Concentration Of Phenolic Substances Research Articles

STUDIES ON THE STRUCTURE OF THE FEMALE REPRODUCTIVE SYSTEM AND EGG-SHELL FORMATION IN ASPICULURIS TETRAPTERA SCHULZ, (NEMATODA: OXYUROIDEA).

The histological anatomy of the female reproductive system of an oxyuroid nematode,Aspiculuris tetraptera, Schulz, has been described.The process of egg-shell formation in this animal has been followed in detail while the structural and chemical characteristics of the egg-shell have been studied by histochemical and other methods. It is shown that there are three layers: a lipoprotein layer, a ‘chitinous’ layer and the so-called vitelline (glycosidal) membrane. Evidence is presented for the exogenous origin of the lipoprotein layer: this being formed by the cells of the upper uterus which are shown to be secretory.The question of quinone-tanning in the egg-shell ofA. tetrapteraand in other oxyuroids and ascarids is considered. It is shown that neither a polyphenol oxidase nor a high concentration of phenolic substances (apart from protein tyrosine) exists in this system. The significance of these and other observations is discussed in relation to the mechanism of tanning as elucidated in insects and trematodes.I have to acknowledge with gratitude the support of many during these investigations. To Dr P. Tate for his encouragement and provision of facilities at the Molteno Institute; to Dr D. L. Lee, for much useful discussion and permission to refer to some of his unpublished electron micrographs of nematodes; to Professor J. D. Smyth, who kindly read through the manuscript; to the Cambridge Philosophical Society for a grant that made possible the translation of Fauré-Frémiet's classical study onAscaris;and to the Department of Technical Cooperation for financial assistance.

Relation of Arbutin-Hydroquinone in Pear Blossoms to Invasion by E. amylovora

INFECTION of plants by certain virus and fungus pathogens results in an increase in polyphenol synthesis and oxidation1,2. This has been interpreted as a possible defence reaction by host tissue. Investigations of resistance of specific varieties of pear, Pyrus communis, to invasion by Venturia pirina indicated that polyphenol metabolism might be associated with resistance3. A project was initiated to determine whether the location and concentration of phenolic substances in pear might be of possible significance in influencing the channels of infection and relative susceptibility of specific pear tissues to fire blight caused by Erwinia amylovora. The relation of the arbutin-hydroquinone complex in pear blossoms to invasion by the fire blight organism is herein reported.

THE PATHOGENICITY OF PRATYLENCHUS PENETRANS TO STRAWBERRY

Under aseptic conditions, Pratylenchus penetrans (Cobb, 1917) Filip. & Stek., 1941, was pathogenic to roots of strawberry seedlings. After penetrating the epidermis, the nematodes aligned themselves with the long axis of the root at various depths in the cortical parenchyma. Although the endodermis was not invaded by the nematode, it was the first tissue to become discolored. Later, a less intense discoloration was observed in the cortex and epidermis, with the formation of polyderm beneath the damaged endodermis. The intensity of discoloration may be associated with the concentration of phenolic substances in the different tissues.

Studies On the Host-Parasite Relations of Pratylenchus Penetrans (Cobb) To Apple Seedlings

A technique is described for the inoculation, under aseptic conditions, of apple seedlings with the root lesion nematode Pratylenchus penetrans (Cobb, 1917) Filip. & Stek., 1941. Under these conditions apple feeder roots (i.e. those without secondary thickening) react to nematode invasion by a rapid discolouration of the outermost, (i.e. epidermis and hypodermis) and innermost, (i.e. inner cortex and endodermis) cortical tissues, but show little or no reaction in the intervening cortical parenchyma. This response is compared with that of peach roots, in which all the cortical tissues are readily discoloured by this nematode. Histochemical tests suggest that sensitivity to P. penetrans is correlated with the presence and concentration of phenolic substances in the various tissues of these two hosts.