Serological and molecular evidence of hepatitis E virus in swine in Brazil     

dos Santos DR  Vitral CL  de Paula VS  Marchevsky RS  Lopes JF  Gaspar AM  Saddi TM  Júnior NC  Guimarães Fde R  Júnior JG  Ximenes LL  Souto FJ  Pinto MA 《Veterinary journal (London, England : 1997)》2009,182(3):474-480

Active hepatitis E virus (HEV) infections in two Brazilian swine herds were investigated. In study 1, 26 piglets born to five anti-HEV positive sows were monitored from birth to post-partum week 22. Serum samples were screened for the detection of anti-HEV antibodies and a nested RT-PCR used to examine the HEV genome. Passive transfer of immunity was confirmed. At week 22, 23/26 (88.4%) of the piglets had seroconverted. Genome amplification was achieved in a feces pool from one holding pen and in one serum sample, both from 13-week-old animals. Histology was suggestive of a potential HEV infection. In the second study, 47 piglets born to six anti-HEV-positive sows were monitored after weaning. Seroconversion was determined in eight animals at 6-8 weeks of age. HEV RNA was detected in two pools from a holding pen for 12-16-week-old animals. Brazilian isolates were classified as genotype 3. This is the first molecular evidence of HEV infection in Brazilian pig herds.  相似文献   

Prospects for biodiversity conservation in the Atlantic Forest: Lessons from aging human-modified landscapes   总被引：1，自引：0，他引：1  

Marcelo Tabarelli  Antonio Venceslau Aguiar  Jean Paul Metzger 《Biological conservation》2010,143(10):2328-2340

Recent global assessments have shown the limited coverage of protected areas across tropical biotas, fuelling a growing interest in the potential conservation services provided by anthropogenic landscapes. Here we examine the geographic distribution of biological diversity in the Atlantic Forest of South America, synthesize the most conspicuous forest biodiversity responses to human disturbances, propose further conservation initiatives for this biota, and offer a range of general insights into the prospects of forest species persistence in human-modified tropical forest landscapes worldwide. At the biome scale, the most extensive pre-Columbian habitats across the Atlantic Forest ranged across elevations below 800 masl, which still concentrate most areas within the major centers of species endemism. Unfortunately, up to 88% of the original forest habitat has been lost, mainly across these low to intermediate elevations, whereas protected areas are clearly skewed towards high elevations above 1200 masl. At the landscape scale, most remaining Atlantic Forest cover is embedded within dynamic agro-mosaics including elements such as small forest fragments, early-to-late secondary forest patches and exotic tree monocultures. In this sort of aging or long-term modified landscapes, habitat fragmentation appears to effectively drive edge-dominated portions of forest fragments towards an early-successional system, greatly limiting the long-term persistence of forest-obligate and forest-dependent species. However, the extent to which forest habitats approach early-successional systems, thereby threatening the bulk of the Atlantic Forest biodiversity, depends on both past and present landscape configuration. Many elements of human-modified landscapes (e.g. patches of early-secondary forests and tree monocultures) may offer excellent conservation opportunities, but they cannot replace the conservation value of protected areas and hitherto unprotected large patches of old-growth forests. Finally, the biodiversity conservation services provided by anthropogenic landscapes across Atlantic Forest and other tropical forest regions can be significantly augmented by coupling biodiversity corridor initiatives with biota-scale attempts to plug existing gaps in the representativeness of protected areas.  相似文献   

The Plant Disease Clinic and Field Diagnosis of Abiotic Diseases     

Teresa Coutinho  & Bernard Slippers 《Plant pathology》1999,48(4):564-564

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Gastric coccidiosis in Thoracocharax stellatus caused by Goussia guamaensis n. sp. (Apicomplexa: Eimeriidae) from the Amazon region     

Marcelo F. da Silva  Rebeca S. de Araújo  Diehgo T. da Silva  Osimar Sanches  Igor Hamoy  Edilson Matos 《Journal of fish diseases》2019,42(6):905-912

Ninety‐seven specimens of spotfin hatchetfish, Thoracocharax stellatus, an ornamental freshwater species from the Amazon basin, were captured in the basin of the Guamá River in the municipality of Belém, in northern Brazil, and analysed for coccidiosis infection. Overall, 26 of the specimens were infected by apicomplexan parasites of the genus Goussia, with unsporulated forms being found in the gastric epithelium and sporulated forms in the intestinal lumen. The spheroid oocysts (mean diameter: 13.2 ± 1.7 μm) have four elliptical sporocysts. A partial sequence of the SSU rDNA of the new species was obtained, which contained 1,121 base pairs, with 43.8% guanine + cytosine (G + C), and the bases distributed as follows: A = 28.1%, C = 18.3%, G = 25.5% and T = 28.1%. The combined analysis of the morphometric and phylogenetic evidence confirmed that the specimens represented the genus Goussia and were allocated to a new species, Goussia guamaensis n. sp., which is described here.  相似文献   

Agronomic,nutritive value,reproductive, cytogenetic,and molecular aspects of Paspalum accessions: Contribution to the development of new forage cultivars     

Frederico de Pina Matta  Alessandra Pereira Fávero  Bianca Baccili Zanotto Vigna  Marisa Toniolo Pozzobon  Sergio Raposo de Medeiros  Waldomiro Barioni Júnior  Marcelo Mattos Cavallari 《Grass and Forage Science》2023,78(1):101-118

This study investigated the agronomic, nutritive value, cytogenetic, molecular, and reproductive aspects of twenty-five Paspalum accessions to support breeding programs. The agronomic aspects and the nutritive value were evaluated in a randomized block experimental design with four replications, and with monthly repeated measures for 2 years. For the molecular characterization 16 microsatellite markers developed for different Paspalum species in previous works were used. The number of chromosomes was determined by visualizing the meiotic cells and the DNA content was determined by flow cytometry. The embryo sac clarification technique was used to characterize the reproductive system. T he results indicated genetic variability for all the variables related to yield and nutritive value. For almost all variables, the values of Paspalum accessions were higher than those of the commercial cultivars Megathyrsus maximus cv. Tanzania and Urochloa brizantha cv. Marandu, used as references. However, the accessions showed in vitro dry matter digestibility values lower than the mean value presented by the references. The groups formed in the molecular analysis showed correspondence to the groups observed in the principal components analysis, considering the variables related to yield and nutritive value. Most accessions were revealed to be tetraploid with 40 chromosomes and most accessions belonging to the Virgata group displayed a sexual embryo sac structure . Some crosses can be indicated for genetic breeding, due to a superior genomic affinity between the accessions and the higher probability of heterosis in the progeny. These results provide subsidies to genetic plant breeding programs that use these accessions.  相似文献   

Variability in the solubility of agricultural limestone from different sources and its pertinence for aquaculture          下载免费PDF全文

Marcelo Vinicius do Carmo e Sa  Claude E Boyd 《Aquaculture Research》2017,48(8):4292-4299

Samples of agricultural limestone were obtained from quarries in the USA as follows: Talking Rock, GA; Whitestone, GA; Austinville, VA; Bonham, TX; and Thomasville, PA, referred as GA‐1, GA‐2, VA, TX and PA respectively. The limestone products were tested initially for non‐equilibrium pH, concentrations of calcium and magnesium, neutralizing value (NV) and fineness rate. Laboratory solubility test of the products was conducted in which pH, specific conductance (SC), total alkalinity (TA), total and calcium hardness were measured weekly for 9 weeks. It was found that the agricultural limestone samples had comparable chemical compositions, that is NV (97–108%), Ca (19.8–32.1%), Mg (3.2–12.2%), pH of slurry (8.1–9.7), but somewhat different solubilities in water. Total alkalinity concentrations at equilibrium ranged from 30 to 60 mg L^?1. It was possible to quickly estimate the relative solubility of different agricultural limestone samples by comparing their specific conductance under standardized conditions (2.0 g samples w/0.15–0.25 mm fineness; 3.5 L distilled water; 24 h). This procedure might be helpful in achieving better results when liming aquaculture ponds, that is choosing the agricultural limestones with the highest solubilities in water.  相似文献   

Lack of essential fatty acids in live feed during larval and post-larval rearing: effect on the performance of juvenile <Emphasis Type="Italic">Solea senegalensis</Emphasis>     

Maria Luísa Dâmaso-Rodrigues  Pedro Pousão-Ferreira  Laura Ribeiro  Joana Coutinho  Narcisa M. Bandarra  Paulo J. Gavaia  Luís Narciso  Sofia Morais 《Aquaculture International》2010,18(5):741-757

Despite the large progress obtained in recent years, Senegalese sole (Solea senegalensis) production of high quality juveniles is still a bottleneck. This paper examines the effect of larval and post-larval lipid nutrition on juvenile performance and quality. Four dietary treatments were tested: A—enriched Artemia spp. (EA); B—non-enriched Artemia spp. (NEA); C—EA during the pelagic larval period and NEA after larval settlement; D—50% EA and 50% NEA. Juvenile fatty acid profile at 60 days after hatching (DAH) clearly reflected the larval and post-larval diet composition. Feeding sole larvae on NEA (poor in lipids and essential fatty acids-EFA) had a negative effect, reducing growth (total length and dry weight) after 30 DAH and decreasing digestive enzyme activity at the end of the rearing period (60 DAH). However, relatively good performance compared to the EFA-richest treatment (A) was obtained when larvae were fed 50% EA and 50% NEA (D) or even EA only during the pelagic larval period followed by NEA after larval settlement (C). Malpigmentation was not affected by the dietary regimes and its incidence was very low. However, skeletal deformities were prevalent, particularly in the caudal complex, independently of diet. The results confirm that Senegalese sole appear to have lower larval EFA requirements than most cultured marine species and potentially even lower requirements during the post-larval stage. The importance of studying the impact of early nutrition on later juvenile stages was clearly highlighted in this study.  相似文献   

Early development of the silver catfish Rhamdia quelen (Quoy & Gaimard, 1824) (Pisces:Heptapteridae) from the São Francisco River Basin, Brazil     

Marcelo Pimenta de Amorim  Bruno Vilaça Campos Gomes  Yuri Simões Martins  Yoshimi Sato  Elizete Rizzo  & Nilo Bazzoli 《Aquaculture Research》2009,40(2):172-180

The silver catfish, Rhamdia quelen , is endemic to North, Central and South America with high aquaculture potential and wide acceptance in the market. Breeder fish were subjected to induced reproduction through hypophysation using a crude common carp pituitary extract. Egg characteristics, oocyte surface ultrastructure and histology of larval ontogenesis until whole yolk resorption were described for the first time for this species. Oocytes and semen were obtained by manual extrusion, and fertilization was conducted using the dry method. After fertilization, eggs were kept in incubators at 24 °C. The embryonic development was monitored using a stereomicroscope every 10 min until hatching. To analyse the larval development, larvae samples were collected from incubators daily until the fifth day, fixed in Bouin's fluid and subjected to routine histological techniques. The oocyte extrusion occurred 8 h after the second hormone dose at 26 °C. The oocytes were spherical, non-adhesive and yellow, with a diameter of 1471.75±47.63 μm. Scanning electron microscopy revealed a thin jelly coat covering the zona radiata in the animal pole around the micropyle. The blastopore closure occurred within 8 h after fertilization, and the fertilization rate was 79.9±5.2% at 24 °C. Embryonic development was completed within 25 h 30 min after fertilization. The complete resorption of the yolk and the formation of the digestive system organs and the mouth opening occurred on the fifth day, indicating a need for exogenous feeding. The results of this study provide information important for improvement in R. quelen culture and management.  相似文献   

Detection of Bemisia tabaci Mediterranean cryptic species on soybean in São Paulo and Paraná States (Brazil) and interaction of cowpea mild mottle virus with whiteflies     

Vinicius Henrique Bello  Felipe Barreto da Silva  Luís Fernando Maranho Watanabe  Eduardo Vicentin  Cristiane Muller  Regiane Cristina Oliveira de Freitas Bueno  Jessica Costa Santos  Bruno Rossitto De Marchi  Angélica Maria Nogueira  Valdir Atsushi Yuki  Julio Massaharu Marubayashi  Maria Márcia Pereira Sartori  Marcelo Agenor Pavan  Murad Ghanim  Renate Krause-Sakate 《Plant pathology》2021,70(6):1508-1520

Since the detection of Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) species in Brazil in the early 1990s, this whitefly has been the predominant species and the main viral vector in the country. In this work, whiteflies were collected from commercial soybean fields near and far from greenhouses where Mediterranean (MED) species had previously been detected infesting vegetable crops. Results indicated that MEAM1 was the predominant whitefly species in soybean in most sampling sites, while MED was found colonizing soybean plants in open field conditions alone and/or with MEAM1 in several places. Among the tested insects, MED species was mostly detected harbouring the facultative endosymbiont Hamiltonella. We also detected cowpea mild mottle virus (CPMMV) infecting soybean plants. Transmission assays demonstrated that MED species was more efficient transmitting CPMMV from beans to beans and from soybean to soybean plants than MEAM1, while MEAM1 was more efficient in transmitting the virus from soybean to bean than MED. Performance assays indicated that adult emergence of both species on CPMMV-infected soybean plants was higher when compared with the emergence on healthy plants. Moreover, nonviruliferous MED and MEAM1 adults preferred to settle more often on healthy plants, while viruliferous adults settled more often on CPMMV-infected soybean plants. As MED has already been found in soybean open fields in São Paulo and Paraná States, Brazil, and it is a good vector of CPMMV, we anticipate problems related to whitefly management and to increase in the incidence of the virus in soybean.  相似文献   

Population structure of the critically endangered Brazilian guitarfish Pseudobatos horkelii (Rhinobatidae) revealed by double-digest restriction site-associated DNA sequencing     

Yan Torres  Matheus Marcos Rotundo  Marcelo Vianna  Patricia Charvet  Vicente Vieira Faria  Claudio Oliveira  Fausto Foresti  Vanessa Paes Cruz 《水产资源保护:海洋与淡水生态系统》2024,34(1):e4035