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1.
Eduardo Segundo Dietrich E. Lesemann Germán Martín María P. Carmona Leticia Ruiz Isabel M. Cuadrado Leonardo Velasco Dirk Janssen 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(1):81-87
Amaranthus leaf mottle virus (AmLMV) was classified as a member of the genus Potyvirus on the basis of its particle morphology, serology, and biological properties (Casetta et al., 1986). Based on these properties, an Amaranthus viridis-infecting virus isolated in Spain, causing mottle and leaf blistering as well as reduced growth has been identified as AmLMV.
The 3′ terminal genomic region of this and a reference isolate from Italy has been sequenced and reveals a 95% nucleotide
identity between the two isolates. The sequenced part comprises the coat protein with 281 amino acids and 315 nucleotides
of the 3′ untranslated region (UTR) preceding a polyadenylated tail. Pairwise comparisons and phylogenetic analysis of the
nucleotide and deduced amino acid sequences of the CP and 3′ UTR of the cloned cDNAs with those of other potyviruses shows
that AmLMV is a distinct potyvirus closely related to Potato virus Y. 相似文献
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3.
Giani M.B. Bohm Segundo Urquiaga Gustavo R. Xavier Cesar V. Rombaldi 《Soil biology & biochemistry》2009,41(2):420-422
Over half of the 21 Mha of soybean planted in Brazil is now transgenic glyphosate-resistant (GMRR). A field experiment was carried out to investigate whether the application of glyphosate or imazethapyr to the GMRR variety reduced the input of N2 fixation (BNF). No effects on yield, total N accumulation, nodulation and BNF (δ15N) could be assigned to the genetic modification of the plant. Imazethapyr reduced soybean yield but had no significant effect on BNF. Even though yields were not affected by glyphosate, the significant reduction of nodule mass and BNF to the GMRR suggests that the use of this herbicide could lead to an increased dependence on soil N and consequently an eventual decrease of SOM reserves. 相似文献
4.
ABSTRACT: Foot-and-mouth disease virus (FMVD), one of the most contagious viruses of cloven-hoofed animals, may cause a prolonged, asymptomatic but persistent infection in ruminants, named the "carrier state". However, it remains an open question whether this carrier state occurs in pigs. Here we present quantitative analyses of the duration of FMDV RNA and infectivity in lymphoid and epithelial tissues in experimentally infected pigs with FMDV C-S8c1. The data indicated that although FMDV RNA remained in blood until day 14 post-infection (pi), viremia was cleared by day 7 pi. However, all tissues tested were positive for FMDV until day 14-17 pi. Interestingly, the specific infectivity of FMDV in these tissues was in some cases even higher than the FMDV C-S8c1. We therefore propose that a "pseudopersistent state" may occur in pigs in which virus replicates in lymphoid tissues for a prolonged period of time, thereby representing a potential source of virus. 相似文献
5.
Oliveira HM Segundo MA Lima JL Grassi V Zagatto EA 《Journal of agricultural and food chemistry》2006,54(12):4136-4140
A sequential injection system for the automatic determination of glycerol in wine and beer was developed. The method is based on the rate of formation of NADH from the reaction of glycerol and NAD+ catalyzed by the enzyme glycerol dehydrogenase in solution. The determination of glycerol was performed between 0.3 and 3.0 mmol L(-1) (0.028 and 0.276 g L(-1)), and good repeatability was attained (rsd < 3.6%, n = 5) for all samples tested. The determination rate was 54 h(-1), the reagent consumption was only 0.75 micromol of NAD+ and 5.4 ng of enzyme per assay, and the waste production was 2.12 mL per assay. Results obtained for samples were in agreement with those obtained with the batch enzymatic method. 相似文献
6.
Eduardo Segundo María P. Carmona Elisa Sáez Leonardo Velasco Germán Martín Leticia Ruiz Dirk Janssen Isabel M. Cuadrado 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(4):579-591
A study was conducted to determine the identity and prevalence of viruses in 455 greenhouses in the main Spanish green bean
growing area. Directed surveys were conducted in 422 crops from 2000–2004 to collect samples from diseased plants displaying
symptoms that could be attributed to viruses. The samples were analysed to detect any virus by means of dsRNA extraction,
mechanical inoculation to test plants, as well as ELISA and/or RT-PCR tests to detect potyviruses, geminiviruses and viruses
previously known to infect beans in Spain. Random surveys were conducted in the years 2002 and 2005 (in 21 and 12 greenhouses,
respectively) to study the actual incidence of known viruses in the area. Symptoms were recorded in 23,108 plants from which
664 plants were collected and analysed by ELISA or RT-PCR. The results of the directed surveys showed that all the analyzed
crops carried the cryptic virus Phaseolus vulgaris endornavirus (PVuV), whereas phytopathogenic viruses appeared in smaller percentages of the crops: Tomato yellow leaf curl virus (TYLCV) 20.4%, Southern bean mosaic virus (SBMV) 9.0%, Tomato spotted wilt virus (TSWV) 4.0%, and the new species Bean yellow disorder virus (BnYDV) that broke out in 2004 with occurrence values higher than 34.3% that year. From 2000–2004 an important decrease in
TYLCV was observed, along with a slight increase in SBMV and a consistently low occurrence of TSWV. The results of the random
surveys confirmed the increased occurrence of virus detected during the directed surveys, and furthermore demonstrated the
percentage of incidence for each virus. 相似文献
7.
Cludia P. Jantalia Dimas V.S. Resck Bruno J.R. Alves Lincoln Zotarelli Segundo Urquiaga Robert M. Boddey 《Soil & Tillage Research》2007,95(1-2):97-109
A large area (180 Mha) of central Brazil is occupied by a savanna biome known as the Cerrado. Annual rainfall in this region varies from 1200 to 2000 mm, although there is a long (5 month) dry season with almost no rain. This region is regarded by Brazilians as their agricultural frontier and there is a steady growth in the area dedicated to permanent cropping in the region, which today is estimated to occupy 14 Mha. Owing to the dearth of long-term experiments, the impact of continuous cropping on soil carbon stocks remains unclear. The objective of this study was to evaluate the effects of different tillage systems (zero till (ZT) and conventional tillage (CT)) on the change in soil carbon stocks over a 20-year period of the same crop sequence compared to that under a neighbouring area of native vegetation (NV). Only approximately 10 Mg ha−1 of soil carbon in the 0–100 cm depth interval was lost under continuous ZT. However, under CT systems losses were greater (up to 30 Mg C ha−1) when the mouldboard plough was used and/or tillage was performed twice a year. We did not have access to instrumentation to accurately assess soil charcoal but the C/N data and peroxide and dichromate oxidative techniques suggested that 40% of soil C was in this form. The 13C natural abundance of soil profiles indicated that residues of crops (maize) and the spontaneous annual fallow of Brachiaria spp. resulted in integration of significant C4 residues to a depth of at least 40 cm. It would appear that zero tillage, which is already widely adopted in the Cerrado region of Brazil, will have only a small negative long-term impact on soil C stocks, but ploughing, especially more than once a year, will lead to considerably larger soil C losses. 相似文献
8.
I. Murillo L. Cavallarin B. San Segundo 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(3):301-311
The fungus Fusarium moniliforme infects a wide range of crops throughout the world. In maize (Zea mays L.) it causes seedling blight and root, stalk, and ear rots. A simple procedure that can be used to detect infection by F. moliliforme from infected plant tissues has been developed. A F. moniliforme genomic library was prepared and used to identify the recombinant clones containing fungal DNA sequences not hybridizing with the DNA of the host plant, maize. Based on the nucleotide sequence information obtained from the F. moniliforme pUCF2 genomic clone, specific oligonucleotides were designed and used as primers for in vitro DNA amplification by the polymerase chain reaction. An amplification product was obtained with F. moniliforme DNA preparations whereas no amplified DNA was detected with DNAs from other fungal pathogens, including various Fusarium species, or from the host plant. This PCR analysis was successfully employed to identify F. moniliforme directly from the mycelia that develop from naturally infected maize seeds, with no need to obtain pure fungal cultures for reliable diagnosis. The protocol can be used for the diagnosis of infected plants and soils in epidemiological studies of Fusarium diseases, for seed health testing, and for evaluation of susceptibility to colonization in commercial maize hybrids. 相似文献
9.
Francisco J Salguero Segundo Fayna Díaz-San Alejandro Brun María J Cano Juan M Torres 《Journal of veterinary diagnostic investigation》2006,18(1):106-109
Confirmatory diagnosis of prion diseases in humans and animals relies on the histopathological examination and immunodetection of the protease-resistant isoform of prion protein (PrPres). The generation of novel PrP-specific monoclonal antibodies (MAbs) has greatly improved diagnostic methodology and basic research on prion diseases as well. In this study, the performance of 3 different PrP-specific MAbs in recognizing brain PrPres deposits from cows affected with bovine spongiform encephalopathy (BSE) was compared by using a standard immunohistochemical technique under different pretreatment conditions. All antibodies showed similar reactivity after denaturing treatment. However, greater differences were found among them after proteinase K treatment, even in the absence of a denaturing step. In fact, 1 MAb (2A11) was able to react with PrPres deposits in the absence of a denaturing step, yielding the strongest signal and confirming the usefulness of MAb 2A11 in immunohistochemistry for the diagnosis of BSE. 相似文献
10.
Rice blast caused by the fungus Magnaporthe oryzae (anamorph Pyricularia grisea ) is one of the most devastating diseases of cultivated rice worldwide. In this study, a green fluorescent protein ( gfp )-expressing M. oryzae strain was generated and used to investigate the infection process in a commercial rice cultivar. Expression of the gfp gene did not affect the pathogenicity of the M. oryzae transformants. Confocal microscopy allowed in vivo imaging of this pathogen during infection of rice tissues. Magnaporthe oryzae pathogenicity was examined on both leaf and root tissues. In roots of wild-type plants, the fungus penetrated into epidermal and cortical cells, and colonized the central cylinder and xylem vessels. However, the dimorphic growth pattern typically observed during the biotrophic and necrotrophic stages of leaf colonization was not observed during colonization of root tissues. Furthermore, events occurring during infection of rice plants constitutively expressing the maize pathogenesis-related PRms gene were characterized and compared with those occurring during the interaction of this pathogen with untransformed rice plants. Fungal penetration was drastically reduced and delayed in tissues of PRms plants compared to untransformed plants. These results indicated that the gfp -expressing M. oryzae represents a strategic tool for the assessment of blast disease resistance in transgenic rice which can be also applied to the analysis of the M. oryzae interaction with other cultivars or mutants of important crop species. 相似文献