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排序方式: 共有250条查询结果,搜索用时 781 毫秒
1.
S. Leal‐Soto R. Barraza‐Guardado R. Castro‐Longoria J. Chvez‐Villalba F. Hoyos‐Chirez 《Journal of the World Aquaculture Society》2011,42(6):789-800
Pen shells are economically important and most are threatened by overexploitation and habitat degradation. Cultivation represents an alternative for preserving the resource and increasing the production. Atrina maura was cultivated in a suspension system which was followed by a bottom phase. Samples of pen shells and tissues were collected monthly to measure absolute growth, shell height increase, and an adductor muscle index. After the trials, adults shell height was 195 ± 10 mm, total weight was 223 ± 28 g, and mean shell height increase was 0.81 cm/mo. Protective devices were vital to avoid predation by crabs and fish; survival was 90% in the suspension phase and 70% in the bottom phase. Variations in the muscle index were apparently related to reproduction, suggesting activity (partial spawning) from August 2008 to April 2009 in juveniles and a major spawning in adults during August 2009. Adductor muscles reached a mean of 21 g after 20 mo of cultivation, but muscle weights decreased significantly after reproduction (August to November 2009). Results indicated that A. maura is suitable for aquaculture and the cultivation system adopted here should be tested in pilot‐scale ventures. This system may work with other species of pen shells. 相似文献
2.
Pablo M. Vergara Luis O. Meneses Audrey A. Grez Madelaine S. Quiroz Gerardo E. Soto Christian G. Pérez-Hernández Paola A. Diaz Ingo J. Hahn Andrés Fierro 《Landscape Ecology》2017,32(2):279-293
Context
Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.Objectives
We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.Methods
We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).Results
Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.Conclusions
M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.3.
4.
Faridy Juárez-Chairez Milagros Stephanie Cid-Gallegos María Gabriela Meza-Márquez Ofelia Cristian Jiménez-Martínez 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(2):142-153
Plant Foods for Human Nutrition - Chickpea is one of the most consumed legumes worldwide. Among their benefits are the high protein concentration that reflects not only at the nutritional level but... 相似文献
5.
Detection and characterization of a rhabdovirus causing mortality in black bullhead catfish,Ameiurus melas 下载免费PDF全文
Giulia Bedendo Valentina Panzarin Andrea Fortin Gianpiero Zamperin Tobia Pretto Alessandra Buratin Rosita Quartesan Matteo Sabbion Cristian Salogni Francesco Pascoli Anna Toffan 《Journal of fish diseases》2018,41(7):1063-1075
This study fully describes a severe disease outbreak occurred in 2016 in black bullhead catfish farmed in Italy. Affected fish showed nervous clinical signs as well as emaciations and haemorrhagic petechiae on the skin at the fin bases, abdomen and gills. Viral isolation in cell culture allowed the subsequent identification of a rhabdovirus, tentatively named ictalurid rhabdovirus (IcRV), through electron microscopy, immunofluorescence and whole genome sequencing (WGS). The newly isolated virus, together with 14 additional viral strains stored in our repository and detected during similar mortality episodes in the period 1993–2016, was phylogenetically analysed on the basis of the nucleoprotein and the glycoprotein nucleotide and amino acid sequences. The genetic distances among Italian IcRV strains were also estimated. Our results show that all the IcRV strains belong to the genus Sprivivirus and are closely related to the tench rhabdovirus (TenRV). Italian catfish production is constantly decreasing, mainly due to viral infections, which include the newly characterized IcRV. Data presented in this work will assist to investigate the molecular epidemiology and the diffusive dynamics of this virus and to develop adequate surveillance activities. 相似文献
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Fumuso E Checura C Losinno L Soto P Sánchez S 《Veterinary research communications》2002,26(5):371-380
Endometritis in mares is a common cause of infertility. Conventional treatments of the disease have mostly been unsuccessful, so new therapeutic alternatives need to be investigated. This study evaluated the uterine disposition and plasma pharmacokinetic behaviour of a commercial formulation of enrofloxacin (EFX) given by the intrauterine (i.u.) route (2.5 mg/kg) in healthy mares. In order to evaluate the uterine inflammatory response, an initial histopathological study assessing polymorphonuclear cell infiltration was carried out in 20 mares over a 14-day period after treatment. In a second study, 6 healthy adult mares were used for the pharmacokinetic study. Samples of uterine tissue and plasma were collected from 0 to 24 h after the i.u. treatment with 5% EFX solution. Samples were analysed by conventional microbiological assay using an EFX-sensitive strain of Escherichia coli (ATCC 25922). There was a moderate but statistically nonsignificant inflammatory response following i.u. administration of either the formulation or the vehicle alone. Pharmacokinetic analysis of the uterine concentrations of EFX showed a slow and sustained depletion, with EFX remaining at concentrations above the MIC for 24 h after treatment. The area under the concentration–time curve obtained for the uterus suggested that EFX and its metabolites are specifically retained in the uterus, which is the target tissue for bacterial colonization. Neither study provided any evidence of EFX toxicity. In conclusion, these results are encouraging and suggest that EFX may be a useful local treatment in mares with bacterial endometritis. 相似文献
9.
For experimental infections with viscerotropic strains of Leishmania, a suitable animal model is not yet defined. In the present work, we have reappraised the use of golden hamster (Mesocricetus auratus) as an experimental model for infection with Leishmania infantum. Groups of hamsters were challenged by the intracardial route with doses ranging from 10(3) to 10(5) infectious promastigotes and the animals were monitored for 1-year follow-up period. The outcome of the infection was assessed by clinical symptoms of leishmaniasis, parasite loads in both liver and spleen, humoral response to Leishmania antigens and antibody levels in kidneys. The humoral response was analysed using either crude antigens (by ELISA and Western blotting) or several recombinant Leishmania antigens (Hsp70, Hsp83, LiP2a, LiP2b, H2A, H3 and KMP-11). From the analysis of all these parameters, we established the existence of three groups of animals: symptomatic or susceptible, oligosymptomatic, and resistant. Given the parallelism existing between the outcomes of Leishmania-infection in hamsters, dogs and humans, we believe that our data illustrate that the hamster is an excellent experimental model to study visceral leishmaniasis and for the design of vaccine development. 相似文献
10.
Concetta Burgarella Miguel Navascués Álvaro Soto Ángel Lora Silvio Fici 《Annals of Forest Science》2007,64(7):757-763
In order to empirically assess the effect of actual seed sampling strategy on genetic diversity of holm oak (Quercus ilex) forestations in Sicily, we have analysed the genetic composition of two seedling lots (nursery stock and plantation) and their known natural seed origin stand by means of six nuclear microsatellite loci. Significant reduction in genetic diversity and significant difference in genetic composition of the seedling lots compared to the seed origin stand were detected. The female and the total effective number of parents were quantified by means of maternity assignment of seedlings and temporal changes in allele frequencies. Extremely low effective maternity numbers were estimated (Nf e ≈ 2–4) and estimates accounting for both seed and pollen donors gave also low values (N e ≈ 35–50). These values can be explained by an inappropriate forestry seed harvest strategy limited to a small number of spatially close trees. 相似文献