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Maarten A Mees, Christiane Effenberg, Dietmar Appelhans, Richard Hoogenboom
Carbohydrates are important in signaling, energy storage and metabolism. Depending on their function, carbohydrates can be part of larger structures, such as glycoproteins, glycolipids or other functionalities (glycoside). To this end, polymers can act as carriers of carbohydrates in so-called glycopolymers, which mimic the multivalent carbohydrate functionalities. We chose a biocompatible poly(2-ethyl-2-oxazoline) (PEtOx) as the basis for making glycopolymers. Via the partial hydrolysis of PEtOx, a copolymer of PEtOx and polyethyleneimine (PEI) was obtained; the subsequent reductive amination with the linear forms of glucose and maltose yielded the glycopolymers...
October 21, 2016: Biomacromolecules
R D Astumian
Molecular machines use external energy to drive transport, to do mechanical, osmotic, or electrical work on the environment, and to form structure. In this paper the fundamental difference between the design principles necessary for a molecular machine to use light or external modulation of thermodynamic parameters as an energy source vs. the design principle for using an exergonic chemical reaction as a fuel will be explored. The key difference is that for catalytically-driven motors microscopic reversibility must hold arbitrarily far from equilibrium...
October 21, 2016: Faraday Discussions
Shu Yang, Anne Rosenwald
Macroautophagy, a highly conserved process in eukaryotic cells, is initiated in response to stress, especially nutrient starvation. Macroautophagy helps cells survive by engulfing proteins and organelles into an unusual double-membraned structure called the autophagosome, which then fuses with the lysosome. Upon degradation of the engulfed contents, the building blocks are recycled for synthesis of new macromolecules. Recent work has demonstrated that construction of the autophagosome requires a variety of small GTPases in variations of their normal roles in membrane traffic...
October 20, 2016: Small GTPases
Ho Ting Wong, Vico Chung Lim Chiang, Kup Sze Choi, Alice Yuen Loke
The rapid development of technology has made enormous volumes of data available and achievable anytime and anywhere around the world. Data scientists call this change a data era and have introduced the term "Big Data", which has drawn the attention of nursing scholars. Nevertheless, the concept of Big Data is quite fuzzy and there is no agreement on its definition among researchers of different disciplines. Without a clear consensus on this issue, nursing scholars who are relatively new to the concept may consider Big Data to be merely a dataset of a bigger size...
October 17, 2016: International Journal of Environmental Research and Public Health
Nikolai N Sluchanko, Konstantin E Klementiev, Evgeny A Shirshin, Georgy V Tsoraev, Thomas Friedrich, Eugene G Maksimov
In Cyanobacteria, the Orange Carotenoid Protein (OCP) and Fluorescence Recovery Protein (FRP) are central to the photoprotective mechanism consisting in regulated quenching of phycobilisome (PBs) fluorescence. Due to a transient and flexible nature of the light-activated red quenching form, OCP(R), which is obtained from the stable dark-adapted orange form, OCP(O), by photoconversion, the detailed mechanism of photoprotection remains unclear. Here we demonstrate that our recently described W288A mutant of the Synechocystis OCP (hereinafter called OCP(W288A)) is a fully functional analogue of the OCP(R) form which is capable of constitutive PBs fluorescence quenching in vitro with no need of photoactivation...
October 15, 2016: Biochimica et Biophysica Acta
Casey O Diekman, Amitabha Bose
Circadian oscillators found across a variety of species are subject to periodic external light-dark forcing. Entrainment to light-dark cycles enables the circadian system to align biological functions with appropriate times of day or night. Phase response curves (PRCs) have been used for decades to gain valuable insights into entrainment; however, PRCs may not accurately describe entrainment to photoperiods with substantial amounts of both light and dark due to their reliance on a single limit cycle attractor...
October 17, 2016: Journal of Biological Rhythms
M A Sinetova, D A Los
Systemic analysis of stress transcriptomes of the cyanobacterium Synechocystis revealed that all stress-induced genes can be separated into two groups: one is clustered around heat-shock- and another - around cold-shock inducible genes. Genes for so-called heat shock proteins (HSPs) are induced by various stressors, e.g. heat, salt, hyperosmotic environment, reactive oxygen species (ROS), changes in light intensity and quality, or in the redox potential of the photosynthetic electron transport chain components...
October 18, 2016: Molecular BioSystems
Marika Rai, David Spratt, Paola R Gomez-Pereira, Jay Patel, Sean P Nair
Oral malodour is a common condition which affects a large proportion of the population, resulting in social, emotional and psychological stress. Certain oral bacteria form a coating called a biofilm on the tongue dorsum and degrade organic compounds releasing volatile sulfur compounds that are malodourous. Current chemical treatments for oral malodour such as mouthwashes containing chlorhexidine or essential oils, are not sufficiently effective at reducing the bacterial load on the tongue. One potential alternative to current chemical treatments for oral malodour is the use of light activated antimicrobial agents (LAAAs), which display no toxicity or antimicrobial activity in the dark, but when exposed to light of a specific wavelength produce reactive oxygen species which induce damage to target cells in a process known as photodynamic inactivation...
October 18, 2016: Journal of Breath Research
A Yaba, B Sozen, B Suzen, N Demir
Tanycytes are special ependymal cells located in the ventrolateral wall and floor of the third ventricle having processes extending nuclei that regulate reproductive functions and around of vessels in median eminance. The aquaporins (AQPs) are a family of transmembrane proteins that transport water and glycerol. AQP-7 and -9 are permeable to other small molecules as glycerol and therefore called aquaglyceroporins. In this study, we aimed to show localization of AQP-7 and -9 in epithelial cells of choroid plexus and tanycytes during female mouse estrus cycle...
October 13, 2016: Morphologie: Bulletin de L'Association des Anatomistes
K A Lee, C O'Sullivan, P Daly, J Pears, C Owens, B Timmermann, C Ares, S E Combs, D Indelicato, M Capra
BACKGROUND: Proton therapy (PT) is a radiotherapy treatment modality that uses protons, rather than conventional photons. PT is often used in paediatric oncology due to its reported capability to reduce acute and late adverse treatment effects. As PT is unavailable in Ireland, patients are referred abroad for treatment. AIMS: To: (1) produce a descriptive study of Irish children referred abroad for PT, and (2) discuss the case for PT in general. METHODS: A retrospective review of all children referred for PT before October 2015 was performed...
October 15, 2016: Irish Journal of Medical Science
Qiang Niu, Xu Yang, Shouwan Gao, Pengpeng Chen, Shibing Chan
Localization is crucial for the monitoring applications of cities, such as road monitoring, environment surveillance, vehicle tracking, etc. In urban road sensor networks, sensors are often sparely deployed due to the hardware cost. Under this sparse deployment, sensors cannot communicate with each other via ranging hardware or one-hop connectivity, rendering the existing localization solutions ineffective. To address this issue, this paper proposes a novel Traffic Lights Schedule-based localization algorithm (TLS), which is built on the fact that vehicles move through the intersection with a known traffic light schedule...
October 10, 2016: Sensors
Spyridon Gkoumas, Pablo Villanueva-Perez, Zhentian Wang, Lucia Romano, Matteo Abis, Marco Stampanoni
In X-ray grating interferometry, dark-field contrast arises due to partial extinction of the detected interference fringes. This is also called visibility reduction and is attributed to small-angle scattering from unresolved structures in the imaged object. In recent years, analytical quantitative frameworks of dark-field contrast have been developed for highly diluted monodisperse microsphere suspensions with maximum 6% volume fraction. These frameworks assume that scattering particles are separated by large enough distances, which make any interparticle scattering interference negligible...
October 13, 2016: Scientific Reports
Nambin Yim, Chulhee Choi
Extracellular vesicles (EVs) are natural carriers of biomolecules that play central roles in cell-to-cell communications. Based on this, there have been many attempts to use EVs as therapeutic drug carriers. Various macromolecules, from chemical reagents to nucleic acids, were successfully loaded into EVs; however, loading of proteins with high molecular weight has been huddled with several problems. Purification of recombinant proteins is expensive and time consuming, and easily results in modification of proteins by physical or chemical forces...
October 13, 2016: BMB Reports
Stephanie Höhn, Armin Hallmann
BACKGROUND: The multicellular volvocine alga Pleodorina is intermediate in organismal complexity between its unicellular relative, Chlamydomonas, and its multicellular relative, Volvox, which shows complete division of labor between different cell types. The volvocine green microalgae form a group of genera closely related to the genus Volvox within the order Volvocales (Chlorophyta). Embryos of multicellular volvocine algae consist of a cellular monolayer that, depending on the species, is either bowl-shaped or comprises a sphere...
October 13, 2016: BMC Developmental Biology
Liliana R Cisneros Castillo, Andrei-Dumitru Oancea, Christian Stüllein, Anne Régnier-Vigouroux
Multicellular tumor spheroids (MCTSs) embedded in a matrix are re-emerging as a powerful alternative to monolayer-based cultures. The primary information gained from a three-dimensional model is the invasiveness of treatment-exposed MCTSs through the acquisition of light microscopy images. The amount and complexity of the acquired data and the bias arisen by their manual analysis are disadvantages calling for an automated, high-throughput analysis. We present a universal algorithm we developed with the scope of being robust enough to handle images of various qualities and various invasion profiles...
October 12, 2016: Scientific Reports
Yi Li, Chi Zhang, Danmeng Shuai, Saraschandra Naraginti, Dawei Wang, Wenlong Zhang
The challenge to achieve effective water disinfection of pathogens, especially viruses, with minimized harmful disinfection byproducts calls for a cost-effective and environmentally benign technology. Here, polymeric graphitic carbon nitride (g-C3N4), as a metal-free robust photocatalyst, was explored for the first time for its ability to inactivate viruses under visible light irradiation. MS2 with an initial concentration of 1 × 10(8) PFU/mL was completely inactivated by g-C3N4 with a loading of 150 mg/L under visible light irradiation of 360 min...
October 5, 2016: Water Research
Sihuai Sun, Xiaobing Yang, Yao Wang, Xihui Shen
Proteins are the elementary machinery of life, and their functions are carried out mostly by molecular interactions. Among those interactions, protein-protein interactions (PPIs) are the most important as they participate in or mediate all essential biological processes. However, many common methods for PPI investigations are slightly unreliable and suffer from various limitations, especially in the studies of dynamic PPIs. To solve this problem, a method called Bioluminescence Resonance Energy Transfer (BRET) was developed about seventeen years ago...
October 11, 2016: International Journal of Molecular Sciences
Dariusz M Niedzwiedzki, Christopher Neil Hunter, Robert E Blankenship
Carotenoids are a class of natural pigments present in all phototrophic organisms, mainly in their light-harvesting proteins in which they play roles of accessory light absorbers and photoprotectors. Extensive time-resolved spectroscopic studies of these pigments have revealed unexpectedly complex photophysical properties, particularly for carotenoids in light-harvesting LH2 complexes from purple bacteria. An ambiguous, optically forbidden electronic excited state designated as S* has been postulated to be involved in carotenoid excitation relaxation and in an alternative carotenoid-to-bacteriochlorophyll energy transfer pathway, as well as being a precursor of the carotenoid triplet state...
October 11, 2016: Journal of Physical Chemistry. B
Valentina Rapozzi, Greta Varchi, Emilia Della Pietra, Claudia Ferroni, Luigi E Xodo
Photodynamic therapy (PDT) has drawn considerable attention for its efficacy against certain types of cancers. It shows however limits in the case of deep cancers, favoring tumor recurrence under suboptimal conditions. More insight into the molecular mechanisms of PDT-induced cytotoxicity and cytoprotection is essential to extend and strengthen this therapeutic modality. As PDT induces iNOS/NO in both tumor and microenvironment, we examined the role of nitric oxide (NO) in cytotoxicity and cytoprotection. Our findings show that NO mediates its cellular effects by acting on the NF-κB/YY1/RKIP loop, which controls cell growth and apoptosis...
October 11, 2016: Investigational New Drugs
Pavel Y Apel, Valery V Bashevoy, Irina V Blonskaya, Nikolay E Lizunov, Oleg L Orelovitch, Christina Trautmann
The method of producing single track-etched conical nanopores has received considerable attention and found many applications in diverse fields such as biosensing, nanofluidics, information processing and others. The performance of an asymmetric nanopore is largely determined by its geometry, especially by the size and shape of its tip. In this paper we reconstruct the profiles of so-called conical pores fabricated by asymmetric chemical etching of ion tracks in polymer foil. Conductometric measurements during etching and field emission scanning electron microscopy examinations of the resulting pores were employed in order to determine the pore geometry...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
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