An investigation into the effect of seasonal root replacement upon plant longevity in perennial ryegrass (Lolium Perenne), Italian ryegrass (L. multiflorum), tall fescue (Festuca arundinacea) and annual meadow grass (Poa annua) : a thesis presented at Massey Agricultural College in part fulfillment of the requirements for the degree of Master of Agricultural Science in the University of New Zealand

Best copy available.Any reader of the American news magazine, "Time", will know that the editors occasionally publish a "grass roots report" dealing with some current question of public interest. It takes the form of a survey of the fundamental issues involved, and attempts to assess their significance, in-so-far as those issues are known. It is a tacit recognition by a non-scientific body of opinion of the importance of the underground organs to the well-being of a plant, and that these organs are more essential, despite their hidden and inaccessible habitat, than is commonly recognized. [From Introduction

Racemisation and human cataract. d-Ser, d-Asp/Asn and d-Thr are higher in the lifelong proteins of cataract lenses than in age-matched normal lenses

Several amino acids were found to undergo progressive age-dependent racemisation in the lifelong proteins of normal human lenses. The two most highly racemised were Ser and Asx. By age 70, 4.5% of all Ser residues had been racemised, along with >9% of Asx residues. Such a high level of inversion, equivalent to between 2 and 3 d - amino acids per polypeptide chain, is likely to induce significant denaturation of the crystallins in aged lenses. Thr, Glx and Phe underwent age-dependent racemisation to a smaller degree. In model experiments, d - amino acid content could be increased simply by exposing intact lenses to elevated temperature. In cataract lenses, the extent of racemisation of Ser, Asx and Thr residues was significantly greater than for age-matched normal lenses. This was true, even for cataract lenses removed from patients at the earliest ages where age-related cataract is observed clinically. Racemisation of amino acids in crystallins may arise due to prolonged exposure of these proteins to ocular temperatures and increased levels of racemisation may play a significant role in the opacification of human lenses