Relation of locus of control and creativity with learning styles

The current paper aimed to investigate the relation between the locus of control and creativity with learning styles among the third grade high school students in the city of Kamyaran. The universe under study in this research consisted of all third grade high school students of the city of Kamyaran. The statistical population included 300 third grade students who were chosen by the cluster sampling method. Tools for collecting data involved the Abedi's creativity questionnaire (1993), Rotter's internal and external locus of control scale (1996) and the Kolb's learning styles questionnaire (1971). To analyze the data, the independent groups t test, one-way variance analysis (ANOVA), the simple Pearson correlation and the multivariate variance analysis (MANOVA) were sued. Results indicated that there was a difference between students and the internal and external locus of control in terms of various learning styles (P<0/03), and also there was a difference between the students with the various learning styles and the creativity level (P<0/01). Findings also suggested that there was a significant difference between the internal and external locus of control with the creativity and gender, and also there was not a significant difference between learning styles and gender

Cryo-EM of a heterogeneous biochemical fraction elucidates multiple protein complexes from a multicellular thermophilic eukaryote

Biomolecular complexes and their interactions govern cellular structure and function. Understanding their architecture is a prerequisite for dissecting the cell's inner workings, but their higher-order assembly is often transient and challenging for structural analysis. Here, we performed cryo-EM on a single, highly heterogeneous biochemical fraction derived from Chaetomium thermophilum cell extracts to visualize the biomolecular content of the multicellular eukaryote. After cryo-EM single-particle image processing, results showed that a simultaneous three-dimensional structural characterization of multiple chemically diverse biomacromolecules is feasible. Namely, the thermophilic, eukaryotic complexes of (a) ATP citrate-lyase, (b) Hsp90, (c) 20S proteasome, (d) Hsp60 and (e) UDP-glucose pyrophosphorylase were characterized. In total, all five complexes have been structurally dissected in a thermophilic eukaryote in a total imaged sample area of 190.64 μm2, and two, in particular, 20S proteasome and Hsp60, exhibit side-chain resolution features. The C. thermophilum Hsp60 near-atomic model was resolved at 3.46 Å (FSC = 0.143) and shows a hinge-like conformational change of its equatorial domain, highly similar to the one previously shown for its bacterial orthologue, GroEL. This work demonstrates that cryo-EM of cell extracts will greatly accelerate the structural analysis of cellular complexes and provide unprecedented opportunities to annotate architectures of biomolecules in a holistic approach

Identification of clinically antibiotic resistant genes Aac(3)-IIa and Aac(6’)-Ib in wastewater samples by multiplex PCR

Background: Aminoglycoside antibiotics are widely used in medical centers, particularly to treat infections. The resistance developed against these agents is a huge concern in health care. A number of researchers have reported that hospital and municipal wastewaters are among the most important dissemination sources of these agent into the environment. Some, however, do not agree with this opinion. In the present study, the prevalence of aminoglycoside resistance genes was investigated in raw and effluent wastewater from hospital and municipal wastewater treatment plants. Methods: To conduct this descriptive-analytical study, 30 samples were taken according to sampling principles and cold cycle and transferred to the molecular laboratory. DNA was extracted by the freeze-thaw method using a kit (Promega). The genes aac(3)-IIa and aac(6’)-Ib which code aminoglycoside resistance were examined in this study. Results: The results indicated that the studied genes are present in 35% of urban and hospital wastewaters, and their frequency percentage is higher in hospital wastewater (52%) than urban wastewater (48%). The studied genes were identified in 61% of raw hospital wastewater samples; however, they were not detected in the output wastewater from the studied treatment plants. Conclusion: Although, the studied genes were not detected in the final effluent, there is a high potential for their release into the environment. The current study demonstrated that the coding genes of aminoglycoside antibiotic resistance are present in raw urban and hospital wastewaters. In the case of improper exploitation of wastewater treatment plants, the output water can contaminate other environmental sections, such as soil and water resources, and result in the emission of these contaminants

Cryo-EM structure of the SEA complex

The SEA complex (SEAC) is a growth regulator that acts as a GTPase-activating protein (GAP) towards Gtr1, a Rag GTPase that relays nutrient status to the Target of Rapamycin Complex 1 (TORC1) in yeast 1 . Functionally, the SEAC has been divided into two subcomplexes: SEACIT, which has GAP activity and inhibits TORC1, and SEACAT, which regulates SEACIT 2 . This system is conserved in mammals: the GATOR complex, consisting of GATOR1 (SEACIT) and GATOR2 (SEACAT), transmits amino acid 3 and glucose 4 signals to mTORC1. Despite its importance, the structure of SEAC/GATOR, and thus molecular understanding of its function, is lacking. Here, we solve the cryo-EM structure of the native eight-subunit SEAC. The SEAC has a modular structure in which a COPII-like cage corresponding to SEACAT binds two flexible wings, which correspond to SEACIT. The wings are tethered to the core via Sea3, which forms part of both modules. The GAP mechanism of GATOR1 is conserved in SEACIT, and GAP activity is unaffected by SEACAT in vitro. In vivo, the wings are essential for recruitment of the SEAC to the vacuole, primarily via the EGO complex. Our results indicate that rather than being a direct inhibitor of SEACIT, SEACAT acts as a scaffold for the binding of TORC1 regulators.</p

Encapsulation of cannabidiol in oil-in-water nanoemulsions and nanoemulsion-filled hydrogels: A structure and biological assessment study

Hypothesis: Lipophilic cannabidiol can be solubilized in oil-in water nanoemulsions, which can then be impregnated into chitosan hydrogels forming another colloidal system that will facilitate cannabidiol's release. The delivery from both systems was compared, alongside structural and biological studies, to clarify the effect of the two carriers' structure on the release and toxicity of the systems. Experiments: Oil-in-water nanoemulsions (NEs) and the respective nanoemulsion-filled chitosan hydrogels (NE/HGs) were formulated as carriers of cannabidiol (CBD). Size, polydispersity and stability of the NEs were evaluated and then membrane dynamics, shape and structure of both systems were investigated with EPR spin probing, SAXS and microscopy. Biocompatibility of the colloidal delivery systems was evaluated through cytotoxicity tests over normal human skin fibroblasts. An ex vivo permeation protocol using porcine ear skin was implemented to assess the release of CBD and its penetration through the skin. Findings: Incorporation of the NEs in chitosan hydrogels does not significantly affect their structural properties as evidenced through SAXS, EPR and confocal microscopy. These findings indicate the successful development of a novel nanocarrier that preserves the NE structure with the CBD remaining encapsulated in the oil core while providing new rheological properties advantageous over NEs. Moreover, NE/HGs proved to be more efficient as a carrier for the release of CBD. Cell viability assessment revealed high biocompatibility of the proposed colloids

2.7 Å cryo-EM structure of vitrified M. Musculus H-chain apoferritin from a compact 200 keV cryo-microscope

Here we present the structure of mouse H-chain apoferritin at 2.7 Å (FSC = 0.143) solved by single particle cryogenic electron microscopy (cryo-EM) using a 200 kV device, the Thermo Fisher Glacios®. This is a compact, two-lens illumination system with a constant power objective lens, without any energy filters or aberration correctors, often thought of as a "screening cryo-microscope". Coulomb potential maps reveal clear densities for main chain carbonyl oxygens, residue side chains (including alternative conformations) and bound solvent molecules. We used a quasi-crystallographic reciprocal space approach to fit model coordinates to the experimental cryo-EM map. We argue that the advantages offered by (a) the high electronic and mechanical stability of the microscope, (b) the high emission stability and low beam energy spread of the high brightness Field Emission Gun (X-FEG), (c) direct electron detection technology and (d) particle-based Contrast Transfer Function (CTF) refinement have contributed to achieving high resolution. Overall, we show that basic electron optical settings for automated cryo-electron microscopy imaging can be used to determine structures approaching atomic resolution

Osmotic stress response in BetP: How lipids and K+ team up to overcome downregulation

The trimeric betaine symporter BetP senses an osmotic upshift via its osmosensory C-terminal domain and responds rapidly with a steep increase in transport rate. Full activation requires both an elevated internal K+ concentration and a yet unknown membrane stimulus. Moreover, the molecular mechanisms of stress sensing and upregulation remain unclear. Here, we show that K+ binding to BetP in vivo is highly cooperative. Using X-ray crystallography, we identify four putative K+ interaction sites at the C-terminal domains of BetP. Single particle CryoEM on BetP reconstituted in amphipols (AMP-BetP), in the absence of K+, revealed that the three C-terminal domains are oriented symmetrically near the membrane surface, representing a new downregulated state. The presence of K+ resulted in asymmetric partial unfolding of the C-terminal domains, which was assigned as an intermediate between the downregulated state and the conformation observed in crystal structures. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy in 2D crystals of BetP reveal glutamate/aspartate and tyrosine responses to K+, in agreement with the identified K+ interaction sites, as well as specific unfolding events in the C-terminal domain upon activation. A rearrangement of the relative protomer orientations confers upregulation through key structural elements involved in the alternating access of BetP affecting sodium and betaine binding affinities. Although K+-specific regulation is unique to BetP we discuss unfolding/refolding of sensory domains as a unifying element in hyperosmotic stress response of osmoregulated transporters.Competing Interest StatementThe authors have declared no competing interest

Cryo-Electron Microscopy Snapshots of Eukaryotic Membrane Proteins in Native Lipid-Bilayer Nanodiscs

New technologies for purifying membrane-bound protein complexes in combination with cryo-electron microscopy (EM) have recently allowed the exploration of such complexes under near-native conditions. In particular, polymer-encapsulated nanodiscs enable the study of membrane proteins at high resolution while retaining protein–protein and protein–lipid interactions within a lipid bilayer. However, this powerful technology has not been exploited to address the important question of how endogenousas opposed to overexpressedmembrane proteins are organized within a lipid environment. In this work, we demonstrate that biochemical enrichment protocols for native membrane–protein complexes from Chaetomium thermophilum in combination with polymer-based lipid-bilayer nanodiscs provide a substantial improvement in the quality of recovered endogenous membrane–protein complexes. Mass spectrometry results revealed ∼1123 proteins, while multiple 2D class averages and two 3D reconstructions from cryo-EM data furnished prominent structural signatures. This integrated methodological approach to enriching endogenous membrane–protein complexes provides unprecedented opportunities for a deeper understanding of eukaryotic membrane proteomes