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Results for “Ilex vomitoria”

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PubMed1999

Sugar feeding by Culicoides mississippiensis (Diptera: Ceratopogonidae) on the yaupon holly, Ilex vomitoria.

Adult Culicoides mississippiensis Hoffman were collected from 5 flowering yaupon holly plants at sunrise, late morning, early afternoon, and sunset from 5 flowering yaupon holly plants during the entire flowering season (16 March-15 April 1995). Individual insects were tested for fructose by using the cold anthrone test. Prevalence of fructose in C. mississippiensis was 55.6% (427 of 768), with positivity for gravid females greater than for males. Fructose positive rates decreased in gravid females from morning to evening, whereas male rates were constant until evening, when they decreased. Both sugar feeding by gravid females and host-seeking by parous females were highest at sunset, followed by sunrise.

Animals↗

PubMed2004

An improved thin-layer chromatography/mass spectrometry coupling using a surface sampling probe electrospray ion trap system.

A combined surface sampling probe/electrospray emitter coupled with an ion trap mass spectrometer was used for the direct read out of unmodified reversed-phase C18 thin-layer chromatography (TLC) plates. The operation of the surface sampling electrospray ionization interface in positive and negative ionization modes was demonstrated through the direct analysis of TLC plates on which a commercial test mix comprised of four dye compounds viz., rhodamine B, fluorescein, naphthol blue black, and fast green FCF, and an extract of the caffeine-containing plant Ilex vomitoria, were spotted and developed. Acquisition of full-scan mass spectra and automated collection of MS/MS product ion spectra while scanning a development lane along the surface of a TLC plate demonstrated the advantages of using an ion trap in this combination. Details of the sampling system, benefits of analyzing a developed lane in both positive ion and negative ion modes, levels of detection while surface scanning, surface scan speed effects, and the utility of three-dimensional data display, are also discussed.

Amido Black↗

PubMed2006

Nitrogen fertilizer and gender effects on the secondary metabolism of yaupon, a caffeine-containing North American holly.

Yaupon (Ilex vomitoria) is a caffeine-containing dioecious shrub native to the southeastern United States that was historically brewed into a stimulating beverage. We tested predictions of the carbon/nutrient balance (CNB) hypothesis by determining whether nitrogen availability and gender influence production of caffeine and related alkaloids as well as phenolic compounds in leaves of pot-grown yaupon plants fertilized with ammonium nitrate. The CNB hypothesis predicts that additional nitrogen should result in increased alkaloid concentrations and decreased phenolic concentrations. An extension of the CNB hypothesis to dioecious plants predicts that females have higher C/N ratios and therefore higher phenolic concentrations and lower alkaloid concentrations than male conspecifics. In our study, caffeine and total alkaloid concentrations were 5-10 times higher in fertilized than control plants but did not vary by gender. Nevertheless, an observed interaction between gender and fertilization suggests that females respond more to fertilization than males in caffeine production. In addition, fertilized plants not only contained higher concentrations of alkaloids and total nitrogen but also allocated a larger proportion of their nitrogen to alkaloid production than control plants. Total phenolic concentrations were higher in control females than control males as predicted by the CNB hypothesis, but did not vary by treatment nor were there differences by gender among fertilized plants. We also found high correlations between antioxidant capacity and both classes of phenolic compounds detected in our study (cinnamic acid derivatives and flavonoids) indicating that in addition to their putative defensive function against herbivores, phenolics protect yaupon from oxidative stress. Explanation of the inconsistencies between our data and predictions of the CNB hypothesis may benefit from a re-appraisal of the physiological mechanisms by which resource availability affects secondary metabolism as well as consideration of the selective pressures to which secondary metabolism responds.

Alkaloids↗