Comprehensive review of CRISPR-based gene editing: mechanisms, challenges, and applications in cancer therapy.

The CRISPR system is a revolutionary genome editing tool that has the potential to revolutionize the field of cancer research and therapy. The ability to precisely target and edit specific genetic mutations that drive the growth and spread of tumors has opened up new possibilities for the development of more effective and personalized cancer treatments. In this review, we will discuss the different CRISPR-based strategies that have been proposed for cancer therapy, including inactivating genes that drive tumor growth, enhancing the immune response to cancer cells, repairing genetic mutations that cause cancer, and delivering cancer-killing molecules directly to tumor cells. We will also summarize the current state of preclinical studies and clinical trials of CRISPR-based cancer therapy, highlighting the most promising results and the challenges that still need to be overcome. Safety and delivery are also important challenges for CRISPR-based cancer therapy to become a viable clinical option. We will discuss the challenges and limitations that need to be overcome, such as off-target effects, safety, and delivery to the tumor site. Finally, we will provide an overview of the current challenges and opportunities in the field of CRISPR-based cancer therapy and discuss future directions for research and development. The CRISPR system has the potential to change the landscape of cancer research, and this review aims to provide an overview of the current state of the field and the challenges that need to be overcome to realize this potential.

Application of multiplex PCR for Rapid and sensitive detection of human papillomaviruses in cervical cancer.

OBJECTIVES: Reffering to an increase in cervical cancer in the recent years, rapid, sensitive and economical detection of human papillomaviruses (HPVs) as causative agents of cervical cancer is important. The traditional methods for the detection of HPVs in cervical cancer, such as pap smear, suffer from limitation and PCR has a potential to overcome the limitaitons. The purpose of present research work was to identify the five important strains of HPV (16, 18, 31, 33 and 45) simultaneously by Multiplex PCR application. METHODS: Study was done on 100 cervical lesions of women. DNA was extracted from specimens by a genomic DNA purification kit. A 5-plex PCR was developed for the simultaneous detection of major HPV. Five pair of new primers was designed for detection of HPV 16, 18, 31, 33 and 45 by Multiplex PCR. RESULTS: Among the 100 evaluated samples, 82 were found positive to HPVs. In the meantime the highest rate of infection was for HPV 16. Also 30 of HPV positive samples had infections with two or more HPV types. CONCLUSION: Multiplex PCR assay used in present study can provide a rapid, sensitive and economical method for detection of viral infections and is applicable to small volumes of vaginal samples.

Bovine herpesvirus type 5 in semen samples from bulls in Iran.

Bovine herpesvirus 5 (BoHV-5) is an important pathogen of the central nervous system and has already been described in the genital tract of cattle and in semen. This virus is responsible for sporadic epizootics of fatal meningoencephalitis of calves. The objective of the present study was the identification and characterization of BoHV-5 in semen samples from bulls for the first time in Iran. DNA was extracted from bull semen samples, and the glycoprotein D (gD) gene of BoHV-5 and also the thymidine kinase (tK) gene of bovine herpesvirus 1 (BoHV-1) were amplified by PCR assay. The results showed a high prevalence of BoHV-5 (73.2 %) and BoHV-1 (25.89 %) in Iranian bull semen samples. In addition, in order to identify and compare BoHV-5 isolated from Iranian bulls with other isolates from all over the world, the gD gene of this virus was cloned and sequenced. A BLAST search showed that the sequence of the gD gene of BoHV-5 from Iran was 99 % identical to other sequences in the GenBank database. The present study indicated that semen samples are important transmission sources of BoHV-5 virus in Iranian bulls.

Study of the frequency of Clostridium difficile tcdA, tcdB, cdtA and cdtB genes in feces of Calves in south west of Iran.

BACKGROUND: Clostridium difficile (C. difficile) is a gram-positive, toxin-producing bacillus which is an intestinal pathogen in both humans and animals and causes a range of digestive disorders including inflammation of the bowel, abdominal pain, fever and diarrhea. C. difficile toxins include enterotoxin (Toxin A), cytotoxin (Toxin B) and a binary toxin. Two large protein toxins A and B are encoded by separate genes, tcdA and tcdB. Clostridium difficile infection (CDI) mainly caused by the activity of the genes tcdA and tcdB. The binary toxin is encoded by the genes cdtA and cdtB. The binary toxin caused increased adherence of bacteria to intestinal epithelium. The aim of the present study was isolation of C. difficile from feces of calves, and study of the frequency of C. difficile virulence genes. METHODS: 150 samples of fresh feces from calves were collected and C. difficile was isolated from feces of calves using bacterial culture methods. DNA was extracted by a genomic DNA purification kit. Then PCR method was used for definitive diagnosis of C. difficile. Multiplex PCR method performed for identification of tcdA, tcdB, cdtA and cdtB genes. In the final stage antimicrobial resistance determining was carried out by standard Bauer-Kirby disk diffusion method. RESULTS: C. difficile was isolated from 90 samples (60%). The tcdA was observed in 8 isolates (8.8%), tcdB in 16 isolates (17.7%), cdtA in 8 isolates (8.8%) and cdtB in 14 isolates (15.5%). Only 1 isolated (1.1%) was containing all four genes tcdA, tcdB, cdtA and cdtB, 2 isolates (2.2%) only had both tcdA and tcdB genes, and there was no sample positive only for both cdtA and cdtB. The highest rate of drug resistance was against clindamycin (100%) and the highest rate of drug sensitivity was against ciprofloxacin (50%). CONCLUSION: The results showed high incidence of C. difficile and also high antibiotic resistance of this bacterium, but frequency of strains containing virulence genes (tcdA, tcdB, cdtA and cdtB) was low.