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https://www.readbyqxmd.com/read/28230975/tuning-of-recombinant-protein-expression-in-escherichia-coli-by-manipulating-transcription-translation-initiation-rates-and-incorporation-of-non-canonical-amino-acids
#1
Orr Schlesinger, Yonatan Chemla, Mathias Heltberg, Eden Ozer, Ryan Marshall, Vincent Noireaux, Mogens Hogh Jensen, Lital Alfonta
Protein synthesis in cells has been thoroughly investigated and characterized over the past 60 years. However, some fundamental issues remain unresolved, including the reasons for genetic code redundancy and codon bias. In this study, we changed the kinetics of the E. coli transcription and translation processes by mutating the promoter and ribosome binding domains and by using genetic code expansion. The results expose a counterintuitive phenomenon, whereby an increase in the initiation rates of transcription and translation lead to a decrease in protein expression...
February 23, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28230380/effects-of-6-hydroxyceramides-on-the-thermotropic-phase-behavior-and-permeability-of-model-skin-lipid-membranes
#2
Andrej Kovacik, Michaela Silarova, Petra Pullmannová, Jaroslav Maixner, Katerina Vavrova
Ceramides (Cer) based on 6-hydroxysphingosine are important components of the human skin barrier, the stratum corneum. Although diminished concentrations of 6-hydroxyCer have been detected in skin diseases such as atopic dermatitis, our knowledge of these unusual sphingolipids, which have only been found in the skin, is limited. In this work, we investigate the biophysical behavior of N-lignoceroyl 6-hydroxysphingosine (Cer NH) in multilamellar lipid membranes composed of Cer/free fatty acids (C16-C24)/cholesterol/cholesteryl sulfate...
February 23, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28229459/differential-serotonergic-modulation-across-the-main-and-accessory-olfactory-bulbs
#3
Zhenbo Huang, Nicolas Thiebaud, Debra Ann Fadool
Mitral cells (MCs) contained in the main (MOB) and accessory (AOB) olfactory bulb have distinct intrinsic membrane properties but a comparison of the extent of neuromodulation across the two systems is not well explored. Herein, we investigated a widely-distributed CNS modulator, serotonin (5-HT), for its ability to modulate the biophysical properties of MCs across the MOB and AOB, using an in vitro, brain slice approach in postnatal 15-30 day mice. In the MOB, 5-HT elicited three types of responses in 93% of 180 cells tested...
February 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28229022/opportunities-drive-the-global-distribution-of-protected-areas
#4
Germán Baldi, Marcos Texeira, Osvaldo A Martin, H Ricardo Grau, Esteban G Jobbágy
BACKGROUND: Protected areas, regarded today as a cornerstone of nature conservation, result from an array of multiple motivations and opportunities. We explored at global and regional levels the current distribution of protected areas along biophysical, human, and biological gradients, and assessed to what extent protection has pursued (i) a balanced representation of biophysical environments, (ii) a set of preferred conditions (biological, spiritual, economic, or geopolitical), or (iii) existing opportunities for conservation regardless of any representation or preference criteria...
2017: PeerJ
https://www.readbyqxmd.com/read/28228754/proofreading-of-peptide-mhc-complexes-through-dynamic-multivalent-interactions
#5
REVIEW
Christoph Thomas, Robert Tampé
The adaptive immune system is able to detect and destroy cells that are malignantly transformed or infected by intracellular pathogens. Specific immune responses against these cells are elicited by antigenic peptides that are presented on major histocompatibility complex class I (MHC I) molecules and recognized by cytotoxic T lymphocytes at the cell surface. Since these MHC I-presented peptides are generated in the cytosol by proteasomal protein degradation, they can be metaphorically described as a window providing immune cells with insights into the state of the cellular proteome...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28228527/activation-mechanism-of-the-g-protein-coupled-sweet-receptor-heterodimer-with-sweeteners-and-allosteric-agonists
#6
Soo-Kyung Kim, Yalu Chen, Ravinder Abrol, William A Goddard, Brian Guthrie
The sweet taste in humans is mediated by the TAS1R2/TAS1R3 G protein-coupled receptor (GPCR), which belongs to the class C family that also includes the metabotropic glutamate and γ-aminobutyric acid receptors. We report here the predicted 3D structure of the full-length TAS1R2/TAS1R3 heterodimer, including the Venus Flytrap Domains (VFDs) [in the closed-open (co) active conformation], the cysteine-rich domains (CRDs), and the transmembrane domains (TMDs) at the TM56/TM56 interface. We observe that binding of agonists to VFD2 of TAS1R2 leads to major conformational changes to form a TM6/TM6 interface between TMDs of TAS1R2 and TAS1R3, which is consistent with the activation process observed biophysically on the metabotropic glutamate receptor 2 homodimer...
February 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28228073/principal-physicochemical-methods-used-to-characterize-dendrimer-molecule-complexes-used-as-genetic-therapy-agents-nanovaccines-or-drug-carriers
#7
Rodríguez Fonseca Rolando Alberto, Rodrigues Joao, Muñoz-Fernández María de Los Angeles, Martínez Muñoz Alberto, Fragoso Vázquez Manuel Jonathan, Correa Basurto José
Nanomedicine is the application of nanotechnology to medicine. This field is related to the study of nanodevices and nanomaterials applied to various medical uses, such as in improving the pharmacological properties of different molecules. Dendrimers are synthetic nanoparticles whose physicochemical properties vary according to their chemical structure. These molecules have been extensively investigated as drug nanocarriers to improve drug solubility and as sustained-release systems. New therapies such as gene therapy and the development of nanovaccines can be improved by the use of dendrimers...
February 20, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28227835/multi-chip-dataflow-architecture-for-massive-scale-biophysically-accurate-neuron-simulation
#8
Jaco Hofmann, Amir Zjajo, Carlo Galuzzi, Rene van Leuken, Jaco Hofmann, Amir Zjajo, Carlo Galuzzi, Rene van Leuken, Carlo Galuzzi, Rene Van Leuken, Jaco Hofmann, Amir Zjajo
State-of-the-art neuron simulators are capable of simulating at most few tens/hundreds of neurons in real-time due to the exponential growth in the communication costs with the number of simulated neurons. In this paper, we present a novel, reconfigurable, multi-chip system architecture based on localized communication, which effectively reduces the communication cost to a linear growth. The system is very flexible and it allows to tune, at run-time, various parameters, e.g. the intracellular concentration of chemical compounds, the interconnection scheme between the neurons...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226616/a-real-time-hybrid-neuron-network-for-highly-parallel-cognitive-systems
#9
Gerrit Jan Christiaanse, Amir Zjajo, Carlo Galuzzi, Rene van Leuken, Gerrit Jan Christiaanse, Amir Zjajo, Carlo Galuzzi, Rene van Leuken, Carlo Galuzzi, Gerrit Jan Christiaanse, Rene van Leuken, Amir Zjajo
For comprehensive understanding of how neurons communicate with each other, new tools need to be developed that can accurately mimic the behaviour of such neurons and neuron networks under `real-time' constraints. In this paper, we propose an easily customisable, highly pipelined, neuron network design, which executes optimally scheduled floating-point operations for maximal amount of biophysically plausible neurons per FPGA family type. To reduce the required amount of resources without adverse effect on the calculation latency, a single exponent instance is used for multiple neuron calculation operations...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226461/role-of-cytosolic-calcium-diffusion-in-cardiac-purkinje-cells
#10
Bijay Limbu, Kushal Shah, Makarand Deo, Bijay Limbu, Kushal Shah, Makarand Deo, Bijay Limbu, Makar Deo, Kushal Shah
The Cardiac Purkinje cells (PCs) exhibit distinct calcium (Ca(2)+) homeostasis than that in ventricular myocytes (VMs). Due to lack of t-tubules in PCs, the Ca(2)+ ions entering the cell have to diffuse through the cytoplasm to reach the sarcoplasmic reticulum (SR) before triggering Ca(2)+-induced-Ca(2)+-release (CICR). In recent experimental studies PCs have been shown to be more susceptible to action potential (AP) abnormalities than the VMs, however the exact mechanisms are poorly understood. In this study, we utilize morphologically realistic detailed biophysical mathematical model of a murine PC to systematically examine the role intracellular Ca(2)+ diffusion in the APs of PCs...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226216/overcoming-immune-dysregulation-with-immunoengineered-nanobiomaterials
#11
Evan A Scott, Nicholas B Karabin, Punn Augsornworawat
The immune system is governed by an immensely complex network of cells and both intracellular and extracellular molecular factors. It must respond to an ever-growing number of biochemical and biophysical inputs by eliciting appropriate and specific responses in order to maintain homeostasis. But as with any complex system, a plethora of false positives and false negatives can occur to generate dysregulated responses. Dysregulated immune responses are essential components of diverse inflammation-driven pathologies, including cancer, heart disease, and autoimmune disorders...
February 9, 2017: Annual Review of Biomedical Engineering
https://www.readbyqxmd.com/read/28225803/bacterial-expression-correct-membrane-targeting-and-functional-folding-of-the-hiv-1-membrane-protein-vpu-using-a-periplasmic-signal-peptide
#12
Arpan Deb, William A Johnson, Alexander P Kline, Boston J Scott, Lydia R Meador, Dustin Srinivas, Jose M Martin-Garcia, Katerina Dörner, Chad R Borges, Rajeev Misra, Brenda G Hogue, Petra Fromme, Tsafrir S Mor
Viral protein U (Vpu) is a type-III integral membrane protein encoded by Human Immunodeficiency Virus-1 (HIV- 1). It is expressed in infected host cells and plays several roles in viral progeny escape from infected cells, including down-regulation of CD4 receptors. But key structure/function questions remain regarding the mechanisms by which the Vpu protein contributes to HIV-1 pathogenesis. Here we describe expression of Vpu in bacteria, its purification and characterization. We report the successful expression of PelB-Vpu in Escherichia coli using the leader peptide pectate lyase B (PelB) from Erwinia carotovora...
2017: PloS One
https://www.readbyqxmd.com/read/28225654/germicidal-efficacy-and-mammalian-skin-safety-of-222-nm-uv-light
#13
Manuela Buonanno, Brian Ponnaiya, David Welch, Milda Stanislauskas, Gerhard Randers-Pehrson, Lubomir Smilenov, Franklin D Lowy, David M Owens, David J Brenner
We have previously shown that 207-nm ultraviolet (UV) light has similar antimicrobial properties as typical germicidal UV light (254 nm), but without inducing mammalian skin damage. The biophysical rationale is based on the limited penetration distance of 207-nm light in biological samples (e.g. stratum corneum) compared with that of 254-nm light. Here we extended our previous studies to 222-nm light and tested the hypothesis that there exists a narrow wavelength window in the far-UVC region, from around 200-222 nm, which is significantly harmful to bacteria, but without damaging cells in tissues...
February 22, 2017: Radiation Research
https://www.readbyqxmd.com/read/28225152/topical-phenytoin-for-treating-pressure-ulcers
#14
REVIEW
Xiang Yong Hao, Hong Ling Li, He Su, Hui Cai, Tian Kang Guo, Ruifeng Liu, Lei Jiang, Yan Fei Shen
BACKGROUND: Pressure ulcers are common in clinical practice and pose a significant health problem worldwide. Apart from causing suffering to patients, they also result in longer hospital stays and increase the cost of health care. A variety of methods are used for treating pressure ulcers, including pressure relief, patient repositioning, biophysical strategies, nutritional supplementation, debridement, topical negative pressure, and local treatments including dressings, ointments and creams such as bacitracin, silver sulphadiazine, neomycin, and phenytoin...
February 22, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28223913/neuromorphic-implementation-of-attractor-dynamics-in-a-two-variable-winner-take-all-circuit-with-nmdars-a-simulation-study
#15
Hongzhi You, Da-Hui Wang
Neural networks configured with winner-take-all (WTA) competition and N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic dynamics are endowed with various dynamic characteristics of attractors underlying many cognitive functions. This paper presents a novel method for neuromorphic implementation of a two-variable WTA circuit with NMDARs aimed at implementing decision-making, working memory and hysteresis in visual perceptions. The method proposed is a dynamical system approach of circuit synthesis based on a biophysically plausible WTA model...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28223358/structural-and-biochemical-analysis-of-escherichia-coli-obge-a-central-regulator-of-bacterial-persistence
#16
Sotirios Gkekas, Ranjan Kumar Singh, Alexander V Shkumatov, Joris Messens, Maarten Fauvart, Natalie Verstraeten, Jan Michiels, Wim Versées
The Obg protein family belongs to the TRAFAC (translation factor) class of P-loop GTPases and is conserved from bacteria to eukaryotes. Essential roles in many different cellular processes have been suggested for the Obg protein from Escherichia coli (ObgE), and we recently showed that it is a central regulator of bacterial persistence. Here, we report the first crystal structure of ObgE at 1.85 Å resolution in the GDP-bound state, showing the characteristic N-terminal domain and a central G domain that are common to all Obg proteins...
February 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28223224/transient-receptor-potential-canonical-type-3-channels-interactions-role-and-relevance-a-vascular-focus
#17
REVIEW
T Hilton Grayson, Timothy V Murphy, Shaun L Sandow
Transient receptor potential canonical type 3 channels (TRPC3) are expressed in neural, cardiac, respiratory and vascular tissues, with both similarities and differences between human and animal models for the same cell types. In common with all members of the six subfamilies of TRP channels, TRPC3 are non-voltage gated, non-selective cation channels that are mainly permeated by Ca(2+), and have distinct molecular, biophysical, anatomical and functional properties. TRP channels are present in excitable and non-excitable cells where they sense and respond to a wide variety of physical and chemical stimuli...
February 13, 2017: Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/28223017/novel-bcl2-inhibitor-disarib-induces-apoptosis-by-disruption-of-bcl2-bak-interaction
#18
Supriya V Vartak, Divyaanka Iyer, T R Santhoshkumar, Sheetal Sharma, Archita Mishra, Gunaseelan Goldsmith, Mrinal Srivastava, Shikha Srivastava, Subhas S Karki, Avadhesha Surolia, Bibha Choudhary, Sathees C Raghavan
Apoptosis is a highly regulated pathway of programmed cell death relying on the fine balance between pro and antiapoptotic binding partners. Overexpression of the antiapoptotic protein BCL2 in several cancers makes it an ideal target for chemotherapy, with minimum side effects. In one of our previous studies, we designed, synthesized and characterized Disarib, a BCL2-specific small molecule inhibitor. Interestingly, Disarib showed a novel mode of BCL2 inhibition, by predominantly binding to its BH1 domain, as compared to the BH3-specific action of other known BCL2 inhibitors...
February 18, 2017: Biochemical Pharmacology
https://www.readbyqxmd.com/read/28222010/optical-tweezers-studies-of-transcription-by-eukaryotic-rna-polymerases
#19
Ana Lisica, Stephan W Grill
Transcription is the first step in the expression of genetic information and it is carried out by large macromolecular enzymes called RNA polymerases. Transcription has been studied for many years and with a myriad of experimental techniques, ranging from bulk studies to high-resolution transcript sequencing. In this review, we emphasise the advantages of using single-molecule techniques, particularly optical tweezers, to study transcription dynamics. We give an overview of the latest results in the single-molecule transcription field, focusing on transcription by eukaryotic RNA polymerases...
February 21, 2017: Biomolecular Concepts
https://www.readbyqxmd.com/read/28221776/the-horizon-of-materiobiology-a-perspective-on-material-guided-cell-behaviors-and-tissue-engineering
#20
Yulin Li, Yin Xiao, Changsheng Liu
Although the biological functions of cell and tissue can be regulated by biochemical factors (e.g., growth factors, hormones), the biophysical effects of materials on the regulation of biological activity are receiving more attention. In this Review, we systematically summarize the recent progress on how biomaterials with controllable properties (e.g., compositional/degradable dynamics, mechanical properties, 2D topography, and 3D geometry) can regulate cell behaviors (e.g., cell adhesion, spreading, proliferation, cell alignment, and the differentiation or self-maintenance of stem cells) and tissue/organ functions...
February 21, 2017: Chemical Reviews
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