排序方式： 共有22条查询结果，搜索用时 468 毫秒
1.
Feberwee A Dijkstra JR von Banniseht-Wysmuller TE Gielkens AL Wagenaar JA 《Veterinary microbiology》2005,111(1-2):125-131
Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the cause of considerable economic losses in the poultry industry. Molecular differentiation of avian Mycoplasma strains may be helpful in tracing infections and in the evaluation of implemented intervention strategies. Amplified Fragment Length Polymorphism (AFLP) has shown to be a powerful typing technique but the application for poultry Mycoplasma strains is very limited. The aim of this study was to evaluate the reproducibility and discriminatory power of AFLP HindIII/HhaI and AFLP BglII/Mfel for the inter- and intraspecies differentiation of avian mycoplasmas and to compare these test characteristics with digitalized Random Amplified Polymorphic DNA (RAPD) analysis. The reproducibility of RAPD, AFLP HindIII/HhaI and AFLP BglII/Mfel was 50-100, 97-98 and 86-99%, respectively. RAPD and both AFLP enzyme combinations were able to differentiate between five avian Mycoplasma species. For AFLP, five MG and four MS clusters could be identified. The phylogenetic tree for both enzyme combinations was comparable. For RAPD, four MG clusters could be identified. For MS, however, due to the poor reproducibility of the RAPD technique, no clear genogroups could be identified. On basis of the results of this study it can be concluded that AFLP is a powerful technique for the genotyping of avian mycoplasmas and that, although AFLP HindIII/HhaI generated patterns with less fragments, the final results showed homologous results. 相似文献
2.
Casparus J. BRINK Anneke POSTMA Etienne SLABBERT Ferdinand POSTMA A. Muthama MUASYA Karin JACOBS 《土壤圈》2020,30(6):778-790
Aspalathus linearis is a commercially important plant species endemic to the Cape Floristic Region of South Africa and is used to produce a herbal tea known as rooibos tea. Symbiotic interactions between A. linearis and soil bacteria play an important role in the survival of Aspalathus plants in the highly nutrient-poor, acidic fynbos soil. The aim of this study was to characterize and compare rhizosphere and bulk soil bacterial communities associated with natural and commercially grown A. linearis, as well as the effect of seasonal changes on these communities. Bacterial communities were characterized using high throughput amplicon sequencing, and their correlations with soil chemical properties were investigated. The N-fixing bacterial community was characterized using terminal restriction fragment length polymorphism and real time quantitative polymerase chain reaction. Actinobacteria, Proteobacteria, and Acidobacteria were the most dominant bacterial phyla detected in this study. Highly similar bacterial communities were associated with natural and commercially grown plants. Significant differences in the bacterial community were observed between rhizosphere and bulk soils collected in the dry season, while no significant differences were detected in the wet season. This study provides insights into bacterial community structure and potential factors shaping bacterial community structure with commercially important A. linearis. 相似文献
3.
Sri Rejeki Adolphe O. Debrot Anneke M. van den Brink Restiana W. Ariyati Lestari Lakshmi Widowati 《Aquaculture Research》2021,52(1):373-380
The effectiveness of green mussel (Perna viridis) cultivation was compared between longline culture and the traditional bamboo stake method using different mussel densities in a rural area on the north coast of Java, Indonesia. The study took place in a rural area about 2 km north‐east from the city of Semarang where unsustainable shrimp and fish pond culture in the past has led to massive mangrove loss, spiralling environmental degradation and socio‐economic disintegration. Mangrove‐friendly alternatives for a sustainable socio‐economic recovery of local livelihoods are urgently being sought. Longlines were more successful than the stake method in spat collection. Longlines also showed a small but significantly higher relative weight gain and specific growth rate for mussels than bamboo stakes. Mussels in lower densities showed higher survival and grew to larger individual sizes, but initial seeding density had no significant effect on relative weight gain or specific growth rate per stocking. Slightly lower set‐up costs and time investment and somewhat higher yields for longlines give an almost twofold higher income per time unit of own time invested by the farmer for longline culture over the traditional stake culture method. The profitability of mussel culture using the stake method is below the average hourly wage for skilled labour, but above that when using the longline method. We conclude that green mussel culture using the longline system is feasible as an alternative to less sustainable forms of livelihood for the local communities in mangrove areas. 相似文献
4.
Resistance to western flower thrips in greenhouse cucumber: effect of leaf position and plant age on thrips reproduction 总被引：1，自引：0，他引：1
Willem Jan de Kogel Anneke Balkema-Boomstra Marieke van der Hoek Sierd Zijlstra Chris Mollema 《Euphytica》1997,94(1):63-67
Three greenhouse cucumber (Cucumis sativus L.) accessions, previously selected for low levels of damage after infestation
with Frankliniella occidentalis (Pergande), were tested for resistance against F. occidentalis in a no-choice greenhouse experiment
at the mature plant stage. The three accessions showed a strong reduction in thrips damage compared to the susceptible control.
The effects of leaf position and plant age of the four cucumber accessions on the reproduction of F. occidentalis were determined
in a leaf disc assay. Leaf position had a significant effect on thrips reproduction, whereas plant age, within the test range,
had not. In general, reproduction was higher on young leaves. Reproduction as measured on leaf discs from certain leaf positions
was strongly correlated with resistance of mature plants in the greenhouse, and can therefore be used as a quick test to screen
cucumber accessions for resistance against thrips.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Jeana Pereira da Silva Sheila Canevese Rahal Maria Cristina Reis Castiglioni Raphael Augusto Baldissera Gonçalves Danuta Pulz Doiche Anneke Moresco Maria Jaqueline Mamprim Luiz Carlos Vulcano 《Anatomia, histologia, embryologia》2020,49(4):541-549
This study aimed to evaluate normal features of the heart and lower respiratory tract in toco toucans by means of radiography and helical computed tomography (CT) scanner. Fifteen healthy adult toco toucans (Ramphastos toco), 10 females and 5 males, average body mass of 650 g were studied. CT examination as well as right lateral and ventrodorsal radiographic examinations of the coelomic cavity were performed under chemical restraint. Heart, lungs, air sacs, trachea and syrinx were analysed. The mean values of heart length, heart width and thoracic cavity in radiographs were, respectively, 23.76 mm, 25.94 mm and 48.87 mm. In both X-rays and CT scans, the lung parenchyma had honeycomb-like pattern. The topographic areas of the anterior and posterior air sacs were visualized as dark and air-filled spaces in X-rays. On CT evaluation, the air sacs occupied a larger area in the coelomic cavity compared to X-ray. In the lateral radiographic view, the cervical part of the trachea was positioned more ventrally in the transition from cervical to thoracic regions showing a V-shaped appearance. In all CT planes was visible division of the trachea into the right and left main bronchi at the level of 3rd thoracic vertebra. The syrinx was difficult to visualize in X-rays, but on CT it was easily identified in axial slice. In conclusion, the normal features of toco toucan's heart and lower respiratory tract that were determined on X-rays and CT scans are useful to compare with sick toco toucans, as well as other bird species. 相似文献
6.
Nitrogen acquisition,fixation and transfer in maize/alfalfa intercrops are increased through root contact and morphological responses to interspecies competition 
下载免费PDF全文
下载免费PDF全文 Ze-qiang SHAO Cong-cong ZHENG Johannes A. POSTMA Wen-long LU Qiang GAO Ying-zhi GAO Jin-jing ZHANG 《农业科学学报》2021,20(8):2240-2254
Nitrogen(N) fixation by legumes and nitrogen transfer to cereals have been considered as important pathways for overyielding and higher N use efficiency in cereal/legume intercropping systems. However, the extent to which root morphology contributes to N fixation and transfer is unclear. A two-factorial greenhouse experiment was conducted to quantify the N fixation, transfer and root morphology characteristics of the maize/alfalfa intercropping system in two consecutive years using the 15 N-urea leaf labeling method, and combining two N levels with three root separation techniques. N application could inhibit N fixation and transfer in a maize/alfalfa intercropping system. Irrespective of the N application level, compared with plastic sheet separation(PSS), no separation(NS) and nylon mesh separation(NNS) significantly increased the total biomass(36%) and total N content(28%), while the N fixation rate also sharply increased by 75 to 134%, and the amount of N transferred with no root barrier was 1.24–1.42 times greater than that with a mesh barrier. Redundancy analysis(RDA) showed that the crown root dry weight(CRDW) of maize and lateral root number(LRN) of alfalfa showed the strongest associations with N fixation and transfer. Our results highlight the importance of root contact for the enhancement of N fixation and transfer via changes in root morphology in maize/alfalfa intercropping systems, and the overyielding system was achieved via increases in maize growth, at the cost of smaller decreases in alfalfa biomass production. 相似文献
7.
Dawid C Henze A Frank O Glabasnia A Rupp M Büning K Orlikowski D Bader M Hofmann T 《Journal of agricultural and food chemistry》2012,60(11):2884-2895
To gain a more comprehensive knowledge on whether, besides the well-known piperine, other compounds are responsible for the pungent and tingling oral impression imparted by black pepper, an ethanol extract prepared from black pepper (Piper nigrum L.) was screened for its key sensory-active nonvolatiles by application of taste dilution analysis (TDA). Purification of the compounds perceived with the highest sensory impact, followed by LC-MS and 1D/2D NMR experiments as well as synthesis, led to the structure determination of 25 key pungent and tingling phytochemicals, among which the eight amides 1-(octadeca-2E,4E,13Z-trienyl)piperidine, 1-(octadeca-2E,4E,13Z-trienyl)pyrrolidine, (2E,4E,13Z)-N-isobutyl-octadeca-2,4,13-trienamide, 1-(octadeca-2E,4E,12Z-trienoyl)-pyrrolidine, 1-(eicosa-2E,4E,15Z-trienyl)piperidine, 1-(eicosa-2E,4E,15Z-trienyl)pyrrolidine, (2E,4E,15Z)-N-isobutyl-eicosa-2,4,15-trienamide, and 1-(eicosa-2E,4E,14Z-trienoyl)-pyrrolidine were not yet reported in literature. Sensory studies by means of a modified half-tongue test revealed recognition thresholds ranging from 3.0 to 1150.2 nmol/cm2 for pungency and from 520.6 to 2162.1 nmol/cm2 for the tingling orosensation depending on their chemical structure. 相似文献
8.
Rachael K. Lau Anneke Moresco Sarah J. Woods Christopher M. Reilly Michelle G. Hawkins Christopher J. Murphy Steven R. Hollingsworth Dennis Hacker Kate S. Freeman 《Veterinary ophthalmology》2017,20(6):560-567
A juvenile to young adult, male, great horned owl (Bubo virginianus,GHOW) was presented to the wildlife rehabilitation hospital at Lindsay Wildlife Museum (WRHLWM) due to trauma to the right patagium from barbed wire entanglement. On presentation, both corneas were irregular, dry, and no movement of the third eyelid was noted. A severe corneal enlargement/globoid appearance was the predominant ophthalmic feature. The fundus was normal in both eyes (OU). Over the course of several days, both corneas developed edema combined with further dessication at the ocular surface associated with diffuse dorsal fluorescein stain uptake. Repeated ophthalmic examinations found normal intraocular pressures and an inability to move the third eyelid over the enlarged corneas. The bird was deemed nonreleasable due to severe wing damage and poor prognosis associated with eye abnormalities and was humanely euthanized. Postmortem CT, enucleation, and histopathology were performed to evaluate the ocular anatomical abnormality and confirm the suspected diagnosis of keratoglobus. This GHOW represents the first reported case of presumptive keratoglobus in a raptor. 相似文献
9.
Broersen K Van Teeffelen AM Vries A Voragen AG Hamer RJ De Jongh HH 《Journal of agricultural and food chemistry》2006,54(14):5166-5174
The aim of this work is to evaluate the impact of sulfhydryl groups on ovalbumin aggregation and gelation. Ovalbumin was chemically modified to add sulfhydryl groups in various degrees. The rate of aggregation was not affected by the introduction of sulfhydryl groups, and disulfide bond formation was preceded by physical interactions. Hence, disulfide interactions may not be the driving force for the aggregation of ovalbumin. Investigation of the aggregates and gels by electron microscopy and rheology suggested that a critical number of sulfhydryl groups can be introduced beyond which the microstructure of the aggregates transforms from fibrillar into amorphous. Rheological studies further suggested that covalent networks, once formed, do not have the possibility to rearrange, reducing the possibility to attain a stronger network. These results show that, even though aggregation of ovalbumin may be primarily driven by physical interactions, formed disulfide bonds are important to determine the resulting aggregate morphology and rheological properties. 相似文献
10.
A green-fleshed cucumber mosaic virus (CMV)-resistant cantaloupe line, ‘Xy 140’, resembling the recurrent parent, was obtained after five cycles of backcrossing followed by selfing from a cross between the cultivars ‘Noy Yizre’el’ (susceptible) and ‘Freeman Cucumber’ (resistant). Compared with the respective non-infected cultivars, CMV infection in an early stage of growth reduced the yield of Noy Yizre’el by 73% and of Xvl40 by 31%. Yield reduction in Noy Yizre’el was due to fewer fruits and lower fruit weight, whereas in Xvl40 fruit weight was not affected although the number of fruits per plant was reduced. CMV content of Xvl40 was much lower than that of Noy Yizre’el, but slightly higher than that of the resistant parent — Freeman Cucumber. These results may indicate that during the breeding process a slight loss in the level of resistance had occurred. For all practical purposes, Xvl40 possesses a high level of resistance which will enable good commercial yields even under conditions of very early CMV infection. 相似文献