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Sunil Nath
As the chief energy source of eukaryotic cells, it is important to determine the thermodynamic efficiency of ATP synthesis in oxidative phosphorylation (OX PHOS). Previous estimates of the thermodynamic efficiency of this vital process have ranged from Lehninger's original back-of-the-envelope calculation of 38% to the often quoted value of 55-60% in current textbooks of biochemistry, to high values of 90% from recent information theoretic considerations, and reports of realizations of close to ideal 100% efficiencies by single molecule experiments...
October 15, 2016: Biophysical Chemistry
Minoo Heidari Kani, Eng-Cheng Chan, Roger C Young, Trent Butler, Roger Smith, Jonathan W Paul
Research insights into uterine function and the mechanisms of labour have been hindered by the lack of suitable animal and cellular models. The use of traditional culturing methods limits the exploration of complex uterine functions, such as cell interactions, connectivity and contractile behaviour, as it fails to mimic the three-dimensional (3D) nature of uterine cell interactions in vivo. Animal models are an option, however, use of these models is constrained by ethical considerations as well as translational limitations to humans...
October 21, 2016: Annals of Biomedical Engineering
Jamie L Burgess, R Alan Burgess, Yalemi Morales, Jenna M Bouvang, Sean J Johnson, Nicholas E Dickenson
Like many Gram-negative pathogens, Shigella rely on a complex type three secretion system (T3SS) to inject effector proteins into host cells, take over host functions, and ultimately establish infection. Despite these critical roles, the energetics and regulatory mechanisms controlling the T3SS and pathogen virulence remain largely unclear. In this study, we present a series of high-resolution crystal structures of Spa47 and use the structures to model an activated Spa47 oligomer, finding that ATP hydrolysis may be supported by specific sidechain contributions from adjacent protomers within the complex...
October 21, 2016: Journal of Biological Chemistry
Thomas D Loreng, Elizabeth F Smith
The motile cilium is a complex organelle that is typically comprised of a 9+2 microtubule skeleton; nine doublet microtubules surrounding a pair of central singlet microtubules. Like the doublet microtubules, the central microtubules form a scaffold for the assembly of protein complexes forming an intricate network of interconnected projections. The central microtubules and associated structures are collectively referred to as the central apparatus (CA). Studies using a variety of experimental approaches and model organisms have led to the discovery of a number of highly conserved protein complexes, unprecedented high-resolution views of projection structure, and new insights into regulation of dynein-driven microtubule sliding...
October 21, 2016: Cold Spring Harbor Perspectives in Biology
Hongyu Sun, Jiajia Tang, Yongchao Mou, Jing Zhou, Linlin Qu, Kayla Duval, Zhu Huang, Ning Lin, Ruiwu Dai, Chengxiao Liang, Zi Chen, Lijun Tang, Fuzhou Tian
: Carbon nanotube (CNT)-based hydrogels have been shown to support cardiomyocyte growth and function. However, their role in cellular integrity among cardiomyocytes has not been studied in detail and the mechanisms underlying this process remain unclear. Here, single walled CNTs incorporated into gelatin with methacrylate anhydride (CNT/GelMA) hydrogels were utilized to construct cardiac tissues, which enhanced cardiomyocyte adhesion and maturation. Furthermore, through the use of immunohistochemical staining, transmission electron microscopy and intracellular calcium transient measurement, the incorporation of CNTs into the scaffolds was observed to markedly enhance the assembly and formation in the cardiac constructs...
October 18, 2016: Acta Biomaterialia
William R Pitchers, Savvas J Constantinou, Mauricio Losilla, Jason R Gallant
Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21(st) century biological questions...
October 18, 2016: Journal of Physiology, Paris
Matilde M Vaghi, Petra E Vértes, Manfred G Kitzbichler, Annemieke M Apergis-Schoute, Febe E van der Flier, Naomi A Fineberg, Akeem Sule, Rashid Zaman, Valerie Voon, Prantik Kundu, Edward T Bullmore, Trevor W Robbins
BACKGROUND: A recent hypothesis has suggested that core deficits in goal-directed behavior in obsessive-compulsive disorder (OCD) are caused by impaired frontostriatal function. We tested this hypothesis in OCD patients and control subjects by relating measures of goal-directed planning and cognitive flexibility to underlying resting-state functional connectivity. METHODS: Multiecho resting-state acquisition, combined with micromovement correction by blood oxygen level-dependent sensitive independent component analysis, was used to obtain in vivo measures of functional connectivity in 44 OCD patients and 43 healthy comparison subjects...
August 11, 2016: Biological Psychiatry
Jamel Meslamani, Steven G Smith, Roberto Sanchez, Ming-Ming Zhou
Bromodomains are conserved structural modules responsible for recognizing acetylated-lysine residues on histone tails and other transcription-associated proteins, such as transcription factors and co-factors. Owing to their important functions in the regulation of ordered gene transcription in chromatin, bromodomains of the BET family proteins have recently been shown as druggable targets for a wide array of human diseases, including cancer and inflammation. Here we review the structural and functional features of the bromodomains and their small-molecule inhibitors...
March 2016: Drug Discovery Today. Technologies
Alex Hall, Tracy Finch, Niina Kolehmainen, Deborah James
BACKGROUND: Implementing good-quality health and social care requires empowerment of staff members within organizations delivering care. Video Interaction Guidance (VIG) is an intervention using positive video feedback to empower staff through reflection on practice. This qualitative study explored the implementation of VIG within an autism care organization in England, from the perspective of staff members undergoing training to deliver VIG. METHODS: Semi-structured interviews were conducted with a purposive sample of 7 participants working within the organization (5 staff undergoing training to deliver VIG; 2 senior managers influencing co-ordination of training)...
October 21, 2016: BMC Health Services Research
Allan M Showalter, Brian D Keppler, Xiao Liu, Jens Lichtenberg, Lonnie R Welch
BACKGROUND: Hydroxyproline-rich glycoproteins (HRGPs) constitute a plant cell wall protein superfamily that functions in diverse aspects of growth and development. This superfamily contains three members: the highly glycosylated arabinogalactan-proteins (AGPs), the moderately glycosylated extensins (EXTs), and the lightly glycosylated proline-rich proteins (PRPs). Chimeric and hybrid HRGPs, however, also exist. A bioinformatics approach is employed here to identify and classify AGPs, EXTs, PRPs, chimeric HRGPs, and hybrid HRGPs from the proteins predicted by the completed genome sequence of poplar (Populus trichocarpa)...
October 21, 2016: BMC Plant Biology
Hongwu Wang, Kun Li, Xiaojiao Hu, Zhifang Liu, Yujin Wu, Changling Huang
BACKGROUND: Plant digestibility of silage maize (Zea mays L.) has a large influence on nutrition intake for animal feeding. Improving forage quality will enhance the utilization efficiency and feeding value of forage maize. Dissecting the genetic basis of forage quality will improve our understanding of the complex nature of cell wall biosynthesis and degradation, which is also helpful for breeding good quality silage maize. RESULTS: Acid detergent fiber (ADF), neutral detergent fiber (NDF) and in vitro dry matter digestibility (IVDMD) of stalk were evaluated in a diverse maize population, which is comprised of 368 inbred lines and planted across seven environments...
October 21, 2016: BMC Plant Biology
Na Li, Yunhuan Yan, Angke Zhang, Jiming Gao, Chong Zhang, Xue Wang, Gaopeng Hou, Gaiping Zhang, Jinbu Jia, En-Min Zhou, Shuqi Xiao
Many viruses encode microRNAs (miRNAs) that are small non-coding single-stranded RNAs which play critical roles in virus-host interactions. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically impactful viruses in the swine industry. The present study sought to determine whether PRRSV encodes miRNAs that could regulate PRRSV replication. Four viral small RNAs (vsRNAs) were mapped to the stem-loop structures in the ORF1a, ORF1b and GP2a regions of the PRRSV genome by bioinformatics prediction and experimental verification...
October 17, 2016: Oncotarget
Anirban Basu, Gopinatha Suresh Kumar
Interaction of proflavine with hemoglobin (Hgb) was studied employing spectroscopy, calorimetry, and atomic force microscopy. The equilibrium constant was found to be of the order 10(4)M(-1). The quenching of Hgb fluorescence by proflavine was due to the complex formation. Calculation of the molecular distance (r) between the donor (β-Trp37 of Hgb) and acceptor (proflavine) suggested that energy can be efficiently transferred from the β-Trp37 residue at the α1β2 interface of the protein to the dye. Proflavine induced significant secondary structural changes in Hgb...
October 12, 2016: Journal of Photochemistry and Photobiology. B, Biology
Peter S Shen, Xiaoyong Yang, Paul G DeCaen, Xiaowen Liu, David Bulkley, David E Clapham, Erhu Cao
The Polycystic Kidney Disease 2 (Pkd2) gene is mutated in autosomal dominant polycystic kidney disease (ADPKD), one of the most common human monogenic disorders. Here, we present the cryo-EM structure of PKD2 in lipid bilayers at 3.0 Å resolution, which establishes PKD2 as a homotetrameric ion channel and provides insight into potential mechanisms for its activation. The PKD2 voltage-sensor domain retains two of four gating charges commonly found in those of voltage-gated ion channels. The PKD2 ion permeation pathway is constricted at the selectivity filter and near the cytoplasmic end of S6, suggesting that two gates regulate ion conduction...
October 20, 2016: Cell
Tian Hua, Kiran Vemuri, Mengchen Pu, Lu Qu, Gye Won Han, Yiran Wu, Suwen Zhao, Wenqing Shui, Shanshan Li, Anisha Korde, Robert B Laprairie, Edward L Stahl, Jo-Hao Ho, Nikolai Zvonok, Han Zhou, Irina Kufareva, Beili Wu, Qiang Zhao, Michael A Hanson, Laura M Bohn, Alexandros Makriyannis, Raymond C Stevens, Zhi-Jie Liu
Cannabinoid receptor 1 (CB1) is the principal target of Δ(9)-tetrahydrocannabinol (THC), a psychoactive chemical from Cannabis sativa with a wide range of therapeutic applications and a long history of recreational use. CB1 is activated by endocannabinoids and is a promising therapeutic target for pain management, inflammation, obesity, and substance abuse disorders. Here, we present the 2.8 Å crystal structure of human CB1 in complex with AM6538, a stabilizing antagonist, synthesized and characterized for this structural study...
October 20, 2016: Cell
Jiachao Zhang, Qisong Hu, Chuanbiao Xu, Sixin Liu, Congfa Li
Pepper pericarp microbiota plays an important role in the pepper peeling process for the production of white pepper. We collected pepper samples at different peeling time points from Hainan Province, China, and used a metagenomic approach to identify changes in the pericarp microbiota based on functional gene analysis. UniFrac distance-based principal coordinates analysis revealed significant changes in the pericarp microbiota structure during peeling, which were attributed to increases in bacteria from the genera Selenomonas and Prevotella...
2016: PloS One
Majid Jafari, Faramarz Mehrnejad
Changes in the tertiary structure of proteins and the resultant fibrillary aggregation could result in fatal heredity diseases, such as lysozyme systemic amyloidosis. Human lysozyme is a globular protein with antimicrobial properties with tendencies to fibrillate and hence is known as a fibril-forming protein. Therefore, its behavior under different ambient conditions is of great importance. In this study, we conducted two 500000 ps molecular dynamics (MD) simulations of human lysozyme in sodium dodecyl sulfate (SDS) at two ambient temperatures...
2016: PloS One
Nasim Bahrami, Masoumeh Sibmar, William M Bukowski, AbouAli Vedadhir, Bianca Panarello
AIM: The aim of this study was to identify factors that promote and impede other-sex (OS) friendships in adolescent girls. METHODS: A qualitative study conducted with 20 adolescent girls recruited in public places in Tehran, Iran. Information was collected through semi-structured interviews and coded via the conventional qualitative content analysis approach. RESULTS: Four factors were identified that appeared to promote entry into OS friendships...
October 21, 2016: International Journal of Adolescent Medicine and Health
Radwan Elzein, Chun-Min Chang, Inna Ponomareva, Wen-Yang Gao, Shengqian Ma, Rudy Schlaf
Metal-organic frameworks (MOFs) deposited from solution have the potential to form 2-dimensional supramolecular thin films suitable for molecular electronic applications. However, the main challenges lie in achieving selective attachment to the substrate surface, and the integration of organic conductive ligands into the MOF structure to achieve conductivity. The presented results demonstrate that photoemission spectroscopy combined with preparation in a system-attached glovebox can be used to characterize the electronic structure of such systems...
October 21, 2016: ACS Applied Materials & Interfaces
Allison B Norvil, Christopher J Petell, Lama Abdullah Alabdi, Lanchen Wu, Sandra Rossie, Humaira Gowher
The catalytic domains of the de novo DNA methyltransferases, Dnmt3a-C and Dnmt3b-C are highly homologous. However their unique biochemical properties could potentially contribute to differences in the substrate preferences or biological functions of these enzymes. Dnmt3a-C forms tetramers through interactions at the dimer interface, which also promote multimerization on DNA and cooperativity. Similar to processive enzymes, cooperativity allows Dnmt3a-C to methylate multiple sites on the same DNA molecule, however it is unclear whether Dnmt3b-C methylates DNA by cooperative or processive mechanism...
October 21, 2016: Biochemistry
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