Jacques Mayaudon

Isolation of protein from humic acid extracted from soil

SummaryChromatography of humic acid in a phenol containing solvent system reveals, in the case of the three types of soil analyzed, the presence of humoprotein containing 11 per cent of nitrogen. Isolation of a humoprotein complex from humic acid, according to the method used by Kirby, followed by paper chromatography allowed the isolation of a protein fraction containing 14.8 per cent nitrogen. This fraction is not dialysable; it has a maximum absorption in ultraviolet light between 260–280 mµ, a small electronegative charge and gives rise to twenty different amino acids. This is the first time that a protein has been separated from humus. Thereby demonstrating that part of the nitrogen contained in humic acid is in the form of protein protected from decomposition.

Extraction and study of soil enzymes metabolising tryptophan

SummaryThe dialysed humic acids obtained from a forest Mull by extraction of a diluted solution of sodium carbonate are enzymatically active.It is found by radiorespirometry that the humic acids act on thel-tryptophan carboxyl C14, although thed-tryptophan carboxyl suffers no attack. The methylene group and the indole and benzene nuclei are not broken down. Only the carboxyl function is mineralised.Radiochromatography shows that through the action of the humic acids the tryptophan is broken down primarily into indoleacetamide and secondarily into β-indoleacetic acid. From the nature of these compounds it is assumed that the humic acids have an oxygenas effect on thel-tryptophan.The enzymatic activity has its optimum value at 65°C. It is partially inhibited by lyophilisation and by toluene. The pyridoxal phosphate (0.1 µM) has a slight activating influence. The alkalis and mineral acids decompose the enzyme.We can therefore see just how much importance attaches to the humic matter, not only as an energy substrate reserve for the micro-organisms and plants but also as a site for biological activities which are quite distinct from any microbial proliferation and the role of which in plants has still to be studied.It would be of interest to determine the presence of this enzymatic system in other pedologically defined soils and to study it in correlation with their fertility. In addition, there remains the task of detecting the microbial agents in the soil which contribute to the formation of this remarkable enzymatic system.

Rate of 14CO2 production from variously labeled forms of [14C]glucose in human breast invasive ductal carcinoma tissues.

To establish possible cancerous aggressiveness between the metabolism of variously labeled [14C]glucose in the human breast invasive ductal carcinoma (IDC) tissues, we measured the rates of 14CO2 production from those tissues by using radiorespirometry, expressing the results as initial velocity (V) in nanomoles of 14CO2 min‐1 g‐1 of fresh tissues. The Vc data were compared with results of the SBR system, which grades up from I to III. Vc,1 values measured with [1‐14C]glucose increased from 1.99‐2.82 for SBR I to 3.90‐4.09 for SBR II, finally reaching 4.83‐7.04 for SBR III, thus matching clearly the increase of IDC cancerous aggressiveness. Conversely, data obtained from [3,4‐14C]glucose and [6‐14C]glucose decreased with increasing cancer stage: i.e., with [3,4‐14C]glucose, Vc,3,4 values were 5.79‐9.34 for SBR I, 4.45‐4.84 for SBR II, and 2.35‐1.90 for SBR III; with [6‐14C]glucose, the corresponding Vc,6 values were 1.34‐1.90, 1.33‐1.41, and 0.72‐0.79. The Vn,1/Vn,6 ratios were close to unity for normal tissues and for noncancerous tissues surrounding SBRI tumors. For cancerous tissues, however, the Vc,1/Vc,6 ratios were 1.5, 2.9, and 6.1‐9.8 in IDC tissues graded as SBR I, II, and III, respectively. The results suggest the possible use of radiorespirometry as a tool to assess IDC aggressiveness.

A proposed estimate of the tumor aggressiveness of human breast cancer using radiorespirometry

The relationships between carcinomatous aggressiveness and the glucolytic metabolism, namely the rate of 14CO2 production from [U‐14C] glucose, are obtained from human breast tissues using radiorespirometry. The values are estimated as the initial velocity (V) expressed in η14CO2×min‐1×g‐1 of fresh tissues by [U‐14C] glucose metabolism. The aggressiveness of the breast carcinomatous is diagnosed by the SBR grade system. As two control normal tissues, (V) are 0.86 to 0.90 from non‐cancer patients. In carcinomatous tissues (Vc), there is an increase from 1.53 to 3.14, but in the corresponding surrounding non‐cancer tissues (Vn) these show a decrease from 2.20 to 0.22 for SBR I, SNR II to SBR III. The ratio between (Vc) and (Vn) are found, according to carcinomatous aggressiveness, as 1.45 to 1.54, 1.69, 2.35 to 2.86 and 4.82 to 10.38 respectively for SBR I, lobular carcinoma, SBR II and SBR III; while the ratio is 1.04 for the normal tissue which come from non‐cancer patients. The above results suggest the possibility of assessing the carcinomatous aggressiveness by radiorespirometry before a histopathological diagnosis, even in a lower aggressiveness as in SBR I cases which are difficult to diagnose and manage.