Effect of hydrodynamics factors on sediment flocculation processes in estuaries     

Aisha Mhashhash  Bettina Bockelmann-Evans  Shunqi Pan 《Journal of Soils and Sediments》2018,18(10):3094-3103

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Phosphodiesterase isoenzymes in equine platelets and their influence on platelet adhesion     

Dunkel B  Rickards KJ  Page CP  Cunningham FM 《American journal of veterinary research》2007,68(12):1354-1360

OBJECTIVE: To determine the phosphodiesterase (PDE) isoenzymes in equine platelets and evaluate their influence on platelet adhesion. SAMPLE POPULATION: Platelets obtained from healthy New Forest Pony geldings that ranged from 12 to 20 years of age (mean +/- SEM, 17.3 +/- 1.1 years). PROCEDURES: PDE isoenzyme activity in equine platelets was determined by use of a 2-step radioactive assay. Functional importance of PDE isoenzymes was established by use of selective inhibitors in a colorimetric adhesion assay. RESULTS: PDE1, PDE2, PDE3, and PDE5 and small amounts of PDE4 were found in equine platelets. Inhibition of PDE3 abolished platelet adhesion almost completely, whereas inhibition of PDE4 and PDE5 had little effect. CONCLUSIONS AND CLINICAL RELEVANCE: Function of equine platelets can be influenced by inhibition of PDE3. Selective PDE3 inhibitors may be clinically useful to regulate platelet function. They offer the advantage of increased potency with fewer adverse effects, compared with those for nonselective PDE inhibitors.  相似文献   

Molecular subtype-specific clinical diagnosis of prion diseases     

Heinemann U  Krasnianski A  Meissner B  Gloeckner SF  Kretzschmar HA  Zerr I 《Veterinary microbiology》2007,123(4):328-335

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare transmissible disease caused by accumulation of pathological prion protein (PrP(sc)) in the CNS. According to the codon 129 polymorphism (methionine or valine) and the prion protein type 1 or 2, a classification into distinct subtypes was established. Further analysis of these subtypes detected atypical clinical forms with longer disease duration or younger age at onset. The CJD subtype influences sensitivity of the technical investigations such as 14-3-3 in CSF, periodic sharp wave complexes in the EEG or hyperintense basal ganglia in MRI. A further characterization of these subtypes is important for reliable diagnosis and identification of rare disease variants. The aim is to establish specific patterns of test results and clinical findings. These improvements in diagnostics may be the reason for the apparent increase in sCJD incidence in Germany from 0.9 in 1994 to 1.6 in a million in 2005. Despite careful surveillance, no patient with variant CJD has been detected to date in Germany. Here we present the data of the CJD surveillance of the last 13 years. Additionally, the improvements in diagnostics and differential diagnosis are discussed.  相似文献   

Molecular Modeling of the N-terminal Regions of High Molecular Weight Glutenin Subunits 7 and 5 in Relation to Intramolecular Disulfide Bond Formation     

Peter Khler  Bettina Keck-Gassenmeier  Herbert Wieser  Donald D. Kasarda 《Cereal Chemistry》1997,74(2):154-158

Analyses of cystine peptides derived from the high molecular weight glutenin subunits (HMW-GS) 5 and 7 indicate that, in spite of a distinct sequence homology between the two subunits in the N-terminal region, different disulfide linkages of cysteine residues are present in these regions. To investigate the structural basis for these experimental results, the conformational structures of the polypeptide chains corresponding to the N-terminal regions (first 50 amino acids) of the wheat HMW-GS 5 and 7 were modeled by computer methods. Secondary structures were predicted by the method of Rost and Sander (1993) and, to the extent appropriate, applied to the constructed polypeptide chains. The resulting structures were energy-minimized and subjected to simulated heating and dynamic equilibration. In the final structure of subunit 5, the first two cysteines were located in a region of continuous α-helix. If folding to the helical form occurs rapidly during biosynthesis as expected, the distance between the sulfhydryl groups of these two cysteines would be great enough (≈2.2 nm) to make intramolecular disulfide bond formation unlikely. Although a somewhat similar region of α-helix was predicted for the subunit 7, in some predictions the helix was interrupted between the first two cysteines, and this break was assigned either extended structure or arbitrarily modeled as an inverse γ-turn. In the final structure of subunit 7 with the assigned inverseγ-turn, after energy minimization, heating, and dynamics, the two cysteines approached one another closely (≈0.4 nm). Formation of an intramolecular disulfide bond appeared a likely possibility. This model is in accord with experimental evidence for this latter intramolecular bond (Köhler et al 1993). In agreement with the modeling, an equivalent intramolecular disulfide bond of subunit 5 has not been found and experimental evidence for a different arrangement is presented.  相似文献   

Rice roots and CH₄ oxidation: the activity of bacteria, their distribution and the microenvironment   总被引：9，自引：0，他引：9  

Bettina Gilbert  Peter Frenzel 《Soil biology & biochemistry》1998,30(14):1903-1916

Irrigated rice fields account for 10–30% of global methane emissions. Rice plants ventilate the soil and enlarge the oxic–anoxic interface by their root system, thus supplying the necessary O₂ to aerobic CH₄ oxidizing bacteria (MOB). Rice plants (Oryza sativa type japonica var. Roma) were grown in microcosms in a greenhouse. The roots were sandwiched between two blocks of flooded rice field soil separated by a nylon gauze bag. A root mat developed which mimicked the dense root texture in the upper layer of a natural rice field. Flux measurements under oxic and anoxic conditions showed that CH₄ was oxidized with a constant rate of 19% of the anoxically emitted CH₄, suggesting that CH₄ oxidation in the rhizosphere was at least sometimes limited by CH₄ availability. Washed rice roots could both produce and oxidize CH₄, depending upon incubation conditions. CH₄ production by washed rice roots accounted for at most 10% of the CH₄ emitted under anoxic conditions. Initial CH₄ oxidation rates of washed roots equaled oxidation rates calculated from the difference between oxic and anoxic fluxes in situ. Oxidation rates became twice as high after an induction period of 20 h, indicating a limitation by O₂ or CH₄ in situ. The micro-environmental conditions near to the root mat were measured using microelectrodes for O₂, redox potential and NH₄⁺ and diffusion probes for CH₄. Up to 42 μM O₂ was detected in the root mat and concentrations were >2.5 μM in 45% of all measurements. In the bulk soil, no O₂ was detected below 2 mm depth, but the root mat significantly increased the redox potential. Plant roots and associated bacteria decreased porewater CH₄ and NH₄⁺ concentrations. In the root mat, concentrations of dissolved CH₄ were below the detection limit of our probes (<5 μM). Cell numbers of MOB increased with time in the rhizosphere and in the rhizoplane. MOB and aerobic heterotrophic bacteria (AHB) each numbered from 10⁶ to 10⁸ cells g⁻¹ dry weight of soil or root biomass). Active MOB occurred near to a root mat similar to the dense root texture in the upper layer of rice fields. We speculate about O₂ or CH₄ limitation of MOB.  相似文献   

Toward pollen sterility in German chamomile (Matricaria chamomilla)–Conventional breeding approaches of cytoplasmic/genic male sterility and chemical emasculation     

Bettina Faehnrich  Julia Huber  Sarah Wagner  Chlodwig Franz  Beate Fraust  Maria Wehrle  Joana Ruzicka  Johannes Novak  Lars-Gernot Otto 《Plant Breeding》2020,139(6):1299-1309

Pollen sterility (PS) in mother lines is crucial for hybrid crossings in plant breeding. 21 di- (2x) and tetraploid (4x) accessions of the hermaphroditic chamomile were screened for spontaneous, thermic or gametocide induced PS. Two crossing trials with the diploid accessions 'Bona' (BON) and 'Hungary 2' (HUN2) should specify maternally inherited cytoplasmic male sterility (CMS). Progeny thereof showed increased PS. BON as mother (BH) entailed means of 30 and 22% PS, versus 8% and 20% after reciprocal crossings. Backcrosses of BH with HUN2 in paternal and maternal direction revealed increasing mean PS (24% and 32%), without verification of CMS. A split plot design of 100 individuals treated with four chemical gametocides analyzed PS, seed set, germination rate and whole plant damage. Tri-iodobenzoic acid caused the highest PS (43%). Progeny of two plants (2x, 4x) with degenerated anthers without pollen, showed 100% PS either in tetraploid F₁ and F₂ (4% and 11%) or in diploid F₂ and F₃ (26% and 23%). High temperature (30/28°C day/night) decreased the male fertility to some extent.  相似文献   

Occurrence of IgE in foals: evidence for transfer of maternal IgE by the colostrum and late onset of endogenous IgE production in the horse     

Wagner B  Flaminio JB  Hillegas J  Leibold W  Erb HN  Antczak DF 《Veterinary immunology and immunopathology》2006,110(3-4):269-278

IgE is the key antibody involved in type I allergies. Allergen mediated crosslinking of IgE bound to high affinity Fc-receptors on mast cells and basophils stimulates cellular degranulation and release of inflammatory mediators and cytokines. In this report, we demonstrate that IgE antibodies can be transferred from the mother to offspring in horses via the colostrum. We found a clear correlation between the IgE concentration in colostrum and the total IgE concentration in foal sera on day 2 after birth (r_sp = 0.83). Maternal IgE was detected in foal sera by ELISA and on peripheral blood leukocytes of foals by flow cytometry. Both serum and cell membrane-bound IgE were undetectable in newborn foals before colostrum uptake and peaked on days 2–5 after birth. Cell-bound IgE became undetectable at 2 months after birth. Serum IgE disappeared from the circulation within the first 3–4 months of age. These kinetics suggest that the IgE antibodies which are detectable in foals during the first 4 months after birth are of maternal origin only. The endogenous IgE production was found to begin at 9–11 months of age, when IgE could be detected on peripheral blood leukocytes and in foal sera again. After 18 months of life, the total IgE concentrations in foal sera were comparable to those detected in their dams. The late onset of endogenous IgE production offers an explanation for observations that IgE mediated allergies are generally not observed in horses before puberty. The roles of the passively transferred maternal IgE in newborn foals are not yet known, but could be manifold, ranging from passive immunity and induction of immunoregulatory functions to determinative influences of maternal IgE on the antibody repertoire in the offspring.  相似文献   

Use of a multivariable model to estimate the probability of discharge in hospitalized foals that are 7 days of age or less     

Rohrbach BW  Buchanan BR  Drake JM  Andrews FM  Bain FT  Byars DT  Bernard WV  Furr MO  Paradis MR  Lawler J  Giguère S  Dunkel B 《Journal of the American Veterinary Medical Association》2006,228(11):1748-1756

OBJECTIVE: To create a mathematical model to assist in early prediction of the probability of discharge in hospitalized foals < or= 7 days old. STUDY DESIGN: Prospective study. ANIMALS: 1,073 foals. PROCEDURES: Medical records from 910 hospitalized foals < or = 7 days old for which outcome was recorded as died or discharged alive were reviewed. Thirty-four variables including historical information, physical examination findings, and laboratory results were examined for association with survival. Variables associated with being discharged alive were entered into a multivariable logistic regression model. Accuracy of the model was validated prospectively on data from 163 foals. RESULTS: Factors in the final model included age group, ability to stand, presence of a suckle reflex, WBC count, serum creatinine concentration, and anion gap. Sensitivity and specificity of the model to predict live discharge were 92% and 74%, respectively, in the retrospective population and 90% and 46%, respectively, in the prospective population. Accuracy of an equine clinician's initial prediction of the foal being discharged alive was 83%, and accuracy of the model's prediction was 81%. Combining the clinician's prediction of probability of live discharge with that of the model significantly increased (median increase, 12%) the accuracy of the prediction for foals that were discharged and nonsignificantly decreased (median decrease, 9%) the accuracy of the predication for nonsurvivors. CONCLUSIONS AND CLINICAL RELEVANCE: Combining the clinician's initial predication of the probability of a foal being discharged alive with that of the model appeared to provide a more precise early estimate of the probability of live discharge for hospitalized foals.  相似文献   

IgE and IgG antibodies in skin allergy of the horse     

Wagner B  Miller WH  Morgan EE  Hillegas JM  Erb HN  Leibold W  Antczak DF 《Veterinary research》2006,37(6):813-825

In horses, allergies have been characterized by clinical signs and/or intradermal (i.d.) allergen testing. Our aim was to find the first direct evidence that immunoglobulin E (IgE) mediates equine allergy. In addition, we tested the hypothesis that immediate skin reactions in horses can also be mediated by IgG. Anti-IgE affinity columns were used to purify IgE from serum of one healthy horse and three horses affected with summer eczema, an allergic dermatitis which is believed to be induced by Culicoides midges. A modified Prausnitz-Küstner experiment was performed in four clinical healthy horses by i.d. injection of the purified serum IgE antibodies. The following day, Culicoides allergen was injected at the same sites. Skin reactions were not observed in response to allergen alone, and in two horses after stimulation at any previous IgE injection site. However, the other two horses showed an immediate skin reaction at the previous injection sites of IgE obtained from allergic horses. In addition, purified monoclonal antibodies to various equine immunoglobulin isotypes were injected i.d. into six healthy horses. Immediate skin reactions were observed in response to anti-IgE (6/6 horses) and anti-IgG(T) injections (5/6 horses). The specificities of both antibodies for IgE and IgG(T), respectively, were confirmed by enzyme linked immunosorbent assays. The results provide the first direct evidence that IgE mediates classical Type-I allergy in horses and plays a major role in the pathogenesis of summer eczema. The data also suggest that IgG(T) can bind to skin mast cells and might contribute to clinical allergy.  相似文献   

Variation and covariation for Gibberella ear rot resistance and agronomic traits in testcrosses of doubled haploid maize lines     

Matthias Martin  Wolfgang Schipprack  Thomas Miedaner  Baldev S. Dhillon  Bettina Kessel  Milena Ouzunova  Albrecht E. Melchinger 《Euphytica》2012,185(3):441-451

Gibberella ear rot (GER) of maize caused by Fusarium graminearum reduces grain yield and leads to contamination of the grains with deoxynivalenol (DON), a mycotoxin that adversely affects the health of humans and animals. The objectives of this study were to (1) analyze means and genotypic variances for line per se performance (LP) and testcross performance (TP) of doubled haploid (DH) lines for GER severity and DON concentration as well as for some agronomic traits, (2) examine correlations among these traits, (3) validate QTL for resistance detected in previous studies for LP and their effect on TP and (4) investigate the relative efficiency of indirect selection (RE) for LP to improve TP. Testcross progenies of 94 DH lines originating from four flint populations were developed using a susceptible dent tester as pollinator. Artificial inoculations with F. graminearum led to appreciable disease development. Average TP for GER severity and DON concentration were lower than the mean mid-parent values of the tester and DH lines, indicating mid-parent heterosis for resistance. Genotypic variation for resistance was significant for LP and TP. Genotypic correlations between LP and TP were low and resistance QTL for LP had no significant effects on TP. Accordingly, RE for resistance was low, suggesting to allocate resources mostly to the evaluation of testcrosses. Correlations of resistance to GER and DON contamination with grain yield (measured under non-inoculated conditions) were not significant, indicating that selection for resistance and higher grain yield can be carried out simultaneously.  相似文献