R. A. Andersen

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The cytoskeleton of flagellate chromophyte algae, zoospores and gametes is active during swimming, phototaxis, several types of phagotrophic feeding, the formation, secretion and deployment of silica-scales, and the abrupt movement of spine-scales. The flagellar basal bodies are anchored by microtubular roots and/or fibrous roots. The kinds, numbers, and(More)
A bioassay system was developed to test the effects of volatile compounds on the growth of hyphae from germinating fungal spores. Volatiles from crushed tomato leaves inhibited hyphal growth of two fungal pathogens,Alternaria alternata andBotrytis cinerea. Aldehydes, including C6 and C9 compounds formed by the lipoxygenase enzyme pathway upon wounding(More)
Gain modulation, in which the sensitivity of a neural response to one input is modified by a second input, is studied at single-neuron and network levels. At the single neuron level, gain modulation can arise if the two inputs are subject to a direct multiplicative interaction. Alternatively, these inputs can be summed in a linear manner by the neuron and(More)
Very large concentration increases in nitrite (34-fold), nitrosated pyridine alkaloids, and related 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (14- to 33-fold) occurred in moist snuff during storage at 24 degrees C for 52 weeks, whereas, decreases in all parent and some acylated pyridine alkaloids were observed in the same material. Nitrite(More)
The terminology used to describe the cytoskeleton of protists is sometimes redundant and confusing. The independent origins of protistology from studies on algae, fungi, and protozoans led to these problems. Additionally, recent studies indicate that seemingly unrelated taxa form new, monophyletic groups. However, homologous structures that support(More)
C6-aldehydes are synthesized via lipoxygenase/hydroperoxide lyase action on polyunsaturated fatty acid (PUFA) substrates in plant leaves. The source pools and subcellular location of the processes are unknown. A close relationship is found between the composition of PUFA and the composition of C6-aldehydes. In the current study, this relationship was tested(More)
A reaction-time task was used to determine the visual motion thresholds in humans and in macaque monkeys for sinusoidally modulated shearing motion of a random dot display. It was found that humans and macaques were very similar in their spatial frequency sensitivity profiles for shearing motion. These profiles were of a U-shape for all human and monkey(More)
Low energies of near-ultraviolet radiation (300-400 nanometers), applied simultaneously with visible radiation to Nicotiana tabacum L. during daily illumination periods, increased levels of chlorogenic acid isomers, total soluble phenolics, alkaloids, and soluble sugars in expanding leaf lamina compared with controls that had near-ultraviolet filtered out.(More)
Flagellated vegetative cells of the colonial golden algaSynura uvella Ehr, were examined using serial sections. The two flagella are nearly parallel as they emerge from a flagellar pit near the apex of the cell. The photoreceptor is restricted to swellings on the flagella in the region where they pass through the apical pore in the scale case and the(More)
Damage to plant leaves by wounding or freezing induces the production of large amounts of C(6)-compounds. However, the control of formation of these compounds in leaves is not yet clear. In the current study, C(6)-aldehyde formation by freeze-injured soybean leaves of different ages (based on the leaf positions on the plant) at stage R1 of plant development(More)