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KRAS is one of the most widely prevalent proto-oncogenes in human cancers. The constitutively active KRAS oncoprotein contributes to both tumor onset and cancer development by promoting cell proliferation and anchorage-independent growth in a MAPK pathway-dependent manner. The expression of microRNAs (miRNAs) and the KRAS oncogene are known to be dysregulated in various cancers, while long noncoding RNAs (lncRNAs) can act as regulators of the miRNAs targeting KRASoncogene in different cancers and have gradually become a focus of research in recent years. In this review article, we summarize recent advances in the research on lncRNAs that have sponging effects on KRAS-targeting miRNAs as crucial mediators of KRAS expression in different cell types and organs. A deeper understanding of lncRNA function in KRAS-driven cancers is of major fundamental importance and will provide a valuable clinical tool for the diagnosis, prognosis, and eventual treatment of cancers.

In this study, the antimicrobial effect of exopolysaccharide (EPS) extracted from Enterococcusstrains [E. duransK48 (MT437,248), E. faeciumR114 (MT437,249) and E. faeciumT52 (MT437,250)] isolated from Kishk was applied against some foodborne pathogenic bacteria using well diffusion and microdilution methods. The antioxidant activity of EPS was also evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay and ferric reducing antioxidant power (FRAP) method. The cytotoxicity effect of EPS on human Gingival Fibroblast (HGF) cell line was also assessed. The results obtained by antimicrobial test showed that the most resistant bacteria to the examined EPS was Listeria monocytogenes, and the most susceptible were Staphylococcus aureusand E. faecalis. The results showed that the DPPH inhibitory percentage of EPS (25 mg/mL) from E. duransK48, E. faeciumR114, and E. faeciumT52 was 53%, 58% and 64%, respectively. EPS from E. faeciumT52 displayed the highest reducing power, but statistically, there was no significant difference between the reducing power of EPS T52 and EPS R114 (P ≥ 0.05). The lowest toxicity percentage of EPS k48, EPS T52, and EPS R114 on normal human cell line at a concentration of 0.2 mg/mL was 10%, 15%, and 13%, respectively, which was statistically significant (P < 0.05). The obtained results in the present study indicate that EPS from the examined LAB strains with no in vitro cytotoxicity can be a potential source of natural antioxidant and antibacterial agent to be used in food and pharmaceutical industries.

One of the most effective methods for increasing the antimicrobial activity of a substance is to combine it with one or more other antimicrobial agents. The aim of the present study was to evaluate the antimicrobial effect of buforin I and nisin alone and investigate the synergistic action of these compounds against the most important food spoilage microorganisms, including Bacillus subtilis, Staphylococcus epidermidis, Listeria innocua, Escherichia coli, Salmonellaserovar Enteritidis, Aspergillus oryzae, Rhodotorula glutinis,and Geotrichum candidum. The results of MIC and MBC or minimum fungicidal concentration examinations showed that buforin I had higher antimicrobial activity than nisin on all microbial strains used in this study (P≤ 0.5). E. coliwas the most resistant to both antimicrobial agents, whereas L. innocuaand S. epidermidiswere the most sensitive to nisin and buforin I, respectively. The results of synergistic interaction between buforin I and nisin indicated that the combination of buforin I and nisin on B. subtilis, S. epidermidis,and A. oryzaeshowed a synergistic effect, whereas it had no effect on Salmonellaserovar Enteritidis and G. candidum. The combination of buforin I and nisin showed a partial synergistic effect on L. innocua, E. coli,and R. glutinis. Assessment of viability of the microorganisms under the antimicrobial agents alone and in combination with each other at MICs and fraction inhibitory concentrations indicated that use of these antimicrobial agents in combination enhances antimicrobial activity at lower concentrations of both agents. The present study investigated the antimicrobial properties of buforin I against food spoilage microorganisms for the first time and suggests that its use alone or with nisin may provide a clear horizon for the application of antimicrobial peptides as natural preservatives. Thus, the combination of antimicrobial peptides and traditional antimicrobial food preservatives could be a promising option for the prevention of contamination, spoilage, and infestation of food and beverage products.

Background: Thanatin is the smallest member of Beta-hairpin class of cationic peptide derived from insects with vast activities against various pathogens. Objective: In this study, the antimicrobial activity of this peptide against some species of human bacterial pathogens as well as its toxicity on NIH cells were evaluated. Methods: Thanatin DNA sequence was cloned into pcDNA3.1+ vector and transformed into a DH5α bacterial strain. Then the recombinant plasmids were transfected into HEK-293 cells by calcium phosphate co-precipitation. After applying antibiotic treatment, the supernatant medium containing thanatin was collected. The peptide quantity was estimated by SDS-PAGE and GelQuant software. The antimicrobial activity of this peptide was performed with Minimum Inhibitory Concentration (MIC) method. In addition, its toxicity on NIH cells were evaluated by MTT assay. Results: The peptide quantity was estimated approximately 164.21 μmolL-1. The antibacterial activity of thanatin was estimated between 0.99 and 31.58 μmolL-1 using MIC method. The result of cytotoxicity test on NIH cell line showed that the peptide toxicity up to the concentration of 394.10 μmolL-1 and for 48 hours, was not statistically significant from negative control cells (P>0.05). The antimicrobial assay demonstrated that thanatin had an antibacterial effect on some tested microorganisms. The results obtained in this study also showed that thanatin had no toxicity on mammalian cell lines including HEK293 and NIH. Conclusion: Antimicrobial peptides such as thanatin are considered to be appropriate alternatives to conventional antibiotics in treating various human pathological diseases bacteria.

Background: Prokaryotic systems such as E. coli are among the most affordable and simplest hosts which are being employed to express recombinant proteins, nevertheless without appropriate signal peptide these systems cannot be used for secretory proteins. Bovine pancreatic ribonuclease A is a protein with four disulfide bonds which might be used as an immunoenzyme for immunotherapy. Consequently, the production of this recombinant protein, using prokaryotic system, requires a suitable signal peptide to protect disulfide bonds and to prevent misfolding. Objective: This study was designed to predict the best signal peptides to express bovine pancreatic ribonuclease A protein in E. coli. Method: In this study, 42 signal sequences were selected from data bases and the most important features of them were evaluated. First, n, h and c regions of signal peptides and their probability were investigated by signalP software’s version 4.1. Then, physico-chemical features of them were evaluated by Portparam and SOLpro. Also, secretion sorting and sub-cellular localization sites were evaluated by PRED-TAT and ProtcompB software programs. Results: The results showed that among all studied signal peptides only 28 out of 41 remained signal peptides could be considered as appropriate secretory signal peptides. Conclusion: Finally, Phage shock protein E, ranked as the best signal peptide and after that, pectate lyase B, F41 fimbrial protein and Lipopolysaccharide export system protein lptA considered as the next best signal peptides which were approved by in silico tools as the most appropriate secretory signal peptides in E. coli. However, further experiments are required to validate these in silico results.

The production of polysaccharides derived from lactic acid bacteria (LAB) can be a valuable alternative to current polysaccharides. In this study, eight samples of Kishk (traditional dairy product) were collected in sterile conditions and directly cultured on MRS agar medium. Following purification and examination of microscopic, macroscopic characteristics and doing biochemical tests, 143 isolates were selected, and the production of exopolysaccharide (EPS) was investigated by the ruthenium red and disc methods. The EPS production of 79 isolates was confirmed. Total carbohydrate of EPS was determined by the phenol sulfuric acid method. Finally, Enterococcus duransK48, Enterococcus faeciumR114, and Enterococcus faeciumT52 strains were selected as the best EPS producers. The optimization of EPS production was then performed using Central Composite Design (CCD) and Response Surface Methodology (RSM) approaches. Optimization plots showed the highest EPS yield for E. duransK48, E. faeciumR114, and E. faeciumT52 occurred at 38.4, 37.4 and 36.7 °C and pH of 5.9, 5.6 and 5.8, respectively, cultured in a Sucrose-MRS medium. Under optimal conditions, the maximum predicted and actual production of EPSs for the examined isolates were 3.18, 3.21, 2.99 and 3.02, 3.15, 3.15, g L−1, respectively. As determined by Gel Permeation Chromatography, the EPSs molecular weights were in the range of 2.93 × 105to 3.52 × 105 Da. Analysis of the component monosaccharides by HPLC showed that all three tested EPSs were heteropolysaccharides. After appropriate evaluation, the EPSs produced by native species of LAB isolated from Iranian Kishk could be of interest for industrial applications or as functional food ingredients.

Clostridium perfringens-induced necrotic enteritis (NE) is an economically important disease of broiler chickens. The present study evaluated the effect of C. perfringenson the intestinal histomorphometry, enteric microbial colonization, and host immune responses using 3 experimental NE reproduction methods. The experimental groups consisted of 1) unchallenged Control diet (corn-soybean meal), 2) Control diet + Eimerainoculation at d 11 followed by C. perfringenschallenge at d 15 (ECp), 3) Wheat-based diet + C. perfringenschallenge (WCp), and 4) Wheat-based diet + Eimeriainoculation followed by C. perfringenschallenge (WECp). The results showed that chickens receiving ECp and WECp had reduced (P< 0.05) bird performance coupled with enteric gross lesions and epithelial damage at d 17 and 24 of age compared to unchallenged control birds. These ECp and WECp administered birds also had increased (P< 0.05) ileal colonization by clostridia and E. coliat d 17 and 24, while the resident Lactobacilluscounts were reduced (P< 0.05) at d 24 of age. Furthermore, at d 24, jejunal transcription of IL-6, IL-10, annexin-A1 and IL-2 genes was upregulated (P< 0.05) in the ECp group, whereas the transcription of TNF receptor associated factor (TRAF)-3 gene was increased (P< 0.05) in WECp treated birds when compared to unchallenged control group. Additionally, stimulation of chicken splenocytes and cecal tonsilocytes with virulent C. perfringensbacilli or their secretory proteins resulted in a higher (P< 0.05) frequency of T cells and their upregulation of MHC-II molecule, as determined by flow cytometry. These findings suggest that C. perfringens, while inducing epithelial damage and changes in microbiota, can also trigger host immune responses. Furthermore, NE reproduction methods using coccidia with or without the wheat-based dietary predisposition seem to facilitate an optimal NE reproduction in broiler chickens and thus, may provide better avenues for future C. perfringensresearch.

Heterosis, defined as the superior performance of F1hybrids over their parents, has been used for centuries to increase yield in plants and animals. However, the biological basis of heterosis is poorly understood, as it does not follow standard genetic models. Based on theoretical prediction that genomic imprinting may mimic overdominance and heterosis, we investigated whether imprinting effects could explain heterosis. We used purebred and reciprocal cross Bos taurus taurus(Angus, A) and Bos taurus indicus(Brahman, B) cattle that display one of the strongest known heterotic phenotypes in mammals. We intercepted concepti at mid-gestation, when the fetus enters accelerated growth but does not yet display heterosis in weight, to map drivers of heterosis in placenta as the major organ regulating prenatal growth that predicts postnatal performance. Our analyses at the gross morphological, histomorphological and molecular level revealed nine maternal, three paternal and nine polar over/underdominance patterns consistent with genomic imprinting effects but only two with additive genetic effects. Strikingly, placental polar overdominance patterns at midgestation mirrored polar overdominance in birth weight. We found that increased nutrient supply via maternal A genome effects on placental phenotype, combined with increased nutrient transfer capacity via polar overdominance effects of paternal B genome on umbilical cord phenotype, provide the basis for heterosis in birth weight of B×A hybrids. Polar overdominance in expression of imprinted IGF2Rin Placenta fetalisof B×A hybrids, and correlation of transcript abundance with number of feto-maternal syncytia in placenta, are consistent with an active signaling role of IGF2R in placenta and a further indicator of superior placental performance as the driver of heterosis. In conclusion, we have shown that phenotypic expression patterns consistent with imprinting effects on placental and umbilical cord parameters and in agreement with the conflict of interest theory of genomic imprinting drive mammalian heterosis in utero.