Daffodil flower delay senescence in cut Iris flowers

Visible symptoms of tepal senescence in cut Iris x hollandica (cv. Blue Magic) flowers were delayed by placing one cut daffodil flower (Narcissus pseudonarcissus, cv. Carlton) in the same vase. Addition of mucilage, exuded by daffodil stems, to the vase water had the same effect as the flowering daffodil stem. The active compound in the mucilage was identified as narciclasine (using LC/MS, GC/MS, H-1 and C-13-NMR, and comparison with an authentic sample of narciclasine). The delay of senescence, either by mucilage or purified narciclasine, was correlated with a delayed increase in protease activity, and with a considerable reduction of maximum protease activity. Narciclasine did not affect in vitro protease activity, but is known to inhibit protein synthesis at the ribosomal level. Its effects on senescence and protease activity were similar to those of cycloheximide (CHX), another inhibitor of protein synthesis, but the effective narciclasine concentration was about 100 times lower than that of CHX. It is concluded that the delay of Iris tepal senescence by daffodil stems is due to narciclasine in daffodil mucilage, which apparently inhibits the synthesis of proteins involved in senescence. (C) 2003 Elsevier Ltd. All rights reserved

Optimaal pluktijdstipbepaling pruim : deelonderzoek A&F Wageningen ism PPO Randwijk

Pruimen hebben in Nederland een goede marktwaarde die echter wordt beperkt door beperkte beschikbaarheid en bewaarbaarheid. Enerzijds is de aanvoer kort in het jaar en kent dan een overschot in aanvoer, anderzijds heeft men na de oogst een prachtig, maar kwetsbaar product dan ook nog kort houdbaar is. Dit project is een onderdeel van een bredere aanpak om enerzijds te komen tot spreiding in aanvoer door een afgewogen combinatie van vroege, late en rassen die er tussen in zitten. Daarnaast is het belangrijk zowel voor verkoop dat de pruim in optimale conditie bij de consument komt en dan ook nog enkele dagen houdbaar, als ook voor het optimale tijdstip van plukken voor langere bewaring. Het vaststellen van het pluktijdstip van pruim gebeurt nu vooral op ervaring en gevoel. Objectieve criteria voor vaststelling van het optimale oogstmoment zijn er nauwelijks. Bij tweekleurige rassen geeft het voortschrijden van de dekkleurvorming houvast bij de bepaling van het pluktijdstip. Bij éénkleurige rassen met een donkere kleur (donkerrood, blauwrood of blauw) is veelal al geruime tijd voor het plukmoment sprake van geheel gekleurde vruchten. Bepaling van het juiste pluktijdstip wordt daardoor nog lastiger. Er is voor dit jaar (2006) gekozen zoveel mogelijk de pruimen, middels metingen te volgen in hun ontwikkeling om een indruk te krijgen welke objectieve methoden er zouden zijn om de rijping te volgen om zo voor de toekomst betrouwbare methoden te ontwikkelen om op het juiste moment te plukken

In vivo screening of five phytochemicals/extracts and a fungal immunomodulatory protein against colibacillosis in broilers

Besides the anticoccidial drug resistance problem, increasing consumer concerns about food safety and residues have propelled the quest for alternative prevention and control strategies amongst which phytotherapy has gained appeal due to a renewed interest in natural medicine.Objective: The objective was in vivo screening of four phytochemicals/extracts and a fungal immunomodulatory protein (FIP) against an Eimeria acervulina infection in broilers.Animals and methods: Four phytochemicals/extracts (extract from Echinacea purpurea, betaine (Betain™), curcumin, carvacrol (two different doses)), and a recombinant FIP from Ganoderma lucidum cloned and expressed in Escherichia coli were investigated for their anticoccidial potential. The experiment was conducted in a battery cage trial with 54 cages of eight birds each. Broilers infected with E. acervulina (a low and high infection dose of 104 and 105 sporulated oocysts, respectively) and treated with the phytochemicals/extracts or the FIP were compared with broilers treated with the anticoccidial salinomycin sodium (Sacox®) and with an untreated uninfected and an untreated infected control group. Coccidiosis lesion scores, body weight gains and oocyst shedding were used as parameters.Results: The results showed a coccidiosis infection dose effect on the mean coccidiosis lesion scores. The phytochemicals/extracts and the FIP failed to reduce coccidiosis lesion scores and oocyst shedding, while salinomycin efficiently controlled the E. acervulina infection and enabled significantly higher body weight gains.Conclusion: In conclusion, the selected phytochemicals/extracts and the FIP did not reduce the lesions of an experimentally induced E. acervulina infection

Humidity control during bell pepper storage, using a hollow fiber membrane contractor system

Green bell peppers (Capsicum annuum cv. Cardio) were stored in open crates at 5 degreesC, using a novel system for maintenance of relative humidity (RH). A hollow fiber membrane contactor allowed adequate transfer of water vapor between the air in the storage room and a liquid desiccant. The membrane was made of polyetherimide (PEI), coated on the inside with a thin non-porous silicone layer. The desiccant was a dilute aqueous glycerol solution, which was pumped through the hollow fibers at a low flow rate. Produce was placed in ventilated 5001 containers with a closed lid. During the 3 weeks of the experiment, RH could be maintained within a narrow range each day (e.g. 90.5 +/- 0.1%). RH could be changed by adjusting the glycerol concentration and/or the temperature of the desiccant. The control was a 5501 container connected to the hollow fiber membrane set up which had no glycerol solution (average RH 93%). The contactor thus removed water vapor in this set up. The quality of the bell peppers (visible peel shrivelling and fungus development), after 3 weeks of storage, was highly dependent on RH. Compared with the control container and with packaging in conventional cardboard boxes for bell peppers (average RH 86%), the contactor system reduced fungus development without increasing shrivelling. The improvement compared with cardboard boxes was presumably due to reduction of local differences in RH. Such differences were avoided in the containers where the packaging was very open (open crates, with space in between them, and only two layers of fruit) and where the airflow was rather high. In preliminary experiments with red currants and pears the contactor system also functioned well (a) at subzero temperatures, (b) when it was combined with controlled atmosphere (7.5% oxygen and 20% carbon dioxide), or (c) when it released water vapor. It is concluded that the system is promising for the large-scale storage of several fresh commodities. (C) 2004 Elsevier B.V. All rights reserved