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Lani U Gleason, Luke P Miller, Jacob R Winnikoff, George N Somero, Paul H Yancey, Dylan Bratz, W Wesley Dowd
The ability of animals to cope with environmental stress depends - in part - on past experience, yet knowledge of the factors influencing an individual's physiology in nature remains underdeveloped. We used an individual monitoring system to record body temperature and valve gaping behavior of rocky intertidal zone mussels (Mytilus californianus). Thirty individuals were selected from two mussel beds (wave-exposed and wave-protected) that differ in thermal regime. Instrumented mussels were deployed at two intertidal heights (near the lower and upper edges of the mussel zone) and in a continuously submerged tidepool...
November 15, 2017: Journal of Experimental Biology
Aifen Zhou, Rebecca Lau, Richard Baran, Jincai Ma, Frederick von Netzer, Weiling Shi, Drew Gorman-Lewis, Megan L Kempher, Zhili He, Yujia Qin, Zhou Shi, Grant M Zane, Liyou Wu, Benjamin P Bowen, Trent R Northen, Kristina L Hillesland, David A Stahl, Judy D Wall, Adam P Arkin, Jizhong Zhou
Rapid genetic and phenotypic adaptation of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough to salt stress was observed during experimental evolution. In order to identify key metabolites important for salt tolerance, a clone, ES10-5, which was isolated from population ES10 and allowed to experimentally evolve under salt stress for 5,000 generations, was analyzed and compared to clone ES9-11, which was isolated from population ES9 and had evolved under the same conditions for 1,200 generations...
November 14, 2017: MBio
Gulam Rabbani
Nature has selected osmolytes to protect intracellular macromolecules against denaturing stress conditions. These molecules are accumulated in the intracellular environment at considerably high concentrations. In general, osmolytes are known to stabilize proteins. Osmolytes are small naturally occurring compound that are utilized as chemical chaperones by changing the environmental condition in diseased cellular stress state. Osmolytes are present in different organisms, including microorganisms, animals and plants...
November 11, 2017: International Journal of Biological Macromolecules
Mohammad Pazhang, Narges Mardi, Faramarz Mehrnejad, Nader Chaparzadeh
Inside the cells, proteins are surrounded by mixtures of different osmolytes. However, our current understanding of the combinatorial effects of such mixtures on the stability of proteins remains elusive. In the present study, the stability and structure of recombinant pyrazinamidase (PZase) from Mycobacterium tuberculosis were analyzed in the presence of stabilizing osmolytes (sorbitol, sucrose and glycerol) and alcohols (methanol, ethanol, isopropanol and n-propanol). The far-UV and near-UV circular dichroism (CD), intrinsic fluorescence and thermostability results indicated that methanol, unexpectedly, has stronger effect on destabilization of the enzyme compared to ethanol which has larger log P...
November 9, 2017: International Journal of Biological Macromolecules
Leandro Martinez, Seishi Shimizu
Preferential solvation is a fundamental parameter for the interpretation of solubility and solute structural stability. The molecular basis for solute-solvent interactions can be obtained through distribution functions, and the thermodynamic connection to experimental data depends on the computation of distribution integrals, specifically Kirkwood-Buff integrals for the determination of preferential interactions. Standard radial distribution functions, however, are not convenient for the study of the solvation of complex, non-spherical solutes, as proteins...
November 9, 2017: Journal of Chemical Theory and Computation
Yingcai Song, Bing Zhang, Fei Guo, Maojun Yang, Yang Li, Zhi-Qiang Liu
The mechanosensitive channel of small conductance (MscS) is a bacterial membrane pore that senses membrane tension and protects cells from lysis by releasing osmolytes. MscS is a homoheptameric channel with a cytoplasmic domain with seven portals and a β-barrel opening to the cytoplasm. TtMscS, an MscS channel from Thermoanaerobacter tengcongensis, is an anion-selective channel. A previous study from our laboratory has defined the crucial role of β-barrel in the anion selectivity of TtMscS (Zhang et al., 2012)...
2017: Frontiers in Physiology
Jong-Suep Baek, Chee Chong Choo, Nguan Soon Tan, Say Chye Joachim Loo
Polymeric particulate delivery systems are vastly explored for the delivery of chemotherapeutic agents. However, the preparation of polymeric particulate systems with the capability of providing sustained release of two or more drugs is still a challenge. Herein, poly (D, L-lactic-co-glycolic acid, 50:50) hollow microparticles co-loaded with doxorubicin and paclitaxel were developed through double-emulsion solvent evaporation technique. Hollow microparticles were formed through the addition of an osmolyte into the fabrication process...
October 6, 2017: Oncotarget
Shahar Sukenik, Shaked Dunsky, Avishai Barnoy, Ilan Shumilin, Daniel Harries
Under environmental duress, many organisms accumulate large amounts of osmolytes - molecularly small organic solutes. Osmolytes are known to counteract stress, driving proteins to their compact native states by their exclusion from protein surfaces. In contrast, the effect of osmolytes on lipid membranes is poorly understood and widely debated. Many fully membrane-permeable osmolytes exert an apparent attractive force between lipid membranes, yet all proposed models fail to fully account for the origin of this force...
November 7, 2017: Physical Chemistry Chemical Physics: PCCP
Gayathri Ilangumaran, Donald L Smith
Salinity affects plant growth and is a major abiotic stress that limits crop productivity. It is well-understood that environmental adaptations and genetic traits regulate salinity tolerance in plants, but imparting the knowledge gained towards crop improvement remain arduous. Harnessing the potential of beneficial microorganisms present in the rhizosphere is an alternative strategy for improving plant stress tolerance. This review intends to elucidate the understanding of salinity tolerance mechanisms attributed by plant growth promoting rhizobacteria (PGPR)...
2017: Frontiers in Plant Science
Chun-Yang Li, Dian Zhang, Xiu-Lan Chen, Peng Wang, Wei-Ling Shi, Ping-Yi Li, Xi-Ying Zhang, Qi-Long Qin, Jonathan D Todd, Yu-Zhong Zhang
The marine osmolyte dimethylsulfoniopropionate (DMSP) is one of Earth's most abundant organosulfur molecules. Bacterial DMSP lyases cleave DMSP, producing acrylate and dimethyl sulfide (DMS), a climate-active gas with roles in global sulfur cycling and atmospheric chemistry. DddY is the only known periplasmic DMSP lyase and is present in β-, γ-, δ- and ε-proteobacteria. Unlike other known DMSP lyases, DddY has not been classified into a protein superfamily, and its structure and catalytic mechanism are unknown...
October 26, 2017: Journal of Molecular Biology
Carmen Perez-Laso, Sebastián Cerdan, Carme Junque, Ángel Gómez, Esperanza Ortega, Mireia Mora, Carlos Avendaño, Esther Gómez-Gil, María Cruz Rodríguez Del Cerro, Antonio Guillamon
Androgenization in adult natal women, as in transsexual men (TM), affects brain cortical thickness and the volume of subcortical structures. In order to understand the mechanism underlying these changes we have developed an adult female rat model of androgenization. Magnetic resonance imaging and spectroscopy were used to monitor brain volume changes, white matter microstructure and ex vivo metabolic profiles over 32 days in androgenized and control subjects. Supraphysiological doses of testosterone prevents aging decrease of fractional anisotropy values, decreased general cortical volume and the relative concentrations of glutamine (Gln) and myo-Inositol (mI)...
July 6, 2017: Cerebral Cortex
Laura Czech, Sebastian Poehl, Philipp Hub, Nadine Stoeveken, Erhard Bremer
Ectoine and hydroxyectoine are widely synthesized by members of the Bacteria and a few Archaea as potent osmostress protectants. We have studied the salient features of the osmostress-responsive promoter directing the transcription of the ectoine/hydroxyectoine biosynthetic gene cluster from the plant-roots-associated bacterium Pseudomonas stutzeri by transferring it into Escherichia coli, an enterobacterium that does not produce ectoines naturally. Using ect-lacZ reporter fusions, we found that the heterologous ect promoter reacted with exquisite sensitivity in its transcriptional profile to graded increases in sustained high salinity, responded to a true osmotic signal, and required the build-up of an osmotically effective gradient across the cytoplasmic membrane for its induction...
November 3, 2017: Applied and Environmental Microbiology
Minglei Ren, Guiying Zhang, Zi Ye, Zhixian Qiao, Meili Xie, Yan Lin, Tao Li, Jindong Zhao
Disentangling the interactions between cyanobacteria and associated bacterial community is important for understanding the mechanisms that mediate the formation of cyanobacterial blooms in freshwater ecosystems. Despite the fact that a metagenomic approach enables researchers to profile the structure of microbial communities associated with cyanobacteria, reconstructing genome sequences for all members remains inefficient, due to the inherent enormous microbial diversity. Here, we have established a stable coculture system under high salinity, originally from a mixture of an axenic cyanobacterium Synechococcus sp...
November 2, 2017: AMB Express
Pramod Kumar Verma, Achintya Kundu, Matthew Puretz, Charvanaa Dhoonmoon, Oriana S Chegwidden, Casey H Londergan, Minhaeng Cho
Water is an extensively self-associated liquid due to its extensive hydrogen bond (H-bond) forming ability. The resulting H-bonded network fluid exhibits nearly continuous absorption of light from the te-rahertz to the near-IR region. The relatively weak bend-libration water combination band (centered at 2130 cm(-1)) has been largely overlooked as a reporter of liquid water's structure and dynamics despite its location in a convenient region of the IR for spectroscopic study. The intermolecular nature of the com-bination band leads to a unique absorption signal that reports collectively on the rigidity of the H-bonding network in the presence of many different solutes...
November 2, 2017: Journal of Physical Chemistry. B
Matthias Schmidt, Heidrun Sigrid Windisch, Kai-Uwe Ludwichowski, Sean Lando Levin Seegert, Hans-Otto Pörtner, Daniela Storch, Christian Bock
Background: Exposure to future ocean acidification scenarios may alter the behaviour of marine teleosts through interference with neuroreceptor functioning. So far, most studies investigated effects of ocean acidification on the behaviour of fish, either isolated or in combination with environmental temperature. However, only few physiological studies on this issue were conducted despite the putative neurophysiological origin of the CO2-induced behavioural changes. Here, we present the metabolic consequences of long-term exposure to projected ocean acidification (396-548 μatm PCO2 under control and 915-1272 μatm under treatment conditions) and parallel warming in the brain of two related fish species, polar cod (Boreogadus saida, exposed to 0 °C, 3 °C, 6 °C and 8 °C) and Atlantic cod (Gadus morhua, exposed to 3 °C, 8 °C, 12 °C and 16 °C)...
2017: Frontiers in Zoology
Yusuke S Kato, Masaru Tanokura, Takashi Kuzuhara
The influenza A virus, which has an RNA genome, requires RNA-dependent RNA polymerase for transcription and replication. The polymerase is comprised of the subunits PA, PB1, and PB2. The C-terminal RNA-binding domain in PB2 contains lysine 627 (PB2 627), which is associated with pathogenicity and host range. However, the structure and molecular mechanism of PB2 627 in solution remain obscure. Here, we investigated PB2 627 in solution by nuclear magnetic resonance (NMR) and detected inhomogeneity in the intensities of backbone amide proton signals due to local fluctuations in structure...
December 2017: Biochemistry and Biophysics Reports
Evandro Alves Vieira, Kleber Resende Silva, Aline Oriani, Camila Fernandes Moro, Marcia Regina Braga
Rocky outcrops represent the diversity center of vascular desiccation tolerant (DT) plants. Vegetation in this environment is exposed to an extended dry season and extreme conditions due to rocky soils and high sun exposure. In this study, we demonstrated that Pitcairnia burchellii, a bromeliad from rocky outcrops, tolerates intense desiccation for about 90 days due to strategies as accumulation of compatible osmolytes and antioxidant substances together with leaf morphological changes. In dehydrated plants, an increase in antioxidant activity was observed and the vacuolization of parenchyma cells was accompanied by proline accumulation in leaves and rhizomes...
October 10, 2017: Plant Physiology and Biochemistry: PPB
Fernando M Romero, Santiago J Maiale, Franco R Rossi, Maria Marina, Oscar A Ruíz, Andrés Gárriz
Plants have developed different strategies to cope with the environmental stresses they face during their life cycle. The responses triggered under these conditions are usually characterized by significant modifications in the metabolism of polyamines such as putrescine, spermidine, and spermine. Several works have demonstrated that a fine-tuned regulation of the enzymes involved in the biosynthesis and catabolism of polyamines leads to the increment in the concentration of these compounds. Polyamines exert different effects that could help plants to deal with stressful conditions...
2018: Methods in Molecular Biology
Noel Edwards, Catriona M H Anderson, Nichola J Conlon, Andrew K Watson, Rebecca J Hall, Timothy R Cheek, T Martin Embley, David T Thwaites
Amino acid transporters are essential components of prokaryote and eukaryote cells, possess distinct physiological functions, and differ markedly in substrate specificity. Amino acid transporters can be both drug targets and drug transporters (bioavailability, targeting) with many monogenic disorders resulting from dysfunctional membrane transport. The largest collection of amino acid transporters (including the mammalian SLC6, SLC7, SLC32, SLC36, and SLC38 families), across all kingdoms of life, is within the Amino acid-Polyamine-organoCation (APC) superfamily...
October 23, 2017: Cellular and Molecular Life Sciences: CMLS
Tatiana B Eronina, Valeriya V Mikhaylova, Natalia A Chebotareva, Vera A Borzova, Igor K Yudin, Boris I Kurganov
To characterize the initial stages of protein aggregation, the kinetics of aggregation of UV-irradiated glycogen phosphorylase b (UV-Phb) was studied under conditions when the aggregation proceeded at a low rate (10°C, 0.03M Hepes buffer, pH6.8, containing 0.1M NaCl). Aggregation of UV-Phb was induced by polyethylene glycol and Ficoll-70, acting as crowders, or a natural osmolyte trimethylamine N-oxide (TMAO). It has been shown that the initial rate of the stage of aggregate growth is proportional to the protein concentration squared, suggesting that the order of aggregation with respect to the protein is equal to two...
October 18, 2017: Biophysical Chemistry
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