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.
The pea aphid genome was recently found to harbor genes for carotenoid biosynthesis, reflecting an ancestral transfer from a fungus. To explore the evolution of the carotene desaturase gene family ...within aphids, sequences were retrieved from a set of 34 aphid species representing numerous deeply diverging lineages of aphids and analyzed together with fungal sequences retrieved from databases. All aphids have at least one copy of this gene and some aphid species have up to seven, whereas fungal genomes consistently have a single copy. The closest relatives of aphids, adelgids, also have carotene desaturase; these sequences are most closely related to those from aphids, supporting a shared origin from a fungal to insect transfer predating the divergence of adelgids and aphids. Likewise, all aphids, and adelgids, have carotenoid profiles that are consistent with their biosynthesis using the acquired genes of fungal origin rather than derivation from food plants. The carotene desaturase was acquired from a fungal species outside of Ascomycota or Basidiomycota and closest to Mucoromycotina among sequences available in databases. In aphids, an ongoing pattern of gene duplication is indicated by the presence of both anciently and recently diverged paralogs within genomes and by the presence of a high frequency of pseudogenes that appear to be recently inactivated. Recombination among paralogs is evident, making analyses of patterns of selection difficult, but tests of selection for a nonrecombining region indicates that duplications tend to be followed by bouts of positive selection. Species of Macrosiphini, which often show color polymorphisms, typically have a larger number of desaturase copies relative to other species sampled in the study. These results indicate that aphid evolution has been accompanied by ongoing evolution of carotenogenic genes, which have undergone duplication, recombination, and occasional positive selection to yield a wide variety of carotenoid profiles in different aphid species.
Obligate symbiotic bacteria associated with the insects feeding exclusively on vertebrate blood are supposed to complement B vitamins presumably lacking in their diet. Recent genomic analyses ...revealed considerable differences in biosynthetic capacities across different symbionts, suggesting that levels of B vitamins may vary across different vertebrate hosts. However, a rigorous determination of B vitamins content in blood of various vertebrates has not yet been approached. A reliable analytical method focused on B vitamin complex in blood can provide valuable informative background and understanding of general principles of insect symbiosis. In this work, a chromatographic separation of eight B vitamins (thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid, and cyanocobalamine), four B vitamin derivatives (niacinamide, pyridoxal-5-phosphate, 4-pyridoxic acid, and tetrahydrofolic acid), and 3 stable isotope labelled internal standards was developed. Detection was carried out using dual-pressure linear ion trap mass spectrometer in FullScan MS/MS and SIM mode. Except for vitamin B9 (tetrahydrofolic acid), the instrument quantitation limits of all analytes were ranging from 0.42 to 5.0 μg/L, correlation coefficients from 0.9997 to 1.0000, and QC coefficients from 0.53 to 3.2%. Optimization of whole blood sample preparation step was focused especially on evaluation of two types of protein-precipitation agents: trichloroacetic acid and zinc sulphate in methanol. The best results were obtained for zinc sulphate in methanol, but only nine analytes were successfully validated. Accuracy of the procedure using this protein-precipitating agent was ranging from 89 to 120%, precision from 0.5 to 13%, and process efficiency from 65 to 108%. The content of B vitamins in whole blood samples from human and various vertebrates is presented as an application example of this newly developed method.
The genus Arsenophonus is a group of symbiotic, mainly insect-associated bacteria with rapidly increasing number of records. It is known from a broad spectrum of hosts and symbiotic relationships ...varying from parasitic son-killers to coevolving mutualists.The present study extends the currently known diversity with 34 samples retrieved mainly from hippoboscid (Diptera: Hippoboscidae) and nycteribiid (Diptera: Nycteribiidae) hosts, and investigates phylogenetic relationships within the genus.
The analysis of 110 Arsenophonus sequences (incl. Riesia and Phlomobacter), provides a robust monophyletic clade, characterized by unique molecular synapomorphies. On the other hand, unstable inner topology indicates that complete understanding of Arsenophonus evolution cannot be achieved with 16S rDNA. Moreover, taxonomically restricted Sampling matrices prove sensitivity of the phylogenetic signal to sampling; in some cases, Arsenophonus monophyly is disrupted by other symbiotic bacteria. Two contrasting coevolutionary patterns occur throughout the tree: parallel host-symbiont evolution and the haphazard association of the symbionts with distant hosts. A further conspicuous feature of the topology is the occurrence of monophyletic symbiont lineages associated with monophyletic groups of hosts without a co-speciation pattern. We suggest that part of this incongruence could be caused by methodological artifacts, such as intragenomic variability.
The sample of currently available molecular data presents the genus Arsenophonus as one of the richest and most widespread clusters of insect symbiotic bacteria. The analysis of its phylogenetic lineages indicates a complex evolution and apparent ecological versatility with switches between entirely different life styles. Due to these properties, the genus should play an important role in the studies of evolutionary trends in insect intracellular symbionts. However, under the current practice, relying exclusively on 16S rRNA sequences, the phylogenetic analyses are sensitive to various methodological artifacts that may even lead to description of new Arsenophonus lineages as independent genera (e.g. Riesia and Phlomobacter). The resolution of the evolutionary questions encountered within the Arsenophonus clade will thus require identification of new molecular markers suitable for the low-level phylogenetics.
The paper investigates the recent population development of Moravian rural micro-regions. It divides all 72 micro-regions into four categories according to the relation of natural demographic balance ...and net migration in the period of 2012–2016. It showed that all size categories of the Moravian rural municipalities till 5000 inhabitants are gaining population by migration whereas small towns lose inhabitants. No relation between the demographic type of the countryside and unemployment was observed. It shows, that the Moravian rural areas are not depopulating in general, its demographic development does not depend on the unemployment. However, the Moravian countryside is differentiated. There are some extremely peripheral parts of Moravia often lacking any real urban centre, where the depopulation is the problem. Depopulating micro-regions can be found in the northern, south-western and eastern periphery of Moravia. Such territories should be solved individually according to the local conditions.
•The paper investigates the recent population development of 72 rural micro-regions.•Only the most peripheral micro-regions without any town centre are threatened.•Rural unemployment is in no case higher than the indicator in the related town centre.•The Moravian countryside is not depopulating, neither ageing.
Wind energy research is dominated by studies of local acceptance (or not) of wind farms and comparative studies at a national level. Research on the spatial differentiation of wind energy ...developments at the regional level is still insufficient, however. This study provides new empirical evidence for the extent to which regional differences in the deployment of wind energy are related to specific environmental and socioeconomic factors, by a statistical analysis of data for districts in the Czech Republic. Unlike previous studies, we found that the installed capacity of wind energy cannot be well predicted by wind potential, land area and population density in an area. In the Czech Republic, wind farms more likely have been implemented in more urbanised, environmentally deprived coal-mining areas that are affected by economic depression. It seems that in environmentally deprived areas, wind energy is more positively accepted as an alternative source to coal, and the economic motivation (financial benefits for municipalities) can have a greater effect on local acceptance, while public opposition is less efficient due to lower social capital and involvement in political matters. Based on these results, some implications for the planning and spatial targeting of new wind farms are discussed.
The phylogenetic diversity of symbiotic bacteria in sucking lice suggests that lice have a complex history of symbiont acquisition, loss, and replacement throughout their evolution. These processes ...have resulted in the establishment of different, phylogenetically distant bacteria as obligate mutualists in different louse groups. By combining metagenomics and amplicon screening across several populations of three louse species (members of the genera Polyplax and Hoplopleura) we describe a novel louse symbiont lineage related to Neisseria and Snodgrassella, and show its independent origin in the two louse genera. While the genomes of these symbionts are highly similar, their respective distributions and status within lice microbiomes indicate that they have different functions and history. In Hoplopleura acanthopus, the Neisseriaceae‐related bacterium is a dominant obligate symbiont present across several host populations. In contrast, the Polyplax microbiomes are dominated by the obligate symbiont Legionella polyplacis, with the Neisseriaceae‐related bacterium co‐occurring only in some samples and with much lower abundance. The results thus support the view that compared to other exclusively blood feeding insects, Anoplura possess a unique capacity to acquire symbionts from diverse groups of bacteria.
Wolbachia belong to highly abundant bacteria which are frequently found in invertebrate microbiomes and manifest by a broad spectrum of lifestyles from parasitism to mutualism. Wolbachia supergroup F ...is a particularly interesting clade as it gave rise to symbionts of both arthropods and nematodes, and some of its members are obligate mutualists. Investigations on evolutionary transitions among the different symbiotic stages have been hampered by a lack of the known diversity and genomic data for the supergroup F members.
Based on amplicon screening, short- and long-read WGS approaches, and laser confocal microscopy, we characterize five new supergroup F Wolbachia strains from four chewing lice species. These strains reached different evolutionary stages and represent two remarkably different types of symbiont genomes. Three of the genomes resemble other known members of Wolbachia F supergroup, while the other two show typical signs of ongoing gene inactivation and removal (genome size, coding density, low number of pseudogenes). Particularly, wMeur1, a symbiont fixed in microbiomes of Menacanthus eurysternus across four continents, possesses a highly reduced genome of 733,850 bp. The horizontally acquired capacity for pantothenate synthesis and localization in specialized bacteriocytes suggest its obligate nutritional role.
The genome of wMeur1 strain, from the M. eurysternus microbiome, represents the smallest currently known Wolbachia genome and the first example of Wolbachia which has completed genomic streamlining as known from the typical obligate symbionts. This points out that despite the large amount and great diversity of the known Wolbachia strains, evolutionary potential of these bacteria still remains underexplored. The diversity of the four chewing lice microbiomes indicates that this vast parasitic group may provide suitable models for further investigations. Video Abstract.
The geography of ageing is addressed in this article by providing new empirical evidence about the significant role of daily activities on the perceptions of isolation and loneliness. The developed ...model of socio-spatial isolation is based on data from time-space diaries and questionnaires completed by older adults living in three cities in the Czech Republic. The study suggests that socio-spatial isolation is a multicomponent (consisting of passivity, isolation and loneliness components), place-dependent and gendered issue. The passivity is significantly associated with the income and leisure sport activities. The isolation can be well predicted by the age, gender and education, and the frequency of work and specific leisure activities, which are constrained by health conditions, financial opportunities and spatial mobility. Particularly trips to nature, sport activities, cultural events, get together with friends, and visits to restaurants have a positive effect on reducing isolation. Women, particularly those who raised more children, more likely feel lonely in old age when family contacts are reduced. Visits to restaurants, shopping malls and cultural events have a positive effect on reducing loneliness. A constrained mobility and higher time consumption for necessary activities also proved to be an age-related and gendered problem. In this respect, policy interventions should seek to improve flexible work opportunities, the digital skills of older people, and the accessibility and safety of public transport with regard to perceived constraints, which is gaining in importance in the Covid-19 era.
Abstract
Legionellaceae are intracellular bacteria known as important human pathogens. In the environment, they are mainly found in biofilms associated with amoebas. In contrast to the ...gammaproteobacterial family Enterobacteriaceae, which established a broad spectrum of symbioses with many insect taxa, the only instance of legionella-like symbiont has been reported from lice of the genus Polyplax. Here, we sequenced the complete genome of this symbiont and compared its main characteristics to other Legionella species and insect symbionts. Based on rigorous multigene phylogenetic analyses, we confirm this bacterium as a member of the genus Legionella and propose the name Candidatus Legionella polyplacis, sp.n. We show that the genome of Ca. Legionella polyplacis underwent massive degeneration, including considerable size reduction (529.746 bp, 484 protein coding genes) and a severe decrease in GC content (23%). We identify several possible constraints underlying the evolution of this bacterium. On one hand, Ca. Legionella polyplacis and the louse symbionts Riesia and Puchtella experienced convergent evolution, perhaps due to adaptation to similar hosts. On the other hand, some metabolic differences are likely to reflect different phylogenetic positions of the symbionts and hence availability of particular metabolic function in the ancestor. This is exemplified by different arrangements of thiamine metabolism in Ca. Legionella polyplacis and Riesia. Finally, horizontal gene transfer is shown to play a significant role in the adaptive and diversification process. Particularly, we show that Ca. L. polyplacis horizontally acquired a complete biotin operon (bioADCHFB) that likely assisted this bacterium when becoming an obligate mutualist.
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