Arsenophonus
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Symbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated with Melophagus ovinus, a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites. Interestingly, the whole system provides a remarkable analogy to the association between Glossina and its symbiotic bacteria. In both, the symbiotic systems are composed of an obligate symbiont and two facultative intracellular associates, Sodalis and Wolbachia. In addition, extracellular Bartonella resides in the gut of Melophagus. However, the phylogenetic origins of the two obligate mutualist symbionts differ. In Glossina, the mutualistic Wigglesworthia appears to be a relatively isolated symbiotic lineage, whereas in Melophagus, the obligate symbiont originated within the widely distributed Arsenophonus cluster. Although phylogenetically distant, the two obligate symbionts display several remarkably similar traits (e.g., transmission via the host's "milk glands" or similar pattern of genome reduction). To obtain better insight into the biology and possible role of the M. ovinus obligate symbiont, "Candidatus Arsenophonus melophagi," we performed several comparisons of its gene content based on assignments of the Cluster of Orthologous Genes (COG). Using this criterion, we show that within a set of 44 primary and secondary symbionts, "Ca. Arsenophonus melophagi" is most similar to Wigglesworthia. On the other hand, these two bacteria also display interesting differences, such as absence of flagellar genes in Arsenophonus and their presence in Wigglesworthia. This finding implies that a flagellum is not essential for bacterial transmission via milk glands.
- MeSH
- DNA bakterií chemie genetika MeSH
- Enterobacteriaceae klasifikace genetika izolace a purifikace fyziologie MeSH
- fylogeneze MeSH
- genom bakteriální MeSH
- mikroskopie MeSH
- molekulární sekvence - údaje MeSH
- moucha tse-tse mikrobiologie fyziologie MeSH
- Phthiraptera mikrobiologie fyziologie MeSH
- sekvenční analýza DNA MeSH
- sekvenční homologie MeSH
- shluková analýza MeSH
- symbióza * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
The genes of ribosomal RNA are the most popular and frequently used markers for bacterial phylogeny and reconstruction of insect-symbiont coevolution. In primary symbionts, such as Buchnera and Wigglesworthia, genome economization leads to the establishment of a single copy of these sequences. In phylogenetic studies, they provide sufficient information and yield phylogenetic trees congruent with host evolution. In contrast, other symbiotic lineages (e.g., the genus Arsenophonus) carry a higher number of rRNA copies in their genomes, which may have serious consequences for phylogenetic inference. In this study, we show that in Arsenophonus triatominarum the degree of heterogeneity can affect reconstruction of phylogenetic relationships and mask possible coevolution between the symbiont and its host. Phylogenetic arrangement of individual rRNA copies was used, together with a calculation of their divergence time, to demonstrate that the incongruent 16S rDNA trees and low nucleotide diversity in the secondary symbiont could be reconciled with the coevolutionary scenario.
- MeSH
- DNA bakterií genetika chemie MeSH
- Enterobacteriaceae genetika izolace a purifikace klasifikace MeSH
- financování organizované MeSH
- fylogeneze MeSH
- mezerníky ribozomální DNA genetika chemie MeSH
- molekulární evoluce MeSH
- molekulární sekvence - údaje MeSH
- polymorfismus genetický MeSH
- RNA ribozomální 16S genetika MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- sekvenční seřazení MeSH
- Triatoma mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
AIMS: The winter beehive debris containing bodies of honeybee parasitic mite Varroa destructor is used for veterinary diagnostics. The Varroa sucking honeybee haemolymph serves as a reservoir of pathogens including bacteria. Worker bees can pick up pathogens from the debris during cleaning activities and spread the infection to healthy bees within the colony. The aim of this study was to detect entomopathogenic bacteria in the Varroa collected from the winter beehive debris. METHODS AND RESULTS: Culture-independent approach was used to analyse the mite-associated bacterial community. Total DNA was extracted from the samples of 10 Varroa female individuals sampled from 27 different sites in Czechia. The 16S rRNA gene was amplified using universal bacterial primers, cloned and sequenced, resulting in a set of 596 sequences representing 29 operational taxonomic units (OTU97). To confirm the presence of bacteria in Varroa, histological sections of the mites were observed. Undetermined bacteria were observed in the mite gut and fat tissue. CONCLUSION: Morganella sp. was the most frequently detected taxon, followed by Enterococcus sp., Pseudomonas sp., Rahnella sp., Erwinia sp., and Arsenophonus sp. The honeybee putative pathogen Spiroplasma sp. was detected at one site and Bartonella-like bacteria were found at four sites. PCR-based analysis using genus-specific primers enabled detection of the following taxa: Enterococcus, Bartonella-like bacteria, Arsenophonus and Spiroplasma. SIGNIFICANCE AND IMPACT OF THE STUDY: We found potentially pathogenic (Spiroplasma) and parasitic bacteria (Arsenophonus) in mites from winter beehive debris. The mites can be reservoirs of the pathogenic bacteria in the apicultures.
- MeSH
- Bacteria klasifikace genetika izolace a purifikace MeSH
- fylogeneze MeSH
- molekulární sekvence - údaje MeSH
- RNA ribozomální 16S genetika MeSH
- roční období MeSH
- Varroidae mikrobiologie fyziologie MeSH
- včely růst a vývoj parazitologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The symbiotic microorganisms of arthropod vectors are highly significant from several points of view, partly due to their possible roles in the transmission of pathogenic causative agents by blood-sucking vectors. Although ticks are well studied because of their significance to human health, novel microbial associations remain to be described. This review summarises several endosymbiotic bacterial species in hard ticks from various parts of the world, including Coxiella-, Francisella-, Rickettsia- and Arsenophonus-like symbionts as well as Candidatus Midichloria mitochondrii and Wolbachia. New methodologies for the isolation and characterization of tick-associated bacteria will, in turn, encourage new strategies of tick control by studying their endosymbionts.
Insect microbiomes influence many fundamental host traits, including functions of practical significance such as their capacity as vectors to transmit parasites and pathogens. The knowledge on the diversity and development of the gut microbiomes in various blood feeding insects is thus crucial not only for theoretical purposes, but also for the development of better disease control strategies. In Triatominae (Heteroptera: Reduviidae), the blood feeding vectors of Chagas disease in South America and parts of North America, the investigation of the microbiomes is in its infancy. The few studies done on microbiomes of South American Triatominae species indicate a relatively low taxonomic diversity and a high host specificity. We designed a comparative survey to serve several purposes: (I) to obtain a better insight into the overall microbiome diversity in different species, (II) to check the long term stability of the interspecific differences, (III) to describe the ontogenetic changes of the microbiome, and (IV) to determine the potential correlation between microbiome composition and presence of Trypanosoma cruzi, the causative agent of Chagas disease. Using 16S amplicons of two abundant species from the southern US, and four laboratory reared colonies, we showed that the microbiome composition is determined by host species, rather than locality or environment. The OTUs (Operational Taxonomic Units) determination confirms a low microbiome diversity, with 12-17 main OTUs detected in wild populations of T. sanguisuga and T. protracta. Among the dominant bacterial taxa are Acinetobacter and Proteiniphilum but also the symbiotic bacterium Arsenophonus triatominarum, previously believed to only live intracellularly. The possibility of ontogenetic microbiome changes was evaluated in all six developmental stages and feces of the laboratory reared model Rhodnius prolixus. We detected considerable changes along the host's ontogeny, including clear trends in the abundance variation of the three dominant bacteria, namely Enterococcus, Acinetobacter, and Arsenophonus. Finally, we screened the samples for the presence of Trypanosoma cruzi. Comparing the parasite presence with the microbiome composition, we assessed the possible significance of the latter in the epidemiology of the disease. Particularly, we found a trend toward more diverse microbiomes in Trypanosoma cruzi positive T. protracta specimens.
- Publikační typ
- časopisecké články MeSH
Ticks are important vectors of various pathogens that cause infectious diseases in humans. Endosymbiotic bacteria have been explored as targets for tick and tick-borne disease control. However, the tick bacterial community on Hainan Island, which is the largest tropical island in China and has an environment favourable to ticks, has not yet been studied. In this study, we surveyed the bacterial community of ticks collected from grass in one village in Haikou. A total of 20 ticks were morphologically and molecularly identified as Haemaphysalis spp. The tick bacterial 16S rRNA hypervariable region amplicon libraries were sequenced on an Illumina MiSeq platform. A total of 10 possible bacterial genera were detected, indicating a low-diversity bacterial community profile. The dominant bacterial genus, Massilia, accounted for 97.85% of the population. Some other bacterial genera, including Arsenophonus and Pseudomonas, have been reported to play a role in tick development and tick-borne pathogen transmission in other tick species. Overall, the study highlights the first descriptive understanding of the tick bacterial community on Hainan Island and provides a basis for deciphering the interactions between the tick microbiome and tick-borne pathogens.
- MeSH
- Bacteria genetika MeSH
- Ixodidae * mikrobiologie MeSH
- klíšťata * MeSH
- lidé MeSH
- RNA ribozomální 16S genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Čína MeSH
The ectoparasitic mite Varroa destructor is a major pest of the honeybee Apis mellifera. In a previous study, bacteria were found in the guts of mites collected from winter beehive debris and were identified using Sanger sequencing of their 16S rRNA genes. In this study, community comparison and diversity analyses were performed to examine the microbiota of honeybees and mites at the population level. The microbiota of the mites and honeybees in 26 colonies in seven apiaries in Czechia was studied. Between 10 and 50 Varroa females were collected from the bottom board, and 10 worker bees were removed from the peripheral comb of the same beehive. Both bees and mites were surface sterilized. Analysis of the 16S rRNA gene libraries revealed significant differences in the Varroa and honeybee microbiota. The Varroa microbiota was less diverse than was the honeybee microbiota, and the relative abundances of bacterial taxa in the mite and bee microbiota differed. The Varroa mites, but not the honeybees, were found to be inhabited by Diplorickettsia. The relative abundance of Arsenophonus, Morganella, Spiroplasma, Enterococcus, and Pseudomonas was higher in Varroa than in honeybees, and the Diplorickettsia symbiont detected in this study is specific to Varroa mites. The results demonstrated that there are shared bacteria between Varroa and honeybee populations but that these bacteria occur in different relative proportions in the honeybee and mite bacteriomes. These results support the suggestion of bacterial transfer via mites, although only some of the transferred bacteria may be harmful.
- MeSH
- biodiverzita MeSH
- DNA bakterií genetika MeSH
- mikrobiota * MeSH
- RNA ribozomální 16S genetika MeSH
- roční období MeSH
- sekvenční analýza DNA MeSH
- Spiroplasma klasifikace izolace a purifikace MeSH
- symbióza MeSH
- Varroidae mikrobiologie MeSH
- včely mikrobiologie parazitologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region) we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.
- MeSH
- DNA bakterií genetika MeSH
- Enterobacteriaceae genetika metabolismus fyziologie MeSH
- fylogeneze * MeSH
- molekulární evoluce MeSH
- moucha tse-tse mikrobiologie MeSH
- ribozomální DNA genetika MeSH
- sekvenční analýza DNA MeSH
- symbióza * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The bacterial family Enterobacteriaceae gave rise to a variety of symbiotic forms, from the loosely associated commensals, often designated as secondary (S) symbionts, to obligate mutualists, called primary (P) symbionts. Determination of the evolutionary processes behind this phenomenon has long been hampered by the unreliability of phylogenetic reconstructions within this group of bacteria. The main reasons have been the absence of sufficient data, the highly derived nature of the symbiont genomes and lack of appropriate phylogenetic methods. Due to the extremely aberrant nature of their DNA, the symbiotic lineages within Enterobacteriaceae form long branches and tend to cluster as a monophyletic group. This state of phylogenetic uncertainty is now improving with an increasing number of complete bacterial genomes and development of new methods. In this study, we address the monophyly versus polyphyly of enterobacterial symbionts by exploring a multigene matrix within a complex phylogenetic framework. RESULTS: We assembled the richest taxon sampling of Enterobacteriaceae to date (50 taxa, 69 orthologous genes with no missing data) and analyzed both nucleic and amino acid data sets using several probabilistic methods. We particularly focused on the long-branch attraction-reducing methods, such as a nucleotide and amino acid data recoding and exclusion (including our new approach and slow-fast analysis), taxa exclusion and usage of complex evolutionary models, such as nonhomogeneous model and models accounting for site-specific features of protein evolution (CAT and CAT+GTR). Our data strongly suggest independent origins of four symbiotic clusters; the first is formed by Hamiltonella and Regiella (S-symbionts) placed as a sister clade to Yersinia, the second comprises Arsenophonus and Riesia (S- and P-symbionts) as a sister clade to Proteus, the third Sodalis, Baumannia, Blochmannia and Wigglesworthia (S- and P-symbionts) as a sister or paraphyletic clade to the Pectobacterium and Dickeya clade and, finally, Buchnera species and Ishikawaella (P-symbionts) clustering with the Erwinia and Pantoea clade. CONCLUSIONS: The results of this study confirm the efficiency of several artifact-reducing methods and strongly point towards the polyphyly of P-symbionts within Enterobacteriaceae. Interestingly, the model species of symbiotic bacteria research, Buchnera and Wigglesworthia, originated from closely related, but different, ancestors. The possible origins of intracellular symbiotic bacteria from gut-associated or pathogenic bacteria are suggested, as well as the role of facultative secondary symbionts as a source of bacteria that can gradually become obligate maternally transferred symbionts.
- MeSH
- Bayesova věta MeSH
- Buchnera genetika fyziologie MeSH
- DNA bakterií genetika MeSH
- Enterobacteriaceae genetika fyziologie MeSH
- fylogeneze MeSH
- genom bakteriální MeSH
- molekulární evoluce MeSH
- symbióza MeSH
- Wigglesworthia genetika fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
