Search

Eukaryogenesis represented a major evolutionary transition that led to the emergence of complex cells from simpler ancestors. For several decades, the most accepted scenario involved the evolution of an independent lineage of proto-eukaryotes endowed with an endomembrane system, including a nuclear compartment, a developed cytoskeleton and phagocytosis, which engulfed the alphaproteobacterial ancestor of mitochondria. However, the recent discovery by metagenomic and cultural approaches of Asgard archaea, which harbour many genes in common with eukaryotes and are their closest relatives in phylogenomic trees, rather supports scenarios based on the symbiosis of one Asgard-like archaeon and one or more bacteria at the origin of the eukaryotic cell. Here, we review the recent discoveries that led to this conceptual shift, briefly evoking current models of eukaryogenesis and the challenges ahead to discriminate between them and to establish a detailed, plausible scenario that accounts for the evolution of eukaryotic traits from those of their prokaryotic ancestors.

Background: Applied Theatre (AT) is a relatively recently-created interdisciplinary field that includes investigation of the social and educational uses of its practices. Since its emergence as a discipline in the 1990s, research has proliferated. However, to better understand the breadth and depth of AT's social and educational applications, there is a need to review and synthesise the scientific literature in this developing area. Purpose: We sought to address this gap by providing a qualitative synthesis of relevant literature focusing on theatre as a tool for social and educational intervention with socially disadvantaged groups, capturing some of the key achievements and challenges in the field. Design and methods: A qualitative review of scientific literature published on this issue in the last decade was conducted. After obtaining an overview of the literature, we conducted a thematic analysis to identify the central themes of the research. Findings: Scientific discussion on the social and educational uses of theatre has expanded significantly in the last decade. Our thematic analysis identified the documentation of a rich multiplicity of social and educational possibilities for applying theatre to contexts of social vulnerability, including: empowerment and development of critical awareness, promotion of personal and community development, construction of spaces of recognition, development of empathetic attitudes towards human differences, and the recovery of silenced narratives. This review also uncovered a number of challenges and dilemmas inherent to the field, such as the question of power distribution in applied theatre processes or the complexities created by an instrumental vision of the arts. Conclusions: This qualitative synthesis of research demonstrates how AT, as a framework for reflection and action of an interdisciplinary nature, offers useful dialogical, creative and critical tools for generating viable alternatives in diverse social and educational contexts. The review of research draws attention to how AT may provide a platform for the recognition and participation of marginalised groups and individuals, and offer a potentially relevant mechanism for moderating social and educational inequality.

Smartphones (SMPs) play a vital role in the lives of young people and in the university classroom. There are few studies of the use of SMPs by university students, and the existing knowledge is inconsistent and lacking consensus. This article shows the validity of a theoretical model of the use of SMPs in higher education, in the context of the theory of uses and gratifications, and the knowledge gained from previous studies on the use of SMPs by adolescents. The results suggest the existence of a specific educational function for the use of SMPs in university classrooms. Despite the emergent nature of this function, the educational use of SMPs in higher education presents potential consolidation as a source of gratification and satisfaction of educational needs. Their inclusion in the everyday activity of university classrooms will require considerable effort to adapt the educational system, and the training of students and teaching staff must be improved in order to reduce possible interference in learning the communicative and expressive play functions of SMPs.

Benthic protist communities, including sand-dwelling dinoflagellates, are still poorly characterized worldwide and there is a lack of knowledge on their diversity and spatiotemporal dynamics. In this study, sediments were obtained from several coastal locations of the German Wadden Sea during the summer months of 2017 and 2018 to determine the diversity and spatiotemporal distribution of sand-dwelling dinoflagellates. The analyses consisted of light microscopy and the metabarcoding of small subunit (SSU) rRNA gene V4 region amplicons. Additionally, SSU rRNA sequences were newly obtained for 15 observed taxa included in a reference database and were used to taxonomically assign the obtained amplicon sequence variants (ASVs). The combination of morphological and molecular approaches allowed a deep characterization of dinoflagellate communities. Seventy-three morphospecies were detected by microscopy, while metabarcoding ASVs (amplicon sequence variants) were assigned to 116 species, resulting in a more comprehensive biodiversity inventory than achieved with either method alone. Pfiesteriaceae, Togula compacta and Thecadinium yashimaense predominated in the different sampling locations. Communities from Wilhelmshaven diverged from the others, consistent with its muddier sediment. A high level of resemblance was determined for the communities from each location, regardless of the sampling month and year, indicating a high summertime stability of benthic communities. Further efforts will be needed to characterize benthic protist diversity, as a first step in obtaining a complete picture of the habitat characteristics and physico-chemical conditions that influence benthic community composition. Metabarcoding and microscopy observations provide complementary results. Much of the diversity of sand-dwelling dinoflagellates is uncharacterized. Benthic dinoflagellate communities were stable at each location in summer. [ABSTRACT FROM AUTHOR]

Rhodelphidia is a recently discovered phylum within the supergroup Archaeplastida, comprising only two known representatives (Rhodelphis marinus and Rhodelphis limneticus). Despite its close phylogenetic relatedness to red algae, Rhodelphidia differ markedly by being nonphotosynthetic eukaryotrophic flagellates with gene‐ and intron‐rich genomes. Here, we describe a new freshwater Rhodelphidia species, Rhodelphis mylnikovi sp. n., strain Rhod‐M. It shows clear morphological differences with the two other Rhodelphis species, including larger cell body size, presence of two contractile vacuoles, short and blunt pseudopodia, absence of cysts, and tendency to cannibalism. 18S rRNA‐based phylogenetic analysis placed it sister to the freshwater species R. limneticus. [ABSTRACT FROM AUTHOR]

A unicellular cyanobacterium, strain VI4D9, was isolated from thermophilic microbial mats thriving in a hot spring of the Ahousaht territory of Vancouver Island, Canada, and characterized using optical and electron microscopy, genome sequencing and cultivation approaches. The cells were elongated rods (5.1 µm in length and 1.2 µm in width, on average). Their UV visible absorption spectra revealed that they contain chlorophyll a, phycocyanin and carotenoids. Transmission electron microscopy showed the presence of thylakoids concentrated on one side of the cells. The strain grew within a temperature range of 37–50°C, with an optimum growth at 45°C. Its genome had a size of 3 049 282 bp and a DNA G + C content of 51.8 mol%. The cells contained numerous intracellular spherical granules easily visible under scanning electron microscopy. Energy dispersive X-ray spectroscopy revealed that these granules were made of Ca-, Ba- and Sr-containing carbonates. A phylogenetic 16S rRNA gene tree robustly placed this strain as sister to several environmental sequences and the described species Gloeomargarita lithophora, also characterized by the possession of intracellular carbonate inclusions. We consider strain VI4D9 to represent a new Gloeomargarita species based on its marked phenotypic differences with G. lithophora, notably, its thermophilic nature and different thylakoid organization, therefore we propose the name Gloeomargarita ahousahtiae sp. nov. The type strain is VI4D9 (Culture Collection of Algae and Protozoa strain 1472/1; Laboratorio de Algas Continentales Mexico strain LAC 140). Gloeomargarita ahousahtiae is the second species described within the recently discovered order Gloeomargaritales. Gloeomargarita ahousahtiae is a new thermophilic cyanobacterium. Growth temperature and thylakoid morphology differentiate G. ahousahtiae and G. lithophora. All described Gloeomargaritales synthesize intracellular carbonate inclusions. [ABSTRACT FROM AUTHOR]

Our study aims to discover the degree of efficacy of the principal's performance in relation to the learning objectives, curriculum, and results, and explore the relationship among the perceptions of the inspectors, teachers, and management teams about the principal's efficacy in promoting students' learning. The Vanderbilt Assessment of Leadership in Education (VAL-ED) questionnaire was applied. Contingency analyses were calculated. We concluded that the three sectors considered the principal's work to be effective in actions related to the learning objectives, curriculum planning, and responsibility for the outcomes.