نشریه بیولوژی کاربردی
سال دهم شماره 2 (پیاپی 38، تابستان 1399)

Microalgae are single-celled algae that have favorable environmental conditions such as temperature and long period of light as well as nutrients containing phosphorus and nitrate affect their abundance and distribution and sometimes cause health, environmental and process problems in water plant.

This study was carried out to determine the density and diversity of microalgae in the water of 15 Khordad Dam in two winter and spring seasons, in different areas of the dam at a height of one and five meters by sampling and identifying and counting based on algae morphology.

The results show that diatoms with (41.1%), binary algae with (32.5%), green algae with (23.2%) and green-blue algae with (41.1%) different microalgae. (3.2%) constitute the most dominant communities, respectively. In the samples taken from the entire dam, the dominant genus is Peridinium algae. The highest frequency was at one meter height in June and on the west side and the lowest frequency at five meters height was in December and on the east side (p < 0.05).

The results of this study will be effective in planning the operation management of different water treatment plants in Qom.

In this research, nanoparticles were synthesized by two methods of hemolipation and precipitation-reduction under optimal conditions. Using X-Ray Diffraction and Fourier Infrared Spectroscopy (FTIR) tests, the optimal conditions for nanoparticle synthesis were determined by sediment-reduction method. Finally, by analyzing the images taken by electron microscopy from two samples, the average size of magnetite nanoparticles synthesized by co-precipitation method was measured at 39nm and by sediment-reduction method at 4/5nm. By plotting the particle size distribution, in the co-precipitation method, the particle size distribution of nanoparticles was relatively wide and in the sediment-reduction method, the relatively narrow particle size distribution was obtained. Finally, by comparing the average size, distribution, particle size and morphology of nanoparticles synthesized by the two methods mentioned, magnetite nanoparticles synthesized by sediment-reduction method are proposed for drug delivery applications.

This is a research study involving experiments and reviewing library studies on controlled drug delivery systems. After conducting library studies and obtaining sufficient information, laboratory tests of this study were performed.

With the creation of particle systems, new properties were introduced into drugs that did not exist before. The use of nanoparticles has led to its optimization and has created features such as therapeutic target, improved cell permeability, longer life, etc. that were not previously available in conventional drugs. Nanoparticles synthesized by the deposition-reduction method, which are more synthetic than the co-precipitation method, have a higher purity, a much smaller particle size, and a narrower particle size distribution. Due to the fact that magnetite nanoparticles in sizes below 15 nm show the properties of paramagnetic cloud and also nanoparticles suitable for pharmaceutical applications should have a uniform distribution of particle size, nanoparticles synthesized by sediment-reduction method are recommended for drug delivery applications.

Due to the fact that magnetite nanoparticles in sizes below 15 nm show superparamagnetic properties and also nanoparticles suitable for pharmaceutical applications should have a uniform distribution of particle size, nanoparticles synthesized by sedimentary-reduction method for drug delivery applications are recommended.

Methicillin Resistant-Staphylococcus aureus (MRSA) has been introduced as important factor in Hospital-Acquired Infections (HAI). Diversity in Staphylococcus strains can affect the response to treatment and identifying of strains can be effective in the selection of antibiotics. The aim of this study was to determine the genetic diversity of MRSA isolates with random primers.

This cross-sectional descriptive study was performed in 2015 on 50 MRSA isolates of clinical skin samples. Genomes were extracted by Boiling method. RAPD-PCR method was performed by 16 random primers. To investigate the genetic similarity, matrix 1/0, NTSYS and MVSP software's were used. One-dimensional clustering and ordinations were conducted.

The highest and lowest produced bonds related to M4 and M9 primers respectively. The greatest mean produced bands for each isolate/primer up to 8.1 relates to M4 primer. The most polymorphic bands, 36 bands belonged to M5 primer. The heaviest band, 3.6 Kb produced by M2 primer and the lightest band, 100 bp produced by M12 primer. A total of 16 primers, 583 bands formed that were 412 (70.91%) polymorphic bands and 171 (29.09%) specific bands. RAPD-PCR divided isolates into two clusters.

This study showed that these isolates are very heterogeneous genetically. RAPD-PCR is important in rapid detection of an epidemic outbreak, tracing the origin of the infection and the subsequent managing of infection control. Therefore, the present study tries to develop this approach and apply it in health management by providing information about the genetic diversity of MRSA.

Gram-negative bacilli are important hospital pathogens with an increasing prevalence of broad-spectrum beta-lactamase genes and integrons. Therefore, identification of these antibiotic resistance genes is essential to prevent the spread of resistant strains.The aim of this study was to determine the frequency of class 1, 2 and 3 integrons and bla-CTX-M, bla-SHV and bla-TEM broad-spectrum beta-lactamases genes in Gram-negative bacilli isolated from Bandar Abbas Pediatric Hospital.

Sixty Gram-negative bacilli strains were isolated from clinical specimens and identified by biochemical tests and their antibiotic resistance patterns were determined by Disk Diffusion method. Multiplex PCR was used for detection of class 1, 2 and 3 integronsand PCR wasperformed to identify the bla-CTX-M, bla-SHV and bla-TEM family’s genes, respectively.

The most frequent strains belonged to Escherichia coli 70% and the highest resistance and sensitivity were Sulfomethoxazole 68% and Gentamicin 75% respectively.Of the 60 strains isolated, 61.7% and 26.7% had Class I and 2 integron genes, respectively, whereas no class 3 integron gene was detected in any of the isolates. PCR results showed that blaCTX-M, blaSHV and blaTEM family genes were 66.7%, 10% and 31. 7% strains, respectively.

In this study, there was a significant correlation (p < 0.05) between the presence of class 1 and 2 integrons, bla-CTX-M, bla-SHV and bla-TEMand antibiotic resistance. Therefore, determination of antibiotic resistance genes and the use of appropriate therapeutic methods based on antibiogram pattern determination of the strains are also suggested.

Salmonella is a Gram-negative intestinal organism and causes food poisoning in human. Salmonella has five virulence genes, stn, Phop/Q, spvc, slyA and sopB. These genes encode proteins in different parts of the bacteria that can confront with immune system, and the complement system and can cause death in the cell. The aim of this study was to detect slyA, stn, sopB, Phop/Q and spvc genes in Salmonella typhimurium strains isolated from clinical samples by the multiplex PCR method and to determine antibiotic resistance patterns.

In this descriptive cross-sectional study, in 2016, 60 stool samples in order to identify Salmonella typhimurium from Alborz-Karaj Hospital were collected. After confirmation of the strains by using standard biochemical and microbiological tests, an antibiotic susceptibility test was performed on a Muller Hinton Agar medium and based on Clinical and Laboratory Standards Institute (CLSI) guidelines. Multiplex PCR assay was performed to detect virulence genes using specific primers.

The results of the antibiotic susceptibility test showed that all isolates were sensitive to imipenem, gentamicin and amikacin. Also, molecular findings showed that the prevalence rates of Phop/Q, slyA and stn genes were 100%, 98.3%, and 91.6%, respectively. While sopB and Spvc genes were not observed in isolates of Salmonella typhimurium.

The results of this study indicate that the prevalence of virulence genes in clinical Salmonella typhimurium isolates can serve as an alarm for the prevalence of these genes to the other Salmonella serotypes.

The study of microorganisms in specific regions with specific characteristics has long been important. Howz Soltan is a salt lake in the central desert zone of Iran, which is considered as an area of great salinity. The present study was conducted to isolate halophilic bacteria from Howz Soltan lake in order to achieve maximum information concerning to microbial diversity of the lake.

For this purpose, samples were collected from five regions. Then the samples were diluted and cultivated on Molten haloid agar with different salt concentrations (5-35%). The plates were incubated at 37ºC in aerobic conditions. Biochemical characterizations, utilization of carbon sources and production of exoenzymes were investigated.

In total 205 different colonies were grew on medium with 5-35% salt concentrations. Of all isolates 18 strains were grew on medium with 15-35% salt concentrations. These strains were considered extreme halophilic bacteria and the rest were halotolerant and moderate halophilic bacteria. The results obtained from microscopic analysis of the isolates indicated that 178 isolates were gram positive bacilli, cocci and filamentous and 27 isolates were gram negative with bacilli shape. Phenotypic identification recognized that the isolated strains of extreme halophilic bacteria were Halobacterium ,Haloarcula ,Halorubrum and Halococcus. In addition, enzyme production assay of these strains showed some of them have capability to produce different enzymes viz., amylase, lipase, protease, DNase, urease, xylanase and gelatinase.

In general, our finding showed the huge diversity of halophilic bacteria in Howz Soltan lake. Furthermore, these bacteria could be considered as sources of halotolerant enzymes in different industries.