[Effects of mid-palatal suture opening and midfacial bony structure changes induced by maxillary skeletal expansion in adults].

PURPOSE: To analyze the opening of mid-palatal suture, transverse changes in dental and dentoalveolar measurements and shift of midfacial bony structures induced by maxillary skeletal expansion (MSE) with cone-beam CT (CBCT), and to evaluate the effect of maxillary skeletal expansion and its influence on adjacent bony structures in adults. METHODS: The study sample consisted of 12 adult patients with maxillary transverse deficiency (4 males, 8 females) at a mean age of (21.17±4.13) years old. All patients were treated with MSE. After treatment, the posterior crossbite was corrected, and the width of the maxillary arch was achieved the optimal width. Pre- and post-treatment CBCT exams were taken before and after MSE treatment. Multiplanar coronal and axial slices obtained from CBCT images were used to measure the changes in transverse widths, angular changes and tooth inclination with Dolphin Imaging 11.9. SPSS 26.0 software package was used for statistical analysis. RESULTS: After MSE treatment, the anterior nasal spine width increased by (2.38±1.01) mm, posterior nasal spine width increased by (2.25±1.08) mm (P<0.01). The inter-crown and inter-apex distance at the first molar increased by (5.56±1.38) mm and (4.14±1.29) mm, respectively (P<0.01). No significant difference was seen in terms of tooth inclination of the first molar(P>0.05). Pterygoid process angle, pterygoid process width, anterior inter-maxillary distance, upper and lower inter-zygomatic distance were significantly larger after treatment (P<0.01), while the inter-temporal distance and bilateral zygomaticomaxillary angle remained unchanged(P>0.05). CONCLUSIONS: MSE has a favorable effect in adult patients with parallel skeletal expansion of the mid-palatal suture achieved after expansion. The teeth present with certain buccal inclination but show no significant movement relative to the alveolar bone. The midfacial bony structures also shift in three-dimensional under the effect of the expansion force.

Exposure to nanoplastics disturbs the gut microbiome in the soil oligochaete Enchytraeus crypticus.

Microplastics are emerging pollutants that have recently aroused considerable concern but most toxicological studies have focused on marine biota, with little investigation of the influence of microplastics on terrestrial ecosystems. Here, we fed the soil oligochaete Enchytraeus crypticus with oatmeal containing 0, 0.025, 0.5, and 10% (dry weight basis) nano-polystyrene (0.05-0.1 µm particle size) to elucidate the impact of microplastics on the growth and gut microbiome of Enchytraeus crypticus. We observed a significant reduction of weight in the animals fed 10% polystyrene and an increase in the reproduction of those fed 0.025%. More importantly, using 16S rRNA amplification and high-throughput sequencing we found a significant shift in the microbiome of those fed 10% microplastics with significant decreases in the relative abundance of the families Rhizobiaceae, Xanthobacteraceae and Isosphaeraceae. These families contain key microbes that contribute to nitrogen cycling and organic matter decomposition.

Recurrent horizontal transfer of arsenite methyltransferase genes facilitated adaptation of life to arsenic.

The toxic metalloid arsenic has been environmentally ubiquitous since life first arose nearly four billion years ago and presents a challenge for the survival of all living organisms. Its bioavailability has varied dramatically over the history of life on Earth. As life spread, biogeochemical and climate changes cyclically increased and decreased bioavailable arsenic. To elucidate the history of arsenic adaptation across the tree of life, we reconstructed the phylogeny of the arsM gene that encodes the As(III) S-adenosylmethionine (SAM) methyltransferase. Our results suggest that life successfully moved into arsenic-rich environments in the late Archean Eon and Proterozoic Eon, respectively, by the spread of arsM genes. The arsM genes of bacterial origin have been transferred to other kingdoms of life on at least six occasions, and the resulting domesticated arsM genes promoted adaptation to environmental arsenic. These results allow us to peer into the history of arsenic adaptation of life on our planet and imply that dissemination of genes encoding diverse adaptive functions to toxic chemicals permit adaptation to changes in concentrations of environmental toxins over evolutionary history.