Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Journal of Applied Phytotechnology in Environmental Sanitation , 2013,
Abstract: This study aims to investigate the influence of 10 varying frequencies (5.0 × 10-3 to 1.0 × 102 Hz) of alternating magnetic fields on Oryza sativa L. var. IR8 seed germination and seedling development. Methods:Oryza sativa L. var. IR8 seeds were exposed once to varying frequencies of alternating magnetic fields generated by a Helmholtz coil system. Seed germination was evaluated through a 5-day daily cumulative percentage of germination count, corrected germination rate index (CGRI) calculations, α-amylase assay, and apparent amylose content determination, whereas seed development was evaluated through its shoot and root growth rates and fresh and dry weights. Results:Results showed that, with varying frequencies of magnetic fields, it promoted an early onset of seed germination and a faster germination rate, but in its final seed germination, the α-amylase activity and amylose content were not affected. Shoot and root growth rates and fresh and dry weights were likewise found to be not significantly different from its control. Conclusion: Alternating magnetic fields may serve as a beneficial pretreatment to break the rice seed dormancy and increase its rate of seed germination.
Anti-inflammatory effects of spermidine in lipopolysaccharide-stimulated BV2 microglial cells
Yung Choi, Hye Park
Journal of Biomedical Science , 2012, DOI: 10.1186/1423-0127-19-31
Abstract: The anti-inflammatory properties of spermidine were studied using lipopolysaccharide (LPS)-stimulated murine BV2 microglia model. As inflammatory parameters, the production of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin (IL)-6 and tumor necrosis factor (TNF)-α were evaluated. We also examined the spermidine's effect on the activity of nuclear factor-kappaB (NF-κB), and the phosphoinositide 3-kinase (PI3K)/Akt and mitogen-activated protein kinases (MAPKs) pathways.Pretreatment with spermidine prior to LPS treatment significantly inhibited excessive production of NO and PGE2 in a dose-dependent manner, and was associated with down-regulation of expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Spermidine treatment also attenuated the production of pro-inflammatory cytokines, including IL-6 and TNF-α, by suppressing their mRNA expressions. The mechanism underlying spermidine-mediated attenuation of inflammation in BV2 cells appeared to involve the suppression of translocation of NF-κB p65 subunit into the nucleus, and the phosphorylation of Akt and MAPKs.The results indicate that spermidine appears to inhibit inflammation stimulated by LPS by blocking the NF-κB, PI3K/Akt and MAPKs signaling pathways in microglia.Microglia are glial cells that function as the prime effector cells in the immune defense and inflammatory responses in the central nervous system (CNS) [1-3]. These cells are activated in response to environmental stress and produce various bioactive molecules, including nitric oxide (NO), prostaglandin E2 (PGE2), reactive oxygen species, and pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, which function to restore CNS homeostasis by clearing damaged cells and debris [4,5]. However, prolonged microglial activation can cause chronic neuroinflammation and promote neuronal injury due to increased production of neurotoxic pro-inflammatory mediators, and can eventually le
The Biological Response of Spermidine Induced by Ionization Radiation  [PDF]
Changhyun Roh,Dong-Kyung Yu,Insub Kim,Sung Kee Jo
Molecules , 2012, DOI: 10.3390/molecules17010145
Abstract: Globally, there are concerns over the risks associated with radiation exposure, so it is important to understand the biological effects of radiation exposure. Driven by the need to detect the presence of radiation exposure, biomarkers to monitor potential exposure after radiological accidents can be developed and would be extremely valuable for biological response. In this study, the behavior of spermidine as a biomarker was investigated in a C57BL/6 mouse model exposed to an acute whole-body sublethal dose of 6 Gy. The spermidine content values in serum increased for up to two days after 6 Gy irradiation. However, the enhanced spermidine content observed on day +3 in irradiated mice returned to normal levels on the subsequent five days. The result indicates that spermidine can be used as a biomarker of biological response to radiation exposure.
Effect of Spermidine on Misfolding and Interactions of Alpha-Synuclein  [PDF]
Alexey V. Krasnoslobodtsev, Jie Peng, Josephat M. Asiago, Jagadish Hindupur, Jean-Christophe Rochet, Yuri L. Lyubchenko
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038099
Abstract: Alpha-synuclein (α-Syn) is a 140 aa presynaptic protein which belongs to a group of natively unfolded proteins that are unstructured in aqueous solutions. The aggregation rate of α-Syn is accelerated in the presence of physiological levels of cellular polyamines. Here we applied single molecule AFM force spectroscopy to characterize the effect of spermidine on the very first stages of α-Syn aggregation – misfolding and assembly into dimers. Two α-Syn variants, the wild-type (WT) protein and A30P, were studied. The two protein molecules were covalently immobilized at the C-terminus, one at the AFM tip and the other on the substrate, and intermolecular interactions between the two molecules were measured by multiple approach-retraction cycles. At conditions close to physiological ones at which α-Syn misfolding is a rare event, the addition of spermidine leads to a dramatic increase in the propensity of the WT and mutant proteins to misfold. Importantly, misfolding is characterized by a set of conformations, and A30P changes the misfolding pattern as well as the strength of the intermolecular interactions. Together with the fact that spermidine facilitates late stages of α-Syn aggregation, our data demonstrate that spermidine promotes the very early stages of protein aggregation including α-Syn misfolding and dimerization. This finding suggests that increased levels of spermidine and potentially other polyamines can initiate the disease-related process of α-Syn.
Assessment of genomic relationship between Oryza sativa and Oryza australinesis
FM Abbasi, H Ahmad, F Perveen, M Inamullah, M Sajid, DS Brar
African Journal of Biotechnology , 2010,
Abstract: The genomic relationship between Oryza sativa (2n = 24 AA) and Oryza australinesis (2n = 24 EE) has not been established. Genomic relationship between these two species was assessed by using three strategies: genomic in situ hybridization (GISH), meiotic chromosome pairing, pollen and spikelet sterility. The hybrid was produced between these two species at the International Rice Research Institute using embryo rescue technique. The chromosome pairing was examined in pollen mother cells of O. australinesis, O. sativa and the hybrid between O. sativa and O. australinesis. The hybrid was highly sterile with pollen stain ability being 0.05%. Both parents showed regular meiosis with normal chromosome pairing. The F1 hybrid exhibited limited chromosome pairing. On an average, 0 - 4 bivalents and 16 - 24 univalents were recorded at metaphase-1. The most frequent configuration was two bivalent and twenty univalent. The chromosomes of O. australiensis appeared larger and darkly stained. For genomic in situ hybridization, genomic DNA from O. australiensis was used as probe for the mitotic and meiotic chromosomes of the hybrid between O. sativa and O. australiensis. GISH revealed unequivocal discrimination of O. australiensis chromosomes that appeared yellow due to hybridization signal from O. sativa chromosomes that fluoresced red due to counterstaining with propidium iodide (PI). No cross hybridization was examined between the labeled genomic DNA of O. australiensis and the chromosomes of O. sativa. The paired chromosomes were discriminated as autosyndetic and allosyndetic pairing. Meiotic and mitotic chromosomes of the O. australiensis and O. sativa, in the hybrid were discriminated by GISH for the first time. Results showed that both genomes were highly divergent.
Oryza Wild Species: An Alternative for Rice Breeding under Abiotic Stress Conditions  [PDF]
Vinícius Jardel Szareski, Ivan Ricardo Carvalho, Tiago Corazza da Rosa, Simone Morgan Dellagostin, Alan Junior de Pelegrin, Mauricio Horbach Barbosa, Osmarino Pires dos Santos, Dionei Schmidt Muraro, Velci Queiróz de Souza, Tiago Pedó, Tiago Zanatta Aumonde, Camila Pegoraro
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.96083
Abstract: Rice (Oryza sativa L.) presents a strategic role in social and economic levels. The aim of this study was to elucidate the presence of genetic variability for the genus Oryza, and the possibility of using genotypes with wild characteristics in rice breeding programs. The Oryza genus shows great genetic variability through wild genotypes available in the most varied environments around the world. The negative effects imposed by abiotic stresses such as flood, salinity, low temperatures, water deficiency and high temperatures may be minimized by the efficient identification of a genetic variability source from the Oryza genus. Among the main wild species presented by the Oryza genus, Oryza glumaepatula stands out being an active source of germplasm. The occurrence and preservation of genetic variability of Oryza genus is indispensable to obtain new rice genotypes, to guarantee food security for the human population, as well as to develop genotypes that adapt to climatic changes and natural adversities.
Genomic affinity between Oryza sativa and Oryza brachyantha as revealed by in situ hybridization and chromosome pairing
FM Abbasi, AH Shah, F Perveen, M Afzal, M Sajid, R Masood, F Nawaz
African Journal of Biotechnology , 2010,
Abstract: Genomic affinity between Oryza sativa (2n = 24 AA), and Oryza brachyantha (2n = 24 FF) was assessed by using three strategies: genomic in situ hybridization (GISH), meiotic chromosome pairing, pollen and spikelet sterility. The chromosome pairing was examined in pollen mother cells of O. brachyantha, O.sativa and the hybrid between O. sativa and O. brachyantha. The hybrid was highly sterile with no pollen stain ability. Both parents showed regular meiosis with normal chromosome pairing. The F1 hybrid exhibited limited chromosome pairing. On an average, 0-2 bivalents and 20-24 univalents were recorded at metaphase-1 and 0 - 1 univalent at diakinesis. The most frequent configuration was two bivalents and twenty univalent. The meiosis was highly irregular showing unequal distribution of chromosomes at anaphase, formation of multipolar bodies and variation in the cell cycle of both genomes. GISH revealed unequivocal discrimination of O. brachyantha chromosomes as appeared red from O. sativa chromosomes that fluoresced yellow. No cross hybridization was examined between the labeled genomic DNA of O. brachyantha and the chromosomes of O. sativa. Mitotic chromosomes of O. brachyantha and O. sativa, in the hybrid, were discriminated by GISH. High sterility in this hybrid could be due to abnormal meiosis and lack of pairing.
Analyses of karyotypes and comparative physical locations of the resistance gene, Xa-5, between Oryza sativa and Oryza,/i> officinalis
L Hong, C Yan, L Gang, L Xue-qun, Q Rui
African Journal of Biotechnology , 2009,
Abstract: A rice BAC library is being used widely in rice genome researches due to its distinctive advantages over other library systems. Physical locations of the rice bacterial blight resistance gene, Xa-5, was mapped comparatively with a BAC clone linked to this gene, in Oryza sativa, a cultivated rice and Oryza officinalis, a wild rice. Xa-5 was in situ hybridized to O. sativa and O. officinalis chromosomes. Xa-5 was located on the short arm of chromosome 5 in O. sativa but on the long arm of chromosome 5 in O.officinalis with fraction length (FL) 48.85 and 47.30%, respectively and their FL were consistent with the results obtained by using the selective marker of rice, RG556, as a probe. The frequencies of signal detection of the marker, RG556 and the BAC clone, 44B4, were 8.0 and 41.3% in O. sativa, while 9.0 and 42.3% in O. officinalis, respectively. Based on a comparative RFLP map of a wild rice, O. officinalis and O. sativa, comparative analyses of karyotypes of O. officinalis were demonstrated firstly by fluorescent in situ hybridization (FISH) using a BAC clone and an RFLP marker from O. sativa as probes.
Expression of RNA polymerase IV and V in Oryza sativa
Moo,Leydi de Rocio Canche; González,Angela Kú; Rodríguez-Zapata,Luis Carlos; Suarez,Victor; Casta?o,Enrique;
Electronic Journal of Biotechnology , 2012,
Abstract: rna polymerase iv and v are principal players in the rddm pathway, where their current study has shown interaction of several factors that control dna silencing of intergenic regions and sirna production. dna silencing is an important process during cell differentiation, nuclear structure and viral control. however, rna pol iv and v are yet to be study in model monocot systems like oryza sativa that can provide further information on genetic silence mechanism in plats. we show the expression pattern of these polymerases in tissues extracts of oryza sativa. detectable amounts of these polymerases are found in specific adult plant tissues and particularly expressed during somatic embryogenesis but not during early stages of normal embryo development. the use of synthetic auxin leads to an induction of both rna pol iv and v in scutellum tissue where nuclear localization may be required for genome reorganization and gene silencing.
The pulling force of a single DNA molecule condensed by spermidine  [PDF]
R. Zhang,B. I. Shklovskii
Quantitative Biology , 2003, DOI: 10.1016/j.physa.2004.11.013
Abstract: In a recent experiment, a single DNA double helix is stretched and relaxed in the presence of spermidine, a short positive polyelectrolyte, and the pulling force is measured as a function of DNA extension. In a certain range of spermidine concentration, a force plateau appears whose value shows maximum as a function of spermidine concentration. We present a quantitative theory of this plateau force based on the theory of reentrant condensation and derive almost parabolic behavior of the plateau force as a function of the logarithm of the spermidine concentration in the range of condensation. Our result is in good agreement with experimental data.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.