Showing 7 results for Gozari
Ramin Karim Zadeh, Amir Houshang Bahri, Mohsen Gozari,
Volume 6, Issue 3 (winter 2016)
Abstract
In this research antibacterial activity of Pseudomonas isolates derived from hepatopancreas of Litopenaeus vannamei were evaluated against pathogenic Vibrio spp. Shrimp samples collected from 9 different ponds in Tiab region- Hormozgan province. Hepatopancreas samples of collected shrimps were inoculated in three different isolation media. Pseudomonas Isolation Agar medium revealed highest yield by isolation of an average 22 pseudomonas isolates. Approximately 40 Pseudomonas isolates were obtained. Results of antibacterial screening experiments by well diffusion method demonstrated antibacterial activity of MR21 and MR35 strains. These producer isolates exhibited the highest antibacterial activity against all target Vibrio species consist of Vibrio parahaemolyticus, V. harveyi, V. anguillarum and V. alginolyticus after 72 hours. Biochemical, morphological and physiological studies showed that MR21 and MR35 strains belong to Pseudomonas aeruginosa. Evaluation of antibacterial activity of potent strains in different media proposed trypticase soy broth as an efficient medium. Assessment of temperature influence on antibacterial activity of potent isolates revealed stability of antibacterial activity in 25˚c, 35˚c, 45˚c. Comparison of antibacterial activity of producer strains in presence of seawater and distilled water showed that seawater could promote antibacterial activity. Analysis of growth curve revealed that potent isolates entered to stationary phase after 24 hours. According to achieved results P. aeruginosa MR35 and P. aeruginosa MR21 can considered as potential probiotic isolates for further studies.
Mahsa Alirezaeinejad, Hossein Parvaresh, Mohsen Gozari,
Volume 6, Issue 4 (Spring 2017)
Abstract
This study was conducted to determine the original indicator of microbial pollution (Escherichia coli) in the major swimming areas of Bandar Abbas. Three major swimming areas were selected in Bandar Abbas that included Soroo, Khaje Ata and Ghadir Park. During the present study, 30 sea water samples were gathered to evaluate the important indicator of microbial contamination and parameters such as pH, salinity was studied in autumn and winter 2015. Results showed that the mean of microbial pollution in swimming areas of Soroo, Khaje Ata and Ghadir Park in autumn was 770, 678.1 and 468.7 MPN/100 ml respectively, and in winter 537.2, 500.6 and 374 MPN/100 ml respectively that all results of microbial pollution were higher than national and global standards. The changes of microbial pollution and physical- chemical parameters were not significant in the two seasons. But the microbial pollution values of Escherichia coli in third stations were significantly decreased in comparison to seaside stations.
Mohammad Reza Sadeghi, Saeid Tamadoni Jahromi, Amir Houshang Bahri, Mohsen Gozari,
Volume 7, Issue 2 (Autumn 2017)
Abstract
In this research Vibrio harveyi strains were isolated and identified from hepatopancreas of Litopenaeus vannamei from Tiab region, Hormozgan province. Shrimps samples were collected from five different ponds in northern and southern Tiab shrimp culture sites. Isolation phase was performed by dilution and inoculation of hepatopancreas samples on thiosulfate citrate bile salts sucrose agar medium. Purified isolates were identified phenotypically based on morphological, biochemical and physiological methods. Genomic DNA of five selected Vibrio harveyi strains were extracted and their 16S rRNA genes were amplified. Comparison of amplified 1000 bp sequence of 16srRNA genes with registered sequences in NCBI gene bank by megablast software exhibited high homology between isolated strains and Vibrio harveyi ATCC BAA-1116. Phylogenetic analysis by MEGA 6 sofware based on neighbour Joining method showed that isolated strains had similar monophyletic origin. According to these results presence of V. harveyi strains in hepatopancreas of Litopenaeus vannamei from Tiab region were genetically confirmed.
Dr Mohsen Gozari, Dr Nima Bahador, Dr Amir Reza Jassbi, Dr Mohammad Sedigh Mortazavi, Dr Ebrahim Eftekhar,
Volume 7, Issue 4 (Spring 2018)
Abstract
Screening bacteria for bioactive compounds is the first step in the drug discovery programs. The aim of the present research was to achieve cytotoxic and antioxidant metabolites from actinobacteria of Persian Gulf sediments and to investigate the effects of combinations of seven treatments and six isolation media on the selective isolation process. A total of 395 actinobacterial isolates were collected from 12 sediment samples. Heat treatment and M6 medium were exhibited maximum efficiency of 34.59% and 32.82% isolation, respectively. Preliminary characterization results revealed the dominant distribution of Streptomyces like isolates in all investigated stations. Streptomyces isolates distribution followed a depth dependent frequency pattern. Approximately, 27.45% of the examined isolates could scavenge 90% of DPPH radicals in 1250 µg/ml final concentration. Exudated metabolites of potent isolates could scavenge DPPH radicals with IC50 ranges from 411 to 670 µg/ml. The results of cytotoxic activity showed that 54.9% of examined isolates exhibited LC50 lower than 1000µg/mL against Artemia cells. Extracted metabolites from 12 potent isolates exhibited LC50 range from 236.3 to 565.3 µg/ml. These results suggest the widespread distribution of the antioxidant and cytotoxic producing actinobacteria in Persian Gulf sediments and represent actinobacterial isolates as promising candidates for the discovery of microbial derived bioactive compounds.
Mohsen Gozari, Mahmoud Hafezieh, Saeid Tamadoni Jahromi, Sajjad Pourmozaffar, Yazdan Moradi,
Volume 10, Issue 3 (Winter 2020)
Abstract
Melanosis is a major problem in the marine crustaceans processing industry particularly on shrimps which can lead to financial loss to producers. The cause of this complication is biochemical reactions of polyphenoloxidase (PPO) enzyme and the formation of the dark pigments on shrimp′s body. The main purpose of the present study was to evaluate the inhibitory effect of secondary metabolites extracted from SC 190 on PPO activity to achieve a potential alternative for chemical inhibitors implemented for control of melanosis on Pacific white shrimp. In this study, the PPO enzyme was extracted from the cephalothorax of shrimp samples and partially purified. The results showed that extracted metabolites from the strain SC 190 isolated from sea cucumber Holothuria scabra represented inhibitory activity on the PPO enzyme with an IC50 value of 60.69 ± 3.76 µg/mL. The bacterial extracted metabolites could scavenge DPPH free radicals with an IC50 value of 45.10±2.14 µg/mL. The result of the toxicity test showed that the extracted metabolites were not toxic to the human umbilical vein endothelial cell lines. Chemical screening approved the existence of phenolic compounds in the extracted bacterial metabolites. Polyphasic identification of SC 190 isolate revealed that it has belonged to Streptomyces genus and its 16S rRNA gene sequence had 99% homology with S. cellulosae. According to the results, the metabolites extracted from Streptomyces sp. Strain SC 190 can be considered as a potential biopreservative in the preservation of Pacific white shrimp.
Mohsen Gozari, Saeid Tamadoni Jahromi, Eisa Abdolalian, Sajjad Pourmozaffar, Ramin Karimzadeh, Ahmad Zaheri, Maryam Moezzi,
Volume 11, Issue 2 (Autumn 2021)
Abstract
Biological control using marine bacteria is part of the integrated management to control harmful algal blooms (HABs). The aim of the present study was to investigate the frequency and diversity of bacteria in HAB-exposed regions in Hormozgan province and to evaluate their algicidal activity against Cochlodinium polykrikoides. Seasonal frequency of bacteria in 10 stations throughout the coastal regions of Hormuz Island, Bandar Abbas, and Bandar Lengeh showed maximum frequency in St 1, St 6, and St 10 in spring. We identified 10 bacterial families in sediment samples, which dominantly belonged to Vibrionaceae, Entrobacteriaceae and Pseudomonadaceae with 29%, 14 %, and 12% frequency, respectively. While in seawater samples Entrobacteriaceae and Vibrionaceae were dominated with 23% among 6 identified families. Approximately, 13.33% of sediment-isolated bacteria and 9.09% of seawater-isolated bacteria were able to kill whole algal cells. The extracted metabolites of the active isolates exhibited significant algicidal activity with LC50 values ranging from 90.28±3.14 to 1029±45.94 µg/ml. This study presented an overview of the frequency and diversity of bacteria in the investigated areas and provided eight algicidal isolates for future studies on the biological control of HABs.
Zeynab Chatrrooz, Iman Sourinejad, Mohsen Gozari,
Volume 14, Issue 1 (Spring 2024)
Abstract
The objective of this study was to assess the impact of a native probiotic product on the intestinal bacteria biodiversity of Penaeus vannamei. Shrimp larvae were administered the probiotic via food (treatment 1), through culture water (treatment 2), and a control group received no probiotics (treatment 3). After three months of rearing, bacteria were isolated from the shrimp intestines, and initial identification was conducted based on morphological, biochemical, and physiological traits. The diversity of intestinal bacterial flora was assessed using PCR-RFLP methods, focusing on the determination of 16S rRNA gene sequences. Results revealed a significantly higher abundance of cultivable bacteria in the intestines of shrimp from treatment 1 (2.4 x 107 CFU/gr) compared to those receiving probiotics through water (6.16 x 106 CFU/gr). The probiotic product led to a reduction in bacterial diversity in the intestines of treated shrimp, decreasing from 10 to 6 genera. Additionally, the frequency of Vibrio bacteria decreased by 20%, while other opportunistic pathogenic bacteria such as Pseudomonas, Aeromonas, Shewanella, and Photobacterium were eliminated. Overall, the findings suggest that administering probiotics through food was more effective in modulating the diversity of the shrimp intestinal microbiome. This study enhances our understanding of the impact of indigenous probiotics on the composition and dynamics of the intestinal microbiome of P. vannamei.
