Prof Peter Hepler, from the University of Massachusetts, Amherst, USA, is visiting Robyn Overall's laboratory for the whole month of August. During his visit, Peter is conducting electron microscopy experiments alongside Debbie Barton to reveal how highly dynamic actin filaments are arranged at the rapidly growing tips of pollen tubes.

In August this year, Peter was awarded the Charles Reid Barnes Life Membership Award by the American Society of Plant Biologists in recognition of his distinguished career in plant cell biology. Since his PhD at the University of Wisconsin, Peter has been behind a long and varied list of discoveries about the plant cytoskeleton. These include discovering cross-bridging between microtubules in the mitotic spindle (which led to a new model of chromosome movement) and the mechanism behind cytoplasmic streaming through actin and myosin working like muscle fibers (giving further insight into subcellular action).

30 years ago, Peter began to investigate the small concentrations of Ca2+ acting as a second messenger but found large supplies in the ER when the cell plate was forming with pectin and Ca2+ after cell division. To investigate this further, he turned to germinating pollen because growth was localized at the tip, and vesicles containing wall precursors were focused there. He soon found that growth occurred in pulses out of phase with the precursor steps, leading to a method to separate the steps in vivo. He and his colleagues recently traced the pulsing action to a release of pectin by exocytosis. He proposed that the periodic release accelerates then decelerates the growth rate of the pollen tube to account for the pulsing action.

During his stay in Sydney, Peter is excited to use the university's microscopy facilities and share ideas with fellow pollen enthusiasts.

Matt commenced as a Postdoctoral Research Fellow in the Shine Lab in July after winning an Australian Research Council Linkage Grant. With the five years' funding, Matt will be investigating the biology and impact of cane toads in the southern part of their Australian range. After the discovery this year of a breeding toad population in Sydney, Matt will also be taking advantage of this new and isolated population to field-test emerging new methods for toad control.