Chemicals used for treatment of water intended for human consumption. High-calcium lime

2008 ◽  
Author(s):  
Kerry R. Everett

Abstract The avocado (Persea americana Mill.) is from an ancient plant lineage, the Lauraceae. Although evidence for human consumption dates back 15,000 years, commercialisation has occurred only over the last 150 years. The most commonly traded variety was first the green-skin 'Fuerte' (green as it ripens), and more recently 'Hass', on which skin darkens when ripe. Production has been increasing worldwide, and currently about 64 countries produce avocados. The range of climates is from arid to very high rainfall and from tropical to temperate. The minimum daily temperatures are above 5°C in all avocado-growing regions because of frost sensitivity. Apart from avocado sunblotch viroid (ASBVd), most avocado fruit diseases are caused by fungi. Some fungi cause visible symptoms resulting in unmarketable fruit, and other infections in the orchard are symptomless. These symptomless infections express as rots after harvest during cold storage, transport and ripening. Most post-harvest pathogens infect through both the body of the fruit and the stem-end wound, while a few infect only through the stem-end wound. The geographic distribution of these fungi varies possibly because of differences in environmental requirements and effective quarantine measures during trade. Fungal rots can be reduced by the application of fungicides in the orchard, removing inoculum residing in dead branches and mummified fruit in the canopy, ensuring high-calcium levels in the fruit flesh are maintained, careful post-harvest handling and selling fruit as soon after harvest as possible. Some post-harvest fungicides can be effective.


Author(s):  
Martin Poenie ◽  
Akwasi Minta ◽  
Charles Vorndran

The use of fura-2 as an intracellular calcium indicator is complicated by problems of rapid dye leakage and intracellular compartmentalization which is due to a probenecid sensitive anion transporter. In addition there is increasing evidence for localized microdomains of high calcium signals which may not be faithfully reported by fura-2.We have developed a new family of fura-2 analogs aimed at addressing some of these problems. These new indicators are based on a modified bapta which can be readily derivatized to produce fura-2 analogs with a variety of new properties. The modifications do not affect the chromophore and have little impact on the spectral and metal binding properties of the indicator. One of these new derivatives known as FPE3 is a zwitterionic analog of fura-2 that can be loaded into cells as an acetoxymethyl ester and whose retention in cells is much improved. The improved retention of FPE3 is important for both cuvettebased measurements of cell suspensions and for calcium imaging.


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