فصلنامه تازه های بیوتکنولوژی سلولی مولکولی
پیاپی 41 (زمستان 1399)

The covid-19 virus is a severe and contagious viral infection that appeared in Wuhan, China in late December 2019 and spread rapidly around the world. Despite numerous studies on the new virus, its origins remain unclear. Determining the exact source of this virus can be helpful in finding solutions to control this virus and similar viruses in the future.

Aim and

Coronavirus is the causative agent of COVID-19 infectious pneumonia, which was introduced by the World Health Organization in 2020 as a global epidemic. Due to the fact that its inhibitory mechanisms have not been well understood so far, in this article we decided to investigate the inhibitory mechanisms of Spike, Main Protease and Papain-like protease proteins in the coronavirus.

In the present study, all calculations were performed by AutoDock 4.2 (2013), AutoDockTools 4.2 (2013) and Cluspro2.0 (2017). Lamarckchr('39')s genetic algorithm was used to search for protein levels, and 200 were performed in each of the docking models. Finally, the interaction of protein binding and inhibitor compounds and hydrogen and hydrophobic binding was calculated by Poseview and DIMPLOT software.
 

The interaction study showed that the amino acids His163, His164, Gln189, Glu166, Cys145 and Phe140 play a key role in the inhibitory interaction of GC-376 with Mpro protein due to hydrogen bonds. Also, the study of the binding energy of the inhibitor compound to the protein shows that this compound is attached to the inhibitor with a binding energy of -6.36 kcal / mol. The docking results of PLpro complex showed that the amino acids Tyr268, Gln269, and Asp164 play a key role in the interaction of GRL0617 inhibitor with PLpro protein due to hydrogen bonds and the binding energy of the inhibitor compound to PLpro protein was -9.69. Finally, the study of the interactions of Spike protein and LCB1 peptide using Cluspro and DIMPLOT software showed that there are several hydrophobic and polar interactions between different amino acids of these two compounds, the most important of which can be He noted the interaction of the amino acid Tyr489 in the Spike protein with the amino acids Leu6 and Gln7 in the inhibitory peptide.
 

The results of this study showed that the inhibitory compounds presented in this article can well inhibit vital proteins important in coronavirus due to polar and hydrophobic interactions.

Aim and

In the past two decades, proteins and peptides have become an important class of therapeutic drugs. However, their sensitivity to chemical and physical degradation has posed challenges for scientists. Approximate 90% of the chicken feather of slaughterhouse waste is Keratin. Keratin protein is insoluble in water and has a strong tendency to accumulate and precipitate. Today, the stability of proteins in pharmaceutical applications is of great importance.

In this study, Keratin was extracted from feather by sodium hydroxide 0.2 M and hydrolyzed by 8% (V/V) Alcalase enzyme in 55 Celsius, at 8 pH. The hydrolyzed Keratin solution was chemically modified by alkylation and sulfitolysis to reduce aggregation. Keratin solubility, degree of chemical modification, percentage of stability, mol amount of free thiol, also DLS, and FTIR of the samples were investigated.

The result showed that the degree of chemical modification of Keratin in the alkylation method was 72% and the sulfitolysis method was 66%. The chemical modification of hydrolyzed Keratin was reduced aggregation at pH3 to 288.65% and 335.3% for alkylation method and sulfitolysis respectively. Investigation of the stability and preservation of protein content showed that the stability of modified Keratin by alkylation method was 81.9% and by sulfitolysis method was 86.3% in 30 days, but the hydrolyzed Keratin as a control preserved only 9.8% of protein content. The result of the DLS test shows that the Keratin modified by alkylation in water has PI=0.476 and a mean particle size of 157.3 nm and Keratin modified by sulfitolysis in water has PI=0.475 and a mean particle size of 136.2 nm, which was more uniform and dispersed than the hydrolyzed Keratin with PI=0.552 and a mean particle size of 990.3 nm.

The chemical modification of hydrolyzed Keratin was a permanent change and binding of expected groups increased the Keratin solubility in aqueous solution and decreases the aggregation at acidic pH. The results of the FTIR analysis confirmed the chemical modification of Keratin.

Aim and

Many microorganisms produce antimicrobial agents protecting them in extreme environmental conditions. Exiguobacterium sp. has particularly been adapted to their environment and is of wide diversity depending on the species and environmental conditions. The present study aims to study on the isolation, identification, and examination of antimicrobial property of bioactive compounds produced by Exiguobacterium acetylicum PTCC 1765.

E. acetylicum was taken from Iranian Research Organization for Science and Technology and was cultured in Corynebacterium broth and nutrient broth. Agar diffusion and well diffusion techniques were used to study the antimicrobial effect of supernatant of this bacterium against pathogenic and standard strains of bacteria such as Escherichia coli, Salmonella enterica, Staphylococcus aureus, Shigella dysenteriae and compounds with antibacterial property were identified using GC/MS.

E. acetylicum culture’s supernatant displayed a good antimicrobial property. Its greatest effect was observed during Well diffusion technique over salmonella entrica servpvar paratiphi PTCC 1231 with 8.5 mm zone of inhibition based on GC/MS analysis 2- ethyl  hexyl parametoxy cynamate, 1-2-benzen-dicarboxilic acid, 1-7- dimethyl 3- phenil- thilidin byciclo (1-2-2) – heptanes-2- on and phenol 2-4 bis(1-1-dimethyle ethyle)were dominant compounds.

Nowadays, by increased resistance of antibiotics and the complexities resulted from consumption of chemical pharmaceutics, using alternative medicines, seems necessary. The supernatant of E. acetylicum culture having high antimicrobial capability and useful compounds with restricting property can be suggested as an antimicrobial agent. While comprehension studies are needed to affirm the effect of this bacteria and its resulting metabolites in the human body conditions.

Aim and

Asthma is one of the most common chronic diseases of childhood that causes frequent hospital visits and absenteeism from school. In this study, the therapeutic effect of adding probiotics to standard treatment in children with mild to moderate asthma was determined.

This double-blind clinical trial study was performed on 120 patients aged 3 to8 years with mild to moderate asthma referred to the specialized pediatric clinic of Heshmatieh Hospital in Sabzevar. Patients were divided into two groups of intervention and control by simple random sampling based on permutation block and were given probiotic and placebo drops for two months and was taught how to use them correctly. At the end of the second month, the standard asthma control test (ACT) questionnaire was completed by their searcher. The collected data were analyzed using SPSS19 software.

In the study of the consequences following the addition of probiotics to standard treatment for two months in these patients, no statistically significant change in asthma control (relative control and lack of control) was observed between the two groups (P <0.05).

According to the results of this study and the lack of statistically significant effect between the two groups of intervention and control, the addition of probiotics to standard asthma treatment in children with mild to moderate asthma is not recommended.

Staphylococcus aureus is a common cause of nosocomial infections and increased resistance to antimicrobial agents in this bacterium is one of the major problems in health care. We also see resistant strains of this bacterium that are important pathogens in the development of the disease. The control of these bacteria is very important from a health and economic point of view, so the aim of this study was to investigate the prevalence of methicillin mecA resistance gene and determine the pattern of antibiotic resistance in existing samples of Staphylococcus aureus and to evaluate the antibacterial activity of silver nanoparticles against Gram-positive Staphylococcus aureus.

In this cross-sectional study, 59 staphylococcus aureus specimens were collected from 11 nature detection laboratories. These samples were identified using standard laboratory methods and specific culture. PCR was used to evaluate the frequency of mecA gene. In order to use the antibiotic susceptibility pattern of the strains, the disk diffusion method is performed based on the CLSI protocol. Silver nanoparticles were made from ginger extract and Real Time PCR was used to evaluate the effect of silver nanoparticles on mecA gene expression.

Out of 59 samples of Staphylococcus aureus, 51 samples were resistant to methicillin. Phenotypic evaluation of antibiotic resistance pattern of methicillin-resistant Staphylococcus aureus strains showed that the results showed that 90% of isolates to penicillin, 85% to erythromycin, 84% to ceftriaxone, 53% to amikacin, 49% to gentamicin, 47% to piracyl 45% were resistant to spirofloxacin 37% to imipetmo 35% to linezolid, ie the highest antibiotic resistance was to penicillin 90%, erythromycin 85% and the lowest to imipetmo 37% and linzolid 35, respectively. Molecular analysis showed the presence of mecA gene in all samples. The results of real-time study showed that the effect of nanoparticles on mecA gene expression is significant.
Discussion and

The presence of 51 resistant samples out of 59 samples in the present study indicates an increase in resistance of methicillin-resistant Staphylococcus aureus to other antibiotics, which is a serious warning for the treatment of Staphylococcus aureus infections. And the effectiveness of silver nanoparticles on mecA gene expression shows that we can use this substance instead of existing antibiotics.

Cancer stem cells known as initiating tumor cells have self-renewal and differentiation in tumor mass and they are resistant to therapy. Therefore traditional treatment like radiotherapy and chemotherapy cannot control tumor cells proliferation. Searching new therapies to control cancer stem cells is necessary for inhibition of tumor cells. In the specific microenvironment,  cancer stem cells undergo unequal division and form new tumor cells with different characteristics in terms of genetics and metabolism. Therefore, therapeutic based on the controlling of proliferation and differentiation of cancer stem cells can be a good strategy for eliminating of various tumors.
In this paper we will review metabolism and mitochondrial context in cancer stem cells and we would discuss the possibly of targeting metabolism in cancer stem cells.

COVID-19, the disease caused by SARS-CoV-2, is a highly contagious disease. The World Health Organization has declared the ongoing outbreak to be a global public health emergency. Currently, the research on SARS-CoV-2 is in its primary stages. Based on current published evidence, this review systematically summarizes the epidemiology, clinical characteristics, diagnosis, treatment and prevention of COVID-19. It is hoped that this review will help the public to recognize and deal with SARS-CoV-2, and provide a reference for future studies.