Amoebozoan testate amoebae illuminate the diversity of heterotrophs and the complexity of ecosystems throughout geological time.

Heterotrophic protists are vital in Earth's ecosystems, influencing carbon and nutrient cycles and occupying key positions in food webs as microbial predators. Fossils and molecular data suggest the emergence of predatory microeukaryotes and the transition to a eukaryote-rich marine environment by 800 million years ago (Ma). Neoproterozoic vase-shaped microfossils (VSMs) linked to Arcellinida testate amoebae represent the oldest evidence of heterotrophic microeukaryotes. This study explores the phylogenetic relationship and divergence times of modern Arcellinida and related taxa using a relaxed molecular clock approach. We estimate the origin of nodes leading to extant members of the Arcellinida Order to have happened during the latest Mesoproterozoic and Neoproterozoic (1054 to 661 Ma), while the divergence of extant infraorders postdates the Silurian. Our results demonstrate that at least one major heterotrophic eukaryote lineage originated during the Neoproterozoic. A putative radiation of eukaryotic groups (e.g., Arcellinida) during the early-Neoproterozoic sustained by favorable ecological and environmental conditions may have contributed to eukaryotic life endurance during the Cryogenian severe ice ages. Moreover, we infer that Arcellinida most likely already inhabited terrestrial habitats during the Neoproterozoic, coexisting with terrestrial Fungi and green algae, before land plant radiation. The most recent extant Arcellinida groups diverged during the Silurian Period, alongside other taxa within Fungi and flowering plants. These findings shed light on heterotrophic microeukaryotes' evolutionary history and ecological significance in Earth's ecosystems, using testate amoebae as a proxy.

High above the rest: standing behaviors in the amoebae of Sappinia and Thecamoeba.

Many terrestrial microbes have evolved cell behaviors that help them rise above their substrate, often to facilitate dispersal. One example of these behaviors is found in the amoebae of Sappinia pedata, which actively lift most of their cell mass above the substrate, known as standing. This standing behavior was first described in S. pedata in the 1890s from horse dung isolates but never molecularly characterized from dung. Our study expands this understanding, revealing the first molecularly confirmed S. pedata from herbivore dung in Mississippi, USA, and describing a new species, Sappinia dangeardi n. sp., with larger trophozoite cells. Additionally, we isolated another standing amoeba, Thecamoeba homeri n. sp., from soil, exhibiting a previously unreported "doughnut shape" transient behavior. In S. dangeardi n. sp., we discovered that standing is likely triggered by substrate drying, and that actin filaments actively localize in the "stalk" to support the standing cells, as observed through confocal microscopy. While the purpose of standing behaviors has not been investigated, we hypothesize it is energetically expensive and therefore a significant evolutionary strategy in these organisms. Overall, this study emphasizes behavioral adaptations to terrestrial environments within Amoebozoa, stressing the importance of diverse laboratory conditions that replicate natural habitats.

Molecular phylogenetic analyses support the validity of Ceratiomyxa porioides (Amoebozoa, Eumycetozoa) at species level.

The frequently encountered macroscopic slime molds of the genus Ceratiomyxa have long been recognized by mycologists and protistologists for hundreds of years. These organisms are amoebozoan amoebae that live and grow inside and on the surface of decaying wood. When conditions are favorable, they form subaerial sporulating structures called fruiting bodies which take on a variety of forms. These forms are typically some arrangement of column and/or branches, but one is uniquely poroid, forming folds instead. Originally, this poroid morphology was designated as its own species. However, it was not always clear what significance fruiting body morphology held in determining species. Currently, Ceratiomyxa fruticulosa var. porioides, the poroid form, is considered a taxonomic variety of Ceratiomyxa fruticulosa based on morphological designation alone. Despite its long history of observation and study, the genus Ceratiomyxa has been paid little molecular attention to alleviate these morphological issues. We have obtained the first transcriptomes of the taxon C. fruticulosa var. porioides and found single gene phylogenetic and multigene phylogenomic support to separate it from C. fruticulosa. This provides molecular evidence that fruiting body morphology does correspond to species level diversity. Therefore, we formally raise Ceratiomyxa porioides to species level.

Living in the cracks: Two novel genera of Variosea (Amoebozoa) discovered on an urban sidewalk.

Biological soil crusts represent a rich habitat for diverse and complex eukaryotic microbial communities. A unique but extremely common habitat is the urban sidewalk and its cracks that collect detritus. While these habitats are ubiquitous across the globe, little to no work has been conducted to characterize protists found there. Amoeboid protists are major predators of bacteria and other microbial eukaryotes in these microhabitats and therefore play a substantial ecological role. From sidewalk crack soil crusts, we have isolated three naked amoebae with finely tapered subpseudopodia, and a simple life cycle consisting of a trophic amoeba and a cyst stage. Using a holistic approach including light, electron, and fluorescence microscopy as well as phylogenetics using the ribosomal small subunit rRNA gene and phylogenomics using 230 nuclear genes, we find that these amoeboid organisms fail to match any previously described eukaryote genus. However, we determined the amoebae belong to the amoebozoan lineage Variosea based on phylogenetics. The molecular analyses place our isolates in two novel genera forming a grade at the base of the variosean group Protosteliida. These three novel varioseans among two novel genera and species are herein named "Kanabo kenzan" and "Parakanabo toge."

A digitally driven manufacturing process for high resolution patterning of cell formations.

This paper presents the engineering and validation of an enabling technology that facilitates new capabilities in in vitro cell models for high-throughput screening and tissue engineering applications. This is conducted through a computerized system that allows the design and deposition of high-fidelity microscale patterned coatings that selectively alter the chemical and topographical properties of cell culturing surfaces. Significantly, compared to alternative methods for microscale surface patterning, this is a digitally controlled and automated process thereby allowing scientists to rapidly create and explore an almost infinite range of cell culture patterns. This new capability is experimentally validated across six different cell lines demonstrating how the precise microscale deposition of these patterned coatings can influence spatiotemporal growth and movement of endothelial, fibroblast, neuronal and macrophage cells. To further demonstrate this platform, more complex patterns are then created and shown to guide the behavioral response of colorectal carcinoma cells.

A Phase III, Randomized, Double-Blind, Placebo-Controlled Trial Assessing the Efficacy and Safety of Viloxazine Extended-Release Capsules in Adults with Attention-Deficit/Hyperactivity Disorder.

BACKGROUND AND OBJECTIVE: Attention-deficit/hyperactivity disorder is a neurodevelopmental disorder that typically begins in childhood and often persists into adulthood. Recent phase III trials have demonstrated the efficacy and safety of viloxazine extended-release capsules (viloxazine ER; Qelbree®) in pediatrics (6-17 years of age). The aim of this study was to evaluate the efficacy and safety of viloxazine ER in adults with attention-deficit/hyperactivity disorder. METHODS: This was a phase III, randomized, double-blind, placebo-controlled, two-arm trial in adults (18-65 years of age) with attention-deficit/hyperactivity disorder. Eligible subjects were randomized 1:1 to viloxazine ER (flexible dose of 200-600 mg/day) or matched placebo. The primary efficacy endpoint was the change from baseline at end of study (week 6) in the Adult ADHD Investigator Symptom Rating Scale (AISRS) total score. The key secondary endpoint was the change from baseline at end of study in the Clinical Global Impressions-Severity of Illness (CGI-S) score. Additional secondary outcome measures included the AISRS Inattention and Hyperactivity/Impulsivity subscales, the Behavior Rating Inventory of Executive Function-Adult (BRIEF-A), the Generalized Anxiety Disorder-7 Item (GAD-7), and the Clinical Global Impressions-Improvement (CGI-I); each was analyzed at end of study. Responder rates on CGI scales and the AISRS were also assessed. RESULTS: A total of 374 subjects were randomized. At end of study, the mean viloxazine ER dose was 504 mg. The reduction in the change from baseline at end of study AISRS total score (least-square means ± standard error) was significantly greater in subjects treated with viloxazine ER (-15.5 ± 0.91) compared with placebo (-11.7 ± 0.90), p = 0.0040. The reduction in the CGI-S score was also significantly greater in subjects treated with viloxazine ER (-1.4 ± 0.10) compared with placebo (-1.0 ± 0.10), p = 0.0023. The viloxazine ER group demonstrated significantly greater improvements in the AISRS Inattention (p = 0.0015) and Hyperactivity/Impulsivity (p = 0.0380) subscales, the CGI-I (p = 0.0076), and the BRIEF-A Global Executive Composite (p = 0.0468) and Metacognition Index (p = 0.0100). Analysis of categorical secondary endpoints revealed that the viloxazine ER group had a significantly higher AISRS 30% response rate compared with placebo (p = 0.0395); all other comparisons were not significant. Many treatment effects (including the primary and key secondary endpoints) were significant by week 2. The most common treatment-related adverse events that occurred in ≥5% of subjects receiving viloxazine ER were insomnia (14.8%), fatigue (11.6%), nausea (10.1%), decreased appetite (10.1%), dry mouth (9.0%), and headache (9.0%). Viloxazine ER was well tolerated, with a 9.0% discontinuation rate due to adverse events compared with 4.9% in the placebo group. CONCLUSIONS: Treatment with viloxazine ER resulted in a statistically significant improvement in primary and key secondary endpoints, indicating improvements in attention-deficit/hyperactivity disorder symptomology, executive function, and overall clinical illness severity in adults. Viloxazine ER was well tolerated at the tested doses in adults with attention-deficit/hyperactivity disorder. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT04016779.

Attention-deficit/hyperactivity disorder (ADHD) is a condition characterized by inattention (difficulty maintaining focus), and/or impulsiveness/hyperactivity. In 2021, a nonstimulant medication called viloxazine ER (brand name: Qelbree^®) received US FDA-approval for ADHD in children and adolescents (aged 6 to 17 years), based on efficacy and safety demonstrated in clinical trials. Here we present results of a phase 3, randomized, double-blind, placebo-controlled, clinical trial that enrolled 374 adults with ADHD. In this trial, half the patients received viloxazine ER, and half received placebo (identical capsule without active ingredient). Medication doses ranged from 200­600 mg/day, based on symptom response and presence of side effects. To reduce bias, patients and investigators did not know which medication the patient was receiving. The primary measure of efficacy was the Adult ADHD Investigator Symptom Rating Scale (AISRS), a standardized questionnaire rating presence and severity of patient-reported ADHD symptoms. At the end of the 6-week trial, participants receiving viloxazine ER showed greater improvement in ADHD symptoms according to AISRS than those receiving placebo. Improvement was seen in both the Inattentive and Impulsive/Hyperactive components of ADHD and in other study measures, including a measure of behaviors called Executive Function. Viloxazine ER was generally safe and well-tolerated in the trial. The most common side effects were insomnia (14.8%), fatigue (11.6%), and nausea (10.1%). Overall, 9.0% of patients receiving viloxazine and 5% receiving placebo left the trial because of side effects. Due to these positive results, the US FDA recently approved viloxazine ER to treat adults with ADHD.

A Phase 3 Placebo-Controlled Trial of Once-Daily 400-mg and 600-mg SPN-812 (Viloxazine Extended-Release) in Adolescents with ADHD.

Objectives: Three Phase 3 trials have demonstrated the efficacy and safety of SPN-812 in pediatric subjects with ADHD. Here, we report the results of a fourth trial. Methods: Eligible adolescent subjects (N = 297) were randomized to SPN-812 (400- or 600-mg/day) or placebo. The primary efficacy endpoint was change from baseline (CFB) at end of study (EOS) in the ADHD Rating Scale-5 (ADHD-RS-5) Total score. Statistical analyses included sequential testing for multiple treatment comparisons. Key secondary endpoints included: Clinical Global Impression-Improvement (CGI-I) score at EOS and CFB at EOS in the Conners 3-Parent Short Form (Conners 3-PS) Composite T-score and Weiss Functional Impairment Rating Scale-Parent (WFIRS-P) Total average score. Results: The CFB at EOS ADHD-RS-5 Total score (least square [LS] means ± SE) for 400-mg/day, 600-mg/day SPN-812, and placebo was -18.3 ± 1.36, -16.7 ± 1.39, and -13.2 ± 1.38, respectively. The difference vs. placebo was statistically significant only for the 400-mg/day SPN-812 treatment group (600 mg/day: p = 0.0712; 400 mg/day: p = 0.0082). Neither dose could be considered superior to placebo due to the use of statistical method of sequential testing. Significant improvements were observed on a number of secondary endpoints. SPN-812 was well tolerated at both doses, with <5% discontinuation rate due to adverse events. Conclusions: Treatment with 400- but not 600-mg/day SPN-812 resulted in statistically significant improvement in the primary endpoint. The negative result seen in the 600-mg/day SPN-812 group was likely due to an unusually high placebo response. Safety data were consistent across all doses in the SPN-812 trials.

A Phase 3, Placebo-Controlled Trial of Once-Daily Viloxazine Extended-Release Capsules in Adolescents With Attention-Deficit/Hyperactivity Disorder.

PURPOSE: This phase 3 clinical trial evaluated the efficacy and safety of viloxazine extended-release capsules (VLX-ER) as a monotherapy for attention-deficit/hyperactivity disorder (ADHD) in adolescents (12-17 years). METHODS: Eligible subjects (n = 310) were randomized to receive once-daily 200 and 400 mg VLX-ER, or placebo for 6 weeks. The primary efficacy end point was change from baseline (CFB) at the end of study (EOS) in ADHD Rating Scale-5 Total score. Key secondary end points were Clinical Global Impression-Improvement score at EOS, CFB at EOS in Conners 3-Parent Short Form Composite T-score, and CFB at EOS in Weiss Functional Impairment Rating Scale-Parent Total average score. RESULTS: In the 200-mg/d and 400-mg/d VLX-ER treatment groups, a significant improvement was found in the CFB at EOS in ADHD Rating Scale-5 Total (P = 0.0232, P = 0.0091) and Inattention (P = 0.0424, P = 0.0390) and Hyperactivity/Impulsivity (P = 0.0069, P = 0.0005) subscale scores versus placebo. The Clinical Global Impression-Improvement score was significantly improved at EOS in the 200-mg/d and 400-mg/d VLX-ER groups versus placebo (P = 0.0042, P = 0.0003). The Conners 3-Parent Short Form composite T-score and Weiss Functional Impairment Rating Scale-Parent Total average score exhibited improvement in both VLX-ER groups; however, the difference versus placebo was not statistically significant. The most common treatment-related adverse events were somnolence, headache, decreased appetite, nausea, and fatigue. The adverse event-related discontinuation rates were <5% in all groups. CONCLUSIONS: Viloxazine extended-release demonstrated statistically significant and clinically meaningful improvement in ADHD symptoms in adolescents and was generally well tolerated.

Once-Daily SPN-812 200 and 400 mg in the treatment of ADHD in School-aged Children: A Phase III Randomized, Controlled Trial.

PURPOSE: SPN-812 (viloxazine extended-release) is under investigation for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. This Phase III study evaluated the efficacy and tolerability of SPN-812 200 and 400 mg once daily in children 6-11 years of age with ADHD. METHODS: Patients were randomly assigned to receive SPN-812 200 mg, SPN-812 400 mg, or placebo, once daily for 8 weeks (including ≤3 weeks titration period). The primary efficacy endpoint was the change from baseline (CFB) in ADHD Rating Scale (RS)-5 Total score at end of study (EOS). Key secondary endpoints included Clinical Global Impression-Improvement (CGI-I) score at EOS, CFB in Conners 3-Parent Short Form (PS) composite T-score at EOS, and CFB in Weiss Functional Impairment Rating Scale-Parent (WFIRS-P) Total average score at EOS. FINDINGS: A total of 313 patients were enrolled, with 301 in the intent-to-treat population (194 boys, 107 girls; mean age [SD], 8.4 [1.7] years). At EOS, the CFBs in ADHD-RS-5 Total score and CGI-I score were significantly improved with both 200- and 400-mg/d SPN-812 versus placebo (ADHD-RS-5, P = 0.0038 and 0.0063, respectively; CGI-I, P = 0.0028 and 0.0099). At EOS, the CFB in Conners 3-PS composite T-score was significantly improved with 200- (P = 0.0064), but not 400-mg/d (P = 0.0917), SPN-812 compared to placebo. No significant difference between the groups was found in WFIRS-P Total average score. The rate of discontinuations due to adverse events in both SPN-812 treatment groups combined was <5%. IMPLICATIONS: SPN-812 200 and 400 mg once daily was associated with improvements in ADHD symptoms in school-aged children and was generally well tolerated. ClinicalTrials.gov identifier: NCT03247543.