Functions of inorganic polyphosphates in eukaryotic cells: a coat of many colours

2014 ◽  
Vol 42 (1) ◽  
pp. 98-102 ◽  
Author(s):  
Cristina Azevedo ◽  
Adolfo Saiardi
Keyword(s):  
High Energy ◽  
Linear Polymer ◽  
Detection Methods ◽  
Eukaryotic Cells ◽  
Inorganic Polyphosphates ◽  
Inorganic Polyphosphate ◽  
Structural Functions ◽  
Higher Eukaryotes ◽  
Living Organisms ◽  
And Function

PolyP (inorganic polyphosphate) is a linear polymer of tens to hundreds of orthophosphate residues linked by high-energy phosphoanhydride bonds. This polymer is present in all living organisms from bacteria to mammals. Until recently, most of the studies on polyP have focused on its function in prokaryotes. In prokaryotes, polyP has been implicated in many unrelated processes ranging from basic metabolism to structural functions. However, polyP analysis and function in higher eukaryotes has been gaining momentum recently. In the present review, we mainly aim to discuss the proposed intracellular functions of polyP in higher eukaryotes and its detection methods.

scholarly journals Inorganic polyphosphate in mammals: where's Wally?

2020 ◽  
Vol 48 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Yann Desfougères ◽  
Adolfo Saiardi ◽  
Cristina Azevedo
Keyword(s):  
Mammalian Cells ◽  
Biosynthetic Pathway ◽  
High Energy ◽  
Detection Methods ◽  
Polyp Detection ◽  
Inorganic Polyphosphate ◽  
Mammalian Enzyme ◽  
Higher Eukaryotes ◽  
Low Sensitivity ◽  
Current Detection

Inorganic polyphosphate (polyP) is a ubiquitous polymer of tens to hundreds of orthophosphate residues linked by high-energy phosphoanhydride bonds. In prokaryotes and lower eukaryotes, both the presence of polyP and of the biosynthetic pathway that leads to its synthesis are well-documented. However, in mammals, polyP is more elusive. Firstly, the mammalian enzyme responsible for the synthesis of this linear biopolymer is unknown. Secondly, the low sensitivity and specificity of available polyP detection methods make it difficult to confidently ascertain polyP presence in mammalian cells, since in higher eukaryotes, polyP exists in lower amounts than in yeast or bacteria. Despite this, polyP has been given a remarkably large number of functions in mammals. In this review, we discuss some of the proposed functions of polyP in mammals, the limitations of the current detection methods and the urgent need to understand how this polymer is synthesized.

scholarly journals Understanding Cell Biology

2019 ◽  
Vol 1 (1) ◽  
pp. 39-45
Author(s):  
Prem Swaroop Adhikarla ◽  
Pavithra Bhavanasi ◽  
Raj Sekhar Bollapragada
Keyword(s):  
Cell Biology ◽  
Cell Metabolism ◽  
Genetic Material ◽  
Reducing Power ◽  
Eukaryotic Cells ◽  
Complex Molecules ◽  
Robert Hooke ◽  
Living Things ◽  
Living Organisms ◽  
And Function

The cell is the structural and functional unit of all living organisms and is sometimes called the "building block of life.” All living things are made from one or more cells. A cell is the simplest unit of life and they are responsible for keeping an organism alive and functioning. Almost every different type of cell contains genetic material, a membrane and cytoplasm. The most basic categorization of Earth’s organisms is determined by different types of cells. All cells can be divided into one of two classifications: prokaryotic cells and eukaryotic cells. Prokaryotic cells are found in bacteria and archaea. Eukaryotic cells are found in organisms from the domain Eukaryota which includes animals, plants, fungi and protists. Cell metabolism is the process by which individual cells process nutrient molecules. Metabolism has two distinct divisions: catabolism, in which the cell breaks down complex molecules to produce energy and reducing power, and anabolism, in which the cell uses energy and reducing power to construct complex molecules and perform other biological functions. Cells were discovered by Robert Hooke in 1665, who named them for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells. Cells emerged on Earth at least 3.5 billion years ago. The study of cells is called cell biology or cellular biology.

scholarly journals The Where, When, and How of Organelle Acidification by the Yeast Vacuolar H+-ATPase

2006 ◽  
Vol 70 (1) ◽  
pp. 177-191 ◽  
Author(s):  
Patricia M. Kane
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Current Knowledge ◽  
Structure And Function ◽  
Regulatory Mechanisms ◽  
Eukaryotic Cells ◽  
Higher Eukaryotes ◽  
Specific Regulation ◽  
And Function ◽  
Acidic Organelles ◽  
The Relationship

SUMMARY All eukaryotic cells contain multiple acidic organelles, and V-ATPases are central players in organelle acidification. Not only is the structure of V-ATPases highly conserved among eukaryotes, but there are also many regulatory mechanisms that are similar between fungi and higher eukaryotes. These mechanisms allow cells both to regulate the pHs of different compartments and to respond to changing extracellular conditions. The Saccharomyces cerevisiae V-ATPase has emerged as an important model for V-ATPase structure and function in all eukaryotic cells. This review discusses current knowledge of the structure, function, and regulation of the V-ATPase in S. cerevisiae and also examines the relationship between biosynthesis and transport of V-ATPase and compartment-specific regulation of acidification.

scholarly journals Molecular characterization of CHAD domains as inorganic polyphosphate binding modules

2019 ◽  
Author(s):  
Laura Lorenzo-Orts ◽  
Ulrich Hohmann ◽  
Jinsheng Zhu ◽  
Michael Hothorn
Keyword(s):  
Mutational Analysis ◽  
Dissociation Constants ◽  
Complex Structure ◽  
High Specificity ◽  
Eukaryotic Cells ◽  
Inorganic Polyphosphates ◽  
Inorganic Polyphosphate ◽  
Surface Patches ◽  
C Terminus

AbstractInorganic polyphosphates (polyPs) are long polymers of orthophosphate units (Pi), linked by energy-rich phosphoanhydride bonds. Conserved histidine α-helical (CHAD) domains of unknown biochemical function are often located at the C-terminus of polyP-metabolizing triphosphate tunnel metalloenzymes (TTMs), or can be found as stand-alone proteins in bacterial operons harboring polyP kinases or phosphatases. Here we report that bacterial, archaeal and eukaryotic CHAD domains are specific polyP binding modules. Crystal structures reveal that CHAD domains are formed by two four-helix bundles, giving rise to a central cavity surrounded by two conserved basic surface patches. Different CHAD domains bind polyPs with dissociation constants ranging from the nano-to mid-micromolar range, but not DNA or other Pi-containing ligands. A 2.1 Å CHAD - polyP complex structure reveals the phosphate polymer binding across a central pore and along the two basic patches. Mutational analysis of CHAD – polyP interface residues validates the complex structure and reveals that CHAD domains evolved to bind long-chain polyPs. The presence of a CHAD domain in the polyPase ygiF enhances its enzymatic activity. In plants, CHAD domains bind polyP in vivo and localize to the nucleus and nucleolus, suggesting that plants harbor polyP stores in these compartments. We propose that CHAD domains may be used to engineer the properties of polyP-metabolizing enzymes and to specifically localize polyP stores in eukaryotic cells and tissues.SignificanceA domain of unknown function termed CHAD, present in all kingdoms of life, is characterized as a specific inorganic polyphosphate binding domain. The small size of the domain and its high specificity for inorganic polyphosphates suggest that it could be used as a tool to locate inorganic polyphosphate stores in pro- and eukaryotic cells and tissues.

scholarly journals Modulation of Innate Immune Toxicity by Silver Nanoparticle Exposure and the Preventive Effects of Pterostilbene

2021 ◽  
Vol 22 (5) ◽  
pp. 2536
Author(s):  
Rong-Jane Chen ◽  
Chiao-Ching Huang ◽  
Rosita Pranata ◽  
Yu-Hsuan Lee ◽  
Yu-Ying Chen ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Good Alternative ◽  
Innate Immune ◽  
Toxic Effects ◽  
Transgenic Zebrafish ◽  
Zebrafish Model ◽  
Cytokines And Chemokines ◽  
Living Organisms ◽  
And Function ◽  
Immune Toxicity

Silver nanoparticles pose a potential risk to ecosystems and living organisms due to their widespread use in various fields and subsequent gradual release into the environment. Only a few studies have investigated the effects of silver nanoparticles (AgNPs) toxicity on immunological functions. Furthermore, these toxic effects have not been fully explored. Recent studies have indicated that zebrafish are considered a good alternative model for testing toxicity and for evaluating immunological toxicity. Therefore, the purpose of this study was to investigate the toxicity effects of AgNPs on innate immunity using a zebrafish model and to investigate whether the natural compound pterostilbene (PTE) could provide protection against AgNPs-induced immunotoxicity. Wild type and neutrophil- and macrophage-transgenic zebrafish lines were used in the experiments. The results indicated that the exposure to AgNPs induced toxic effects including death, malformation and the innate immune toxicity of zebrafish. In addition, AgNPs affect the number and function of neutrophils and macrophages. The expression of immune-related cytokines and chemokines was also affected. Notably, the addition of PTE could activate immune cells and promote their accumulation in injured areas in zebrafish, thereby reducing the damage caused by AgNPs. In conclusion, AgNPs may induce innate immune toxicity and PTE could ameliorate this toxicity.

scholarly journals Brain Long Noncoding RNAs: Multitask Regulators of Neuronal Differentiation and Function

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3951
Author(s):  
Sarva Keihani ◽  
Verena Kluever ◽  
Eugenio F. Fornasiero
Keyword(s):  
Neuronal Differentiation ◽  
Neuronal Excitability ◽  
Noncoding Rnas ◽  
Long Noncoding Rnas ◽  
Regulatory Mechanisms ◽  
Control Robustness ◽  
Living Organisms ◽  
And Function ◽  
Regulatory Functions ◽  
Neuronal Physiology

The extraordinary cellular diversity and the complex connections established within different cells types render the nervous system of vertebrates one of the most sophisticated tissues found in living organisms. Such complexity is ensured by numerous regulatory mechanisms that provide tight spatiotemporal control, robustness and reliability. While the unusual abundance of long noncoding RNAs (lncRNAs) in nervous tissues was traditionally puzzling, it is becoming clear that these molecules have genuine regulatory functions in the brain and they are essential for neuronal physiology. The canonical view of RNA as predominantly a ‘coding molecule’ has been largely surpassed, together with the conception that lncRNAs only represent ‘waste material’ produced by cells as a side effect of pervasive transcription. Here we review a growing body of evidence showing that lncRNAs play key roles in several regulatory mechanisms of neurons and other brain cells. In particular, neuronal lncRNAs are crucial for orchestrating neurogenesis, for tuning neuronal differentiation and for the exact calibration of neuronal excitability. Moreover, their diversity and the association to neurodegenerative diseases render them particularly interesting as putative biomarkers for brain disease. Overall, we foresee that in the future a more systematic scrutiny of lncRNA functions will be instrumental for an exhaustive understanding of neuronal pathophysiology.

Form and function of eukaryotic unstable non-coding RNAs

2012 ◽  
Vol 40 (4) ◽  
pp. 836-841 ◽  
Author(s):  
Jonathan Houseley
Keyword(s):  
Unknown Function ◽  
Budding Yeast ◽  
Rna Degradation ◽  
Present Review ◽  
Form And Function ◽  
Non Coding Rna ◽  
Non Coding Rnas ◽  
Higher Eukaryotes ◽  
And Function

Unstable non-coding RNAs are produced from thousands of loci in all studied eukaryotes (and also prokaryotes), but remain of largely unknown function. The present review summarizes the mechanisms of eukaryotic non-coding RNA degradation and highlights recent findings regarding function. The focus is primarily on budding yeast where the bulk of this research has been performed, but includes results from higher eukaryotes where available.

scholarly journals Ubiquitous organic molecule-based free-standing nanowires with ultra-high aspect ratios

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Koshi Kamiya ◽  
Kazuto Kayama ◽  
Masaki Nobuoka ◽  
Shugo Sakaguchi ◽  
Tsuneaki Sakurai ◽  
...  
Keyword(s):  
Critical Dimension ◽  
High Energy ◽  
Free Standing ◽  
Dry Process ◽  
3D Space ◽  
Aspect Ratios ◽  
Structural Functions ◽  
Planar Structures ◽  
Organic Nanostructures ◽  
Straight Trajectory

AbstractThe critical dimension of semiconductor devices is approaching the single-nm regime, and a variety of practical devices of this scale are targeted for production. Planar structures of nano-devices are still the center of fabrication techniques, which limit further integration of devices into a chip. Extension into 3D space is a promising strategy for future; however, the surface interaction in 3D nanospace make it hard to integrate nanostructures with ultrahigh aspect ratios. Here we report a unique technique using high-energy charged particles to produce free-standing 1D organic nanostructures with high aspect ratios over 100 and controlled number density. Along the straight trajectory of particles penetrating the films of various sublimable organic molecules, 1D nanowires were formed with approximately 10~15 nm thickness and controlled length. An all-dry process was developed to isolate the nanowires, and planar or coaxial heterojunction structures were built into the nanowires. Electrical and structural functions of the developed standing nanowire arrays were investigated, demonstrating the potential of the present ultrathin organic nanowire systems.

scholarly journals Balancing Bees and Livestock: Pastoralist Knowledge, Perceptions and Implications for Pollinator Conservation in Rangelands, Northern Tanzania

2021 ◽  
Vol 14 ◽  
pp. 194008292110281
Author(s):  
Faith Thomas Mpondo ◽  
Patrick A. Ndakidemi ◽  
Anna C. Treydte
Keyword(s):  
Cropping Systems ◽  
Community Outreach ◽  
Habitat Destruction ◽  
Livelihood Diversification ◽  
Group Discussions ◽  
Northern Tanzania ◽  
Insect Pollinators ◽  
Living Organisms ◽  
And Function ◽  
Rangeland Health

Insect pollinators provide numerous ecosystem services that support other living organisms. While pollinators play a large role in cropping systems, little is known about their presence and function in rangeland ecosystems, which have recently become fragmented and overexploited at an extraordinary rate. We assessed local Maasai knowledge on insect pollinators and how pollinators affect livelihood diversification in Simanjiro rangelands, Tanzania. Through questionnaires, key informant interviews, focus group discussions, and field observations, we found varied insect knowledge among Maasai herders. Lasioglossum of sub genus Ipomalictus and Syriphidae were the least commonly recognized pollinators as only 24%, and 7% of participants could identify them, respectively. Responses varied significantly between men and women (F = 7.397, p = .007). Commiphora africana, Acacia mellifera and Albizia anthelmintica were noted as most important bee forage plants while observations showed Aspilia mossambicensis, Justicia debile and Acacia tortilis. Most (77%) of Maasai herders showed limited ability to link pollinators and rangeland wellbeing. Beekeeping contributed to livelihood diversification for 61% of respondents, with women participating more frequently than men (χ2 = 46.962, p = .0001). Beekeeping was positively influenced by education level ( R = .421, p < .0001) and occupation ( R = .194, p = .009). Pollinator declines were attributed to climate change (47%), agriculture (37%), and habitat destruction (8%). We conclude that Maasai have limited knowledge of common pollinator groups and their roles. Community outreach and training should bridge the knowledge gap in pastoralist communities to fully realize pollinator benefits and highlight the importance of rangeland health.

Developments and controversies in maxillofacial trauma: Repair of facial injuries

2010 ◽  
Vol 1 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Michael Perry
Keyword(s):  
Functional Disability ◽  
Motor Vehicle ◽  
Sports Injuries ◽  
High Energy ◽  
Aetiological Factor ◽  
Rigid Fixation ◽  
Form And Function ◽  
Improved Outcomes ◽  
The Uk ◽  
And Function

Craniofacial trauma remains a common health problem throughout many areas of the UK. Although the ‘combination of alcohol and testosterone’ is often regarded as a major aetiological factor, a significant number of injuries are not related to either. Motor vehicle collisions and equine-related sports injuries in particular can result in devastating injuries to the skull and face and are frequently seen.Over the last few decades, management has moved away from closed methods to open exposure, anatomical reduction and internal ‘rigid’ fixation of facial fractures, with significant improvements in outcomes. Nevertheless, current management of ‘high energy’ or complex fractures can still result in residual functional disability and cosmetic deformity.Today’s challenge is to restore patients back to their pre-injury form and function, consistently, but this is not always possible. Greater understanding and a number of developments have significantly improved outcomes, although controversy still exists in some areas. Some of these will be discussed.

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