Fluorescent activated cell sorter (FACS)

Sometimes during the persuance of research in life sciences, we reach at a point where we need to detect and/or separate a particular type of cell when many types of cells are present in the sample for reasons beyond human control. For example, if we are transforming a bacterial cell with a plasmid/expression vector which is tagged with fluorescent protein such as green fluorescent protein or yellow fluorescent protein  of cells in our sample. We need to separate the transformed cells from the untransformed cells. Here this difficult work can be easily carried out by FACS equipment.  FACS has built in lasers that detect the fluorescence emitted by fluorescent molecules, thereby distinguishes between various types of cells and can separate them as well on this basis. The basic principle of FACS is to tag the desired cell with a fluorescent antibody or to express a fluorescent protein in the cell. The original reason of invention of FACS was for separating cells but with the passage of time this equipment started getting used for other subfunctions as well. Due to this FACS nowadays comes in two versions.

1 Basic equipment (Cell counter, detector)
2 Basic equipment with cell sorter

FACS can be used for the detection, quantification, characterization and/or sorting cells.

Proliferation Assays

Proliferation assays as the name suggests are used to the estimate the proliferation of  cells in the sample. Measuring cellular proliferation is important as in many pathological (diseased) and physiological (normal) conditions, proliferation varies depending on the situation. For instance, vascular smooth muscle cells, a type of cells found in the middle layer of blood vessels (arteries) proliferate as a part of disease of blood vessels (atherosclerosis). Proliferation assays measures metabolic rate of the cell more or less which is infact an index of the growing or dying or fixed situation of the cell. Metabolic rate is measured through activity of an enzyme converted in the form of a visible dye which is quantified by taking absorbance at a certain wavelength. These assays are very sensitive as they can detect very less change in cell. Some of the popular versions of proliferation assays are listed below.

MTT Assay
Alamar blue Assay

Reference manager

Writing research documents like research articles, review articles,case reports is painstaking and time consuming so is the arranging citations, references and bibliography. In the earlier times, people used to add references manually and it was a much time consuming task and required meticulousness. Nowadays, computer programs are available which takes care of your citations and references. All you have to do is to add the references you required to write research articles to the software before or while you write it. These softwares add citations as well as bibliography while you write articles with a single click of mouse. Moreover, some of them provide enough space on the cloud to save articles as pdf as well while most of them provide space only to keep references only. Some of the good reference managers are Zotero, Mendeley desktop and Endnote.

Scientific writing

Scientific writing is writing technical documents such as research articles, review articles, case reports, letters. Usually for people who have English as a a second language, it is difficult to write in good English. Further, there is a huge knowledge which we need to know before we even start to plan for a research article or review article. One of the many books that is easy to understand and follow as well as contains comprehensive information on how to write scientific documents such as research articles, review articles is named "Scientific writing Easy when you know how". I hope that you will find what you are looking for to write your document.

Real Time Polymerase Chain Reaction

Real time polymerase chain reaction is a very popular technique used to measure gene expression level relative to various constitutively expressed genes such as Glyceraldehyde-3 phosphate dehydrogenase (GAPDH), beta-actin. It is based on the binding of SYBR green dye to double stranded DNA (dsDNA) as the amplification of complementary DNA (cDNA) takes place in PCR. SYBR green dye binds to dsDNA and fluoresce in the visible range emitting green color, thus the name SYBR green.

It consists of various preparative steps
1 mRNA extraction
2 cDNA preparation
3 RT-PCR