Evaluation and Comparison of Clostridium Epsilon-Alpha Fusion Gene Expression Using Different Commercial Expression Vector

Clostridium perfringens and Clostridium septicum are gram-positive, anaerobic, spore-forming rods and pathogens for humans and livestock, which are widespread in nature as well as human and animal digestive systems. C. perfringens produces numerous different exoproteins, which are various systems of action. The major C. perfringens toxins include alpha, beta, epsilon, and iota. C. perfringens are classified into five groups (A-E) on the basis of the production of these lethal toxins. Furthermore, toxins secreted from C. septicum include alpha, beta, delta, and gamma. Epsilon and alpha toxins of C. perfringens and C. septicum are the major causes of enterotoxemia and braxy in sheep and goats, respectively. The production of recombinant immunogenic proteins of these bacteria using suitable expression vectors and expression prokaryotic hosts can be a convenient method for the reduction of the costs and production time of clostridial anaerobic vaccines. In the present study, recombinant Escherichia coli strain TOP10 containing pJETεα was used for the evaluation of C. perfringens type D and C. septicum epsilon-alpha fusion protein using different commercial vectors. After the extraction of pJETεα from the recombinant cell, it was digested by NdeI and XhoI restriction enzymes and subcloned into pET22b (+), pET26b (+), and pGEM-B1 expression vectors in E. coli/Rosetta and E. coli/BL21 (DE3). The expression of recombinant fusion toxin was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotting in three different temperatures, various isopropyl β-D-1-thiogalactopyranoside (IPTG) gradients, and different times using pGEMεα, pET22εα, and pET26εα vectors in E. coli/Rosetta and E. coli/BL21 (DE3). According to the obtained results, recombinant E. coli/Rosetta/pET22εα showed better expression at a temperature of 37°C after 6 h of induction by IPTG.

Dual relationship between long non-coding RNAs and STAT3 signaling in different cancers: New insight to proliferation and metastasis

Uncontrolled growth and metastasis of cancer cells is an increasing challenge for overcoming cancer, and improving survival of patients. Complicated signaling networks account for proliferation and invasion of cancer cells that need to be elucidated for providing effective cancer therapy, and minimizing their malignancy. Long non-coding RNAs (lncRNAs) are RNA molecules with a length of more than 200 nucleotides. They participate in cellular events, and their dysregulation in a common phenomenon in different cancers. Noteworthy, lncRNAs can regulate different molecular pathways, and signal transducer and activator of transcription 3 (STAT3) is one of them. STAT3 is a tumor-promoting factors in cancers due to its role in cancer proliferation (cell cycle progression and apoptosis inhibition) and metastasis (EMT induction). LncRNAs can function as upstream mediators of STAT3 pathway, reducing/enhancing its expression. This dual relationship is of importance in affecting proliferation and metastasis of cancer cells. The response of cancer cells to therapy such as chemotherapy and radiotherapy is regulated by lncRNA/STAT3 axis. Tumor-promoting lncRNAs including NEAT1, SNHG3 and H19 induces STAT3 expression, while tumor-suppressing lncRNAs such as MEG3, PTCSC3 and NKILA down-regulate STAT3 expression. Noteworthy, upstream mediators of STAT3 such as microRNAs can be regulated by lncRNAs. These complicated signaling networks are mechanistically described in the current review.

Pre-clinical investigation of STAT3 pathway in bladder cancer: Paving the way for clinical translation

Effective cancer therapy requires identification of signaling networks and investigating their potential role in proliferation and invasion of cancer cells. Among molecular pathways, signal transducer and activator of transcription 3 (STAT3) has been of importance due to its involvement in promoting proliferation, and invasion of cancer cells, and mediating chemoresistance. In the present review, our aim is to reveal role of STAT3 pathway in bladder cancer (BC), as one of the leading causes of death worldwide. In respect to its tumor-promoting role, STAT3 is able to enhance the growth of BC cells via inhibiting apoptosis and cell cycle arrest. STAT3 also contributes to metastasis of BC cells via upregulating of MMP-2 and MMP-9 as well as genes in the EMT pathway. BC cells obtain chemoresistance via STAT3 overexpression and its inhibition paves the way for increasing efficacy of chemotherapy. Different molecular pathways such as KMT1A, EZH2, DAB2IP and non-coding RNAs including microRNAs and long non-coding RNAs can function as upstream mediators of STAT3 that are discussed in this review article.

Metagenomic investigation of bacteria associated with dental lesions: a cross-sectional study

BACKGROUND

Dental caries is considered as one of the most significant global health problem over the world. Dental caries initiates from bacterial shifts within the supragingival biofilm, then a polymicrobial biofilm is formed on the surface of tooth, and finally various bacterial species aggregate in a complex-organized manner. The exploiting variability in 16S rRNA gene sequence has been considered as a cost-efficient high-throughput characterization approach in human oral microbiome investigations. The aim of this study is to characterize bacterial species associated with superficial dental biofilm, underlying carious dentine and root caries lesion by16S rRNA gene-based metagenomic analysis.

MATERIAL AND METHODS

Herein, the bacterial communities in carious dentin lesion, biofilm and root canal samples of 30 subjects (aged 4-76 years) admitted to a clinic in Tehran during 2017 were investigated using a culture independent approach. Total genomic DNA of each tissue was subjected to metagenomic identification of bacteria using a nested PCR assay and 16S rRNA library construction method.

RESULTS

31 samples collected from 30 consenting patients (29 samples from 29 patients ant two biofilm samples from one patient). Bioinformatics analyses of a-800bp sequences of the second step of Nested-PCR revealed presence of 156 bacterial isolates in carious (n=45), biofilm (n=81) and root canal (n=30) specimens. Prevotella spp., Lactobacillus vaginalis, and streptococcus spp. showed higher prevalence in carious dentin, root and biofilm samples, respectively.

CONCLUSIONS

Exploring the dental microbiota and comparing them in health or diseased conditions is critical step in the determination of human general health. The method applied in this study could identify bacteria related to the three dental lesions. However, due to lack of data for comparison in Genbank or because of the sequence similarity lower than 98% for most identified bacteria, the use of more powerful approaches like NGS platforms or typing of multiple loci (MLST) in future studies is recommended.

Robust stability of teleoperation systems with time delay: a new approach

In this paper, we propose an approach to the control of linear teleoperation systems under time delays. Unlike traditional delay-robust control systems that guarantee passive communication channel through the transmission of wave variables, the new approach uses the concept of absolute stability for the physically expressive Lawrence's four-channel structure for transmitting the standard power variables, i.e., force and position. By incorporating kinesthetic performance requirements, we derive an absolutely stable four-channel controller that is transparent when time delay is negligible. Experimentally, the study evaluates and compares the performance of the proposed controller with that of a benchmark wave variable-based controller. The results indicate contact stability for large delays, a lack of position drift, and improved position and force tracking in both the free motion and rigid contact regimes for small delays.

Bounded-Impedance Absolute Stability of Bilateral Teleoperation Control Systems

Available passivity-based robust stability methods for bilateral teleoperation control systems are generally conservative, as they consider an unbounded range of dynamics for the class of passive operators and environments in the complex plane. In this paper, we introduce a powerful 3D geometrical robust stability analysis method based on the notions of wave variables and scattering parameters. The methodology, which was originally a 2D graphical method used in microwave systems for single-frequency analysis [1], is further developed in this paper for teleoperation and haptic systems. The proposed method provides both mathematical and visual aids to determine bounds or regions on the complex frequency response of the passive environment impedance parameters for which a potentially unstable system connected to any passive operator is stable, and vice-versa. Furthermore, the method allows for the design of bilateral controllers when such bounds are known, or can even be utilized when the environment dynamics are active. The geometrical test can also be replaced by an equivalent mathematical condition, which can easily be checked via a new stability parameter. The proposed method results in less conservative guaranteed stability conditions compared to the Llewellyn's criterion; thus, promising a better compromise between stability and performance. The new method is numerically evaluated for two bilateral control architectures.