جستجوی مقالات مرتبط با کلیدواژه « آب دریا » در نشریات گروه « پزشکی »

The use of Spirulina platensis has been expanded in various fields. The main goal of this research is to optimize the growth conditions of this microalgae to reduce costs and increase the benefits of its mass production in seawater. It is also feasible to lessen environmental pollution by producing more spirulina by discovering the best growing conditions for it through the enrichment of Persian Gulf water.

First, the growth conditions of Spirulina platensis were optimized based on three factors: temperature, light, and pH. The temperature factor included four treatments, the light factor included four treatments, and the PH factor included five treatments. Also, Spirulina platensis microalgae were cultured in optimal growth conditions in Persian Gulf water, seawater enriched with 5% Zarrouk, 10% Zarrouk, with urea, and pure Zarrouk culture medium.

The best temperature range for the growth of Spirulina platensis was 27–32 degrees Celsius. Also, the best growth was achieved in 16 hours of light and 8 hours of darkness; for the PH factor, the most appropriate value was determined between 10.72 and 11.47. Also, in the cultivation of Spirulina platensis, optimal conditions for the growth of Spirulina microalgae were obtained in the medium of Zarrouk, urea, 10% Zarrouk, 5% Zarrouk, and seawater, respectively.

Therefore, the growth of Spirulina platensis in Persian Gulf water is slow and shows little performance, and by enriching this water with the mentioned factors, the microalgae enter the logarithmic phase faster and show better performance.

Microplastics, as emerging and persistent pollutants, are ubiquitous in different environmental compartments and could be considered an ecological threat to wildlife and humans.

In the present review article, the existing studies on the presence of microplastics in water, sediments, and aquatic organisms of the Persian Gulf were reviewed with regard to different sampling techniques, samples preparation, and identification methods. 

The results indicated that the contributions of various countries to microplastics pollution of the Persian Gulf were different. The findings from the Iranian side of the Persian Gulf (especially for coastal sediments) showed higher pollution than its Arabian side. Blue and black fibers were the most predominant types of microplastics in the Persian Gulf. Based on the results, low density microplastics were more dominant in the water column, while high-density plastics were mostly found in sediments. The predominant types of microplastics in marine organisms were related to their habitats.

Microplastics contamination is a severe threat to the Persian Gulf’s environment. However, the lack of harmonized procedure for microplastics sampling, preparation, analysis, and report makes the comparison of different studies challenging. For instance, four studies reported the level of microplastics in seawater of the Persian Gulf with three different units. Hence, we suggest all studies use the same methodologies in the Persian Gulf to increase the comparability of the results.

Marine microorganisms have an astonishing potential for producing antimicrobial substances against pathogenic bacteria. In this study, isolation and measurement of antimicrobial activity among these microorganisms against some pathogenic bacteria was carried out.
Samples were collected in autumn from the west of the Caspian Sea. Isolated samples were purified and antimicrobial activity among these samples against some pathogenic bacteria were measured by the use of two methods. At the end, genetic substance (DNA) of the strains with antimicrobial effect against pathogenic bacteria was extracted and polymerase chain reaction with universal primers was carried out. Isolated strains were identified by molecular method (16SrDNA PCR sequencing) and the strains were submitted and registered as new marine strains in the NCBI.
Results showed, the strains with antimicrobial activity had a noticeable effect on gram positive bacteria. So that gram positive bacteria were nearly inhibited in all cases but antimicrobial activity was restricted against gram negative bacteria, because gram negative bacteria were inhibited only in few cases. Finally, identification of stains with antimicrobial effect showed, the strains belong to Bacillus genus.
According to this result; we can use marine bacteria for controlling growth of pathogenic bacteria that are resistant to drugs and as a big threat for the human health. Also we can optimize conditions for producing antimicrobial substances among them and we can extract them in industrial conditions for increasing quality and quantity antimicrobial substances in these bacteria for the use in different industries such as pharmaceutical industry.

This paper, discussed the concentrations of heavy metals such as cadmium, copper, lead, zinc, nickel, chromium, iron, and magnesium in surface sediments of the Gulf of Chabahar. Samples of coastal sediment and shallow waters were collected from five different stations in summer and winter, 2013. The research found that the concentrations of heavy metals in sediments is more than water, although the concentrations of metals in sediment and water from different stations followed a general trend. Seasonal variation had effect on the concentration of metals, so that in winter, the concentration of heavy metals such as copper, lead, zinc, cadmium, and nickel was more than of the summer season. Generally, concentration of heavy metals in the study area was less than the quality guidelines for sediments and water. However, between different stations, higher concentrations of heavy metals were found in stations nearby the fishing ports. The results show that increase in the concentrations of heavy metals can contribute considerable impacts on the pollution level due to fishing boats in the study area; although some metals are also of natural origin.

Vibrio spp are halophilic bacteria that predominantly reside in lakes and marines. Some species are responsible intestinal diseases and extra – intestinal complications. In this study, the occurance of Vibrio spp in the sea waters of Golestan province was investigated. For primary isolation, sea water samples were transfered into APW and TCBS agar media. Following primary isolation, species identification was performed by biochemical tests. A total of 7 different vibrio species were isolated from sea water which included V.vulnificus, V.Parahaemolyticus, V.alginolyticus, V.fischeri. V.natriegens, V.harveyi and V.damsela. The reason of different isolated vibrio to isolated selective samples was more than one and sometimes more colony on TCBS environment. Actually one sea water sample from each culture, several vibrio species were selected by biochemical tests.