Field study of plant survival as affected by amendments to bentonite spoil

Efforts to reclaim amended and raw bentonite spoils with six plant species (two forbs, three shrubs, and one tree) were evaluated over a 4-year period. Plant species included fourwing saltbush ( Atriplex canescens [Pursh] Nutt.), big sagebrush ( Artemisia tridentata tridentata Nutt.), Rocky Mountain Juniper ( Juniperus scopulorum Sarg.), Russian olive ( Elaeagnus angustifolia L.) common yarrow ( Achillea millifolium L.) and scarlet globemallow ( Sphaeralcea coccinea [Pursh] Rydb.). Spoil treatments included addition of gypsum, sawdust, perlite, straw, and vermiculite; the control treatment was amended. Fourwing saltbush had 52% survival across all spoil treatments, with greatest survival occurring on perlite-treated spoil (80%), followed by gypsum (70%) and vermiculite amendments (70%). Survival of other plant species ranged from 0 to 2% averaged across all treatments after 4 years. No differences in plant survival occurred among amendments when all species were considered.     

Synthese von Vitamin-A-Methyläther

Summary Preliminary report on the synthesis of vitamin A methyl ether starting from 4-trimethylcyclohexenyl-2-methyl-butenal and 1-methoxy-3-methyl-pentenin.     

Substantial increase of protein stability by multiple disulphide bonds

Disulphide bonds can significantly stabilize the native structures of proteins. The effect is presumed to be due mainly to a decrease in the configurational chain entropy of the unfolded polypeptide. In phage T4 lysozyme, a disulphide-free enzyme, engineered disulphide mutants that crosslink residues 3-97, 9-164 and 21-142 are significantly more stable than the wild-type protein. To investigate the effect of multiple-disulphide bonds on protein stability, mutants were constructed in which two or three stabilizing disulphide bridges were combined in the same protein. Reversible thermal denaturation shows that the increase in melting temperature resulting from the individual disulphide bonds is approximately additive. The triple-disulphide variant unfolds at a temperature 23.4 degrees C higher than wild-type lysozyme. The results demonstrate that a combination of disulphide bonds, each of which contributes to stability, can achieve substantial overall improvement in the stability of a protein.     

Host tree unsuitability recognized by pine shoot beetles in flight

Summary In spring, the landing rate of flying European pine shoot beetles,Tomicus piniperda L., on injured Scots pine diminishes as colonization continues. This is due to olfactory cues that indicate progressive host degradation. Verbenone was shown to play a role in the beetle's recognition of this unsuitability of a formerly suitable host, since the compound was increasingly released from colonized tree sections as they aged, but not from uninfested sections. Also, the release of verbenone at natural rates in the forest inhibited the attraction of beetles to host monoterpenes.     

Demonstration of retinoic acid isomers in human urine under physiological conditions

Untransformed retinoic acid has never been demonstrated in human excreta under normal physiological conditions. We have developed a two-step liquid chromatographic system for the demonstration of subnanogram amounts of this compound in human urine without administration of any precursor.     

Uninterrupted protein synthesis is essential for survival in the early stages of carbontetrachloride-induced hepatocellular necrosis in the mouse

Summary The fatal syndrome produced by cycloheximide given 6 h after a hepatonecrogenic dose of CCl₄ is due neither to direct toxic synergism between CCl₄ and cycloheximide nor to transient sinusoidal thrombosis. It is suggested that survival in the presence of unknown factors released from dying liver cells requires uninterrupted protein synthesis. The life-saving effect of sterilization of the intestine by antibiotics indicates that the gut flora or its products play a vital role in pathogenesis.Acknowledgments. I wish to thank Mr C. R. West for carrying out the statistical analysis, Mrs Brenda Brooks for histological processing, and Berk Pharmaceuticals Ltd for information on Ancrod defibrination in mice.