فهرست مطالب سیدجمال هاشمی هزاوه

Background of the study:

 In the cultured and ornamental fish industry, fungal organisms threaten young and adult cultured populations and lead to the decay of eggs and larvae. Fungal Infections Secondary infections in fish are caused by primary parasitic, viral and bacterial organisms.

In this research, the number of fungal infections and their type of infection in ornamental fish should be determined.

This study was conducted on ornamental fish with clinical symptoms. The samples were obtained from different places. After identifying the fungi, their abundance was checked by culture and PCR.

Out of the total of investigated cases, the skin and gills had lesions in cases, and the result of mushroom culture was positive. In the PCR analysis of these samples, the fungal species identified by gene sequence were Cladosporium, Candida, Penicillium, and Aureobasidium pullulans and Rhodotorula yeast. Pathological lesions in the gills were dark and hyperemic; under the microscope, epithelial cells were shed, and leukocytes were present. It was seen in the skin as macroscopic and microscopic wounds. Finally, these fungi are responsible for forming lesions seen under certain conditions, such as environmental instability and immunosuppressive factors.

Aspergillosis is an opportunistic fungal infection in animals. The disease is mainly respiratory, but other disease manifestations also occur in poultry. Researchers have shown that, one of the reasons for the increase in drug resistance in Aspergillus species is the overexpression of the CYP51A gene. This study compared CYP51A gene expression of Aspergillus fumigatus isolated from poultry against fluconazole and nano-fluconazole. Fluconazole liposomal-nanoparticles were prepared by the thin layer hydration method. We dissolved 5.12 mg of fluconazole powder in 1 ml of sterile distilled water and 6 ml of chloroform-methanol organic solvent. We added 51 mg of lecithin and 5 mg of cholesterol to it. The size of nanoparticles was 88.9±12.1 nm and the surface charge of these nanoparticles was -20.12±1.88 mv. We also used a Scanning-Electron Microscope to study the structure of nanoparticles. Thirty samples of A. fumigatus were collected from poultry lung nodules. Minimum inhibitory concentration (MIC) was performed by standard Broth Microdilution method according to NCCLS-M38A2 to evaluate the MIC of fluconazole and nano-fluconazole against isolates. We selected two high-resistance isolates to fluconazole and used them to determine the CYP51A gene expression level by real-time PCR. The results showed that nano-fluconazole had a lower MIC than fluconazole and in lower concentrations of the drug inhibited the growth of Aspergillus fumigatus isolates. CYP51A gene expression was increased in fluconazole and nano-fluconazole-treated isolates compared to the untreated state. Conversely, a decrease in CYP51A gene expression was observed in the exposure to nano-drug compared with the normal drug.

Epidermophyton floccosum is one of the worldwide anthropophilic dermatophytes that invade keratinized structures such as hair, skin, and nail, causing dermatophytosis by secreting important proteases such as subtilisin. This study aimed to evaluate the presence of SUB3 and SUB6 encoding serine proteases in the isolate, which received from the fungi culture collection of Tehran University of Medical Sciences, Faculty of Public Health. Special primers designed according to the highly conserved regions of similar genes in other dermatophytes. Genomic DNA and designed primers used in PCR, then PCR products sequenced with ABI PRISM®3730XL automated Sanger sequencer, and presence of 2 new subtilisin genes (SUB3 and SUB6) were confirmed and recorded in NCBI(with the accession numbers MN206114, MN177931 respectively). The coding sequence of SUB3 found to contain 861 nucleotides, which encodes a polypeptide with 287 amino acids. The coding sequence of SUB6 found to contain 699 nucleotides that encode a polypeptide with 233amino acids. Comparing the sequences with Gene Bank database information, revealed significant homology with other dermatophytes. Achieving a better understanding of the molecular characteristics of virulence genes may help develop effective therapies and prevention strategies.

In this research, using FRET (fluorescence resonance energy transfer) from Cd/Te quantum dot (anti Ochratoxin A antibody immobilized on the external surface of quantum dot or QDs) to (Ochratoxin A labeled with Rhodamine 123 bound to albumin), a sensitive competitive immunoassay was developed for measuring Ochratoxin A. The highly specific immune-reaction between anti-Ochratoxin A antibody on the QDs and labeled Ochratoxin A brings the Rho fluorophore and the QDs in close spatial proximity, and following photo-excitation of the QDs, causes FRET to occur between the Rho fluorophore (acting as the acceptor) and the QDs (acting as the donor). In the absence of free Ochratoxin A, the immune reaction between labeled Ochratoxin and the anti-Ochratoxin antibody on the QDs induces emission and causes FRET to occur. In the presence of free Ochratoxin A, it competes with the labeled Ochratoxin A-albumin complex for binding to the antibody-QDs conjugate in the Nanobiosensor, leading to reduction in Rhodamine emission after FRET. The reduction in the fluorescence intensity of the Rhodamine acceptor directly correlates with the concentration of free Ochratoxin A in the sample. This method has a detection limit of 220pg per ml. It has also been used to measure Ochratoxin A in human serum samples. A linear relationship is found between the increase in the fluorescence intensity of Rho 123 at580 nm and the concentration of OTA in spiked samples over the 100-800 pg⋅mL−1 concentration range. This highly sensitive homogeneous competitive detection scheme is simple, rapid and efficient. It does not require multiple separation steps and excessive washing.

Soil bacteria، particularly Bacillus genus have the potential of producing a range of bioactive substances with antimicrobial and antifungal properties. They have the ability to produce hundreds of active and effective biologic compound against microorganisms. Therefore، it seems to be a proper candidate in the biocontrol of fungal pathogenesis. In this study، soil samples were collected from different parts of Gorgan in order to isolate Bacillus and to determine their antifungal activity against T. mentagrophytes. The Isolates that had the highest antifungal effects were analyzed by PCR and 16s rRNA sequencing. of 54 strains، 14 have antifungal activity. The Isolates، S4 and S12، identified as B. cereus and B. thuringiensis respectively show the highest antidermatofit effect. These isolates based on 16s rRNA sequence analysis show 97% homology with Bacillus cereusstrain KU4 and Bacillus thuringiensisstrain ucsc27. According to the results، it seems that the soil Bacilli have biocontrol potential against dermatophytic agents such as T. mentagrophytes.