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81.
Diagnostic and typing options for investigating diseases associated with Pasteurella multocida 总被引:3,自引:0,他引:3
Pasteurella multocida is responsible for major animal diseases of economic significance in both developed and developing countries whereas human infections related to this bacterium are infrequent. Significantly, development of a carrier status or latent infections plays a critical role in the epidemiology of these diseases. Aiming at increased knowledge of these infections, we examine potential diagnostic and selected typing systems for investigating diseases caused by P. multocida. Detection of P. multocida from clinical specimen by; (i) isolation and identification, (ii) polymerase chain reaction (PCR), iii) specific hybridisation probes, (iv) serological tests and (v) other alternative methods is critically evaluated. These detection systems provide a wide spectrum of options for rapid diagnosis and for detecting and understanding of latent infections in herd/flock health control programmes, though PCR methods for detecting P. multocida in clinical specimen appear increasingly preferred. For establishing the clonality of outbreak strains, we select to discuss macromolecular profiling, serotyping, biotyping, restriction enzyme analysis, ribotyping and multiplex PCR typing. Although P. multocida infections can be rapidly diagnosed with molecular and serological tests, isolation and accurate species identification are central to epidemiological tracing of outbreak strains. Our review brings together comprehensive and essential information that may be adapted for confirming diagnosis and determining the molecular epidemiology of diseases associated with P. multocida. 相似文献
82.
83.
Live weight, body size and carcass characteristics of young bulls of fifteen European breeds 总被引:1,自引:1,他引:0
P. Albertí B. Panea C. Saudo J.L. Olleta G. Ripoll P. Ertbjerg M. Christensen S. Gigli S. Failla S. Concetti J.F. Hocquette R. Jailler S. Rudel G. Renand G.R. Nute R.I. Richardson J.L. Williams 《Livestock Science》2008,114(1):19-30
A total of 436 young bulls from fifteen Western European breeds, including beef, dairy and local types from five countries, were studied to assess variability in live weight, live weight gain, body measurements and carcass traits. Animals were logged indoors, and fed a diet based on concentrate and straw offered ad libitum from 9 months of age to slaughter at 15 months of age. The weight, body length, height at withers and pelvis width, of the animals were recorded at 9, 12 and 15 months of age. After slaughter, 15 carcass variables were recorded, including carcass weight, EU classification scores, morphological measurements and dissection data. Data were analysed by GLM, regression and principal component analysis procedures.Significant differences were found between breeds for all variables studied, however, the body size measurements and the carcass traits were more useful to discriminate among cattle breeds, than either live weight or daily gain. With respect to the body size and carcass traits the studied breeds could be grouped as:
- – Specialized beef breeds, comprising Piemontese, Asturiana de los Valles, Pirenaica, Limousin, South Devon, Charolais and Aberdeen Angus, all of which were characterized by high muscularity, wide pelvis and medium height and a low to medium level of fatness.
- – Local and dairy breeds, comprising Jersey, Casina, Highland, Holstein and Danish Red, the latter two breeds were tall animals, while the former three breeds were small in size. In general the group was poorly muscled and tended to have a high or medium level of fat.
- – Intermediate group, Avileña, Marchigiana and Simmental: these breeds were characterized by an intermediate muscle conformation and fatness level and were relatively tall.
84.
The tepals of 28 Chilean species of Alstroemeria and 183 interspecific hybrids were analysed for anthocyanin content by high-performance liquid chromatography (HPLC). The anthocyanins were identified as 3-rutinosides of 6-hydroxydelphinidin, 6-hydroxyeyanidin, cyanidin, and delphinidin and 3-glyeosides of cyanidin and delphinidin, some of which were acylated with malonic acid. Comparisons of the anthocyanin contents in parents and offspring showed that no anthocyanidin or acylation pattern was dominant, and that offspring values were close to mid-parent values for the percentage of malonated anthocyanins, whereas the inheritance of cyanidin, 6-hydroxycyanidin, and delphinidin seems more complicated. Flower colour, hue, and intensity were measured by CIELab in fresh tepals and compared with their anthocyanin content and the estimated flavonoid concentrations. Colour intensity was positively correlated with anthocyanin concentration. Compared with flowers containing exclusively cyanidin 3-glycosides, the hues of flowers with delphinidin 3-glycosides were bluer and with 6-hydroxycyanidin 3-glycosides redder, respectively. Both malonation of anthocyanin and co-pigmentation with flavonoids caused a shift to bluish hues, irrespective of the anthocyanidins. By quantifying both chemical and colorimetric characteristics a model for the effect of anthocyanin on Alstroemeria flower colour was established. Breeding of new cultivars of Alstroemeria is discussed. 相似文献
85.
Holm P.E. Christensen T.H. Lorenz S.E. Hamon R.E. Domingues H.C. Sequeira E.M. McGrath S.P. 《Water, air, and soil pollution》1998,102(1-2):105-115
Soil water concentrations of cadmium and zinc were measured in plant pots with 15 contaminated soils which differed in origin, texture, pH (5.1 – 7.8) and concentrations of cadmium (0.2 – 17 mg Cd kg-1) and zinc (36 – 1300 mg Zn kg-1). The soil waters contained total concentrations of 0.5 to 17 µg Cd L-1 and 9 to 3600 µg Zn L-1, which were dominated by free metal ions as measured by an ion exchange-resin method. Annual leaching outflows were estimated from soil water concentrations to be 0.5 – 17 g Cd ha-1 y-1 and 9 – 3600 g Zn ha-1 y-1 per 100 mm of net percolation, corresponding to 0.1% per year of the total soil content of cadmium and zinc. The measured soil water concentrations of cadmium and zinc did not correlate linearly with the corresponding soil concentrations but correlated fairly well with concentrations measured in Ca(NO3)2 extracts of the soils and with soil water concentrations estimated from soil concentrations and pH. Such concentration estimates may be useful for estimating amounts of cadmium and zinc being leached from soils. 相似文献
86.
The aim of this study was to examine interactions between Ascaris suum and Oesophagostomum dentatum infections in pigs with regard to population dynamics of the worms such as recovery, location and length; and host reactions such as weight gain, pathological changes in the liver and immune response. Seventy-two helminth-na?ve pigs were allocated into four groups. Group A was inoculated twice weekly with 10000 O. dentatum larvae for 8 weeks and subsequently challenge-infected with 1000 A. suum eggs, while Group B was infected with only 1000 A. suum eggs; Group C was inoculated twice weekly with 500 A. suum eggs for 8 weeks and subsequently challenge-infected with 5000 O. dentatum larvae, whereas Group D was given only 5000 O. dentatum larvae. All trickle infections continued until slaughter. Twelve pigs from Group A and B were slaughtered 10 days post challenge infection (p.c.i.) and the remaining 12 pigs from the each of the four groups were slaughtered 28 days p.c.i.. No clinical signs of parasitism were observed. The total worm burdens and the distributions of the challenge infection species were not influenced by previous primary trickle-infections with the heterologous species. Until day 10 p.c.i. the ELISA response between A. suum antigen and sera from the O. dentatum trickle infected pigs (Group A) pigs were significantly higher compared to the uninfected Group B. This was correlated with a significantly higher number of white spots on the liver surface both on Day 10 and 28 p.c.i. in Group A compared to Group B. The mean length of the adult O. dentatum worms was significantly reduced in the A. suum trickle infected group compared to the control group. These results indicate low level of interaction between the two parasite species investigated. 相似文献
87.
In a 1-year laboratory study of the New Zealand flatworm Arthurdendyus triangulatus, individual growth, degrowth and regrowth were manipulated via the feeding regime, with the compost worm Eisenia fetida as prey. A mean growth rate of 25 mg live weight wk—1 was evident, individual rates ranging between 18 and 38 mg wk−1. Degrowth was associated with egg capsule deposition for which the maximum rate was 0.5 capsules wk−1. The more egg capsules produced, the greater the adult weight loss, degrowth rates ranging from 8 to 55 mg wk−1. Change in flatworm body weight (gain/loss) also correlated with the length of the food introduction interval, though weight could be maintained for circa 2 weeks. Weight loss was not simply a function of hunger, voluntary cessation of feeding (possibly related to egg capsule production) being a confounding factor. During the growth phase, individual predation rate ranged from 0.9 to 1.1 earthworms wk−1, rate of tissue consumption ranging from 346 to 485 mg wk−1. Conversion efficiencies of earthworm to flatworm tissue were estimated to range between 3.8% and 10.7%. The impact of this exotic planarian on earthworm populations is discussed. 相似文献
88.
R. H. Bucholtz A. S. Meilvang T. Cedhagen J.T. Christensen D. J. Macintosh 《Journal of the World Aquaculture Society》2009,40(6):711-723
Aspects of the population biology of the mudskipper, Pseudapocryptes elongatus, (Cuvier, 1816) were studied in Bac Lieu Province in the Lower Mekong Delta, Vietnam, including sex ratio, length–frequency distribution, sexual dimorphism, hepatosomatic index (HSI), female gonadosomatic index (GSI), gonad histology, fecundity and some observations on post‐larvae and juveniles. In the population studied the sex ratio was skewed toward males. Females had a shorter mean length and a lower mean growth rate than males. No mature males or females were observed among mudskippers sampled in estuarine canals from February to May 2004 during the dry season. It is suggested that P. elongatus migrates to the sea to spawn later in the year after onset of the wet season. Salinity tolerance was evaluated in a 96‐h experiment. This showed that P. elongatus is remarkably euryhaline and able to survive in salinities ranging from freshwater to 50 ppt. Gut content analysis revealed that P. elongatus is a herbivore, feeding mainly on pennate diatoms (93% of the diet). 相似文献
89.
The existence of synthetic macrocyclic molecules with hydrophilic cavities containing multiple binding atoms and with hydrophobic exteriors gives rise to extraordinary possibilities with respect to the design and synthesis of molecules with specific cation and anion binding properties. The preparation of many new macrocyclic compounds has recently been reported, but few practical applications for them have been suggested. From the information available, it is becoming clear that it should be possible to synthesize macrocycles that will have specified, or selected, ion binding properties. Cavity size can be varied to accommodate only those cations or anions within a specified narrow band of sizes. Numbers and types of coordinating atoms can be chosen to give essentially electrostatic or covalent bonding or a combination of the two in a metalmacrocycle complex. The metal ligand bond appears to be predominantly ionic in the case of the cyclic polyethers but the covalent character increases on substitution of sulfur or nitrogen for oxygen donor atoms. The essential hydrophobic exteriors of the macrocycles can be modified by the addition of side chains and groups to facilitate the solution of anions and cations in organic solvents. The structures of many macrocycles can be made to approximate naturally occurring molecules, that is, cyclic polyethers similar to macrocyclic antibiotics of the valinomycin and nonactin types and cyclic polyamines similar to porphyrins. Macrocycles are also useful as model compounds for the study of metal interactions with biological systems. The synthetic macrocycles thus represent an intriguing new area of coordination chemistry, the systematic study of which should lead to many interesting and useful chemical applications in the field of metal complexation in solution. 相似文献
90.
Peter Sørensen Betina N. Pedersen Ingrid K. Thomsen Jørgen Eriksen Bent T. Christensen 《植物养料与土壤学杂志》2023,186(4):441-450