Tuning microbial growth

Vic Arcus and Jo McKenzie discover new metabolic regulation in microbes

As part of her PhD with Vic Arcus, Jo McKenzie has discovered a new mechanism of metabolic regulation in microbes. (images: Veronika Meduna)

Researchers at the University of Waikato have found a new mechanism of metabolic regulation in microbes, which allows bacteria to survive dramatic changes in their environment. Many microbes, including pathogens, have to adapt to frequent changes in conditions. For example, once Mycobacterium tuberculosis (the pathogen that causes tuberculosis) enters the human body, it is attacked by the immune system. However, it manages to survive, often lying dormant for long periods, in the acidic and oxygen-poor conditions within a type of immune cell called a macrophage.

As part of her PhD project with Vic Arcus, Jo McKenzie used a non-pathogenic close relative of M. tuberculosis to study a group of proteins that are known from many microbial species. She found that they cleave messenger-RNA, a molecule that is part of the translation process that turns DNA into proteins. By degrading certain subsets of m-RNA and thus stopping certain proteins from being produced, this mechanism provides a fast down-regulation of particular metabolic pathways, allowing bacteria to tune their growth to suit the conditions.

The proteins are found in half of all bacteria and archaea, and the team proposes that this RNA regulation is widespread and may have enabled some previously harmless microbes to become pathogenic.

How do Plants Know When to Flower?

Joanna Putterill heads the Flowering Lab, in the Plant Molecular Science Research Group at Auckland University. She uses molecular genetics to study how flowering is regulated in plants, and is particularly interested in how external cues, such as increasing day length in spring, work to trigger flowering. Her work to date has focused on the well-studied 'model Brassica' Arabidopsis thaliana, also know as thale cress, the first plant to have its entire genome sequenced. She has just received a Marsden grant, titled Springing into Flower after Winter to look at the effect of low winter temperatures, or vernalisation, in triggering flowering in a new model plant, the legume Medicago truncatula. Flowering-related genes discovered in such work could become important genetic markers to enable plant breeders to create new strains of plants that could be encouraged or discouraged to flower at certain times.

Kiwistar Optics

Eleanor Howick and Kiwistar's giant optical lenses

Eleanor Howick at work on one of the lenses, and the final touches being applied to one of Kiwistar's giant optical lenses. (images: Kiwistar Optics)

Hermes was the winged messenger of the gods in classical mythology, and chemical messages from outer space are helping us to understand the origin of our galaxy. Decoding these messages is the aim of HERMES, a major new project for the Australian Astronomical Observatory. They're building a giant spectrograph to study the chemical properties of more than a million different stars, trying to identify the specific clouds of dust and gas in which our galaxy was born. Daniel Zucker, a scientist working on HEREMES, tells Justin Gregory how it all works.

And some New Zealand know-how from local company KiwiStar Optics is helping Daniel in his search. Based in Lower Hutt, KiwiStar are building the lenses, cameras and mountings for the new spectrograph. Optical Workshop Manager David Cochrane takes Justin Gregory on a tour and explains the process.

Medicinal Chemistry

Margaret BrimbleMany of our best known pharmaceuticals originally came from nature, just think of quinine, penicillin, aspirin, ephedrine, and taxol, to name but a few. The University of Auckland'sMargaret Brimble(left) and her research team, including Mike McLeod and Daniel Furkert, are trying to make new medicines by synthesising chemicals from nature. The original compounds come from sources such as shellfish toxins (for spirolides) or complex molecules produced by organisms that live in extreme environments (such as berkelic acid). These compounds are then improved and tweaked in the lab.

The Medicinal Chemistry team has also been involved in the development by biotechnology company Neuren Pharmaceuticals of a therapeutic drug for traumatic brain injury. The drug is a synthetic analogue of a compound already produced in the brain, and in partnership with the US Army, is in clinical trials around the world. (image: University of Auckland)