scholarly journals The Hyperoxic-Hypoxic Paradox

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 958 ◽  
Author(s):  
Amir Hadanny ◽  
Shai Efrati
Keyword(s):  
Cellular Level ◽  
Metabolic Changes ◽  
Regenerative Processes ◽  
Cellular Mechanisms ◽  
Absolute Level ◽  
Free Oxygen ◽  
Oxygen Levels ◽  
Cellular Processes ◽  
Low Levels ◽  
Oxygen Physiology

Effective metabolism is highly dependent on a narrow therapeutic range of oxygen. Accordingly, low levels of oxygen, or hypoxia, are one of the most powerful inducers of gene expression, metabolic changes, and regenerative processes, including angiogenesis and stimulation of stem cell proliferation, migration, and differentiation. The sensing of decreased oxygen levels (hypoxia) or increased oxygen levels (hyperoxia), occurs through specialized chemoreceptor cells and metabolic changes at the cellular level, which regulate the response. Interestingly, fluctuations in the free oxygen concentration rather than the absolute level of oxygen can be interpreted at the cellular level as a lack of oxygen. Thus, repeated intermittent hyperoxia can induce many of the mediators and cellular mechanisms that are usually induced during hypoxia. This is called the hyperoxic-hypoxic paradox (HHP). This article reviews oxygen physiology, the main cellular processes triggered by hypoxia, and the cascade of events triggered by the HHP.

scholarly journals Life with Oxidative Stress

2012 ◽  
Vol 33 (4) ◽  
pp. 509-528 ◽  
Author(s):  
Dorota Gurda ◽  
Anna M. Kietrys ◽  
Aleksandra Szopa ◽  
Tomasz Twardowski
Keyword(s):  
Oxidative Stress ◽  
Cellular Level ◽  
Enzymatic Antioxidants ◽  
Oxygen Species ◽  
Abiotic Stress Response ◽  
Biotic And Abiotic Stress ◽  
Ros Scavenging ◽  
Cellular Mechanisms ◽  
Cellular Processes ◽  
Long Time

Incomplete oxygen reduction gives rise to reactive oxygen species (ROS). For a long time they have been considered unwelcome companions of aerobic metabolism. Organisms using oxygen developed several systems of ROS scavenging with enzymatic and non enzymatic antioxidants, which allow them control the cellular level of oxygen derived from free radicals. It is well established nowadays that ROS are not necessarily negative byproducts, but they also play an important role in cellular mechanisms. They are involved in many regular cellular processes in all aerobic organisms. When the antioxidant system is overcome and the balance between ROS production and scavenging is disrupted, oxidative stress occurs. It has been reported that oxidative stress may be linked to some human diseases and is also involved in biotic and abiotic stress response in plants.

scholarly journals Whole-Body Regeneration in Sponges: Diversity, Fine Mechanisms, and Future Prospects

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 506
Author(s):  
Alexander Ereskovsky ◽  
Ilya E. Borisenko ◽  
Fyodor V. Bolshakov ◽  
Andrey I. Lavrov
Keyword(s):  
Single Species ◽  
Whole Body ◽  
Phylogenetic Position ◽  
Main Body ◽  
Regenerative Processes ◽  
Cellular Mechanisms ◽  
Different Types ◽  
Dissociated Cells ◽  
Shed Light ◽  
Regeneration Processes

While virtually all animals show certain abilities for regeneration after an injury, these abilities vary greatly among metazoans. Porifera (Sponges) is basal metazoans characterized by a wide variety of different regenerative processes, including whole-body regeneration (WBR). Considering phylogenetic position and unique body organization, sponges are highly promising models, as they can shed light on the origin and early evolution of regeneration in general and WBR in particular. The present review summarizes available data on the morphogenetic and cellular mechanisms accompanying different types of WBR in sponges. Sponges show a high diversity of WBR, which principally could be divided into (1) WBR from a body fragment and (2) WBR by aggregation of dissociated cells. Sponges belonging to different phylogenetic clades and even to different species and/or differing in the anatomical structure undergo different morphogeneses after similar operations. A common characteristic feature of WBR in sponges is the instability of the main body axis: a change of the organism polarity is described during all types of WBR. The cellular mechanisms of WBR are different across sponge classes, while cell dedifferentiations and transdifferentiations are involved in regeneration processes in all sponges. Data considering molecular regulation of WBR in sponges are extremely scarce. However, the possibility to achieve various types of WBR ensured by common morphogenetic and cellular basis in a single species makes sponges highly accessible for future comprehensive physiological, biochemical, and molecular studies of regeneration processes.

scholarly journals Maternal Uterine Vascular Remodeling During Pregnancy

Physiology ◽  
2009 ◽  
Vol 24 (1) ◽  
pp. 58-71 ◽  
Author(s):  
George Osol ◽  
Maurizio Mandala
Keyword(s):  
Extracellular Matrix ◽  
Blood Flow ◽  
Vascular Remodeling ◽  
Normal Pregnancy ◽  
Uterine Blood Flow ◽  
Growth And Remodeling ◽  
Cellular Mechanisms ◽  
Cellular Processes ◽  
Uteroplacental Blood Flow ◽  
Uterine Circulation

Sufficient uteroplacental blood flow is essential for normal pregnancy outcome and is accomplished by the coordinated growth and remodeling of the entire uterine circulation, as well as the creation of a new fetal vascular organ: the placenta. The process of remodeling involves a number of cellular processes, including hyperplasia and hypertrophy, rearrangement of existing elements, and changes in extracellular matrix. In this review, we provide information on uterine blood flow increases during pregnancy, the influence of placentation type on the distribution of uterine vascular resistance, consideration of the patterns, nature, and extent of maternal uterine vascular remodeling during pregnancy, and what is known about the underlying cellular mechanisms.

Tight junctions

1998 ◽  
Vol 111 (5) ◽  
pp. 541-547 ◽  
Author(s):  
M.S. Balda ◽  
K. Matter
Keyword(s):  
Endothelial Cells ◽  
Cell Growth ◽  
Tight Junctions ◽  
Diffusion Barrier ◽  
Basolateral Membrane ◽  
Intercellular Junctions ◽  
Cellular Level ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Membrane Components

Tight junctions are the most apical intercellular junctions of epithelial and endothelial cells and create a regulatable semipermeable diffusion barrier between individual cells. On a cellular level, they form an intramembrane diffusion fence that restricts the intermixing of apical and basolateral membrane components. In addition to these well defined functions, more recent evidence suggests that tight junctions are also involved in basic cellular processes like the regulation of cell growth and differentiation.

scholarly journals A phosphoinositide-binding cluster in cavin1 acts as a molecular sensor for cavin1 degradation

2015 ◽  
Vol 26 (20) ◽  
pp. 3561-3569 ◽  
Author(s):  
Vikas A. Tillu ◽  
Oleksiy Kovtun ◽  
Kerrie-Ann McMahon ◽  
Brett M. Collins ◽  
Robert G. Parton
Keyword(s):  
Proteasomal Degradation ◽  
Resting Cells ◽  
Coat Proteins ◽  
Cellular Processes ◽  
Molecular Sensor ◽  
Lysine Residues ◽  
Low Levels ◽  
Membrane Stretching ◽  
Signaling Modules ◽  
Site Release

Caveolae are abundant surface organelles implicated in a range of cellular processes. Two classes of proteins work together to generate caveolae: integral membrane proteins termed caveolins and cytoplasmic coat proteins called cavins. Caveolae respond to membrane stress by releasing cavins into the cytosol. A crucial aspect of this model is tight regulation of cytosolic pools of cavin under resting conditions. We now show that a recently identified region of cavin1 that can bind phosphoinositide (PI) lipids is also a major site of ubiquitylation. Ubiquitylation of lysines within this site leads to rapid proteasomal degradation. In cells that lack caveolins and caveolae, cavin1 is cytosolic and rapidly degraded as compared with cells in which cavin1 is associated with caveolae. Membrane stretching causes caveolar disassembly, release of cavin complexes into the cytosol, and increased proteasomal degradation of wild-type cavin1 but not mutant cavin1 lacking the major ubiquitylation site. Release of cavin1 from caveolae thus leads to exposure of key lysine residues in the PI-binding region, acting as a trigger for cavin1 ubiquitylation and down-regulation. This mutually exclusive PI-binding/ubiquitylation mechanism may help maintain low levels of cytosolic cavin1 in resting cells, a prerequisite for cavins acting as signaling modules following release from caveolae.

5-HT Prolongs Ventral Root Bursting Via Presynaptic Inhibition of Synaptic Activity During Fictive Locomotion in Lamprey

2005 ◽  
Vol 93 (2) ◽  
pp. 980-988 ◽  
Author(s):  
Eric J. Schwartz ◽  
Tatyana Gerachshenko ◽  
Simon Alford
Keyword(s):  
Synaptic Transmission ◽  
Presynaptic Inhibition ◽  
Cellular Level ◽  
Ventral Horn ◽  
Pattern Generation ◽  
Ventral Root ◽  
Synaptic Activity ◽  
Fictive Locomotion ◽  
Cellular Mechanisms ◽  
Bath Application

Locomotor pattern generation is maintained by integration of the intrinsic properties of spinal central pattern generator (CPG) neurons in conjunction with synaptic activity of the neural network. In the lamprey, the spinal locomotor CPG is modulated by 5-HT. On a cellular level, 5-HT presynaptically inhibits synaptic transmission and postsynaptically inhibits a Ca2+-activated K+ current responsible for the slow afterhyperpolarization (sAHP) that follows action potentials in ventral horn neurons. To understand the contribution of these cellular mechanisms to the modulation of the spinal CPG, we have tested the effect of selective 5-HT analogues against fictive locomotion initiated by bath application of N-methyl-d-aspartate (NMDA). We found that the 5-HT1D agonist, L694-247, dramatically prolongs the frequency of ventral root bursting. Furthermore, we show that L694-247 presynaptically inhibits synaptic transmission without altering postsynaptic Ca2+ -activated K+ currents. We also confirm that 5-HT inhibits synaptic transmission at concentrations that modulate locomotion. To examine the mechanism by which selective presynaptic inhibition modulates the frequency of fictive locomotion, we performed voltage- and current-clamp recordings of CPG neurons during locomotion. Our results show that 5-HT decreases glutamatergic synaptic drive within the locomotor CPG during fictive locomotion. Thus we conclude that presynaptic inhibition of neurotransmitter release contributes to 5-HT–mediated modulation of locomotor activity.

scholarly journals Cell Tracking for Organoids: Lessons From Developmental Biology

2021 ◽  
Vol 9 ◽  
Author(s):  
Max A. Betjes ◽  
Xuan Zheng ◽  
Rutger N. U. Kok ◽  
Jeroen S. van Zon ◽  
Sander J. Tans
Keyword(s):  
Cell Tracking ◽  
Cellular Level ◽  
Model Systems ◽  
Great Promise ◽  
Cellular Processes ◽  
The Past ◽  
Fluorescent Markers ◽  
Lineage Trees ◽  
Microscopy Techniques ◽  
Organizational Principles

Organoids have emerged as powerful model systems to study organ development and regeneration at the cellular level. Recently developed microscopy techniques that track individual cells through space and time hold great promise to elucidate the organizational principles of organs and organoids. Applied extensively in the past decade to embryo development and 2D cell cultures, cell tracking can reveal the cellular lineage trees, proliferation rates, and their spatial distributions, while fluorescent markers indicate differentiation events and other cellular processes. Here, we review a number of recent studies that exemplify the power of this approach, and illustrate its potential to organoid research. We will discuss promising future routes, and the key technical challenges that need to be overcome to apply cell tracking techniques to organoid biology.

scholarly journals Perubahan nilai laktat serum dan nilai leukosit pasca penanganan pasien multitrauma

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Jimmy Koan ◽  
Laurens T. B. Kalesaran ◽  
Heber B. Sapan
Keyword(s):  
Blood Lactate ◽  
Analytical Study ◽  
Early Stage ◽  
Cellular Level ◽  
Metabolic Changes ◽  
T Test ◽  
Laboratory Markers ◽  
The Mean ◽  
Paired T Test

Abstract: Available laboratory markers in the early stage of injury are very helpful for the clinicians to predict the diturbances in cellular level concerning prevention of early decompensation, therefore, vital condition of the patient can improve faster. Lactate and leucocyte levels are assumed as sensitive markers of metabolic changes that occur at the time of injury. This study aimed to obtain the changes of lactate and leukocyte levels in multitraumatic patients after resusitation at Prof. Dr. R. D. Kandou Hospital Manado from August to September 2015. This was an observational analytical study. The results showed that there were 36 multitraumatic patients in this study, consisted of 27 males and 9 females. One patient died during this study. The mean decrease of blood lactate was 1.4611 mmol/L, meanwhile, of leukocytes was 5582.2000/mm3. The paired T test showed very significant changes of blood lactate and leukocyte levels (P < 0.001) after resusitation. Conclusion: Achievement of resusitation and improvement in cellular level could be monitored by using lactate and leukocyte levels after resusitation of multitraumatic patients although the definitive aim of the trauma was not final yet.Kata kunci: lactate, leukocyte, multitraumatic patientsAbstrak: Tersedianya penanda laboratorik pada fase awal cedera dapat memudahkan klinisi memrediksi kelainan yang terjadi di tingkat sel untuk mencegah terjadinya fase dekompensasi secara dini sehingga dapat memperbaiki kondisi vital pasien dengan segera. Kadar laktat dan jumlah leukosit telah lama dianggap sebagai salah satu penanda yang sensitif terhadap perubahan metabolisme yang terjadi saat cedera. Penelitian ini bertujuan untuk mengetahui perubahan nilai serum laktat dan leukosit darah yang terjadi pada pasien multitrauma setelah penanganan di RSUP Prof. Dr. R. D. Kandou Manado sejak bulan Agustus sampai dengan September 2015. Jenis penelitian ini observasional analitik dengan desain potong lintang. Hasil penelitian memperlihatkan terdapat 36 pasien multitrauma, terdiri dari 27 laki-laki dan 9 perempuan. Selama penelitian didapatkan 1 pasien meninggal saat penanganan. Pada pasca penanganan, rerata penurunan nilai asam laktat darah sebesar 1,4611 mmol/L dan nilai leukosit sebesar 5582,2000/mm3. Hasil uji T berpasangan memperlihatkan perubahan nilai laktat darah dan leukosit pasca penanganan yang sangat bermakna (P < 0,001). Simpulan: Tercapainya resusitasi dan perbaikan di tingkat sel dapat dimonitor dari nilai laktat dan leukosit darah pasca penanganan pasien multitrauma walaupun penanganan belum sampai pada tujuan definitif trauma.Kata kunci: asam laktat, leukosit, multitrauma

scholarly journals Arabidopsis ALIX is required for the endosomal localization of the deubiquitinating enzyme AMSH3

2015 ◽  
Vol 112 (40) ◽  
pp. E5543-E5551 ◽  
Author(s):  
Kamila Kalinowska ◽  
Marie-Kristin Nagel ◽  
Kaija Goodman ◽  
Laura Cuyas ◽  
Franziska Anzenberger ◽  
...  
Keyword(s):  
Cellular Level ◽  
Deubiquitinating Enzymes ◽  
Interacting Protein ◽  
Endosomal Sorting ◽  
Cellular Processes ◽  
Late Endosomes ◽  
Knockout Mutants ◽  
Important Regulator

Ubiquitination is a signal for various cellular processes, including for endocytic degradation of plasma membrane cargos. Ubiquitinating as well as deubiquitinating enzymes (DUBs) can regulate these processes by modifying the ubiquitination status of target protein. Although accumulating evidence points to the important regulatory role of DUBs, the molecular basis of their regulation is still not well understood. Associated molecule with the SH3 domain of signal transduction adaptor molecule (STAM) (AMSH) is a conserved metalloprotease DUB in eukaryotes. AMSH proteins interact with components of the endosomal sorting complex required for transport (ESCRT) and are implicated in intracellular trafficking. To investigate how the function of AMSH is regulated at the cellular level, we carried out an interaction screen for the Arabidopsis AMSH proteins and identified the Arabidopsis homolog of apoptosis-linked gene-2 interacting protein X (ALIX) as a protein interacting with AMSH3 in vitro and in vivo. Analysis of alix knockout mutants in Arabidopsis showed that ALIX is essential for plant growth and development and that ALIX is important for the biogenesis of the vacuole and multivesicular bodies (MVBs). Cell biological analysis revealed that ALIX and AMSH3 colocalize on late endosomes. Although ALIX did not stimulate AMSH3 activity in vitro, in the absence of ALIX, AMSH3 localization on endosomes was abolished. Taken together, our data indicate that ALIX could function as an important regulator for AMSH3 function at the late endosomes.

Sign in / Sign up

Export Citation Format

Share Document