Ralph O. Mumma

RNA isolation from recalcitrant plant tissue

The isolation of high-quality RNA from various tissues (leaves, pedicels, glandular trichomes) of garden geranium (Pelargonium xhortorum) using various published methods is difficult due to numerous oxidizing compounds. A new RNA extraction method was developed through the combination and modification of two separate procedures (Rochester et al., 1986; Manning 1991). In addition to geranium tissues, this method is successful when used with other recalcitrant tissues such as mature needles of white pine (Pinus strobus) and mature leaves of poinsettia (Euphorbia pulcherrima). RNA quality was judged by spectrophotometric readings, denaturing agarose gels, and successful reverse transcription.

National survey of elements and other constituents in municipal sewage sludges

Fifty-nine elements, poly chlorinated biphenyls, volatile N-nitrosamines and gamma emission were determined in 30 sewage sludges from 23 American cities using several analytical methods. Relatively high concentrations of toxic metals were found in sludges from specific municipal plants. The pH and levels of calcium and iron in certain of the sludges appeared to reflect the addition of lime, ferric chloride and/or spent pickle liquor during sewage treatment. Of 15 sludges analyzed, the carcinogen, N-nitrosodimethylamine was detected in 14 and various other N-nitrosamines in 12 of them. Based on present federal guidelines, only 7 of the 30 municipal sludges analyzed would be considered suitable for land application owing to their elevated content of one or more heavy metals.

The lipids of thermophilic fungi: Lipid composition comparisons between thermophilic and mesophilic fungi

The lipid composition of nine thermophilic and nine mesophilic species of seven genera of fungi were compared. The total lipids varied between 8.0% and 54.1% with most fungi possessing between 8.0% and 18.3% lipids. The predominant fatty acids were found to be palmitic, oleic and linolenic. Lesser amounts of arachidic, linolenic, palmitoleic, pentadecanoic, myristic and lauric acids were found. The mesophiles varied between 0% and 18.5% linolenic acid, while the thermophiles did not contain any appreciable linolenic acid (<0.5%). The mesophile,Mucor globosus, and the thermophile,Mucor pusillus, contain γ linolenic acid. The fatty acids of the thermophilic fungi were more saturated than the corresponding mesophilic species.

Preparation of sulfate esters.

This communication reports a new method for the synthesis of sulfate esters, in good yield, under mild conditions. Sulfuric acid reacts with an alcohol and dicyclohexylcarbodiimide in a polar solvent to produce sulfate esters.

The lipids of Pythium ultimum

Abstract The lipids of the oomycete, Pythium ultimum Trow, grown under controlled environmental conditions, were identified and quantitatively determined. Lipid composition data are presented on the fungus grown at both 20° and 30° for a period of 14 days. The fungus contained from 3 to 48% total lipid depending upon its stage of growth. The triglycerides were most abundant, with lesser amounts of free fatty acids, phosphatides and monoglycerides. The major phosphatides were phosphatidyl choline, phosphatidyl ethanolamine, lysophosphatidyl ethanolamine and phosphatidyl glycerol. There were smaller amounts of diphosphatidyl glycerol, phosphatidyl inositol, phosphatidic acid and lysophosphatidyl choline. The major fatty acids were palmitic, oleic, linoleic, docosenoic, and docosadienoic acid. The fatty acid composition of the individual lipid classes was also examined.

Inhibition of lipoxygenase and prostaglandin endoperoxide synthase by anacardic acids

C22:1 omega 5-anacardic acid was found to be a good inhibitor of both potato lipoxygenase and ovine prostaglandin endoperoxide synthase with approximate IC50s of 6 and 27 microM, respectively. Very similar inhibition was seen with the crude exudate, rich in omega 5-anacardic acids, from glandular trichomes of an arthropod-resistant strain of geranium, Pelargonium xhortorum. The saturated anacardic acid (C22:0 sat), abundant in the trichome exudate of susceptible strains, was nearly as inhibitory toward both prostaglandin endoperoxide synthase and lipoxygenase as the omega 5-unsaturated compound. However, the dimethyl derivative of C22:1 omega 5-anacardic acid was a poor inhibitor of prostaglandin endoperoxide synthase and caused only moderate (32%) inhibition of lipoxygenase even at 135 microM. The possible role of prostaglandin endoperoxide synthase and lipoxygenase inhibition in the enhanced pest resistance of geraniums which produce the omega 5-AnAs is discussed.

Leaching and runoff losses of herbicides in a tilled and untilled field

Abstract Transport of herbicide mass by leaching and runoff was evaluated over several years. Herbicides were applied at recommended rates to conventional tillage (CT) and no-tillage (NT) planted corn (Zea mays L.) fields on Hagerstown silty clay loam (Typic Hapludalf). Pre-emergence herbicide treatments on each tillage system included simazine (6-chloro-N,N′-diethyl-1, 3,5-triazine-2,4-diamine), atrazine (6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine), cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropanenitrile) and metolachor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide). Application rates (active ingredient basis) were 1.7 kg ha−1 (simazine, atrazine) and 2.2 kg ha−1 (cyanazine, metolachlor). Percent herbicide losses (1984–1988) in root zone leachates, sampled in pan lysimeters embedded 122 cm deep in the soil profile, were greater under NT than under CT corn production. The opposite was true for runoff losses of herbicides and the magnitude of loss was less for runoff than for leaching. Total percolate yield and spray date-leaching or runoff event intervals were critical factors controlling surface or subsurface herbicide “loadings” in water. Areal losses were directly related to percolate or runoff yield and inversely related to these time increments. Also, unusually dry conditions in 1988 increased the soil residence time for cyanazine, resulting in a late-season leaching pattern somewhat atypical for this low persistence herbicide. During the 5 years, average CT leaching losses calculated from herbicide concentrations and lysimeter percolate volumes, collected in several pits, ranged from less than 0.01 to 1.05% of sprayed amounts. The more persistent herbicides, atrazine and simazine, were generally at the upper level of this range. Under NT conditions, average leaching losses ranged from 0.05 to 6.16% of sprayed amounts. Cyanazine losses were equal to or greater than simazine and atrazine losses in several seasons. In general, metolachor was the least mobile herbicide. Runoff losses (3–5% slope) were greatest in 1985 and 1986 for simazine under CT (0.62 and 0.51% of the applied rate, respectively). Respective losses under NT were 0.18% and less than 0.01%.

Isolation of ascorbic acid 2-sulfate from selected rat organs

Abstract Rats were injected subcutaneously with 35 SO 4 2− and [1- 14 C]ascorbic acid. A compound was isolated from rat liver and spleen which had chromatographic properties identical to synthetic ascorbic acid 2-sulfate (AAS). This compound gave a positive methanolic FeCl 3 reaction, contained radioactive sulfur, and on hydrolysis it degraded to 35 SO 4 2t- and [ 14 C]ascorbic acid. The isolated compound possessed identical λ max ultraviolet absorption to that of AAS and co-crystallized with standard AAS to constant specific activity. These data collectively indicate the isolated compound was AAS. Quantitation by ultraviolet techniques indicated the liver possessed a concentration of 369 μM AAS. Radiochemical and chromatographic evidence is also presented for the presence of AAS in rat urine and adrenal glands.

SHIELD DEFENSE OF A LARVAL TORTOISE BEETLE

Larvae of the folivorous tortoise beetle, Plagiometriona clavata, carry shields formed from feces and exuviae above their bodies. We used an ecologically relevant predatory ant, Formica subsericea, in a bioassay to determine if shields functioned as simple barriers, as previous studies indicated, or whether they were chemical defenses. Shields were necessary for larval survival; shield removal rendered larvae vulnerable. Shields produced by larvae reared on a substitute diet failed to provide protection. Solvent-leached shields also failed to deter ants, indicating the shield had a host-derived chemical component likely located in the feces, not in the exuviae. Solanum dulcamara, the larval host plant, contained free phytol, steroidal glycoalkaloids, and saponins. Shields contained partially deglycosylated metabolites of host steroidal glycoalkaloids and saponins, a suite of fatty acids, and derivatives of phytol, which together formed a deterrent barrier against ant attack. We compared the mobile shield of P. clavata to the stationary shield of another S. dulcamara-feeding leaf beetle, Lema trilinea. Both larval shield defenses were formed from a very similar array of host-derived compounds with deterrent properties. We concluded that convergent patterns of limited chemical transformation and selective incorporation of particular deterrent metabolites in shield defenses of two unrelated taxa represented responses to selection from invertebrate predators.

Analysis of trichome exudate from mite-resistant geraniums.

Trichome exudate from mite-resistant geraniums (Pelargonium horlorum) was analyzed, principally by mass spectrometry and NMR spectroscopy. The exudate was found to consist of two anacardic acid derivatives,o-pentadecenylsalicylic acid ando-heptadecenylsalicylic acid. Bioassays established a moderate toxicity of these compounds to the two-spotted spider mite,Tetranychus urticae. The production of these compounds in geraniums was correlated with the two complementary dominant genes previously reported for host resistance to spider mites.