Many of the extraction and amino acid analysis methodologies currently employed do not provide complete analysis of all the physiological amino acids and biogenic amines. Extraction procedures frequently employ dilute...Many of the extraction and amino acid analysis methodologies currently employed do not provide complete analysis of all the physiological amino acids and biogenic amines. Extraction procedures frequently employ dilute acid which partially converts gln and asn to glu and asp. A commonly used pre-column derivatizing agent, o-phthalaldehyde, does not react with the imino acids, pro and hydroxypro. The purpose of this investigation was to integrate extraction and analysis procedures into a reliable method for measuring the complete physiological amino acid profiles of fruit and vegetables using HPLC instrumentation commonly available to most laboratories. Water extraction of ground, frozen-thawed tissues effected complete recovery of the physiological amino acids as demonstrated by spiking experiments and tissue combination experiments. HPLC of dabsyl derivatives of the free amino acids allowed their quantification in a selection of fruit and vegetables. Physiological amino acid levels were determined for peach, apple, potato, onion, tomato, bell pepper, broccoli, and seven types of cucurbits. The coefficient of variation for estimation of an amino acid level generally fell in the range of 5% to 7%. Because of marked variability in physiological amino acid content as a result of growing conditions, cultural practices, and inherent cultivar differences, comparisons of results with literature values were not possible.展开更多
In 2010, a foliar and stem-lesion disease that produced moderate to severe defoliation of watermelon was observed in the southern Great Plains. The disease was ultimately determined to be caused by Myrothecium roridum...In 2010, a foliar and stem-lesion disease that produced moderate to severe defoliation of watermelon was observed in the southern Great Plains. The disease was ultimately determined to be caused by Myrothecium roridum. The objective of this study was to compare the susceptibility of the vegetation and fruit of a broad range of commercially important cucurbits to three isolates obtained from these foliar lesions on watermelon. In greenhouse foliar inoculation experiments, cantaloupe, honeydew, cucumber, squash, and watermelon were susceptible to the fungus with cantaloupe and honeydew being the most susceptible and watermelon the most resistant. Furthermore, greenhouse inoculations supported earlier field observations as differential resistance was exhibited among the watermelon cultivars as well as the cucurbit types. All tested cucurbit fruit exhibited interior lesions when inoculated sub-epidermally with M. roridum isolates. However, natural infection of watermelon and pumpkin fruit has never been reported.展开更多
文摘Many of the extraction and amino acid analysis methodologies currently employed do not provide complete analysis of all the physiological amino acids and biogenic amines. Extraction procedures frequently employ dilute acid which partially converts gln and asn to glu and asp. A commonly used pre-column derivatizing agent, o-phthalaldehyde, does not react with the imino acids, pro and hydroxypro. The purpose of this investigation was to integrate extraction and analysis procedures into a reliable method for measuring the complete physiological amino acid profiles of fruit and vegetables using HPLC instrumentation commonly available to most laboratories. Water extraction of ground, frozen-thawed tissues effected complete recovery of the physiological amino acids as demonstrated by spiking experiments and tissue combination experiments. HPLC of dabsyl derivatives of the free amino acids allowed their quantification in a selection of fruit and vegetables. Physiological amino acid levels were determined for peach, apple, potato, onion, tomato, bell pepper, broccoli, and seven types of cucurbits. The coefficient of variation for estimation of an amino acid level generally fell in the range of 5% to 7%. Because of marked variability in physiological amino acid content as a result of growing conditions, cultural practices, and inherent cultivar differences, comparisons of results with literature values were not possible.
文摘In 2010, a foliar and stem-lesion disease that produced moderate to severe defoliation of watermelon was observed in the southern Great Plains. The disease was ultimately determined to be caused by Myrothecium roridum. The objective of this study was to compare the susceptibility of the vegetation and fruit of a broad range of commercially important cucurbits to three isolates obtained from these foliar lesions on watermelon. In greenhouse foliar inoculation experiments, cantaloupe, honeydew, cucumber, squash, and watermelon were susceptible to the fungus with cantaloupe and honeydew being the most susceptible and watermelon the most resistant. Furthermore, greenhouse inoculations supported earlier field observations as differential resistance was exhibited among the watermelon cultivars as well as the cucurbit types. All tested cucurbit fruit exhibited interior lesions when inoculated sub-epidermally with M. roridum isolates. However, natural infection of watermelon and pumpkin fruit has never been reported.
