Shelly G. Yates

Bio: Shelly G. Yates is an academic researcher. The author has contributed to research in topics: Festuca arundinacea & Ergovaline. The author has an hindex of 10, co-authored 10 publications receiving 633 citations.

Analysis of loline alkaloids in endophyte-infected tall fescue by capillary gas chromatography

Abstract: A capillary gas chromatographic method for routine analysis of loline-type alkaloids in tall fescue seed and forage has been developed. Filtered solvent extracts of seed, in CH,Cl,/MeOH/NH,OH (75:25:0.5), with phenylmorpholine as an internal standard were normally suitable for direct GC analysis; however, forage extracts required additional cleanup by ion exchange to remove interfering substances. Peak identities were confirmed by mass spectrometry and comparison to known standards. The method should be useful in studies concerning the relationships between loline alkaloid concentration in grasses, insect resistance, and performance problems in cattle. Tall fescue, Festuca arundinacea Schreb, is a coolseason pasture grass that is used extensively in the southeastern United States. Most existing pastures are infected with an endophytic fungus, Acremonium coenophialum Morgan Jones and Gams, and A. coenophialum infected tall fescue is known to contain a variety of alkaloids (Figure 1). The ergot-type alkaloids, such as ergovaline and ergonovine, and the loline-type alkaloids, mainly Nformyl- and N-acetylloline, have not been found in tall fescue when the endophyte is absent. These two classes of alkaloids have been associated with production losses in cattle (Sanchez, 1987), and economic losses to cattle producers have been estimated at $50 to $200 million annually (Siege1 et al., 1984).

Isolation, semi-synthesis, and NMR spectral studies of loline alkaloids

Abstract: Loline, a saturated pyrrolizidine-type alkaloid, was isolated from tall fescue (Festuca arundinacea) seed infected with the endophytic fungus Acremonium coenophialum. Procedures are described for the efficient conversion of loline to derivatives also known to occur naturally. The loline akaloids are of interest as they are suspected contributors to several disease syndromes in cattle that consume endophypte-infected tall fescue

Evolutionary origins and ecological consequences of endophyte symbiosis with grasses.

Abstract: Over the past 20 yr much has been learned about a unique symbiotic interaction between fungal endophytes and grasses. The fungi (Clavicipitaceae, Ascomycota) grow intercellularly and systemically in aboveground plant parts. Vertically transmitted asexual endophytes forming asymptomatic infections of cool‐season grasses have been repeatedly derived from sexual species that abort host inflorescences. The phylogenetic distribution of seed‐transmitted endophytes is strongly suggestive of cocladogenesis with their hosts. Molecular evidence indicates that many seed‐transmitted endophytes are interspecific hybrids. Superinfection may result in hyphal fusion and parasexual recombination. Most endophytes produce one or more alkaloid classes that likely play some role in defending the host plant against pests. Hybridization may have led to the proliferation of alkaloid‐production genes among asexual endophytes, favoring hybrids. The ergot alkaloid ergovaline, lolitrems, and lolines are produced by only a ...

Chemistry, Biochemistry, and Dietary Role of Potato Polyphenols. A Review

Abstract: Potatoes and other plant foods accumulate a variety of secondary metabolites, including phenolic compounds, phytoalexins, protease inhibitors, and glycoalkaloids, as a protection against adverse effects of mechanical bruising, light, and injury by predators including beetles, fungi, and insects. Since these phytochemicals are consumed by insects, animals, and humans as part of their normal diet, a need exists to develop a better understanding of the role of these compounds in both the plant and the diet. To contribute to this effort, this multidisciplinary overview describes analytical and compositional aspects of phenolic compounds in potatoes; their biosynthesis, molecular genetics, and role in host-plant resistance relationships; bruising-, ferrous ion-, and heat-induced discolorations such as after-cooking blackening and blackspot formation, which affect appearance and sensory properties of potatoes; polyphenol-oxidase-catalyzed enzymatic browning reactions and their prevention by chemical and plant m...

Why Fruits Rot, Seeds Mold, and Meat Spoils

Abstract: When an animal eats "spoiled" or "rotten" food of any kind, it runs a largely unknown risk (except in the case of grains) of being injured by toxins or microbe-produced antibiotics, getting food wi...

Fungal endophyte-infected grasses: Alkaloid accumulation and aphid response.

Abstract: The occurrence of the alkaloidsN-formyl andN-acetyl loline, peramine, lolitrem B, and ergovaline and the response of aphids to plants containing these compounds were determined in species and cultivars ofFestuca,Lolium, and other grass genera infected with fungal endophytes (Acremonium spp., andEpichloe typhina). Twenty-nine of 34 host-fungus associations produced one or more of the alkaloids, most frequently peramine or ergovaline. Three alkaloids (lolines, peramine, and ergovaline) were found in tall fescue and in perennial ryegrass infected withA. coenophialum, while peramine, lolitrem B, and ergovaline were present in perennial ryegrass and in tall fescue infected withA. lolii and inF. longifolia infected withE. typhina. WhileA. coenophialum andA. lolii produced similar patterns of alkaloids regardless of the species or cultivar of grass they infected, isolates ofE. typhina produced either no alkaloids or only one or two different alkaloids in the grasses tested. Aphid bioassays indicated thatRhopalosiphum padi andSchizaphis graminum did not survive on grasses containing loline alkaloids and thatS. graminum did not survive on peramine-containing grasses. Ergovaline-containing grasses did not affect either aphid.

Occurrence of peptide and clavine ergot alkaloids in tall fescue grass.

Abstract: Evidence is presented that ergot alkaloids are ubiquitous in tall fescue pastures infected with the clavicipitaceous fungal endophyte Sphacelia typhina (or Acremonium coenophialum). Ergopeptide alkaloids, predominantly ergovaline, constituted 10 to 50 percent of the total ergot alkaloid concentration, which was as high as 14 milligrams per kilogram in sheaths and 1.5 milligrams per kilogram in blades. Ergot alkaloid concentrations were substantially increased by application of large amounts (10 millimoles per liter) of potassium nitrate or ammonium chloride to infected plants in the greenhouse. The results indicate that ergot alkaloids are probably responsible for the toxicity to cattle of this common pasture and lawn grass and that ergotism-like toxicoses may be caused by clavicipitaceous fungi other than Claviceps.