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This post was contributed by Kusumika (Kushi) Mukherjee.

The ultimate goal in the field of regenerative medicine is to replace lost or damaged cells. Here, I will discuss the two major processes by which an adult somatic cell is converted to a different cell type for regeneration and repair and situations where one process is favored over the other.

Members of the bacterial world produce an assortment toxins to claim territory or kill competing microorganisms, but did you know bacteria also produce substances toxic to themselves?

These toxic substances are part of toxin-antitoxin systems that are widely present in bacteria. They consist of a toxin which can affect a variety of cellular processes and an antitoxin that suppresses the toxin’s activity. The key to these systems is that the toxin is stable while the antitoxin is unstable, meaning that the cells must continually produce antitoxin to avoid cell death.

This post was contributed by Kusumika (Kushi) Mukherjee, editor of Trends in Pharmacological Sciences, a Cell Press reviews journal.

Stem cells are special types of cells that can develop or “differentiate” into more specialized cells with specific functions [1]. In many tissues, stem cells serve to replenish/replace damaged cells that no longer function adequately [1]. Stem cells’ ability to differentiate into multiple cell types makes them useful models for developmental processes and promising therapeutic tools. The two unique characteristics that define stem cells are:

This post was contributed by Laura Lee, a graduate student at Stanford University.

Arabidopsis is a fantastic model organism for many reasons, not the least of which is ease of transformation. There are many motivations to generate transgenic Arabidopsis, from studying transcriptional and translational dynamics of genes and proteins in living plants, to complementing mutant phenotypes. Arabidopsis is amenable to the floral drip or dip transformation method. The general steps for this method include:

• Cloning and transforming a plasmid into the bacterium Agrobacterium tumeficans - a plant pathogenic species that stably integrates transfer DNA (tDNA) into the genomes of the plants it attacks
• Growing the transformed agrobacterium culture
• Dipping your plant’s flowers in the agrobacterium culture to allow for tDNA insertions into the plant’s germline
• Selecting for seeds that have the tDNA insertions (usually via seed growth on antibiotic-containing media)

My lab's vector of choice is AAV, with nearly every experiment requiring AAV. Before joining my lab, I had never worked with AAV, so naturally I had to package some virus for my first experiment. It was a bit intimidating, but I had my lab’s protocols and some great co-workers to help me out. Even with these tools, I found myself writing AAV production tricks into the margins of my protocol. While these tips weren’t critical to the experiment, they definitely made my life easier!  In this post, I’ll share some AAV production, purification, and titration tips, while also summarizing the basic steps and analyses needed for packaging AAV.