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The Effect Of Lactobacillus Paracasei Isolated From Yoghurt On The Growth And Production Of Staphylococcus Aureus Enterotoxin
Mahnoosh Parsaeimehr, Ali Misaghi, Afshin Akhondzade, Ashkan Jebelli Javan , Mehdi Taheri, Nabi Shariatifar,
Volume 8, Issue 3 (9-2014)
Abstract
 Background and Aim: Probiotics are useful bacteria which, after being consumed, leave useful effects on human health. The present study was conducted to examine the antimicrobial effect of Lactobacillus paracasei on pathogenic bacteria, especially on Staphylococcus aureus in the field of food microbiology.

 Materials and Methods: In this study, the effect of Lactobacillus paracasei isolated from yoghurt (1×108 cfu/ml) on the growth of Staphylococcus aureus (1×105 cfu/ml) was assessed at two different temperatures of 25 °C and 35°C in TSB. Then, samples from cocultures and control were pour plated in Baird Parker agar and MRS agar to compute the number of S. aureus and Lactobacillus paracasei at 0, 24, 48, 72 hours after incubation. Then, enterotoxin production was evaluated by ELIZA rida screen kit. The data were investigated by ANOVA and K-square (chi-square) tests.

 Results: It was found that compared to controls, Lactobacillus paracasei inhibited the growth of Staphylococcus aureus and reduced the number of S. aureus cells about 3 logs in 25°C and 2 logs in 35°C. The production of A, C, and E enterotoxins was inhibited by S. aureus at a temperature of 25°C according to ELIZA rida screen test. The figure was 35°C for enterotoxins E and A.

 Conclusion: Probiotics can be used as a new approach for the biocontrol of S. aureus without using antibiotics.

 
Comparing The Effect Of Lactobacillus Aacidophilus And MRS Medium On Mesenchymal Stem Cells Proliferation
Mostafa Saberian , Elham Shahidi Delshad , Tahereh Naji , Ali Samadikuchaksaraei ,
Volume 9, Issue 3 (9-2015)
Abstract

Background and Aim: The use of probiotics has been surveyed in different studies. For example, many researches have been conducted on immunity, cancer and embryonic cells proliferation. Mesenchymal stem cells (MSCs) have a rather slower growth and a more limited number of passages. In this research, the effect of supernatant of Lactobacillus acidophilus (LS) as one of the most commonly used probiotics on the proliferation of mesenchymal stem cells has been studied with the aim of increasing their proliferation for the treatment of patients in need of transplantation using mesenchymal stem cells.

Materials and Methods: The MSCs separated from rats’ bone marrow were led to bone and fat levels in the second passage, and their mesenchymal state was confirmed. The cells were then treated by the supernatant of Lactobacillus acidophilus (LS) and MRS broth medium, which have been separated in advance. The number of cells was examined by MTT test equated with the standard.

Results: A curve was drawn for the cells’ growth in different amounts and the number of cells was obtained by converting the results of MTT test to a standard curve. For statistical analyses, SPSS and ANOVA were employed.

Conclusion: The findings show the double effect of LS on the weak effect of MRS broth medium. The use of supernatant of Lactobacillus acidophilus (LS) can be a practical and economical method for increasing the proliferation of MSCs isolated from bone marrow.


Apoptotic Induction in Human Colorectal Adenocarcinoma Cell Line and Growth Inhibition of Some Gastrointestinal Pathogenic Species by Lactobacillus Sakei Metabolites
Mohammad Saber Malaki, Leila Rouhi, Khalil Khashei Varnamkhasti,
Volume 14, Issue 6 (1-2021)
Abstract
Background and Aim: Lactobacillus is the most important genus of lactic acid bacteria and the use of some species of lactobacillus with the probiotic potential can be effective for inhibition of the growth of some pathogens and control of 
gastrointestinal diseases and cancers. In this study, the pro-apoptotic and antimicrobial effect of Lactobacillus sakei on human colorectal adenocarcinoma cell line and some gastrointestinal pathogenic species was examined. 
Materials and Methods: In this study, the antimicrobial activity of metabolites of Lactobacillus sakei was assessed by Well Diffusion Agar (WDA) method against some gastrointestinal pathogenic bacteria. HT-29 colorectal adenocarcinoma cancer cells were cultured in DMEM medium with 10% bovine serum. The cells were treated in 5, 10, 15 and 20 mg/ml concentrations of sakei metabolites and incubated at 24 and 48 hours. Apoptosis was analyzed by Annexin V-FITC/PI kit according to the manufacturers protocol in both incubation times. For error reduction, each test was performed in triplicate
Results: The results of this study indicate that sakei  was able to produce antimicrobial metabolites against gastrointestinal pathogenic bacteria. Also, the results of the Annexin test showed that with increasing concentration of sakei metabolites in dose dependent manner, induction of apoptosis in this cell line increases (P<0.05).
Conclusion: It seems that there is a good research field for the use of bioactive compounds produced by Lactobacillus sakei in the control of gastrointestinal pathogenic bacteria and treatment of human colorectal adenocarcinoma. 

The Molecular Isolation of the srf Gene from Thermophilic Soil Bacilli and Its Cloning in Susceptible Cells for Industry Use
Maryam Poormehdi, Nooshin Khandandezfully, Kumarss Amini,
Volume 18, Issue 3 (7-2024)
Abstract
Background and Aim: Thermophilic bacillus is a type of thermophilic bacillus, carries various genes and biosurfactants, microbial surfactants are surface active molecules produced by various microorganisms such as bacteria, yeasts and filamentous fungi. Biosurfactants are able to reduce the surface energy between phases and create electrostatic barriers, thus preventing the integration of particles. The aim of the present study was the molecular isolation of the srf  gene from thermophilic soil bacilli and its cloning in susceptible cells for industry use.
Materials and Methods: Fifteen samples from different regions of Kerman were collected and screened to isolate Bacillus strains. Morphological and biochemical studies were done to identify the strains. After biochemical examination of isolated microbial isolates and confirmation of Bacillus strains, DNA extraction was done. Then, the srf  gene was identified by PCR method from these isolates. The amplified fragment was inserted into pTG19 vector by TA cloning method. Then, the recombinant vector was transformed into E.coli origami bacteria and cloning was confirmed using common methods. The housekeeping gene 16S rRNA was used as the internal control of the test. The analysis of the gene expression level was performed by measuring the relative expression of mRNA as compared to the negative control that E.coli bacteria lacked the srf gene.
Results:  A total of 12 isolates of thermophilic bacilli were obtained from soil samples. As result, the PCR reaction for the srf  gene with the designed primers was found to be positive in 1 isolate (8.3%). The presence of srf  gene and the expression of this gene were checked by real time PCR test. Examining the white and blue colonies, M13 primer, junction location and determination of the 16S rRNA gene sequence confirmed the correctness of the cloning of the mentioned gene in the host bacteria.
Conclusion: As a result of the present study, it was possible to identify the native thermophilic bacillus carrying the srf gene, which can be used to obtain biosurfactant enzyme widely, conveniently and economically, for use in industrial and agricultural purposes, removing oil pollutants and reducing environmental surface tension, etc. which can be advantages.

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