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51.
The Vsp proteins are the major outer membrane proteins of Brachyspira hyodysenteriae, the causative agent of swine dysentery. Eight vsp genes have been identified in B. hyodysenteriae strain B204, arranged into two four-gene loci, and at least two of the corresponding proteins are produced in vitro. The aims of this study were to characterise the vsp genes of the virulent Australian B. hyodysenteriae strain X576 and their corresponding proteins, Genomic sequence comparison with strains B204 and WA1 demonstrated that the number of vsp genes varies between B. hyodysenteriae strains, although the chromosomal locations of the vsp gene loci are consistent. We identified two additional vsp-like genes, designated vspI and vspJ, in each of the three strains. Double SDS-PAGE was used to demonstrate that Vsp proteins of B. hyodysenteriae strain X576 form multimeric protein complexes in the outer membrane that are stable in 6M urea but dissociate after boiling. The Vsp complexes primarily consisted of VspF but also contain VspE and VspI. VspD was also found in a series of complexes slightly larger than the more abundant VspF complexes. Vsp proteins are purported to be antigenic; however little direct data are available to support this claim. In this study convalescent pig sera did not bind denatured Vsp proteins by Western blotting, but did bind the Vsp complexes on Western blots, showing that conformational epitopes may be important in immune recognition of these major outer membrane proteins. This is the first definitive demonstration of the antigenicity of these proteins in swine dysentery.  相似文献   
52.
We estimated the date of onset (Date(est)) of cambial activity by the pinning method in Scots pine (Pinus sylvestris L.) trees at Vanttauskoski (Site 1) and Laanila (Site 2) near the latitudinal limit of Scots pine in northern Finland. In each year and at each site, observations were made on a different set of five trees. The estimated dates of onset of cambial activity were compared with the corresponding heat sums, calculated in degree-days according to two models. Within years, Date(est) varied among trees by up to 15 days at Site 1 and up to 13 days at Site 2. Among years, mean Date(est) varied by 15.3 days at Site 1 and 12.0 days at Site 2. The overall mean Date(est) differed between sites by 6 days (June 5 at Site 1 and June 11 at Site 2). Among all trees in all years, the mean number of degree days (d.d.) calculated from mean daily temperature above a threshold of 5 degrees C before Date(est) ranged from 68.7 to 135 d.d. at Site 1 and from 37.4 to 154.7 d.d. at Site 2. Among years, the mean heat sum before Date(est )ranged from 94 to 112.5 d.d. at Site 1 and from 61.4 to 136 d.d. at Site 2. Variation among years in heat sum before Date(est) at Site 2 was highly significant, indicating that one or more factors other than, or in addition to, heat sum determines the onset of cambial activity in Scots pine. Similar results were obtained when heat sum was computed from the area between the sine wave generated by daily maximum and minimum temperature and the threshold temperature.  相似文献   
53.
The soil conditions of an abandoned shunting yard in the Ruhr area were studied to find the most important factors influencing plant growth and nutrient cycling. The chemical and physical conditions of five Urbic Anthrosols with different development histories were compared with those of a nearby Calcic Cambisol under agricultural use. In the second half of the 19th century, the ground level of the shunting yard site was raised about 2 m. The soils are now mainly Regosols, mostly well drained in the topsoil. The coarse material contents (>2 mm), which are up to 100% in base layers of railway tracks, and the quality of the man-made substrates (crushed rock, slags, ashes, coke) are the most important factors influencing plant growth. Poor physical structure and low contents of fine fraction (<2 mm) lead to low water storage. Together with a low available nutrient stock, these properties lead to poor establishment of vegetation. The burning of coal by steam engines produced highly polluted ashes that fill pore spaces in the railway ballast layers. All the investigated fine substrata of the shunting yard layers exhibit a higher magnetic susceptibility than the rural soil. The ashes still contain unburned coal so that, although the total organic C content of the man-made soils reaches 37%, the wide C:N ratio does not indicate the actual quality of humic substances. The acid neutralization potential of the topsoil layers of the shunting yard will be consumed by acidic atmospheric deposition within a few decades, whereas in the surrounding Calcic Cambisols, it will take more than a thousand years. This may cause further problems of groundwater quality, as the heavy metals will become more soluble. The low soil quality makes such sites suitable for vegetation species that cannot compete in the surrounding very eutrophic agricultural landscape.  相似文献   
54.
Sinusitis is a common disorder in horses and may result from trauma, dental diseases, or space-occupying lesions. Radiography can only provide a limited amount of information. Computed tomography (CT) has been documented as an alternative imaging method. Eighteen horses (mostly Warmblood) with signs of chronic sinusitis were examined preoperatively with CT to assist in diagnosis of the underlying cause. There was a group of common CT features in horses with dental disease and sinusitis. The first molar was the most frequently affected maxillary cheek tooth. Hypoattenuation of the cementum, destruction of the enamel, and filling of the infundibular cavity with gas were the most frequent CT findings associated with caries. Gas bubbles within the bulging root area or fragmentation of the root in combination with swelling of the adjacent sinus lining were the most important CT features of dental decay. CT findings associated with sinusitis included excessive thickening of the respiratory epithelium in the rostral maxillary sinus; the caudal maxillary sinus was less often involved. The infraorbital canal, the nasomaxillary duct, and the frontomaxillary aperture were usually involved. The maxillary bone, however, especially the facial crest, was involved in nearly every horse, being characterized by endosteal sclerosis, thickening, periosteal reaction, and deformation leading to facial swelling in chronic infections. CT images allowed identification of involvement of individual teeth more clearly to reveal the diseased one for treatment. Three-dimensional imaging allowed improved understanding of the extent and severity of the pathologic change.  相似文献   
55.
56.
Die Ausformung der Grünlandvegetation wird in entscheidendem Maße von den Grundwasserständen bestimmt. Die Nutzung spielt aber eine außerordentlich große Rolle bei entsprechenden Modifikationen. Ebenso ist wesentlich, welche Arten im Ausgangsbestand etabliert sind oder im Bodensamenvorrat bzw. als Diasporen vorkommen. Der Gesamtwasserverbrauch von Pflanzenbeständen wird durch komplizierte Wechselwirkungen zwischen Artenzusammensetzung und Nutzungsweise bestimmt. Mähbestände mit zweimaliger Nutzung benötigten in allen Versuchsjahren eindeutig mehr Wasser als Weidebestände, die viermal abgeweidet wurden. Im Ertrag gab es nur geringe Unterschiede zu Gunsten der Mähnutzung. Aus qualitativer Sicht ist das physiologisch jüngere Weidefutter überlegen. Im speziellen Wasserverbrauch bestätigte sich die Weide als wassersparende Variante der Niedermoorbewirtschaftung. Hochwüchsige und massereiche Mähbestände benötigen sehr viel Wasser, das in nordostdeutschen Niedermooren nur über Fremdwasserzufuhr bereitgestellt werden kann. Auch aus der Sicht des Bodenschutzes (Verdichtung, besserer kapillarer Wasseraufstieg, Reduktion der NO 3 -Freisetzung usw.) sollte die Weide die bestimmende Form der extensiven Grünlandnutzung sein.  相似文献   
57.
Zusammenfassung Im Mai 1970 traten im Bereich eines Textil-Veredlungswerkes auffällige Schädigungen an der Vegetation von Hausgärten auf. Das Schadbild entsprach einer Wuchsstoffeinwirkung; die Empfindlichkeit der Pflanzen war unterschiedlich. Anhand von Labor- und Gewächshaustesten konnte als Ursache die Immission eines Fä rbereihilfsmittels (Carrier) angenommen werden; es handelte sich dabei um einen substituierten Aromaten.
Summary Injuries to vegetation caused by a substance (Carrier) used for textile dyeing. In may 1970 an extraordinary case of injury to vegetation in the range of a textile dye-work occured. The symptoms were equal to those induced by auxins. A so called carrier substance, it concerned a substituted aromate, was indicated as causal agent.
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59.
Submerged microbial cultures were screened for their potential to oxifunctionalize alpha-farnesene. The major oxidation product in all transforming cultures, 3,7,11-trimethyldodeca-1,3(E),5(E)10-tetraen-7-ol, showed a pleasant citrus-like odor and peak concentrations of 170 mg L-1. An Aspergillus niger isolate from mango generated another two terpene alcohols identified as diastereomeric menth-1-en-3-[2-methyl-1,3-butadienyl]-8-ol, a new natural compound with an apricot-like odor. The regiospecifity of the oxygen attack with concurrent lack of stereoselectivity suggested that the initial step of the bioconversion resembled the chemical autoxidation starting with the generation of an intermediate resonance-stabilized carbon-centered radical or carbocation.  相似文献   
60.
Innate immune responses are vital for pathogen defense but can result in septic shock when excessive. A key mediator of septic shock is tumor necrosis factor-α (TNFα), which is shed from the plasma membrane after cleavage by the TNFα convertase (TACE). We report that the rhomboid family member iRhom2 interacted with TACE and regulated TNFα shedding. iRhom2 was critical for TACE maturation and trafficking to the cell surface in hematopoietic cells. Gene-targeted iRhom2-deficient mice showed reduced serum TNFα in response to lipopolysaccharide (LPS) and could survive a lethal LPS dose. Furthermore, iRhom2-deficient mice failed to control the replication of Listeria monocytogenes. Our study has identified iRhom2 as a regulator of innate immunity that may be an important target for modulating sepsis and pathogen defense.  相似文献   
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