Effect of carotenoids and background colour on the skin pigmentation of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)     

Ben J Doolan  Geoff L Allan  Mark A Booth  Paul L Jones 《Aquaculture Research》2008,39(13):1423-1433

Three 2‐factor experiments were conducted to determine the effects of background colour and synthetic carotenoids on the skin colour of Australian snapper Pagrus auratus. Initially, we evaluated the effects on skin colour of supplementing diets for 50 days with 60 mg kg^?1 of either astaxanthin (LP; Lucantin^® Pink), canthaxanthin (LR; Lucantin^® Red), apocarotenoic acid ethyl ester (LY; Lucantin^® Yellow), selected combinations of the above or no carotenoids and holding snapper (mean weight=88 g) in either white or black cages. In a second experiment, all snapper (mean weight=142 g) from Experiment 1 were transferred from black to white, or white to white cages to measure the short‐term effects of cage colour on skin L^*, a^* and b^* colour values. Skin colour was measured after 7 and 14 days, and total carotenoid concentrations were determined after 14 days. Cage colour was the dominant factor affecting the skin lightness of snapper with fish from white cages much lighter than fish from black cages. Diets containing astaxanthin conferred greatest skin pigmentation and there were no differences in redness (a^*) and yellowness (b^*) values between snapper fed 30 or 60 mg astaxanthin kg^?1. Snapper fed astaxanthin in white cages displayed greater skin yellowness than those in black cages. Transferring snapper from black to white cages increased skin lightness but was not as effective as growing snapper in white cages for the entire duration. Snapper fed astaxanthin diets and transferred from black to white cages were less yellow than those transferred from white to white cages despite the improvement in skin lightness (L^*), and the total carotenoid concentration of the skin of fish fed astaxanthin diets was lower in white cages. Diets containing canthaxanthin led to a low level of deposition in the skin while apocarotenoic acid ethyl ester did not alter total skin carotenoid content or skin colour values in snapper. In a third experiment, we examined the effects of dietary astaxanthin (diets had 60 mg astaxanthin kg^?1 or no added carotenoids) and cage colour (black, white, red or blue) on skin colour of snapper (mean weight=88 g) after 50 days. Snapper fed the astaxanthin diet were more yellow when held in red or white cages compared with fish held in black or blue cages despite similar feed intake and growth. The skin lightness (L^* values) was correlated with cage L^* values, with the lightest fish obtained from white cages. The results of this study suggest that snapper should be fed 30 mg astaxanthin kg^?1 in white cages for 50 days to increase lightness and the red colouration prized in Australian markets.  相似文献   

Recovery responses of soil surface Collembola after spatial and temporal changes in long-term regimes of pesticide use     

Geoff K. Frampton 《Pedobiologia》2000,44(3-4)

Counts of several Collembola species in a rotation of grass and wheat cropping were consistently lower under a conventional regime of pesticide use than under a reduced-input regime. During a six-year period (1991–1996), counts of Entomobrya nicoleti remained at or close to zero under the conventional regime. This raised the question of how long recovery would take if conventional pesticide inputs ceased. To answer this question, and confirm effects of the pesticide regimes on patchily distributed species, the two pesticide regimes were reversed spatially: from 1997 to 1999 the area formerly under conventional inputs subsequently received the reduced-input regime and vice versa. This paper presents results up to summer 1998 to show the effect on collembolan counts of reversing the pesticide regimes. Responses varied among species: after conversion of the conventional regime to reduced inputs, counts of E. nicoleti remained at or close to zero whereas counts of Isotoma viridis were the highest recorded during the study. Data from a rotation of cereals and break crops show that reversal of treatments can aid interpretation of pesticide effects for species with a patchy temporal distribution; treatment reversal improved confidence in the interpretation of pesticide effects for species of Collembola which were not present during the pre-treatment sampling phase of a long-term study.  相似文献   

Comparison of trifluralin,oryzalin, pronamide,propham, and colchicine treatments on microtubules     

Paul G. Bartels  James L. Hilton 《Pesticide biochemistry and physiology》1973,3(4):462-472

The mode of action of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), oryzalin (3,5-dinitro-N⁴,N⁴-dipropylsulfanilamide), pronamide(N-(1,1-dimethylpropynyl) 3,5-dichlorobenzamide), and propham (isopropyl carbanilate) on purified microtubules from pig brains and on the ultrastructure of wheat (Triticum aestivum L. “Mediterranean,” C. I. 5303) and corn (Zea mays L. “yellow dent, U. S. 13”) roots was compared with that known for colchicine. Colchicine disrupts the in vivo cortical and spindle microtubules of root cells. Like colchicine, the herbicides trifluralin, oryzalin, and pronamide caused the loss of both cortical and spindle microtubules of root cells. The rate of microtubule disappearance depended on the type of herbicide and length of exposure of roots to the herbicide. Unlike colchicine, cortical microtubules were present in propham-treated roots but they were disoriented within the cell.In vitro polymerization studies with pig brain microtubules (Sus scrofa) showed that the herbicides failed to inhibit the assembly of purified microtubular protein into microtubules and that radioactively labeled herbicides did not bind to the microtubular protein. Colchicine inhibited the polymerization of microtubular protein and readily bound to the microtubular subunits. These results indicate that the mode of action of the herbicides is not similar to that of colchicine and that the loss of microtubules from root tip cells treated with trifluralin, oryzalin, and pronamide may be caused by these herbicides interfering with synthesis of microtubular protein or metabolism of endoplasmic reticulum membranes involved in microtubule assembly. The mode of action of propham appears to be on the microtubular organizing centers rather than on microtubules per se.  相似文献   

Black dot (Colletotrichum coccodes): an increasingly important disease of potato     

A. K. Lees †  A. J. Hilton 《Plant pathology》2003,52(1):3-12

In recent years black dot ( Colletotrichum coccodes ) has become an economically important disease problem in potato ( Solanum tuberosum ). It is characterized by silvery lesions on the tuber surface which result in a deterioration in skin quality. In addition to causing tuber blemish symptoms, C. coccodes also causes symptoms on stems and foliage, resulting in crop losses in some countries, and is implicated as a factor in the potato early dying disease complex. In the past, the incidence and severity of black dot might have been underestimated, as tuber symptoms were often mistaken for silver scurf ( Helminthosporium solani ). Inoculum of C. coccodes can be both seed tuber- and soilborne, and disease control is difficult as there are few chemical control methods and little resistance in commercial cultivars. Cultural control options offer the only potential means to control this disease at present. Current developments in rapid and specific PCR-based detection methods are being used to address epidemiological questions.  相似文献   

Mandibular salivary gland aspirate from a dog     

Duncan RB  Feldman BF  Saunders GK  Prater R  Troy GC 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1999,28(3):97-99

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Carbohydrates in the nutrition of the dog          下载免费PDF全文

Hilton J 《The Canadian veterinary journal. La revue veterinaire canadienne》1990,31(2):128-129

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Evaluation of four topical preparations for the treatment of cannon hyperkeratosis in a horse     

Hugo Hilton  Verena K. Affolter  Stephen D. White 《Veterinary dermatology》2008,19(6):385-390

The response to treatment with four topical preparations was evaluated in an 11‐year‐old Morgan horse mare with histologically confirmed quadrilateral cannon hyperkeratosis. Each limb was treated for 30 days with 0.1% tacrolimus ointment, 0.1% adapalene gel, 0.2% phytosphingosine spray or a water‐based emollient. Response to treatment was evaluated both histologically and visually. A water‐based emollient and 0.1% tacrolimus ointment produced encouraging clinical responses. Pre‐treatment histopathology identified marked, mostly compact, hyperkeratosis and follicular hyperkeratosis, most prominent in the infundibular area. Following treatment, histopathology identified a mild reduction in follicular keratin production and stratum corneum thickness.  相似文献   

Re‐Regulation in the Post‐WTO Period? A Case Study of Vietnam's Food Retailing Sector     

Hai T. H. Nguyen  Geoff Deverteuil  Neil Wrigley  Kanchana N. Ruwanpura 《Growth and change》2014,45(2):377-396

Academic interest on domestic regulatory (and re‐regulatory) impacts of retail foreign direct investment remains surprisingly under‐researched, despite high‐profile campaigns, particularly in Southeast Asia, to rein in the expansion of retail transnational corporations. This paper focuses on the trends of re‐regulation of foreign retailers, particularly in the food sector, in Vietnam before and after the accession to the World Trade Organization (WTO) in 2007. The findings reveal a complex layering of regulation, some of it a holdover from the pre‐2007 period and some of it occurring since WTO accession, in the form of the controversial Economic Needs Test.  相似文献   

The degradation rate of thiamethoxam in European field studies          下载免费PDF全文

Martin J Hilton  Tim D Jarvis  Dean C Ricketts 《Pest management science》2016,72(2):388-397

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Photosynthetic response to green crown pruning in young plantation-grown Eucalyptus pilularis and E. cloeziana     

Philip J. Alcorn  Jürgen Bauhus  Dane S. Thomas  Ryde N. James  R. Geoff B. Smith  Adrienne B. Nicotra 《Forest Ecology and Management》2008,255(11):3827-3838

The loss of foliage through pruning of live branches may reduce tree growth or it may be compensated by photosynthetic up-regulation of the remaining crown. Here, the changes in light-saturated photosynthesis following pruning to remove 50% of green crown length were examined in 4-year-old Eucalyptus pilularis Sm. and Eucalyptus cloeziana F. Muell. trees. The objectives of the study were to: (1) compare leaf-level physiological (light-saturated photosynthesis (A_max), stomatal conductance (g), transpiration (T), dark respiration (R_d), quantum yield (Φ), light compensation point (Γ), water-use efficiency (WUE), nitrogen-use efficiency (NUE)) traits in species with contrasting crown dynamics and structure, (2) examine the effect of crown position on these traits, and (3) examine the effect of pruning on A_max, g, T, WUE, NUE, leaf N and P concentrations and specific leaf area (SLA). Prior to pruning there were no differences in R_d, Γ and Φ between E. pilularis and E. cloeziana but differences in A_max, T, g, leaf N, leaf P, WUE, NUE and SLA. Whereas the rate of physiological processes (A_max, T, and g) and leaf N and P concentrations increased with crown height, R_d, Γ, Φ and SLA declined along this vertical gradient, except in the upper crown of E. cloeziana where A_max, T and g were not different to the lower crown. No up-regulation of photosynthesis or changes in leaf physiology occurred between 6 and 13 months after pruning in either species. The results provide an important basis for modelling pruning effects in process-based tree growth models.  相似文献