مجله پژوهشهای جانوری (زیست شناسی ایران)
سال سی و ششم شماره 1 (بهار 1402)

The Caspian kutum is one of the most important economic and native species of the Caspian Sea. Kisspeptin neurons act as a central processor in the transmission of peripheral signals to gonadotropin receptor (GnRH) neurons. To investigate the role of kisspeptin, especially Kiss1 in the reproduction of the Caspian kutum, the expression of the Kiss1 gene in brain tissue was evaluated using real-time PCR. For this purpose, 36 pieces of fish were caught from Anzali shores from November 1997 to May 1998 with an average weight of 650±50 g and a length 35.5±0.2 cm and brain tissue was separated. After extraction of total RNA and cDNA synthesis from brain tissue, expression of the Kiss1 gene was performed using real-time PCR technique by reference gene-actin-β. Data were evaluated using one-way analysis of variance (ANOVA) and Tukey post-test and 95% confidence level and the significant difference in expression of the Kiss1 gene was calculated per month in both sexes. The results showed that the expression level of the Kiss1 gene in the brain tissue of male and female fish showed a significant difference in different months (p< 0.05). The highest expression of the Kiss1 gene in both sexes was reported in May during the Caspian kutum spawning. In addition, morphohistology of gonads showed that the highest sexual maturity was from March to May. In conclusion, it seems that it can be stated that Kiss1 has the highest level of expression in the months when the Caspian kutum reaches its sexual maturity.

High ambient temperature (HT) and heat stress has negative impact on physiological functions. L-tryptophan, serotonergic and kynurenine pathways, has calmative effect during different stress status. This Study was designed to investigate intraperitoneal administration of L-tryptophan (50 mg/kg body weight) during either HT (39 °C) or normal temperature (NT; 31 °C) for 5 hours on cumulative food intake at 1, 2, 3 and 4 hours and diencephalic NPY and CRF gene expression with qPCR method at 5 hours after tryptophan administration. In both two heat stress groups, NPY gene expression significantly was increased in compare with normal temperature groups. Cumulative food intake was increased in heat stress group by tryptophan injection. These results showed that NPY increased to compensate reduced food intake, as anti-stress factor, in heat stress condition and tryptophan maybe involve to improve this effect. Heat stress significantly increased CRH gene expression but tryptophan administration significantly reduced it during heat stress. These results showed, tryptophan modulated Hypothalamus-Hypophysis-Adernal axis by changing in CRH gene expression and tryptophan has buffering effect on stressful states.

Antioxidant enzymes are an important part of the body's immune system that are highly reactive to contaminants. In this study, changes in the levels of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) in chiton (Acanthopleura vaillantii) were investigated in response to heavy metal contamination of copper, zinc and chromium on the coast of the Oman Sea. For this purpose, 18 sediment and 180 chiton samples were collected from Ramin, Daryabzorg, Maritime University coast, Tis, Konarak and desalination stations. After samples biometry and separating the soft tissue, the amount of antioxidant enzymes was measured by enzyme assay kits. The bioaccumulation of heavy metals in the soft tissue of chitons and sediments after acid digestion was read using an atomic absorption spectrometer. Concentration of heavy metals (µg/g dry weight) in soft tissue of chiton were recorded copper (18.44 ± 0.07), zinc (37± 0.12) and chromium (6.8±0.13), respectively; and in sediment copper (7.3±0.1), zinc (17.3±0.28) and chromium (23.5±0.18). The levels of catalase and superoxide dismutase were 20.75±4.85 and 16.27±6.05 nmol/mg protein in chiton soft tissue, respectively. The pattern of accumulation of heavy metals in the soft tissue of chitons was recorded as chromium Ramin> Konarak> Daryabozorg> Tis> Desalination.Examination of sediment contamination with sediment quality standards showed that sediments were safe in terms of metals studied on the coasts of the Oman Sea.

Body size is a fundamental characteristic of organisms and is expected to decrease in response to environmental stresses such as heat stress, and its estimation is an important step in addressing many ecological questions in aquatic environments. The aim of this study was to investigate the effect of environmental factors on body size and diversity of macrobenthos communities in Gomishan wetland and Miankaleh Bay. For this purpose, macrobenthos was carried out by leaf packages in summer 2017. The results showed that the average temperature, salinity and electrical conductivity in Gomishan lagoon were higher than Miankale Bay, but no difference was observed in terms of dissolved oxygen and pH. The average dry weight and total length of the Zygoptera showed no significant difference, Shannon's species diversity and evenness indices showed a significant difference in two ecosystems. The results of covariance analysis between dissolved oxygen, salinity, body weight and abundance on leaf pack decomposition showed that only water salinity has an inverse relationship with the decomposition rate. The results of factorial rotation matrix showed that temperature, longitude and latitude and k-day had a positive effect and pH, salinity and oxygen had a negative effect on the abundance of macrobenthos. The results showed that the changes in environmental parameters such as temperature had an effect on the metabolism and weight of the biomass of different species, so that the average weight of many different species in the warmer water of Gomishan Lagoon was lower than that of Miankaleh Bay.

Scopolamine impairs memory by causing oxidative stress in brain cells, especially the cortex and hippocampus. Medicinal plants with various effective compounds can have antioxidant effects. The aim of this study is to investigate the effect of the methanolic extract of Zirfon plant on oxidative stress and working memory impairment induced by scopolamine in male Wistar rats. In this experimental study, thirty-six male Wistar rats were randomly divided into six groups of 6. The control group, Scopolamine group (1 mg/kg), Extract Group (300 mg/kg), and Extract groups 100, 225, and 300 mg/kg together with scopolamine which received extracts as gavage and scopolamine intraperitoneally for 10 days. After performing the behavioral test of the New Object Identification Test (NORT), hippocampal and cortex tissues were sampled to measure the activity of catalase (CAT), superoxide dismutase (SOD), and acetylcholinesterase (AChE). Our results showed that injection of scopolamine reduces the discrimination index in NORT. The dose of 300 extracts had the highest effect, so even in its administration together with scopolamine, a significant (p<0.001) reduction in the number of working memory errors was created. Biochemical findings in hippocampus and Cortex Tissues showed that scopolamine decreased the activity of antioxidant enzymes (CAT and SOD) and increased the activity of AChE. Treatment with Zirofen extract restored the activity of SOD, CAT, and AChE. The results of this research indicate that Zirfon extract has a strengthening effect on working memory and generally exerts its effect through antioxidant activity.

Rivers are vital ecosystems and their protection is of outmost importance. In this study effects of physicochemical parameters of water on the population structure of Ephemeroptera in three sampling locations e.g. upstream, middle and downstream of the Tajan River were examined. Sampling was carried out on monthly bases from April to March 2019. One-way analysis of variance was used to evaluate the qualitative status of the sampling stations, Principal component analysis was utilized to determine the effect of environmental factors on separation or overlap of the studied stations and comparative conventional analysis was used to determine the relationship between environmental variables with presence and absence of Ephemeroptera families. Results showed that physicochemical factors varied significantly during the study period. The average of factors such as the flow rate (68.3 m3/sec), dissolved oxygen (9.53 mg/lit) and pH (8.31) were at highest levels in February and March while average of EC (1181µm/cm) and TDS (815 mg/lit) were at their lowest values in in September. Significant differences were observed in physicochemical factors at different stations. The differences were apparent between Mohammadabad station with other two sampling stations in terms of temperature and dissolved oxygen and Tajan station varied significantly with others in terms of EC, TDS and Debi. Significant relationship was observed between frequency and presence of some families of Ephemeroptera including Baetidae with EC and TDS and Oligoneuridae with pH and dissolved oxygen which allows considering these groups as qualitative indicator or indicator species of surface water resources.