The parasitic nematode Strongyloides sp. infects a large range of host species, including ungulates, carnivores, non-human primates, and humans, causing mostly asymptomatic chronic infections. Strongyloides nasua represents a previously understudied and poorly described species, which is capable of causing fatal hyperinfection in its host. We report the first genomic description and comprehensive morphological analysis of S. nasua , which caused fatal strongyloidiasis in two coatis ( Nasua nasua ) at a wildlife rescue centre in Peru, South America. The two animals were housed in the centre for a few months prior to clinical signs occurring, with infection ultimately leading to a fatal outcome. Post-mortem examination showed cachectic animals, inflamed intestine with enlarged Peyer’s patches and mesenteric lymph nodes. Histological analysis revealed hyperinfection, with severe parasitic enteritis with the presence of numerous nematodes at various developmental stages entrapped in the intestinal mucosa. Direct microscopic examination of the nematodes revealed key morphological characteristics of parasitic female S. nasua . Combining 18S rRNA and cox1 genotyping together with short- and long-read whole genome sequencing, our data revealed that S. nasua represents a member of a potentially new group in the genus Strongyloides , closely related to S. stercoralis and S. procyonis. The S. nasua genome was associated with expansion of acetylcholinesterases, embryonic development and developmental processes and contraction of orthogroups associated with immune and antimicrobial responses, indicating potential diversification or specialisation of associated processes in S. nasua .

ABSTRACT Background Dental crowns have surface pollutants after their manufacturing. We know that these pollutants can be a source of peri‐implant inflammation for some cases. This study aimed to compare two dental crowns cleaning methods that are simple and quick to apply in the dental lab. Objectives To characterize qualitatively and quantitatively the pollution of transmucosal parts of zirconia monolithic crowns after supra‐mucosal glazing in the lab and to compare the efficacy of steam versus ultrasonic cleaning protocols. Material and Methods Eighteen customized zirconia monolithic crowns were divided into two groups of 9 crowns receiving a different cleaning protocol. The first group was treated with steam cleaning, whereas the second group was initially rubbed with a sterile compress soaked in a detergent and then cleaned in three successive ultrasonic baths containing a detergent, sterile water, and 70% ethanol. The presence and nature of the contaminants were investigated by BSE‐SEM and energy‐dispersive X‐ray spectroscopy microanalysis. Results Organic (e.g., paint, sweat) and inorganic (e.g., zirconia fragments, silica, and metals) were identified on the surface of the zirconia crown before the cleaning treatments. At baseline, pollutants cover 0.51% ± 0.26% of the total area. This percentage dropped, respectively, to 0.02% ± 0.03% after steam cleaning ( p < 0.0001) and to 0.02% ± 0.01 after the ultrasonic cleaning protocol ( p = 0.0026). No difference was observed between the two decontamination techniques ( p > 0.9999), but the variance in the steam group was higher compared to the ultrasound group ( p = 0.0042). Conclusions Both protocols allowed the cleaning of the transmucosal parts of the zirconia crowns to an extent of 99.98% of the studied surface. However, the ultrasound technique displayed less variability in the removal of residual pollutants and therefore should be preferred.

Most micro-organisms remain unculturable under standard laboratory conditions, limiting our understanding of microbial diversity and ecological interactions. One major cause of this uncultivability is the loss of access to essential cross-fed metabolites when bacteria are removed from their natural communities. During a bioprospecting campaign targeting actinomycetes of an Apis mellifera beehive, we identified five isolates (DT32, DT45T, DT55, DT59 and DT194) that required co-cultivation for growth recovery, suggesting a dependence on microbial interactions in their native habitat. Whole-genome sequencing and phylogenetic analysis positioned these isolates within a distinct lineage of Micromonosporaceae, separate from the five officially recognized clades of the Micromonospora genus. A combination of microscopic, chemotaxonomic and physiological characterizations further supported their uniqueness. Notably, they exhibited high auxotrophy, being unable to use all carbon sources tested, likely due to genome reduction (4.6 Mbp) compared to other Micromonosporaceae. Pangenomic comparisons with their closest Micromonospora relatives revealed gene losses in key metabolic pathways, including the glyoxylate bypass and the Entner-Doudoroff pathway, which may explain their metabolic reliance. These findings reveal a highly specialized, ecologically adapted lineage with deep evolutionary divergence and further support microbial interdependence isolation strategies to explore the microbial dark matter. We propose Melissospora conviva as a novel genus and species within the Actinomycetota phylum, with isolate DT45T as the representative type species and type strain, which has been deposited in public collections under the accession numbers DSM 117791 and LMG 33580.

Summary: Deciphering the fossil record of cyanobacteria is crucial to understand their role in the chemical and biological evolution of the early Earth. They profoundly modified the redox conditions of early ecosystems more than 2.4 Ga ago, the age of the Great Oxidation Event (GOE), and provided the ancestor of the chloroplast by endosymbiosis, leading the diversification of photosynthetic eukaryotes. Here, we analyze the morphology, ultrastructure, chemical composition, and metals distribution of Polysphaeroides filiformis from the 1040–1006 Ma Mbuji-Mayi Supergroup (DR Congo). We evidence trilaminar and bilayered ultrastructures for the sheath and the cell wall, respectively, and the preservation of Ni-tetrapyrrole moieties derived from chlorophyll in intracellular inclusions. This approach allows an unambiguous interpretation of P. filiformis as a branched and multiseriate photosynthetic cyanobacterium belonging to the family of Stigonemataceae. It also provides a possible minimum age for the emergence of multiseriate true branching nitrogen-fixing and probably heterocytous cyanobacteria.

Apple scab, caused by the hemibiotrophic fungus Venturia inaequalis, is currently the most common and damaging disease in apple orchards. Two strains of V. inaequalis (S755 and Rs552) with different sensitivities to azole fungicides and the bacterial metabolite fengycin were compared to determine the mechanisms responsible for these differences. Antifungal activity tests showed that Rs552 had reduced sensitivity to tebuconazole and tetraconazole, as well as to fengycin alone or in a binary mixture with other lipopeptides (iturin A, pumilacidin, lichenysin). S755 was highly sensitive to fengycin, whose activity was close to that of tebuconazole. Unlike fengycin, lipopeptides from the iturin family (mycosubtilin, iturin A) had similar activity on both strains, while those from the surfactin family (lichenysin, pumilacidin) were not active, except in binary mixtures with fengycin. The activity of lipopeptides varies according to their family and structure. Analyses to determine the difference in sensitivity to azoles (which target the CYP51 enzyme involved in the ergosterol biosynthesis pathway) showed that the reduced sensitivity in Rs552 is linked to (i) a constitutive increased expression of the Cyp51A gene caused by insertions in the upstream region and (ii) greater efflux by membrane pumps with the involvement of ABC transporters. Microscopic observations revealed that fengycin, known to interact with plasma membranes, induced morphological and cytological changes in cells from both strains. Sterol and phospholipid analyses showed a higher level of ergosta-7,22-dien-3-ol and a lower level of PI(C16:0/C18:1) in Rs552 compared with S755. These differences could therefore influence the composition of the plasma membrane and explain the differential sensitivity of the strains to fengycin. However, the similar antifungal activities of mycosubtilin and iturin A in the two strains indirectly indicate that sterols are probably not involved in the fengycin resistance mechanism. This leads to the conclusion that different mechanisms are responsible for the difference in susceptibility to azoles or fengycin in the strains studied.

Purpose: To validate the effectiveness of a simplified ultrasonic cleaning protocol to clean customized abutments, and to investigate the percentage of pollutants on customized abutments provided by the implant company and the additional effect of dental laboratory manipulations. Materials and Methods: A total of 24 customized abutments were divided in two groups, 12 returning from the implant company and 12 others returning from the dental laboratory. In each group, there were 6 zirconia (Zr0(2)) abutments and 6 titanium (Ti) abutments. For each condition, half of the samples were cleaned with the experimental protocol, and the others were left as delivered by the company. The two-step cleaning protocol consisted of mechanical treatment with a sterile compress soaked in a detergent over the transgingival part of the abutment, followed by three successive ultrasound baths for two minutes/bath. The presence of pollutants was quantified using scanning electron microscopy. Results: The suggested cleaning method allowed to significantly decrease the quantity of pollutants (P = .0006). The abutments returning from the dental laboratory were significantly more polluted than those coming directly from the implant company (P = .0043). The cleaning effect was highly significant in both groups (P < .0001). The quantity of pollutants before cleaning were similar in the titanium and in the zirconia groups and the cleaning effect was highly significant in both groups (P = .0009). Conclusions: The cleaning protocol tested was successful on the customized abutments from each group. Intl Prosthodont2024;37:e136-e148. doi: 10.11607/ijp.8328

Metal oxides containing La, Mn, and Co cations can catalyze oxygen reduction reactions (ORRs) in electrochemical processes. However, these materials require carbon support and optimal interactions between both compounds to be active. In this work, two approaches to prepare composites of La-Mn-Co-based compounds over carbon xerogel were developed. Using sol-gel methods, either the metal-based material was deposited on the existing carbon xerogel or vice versa. The metal oxide selected was the LaMn0.7Co0.3O3 perovskite, which has good catalytic behavior and selectivity towards direct ORRs. All the as-prepared composites were tested for ORRs in alkaline liquid electrolytes and characterized by diverse physicochemical techniques such as XRD, XPS, SEM, or N2 adsorption. Although the perovskite structure either decomposed or failed to form using those in situ methods, the materials exhibited great catalytic activity, which can be ascribed to the strengthening of the interactions between oxides and the carbon support via C-O-M covalent bonds and to the formation of new active sites such as the MnO/Co heterointerfaces. Moreover, Co-Nx-C species are formed during the synthesis of the metal compounds over the carbon xerogel. These species possess a strong catalytic activity towards ORR. Therefore, the composites formed by synthesizing metal compounds over the carbon xerogel exhibit the best performance in the ORR, which can be ascribed to the presence of the MnO/Co heterointerfaces and Co-Nx-C species and the strong interactions between both compounds. Moreover, the small nanoparticle size leads to a higher number of active sites available for the reaction.

Aegagropiles are conglomerations of fibre debris from Posidonia oceanica meadows that are frequently found along Mediterranean beaches, but the plant organ from which these fibres arise remains unknown. In this study, a histological comparison of P. oceanica organs from 3 shoots with the structure of aegagropile fibres showed that most of them arise from leaf sheaths and rhizomes, suggesting that they are degradation products from the “matte” rather than from the leaf litter, which is mainly composed of detached leaf blades. Moreover, fungal hyphae, micro-sclerotia and typical degradation traces were found in the peripheral tissues of living P. oceanica organs, as well as in degrading aegagropiles. We assume, by comparing Vohník’s observations and the observations made in this study, that these endophytic fungi and degradation traces might be attributed to a dark septate endophyte (DSE) in the Aigialaceae (Pleosporales), Posidoniomyces atricolor, which was recently described as an endosymbiont in P. oceanica roots. It constitutes one of the most important microorganisms by abundance that degrade P. oceanica tissues within the matte and give rise to the different fibre types in aegagropiles. This study shows that the proliferation of fungi causes organ degradation in Posidonia, starting early in living P. oceanica plants, continuing in the matte and, probably, in the leaf litter. The DSE plays a much more important role than that of a simple plant endosymbiont; its omnipresence within P. oceanica (and the degradation of the middle lamella and cell death during proliferation) causing the degradation of various Posidonia organs also contributes to the enrichment of the ‘matte’ compartment of this ecosystem, notably favouring nitrogen retention in its chitinous walls.

Facial trauma, bone resection due to cancer, periodontal diseases, and bone atrophy following tooth extraction often leads to alveolar bone defects that require bone regeneration in order to restore dental function. Guided bone regeneration using synthetic biomaterials has been suggested as an alternative approach to autologous bone grafts. The efficiency of bone substitute materials seems to be influenced by their physico-chemical characteristics; however, the debate is still ongoing on what constitutes optimal biomaterial characteristics. The purpose of this study was to develop an empirical model allowing the assessment of the bone regeneration potential of new biomaterials on the basis of their physico-chemical characteristics, potentially giving directions for the design of a new generation of dental biomaterials. A quantitative data set was built composed of physico-chemical characteristics of seven commercially available intra-oral bone biomaterials and their in vivo response. This empirical model allowed the identification of the construct parameters driving optimized bone formation. The presented model provides a better understanding of the influence of driving biomaterial properties in the bone healing process and can be used as a tool to design bone biomaterials with a more controlled and custom-made composition and structure, thereby facilitating and improving the clinical translation.

Biominerals are organic–mineral composites formed by living organisms. They are the hardest and toughest tissues in those organisms, are often polycrystalline, and their mesostructure (which includes nano‐ and microscale crystallite size, shape, arrangement, and orientation) can vary dramatically. Marine biominerals may be aragonite, vaterite, or calcite, all calcium carbonate (CaCO 3 ) polymorphs, differing in crystal structure. Unexpectedly, diverse CaCO 3 biominerals such as coral skeletons and nacre share a similar characteristic: Adjacent crystals are slightly misoriented. This observation is documented quantitatively at the micro‐ and nanoscales, using polarization‐dependent imaging contrast mapping (PIC mapping), and the slight misorientations are consistently between 1° and 40°. Nanoindentation shows that both polycrystalline biominerals and abiotic synthetic spherulites are tougher than single‐crystalline geologic aragonite. Molecular dynamics (MD) simulations of bicrystals at the molecular scale reveal that aragonite, vaterite, and calcite exhibit toughness maxima when the bicrystals are misoriented by 10°, 20°, and 30°, respectively, demonstrating that slight misorientation alone can increase fracture toughness. Slight‐misorientation‐toughening can be harnessed for synthesis of bioinspired materials that only require one material, are not limited to specific top‐down architecture, and are easily achieved by self‐assembly of organic molecules (e.g., aspirin, chocolate), polymers, metals, and ceramics well beyond biominerals.

Spearing mantis shrimps are aggressive crustaceans using specialized appendages with sharp spikes to capture fishes with a fast movement. Each spike is a biological tool that have to combine high toughness, as required by the initial impact with the victim, with high stiffness and strength, to ensure sufficient penetration while avoid breaking. We performed a multimodal analysis to uncover the design strategies of this harpoon based on chitin. We found that the spike is a slightly hooked hollow beam with the outer surface decorated by serrations and grooves to enhance cutting and interlocking. The cuticle of the spike resembles a multilayer composite: an outer heavily mineralized, stiff and hard region (with average indentation modulus and hardness of 68 and 3 GPa), providing high resistance to contact stresses, is combined with a less mineralized region, which occupies a large fraction of the cuticle (up to 50%) and features parallel fibers oriented longitudinally, enhancing stiffness and strength. A central finding of our work is the presence of a tiny interphase (less than 10 μm in width) based on helical fibers and showing a spatial modulation in mechanical properties, which has the critical task to integrate the stiff but brittle outer layer with the more compliant highly anisotropic parallel fiber region. We highlighted the remarkable ability of this helicoidal region to stop nanoindentation-induced cracks. Using three-dimensional multimaterial printing to prototype spike-inspired composites, we showed how the observed construction principles can not only hamper damage propagation between highly dissimilar layers (resulting in composites with the helical interphase absorbing 50% more energy than without it) but can also enhance resistance to puncture (25% increase in the force required to penetrate the composites with a blunt tool). Such findings may provide guidelines to design lightweight harpoons relying on environmentally friendly and recyclable building blocks.

On Earth, the circulation of Fe-rich fluids in hydrothermal environments leads to characteristic iron mineral deposits, reflecting the pH and redox chemical conditions of the hydrothermal system, and is often associated with chemotroph microorganisms capable of deriving energy from chemical gradients. On Mars, iron-rich hydrothermal sites are considered to be potentially important astrobiological targets for searching evidence of life during exploration missions, such as the Mars 2020 and the ExoMars 2022 missions. In this study, an extinct hydrothermal chimney from the Jaroso hydrothermal system (SE Spain), considered an interesting geodynamic and mineralogical terrestrial analog for Mars, was analyzed using Raman spectroscopy, X-ray diffraction, and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The sample consists of a fossil vent in a Miocene shallow-marine sedimentary deposit composed of a marl substrate, an iron-rich chimney pipe, and a central space filled with backfilling deposits and vent condensates. The iron crust is particularly striking due to the combined presence of molecular and morphological indications of a microbial colonization, including mineral microstructures (e.g., stalks, filaments), iron oxyhydroxide phases (altered goethite, ferrihydrite), and organic signatures (carotenoids, organopolymers). The clear identification of pigments by resonance Raman spectroscopy and the preservation of organics in association with iron oxyhydroxides by Raman microimaging demonstrate that the iron crust was indeed colonized by microbial communities. These analyses confirm that Raman spectroscopy is a powerful tool for documenting the habitability of such historical hydrothermal environments. Finally, based on the results obtained, we propose that the ancient iron-rich hydrothermal pipes should be recognized as singular terrestrial Mars analog specimens to support the preparatory work for robotic in situ exploration missions to Mars, as well as during the subsequent interpretation of data returned by those missions.

The acquisition of photosynthesis is a fundamental step in the evolution of eukaryotes. However, few phototrophic organisms are unambiguously recognized in the Precambrian record. The in situ detection of metabolic byproducts in individual microfossils is the key for the direct identification of their metabolisms. Here, we report a new integrative methodology using synchrotron-based X-ray fluorescence and absorption. We evidence bound nickel-geoporphyrins moieties in low-grade metamorphic rocks, preserved in situ within cells of a ~1 Gyr-old multicellular eukaryote, Arctacellularia tetragonala . We identify these moieties as chlorophyll derivatives, indicating that A. tetragonala was a phototrophic eukaryote, one of the first unambiguous algae. This new approach, applicable to overmature rocks, creates a strong new proxy to understand the evolution of phototrophy and diversification of early ecosystems.

Abstract The hardest and toughest tissues formed by living organisms are organic-mineral composites termed biominerals 1,2. When they are crystalline, their mesostructure includes the nano- and micro-scale crystallite size, shape, arrangement, and orientation. Mesostructures vary enormously across marine CaCO3 biominerals (aragonite, vaterite, calcite) because they result from divergent evolution: biominerals were formed long after organisms diverged from one another 3,4. Despite such diversity, CaCO3 marine biominerals share a convergent character: adjacent crystals are similarly oriented 5-32. The reason for such convergence is unclear. Here, we show with quantitative, precise measurements at the nanoscale that the slight misorientation is consistently between 1°-40° in diverse biominerals. Can this slight misorientation confer a desirable materials property and therefore an evolutionary advantage to the forming organisms? We test and confirm this hypothesis with nanoindentation in diverse biominerals, geologic aragonite, and in abiotic, slightly misoriented, synthetic spherulites. Molecular dynamics (MD) simulations of bicrystals reveal that aragonite, vaterite, calcite, exhibit toughness peaks when they are misoriented by 10°, 20°, 30°, respectively, demonstrating that slight misorientation alone increases crack deflection and therefore fracture toughness. Slight misorientation, along with other previously known and co-existing toughening mechanisms, was selected repeatedly and convergently, during the course of evolution, to postpone fracture and thus provide organisms with competitive advantage. We anticipate slight misorientation-toughening to be a starting point for more sophisticated materials synthesis and additive manufacturing in many fields. Compared to previously known toughening mechanisms, in fact, the advantages of slight misorientation are that it can and does occur in synthetic materials, it requires one material only and no specific top-down architecture, it is easily achieved by self-assembly of organic molecules (e.g. aspirin, chocolate), polymers, metals, and ceramics 29 well beyond biominerals.

Among piranhas, different species are able to produce sounds but not all of them use the same mechanism. In all species, the sound‐producing muscle originates on the second vertebra, but the insertion differs. Pygopristis denticulata can produce two kinds of pulsed sounds emitted in trains. Its sound production mechanism is mainly based on a muscle bundle that inserts between the two first ribs. In Catoprion mento , the anterior part of the sonic muscle inserts directly on the swim bladder. The most derived species ( Serrasalmus and Pygocentrus ) make all harmonic tonal sounds. Their sonic muscles constitute a single functional unit transversally surrounding the swim bladder. This study aims to study the ultrastructure of sonic muscles in nine species from these four genera. Epaxial muscles were compared with sonic muscles, and the sonic muscles of the different species were compared between them. Results confirmed ultrastructure modifications in the sonic muscles in comparison to epaxial muscles. Fibers of the sonic muscle are thinner and possess a thicker subsarcolemmal ring housing mitochondria. In sonic muscles, myofibrils are also proportionally less abundant, and their sarcomeres are longer and thinner. Some of these differences allows to separate basal species (e.g., P. denticulata ) from more derived species (genera Pygocentrus and Serrasalmus ) and supposedly support the observed differences in the acoustic abilities.

Stomatopoda is a crustacean order including sophisticated predators called spearing and smashing mantis shrimps that are separated from the well-studied Eumalacotraca since the Devonian. The spearing mantis shrimp has developed a spiky dactyl capable of impaling fishes or crustaceans in a fraction of second. In this high velocity hunting technique, the spikes undergo an intense mechanical constraint to which their exoskeleton (or cuticle) has to be adapted. To better understand the spike cuticle internal architecture and composition, electron microscopy, X-ray microanalysis and Raman spectroscopy were used on the spikes of 7 individuals (collected in French Polynesia and Indonesia), but also on parts of the body cuticle that have less mechanical stress to bear. In the body cuticle, several specificities linked to the group were found, allowing to determine the basic structure from which the spike cuticle has evolved. Results also highlighted that the body cuticle of mantis shrimps could be a model close to the ancestral arthropod cuticle by the aspect of its biological layers (epi- and procuticle including exo- and endocuticle) as well as by the Ca-carbonate/phosphate mineral content of these layers. In contrast, the spike cuticle exhibits a deeply modified organization in four functional regions overprinted on the biological layers. Each of them has specific fibre arrangement or mineral content (fluorapatite, ACP or phosphate-rich Ca-carbonate) and is thought to assume specific mechanical roles, conferring appropriate properties on the entire spike. These results agree with an evolution of smashing mantis shrimps from primitive stabbing/spearing shrimps, and thus also allowed a better understanding of the structural modifications described in previous studies on the dactyl club of smashing mantis shrimps.

Aegagropiles are round-shaped conglomerations of Posidonia oceanica debris commonly found along the coasts of the Mediterranean Sea. This study presents a detailed description of the composition of aegagropiles in terms of their internal organisation in different layers (and the orientation of the fibres in these layers), the proportion of constituent elements (fibres and minerals) and the histological (by way of microscopic observations) nature of all of these aegagropiles elements. The aim of this work is to take a detailed interest in the structure of the aegagropiles of Posidonia oceanica and to determine the process that forms them. Aegagropiles are an assemblage of two types of debris from the P. oceanica meadow: (1) plant-based: fibres more or less degraded from P. oceanica shoots (leaves and rhizomes) and (2) mineral particles such as silicates and biotic Ca-carbonate debris. On the basis of structural and compositional observations, we proposed an elucidation of the cycle in several phases: initiation of a “roll” by aggregation of litter fibres and sand in the ripple marks, growth, breakdown of the roll into small balls (microbial and mechanical degradation) and export of aegagropiles down (into the abyss) or on to the beaches. Calculations estimate that considering its density of 0.2 g/cm3, an aegagropile represents the accumulation of fibres from approximately 25 shoots of P. oceanica.

Cyanobacteria, a major phylum among the Bacteria domain, played an important role in the evolution of early Life and Earth by strongly changing the redox conditions of early ecosystems, since at least the Great Oxidation Event (GOE, ~2.4 Ga). Despite their importance, their unambiguous fossil record is scarce. Only three microfossil taxa are interpreted as cyanobacteria with certainty. Therefore, it is essential to characterize new biosignatures of cyanobacteria for a better identification of their microfossil counterparts. Newly identified fossils from well-dated geological successions will then enable a better calibration of molecular clocks of cyanobacteria, thereby allowing a better understanding of their diversification, and their role in Earth and life evolution. Here we studied the morphology, ultrastructure, chemical composition and metals distribution of one microfossil taxon identified as a cyanobacterium , Polysphaeroides filiformis, from the ~1 Ga Mbuji-Mayi Supergroup (Congo Basin, DR Congo). P. filiformis consists of spheroidal vesicles surrounded by a common branching sheath. The observation of the microfossil ultrastructure reveals a trilaminar structure for the sheath. The SR-XRF detection of homogeneous distribution of Ni within intracellular