237 research outputs found
Chromosomes, karyotype analysis, chromosome rearrangements in fungi
In this review the organization of fungal chromosomes and the methods used for karyotype analysis are briefly summarized. The role of chromosome rearrangement, supernumerary chromosomes and repeated DNA sequences in the genetic change of fungi is evaluated
Role of MAP Kinase Signaling in Secondary Metabolism and Adaptation to Abiotic/Fungicide Stress in Fusarium
First evidence of Candidatus Neoehrlichia mikurensis in Hungary
Altogether 2004 Ixodes ricinus ticks, from 37 places in Hungary, were analysed in pools with a recently developed multiplex real-time PCR for the presence of Candidatus Neoehrlichia mikurensis and for other representatives of the genus. Ca. Neoehrlichia mikurensis was identified in nine sampling sites, indicating three separated endemic regions along the borders of Hungary. In addition, results of samples from seven places (except for the western part of the country) were positive in the genus-specific (Ca. Neoehrlichia sp.) PCR, but were negative for Ca. Neoehrlichia mikurensis
Synanthropic rodents and their ectoparasites as carriers of a novel haemoplasma and vector-borne, zoonotic pathogens indoors
Interspecies virus transfer via protoplast fusions between Fusarium poae and black Aspergillus strains
Similarities between the genome organisation of dsRNA mycoviruses and dsRNA patterns in different fungal species suggest a relatedness between these viruses, which could be the result of co-evolved infections or of interspecies transfer. Such interspecies transfer between species is suggested by our observation of transfer and maintenance of mycoviral dsRNAs between Fusarium and Aspergillus via protoplast fusion
Quantification of the relationship between the environment and Fusarium head blight, Fusarium pathogen density, and mycotoxins in winter wheat in Europe
Measurements of local environmental conditions,
intensity of Fusarium head blight (FHB) in
wheat spikes, biomass of Fusarium graminearum, F.
culmorum, and F. poae (pathogens causing FHB) and
concentration of the mycotoxins deoxynivalenol
(DON) and nivalenol (NIV) in harvested wheat grain
were obtained in a total of 150 location-years, originating
in three European countries (Hungary, Ireland,
United Kingdom) from 2001 to 2004. Through
window-pane methodology, the length and starting
time of temporal windows where the environmental
variables were significantly associated with the biological
variables were identified. Window lengths of 5
to 30 days were evaluated, with starting times from
18 days before anthesis to harvest. Associations were
quantified with nonparametric Spearman correlation
coefficients. All biological variables were significantly
associated with at least one evaluated environmental
variable (P≤0.05). Moisture-related variables (e.g.,
average relative humidity, hours of relative humidity above 80%) had the highest positive correlations with
the biological variables, but there also was a significant
negative correlation between average temperature
and several biological variables. When significant correlations
were found, they were generally for all window
lengths, but for a limited number of window start
times (generally before anthesis for disease index and
after anthesis for the toxins and late-season fungal
biomasses). Semi-partial Spearman correlation coefficients
were used to evaluate the relationship between
the environmental variables and the concentration of
DON and NIV after the effects of FHB intensity and
fungal biomass on the mycotoxins were removed.
Significant semi-partial correlations were found between
relative humidity variables and DON, and between
temperature and relative humidity variables and
NIV for time windows that started after anthesis (and
not for any earlier time windows). Results confirm that
the environment influences disease, fungal biomass,
and mycotoxin production, and help refine the time
windows where the association is greatest. However,
variability in the relationships was high, indicating
that no single environmental variable is sufficient for
prediction of disease or mycotoxin contamination
Influence of the biotope on the tick infestation of cattle and on the tick-borne pathogen repertoire of cattle ticks in Ethiopia
Background:
The majority of vector-borne infections occur in the tropics, including Africa, but molecular eco-
epidemiological studies are seldom reported from these regions. In particular, most previously published data on ticks in
Ethiopia focus on species distribution, and only a few molecular studies on the occurrence of tick-borne pathogens or on
ecological factors influencing these. The present study was undertaken to evaluate, if ticks collected from cattle in different
Ethiopian biotopes harbour (had access to) different pathogens.
Methods:
In South-Western Ethiopia 1032 hard ticks were removed from cattle grazing in three kinds of tick biotopes. DNA
was individually extracted from one specimen of both sexes of each tick species per cattle. These samples were molecularly
analysed for the presence of tick-borne pathogens.
Results:
Amblyomma variegatum
was significantly more abundant on mid highland, than on moist highland.
Rhipicephalus
decoloratus
was absent from savannah lowland, where virtually only
A. cohaerens
was found. In the ticks
Coxiella burnetii
had
the highest prevalence on savannah lowland. PCR positivity to
Theileria
spp. did not appear to depend on the biotope, but
some genotypes were unique to certain tick species. Significantly more
A. variegatum
specimens were rickettsia-positive,
than those of other tick species. The presence of rickettsiae (
R. africae
) appeared to be associated with mid highland in case
of
A. variegatum
and
A. cohaerens
. The low level of haemoplasma positivity seemed to be equally distributed among the tick
species, but was restricted to one biotope type.
Conclusions:
The tick biotope, in which cattle are grazed, will influence not only the tick burden of these hosts, but also the
spectrum of pathogens in their ticks. Thus, the presence of pathogens with alternative (non-tick-borne) transmission routes,
with transstadial or with transovarial transmission by ticks appeared to be associated with the biotope type, with the tick
species, or both, respectively
Birds as potential reservoirs of tick-borne pathogens: first evidence of bacteraemia with Rickettsia helvetica
Seasonally biased or single-habitat sampling is not informative on the real prevalence of Dermacentor reticulatus-borne rickettsiae — A pilot study
Dermacentor reticulatus is a tick species of high medical and veterinary importance, emerging in several parts of Europe. Up to now most studies focusing on zoonotic rickettsiae in D. reticulatus were based on ticks collected in a limited part of the questing period, and did not take into account the potential seasonal variations in the rate of infection with tick-borne rickettsiae. The aim of the present study was to investigate the latter phenomenon, i.e. to screen D. reticulatus adults, collected monthly in two urban habitats of Budapest, for the presence of three zoonotic Rickettsia spp. Altogether 852 D. reticulatus adults were collected, which showed significantly similar seasonal activity in the two evaluated habitats. Among the 413 molecularly analysed ticks, R. helvetica-infected D. reticulatus were only collected during autumn in habitat-1, in contrast to habitat-2. The overall prevalence of R. raoultii in D. reticulatus adults was significantly higher in habitat-1 than in habitat-2. In addition, the seasonal distribution of R. raoultii-infected ticks was different between the two habitats (in habitat-2 significantly more R. raoultii-infected ticks were collected in the autumn, in comparison with winter and spring). Rickettsia slovaca was not detected in any of the molecularly analysed ticks. The results clearly indicate that a single-time or seasonally biased collection of D. reticulatus adults and their subsequent molecular analysis may not be informative on the real prevalence of rickettsiae. This is because the availability/ activity of infected ticks shows significant seasonal fluctuations, both within and between habitats. Instead, for screening D. reticulatus-borne rickettsiae, it is important to collect monthly samples and then to assess seasonal prevalence and actual habitat-associated eco-epidemiological risks
Diversity of Haemaphysalis-associated piroplasms of ruminants in Central-Eastern Europe, Hungary
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