Regulation of cell polarity and protrusion formation by targeting RhoA for degradation     

Wang HR  Zhang Y  Ozdamar B  Ogunjimi AA  Alexandrova E  Thomsen GH  Wrana JL 《Science (New York, N.Y.)》2003,302(5651):1775-1779

The Rho family of small guanosine triphosphatases regulates actin cytoskeleton dynamics that underlie cellular functions such as cell shape changes, migration, and polarity. We found that Smurf1, a HECT domain E3 ubiquitin ligase, regulated cell polarity and protrusive activity and was required to maintain the transformed morphology and motility of a tumor cell. Atypical protein kinase C zeta (PKCzeta), an effector of the Cdc42/Rac1-PAR6 polarity complex, recruited Smurf1 to cellular protrusions, where it controlled the local level of RhoA. Smurf1 thus links the polarity complex to degradation of RhoA in lamellipodia and filopodia to prevent RhoA signaling during dynamic membrane movements.  相似文献   

The interaction of the atmosphere of Enceladus with Saturn's plasma     

Tokar RL  Johnson RE  Hill TW  Pontius DH  Kurth WS  Crary FJ  Young DT  Thomsen MF  Reisenfeld DB  Coates AJ  Lewis GR  Sittler EC  Gurnett DA 《Science (New York, N.Y.)》2006,311(5766):1409-1412

During the 14 July 2005 encounter of Cassini with Enceladus, the Cassini Plasma Spectrometer measured strong deflections in the corotating ion flow, commencing at least 27 Enceladus radii (27 x 252.1 kilometers) from Enceladus. The Cassini Radio and Plasma Wave Science instrument inferred little plasma density increase near Enceladus. These data are consistent with ion formation via charge exchange and pickup by Saturn's magnetic field. The charge exchange occurs between neutrals in the Enceladus atmosphere and corotating ions in Saturn's inner magnetosphere. Pickup ions are observed near Enceladus, and a total mass loading rate of about 100 kilograms per second (3 x 10(27) H(2)O molecules per second) is inferred.  相似文献   

Factors affecting colostrum quality in Australian pasture‐based dairy herds          下载免费PDF全文

GM Chuck  PD Mansell  MA Stevenson  MM Izzo 《Australian veterinary journal》2017,95(11):421-426

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Volume estimation of Cryptomeria japonica logs in southern Brazil using artificial intelligence models   总被引：1，自引：0，他引：1  

Carlos R Sanquetta  Luani RO Piva  Jaime Wojciechowski  Ana PD Corte 《Southern Forests》2018,80(1):29-36

This study aimed to test taper functions and artificial intelligence (AI) models in order to estimate merchantable volumes of Japanese cedar (Cryptomeria japonica) trees in a homogenous plantation in southern Brazil. A total of 30 individuals were rigorously scaled and their total volumes were calculated, including those of the following log assortments: veneer, sawn, pulp and energy. Three AI models, i.e. two variants of k-nearest neighbours (KNN) instance-based classification (one and three nearest neighbours) and an artificial neural network (ANN) approach, were compared with three traditional taper models: fifth-order polynomial, fractional powers and the Garay model. The estimated volumes were compared with the actual volumes by means of the standard error (S_yx), bias, precision and accuracy. Total volume estimates proved to be unbiased (maximum bias 5.42%), precise (maximum precision 9.28%) and accurate (maximum accuracy 10.79%) with all of the investigated models. The tested models tended to give lower bias, better precision and accuracy in the middle portion of the stems, but worse estimates at the base and tip (maximum bias ?12.41%). In general, the KNN models improved merchantable volume estimation, particularly KNN1, which is a straightforward and simple method. We conclude that AI techniques have appeal for application in forest inventories and that KNN is a particularly interesting alternative for tree volume estimation.  相似文献   

Geographic distribution and disease severity of different Rhizoctonia species pathogenic towards maize in different regions in Germany and France     

Thomsen  G.  Birr  T.  Klink  H.  Verreet  J.-A. 《植物病害和植物保护杂志》2018,125(5):461-468

Journal of Plant Diseases and Protection - The geographic distribution and DNA-disease severity of the anastomosis groups (AG) 1 IA, AG 1 IB and AG 2-2 IIIB within the teleomorph Thanatephorus...  相似文献   

TRANSCUTANEOUS ULTRASONOGRAPHY OF THE AVIAN UROGENITAL TRACT     

Helmut  Hofbauer  DVM  Dr.med.vet.  Maria-E.  Krautwald-Junghanns  DVM Dr.med.vet. Dr.med.vet. habil.  PD 《Veterinary radiology & ultrasound》1999,40(1):58-64

The purpose of this article is to provide a survey of the diagnostic use of transcutaneous sonographic examination of the urogenital tract of pet birds. Possibilities and limitations in imaging normal and altered components of this organ system are discussed. Ultrasonographic examination of the avian urogenital tract was evaluated in 386 pet birds. Abnormal clinical signs were present in 289 birds; 97 birds were normal. Transcutaneous ultrasonography proved to be a useful, noninvasive, and fast diagnostic tool, especially in imaging laminated eggs and changes of the oviduct. Until now, these pathologic changes were not diagnosable in birds with other common noninvasive methods (e.g. radiography). The imaging of low-grade changes of the oviduct, disorders of the kidney without enlargement of the organ, as well as roughening of the egg shell proved to be difficult. Sonographic imaging of neither the normal kidney nor the inactive gonads was possible.  相似文献   

Atlantic salmon fed a nutrient package of surplus methionine,vitamin B12, folic acid and vitamin B6 improved growth and reduced the relative liver size,but when in excess growth reduced     

Marit Espe  Vibeke Vikes  Trn Helgy Thomsen  Anne‐Catrin Adam  Takaya Saito  Kaja H. Skjrven 《Aquaculture Nutrition》2020,26(2):477-489

Feeding plant‐based diet through smoltification of Atlantic salmon requires verification of the optimal level of 1C nutrients. Here, we fed Atlantic salmon plant‐based diets containing three different surplus amounts of the 1C nutrients; methionine, cobalamin (vitamin B12), pyridoxine (vitamin B6) and folic acid during 6 weeks in fresh water, through smoltification, followed by 3 months on‐growing period in salt water. The three diets were fed to fish dispersed in triplicate tanks throughout the experiment. Mean start body weight was 32 g. Dietary methionine levels in the diets were 6.7, 9.2 and 11.7 g/kg. Dietary B6 was 6.75, 8.45 and 11 mg/kg. Cobalamin was 0.16, 0.18 and 0.20 mg/kg. While dietary folic acid was 2.9, 4.8 and 6.3 mg/kg, diets are referred to as low, medium and high 1C diet. All other amino acids were similar between diets. The results showed no differences in growth or feed utilization in the fresh water period, but following the on‐growing salt water period, differences between diets occurred. The fish fed the medium 1C diet showed better growth, as compared to fish fed the low or high 1C diet (p = .009). The medium 1C fed fish showed a relative lower liver weight compared with fish fed low or high 1C diet (p = .025). Condition factor was better in fish fed the medium and high 1C diet as compared to those fed the low 1C diet (p = .0006). As expected, free methionine in liver, plasma and muscle increased by dietary methionine inclusion. Surplus vitamins only had minor effect on tissue concentrations. Based on these findings, we conclude that the micronutrient and methionine level presented in the medium 1C diet improved the growth, liver size and condition factor; however, more research is needed to evaluate the optimal requirement level for each of the 1C nutrients.  相似文献   

Soil organic matter decline and compositional change associated with cereal cropping in southern Tanzania     

J. F. McDonagh  T. Birch Thomsen  J. Magid 《Land Degradation \u0026amp; Development》2001,12(1):13-26

The spatial analogue method and ¹³C analytical techniques were used to reveal medium‐ to long‐term changes in soil organic matter (SOM) in farmers' fields under maize in southern Tanzania. Aerial photography and detailed farmer interviews were used to relate land‐use history to declines in SOM concentration and changes in composition. The research attempted to measure the rate of SOM decline and the extent to which farmers' residue management practice was allowing cereal residues to contribute to SOM. The combination of research methods employed in this study proved to be highly complementary. Results indicate that native SOM decreased by on average 50 per cent; after 25 years of cultivation. Under current residue management with cereal residues mostly grazed and burnt there is only a relatively modest contribution from cereal residues to SOM. When cereal residues are retained in the field it is likely they will contribute significantly to SOM but they are much less likely to build SOM in the medium to long term. The paper concludes that in many situations it is probably best for farmers to allow the majority of the residues to be eaten by cattle in these systems rather than attempt to build SOM or risk nitrogen immobilization in cropped fields. The greater importance of inputs of high‐quality (e.g. legume) residues for nutrient supply in the short term is highlighted, in contrast to inputs of poor‐quality (e.g. cereal) residues in an attempt to build SOM in the longer term. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献