pel (Abbott Laboratories, North Chicago, Ill.); B. thuringiensis subsp. alesti was a gift from P.

Glycopeptides were isolated from the cell surfaces of mouse brain cortical tissue that inhibited both cell division and protein synthesis by cells in culture. The protein-synthesis inhibition appeared to affect most cells exposed and was equally effective against glycoprotein and protein synthesis. The inhibition of protein metabolism was independent of mRNA synthesis and uptake of labelled precursors into intracellular pools, indicating that it was directed at intracellular translational events. Fractionation of chloroform/methanol-extracted preparations of this brain cell-surface substance on Bio-Gel P-100 revealed the material to be quite heterogenous, although inhibitory activity was found only in fractions of mol.wt. 25000--30000 and 6000--10000. Biochemical analysis of these fractions demonstrated that they were 6% carbohydrate and 94% amino acid by weight. The 25000--30000-mol.wt. glycopeptides were shown to inhibit cell growth at concentrations of 2 microgram/ml in cultured cells and to inhibit protein synthesis by 50% at concentrations of 3 microgram/ml. The 25000--30000-mol.wt. brain-cell-surface-substance glycopeptides were further purified by ultrafiltration and affinity chromatography with Ulex europaeus agglutinin, resulting in a 400-fold increase in specific biological activity. The inhibitor was not lethal to cells and was not species- or tissue-specific.

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Major ethanol-soluble carbohydrate and organic acid constituents of white clover (Trifolium repens) have been identified by use of high-performance liquid chromatography and gas chromatography. In leaves, petioles, roots, and nodules, pinitol (3-0-methyl chiro-inositol) is the predominant sugar, with sucrose present in lower concentration. In leaves and petioles there are significant levels of a-and fl-methyl glucosides, linamarin, glucose, and fructose. In the nodules glucose is rarely present at detectable levels. The concentration of pinitol is generally greater than 25 millimolar in each tissue examined whereas the level of sucrose varies depending on the time of day. Sucrose is the major sugar significantly labeled during 1 hour administration of '4C02 and accounts for more than 99%o of al the radioactivity detected in the nodules at early times. Between 3 and 7 hours after labeling, 6% of the radioactivity is found in the organic acids fraction and 5% in the basic fraction of nodules. Malonic acid does not appear to be present in unusually high concentrations in either leaves or nodules of white clover.Considerable effort has been expended to identify the major ethanol-soluble carbohydrates (hereafter referred to as sugars) and organic acid constituents of soybean, an economically important legume (5-7, 13, 14, 17, 19-22). Much less has been done with other legumes (1, 18). We have examined white clover (Trifolium repens L.) because it is a convenient test organism for studies of the fast-growing Rhizobium trifolii. It has been much easier to induce expression of nitrogenase ex planta with the slow-growing brady rhizobia (16) than with the fast growers, and the fast growers may have different requirements for symbiotic induction that can be met only by particular species of legumes. We suspected that clover might contain a specific carbon substrate needed for expression of nitrogenase activity by R. trifolii.Phillips and Smith (17) reported that soybean (Glycine max [L.] Merr.) and other legumes contained high levels of a methyl inositol. Streeter (19,20) showed that this compound was D-pinitol (3-0-methyl chiro-inositol) and studied its seasonal appearance and disappearance in soybeans. Other sugars present in significant quantities included myo-inositol, sucrose, fructose, and glucose.Smith and Phillips (18) reported the presence of 1-0-methyl f-Dglucopyranoside in leaves and petioles of white clover. Linamarin, a cyanogenic glucoside, is also present in these tissues (12).Stumpf and Burris examined the organic acid constituents of soybean and found that malonic acid was a major constituent (21). Lower levels of the Krebs cycle acids also were present and readily detected in leaves and nodules. Malonic acid was rapidly labeled by feeding "CO2 to root nodules (22).In agreement with Phillips and Smith (17), we have found the ' Supported by the Kansas Agricultural Experiment Station, contribution 83-29-j. methyl inositol, pinitol, to be present at high concentrations in white clover. We also found ...