Mark D. Fricker

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Transport networks are ubiquitous in both social and biological systems. Robust network performance involves a complex trade-off involving cost, transport efficiency, and fault tolerance. Biological networks have been honed by many cycles of evolutionary selection pressure and are likely to yield reasonable solutions to such combinatorial optimization(More)
We provide evidence that the tripeptide thiol glutathione (GSH) participates in the regulation of cell division in the apical meristem of Arabidopsis roots. Exogenous application of micromolar concentrations of GSH raised the number of meristematic cells undergoing mitosis, while depletion of GSH had the opposite effect. A role for endogenous GSH in the(More)
The cytoplasmic pH of growing pollen tubes of Lilium longiflorum Thunb. was measured using the pH-sensitive fluorescent dye 2',7'-bis-(carboxyethyl)-5(6')-carboxyfl uorescein and confocal fluorescence ratio imaging. The average cytoplasmic pH in the clear zone of the pollen tube tip was pH 7.11, and no consistent pH gradients were detected in the clear(More)
  • G Thiel, M R Blatt, M D Fricker, I R White, P Millner
  • Proceedings of the National Academy of Sciences…
  • 1993
Transduction of the auxin stimulus in plants is thought to entail binding of the hormone to a soluble auxin-binding protein (ABP) outside the cell and subsequent interaction between this auxin-protein complex and an integral membrane receptor ("docking") protein that couples the signal across the plasma membrane. To explore the structural requirements for(More)
Reduction-oxidation-sensitive green fluorescent protein (roGFP1 and roGFP2) were expressed in different sub-cellular compartments of Arabidopsis and tobacco leaves to empirically determine their performance as ratiometric redox sensors for confocal imaging in planta. A lower redox-dependent change in fluorescence in combination with reduced excitation(More)
In animals, the impact of ROS production by mitochondria on cell physiology, death, disease and ageing is well recognised. In photosynthetic organisms such as higher plants, however, the chloroplast and peroxisomes are the major sources of ROS during normal metabolism and the importance of mitochondria in oxidative stress and redox signalling is less well(More)
Plant-derived nitric oxide (NO) triggers defence, priming the onset of the hypersensitive response and restricting pathogen ingress during incompatibility. However, little is known about the role of pathogen-produced NO during pre-infection development and infection. We sought evidence for NO production by the rice blast fungus during early infection. NO(More)
Transport networks are vital components of multicellular organisms, distributing nutrients and removing waste products. Animal and plant transport systems are branching trees whose architecture is linked to universal scaling laws in these organisms. In contrast, many fungi form reticulated mycelia via the branching and fusion of thread-like hyphae that(More)
The nuclear envelope consists of a double-membraned extension of the rough endoplasmic reticulum. In this report we describe long, dynamic tubular channels, derived from the nuclear envelope, that extend deep into the nucleoplasm. These channels show cell-type specific morphologies ranging from single short stubs to multiple, complex, branched structures.(More)
In Arabidopsis thaliana, trichome cells are specialized unicellular structures with uncertain functions. Based on earlier observations that one of the genes involved in cysteine biosynthesis (Atcys-3A) is highly expressed in trichomes, we have extended our studies in trichome cells to determine their capacity for glutathione (GSH) biosynthesis. First, we(More)