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101.
Actinobacillus pleuropneumoniae, a gram-negative rod of the Pasteurellaceae family, causes pleuropneumonia in pigs. Establishing A. pleuropneumoniae free herds is difficult due to the occurrence of persistently infected animals. The ApxIV toxin is expressed by A. pleuropneumoniae in vivo and an ELISA based on the toxin is used to detect infection and to differentiate between infected and vaccinated animals. In this study, we have identified a 1070bp insertion element of the IS30 family, designated ISApl1, in the A. pleuropneumoniae serotype 7 strain AP76. ISApl1 contains a 924bp ORF encoding a transposase, which is flanked by 27bp inverted repeats showing six mismatches. We investigated the occurrence of ISApl1 in other A. pleuropneumoniae strains, and its possible interference with virulence associated factors. Four insertion sites were identified in AP76: within the apxIVA toxin ORF, within a putative autotransporter adhesin ORF, upstream of a capsular polysaccharide biosynthesis gene cluster, and downstream of a beta-lactamase gene. ISApl1 is also present in some serotype 7 field isolates, but not in reference or field strains of other serotypes. In A. pleuropneumoniae AP76, the transposase gene is transcribed in vitro. The insertion in the apxIVA toxin gene remains stable after animal passage. Since this insertion should disrupt toxin expression, we tested 7 pigs infected with AP76 at day 21 post-infection. All were negative in the ApxIV ELISA but four out of seven were positive in an ApxII toxin ELISA. These results show that insertion elements can affect the detection of A. pleuropneumoniae infected animals. 相似文献
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The bacterial flora of the normal canine vagina compared with that of vaginal exudates 总被引:1,自引:0,他引:1
The aerobic bacterial flora (excluding Mycoplasma spp.) of the vagina of sixty-two clinically normal bitches was determined and the species most frequently isolated, in decreasing order, were: Escherichia colt , Streptococcus 'viridans', Staphylococcus aureus and Streptococcus cards .
From the vaginal exudates of seventy-two bitches with vaginitis, the order of frequency was: E. coli , Strep, canis and Staph. aureus .
The only consistent difference between the bacterial flora from the two sources was the relatively higher numbers of bacteria in the vaginal exudates. 相似文献
From the vaginal exudates of seventy-two bitches with vaginitis, the order of frequency was: E. coli , Strep, canis and Staph. aureus .
The only consistent difference between the bacterial flora from the two sources was the relatively higher numbers of bacteria in the vaginal exudates. 相似文献
104.
Roman Gebauer Daniel Volařík Josef Urban Isabella Børja Nina Elisabeth Nagy Toril Drabløs Eldhuset Paal Krokene 《European Journal of Forest Research》2014,133(1):111-120
Trees must respond to many environmental factors during their development, and light is one of the main stimuli regulating tree growth. Thinning of forest stands by selective tree removal is a common tool in forest management that increases light intensity. However, morphological and anatomical adaptations of individual shoots to the new environmental conditions created by thinning are still poorly understood. In this study, we evaluated shoot morphology (shoot length, needle number, projected leaf area) and anatomy (tracheid lumen area, tracheid number, tracheid dimensions, xylem area, potential hydraulic conductivity) in three Norway spruce (Picea abies/L./Karst.) families exposed to different thinning regimes. We compared shoot characteristics of upper-canopy (i.e. sun-exposed) and lower-canopy (i.e. shaded) current-year shoots in a control plot and a plot thinned to 50 % stand density the previous year. One tree per family was chosen in each treatment, and five shoots were taken per canopy position. We found that upper-canopy shoots in both plots had higher values than lower-canopy shoots for all studied parameters, except lumen roundness and tracheid frequency (i.e. tracheid number per xylem area). Thinning had little effect on shoot morphology and anatomy 1 year after thinning, except for small but significant changes in tracheid dimensions. Needles were more sensitive to altered light conditions, as projected leaf area of shoot, needle number and leaf hydraulic conductivity changed after thinning. Differences between upper- and lower-canopy shoots did not seem to be influenced by thinning and were almost the same in both plots. Our results suggest that lower-canopy shoots require several years to modify their morphology and anatomy to new light conditions following thinning. The slow light adaptation of the lower canopy may be of practical importance in forest management: thinned stands may be predisposed to drought stress because newly exposed shoots experience increased illumination and transpiration after thinning. 相似文献
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Karpova NN Pickenhagen A Lindholm J Tiraboschi E Kulesskaya N Agústsdóttir A Antila H Popova D Akamine Y Bahi A Sullivan R Hen R Drew LJ Castrén E 《Science (New York, N.Y.)》2011,334(6063):1731-1734
Antidepressant drugs and psychotherapy combined are more effective in treating mood disorders than either treatment alone, but the neurobiological basis of this interaction is unknown. To investigate how antidepressants influence the response of mood-related systems to behavioral experience, we used a fear-conditioning and extinction paradigm in mice. Combining extinction training with chronic fluoxetine, but neither treatment alone, induced an enduring loss of conditioned fear memory in adult animals. Fluoxetine treatment increased synaptic plasticity, converted the fear memory circuitry to a more immature state, and acted through local brain-derived neurotrophic factor. Fluoxetine-induced plasticity may allow fear erasure by extinction-guided remodeling of the memory circuitry. Thus, the pharmacological effects of antidepressants need to be combined with psychological rehabilitation to reorganize networks rendered more plastic by the drug treatment. 相似文献
107.
In recent years there has been an increased focus on sustainable farming systems. This has led to an increase in the use of farm models built to assess the environmental impact from farming. In whole-farm models including crop production it is important to consider the rotation of crops, since this has a major impact on the consequences of the crop production. 相似文献
108.
Summary The inheritance of root rot resistance in red raspberry, caused by Phytophtora fragariae var. rubi, was investigated using two experimental breeding designs. Design A was not randomly mated and genetic parameters could not be calculated. Design B was therefore randomly mated to make it possible to do such estimations. Considerable genetic variation was associated with the recorded traits on seedlings tested in a glasshouse. Disease index and % survival were both found to be highly heritable with broad sense heritabilities (H2) close to 0.9 in each design. Estimates of narrow sense heritability (h2), indicated that progress towards resistance would be moderate. In the first design the cultivars Festival, Asker, Boyne and Sentry and the clones N85-02-13 and N85-06-140 had high general combining abilities. Some crosses had a high specific combining ability indicating the presence of non-additive genetic variation. 相似文献
109.
Jennifer Eiermann BVSc Kristin Kirkby-Shaw DVM MS PhD DACVS-SA DACVSMR CCRT Richard B. Evans PhD Sebastian C. Knell Dr med vet DECVS Michael P. Kowaleski DVM DACVS DECVS Philipp A. Schmierer Dr med vet DECVS Mary S. Bergh DVM DACVS DACVSMR Jason Bleedorn DVM MS DACVS Laura C. Cuddy MVB MS DACVS-SA DECVS DACVSMR DECVSMR MRCVS Nina R. Kieves DVM DACVS-SA DACVSMR CCRT Peter Lotsikas DVM DACVS DACVSMR Antonio Pozzi DVM MS DACVS DECVS DACVSMR 《Veterinary surgery : VS》2020,49(1):80-87
110.