مجله زیست شناسی ایران
سال هجدهم شماره 3 (پاییز 1384)

Parasite infection of 165 specimens of Tench (Tinca tinca) surveyed in Amirkelayeh wetland in the years of 2001 – 2002. According to the results, 8 species of parasites recognized, including: Raphidascaris acus (prevalence = 5.71%, mean intensity = 2.5); Camallanus lacustris (P = 1.9, mi = 1); Asymphelodora tincae (p = 18.09 %, mi = 16.37), Diplostomum spathaceum (P = 4.76 %, mi = 1.2); Dactylogyrus sp. (P = 0.95 %, mi = 20); Caryophyllaeus fimbericeps (P = 0.95 %, mi = 35); Learnaea sp (P = 25.7 %, mi= 8.63) and Trcodina sp. (P = 0.95 %, mi = 4). There species of Camallanus lacustris, Caryophyllaeus fimbericeps and lernaea sp. are reported in Tench for the first time from Iran.

Oxygen metabolites as reactive oxygen species (ROS) are considered as major factors in male infertility. In the present investigation, we aimed to study the effect of different concentrations of ascorbate/vitamin C (300-2000 micromolar), on membrane integrity, acrosome reaction, and viability of bull (Holstein) spermatozoa in presence of iron (ferrous) ions as lipid peroxidation (LPO) promoter. LPO is one of the manifestations of ROS attack in biological membranes. LPO impinges on membrane integrity, triggers inactivation of membrane bound enzymes which involve in sperm motility. Ascorbate in concentrations below 1000 micromolar protects spermatozoa from free radical damages as evidenced from improvement in their membrane integrity (data of LPO test), elevated acrosome reactions, and increased viability. Concomitantly, there is also witnessed depletion of malondialdehyde (MDA)(an end product of LPO) generationfollowing ascorbate supplementation. Ascorbate at 1000 micromolar concentration and above, however, is not protective, as evidenced by abrupt fall in sperm membrane integrity and rate of acrosome reactions and lowered % live sperm cells. Collectively, ascorbate acts as a double-edged sward in different concentrations and researchers must keep in mind this negative side of ascorbate application in their research fields like in vitro fertilization, cell culture, and preservation of gametes to minimize its deleterious impacts on biological systems.

There are many evidences about the effects of soybean on the reduction of cholesterol in blood. In this research we have studied the effects of purified commercial soybean protein-powder (10%, 20%, 30%) on the alteration of blood parameters (total cholesterol, triglycerids, HDL, LDL and VLDL) in hypercholesterolemic male rats. After two weeks of caging and adaptation the rats in appropriate of condition, they were fed for 8 weeks with a basic food plus 2% cholesterol and 0.5% cholic acid to induce hypercholesterolemic state in rats. Then blood samples were taken to measure hypercholesterolemia and other serum parameters. The rats were put 8 more weeks under nutritional regimen including basic food plus commercial protein (10%, 20% and 30%). At the end of test-period blood sample were taken again to measure the same parameters. Statistical analysis methods showed that in the first phase of experiment feeding by the basic food plus 2% cholesterol and 0.5% cholic acid caused significant rise of total cholesterol and LDL, indicating hypercholesterolemic. The feeding of rats by soya protein caused reduction of total cholesterol, triglycerid, HDL, LDL and VLDL. This reduction in discussed due to the presence of some amino acids and also to isoflavones.

Kani Mikaeil cave with an area of about 712 m2 is located in the northeast of Sanandaj in the Zagros region. An archaeological excavation by Palaeolithic Research Center (Roustaei et al 2002) was held in 2001 in this cave to document the prehistoric settlement of man in the region. Several test pits were dug in different parts of the cave. A great number of microvertebrate remains (Rodents, Aves, Amphibien, Reptiles) were found after the systematic dry sieving of the sediments from each section which were found to be originally pellet accumulations. The cave might have been occupied during the last 20,000 years from the late Pleistocene to mid-Holocene. In order to document the environmental changes during this time period the rodent remain from these sections are studied currently at the rodent department of the Science Faculty of the Mashad University. The rest of the material is studied at the Natural History Museum of Paris. The rodent assemblage, the most abundant part, is composed of Hamsters, Jirds, Dipodidae, Wood mouse, Voles, and Pikas. This research presents, the hamsters, for which two genera Mesocricetus and Cricetulus were identified on the basis of tooth morphology and morphometrics.

Amphipods are the main food for many fishes and have high sensitivity to environmental pollution, therefore they are of economical and ecological importance. Due to the fact that the different species of Amphipoda have different physiological and ecological characterestics, the first step in cultureing them is their identification. In this study, the primary objective was to collect and indentify the Gammarus species in Zayandeh-rood River. Eight sites from various sections of the river from the origin to Dorcheh were selected. Sampling was performed seasonally from March 2002 to December 2002. Three samples were taken from each site, using the sampler (dredge) and specimens were preserved in formaline 5%. Then thay were identified to species level using the available identification keys. The 4 species were indentified as G. pseudosyriacus, G. proiectus, G. komareki, G. bakhteyaricus belonging to the genus Gammarus (Gammridae).

In this research the effects of 0.25, 0.5, 1 and 2mM pb(NO3)2 adjusted to pH 6 were examined on the four day old seedlings of Zea mays L. in the controlled condition for 72h. At the end of treatment the roots and shoots of seedlings were harvested separately.The length, dry weigh and fresh weigh of the roots and shoots of plants were measured.The results showed that Pb toxicity inhibits significantly root elongation and biomass. Analysing of Pb content in the roots and shoots of different treatments by atomic absorption indicated that: a)Pb absorption goes up by increasing level of Pb in growth solution; b) Pb accumulates in the roots and its transport to the shoots is very low. Determination of the amount of soluble sugars and total proteins indicated that the soluble sugars increased in the roots but their changes in shoots were not significant, while the total proteins were decreased in both roots and shoots. The profile of proteins by SDS-PAGE showed some changes related to control plants such as increasing of 56, 60 and 74 KD proteins.This research indicated that the Zea mays is a tolerant plant to Pb and takes up high levels of Pb from growth medium at pH 6. So, it would be necessary to understand the mechanisms of tolerance in this plant.

Anatomical differences between Iranian species of Aegilops can be used to separate morphologically similar species such as Ae. caudata and Ae. cylindrica, Ae. umbellulata and Ae. geniculata. Anatomical features like stomata subsidiary cells, degree of differentiation in mesophyll, presence of prickles, frequency of short cells in coastal and intercoastal parts, number of stomata rows, frequency of stomata and short cell per leaf area and some other characters are efficient in identification of closely related species as Ae. triuncialis, Ae. columnaris, Ae. kotschyii and Ae. neglecta. Leaf anatomical characters are very important in Aegilops taxonomy and could be applied in solving taxonomically problems of this genus.

In this experiment, the effect of inoculation of wheat cultivars with Azospirillum brasilense and pH of irrigation water on yield, protein content and sedimentation rate of protein (SRP) for wheat grain were examined. For this reason, a factorial experiment was conducted with three replicates and three cultivars of wheat (Omid, Ghods and Roshan), which were inoculated with and without Azospirillum brasilense. Irrigation water was applied into the pots during growing season with different levels of pH (7, 9 and 11). At the harvest time, the yield (grain) and nitrogen, protein content and SRP in grain were measured. The results indicated that the seed inoculation, pH of irrigation water and wheat cultivars have significant effect on the yield, protein content and SRP. Increase in the pH of irrigation water caused to decrease the yield, protein content and SRP. The maximum decline in the yield (17.2% decreases due a unit increase in pH), protein content and SRP due to the increase in irrigation water pH was observed in the Omid wheat cultivar (most sensitive cultivar), in contrast the Roshan wheat cultivar shows less adverse effect (10/7% decreases due a unit increase in pH). In inoculated treatments, all measurements were higher than non-inoculated pots. According to the results, Azospirillum can modify unfavorable conditions (higher pH) to obtain higher yield (by 10/7%), protein content (by 15.5%) and SRP (by 7.9%). However, the adverse effect of pH of irrigation water was the same in inoculated plants. From statistical point of view, the interaction of Azospirillum, wheat cultivar and pH of irrigation water had a significant effect on yield (grain) however the interaction for protein content and SRP were not significant. The interactions of each two treatments had statistically significant effect on yield, protein content and SRP; thereby more attention is needed for selection of Azospirillum stain and wheat cultivar.

β-glucan is a homopolymer of D-glucose residues which are linked through β-1,3 glycosidic bonds in the main chain. This polysaccharide, comprising the highest percentage of the fungal cell walls, has a major role in providing the cell wall with rigidity and protection. This is generally achieved through the assistance of other cell wall components, such as chitin and different proteins. β-glucanase enzymes degrade the polymer into its component residues by breaking the β-glycosidic bonds. As a producer of a variety of β-1,3 glucanase enzymes, the filamentous fungus Trichoderma, has become an important means of biological control for fungal diseases. In this study, after optimizing the glucanolytic conditions at both enzyme production and reaction stages for three randomly selected isolates, the glucanolytic activities of 30 Trichoderma isolates were assayed, leading to selection of the most and least active ones, T reesei with 22.07 U/mg and T. viridae 1 with 4.71 U/mg specific activity, respectively. In this regard, the T. reesei isolate, having the strongest β-1,3 glucanolytic activity among all isolates assayed, can be a nominee for further use as a biological control agent to protect against the fungal pathogens.