The correlation between pollen/ovule (P/O) ratio and breeding system has generally been accounted for either on the basis that P/O reflects pollination efficiency, or in terms of the sex allocation theory. The following were assessed for taxa belonging to genus Astragalus subgenus Epiglottis: 1) Degree of correlation between P/O and the breeding system, measured by means of autofertility; 2) The absence or existence of correlation between P/O and pollen grain size; and 3) The ability of various theories to account for the results obtained. Results showed a minimal correlation between P/O and autofertility, and between P/O and pollen grain size in the taxa studied. Analysis of these results in terms of the sex allocation theory enabled this correlation to be explained as a function of the variation existing between taxa with respect to the resources invested in each pollen grain and in each ovule. The predictive capacity of this theory, which has moreover proven valuable in explaining the structural peculiarities of the androecium in these taxa, was also highlighted. The type of self‐pollination applicable was also discussed, as was the phenotypic model of selection of self‐fertilization considered most plausible for these taxa.

An L-amino-acid oxidase (EC 1.4.3.1) that catalyzes the oxidative deamination of twelve L-amino acids has been purified 21-fold and with 14% yield to electrophoretic homogeneity from Chlamydomonas reinhardtii cells by ammonium-sulfate fractionation, gel filtration through Sephacryl and Superose, anion-exchange chromatography and preparative electrophoresis in polyacrylamide gels. The native enzyme is a protein of 470 kDa and consists of eight identical or similarsized subunits of 60 kDa each. Optimum pH and temperature were 8.2 and 55° C, respectively, with a Q10 (45-55° C) of 1.7 and an activation energy of 45 kJ · mol(-1). Its absorption spectrum showed, in the visible region, maxima at 360 and 444 nm, characteristic of a flavoprotein with a calculated flavin content of 7.7 mol FAD per mol of native enzyme. Apparent K m values of the twelve L-amino acids which can act as substrates of L-amino-acid oxidase ranged between 31 μM for phenylalanine and 176 μM for methionine. The effect of several specific group reagents, chelating agents and bivalent cations on enzyme activity has also been studied.

The correlation between pollenlovule (P/O) ratio and breeding system has generally been accounted for either on the basis that P/O reflects pollination efficiency, or in terms of the sex allocation theory. The following were assessed for taxa belonging to genus Astragalus subgenus Epiglottis: I) Degree of correlation between P/O and the breeding system, measured by means of autofertility; 2) The absence or existence of correlation between P/O and pollen grain size; and 3) The ability of various theories to account for the results obtained. Results showed a minimal correlation between P/O and autofertility, and between P/O and pollen grain size in the taxa studied. Analysis of these results in terms of the sex allocation theory enabled this correlation to be explained as a function of the variation existing between taxa with respect to the resources invested in each pollen grain and in each ovule. The predictive capacity ofthis theory, which has moreover proven valuable in explaining the structural peculiarities of the androecium in these taxa, was also highlighted. The type of self-pollination applicable was also discussed, as was the phenotypic model of selection of self-fertilization considered most plausible for these taxa.

BackgroundSupplementing mice with high levels of dietary n-3 polyunsaturated fatty acids (PUFAs) increases the n-3 PUFAs in cell membranes, increases the susceptibility of the cells for lipid peroxidation (LPO) and decreases the growth rate of mammary and other tumors. However, the results of an earlier study indicated that a factor in addition to LPO was involved in the reduction in tumor growth in n-3 PUFAs fed mice. Athymic mice bearing MDA-MB-231 human breast carcinoma xenografts, were fed fish oil concentrate (FOC) or control diets, with and without supplemental Vitamin E (2000 IU /kg diet) and were sacrificed both before and after doxorubicin (DOX) treatment to evaluate factors involved in tumor growth suppression.ResultsPrior to DOX, basal LPO in the tumor of 3% FOC fed mice was slightly higher than in the control fed mice and was decreased in mice consuming FOC with vitamin E. Vitamin E suppressed the DOX induced increase in LPO in the tumors of control mice, however, vitamin E was not sufficient to suppress a DOX induced increase in LPO in the tumors of FOC fed mice. The mean growth rate of tumors of FOC fed mice was significantly less than the mean growth rate of the tumors of control mice. Multiple regression analyses indicated that suppression of glutathione peroxidase (GPX) activity by FOC prior to DOX therapy was more important than increased LPO as an explanation of tumor growth suppression. Tumor induced cachexia was decreased in mice consuming FOC.ConclusionsIt appears that the increased sensitivity to DOX was related to an FOC induced reduction in GPX activity. FOC reduced tumor induced cachexia.

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