Investigation of HIV-1 Gag binding with RNAs and Lipids using Atomic Force Microscopy

Atomic Force Microscopy was utilized to study the morphology of Gag, {\Psi}RNA, and their binding complexes with lipids in a solution environment with 0.1{\AA} vertical and 1nm lateral resolution. TARpolyA RNA was used as a RNA control. The lipid used was phospha-tidylinositol-(4,5)-bisphosphate (PI(4,5)P2). The morphology of specific complexes Gag-{\Psi}RNA, Gag-TARpolyA RNA, Gag-PI(4,5)P2 and PI(4,5)P2-{\Psi}RNA-Gag were studied. They were imaged on either positively or negatively charged mica substrates depending on the net charges carried. Gag and its complexes consist of monomers, dimers and tetramers, which was confirmed by gel electrophoresis. The addition of specific {\Psi}RNA to Gag is found to increase Gag multimerization. Non-specific TARpolyA RNA was found not to lead to an increase in Gag multimerization. The addition PI(4,5)P2 to Gag increases Gag multimerization, but to a lesser extent than {\Psi}RNA. When both {\Psi}RNA and PI(4,5)P2 are present Gag undergoes comformational changes and an even higher degree of multimerization

Evaluation of drought tolerance indices among some winter rapeseed cultivars

The main purpose of this study was to evaluate the effect of drought stress on seed yield of some winter rapeseed cultivars and to study relevant drought tolerance indices, along with identifying resistant cultivars to drought stress. Plant materials were sown in split plot arrangement based on a randomized complete blocks design, at Islamic Azad University of Tabriz research field. Three drought stress levels which include 80, 130, and 180 mm water evaporation from class A pan were considered as the main factor levels, while seven winter rapeseed cultivars which include Licord, Okapi, Opera, S.L.M.046, Zarfam, Modena, and Talaye were arranged to sub plots. Studied quantitative drought tolerance indices were, tolerance index (TOL), mean productivity (MP), stress susceptibility index (SSI), stress tolerance index (STI), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), and percentage of yield reduction (%Reduction). The yield stability analysis of the studied cultivars was done by GGE biplot method. According to the results derived from principal component analysis and regarding evaluation of correlation coefficients among indices, STI and GMP were selected as the two superior indices for identifying drought resistant cultivars. Three dimensional scatter plots based on STI and GMP indices showed that Licord and Talaye were the most suitable cultivars, and were situated in group, A. In addition, Modena and Zarfam were identified as sensitive and resistant to drought stress, respectively.Key words: Brassica napus L, principal component analysis, drought stress, drought tolerance indices, stability analysis (GGE biplot), 3D scatter plot

A novel minimal in vitro system for analyzing HIV-1 Gag mediated budding

A biomimetic minimalist model membrane was used to study the mechanism and kinetics of cell-free in vitro HIV-1 Gag budding from a giant unilamellar vesicle (GUV). Real time interaction of Gag, RNA and lipid leading to the formation of mini-vesicles was measured using confocal microscopy. Gag forms resolution limited punctae on the GUV lipid membrane. Introduction of the Gag and urea to a GUV solution containing RNA led to the budding of mini-vesicles on the inside surface of the GUV. The GUV diameter showed a linear decrease in time due to bud formation. Both bud formation and decrease in GUV size were proportional to Gag concentration. In the absence of RNA, addition of urea to GUVs incubated with Gag also resulted in subvesicle formation but exterior to the surface. These observations suggest the possibility that clustering of GAG proteins leads to membrane invagination even in the absence of host cell proteins. The method presented here is promising, and allows for systematic study of the dynamics of assembly of immature HIV and help classify the hierarchy of factors that impact the Gag protein initiated assembly of retroviruses such as HIV.Comment: 27 pages, 9 Figures and 0 Table

Bone health in patients with multiple sclerosis relapses

OBJECTIVES: To evaluate the bone health and vitamin D levels of a cohort of patients with relapses of multiple sclerosis (MS) and to propose an algorithm for the management of bone health in this patient group. METHODS: We prospectively studied 56 consecutive patients from our acute relapse clinic. 3 patients were excluded from analysis as they were not deemed to have experienced an acute MS relapse. Bone health was assessed with vitamin D levels and Dual Energy X-ray Absorptiometry (DEXA) scanning (10 patients failed to attend for DEXA). Statistical analyses were used to compare groups and identify predictive variables. A review of the literature led to a proposed management protocol. RESULTS: Pre-relapse the baseline EDSS was ≤6.5 in all subjects, and <4.0 in the majority (66%). Most received corticosteroids. 51% had low bone mineral density (BMD) as defined by a T-score less than −1.0 on DEXA scanning. Three were osteoporotic (T-score less than −2.5). Thirty one of fifty (62%) subjects were Vitamin D deficient (25(OH)D less than 50 nmol/L). A range of variables, including previous corticosteroid usage, were not significantly predictive of reduced BMD. CONCLUSIONS: There was a high frequency of both low BMD and Vitamin D deficiency in this cohort of relatively young and largely ambulatory patients experiencing MS relapses. Current tools, such as the WHO FRAX algorithm, are inadequate in assessing bone status and fracture risk in this patient group, predominantly as they are focused on older age groups. We propose a simple clinical management algorithm

pH-Responsive PVA-Based Nanofibers Containing GO Modified with Ag Nanoparticles: Physico-Chemical Characterization, Wound Dressing, and Drug Delivery

Site-specific drug delivery and carrying repairing agents for wound healing purposes can be achieved using the intertwined three-dimensional structure of nanofibers. This study aimed to optimize and fabricate poly (vinyl alcohol) (PVA)-graphene oxide (GO)-silver (Ag) nanofibers containing curcumin (CUR) using the electrospinning method for potential wound healing applications. Fourier Transform Infrared (FTIR) spectrophotometry, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), and zeta potential were used to characterize the nanostructures. The mechanical properties of the nanostructures were subsequently examined by tensile strength and elongation test. As shown by MIC analysis of E. coli and S. aureus bacteria, the fabricated nanofibers had superior inhibitory effects on the bacteria growth. Ag nanoparticles incorporation into the nanofibers resulted in increased loading and encapsulation efficiencies from 21% to 56% and from 61% to 86%, respectively. CUR release from PVA/GO-Ag-CUR nanofiber at pH 7.4 was prevented, while the acidic microenvironment (pH 5.4) increased the release of CUR from PVA/GO-Ag-CUR nanofiber, corroborating the pH-sensitivity of the nanofibers. Using the in vitro wound healing test on NIH 3T3 fibroblast cells, we observed accelerated growth and proliferation of cells cultured on PVA/GO-Ag-CUR nanofibers

Optimization of in vitro culture and transfection condition of bovine primary spermatogonial stem cells

The present study aimed to optimize the in vitro culture and transfection efficiency of bovine primary spermatogonial stem cells (SSCs). To this end, SSCs were obtained from newborn Holstein bull calves by two-step enzymatic digestion. After enrichment and culture, SSCs were characterized by using alkaline phosphatase (AP) staining and expression of vasa and thy1 genes as specific bovine SSC markers. To evaluate the effect of antioxidants on vitality, colony formation, and the expression of pro- and anti-apoptotic genes of bovine SSCs, various concentrations of vitamin C (5, 10, 25 and 50 μg/mL) and Trolox (a water soluble α-tocopherol analogue) (12.5, 25, 50 and 100 μg/mL) were added to the SSC culture medium. The results showed that SSCs treated with 50 μg/mL of vitamin C or 25 μg/mL of Trolox individually could increase cell viability and colony formation significantly in comparison with other concentrations and the control group. Additionally, the expressions of bax (as a pro-apoptotic gene) and bcl2 (as an anti-apoptotic gene) were significantly lower and higher than the control group, respectively. To optimize the transfection condition, the effective dosages of vitamin C or Trolox, with various concentrations of two transfection reagents (X-tremeGENE HP and Turbofect) and DNA, at day 8 of culture, were studied. Results showed that 1 μl X-tremeGENE HP or 0.5 μl Turbofect and 2 μg of DNA are the best concentrations for transfecting SSCs. However, X-tremeGENE HP expressed more potential for transfecting SSCs in comparison with Turbofect. Besides, no difference was observed between the use of defined doses of vitamin C or Trolox.Keywords: Apoptosis, gene transfer, primary cells, viability, vitamin C, Trolo

Population abundance of pomegranate aphid, Aphis punicae (Homoptera: Aphididae), predators in Southwest of Iran

Pomegranate aphid, Aphis punicae Passarini (Hom., Aphididae) is an important pest of pomegranate in Iran. Predators play critical role in natural control of the pest. In this study, seasonal population dynamics of the aphid predators were investigated during two years (2016/2017) in Ilam province, southwest of Iran. Samplings were bi-weekly performed in an experimental pomegranate orchard. Four insect predators, Coccinella septempunctata L., Oenopia congelobata L. (Col., Coccinellidae), Xanthogramma pedisseguum Haris (Dip., Syrphidae) and Chrysoperla carnea Stephens (Neu., Chryspidae) were identified as predators of A. punicae in Ilam. The natural enemies occurred during March to May in both years. The highest and the lowest densities were belong to X. pedisseguum and O. congelobata, respectively. Results of the study can be used for developing integrated pest management program of A. punicae in pomegranate orchards

Sulfated galactans from red seaweed Gracilaria fisheri target epidermal growth factor receptor (EGFR) and inhibit cholangiocarcinoma cells (CCA) proliferation

Cholangiocarcinoma (CCA) is increasing in incidence worldwide and is resistant to chemotherapeutic agents, making treatment of CCA a major challenge. Previous studies reported that natural sulfated polysaccharides (SPs) disrupted growth factor receptor activation in cancer cells. The present study, therefore, aimed at investigating the anti-proliferation effect of sulfated galactans (SG) isolated from the red seaweed Gracilaria fisheri (G. fisheri) on CCA cell lines. Direct binding activity of SG to CCA cells, epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) were determined. The effect of SG on proliferation of CCA cells was investigated. Cell cycle analyses and expression of signaling molecules associated with proliferation were also determined. The results demonstrated that SG bound directly to EGFR. SG inhibited proliferation of various CCA cell lines by inhibiting EGFR and extracellular signal-regulated kinases (ERK) phosphorylation, and inhibited EGF-induced increased cell proliferation. Cell cycle analyses showed that SG induced cell cycle arrest at the G0/G1 phase, down-regulated cell cycle genes and proteins (cyclin-D, cyclin-E, Cdk-4, Cdk-2), and up-regulated the tumor suppressor protein P53 and the cyclin-dependent kinase inhibitor P21. Taken together, these data demonstrate that SG from G. fisheri inhibited proliferation of CCA cells, and its mechanism of inhibition is mediated, to some extent, by inhibitory effects on EGFR activation and EGFR/ERK signaling pathway. SG presents a potential EGFR targeted molecule, which may be further clinically developed in a combination therapy for CCA treatment

Investigating factors affecting loyalty to learning through social media

Background and Objectives: Today, with the development of mass communication tools and computers, the penetration and expansion of the Internet in various areas of life is undeniable. One of the most pervasive phenomena that has emerged on the Internet in recent years is the emergence of social media. Social media has affected social and economic life. The spread of social media has attracted the attention of various segments of society, including educational administrators. From the perspective of educational administrators, social media provides unique opportunities for teaching and learning. Social media is a group of Internet-based applications that rely on the basics of Web technology to create and share user-generated content. Social media, in addition to the entertainment aspect, is used to access and disseminate learning information, and their use to achieve educational goals has been studied in detail. One of the applications of social media is learning, in which the learning process takes place through knowledge sharing. With the development of social media, proper and efficient use of it is inevitable. Social media is a good tool for learning. In order to have a better and more advanced society, special attention should be given to the role of learning through social media. One of the issues that promotes the development of learning through social media is the loyalty of users to learning through social media. Therefore, in the present study, the antecedents of learning loyalty through social media have been studied. Methods: The present study is a descriptive study in terms of objective and applied in nature. The data gathering instrument was a questionnaire and the population of this research was the users of the Telegram group of Qom IT Centre. In the current study, convenience sampling was used to collect 364 questionnaires. Data were analyzed using SPSS and LISREL software. Findings: The findings of the study showed that more than 95% of the statistical population were university educated and all the research hypotheses were confirmed. Conclusion: The results of the research show that two indicators for measurement of learning loyalty through social media (behavioral intention to continue using and willingness to recommend to others) are affected by satisfaction, and satisfaction is also affected by self-efficacy of learning and interest to learning through social media. The results also showed that the cognitive disability of the Internet has disadvantages and causes a decrease in self-efficacy and interest in learning through social media. When a person feels the self-efficacy of learning through social media, they find interest and satisfaction in learning through it. Also, the interest in learning through social media leads to the satisfaction of learning through it, and finally, if a person finds satisfaction in learning, they have a behavioral tendency to continue using social media and a tendency to advise others.Through the above, the development of social media as a learning tool is possible, and this brings many benefits, including reducing learning costs, reducing learning time, expanding learning fairly, and improving learning.   ===================================================================================== COPYRIGHTS  ©2020 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

Stochastic kinetics of viral capsid assembly based on detailed protein structures

We present a generic computational framework for the simulation of viral capsid assembly which is quantitative and specific. Starting from PDB files containing atomic coordinates, the algorithm builds a coarse grained description of protein oligomers based on graph rigidity. These reduced protein descriptions are used in an extended Gillespie algorithm to investigate the stochastic kinetics of the assembly process. The association rates are obtained from a diffusive Smoluchowski equation for rapid coagulation, modified to account for water shielding and protein structure. The dissociation rates are derived by interpreting the splitting of oligomers as a process of graph partitioning akin to the escape from a multidimensional well. This modular framework is quantitative yet computationally tractable, with a small number of physically motivated parameters. The methodology is illustrated using two different viruses which are shown to follow quantitatively different assembly pathways. We also show how in this model the quasi-stationary kinetics of assembly can be described as a Markovian cascading process in which only a few intermediates and a small proportion of pathways are present. The observed pathways and intermediates can be related a posteriori to structural and energetic properties of the capsid oligomers