Rotaviruses (RVs) are classified into nine species or groups (RVA-RVD and RVF-RVJ). RVA, RVB and RVC are well-recognized as etiological agents of enteric disease on swine farms and have been identified in all countries with a relevant pork production. Contrarily, RVH has only been identified on swine farms from Japan and more recently from Brazil, USA, South Africa and Vietnam but not yet in Europe. The occurrence of RVH was investigated in 103 Spanish pig herds. Nine farms were positive and we achieved a complete nucleotide sequences in three isolates while another RVH isolate was partially sequenced. Mean nucleotide identities with the RVH sequences available in GenBank ranged between 69.4% and 93.7%. Phylogenetically, all genomic segments of Spanish RVH isolate clustered closely with other porcine RVH strains but were distantly related to human RVH as well as bat RVH strain. To the best of our knowledge, this is the first report of RVH on swine farms in Europe including its characterization by means of complete genome sequencing.
A retrospective evaluation of PEDV positive samples recovered in Spain before and after the re-emergence of this coronavirus in several European countries was carried out. We described for the first time recombinant SeCoV circulating in Spain between 1993 and 2014 and its misidentification as PEDV when diagnostic assays based on the S-protein or S-gene of the PEDV were used. The complete S-gene sequence of 7 Spanish SeCoV and 30 PEDV Spanish isolates was phylogenetically analysed including the S-gene sequences of the three SeCoV and a representative selection of the PEDV strains with complete genome sequences available in the GenBank. The tree showed a common ancestor for the S-gene of the PEDV and SeCoV, but no evolution from any known PEDV clade was shown for the SeCoV strains. Moreover, complete genome sequences were obtained from 23 PEDV strains recovered in Spanish swine farms since 2014. The phylogenetic tree showed the INDEL type genogroup of these Spanish strains, supporting the lower pathogenicity of this genogroup since no significant economic losses were reported in the affected Spanish swine farms. Four subgroups were detected among PEDV strains in Spain, closely related to the recent European strains. Moreover, eight of the most recent Spanish PEDV isolates formed a subclade together with three European strains from 2015, showing a new evolution branch with a recombinant virus.
The screening for alternatives to antibiotics is an urgent need for the pharmaceutical industry. One of these alternatives seems to be the citrus fruit extracts, which are showing a significant antibacterial activity against Gram-negative and Gram-positive bacteria. One of these citrus extracts, named BIOCITRO®, is assessed in this study to elucidate its bacteriostatic and bactericidal effect and its mode of action on the important pathogens Campylobacter coli, C. jejuni, Escherichia coli, Salmonella enterica ssp. enterica, Clostridium difficile, C. perfringens, and Staphylococcus aureus. For most of the strains tested of these bacteria the product was bactericidal as well as bacteriostatic at the same concentration, and the minimum bactericidal concentrations ranged from 16 to 256 μg/mL. Regarding the mode of action, important changes in the permeability, structure, composition and morphology of the bacterial envelope were evidenced using flow cytometry, Fourier transform infrared spectroscopy and scanning electron microscopy. The main effect of the product was found over carbohydrates and polysaccharides, inducing the release of microvesicles by the cells in addition to other specific effects. During the study, the techniques used were evaluated to clarify their contribution to the knowledge of the mode of action of the product. The survival test elucidated whether the modifications displayed using other techniques affected the viability of the cells or on the contrary, the cells remained viable even with evident changes in their structure, composition or morphology. Flow cytometry showed that for some strains the proportion of cells detected with altered membrane permeability were higher than the number of non-viable cells, and therefore the damage did not affect the viability of some cells. On the contrary, some cells observed using scanning electron microscopy with no apparent damage, were demonstrated non-viable using the survival test, making this technique indispensable in studies of the mode of action of antimicrobials to make a correct interpretation of the data from other techniques.
Background Accurate screening of new alternative antimicrobial compounds is essential for their use to control pathogens in swine production due to the replacement of antibiotics and zinc oxide. Most in vitro studies have separately reported the antimicrobial activity of organic acids and essential oils (EOs) using diverse methods for susceptibility testing. In addition, in vitro outcomes can help in the selection of the suitable antimicrobial compound and effective combinations of these compounds in the control of pathogens of interest in pork production. Therefore, the aim of this study is to determinate the antibacterial activity of six organic acids and six EOs against Escherichia coli, Salmonella spp. and Clostridium perfringens isolates, some of them multi-resistant to antibiotics, from swine origin. The synergistic effects between the products with higher activity for each bacteria were also calculated. Results All products tested showed activity against at least one bacterial species, except for black pepper EO. The results showed that formic acid with the shortest chain length was the most effective against E. coli and Salmonella spp., while the sodium salt of coconut fatty acid distillates with long chain acids was the most effective against C. perfringens. The susceptibility of isolates tested to EOs was similar, a result that demonstrates a similar activity of these products against phylogenetically unrelated pathogens. In addition, an additive effect was shown for carvacrol-oregano EO for E. coli, formic acid-carvacrol and formic acid-thymol for Salmonella spp. and carvacrol-cinamaldehyde for C. perfringens. Conclusions The susceptibility of isolates to EOs was similar, a result that demonstrates a similar activity of these products against phylogenetically unrelated pathogens in contrast to organic acids. In addition, an additive effect was shown for several combinations of these compounds.
BACKGROUND:Diarrhoea is a major cause of death in neonate pigs and most of the viruses that cause it are RNA viruses. Next Generation Sequencing (NGS) deeply characterize the genetic diversity among rapidly mutating virus populations at the interspecific as well as the intraspecific level. The diversity of RNA viruses present in faeces of neonatal piglets suffering from diarrhoea in 47 farms, plus 4 samples from non-diarrhoeic piglets has been evaluated by NGS. Samples were selected among the cases submitted to the Veterinary Diagnostic Laboratories of Infectious Diseases of the Universitat Autònoma de Barcelona (Barcelona, Spain) and Universidad de León (León, Spain). RESULTS:The analyses identified the presence of 12 virus species corresponding to 8 genera of RNA viruses. Most samples were co-infected by several viruses. Kobuvirus and Rotavirus were more commonly reported, with Sapovirus, Astrovirus 3, 4 and 5, Enterovirus G, Porcine epidemic diarrhoea virus, Pasivirus and Posavirus being less frequently detected. Most sequences showed a low identity with the sequences deposited in GenBank, allowing us to propose several new VP4 and VP7 genotypes for Rotavirus B and Rotavirus C. CONCLUSIONS:Among the cases analysed, Rotaviruses were the main aetiological agents of diarrhoea in neonate pigs. Besides, in a small number of cases Kobuvirus and Sapovirus may also have an aetiological role. Even most animals were co-infected in early life, the association with enteric disease among the other examined viruses was unclear. The NGS method applied successfully characterized the RNA virome present in faeces and detected a high level of unreported intraspecific diversity.
Brachyspira hyodysenteriae is the main etiological agent of swine dysentery (SD). Nowadays, treatment and control of SD is increasingly difficult due to the emergence of antimicrobial resistance together with the restrictions on the use of antibiotics in veterinary practice. The aim of this study was to evaluate, as an alternative in the control of this disease, the antimicrobial activity and the main mechanism of action of BIOCITRO, a citrus extract commercialized as raw material and used as feed additive, against B. hyodysenteriae. Ten isolates of B. hyodysenteriae were used to assess the minimum inhibitory and minimum bactericidal concentrations (MIC and MBC) of BIOCITRO by broth microdilution method. Moreover, stationary phase cultures of two B. hyodysenteriae strains were subjected for 90min to four different concentrations of BIOCITRO and compared with the untreated controls by flow cytometry (FC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that BIOCITRO has a relevant bacteriostatic and bactericidal effect against B. hyodysenteriae with MIC and MBC values ranging from 32 to 128partspermillion (ppm). It induces damage in at least 35% and 76% of the bacterial cells when exposed to 128 and 256ppm of BIOCITRO respectively as revealed by the intake of propidium iodide by FC. Relevant changes in the structure of the bacterial cells were observed by SEM and confirmed by FTIR. According to these results, BIOCITRO seems to be a satisfactory alternative to the use of antibiotics in the control of SD.
Porcine epidemic diarrhea (PED) is an enteric disease in swine caused by an alphacoronavirus. It affects swine of all ages causing acute diarrhoea and can lead to severe dehydration and death in suckling piglets. Being recognized for the first time in Europe and Asia during the seventies and the eighties, respectively, it has remained a relevant cause of diarrhea outbreaks in Asia for years and to the present. It has become a major concern in swine production since 2013 when the virus was detected for first time in the USA and in other American countries causing a high number of pig deaths and significant economic losses. The present review aims at approaching the reader to the state of the art of PED giving answer to some of the most recent questions which have arisen related to this disease.
The Pleistocene climatic oscillations promoted the diversification in avian species during the last glacial period. The red‐legged partridge (Alectoris rufa, Family Phasianidae) has a large natural distribution extending from the Mediterranean to humid temperate zones. However, the genetic structure for this species is unknown. The present study investigates the phylogeography, genetic structure and demographic history of A. rufa across its distribution, employing both mitochondrial DNA control region sequences and nuclear microsatellite loci. Our results propose that this species was greatly affected by Pleistocene glaciations. The mismatch analyses suggest that the current populations resulted from post‐glacial expansion and subsequent differentiation resulting in five diagnosable genetic clusters: Southwestern, Central‐eastern, Northwestern, Balearic and French and Italian. Further, we found evidence of three glacial refugia within the currently recognized Iberian glacial refugium. The intraspecific structure revealed by both maternal and biparental phylogeographic analyses was not resolved in the phylogenetic analyses. Based on all considerations, we recommended that five management units be recognized.
This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species.
This article documents the addition of 283 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Agalinis acuta; Ambrosia artemisiifolia; Berula erecta; Casuarius casuarius; Cercospora zeae-maydis; Chorthippus parallelus; Conyza canadensis; Cotesia sesamiae; Epinephelus acanthistius; Ficedula hypoleuca; Grindelia hirsutula; Guadua angustifolia; Leucadendron rubrum; Maritrema novaezealandensis; Meretrix meretrix; Nilaparvata lugens; Oxyeleotris marmoratus; Phoxinus neogaeus; Pristomyrmex punctatus; Pseudobagrus brevicorpus; Seiridium cardinale; Stenopsyche marmorata; Tetranychus evansi and Xerus inauris. These loci were cross-tested on the following species: Agalinis decemloba; Agalinis tenella; Agalinis obtusifolia; Agalinis setacea; Agalinis skinneriana; Cercospora zeina; Cercospora kikuchii; Cercospora sorghi; Mycosphaerella graminicola; Setosphaeria turcica; Magnaporthe oryzae; Cotesia flavipes; Cotesia marginiventris; Grindelia Xpaludosa; Grindelia chiloensis; Grindelia fastigiata; Grindelia lanceolata; Grindelia squarrosa; Leucadendron coniferum; Leucadendron salicifolium; Leucadendron tinctum; Leucadendron meridianum; Laodelphax striatellus; Sogatella furcifera; Phoxinus eos; Phoxinus rigidus; Phoxinus brevispinosus; Phoxinus bicolor; Tetranychus urticae; Tetranychus turkestani; Tetranychus ludeni; Tetranychus neocaledonicus; Tetranychus amicus; Amphitetranychus viennensis; Eotetranychus rubiphilus; Eotetranychus tiliarium; Oligonychus perseae; Panonychus citri; Bryobia rubrioculus; Schizonobia bundi; Petrobia harti; Xerus princeps; Spermophilus tridecemlineatus and Sciurus carolinensis.
The mechanisms involved in desiccation tolerance of lichens and their photobionts are still poorly understood. To better understand these mechanisms we have studied dehydration rate and desiccation time in Trebouxia, the most abundant chlorophytic photobiont in lichen. Our findings indicate that the drying rate has a profound effect on the recovery of photosynthetic activity of algae after rehydration, greater than the effects of desiccation duration. The basal fluorescence (F'(o)) values in desiccated algae were significantly higher after rapid dehydration, than after slow dehydration, suggesting higher levels of light energy dissipation in slow-dried algae. Higher values of PSII electron transport were recovered after rehydration of slow-dried Trebouxia erici compared to rapid-dried algae. The main component of non-photochemical quenching after slow dehydration was energy dependent (q (E)), whereas after fast dehydration it was photoinhibition (q (I)). Although q (E) seems to play a role during desiccation recovery, no significant variations were detected in the xanthophyll cycle components. Desiccation did not affect PSI functionality. Classical antioxidant activities like superoxide dismutase or peroxidase decreased during desiccation and early recovery. Dehydrins were detected in the lichen-forming algae T. erici and were constitutively expressed. There is probably a minimal period required to develop strategies which will facilitate transition to the desiccated state in this algae. In this process, the xanthophyll cycle and classical antioxidant mechanisms play a very limited role, if any. However, our results indicate that there is an alternative mechanism of light energy dissipation during desiccation, where activation is dependent on a sufficiently slow dehydration rate.
The genus Festuca comprises approximately 450 species and is widely distributed around the world. The Iberian Penninsula, with more than 100 taxa colonizing very diverse habitats, is one of its main centers of diversification. This study was conducted to assess molecular genetic variation and genetic relatedness among 91 populations of 31 taxa of Iberian fescues, based on several molecular markers (random amplified polymorphic DNA, amplified fragment length polymorphisms, and trnL sequences). The analyses showed the paraphyletic origin of the broad-leaved (subgenus Festuca , sections Scariosae and Subbulbosae, and subgenus Schedonorus ) and the fine-leaved fescues (subgenus Festuca, sections Aulaxyper, Eskia, and Festuca). Schedonorus showed a weak relationship with Lolium rigidum and appeared to be the most recent of the broad-leaved clade. Section Eskia was the most ancient and Festuca the most recent of the fine-leaved clade. Festuca and Aulaxyper were the most related sections, in concordance with their taxonomic affinities. All taxa grouped into their sections, except F. ampla and F. capillifolia (section Festuca), which appeared to be more closely related to Aulaxyper and to a new independent section, respectively. Most populations clustered at the species level, but some subspecies and varieties mixed their populations. This study demonstrated the value in combining different molecular markers to uncover hidden genetic relationships between populations of Festuca.
Amplified fragment length polymorphism (AFLP) DNA markers were used to characterize the genetic diversity and relationships in wild species of the genus Aegilops. Fifty populations, which included the species Aegilops biuncialis (UUMM), Ae. neglecta (UUMMNN), Ae. ovata (UUMM), Ae. ventricosa (DDNN) and Ae. triuncialis (UUCC) were selected. These populations are distributed in the Iberian peninsula and Balearic islands. Five AFLP selective primer combinations generated a total of 527 amplification products of which 517 (98.10%) detected polymorphisms. Aegilops neglecta showed the least variation in contrast with Ae. biuncialis that presented the highest degree of polymorphism. Genetic relationships within the populations were evaluated by generating a similarity matrix based on the Jaccard index. In the resulting phenogram Ae. ventricosa appears segregated from the other species, probably owing to the influence of the D genome. The species sharing the U genome are located in the main cluster. The branching pattern of the U genome group reflects the proximity of the species sharing the M genome. Ae. biuncialis and Ae. ovata are clearly separated suggesting that the super index system should be used to differentiate the M genomes of both species. The variation among populations within species in relation to their geographical origin and results previously obtained by the authors using biochemical and molecular markers are discussed.