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Mounting evidence suggests that terrestrialization of plants started in streptophyte green algae, favoured by their dual existence in freshwater and subaerial/terrestrial environments. Here, we present the genomes of Mesostigma viride and Chlorokybus atmophyticus, two sister taxa in the earliest-diverging clade of streptophyte algae dwelling in freshwater and subaerial/terrestrial environments, respectively. We provide evidence that the common ancestor of M. viride and C. atmophyticus (and thus of streptophytes) had already developed traits associated with a subaerial/terrestrial environment, such as embryophyte-type photorespiration, canonical plant phytochrome, several phytohormones and transcription factors involved in responses to environmental stresses, and evolution of cellulose synthase and cellulose synthase-like genes characteristic of embryophytes. Both genomes differed markedly in genome size and structure, and in gene family composition, revealing their dynamic nature, presumably in response to adaptations to their contrasting environments. The ancestor of M. viride possibly lost several genomic traits associated with a subaerial/terrestrial environment following transition to a freshwater habitat.

Genome analysis of the pico-eukaryotic marine green alga Prasinoderma coloniale CCMP 1413 unveils the existence of a novel phylum within green plants (Viridiplantae), the Prasinodermophyta, which diverged before the split of Chlorophyta and Streptophyta. Structural features of the genome and gene family comparisons revealed an intermediate position of the P. coloniale genome (25.3 Mb) between the extremely compact, small genomes of picoplanktonic Mamiellophyceae (Chlorophyta) and the larger, more complex genomes of early-diverging streptophyte algae. Reconstruction of the minimal core genome of Viridiplantae allowed identification of an ancestral toolkit of transcription factors and flagellar proteins. Adaptations of P. coloniale to its deep-water, oligotrophic environment involved expansion of light-harvesting proteins, reduction of early light-induced proteins, evolution of a distinct type of C4 photosynthesis and carbon-concentrating mechanism, synthesis of the metal-complexing metabolite picolinic acid, and vitamin B1, B7 and B12 auxotrophy. The P. coloniale genome provides first insights into the dawn of green plant evolution.

In plants, two independent serine biosynthetic pathways, the photorespiratory and glycolytic phosphoserine (PS) pathways, have been postulated. Although the photorespiratory pathway is well characterized, little information is available on the function of the PS pathway in plants. Here, we present a detailed characterization of phosphoglycerate dehydrogenases (PGDHs) as components of the PS pathway in Arabidopsis thaliana. All PGDHs localize to plastids and possess similar kinetic properties, but they differ with respect to their sensitivity to serine feedback inhibition. Furthermore, analysis of pgdhi and phosphoserine phosphatase mutants revealed an embryo-lethal phenotype and PGDH1-silenced lines were inhibited growth. Metabolic analyses of PGDH1-silenced lines grown under ambient and high CO₂ conditions indicate a direct link between PS biosynthesis and ammonium assimilation. In addition, we obtained several lines of evidence for an interconnection between PS and tryptophan biosynthesis, because the expression of PGDH1 and PHOSPHOSERINE AMINOTRANSFERASE1 regulated by MYB51 and MYB34, two activators of tryptophan biosynthesis. Moreover, the concentration of tryptophan-derived glucosinolates and auxin were reduced in PGDH1-silenced plants. In essence, our results provide evidence for a vital function of PS biosynthesis for plant development and metabolism.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Background Point-of-care ultrasound (POCUS) is rapidly gaining prominence in various clinical settings. As its use becomes more widespread, there is a growing need for comprehensive ultrasound training in medical education to ensure that future healthcare professionals are proficient in this essential diagnostic tool. Objective This study is the first attempt by the University of Bonn to seamlessly integrate ultrasound courses and the use of ultrasound devices into the regular activities of final year medical students and to evaluate the usage of these devices. Methods A total of forty students in their practical year were provided with a hendheld ultrasound device for a period of four months. During this time, they were invited to take part in eight optional ultrasound courses in which they acquired images and those images were rated using a specially developed rating system. At the end of the tertial, students were able to take part in a voluntary survey on the use of the equipment. Results Participation in the optional ultrasound courses was well received, with the Introduction and FAST module drawing the largest number of participants (29). Among the ultrasound images acquired by students, those of the lungs obtaining the highest rating, with 18.82 (SD ± 4.30) points out of 23 points, while the aorta and vena cava images scored lowest, with an average of 16.62 (SD ± 1.55) points. The overall mean score for all images was 17.47 (SD ± 2.74). Only 21 students responded to the survey. Of the participating students, 67% used the device independently four times or fewer during the tertial. Conclusion The study aimed to enhance the BI-POCUS curriculum by improving students' ultrasound skills during their practical year. However, device usage was lower than expected, with most students using it only once a month or less. This raises concerns about the justification of the effort and resources. Future initiatives will focus on technical improvements, better login data provision, and closer monitoring of usage and progress, emphasizing the need for practical ultrasound training in medical education.

Background As ultrasound is one of the most utilized imaging procedures in clinical practice in Germany, its integration into undergraduate medical education is imperative. Thereby, the limited availability of qualified instructors is a major challenge. Peer tutors, who are trained to instruct their peers collaboratively, could resolve staff constraints. This systematic review explores the literature on peer teaching in undergraduate ultrasound education, aiming to provide an overview of methodologies, outcomes, and peer teacher training concepts. Methods Following the PRISMA guidelines, a systematic literature review was conducted on the subject of peer teaching in undergraduate ultrasound education. Using PubMed and Google Scholar as databases, studies in English or German involving training concepts for peer teachers in undergraduate ultrasound education, published up to November 21, 2023, were included. Data extraction of original studies followed the PICOS schema with special respect to didactic concepts of peer tutor training programs and the effectiveness of peer teachers compared to faculty instructors. A modified version of the Newcastle–Ottawa Scale (NOS) was used to assess the quality of included studies. Results Finally, the search resulted in 20 relevant original studies, including 16 studies exploring peer teacher training concepts. Predominantly, peer teachers studied in their 4th year of medical school and on average one year further compared to their students. Peer teacher training was integrated into curricula by course-based concepts (93.8%) and internships (50.0%). Didactic modalities varied, encompassing laboratory rotations including the scanning of patients, the scanning of fellow students, lectures, and didactic training. The median training duration was about ten days. Of six comparative studies, five found peer-assisted learning to be comparably effective and one even better than faculty-led courses. Conclusion Despite the growing amount of literature underlining the effectiveness and wide application of peer teaching in ultrasound education, training concepts stay heterogenous without a standardized system for training and qualifying peer teachers. Developing comprehensive guidelines for peer tutor education could increase acceptance and recognition of peer-assisted learning and ensure minimum training standards.

As a widely accessible, cost-effective, and safe imaging tool, obstetric and gynecologic (OB/GYN) ultrasound (ULS) plays a vital role in diagnostics and patient care. With its growing relevance, the demand for comprehensive education in this field increases. The objective of this work was to outline the current state of OB/GYN ULS education. A scoping literature search was performed until May 2023 using the medical database PubMed according to PRISMA guidelines. Using specific keywords, relevant publications were filtered. Subsequently, abstracts were independently reviewed by two authors and the inclusion of each publication was assessed against pre-defined key search terms. Full-text versions of the included publications were scrutinized and pertinent information was extracted. In this review, 126 articles from the literature search matched the inclusion criteria and were investigated. Our findings revealed a diverse range of course concepts and programs, a lot of them not meeting the expectations of trainees and international guidelines. OB/GYN ULS training primarily targets residents, yet opportunities for early exposure and continuing education are underexplored. International organizations, such as the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) and the German Society for Ultrasound in Medicine (DEGUM) have proposed guidelines and curricula for standardized training. However, adoption remains varied. There is an emergent need to innovate teaching methods. There is consensus that standardizing OB/GYN ULS curricula could enhance training quality and streamline the creation of new programs, ultimately improving patient care. Further research is needed to define the most effective strategies for curriculum development and implementation.

The aim of this study was to measure, characterize, and compare the time-resolved three-dimensional wall kinematics of the ascending and the abdominal aorta. Comprehensive description of aortic wall kinematics is an important issue for understanding its physiological functioning and early detection of adverse changes. Data on the three-dimensional, dynamic cyclic deformation of the aorta in vivo are scarce. Either most imaging techniques available are too slow to capture aortic wall motion (CT, MRI) or they do not provide three-dimensional geometry data. Three-dimensional volume data sets of ascending and abdominal aortae of male healthy subjects (25.5 [24.5, 27.5] years) were acquired by use of a commercial echocardiography system with a temporal resolution of 11–25 Hz. Longitudinal and circumferential strain, twist, and relative volume change were determined by use of a commercial speckle tracking algorithm and in-house software. The kinematics of the abdominal aorta is characterized by diameter change, almost constant length and unidirectional, either clockwise or counter clockwise twist. In contrast, the ascending aorta undergoes a complex deformation with alternating clockwise and counterclockwise twist. Length and diameter changes were in the same order of magnitude with a phase shift between both. Longitudinal strain and its phase shift to circumferential strain contribute to the proximal aorta’s Windkessel function. Complex cyclic deformations are known to be highly fatiguing. This may account for increased degradation of components of the aortic wall and therefore promote aortic dissection or aneurysm formation.