Aphanomyces astaci, the causal agent of the crayfish plague, has recently been confirmed to infect also freshwater-inhabiting crabs. We experimentally tested the resistance of freshwater shrimps, another important decapod group inhabiting freshwaters, to this pathogen. We exposed individuals of two Asian shrimp species, Macrobrachium dayanum and Neocaridina davidi, to zoospores of the pathogen strain isolated from Procambarus clarkii, a known A. astaci carrier likely to get into contact with shrimps. The shrimps were kept in separate vessels up to seven weeks; exuviae and randomly chosen individuals were sampled throughout the experiment. Shrimp bodies and exuviae were tested for A. astaci presence by a species-specific quantitative PCR. The results were compared with amounts of A. astaci DNA in an inert substrate to distinguish potential pathogen growth in live specimens from persisting spores or environmental DNA attached to their surface. In contrast to susceptible crayfish Astacus astacus, we did not observe mortality of shrimps. The amount of detected pathogen DNA was decreasing steadily in the inert substrate, but it was still detectable several weeks after zoospore addition, which should be considered in studies relying on molecular detection of A. astaci. Probably due to moulting, the amount of A. astaci DNA was decreasing in N. davidi even faster than in the inert substrate. In contrast, high pathogen DNA levels were detected in some non-moulting individuals of M. dayanum, suggesting that A. astaci growth may be possible in tissues of this species. Further experiments are needed to test for the potential of long-term A. astaci persistence in freshwater shrimp populations.

• Klíčová slova
• Aphanomyces astaci, Crayfish plague, Freshwater shrimp, Host range, Pathogen transmission,
• MeSH
• Aphanomyces genetika   fyziologie   MeSH
• Decapoda (Crustacea) genetika   mikrobiologie   MeSH
• interakce hostitele a patogenu * MeSH
• odolnost vůči nemocem genetika   MeSH
• Palaemonidae genetika   mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Classical virulence analysis is based on discovering virulence phenotypes of isolates with regard to a composition of resistance genes in a differential set of host genotypes. With such a vision, virulence phenotypes are usually treated in a genetic manner as one of two possible alleles, either virulence or avirulence in a binary locus. Therefore, population genetics metrics and methods have become prevailing tools for analyzing virulence data at multiple loci. However, a basis for resolving binary virulence phenotypes is infection type (IT) data of host-pathogen interaction that express functional traits of each specific isolate in a given situation (particular host, environmental conditions, cultivation practice, and so on). IT is determined by symptoms and signs observed (e.g., lesion type, lesion size, coverage of leaf or leaf segments by mycelium, spore production and so on), and assessed by IT scores at a generally accepted scale for each plant-pathogen system. Thus, multiple IT profiles of isolates are obtained and can be subjected to analysis of functional variation within and among operational units of a pathogen. Such an approach may allow better utilization of the information available in the raw data, and reveal a functional (e.g., environmental) component of pathogen variation in addition to the genetic one. New methods for measuring functional variation of plant-pathogen interaction with IT data were developed. The methods need an appropriate assessment scale and expert estimations of dissimilarity between IT scores for each plant-pathogen system (an example is presented). Analyses of a few data sets at different hierarchical levels demonstrated discrepancies in results obtained with IT phenotypes versus binary virulence phenotypes. The ability to measure functional IT-based variation offers promise as an effective tool in the study of epidemics caused by plant pathogens.

• Klíčová slova
• analytical and theoretical plant pathology, ecology and epidemiology, genetics and resistance, population biology,
• MeSH
• analýza dat * MeSH
• interakce hostitele a patogenu MeSH
• nemoci rostlin * mikrobiologie   MeSH
• rostliny MeSH
• virulence MeSH
• Publikační typ
• časopisecké články MeSH

The European race of the ascomycetous species Gremmeniella abietina (Lagerberg) Morelet includes causal agents of shoot blight and stem canker of several conifers in Europe and North America, which are known to host a diverse virome. GaRV6 is the latest and sixth mycovirus species reported within G. abietina. Before its description, one victorivirus and one gammapartitivirus species were described in biotype A, two mitoviruses in both biotypes A and B and a betaendornavirus in biotype B. Possible phenotypic changes produced by mycoviruses on G. abietina mycelial growth have been reported in Spanish mitovirus-free and GaRV6-hosting G. abietina isolates, which had higher growth rates at the optimal temperature of 15 °C, but no other major differences have been observed between partitivirus-like dsRNA and dsRNA-free isolates. In this review, we reappraise the diversity of viruses found in G. abietina so far, and their relevance in clarifying the taxonomy of G. abietina. We also provide evidence for the presence of two new viruses belonging to the families Fusariviridae and Endornaviridae in Spanish isolates.

• Klíčová slova
• Brunchorstia pinea, conifers, dsRNA, evolution, mycovirus, phylogeny, ssRNA,
• MeSH
• Ascomycota virologie   MeSH
• biodiverzita * MeSH
• cévnaté rostliny mikrobiologie   MeSH
• mykoviry klasifikace   izolace a purifikace   MeSH
• nemoci rostlin mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Geografické názvy
• Evropa MeSH
• Severní Amerika MeSH

Anticipating how epidemics will spread across landscapes requires understanding host dispersal events that are notoriously difficult to measure. Here, we contrast host and virus genetic signatures to resolve the spatiotemporal dynamics underlying geographic expansions of vampire bat rabies virus (VBRV) in Peru. Phylogenetic analysis revealed recent viral spread between populations that, according to extreme geographic structure in maternally inherited host mitochondrial DNA, appeared completely isolated. In contrast, greater population connectivity in biparentally inherited nuclear microsatellites explained the historical limits of invasions, suggesting that dispersing male bats spread VBRV between genetically isolated female populations. Host nuclear DNA further indicated unanticipated gene flow through the Andes mountains connecting the VBRV-free Pacific coast to the VBRV-endemic Amazon rainforest. By combining Bayesian phylogeography with landscape resistance models, we projected invasion routes through northern Peru that were validated by real-time livestock rabies mortality data. The first outbreaks of VBRV on the Pacific coast of South America could occur by June 2020, which would have serious implications for agriculture, wildlife conservation, and human health. Our results show that combining host and pathogen genetic data can identify sex biases in pathogen spatial spread, which may be a widespread but underappreciated phenomenon, and demonstrate that genetic forecasting can aid preparedness for impending viral invasions.

• Klíčová slova
• Desmodus, forecasting, sex bias, spatial dynamics, zoonotic disease,
• MeSH
• Bayesova věta MeSH
• biologická evoluce * MeSH
• Chiroptera virologie   MeSH
• genom virový MeSH
• interakce hostitele a patogenu * MeSH
• mikrosatelitní repetice genetika   MeSH
• roční období MeSH
• typy dědičnosti genetika   MeSH
• virus vztekliny genetika   MeSH
• vzteklina epidemiologie   MeSH
• zeměpis MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Peru epidemiologie   MeSH

This study aimed to evaluate the potential pathogenicity and antibiotic resistance of 31 environmental Vibrio isolates obtained from surface water in southern and eastern Slovakia. Isolates were identified as Vibrio cholerae non-O1/non-O139 and Vibrio metschnikovii by biochemical tests, MALDI biotyping, and 16S RNA gene sequencing. Analysis of the susceptibility to 13 antibacterial agents showed susceptibility of all isolates to ciprofloxacin, trimethoprim/sulfamethoxazole, chloramphenicol, gentamicin, imipenem, tetracyclin, and doxycycline. We recorded high rates of resistance to β-lactams and streptomycin. Investigation of antibiotic resistance showed five different antibiotic profiles with resistance to antibacterials from three classes, but no multidrug resistance was observed. The investigation of the pathogenic potential of V. cholerae isolates showed that neither the cholera toxin coding gene ctxA nor the genes zot (zonula occludens toxin), ace (accessory cholera toxin), and tcpA (toxin-coregulated pilus) were present in any of 31 isolated samples. Gene ompU (outer membrane protein) was confirmed in 80% and central regulatory protein-coding gene toxR in 71% of V. cholerae isolates, respectively. A high prevalence of the hemolysin coding gene hlyA in all V. cholerae was observed. The data point toward the importance of systematic monitoring and comparative studies of potentially pathogenic vibrios in European countries.

• Klíčová slova
• Antibiotic resistance, MALDI biotyping, Vibrio cholerae non-O1/non-O139, Vibrio metschnikovii, Virulence,
• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence * MeSH
• bakteriální proteiny genetika   MeSH
• mikrobiologie vody * MeSH
• sladká voda mikrobiologie   MeSH
• Vibrio účinky léků   genetika   patogenita   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Slovenská republika MeSH
• Názvy látek
• antibakteriální látky MeSH
• bakteriální proteiny MeSH

Phytophthora is arguably one of the most damaging genera of plant pathogens. This pathogen is well suited to transmission via the international plant trade, and globalization has been promoting its spread since the 19th century. Early detection is essential for reducing its economic and ecological impact. Here, a shotgun proteomics approach was utilized for Phytophthora analysis. The collection of 37 Phytophthora isolates representing 12 different species was screened for species-specific peptide patterns. Next, Phytophthora proteins were detected in planta, employing model plants Solanum tuberosum and Hordeum vulgare. Although the evolutionarily conserved sequences represented more than 10% of the host proteome and limited the pathogen detection, the comparison between qPCR and protein data highlighted more than 300 protein markers, which correlated positively with the amount of P. infestans DNA. Finally, the analysis of P. palmivora response in barley revealed significant alterations in plant metabolism. These changes included enzymes of cell wall metabolism, ROS production, and proteins involved in trafficking. The observed root-specific attenuation in stress-response mechanisms, including the biosynthesis of jasmonates, ethylene and polyamines, and an accumulation of serotonin, provided the first insight into molecular mechanisms behind this particular biotic interaction.

• Klíčová slova
• Hordeum vulgare, P. infestans, P. palmivora, Phytophthora, Solanum tuberosum, leaf inoculation, proteomics,
• MeSH
• chromatografie kapalinová MeSH
• fyziologický stres MeSH
• hmotnostní spektrometrie MeSH
• ječmen (rod) enzymologie   metabolismus   mikrobiologie   MeSH
• listy rostlin metabolismus   mikrobiologie   MeSH
• metabolické sítě a dráhy MeSH
• nemoci rostlin mikrobiologie   MeSH
• peptidy metabolismus   MeSH
• Phytophthora infestans genetika   izolace a purifikace   MeSH
• polymerázová řetězová reakce MeSH
• proteom metabolismus   MeSH
• proteomika MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rostlinné proteiny metabolismus   MeSH
• Solanum tuberosum metabolismus   mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• peptidy MeSH
• proteom MeSH
• reaktivní formy kyslíku MeSH
• rostlinné proteiny MeSH

Numerous oomycetes colonise the crayfish cuticle, the best known being the crayfish plague pathogen Aphanomyces astaci. Although other oomycetes associated with crayfish complicate the isolation and molecular detection of A. astaci, their diversity is little known. To improve this knowledge, we analysed 95 oomycete isolates obtained during attempts to isolate A. astaci from crayfish presumably infected by this pathogen. We characterized the isolates morphologically and by sequencing of the nuclear internal transcribed spacer (ITS) region. We identified 13 taxa by molecular analysis. Ten of them were assigned to five genera; the remaining three were affiliated with the order Saprolegniales but could not be reliably assigned to any genus. Morphological identification to species level was only possible for 15 % of isolates; all corresponded to Saprolegnia ferax, which was confirmed by ITS sequencing. The most frequently isolated species were S. ferax and Saprolegnia australis. Only seven isolates of A. astaci were obtained, all from one disease outbreak. We show that oomycete cultures obtained as by-products of parasite isolation are valuable for oomycete diversity studies, but morphological identification may uncover only a fraction of their diversity. Further, we show that crayfish may be frequently associated with potentially serious parasites of other organisms.

• Klíčová slova
• Aphanomyces astaci, Internal transcribed spacer, Oogonia, Oomycota, Pathogen vectors, Sequencing,
• Publikační typ
• časopisecké články MeSH

Phytophthora pseudosyringae is a self-fertile pathogen of woody plants, particularly associated with tree species from the genera Fagus, Notholithocarpus, Nothofagus and Quercus, which is found across Europe and in parts of North America and Chile. It can behave as a soil pathogen infecting roots and the stem collar region, as well as an aerial pathogen infecting leaves, twigs and stem barks, causing particular damage in the United Kingdom and western North America. The population structure, migration and potential outcrossing of a worldwide collection of isolates were investigated using genotyping-by-sequencing. Coalescent-based migration analysis revealed that the North American population originated from Europe. Historical gene flow has occurred between the continents in both directions to some extent, yet contemporary migration is overwhelmingly from Europe to North America. Two broad population clusters dominate the global population of the pathogen, with a subgroup derived from one of the main clusters found only in western North America. Index of association and network analyses indicate an influential level of outcrossing has occurred in this preferentially inbreeding, homothallic oomycete. Outcrossing between the two main population clusters has created distinct subgroups of admixed individuals that are, however, less common than the main population clusters. Differences in life history traits between the two main population clusters should be further investigated together with virulence and host range tests to evaluate the risk each population poses to natural environments worldwide.

• Klíčová slova
• forest pathogen, homothallic, invasive pathogen, migration, outcrossing, population genetics,
• MeSH
• fylogeografie MeSH
• lidé MeSH
• nemoci rostlin MeSH
• Phytophthora * genetika   MeSH
• rostliny MeSH
• stromy MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Sarcina spp. has been isolated from the gastrointestinal tracts of diverse mammalian hosts. Their presence is often associated with host health complications, as is evident from many previously published medical case reports. However, only a handful of studies have made proper identification. Most other identifications were solely based on typical Sarcina-like morphology without genotyping. Therefore, the aim of this work was culture detection and the taxonomic classification of Sarcina isolates originating from different mammalian hosts. Sarcina-like colonies were isolated and collected during cultivation analyses of animal fecal samples (n = 197) from primates, dogs, calves of domestic cattle, elephants, and rhinoceroses. The study was carried out on apparently healthy animals kept in zoos or by breeders in the Czech Republic and Slovakia. Selected isolates were identified and compared using 16S rRNA gene sequencing and multi-locus sequence analysis (MLSA; Iles, pheT, pyrG, rplB, rplC, and rpsC). The results indicate the taxonomic variability of Sarcina isolates. S. ventriculi appears to be a common gut microorganism in various captive primates. In contrast, a random occurrence was also recorded in dogs. However, dog isolate N13/4e could represent the next potential novel Sarcina taxonomic unit. Also, a potentially novel Sarcina species was found in elephants, with occurrences in all tested hosts. S. maxima isolates were detected rarely, only in rhinoceroses. Although Sarcina bacteria are often linked to lethal diseases, our results indicate that Sarcina spp. appear to be a common member of the gut microbiota and seem to be an opportunistic pathogen. Further characterization and pathogenic analyses are required.

• Klíčová slova
• Sarcina spp., animals, cultivation, mammalians, microbiota, taxonomy,
• Publikační typ
• časopisecké články MeSH

The psychrophilic (cold-loving) fungus Pseudogymnoascus destructans was discovered more than a decade ago to be the pathogen responsible for white-nose syndrome, an emerging disease of North American bats causing unprecedented population declines. The same species of fungus is found in Europe but without associated mortality in bats. We found P. destructans was infected with a mycovirus [named Pseudogymnoascus destructans partitivirus 1 (PdPV-1)]. The virus is bipartite, containing two double-stranded RNA (dsRNA) segments designated as dsRNA1 and dsRNA2. The cDNA sequences revealed that dsRNA1 dsRNA is 1,683 bp in length with an open reading frame (ORF) that encodes 539 amino acids (molecular mass of 62.7 kDa); dsRNA2 dsRNA is 1,524 bp in length with an ORF that encodes 434 amino acids (molecular mass of 46.9 kDa). The dsRNA1 ORF contains motifs representative of RNA-dependent RNA polymerase (RdRp), whereas the dsRNA2 ORF sequence showed homology with the putative capsid proteins (CPs) of mycoviruses. Phylogenetic analyses with PdPV-1 RdRp and CP sequences indicated that both segments constitute the genome of a novel virus in the family Partitiviridae. The purified virions were isometric with an estimated diameter of 33 nm. Reverse transcription PCR (RT-PCR) and sequencing revealed that all US isolates and a subset of Czech Republic isolates of P. destructans were infected with PdPV-1. However, PdPV-1 appears to be not widely dispersed in the fungal genus Pseudogymnoascus, as non-pathogenic fungi P. appendiculatus (1 isolate) and P. roseus (6 isolates) tested negative. P. destructans PdPV-1 could be a valuable tool to investigate fungal biogeography and the host-pathogen interactions in bat WNS.

• MeSH
• Ascomycota izolace a purifikace   virologie   MeSH
• Chiroptera mikrobiologie   MeSH
• dvouvláknová RNA genetika   izolace a purifikace   MeSH
• fylogeneze MeSH
• mykoviry genetika   fyziologie   ultrastruktura   MeSH
• RNA virová genetika   izolace a purifikace   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• virové proteiny chemie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Česká republika MeSH
• Spojené státy americké MeSH
• Názvy látek
• dvouvláknová RNA MeSH
• RNA virová MeSH
• virové proteiny MeSH