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Background and objectives:  Safety is a key criterion for assessment of probiotics. The objective of this study was to evaluate safety of a new Iranian Lactobacillus paracasei IBRC-M 11110 strain as a candidate probiotic. 
Methods: Eighteen male and 18 female Wistar rats were divided into two experimental and a control group. The experimental groups received the bacterium at two doses of 6 × 10⁸ CFU/day and 6× 10⁹ CFU/day for 28 days through oral gavage. The control groups received normal saline. On day 29, blood, serum and tissue samples were taken for analysis.
Results: Administration of the bacterium did not affect the general health and body weight of the rats during the study period. No significant change was observed in the blood parameters of rats in the experimental groups except for a significant decrease in mean corpuscular volume and mean corpuscular hemoglobin of male rats. Serum analysis showed a significant increase in the alanine transaminase and a significant decrease in aspartate transaminase in the experimental groups of male and female rats, respectively. In both male and female rats, a significant decrease in urea and a significant increase in creatinine were observed in the experimental groups. However, the above parameters were all within the normal range. Histopathological analysis of liver and kidney tissues also showed no abnormality.
Conclusion: The results confirm that L. paracasei IBRC-M 11110 was safe in the subacute toxicity test in Wistar rats.

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Background and objectives: Cutaneous leishmaniasis is endemic in most areas of Iran, and the diagnosis of its species is essential for controlling the disease. Leishmania major is the causative agent for cutaneous leishmaniasis in humans. Molecular methods are generally more sensitive than microscopic methods. The present study aimed to use a polymerase chain reaction-enzyme linked immunosorbent assay (PCR-ELISA) technique for detecting live L. major from wounds of patients with cutaneous leishmaniasis.
Methods: In the present study, a standard strain of L. major promastigotes was used as the positive control for purification of DNA. The Novy–MacNeal–Nicolle and RPMI-1640 media were used for reproduction of parasites. DNA was isolated from specimens taken from 35 patients with suspected cutaneous leishmaniasis whose disease was confirmed by direct smear method. The PCR-ELISA technique was later applied by using the standard strain, patient specimens, and primers specific for the 18s rRNA.
Results: Out of 35 patients, 17 (48.6%) were male and 18 (51.4%) were female. In addition, 8.6% of the patients lived in the Gonbad-e Kavus County, while all patients had been infected in villages around Gonbad-e Kavus. Of 35 patients with confirmed cutaneous leishmaniasis according to the direct smear method, 31 patients (86.31%) had leishmaniasis based on the PCR method and the PCR-ELISA methods.
Conclusion: Based on the results, the PCR-ELISA method is more sensitive and accurate for detecting L. major.

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Background and objectives: Bacteriocins are generally active antimicrobial peptides effective against bacteria closely related to the producer. Escherichia coli produce two bacteriocins: colicins and microcins. Microcin J25 (Mcc J25) is an antibacterial peptide that inhibits bacterial transcription by disrupting the nucleotide-uptake channel of bacterial RNA polymerase. The objective of this study was to evaluate antimicrobial activity of MccJ25 produced by the bacteriocinogenic E. coli.
Methods: In this experimental study, 120 clinical specimens were selected from private diagnostic laboratories in Isfahan (Iran) in 2020. Antagonistic activity of isolates was tested by adopting agar plug method. Total DNA was extracted from clinical specimens and polymerase chain reaction (PCR) was performed using specific primers for amplification of the complete sequence of MccJ25 gene. Accuracy of the PCR products was confirmed by direct sequencing. Homology analysis was performed by using BLAST. Data were analyzed with Chromasv2.1.1 software.
Results: Overall, 120 E. coli strains were isolated from the clinical specimens. The antibiotic activity of Mcc J25 was mainly directed at Enterobacteriaceae, including several pathogenic E. coli strains of which 25 had positive well test samples, and about 5 (20%) of the collected clinical samples that were infected with E. coli had the MccJ25 gene.
Conclusions: Based on the results, Mcc J25 has favorable antibacterial potential, which can be further exploited as an alternative to chemical antibiotics.

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Background: Certain trace elements, like cerium, have the potential to disrupt iron metabolism. This study explored the impact of cerium on intestinal iron absorption, focusing on the initial stage of iron metabolism. We employed the rat everted gut sac (EGS) segments to assess the interference caused by cerium. The primary objectives of this study were to examine the absorption of cerium in the intestines and to compare iron absorption in the presence and absence of cerium.
Methods: For the EGS experiment, segments of the rat's duodenum, ileum, or jejunum were promptly excised, cut into 5-6 cm segments, and rinsed with a physiological solution. These freshly prepared rat EGS segments were then incubated in Earle's medium containing iron (III) and/or cerium (III). We examined the impact of ascorbic acid, glucose, and different time intervals on the intestinal absorption of cerium and iron. Specifically, we investigated how glucose (5 mM) and ascorbic acid (2.8 mM) affected the absorption of cerium and iron at various concentrations (ranging from 0 to 200 mg/L). Additionally, we assessed the interfering effect of cerium on iron absorption.
Results: The results indicated that the maximum intestinal absorption of Fe (III) and Ce (III) occurred at a concentration of 200 mg/L. Furthermore, it was observed that their uptake increased following the reduction by ascorbic acid. The absorption of these elements also rose in the presence of glucose, suggesting energy-dependent transport. Additionally, a consistent cerium concentration was found to decrease iron absorption by 24.3% (P ≤ 0.05).
Conclusion: Based on the results, cerium likely reduces iron uptake by competing with iron. Cerium can also disrupt iron metabolism and lead to iron-related metabolic disorders. However, further studies at the molecular and intracellular levels are needed to gain a better understanding of this mechanism.
 

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Background: Ulcerative colitis (UC) is a long-term inflammatory bowel disease (IBD) caused by abnormal immune responses, leading to inflammation and scarring in the large intestine. The bacteria Prevotella melaninogenica, found in the intestine and mouth, may contribute to UC. This study focuses on the detection of P. melaninogenica in the saliva of UC patients and compares them with the healthy control (HC) group.
Methods: The present study was a case-control study including 40 UC patients and 40 healthy controls (HCs) with an average age of 43.0 3± 10.3. This study used a real-time PCR test to investigate the frequency and average number of P. melaninogenica from the 16S rRNA gene sequence of P. melaninogenica in both groups.
Results: P. melaninogenica was more frequent in UC patients (77.5%) than HCs (45%) (p = 0.003). The patient group had more bacteria (339.31 ± 1082.29) than HCs (61.29 ± 154.03) (p = 0.005). Women in the UC group had more P. melaninogenica (492.35 ± 1427.61) than the control group (56.98 ± 123.50) (p = 0.0342). Similarly, men in the UC group (262.85 ± 664.97) had more bacteria than the control group (72.62 ± 222.76) (p = 0.015).
Conclusion: The current study showed that dysbiosis in P. melaninogenica, a bacterium in human saliva, could be important in the development of UC. Further investigation is needed to evaluate its use as a potential biomarker in the UC.