Plant wound compounds from oviposition scars used in host discrimination by a stem-galling sawfly

The stem-galling sawfly Euura lasiolepisuses one or more plant wound compounds resulting from oviposition scars as cues in host discrimination (avoiding sites occupied by conspecifics). Four experiments were conducted to test hypotheses about how Euurapartitions resources. Experiment 1 demonstrated that Euuraavoids ovipositing on nodes with scars from previous ovipositions. Experiment 2 showed no evidence that the sawfly uses oviposition-deterring pheromones and indicated there is a time lag following oviposition before the oviposition scar becomes a deterrent. Experiment 3 showed that sawflies avoid artificially formed scars, demonstrating that a plant cue alone can lead to host discrimination. Experiment 4 showed that visual or tactile cues are not necessary for host discrimination and indicated that a plant wound compound functions as an oviposition deterrent. Both experimental results and field surveys showed that Euuraoviposition scars were more uniformly distributed than expected if sawflies were ignoring previous ovipositions.     

Field test of resource regulation by the bud-galling sawfly, Euura mucronata, on Salix cinerea

The attack by the bud-galling sawfly, Euura mucronata , on its willow host was simulated by removing every other living bud from previous year's shoots in a natural stand of Salix cinerea . The impact of simulated attack on the growth of the willow and the subsequent attack by E. mucronata was estimated after one growing season. Experimental bud-killing resulted in a growth reaction in S. cinerea characterized by significant increase in the length of new shoots produced by the remaining buds Also the number of buds and E. mucronata galls per shoot were significantly higher on bud-removal branches as compared with control branches. The overall survival of E. mucronata larvae was better on long shoots than on short shoots. The result shows that sawfly attack increases the amount of high quality resources for the subsequent generation of the same sawfly as predicted by "resource regulation hypothesis". We conclude that these highly specialized insect herbivores have adapted to utilize and to maintain the willow's juvenile traits. Rapid regrowth of willows after damage may have originally arisen as an adaptation in response to other, less specific pressures such as mammal browsing or snow and ice damage.     

A prospective study of maternal and fetal outcome in acute Lassa fever infection during pregnancy.

Several viral infections have been reported to result in more severe disease in pregnant than non-pregnant women, but the relative risks have not been well characterised. This has now been done for Lassa fever in a prospective study of 68 pregnant and 79 non-pregnant women who were admitted to hospital in Sierra Leone with confirmed Lassa fever. Lassa fever was the main cause of maternal mortality in the hospital, accounting for 25% of maternal deaths. Twelve of 40 patients in the third trimester died, compared with two of 28 in the first two trimesters and 10 of 79 non-pregnant women. The odds ratio for death in the third trimester compared with the first two trimesters was 5.57 (95% confidence intervals 1.02 to 30.26). The condition of the mother improved rapidly after evacuation of the uterus, whether by spontaneous abortion, evacuation of retained products of conception, or normal delivery; 10 of 26 women without uterine evacuation died, but only four of 39 women with evacuation died (p = 0.0016). The odds ratio for death with pregnancy intact was 5.47 (95% confidence interval 1.35 to 22.16). Fetal and neonatal loss was 87%. The risk of death from Lassa fever in the third trimester is significantly higher than that in the first two trimesters and higher than that for non-pregnant women, but evacuation of the uterus can significantly improve the mother''s chance of survival.     

Cellular localization of a metabotropic glutamate receptor in rat brain.

In rat brain, the cellular localization of a phosphoinositide-linked metabotropic glutamate receptor (mGluR1 alpha) was demonstrated using antibodies that recognize the C-terminus of the receptor. mGluR1 alpha, a 142 kd protein, is enriched within the olfactory bulb, stratum oriens of CA1 and polymorph layer of dentate gyrus in hippocampus, globus pallidus, thalamus, substantia nigra, superior colliculus, and cerebellum. Lower levels of mGluR1 alpha are present within neocortex, striatum, amygdala, hypothalamus, and medulla. Dendrites, spines, and neuronal cell bodies contain mGluR1 alpha. mGluR1 alpha is not detectable in presynaptic terminals. mGluR1 alpha and ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits show differential distributions, but in Purkinje cells, mGluR1 alpha and specific AMPA receptor subunits colocalize. The postsynaptic distribution of mGluR1 alpha is consistent with postulated physiological roles of this subtype of glutamate receptor.     

Some factors that influence the plasma lipoprotein 1H NMR spectra of normal and cancer patients: an oncolipid test?

Selected factors have been evaluated in order to determine their influences on the plasma lipoprotein proton NMR spectra of normal and cancer patients. The variables were donor''s diet (fasting/non-fasting), temperature and time of sample storage, processing procedure, centrifugation speed, and water pre-saturation time. Plasma samples from fasting individuals that were placed immediately on ice, spun at 1,000 and 3,000 g for 15 minutes, and the proton NMR spectrum acquired with the Carr-Purcell Meiboom-Gill (CPMG) pulse sequence, using a two-second water pre-saturation time, consistently gave reproducible results. Resonances attributed to lactate were minimized under these processing conditions. Centrifugation speed and pre-saturation time did not affect the average line width; however, donor fasting state, processing temperature, and storage time did alter the line width. Most important, blood chemistry analysis revealed an inverse correlation between triglyceride levels and average methyl and methylene line widths. Thus, these factors alone caution against the indiscriminate use of proton NMR spectra to differentiate plasma from normal and cancer patients.     

The role of CDC28 and cyclins during mitosis in the budding yeast S. cerevisiae.

cdc28-1N is a conditional allele that has normal G1 (Start) function but confers a mitotic defect. We have isolated seven genes that in high dosage suppress the growth defect of cdc28-1N cells but not of Start-defective cdc28-4 cells. Three of these (CLB1, CLB2, and CLB4) encode proteins strongly homologous to G2-specific B-type cyclins. Another gene, CLB3, was cloned using PCR, CLB1 and CLB2 encode a pair of closely related proteins; CLB3 and CLB4 encode a second pair. Neither CLB1 nor CLB2 is essential; however, disruption of both is lethal and causes a mitotic defect. Furthermore, the double mutant cdc28-1N clb2::LEU2 is nonviable, whereas cdc28-4 clb2::LEU2 is viable, suggesting that the cdc28-1N protein may be defective in its interaction with B-type cyclins. Our results are consistent with CDC28 function being required in both G1 and mitosis. Its mitotic role, we believe, involves interaction with a family of at least four G2-specific cyclins.     

Reactivity of an anti-(human gastric carcinoma) monoclonal antibody with core-related peptides of gastrointestinal mucin

Summary A murine anti-(human gastric carcinoma) monoclonal antibody, GL-013 (IgG1), which reacts with a high-molecular-mass glycoprotein from colorectal tumour tissue [Yang and Price (1989) Anticancer Res 9: 1707], was examined for reactivity against a panel of purified and partially purified antigens associated with tumours of the gastrointestinal tract. These included carcinoembryonic antigen (CEA), normal cross-reacting antigen, Y-hapten glycoproteins, and perchloric acid extracts and glycolipid preparations from colorectal tumours. While the GL-013 antibody failed to bind to these antigens, it was found to react strongly with synthetic peptides with sequences based upon that reported for the protein core of a human gastrointestinal mucin [Barnd et al. (1989) Proc Natl Acad Sci USA 86: 7159; Gum et al. (1989) J Biol Chem 264: 6480]. In control tests, a series of other anti-(colorectal tumour) antibodies (IgG1 and IgG3), with broad reactivity towards gastrointestinal carcinomas, as well as an anti-CEA antibody, (IgG1) failed to react with the synthetic peptides. It is concluded that the anti-(gastric carcinoma) monoclonal antibody GL-013 binds to a threonine-rich peptide epitope expressed within the protein core of gastrointestinal mucins. Present address: Cancer Research Institute, China Medical University, Shenyang, Liaoning, People's Republic of China     

Conformation of a heptadecapeptide comprising the segment encephalitogenic in rhesus monkey

The 17-residue peptide FKLGGRDSRSGSPMARR derived from myelin basic protein, containing an epitope encephalitogenic in rhesus monkey, has been studied in aqueous solution by high-resolution one- and two-dimensional carbon and proton nuclear magnetic resonance spectroscopy. The resonances of the spectra from both nuclei were assigned with the aid of two-dimensional correlated spectroscopy, pH and solvent titrations, and one-dimensional spin-decoupling techniques and by comparison of the spectra of the heptadecapeptide with those of a phosphorylated form of the peptide, the pentadecapeptide FKLGGRDSRSGSPMA, and the nonapeptide FKLGGRDSR. Amide proton temperature coefficients, coupling constants, 13C- spin-lattice relaxation times, and nuclear Overhauser effect data suggest the existence of three structured regions comprising residues 3-6, 7-12, and 12-14 in the solution conformations of the encephalitogenic heptadecapeptide.     

Uptake of native and deglycosylated ricin A-chain immunotoxins by mouse liver parenchymal and non-parenchymal cells in vitro and in vivo

The therapeutic activity of ricin A-chain immunotoxins is undermined by their rapid clearance from the bloodstream of animals by the liver. This uptake has generally been attributed to recognition of the mannose-terminating oligosaccharides present on ricin A-chain by receptors present on the non-parenchymal (Kupffer and sinusoidal) cells of the liver. However, we demonstrate here that, in the mouse, the liver uptake of a ricin A-chain immunotoxin occurs in both parenchymal and non-parenchymal cells in equal amounts. This is in contrast to the situation in the rat, where uptake of the immunotoxin is predominantly by the non-parenchymal cells. Recognition of sugar residues on the A-chain portion of the immunotoxin plays an important role in the liver uptake by both cell types in both species. However it is not the only mechanism since, firstly, an immunotoxin containing ricin A-chain which had been effectively deglycosylated with metaperiodate and cyanoborohydride was still trapped to a significant extent by hepatic non-parenchymal cells after it was injected into mice. Secondly, deglycosylation, while eliminating uptake of the free A-chain by parenchymal and non-parenchymal cells in vitro, only reduced the uptake of an immunotoxin by either cell type by about half. Thirdly, the addition of excess D-mannose or L-fucose inhibited the uptake of free A-chain by mouse liver cell cultures by more than 80% but only inhibited the uptake of the native A-chain immunotoxin by about half and had little effect on the uptake of the deglycosylated ricin A-chain immunotoxin. Recognition of the antibody portion of the immunotoxin by liver cells seems improbable, since antibody alone or an antibody-bovine serum albumin conjugate were not taken up in appreciable amounts by the cultures. Possibly attachment of the A-chain to the antibody exposes sites on the A-chain that are recognised by liver cells in vitro and in vivo.