The permeabilized SecY protein-translocation channel can serve as a nonspecific sugar transporter

2018 ◽  
Author(s):  
Sen Mei ◽  
Chong Xie ◽  
Hao Mi ◽  
Chuang Xue ◽  
Qiang Guo ◽  
...  
Keyword(s):  
Carbon Catabolite Repression ◽  
Protein Translocation ◽  
Competitive Inhibition ◽  
Wide Spectrum ◽  
Decisive Role ◽  
Initial Step ◽  
Facilitated Diffusion ◽  
Sugar Transporters ◽  
Carbohydrate Catabolism ◽  
Specific Sugar

AbstractAs the initial step in carbohydrate catabolism in cells, the substrate-specific transporters via active transport and facilitated diffusion play a decisive role in passage of sugars through the plasma membrane into the cytoplasm. The SecY complex (SecYEG) in bacteria forms a membrane channel responsible for protein translocation. This work demonstrates that weakening the sealability of the SecY channel allowed free diffusion of sugars, including glucose, fructose, mannose, xylose, arabinose, and lactose, into the engineered cells, facilitating its rapid growth on a wide spectrum of monosaccharides and bypassing/reducing stereospecificity, transport saturation, competitive inhibition, and carbon catabolite repression (CCR), which are usually encountered with the specific sugar transporters. The SecY channel is structurally conserved in prokaryotes, thus it may be engineered to serve as a unique and universal transporter for bacteria to passage sugars as demonstrated inEscherichia coliandClostridium acetobutylicum.

scholarly journals COVID-19 Vaccine Hesitancy Worldwide: A Concise Systematic Review of Vaccine Acceptance Rates

Vaccines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 160
Author(s):  
Malik Sallam
Keyword(s):  
Middle East ◽  
General Public ◽  
Healthcare Workers ◽  
Decisive Role ◽  
Initial Step ◽  
Sub Saharan Africa ◽  
Vaccine Hesitancy ◽  
Vaccine Acceptance ◽  
Republic Of The Congo ◽  
Acceptance Rates

Utility of vaccine campaigns to control coronavirus 2019 disease (COVID-19) is not merely dependent on vaccine efficacy and safety. Vaccine acceptance among the general public and healthcare workers appears to have a decisive role in the successful control of the pandemic. The aim of this review was to provide an up-to-date assessment of COVID-19 vaccination acceptance rates worldwide. A systematic search of the peer-reviewed English survey literature indexed in PubMed was done on 25 December 2020. Results from 31 peer-reviewed published studies met the inclusion criteria and formed the basis for the final COVID-19 vaccine acceptance estimates. Survey studies on COVID-19 vaccine acceptance rates were found from 33 different countries. Among adults representing the general public, the highest COVID-19 vaccine acceptance rates were found in Ecuador (97.0%), Malaysia (94.3%), Indonesia (93.3%) and China (91.3%). However, the lowest COVID-19 vaccine acceptance rates were found in Kuwait (23.6%), Jordan (28.4%), Italy (53.7), Russia (54.9%), Poland (56.3%), US (56.9%), and France (58.9%). Only eight surveys among healthcare workers (doctors and nurses) were found, with vaccine acceptance rates ranging from 27.7% in the Democratic Republic of the Congo to 78.1% in Israel. In the majority of survey studies among the general public stratified per country (29/47, 62%), the acceptance of COVID-19 vaccination showed a level of ≥70%. Low rates of COVID-19 vaccine acceptance were reported in the Middle East, Russia, Africa and several European countries. This could represent a major problem in the global efforts to control the current COVID-19 pandemic. More studies are recommended to address the scope of COVID-19 vaccine hesitancy. Such studies are particularly needed in the Middle East and North Africa, Sub-Saharan Africa, Eastern Europe, Central Asia, Middle and South America. Addressing the scope of COVID-19 vaccine hesitancy in various countries is recommended as an initial step for building trust in COVID-19 vaccination efforts.

scholarly journals Real-time observation of signal recognition particle binding to actively translating ribosomes

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Thomas R Noriega ◽  
Jin Chen ◽  
Peter Walter ◽  
Joseph D Puglisi
Keyword(s):  
Real Time ◽  
Single Molecule ◽  
Protein Translocation ◽  
Signal Sequence ◽  
Signal Recognition Particle ◽  
Initial Step ◽  
Signal Recognition ◽  
Fluorescence Measurements ◽  
Nascent Chain ◽  
Time Observation

The signal recognition particle (SRP) directs translating ribosome-nascent chain complexes (RNCs) that display a signal sequence to protein translocation channels in target membranes. All previous work on the initial step of the targeting reaction, when SRP binds to RNCs, used stalled and non-translating RNCs. This meant that an important dimension of the co-translational process remained unstudied. We apply single-molecule fluorescence measurements to observe directly and in real-time E. coli SRP binding to actively translating RNCs. We show at physiologically relevant SRP concentrations that SRP-RNC association and dissociation rates depend on nascent chain length and the exposure of a functional signal sequence outside the ribosome. Our results resolve a long-standing question: how can a limited, sub-stoichiometric pool of cellular SRP effectively distinguish RNCs displaying a signal sequence from those that are not? The answer is strikingly simple: as originally proposed, SRP only stably engages translating RNCs exposing a functional signal sequence.

Metabolite movement across the schistosome surface

2012 ◽  
Vol 86 (2) ◽  
pp. 141-147 ◽  
Author(s):  
A. Da'dara ◽  
G. Krautz-Peterson ◽  
Z. Faghiri ◽  
P.J. Skelly
Keyword(s):  
Amino Acids ◽  
Glucose Transporter ◽  
Basal Membrane ◽  
Facilitated Diffusion ◽  
Comprehensive Understanding ◽  
Transporter Proteins ◽  
Sugar Transporters ◽  
Transporter Protein ◽  
Parasite Survival

AbstractIntravascular schistosome parasites are covered by an unusual double lipid bilayer. Nutrients, such as glucose and amino acids, as well as other metabolites, are known to be transported across this surface via specific transporter proteins. For instance, the glucose transporter protein SGTP4 is found in the host-interactive tegumental membranes. A second glucose transporter, SGTP1, localizes to the tegumental basal membrane (and internal tissues). Following expression inXenopusoocytes, SGTP1 and SGTP4 both function as facilitated-diffusion sugar transporters. Suppressing the expression of SGTP1 and SGTP4 in juvenile schistosomes using RNA interference (RNAi) impairs the parasite's ability to import glucose and severely decreases worm viability. Amino acids can also be imported into schistosomes across their surface and an amino acid transporter (SPRM1lc) has been localized in the parasite surface membranes (as well as internally). InXenopusoocytes, SPRM1lc can import the basic amino acids arginine, lysine and histidine as well as leucine, phenylalanine, methionine and glutamine. To function, this protein requires the assistance of a heavy-chain partner (SPRM1hc) which acts as a chaperone. Water is transported across the tegument of schistosomes via the aquaporin protein SmAQP. Suppressing SmAQP gene expression makes the parasites less able to osmoregulate and decreases their viability. In addition, SmAQP-suppressed adult parasites have been shown to be impaired in their ability to excrete lactate. Analysis of tegumental transporter proteins, as described in this report, is designed to generate a comprehensive understanding of the role of such proteins in promoting parasite survival by controlling the movement of metabolites into and out of the worms.

scholarly journals Neuroprotective Polyphenols: A Modulatory Action on Neurotransmitter Pathways

2020 ◽  
Vol 18 (5) ◽  
pp. 431-445 ◽  
Author(s):  
Elzbieta Rebas ◽  
Jowita Rzajew ◽  
Tomasz Radzik ◽  
Ludmila Zylinska
Keyword(s):  
Nervous System ◽  
Positive Impact ◽  
Wide Spectrum ◽  
Neurological Diseases ◽  
Decisive Role ◽  
Biologically Active ◽  
Plant Polyphenols ◽  
Synthetic Drugs ◽  
The Central Nervous System ◽  
Neuroprotective Actions

Background: Balance in neurotransmission is essential for the proper functioning of the nervous system and even a small, but prolonged disturbance, can induce the negative feedback mechanisms leading to various neuropathologies. Neurodegenerative and mood disorders such as Alzheimer’s, Parkinson’s or affective disorders are increasing medical and social problems. Among the wide spectrum of potentially destructive events, oxidative stress and disrupted metabolism of some neurotransmitters such as acetylcholine, GABA, glutamate, serotonin or dopamine appear to play a decisive role. Biologically active plant polyphenols have been shown to exert a positive impact on the function of the central nervous system by modulation of metabolism and the action of some neurotransmitters. Methods: Based on published research, the pharmacological activities of some naturally occurring polyphenols have been reviewed, with a focus on their potential therapeutic importance in the regulation of neurotransmitter systems. Results: Phytochemicals can be classified into several groups and most of them possess anticancer, antioxidative, anti-inflammatory and neuroprotective properties. They can also modulate the metabolism or action of some neurotransmitters and/or their receptors. Based on these properties, phytochemicals have been used in traditional medicine for ages, although it was focused mainly on treating symptoms. However, growing evidence indicates that polyphenols may also prevent or slow neurological diseases. Conclusion: Phytochemicals seem to be less toxic than synthetic drugs and they can be a safer alternative for currently used preparations, which exert adverse side effects. The neuroprotective actions of some plant polyphenols in the regulation of neurotransmitters metabolism, functioning of neurotransmitters receptors and antioxidative defense have potential therapeutic applications in various neurodegenerative disorders.

The osmotolerant fructophilic yeast Zygosaccharomyces rouxii employs two plasma-membrane fructose uptake systems belonging to a new family of yeast sugar transporters

Microbiology ◽  
2011 ◽  
Vol 157 (2) ◽  
pp. 601-608 ◽  
Author(s):  
Maria José Leandro ◽  
Hana Sychrová ◽  
Catarina Prista ◽  
Maria C. Loureiro-Dias
Keyword(s):  
Plasma Membrane ◽  
Diffusion Mechanism ◽  
Sugar Transport ◽  
High Capacity ◽  
Transport Systems ◽  
Facilitated Diffusion ◽  
Sugar Transporters ◽  
Zygosaccharomyces Rouxii ◽  
New Family ◽  
Spoilage Yeasts

Owing to its high resistance to weak-acid preservatives and extreme osmotolerance, Zygosaccharomyces rouxii is one of the main spoilage yeasts of sweet foods and beverages. In contrast with Saccharomyces cerevisiae, Z. rouxii is a fructophilic yeast; it consumes fructose faster than glucose. So far, to our knowledge, no specific Z. rouxii proteins responsible for this fructophilic behaviour have been characterized. We have identified two genes encoding putative fructose transporters in the Z. rouxii CBS 732 genome. Heterologous expression of these two Z. rouxii ORFs in a S. cerevisiae strain lacking its own hexose transporters (hxt-null) and subsequent kinetic analysis of sugar transport showed that both proteins are functionally expressed at the plasma membrane: ZrFfz1 is a high-capacity fructose-specific facilitator (K m∼400 mM and V max∼13 mmol h−1 g−1) and ZrFfz2 is a facilitator transporting glucose and fructose with similar capacity and affinity (K m∼200 mM and V max∼4 mmol h−1 g−1). These two proteins together with the Zygosaccharomyces bailii Ffz1 fructose-specific transporter belong to a new family of sugar transport systems mediating the uptake of hexoses via the facilitated diffusion mechanism, and are more homologous to drug/H+ antiporters (regarding their primary protein structure) than to other yeast sugar transporters of the Sugar Porter family.

A specific sugar transport mechanism in smooth muscle and its regulation

1976 ◽  
Vol 54 (3) ◽  
pp. 254-261 ◽  
Author(s):  
I. Bihler ◽  
P. C. Sawh ◽  
J. Elbrink
Keyword(s):  
Smooth Muscle ◽  
Sugar Transport ◽  
Facilitated Diffusion ◽  
Inhibitory Effects ◽  
Rat Urinary Bladder ◽  
Specificity And Sensitivity ◽  
Rate Limiting ◽  
Specific Sugar

The membrane transport of 3-O-methyl-D-glucose was studied in vitro in a smooth muscle, the detrusor of rat urinary bladder. Transport occurred by facilitated diffusion and showed the same chemical specificity and sensitivity to specific inhibitors as skeletal and cardiac muscle but its insulin sensitivity was smaller. Transport was increased by agents inhibiting the Na+ pump and was decreased by agents which increased Na+ and K+ gradients by apparently stimulating the Na+ pump. In accord with a rate limiting role of transport in glucose utilization, similar stimulating and inhibitory effects were seen when CO2 production from [14C]glucose was measured.

Study on Mechanism of Anaerobic Sludge Granulation in UASB Reactors

1993 ◽  
Vol 28 (7) ◽  
pp. 171-178 ◽  
Author(s):  
Chen Jian ◽  
Lun Shi-yi
Keyword(s):  
Kinetic Data ◽  
Fermentation Broth ◽  
Wide Spectrum ◽  
Decisive Role ◽  
Uasb Reactor ◽  
Second Step ◽  
Anaerobic Sludge ◽  
Nucleus Formation ◽  
Uasb Reactors ◽  
Sludge Granulation

Sludge granulation in a 15 m3 UASB reactor, with alcoholic stillage from ethanol fermentation broth as influent, has been studied. Based on kinetic data as well as both scanning and transmitting scope observation and identification, a hypothesis for the mechanism of anaerobic sludge granulation is suggested. The first step of granulation is the formation of nuclei. The bacteria involved in the nucleus formation are mainly M. sarcina and M. thrix. The acetic acid concentration and the “selection pressure” play a decisive role for determining the nucleus formation. A wide spectrum of other bacteria, which the methanogens must syntrophically grow with, also play a very important role during the second step, that is the process of a nucleus growing into a granule.

scholarly journals A Comprehensive Tutorial onIn VitroCharacterization of New Photosensitizers for Photodynamic Antitumor Therapy and Photodynamic Inactivation of Microorganisms

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Tobias Kiesslich ◽  
Anita Gollmer ◽  
Tim Maisch ◽  
Mark Berneburg ◽  
Kristjan Plaetzer
Keyword(s):  
Photodynamic Therapy ◽  
Cell Biology ◽  
Wide Spectrum ◽  
Photophysical Properties ◽  
Intracellular Localization ◽  
Initial Step ◽  
Photodynamic Inactivation ◽  
Comprehensive Collection ◽  
Light Protection

In vitroresearch performed on eukaryotic or prokaryotic cell cultures usually represents the initial step for characterization of a novel photosensitizer (PS) intended for application in photodynamic therapy (PDT) of cancer or photodynamic inactivation (PDI) of microorganisms. Although many experimental steps of PS testing make use of the wide spectrum of methods readily employed in cell biology, special aspects of working with photoactive substances, such as the autofluorescence of the PS molecule or the requirement of light protection, need to be considered when performingin vitroexperiments in PDT/PDI. This tutorial represents a comprehensive collection of operative instructions, by which, based on photochemical and photophysical properties of a PS, its uptake into cells, the intracellular localization and photodynamic action in both tumor cells and microorganisms novel photoactive molecules may be characterized for their suitability for PDT/PDI. Furthermore, it shall stimulate the efforts to expand the convincing benefits of photodynamic therapy and photodynamic inactivation within both established and new fields of applications and motivate scientists of all disciplines to get involved in photodynamic research.

scholarly journals CONCEPT OF SOPHA (INFLAMMATION): A CRITICAL STUDY

2020 ◽  
Vol 8 (8) ◽  
pp. 15-23
Author(s):  
Ashok Panda ◽  
Rabinarayan Tripathy
Keyword(s):  
Wide Spectrum ◽  
Modern Science ◽  
Disease Process ◽  
Decisive Role ◽  
Modern Medicine ◽  
Critical Study ◽  
Graduate Curriculum ◽  
Classification Of Diseases ◽  
Back Ground

Back ground- Inflammation has a decisive role in pathological classification of diseases in modern medicine and well-known phenomenon of infectious diseases and Non communicable disorders (NCD) also. Ayurveda emphasised the doshic involvement in pathophysiology of diseases process   and the phenomenon of Sopha is undetermined in diagnosis and treatment. Objective- A literature survey from Ayurveda classical texts was undertaken to understand the role of Sopha in disease process.    Methods- The enumerations of Sopha in Bruhatrayee, Madhav nidana & Bhela Samhita are critically studied to find out its etiology, types, pathogenesis and line of treatment.  Enumeration- Sopha is very fundamental to understand the disease process in Ayurveda.    The normal snigdha-sheet- agneya character of Srotas get disturbed by the Vidahi & Abhisandhya dravyas, as a result there is a disturbed in the transport mechanism of the affected Srotas. Sopha can be a symptom of any disease and/or an independent disease and may be a complication of other diseases. Sopha can be classified as Antah Sopha & Bahir Sopha. Discussion- The concept of sopha was discussed in terms of pathology and treatment of modern science. Conclusion- Sopha is linked with wide spectrum of Infectious as well as Non communicable disorders (NCD). This study also found out a range of therapies for Sopha driven diseases. It can be recommended to include this concept of Sopha in Ayurveda undergraduate and post graduate curriculum.

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