Surface temperature variability patterns within irrigated fields     

J.L. Hatfield  M. Vauclin  S.R. Vieira  R. Bernard 《Agricultural Water Management》1984,8(4):429-437

During 1981, an experiment was conducted to examine the spatial variability of surface temperature within differentially irrigated grain sorghum fields. The measurements were performed at the University of California-Davis in 85 m long transects measured with an infrared thermometer reading at 1.0 m intervals. These measurements were made repeatedly throughout the season. When the data were analyzed to evaluate the spatial variability along each transect, it was found that along the transects the readings at 1 m intervals were not correlated. This lack of structure or spatial dependence within a given field suggests that a random sampling in a field would be adequate for infrared thermometer measurements. During a drying cycle from one irrigation to the next, the variance of surface temperature along a transect increased. However, there was not a statistically significant relationship between the amount of water extracted from the upper 150 cm of the profile when more than 40% of the available water remained. When more than 60% of the available water had been removed, the variance increased above 0.5°C² but below this amount the variances did not exhibit any significant pattern. These data suggest that the variance of surface temperature within a field may not be a sensitive indicator of the soil water status. Utilizing the fact that the surface temperatures along the transects were random and normally distributed, we calculated that the number of samples needed to achieve a confidence limit of 1.0°C about the mean was 10 samples for a field with more than 40% available soil water and increased to 20 samples as the field dried below the 60% extraction level. These data suggest that the spatial variability techniques could be utilized to evaluate agricultural fields for their distribution efficiencies and problems. In application the samples required per field are a manageable number and could be analyzed with classical statistical methods.  相似文献   

Mitochondrial damage as an early event of monensin-induced cell injury in cultured fibroblasts L929     

Souza AC  Machado FS  Celes MR  Faria G  Rocha LB  Silva JS  Rossi MA 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2005,52(5):230-237

The present study was designed to identify, submicroscopically, the primary organelle or target structure for monensin in cultured murine fibroblasts L929. In addition, the effect of the drug on cell size and surface membranes of the cells were analysed; cellular proliferation, collagen secretion, and necrosis and apoptosis were re-evaluated. At the lowest concentration of monensin the foremost ultrastructural alteration occurred in the mitochondria, characterized by increased matrix density with disorganized and less distinct crystae. Incubation with monensin at higher concentrations resulted in severe mitochondrial damage and marked dilatation of the Golgi apparatus and rough endoplasmic reticulum cisternae. Fibroblasts exposed to higher concentrations of monensin were enlarged with decreased number of filopodia and hollows in the surface membrane. Moreover, monensin inhibited the cell proliferation, increased immunohistochemical positiveness for collagen type I in a dose-dependent manner, and, at high concentrations, caused cell necrosis whereas apoptosis was not induced. Taken together, these results show that monensin induces early mitochondrial damage, possibly causing an energy deficit that led to inhibition of fibroblasts proliferation and accumulation of collagen causing dilatation of Golgi apparatus and rough endoplasmic reticulum. Moreover, the mitochondrial damage would also explain the monensin-induced necrosis.  相似文献   

Serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) isolated from dairy cattle in São Paulo State, Brazil     

Irino K  Kato MA  Vaz TM  Ramos II  Souza MA  Cruz AS  Gomes TA  Vieira MA  Guth BE 《Veterinary microbiology》2005,105(1):29-36

In order to determine the occurrence, serotypes and virulence markers of Shiga toxin-producing Escherichia coli (STEC) strains, 153 fecal samples of cattle randomly selected from six dairy farms in Sao Paulo State, Brazil, were examined for Shiga toxin (Stx) production by the Vero cell assay. Feces were directly streaked onto MacConkey Sorbitol Agar and incubated at 37 degrees C overnight. Sorbitol-negative colonies (maximum 20) and up to 10 sorbitol-positive colonies from each plate were subcultured onto presumptive diagnostic medium IAL. Sorbitol-negative isolates were screened with O157 antiserum for identification of O157:H7 E. coli. Isolates presenting cytotoxic activity were submitted to colony hybridization assays with specific DNA probes for stx1, stx2, eae, Ehly and astA genes. The isolation rate of STEC ranged from 3.8 to 84.6% depending on the farm analysed. STEC was identified in 25.5% of the animals, and most of them (64.1%) carried a single STEC serotype. A total of 202 STEC isolates were recovered from the animals, and except for the 2 O157:H7 isolates all the others expressed cytotoxic activity. The great majority of the STEC isolates carried both stx1 and stx2 genes (114/202, 56.4%) or stx2 (82/202, 40.6%); and whereas the Ehly sequence occurred in most of them (88%) eae was only observed in O157:H7 and O111:HNM isolates. Serotypes O113:H21, O178:H19 and O79:H14 were the most frequent STEC serotypes identified and widely distributed among animals from different farms, while others such as O77:H18, O88:H25 and O98:H17 occurred only in particular farms. This is the first report on the occurrence of STEC in dairy cattle in Sao Paulo State, and the results point to substantial differences in rate of isolation, serotypes and genetic profile of STEC that has been previously described among beef cattle in our community. Moreover, to our knowledge O79:H14 and O98:H17 represent new STEC serotypes, while O178:H19 has only been recently reported in Spain.  相似文献   

Seroprevalence of Toxoplasma gondii in wild pigs (Sus scrofa) from Spain     

Gauss CB  Dubey JP  Vidal D  Ruiz F  Vicente J  Marco I  Lavin S  Gortazar C  Almería S 《Veterinary parasitology》2005,131(1-2):151-156

Sera collected from 507 hunter-killed wild pigs (Sus scrofa) between 1993 and 2004 from five geographic regions in northern Spain and seven regions in southern Spain were assayed for antibodies to Toxoplasma gondii by the modified agglutination test (MAT). Antibodies to T. gondii were detected in 185 (38.4%) of 507 pigs with titers of 1:25 in 71, 1:50 in 111 and > or =1:500 in 3; seroprevalence was significantly higher (P<0.05) in pigs from southern regions. Seroprevalence was density dependent; it was higher in pigs from high stocking per hectare and availability of forage. Statistically significant differences were not observed between T. gondii seroprevalence and hunting estates (open versus fenced), sex or age. Serological results indicate a widespread exposure to T. gondii among Spanish wild boars, suggesting that this population could represent a public health risk for persons that handle or consume raw or undercooked infected wild pig meat.  相似文献   

Anaplasma infection in free-ranging Iberian red deer in the region of Castilla-La Mancha, Spain   总被引：4，自引：0，他引：4  

De La Fuente J  Vicente J  Höfle U  Ruiz-Fons F  Fernández De Mera IG  Van Den Bussche RA  Kocan KM  Gortazar C 《Veterinary microbiology》2004,100(3-4):163-173

Organisms in the genus Anaplasma are obligate intracellular pathogens that multiply in both vertebrate and invertebrate hosts. The type species, Anaplasma marginale, causes bovine anaplasmosis and infects erythrocytes of the vertebrate host and undergoes a complex developmental cycle in ticks which serve as biological vectors. Infected cattle, wild ruminants and ticks can all serve as reservoirs of A. marginale. In this study, hunter killed Iberian red deer (Cervus elaphus hispanicus) from the region of Castilla-La Mancha in southwestern Spain were tested for Anaplasma infection. We found that 10% of the deer examined were seropositive for Anaplasma. Three A. marginale strains were subsequently obtained from salivary glands of Hyalomma marginatum that were removed from these deer, and the sequence of the major surface protein (msp)4 gene was determined for each strain and used for phylogenetic studies. Maximum parsimony analyses of msp4 sequences from H. marginatum ticks in comparison with New World cattle and bison isolates reported previously, suggested different origins for these Spanish A. marginale strains. The results of this study demonstrated that Iberian red deer are naturally infected with Anaplasma, and may therefore serve as a wildlife reservoir of the pathogen. Although the link between deer infection and the strains of A. marginale identified in ticks was not established, H. marginatum and Rhipicephalus bursa were identified as potential biological vectors for A. marginale in this region and may effect transmission of A. marginale between deer and cattle populations.  相似文献   

Diversity of Paenibacillus durus strains isolated from soil and different plant rhizospheres evaluated by ARDRA and gyrB-RFLP analysis     

Julia Peixoto de Albuquerque  Fabio Faria da Mota  Irene von der Weid  Lucy Seldin   《European Journal of Soil Biology》2006,42(4):200-207

Strains belonging to Paenibacillus durus isolated from the rhizosphere of various grasses and from bulk soil were previously divided into five phenotypic groups (A1–A5) based on the fermentation pattern of six carbohydrates (A1: sorbitol (+), A2: dulcitol and tagatose (+), A3: starch and glycogen (+), A4: starch, glycogen and d-arabitol (+) and A5: negative for these carbohydrates). This study aimed to assess whether plant types select for specific P. durus phenotypic groups. For that purpose, polymerase chain reaction-restriction fragment length polymorphism analysis of part of genes encoding 16S rRNA (ARDRA) and DNA gyrase subunit B (gyrB-RFLP) were used to produce genetic fingerprints. ARDRA and gyrB-RFLP data were clustered together to generate a dendrogram and two main clusters were observed. Cluster I showed a predominance of strains isolated from wheat, maize and sugarcane rhizospheres. Strains isolated from maize were distributed among the five patterns of carbohydrate metabolism, while strains isolated from sugarcane showed to be predominantly able to metabolize starch and glycogen. Neither sorbitol- nor arabitol-metabolizing strains were found in cluster II, which consisted of strains isolated from soil and from all plant species used. Our results suggest that the plants influenced the diversity of P. durus in their rhizospheres.  相似文献   

An immunocytochemical procedure for protein localization in various nematode life stages combined with plant tissues using methylacrylate-embedded specimens     

Vieira P  Banora MY  Castagnone-Sereno P  Rosso MN  Engler G  de Almeida Engler J 《Phytopathology》2012,102(10):990-996

Plant-parasitic nematodes possess a large number of proteins that are secreted in planta, allowing them to be successful parasites of plants. The majority of these proteins are synthesized mainly in the nematode subventral and dorsal glands as well as in other organs. To improve the immunovisualization of these proteins, we adapted a methacrylate embedding method for the localization of proteins inside nematode tissues, and extracellularly when secreted in planta or within plant cells. An important advantage is that the method is applicable for all nematode stages: preparasitic as well as parasitic stages, including large mature females. Herein, the method has been successfully applied for the localization of four nematode secreted proteins, such as Mi-MAP-1, Mi-CBM2-bearing proteins, Mi-PEL3, and Mi-6D4. In addition, we could also localize 14-3-3 proteins, as well as two cytoskeletal proteins, by double-immunolabeling on preparasitic juveniles. Superior preservation of nematode and plant morphology, allowed more accurate protein localization as compared with other methods. Besides excellent epitope preservation, dissolution of methacrylate from tissue sections unmasks target proteins and thereby drastically increases antibody access.  相似文献   

Development of molecular markers based on retrotransposons for the analysis of genetic variability in Moniliophthora perniciosa     

Mateus Ferreira Santana  Elza Fernandes de Araújo  Jorge Teodoro de Souza  Eduardo Seiti Gomide Mizubuti  Marisa Vieira de Queiroz 《European journal of plant pathology / European Foundation for Plant Pathology》2012,134(3):497-507

Moniliophthora perniciosa is a fungus that causes witches?? broom disease (WBD) in the cacao tree (Theobroma cacao). The M. perniciosa genome contains different transposable elements; this prompted an evaluation of the use of its retrotransposons as molecular markers for population studies. The inter-retrotransposon amplified polymorphism (IRAP) and retrotransposon-microsatellite amplified polymorphism (REMAP) techniques were used to study the variability of 70?M. perniciosa isolates from different geographic origins and biotypes. A total of 43 loci was amplified. Cluster analysis of different geographical regions of C biotype revealed two large groups in the state of Bahia, Brazil. Techniques using retrotransposon-based molecular markers showed advantages over previously used molecular techniques for the study of genetic variability in M. perniciosa.  相似文献   

Expression profiling of genes involved in the biotrophic colonisation of Coffea arabica leaves by Hemileia vastatrix     

Ana Vieira  Pedro Talhinhas  Andreia Loureiro  Johannes Thürich  Sébastien Duplessis  Diana Fernandez  Maria do Céu Silva  Octávio S. Paulo  Helena Gil Azinheira 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(1):261-277

  相似文献   

Urinary glycosaminoglycans in horse osteoarthritis. Effects of chondroitin sulfate and glucosamine     

Baccarin RY  Machado TS  Lopes-Moraes AP  Vieira FA  Michelacci YM 《Research in veterinary science》2012,93(1):88-96

Our objectives were to characterize the urinary excretion of glycosaminoglycans (GAGs) in horse osteoarthritis, and to investigate the effects of chondroitin sulfate (CS) and glucosamine (GlcN) upon the disease. Urinary GAGs were measured in 47 athletic horses, 20 healthy and 27 with osteoarthritis. The effects of CS and GlcN were investigated in mild osteoarthritis. In comparison to normal, urinary GAGs were increased in osteoarthritis, including mild osteoarthritis affecting only one joint. Treatment with CS+GlcN led to a long lasting increase in the urinary CS and keratan sulfate (KS), and significant improvement in flexion test of tarsocrural and metacarpophalangeal joints was observed. In conclusion, urinary CS and KS seems to reflect the turnover rates of cartilage matrix proteoglycans, and the measurement of these compounds could provide objective means of evaluating and monitoring joint diseases.  相似文献