The effect of dialkylamine compounds and related derivatives of 1-methylcyclopropene in counteracting ethylene responses in banana fruit

Compounds that can block the ethylene receptor and be applied either as a gas or as a salt by spray or dip have been prepared and tested. Cyclopropenes with a methyl group in the 1-position, on which was attached a substituted amine, were allowed to evaporate in the presence of bananas that were treated with the gas. The minimum amount of a given compound required to inhibit chlorophyll degradation in the banana peel (an indicator of protective effect of the compound against ethylene action) that was subsequently exposed to ethylene, varied considerably depending on the compound, but N,N-dipropyl-(1-cyclopropenylmethyl)amine and N,N-di-(1-cyclopropenylmethyl)amine were the most effective. The degree of response to the ethylene inhibitory effect was similar for all of the compounds tested (32–34 d). The amount of cyclopropene compound required for inhibiting ethylene action following a 24 h exposure of bananas to the salt followed by a 15 h exposure to ethylene was higher than that required by the gas form used under the same conditions for the same effect. However, time of exposure could be much longer than 24 h with the salt than with the gas. The bananas treated with the salt do not need to be in an air-tight container, but could be used in open spaces. Only the banana peel appeared to be protected against ethylene during the 24 h interval when the salt was used. The pulp ripened upon exposure to ethylene.     

Decay control and fungicide residues in citrus fruits seal-packed in a high-density polyethylene film

The effects of a new packaging method of sealing individual fruits in film of highdensity polyethylene (HDPE), on decay control and the residue levels of various fungicides applied to the fruit, were investigated with four different citrus cultivars. HDPE seal-packaging by itself reduced the decay of Marsh grapefruit but slightly enhanced the decay of Valencia orange fruit in comparison with conventionally handled fruit. Seal-packaging of individual fruit resulted in much less decay than sealing a whole carton of fruit together. The fungicides imazalil, sec-butylamine, 2-phenylphenol, benomyl and thiabendazole markedly reduced the decay of sealed fruit in all cultivars of citrus fruits tested. Residue levels in treated fruit were below the tolerances permitted. The new method of packaging had no effect on the residue levels of benomyl, 2-phenyl-phenol and thiabendazole in the fruit; neither did it affect the extent of absorption of these fungicides into the fruit. Only the volatile fungicide sec-butylamine was found at a higher level (73% higher in the packaged fruit compared with conventionally treated fruit).     

Treatment of citrus fruit with sodium o-phenylphenate foam

The treatment conditions for reducing the incidence of rot in stored citrus fruit with sodium o-phenylphenate (SOPP) foam and the possibility of improving the efficiency of the treatment were examined. Marked differences were noted among different packing houses with regard to ambient temperature temperature of the fruit surface, duration of treatment, SOPP content and pH of the solution, quantities of foam and of SOPP dispersed on the fruit, and between the o-phenylphenol (OPP) residues in fruit treated simultaneously. It should be possible to prolong the duration of treatment without increasing the OPP residues in the fruit above the tolerance limits of 10 ppm OPP in the whole fruit and without causing injury to the fruit.     

Effect of sodium 2-phenylphenate applied in wax coatings on appearance of injuries in citrus fruit

Citrus fruits were treated with wax coatings containing sodium 2-phenylphenate tetrahydrate (SOPP) and stored at 10 °C. No injuries appeared during 30 days' storage in Valencia oranges sprayed with waxes containing up to 4.75% of SOPP, or during 70 days' storage in Shamouti oranges and in grapefruit dipped in waxes containing up to 2.16% of SOPP. In Shamouti oranges and grapefruit dipped in waxes containing 3.1 to 3.88% of SOPP, injuries appeared at the beginning of storage. In non-injured fruits, the amounts of SOPP applied by waxing did not exceed 74.7 μg/cm² of the fruit surface and the 2-phenylphenol (OPP) residues in the fruits did not exceed 36.8 parts/million; in injured fruits the amounts of SOPP applied varied between 105.1 and 211.3 μg/cm² and the OPP residues between 41.5 and 123.6 parts/million. In non-injured fruit the amount of wax applied did not exceed 3.46 μl/cm²; in injured fruits the figure varied between 3.19 and 6.2 μg/cm², suggesting that the wax coating concentrates at some places on the peel, causing injuries to the fruit. In injured grapefruit 7.93 μl/cm² of wax was found on the injured part of the peel, and 3.21 μl/cm² on the non-injured part, so that 124.6 μg of SOPP/cm² corresponding to 61.6 parts/million of OPP in the fruit was applied to the fruit without causing injuries.     

Anatomical location of arterial and venous lines significantly affects motor performance in rats

Several motor‐function scales have been developed to assess neurological function in animal models of stroke, subarachnoid hemorrhage and closed head injury. We hypothesize that the location of arterial and venous catheters, even in the absence of brain injury, may impact rats' motor performance. Our study examined the effect of catheter location, rate of infection and the time required for catheter placement. We further describe an original technique of tail artery cannulation without exposure of the artery. Sixty‐one rats were anesthetized and randomly assigned to one of seven groups, including no catheter, tail artery or artery + vein catheters, or femoral artery or artery + vein catheters. A neurological severity score (NSS) was determined at 1 h, 24 h and 48 h after surgical preparation or catheter placement. NSS at 1 h after placement of unilateral and bilateral femoral catheters was higher than the NSS observed at 1 h after placement of tail arterial and venous catheters (P < 0.01). The NSS also was higher at 24 h in the bilateral femoral catheter groups as compared with the tail catheter groups (P < 0.05). There were no differences in the NSS observed between the groups that had tail catheters and the sham group at 1 h, 24 h or 48 h. Infection rate at the site of catheter placement and the time required for catheter placement was also higher in the femoral catheter groups (P < 0.001). Thus, we propose that the line location may bias a study's results and lead to deceptive interpretations of neurological assessment following rat head injury. Compared to femoral vessels, tail blood vessels are preferable locations for lines placement.     

Subatmospheric pressure storage of mango fruits

Ripening of mango fruit is markedly delayed when the pressure in the storage chamber is reduced below 100 mm Hg, and fruit storage life is thus prolonged. The prolongation of storage life is inversely related to the pressure; control fruit stored at 760 mm Hg started to ripen after 16 days in storage at 13°C, while fruit stored at 100 and 75 mm Hg after 25 and 35 days, respectively. Fruit stored at 50 mm Hg remained unripe for 35 days. No effect on ripening was recorded at pressures above 250 mm Hg, while at pressures below 50 mm Hg the fruit desiccated. All fruits stored at subatmospheric pressure ripened 3–4 days after transfer to shelf life at 25°C. However, green mango fruits of the colored cultivars like ‘Haden’ and ‘Maya’, stored at subatmospheric pressure for a prolonged period, did not develop the proper red or orange color during shelf-life, but turned pale yellow instead. Treatment with ethylene upon removal from storage slightly improved color development in these fruits.