Publications by authors named "Brune A"

Cellulolytic flagellates are essential for the symbiotic digestion of lignocellulose in the gut of lower termites. Most species are associated with host-specific consortia of bacterial symbionts from various phyla. 16S rRNA-based diversity studies and taxon-specific fluorescence in situ hybridization revealed a termite-specific clade of Actinomycetales that colonise the cytoplasm of Trichonympha spp.

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Article Synopsis
  • The study explores the differences in gut microbiota and fiber digestion between lower termites (LT), which have cellulolytic flagellates, and higher termites (HT), which do not.
  • It identifies specific bacterial lineages responsible for fiber breakdown, revealing that Bacteroidota and Spirochaetota dominate the lignocellulolytic activity in LT, while Fibrobacterota and Spirochaetota take over in HT.
  • The findings highlight the importance of oxygen in the breakdown of cellulose and lignin in termite guts, suggesting a more complex symbiotic relationship than previously understood.
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Recent metagenomic studies have identified numerous lineages of hydrogen-dependent, obligately methyl-reducing methanogens. Yet, only a few representatives have been isolated in pure culture. Here, we describe six new species with this capability in the family Methanosarcinaceae (order Methanosarcinales), which makes up a substantial fraction of the methanogenic community in arthropod guts.

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Bacterial endosymbionts of eukaryotic hosts typically experience massive genome reduction, but the underlying evolutionary processes are often obscured by the lack of free-living relatives. Endomicrobia, a family-level lineage of host-associated bacteria in the phylum that comprises both free-living representatives and endosymbionts of termite gut flagellates, are an excellent model to study evolution of intracellular symbionts. We reconstructed 67 metagenome-assembled genomes (MAGs) of among more than 1,700 MAGs from the gut microbiota of a wide range of termites.

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Background: Many arthropods rely on their gut microbiome to digest plant material, which is often low in nitrogen but high in complex polysaccharides. Detritivores, such as millipedes, live on a particularly poor diet, but the identity and nutritional contribution of their microbiome are largely unknown. In this study, the hindgut microbiota of the tropical millipede Epibolus pulchripes (large, methane emitting) and the temperate millipede Glomeris connexa (small, non-methane emitting), fed on an identical diet, were studied using comparative metagenomics and metatranscriptomics.

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Methane emission by terrestrial invertebrates is restricted to millipedes, termites, cockroaches, and scarab beetles. The arthropod-associated archaea known to date belong to the orders , and , and in a few cases also to non-methanogenic and . However, all major host groups are severely undersampled, and the taxonomy of existing lineages is not well developed.

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Pelomyxa is a genus of anaerobic amoebae that live in consortia with multiple prokaryotic endosymbionts. Although the symbionts represent a large fraction of the cellular biomass, their metabolic roles have not been investigated. Using single-cell genomics and transcriptomics, we have characterized the prokaryotic community associated with P.

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Termites host diverse communities of gut microbes, including many bacterial lineages only found in this habitat. The bacteria endemic to termite guts are transmitted via two routes: a vertical route from parent colonies to daughter colonies and a horizontal route between colonies sometimes belonging to different termite species. The relative importance of both transmission routes in shaping the gut microbiota of termites remains unknown.

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Most members of the family () are associated with vertebrate hosts. However, a diverse clade of uncultured, putatively free-living treponemes comprising several genus-level lineages is present in other anoxic environments. The only cultivated representative to date is Treponema zuelzerae, isolated from freshwater mud.

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The intestinal tracts of termites are abundantly colonized by a diverse assemblage of spirochetes. Most of them belong to 'termite cluster I', a monophyletic group within the radiation of the genus that occurs exclusively in termite guts. Phylogenomic analysis revealed that members of the genus are extremely diverse and represent two separate, family-level lineages: the , which comprise the majority of the validly described species, and a second lineage that comprises the remaining members of the genus , including all members of 'termite cluster I' from termites and the recently isolated from cockroaches.

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Background: Termites primarily feed on lignocellulose or soil in association with specific gut microbes. The functioning of the termite gut microbiota is partly understood in a handful of wood-feeding pest species but remains largely unknown in other taxa. We intend to fill this gap and provide a global understanding of the functional evolution of termite gut microbiota.

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The evaluation of the dizzy patient is complicated by many common pitfalls. The patient's description of symptoms and the standard neurologic examination are often nonspecific or unrevealing, and neuroimaging is most often normal. Over the past several years, research has demonstrated that a refocusing of history taking results in more reliable and diagnostically helpful information.

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Methanogens represent the final decomposition step in anaerobic degradation of organic matter, occurring in the digestive tracts of various invertebrates. However, factors determining their community structure and activity in distinct gut sections are still debated. In this study, we focused on the tropical millipede species Archispirostreptus gigas (Diplopoda, Spirostreptidae) and Epibolus pulchripes (Diplopoda, Pachybolidae), which release considerable amounts of methane.

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Spirochetes of the genus Treponema are surprisingly abundant in termite guts, where they play an important role in reductive acetogenesis. Although they occur in all termites investigated, their evolutionary origin is obscure. Here, we isolated the first representative of 'termite gut treponemes' from cockroaches, the closest relatives of termites.

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Symbiotic digestion of lignocellulose in the hindgut of higher termites is mediated by a diverse assemblage of bacteria and archaea. During a large-scale metagenomic study, we reconstructed 15 metagenome-assembled genomes of that represent two distinct lineages in subgroup 6 (formerly MCG-6) unique to termite guts. One lineage (TB2; Termitimicrobium) encodes all enzymes required for reductive acetogenesis from CO via an archaeal variant of the Wood-Ljungdahl pathway, involving tetrahydromethanopterin as C carrier and an (ADP-forming) acetyl-CoA synthase.

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Nephridiophagids are unicellular eukaryotes that parasitize the Malpighian tubules of numerous insects. Their life cycle comprises multinucleate vegetative plasmodia that divide into oligonucleate and uninucleate cells, and sporogonial plasmodia that form uninucleate spores. Nephridiophagids are poor in morphological characteristics, and although they have been tentatively identified as early-branching fungi based on the SSU rRNA gene sequences of three species, their exact position within the fungal tree of live remained unclear.

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Objective: The aim of this interlaboratory round robin test was to prove the robustness of the DIN EN ISO 6872:2019 and to identify the influence of processing and testing variations.

Methods: Each of the 12 laboratories participated (A-L) received 60 (n = 720) assigned zirconia specimens. All participants seperated the specimens from the blanks, sintered them, polished half of all specimens and performed the biaxial flexural test (DIN EN ISO 6872:2019).

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Methanogenesis is the final step in the anaerobic degradation of organic matter. The most important substrates of methanogens are hydrogen plus carbon dioxide and acetate, but also the use of methanol, methylated amines, and aromatic methoxy groups appears to be more widespread than originally thought. Except for most members of the family Methanosarcinaceae, all methylotrophic methanogens require external hydrogen as reductant and therefore compete with hydrogenotrophic methanogens for this common substrate.

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The therapeutic options to treat infections are very limited. Our aim was to evaluate the activity of sulbactam combined directly with avibactam or the ampicillin-sulbactam/ceftazidime-avibactam combination against extensively drug-resistant isolates. Extensively drug-resistant isolates (=127) collected at several South American hospitals were studied.

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Background: Because there are no head-to-head studies of the efficacy of surgical options in the treatment of medically-intractable idiopathic intracranial hypertension (IIH), procedure selection is often based on expected complications. Cerebrospinal fluid (CSF) diversion by shunting has been reported to have a 23%-67% rate of shunt failure. But these figures derive from small cohorts or studies that do not separate the complication rates of the different shunt options-ventriculoperitoneal (VP), lumboperitoneal (LP), and ventriculoatrial (VA).

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"Higher" termites have been able to colonize all tropical and subtropical regions because of their ability to digest lignocellulose with the aid of their prokaryotic gut microbiota. Over the last decade, numerous studies based on 16S rRNA gene amplicon libraries have largely described both the taxonomy and structure of the prokaryotic communities associated with termite guts. Host diet and microenvironmental conditions have emerged as the main factors structuring the microbial assemblages in the different gut compartments.

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Although mutualistic associations between animals and microbial symbionts are widespread in nature, the mechanisms that have promoted their evolutionary persistence remain poorly understood. A vertical mode of symbiont transmission (from parents to offspring) is thought to ensure partner fidelity and stabilization, although the efficiency of vertical transmission has rarely been investigated, especially in cases where hosts harbour a diverse microbial community. Here we evaluated vertical transmission rates of cellulolytic gut oxymonad and parabasalid protists in the wood-feeding termite Reticulitermes grassei.

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The symbiotic gut flagellates of lower termites form host-specific consortia composed of Parabasalia and Oxymonadida. The analysis of their coevolution with termites is hampered by a lack of information, particularly on the flagellates colonizing the basal host lineages. To date, there are no reports on the presence of oxymonads in termites of the family Stolotermitidae.

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Background: Diet is a major determinant of bacterial community structure in termite guts, but evidence of its importance in the closely related cockroaches is conflicting. Here, we investigated the ecological drivers of the bacterial gut microbiota in cockroaches that feed on lignocellulosic leaf litter.

Results: The physicochemical conditions determined with microsensors in the guts of Ergaula capucina, Pycnoscelus surinamensis, and Byrsotria rothi were similar to those reported for both wood-feeding and omnivorous cockroaches.

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Implant restoration is one of the basic treatments in dentistry today, yet implant loss from occlusal overload is still a problem. Complex biomechanical problems such as occlusal overload are often analyzed by means of the finite element method. This numerical method makes it possible to analyze in detail the influence that different loading situations have upon implants and tissues, which is a key element in optimizing these dental procedures.

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