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161.
Jorgen Ravoet Jafar Maharramov Ivan Meeus Lina De Smet Tom Wenseleers Guy Smagghe Dirk C. de Graaf 《PloS one》2013,8(8)
Since the last decade, unusually high honey bee colony losses have been reported mainly in North-America and Europe. Here, we report on a comprehensive bee pathogen screening in Belgium covering 363 bee colonies that were screened for 18 known disease-causing pathogens and correlate their incidence in summer with subsequent winter mortality. Our analyses demonstrate that, in addition to Varroa destructor, the presence of the trypanosomatid parasite Crithidia mellificae and the microsporidian parasite Nosema ceranae in summer are also predictive markers of winter mortality, with a negative synergy being observed between the two in terms of their effects on colony mortality. Furthermore, we document the first occurrence of a parasitizing phorid fly in Europe, identify a new fourth strain of Lake Sinai Virus (LSV), and confirm the presence of other little reported pathogens such as Apicystis bombi, Aphid Lethal Paralysis Virus (ALPV), Spiroplasma apis, Spiroplasma melliferum and Varroa destructor Macula-like Virus (VdMLV). Finally, we provide evidence that ALPV and VdMLV replicate in honey bees and show that viruses of the LSV complex and Black Queen Cell Virus tend to non-randomly co-occur together. We also noticed a significant correlation between the number of pathogen species and colony losses. Overall, our results contribute significantly to our understanding of honey bee diseases and the likely causes of their current decline in Europe. 相似文献
162.
Ali Reza Noori Saman Hosseinkhani Parisa Ghiasi Akbar Heydari Jafar Akbari 《Engineering in Life Science》2013,13(2):201-209
Ionic liquids (IL) are used as a new class of solvents for various reactions. Especially using IL in biocatalysis in an aqueous milieu has attracted considerable attention because enzymes show remarkable differences in their catalytic features in IL‐containing reaction media. Firefly luciferase is widely used in many analytical techniques, because light production of firefly luciferase is one of the most sensitive analytical measures in the ultrasensitive detection of adenosine‐5′‐triphosphate, e.g. for measuring microbial contamination and monitoring gene expression, as well as for monitoring tumor growth and metastasis in whole animals. Firefly luciferase is an unstable enzyme and its inactivation can lead to low sensitivity in the above‐mentioned assays. The present study addresses the comparative influence of six different water‐immiscible IL, the 3‐methylimidazolium derivatives [BMIM]Cl, [HMIM]Cl, [BMIM]Br, [EMIM]Br, [HMIM]Br, and [BMIM]BF4, on the kinetic properties, structural stability, and function of firefly luciferase from Photinus pyralis using circular dichroism, fluorescence spectroscopy, and a bioluminescence assay. The incubation of luciferase with various IL showed that, with the exception of [BMIM]BF4, the activity and stability of luciferase was considerably increased in the presence of IL, compared to luciferase in aqueous medium. Moreover, Km for the substrate adenosine‐5′‐triphosphate in the presence of IL (except for [BMIM]BF4) decreased while Km for luciferin remained constant. 相似文献
163.
Thilo Rühle Jafar Angouri Razeghi Evgenia Vamvaka Stefania Viola Chiara Gandini Tatjana Kleine Danja Schünemann Roberto Barbato Peter Jahns Dario Leister 《Plant physiology》2014,165(1):207-226
The chloroplast F1Fo-ATP synthase/ATPase (cpATPase) couples ATP synthesis to the light-driven electrochemical proton gradient. The cpATPase is a multiprotein complex and consists of a membrane-spanning protein channel (comprising subunit types a, b, b′, and c) and a peripheral domain (subunits α, β, γ, δ, and ε). We report the characterization of the Arabidopsis (Arabidopsis thaliana) CONSERVED ONLY IN THE GREEN LINEAGE160 (AtCGL160) protein (AtCGL160), conserved in green algae and plants. AtCGL160 is an integral thylakoid protein, and its carboxyl-terminal portion is distantly related to prokaryotic ATP SYNTHASE PROTEIN1 (Atp1/UncI) proteins that are thought to function in ATP synthase assembly. Plants without AtCGL160 display an increase in xanthophyll cycle activity and energy-dependent nonphotochemical quenching. These photosynthetic perturbations can be attributed to a severe reduction in cpATPase levels that result in increased acidification of the thylakoid lumen. AtCGL160 is not an integral cpATPase component but is specifically required for the efficient incorporation of the c-subunit into the cpATPase. AtCGL160, as well as a chimeric protein containing the amino-terminal part of AtCGL160 and Synechocystis sp. PCC6803 Atp1, physically interact with the c-subunit. We conclude that AtCGL160 and Atp1 facilitate the assembly of the membranous part of the cpATPase in their hosts, but loss of their functions provokes a unique compensatory response in each organism.The majority of cellular energy is stored in the form of ATP synthesized by the ubiquitous F1Fo-ATP synthase (F1 stands for coupling factor 1, Fo for coupling factor o), which is found in the energy-transducing membranes of bacteria, mitochondria, and chloroplasts. The chloroplast F1Fo-ATP synthase/ATPase (cpATPase) is a rotary motor that is responsible for coupling ATP synthesis (and hydrolysis) to the light-driven electrochemical proton gradient. The cpATPase comprises two physically separable parts, chloroplast coupling factor o (CFo), which is an integral membrane-spanning proton channel, and chloroplast coupling factor 1 (CF1), which is located peripheral to the membrane and contains the catalytic site(s) for reversible ATP synthesis (for review, see von Ballmoos et al., 2009). CFo comprises four different subunit types, designated b (synonymously, I or AtpF), b′ (II or AtpG), c (III or AtpH), and a (IV or AtpI), and contains one each of subunits a, b, and b′ and a ring made up of 14 copies of subunit c. CF1 comprises five different subunits, α (AtpA), β (AtpB), γ (AtpC), δ (AtpD), and ε (AtpE), and its subunit composition is α3β3γδε (for review, see von Ballmoos et al., 2009).The passage of protons through the CFo motor drives rotation of the ring of c-subunits, which together form a rotor. The c-ring is connected to subunit γ, and rotation of γ causes conformational changes in the catalytic nucleotide-binding sites of the CF1 motor, resulting in the synthesis and release of ATP (for review, see Okuno et al., 2011). This process is made possible by the fact that CF1 and CFo are physically connected by two stalks, a central one containing the ε- and γ-subunits and a peripheral one made up of δ, b, and b′ (for review, see Böttcher and Gräber, 2000; Weber, 2007). There are six nucleotide-binding sites in CF1, one at each of the αβ-subunit interfaces about halfway along the vertical axis of the hexamer. Three of the sites are located primarily on the β-subunits and are catalytic; the other three are noncatalytic and probably regulatory. While the three-dimensional structure of the α3β3 hexamer in chloroplasts has been solved to a resolution of 3.2 Å (Groth and Pohl, 2001), the structure of the entire CFo has not yet been determined. However, the conformation of the ring-forming part of CFo from spinach (Spinacia oleracea) chloroplasts has been defined and found to consist of 14 c-units (Vollmar et al., 2009), whereas the c-ring of the ATP synthase from the cyanobacterium Spirulina platensis contains 15 units (Pogoryelov et al., 2009).Similar to other thylakoid multiprotein complexes like PSII and PSI as well as the cytochrome b6f complex (Cyt b6f), the assembly of the ATP synthase must be tightly regulated. Moreover, the variable stoichiometry of the constituents of F1 (three α/β-subunits versus one each of γ, δ, and ε) and Fo (10–15 c-subunits versus one each of a, b, and b′) requires coordination of the expression of the corresponding genes. This is particularly important in eukaryotes, where the genes are located in different compartments, for instance, in the case of the cpATPase, in the plastid (for α, β, ε, a, b, and c) and the nucleus (for b′, γ, and δ).The assembly of ATP synthase has been most extensively studied in Saccharomyces cerevisiae mitochondria, leading to the identification of several factors involved in this process (for review, see Rak et al., 2009). Thus, three proteins in yeast are known to be involved in the assembly of the α3β3 hexamer of F1. Atp11p (Ackerman and Tzagoloff, 1990a; Wang and Ackerman, 1996) and Atp12p (Ackerman and Tzagoloff, 1990a; Wang and Ackerman, 1998) code for mitochondrial proteins that interact with the β- and α-subunits, respectively, to promote their assembly into the oligomeric F1-ATPase, and the absence of either protein causes the α- and β-subunits to aggregate into insoluble inclusion bodies in the mitochondrial matrix. Lack of the third protein, FORMATION OF MITOCHONDRIAL COMPLEXES1 (Fmc1p), is associated with aggregation of the α- and β-subunits under heat stress, suggesting that Fmc1p is required for correct folding of Atp12p at elevated temperatures (Lefebvre-Legendre et al., 2001). Originally, the c-ring was assumed to form spontaneously (Arechaga et al., 2002), but subsequent studies have indicated that the assembly of this structural component is also a protein-assisted process. Thus, Atp25p is required for both the synthesis of the c-subunit and its oligomerization into a ring structure of the proper size (Zeng et al., 2008). Moreover, Atp10p (Ackerman and Tzagoloff, 1990b), Atp23p (Osman et al., 2007), and OXIDASE ASSEMBLY1 (Oxa1p) (Jia et al., 2007) are involved in Fo assembly in yeast mitochondria.In prokaryotes, two ATP synthase assembly factors have been described in detail. The membrane protein insertase YidC belongs to the Oxa1 family, is required in vitro for the membrane insertion of subunit c, and assists in the formation of the c-ring from monomers (van der Laan et al., 2004; Kol et al., 2008). In bacterial genomes, the atp1/uncI genes typically precede the genes encoding the structural subunits of the F1Fo-ATP synthase (for review, see Kol et al., 2008). Moreover, in Synechocystis sp. PCC6803, sll1321/atp1 is coordinately expressed with the seven other genes in the ATP synthase operon (Grossman et al., 2010), implying that Sll1321/Atp1 might have a function associated with the ATP synthase. The genes atp1 and uncI code for small proteins; for instance, Synechocystis sp. PCC6803 Sll1321 has 117 amino acids, and Escherichia coli UncI has 130 amino acids. The function of Atp1/UncI has long remained elusive because deletion of uncI in E. coli results merely in a slightly reduced growth yield (Gay, 1984), indicating that the protein is not essential for the formation of the F1Fo-ATP synthase complex. Similarly, in the alkaliphilic Bacillus pseudofirmus OF4, Atp1/UncI is not absolutely required for ATP synthase function, and a B. pseudofirmus strain deleted for the atp1 gene could still grow nonfermentatively and its purified ATP synthase had a c-ring of normal size (Liu et al., 2013). Recently, a hybrid F1Fo (F1 from Bacillus PS3 and Fo from Propionigenium modestum) was expressed in E. coli. In this system, P. modestum Atp1/UncI was found to be indispensable for c-ring formation and coupled ATPase activity (Suzuki et al., 2007). Similarly, functional production of the Na+ F1Fo-ATP synthase from Acetobacterium woodii in E. coli required the A. woodii atp1/uncI gene for proper assembly (Brandt et al., 2013). Moreover, because subunit c monomers, as well as assembled c-rings, can be copurified together with P. modestum UncI/Atp1 (Suzuki et al., 2007) and the oligomerization of P. modestum c-subunits into c11-rings is mediated by Atp1/UncI in vitro (Ozaki et al., 2008), Atp1/UncI seems to play a role in c-ring assembly for some bacterial ATP synthases.In plants and green algae, regulation of the biogenesis of the cpATPase is well understood at the level of translation of CF1 subunits (Drapier et al., 2007). Thus, synthesis of the nucleus-encoded subunit γ is required for sustained translation of the chloroplast-encoded subunit β, which in turn transactivates the translation of chloroplast-encoded subunit α. Translational down-regulation of subunit β or α, when not assembled, involves the 5′ untranslated regions (UTRs) of their own mRNAs, pointing to control at the level of translation initiation. In addition, a negative feedback exerted by α/β assembly intermediates on the translation of subunit β can be released when subunit γ assembles with α3β3 hexamers.Our knowledge of the nature of true assembly factors for the cpATPase is scarce. So far, only the ALBINO3 homolog Alb4 protein, which can functionally substitute for YidC in E. coli, has been shown to play a role in the biogenesis of the cpATPase, possibly by stabilizing or promoting the assembly of CF1 during its attachment to the CFo portion (Benz et al., 2009). Thus, Alb4-Oxa1p-YidC represents an ATP synthase assembly factor family that is conserved between prokaryotes, yeast, and plants. For the bacterial Atp1/UncI protein, one homolog exists in yeast, Vma21p, which is an integral membrane protein localized to the endoplasmic reticulum and is required for vacuolar H+-ATPase biogenesis (Graham et al., 1998).In this study, we have identified and characterized a knockout mutant for Arabidopsis (Arabidopsis thaliana) CGL160, a protein that displays moderate similarity to prokaryotic Atp1/UncI proteins in its C-terminal domain. AtCGL160 is required for the efficient assembly of the cpATPase, but lack of AtCGL160 in Arabidopsis has more severe effects on cpATPase assembly than those reported in the literature for inactivation of its prokaryotic relatives and can be located to the assembly of c-subunits into the membranous subcomplex. AtCGL160 physically interacts with the c-subunit of CFo, and, interestingly, Atp1 can replace the C-terminal part of AtCGL160 in such interactions, indicating that the function of Atp1 and CGL160 proteins is conserved. 相似文献
164.
Mehrdad Moosazadeh Moghaddam Kamal Azizi Barjini Mahdi Fasihi Ramandi Jafar Amani 《World journal of microbiology & biotechnology》2014,30(5):1533-1540
With the growing microbial resistance to conventional antimicrobial agents, the development of novel and alternative therapeutic strategies are vital. During recent years novel peptide antibiotics with broad spectrum activity against many Gram-positive and Gram-negative bacteria have been developed. In this study, antibacterial activity of CM11 peptide (WKLFKKILKVL-NH2), a short cecropin–melittin hybrid peptide, is evaluated against antibiotic-resistant strains of Klebsiella pneumoniae and Salmonella typhimurium as two important pathogenic bacteria. To appraise the antibacterial activity, minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and bactericidal killing assay were utilized with different concentrations (2–128 mg/L) of peptide. To evaluate cytotoxic effect of peptide, viability of RAJI, Hela, SP2/0, CHO, LNCAP cell lines and primary murine macrophage cells were also investigated with MTT assay in different concentrations (3–24 and 0.5–16 mg/L, respectively). MICs of K. pneumoniae and S. typhimurium isolates were in range of 8–16 and 4–16 mg/L, respectively. In bactericidal killing assay no colonies were observed at 2X MIC for K. pneumoniae and S. typhimurium isolates after 80–90 min, respectively. Despite the fact that CM11 reveals no significant cytotoxicity on RAJI, Hela, SP2/0, and CHO cell lines beneath 6 mg/L at first 24 and 48 h, the viability of LNCAP cells are about 50 % at 3 mg/L, which indicates strong cytotoxicity of the peptide. In addition, macrophage toxicity by MTT assay showed that LD50 of CM11 peptide is 12 μM (16 mg/L) after 48 h while in this concentration after 24 h macrophage viability was about 70 %. 相似文献
165.
Nemat Mahmoudi Mohammad Reza Ahmadi Manoochehr Babanezhad Jafar Seyfabadi 《Aquatic Ecology》2014,48(3):351-365
Main and interaction effects of environmental parameters on variations of chlorophyll-a along the coast of the southern Caspian Sea were determined. Parameters such as temperature, conductivity, turbidity salinity, dissolved oxygen (DO), pH, chlorophyll-a and nutrients were evaluated monthly in four transects and different depths (0, 5, 10, 20, 35 and 50 m), using multiple regression and grey relational analysis. Additionally, the long-term data (1994–2009) on the seasonal phytoplanktonic variation were included in our discussion. There was a good agreement between the observed and predicted values in the models that included the interaction effects during spring, summer, autumn and winter, with the adjusted R 2 of 0.64, 0.63, 0.60 and 0.54, respectively. Temperature and its interactions were found to be the most important factor on chlorophyll-a throughout the year. Overall, the most effective factors were seasonally categorized as: organic phosphorus, ammonium and their interactions (spring); organic phosphorus, nitrate, DO, silica and their interactions (summer); organic phosphorus, pH, DO and their interactions (autumn); pH, ammonium, DO and their interactions (winter). Thermocline, riverine transport, nitrification and the presence of Mnemiopsis leidyi and Cyanophyta were found to be the most important phenomena affecting the dynamics of nutrients and phytoplanktonic biomass in the area. In the distribution of chlorophyll-a, the interaction effects of different environmental parameters proved to be more important than their individual effects. The multiple regression and grey analyses were also found to be useful tools to understand the interactions between phytoplankton and environmental factors. 相似文献
166.
Emmy H. Rannikko Louise Buur Vesterager Jafar H. A. Shaik Stephanie S. Weber Karina Fog Poul H. Jensen Philipp J. Kahle 《Journal of neurochemistry》2013,125(2):314-327
DJ‐1 is a ubiquitous protein regulating cellular viability. Recessive mutations in the PARK7/DJ‐1 gene are linked to Parkinson's disease (PD). Although the most dramatic L166P point mutation practically eliminates DJ‐1 protein and function, the effects of other PD‐linked mutations are subtler. Here, we investigated two recently described PD‐associated DJ‐1 point mutations, the A179T substitution and the P158Δ in‐frame deletion. [A179T]DJ‐1 protein was as stable as wild‐type [wt]DJ‐1, but the P158Δ mutant protein was less stable. In accord with the notion that dimer formation is essential for DJ‐1 protein stability, [P158Δ]DJ‐1 was impaired in dimer formation. Similar to our previous findings for [M26I]DJ‐1, [P158Δ]DJ‐1 bound aberrantly to apoptosis signal‐regulating kinase 1. Thus, the PD‐associated P158Δ mutation destabilizes DJ‐1 protein and function. As there is also evidence for an involvement of DJ‐1 in multiple system atrophy, a PD‐related α‐synucleinopathy characterized by oligodendroglial cytoplasmic inclusions, we studied an oligodendroglial cell line stably expressing α‐synuclein. α‐Synuclein aggregate dependent microtubule retraction upon co‐transfection with tubulin polymerization‐promoting protein p25α was ameliorated by [wt]DJ‐1. In contrast, DJ‐1 mutants including P158Δ failed to protect in this system, where we found evidence of apoptosis signal‐regulating kinase 1 (ASK1) involvement. In conclusion, the P158Δ point mutation may contribute to neurodegeneration by protein destabilization and hence loss of DJ‐1 function. 相似文献
167.
Mohamad Ali Roozegar Tayebeh Malek Mohammadi Mohamad Reza Havasian Jafar Panahi Amirreza Hashemian Mansur Amraei Behzad Hoshmand 《Bioinformation》2015,11(2):96-100
Periodontium is a complex organ composed of mineralized epithelial and connective tissue. Dexamethasone could stimulate
proliferation of osteoblast and fibroblasts. This study aimed to assess the osteogenic effect of dexamethasone on periodental
ligament (PDL) stem cells. PDL stem cells were collected from periodontal ligament tissue of root of extracted premolar of young
and healthy people. The stem cells were cultured in α-MEM Medium in three groups, one group with basic medium contains (α-
MEM and FBS 10 % and 50 mmol of β_ gelisrophosphat and L_ ascorbic acid µg/ml), the second group: basic medium with
dexamethasone and the third one: basic medium without any osteogenic stimulant. Mineralization of cellular layer was analyzed
with Alizarin red stain method. Osteogenic analysis was done by Alkaline phosphates and calcium test. These analysis indicated
that the amount of intra-cellular calcium and alkaline phosphates in the Dexamethasone group was far more than the control and
basic group (P<0.05). The results of Alizarin red stain indicated more mineralization of cultured cells in Dexamethasone group
(P<0.05). The study results showed that Dexamethasone has significant osteogenic effect on PDL stem cells and further studies are
recommended to evaluate its effect on treatment of bone disorders. 相似文献
168.
Biotechnology Letters - Based on observations indicating that the γ-carboxylase enzyme has a lower affinity for the protein C (PC) propeptide and that the γ-carboxylase region in the PC... 相似文献
169.
Sequencing of 15 622 gene‐bearing BACs clarifies the gene‐dense regions of the barley genome
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MingCheng Luo Kavitha Madishetty Jan T. Svensson Matthew J. Moscou Steve Wanamaker Tao Jiang Andris Kleinhofs Gary J. Muehlbauer Roger P. Wise Nils Stein Yaqin Ma Edmundo Rodriguez Dave Kudrna Prasanna R. Bhat Shiaoman Chao Pascal Condamine Shane Heinen Josh Resnik Rod Wing Heather N. Witt Matthew Alpert Marco Beccuti Serdar Bozdag Francesca Cordero Hamid Mirebrahim Rachid Ounit Yonghui Wu Frank You Jie Zheng Hana Simková Jaroslav Dolezel Jane Grimwood Jeremy Schmutz Denisa Duma Lothar Altschmied Tom Blake Phil Bregitzer Laurel Cooper Muharrem Dilbirligi Anders Falk Leila Feiz Andreas Graner Perry Gustafson Patrick M. Hayes Peggy Lemaux Jafar Mammadov Timothy J. Close 《The Plant journal : for cell and molecular biology》2015,84(1):216-227
Barley (Hordeum vulgare L.) possesses a large and highly repetitive genome of 5.1 Gb that has hindered the development of a complete sequence. In 2012, the International Barley Sequencing Consortium released a resource integrating whole‐genome shotgun sequences with a physical and genetic framework. However, because only 6278 bacterial artificial chromosome (BACs) in the physical map were sequenced, fine structure was limited. To gain access to the gene‐containing portion of the barley genome at high resolution, we identified and sequenced 15 622 BACs representing the minimal tiling path of 72 052 physical‐mapped gene‐bearing BACs. This generated ~1.7 Gb of genomic sequence containing an estimated 2/3 of all Morex barley genes. Exploration of these sequenced BACs revealed that although distal ends of chromosomes contain most of the gene‐enriched BACs and are characterized by high recombination rates, there are also gene‐dense regions with suppressed recombination. We made use of published map‐anchored sequence data from Aegilops tauschii to develop a synteny viewer between barley and the ancestor of the wheat D‐genome. Except for some notable inversions, there is a high level of collinearity between the two species. The software HarvEST:Barley provides facile access to BAC sequences and their annotations, along with the barley–Ae. tauschii synteny viewer. These BAC sequences constitute a resource to improve the efficiency of marker development, map‐based cloning, and comparative genomics in barley and related crops. Additional knowledge about regions of the barley genome that are gene‐dense but low recombination is particularly relevant. 相似文献
170.