RNA

Dietary delivery of small RNAs: Has the worm turned?

“You are what you eat,” as the saying goes, which serves for some as a guide to healthy eating. Even the field of nutrition appreciates the literal nature of this adage: as our bodies renew aging cells, our diets provide the necessary building blocks to repair and maintain them. We need basic nutrients, vitamins, and minerals for proper development and to maintain our health, but what about small RNA molecules? There is a growing interest in small RNAs because they regulate the expression of genes in living organisms, and are not only present in our food to begin with but are also being tested in genetically engineered crops to create useful traits. While experimental biologists have used dietary small RNAs to exert regulatory changes in worms for decades, few scientists would recognize small RNAs as nutrients. Several recent reports by Baier et al. and Zhou et al. (see references 1,

arctic apple vs regular crop

A Misplaced Concern about an Apple

As a consumer and as an agricultural scientist, I’m looking forward to the introduction of the Arctic® apple. It is possibly nearing approval by regulators in the US and Canada which could mean that supplies might finally be available in a few more years.  These apples could give consumers the possibility of buying apples that maintain their flavor, appearance and vitamin content after cutting, and which can also be used to make beautiful dried apple slices without the need for sulfites (something that can be a problem for some people).  This is an excellent example of how plant biotechnology can provide direct consumer benefits. The Arctic® apple “works” through a mechanism called “RNAi.” That is a way to “turn off” a gene – in this case the genes for the enzymes that cause apples to brown when cut.  RNAi is a common, natural means of genetic regulation in plants, animals,

applmrna

So Much for My Favorite 2012 Paper

Republished from Illumination. Ask any scientist what papers truly intrigued or inspired them.  All of us have a few. One of my favorites hit Cell Research back in summer of 2012.  In this paper, Zhang et al claimed that dietary microRNAs from rice were somehow ushered through the digestive gauntlet and modulated physiologically relevant changes in LDL, at least in mice.  MicroRNAs are a relatively recent regulatory regimen, a monkey wrench in the central dogma in of molecular biology.  These tiny runs of a 1-2 dozen nucleotides interact with RNA, leading to its degradation. They interact with RNA to change translation and bind to DNA to inspire transcriptional control.  In other words, they place a new layer of complexity into a complex process. We know that there are 1000+ microRNAs in the human genome and probably just as many in plants.  The work by Zhang was so cool because it said

Showing the secondary structure present in pre-miRNAs.

Why novel dsRNA molecules in GM food are of little to no concern

Recently, concerns were raised about the potential risks of dietary double stranded RNA (dsRNA) and microRNA (miRNA) molecules silencing human genes, after research by Zhang et al. showed the presence of plant miRNA in human blood plasma, as well as providing evidence that this plant miRNA enters the system by dietary uptake in mice. The group then demonstrated that this plant miRNA could silence genes in the mice, leading other researchers to separately raise concerns that diets consisting of genetically modified organisms could lead to the uptake of novel dsRNA molecules that could silence human genes. Gene-silencing by RNA interference, or RNAi, typically occurs by way of short sequences of RNA which bind to a target messenger RNA sequence (mRNA) and inhibit it, either signaling the mRNA for deletion or inhibiting its expression. This occurs through perfect or near-perfect base pairing of the sequence to a short segment on the mRNA strand.

Stoking fears to sway your emotions

GMO Wheat and shouting “fire” in a crowded theater

A report from an activist group called Safe Food Foundation (SFF) came out last fall that caused a minor stir upon it’s first release. They claimed that they had unearthed an issue with GMO wheat being studied by the Australian CSIRO researchers. The wheat under investigation has shown to provide improvements in digestive health in animal studies and could potentially lower the glycemic index of foods. SFF threw a press conference, did a YouTube video, and managed to get some press about it. Here’s a New Zealand newspaper that picked up the claims. But as the story unfolded, it quickly became apparent that their claims were wrong and irresponsible.