Microvascular anatomy of ovary and oviduct in the adult African Clawed Toad (Xenopus laevis DAUDIN, 1802)–Histomorphology and scanning electron microscopy of vascular corrosion casts     

Alois Lametschwandtner  Bernd Minnich 《Anatomia, histologia, embryologia》2020,49(6):742-748

Ovaries and oviducts of the adult African Clawed Toad (Xenopus laevis DAUDIN, 1802) were studied by light microscopy (LM) of paraplast embedded tissue sections and scanning electron microscopy (SEM) of vascular corrosion casts (VCCs). Histomorphology revealed that ovarian vessels located in the thecal layers. Ovarian and interlobar arteries displayed a horse-shoe shaped longitudinally running bundle of vascular smooth muscle cells. Follicular blood vessels showed flattened profiles, which were confirmed by scanning electron microscopy in vascular corrosion casts. The flattened profiles obviously led to high intravasal pressures, which locally prevented filling of the follicular capillary bed. Oviduct arteries pierced the fibrous stroma surrounding the oviduct mucosa. In the pars convoluta, the mucosa consisted of a ciliated simple columnar epithelium and tubular oviduct glands that opened between ciliated epithelial cells into the oviduct lumen. Oviduct arteries branched at the basolateral surfaces of tubular glands. After a short tangential course, arterioles branched into capillaries which ran radially between oviduct glands towards the subepithelium. Anastomoses at different heights connected capillaries of neighbouring glands. Subepithelially, capillaries ran longitudinally and undulated. Postcapillary venules radiated centrifugally towards the stroma to finally drain into oviduct veins located in the stroma. Oviduct vascular densities clearly reflected non-ovulatory and ovulatory states.  相似文献   

改良半薄切片法观察胡杨种子结构   总被引：1，自引：0，他引：1  

伊丽米努尔  Kurt Zogauer  Bernd Cyffca  史军辉 《西部林业科学》2013,42(2)

胡杨是干旱荒漠区唯一成林的优势树种.为深入研究胡杨种子的结构,采用改良半薄切片法,使用乙二醇-甲基丙烯酸酯(GMA)为包埋剂对胡杨种子形态和结构进行了观察研究.观察研究表明,应用改良半薄切片法观察胡杨种子结构的效果良好.以此清晰地观察到成熟的胡杨种子由种皮、子叶、胚轴和胚根组成,种皮由一层或多层薄壁细胞构成.并可从超微结构上了解胡杨种子成熟过程储备物质的变化特征.对利用胡杨种子繁殖造林增扩胡杨资源具有重要的理论与实践意义.  相似文献   

Condition-dependent transcriptome reveals high-level regulatory architecture in Bacillus subtilis     

Nicolas P  Mäder U  Dervyn E  Rochat T  Leduc A  Pigeonneau N  Bidnenko E  Marchadier E  Hoebeke M  Aymerich S  Becher D  Bisicchia P  Botella E  Delumeau O  Doherty G  Denham EL  Fogg MJ  Fromion V  Goelzer A  Hansen A  Härtig E  Harwood CR  Homuth G  Jarmer H  Jules M  Klipp E  Le Chat L  Lecointe F  Lewis P  Liebermeister W  March A  Mars RA  Nannapaneni P  Noone D  Pohl S  Rinn B  Rügheimer F  Sappa PK  Samson F  Schaffer M  Schwikowski B  Steil L  Stülke J  Wiegert T  Devine KM  Wilkinson AJ  van Dijl JM  Hecker M  Völker U  Bessières P 《Science (New York, N.Y.)》2012,335(6072):1103-1106

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MR-imaging of lumbosacral intervertebral disc degeneration in clinically sound German shepherd dogs compared to other breeds     

Amort KH  Ondreka N  Rudorf H  Stock KF  Distl O  Tellhelm B  Kramer M  Wigger A 《Veterinary radiology & ultrasound》2012,53(3):289-295

German shepherd dogs are overrepresented in the group of dogs with cauda equina compression syndrome due to degenerative lumbosacral stenosis. A congenital predisposition for early degeneration of the lumbosacral intervertebral disc has been suspected. Our aims were to assess the morphologic appearance of the lumbosacral intervertebral disc and the lumbosacral junction in healthy German shepherd dogs compared to other breeds and to evaluate for an early onset of degenerative changes. The lumbosacral spine of 110 clinically sound German shepherd dogs and 47 healthy dogs of other large breeds was examined using magnetic resonance (MR) imaging. The degeneration of every intervertebral disc was graded using an established classification system. Signal intensity of the entire lumbosacral disc and the nucleus pulposus was determined independently. Lumbosacral malalignment was assessed according to a previously described method. The findings for the German shepherd dogs were compared to those of the other breeds. Although most dogs were younger than 18 months at the date of examination, significantly higher grades of degeneration were detected for the lumbosacral intervertebral disc of German shepherd dogs (P < 0.003). Degeneration of the lumbosacral intervertebral disc was independent from findings in the other lumbar discs. We conclude that the German shepherd dog has a predisposition for degenerative changes in the lumbosacral intervertebral disc.  相似文献   

Perspectives on molecular detection methods of lyssaviruses     

Fischer M  Hoffmann B  Freuling CM  Müller T  Beer M 《Berliner und Münchener tier?rztliche Wochenschrift》2012,125(5-6):264-271

Lyssaviruses belong to the family Rhabdoviridae within the order Mononegavirales. Their genomes consist of a negative stranded linear RNA. Although dog transmitted rabies causes the majority of the estimated 55 000 worldwide fatalities per year, bat lyssaviruses have also caused human cases. Based on a broad range of different host species, their geographical distribution and the evolutionary age lyssaviruses display a high degree of genetic variability. Thus the development of molecular diagnostics for the reliable detection and identification of members of the genus Lyssavirus (pan-lyssavirus assay) is a challenge, but is valuable for the fight against rabies worldwide. In this study different published PCR-systems or primers for the detection of a wide range of lyssaviruses were tested as real-time RT-PCRs with different one-step and two-step assays. Comparison of different two-step assays by varying the RT-chemistry revealed differences in sensitivity. Nevertheless, most of the tested one-step systems provided an improved performance, including a reduced assay time and a reduced risk of cross-contaminations, when compared to the optimized two-step assay. Finally, we also provide an overview of additional state-of-the-art molecular methods to detect and differentiate lyssavirus species in general.  相似文献   

Identification of differentially expressed protective genes in liver of two rainbow trout strains     

Rebl A  Verleih M  Korytář T  Kühn C  Wimmers K  Köllner B  Goldammer T 《Veterinary immunology and immunopathology》2012,145(1-2):305-315

Since 1975, the rainbow trout strain BORN (Germany) has been bred in brackish water from a coastal form imported from Denmark. Accompanying phenotypic monitoring of the adapted BORN trout until now revealed that this selection strain manifested a generally elevated resistance towards high stress and pathogenic challenge including lower susceptibility towards Aeromonas salmonicida infections in comparison to other trout strains in local aqua farms. We focus on the elucidation of both, genetic background and immunological basis for the increased survivorship to infections. A first comparison of gene expression profiles in liver tissue of healthy rainbow trout from the local selection strain BORN and imported trout using a GRASP 16K cDNA microarray revealed six differentially expressed genes evoking pathogen and wounding responses, LEAP2A (encoding for liver-expressed antimicrobial peptide), SERPINA1 (alpha-1 antitrypsin), FTH1 (middle subunit of ferritin), FGL2 (fibroleukin), CLEC4E (macrophage-inducible C-type lectin), and SERPINF2 (alpha-2 antiplasmin). Since the latter gene is not described in salmonid species so far, our first aim was to characterize the respective sequence in rainbow trout. Two trout SERPINF2 genes were identified, which share only 48% identical amino acid residues and a characteristic SERPIN domain. Second, we aimed to analyse the expression of those genes after temperature challenge (8 °C and 23 °C). Only FTH1 was upregulated in BORN and import trout after increase of temperature, while SERPINA1 and FGL2 were only elevated in import trout. Third, the expression of all named genes was analyzed after pathogen challenge with A. salmonicida subsp. salmonicida. As a main finding, we detected a comparably faster regeneration of LEAP2A mRNA abundance in BORN trout following bacterial infection. Ingenuity Pathways Analysis suggested a functional interplay among the mentioned factors and the pro-inflammatory cytokine TNF, whose stronger expression was validated in liver of BORN trout. This data indicate that the examined genes contribute to an improved first barrier against invading pathogens in BORN trout.  相似文献   

Epizootic hemorrhagic disease virus infection of type I interferon receptor deficient mice     

Eschbaumer M  Keller M  Beer M  Hoffmann B 《Veterinary microbiology》2012,155(2-4):417-419

Type I interferon receptor deficient (IFNAR(-/-)) mice were infected with an Israeli isolate of serotype 7 of epizootic hemorrhagic disease virus (EHDV; Orbivirus, Reoviridae). Two out of two mice that received 5×10(5) 50% tissue culture infectious doses (TCID(50)) by intraperitoneal injection died or were euthanized in a moribund state on day 5 after infection. One mouse out of three that had been inoculated with 5×10(2) TCID(50) died on day 7 while the remaining mice did not show any clinical signs and survived until the end of the experiment. Spleens of all dead mice were highly positive in an EHDV real-time RT-PCR (quantification cycle values ≤15) and contained ≥10(5.8) TCID(50) of virus per ml of homogenate. The viral RNA content and virus titer in the spleens of the two surviving mice, on the other hand, were over 100-fold lower. Different from data reported for BTV, the outcome of EHDV infection of IFNAR(-/-) mice is dose-dependent and subclinical infections can occur.  相似文献   

Manganese efficiency and maganese‐uptake kinetics of raya (Brassica juncea), wheat (Triticum aestivum), and oat (Avena sativa) grown in nutrient solution and soil     

Mohammad Hassan Sayyari‐Zahan  Upkar Singh Sadana  Bernd Steingrobe  Norbert Claassen 《植物养料与土壤学杂志》2009,172(3):425-434

Manganese (Mn) deficiency is reported worldwide and often decreases crop yield. However, plant species differ in their susceptibility to Mn deficiency. Poaceae are often inefficient, whereas Brassicaceae seem to be efficient in Mn uptake. The objective of this paper was to determine the relevance of Mn‐uptake kinetics, root‐system size, and Mn mobilization for differences in Mn efficiency of wheat, oat, and raya. To determine Mn‐uptake kinetics, wheat (Triticum aestivum L. cv. PBW 343), raya (Brassica juncea L. cv. RLM 619), and oat (Avena sativa L. cv. Aragon) were grown in a growth chamber together in complete nutrient solution having an average Mn concentration of 90, 180, 360, 910, and 2270 nmol L^–1. For determining Mn efficiency of the three species in soil, the plants were grown for 22 d in pots filled with 3 kg of a loamy soil low in Mn availability (pH (CaCl₂) 7.4; DTPA‐extractable Mn: 3.5 mg (kg soil)^–1). The soil was fertilized with 0, 1, 2, 4, and 8 mmol Mn (kg soil)^–1 resulting in Mn soil‐solution concentrations ranging from 40 to 90 nmol L^–1, hence lower than in the solution experiment. In order to determine Mn soil‐solution concentration close to the root surface, the root length density was increased by growing two plants of raya and four plants of wheat in only 250 mL soil columns for 25 d. In solution culture at high concentrations, raya showed a higher Mn uptake compared to wheat and oat. However, at low Mn supply, all three species were comparably Mn‐efficient, i.e., plant growth was similar, and also the uptake was similar. In soil, the highest yield was achieved for raya in the unfertilized treatment whereas the Poaceae needed at least a fertilization of 1 mmol Mn (kg soil)^–1. The Poaceae showed a yield reduction of about 40% in the unfertilized treatment. Manganese concentration in the shoot dry weight was always higher in raya than in wheat or oat. This was due to a higher Mn uptake whereas relative shoot‐growth rate and root‐to‐shoot ratio were similar among the species. The higher Mn uptake of raya in soil was in contradiction to the comparable Mn‐uptake kinetics of the three crops at low Mn concentration in solution. This points to plant differences in their ability to affect Mn availability in the rhizosphere. In the bulk soil, all the crops decreased Mn solution concentration, but this effect was somewhat less for raya. But in the rhizosphere, raya increased Mn soil‐solution concentration significantly to 58 nmol L^–1, as compared to 37 nmol L^–1 of the unplanted control soil. In contrast, wheat showed a Mn solution concentration of 25 nmol L^–1 which was not significantly different from the control. The results indicate that differences in Mn efficiency among the crops studied are related to their ability to affect the solubility of Mn in the rhizosphere.  相似文献   

Organic carbon in soils of Germany: Status quo and the need for new data to evaluate potentials and trends of soil carbon sequestration     

Annette Prechtel  Margit von Lützow  Bernd Uwe Schneider  Oliver Bens  Claus G. Bannick  Ingrid Kögel‐Knabner  Reinhard F. Hüttl 《植物养料与土壤学杂志》2009,172(5):601-614

Uncertainties in estimates of soil carbon (C) stocks and sequestration result from major gaps in knowledge of C storage in soils, land‐use history, the variability of field measurements, and different analytical approaches applied. In addition, there is a lack of long‐term datasets from relevant land‐use systems. As in many European countries, a national database on soil organic carbon (SOC) including all relevant information for the determination of soil C stocks is likewise missing in Germany. In this paper, we summarize and evaluate the present state of knowledge on organic‐C contents/pools in soils of Germany and discuss the need for the acquisition and access to new data on soil organic carbon. Despite the number of agricultural sites under permanent soil monitoring, regional surveys on SOC, comprehensive ecosystem studies, and long‐term field experiments, there is a striking lack of data in Germany particularly with regard to agricultural soils. Apart from a missing standardization of methods and homogeneous baseline values, the implementation of a periodic, nation‐wide soil inventory on agricultural soils is required in order to simultaneously record information on land use, land‐use change, and agricultural practice. In contrast, the existing national inventory of forest soils provides information on C‐stock changes in forest soils, although there is some concern with regard to the representativeness of the sampling design to adequately address the problem of spatial heterogeneity and temporal variability. It is concluded that the lack of comprehensiveness, completeness, actuality, data harmonization, and standardized sampling procedures will further prevent the establishment of a SOC database in Germany with regard to the monitoring of trends in soil C pools and fluxes and the assessment of long‐term C‐sequestration potentials of soils under different land use. A future soil inventory should represent the heterogeneity of organic matter through functionally different SOC pools, topsoil characteristics as well as content, pool, and flux data for the deeper mineral‐soil compartments.  相似文献   

Chronology for the Aegean Late Bronze Age 1700-1400 B.C     

Manning SW  Ramsey CB  Kutschera W  Higham T  Kromer B  Steier P  Wild EM 《Science (New York, N.Y.)》2006,312(5773):565-569

Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology contrasts with conventional archaeological dates and cultural synthesis: stretching out the Late Minoan IA, IB, and II phases by approximately 100 years and requiring reassessment of standard interpretations of associations between the Egyptian and Near Eastern historical dates and phases and those in the Aegean and Cyprus in the mid-second millennium B.C.  相似文献