Study of gene expression and steviol glycosides accumulation in Stevia rebaudiana Bertoni under various mannitol concentrations

Molecular Biology Reports - Stevia rebaudiana produces sweet steviol glycosides that are 300 times sweeter than sugar and have the beneficial effects on human health including anti-hyperglycaemic....     

Molecular Docking Analysis of 120 Potential HPV Therapeutic Epitopes Using a New Analytical Method

International Journal of Peptide Research and Therapeutics - The accurate modelling and scoring of protein–peptide (Pr–Pe) complexes are determining factors in the drug discovery...     

Prediction of shape and internal structure of the proximal femur using a modified level set method for structural topology optimisation

A computational framework was developed to simulate the bone remodelling process as a structural topology optimisation problem. The mathematical formulation of the Level Set technique was extended and then implemented into a coronal plane model of the proximal femur to simulate the remodelling of internal structure and external geometry of bone into the optimal state. Results indicated that the proposed approach could reasonably mimic the major geometrical and material features of the natural bone. Simulation of the internal bone remodelling on the typical gross shape of the proximal femur, resulted in a density distribution pattern with good consistency with that of the natural bone. When both external and internal bone remodelling were simulated simultaneously, the initial rectangular design domain with a regularly distributed mass reduced gradually to an optimal state with external shape and internal structure similar to those of the natural proximal femur.     

How Long Depends on How Fast—Perceived Flicker Dilates Subjective Duration

How do humans perceive the passage of time and the duration of events without a dedicated sensory system for timing? Previous studies have demonstrated that when a stimulus changes over time, its duration is subjectively dilated, indicating that duration judgments are based on the number of changes within an interval. In this study, we tested predictions derived from three different accounts describing the relation between a changing stimulus and its subjective duration as either based on (1) the objective rate of changes of the stimulus, (2) the perceived saliency of the changes, or (3) the neural energy expended in processing the stimulus. We used visual stimuli flickering at different frequencies (4–166 Hz) to study how the number of changes affects subjective duration. To this end, we assessed the subjective duration of these stimuli and measured participants'' behavioral flicker fusion threshold (the highest frequency perceived as flicker), as well as their threshold for a frequency-specific neural response to the flicker using EEG. We found that only consciously perceived flicker dilated perceived duration, such that a 2 s long stimulus flickering at 4 Hz was perceived as lasting as long as a 2.7 s steady stimulus. This effect was most pronounced at the slowest flicker frequencies, at which participants reported the most consistent flicker perception. Flicker frequencies higher than the flicker fusion threshold did not affect perceived duration at all, even if they evoked a significant frequency-specific neural response. In sum, our findings indicate that time perception in the peri-second range is driven by the subjective saliency of the stimulus'' temporal features rather than the objective rate of stimulus changes or the neural response to the changes.     

Protective effects of Cinnamomum verum,Cinnamomum cassia and cinnamaldehyde against 6-OHDA-induced apoptosis in PC12 cells

Cinnamon (Cinnamomum verum and C. cassia) is a medicinal plant, widely-used as a culinary spice. It possesses various therapeutic effects and can slow down the progression of neurological disorders impressively. In this article, the effects of hydro-alcohol extract and essential oil of C. verum and C. cassia and its main bioactive component cinnamaldehyde, has been examined on 6-OHDA-exposed PC12 cells as an in vitro model of Parkinson's disease. The cytotoxicity and cell apoptosis has been induced by 6-OHDA in PC12 cells. The protective effect was determined by measuring cell viability, the amount of reactive oxygen species (ROS), and apoptosis. Cell viability and apoptosis were assessed using resazurin assay, flow cytometry of propidium iodide (PI) stained cells, and western blot analysis. 6-OHDA resulted in the death and apoptosis of cells while, pretreatment with the extract and essential oil of C. verum and C. cassia at 20 µg/ml and cinnamaldehyde at 5 and 10 µM for 24 h could significantly increase the viability (p?<?0.001), and decrease ROS content (p?<?0.05). Pretreatment with the extracts increased survivin and decreased cyt-c whereas, pretreatment with the essential oil decreased cyt-c, increased survivin, and reduced P-p44/42/p44/42 levels to a level near that of the related control. The extract and essential oil of C. verum and C. cassia can be effective against 6-OHDA cytotoxicity. It is suggested that, the synergistic effects of cinnamaldehyde and other components of extract and essential oil promote cinnamon’s medicinal properties.

     

Hepatitis C virus genotypes in patients with chronic hepatitis C infection in southern Iran from 2016 to 2019

Hepatitis C is a liver disease caused by the hepatitis C virus (HCV). The treatment of HCV infection has become more complicated due to various genotypes and subtypes of HCV. The treatment of HCV has made significant advances with direct-acting antivirals. However, for the choice of medicine or the combination of drugs for hepatitis C, it is imperative to detect and discriminate the crucial HCV genotypes. The main objective of this study was to determine the pattern of circulating HCV genotypes in southern Iran, from 2016 until 2019. The other aim of the study was to determine possible associations of patients’ risk factors with HCV genotypes. A total of 803 serum samples were collected in 4 years (2016–2019) from patients with HCV antibody positive results. A total of 728 serum samples were HCV-RNA positive. The prevalence of HCV genotypes was detected using the genotype-specific RT-PCR test for serum samples obtained from 615 patients. The HCV genotype 1 (G1) was the most prevalent (48.8%) genotype in the area, with G1a, G1b, and mixed G1a/b representing 38.4%, 10.1%, and 0.3%, respectively. Genotype 3a was the next most prevalent (47.2%). Mixed genotypes 1a/3a were detected in 22 (3.6%) and finally G4 was found in 3 (0.5%) patients. The other HCV genotypes were not detected in any patient. Genotype 1 (1a and 1b alone, 1a/1b and 1a/3a coinfections) is the most prevalent HCV genotype in southern Iran. HCV G1 shows a significantly higher rate in people under 40 years old.     

Investigation of spore coat display of Bacillus subtilis β-galactosidase for developing of whole cell biocatalyst

The production of highly efficient, recyclable and cost-effective enzymes is one of the most important goals in industrial biotechnology. Bacterial spores are highly resistant to harsh environmental conditions, easy to produce and are suitable for manipulation of genetic materials. These features make them a very efficient tool for biotechnology. Here, we show the use bacterial spores for presentation of functional enzyme. Spore coat display was used to produce a biocatalyst, which expresses β-galactiosidase (LacA). This enzyme is commonly used to produce lactose-free milk for lactose intolerant individuals. The lacA gene from Bacillus subtilis strain 168 was expressed on the surface of B. subtilis RH101(ΔcotC) spores using CotC as protein carrier. Presence of LacA protein is verified by western blotting. Results of β-galactiosidase assay show that the expressed enzyme retained its activity in condition of freezing and drying, as well as after recovery from the reaction’s mixture.     

Comparative ontogeny of perfect and pistillate florets in Senecio vernalis (Asteraceae)

We studied the inflorescence, and in particular ontogeny and development of the florets in Senecio vernalis as a representative member of Asteraceae, using epi-illumination microscopy. Initiation and subsequent development of florets on the highly convex inflorescence apex occur acropetally, except for pistillate ray florets, which show a lag in initiation. Receptacular bracts derive from the receptacular surface after development of all florets. The order of whorl initiation in both disc and ray florets include corolla, androecium and finally the pappus, together with the gynoecium. Development of corolla lobes from a ring meristem occurs in bidirectional order starting from the lateral side, whereas stamens incept unidirectionally from the abaxial side. Concurrently with the inception of two median carpel primordia, a ring meristem develops at the base of the corolla from which pappus bristles differentiate in later stages. Pistillate ray florets show significant differences from perfect disc florets as reflected by the zygomorphic shape of the floral apex and a shift of floral merosity from pentamery to tetramery. Loss of stamens in ray florets occurs due to abortion of primordia after initiation.