Allergic Pneumonitis in a Dog          下载免费PDF全文

J. M. Baker  A. B. Johansson 《Canadian journal of veterinary research》1962,26(3):64-65

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An attempt to prevent acute toxoplasmosis in macropods by vaccination with Hammondia hammondi     

GL REDDACLIFF  SJ PARKER  JP DUBEY  PJ NICHOLLS  AM JOHNSON  DW COOPER 《Australian veterinary journal》1993,70(1):33-35

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A Retention Bar For A Dislocated Hip In A Dog   总被引：1，自引：0，他引：1       下载免费PDF全文

Malcolm Baker  Arne B. Johansson 《Canadian journal of veterinary research》1958,22(7):229-231

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Antimicrobial susceptibility of Swedish, Norwegian and Danish isolates of Clostridium perfringens from poultry, and distribution of tetracycline resistance genes     

Johansson A  Greko C  Engström BE  Karlsson M 《Veterinary microbiology》2004,99(3-4):251-257

This study was undertaken to determine the in vitro susceptibility of Clostridium perfringens, isolated from poultry to antimicrobials used in poultry production. The minimal inhibitory concentration (MIC) of eight antimicrobials, including the ionophoric coccidiostat narasin, was determined for 102 C. perfringens isolates, 58 from Sweden, 24 from Norway and 20 from Denmark. Susceptibility to each antimicrobial compound was determined by broth microdilution. The isolates were obtained from broilers (89), laying hens (9) and turkeys (4), affected by necrotic enteritis (NE) or by C. perfringens associated hepatitis (CPH), and from healthy broilers. All strains, regardless of origin, proved inherently susceptible to ampicillin, narasin, avilamycin, erythromycin and vancomycin. A low frequency of resistance to virginiamycin and bacitracin was also found. Resistance to tetracycline was found in strains isolated in all three countries; Sweden (76%), Denmark (10%) and Norway (29%). In 80% of the tetracycline-resistant isolates, the two resistance genes tetA(P) and tetB(P) were amplified by PCR whereas in 20% only the tetA(P) gene was detected. No tetM gene amplicon was obtained from any of the tetracycline-resistant isolates. The uniform susceptibility to narasin revealed in this study shows that the substance can still be used to control clostridiosis. In this study, C. perfringens also showed a low degree of resistance to most other antimicrobials tested. Despite the small amounts of tetracycline used in poultry, a considerable degree of resistance to tetracycline was found in C. perfringens isolates from Swedish broilers.  相似文献   

Genetic parameters for calving difficulty, stillbirth, and birth weight for Hereford and Charolais at first and later parities   总被引：1，自引：0，他引：1  

Eriksson S  Näisholm A  Johansson K  Philipsson J 《Journal of animal science》2004,82(2):375-383

The aim of this study was to estimate direct and maternal genetic parameters for calving difficulty score, stillbirth, and birth weight at first and later parities for Charolais and Hereford cattle in Sweden. Calving traits have long been recorded for pure-bred beef cattle in Sweden, but only birth weight has been used in the selection in order to avoid calving difficulties. Linear animal model analyses included records on birth weight for 60,309 Charolais and 30,789 Hereford calves born from 1980 to 1999, and calving traits for 74,538 Charolais and 37,077 Hereford calves born from 1980 to 2001. The frequencies of difficult calvings and stillbirths were approximately 6% at first and 1 to 2% at later parities for both breeds. Fewer than half the stillborn calves were born from difficult calvings. Heritabilities estimated for birth weight in different univariate and bivariate analyses for Charolais and Hereford calves born at first and later parities ranged from 0.44 to 0.51 for direct effects and 0.06 to 0.15 for maternal effects. Heritabilities on the observable scale for calving difficulty score of Charolais and Hereford, scored in three classes, ranged from 0.11 to 0.16 for direct and 0.07 to 0.12 for maternal effects at first parity, and lower at later parities. All estimated heritabilities for stillbirth were very low (0.002 to 0.016 on the observable scale). Direct-maternal genetic correlations were negative, with few exceptions. Genetic correlations between the traits and between parities within traits were generally moderate to high and positive. Calving difficulty score should be included in the genetic evaluation of beef breeds in Sweden, whereas progeny groups in Swedish beef populations are too small for stillbirth to be considered directly.  相似文献   

Genetic relatedness and netB prevalence among environmental Clostridium perfringens strains associated with a broiler flock affected by mild necrotic enteritis     

Engström BE  Johansson A  Aspan A  Kaldhusdal M 《Veterinary microbiology》2012,159(1-2):260-264

In a previous study we investigated pulsed-field gel electrophoresis (PFGE) genotype diversity and prevalence of the netB toxin gene in Clostridium perfringens (CP) isolates recovered from a broiler flock (flock 1) affected by necrotic enteritis (NE). In this follow-up work, we examined samples collected before placement of flock 1, to see if NE during rearing could be traced back to the cleaned and empty building or the day-old chicks. Litter from the next flock in the same building (flock 2) was also examined. We detected 25 different PFGE genotypes, five of which were found only in litter from flock 2. Six genotypes which had been found in flock 1 during rearing were detected in samples collected before placement. NetB positive isolates belonging to two of these genotypes had been recovered from NE lesions during rearing, suggesting that virulent strains were transmitted from the cleaned and disinfected broiler house. NetB frequency among isolates from the empty building was 45%, indicating that netB positive strains were prevalent in a building that previously had housed a healthy flock offered in-feed narasin (flock 0). NetB frequency among isolates from litter used by flock 2 was 22%, indicating that netB positive strains were present in the environment of a 14-days-old healthy flock offered in-feed narasin. Two prevalent genotypes were consistently either netB negative or netB positive. However, the presence of genotypes represented by both negative and positive isolates may suggest that the gene can spread horizontally among different CP strains.  相似文献   

Modeling carbon allocation in trees: a search for principles     

Franklin O  Johansson J  Dewar RC  Dieckmann U  McMurtrie RE  Brännström A  Dybzinski R 《Tree physiology》2012,32(6):648-666

We review approaches to predicting carbon and nitrogen allocation in forest models in terms of their underlying assumptions and their resulting strengths and limitations. Empirical and allometric methods are easily developed and computationally efficient, but lack the power of evolution-based approaches to explain and predict multifaceted effects of environmental variability and climate change. In evolution-based methods, allocation is usually determined by maximization of a fitness proxy, either in a fixed environment, which we call optimal response (OR) models, or including the feedback of an individual's strategy on its environment (game-theoretical optimization, GTO). Optimal response models can predict allocation in single trees and stands when there is significant competition only for one resource. Game-theoretical optimization can be used to account for additional dimensions of competition, e.g., when strong root competition boosts root allocation at the expense of wood production. However, we demonstrate that an OR model predicts similar allocation to a GTO model under the root-competitive conditions reported in free-air carbon dioxide enrichment (FACE) experiments. The most evolutionarily realistic approach is adaptive dynamics (AD) where the allocation strategy arises from eco-evolutionary dynamics of populations instead of a fitness proxy. We also discuss emerging entropy-based approaches that offer an alternative thermodynamic perspective on allocation, in which fitness proxies are replaced by entropy or entropy production. To help develop allocation models further, the value of wide-ranging datasets, such as FLUXNET, could be greatly enhanced by ancillary measurements of driving variables, such as water and soil nitrogen availability.  相似文献   

Detection of Mycobacterium avium subsp. paratuberculosis in tissue samples by single, fluorescent and nested PCR based on the IS900 gene     

Englund S  Bölske G  Ballagi-Pordány A  Johansson KE 《Veterinary microbiology》2001,81(3):257-271

The aim of this study was to determine if fluorescent PCR could be used instead of nested PCR, for the detection of Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) in clinical specimens, to improve the sensitivity without increasing the risk for cross-contamination. We investigated and compared the sensitivity of single PCR, fluorescent PCR and nested PCR for the detection of IS900, an insertion sequence specific for M. paratuberculosis. A previously described extraction method for clinical specimens, based on xylene, was evaluated regarding its suitability for routine diagnostic work. The sensitivity of each PCR system was assessed by analysing a serial dilution of M. paratuberculosis DNA. To improve the reliability of the PCR and to facilitate the interpretation of the PCR results, a positive internal control molecule ("mimic") was developed and used for single and fluorescent PCR. In nested PCR, an existing mimic was used. The efficiency of recovering DNA of M. paratuberculosis from clinical specimens by the extraction method and detection of the organism by PCR was studied by analysing spiked ileum mucosa specimens. The final evaluation was performed on seventeen ileum mucosa specimens, previously found positive for M. paratuberculosis by bacterial culture. Twelve of the samples were positive by fluorescent PCR and nested PCR, and 10 samples were positive by single PCR. The use of mimics showed inhibition in specimens harbouring few M. paratuberculosis organisms, illustrating the effect of inhibitory substances in combination with small amounts of M. paratuberculosis DNA. We conclude that the extraction method was not adequate to recover small amounts of M. paratuberculosis and that inhibitory substances were still present in the processed specimens, but that the method is useful for identifying positive samples. Fluorescent PCR was a suitable alternative to both single PCR and nested PCR for the detection of M. paratuberculosis.  相似文献   

Pulmonary surfactant from healthy Belgian White and Blue and Holstein Friesian calves: biochemical and biophysical comparison     

Danlois F  Zaltash S  Johansson J  Robertson B  Haagsman HP  Rollin F  Ruysschaert JM  Vandenbussche G 《Veterinary journal (London, England : 1997)》2003,165(1):65-72

The biochemical composition and biophysical behaviour of pulmonary surfactant samples isolated from healthy Belgian White and Blue (BWB) and Holstein Friesian (HF) calves have been investigated and compared. Interesting differences in composition have been demonstrated. In particular, a higher level of total hydrophobic surfactant-associated proteins (SP) (due to higher levels of SP-B and SP-C) is reported in HF calves compared to BWB calves. Higher levels of phosphatidylcholine (PC) and especially the disaturated form of PC were also found in HF as compared to BWB calves. No immediate effect on the surface tension properties evaluated by the pulsating bubble surfactometer was found between the surfactant samples of the two breeds under physiological conditions. However, since a high content of disaturated PC and the presence of the SP-B and SP-C are thought to be essential for the surface activity, we propose that the reported modifications could contribute to the apparently lower resistance of the BWB calves to respiratory troubles in comparison with HF calves.  相似文献   

Combined effect of genetic and environmental factors on the accumulation of proteins in the wheat grain and their relationship to bread-making quality     

Ali Hafeez Malik  Ramune Kuktaite  Eva Johansson 《Journal of Cereal Science》2013

Bread-making quality of wheat flour is largely determined by the accumulation, concentration and composition of the proteins in the grain, which are influenced by genetic (G) and environment (E) variation and their interactions. We have therefore evaluated the importance of G and E factors and their interactions in determining the accumulation and composition of the proteins in the wheat grain. The cultivar determined development time (CDDT), together with the amount and timing of N application, played a significant role in determining the accumulation and final composition of the wheat grain proteins, explaining 21–59% of the variation. At low temperature, N application both at spike formation and at anthesis explained the highest proportion of variation (36%) in the percentage of sodium dodecyl sulphate (SDS) unextractable polymers in the total amount of polymers (% UPP), while at high temperature CDDT contributed most to the variation in % UPP (20%). The largest contributor to variation in the amount of total SDS extractable proteins (TOTE) was N application at anthesis, both at low and high temperatures (12% and 36%, respectively). Thus, the climate should be considered in recommendations for improving the protein quality and thereby the bread-making quality of wheat.  相似文献