enzymes…something like this: EC 1.1.2.1. But do you know what these numbers mean? Or where they came from? Or why we use them? If not, I will aim…
So having read our article on how a cytometer works, surely the next question is ‘what’s the right flow cytometer for me?!’ Basic Components of Flow Cytometers We know that at their most basic level, cytometers are made up of 3 main components: So, what are the considerations when selecting a flow cytometer? What…
Next-generation sequencing (NGS) really has taken the world by storm! In NGS, millions of short ‘read’s are sequenced in a short space of time, leaving you with vast amounts of data to analyze! For all NGS platforms, the input sample (i.e. your cell free DNA) must be cleaved into short sections or fragments prior to…
“Any sufficiently advanced technology is indistinguishable from magic.” – Arthur C. Clarke In the fast-moving field of next generation sequencing, standard practices are evolving rapidly. Today, more and more labs are using Solid Phase Reversible Immobilization (SPRI) beads instead of gel purification in the preparation of libraries for sequencing. A crucial step, not for the…
Following on from our previous article, here are some suggestions for an old microscope (should you happen not to destroy it!). 1. Museum piece Start your own mini scientific instruments museum. Before you know it, you be raking through the old skips and dumpsters at your institute looking for exhibits. 2. Teach kids Teach your…
Apart from lung cells, surprisingly few cells are ever exposed to 20% oxygen, which is one of the reasons it’s hard to get in vitro cell cultures to behave. Read more about whether 20% oxygen is always the best level for cell culture and why it became the standard amount to use.
Do you see what I see? Maybe not, if the microscope is wrecked in one of these ten ways when you… 1. Carry the microscope incorrectly. A death-grip on anything but the arm and the base almost guarantees that it will slip away, crashing onto the floor to break in pieces. You don’t want a microscope which…
Did you ever encounter resistance from a mammalian cell line when trying to extract the contents? Probably not, because destroying cell membranes is easy. Cell walls, however, are a different story. They are rigid, protective layers that can be so strong that the organism gives up movement in favor of protection! Cell walls exist in…
For those of you who prepare your own DNA libraries, this article will cover the most critical aspects of library preparation to ensure a successful sequencing run. Previous Bite Size Bio articles have covered the basics of how 454 sequencing works, so give those a quick review if you are unfamiliar with the process. This video is also highly…
Do you know what your histology fixatives are really doing to your samples? Read on to learn what happens to tissue treated with two common fixatives.
What Does Oil Red O Stain? Oil Red O (‘ORO’) is used to demonstrate the presence of fat or lipids in fresh, frozen tissue sections. Introduced by French in 1926, ORO is a fat-soluble diazo dye, and is classified as one of the Sudan dyes which have been in use since the late 1800s. Like…
Want to detect iron in your samples? You need Prussian blue! Discover the incredible sensitivity of this stain and how to use it.
In my previous article on DNA gel extraction, I explained how most commercially available DNA gel extraction kits work. However, there was a time before our society was blessed with these convenient marvels of technology and scientists had to summon the gods of “Crush and Soak”. This method has been proven for millennia, as people…
Size Selection via Gel Electrophoresis Whether you are using NGS for whole genome sequencing, SNP variant analysis, HLA typing, HLA matching, or even transcriptome or miRNA analysis by RNA-seq, size selection is an extremely important consideration for optimum results. Precise size selection can increase sequencing efficiency, save money and improve genome assemblies, as well as…
Isolating pure DNA is key to many downstream applications for molecular biologists. Isolating large quantities of pure DNA used to be a laborious task. But thanks to commercially available kits, older methods have been streamlined to allow efficient recovery of pure DNA. In this article, I will talk about a method called DNA gel extraction, which…
The study of geometric probability in stereology may seem like a large, overwhelming area of focus but, don’t panic, it’s not! In fact, it is a very specific field that is likely to come easy to those that excel in mathematics or science (yes that means you). However, the concept is not one that most…
So you’ve isolated your DNA or RNA from your favorite sample. And now, if you are anything like me, the first thing you’ll do is scramble to check the quality and concentration of your extract. You have a few different options at your disposal to perform this crucial analysis, which will let you know whether…
You’ve carefully collected your samples, extracted nucleic acids and made your first set of next-generation sequencing libraries. How are you going to know if the data you get back is any good and whether it will be worth the effort in learning how to do the analysis? Who is to blame? Fortunately, there are several…
So you want to do meiotic spreads do you? Maybe it’s to check if meiosis is progressing the way it should, or even to look for sites of DNA damage. Whatever the case this technique can be a little tricky at first, but once you learn a few tricks it’s like riding a bicycle- so…
Ribonucleases (RNases). We’ve been giving them a hard time here lately. We’ve been talking about how they are the bane of the lives of researchers who work with RNA. And we’ve told you how to find their weaknesses and shown you a myriad of weapons that you can use to kick their RNase butts. But…
If you want a more efficient, cheaper way to do bacterial transformation, you are definitely going to like this article.
You might have heard about the new techniques that fall under the umbrella of ‘Super-Resolution Microscopy’. In this article, we’ll look at diffraction limits and how to overcome them using Super-Resolution Microscopy techniques. The Limits of Light Microscopy Light microscopy is one of the most versatile tools in a biologist’s arsenal, but from its invention…
Discover interesting facts about Congo red and it can help us understand Alzheimer’s disease.
Why do I see a cloud? When you are looking at protein localization within a cell, have you ever wondered why you see a cloud of fluorescence rather than several individual fluorescent points? Well, light microscopy has a theoretical resolution limit of 200 nm. Well, light microscopy has a theoretical resolution limit of 200 nm….
You have spent days, if not weeks, at the bench setting up the treatment and control samples for that crucial experiment. You submitted your cDNA library for sequencing and after a few weeks of waiting anxiously you get back a list of differentially expressed genes. Hooray?! Hold on- not quite yet! There is something you…
RNases are like the baddie super-heroes amongst laboratory enzymes. They are omnipotent, destructive and seemingly indestructible. This is because they were created by evil overlords, for the sole purpose making life difficult for the brave scientists who battle every day to produce high quality, intact RNA preps. Ok, I’m joking about the overlords part. But…
Acid-fast stain (AF) is a special staining technique used in the histology lab. Discover which bacteria this stain detects, the history behind it, and how it works.
There is no such thing as “junk” DNA Until recently, vast areas of the genome had been denounced as “junk” DNA, because they do not encode proteins. However, it has become clear that these regions have a large diversity of other functions, from transcriptional and translational regulation to the protection of genes and genome integrity….
Gomori’s methenamine silver is a special histology stain for detecting fungi. Find out how and why you might want to use this stain in the lab.
MicroRNAs (miRNA) are short, non-coding RNAs involved in post-transcriptional silencing of gene expression. miRNAs can be associated with exosomes and can function as cancer-specific biomarkers. This, coupled with the fact that they are stable in plasma and serum makes them valuable diagnostic tools, as long as they can be reliably isolated from the serum and…
In a recent article, I gave some tips about how to obtain good results with sequencing DNA after bisulfite conversion (it contains some tips that apply to the approach described in this article, too). Bisulfite sequencing is a very useful technique if you want to know the methylation status of every CpG in your genomic…
In my last article, I explained that plasmid DNA recovered from a plasmid prep consists of few different species; supercoiled, nicked, linear and single stranded circular, and how you can distinguish them on a gel. Supercoiled DNA is the desired form of plasmid DNA; it performs better in downstream applications such as automated sequencing and…
In my previous article, I covered different immunohistochemical staining techniques at a superficial level. In this post, I will start to explain these technologies in a bit more detail and in which situations they should be applied. All of the following will involve additional stages when applying them, for example, serum blocking, protein blocking, avidin-biotin…
For those of you who print out the results that you have acquired from the Flow Cytometer to stick in your lab book, did you know that inkjet printers and cytometers have a shared history? Flow Cytometry is less than 50 years old and machines today still use some of the same principles as the…
Reference genes are essential for accurate gene expression analysis, controlling for sample variation and experimental differences. Selecting stable reference genes depends on tissue type, and using multiple genes improves normalization. Literature reviews help identify reliable genes like HPRT1, ACTB, and B2M. Proper use of reference genes ensures consistent RT-PCR results even with limited starting material, supporting robust and reproducible bioscience research.
Alternative splicing is a highly orchestrated process that uses a multitude of regulatory mechanisms. Splicing specificity involves a precise interaction between cis- and trans-acting regulatory elements, and factors that disrupt these interactions can result in aberrant splicing. There are multiple ways in which mutations can affect splicing fidelity: Global analysis of alternative splicing is essential…
Conserved elements are stretches of DNA sequence that are under purifying selection. That means mutations leading to a change of function in this part of the DNA are detrimental to the organism and will not become fixed in the genome, but rather discarded by natural selection. The level of conservation between species gives an idea…
A commonly used technique in epigenetics is Chromatin Immunoprecipitation, or ChIP for short. This technique can show you whether a certain protein (e.g. transcription factor or histone modification) binds to DNA, when in its native conformation, namely chromatin. Insightful, but difficult This information can be very insightful, but difficult to obtain. Most protocols and suggestions…
The ELISA (enzyme-linked immunosorbent assay) is a rapid method used to detect the amount of a protein of interest in clinical and experimental samples. There are a number of ELISA formats to choose from, depending on your research needs. These include direct ELISA, indirect ELISA, competitive ELISA and sandwich ELISA. We have previously covered the…
According to the International Society for Stereology, the area of scientific study encompassed by this term is that which analyzes solids. If that all sounds a bit too much like materials science, then for us microscopists, it’s really about the review of three-dimensional objects (mainly tissues) by making horizontal and vertical incisions. Stereology can be…
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