RESUMO

Bacteriophages, viruses that infect bacterial hosts, are known to rule the dynamics and diversity of bacterial populations in a number of ecosystems. Bacterial communities residing in the gut of animals, known as the gut microbiome, have revolutionized our understanding of many diseases. However, the gut phageome, while of apparent importance in this context, remains an underexplored area of research. Here we identify for the first time genomic sequences from tailed viruses (Caudoviricetes) that are associated with the microbiome of stingless bees (Melipona quadrifasciata). Both DNA and RNA were extracted from virus particles isolated from healthy and diseased forager bees, the latter showing symptoms from an annual syndrome that only affects M. quadrifasciata. Viral contigs from previously sequenced metagenomes of healthy and diseased forager bees were used for the analyses. Using conserved proteins deduced from their genomes, we found that Caudoviricetes were only present in the worker bee gut microbiome from diseased stingless bees. The most abundant phages are phylogenetically related to phages that infect Gram-positive bacteria from the order Lactobacillales and Gram-negative bacteria from the genus Gilliamella and Bartonella, that are common honey bee symbionts. The potential implication of these viruses in the M. quadrifasciata syndrome is discussed.

RESUMO

Compared to honeybees and bumblebees, the effect of diet on the gut microbiome of Neotropical corbiculate bees such as Melipona spp. is largely unknown. These bees have been managed for centuries, but recently an annual disease is affecting M. quadrifasciata, an endangered species kept exclusively by management in Southern Brazil. Here we report the results of a longitudinal metabarcoding study involving the period of M. quadrifasciata colony weakness, designed to monitor the gut microbiota and diet changes preceding an outbreak. We found increasing amounts of bacteria associated to the gut of forager bees 2 months before the first symptoms have been recorded. Simultaneously, forager bees showed decreasing body weight. The accelerated growth of gut-associated bacteria was uneven among taxa, with Bifidobacteriaceae dominating, and Lactobacillaceae decreasing in relative abundance within the bacterial community. Dominant fungi such as Candida and Starmerella also decreased in numbers, and the stingless bee obligate symbiont Zygosaccharomyces showed the lowest relative abundance during the outbreak period. Such changes were associated with pronounced diet shifts, i.e., the rise of Eucalyptus spp. pollen amount in forager bees' guts. Furthermore, there was a negative correlation between the amount of Eucalyptus pollen in diets and the abundance of some bacterial taxa in the gut-associated microbiota. We conclude that diet and subsequent interactions with the gut microbiome are key environmental components of the annual disease and propose the use of diet supplementation as means to sustain the activity of stingless bee keeping as well as native bee pollination services.

Assuntos

RESUMO

Meliponiculture - the management of stingless bee colonies - is an expanding activity in Brazil with economic, social and environmental potential. However, unlike in apiculture, the pathogens that impact on meliponiculture remain largely unknown. In southern Brazil, every year at the end of the summer, managed colonies of the stingless bee Melipona quadrifasciata manifest a syndrome that eventually leads to collapse. Here we characterize the M. quadrifasciata virome using high-throughput sequencing, with the aim of identifying potentially pathogenic viruses, and test whether they are related to the syndrome outbreaks. Two paired viromes are explored, one from healthy bees and another from unhealthy ones. Each virome is built from metagenomes assembled from sequencing reads derived either from RNA or DNA. A total of 40 621 reads map to viral contigs of the unhealthy bees' metagenomes, whereas only 11 reads map to contigs identified as viruses of healthy bees. The viruses showing the largest copy numbers in the virome of unhealthy bees belong to the family Dicistroviridae - common pathogenic honeybee viruses - as well as Parvoviridae and Circoviridae, which have never been reported as being pathogenic in insects. Our analyses indicate that they represent seven novel viruses associated with stingless bees. PCR-based detection of these viruses in individual bees (healthy or unhealthy) from three different localities revealed a statistically significant association between viral infection and symptom manifestation in one meliponary. We conclude that although viral infections may contribute to colony collapses in the annual syndrome in some meliponaries, viruses spread opportunistically during the outbreak, perhaps due to colony weakness.

Assuntos

RESUMO

Symbioses are ubiquitous and have played an influential role in the evolution of life on Earth. Genomic studies are now revealing a huge diversity of associations among hosts and their microbiotas, allowing us to characterize their complex ecological and evolutionary dynamics. The different transmission modes and the asynchronous cell proliferation of the numerous symbionts associated with one host generate a genomic conflict ought to be solved. Two disputing views have been used to model and predict the outcome of such conflicts. The traditional view is based on community ecology, and considers that selection at the level of individuals is sufficient to explain longstanding associations among species. A new perspective considers that the host and its associated microbiota constitute a biological entity called holobiont, and that regarding it as a higher-level unit of selection is unavoidable to understand phenotypic evolution. Novel extended phenotypes are often built through symbiotic interactions, allowing the holobiont to explore and survive in distinct environmental conditions, and may evolve in a Lamarckian fashion.

RESUMO

Abstract Symbioses are ubiquitous and have played an influential role in the evolution of life on Earth. Genomic studies are now revealing a huge diversity of associations among hosts and their microbiotas, allowing us to characterize their complex ecological and evolutionary dynamics. The different transmission modes and the asynchronous cell proliferation of the numerous symbionts associated with one host generate a genomic conflict ought to be solved. Two disputing views have been used to model and predict the outcome of such conflicts. The traditional view is based on community ecology, and considers that selection at the level of individuals is sufficient to explain longstanding associations among species. A new perspective considers that the host and its associated microbiota constitute a biological entity called holobiont, and that regarding it as a higher-level unit of selection is unavoidable to understand phenotypic evolution. Novel extended phenotypes are often built through symbiotic interactions, allowing the holobiont to explore and survive in distinct environmental conditions, and may evolve in a Lamarckian fashion.

RESUMO

Melipona quadrifasciata is an eusocial stingless bee traditionally used for honey production in Brazil. In the last decades, the species disappeared from the wild in Southern Brazil, being kept exclusively in managed colonies for commercial and recreational purposes. Stingless beekeepers from this region report annual losses of their colonies due to a syndrome of yet unknown causes. We investigate whether it is associated to pathogenic microorganisms already known to cause disease in bees. These results provide a starting point for future studies aimed at clarifying the relationship between the microbial community of stingless bees and their colony collapses.

Assuntos

RESUMO

Echinococcus granulosus is a taeniid cestode and the etiological agent of an infectious zoonotic disease known as cystic echinococcosis (CE) or hydatid disease. CE is a serious public health concern in many parts of the world, including the Americas, where it is highly endemic in many regions. Echinococcus granulosus displays high intraspecific genetic variability and is divided into multiple genotypes (G1-G8, G10) with differences in their biology and etiology. Of these, genotype G1 is responsible for the majority of human and livestock infections and has the broadest host spectrum. However, despite the high significance to the public and livestock health, the data on genetic variability and regional genetic differences of genotype G1 in America are scarce. The aim of this study was to evaluate the genetic variability and phylogeography of G1 in several countries in America by sequencing a large portion of the mitochondrial genome. We analysed 8279bp of mtDNA for 52 E. granulosus G1 samples from sheep, cattle and pigs collected in Argentina, Brazil, Chile and Mexico, covering majority of countries in the Americas where G1 has been reported. The phylogenetic network revealed 29 haplotypes and a high haplotype diversity (Hd=0.903). The absence of phylogeographic segregation between different regions in America suggests the importance of animal transportation in shaping the genetic structure of E. granulosus G1. In addition, our study revealed many highly divergent haplotypes, indicating a long and complex evolutionary history of E. granulosus G1 in the Americas.

Assuntos

RESUMO

This study aimed to identify the parasitical etiologic agents of visceral cysts in pigs from the central/northern region of Rio Grande do Sul State, Brazil. Fifty-eight cysts were found in livers during veterinary inspection of swine slaughtered from January 2008 to 2012. Collected samples were submitted to macroscopic and molecular analyzes. Polymerase chain reaction (PCR), DNA sequencing and BLAST alignment of sequences was used to molecular characterization of the samples. By PCR 10.3% (6/58) of tested samples were positive for Echinococcus granulosus sensu lato and 56.9% (33/58) for Cysticercus tenuicollis. In this study, it was verified the occurrence of larval forms of E. granulosus sensu lato and Taenia hydatigena in pig herds from the central/northern region of Rio Grande do Sul State. The presence of both parasites is relevant due to the economic losses for the meat industry. Additionally, E. granulosus sensu lato has zoonotic importance and may be infecting pig herds in southern Brazil.

Assuntos

RESUMO

This study aimed to identify the parasitical etiologic agents of visceral cysts in pigs from the central/northern region of Rio Grande do Sul State, Brazil. Fifty-eight cysts were found in livers during veterinary inspection of swine slaughtered from January 2008 to 2012. Collected samples were submitted to macroscopic and molecular analyzes. Polymerase chain reaction (PCR), DNA sequencing and BLAST alignment of sequences was used to molecular characterization of the samples. By PCR 10.3% (6/58) of tested samples were positive for Echinococcus granulosus sensu lato and 56.9% (33/58) for Cysticercus tenuicollis. In this study, it was verified the occurrence of larval forms of E. granulosus sensu lato and Taenia hydatigena in pig herds from the central/northern region of Rio Grande do Sul State. The presence of both parasites is relevant due to the economic losses for the meat industry. Additionally, E. granulosus sensu lato has zoonotic importance and may be infecting pig herds in southern Brazil.(AU)

Neste estudo, buscou-se identificar os agentes etiológicos de origem parasitária em cistos nas vísceras de suínos oriundos sa região centro/norte do sEstado do Rio Grande do Sul, Brasil. Cinquenta e oito cistos foram encontrados durante a inspeção veterinária em fígados de suínos abatidos entre janeiro de 2008 a 2012. As amostras foram submetidas às análises macroscópicas e moleculares. Reação em cadeia da polimerase (PCR), sequenciamento de DNA e alinhamento das sequências no BLAST (bases de dados do GenBank) foram utilizados na caracterização molecular das amostras. Das amostras analisadas, 10,3% (6/58) foram positivas para Echinococcus granulosus sensu lato e 56,9% (33/58) para Cysticercus tenuicollis. Evidenciou-se a ocorrência de larvas de E. granulosus sensu lato e Taenia hydatigena em rebanhos suínos na região centro/norte do RS. A presença de ambos os agentes é relevante devido às perdas econômicas para a indústria de carnes. Além disso, destaca-se que E. granulosus sensu lato possui importância zoonótica e pode contaminar os rebanhos suínos no sul do Brasil.(AU)

Assuntos

RESUMO

This study aimed to identify the parasitical etiologic agents of visceral cysts in pigs from the central/northern region of Rio Grande do Sul State, Brazil. Fifty-eight cysts were found in livers during veterinary inspection of swine slaughtered from January 2008 to 2012. Collected samples were submitted to macroscopic and molecular analyzes. Polymerase chain reaction (PCR), DNA sequencing and BLAST alignment of sequences was used to molecular characterization of the samples. By PCR 10.3% (6/58) of tested samples were positive for Echinococcus granulosus sensu lato and 56.9% (33/58) for Cysticercus tenuicollis. In this study, it was verified the occurrence of larval forms of E. granulosus sensu lato and Taenia hydatigena in pig herds from the central/northern region of Rio Grande do Sul State. The presence of both parasites is relevant due to the economic losses for the meat industry. Additionally, E. granulosus sensu lato has zoonotic importance and may be infecting pig herds in southern Brazil.

Neste estudo, buscou-se identificar os agentes etiológicos de origem parasitária em cistos nas vísceras de suínos oriundos sa região centro/norte do sEstado do Rio Grande do Sul, Brasil. Cinquenta e oito cistos foram encontrados durante a inspeção veterinária em fígados de suínos abatidos entre janeiro de 2008 a 2012. As amostras foram submetidas às análises macroscópicas e moleculares. Reação em cadeia da polimerase (PCR), sequenciamento de DNA e alinhamento das sequências no BLAST (bases de dados do GenBank) foram utilizados na caracterização molecular das amostras. Das amostras analisadas, 10,3% (6/58) foram positivas para Echinococcus granulosus sensu lato e 56,9% (33/58) para Cysticercus tenuicollis. Evidenciou-se a ocorrência de larvas de E. granulosus sensu lato e Taenia hydatigena em rebanhos suínos na região centro/norte do RS. A presença de ambos os agentes é relevante devido às perdas econômicas para a indústria de carnes. Além disso, destaca-se que E. granulosus sensu lato possui importância zoonótica e pode contaminar os rebanhos suínos no sul do Brasil.

Assuntos