نشریه علوم دانشگاه خوارزمی
سال چهارم شماره 3 (پاییز 1383)

Fetal DNA has been found in maternal plasma. Diagnosis of fetal gender using maternal plasma has been attempted in an effort to develop a new noninvasive method of prenatal diagnosis. We extracted DNA from plasma of 30 pregnant woman, three men, three non-pregnant women, and performed a sensitive Y-PCR assay to detect circulating male fetal DNA from women bearing male fetuses. Fetus-derived Y sequences were detected using 40 cycles of PCR carried out for each DNA extract. The PCR products were analyzed by 8% acrylamide gel electrophoresis and ethidium bromide staining, and the results were compared after delivery. Y sequences were detected in three control men and 14 pregnant woman who had a male fetus. Two samples from an eleven weeks and 19 weeks women bearing male fetuses gave negative result. None of 8 woman bearing female fetuses and none of the three non-pregnant control women gave a positive Y signal. In one sample from a 12 weeks woman bearing female fetus Y sequences was detected. Interpretation: Conventional PCR analysis of maternal plasma can be used to diagnose fetal gender after 19 weeks. Prenatal sex determination befor 15 weeks needs more sensitive methods such as Quantitative PCR.

Salicylic acid (SA) is a compound that has a basic role in increasing cold tolerance in plants. When two-days old radish seedlings were pretreated with different concentra-tions of SA (0, 0.5, 1, 1.5 and 2 mM) for 24 hours and then imposed to cold stress at 2.5 ˚C for 48 hours, cold resistance is increased in them. This phenomenon is shown by reduced efflux of K+ ions and soluble sugars and increased root length of seedlings especially at 0.5 mM, SA concentration. This finding shows that there is a straight correlation between SA concentration and reduced cold injury. Measuring the activity of three antioxidant enzymes, ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and catalase (CAT) in shoot and roots of radish seedlings, revealed that SA induced cold resistance is accompanied by increased activity of these antioxidant enzymes.

222 prespawning adult Acipenser persicus including 178 female and 44 male were sampled for studying the effect of temperature on the artificial breeding in the southeast of the Caspian sea during march 2000 – May 2001. The samples breeded in the shahid Marjany, sturgeon breeding and propagation center in Gorgan. In this study, the effect of temperature on fertilization percentage, the time of female sex ripering, positive feedback of broodstock to injection of pituitary studied. To study the effect of temperature on fertilization percentage, the time of female sex ripering, temperature groups divided into three groups and also to study the effect of temperature on the positive feedback of broodstock to injection on pituitary the temperature groups were divided into four groups. The highest fertilization percentage observed in 16.1-18°c. Increasing the temperature declined the time of female ripering of sexual maturity and positive feedback to pituitary injection

The protective functions that have been ascribed to anthocyanins in leaves can be performed as effectively as can be done by a number of other compounds. Daisy plants (Bellis perennis L.) accumulat the anthocyanin of cyanidine 3-malonyl-glucuronosyl-glucoside in their leaves in the response of salicylic acid and pathogens. Results showed that the different concentrations (3, 7, and 11μM) of salicylic acid were effective. Salicylic acid have significantly reduced disease severity and the concentrations of 11 and 3 μM salicylic acid of increased amounts of anthocyanins in infected plants by Fusarium sambacinum and Alternaria spp. It can be concluded that the effects of salicylic acid on daisy plants results in the increased amounts of anthocyanins and the decrease of disease symptoms.

Anthemideae is one of the largest tribes of Asteraceae. This investigation is based on a study on about 700 specimens belong to Anthemideae in Khorassan. During of this study two taxa were recorded, Tanacetum kotschyi, Achillea millefolium subsp. millefolium for the first time for the Flora of Khorassan, Iran.Tanacetum budjnurdense was collected after recording the sample type in 1950 from different location for the first time. Distribution maps and key to the genera and species occurring in Khorassan were finally provided

In this research work, porous silicon is made by using chemical method. Depending upon H.F density, the amount of porosity of silicon will change. Then an ohmic aluminium contact and gold contact on the porous side of silicon is made. I-V characteristics were plotted for different devices. Experimental results show that these devices are very sensitive with oxygen, so we can use these devices as oxygen sensor.

4-hydroxy-5-methyl-3, 4-diphenyl-2 cyclopentene-1-one 1 and 4-hydroxy-2-methyl-3, 4-diphenyl-2-cyclopentene-1- one 4 are prepared in short time using microwave. Dehydration of two diols 2 and 5 by HCl, only produces 2-methyl –3,4 diphenyl-2- cyclopentene-1- one 6. 2-methyl-3, 4-diphenyl-2-cyclopentene-1, 4- diol 5 was obtained from reduction of ketol 4 by NaBH4. Ketols 1 and 4 give Benzoic acid in presence of alkaline hydrogen peroxide