416 research outputs found
Editorial: Recent insights into the double role of hydrogen peroxide in plants
No full textReactive oxygen species (ROS) of varied types can be yielded in plants at several primary sites (such as the chloroplast, mitochondria, and peroxisomes) under normal aerobic metabolism via processes including photosynthetic and respiratory electron transport chains. However, impaired oxidant-antioxidant balance and extreme growth conditions in plants are bound to cause increases in the cellular concentrations of radical and non-radical ROS such as superoxide anions (O2•−), hydroxyl radical (OH•), singlet oxygen (1O2), and hydrogen peroxide (H2O2). On the one hand, H2O2 has no unpaired electrons and is moderately reactive. Owing to its relative stability compared to other ROS and its capacity for diffusing through aquaporins in the membranes and over more considerable distances within the cell (Bienert et al., 2007), H2O2 acts as a stress signal transducer
and contributes to numerous physiological functions in plants. On the other hand, H2O2 is a relatively long-lived molecule with a half-life of 1 ms, readily crosses biological membranes, and consequently can bring oxidative consequences far from the site of its formation (Neill et al., 2002; Sharma et al., 2012; Sehar et al., 2021). The Frontiers Research Topic “Recent Insights into the Double Role of Hydrogen Peroxide in Plants” highlighted the major mechanisms underlying the dual role of H2O2 in response to different abiotic stresses in plants. This Research Topic incorporated 19 publications, including 10 original research articles, 8 reviews, and one perspective article
Diaphyseal tibiofibular synostosis in professional athletes: Report of 2 cases
No full textAnterior leg pain is common in professional athletes and tibiofibular synostosis is reported to be a rare cause of anterior compartment pain or ankle pain related to sports activities. The management and appropriate treatment of this condition in professional athletes is controversial and the literature on the topic is sparse. Distal synostosis is usually related to ankle sprain and syndesmotic ligament injury, and proximal synostosis has been linked to leg length discrepancy and exostosis. Mid-shaft synostosis is even less common than proximal and distal forms. We present the treatment of mid-shaft tibiofibular synostosis in 2 cases of professional athletes (soccer and basketball player), along with a review of the literature. When diaphyseal synostosis is diagnosed, first-line conservative treatment, including ultrasound-guided steroid injection is recommended. However, if it does not respond to conservative management, surgical resection may be indicated to relieve symptoms
Synostose tibio-fibulaire diaphysaire chez l'athlète professionnel: À propos de deux cas
No full textLa synostose tibio-fibulaire a été décrite comme une cause rare de douleur antérieure de jambe ou decheville chez les athlètes. La prise en charge de ces synostoses est controversée et les données de lalittérature sont rares. Ces synostoses tibio-fibulaires peuvent être distales, proximales ou plus rarementdiaphysaires,. Nous présentons la prise en charge de deux synostoses diaphysaires survenues chez deuxathlètes professionnels (basket et football). Un traitement conservateur comprenant des injections destéroïdes sous échographie est recommandé dans un premier temps. Le traitement chirurgical peut êtreproposé en cas d’échec
Seamless subseasonal probabilistic streamflow forecasting: MuTHRE lets you have your cake and eat it too
No full textAbstract - Session HS4.6Abstract not availableMark Thyer, David McInerney, Dmitri Kavetski, Richard Laugesen, Fitsum Woldemeskel, Narendra Tuteja, and George Kuczer
Analysis of the Romanian Offer of ERP Solutions
No full textThis article tries to make an analysis of the actual Romanian offer of ERP (Enterprise Resource Planning) solutions. In the first part of the article the level of ERP adoption by Romanian companies having as main sources two studies published in 2006 about the ERP market in Romania, namely: "ERP Romania 2006" by Pierre Audoin Consultants (PAC) and the second one made by the media company Agora Media and the market research company Sensimark. In the second part of the article a comparative analysis of the first seven best placed ERP products on the Romanian market will be made. In order to accomplish this analysis a synthesized table has been included with all 7 products together with the analysis criteria grouped in three categories: function, technical characteristics, and market segment that it addresses.ERP, accounting software, ERP software provider
Cloning and sequencing of the γ-subunit of retinal cyclic-GMP phosphodiesterase from rd mouse
No full textMolecular cloning, sequencing and Northern blot analysis have been performed on the γ-subunit of cyclic-GMP phosphodiesterase (cGMP-PDE) from the retina of mice affected with the rd mutation. The full length cDNA has a total of 926 bp which include 261 bp of coding region, 121 bp of 5'-untranslated and 544 bp of 3'-untranslated regions. The latter contains a poly A tail of 50 bp. The coding region has only one base changed from the normal mouse cGMP-PDE cDNA, a C replaced by an A at position 105 Tuteja and Farber 1988, and 91% homology with the coding region of the bovine retinal enzyme Ovchinnikov et al 1986. The mRNA of cGMP-PDE is 900 bp long in both normal and rd mouse retinas and codes for a protein containing 87 amino acids. The deduced amino acid sequence of cGMP-PDEfrom rd retina has 100% homology with that of the enzyme from normal mouse retina and 97.7% homology with that of the bovine cGMP-PDE suggesting that if this subunit of cGMP-PDE is properly transcribed and translated, it is not defective in the degenerative rd mouse retina
The <i>Plasmodium</i> eukaryotic initiation factor-2α kinase IK2 controls the latency of sporozoites in the mosquito salivary glands
No full textSporozoites, the invasive form of malaria parasites transmitted by mosquitoes, are quiescent while in the insect salivary glands. Sporozoites only differentiate inside of the hepatocytes of the mammalian host. We show that sporozoite latency is an active process controlled by a eukaryotic initiation factor-2α (eIF2α) kinase (IK2) and a phosphatase. IK2 activity is dominant in salivary gland sporozoites, leading to an inhibition of translation and accumulation of stalled mRNAs into granules. When sporozoites are injected into the mammalian host, an eIF2α phosphatase removes the PO4 from eIF2α-P, and the repression of translation is alleviated to permit their transformation into liver stages. In IK2 knockout sporozoites, eIF2α is not phosphorylated and the parasites transform prematurely into liver stages and lose their infectivity. Thus, to complete their life cycle, Plasmodium sporozoites exploit the mechanism that regulates stress responses in eukaryotic cells
Plasmodium falciparum DNA helicase 60 is a schizont stage specific, bipolar and dual helicase stimulated by PKC phosphorylation
No full textThe fundamental biology and the biochemical processes at different developmental stages of the malaria parasite Plasmodium falciparum have not been explored in detail. As a step toward understanding the various mechanisms engaged in nucleic acid metabolism of this pathogen, particularly the essential enzymes involved in nucleic acid unwinding, recently, we have reported the isolation of the first P. falciparum DEAD-box DNA helicase 60 (PfDH60), which contained striking homology with p68 protein [Pradhan A, Chauhan VS, Tuteja R. A novel 'DEAD-box' DNA helicase from Plasmodium falciparum is homologous to p68. Mol Biochem Parasitol 2005;140:55-60]. In this study, we show novel important properties of PfDH60. Immunofluorescence assay studies revealed that the peak expression of PfDH60 is mainly in the schizont stages of the development of P. falciparum, where DNA replication is active. Interestingly, this is a bipolar DNA helicase, which unwinds dsDNA in both the directions. PfDH60 can also unwind RNA-DNA and RNA-RNA duplexes. PfDH60 is phosphorylated by protein kinase C at the Ser and Thr residues. The helicase and ATPase activities of PfDH60 were stimulated after this phosphorylation. The cell-cycle dependent expression, bipolar translocation and dual nature collectively suggest that PfDH60 may be involved in the process of DNA replication and distinct cellular processes in the parasite and this study should make an important contribution in our better understanding of DNA metabolic pathways such as repair, recombination and replication
Grain Legumes (Soybean, Chickpea, and Peanut): Omics Approaches to Enhance Abiotic Stress Tolerance
No full textLegumes rank third in world crop production, and abiotic stress is the major
constraint to crop productivity. Biotechnological applications including all "omics"
have been the direct and potential approaches for improving abiotic stress tolerance
in grain legumes and requires knowledge of stress response at molecular level, which
includes gene expression to protein or metabolite and its phenotypic effects.
Genome-wide expression profiling studies have been carried out in the legumes to
identify the candidate genes and regulatory networks among abiotic stress responses.
Among the grain legumes, although soybean has been more intensively studied,
more recently, sensitive and tolerant varieties of chickpea and peanut have been
characterized under abiotic stress conditions. Nevertheless, proteomic studies in
response to abiotic stress in legumes are still very limited with only Medicago
truncatula and soybean protein reference maps available. Some of the major QTL
controlling abiotic stress tolerance in legumes have been mapped for a major QTL for
salt tolerance in soybean and drought tolerance-related traits in peanut. Although,
Agrobacterium-mediated gene transfer has been reported in all the major legume
crops, so far only one legume, that is, soybean, has been commercialized. Transgenic
technologies for improved abiotic stress tolerance involving regulatory genes have
proved more efficient than using single or multiple functional genes involved in
stress tolerance..
Rules for the Design of Patchy Particles using Self-Assembled Monolayers.
No full textThis thesis centers on the design of patchy particles and their self-assembly into ordered structures. Patchy particles have a patterned surface consisting of sticky and repulsive patches. These patches can be exploited to arrange the particles into ordered structures. In this thesis, the patchy particles are formed using monolayer protected metal nanoparticles (MPMNPs) consisting of a gold substrate coated by a self-assembled monolayer (SAMs) of thiol surfactants. The structure and patterning of the SAM can be controlled by tuning parameters like NP size and monolayer composition (variable number of surfactants in the monolayer with different length, immiscibility, and concentration). The patterned monolayer governs the interactions of the nanoparticle (NP) with its environment and other NPs. Binary SAMs were previously studied in the Glotzer group through molecular simulations. It was found that the MPMNPs could form Janus and striped particles based on sufficient entropic gains at the interfaces between immiscible surfactants.
Coarse-grained simulations performed in this study have added additional surfactants to the monolayer to find a variety of new patterns (decorated Janus, decorated Cerberus, Neapolitan, decorated stripes, alternating stripes and tetrahedral particles to name a few). These patterns can be further modified by changing the ordering of the surfactants, adding additional patchiness, or changing the coverage of the patches.
This work also introduces a new way of producing small Janus NP by using SAMs of surfactants with equal end groups but sufficient length difference. The long surfactants tend to crystallize on the surface of the NP leading to macrophase separation. These Janus NPs can be further functionalized to form dimers and other interesting structures. The molecular dynamics results obtained in this study are in good agreement with experimental observations.
Finally, ordered structures obtained using patterned MPMNPs are also studied. Ordering of binary MPMNPs has been observed experimentally, and this study reproduces this behavior through computer simulations and extrapolates the findings to other mixed SAMs patterns.PhDChemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/98044/1/inespons_1.pd
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