JOURNAL OF MARINE BIOLOGY
Year:2019 | Volume:10 | Issue:40|Papers Count:8

Microalgae are valuable sources of secondary metabolites with diverse biological activity. Among the different bioactive compounds, alkaloids due to the unique medicinal properties have attracted much attention. There are different methods to determine the presence of alkaloids in natural resources. The aim of this study was to compare the sensitivity of Meyer and Wagner methods with the bromocresol green method in the early detection of alkaloids in the microalgae. For this purpose, in 2018, the methanol extract of Spirulina platensis was prepared. Using two standard methods (Mayer and Wagner) and bromocresol green colorimetric method, the presence of alkaloids in Spirulina was investigated. Next, thin layer chromatography (TLC) was performed to confirm the presence of the alkaloid. Total alkaloid content was also measured using the acid– base titration procedure. Evaluation result of methanol extract of Spirulina for the presence of alkaloids by the standard reagents was negative. But bromocresol green method and TLC showed the presence of alkaloids in this microalgae. The total alkaloid content was 11. 4 mg/g dry weight. Overall, this study showed that bromocresol green method is a better detection method of alkaloids in the microalgae biomass because of the simplicity, lack of requirement of expensive equipments, particularly high sensitivity.

The main objective of the present study was to investigate the changes in length, weight, condition factor (CF) and relative condition factor (Krel) of Rutilus kutum in different seasons and depths in the eastern coasts of the Caspian Sea (Goharbaran region In this study, three fishing methods, including small mesh size beach seine, gillnet and commercial beach seine were used during January 2014 to July 2014. The results showed that the slope (b value) of the length-weight relation was 3. 0003 which was not significantly different from 3 methods (P>0. 05), indicating isometric growth. Small and large fish were caught in small mesh size beach seine and commercial beach seine, respectively. The average length and weight were significantly different among three fishing methods (P<0. 001). The average (± SD) CF of small mesh size beach seine, gillnet and commercial beach seine were calculated as 1. 30± 0. 20, 1. 38± 0. 17, 1. 29± 0. 13 and the Krel were recorded as 1. 30± 0. 19, 1. 37± 0. 17 and 1. 29± 0. 13, respectively. For both variables, there were significant differences among three fishing methods (P<0. 05). Also, the averages for CF and Krel were significantly different among the different length classes and seasons (P<0. 001). Based on the average Krel, it can be concluded that Rutilus kutum had a good feeding and growth conditions in the Goharabaran region.

Maroon Dam Lake is an area with a capacity of 1, 200 million mm3 of water and a length of 30 km that is located in the Zagros Mountain Valley, 19 kilometers northeast of Behbahan. This study was carried out from spring 2016 to winter 2017 in order to recognize qualitative and quantitative changes of phytoplankton species. Physicochemical properties of water such as temperature, dissolved oxygen, pH, EC and TDS were measured in each sampling in 5 stations. In this study, 42 genera of phytoplankton belonged to 5 phyta (Bacillariophyta, Cyanophyta, Chlorophyta, Euglenophyta and Pyrrophyta) were identified. The average annual density of phytoplankton was 34765± 6261 cell/ml-1. Bacillariophyta with the density of 15465± 765 cell/ml-1 and the abundance of 44. 48% and Pyrrophyta with the density of 550± 478 cell/ml-1 and the abundance of 1. 58%, respectively had the most and the least annual density of phytoplankton which had a significant difference in comparison with other phyla (P<0. 05). Biodiversity indices (Shannon, Simpson and Evennes) showed significant difference between the seasons (P<0. 05) but there was no significant difference between stations. The highest Shannon and Simpson diversity incidence was observed in autumn and its lowest level was observed in summer (2. 8 and 0. 92, 1. 1 and 0. 46). Species diversity has been reduced in summer due to high temperature, decrease of the surface of water and high evaporation. The results showed that there was a negative correlation between the density of phytoplankton and the investigated factors, but there was no significant correlation between them. The highest negative correlation was observed between pH and TDS with the frequency of phytoplankton. The Maron Dam Lake is not rich in phytoplankton density, probably due to the large amount of water to be emitted per year for farming and the presence of several species of fish in water.

In this research, gelatin was extracted from cultivars under different pH conditions (3, 5, 7 and 9) and used for film production. The effect of pH used in gelatin extraction on the properties of films, physical, mechanical, optical and infrared spectroscopy tests, and the measurement of thermal-weighted variations of the films. Based on the results in this study, the highest tensile strength was observed in films with pH of 7 and elastomeric, the highest at pH 5. The solubility and inflationability of the films produced had the lowest pH values at pH 7 and pH5, respectively, indicating a relatively better resistance to water compared to other films. In terms of permeability to water vapor, the most suitable state was observed at pH 7. Optical properties and transparency of films generally did not show significant differences. The results of the infrared spectroscopy also indicated that films produced in neutral conditions of pH 7 compared to higher and lower pHs, due to lower degradation processes, had a trivial spiral content that improved their mechanical properties compared to other films. Generally speaking, film films produced from pH 7 were more suitable for mechanical properties and water resistance than films produced in other pHs. Also, the thermal stability of films produced at pH 7 was higher than pH 5, which can be attributed to the degradation effect of acid extraction pH.

Diversity and abundance of Chironomidae larvae in Sefidroud estuary (south Caspian Sea basin), in order to determine of diversity and distribution pattern and how their relationship with environmental conditions were studied. Sampling of substrate sediments was carried out bimonthly from November 2014 to September 2015, using Van Veen grab (0. 03 m2). Sampling was carried out at three stations (S1 in the river, S2 in estuary and S3 in the marine), with three replicates. Environmental factors in water such as temperature and salinity and sediment relevant factors such as grain size and total organic matter percentage (TOM) were measured. In the present study, 11 genera belong to three subfamilies, including Chironominae (5 genera), Orthocladinae (5 genera) and Tanypodinae (1 genera) were identified. The highest average abundance was related to procladius (300 ± 165 ind. m-2) in river station (S1) in March and the lowest for Paratendipes (11± 6 ind. m-2) in estuary station (S2) in July. Results of temporal distribution showed that the highest and lowest abundance of Chironomidae larvae were in March (149 ± 75 ind. m-2) and in July (25. 6 ± 14. 6 ind. m-2), respectively which showed significant difference (P<0. 05). Spatial distribution of Chironomidae larvae among sampling stations showed significant difference (P<0. 05), as river station (S1) was higher abundance (96. 8 ± 52. 5 ind. m-2) than estuary station (S2) (54. 6 ± 27. 8 ind. m-2) and marine station (S3) (0 ± 0 ind. m-2). At the marine station (S3) no specimen of Chironomidae larvae was found. A significant correlation (P<0. 05) between the abundance of Chironomidae larvae and environmental variables in water and sediment were not observed. Among the studied environmental factors, water salinity and sediment grain size have the most effective on the distribution and abundance of Chironomidae larvae.

Due to subsidiary effects of consuming artificial antioxidants and also a high increase of bacterial resistance to the antibiotic, identification of antioxidant and antimicrobial compounds of natural origin have been considered. Therefore, the present study was performed to evaluate the antioxidant and antibacterial activity of aqueous extract of brown seaweed Nizimuddinia zanardini. Sampling operations were conducted in winter 2014 from the Connie region of Qeshm. The antioxidant activity was evaluated by examination of inhibitory effect of hydroxyl radicals, chelating ability of ferrous ions and total antioxidant activity. Antibacterial activity of extract on four strains of pathogenic bacteria including: Escherchia coli, Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus were evaluated by disc diffusion method and the results were compared with standard antibiotics. The results showed the total antioxidant activity (70. 42± 3. 71mg/kg), hydroxyl radical scavenging ability (81. 66± 7. 63) and the ability of ferrous ions chelating (76. 24± 0. 39) were high in studied seaweed. Staphylococcus aureus, indicated the most sensitive with inhibition zone diameter of 12. 62 ± 0. 74 mm to the aqueous extract of N. zanardini, so that compared to the commercial antibiotic amoxicillin showed a statistically significant difference (P<0. 05). Escherchia coli, showed the highest resistance. According to the results of this study, N. zanardini can be used as a potential source of antioxidant and antibacterial compounds in food and pharmaceutical industries.

Golden grey mullet (Liza auratus) is one of the most valuable bony fishes in southern part of Caspian Sea. Generally, the aim of this study was studying hematological, biochemical and immunological parameters in different ages and sexes in Golden grey mullet (Liza auratus). In order to do this research, 200 fishes with different ages and sexes were collected from the beach of Bandar Anzali in 2015. The average total weight and total length were 270. 10± 82. 60 and 32. 67± 3. 38. Immediately after sampling, the fishes were divided into two sex groups and 5 age groups (3, 4, 5, 6 and 7) and then fish were taken blood. The results showed that there was no significant difference between males and females in terms of all blood, biochemical and immunological factors (P> 0. 05). There was a significant difference between different ages in MCV, neutrophil and lymphocyte levels (P<0. 05) and in other factors there were no significant differences (P> 0. 05). Generally, it can be said that the sexually transmitted fish do not have a significant effect on blood, biochemical and immune factors, while the age of the fish only affects some blood factors that can be affected by the physiological activity of the body and even the environment.

This research aims to investigate the effects of freezing and frozen storage at-18° C on the chemical quality and microbial load of edible tissue of Nemipterus japonicus. 24 samples of fish with average weight and length of 660 ± 23. 3 g and 31 ± 1. 65 cm were obtained from the fish market of Bushehr seaport in autumn 2015 and were stored for 180 days in a freezer. Chemical features (including crude protein, crude fat, ash, moisture, pH, total Volatile Nitrogen and Peroxide) and microbial load (total bacterial count) were determined monthly. Data were analyzed using the SPSS (18th edition) for Windows program. The results of this research indicated that the amounts of crude protein, crude fat, ash and moisture of fresh samples were 15. 80 ± 0. 20, 4. 27 ± 0. 21, 1. 63 ± 0. 54 and 78. 64 ± 0. 77 %, respectively; whereas these amounts were changed to 15. 50 ± 0. 23, 4. 07 ± 0. 06, 2. 79 ± 0. 19 and 77. 32 ± 0. 56 %, respectively after 180 days of frozen storage. The amounts of pH, total volatile nitrogen and peroxide of fresh samples were 6. 90 ± 0. 04, 13. 78 ± 0. 22 mg N2/100g and 0. 91 ± 0. 09 meq O2/kg, respectively; whereas these amounts were changed to 7. 82 ± 0. 15, 17. 17 ± 0. 31 mg N2/100g and 1. 99 ± 0. 11 meq O2/kg, respectively after 180 days of frozen storage. Microbial analysis showed that total bacterial count in fresh sample was 3. 11 ± 0. 13 log CFU/g that was changed to 3. 56 ± 0. 11 log CFU/g after 180 days of frozen storage. According to these results and by comparing the results with the standards, Nemipterus japonicas edible tissue had acceptable quality after 180 days frozen storage.