排序方式: 共有87条查询结果,搜索用时 0 毫秒
51.
52.
53.
RNAi as an emerging approach to control Fusarium head blight disease and mycotoxin contamination in cereals 下载免费PDF全文
Ana Karla Machado Neil A Brown Martin Urban Kostya Kanyuka Kim E Hammond‐Kosack 《Pest management science》2018,74(4):790-799
Fusarium graminearum is a major fungal pathogen of cereals worldwide, causing seedling, stem base and floral diseases, including Fusarium head blight (FHB). In addition to yield and quality losses, FHB contaminates cereal grain with mycotoxins, including deoxynivalenol, which are harmful to human, animal and ecosystem health. Currently, FHB control is only partially effective due to several intractable problems. RNA interference (RNAi) is a natural mechanism that regulates gene expression. RNAi has been exploited in the development of new genomic tools that allow the targeted silencing of genes of interest in many eukaryotes. Host‐induced gene silencing (HIGS) is a transgenic technology used to silence fungal genes in planta during attempted infection and thereby reduces disease levels. HIGS relies on the host plant's ability to produce mobile small interfering RNA molecules, generated from long double‐stranded RNA, which are complementary to targeted fungal genes. These molecules are transferred from the plant to invading fungi via an uncharacterised mechanism, to cause gene silencing. Here, we describe recent advances in RNAi‐mediated control of plant pathogenic fungi, highlighting the key advantages and disadvantages. We then discuss the developments and implications of combining HIGS with other methods of disease control. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献
54.
Ingrid Alexssandra Neris Lino Vilma Maria dos Santos Indra Elena Costa Escobar Danielle Karla Alves da Silva Ademir Srgio Ferreira de Araújo Leonor Costa Maia 《Land Degradation \u0026amp; Development》2016,27(1):77-82
Eucalyptus plantations have become increasingly common in Latin America. However, because Eucalyptus is an exotic species, its presence has raised concerns about changes in the environment, especially to soil properties. The objective of this study was to investigate possible changes in selected soil enzyme activity after several years of Eucalyptus cultivation. Soil samples were collected from four locations: a native forest (Atlantic Forest) used as a reference for the original soil conditions and three E. grandis plantations aged 2, 3 and 5 years, established in 2008, 2007 and 2005, respectively. The native vegetation had been removed and the soil graded and ploughed to establish these plantations. We evaluated soil enzymatic activities (β‐glucosidase, acid phosphatase, dehydrogenase, urease and arylsulfatase) at each location. The activity of β‐glucosidase, phosphatase, dehydrogenase and urease was improved after 5 years, whereas arylsulphatase was impacted negatively. The multivariate analysis showed that the majority of enzyme activities reached the values observed in native forest after the third year of reforestation. The activity of β‐glucosidase was crucial in differentiating the area with 2 years of reforestation from the native forest. The removal of native vegetation in order to establish commercial plantations raises concerns about the real impacts of this practice on the soil. In the present study, plantations of Eucalyptus improved most of the selected enzyme activities after the third year of reforestation. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
55.
Karla Meza Makoto Inami Alf S. Dalum Hege Lund Ane M. Bjelland Henning Srum Marie Lvoll 《Journal of fish diseases》2019,42(12):1713-1730
The Chilean aquaculture has been challenged for years by piscirickettsiosis. A common prophylactic measurement to try to reduce the impact from this disease is vaccination, but the development of vaccines that induce satisfactory protection of the fish in the field has so far not been successful. Experimental challenge models are used to test vaccine efficacy. The aim of this study was to evaluate the performance of experimental vaccines after challenge by the two most widely used challenge routes, intraperitoneal injection and cohabitation. A total of 1,120 Atlantic salmon were vaccinated with non‐commercial experimental vaccines with increasing amounts of an inactivated Piscirickettsia salmonis EM90‐like isolate. Differences in mortality, macroscopic and microscopic pathological changes, bacterial load and immune gene expression were compared after challenge by different routes. The results revealed a similar progression of the diseases after challenge by both routes and no gross differences reflecting the efficacy of the vaccines could be identified. The analysis of the immune genes suggests a possible suppression of the cellular immunity by CD8 T cell and with this stimulation of bacterial survival and replication. Comparative studies of experimental challenge models are valuable with regard to identifying the best model to mimic real‐life conditions and vaccines’ performance. 相似文献
56.
57.
58.
Karla Paola Picoli Alice Eiko Murakami Ricardo Vianna Nunes Cristiane Regina do Amaral Duarte Cinthia Eyng Ivan Camilo Ospina-Rojas 《Tropical animal health and production》2014,46(8):1371-1381
The objective of this study was to evaluate the effect of inclusion of dehydrated cassava starch residue (DCSR) on the performance, gastrointestinal tract characteristics and carcass traits of ISA Label JA57 slow-growing broilers. A total of 510 broilers at 21 were distributed in a randomized experimental design with 5 treatments (2, 4, 6, 8, and 10 % DCSR inclusion) and a control group, 5 replicates, and 17 birds per experimental unit. The DCSR inclusion from 21 to 49 days of age negatively influenced (P?0.05) weight gain and feed intake and did not affect (P?>?0.05) feed conversion in the broilers with increasing of DCSR inclusion. From 21 to 79 days, DCSR inclusion impaired (P?0.05) weight gain, feed conversion, and poultry litter quality with increasing of DCSR inclusion. The level of blood triglycerides showed a quadratic response (P?0.05) at 79 days of age with the highest value predicted to occur at 5.45 % of DCSR inclusion. DCSR levels affected (P?0.05) the gastrointestinal organ characteristics, cecal content pH, and pigmentation of the shank, breast, and thigh meat of the birds but did not alter (P?>?0.05) the other parameters of carcass quality and yield, cuts, and percentage of abdominal fat. In conclusion, DCSR inclusion levels above 2 % compromised broiler performance. 相似文献
59.
Rosa Karla Nogueira Pestanana Edson Perito Amorim Cláudia Fortes Ferreira Vanusia Batista de Oliveira Amorim Larissa Santos Oliveira Carlos Alberto da Silva Ledo Sebastião de Oliveira e Silva 《Euphytica》2011,178(2):151-158
Bananas are tropical fruits grown worldwide playing a key role in market trade and especially used as main food source for
low income populations. In Brazil, bananas are mainly consumed in natura, occupying the second largest internal market. Nevertheless, this crop presents low availability of productive commercial
varieties with good agronomic characteristics. A strategy undertaken to solve this problem is the development of new cultivars
through conventional genetic breeding methods. However, this strategy presents some obstacles such as female sterility and
low number of seeds. In order to overcome these shortcomings, use of mutation induction aiming the selection of mutants with
desirable agronomic characteristics seems to have great potential for developing new cultivars. The objective of the present
work was to evaluate the genetic variability in putative banana ‘Pacovan’ (AAB genome, subgroup Prata Type) mutants submitted
to gamma ray irradiation, using a set of agronomical and molecular data (ISSR markers). The distance between the putative
‘Pacovan’ mutants varied from 0.26 to 0.64 with cophenetic correlation coefficient of 0.7669. Four mutants were selected based
on best agronomical characteristics and height. This data also shows that there is variability that can be explored after
the irradiation of ‘Pacovan’ banana mutants, which can be used in the genetic breeding program of banana aiming to develop
short new varieties that also present good agronomic characteristics. This is the first attempt to use combined data in order
to evaluate the genetic variability in putative banana mutants. 相似文献
60.
Pablo Garcia Karla Aspee Georges Ramirez Phillip Dettleff Jaime Palomino Oscar A. Peralta Víctor H. Parraguez Monica De los Reyes 《Reproduction in domestic animals》2019,54(2):373-380
Growth differentiation factor 9 (GDF‐9) and bone morphogenetic protein 15 (BMP‐15) have pivotal roles in oocyte development in many species, therefore the aim was to investigate these factors during in vitro maturation (IVM) of canine oocytes. Canine cumulus oocytes complexes (COCs) were cultured in six groups for 72 hr in a supplemented TCM199‐Hepes medium as (a) Control group; (b) GDF‐9 antibody (Ab); (c) BMP‐15 Ab; (d) recombinant human (rh) GDF‐9; (e) rh BMP‐15 or (f) rh BMP‐15 and GDF‐9. Data were evaluated by ANOVA. The Abs against GDF‐9 or BMP‐15 had a negative impact on meiotic development. Higher (p < 0.05) number of oocytes was arrested at GVBD stage when they were incubated with either GDF‐9 Ab (64.4 ± 2.1%) or BMP‐15 Ab (67.2%± 4.9%) in comparison to those in control group (32.4 ± 7.8%). In contrast, more (p < 0.05) oocytes in control group reached MI (37.4 ± 1.3%) and MII stages (10.2 ± 2.1%) comparing to those groups with GDF‐9 Ab (23.1 ± 4.7% MI; 0.0% MII) or BMP‐15 Ab (16.4 ± 2.4%MI; 5.9% ± 2.1 MII). Higher rates (p < 0.05) of oocytes in control group stayed still arrested at GV (19.9 ± 8.6%) in comparison to those cultured with either rhGDF‐9 (3.7 ± 0.4%) or rhBMP‐15 (10.9 ± 0.7%). However, there were no differences in MII rates between oocytes cultured with GDF‐9 (14.7 ± 3.1) and BMP‐15 (7.8 ± 2.5) separately. But, more oocytes (p < 0.05) reached the MII stage (20.5 ± 3.8%) compared to those exposed to each protein separately and to the control group. These results suggest that these proteins likely contribute to the meiotic development in dogs. 相似文献