RESUMO
Skin microbiomes in amphibians are complex systems that can be influenced by biotic and abiotic factors. In this study, we examined the effect of host species and environmental conditions on the skin bacterial and fungal microbiota of four obligate paedomorphic salamander species, commonly known as axolotls (Ambystoma andersoni, A. dumerilii, A. mexicanum, and A. taylori), all of them endemic to the Trans-Mexican Volcanic Belt. We found that despite their permanent aquatic lifestyle, these species present a host-specific skin microbiota that is distinct from aquatic communities. We identified skin-associated taxa that were unique to each host species and that differentiated axolotl species based on alpha and beta diversity metrics. Moreover, we identified a set of microbial taxa that were shared across hosts with high relative abundances across skin samples. Specifically, bacterial communities were dominated by Burkholderiales and Pseudomonadales bacterial orders and Capnodiales and Pleosporales fungal orders. Host species and environmental variables collectively explained more microbial composition variation in bacteria (R2 = 0.46) in comparison to fungi (R2 = 0.2). Our results contribute to a better understanding of the factors shaping the diversity and composition of skin microbial communities in Ambystoma. Additional studies are needed to disentangle the effects of specific host associated and environmental factors that could influence the skin microbiome of these endangered species.
Assuntos
Bactérias , Fungos , Microbiota , Pele , Animais , Pele/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , México , Fungos/classificação , Fungos/isolamento & purificação , Fungos/genética , Ambystoma mexicanum/microbiologia , Especificidade de Hospedeiro , Meio Ambiente , BiodiversidadeRESUMO
This study investigated the spatial distribution, parasite interactions, and affinities of Branchiura parasites according to macrohabitat and surface type on fish from the Araguari River, Amapá State, in the Brazilian Amazon. This study presents novel information on the interactions of branchiuran species with host fish, and how the morphology of their attachment structures is associated with different host surface morphologies, with and without scales. A total of 558 fish specimens of 26 species were collected, of which 109 fish (10 species) were parasitized by at least one branchiuran parasite; these were selected for further study. The parasites were collected from the buccal cavity, gills, fins, and integument of the host fish. Parasites with suction discs (Argulus) were mainly associated to hosts with small scales and no scales, while parasites with hooks (Dolops) were mainly associated to hosts with large scales. Overall, parasites with suction discs were more specialized per site than those with hooks.
Assuntos
Peixes , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Rios , Animais , Brasil , Peixes/parasitologia , Peixes/classificação , Rios/parasitologia , Doenças dos Peixes/parasitologia , Ecossistema , Arguloida/classificação , Arguloida/fisiologia , Arguloida/anatomia & histologiaRESUMO
Knowledge of parasite-host interactions is essential for understanding factors associated with the ecology and evolution of both groups. Some aspects, such as host size and phylogeny, as well as parasite specificity, are significant predictors that help unveil the parasite-host relationship. Thus, the goals of this study were: (1) to describe parasite diversity in regions of the Atlantic Forest; (2) to analyze which host characteristics can influence parasite richness of anuran's parasite component community; and (3) to investigate if the prevalence of parasite infection is related to specificity metrics (ecological and phylogenetic), number of infected hosts and parasite's abundance. We identified 49 parasite taxa, classified into three phyla: Nematoda, Acanthocephala, and Platyhelminthes. Supporting the existing literature, our findings corroborate the positive relationship between host size and parasite richness, further emphasizing the significance of this predictor. Parasite prevalence in the host community is related to the number of infected host species and parasite abundance, but not to phylogenetic and ecological specificity indices. This shows that parasite prevalence is strongly associated with infection opportunity, host sampling effort, and high parasite abundance.
Assuntos
Anuros , Biodiversidade , Florestas , Interações Hospedeiro-Parasita , Nematoides , Filogenia , Animais , Anuros/parasitologia , Nematoides/classificação , Brasil/epidemiologia , Acantocéfalos/classificação , Acantocéfalos/fisiologia , Acantocéfalos/isolamento & purificação , Prevalência , Helmintos/classificação , Helmintos/isolamento & purificação , Helmintos/genética , Especificidade de HospedeiroRESUMO
Non-typhoid Salmonella enterica causes salmonellosis illness, and this bacterium can contaminate food throughout the production chain, including those that are consumed as raw products. Salmonella enterica can adhere to and internalize into fresh produce such as cherry tomatoes. It has been reported that lytic bacteriophages (phages) can be used as a biocontrol agent in the agricultural field, being an alternative for the control of Salmonella in red meat, fish, lettuce, and cabbage. The aim of this study was to characterize the two phages present in the PHA46 cocktail to determine their morphology, genome, host range, and resistance to different temperatures and pHs values; and later evaluate their lytic activity to reduce the adherence to and internalization of Salmonella enterica serovars Newport and Typhimurium into cherry tomatoes. In addition, in this work, we also explored the effect of the PHA46 cocktail on the virulence of S. Newport-45 and S. Typhimurium SL1344, recovered from the interior of cherry tomatoes, on the lifespan of the animal model Caenorhabditis elegans. The nematode C. elegans, recently has been used to test the virulence of Salmonella and it is easy to maintain and work with in the laboratory. The results revealed that the morphology obtained by Transmission Electron Microscopy of two phages from the PHA46 cocktail correspond to a myovirus, the analyses of their genomes sequences did not report virulence or antimicrobial resistance genes. The PHA46 sample is specific for 33 different serovars from different Salmonella strains and shows stability at 7 °C and pH 6. Also, the PHA46 cocktail was effective in reducing the adherence of S. Newport-45 and S. Typhimurium SL1344 to cherry tomatoes, at an average of 0.9 log10, respectively. Regarding internalized bacteria, the reduction was at an average of 1.2 log10, of the serovars mentioned above. The lifespan experiments in C. elegans showed by itself, that the PHA46 cocktail was harmless to the nematode, and the virulence from both Salmonella strains grown in vitro is diminished in the presence of the PHA46 cocktail. In conclusion, these results showed that the PHA46 cocktail could be a good candidate to be used as a biocontrol agent against Salmonella enterica.
Assuntos
Caenorhabditis elegans , Fagos de Salmonella , Salmonella typhimurium , Solanum lycopersicum , Solanum lycopersicum/microbiologia , Animais , Caenorhabditis elegans/microbiologia , Salmonella typhimurium/virologia , Fagos de Salmonella/genética , Fagos de Salmonella/fisiologia , Virulência , Salmonella enterica/virologia , Microbiologia de Alimentos , Agentes de Controle Biológico , Especificidade de HospedeiroRESUMO
Enterobacter cloacae is a clinically significant pathogen due to its multi-resistance to antibiotics, presenting a challenge in the treatment of infections. As concerns over antibiotic resistance escalate, novel therapeutic approaches have been explored. Bacteriophages, characterized by their remarkable specificity and ability to self-replicate within target bacteria, are emerging as a promising alternative therapy. In this study, we isolated and partially characterized nine lytic bacteriophages targeting E. cloacae, with two selected for comprehensive genomic analysis based on their host range and bacteriolytic activity. All identified phages exhibited a narrow host range, demonstrated stability within a temperature range of 30-60 °C, displayed pH tolerance from 3 to 10, and showed an excellent bacteriolytic capacity for up to 18 h. Notably, the fully characterized phage genomes revealed an absence of lysogenic, virulence, or antibiotic-resistance genes, positioning them as promising candidates for therapeutic intervention against E. cloacae-related diseases. Nonetheless, translating this knowledge into practical therapeutic applications mandates a deeper understanding of bacteriophage interactions within complex biological environments.
Assuntos
Bacteriófagos , Enterobacter cloacae , Genoma Viral , Genômica , Especificidade de Hospedeiro , Enterobacter cloacae/virologia , Enterobacter cloacae/genética , Bacteriófagos/genética , Bacteriófagos/fisiologia , Bacteriófagos/classificação , Bacteriófagos/isolamento & purificação , Terapia por Fagos , Infecções por Enterobacteriaceae/microbiologia , BacterióliseRESUMO
We searched for common patterns in parasite ecology by investigating species and host contributions to the beta-diversity of infracommunities (=assemblages of parasites harboured by a host individual) in helminths of three species of South African ungulates and fleas of 11 species of South American rodents, assuming that a comparison of patterns in distinctly different parasites and hosts would allow us to judge the generality or, at least, commonness of these patterns. We used data on species' composition and numbers of parasites and asked whether (i) parasite species' attributes (life cycle, transmission mode, and host specificity in helminths; possession of sclerotized combs, microhabitat preference, and host specificity in fleas) or their population structure (mean abundance and/or prevalence) and (ii) host characteristics (sex and age) affect parasite and host species' contributions to parasite beta-diversity (SCBD and HCBD, respectively). We found that parasite species' morphological and ecological attributes were mostly not associated with their SCBD. In contrast, parasite SCBD, in both ungulates and rodents, significantly increased with either parasite mean abundance or prevalence or both. The effect of host characteristics on HCBD was detected in a few hosts only. In general, parasite infracommunities' beta-diversity appeared to be driven by variation in parasite species rather than the uniqueness of the assemblages harboured by individual hosts. We conclude that some ecological patterns (such as the relationships between SCBD and parasite abundance/prevalence) appear to be common and do not differ between different host-parasite associations in different geographic regions, whereas other patterns (the relationships between SCBD and parasite species' attributes) are contingent and depend on parasite and host identities.
Assuntos
Helmintíase Animal , Helmintos , Roedores , Sifonápteros , Animais , Sifonápteros/fisiologia , Sifonápteros/classificação , Helmintíase Animal/parasitologia , Helmintíase Animal/epidemiologia , Helmintos/classificação , Helmintos/fisiologia , Helmintos/isolamento & purificação , Roedores/parasitologia , África do Sul , Masculino , Feminino , Biodiversidade , Interações Hospedeiro-Parasita , Doenças dos Roedores/parasitologia , Doenças dos Roedores/epidemiologia , América do Sul , Especificidade de Hospedeiro , Infestações por Pulgas/parasitologia , Infestações por Pulgas/veterinária , Infestações por Pulgas/epidemiologia , PrevalênciaRESUMO
Genetic variability in phytopathogens is one of the main problems encountered for effective plant disease control. This fact may be related to the presence of transposable elements (TEs), but little is known about their role in host genomes. Here, we performed the most comprehensive analysis of insertion sequences (ISs) and transposons (Tns) in the genomes of the most important bacterial plant pathogens. A total of 35 692 ISs and 71 transposons were identified in 270 complete genomes. The level of pathogen-host specialization was found to be a significant determinant of the element distribution among the species. Some Tns were identified as carrying virulence factors, such as genes encoding effector proteins of the type III secretion system and resistance genes for the antimicrobial streptomycin. Evidence for IS-mediated ectopic recombination was identified in Xanthomonas genomes. Moreover, we found that IS elements tend to be inserted in regions near virulence and fitness genes, such ISs disrupting avirulence genes in X. oryzae genomes. In addition, transcriptome analysis under different stress conditions revealed differences in the expression of genes encoding transposases in the Ralstonia solanacearum, X. oryzae, and P. syringae species. Lastly, we also investigated the role of Tns in regulation via small noncoding regulatory RNAs and found these elements may target plant-cell transcriptional activators. Taken together, the results indicate that TEs may have a fundamental role in variability and virulence in plant pathogenic bacteria.
Assuntos
Elementos de DNA Transponíveis , Pequeno RNA não Traduzido , Elementos de DNA Transponíveis/genética , Bactérias , Perfilação da Expressão Gênica , Especificidade de Hospedeiro , Doenças das PlantasRESUMO
Over recent years, fish parasites of the genus Cymothoa Fabricius, 1793, have received increased attention due to both their ecological and their economic importance to aquaculture and fishery. As the studies about Cymothoa have increased this improve our understanding on the host specificity and distribution of these parasites. The aim of this paper was to review the current global geographic distribution, distribution patterns and parasite-host interactions patterns of Cymothoa spp. associated with fish from marine and brackish water bodies around the world. A total of 144 samples were analyzed, from which 23 species of Cymothoa were found parasitizing 84 teleost fish species of 35 families and 20 orders. Most of these parasites were found in the mouth of the host fish, including in wild fish. The highest occurrence of parasites was found in host species belonging to the families Carangidae and Lutjanidae. Host specificity was an important factor in the geographic distribution of Cymothoa species as also environmental temperature. Cymothoa indica, Cymothoa exigua and Cymothoa excisa were the species with lowest specificity for host family and widest geographic distribution.
Assuntos
Doenças dos Peixes , Peixes , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Isópodes , Animais , Isópodes/classificação , Isópodes/parasitologia , Peixes/parasitologia , Peixes/classificação , Doenças dos Peixes/parasitologia , Distribuição AnimalRESUMO
The correct identification of variables affecting parasite diversity and assemblage composition at different spatial scales is crucial for understanding how pathogen distribution responds to anthropogenic disturbance and climate change. Here, we used a database of avian haemosporidian parasites to test how the taxonomic and phylogenetic diversity and phylogenetic structure of the genera Plasmodium, Haemoproteus and Leucocytozoon from three zoogeographic regions are related to surrogate variables of Earth's energy input, habitat heterogeneity (climatic diversity, landscape heterogeneity, host richness and human disturbance) and ecological interactions (resource use), which was measured by a novel assemblage-level metric related to parasite niche overlap (degree of generalism). We found that different components of energy input explained variation in richness for each genus. We found that human disturbance influences the phylogenetic structure of Haemoproteus while the degree of generalism explained richness and phylogenetic structure of Plasmodium and Leucocytozoon genera. Furthermore, landscape attributes related to human disturbance (human footprint) can filter Haemoproteus assemblages by their phylogenetic relatedness. Finally, assembly processes related to resource use within parasite assemblages modify species richness and phylogenetic structure of Plasmodium and Leucocytozoon assemblages. Overall, our study highlighted the genus-specific patterns with the different components of Earth's energy budget, human disturbances and degree of generalism.
Assuntos
Haemosporida , Especificidade de Hospedeiro , Humanos , Animais , Filogenia , Efeitos Antropogênicos , AvesRESUMO
Host phylogeny and ecological convergence are two factors thought to influence the structure of parasite communities. The aims of this study were to determine the diversity of metazoan parasites of 10 sympatric fish species of the family Carangidae from the southeastern Gulf of California, and to analyze their similarity at infracommunity and component community levels, in order to determine if the host species, particularly those congeneric with similar ecological characteristics, exhibit similar assemblages of parasites. In total, 874 fish specimens were examined and 40 parasite species were identified. The component community was composed by 21 parasite species in Caranx caninus, 20 in C. caballus, 11 in C. vinctus, five in Chloroscombrus orqueta, four in Carangoides otrynter, seven in Hemicaranx leucurus, eight in Selene brevoortii, 14 in S. peruviana, and 11 in Trachinotus rhodopus. The metazoan parasite communities of C. vinctus, Ch. orqueta, H. leucurus, and S. brevoortii are reported here for the first time. The parasite communities of the remaining six carangid species have been reported from regions other than the Gulf of California. All fish species differed significantly regarding the diversity of their parasite infracommunities. This possibly is due to different patterns of habitat use among fish species, and because of the differential host specificity among parasite taxa. Nonetheless, when the analysis was restricted to common parasite species, some fish showed similar parasite infracommunities, particularly congeners of the genus Selene as well as C. caballus and C. vinctus. The component communities of species of Selene were highly similar (>65%), but the three species of Caranx were not. This result supports the hypothesis that congeneric fish species with similar ecological filters harbor similar parasite communities. However, the difference observed between C. caninus and C. caballus suggests that these species, despite being evolutionary and ecologically related, have different physiological or immunological characteristics (compatibility filters) that may result in different parasite communities.