9,376 research outputs found
At the poles across kingdoms: phosphoinositides and polar tip growth
No full textPhosphoinositides (PIs) are minor, but essential phospholipid constituents of eukaryotic membranes, and are involved in the regulation of various physiological processes. Recent genetic and cell biological advances indicate that PIs play important roles in the control of polar tip growth in plant cells. In root hairs and pollen tubes, PIs control directional membrane trafficking required for the delivery of cell wall material and membrane area to the growing tip. So far, the exact mechanisms by which PIs control polarity and tip growth are unresolved. However, data gained from the analysis of plant, fungal and animal systems implicate PIs in the control of cytoskeletal dynamics, ion channel activity as well as vesicle trafficking. The present review aims at giving an overview of PI roles in eukaryotic cells with a special focus on functions pertaining to the control of cell polarity. Comparative screening of plant and fungal genomes suggests diversification of the PI system with increasing organismic complexity. The evolutionary conservation of the PI system among eukaryotic cells suggests a role for PIs in tip growing cells in models where PIs so far have not been a focus of attention, such as fungal hyphae
Underneath the Observational Snapshot: Looking For Sense and Meaning Behind the First Impressions of a Learning Interaction
No full textEducation practitioners, including Ofsted inspectors and Teacher Educators, try to make sense of behaviour in the classroom by observing the interaction of teachers and learners. They make judgements about what is good teaching, what is bad learner behaviour and what are inclusive and effective learning experiences. This article argues that such observations are inadequate for assessing and evaluating learning behaviour and insufficient to enable teachers to develop their own personalised teaching and learning strategies and their confidence as professional teachers. The article was written in response to examples of Further Education (FE) teachers describing the college classroom as a war zone and a battlefield (Lebor, 2013). The author argues that such metaphors reinforce the notion that teachers and learners are situated at opposing sides of an education institution with differing interests. They also ignore the position of the teacher as being a learner too. The author advocates using an existentialist approach to understanding and reflecting on the learning process. She models strategies she has used herself to attempt to step outside the conventional paradigm of learning in college and create a new framework for reflecting on what is good behaviour from a teacher and good behaviour from a learner
Visualizing mitochondrial dynamics at the nanoscale
No full textAbstract The study of mitochondria is a formidable challenge for super-resolution microscopy due to their dynamic nature and complex membrane architecture. In this issue, Ren et al. introduce HBmito Crimson, a fluorogenic and photostable mitochondrial probe for STED microscopy and investigate how mitochondrial dynamics influence the spatial organization of mitochondrial DNA
Roland Stephan
No full textElna Roos
(Roland Stephan)
f. 25.11.1905 i Jakobstad
d. 1946
Elna Roos var till yrket barnträdgårdslärare. Vid sidan om detta utgav hon, under pseudonymen Roland Stephan, detektivromanen Mordet i parkhotellet (1941). Verket tillhör en tidig tradition av detektivromaner skrivna av svenskspråkiga kvinnliga författare i Finland på 1940-talet.
---Elna Roos
(Roland Stephan)
s. 25.11.1905 Pietarsaaressa
k. 1946
Elna Roos oli koulutukseltaan lastentarhanopettaja. Salanimellä Roland Stephan hän julkaisi työnsä ohella salapoliisiromaanin Mordet i parkhotellet (1941). Teos oli yksi ensimmäisistä ruotsinkielisistä naisen kirjoittamista salapoliisiromaaneista 1940-luvun Suomessa
Innenarchitektur der Zellkraftwerke: Membranfalten in Hochauflösung
No full textMitochondria are essential cellular organelles, which supply eukaryotic cells with the universal energy carrier adenosine triphosphate. These organelles feature a unique double-membrane architecture, which is formed by a smooth outer membrane and a highly folded inner membrane. Harnessing super-resolution light and electron microscopy, we investigate the role of MICOS, a large mitochondrial protein complex, in determining the complex folding of the inner membrane
Live-cell STED nanoscopy of mitochondrial cristae.
No full textMitochondria are highly dynamic organelles that exhibit a complex inner architecture. They exhibit a smooth outer membrane and a highly convoluted inner membrane that forms invaginations called cristae. Imaging cristae in living cells poses a formidable challenge for super-resolution light microscopy. Relying on a cell line stably expressing the mitochondrial protein COX8A fused to the SNAP-tag and using STED (stimulated emission depletion) nanoscopy, we demonstrate the visualization of cristae dynamics in cultivated human cells. We show that in human HeLa cells lamellar cristae are often arranged in groups separated by voids that are generally occupied by mitochondrial nucleoids
Light microscopy of mitochondria at the nanoscale.
No full textMitochondria are essential for eukaryotic life. These double-membrane organelles often form highly dynamic tubular networks interacting with many cellular structures. Their highly convoluted contiguous inner membrane compartmentalizes the organelle, which is crucial for mitochondrial function. Since the diameter of the mitochondrial tubules is generally close to the diffraction limit of light microcopy, it is often challenging, if not impossible, to visualize submitochondrial structures or protein distributions using conventional light microscopy. This renders super-resolution microscopy particularly valuable, and attractive, for studying mitochondria. Super-resolution microscopy encompasses a diverse set of approaches that extend resolution, as well as nanoscopy techniques that can even overcome the diffraction limit. In this review, we provide an overview of recent studies using super-resolution microscopy to investigate mitochondria, discuss the strengths and opportunities of the various methods in addressing specific questions in mitochondrial biology, and highlight potential future developments. Expected final online publication date for the Annual Review of Biophysics, Volume 49 is May 6, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates
Kyrgyz - Muslim - Central Asian? Recent Approaches to the Study of Kyrgyz Culture in Kyrgyzstan
No full text- …
