فصلنامه فیزیولوژی و بیوتکنولوژی آبزیان
سال یازدهم شماره 2 (تابستان 1402)

In this study, the effect of two plant extracts, garlic and thyme, on the theront and tomont stages of the parasitic protozoa Ichthyophthirius multifiliis was evaluated. For this purpose, first, hydroalcoholic extracts of these plants were prepared. In the next step, both stages of the parasite were exposed. The parasite survival rate at each concentration, every 3 hours and for 12 hours were recorded and LD50 of each extract in this time period was calculated using Probite method. Malachite green was used as a positive control. The results showed that the LD50 of garlic and thyme on tomont were 1 and 2.5 mg/L, respectively. While this amount was 0.24 mg/L for malachite green. LD50 of garlic and thyme extracts on theront were 1.66 and 0.57 mg/L, respectively, and in the case of malachite green was 0.121 mg/L. According to the results, the antiparasitic effect of garlic and thyme extracts is insignificant compared to the effects of malachite green and it is not possible to replace malachite green with these extracts. Although these extracts can be used as adjunctive therapy along with chemical treatments.

This study was conducted to determine the effective factors on Baetis larva haplotype diversity in upward of Gamasiab River. The macrobenthos sampling was done from four stations ranged source of the river downward, about 500 meters from each other, in four seasons, with three replications from the middle and riversides by the Surber sampler. After identification, isolation and fixation of the Baetis, they prepared for molecular experiments. After DNA extraction, gene amplification and sequencing, haplotype diversity of Baetis larva for each season in different station was performed with MEGA 6.06 software. Molecular investigations indicated that the reduction of haplotype diversity at station 2 exposed to wastewater effluents of trout farm. Sequencing parameters in other stations were not significant. Therefore, the effect of effluent in haplotype diversity was not remarkable.

Cancer is one of the leading causes of death worldwide. Chemotherapy drugs have many toxicities and side effects. Therefore, designing effective natural medicines with the least toxicity is very important. Aquatic organisms are a rich source of bioactive compounds including peptides with anti-cancer properties. In studies, it was shown that an 11-amino acid peptide derived from the hydrolysates of dark muscle by-products of tuna (Thunnus tonggol) has anticancer properties. In the present study, the effect of this peptide on the viability of 4T1 breast cancer cell line was evaluated using MTT assay and induction of apoptosis in these cells was assessed using flowcytometry and Real-time PCR. The results showed that this peptide inhibited cancer cell viability and induced 30.3% of apoptosis in these cells. The peptide acts through reducing the relative expression of the anti-apoptotic BCL2 gene and increasing the relative expression of the pro-apoptotic BAX gene. Therefore, it can be suggested that this peptide has the potential to be more investigated for therapeutic purposes as well as for supplements with cancer prevention properties.

In this study, the effect of gibberellic acid on vegetative and heterocyst cell size, inducing sugar and protein content was investigated in Anabaena at three durations (7, 14 and 21 days). According to the results, vegetative cell size did not show any significant differentiation under gibberellic acid treatments and time duration. Length and width of heterocyst cells showed a significantly different impact only with 10µM gibberellic acid at 7-day-old cultures. Algae treated with gibberellic acid had more fresh weight. Gibberellic acid induced heterocyst formation after 14 and 21 days. The amount of photosynthetic pigments increased in the 7 and 14-day cultures and decreased in the 21-day cultures. Application of gibberellic acid to the culture medium did not affect heterocyst percentage after 7 days, but it increased the heterocyst numbers in the 14 and 21-day cultures. Reducing sugar content changed dependence of gibberellic acid concentration and growth period. Treatment with gibberellic acid could increase protein content at different concentration and growth period. The results of this research showed notable effect of this plant growth regulator on Anabaena.

The present study was conducted with the aim of comparing the morphological and reproductive indices of spring and autumn migratory Mahi sefid populations to Anzali lagoon. Therefore, 120 spring and autumn migratory Mahi sefid were caught at a station leading to Anzali lagoon. The results of the comparison of morphological characteristics showed that these characteristics were significantly higher in autumn broodstocks than spring broodstocks. Based on the analyzing into main factors, total length, fork length, standard length and body weight traits expressed 73.33% of the diversity of morphological characteristics between spring and autumn populations. Comparison of reproductive characteristics did not show any significant difference in absolute fecundity between spring and autumn populations (P>0.05). The average relative fecundity, number of eggs and sperm volume of the spring broodstocks were significantly higher than the autumn breed (P<0.05). The fertilization percentage after 24 and 48 hours in the autumn form were significantly higher than the spring form (P<0.05). Therefore, the broodstocks of the autumn form were higher in morphological characteristics and fertilization percentage, and the broodstocks of the spring form were higher in relative fecundity, number of eggs and sperm volume.

Different physicochemical factors influence the growth of Haematococcus pluvialis and should be assessed in order to optimal production of biomass and its chemical composition. There is few information on the effect of gradual nitrogen limitation on the microalgae.  Hence, in the present study the effects of gradual nitrogen removal from culture medium, in two stages, on growth, chlorophyll and astaxanthin content, biochemical compounds and fatty acid profile in H. pluvialis was evaluated. During 55 days culture, biomass production and chlorophyll content in the treatment group showed a significant decrease (P<0.05) compared to the control, whilst no significant change was observed in the astaxanthin content. The highest content of astaxanthin was observed before the replacement of culture medium in both experimental groups. At the end of the experiment, the content of lipid, protein, and carbohydrate in the nitrogen-free culture showed a significant decrease. Fatty acid profile showed a reduction in unsaturated fatty acid with nitrogen limitation. Overall, the results showed that the stepwise nitrogen depletion caused a change in biochemical composition of microalgae. In the same condition, as the algal cells were gradually subjected to severe stress, consequently, the production of astaxanthin was not affected.

The use of nanotechnology products in cancer diagnosis and treatment has gained attention. The current study was performed to synthesize BiFe2O4@Ag nanocomposite using the extract of alga Scenedesmus obliquus and to evaluate its effect on the viability and apoptotic genes expression of gastric cancer cells (AGS). MTT was performed to determine the effect of the nanocomposite on cell viability of cancer cell line (AGS) and normal cell line (HEK293) and calculation of 50% inhibitory concentration (IC50). Also, Real Time PCR was used to determine the relative expression of CASP8, CAD, and p53 genes. According to the results, at 31.25µg/mL and higher, BiFe2O4@Ag was considerably cytotoxic for AGS cells. 50% inhibitory concentration was 56µg/mL for cancer line and 134µg/mL for normal line. Also, exposure of cancer cells to BiFe2O4@Ag significantly increased the expression of the CAD, CASP8 and p53 by 3.5, 3.27, and 2.51 folds, respectively. According to the results of this study, BiFe2O4@Ag nanocomposite has proper anticancer potential against gastric cancer cells and activation of apoptotic signaling pathways is proposed as a mechanism of cell inhibition.