3,109 research outputs found
Regulation of the Adrenal Cortex Function During Stress
A proposal to study the function of the adrenal gland in the rat during stress is presented. In the proposed project, three different phases of experimentation will be undertaken. The first phase includes establishment of the circadian rhythm of both brain amines and glucocoticoids, under normal conditions and under chronic and acute stressful conditions. The second phase includes the study of the pharmacokinetics of glucocorticoid binding under normal and stress conditions. The third phase includes brain uptake and binding under different experimental conditions. In the outlined experiments brain biogenic amines will be evaluated, adrenal functions will be measured and stress effect on those parameters will be studied. It is hoped that this investigation can explain some of the complex relationships between the brain neurotransmitter and adrenal function
In Silico Investigation of the Binding of MCoTI-II Plant Defense Knottin to the γ-NGF Serine Protease of the 7S Nerve Growth Factor Complex and Biological Activity of Its NGF Mimetic Properties
Copyright © 2019 American Chemical Society. Nerve growth factor (NGF) is an endogenously produced polypeptide that promotes the differentiation, survival, and repair of neurons in the central and peripheral nervous systems. While trophic proteins hold promise for the treatment of neuronal injury and disease, use of NGF is limited by its large molecular weight, lack of permeability through the blood-brain barrier, and peripheral side effects. Previously, we found that an extract of the Momordica cochinchinensis seed stimulated PC-12 neurite outgrowth. Bioactivity-guided fractioning of the seed extract suggested that the NGF mimetic agent was one of few defined proteins from this plant: one group being the defense Knottins and the other group of the lowest mass is the potent trypsin inhibitor MCoTI-II. Here, the NGF mimetic potential of this latter protein was investigated using two concurrent but different approaches. A biological study used recombinant purified MCoTI-II, which when tested in rat PC-12 cells grown on collagen, failed to initiate outgrowth relative to the positive control 7S NGF. In a separate computational study, the possibility was investigated such that MCoTI-II could exert an effect through binding to the serine protease γ-NGF subunit of the 7S NGF complex, analogous to its binding to its native receptor trypsin. Molecular dynamics simulations showed that MCoTI-II can bind stably to γ-NGF for >350 ns. Modeling indicated that this interaction could sterically inhibit 7S NGF complex formation, potentially altering the equilibrium between inactive complexed and free active NFG protein. In conclusion, the biological study now excludes the MCoTI-II protein as the NGF mimetic factor in the Momordica extract, an important and required step to identify the active component in this seed. On the other hand, the theoretical study has revealed a novel observation that may be of use in the development of strategies to affect NGF activity
PREPARATION AND EVALUATION OF ANTHRALIN BIODEGRADABLE NANOPARTICLES AS A POTENTIAL DELIVERY SYSTEM FOR THE TREATMENT OF PSORIASIS
Objective: Anthralin is one of the most effective drugs in psoriasis management. However, its side effects and unfavourable physicochemical properties limit its clinical use. Therefore, the objective of this study was to prepare and evaluate poly (ethylene glycol)-block-poly (ε-caprolactone) (PEG-b-PCL) nanoparticles as a potential delivery system for anthralin.Methods: PEG-b-PCL nanoparticles were prepared by the co-solvent evaporation method and evaluated using a variety of techniques. The effect of drug/polymer weight feed ratio on the nanoparticle size, drug loading capacity and encapsulation efficiency were studied. Drug release kinetics were studied using the dialysis bag method. Nanoparticle size was measured using dynamic light scattering and confirmed by transmission electron microscopy measurements.Results: PEG-b-PCL formed spherical nanoparticles having a diameter of 40 to 80 nm based on the polymer and level of drug loading. The size observed by TEM measurements was slightly smaller than that obtained by DLS due nanoparticle dryness during measurement. Drug loading capacity increased with increasing the drug/polymer ratio and a maximum loading of ~25% was obtained. Anthralin encapsulation in the nano particles resulted in ~120-fold increase in its aqueous solubility. Anthralin was released from the nanoparticles over a prolonged period of time where ~ 45% was released in 48 h.Conclusion: These results confirm the utility of PEG-b-PCL nanoparticles in enhancing the aqueous solubility and sustaining the release of athralin. Therefore, they might be used as a potential delivery system for the treatment of psoriasis.Â
Phylogenetic relationships within and among Brassica species from RAPD loci associated with blackleg resistance
The genus Brassica comprises economically important oilseed and vegetable crops. Their susceptibility to fungal diseases such as blackleg causes yield loss. In this study, thirty accessionsfrom USDA germplasm collection representing two diploid Brassica species (Brassica rapa and Brassica oleracea var. virids) and fifteen tetraploid cultivars (Brassica napus) from the national wintercanola variety trials (NWCVT) were evaluated using 13 sets of random amplified polymorphic DNA (RAPD) associated with blackleg resistance in Brassica nigra. 126 highly polymorphic bands with an average of 10 per primer were detected. A UPGMA dendrogram showed B. rapa as highly diverse and was supported from three different basal branches, while B. napus accessions were generally monophyletic. Similarly, all of B. oleraceae accessions were supported from the same basal node.Generally, the three species were reciprocally paraphyletic, suggesting that the RAPD markers showed both functional relationships as well as homology, possibly due to selection at the RAPD loci associated with blackleg resistance. Consequently, two potentially susceptible B. napus accessions were identified. The high polymorphic information content (PIC) and number of phylogenetically informative bands established RAPD as a useful tool for phylogenetic reconstruction, quantification ofgenetic diversity for conservation, cultivar classification and molecular breeding in Brassica
RAPD markers associated with resistance to blackleg disease in Brassica species
Blackleg, caused by Leptosphaeria maculans, is a serious disease of Brassica species. Genetic analysis of resistance to L. maculans was carried out with 15 accessions from the USDA Brassica germplasm collections, representing diploids (A, C), and tetraploid (AC) genomes, respectively; and 9 cultivars from the National Winter Canola Variety Trials (NWCVT) all carrying AC genomes. All genotypes were screened for blackleg disease at the cotyledonary stage. The results indicated that 46% of the 24 genotypes were resistant, while 54% were susceptible. On the other hand, adult plant screening revealed that all the public genotypes were resistant. In an effort to identify molecularmarkers associated with resistance to blackleg disease, all genotypes were screened with 13 RAPD and 8 SSR markers producing 169 amplified products. Six RAPD markers (OPB01, OPE03, OPE16, OPF10, OPE12, and OPI01) were polymorphic, while the SSR markers were monomorphic. Chi-square analysis indicated that 5 amplified fragments (OPE03-4000, OPE16-1100, OPE16-1300, OPE16-1900, and OPI01- 280) from RAPD primers were significantly associated with blackleg resistance. Thus this study demonstrated that RAPD primers could be effectively used to identify DNA markers that are associatedwith blackleg disease resistance, and that resistance to L. maculans might also exist in the A and C genomes
Detecting shielded explosives by coupling prompt gamma neutron activation analysis and deep neural networks
Prompt Gamma Neutron Activation Analysis is a nuclear-based technique that can be used in explosives detection. It relies on bombarding unknown samples with neutrons emitted from a neutron source. These neutrons interact with the sample nuclei emitting the gamma spectrum with peaks at specific energies, which are considered a fingerprint for the sample composition. Analyzing these peaks heights will give information about the unknown sample material composition. Shielding the sample from gamma rays or neutrons will affect the gamma spectrum obtained to be analyzed, providing a false indication about the sample constituents, especially when the shield is unknown. Here we show how using deep neural networks can solve the shielding drawback associated with the prompt gamma neutron activation analysis technique in explosives detection. We found that the introduced end-to-end framework was capable of differentiating between explosive and non-explosive hydrocarbons with accuracy of 95% for the previously included explosives in the model development data set. It was also, capable of generalizing with accuracy 80% over the explosives which were not included in the model development data set. Our results show that coupling prompt gamma neutron activation analysis with deep neural networks has a good potential for high accuracy explosives detection regardless of the shield presence
Nuclear ribosomal DNA diversity of a cotton pest (Rotylenchulus reniformis) in the United States
The reniform nematode (Rotylenchulus reniformis) has emerged as a major cotton pest in the United States. A recent analysis of over 20 amphimictic populations of this pest from the US and three othercountries has shown no sequence variation at the nuclear ribosomal internal transcribed spacer (ITS) despite the region’s usual variability. We investigated this unexpected outcome by amplifying, cloningand sequencing two regions of the nuclear ribosomal DNA (18S, ITS1) to ascertain whether any variation occurred within and among populations of reniform nematodes in Alabama, US. Both thenrITS1 and the relatively conserved 18S region showed a fairly substantial amount of variation among populations. The identity among ITS sequences ranged from 1.00 to 0.86, while sequence identity at the18S ranged from 1.00 to 0.948. We conclude that variation does exist in these sequences in reniform nematodes, and the earlier report showing no ribosomal ITS variation in this pest might have beencaused by preferential amplification of a conserved ITS paralog. Current and future application towards resistance in cotton varieties to this pest requires reliable information on the molecular variability of thenematode in cotton-growing areas
Super-resolution imaging reveals the sub-diffraction phenotype of Zellweger Syndrome ghosts and wild-type peroxisomes.
Peroxisomes are ubiquitous cell organelles involved in many metabolic and signaling functions. Their assembly requires peroxins, encoded by PEX genes. Mutations in PEX genes are the cause of Zellweger Syndrome spectrum (ZSS), a heterogeneous group of peroxisomal biogenesis disorders (PBD). The size and morphological features of peroxisomes are below the diffraction limit of light, which makes them attractive for super-resolution imaging. We applied Stimulated Emission Depletion (STED) microscopy to study the morphology of human peroxisomes and peroxisomal protein localization in human controls and ZSS patients. We defined the peroxisome morphology in healthy skin fibroblasts and the sub-diffraction phenotype of residual peroxisomal structures ('ghosts') in ZSS patients that revealed a relation between mutation severity and clinical phenotype. Further, we investigated the 70 kDa peroxisomal membrane protein (PMP70) abundance in relationship to the ZSS sub-diffraction phenotype. This work improves the morphological definition of peroxisomes. It expands current knowledge about peroxisome biogenesis and ZSS pathoethiology to the sub-diffraction phenotype including key peroxins and the characteristics of ghost peroxisomes
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