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Adaptive switch

Niels Bradshaw, Vladimir M Levdikov, Christina M Zimanyi, Rachelle Gaudet, Anthony J Wilkinson, Richard Losick
PP2C phosphatases control biological processes including stress responses, development, and cell division in all kingdoms of life. Diverse regulatory domains adapt PP2C phosphatases to specific functions, but how these domains control phosphatase activity was unknown. We present structures representing active and inactive states of the PP2C phosphatase SpoIIE from Bacillus subtilis. Based on structural analyses and genetic and biochemical experiments, we identify an α-helical switch that shifts a carbonyl oxygen into the active site to coordinate a metal cofactor...
May 20, 2017: ELife
Yun-Juan Bao, Yang Li, Zhong Liang, Garima Agrahari, Shaun W Lee, Victoria A Ploplis, Francis J Castellino
The strains serotyped as M71 from group A Streptococcus are common causes of pharyngeal and skin diseases worldwide. Here we characterize the genome of a unique non-invasive M71 human isolate, NS53. The genome does not contain structural rearrangements or large-scale gene gains/losses, but encodes a full set of non-truncated known virulence factors, thus providing an ideal reference for comparative studies. However, the NS53 genome showed incongruent phenotypic implications from distinct genotypic markers. NS53 is characterized as an emm pattern D and FCT (fibronectin-collagen-T-antigen) type-3 strain, typical of skin tropic strains, but is phylogenetically close to emm pattern E strains with preference for both skin and pharyngeal infections...
May 17, 2017: Pathogens and Disease
Amélie Vézina, Cyndia Charfi, Alain Zgheib, Borhane Annabi
Switches in sphingolipid metabolism have recently been associated with oncogenic transformation, and a role for the low-density lipoprotein receptor-related protein 1 (LRP1) in sphingosine-1-phosphate (S1P) proangiogenic signaling inferred. S1P signaling crosstalk with LRP1 in brain microvascular endothelial cells (HBMEC) is however unclear. Transient in vitro siLRP1 gene silencing was compared to stable shLRP1 knockdown. We observed decreased expression of CCAAT/enhancer binding protein β (C/EBPβ), a transcription factor for which multiple binding sites are found within the promoter sequences of all five S1P receptor members, upon stable but not transient LRP1 repression...
May 17, 2017: Molecular Neurobiology
Kenneth T Bogen
Kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid 2-like factor 2-related factor 2 (Nrf2), and the antioxidant response element (ARE) are interacting components of a master regulatory signaling pathway that coordinates redox homeostasis, cytoprotective responses, and shifts in stem cell state. This study reexamined detailed dose-response (DR) data reported for in vitro Nrf2-ARE activation in human hepatoblastoma HepG2 cell lines containing either a ARE-bla or ARE-luc reporter at 12 different concentrations of each of 15 chemicals...
April 2017: Dose-response: a Publication of International Hormesis Society
Amir A Al-Khami, Paulo C Rodriguez, Augusto C Ochoa
The past decade has seen a significant interest in investigating the intracellular metabolism of cells of the immune system. This has increased the realization that immune cells endure metabolic reprogramming upon responding to pathogen-derived or inflammatory signals. More importantly, not only does this metabolic switch provide for the bioenergetic and biosynthetic demands but also it, in a highly specific manner, determines the cellular fate and function. In this review, we discuss the metabolic aspects that regulate the differentiation and function of myeloid cells, pivotal for both innate and adaptive immunity...
May 17, 2017: Journal of Leukocyte Biology
Er-Hu Chen, Qiu-Li Hou, Dan-Dan Wei, Hong-Bo Jiang, Jin-Jun Wang
In this study, we investigated the effects of dietary restriction (DR) and variable diets on phenotypes and gene expression in oriental fruit fly, Bactrocera dorsalis (Hendel), one of the most economically important pests in the family Tephritidae around the world. As expected, we found that DR altered the B. dorsalis phenotypes by significantly increasing stress resistance and lifespan, but reduced egg production when compared with the control diet. The results suggested a trade-off between reproduction versus somatic maintenance (stress resistance) and lifespan in B...
May 16, 2017: Scientific Reports
Nicole S Webster, Thorsten B H Reusch
On contemplating the adaptive capacity of reef organisms to a rapidly changing environment, the microbiome offers significant and greatly unrecognised potential. Microbial symbionts contribute to the physiology, development, immunity and behaviour of their hosts, and can respond very rapidly to changing environmental conditions, providing a powerful mechanism for acclimatisation and also possibly rapid evolution of coral reef holobionts. Environmentally acquired fluctuations in the microbiome can have significant functional consequences for the holobiont phenotype upon which selection can act...
May 16, 2017: ISME Journal
Jian-Hua Zhang, Jia-Jun Xia, Jonathan M Garibaldi, Petros P Groumpos, Ru-Bin Wang
BACKGROUND AND OBJECTIVE: In human-machine (HM) hybrid control systems, human operator and machine cooperate to achieve the control objectives. To enhance the overall HM system performance, the discrete manual control task-load by the operator must be dynamically allocated in accordance with continuous-time fluctuation of psychophysiological functional status of the operator, so-called operator functional state (OFS). The behavior of the HM system is hybrid in nature due to the co-existence of discrete task-load (control) variable and continuous operator performance (system output) variable...
June 2017: Computer Methods and Programs in Biomedicine
Jonathan Herrmann, Fatemeh Jabbarpour, Paul G Bargar, John F Nomellini, Po-Nan Li, Thomas J Lane, Thomas M Weiss, John Smit, Lucy Shapiro, Soichi Wakatsuki
Surface layers (S-layers) are paracrystalline, proteinaceous structures found in most archaea and many bacteria. Often the outermost cell envelope component, S-layers serve diverse functions including aiding pathogenicity and protecting against predators. We report that the S-layer of Caulobacter crescentus exhibits calcium-mediated structural plasticity, switching irreversibly between an amorphous aggregate state and the crystalline state. This finding invalidates the common assumption that S-layers serve only as static wall-like structures...
May 9, 2017: Biophysical Journal
Tung-Hung Su, Chun-Jen Liu
Nucleos(t)ide analogues (NUCs) and interferon have been used for several decades to treat chronic hepatitis B; however, the therapeutic response remains unsatisfactory. Although NUC therapy exhibits potent on-treatment viral suppression, frequent off-therapy virological relapses suggest an indefinite treatment course. Interferon modulates the innate and adaptive antiviral immune responses and thus increases the chance of viral eradication. Interferon therapy has the advantage of a finite duration, absence of drug resistance, and durable posttreatment responses...
May 12, 2017: Gut and Liver
Jun Xiao, Run Jin, Doris Wagner
Plant development is predominantly postembryonic and tuned in to respond to environmental cues. All living plant cells can be triggered to de-differentiate, assume different cell identities, or form a new organism. This developmental plasticity is thought to be an adaptation to the sessile lifestyle of plants. Recent discoveries have advanced our understanding of the orchestration of plant developmental switches by transcriptional master regulators, chromatin state changes, and hormone response pathways. Here, we review these recent advances with emphasis on the earliest stages of plant development and on the switch from pluripotency to differentiation in different plant organ systems...
May 10, 2017: Genome Biology
Dong-Hun Kang, Jaechan Park
Intravenous recombinant tissue plasminogen activator had been the only approved treatment for acute ischemic stroke since its approval in 1995. However, the restrictive time window, numerous contraindications, and its low recanalization rate were all limitations of this modality. Under those circumstances, endovascular stroke therapy went through a great evolution during the past two decades of intravenous thrombolysis. The results of the 2013 randomized trials for endovascular stroke therapy were neutral, although they were limited by insufficient imaging screening at enrollment, early-generation devices with less efficacy, and treatment delays...
May 2017: Journal of Korean Neurosurgical Society
Sankar Prasad Rath, Pritam Mondal
An adaptable cyclic porphyrin dimer with highly flexible linkers has been utilized as an artificial molecular container, which can efficiently encapsulate various aromatic guests (TCNQ/C60/C70) through strong π-π interaction by adjusting its cavity size and conformation. Also, the planar aromatic guest (TCNQ) can be easily exchanged by the larger aromatic guests (C60/C70) selectively. During the guest exchange process, the two porphyrin rings switch their relative orientation according to the size and shape of the guests...
May 9, 2017: Chemistry, An Asian Journal
Gary Thomas, Joseph E Aslan, Laurel Thomas, Pushkar Shinde, Ujwal Shinde, Thomas Simmen
Vertebrate proteins that fulfill multiple and seemingly disparate functions are increasingly recognized as vital solutions to maintaining homeostasis in the face of the complex cell and tissue physiology of higher metazoans. However, the molecular adaptations that underpin this increased functionality remain elusive. In this Commentary, we review the PACS proteins - which first appeared in lower metazoans as protein traffic modulators and evolved in vertebrates to integrate cytoplasmic protein traffic and interorganellar communication with nuclear gene expression - as examples of protein adaptation 'caught in the act'...
May 5, 2017: Journal of Cell Science
Melissa B McPeak, Dima Youssef, Danielle A Williams, Christopher L Pritchett, Zhi Q Yao, Charles E McCall, Mohamed El Gazzar
Sepsis inflammation accelerates myeloid cell generation to compensate for rapid mobilization of the myeloid progenitors from bone marrow. This inflammation-driven myelopoiesis, however, generates myeloid progenitors with immunosuppressive functions that are unable to differentiate into mature, innate immune cells. The myeloid-derived suppressor cells (MDSCs) expand markedly in the later phases of sepsis, suppress both innate and adaptive immunity, and thus, elevate mortality. Using a murine model with myeloid-restricted deletion of the C/EBPβ transcription factor, we show that sepsis-induced generation of MDSCs depends on C/EBPβ...
May 5, 2017: Journal of Leukocyte Biology
Chaojie Li, Xinghuo Yu, Tingwen Huang, Xing He
The resource allocation problem is studied and reformulated by a distributed interior point method via a θ-logarithmic barrier. By the facilitation of the graph Laplacian, a fully distributed continuous-time multiagent system is developed for solving the problem. Specifically, to avoid high singularity of the θ-logarithmic barrier at boundary, an adaptive parameter switching strategy is introduced into this dynamical multiagent system. The convergence rate of the distributed algorithm is obtained. Moreover, a novel distributed primal-dual dynamical multiagent system is designed in a smart grid scenario to seek the saddle point of dynamical economic dispatch, which coincides with the optimal solution...
May 2, 2017: IEEE Transactions on Neural Networks and Learning Systems
Gülistan Koçer, Jeroen Ter Schiphorst, Matthew Hendrikx, Hailu G Kassa, Philippe Leclère, Albertus P H J Schenning, Pascal Jonkheijm
Extracellular microenvironment is highly dynamic where spatiotemporal regulation of cell-instructive cues such as matrix topography tightly regulates cellular behavior. Recapitulating dynamic changes in stimuli-responsive materials has become an important strategy in regenerative medicine to generate biomaterials which closely mimic the natural microenvironment. Here, light responsive liquid crystal polymer networks are used for their adaptive and programmable nature to form hybrid surfaces presenting micrometer scale topographical cues and changes in nanoscale roughness at the same time to direct cell migration...
May 5, 2017: Advanced Materials
Maria Schindler, Mareike Pendzialek, Katarzyna Joanna Grybel, Tom Seeling, Jacqueline Gürke, Bernd Fischer, Anne Navarrete Santos
STUDY QUESTION: How does a maternal diabetic hyperadiponectineamia affect signal transduction and lipid metabolism in rabbit preimplantation blastocysts? SUMMARY ANSWER: In a diabetic pregnancy increased levels of adiponectin led to a switch in embryonic metabolism towards a fatty acid-dependent energy metabolism, mainly affecting genes that are responsible for fatty acid uptake and turnover. WHAT IS KNOWN ALREADY: Although studies in cell culture experiments have shown that adiponectin is able to regulate lipid metabolism via 5'-AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor α (PPARα), data on the effects of adiponectin on embryonic lipid metabolism are not available...
May 4, 2017: Human Reproduction
V Sladek, J Kóňa, H Tokiwa
Golgi α-mannosidase II (GM) is a pharmaceutical target for the design of inhibitors with anticancer activity. The known potent GM inhibitors undergo complex interactions with Zn(2+) ions and the active-site amino acids, many of which contain ionisable functional groups. Herein, the physical insight into the ligandreceptor interactions has been provided based on energy decomposition techniques: SAPT (symmetry adapted perturbation theory) and FMO-PIEDA (fragment molecular orbital-pair interaction energy decomposition analysis) for a large GM active-site cluster...
May 21, 2017: Physical Chemistry Chemical Physics: PCCP
Sean D Connell, Milena Fernandes, Owen W Burnell, Zoë A Doubleday, Kingsley J Griffin, Andrew D Irving, Jonathan Y S Leung, Samuel Owen, Bayden D Russell, Laura J Falkenberg
While the public's value of 'healthy' environments is renown, the science and management of ecosystem health has not been as simple. Ecological systems can be dynamic and unpredictable, with shifts from one ecosystem state to another often considered 'surprising'. This unpredictability is often thought to be due to ecological thresholds, where small cumulative increases in an environmental stressor drives a much greater consequence than would be predicted from linear effects, suggesting an unforeseen tipping point is crossed...
May 2, 2017: Conservation Biology: the Journal of the Society for Conservation Biology
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