Biochemical and Biological Evaluation of an L-Asparaginase from Isolated Escherichia coli MF-107 as an Anti-Tumor Enzyme on MCF7 Cell Line

Background: One of the most widely used anticancer agents is microbial L-ASNase. Herein, we assessed the biochemical and biological properties of an isolated L-ASNase from a Gram-negative bacteria strain, Escherichia coli MF-107. Methods: Using garden asparagus, we obtained several bacterial isolates. These strains were further screened for L-ASNase activity. A promising bacterial isolate was selected for L-ASNase production and subsequent purification. The molecular weight of purified L-ASNase was determined. The MTT assay was applied to assess the cytotoxic effect of the purified enzyme. Also, for caspase activity determination and the apoptotic effect of purified enzyme on in cells, we conducted a real-time PCR method. Results: The molecular weight of the enzyme was approximately 37 kDa. In the pH range of 7.5 to 8, the enzyme had considerable stability. At 35 °C, the purified L-ASNase optimum activity was recorded. The cytotoxic effect of the enzyme on treated cells was dose-dependent with an IC50 value of 5.7 IU/ml. The Bax gene expression considerably raised by 5.75-fold (p < 0.001) upon L-ASNase treatment. On the other hand, the anti-apoptotic Bcl-2 gene expression showed a 2.63-fold increase compared to the control (p < 0.05). It was detected that the mRNA levels of caspase-3 and p53 were considerably upregulated (5.93 and 1.85-fold, respectively). We did not find any alternation in the caspase-8 activity of the treated cells compared to untreated cells. Conclusion: In this research, the proliferation of the breast cancer cells remarkably inhibited via the cytotoxic effect of isolated L-ASNase from microbial sources.

Microsatellite Marker Analysis for Laboratory Mice Profiling.

BACKGROUND: The key point in the production procedure of inbred animals is checking the genetic purity. Skin grafting and coat color test are used traditionally to prove genetic purity, but they have some disadvantages. Recent advances in DNA profiling have enabled scientists to check easily the genetic purity of laboratory animals. In the current study, a set of microsatellite markers was designed to check the purity of inbred laboratory mice. MATERIALS AND METHODS: Twenty microsatellites located on 20 chromosomes were employed to create a distinctive genetic profile for parentage analysis. Each individual primer was designed based on distinguishable colors and separable sizes. RESULTS: Twenty specific microsatellite markers were used in the polymerase chain reaction mixture to identify inbred BALB/cJ strains. Our results confirmed that the designed microsatellites are excellent genetic markers for testing inbred BALB/cJ strain in laboratories. CONCLUSION: Our study showed that genetic profiling using microsatellite markers allows us to detect the genetic differences of laboratory mouse species in quality control tests and validation steps.

Rational design of hyper-glycosylated interferon beta analogs: a computational strategy for glycoengineering.

Glycoengineering has been successfully used to improve the physicochemical and pharmaceutical properties of therapeutics. One aspect of glycoengineering is to introduce new N-linked glycosylation consensus sequences (Asn, X, Thr/Ser) into desirable positions in the peptide backbone by mutational insertion to generate proteins with increased sialic acid content. In the current work, human interferon beta (huIFN-ß) was used as a model to identify the potential positions for the addition of new N-glycosylation sites. A computational strategy was employed to predict the structural distortions and functional alterations that might be caused by the change in amino acid sequence. Accordingly, three-dimensional (3D) structures of the designed huIFN-ß analogs were generated by comparative modeling. Molecular dynamics (MD) simulation was carried out to assess the molecular stability and flexibility profile of the structures. Subsequently, for the purpose of glycoengineering huIFN-ß, analogs with 3D structures more similar to the wild-type huIFN-ß and exposed Asn residue in the new N-glycosylation site were identified. These modeling procedures indicated that the addition of the new N-glycosylation site in the loop regions had lower constraining effects on the tertiary structure of the protein. This computational strategy can be applied to avoid alterations in the 3D structure of proteins caused by changes in the amino acid sequences, when designing novel hyper-glycosylated therapeutics. This in turn reduces labor-intensive experimental analyses of each analog.