مجله زیست شناسی ایران
سال بیست و سوم شماره 6 (بهمن و اسفند 1389)

RecQ helicases play crucial roles in DNA related processes such as replication and recombination. They are found in a wide range of organisms including bacteria and human. The RecQsim gene is a member of the RecQ family unique to plants. Here, we report on phenotypic analysis of a recQsim mutant of Arabidopsis thaliana in which the RecQsim gene is knocked out by insertional mutagenesis. Under standard growth conditions, recQsim mutant plants grew relatively faster than the wild type and did not exhibit any obvious developmental defects, suggesting that the RecQsim gene is not essential for plant development. The mutant seedlings, however, were found to be more sensitive to ultraviolet light compared with the wild type plants. The wild type and the recQsim mutant seedlings were not different in response to the genotoxic agent methyl methanesulfonate; however, the mutant plants were more sensitive to the genotoxic agent mitomycin C than the wild type. Thus, the Arabidopsis RecQsim gene might be involved in modulation of plant responses to DNA damage. Further detailed functional analysis of RecQsim may reveal novel pathways in signal transduction of genotoxic stress.

According to the wide range of monoclonal antibodies applications in distinction and treatment of diseases, their production from safe, permanent and inexpensive sources has a great importance. The camel-based single-domain antibody (VHH) has individual characteristics such as: similarity to human VH fragment, solubility, high affinity and specific attachment to the antigen. So it has preferred to the other kinds of antibodies. In this report the antibody gene against MUC1 was transferred into Canola plants by agrobacterium mediated transformation method. The transformed plants initially selected on kanamycin (10-25 mg l-1). The presence and expression of the transgene was confirmed in transformants by PCR and SDS-PAGE. This study is an attempt for transfering an antibody gene to Canola and preparing the best field for production of other recombinant proteins in this plant.

Microorganism activity in the biological reactor converts contaminants to harmless products. Bio-filter is a continuous biological reactor and a new technology for decomposing different contaminants. This study aimed to evaluate of acclimatization Thiobacillus thioparus to removal hydrogen sulfide in a bio-filteration system with used seashell for packing media. For reproduction and microbial activation, it require to prepare special culture medium, vitamin and trace elements solution. After made three solutions we cultivate the bacteria. The bio-filter column were constructed using transparent plexyglass with a height of 40 cm and diameter of 15 cm and bed depth of 27.5 cm, fulled by seashell packing media. The porosity of seashell packing media is 63 percent. Bio-filter has four inlet pipes in above space. This pipes use for injecting air flow, injecting polluted gas, effluent readings for H2S, injecting nutrient and culture medium. Bacterial activity have been surveyed for 15 week and removal efficiency by T. thioparus were evaluated and various concentrations, less than 20 mg/m3 to more than 100 mg/m3. The best performance observed in 29oC. Also optimum pH was 7-7.5 for a stable system. The number of measured samples were 550 and for each concentration at least 6 reading at different time. The results observed that, the removal efficiency was increasing so the adaptation process was increasing. It was possible that increase of concentration inlet polluted gas without affect on the removal efficiency. It means that the bio-filter is stable. The obtained results observed that polluted gas concentration has not significant effects on gas treatment process and removal efficiency were 78-88 percent, when the T. thioparus acclimated in the desirable conditions for removal polluted gas. Also removal efficiency will remain well when the humidity rate was 77-93 percent and temperature was 20.5-30oC in growth and reproduction of T. thioparus. When T. thioparus acclimated and obtained stable conditions in seventh week, biomass production rate would be increasing and upward until fifthly week.

Screening for bacteriocin production by strains of lactic acid bacteria (LAB) from local dairy products in Iran resulted in detection of nine strains bacteriocin producing strains. Among 105 isolates, nine bacteriocin producer were phenotypically and biochemically identified as Lactic acid cocci. The anti-microbial compounds produced by these novel strains were inactivated by trypsin, proteinase k. These bacteriocins also were active in wide range of pH and wide range of temperature. bacteriocins produced inhibited not only the closely retaliated LABs, but also Listeria monocytogenes.

Heterocystous blue-green algae (BGA) are group of nitrogen fixation free living microorganisms that grow naturally in paddy fields. In this research BGA population of one paddy in Gillan province in different seasons, were isolated, identified and added to rice and soaked seeds as a biofertilizer. In this examination pH and moisture of soil were measured. In another examination, 2g algae were added to rice pots and plant height and total weight, root length, moisture, bulk density, particle density and porosity of soil were surveyed. Anabaena was the only heterocystous BGA found in soil samples with four species: A. spiroides, A. osillarioides, A. torulosa and A. variabilis. The highest and lowest pH (6.7, Springer & 6.2, winter) and moisture of soil (43%, Springer & 36%, winter) was in spring and winter, respectively. In addition the highest of blue-green algae population in spring (20, 12 in A & B medium) and lowest in winter (5, 4 in A & B medium) were observed. Rice seeds soaked in water and BGA germinated earlier than control seeds and the height of seedlings and roots of treated seeds were more than seeds soaked in water after 20 days. The result of pot culture experiment were: 53% increase in plant height, %66 increase in Roots length, %58 increase in Weight of fresh leaf and stem, %80 increase in Weight of fresh root, %125 increase in Weight of dry leaf and stem, %150 increase in Weight of dry root of seedling grown in pots and %20 increase in Moisture and %9.8 decrease in Bulk density, %4.8 decrease in Particle density, %28 increase in Porosity of soil and there were significant differences in pot treated with BGA as compared with control.

Ornithobacterium rhinotracheale is a gram negative, highly pleomorphic, rod-shaped bacterium that is caused economical losses in respiratory complexes in poultry industry. The present study was conducted to determine ORT antibiotic sensitivity from broiler breeders in Guilan province for introduction of the best antibiotic to treatment. In this study, tracheal swabs of 22 broiler breeder flocks were collected and ORT was isolated in 5 flocks (%22.73). Drug sensitivity test using standard disk diffusion technique was performed with 27 antibiotics. All isolates were susceptible (%100) to: Ceftriaxon, Ceftizoxim, Ciprofloxacin, Enrofloxacin, Difloxacin, Flumequin, Tylosin, Tiamulin, Tetracyclin,Chloramphenicol, Nitrofurantoin and furaltadon. Also %100 of the isolates were resistant to: Cephalexin, Erythromycin, Gentamycin, Neomycin, Penicillin, Ampicillin, Colistin and Sulfametoxazol-trimetoprim.Eighty percent of the isolates were susceptible to Doxycyclin and %40 to furazolidon, %80 were resistant to licomycin and %60 showed moderate sensitivity to lincomycin.

Feeding regime of 55 Persian sturgeon caught from southern basins of the Caspian Sea was studied in 3 length classes of <30, 30-60 cm and >60cm. Fish were sampled using bottom trawl at 85 sampling sites at depths varying from 2 to 100m. Food organisms identified in gut contents belonged to families of Gobiidae, Mysidae, Gammaridae, Nereidae, Ampharetidae, Psudocumidae, Clupaidae, Syngnathidae, Scorbicularidae, Cardidae and insects. Our study revealed that feed diversity decreases with increase in length e.g. 8 food items were observed at length class 1 while fish at length group of II and III fed on 5 and 2 items respectively. Mysidae, Gobiidae and Nereidae were the dominant food at length class below 30 cm and for those fish categorized at 30- 60 cm length class the dominant food was Gobiidae and Mysidae. Family Gobiidae was the dominant food for fish in length class over 60 cm. Mean values of gut vacuity index (CV) for length class 1 was 28 which refers to a good feeding condition. This index in length class 2 and 3 were 4.54 and 50 respectively refering to an intermediary feeding condition.

Since specific environmental conditions in estuarine of Gorganrude river is present and biological characteristics and population parameters are influenced with these environmental conditions, we examined biological characteristics of Crucian carp in Gorganrood estuarine and compared with the other environment. Sampling was done in autumn and in Gorganroud estuarine. Total 49 studied samples belonged to three age groups, 1+, 2+, 3+. Average total length of each groups were 75.48, 122.81, 151 mm and average weight were 8.48, 29.61, 62.2 grams, respectively. In whole specimens just females were detected and it probably related to parthenogenesis of given species. Fulton Factor equals 3.18 and it revealed positive allometric growth. Moment growth coefficient between age group 1+ and 2+, between age group 2+ and 3+ were 0.57 and 0.32, respectively. It could be due to the increased gonadic growth and reduced in somatic growth among higher ages. Relative intestine length was approximately 2.57 and it reflects the feeding strategy of crucian carp which is herbivores. Coefficient factor was calculated for expressing nutritional status and it equaled 1.06, which is due to the time of sampling (autumn) and unfavorable environmental conditions. Regression coefficient of length and weight was 0.99 and it reflects high relation between length and weight in this species.

Considering nutritional value of Artemia nauplius, it`s widely used feeding shrimp post larvae, early life stages of sturgeon larvae, ornamental fish and marine fish larval.In order to comparison some important characteristics of Artemia cysts, were collected from three different location across Iran including Urmia lake, Maharloo lake and Meighan of Arak. Different biometric characteristics were measured and analyses. Cysts were hatched under identical standard conditions and measured as the length of InstarI nauplius. To determine the cyst diameter and chorion thickness, cysts were cultured in D & K after nocturnal incubation, decapsulated. Then decapsulated and non-decapsulated cyst diameters measured by binocular loup equipped with micrometer eye lenses.Data were statistically analyzed by SPSS software and tested by ANOVA, Duncan test. results of these comparisons on means of chorion layer thickness, cysts diameter ranges in 3 geographical habitats of Iran to introduce to larvae-culturists showed that The largest nauplii were obtained as Instar I, belongs to Artemia from Urmia lake and the smallest one belongs to Artemia from Meighan desert of Arrack at sizes of 511.8, 504.9 micrometer respectively. Also the largest to smallest means of cysts diameters were due to Urmia lake Maharloo Lake and Meighan desert area of Arrack. (285.4, 281.3 and 280.1 respectively).although the chorion thickness of Urmia lake Artemia was smaller than other strains.

A 24-day feeding trial was conducted to determination of optimum time for rainbow trout (Oncorhynchus mykiss) larvae fed on Artemia nauplii and formulated diet in Ghezelparvar center, Arak. Rainbow trout larvae with mean body weight of 0/1±0/002 g were divided into 3 treatments (with triplicate) and fed on trout starter feed (group A), A. nauplii (group B), combination of A. nauplii + formulated diet (group C) at the first series of the experimental period for 10 days. At the second series of the experiment (11th-24th day), fish in group B divided in group B1 (fed formulated diet) and group B2 (fed formulated diet + A. nauplii). Also, fish in group C divided in group C1 (fed formulated diet) and group C2 (fed formulated diet + A. nauplii). Fish in group A fed with formulated diet at total period of the study. After 24 days feeding trial, growth factors and survival were compared. Results showed that the fish fed with diet B2 exhibited statistically significant differences in final weight, FCR, SGR and weight gain percent (P< 0/05). Coefficient of variation for body weight in the fish fed with diet B2 was significantly better than the other treatments. There was no comparable difference between group C1 and C2 and also B1 and A in some growth factors (P> 0/05). Survival in group B2 was higher than the other treatments (P<0/05) and the lowest survival was observed in group A. These results indicated that the use of A. nauplii from the larval active swimming onset time to all larvae swimming time and then use of combined diet (formulated diet + A. nauplii) can improve growth performance and survival of rainbow trout (Oncorhynchus mykiss) larvae.

This study was carried out to determine thyroid gland activity during salinity changes in Caspian trout (Salmo trutta caspius Kessler, 1877) juveniles. Specimens were exposed in 4 weight groups of 5, 10, 15 and 20 g, in 3 salinity trials: Caspian water (11- 11.5 ppt), inshore water (7 ppt) and fresh water (control). Each trial was done in 3 replicates. Plasma osmolarity was measured by osmometer. The tissue fixations carried out from juveniles of control group (in fresh water) and different hours after exposure of fish in salinities. Histological indicators including thyroid gland morphometric parameters were assessed using classic preparation and optic microscope with digital camera. Histology of thyroid gland of juveniles acclimated to 7 ppt salinity and Caspian water showed that after the transfer of 10, 15 and 20 g weight groups to saline water, the gland became more active at early hours and gradually returned to initial condition after 10 days. The same activity was not observed for 5 g juveniles. Based on the results of osmoregulation variation, it can be confirmed that weight groups 10, 15 and 20 gr can do hypoosmoregulation of the salinity of the Caspian Sea, but the weight group of 5 gr do not have such a ability.

In this research, effects of striping frequency on eyed eggs rate and sperm parameters quality in 3+ year’s age of male Oncorhynchus mykiss were investigated. Broodstock males were allocated randomly in three groups for stripping interval at weekly, 10 day or biweekly. Results show that duration of sperm motility in weekly striped males was the highest about 26.5±1.2 second. Also sperm density rate in weekly striped males had lowest amount about 38±0.9 %. Besides eyed-egg stage rate in weekly striped males had lower rate about 80.6±1.1 % which had significant difference compare to others group. Final conclusion revealed that in frequent stripping from 3 years male broodstock, weekly stripping were resulted to lower sperm quality. But when this period excess to biweekly interval, the brooder will have enough time to reproduce higher quality sperm through spermatogenesis approach.

Hormoz Island has suitable coasts for hawksbill turtles nesting from south to northeast. Started nesting season from March 2005 and continue to June 2006. Totally 20 nests selected and conservated for number parameter measurement, for example: nest depth, distance nest from sea, percent hatching success, incubation period, total eggs. The result show: the mean of depth nest 50 cm, mean distance nest 12m, average total egg 91, average incubation period 67 days, average hatchlings weight 15.1 gr and mean of hatching success 73%. Total eggs with egg diameter have a significant negative correlation (r= - 0.60) and with nest depth significant positive correlation(r= 0.32), also recorded significant positive correlation between straight carapace length with weight(r=0.88). Compare between total eggs of this area and south of the Persian Gulf with other world area showed that these area (Hormoz and south Persian Gulf) have a low total eggs.

This experiment was conducted in eight generations for investigation on effects of selection by index on economic- genetic trend in three economical traits in silkworm commercial lines currently is used at Iran. Genetic and economic improvement was estimated by heredity value average difference of individuals in two successive generations. Meanwhile economic efficiency for production system estimated by genetic improvement multiple economic values for each trait. From obtained results, the Xinhang1 line had the highest total economic- genetic improvement and Y line had the lowest total economic- genetic improvement. Curve of economic- genetic value was as sigmoid shape and its slope increased during third generation according to increase of selection accuracy. Shape of economic- genetic improvement was sinusoid plot. Curve peak in Xinhang1 and Koming1 were observed at fourth generation. From obtained results, it was showed selection index could improve lines performance. Therefore selection index must replace current method. The results of this research showed that the impact of use of selection of silkworm cocoon based on selection index, could lead to improvement in quality and quantity of cocoon, economic efficiency of production system and sericulture industry in Iran.

The thyroid gland is one of the important endocrine glands of the body that plays vital roles in the regulation of metabolism and growth. Thyroid dysfunctions are considered as one of the most important endocrinopathies. Trace elements as Zinc (Zn) and Copper (Cu) play an important role in the properly performance of the most body functions. Thus a small change of these elements causes main disruptions in the structure and function of body. The aim of the present study is hypothyroid induction and investigation of its effect on serum level of trace two elements, Zn and Cu. Twenty-one male rats weighting 135-145g, divided into three groups. The control group received drinking water; hypothyroidism groups received two doses of propylthiouracil (PTU), low dose treatment group, received 1mg/100ml in drinking water and high dose treatment group, received 10mg/100ml in drinking water, for 60 days. At the end of experiment the animals were sacrificed, serum samples were obtained and thyroid gland was removed. Serum hormones level of T3 and T4 was determined with radioimmunoassay and serum levels of Zn and Cu was determined with graphite atomic absorption spectrophotometer. Results showed that the serum level of T4 was reduced significantly in treatment groups compared to control. The serum levels of Zn compared to the control group reduced but the serum levels of Cu increased. Thus, PTU by induction of hypothyroidism and changing in the level of T3 and T4 causes changes in homeostasis of Zn and Cu elements in body.