IRANIAN JOURNAL OF BIOLOGY
Year:2002 | Volume:12 | Issue:1-2|Papers Count:9

Decrease of ozon layer thickness and increase of ultraviolet radiations are some of the biological environmental problems emanated from human activities. High ultraviolet radiation B (280-320 nm , UV-B ) affects plants harmfully. Fennel is one of the precious medicinal plant, widely used in pharmacy, perfume, cosmetic and hygienic as well as food industries. The seeds or fruits of this plant have so much essential oils. Medicinal properties of these plant are attributed to this. essential oils. This research studies the anatomical structure, essential oils quality and quantity changes in fennel from umbeliferae family, all affected by high ultraviolet tradiation, emanated from a 40- watt lamp in the field conditions in three phases: before flowering, at flowering and after the formation of seed. Anatomical changes of treated plants radiated during all the phasses are including: inc easing of thickness of cuticular layer on adaxial epidermis in petiole, decreasing of palisade parenchyma tisssue (decrease in size and height of the cells). Increasing of surface of perivascular collenchyma tissue, and decreasing of their depth. Reduction in diameter of secretory canals and increase in thickness of stem selerenchyma cells. The amount of essential oils in leaf, stem, flower and seeds decreased in the most of phases, and essential oils components changed under ultravioler radiations. The amount of trans nethole. The most important compound of this essential oil, has offen decreased but Estragol, Fenchone and Limonene showed an increase, in most cases. The above results indicated the sensitivity of fennel to ultraviolet radiations.

Hydrocarbons and hydroxy-fatty acids are two main components of wax in Euphorbia larica The major hydrocarbons compounds of the wax are including pentacosane, heptacosane and nonacosane. The fatty acid fraction of the wax are consisted of hydroxy-acids such as 2-methyl-2,2-dimethyl-1,1- (2-hydroxy)-1-propanoic acid and 2-methyl -1,3-hydroxy-2,4,4-trimethylene propanoic acid.

Rotavirus infection is the major etiological agent of severe diarrhea in infant and young children. Nonstructural glycoprotein NSP4 of Rotavirus and its epitope (amino acids 114-135). which act as enterotoxin are considered in vaccine development against Rotavirus. Coli surface antigen 3 (CS3) pili of Enterotoxigenic Escherichia coli (ETEC) can be used as a system for expression of foreign antigenic determinants on the bacterial surface. In this study, cDNA encoding for NSP4114-135 was amplified by PCR and after digestion with endonuclease StyI was cloned in cstH gene encoding structural subunit of CS3 fimbriae. Recombinant plasmids were screened by PCR, restriction enzyme analysis, DNA hybridization and DNA sequencing. Hybrid gene, cstH:: nsp4114-135 was then cloned in the expression vector pET21a(+) under the control of T7 promoter. Expression of hybrid protein CSTH:: NSP4114-135 in E.coli DH5α was indicated by SDS PAGE and Western blot analysis using antibodies against CS3 and NSP4. Expression of hybrid protein on the surface of E.coli as chimeric pili and its immunogenicity are currently under investigation.

It is necessary to mention that among sea foods shrimp involves special position. Fortunately, Iran has got the best situation to grow up shrimp in recent years and try to produce it as much as possible. The impact of protector substance sodium diacetate on some microbes and also the qualification of shrimp were considered in this investigation. In first step, less preventive substance sodium diacetate on proteolytic, psychrophilic bacteria (Pseudomonas and Aeromonas) was estimated by pourplate method. In second step, bacterial flora and proteolytic, psychrophilic bacteria (Pseudomonas aeruginosa, Pseudomonas flourescens, and Aeromonas) calculated and identified by selective medium .and different tests, meanwhile, less preventive substance sodium diacetate 4 and 5 g/I individually and another one was also left without down countable, proteolytic, psychrophilic bacteria and the rate of volatile nitrogen (TVN) in special period of the experiments on 0, 3, 5, 7, 14, 21, 30. All experiments have pointed out that less preventive substance sodium diacetate is 4 g/I. Also the deduction of countable bacteria and the qualification of shrimp pointed out that the numbers of bacteria and the rate volatile nitrogen in shrimp sample which were left in 4 and 5 g/l sodium diacetate had less bacteria than the first witness sample and during a period about 30 days, it was almost nothing. Reduce bacteria were more by increasing in sodium diacetate. The percent of volatile nitrogen in samples that were left in sodium diacetate was less in considering with witness sample. In short, the protector substance sodium diacetate keeps the value of the shrimp as a kind of long life food and its healthy in -20°C and increased the time of their usage.

Atherosclerosis is one of the coronary-heart diseases which is associated with diabetes. The metabolism of lipids and carbohydrates is alerted in atherosclerosis and diabetes. Therefore, an appropriate animal model could be useful in analyzing the mechanisms involoved in the initiation of atherosclerosis in diabetes. In this study, the atherosclerosis indices were analyzed in rat following induction of diabetes using. Alloxan monohydrate. Examination of low density lipoprotein (LDL) in diabetic animals showed a marked increase compare with control group (p =0.007). Analysis .of plasma high density lipoprotein (HDL) as another factor involved in atherosclerosis, demonstrated a sharp in diabetic animals compared to the control group (p =0). Furthermore, analysis of the concentration of triacylglycerol in plasma indicated a significant increase in diabetic condition compared to the normal condition in control groups. In contrast, the plasma cholestrol level did not show any significant changes, which could be related to the self regulatory mechanisms controlling its plasma concentration. Examination of the weight of the spleen showed an increase in diabetic animals compared to the control group, suggesting the presence of increased stimulation of the immune system. This indicated that atherosclerosis was associated with autoimmunity. Together, the data from this study suggested that diabetes induced by Alloxan could .be used as an animal model for studying the mechanisms involved in atherosclerosis.

In this article, the karyotypic characters of the Iranian species of the Bromus belonging to the section Genea Dumort. have been studied. The mature seeds were collected .during different field trips by author and other botanists from, different regions of Iran. Root meristems, after pretreatment by ice water or colchicine, solution, were fixed in Carnoy's fixative. The root tips, after hydrolysis by N HCl at the temperature of 60°C, were stained in a mixture of 2% acetoorcein and Schiff's reagent. Microscopic preparations were made in acetoorcein. At least, 10 metaphase plates have been .studied for each species. The following measurements were done: Total length of individua; chromosomes (t), Length of longer arm of each chromosomes (I), Length of shorter arm of each chromosomes (s). Then, the karyotypic indicators were calculated. The idiograms of species were drawn. Furthermore, by using Levan et al. method, the centromer position of the chromosomes and karyotypic formulae and according to the two way systems of Stebbins, Karyotypic symmetry have been determined. By using statistica software and performing UPGMA and Ward's method clustering, the affinity of the species was studied and the results were presented in dendrograms. This study shows that the basic chromosome number in this group (x) is equal to 7. From the taxa studied, B. Madritensis L. and B. rubens L. are tetraploids, while B. fasciculatus Presl, B. sericeus Drobov, B. sterilis L. and B. tectorum L. are diploids. The karyotype of these species has been drawn. Taking into consideration of morphologic variations and geographic distribution, the relationship of the -taxa have been discussed. These results confirm, more or less, the results of our previous study of phenetic analysis in this group.

In the persence of heavy metals in soils, plants responses are various. Cadmium as a heavy metal induced seriour symptoms in plants such as growth retardation, root damahes, alternation in plasma membrane properties, changing enzyme activities and the amount of antioxidant compounds. In this study the effects of various concentrations of cadmium chloride on growth parameters and physiological processes of canola seedlings were investigated. Seeds were germinated-on filter paper in Petri dishes containing various concentration of Cd2+. After a week identical seedlings selected and then analyzed. The obtained results show significant decrease in root growth, root elongation and total chlorophyll contents, especially in higher cadmium ion concentration. It seems that chlorophyll decreasing could be from direct effect of cadmium ions on chlorophyll synthesis. Cd2+ absorption by root and Cd2+transport in xylem and its accumulation in leaves caused significant increased lipid peroxidation in root and leaf. It happened because of high susceptibility of double bounds of lipids in memberane ehich is reactive to oxygen species (ROS) and increasing activeity of peroxidase. The seedlings sublected to high level 06 Cd2-showed decrease in ascorbate (ASe) / dehydroascorbate (DHA) ratio while total ascorbate concentration did not show remarkable changes in comparison to controls. The results suggested that growth retadation is because of direct effect of cadmium ion on cell growth and cell division. This is because of high tedency of cadmium ion to solfhydry groups or the indirect effect of cadmium ion via reactive oxygen species (ROS) formation. Red-brown coloration of merlstemic and elongation zone could possibly be the increase activation of peroxidase enzymes. In the other hand, it seems that growth retardation may caused because of impaired ascorbate - glutathion .cycle activity in high cadmium concentation . Decrease in ascorbate content is caused from glu tathion (GSH) impotring to GSH pool for phytochelation synthesis and decreased ascorbate as reduction substrate. However, synthesis of ascorbate, ascorbate peroxidase, monodehydroascorbate reductase and glutathion reductase is stimulated in lower concentration of cadmium ion which inceases in GSH cycle activity and detoxification of ROS.