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1.
Sindbis virus mutants selected for rapid growth in cell culture display attenuated virulence in animals 总被引：16，自引：0，他引：16
Mutants of Sindbis virus were selected for rapid growth in baby hamster kidney (BHK) cell cultures and screened for attenuation of virulence in suckling mice. Comparisons among independently isolated virulent and attenuated strains, as well as a classical reversion analysis, showed that accelerated penetration of BHK cells was correlated with attenuation in vivo. Both phenotypic changes resulted from a reorganization of virion structure as detected by monoclonal antibodies. These results suggest that mutants selected for rapid growth in cell culture may be useful as attenuated vaccines and for studies of the molecular basis of virus pathogenesis. 相似文献
2.
Sanja Baric 《Erwerbs-Obstbau》2012,54(3):147-153
Apple proliferation caused by ‘Candidatus Phytoplasma mali’ is an economically important disease of apple (Malus?′?domestica). The availability of a simple quantitative approach to assess pathogen load in infected host plants would certainly contribute to a better understanding of pathogenesis and epidemiology. This study proposes a quantification approach not requiring the analysis of external standard curves. It is based on the simultaneous detection of the 16S rRNA gene of the pathogen and the 1-aminocyclopropane-1-carboxylate oxidase gene of the host plant in a single-tube reaction using TaqMan chemistry. The quantity of the phytoplasma relative to its host plant is determined as the difference between CT values of the two target genes (ΔCT). To assess the agreement of the relative quantification approach with a standard curve-based method, a dataset of 450 DNA samples from infected apple trees was reanalysed. Comparison of the ΔCT-based relative quantities with the corresponding absolute values revealed high degrees of agreement between the relative and absolute quantification methods. The ΔCT procedure can thus be considered adequate for quantification of the phytoplasma in infected host plant tissue. In addition, this approach ensures improved methodological standardisation and increased analysis throughput. 相似文献
3.
In the mid-1970s, a new apple variety named ‘Meran’ was discovered in South Tyrol (northern Italy), which harbours the largest continuous apple growing area in Europe. The cultivar was registered for varietal protection and patented in several countries, and was declared to be a cross of the varieties ‘Golden Delicious’ and ‘Morgenduft’ (synonym ‘Rome Beauty’). The parentage of ‘Meran’ has, however, been questioned, and the present study aimed to assess the descent of this cultivar by the combined use of molecular genetic and bioinformatic tools. Five accessions of ‘Meran’ were collected from three different European germplasm collections and analysed at 14 variable microsatellite DNA loci. Subsequently, computer software was used to allocate the most likely parent pair from a set of cultivars representative for the apple growing area of South Tyrol in 1975. The molecular genetic data clearly excluded ‘Morgenduft’ as a gene donor to ‘Meran’ and provided strong evidence that ‘Meran’ is a cross of the cultivars ‘Golden Delicious’ and ‘Jonathan’, confirming previous assumptions based on morphological traits of the tree and fruit. 相似文献
4.
Sanja Baric 《Erwerbs-Obstbau》2012,54(3):125-135
Molecular biology techniques have become indispensable tools in various areas of research and routine applications. In South Tyrol (northern Italy), molecular methods have been applied to the field of fruit growing over the last decade, and the main applications have been related to plant pathology and identification of apple cultivars. This review article illustrates how the implementation of existing methods and the development of new assays have contributed to gain more insights about the spread and epidemiology of phytoplasma diseases affecting apple trees and grapevine in South Tyrol, to identify and characterise the causal agents of newly emerging disorders, or to describe the local genetic diversity of the apple. 相似文献
5.
South Tyrol (northern Italy) harbours the largest continuous apple producing area in Europe, with an annual fruit harvest of around one million of metric tonnes. Every tenth apple produced in EU-28 originates from South Tyrol and this fruit thus represents the most important export product of this region, which contributes to 55 % of the added value from agriculture. The success of apple production depends on several key factors, one of which is education and professional training in agriculture and fruit production, and this topic is elaborated in greater detail in the present work. In 1874, the ‘Agricultural Institute and Experimental Station’ in S. Michele upon Etsch/Adige was inaugurated as an institution for higher agricultural education and research for the entire territory of the historical Tyrol. The first vocational school for agriculture in South Tyrol was founded in 1909 in Sterzing/Vipiteno (later transferred to Dietenheim/Teodone nearby Bruneck/Brunico), but soon, with World War I, the agricultural education in German language collapsed completely and was re-established only after World War II. The work of the vocational school in Dietenheim/Teodone was pursued, and in 1952 opened the Vocational School for Agriculture and Forestry Fürstenburg, in 1962 the Vocational School for Fruit, Viticulture and Horticulture Laimburg and in 1978 the Vocational School for Agriculture and Domestic Economy Salern. Increasing student numbers demonstrate the success of these schools. In 1980, finally, the High School for Agriculture in Auer/Ora nearby Bozen/Bolzano was founded and in 1999 started the Bachelor’s study programme in Agricultural Technology and Economics at the Free University of Bozen/Bolzano. Nowadays, the agricultural education in South Tyrol is covered by a full range of school types ranging from vocational schools to university level doctoral studies. 相似文献
6.
Cacciò SM Antunovic B Moretti A Mangili V Marinculic A Baric RR Slemenda SB Pieniazek NJ 《Veterinary parasitology》2002,106(4):285-292
The morphologically small Babesia species isolated from naturally infected dogs in Europe, Japan, and US are described as Babesia gibsoni despite the fact that molecular techniques show that they should be assigned to two or three separate taxons. The morphologically large Babesia isolated from dogs in Europe, Africa, and US were generally classified as B. canis until it was proposed to distinguish three related, albeit genetically distinct subspecies of this genus, namely B. canis canis, B. canis rossi, and B. canis vogeli. The insight into the molecular taxonomy of canine piroplasms is, however, limited because only partial small subunit ribosomal RNA (ssrRNA) sequence data exist for two species from the B. canis group. In this work, we molecularly characterised natural Babesia infections in 11 dogs from Croatia, France, Italy, and Poland. These infections were diagnosed as caused by B. canis canis and B. canis vogeli based on the analysis of the complete sequence of the ssrRNA genes. Phylogenetic analysis confirmed that the large Babesia species of dogs belong the to the Babesia sensu stricto clade, which includes species characterised by transovarial transmission in the tick vectors and by exclusive development inside the mammalian host erythrocytes. The new data facilitate the reliable molecular diagnosis of the subspecies of B. canis. 相似文献
7.
Sanja Baric Jennifer Berger Christian Cainelli Christine Kerschbamer Josef Dalla Via 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(4):573-584
Apple proliferation caused by ‘Candidatus Phytoplasma mali’ is a disease of apple trees gaining increasing importance in Europe. The present study describes a high-throughput
method for simultaneous typing of ‘Ca. P. mali’ at two genetic loci. This novel approach combines terminal restriction fragment length polymorphism (T-RFLP) analysis
of a putative rhodanese-like protein gene and the analysis of the variable number of tandem repeats (VNTR) of the ribosomal
protein L22 gene. The typing approach was applied to analyse a collection of DNA isolates from 310 apple trees tested positive
for ‘Ca. P. mali’. Samples were taken between 2002 and 2010 in South Tyrol (Northern Italy). In addition, 15 samples of Cacopsylla melanoneura and 19 of C. picta were typed. Seven combined genetic profiles were found in the samples of infected apple trees: AT-2/rpX-A (81.0%), AT-1/rpX-D
(8.4%), AT-1/rpX-E (4.2%), AT-1/rpX-A (3.2%), AT-1/rpX-B (1.6%), AT-1/rpX-C (1.0%) and AP/rpX-A (0.3%), and one mixed infection
AP + AT-1/rpX-A + rpX-D (0.3%). Subtype rpX-E was discovered for the first time. In C. melanoneura samples the most frequent subtype was AT-1/rpX-E, followed by AT-1/rpX-D and AT-1/rpX-C. All C. picta samples displayed subtype AT-2/rpX-A. Analysis of the temporal distribution of subtype frequencies in apple trees revealed
that exclusively subtype AT-1 in combination with four rpX subtypes was present in South Tyrol in the period from 2002 to
2004. From 2006 onwards subtype AT-2/rpX-A became dominant with an average frequency of 90%. The data obtained suggest that
there may be a co-adaptation of particular ‘Ca. P. mali’ subtypes with different insect vector species. 相似文献
8.
Sanja Baric Jennifer Berger Christian Cainelli Christine Kerschbamer Thomas Letschka Josef Dalla Via 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(3):455-467
Apple proliferation (AP), caused by ‘Candidatus Phytoplasma mali’, is an economically important disease affecting many apple-growing areas in Europe. A new TaqMan real-time
PCR assay was established for absolute quantification of ‘Ca. P. mali’ by using a single-copy gene of the host plant as a reference, which is amplified with the pathogen DNA in a single-tube
reaction. Normalised estimates of phytoplasma concentration are ultimately expressed as the number of phytoplasma cells per
host plant cell. The assay was used to monitor the ‘Ca. P. mali’ titre over the course of two growing seasons in roots and branches of symptomatic and asymptomatic but AP-positive
apple trees. All 252 root samples from symptomatic and asymptomatic trees tested positive, with an average number of 59.8 ± 5.68
(standard error) and 55.1 ± 9.83 ‘Ca. P. mali’ per host cell, respectively. From the 378 shoot samples analysed, 81% of the symptomatic and only 20% of the asymptomatic
samples were AP-positive with an average number of 9.4 ± 1.04 and 0.7 ± 0.13 ‘Ca. P. mali’ per host cell, respectively. This strengthens evidence that not the pathogen occurrence alone but the presence of
a certain quantity of ‘Ca. P. mali’ in the aerial tree sections is involved in symptom expression. In addition, pronounced seasonality of the phytoplasma
concentration was found, not only in branches, but also for the first time in roots of symptomatic and asymptomatic apple
trees. Highest phytoplasma levels in roots were detected from December to May. 相似文献
9.
Amaral Carneiro Greice Walcher Magdalena Baric Sanja 《European journal of plant pathology / European Foundation for Plant Pathology》2022,162(1):247-255
European Journal of Plant Pathology - Recently, Cadophora luteo-olivacea has been reported as a post-harvest pathogen of side rot of apple (Malus domestica) in Latvia, and of pear (Pyrus communis)... 相似文献
10.
Sanja Baric Christine Kerschbamer Josef Vigl Josef Dalla Via 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):207-211
Apple proliferation (AP), a phytoplasma-induced disease of apple trees, was proven to be transmitted through infected grafting
material and sap-sucking insects. To date there are little firm data on disease propagation in the field via natural root
grafts. This question was thus addressed in the present case study by investigating trees of a 24-year old commercial apple
orchard (‘Red Chief’ on MM 111), where the existence of root connections was discovered accidentally. After having displayed
specific AP symptoms, nine trees were cut down and the stubs were infiltrated or brushed with glyphosate. Herbicide injury,
however, remained not only restricted to the treated stubs, but also spread to approximately 50 neighbouring trees. Surprisingly,
none of the pollinators (‘Granny Smith’ on M 9) growing interjacently and alternating between herbicide-damaged main crop
trees was affected. Respective to the position of the nine AP-infected and glyphosate-treated cut stumps, four sections in
the orchard were defined, from which a total of 122 trees was sampled and analysed using qualitative real-time PCR for detection
of AP phytoplasma. The pathogen was found in 71.4% of ‘Red Chief’ trees with severe herbicide damage and 18.8% of trees with
partial herbicide damage. None of the 31 investigated pollinators was AP-infected. Our data indicate that root connections
seem to play a role for the spread of AP phytoplasma at least in older orchards and between trees on vigorous rootstocks. 相似文献