Responses of citrus fine roots to localized soil drying: a comparison of seedlings with adult fruiting trees

We studied the responses of citrus (Citrus volkameriana Tan. & Pasq.) roots to 15 weeks of soil drying. A comparison was made between the fine roots of 1-year-old seedling root systems (seedling) and the fine roots of woody laterals of 6-year-old grafted trees (adult). Each seedling and woody lateral root system was established in a pair of vertically separated and independently irrigated soil compartments located in field root chambers excavated adjacent to the trees to which the woody laterals were attached. Root + soil respiration and fine root survival of seedlings and adults were similar for the first 5 weeks. However, eight weeks after termination of irrigation to the upper soil compartments, mortality of fine roots was high in adults but not seedlings. Fine roots of adults exposed to dry soil for 5, 8 and 15 weeks exhibited 2, 26 and 33% mortality, respectively, whereas the corresponding values for fine roots of seedlings were 2, 6 and 8%. Although root + soil respiration rates of adults and seedlings were similar before the soil drying treatment, rates for adults were only 25% of those for seedlings after 15 weeks of soil drying. We conclude that, although fine roots of adults and seedlings are similar in form, they respond differently to soil drying.     

Denaturation and aggregation of myosin from two bovine muscle types

The thermal behaviors of myosin from bovine vastus intermedius (VI, predominantly red muscle) and semimembranosus (SM, predominantly white muscle) at pH 6.05 (ultimate pH of VI muscle) and 5.50 (ultimate pH of SM muscle) were compared. Differential scanning microcalorimetry and turbidity measurements were used to monitor changes in myosin during heating from 25 to 80 degrees C at 1 degrees C/min. VI and SM myosin heavy chain isoforms were identified on gradient SDS-PAGE. Endotherms of VI myosin at pH 6.05 had three transition temperatures (T(m)) of 45, 53, and 57 degrees C, whereas at pH 5.50 two transitions were observed at 42 and 59 degrees C. SM myosin had two T(m) values of 46 and 58 degrees C at pH 6.05 and T(m) values of 43 and 62 degrees C at pH 5.5. SM myosin at its ultimate pH was less heat stable than VI myosin at its ultimate pH; however, when SM and VI myosin were compared at the same pH, VI myosin was less stable.     

Purple carrot (Daucus carota L.) polyacetylenes decrease lipopolysaccharide-induced expression of inflammatory proteins in macrophage and endothelial cells

Carrots ( Daucus carota L.) contain phytochemicals including carotenoids, phenolics, polyacetylenes, isocoumarins, and sesquiterpenes. Purple carrots also contain anthocyanins. The anti-inflammatory activity of extracts and phytochemicals from purple carrots was investigated by determining attenuation of the response to lipopolysaccharide (LPS). A bioactive chromatographic fraction (Sephadex LH-20) reduced LPS inflammatory response. There was a dose-dependent reduction in nitric oxide production and mRNA of pro-inflammatory cytokines (IL-6, IL-1beta, TNF-alpha) and iNOS in macrophage cells. Protein secretions of IL-6 and TNF-alpha were reduced 77 and 66% in porcine aortic endothelial cells treated with 6.6 and 13.3 microg/mL of the LH-20 fraction, respectively. Preparative liquid chromatography resulted in a bioactive subfraction enriched in the polyacetylene compounds falcarindiol, falcarindiol 3-acetate, and falcarinol. The polyacetylenes were isolated and reduced nitric oxide production in macrophage cells by as much as 65% without cytotoxicity. These results suggest that polyacetylenes, not anthocyanins, in purple carrots are responsible for anti-inflammatory bioactivity.     

Volatile constituents of fermented sugar baits and their attraction to lepidopteran species

The volatile compounds emanating from four fermented sugar baits, palm sugar, golden cane syrup, port wine, and molasses, were isolated by headspace sampling and analyzed by gas chromatography-mass spectrometry. Three classes of compounds including esters, alcohols, and aromatic compounds were identified in the headspace of the four fermented sugar baits. There was a high degree of qualitative similarity between the headspace contents of the four fermented sugar baits, although quantitatively they varied considerably. Ethyl acetate, 3-methylbutanol, ethyl hexanoate, 2-phenylethanol, ethyl octanoate, ethyl (E)-4-decenoate, ethyl decanoate, and ethyl dodecanoate were the major compounds identified in the headspace of the four fermented sugar baits. The efficacy of the four fermented sugar baits was investigated in field trapping experiments. Fermented palm sugar and golden cane syrup were superior in attracting significant numbers of moths as compared to port wine and molasses. Fermented molasses was the least attractive among the four baits. Over 90% of the insects caught were noctuids with Graphania mutans and Tmetolophota spp. being the main noctuids captured (over 55%) in the four fermented sugar baits. Male and female G. mutans were equally attracted to the four sugar baits. A number of tortricid species were also trapped.     

Specificity of codling moth (Lepidoptera: Tortricidae) for the host plant kairomone, ethyl (2E,4Z)-2,4-decadienoate: field bioassays with pome fruit volatiles, analogue, and isomeric compounds

Codling moth, Cydia pomonella (L.), is a severe pest of apples, pears, and walnuts worldwide, and new approaches for precise monitoring and management would be beneficial. Ninety-two pome fruit volatiles were formulated in 23 distinct blends, of which a single 4-component blend of 10-carbon esters showed the only significant attraction of moths in field bioassays conducted in both walnut and apple orchards. A single constituent of this blend, ethyl (2E,4Z)-2,4-decadienoate--the "pear ester", was the major contributing attractant. The pear ester attracted both male and female moths in combined numbers that were comparable to the attractiveness of conspecific sex pheromone. Structure-activity tests were conducted in a series of orchard trials to determine the specificity of attraction of codling moths to the pear ester kairomone. No analogue 10-carbon alcohols, aldehydes, acetates, or other esters elicited significant moth capture responses. Tests with various analogue esters with alcohol chain length moiety substitutions of the (2E,4Z)-2,4-decadienoic acid elicited differential capture responses, with the ethyl exceeding the propyl, methyl, butyl, and hexyl analogues. The (E,Z) geometric isomers of this series of (2E,4Z)-2,4-decadienoic acid esters far exceeded the attractiveness of the (E,E) isomers. The pear ester is a potent attractant of both males and females, and codling moths are highly discriminating and specific in their structure-activity-based attraction to this pear-derived kairomone. These specificity attributes should allow this host plant kairomone to contribute to new abilities for female monitoring and the potential of development of novel and highly selective control practices that should decrease the current dependence on the use of broad-spectrum insecticides.     

Predicting the potential of engulfment using an on-farm grain storage hazard assessment tool

The goal of this research was to address the problem of engulfment in flowing grain in on-farm metal grain storage bins. This was accomplished using a systems approach to identify contributing factors to engulfment, which were then used to develop a 28-question Farm Grain Hazard Assessment Tool (FGHAT). A numerically weighted high- and low-risk response accompanied each question, the sum of which resulted in a potential-risk-of-engulfment score for a given on-farm grain handling and storage system. The assessment tool was pilot tested on a sample of 47 farms. The difference between the mean scores of farms with a history of engulfment (n = 14) and the mean scores of farms with no prior reported engulfment incident (n = 33) was significant (p < or = 0.001). This finding suggests that it is possible, using the hazard assessment tool, to predict the increased likelihood of an engulfment in a specific on-farm grain storage and handling system. It was also found that the management of grain during storage and an individual's perception of risk and willingness to avoid flowing grain hazards had the most significant impact on reducing the potential for an engulfment. In contrast, a history of grain plugging problems was not found to make a considerable difference in scores between the two groups of farms. The presence of stirring devices in bins, accommodation for lockout devices on electrical controls, and using grain storage bins smaller than 20, 000 bu capacity also had little impact on the difference in scores. Based upon the level of significance of each of the 28 questions'ability to predict an increased risk of engulfment, it was concluded that a valid response could be obtained with as few as eight questions. Recommendations concerning continued study and application of the tool were formulated, including the effectiveness of the tool in changing the farmers' behavior, and the findings also contributed to the revision of a potential engineering standard for on-farm grain storage structures.     

Pre-extraction preparation (fresh, frozen, freeze-dried, or acetone powdered) and long-term storage of fruit and vegetable tissues: effects on antioxidant enzyme activity

Activities of the antioxidant enzymes ascorbate peroxidase, catalase, dehydroascorbate reductase, glutathione reductase, guaiacol peroxidase, monodehydroascorbate reductase, and superoxide dismutase were assayed in honeydew (Cucumis melo L.) fruit and spinach (Spinacia oleracea L.) leaves either as fresh, frozen to -80 degrees C, frozen in liquid nitrogen, freeze-dried, or acetone powder, representing the various ways tissues are treated prior to enzyme extraction. Treated tissues were analyzed following treatment or stored for up to 8 weeks at -80 degrees C. Enzyme activities in fruit frozen with or without liquid nitrogen and leaves frozen with or without liquid nitrogen or freeze-dried were equal to those of fresh tissue. Enzyme activities in freeze-dried or acetone-powdered fruit and leaves and in acetone-powdered tissues were significantly higher or lower than those in fresh tissue. Enzyme activities in both tissues frozen with or without liquid nitrogen and stored for 8 weeks at -80 degrees C changed little; those in freeze-dried and acetone-powdered tissues, however, significantly increased/decreased over the same period. Fresh tissue should be used in antioxidant enzyme assays, but if storage is necessary, tissues should be placed directly into a -80 degrees C freezer.     

Yerba Maté (Ilex paraguariensis) aqueous extract decreases intestinal SGLT1 gene expression but does not affect other biochemical parameters in alloxan-diabetic Wistar rats

Yerba maté (Ilex paraguariensis) is rich in polyphenols, especially chlorogenic acids. Evidence suggests that dietary polyphenols could play a role in glucose absorption and metabolism. The aim of this study was to evaluate the antidiabetic properties of yerba maté extract in alloxan-induced diabetic Wistar rats. Animals (n = 41) were divided in four groups: nondiabetic control (NDC, n = 10), nondiabetic yerba maté (NDY, n = 10), diabetic control (DC, n = 11), and diabetic yerba maté (DY, n = 10). The intervention consisted in the administration of yerba maté extract in a 1 g extract/kg body weight dose for 28 days; controls received saline solution only. There were no significant differences in serum glucose, insulin, and hepatic glucose-6-phosphatase activity between the groups that ingested yerba maté extract (NDY and DY) and the controls (NDC and DC). However, the intestinal SGLT1 gene expression was significantly lower in animals that received yerba maté both in upper (p = 0.007) and middle (p < 0.001) small intestine. These results indicate that bioactive compounds present in yerba maté might be capable of interfering in glucose absorption, by decreasing SGLT1 expression.     

Volatile emissions of navel oranges as predictors of freeze damage

Volatile emissions of navel orange (Citrus sinensis L. Osbeck cv. Washington) fruit were evaluated as a means for predicting and gauging freeze damage. The fruits were subjected to -5 or -7 degrees C treatments in a laboratory freezer for various time periods of 2-9.5 h and stored at 23 degrees C for 1, 2, or 7 days, after which time the emission of volatiles from the fruit was measured. Following the final day of volatile measurements the fruits were stored at 5 degrees C for an additional 2-3 weeks and then evaluated for fruit quality characteristics. Peel injury in the form of brown lesions, drying of the juice vesicles, a decline in acidity, and a loss of flavor were observed to occur as a result of freezing. Corresponding to the loss in fruit quality were large increases in the emissions of ethanol, ethyl butanoate, methyl hexanoate, and ethyl octanoate. With the exception of methyl hexanoate, for which volatile emissions decreased during storage for 7 days at 23 degrees C, all of the other volatiles were relatively unchanged in amount by storage. Treatment at -7 degrees C caused greater injury, quality loss, and more volatile emanation than did freezing at -5 degrees C. The measurement of volatile emissions appears to be a useful approach to identify freeze-damaged navel oranges.