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  • Author or Editor: M. Yildiz x
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Effect of heat stress on the synthesis of soluble heat shock proteins (HSPs) and the regrowth in seminal roots of three cultivated and three wild wheat genotypes was examined. In regrowth experiments, 2-d-old etiolated seedlings were exposed to 23 (control), 32, 35, 37 and 38 °C for 24 h, and 35 and 37 °C (24 h) followed by 50 °C (1 h). The lengths of the seminal roots generally decreased significantly at the end of 48 and 72 h recovery growth periods at 35, 37 and 38 °C temperature treatments compared with control. Genotypic variability was significant level at all temperature treatments for the seminal root length. Also, genotypic differences for the number of seminal roots were determined among the wheat cultivars and between the wild wheat species and the wheat cultivars at all temperature treatments; but genotypic differences among wild wheat species were only detected at 37®50 °C treatment. Acquired thermotolerance for the seminal root length is over 50% at 37®50 °C treatment. The genotypic variability of soluble heat shock proteins in seminal root tissues were analyzed by two-dimensional electrophoresis (2-DE). Total number of low molecular weight (LMW) HSPs was more than intermediate- (IMW) and high- (HMW) HSPs at high temperature treatments. The most of LMW HSPs which were generally of acidic character ranged between 14.2-30.7 kDa. The genotypes had both common (43 HSP spots between at least two genotypes and 23 HSP spots between 37 and 37®50 °C) and genotype-specific (72 HSP spots) LMW HSPs.

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The effect of different chromium [Cr(VI)] concentrations (0, 75, 150 and 225 μM) on dehydrogenase activity, total soluble protein, proline, malondialdehyde (MDA) and antioxidant enzymes was investigated in the roots of two barley cultivars (Cr-tolerant Zeynelağa and Cr-sensitive Orza-96) in hydroponic experiments. The root dehydrogenase activity and protein content decreased with an increase in the Cr(VI) concentration, but no significant difference was found between the two barley cultivars. Cr(VI) stress increased the contents of proline and MDA in both cultivars, but this effect was more pronounced in Orza-96 than in Zeynelağa. The activities of antioxidant enzymes, including superoxide dismutase (SOD), ascorbate peroxidase (APX) and guaiacol peroxidase (POD), exhibited changes. The SOD activity increased in Zeynelağa and decreased in Orza-96 at 225 μM Cr(VI) compared to their controls. Cr(VI) stress decreased the APX and POD activities. Zeynelağa had greater APX activity than Orza-96 at 150 and 225 μM Cr(VI). However, there was no marked difference in POD activities between the two cultivars. The decrease in root dehydrogenase activity and protein content, the increase in proline and lipid peroxidation, and the alterations in the activities of antioxidant enzymes may be indicative of oxidative stress induced by Cr(VI).

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Growth, cell viability and heat shock proteins (HSPs) in Bezostaya-1, Çukurova-86 and Diyarbakır-81 cultivated wheat cultivars and three Aegilops species were investigated. Etiolated seedlings were exposed to 23 °C, 32 °C, 35 °C, 37 °C and 38 °C for 24 h, and 35 °C (24 h) → 50 °C(1 h) and 37 °C (24 h) → (50 °C (1 h). At the end of recovery growth periods, the shoot lengths of the genotypes generally decreased significantly at 35, 37 and 38 °C. The acquired thermal tolerance (ATT) in intact seedlings was over 50% at 35 °C → 50 °C and 37 °C → 50 °C, but in cell viability test it ranged from 2.75% (Ae. triuncialis) to 32.87 (Bezostaya-1) at 35 °C, and from 2.82% (Ae. triuncialis) to 37.82 (Bezostaya-1) at 37 °C. Ae. triuncialis was most sensitive genotype in both ATT determination. In electrophoretic profiles of proteins, while some HSPs were newly synthesized, some normal cellular proteins disappeared at 37 °C and 37 °C → 50 °C compared to 23 °C. The number of low molecular weight (LMW) HSPs were more than intermediate- (IMW) and high- (HMW) HSPs. The genotypes had both common (12 HSPs between at least two genotypes) and genotype-specific (33 HSPs) LMW HSPs. The common HSP of 19.8 kDa (pI 6.5) was synthesized in Bezostaya-1, Çukurova-86, Diyarbakır-81, Ae. biuncialis and Ae. umbellulata. Bezostaya-1 is the only genotype that synthesized 12 IMW and 2 HMW HSPs at 37 °C → 50 °C. Ae. triuncialis had only two common LMW HSPs [22.1 (pI 7.1) and 24.2 kDa (pI 6.5)].

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The seed germination of bread ( Triticum aestivum cv. Bezostaya 1 and Ceyhan 99) and durum ( Triticum durum cv. Diyarbakır 81 and Fırat 93) wheat species and their wild relative species ( Aegilops biuncialis and Ae. triuncialis ) was compared at two light levels, nine NaCl concentrations and three alternating temperature regimes. No seeds germinated at 675 mmol/L NaCl. The highest seed germination (100%) of cultivated wheat cultivars was noted in the control at 15/25°C and 20/30°C, and that of wild wheat species in both the control and the 150 mmol/L NaCl treatment under all temperature regimes. The seed germination of bread and durum wheat cultivars was completely inhibited at or above 450 and 375 mmol/L NaCl, respectively. No Ae. biuncialis seeds germinated at 600 mmol/L NaCl, while seeds of Ae. triuncialis germinated at this concentration (38.9%) only at 20/30°C in darkness. The inhibitory effect of light on germination in all genotypes was determined in some salinity levels at 15/25°C. The optimal germination treatment for all genotypes was 15/25°C temperature regime and darkness. The inhibitory effect of high salinity on germination was greater at 25/35°C than at 15/25°C or 20/30°C. In salinity and temperature interactions, the seeds of wild wheat species were found to be more tolerant than those of wheat cultivars.

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This study reports an anatomical study of the vascular supply in 20 Akkaraman sheep cerebelli from adult subjects of both sexes. The origin and branching pattern of the cerebellar artery vascularising the cerebellar nuclei were studied by gross dissection and vascular injection. Then dissection was performed and vessels nourishing the cerebellar nuclei were documented. Four bilaterally symmetrical cerebellar nuclei were determined as nucleus lateralis cerebelli, nucleus interpositus lateralis cerebelli, and nucleus interpositus medialis cerebelli and nucleus fastigii from lateral to medial side. It has been previously confirmed that vascularisation of the cerebellar nuclei is carried out by intermediary branches of the rostral cerebellar artery and the caudal cerebellar artery. However, this study has confirmed that the caudal cerebellar artery has no contribution in the vascularisation of the cerebellar nuclei.

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Arterial vascularisation of the ovine pineal gland was investigated by latex injection preparations of the common carotid artery in 20 adult Akkaraman sheep brains under stereo light microscope. It was observed that the arterial supply comes exclusively from branches of the caudal cerebral artery. The pineal gland was found to contain a rich vascular network. This network also received a few branches from the caudal choroid rami.

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Abstract  

In this work, Cs+ ion sorption on some clays and zeolite were investigated. 137Cs was used as a tracer. Activities were measured with a NaI crystal gamma counter. The particle size distribution was determined by a laser sizer. Surface area of the particles were determined by BET (Brunauer, Emmett and Teller method). Structure analysis was made by using X-ray diffraction. The chemical compositions of the solid samples were determined using a ICAP-OE spectrometer. Kinetic and thermodynamic parameters were determined. Due to very high uptake results; clay and zeolite can be proposed as a good sorbents in waste management considerations.

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Although immature embryos are the most suitable explants to regenerate cereals, their limited availability throughout the year hampers frequent experimentation. In order to circumvent this problem, endosperm-supported mature embryos, which are available throughout the year, are proposed for utilization in cereal tissue culture studies. In the present study, the effect of seed size on in vitro seed germination, seedling growth, callus induction and plant regeneration, as well as the relationships between these parameters, were investigated in three barley ( Hordeum vulgare L.) genotypes. Seeds were designated as large or small for each genotype and seed germinations were achieved in Petri dishes between two sheets of pre-wetted filter paper. Germination percentages of seeds, seedling growth rates, shoot and root lengths, and seedling fresh and dry weights were examined. Mature embryos from imbibed and dehulled seeds were aseptically moved slightly with a scalpel. For callus induction, 8 mg 1 −1 , 2,4-D dissolved in water, and for plant regeneration, hormone-free MS medium, was utilized. Highest values with respect to seed germination percentage, seedling growth, callus induction and plant regeneration were obtained using large seeds. Rooting of regenerated shoots and plantlet recovery were also successfully achieved. Based on the significant positive correlations observed between all parameters, we concluded that cultures derived from endosperm-supported mature embryos within large seeds should be employed for achieving superior tissue culture response.

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Authors: Serap Celikler, Sibel Tas, Sedef Ziyanok-Ayvalik, O. Vatan, Gamze Yildiz and M. Ozel

The presence of chromosomal damage in bone marrow cells affected by several diseases such as thyroid, cancer etc., was detected by the micronucleus (MN) assay. The present study was designed to evaluate: i) volatile components of Ulva rigida, ii) effects of hypothyroidism on bone marrow MN frequency, iii) effects of oral administration of Ulva rigida ethanolic extract (URE) on MN frequency produced by hypothyroidism, and iv) thyroid hormone levels in normal and 6-n-Propylthiouracil (PTU)-induced hypothyroid rats. The volatile components of Ulva rigida was studied using a direct thermal desorption (DTD) technique with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOF/MS). UREadministration was of no significant impact on thyroid hormone levels in control group, while PTU administration decreased thyroid hormone levels compared to control group (p < 0.001). Moreover, UREsupplementation resulted in a significant decrease in MN frequency in each thyroid group (p < 0.0001). This is the first in vivo study that shows the strong antigenotoxic and protective effect of UREagainst the genotoxicity produced by hypothyroidism.

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Authors: O. Temiz-Arpaci, T. Coban, B. Tekiner-Gulbas, B. Can-Eke, I. Yildiz, E. Aki-Sener, I. Yalcin and M. Iscan

The in vitro antioxidant properties of some new benzazole derivatives (1-10) such as benzoxazoles, benzimidazoles, and benzothiazoles were determined by their effects on the rat liver microsomal NADPH-dependent lipid peroxidation (LP) level, the scavenging of superoxide anion and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Compounds 1, 2, 4 and 6, showed potent scavenging effect on superoxide radical at 10-3 M. Compound 8, 5-nitro-2-(phenoxymethyl)benzimidazole, strongly inhibited lipid peroxidation at 10-3 M concentration.

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