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. 相似文献
Blood glycosylated hemoglobin (GHb) concentration was quantified in 84 healthy cats, 9 cats with stress-induced hyperglycemia, 37 cats with newly diagnosed diabetes mellitus, and 122 diabetic cats treated with insulin or glipizide. Diabetic control was classified as good or poor in insulin-treated or glipizide-treated cats based on review of history, physical examination findings, changes in body weight, and measurement of blood glucose concentrations. Blood GHb concentration was determined using an affinity chromatography assay. Mean blood GHb concentration was similar for healthy normoglycemic cats and cats with transient, stress-induced hyperglycemia, but was significantly (P < .001) higher in untreated diabetic cats when compared with healthy normoglycemic cats. Mean blood GHb concentration was significantly (P < .001) higher in 84 cats with poorly controlled diabetes mellitus when compared with 38 cats in which the disease was well controlled. Mean blood GHb concentration decreased significantly (P < .01) in 6 cats with untreated diabetes mellitus after insulin and dietary treatment. A similar significant (P < .01) decrease in mean blood GHb concentration occurred in 7 cats with poorly controlled diabetes mellitus after diabetic control was improved by an increase in insulin dosage from 1.1 ± 0.9 to 1.4 ± 0.6 U/kg/ 24 h and by feeding a diet containing increased fiber content and in 6 cats with transient diabetes mellitus 8.2 ± 0.6 weeks after discontinuing insulin treatment. There was a significant (P< .01) stress-induced increase in mean fasting blood glucose concentration and mean blood glucose concentration for 12 hours after administration of insulin or glipizide but no change in mean blood GHb concentration in 5 docile diabetic cats 12.2 ± 0.4 weeks after the cats became fractious as a result of frequent hospitalizations and blood samplings. Results of this study suggest that evaluation of blood GHb concentration may be a clinically useful tool for monitoring glycemic control of diabetes in cats. 相似文献
A single mummified fetus was removed from the uterus of a 23-year-old mare that had been bred approximately 30 months previously. The mare had received supplemental progestin therapy for approximately 150 days after ovulation. This case represents the longest recorded occurrence of fetal mummification in the mare. Progestion administration may have contributed to the initial retention of the fetus in the uterus. 相似文献
The productivity of Leucaena leucocephala and a superior L. pulverulenta family were examined over a 3-year period at spacings (1.5 m×1.5 m and 1.5×3.0 m) chosen to compare two mechanical weeding operations. Leucaena pulverulenta was examined since faster-growing families of this cold-hardy, low-mimosine leucaena species were recently identified. There was no significant difference in yields between the species (P = 0.9060) but there was a significant difference between spacings (P = 0.0491). There was no significant spacing×species, species×year or spacing×year interaction. The annual growth rates for the first, second, and third seasons' growth for L. leucocephala were 3.73, 10.11 and 6.00 t ha−1 at the close spacing and 3.03, 7.14 and 5.04 for the wider spacing. The annual growth-rates for the first, second and third seasons' growth for L. pulverulenta were 2.03, 8.35 and 8.31 t ha−1 at the close spacing and 1.25, 9.38 and 5.29 at the wider spacing. Despite the fact that L. leucocephala froze to the ground in the first and second winter when L. pulverulenta was nearly undamaged, the L. leucocephala coppice resprout was greater than the second year's growth for L. pulverulenta. 相似文献
Dehydrins are proteins associated with conditions affecting the water status of plant cells, such as drought, salinity, freezing and seed maturation. Although the function of dehydrins remains unknown, it is hypothesized that they stabilize membranes and macromolecules during cellular dehydration. Red-osier dogwood (Cornus sericea L.), an extremely freeze-tolerant woody plant, accumulates dehydrin-like proteins during cold acclimation and the presence of these proteins is correlated with increased freeze tolerance (Karlson 2001, Sarnighausen et al. 2002, Karlson et al. 2003). Our objective was to determine the location of dehydrins in cold-acclimated C. sericea stems in an effort to provide insight into their potential role in the freeze tolerance of this extremely cold hardy species. Abundant labeling was observed in the nucleus and cytoplasm of cold-acclimated C. sericea stem cells. In addition, labeling was observed in association with plasmodesmata of cold-acclimated vascular cambium cells. The unique association of dehydrin-like proteins with plasmodesmata has not been reported previously. 相似文献
Reporting carbon (C) stocks in tree biomass (above- and belowground) to the United Nations Framework Convention on Climate
Change (UNFCCC) should be transparent and verifiable. The development of nationally specific data is considered ‘good practice’
to assist in meeting these reporting requirements. From this study, biomass functions were developed for estimating above-
and belowground C stock in a 19-year-old stand of Sitka spruce (Picea sitchensis (Bong) Carr.). Our estimates were then tested against current default values used for reporting in Ireland and literature
equations. Ten trees were destructively sampled to develop aboveground and tree component biomass equations. The roots were
excavated and a root:shoot (R) ratio developed to estimate belowground biomass. Application of the total aboveground biomass function yielded a C stock
estimate for the stand of 74 tonnes C ha−1, with an uncertainty of 7%. The R ratio was determined to be 0.23, with an uncertainty of 10%. The C stock estimate of the belowground biomass component was
then calculated to be 17 tonnes C ha−1, with an uncertainty of 12%. The equivalent C stock estimate from the biomass expansion factor (BEF) method, applying Ireland’s
currently reported default values for BEF (inclusive of belowground biomass), wood density and C concentration and methods
for estimating volume, was found to be 60 tonnes C ha−1, with an uncertainty of 26%. We found that volume tables, currently used for determining merchantable timber volume in Irish
forestry conditions, underestimated volume since they did not extend to the yield of the forest under investigation. Mean
stock values for belowground biomass compared well with that generated using published models. 相似文献
The potential of bacteriophage therapy to control bacterial disease in farmed fish was tested using, as an example, furunculosis of Atlantic salmon, caused by Aeromonas salmonicida subsp. salmonicida.
In vivo testing with Atlantic salmon and rainbow trout (Oncorhynchus mykiss Walbaum) showed no adverse effects, with bacteriophage generally cleared within 96 h of administration by either intraperitoneal (i.p.) injection or oral in-feed.
Juvenile Atlantic salmon were administered a combination of bacteriophage O, R and B (1.9 × 108 pfu fish− 1) by i.p. injection, after they had been challenged with A. salmonicida subsp. salmonicida 78027, also by i.p. injection. The fish that were injected with bacteriophage immediately after challenge died at a significantly slower rate then those that were either not treated with bacteriophage, or treated 24 h post-challenge. However, the end result (100% mortality) was not affected.
In further experiments the effects of oral (1.88 × 105 pfu g− 1 fish− 1 daily for 30 days), bath (1.04 × 105 ml− 1 daily for 30 days) and i.p. (6.25 × 107 pfu fish− 1) phage treatment to control furunculosis in experimentally infected Atlantic salmon were compared with antibiotherapy (treatment with 10 mg kg− 1 bw− 1 day− 1 oxolinic acid for 10 days), using an indirect cohabitation challenge. No protection was offered by any of the bacteriophage treatments, compared to the positive challenge group, although significant protection was offered by the oxolinic acid treatment. Analysis of samples taken from the trials demonstrated that bacteriophage were correctly administered to the fish and, on occasion, were isolated from fish that had succumbed to furunculosis. It was also shown that bacteriophage resistant A. salmonicida subsp. salmonicida isolates could be recovered from mortalities in all the treatment groups.
The results suggest that, although there were no safety problems associated with the approach, furunculosis in Atlantic salmon is not readily controllable by application of bacteriophage. 相似文献
The amount of short-wave solar radiation willingly tolerated by lactating Holstein cows on pasture was determined in an equatorial semi-arid environment. The study was carried out on a dairy farm located in Limoeiro do Norte, CE, northeastern Brazil. The observed behaviours were as follows: grazing, under the sun, under the shade, standing, lying, ruminating, idling and wallowing in the water. The behaviours were recorded using instantaneous scan sampling at regular intervals of 15 min from 0600 to 1800 hours over 5 days. On all sampling days, the meteorological variables, including local short-wave solar radiation (RS-W, W m?2), were recorded. The RS-W data were divided into five levels. The sun exposure was more frequent under low (100 %) and moderately low (97 %) levels, when RS-W remained below 500 W m?2. The grazing was more intense under low (100 %) and moderately low (93 %) levels. Above 500 W m?2, the grazing time significantly decreased (11 %). The cows avoided grazing under high (0 %) and very high (0 %) levels, when RS-W exceeded 700 W m?2. The ruminating behaviour was more frequent under high (33 %) and very high (37 %) levels, in which the highest averages of RS-W were recorded (815 and 958 W m?2, respectively). The standing posture was more frequent under low (100 %) and moderately low (97 %) levels. Therefore, the critical RS-W level that motivates cows to stop grazing and seek shade was in the interval between 500 and 700 W m?2. 相似文献