First record of lily thrips, Liothrips vaneeckei Priesner, in Australia (Thysanoptera: Phlaeothripidae)

The first Australian record of the lily thrips, Liothrips vaneeckei Priesner, is reported from a bulb farm in Warragul South, Victoria. It is an occasional pest of Lilium bulbs, both in the field and in storage, particularly in the USA and several European countries, and is also infrequently found in considerable numbers on the corms of orchids.     

Inositol 1,4,5-trisphosphate signaling regulates rhythmic contractile activity of myoepithelial sheath cells in Caenorhabditis elegans

Intercellular communication between germ cells and neighboring somatic cells is essential for reproduction. Caenorhabditis elegans oocytes are surrounded by and coupled via gap junctions to smooth muscle-like myoepithelial sheath cells. Rhythmic sheath cell contraction drives ovulation and is triggered by a factor secreted from oocytes undergoing meiotic maturation. We demonstrate for the first time that signaling through the epidermal growth factor-like ligand LIN-3 and the LET-23 tyrosine kinase receptor induces ovulatory contractions of sheath cells. Reduction-of-function mutations in the inositol 1,4,5-trisphosphate (IP(3)) receptor gene itr-1 and knockdown of itr-1 expression by RNA interference inhibit sheath contractile activity. itr-1 gain-of-function mutations increase the rate and force of basal contractions and induce tonic sheath contraction during ovulation. Sheath contractile activity is disrupted by RNAi of plc-3, one of six phospholipase C-encoding genes in the C. elegans genome. PLC-3 is a PLC-gamma homolog and is expressed in contractile sheath cells of the proximal gonad. Maintenance of sheath contractile activity requires plasma membrane Ca(2+) entry. We conclude that IP(3) generated by LET-23 mediated activation of PLC-gamma induces repetitive intracellular Ca(2+) release that drives rhythmic sheath cell contraction. Calcium entry may function to trigger Ca(2+) release via IP(3) receptors and/or refill intracellular Ca(2+) stores.     

Chickpea wilt: identification and toxicity of 8-O-methyl-fusarubin from Fusarium acutatum

Fusarium acutatum was isolated from wilting chickpea plants in Pakistan. Filtrates from cultures grown on a defined liquid medium caused permanent wilting of chickpea cuttings and killed cells, isolated enzymically from healthy plants, in a bioassay. Toxic activity was retained by a cyano solid phase extraction cartridge and the toxin was isolated by elution from the cartridge in acetonitrile and Si-gel thin layer chromatography of the eluate. Analytical HPLC of the compound on a cyano column with diode array detection gave a single peak with a homogeneous spectrum and lambda(max) at 224 and 281 nm. NMR and mass spectral studies showed that the toxin was 8-O-methyl-fusarubin. The pure compound caused permanent wilting of chickpea cuttings and the LD50 value in the cell bioassay was 327 ng/ml.     

Early stages of p53-induced apoptosis are reversible

Apoptosis is a type of physiological cell death that occurs during development, normal tissue homeostasis, or as a result of different cellular insults. The phenotype of an apoptotic cell is relatively consistent in most cases of apoptosis and involves at least changes in the cell membrane, proteolysis of cytoplasmic and nuclear proteins, and eventual destruction of nuclear DNA. Our laboratory is interested in the reversibility of apoptosis. We have initial evidence that DNA repair is activated early in p53-induced apoptosis and may be involved in its reversibility. The present work further strengthens our proposition that p53-induced apoptosis is reversible. We show that p53 activation induces phosphatidylserine (PS) externalization early in apoptosis, and that these early apoptotic cells with externalized PS can be rescued and proliferate if the apoptotic stimulus is removed. In addition, we show that unscheduled DNA synthesis occurs in early apoptotic cells, and that if DNA repair is inhibited by aphidicolin, apoptosis is accelerated. These results confirm that early p53-induced apoptotic cells can be rescued from the apoptotic program, and that DNA repair can modulate that cell death process.     

A primary culture system for functional analysis of C. elegans neurons and muscle cells

C. elegans has provided important insights into neuromuscular system function and development. However, the animal's small size limits access to individual neurons and muscle cells for physiological, biochemical, and molecular study. We describe here primary culture methods that allow C. elegans embryonic cells to differentiate into neurons and muscle cells in vitro. Morphological, electrophysiological, and GFP reporter studies demonstrate that the differentiation and functional properties of cultured cells are similar to those observed in vivo. Enriched populations of cells expressing specific GFP reporters can be generated by fluorescence-activated cell sorting. Addition of double-stranded RNA to the culture medium induces dramatic knockdown of targeted gene expression. Primary nematode cell culture provides a new foundation for a wide variety of experimental opportunities heretofore unavailable in the field.     

855. IRIS STOLONIFERA

Iris stolonifera Maxim., from central Asia is illustrated. Its history is examined and current cultivars are listed. Suggestions for its cultivation are given.     

Partial purification of dopamine D2 receptors using lectin affinity columns

Dopamine D₂ receptors , detected by [³H]spiperone Dopamine D₂ receptors , detected by [³H]spiperone binding, were solubilized from bovine caudate nucleus by cholate/sodium chloride and were found to bind to wheat germ agglutinin immobilized on agarose. Specific elution could be achieved with N-acetylglucosamine whereas other sugars tested were inactive in this regard . The eluted preparation was enriched in solubilized receptors about sevenfold. The pharmaco-logical properties of the preparation were essentially unchanged by the lectin affinity purification procedure. The D₂ dopamine receptor is therefore a glycoprotein. binding, were solubilized from bovine caudate nucJeus by cholate/sodium chloride and were found to bind to wheat germ agglutinin immobilized on agarose. Specific elution could be achieved with N-acetylglucosamine whereas other sugars tested were inactive in this regard . The eluted preparation was enriched in solubilized receptors about sevenfold. The pharmacological properties of the preparation were essentially unchanged by the lectin affinity purification procedure. The D₂ dopamine receptor is therefore a glycoprotein.