فصلنامه بوم شناسی آبزیان
سال دوم شماره 3 (پیاپی 203، زمستان 1391)

In quantitative real-time PCR¡ the mRNA level can be quantified in relative terms based on the expression ratio of mRNAs of the target gene and an internal reference gene. Since¡ an internal standard should be expressed at a constant level among different tissues of an organism at all stages of development¡ and should be unaffected by the experimental treatment¡ the stability of different reference genes needs to be tested for every new experiment to select the most suitable reference gene for normalization of target gene. Here in this study¡ the stability of six candidate reference genes including ribosomal protein L6 (RPL6)¡ ribosomal protein L13 (RPL13)¡ Elongation factor 1-alpha (EF1A)¡ Ubiquitin (UBQ)¡ Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-actin (ACTB) were studied during early development of Persian sturgeon¡ Acipenser persicus using Real-Time PCR TaqMan. The general consensus from BestKeeper¡ NormFinder and geNorm models indicate that RPL6 and ACTB were found to be the most stable reference genes across the different developmental time-points¡ whereas RPL13 was the most variable gene. Using RPL6¡ ACTB and a two-gene normalization factor based on the geometric average of RPL6/ACTB could be recommended for standardization of qPCR data in future developmental studies of Persian sturgeon and likely in other Acipenserid species.

This study investigates the mucous cells position in fish epidermis and specifically in the part of epidermis that covers fish scales as well as their changes during the time after the fish death it, also, discusses their behavior toward external (outsider) factors such as heat and mineral/organic antioxidants (Sodium Bisulfide and Hydrokinon). The question this study tried to answer was whether or not it was possible to use such cells as the indicator and index of the fish death time and perhaps, the physical and chemical conditions in which the fish has died. The Cyprinus Carpio was used as the subject of this study. Different methods with different indicators in cytochemistry such as PAS, Fuschin Aldehyde, Karmin and blue methylin were used. Among the indicators, the most fruitful result was shown by Fuschin Aldehyde with Bouin Fixator. The findings of the study indicated that the method of investigating mucous cells in fish epidermis could be used as an indicator to determine the fish death time in such a way that an increase in the temperature and decrease in the oxygen of unmoving water would accelerate the speed of such cells death. The last cells were found dead after about 130 hours in epidermis and in fresh water stream with a temperature between 17 and 18 degree centigrade. In 25 degree centigrade, the death speed doubled. Not only did the antioxidant injection have any effect on increasing the cells resisting power, but it decreased it severely to the effect that there were no mucous cells after 90 hours. Such effect can emanate from severe changes in the PH of the body liquid and interference in biological reactions of the fish body.

Chitin and chitosan are the most abundant natural amino polysaccharide that are non-toxic, biodegradable and biocompatible. They have become of great interest not only as an underutilized resource, but also as a new functional material of high potential in various fields. They are biopolymers having immense structural possibilities for chemical and mechanical modifications to generate novel properties, functions and applications especially in various industrial and biomedical fields. In the last decade, chitin and chitosan derivatives have garnered significant interest in the biomedical and biopharmaceutical research fields with applications as biomaterials for tissue engineering and wound healing and as excipients for drug delivery.This review will focus on the structure, properties and applications of chitin and chitosan with particular emphasis on their uses as materials for industrial and biomedical applications.

Study was conducted to determine some biological characteristics and population dynamic of Platycephalus indicus were studied during one year from May 2011 to March 2012 in the coastal waters of Bandar Abbas. A total of 1106 samples were collected. Also, each month 35 fish was chosen and transferred to the laboratory for evaluation of spawning season. The ages of 279 specimens were determined by sectioned otoliths. The ages of the females were estimated to be between 1 to more than 7,while the ages of the males were from 1 to more than 4.The relationship between weight and length (Total length) can be expressed as W=0.004L3.16 35 for male and W = 0.0042L3.1293 for female. This equation indicates that keeled mullet has allometric growth. The values for natural mortality (M) resultant coefficient were M = 0.886 year-1 for females and 0.736 year-1 for males, and the estimated Z values were 1.43 year-1 for females and 1.62 year-1 for males. These ages were then ®tted to the von Bertalanffy growth equations. Equations obtained were Lt = 43.4 (1-exp(-0.45 (t .32))) for males, and Lt = 63 (1-exp(-0.50(t 0.30))) for females.

The toxicity of heavy metals in sediments of the Nayband Bay and Asaluyeh region and potential ecological risk to sediment organisms assessed. Three stations with different degrees of vulnerability of South Pars Oil and Gas Activities (1: Control - 2: medium affected and 3: severely affected) were selected in the study area. Sediment sampling at each station in both cold and hot seasons (2010) were done by Van veen grab. Heavy metal concentration in sediment samples were investigated after the process of digestion and measured by atomic absorbtion. In order to assess the Sediment quality and ecological risk assessment of potential contamination, Contamination Factor (Cf) and Contamination Degree (Cd) were used for heavy metals and sediment, respectively. Finally the risk index was calculated. The highest levels of mercury in stations 3 and Ni, Pb and Zn were measured at Station 1. The maximum amounts of cadmium and copper were observed at station 2. The Most mercury contamination factor value and the least for nickel were obtained at Station 3.The degree of contamination for different stations from the total metal pollution factor was calculated. The maximum contamination level for Station 3 with the amount of 4.51 was obtained. Results showed that, mercury concentrations in the Nayband Bay and Asaluyeh region is upper-middle. Potential ecological risk (Eri), in the case of all metals except mercury, were in low ecological risk. Potential ecological risk of mercury was in very high ecological risk. The three stations were in the most severe ecological risks.