Biochemical changes associated with ripening of apples     

A. C. Hulme  M. J. C. Rhodes  L. S. C. Wooltorton  T. Galliard 《Plant foods for human nutrition (Dordrecht, Netherlands)》1969,19(1-3):1-18

The respiration climacteric and ripening in apples are described. It is suggested that the distinction between climacteric and non-climacteric fruit is more apparent than real. It is shown for apples that there is a sequence of changes in enzyme activity over the climacteric, initiated by an increased production of ethylene. Increased respiration is followed by a peak in incorporation of amino acid into protein followed, at the climacteric peak, by a large increase in a system which will decarboxylate malate when added to pieces of peel taken from the fruit. The same sequential development of enzymic processes takes place in disks of apple peel tissue taken from apples in the pre-climacteric state and aged for 24 hours.

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Zusammenfassung Es werden das Atmungsklimakterium und die Reifung bei Äpfeln beschrieben. Es wird vermutet, dass die Unterscheidung zwischen klimakterischen und nicht-klimakterischen Früchten mehr scheinbar als echt ist. Für Äpfel wird gezeigt, dass es eine Stufenfolge von Veränderungen in der Enzymaktivität, ausgelöst durch eine verstärkte Bildung von Äthylen, während des Klimakteriums gibt. Auf die Zunahme der Atmung folgt ein Gipfelpunkt des Einbaues von Aminosäuren in Proteine, gefolgt, bei dem Gipfelpunkt des Klimakteriums, von einem starken Anstieg eines Enzymsystems, das Äpfelsäure decarboxyliert, wenn Schalenstücke von einer Frucht hinzugegeben werden. Dieselbe Entwicklungsfolge von enzymatischen Prozessen erfolgt in Geweben von Apfelschalenscheiben, die von Äpfeln im präklimakterischen Stadium stammen und 24 Stunden einem Alterungsprozess unterworfen wurden.

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Resume La crise respiratoire et la maturation des pommes sont décrites. Il est suggéré que la distinction entre fruits du type climactérique et ceux du type non-climactérique est plus apparente que réelle. Chez les pommes, il existe une séquence de changements dans l'activité enzymatique tout au long du climactérique; cette séquence commence par une production augmentée d'éthylène. L'augmentation de respiration est suivie par un pic dans l'incorporation d'acides aminés dans les protéines; ce pic est lui-même suivi, au sommet de la crise climactérique, par une forte augmentation d'activité d'un système pouvant décarboxyler du malate ajou té à des fragments de pelures détachés du fruit. Le même type de développement séquentiel des processus enzymatiques a lieu dans des disques de pelure de pomme prélevés sur des fruits préclimactériques et mis à vieillir durant 24 heures.

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Much of the work described in this paper was carried out at Ditton Laboratory before our transfer to the Food Research Institute in 1965.  相似文献   

The evolving story of Mycobacterium tuberculosis clade members detected in fish     

Kaattari IM  Rhodes MW  Kaattari SL  Shotts EB 《Journal of fish diseases》2006,29(9):509-520

Advances in molecular analyses have permitted documentation of an increasing spectrum of mycobacteria infecting fish. Although some of these mycobacteria are not closely related, several species belong to the Mycobacterium tuberculosis clade. One member of the clade, M. marinum, is well known as an agent of piscine mycobacteriosis. Three other clade species, M. shottsii, M. pseudoshottsii and M. 'chesapeaki', have recently been identified as predominant disease agents in a widespread, continuing epizootic in wild striped bass of the Chesapeake Bay. A fifth clade member, M. ulcerans, has recently been indirectly detected in wild, African cichlid fish. As M. ulcerans is the third most common human mycobacterial infection worldwide, even such indirect evidence of M. ulcerans in fish must be more thoroughly investigated. Complicating the differentiation of these clade members is the growing recognition of intraspecies and interspecies variation in phenotypes, genes and virulence. Thus, researchers must be aware of the variety of piscine isolates within the M. tuberculosis clade. This review summarizes the methods of detection and differentiation for this important group of mycobacteria.  相似文献   

Effects of different feed management treatments on water quality for Pacific white shrimp Litopenaeus vannamei          下载免费PDF全文

Lauren N Jescovitch  Carter Ullman  Melanie Rhodes  Donald Allen Davis 《Aquaculture Research》2018,49(1):526-531

Increasing feeding rates may provide an increase in production, thus nutrients such as nitrogen, phosphorus and organic matter will also increase. These nutrients promote a greater oxygen demand and concentrations of toxic metabolites which can lead to frequent problems with low dissolved oxygen and an abundance of blue‐green algae. Four feed management practices were evaluated among sixteen 0.1 ha ponds culturing Pacific white shrimp (Litopenaeus vannamei). Feeding treatments included hand feeding using the Standard Feeding Protocol (SFP), SFP plus 15% from 8 to 16 weeks, an automatic‐solar timer which fed SFP+15%, and an AQ1 acoustic demand feeder allowing up to 12 kg/day·pond based on shrimps feeding response. Samples were analysed at weeks 0, 4 and 8–16 for the following parameters: chlorophyll a, total ammonia nitrogen, nitrite–nitrogen, nitrate–nitrogen, total nitrogen, total phosphorus, soluble reactive phosphorus, total suspended solids, total suspended volatile solids, turbidity, conductivity, salinity and biological oxygen demand. Samples were collected and shipped overnight to Auburn, Alabama for off‐site analysis. On‐site water quality was also obtained at the farm. The AQ1 acoustic demand feeder produced the most shrimp with a yield of 4,568 kg/ha; however, the AQ1 also had the highest total ammonia nitrogen and nitrite–nitrogen levels late in the growing season. The AQ1 feeder may be a viable, reduced labour and cost alternative for the shrimp commercial industry; however, such technologies must also be matched to the ability of the production system to process nutrients.  相似文献   

Is GRO J1744-28 a strange star?     

KS Cheng  ZG Dai  DM Wei  T Lu 《Science (New York, N.Y.)》1998,280(5362):407-409

The unusual hard x-ray burster GRO J1744-28 recently discovered by the Compton Gamma-Ray Observatory can be modeled as a strange star with a dipolar magnetic field of 相似文献   

In situ measurements of organics, meteoritic material, mercury, and other elements in aerosols at 5 to 19 kilometers   总被引：1，自引：0，他引：1  

DM Murphy  DS Thomson  MJ Mahoney 《Science (New York, N.Y.)》1998,282(5394):1664-1669

In situ measurements of the chemical composition of individual aerosol particles at altitudes between 5 and 19 kilometers reveal that upper tropospheric aerosols often contained more organic material than sulfate. Although stratospheric aerosols primarily consisted of sulfuric acid and water, many also contained meteoritic material. Just above the tropopause, small amounts of mercury were found in over half of the aerosol particles that were analyzed. Overall, there was tremendous variety in aerosol composition. One measure of this diversity is that at least 45 elements were detected in aerosol particles. These results have wide implications for the complexity of aerosol sources and chemistry. They also offer possibilities for understanding the transport of atmospheric aerosols.  相似文献   

Presence and diversity of mixed avian Plasmodium spp. infections in introduced birds whose distribution overlapped with threatened New Zealand endemic birds     

ER Schoener  DM Tompkins  KA Parker  I Castro 《New Zealand veterinary journal》2020,68(2):101-106

ABSTRACT

Aims: To determine the presence of infection and co-infection of Plasmodium lineages in introduced birds at translocation sites for the North Island saddleback (Philesturnus rufusater), to investigate their role as Plasmodium spp. reservoirs.

Methods: Blood samples were collected from introduced bird species, with a special focus on blackbirds (Turdus merula) and song thrushes (Turdus philomelos), at six locations in the North Island of New Zealand that were the origin, or translocation sites, for North Island saddleback. Where available, blood smears were examined, and blood samples were tested using nested PCR with subsequent sequence analysis, for the presence of Plasmodium spp.

Results: Of the 55 samples tested using PCR analysis, 39 (71%) were positive for Plasmodium spp., and 28/40 (62%) blood smears were positive for Plasmodium spp. Overall, 31 blood samples were from blackbirds with 28/31 (90%) samples positive for Plasmodium spp. Six distinct avian Plasmodium lineages were identified, including three cosmopolitan lineages; Plasmodium vaughani SYAT05 was detected in 16 samples, Plasmodium matutinum Linn1 in 10 samples and Plasmodium elongatum GRW6 in eight samples. Mixed infections with more than one lineage were detected in 12 samples. Samples from two Australian magpies (Gymnorhina tibicen) were positive for Plasmodium. sp. lineage MYNA02, previously not identified in New Zealand.

Conclusions and clinical relevance: This is the first report from New Zealand in which specific Plasmodium spp. mixed infections have been found in introduced birds. Co-infections with several cosmopolitan Plasmodium lineages were identified, as well as the first report in New Zealand of an exotic avian Plasmodium sp. lineage, in Australian magpies. Whilst the role of introduced birds in maintaining and spreading pathogenic avian malaria in New Zealand is unclear, there is a potential infection risk to native birds, especially where distributions overlap.  相似文献   

Replacement of fish oil with alternative lipid sources in plant‐based practical feed formulations for marine shrimp (Litopenaeus vannamei) reared in outdoor ponds and tanks          下载免费PDF全文

F. Soller  M.A. Rhodes  D.A. Davis 《Aquaculture Nutrition》2017,23(1):63-75

The objective of this study was to demonstrate the feasibility of partial substitution of menhaden fish oil by alternative lipid sources (soybean oil, poultry grease and flaxseed oil) in non‐marine protein‐based shrimp production diet, its influence on fatty acid profile and its final product flavour. Results for the pond study (17 weeks) showed no differences (P ≥ 0.05) in shrimp production among different test diets. Production ranged from 5070 to 5363 kg ha^?1; mean final weight, 18.0 to 21.6 g; weekly growth, 1.04 to 1.25 g; survival, 65.6 to 75.4%; and FCR, 1.37 to 1.45. Results from the tank trial (12 weeks) confirmed these findings, final weight, 13.8–14.8 g; weekly growth, 1.1–1.2 g; survival, 92.5–98.3%; FCR, 1.05–1.11; and final standing crop, 4738–5024 kg ha^?1. The fatty acids profiles of edible tail muscle reared on the various diets displayed a similar fatty acid profile to that of the diets. The sensory test showed no statistical differences in texture, appearance, aroma and flavour between the shrimp fed diets containing menhaden fish oil and soybean oil. These studies demonstrated that practical shrimp feeds containing non‐marine protein ingredients and a percentage of fish oil replaced by alternative lipid sources had no negative impact on mean final weight, weekly growth, survival, FCR, final standing crop, fatty acids profile and organoleptic properties of Litopenaeus vannamei.  相似文献   

Effects of various dietary levels of copper hydroxychloride on growth performance and tissue response in Pacific white shrimp Litopenaeus vannamei fed practical diets          下载免费PDF全文

Y. Zhou  M.A. Rhodes  J. Liu  D.A. Davis 《Aquaculture Nutrition》2017,23(1):171-180

Two trials were conducted to evaluate the performance of Pacific white shrimp Litopenaeus vannamei offered diets containing various copper (Cu) levels from Cu hydroxychloride (Cu₂(OH)₃Cl) containing 58.81% copper in the clear water recirculating system. In both trials, the basal diet (360 g kg^?1 protein, 80 g kg^?1 lipid) containing approximately 10 mg Cu kg^?1 was primarily comprised of fishmeal, soybean meal, corn protein concentrate and whole wheat. In trial 1, test diets were produced supplementing the basal diet with 5, 10, 20, 40 and 60 mg Cu kg^?1 from Cu hydroxychloride. Four replicate groups of 15 shrimp per tank (initial weight 0.28 g) were offered diets in slight excess over 8 weeks. In trial 2, the basal diet was supplemented with 30, 90, 150, 210 and 270 mg Cu kg^?1 from Cu hydroxychloride. Seven replicate groups of 15 shrimp per tank (initial weight 0.22 g) were offered feed in slight excess over 7 weeks. At the end of the two growth trials, no significant differences were observed in final biomass, final mean weight, percentage weight gain, feed conversion ratio (FCR) and survival. In trial 1, the Cu concentrations of the carapace, hepatopancreas and whole shrimp linearly increased with increasing dietary Cu supplements. In trial 2, polynomial regression of Cu concentrations of the carapace, hepatopancreas and whole shrimp against analysed dietary Cu content indicated that a plateau was reached at 215 mg analysed Cu kg^?1. Results of this study indicate that there was no negative effect of high levels of Cu supplement with regard to growth and survival. Tissue levels generally increased up to around 200 mg Cu kg^?1 diet and then decreased, possibly indicating a shift in physiology.  相似文献