Spread of HTLV-I between lymphocytes by virus-induced polarization of the cytoskeleton

Cell contact is required for efficient transmission of human T cell leukemia virus- type 1 (HTLV-I) between cells and between individuals, because naturally infected lymphocytes produce virtually no cell-free infectious HTLV-I particles. However, the mechanism of cell-to-cell spread of HTLV-I is not understood. We show here that cell contact rapidly induces polarization of the cytoskeleton of the infected cell to the cell-cell junction. HTLV-I core (Gag protein) complexes and the HTLV-I genome accumulate at the cell-cell junction and are then transferred to the uninfected cell. Other lymphotropic viruses, such as HIV-1, may similarly subvert normal T cell physiology to allow efficient propagation between cells.     

Antiinflammatory effect of Japanese horse chestnut (Aesculus turbinata) seeds

The antiinflammatory effects of Japanese horse chestnut (Aesculus turbinata) seeds were examined in vivo and in vitro. The extract of this seed (HCSE) inhibited croton oil-induced swelling of the mouse concha. HCSE inhibited cyclooxygenase (COX) -1 and -2 activities, but had no effect on 15-lipoxygenase and phospholipase A2 activities. Inhibition of COX-2 occurred at a lower concentration of HCSE than for COX-1. Japanese horse chestnut seeds contain coumarins and saponins, but these chemicals did not inhibit COX activities. These results suggest that the antiinflammatory effect of Japanese horse chestnut seeds is caused, at least partly, by the inhibition of COX. The inhibitor of COX in this seed may be a chemical(s) other than coumarins and saponins.     

Receptor assay-guided isolation of anti-GABAergic insecticidal alkaloids from a fungal culture

The gamma-aminobutyric acid (GABA) receptor bears sites of action for insecticides. To discover GABA receptor-directed insecticides in natural products, fungal culture extracts were screened for their ability to inhibit specific binding of the radiolabeled noncompetitive antagonist [3H]1-(4-ethynylphenyl)-4-n-propyl-2,6,7-trioxabicyclo[2.2.2]octane to housefly head membranes. The screening efforts led to the isolation of two alkaloids from Aspergillus terreus: PF1198A (alantrypinone) and PF1198B (serantrypinone), which had IC50 values of 0.34 and 2.1 microM, respectively, in this assay. These compounds were ca. 47-61-fold selective for housefly vs rat GABA receptors. Both compounds showed insecticidal activity against Myzus persicae in the range of 100-500 ppm. Binding assay-guided screening should provide significant opportunities for the identification of novel and selective insecticides.     

Induction of (<Emphasis Type="Italic">Z</Emphasis>)-8-heptadecene in marine green alga <Emphasis Type="Italic">Bryopsis maxima</Emphasis> by mechanical wounding

ABSTRACT:   After mechanical wounding of the marine green alga Bryopsis maxima in a phosphate buffer, one main organic component was released to the solution. The organic compound was characterized by a molecular ion at 238  m/z by gas chromatography–mass spectrometry (GC-MS) and was deduced as 8-heptadecene by the fragment pattern. To identify the stereochemistry of 8-heptadecene, synthetic ( Z / E )-8-heptadecene was coinjected to the solution of wounded B. maxima . Comparing retention times and mass spectra with the synthetic sample, the target hydrocarbon obtained from wounded B. maxima was coincident with ( Z )-8-heptadecene.     

Veterinary education in the world—changing attitudes

SUMMARY Veterinary educators all over the world are concerned about the explosion in knowledge and about the way veterinary science is taught at present. How can we produce veterinarians who will provide the sort of care that will be expected in the year 2000 and beyond? In the recent past many schools have increased the information presented in their courses without removing any material. Student stress has increased, and undergraduates do not retain what they are taught. The type of assessment that is currently used often requires regurgitation of ‘facts’ rather than the solution of problems. This paper considers some of the issues that are pertinent to the future of veterinary education and suggests ways in which the situation may be improved. There is a need for increased activity by the Australian Veterinary Association to convince government that present funding is inadequate and that increased funding is urgently needed if we are to produce veterinarians of the quality the country will need in the next century.     

Multifunctional Alloys Obtained via a Dislocation-Free Plastic Deformation Mechanism

We describe a group of alloys that exhibit "super" properties, such as ultralow elastic modulus, ultrahigh strength, super elasticity, and super plasticity, at room temperature and that show Elinvar and Invar behavior. These "super" properties are attributable to a dislocation-free plastic deformation mechanism. In cold-worked alloys, this mechanism forms elastic strain fields of hierarchical structure that range in size from the nanometer scale to several tens of micrometers. The resultant elastic strain energy leads to a number of enhanced material properties.     

Enantioselective 2-hydroperoxylation of long-chain fatty acids in marine algae

SUMMARY: When long-chain saturated and unsaturated fatty acids were incubated with crude enzyme of marine green alga Ulva pertusa , the corresponding ( R )-2-hydroperoxy acids were found to have high enantiomeric excess (> 99%). In a similar administration experiment, the ( R )-2-hydroperoxy acid was obtained from the incubation of palmitic acid with crude enzymes of a variety of marine algae. Thus, we found that not only green algae but also brown and red algae are capable of enantioselective 2-hydroperoxylation of palmitic acid.     

High night temperature stimulates photosynthesis, biomass production and growth during the vegetative stage of rice plants

The effects of night temperature on biomass accumulation and plant morphology were examined in rice ( Oryza sativa L.) during vegetative growth. Plants were grown under three different night temperatures (17, 22 and 27°C) for 63 days. The day temperature was maintained at 27°C in all treatments. The final biomass of the plants was greatest in the plants grown at the highest night temperature. Total leaf area and tiller number were also the greatest in this treatment. Growth analysis indicated that the relative growth rate in the 27°C night-temperature treatment was maximal between days 21–42 and this was caused by increases in leaf area ratio, leaf weight ratio and specific leaf area. Plant total nitrogen contents did not differ among treatments. However, nitrogen allocation to the leaf blades was highest and the accumulation of sucrose and starch in the leaf blades and sheaths was the lowest in the 27°C night-temperature treatment by day 42. Despite this, dark respiration was also highest, and both the gross and net rates of CO₂ uptake at the level of the whole plant at day 63 were the highest in the 27°C night-temperature treatment. Thus, high night temperature strongly stimulated the growth of leaf blades during the early stage of rice plant growth, leading to increased biomass during the vegetative stage of the rice plants. As the CO₂ uptake rate per total leaf area was higher, photosynthesis at the level of the whole plant was also stimulated by a high night temperature.     

Discrimination between Virulent and Attenuated Isolates of Tomato mosaic virus by Restriction Fragment Length Polymorphism

The three missense mutations on the gene for the 130-K protein of Tomato mosaic virus (ToMV) L₁₁A have been thought to be responsible for the attenuation of its virulence. The Eco47I RFLP detecting the missense mutation at 2349 successfully discriminated L₁₁A and its derivative attenuated isolates from ToMV virulent ones. RFLP analysis and mismatch amplification assay detecting the missense mutations at 1117 and 2754, respectively, could not discriminate some of the attenuated isolates from the virulent ones. These results indicated that, of the three missense mutations, only the one at 2349 was conserved in all the L₁₁A-derivative attenuated isolates. Received 16 March 2001/ Accepted in revised form 22 June 2001