the community site for and by developmental biologists

About: Linda

Biography:
I hail from Canada, but migrated South to Australia for balmy weather and research. I do all kinds of unethical things to plants to unravel the mystery that is RNAi.
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Posts by Linda:

An After Thought to Evolution: Exceptional ways of Controlling Gene “Expression”

Posted by on May 3rd, 2011

More and more, the central dogma is becoming well, dogged, for being a dogma at all. As humans, we have 3 billion nucleotides. Only 1% of it makes up our protein coding genes, which led to the development of the central dogma: DNA is transcribed to RNA and translated into proteins. During undergrad, we’re taught[…]

Got the Blues? How Plants Respond to Blue Light

Posted by on April 28th, 2011

Physiologically speaking of course….

As humans we can see a limited assortment of light wavelengths, known as the visible spectrum of light, a.k.a. colours. (Other wavelengths we cannot see include UV rays, X rays or infrared). Why is it that we can differentiate colours? Its likely to do with adaptation to the environment. Plants and animals have evolved different physiological responses to colours, so it’s important to discriminate between them.

As mammals we have biological clocks, or circadian rhythms that respond to light. Dark or blue light set off signalling mechanisms, which ultimately regulate the melatonin levels in our system. Melatonin is a hormone which can induce sleep, if at sufficiently high levels in our system. (Hence your doctor prescribing you melatonin if you have trouble sleeping at night. Suffice to say countless grad students are probably on this stuff right now).

Plants also have a light-sensing system, which can respond to different times of day and seasonal changes. This can determine fruit maturation and changing colour in the leaves etc. For plants, blue light has a revitalizing (instead of drowsy) effect. If you’ve ever left your plants without light for too long, they go yellow. Irradiate them with a little blue, and the green will return within a couple of days.

Interestingly, plants and animals have the same type of photoreceptors to blue light, called Cryptochromes (CRYs), even though they elicit a different response. CRYs initiate the light response, analogous to a molecular domino effect. The pigments bind specialized proteins that in turn, regulate transcription factors that can switch on the light response genes involved in development. Termed as photomorphogenesis, light dependent changes in development can include initiation of flowering, or extension of roots in germinating seeds.

Currently, characterizing the molecular interactions in plant blue-light/CRY1 response seems to be a hot topic. Two highly similar articles were just published in Genes & Development, which was drawn to my attention by Eva (cheers). They were produced by two different research crews, using virtually the same methods to similar results. It’s not by total coincidence either. Characterizing molecular interactions in plants involve the same gold standard biochemical and genetic assays (i.e. transgenic plants, yeast hybrid systems, loss-of-function mutants etc.)

(Photoreceptors = light absorbing molecules or pigments.)

A Lab Murder Mystery

Posted by on February 18th, 2011

“A researcher is found dead hunched over her lab bench, and seven suspects are in custody. Now it’s up to 30 high school students to determine who killed her.” To quote from the UBC Science newsletter. Don’t be alarmed, this isn’t tabloid fodder. It’s actually part of a high school out-reach program, organized by UBC’s grad student[…]

If Animals Could Speak

Posted by on February 17th, 2011

I’ve no doubt that this is what they’d say: Or maybe this is what they really sound like and Sir David Attenborough refused to share this with us on the BBC. Just for fun! I bet UK residents are very familiar with BBC One’s Walk on the Wild Side. Now to enlighten the rest of the[…]

Natural Disasters and University Disruptions

Posted by on February 6th, 2011

Natural disasters can be powerfully destructive forces. At the very least, they have a habit of interrupting our lives and work. Damage varies depending on the intensity of nature’s fury and how prepared a city (or institution) is for a particular emergency. This can also influence how challenging recovery will be, in the aftermath. The[…]

Blogging the Flood at the University of Queensland

Posted by on January 30th, 2011

On January 12th, about three quarters of the Australian State of Queensland was flooded as local rivers and creeks overflowed from rainfall. Needless to say, it’s been an extremely wet summer. One victim was the University of Queensland, which still stands next to the Brisbane River, the cause of the city of Brisbane’s troubles. Flood[…]

RNAi in the Nucleus ~ It’s no longer limited to the cytoplasm

Posted by on January 18th, 2011

Hot off the press from the holidays is an article from PNAS that’s worth a gander if you’re into RNAi. We know RNAi associated with epigenetics is possible in the nucleus (Somehow, siRNAs could trigger the methylation and silencing of genes in the nucleus.) However, one soy bean group was able to provide evidence for[…]

Arrested Development in Plant miRNA Mutants

Posted by on January 11th, 2011

Animals and Plants have hundreds of miRNAs with diverse roles in gene regulation. In humans, each miRNA family can control up to several hundred genes (or 500 to be exact, in humans). A loss of function in one, can lead to array of developmental defects. Similarly in plants, an miRNA mutant can have a variety of phenotypes. However, interestingly, many miRNAs only have one target, which is frequently a transcription factor that in turn, controls many genes itself. It’s really like a house of cards.

The Rolling Stone Gathers No Moss

Posted by on January 5th, 2011

But you know he’ll always keep movin’ You know he’s never gonna stop movin’ Cause he’s rollin’, he’s a rollin’ stone ~ Baker Street, by Gerry Rafferty (Link to Song on Youtube) Something to ponder. whether you’re a rock star or researcher, you’re bound to be on the road at some point. Seldom do researchers[…]

Celebrating NYE with Bioluminescence

Posted by on December 31st, 2010

Let me take you on a Bioluminescent journey across many kingdoms. If you’re not well acquainted with the term, it’s the ability of living things to chemically produce light. It’s also a natural widespread feature to many organisms, from jellyfish to algae, fireflies to fungi. In recent years, it’s become a standard molecular biological tool for[…]