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2000

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Articles 2071 - 2100 of 2418

Full-Text Articles in Life Sciences

In Situ Germination Of Pollen Tetrads In Periplocagraceae L. (Periplocaceae), Feruzan Dane Jan 2000

In Situ Germination Of Pollen Tetrads In Periplocagraceae L. (Periplocaceae), Feruzan Dane

Turkish Journal of Biology

The mature anthers in large flower buds of Periploca graceae L. ( Periplocaceae ) were examined cytologically. It was seen that pollen was retained in permanent tetrads. Pollen tetrads were usually observed as isobilateral, rarely as linear. It was also observed that pollen tetrads germinated within the anther loculi. Most of the pollen tetrads were well stained and the germination rate was 90 %. In in situ germinated pollen tetrads, 1-4 pollen tubes were observed. During germination of pollen tetrads, the behavior of the nuclei was normal. At the early stage of pollen tube formation, a vegetative nucleus and two …

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Isolation, Characterization And Identification Ofthiram-Degrading Microorganisms From Soilenrichment Cultures, Nuretti̇n Şahi̇n, Abdurrahman Üsame Tamer Jan 2000

Isolation, Characterization And Identification Ofthiram-Degrading Microorganisms From Soilenrichment Cultures, Nuretti̇n Şahi̇n, Abdurrahman Üsame Tamer

Turkish Journal of Biology

Mixed microbial cultures were obtained by enrichment from soil samples collected from the Gediz basin. A number of species of bacteria and fungi were isolated and partially characterized from enrichment clutures containing the fungicide thiram. According to their responses in morphological and biochemical tests fungi were identified as Aspergillus niger, A. flavus and Penicilium steckii. Bacterial isolates were assigned to the genera: Bacillus, Arthrobacter, Moraxella-like Acinetobacter and Streptomyces. Islates grew in a mineral salts medium containing 0.2 mg/ml thiram and no growth factors were required.

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Pollen Characters And Their Evolutionarysignificance With Special Reference To The Flora Ofkarachi, Anjum Perveen Jan 2000

Pollen Characters And Their Evolutionarysignificance With Special Reference To The Flora Ofkarachi, Anjum Perveen

Turkish Journal of Biology

The pollen morphology of 353 species from Karachi, belonging to 67 families of angiosperms, distributed in 58 dicots and 9 monocots were investigated by scanning electron microscope (S.E.M.) and light microscope (L.M.). Examination of these families revealed great pollen diversity in their qualitative and quantitative characters. However, from a phylogenetic and evolutionary point of view, polarity, symmetry, apertural types and exine sculpturing are the most important characters. In general, dicot pollen is relatively more specialized than that of monocots. Dicotyledons are generally characterized by radially symmetrical, isopolar, colporate, colpate and porate pollen, whereas monocotyledon are usually heteropolar, bilaterally symmetric, boat-shaped, …

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A Study Of The Levels Of Vitamins A, E And C And Selenium In Rhubarb(Rheum Ribes L.), Ömer Munzuroğlu, Fi̇kret Karataş, Nazmi̇ Gür Jan 2000

A Study Of The Levels Of Vitamins A, E And C And Selenium In Rhubarb(Rheum Ribes L.), Ömer Munzuroğlu, Fi̇kret Karataş, Nazmi̇ Gür

Turkish Journal of Biology

The levels of vitamins A, E and C and selenium in young shoots of Rheum ribes L. collec-ted at various altitudes from Elazığ and Tunceli Basins were examined experimentally. The vitamin le-vels and the amount of selenium were determined by HPLC and fluorometers. It was determined that the levels of A, E and C vitamins and selenium in the young shoots of Rheum ribes L. were in the ranges of 0.255 ± 0.019 - 0.363 ± 0.015 µg.gr -1 , 0.614 ± 0.014 - 0.765 ± 0.021 µg.gr -1 , 197.6 ± 10.47 - 282.3 ± 17.46 µg .gr -1 …

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Identification Of Lactoce Plasmids In Lactococcus Lastic Subsp. Lactisstains, Çağla Tükel, Mustafa Akçeli̇k Jan 2000

Identification Of Lactoce Plasmids In Lactococcus Lastic Subsp. Lactisstains, Çağla Tükel, Mustafa Akçeli̇k

Turkish Journal of Biology

Plasmids encoding lactic acid fermentation ability were investigated in 50 strains of L. lactis subsp. lactis. Acriflavine was used for the elimination of lactose fermentation ability (Lac + ) from wild type strains. Lactose negative (Lac - ) mutants were selected on lactose indicator agar media. Six different lactose plasmids were identified for fifty strains by comparison of plasmid profiles of Lac - and Lac + mutants. The molecular sizes of these lactose plasmids ranged between 26.3 and 38.5 kb.

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Phage Sensitivities Of Lactococci Isolated From Raw Milk And Whey, Pinar Şanlibaba, Mustafa Akçeli̇k Jan 2000

Phage Sensitivities Of Lactococci Isolated From Raw Milk And Whey, Pinar Şanlibaba, Mustafa Akçeli̇k

Turkish Journal of Biology

In this study, lactococcal strains isolated from raw milk and whey samples of different types of cheese produced without using industrial starter cultures in different regions of Turkey were tested for sensitivity to 22 lactic phages. In addition to the strain isolation materials, virulent lactic phages were also isolated from samples obtained from dairy plants using industrial starter cultures. 18 L lactis subsp. lactis strains out of 73 lactococcal strains were found to be resistant to all the phages. It was determined that the total phage resistance levels of the other 55 strains were between 18.18 and 90.90%.

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Insecticide Resistanca In Maleria Vector An. Sacharovi, Ümi̇t Lüleyap, Hali̇l Kasap Jan 2000

Insecticide Resistanca In Maleria Vector An. Sacharovi, Ümi̇t Lüleyap, Hali̇l Kasap

Turkish Journal of Biology

Susceptibility tests have been successfully used for many years to determine insecticide resistance raised in pest and vector insects, including An. sacharovi,the primary human malaria vector in Turkey. As this method does not provide sufficient information about physiological resistance, an alternative method of enzyme tests based on biochemical and genetic evaluations has been developed. In this study, both methods were used for comparison. First of all, susceptibility to insecticides was tested in adult females of An. sacharovi collected in different seasons from Tabaklar and Herekli Villages, where insecticides are used intensively for both agricultural and vector control purposes, and from …

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Investigation On The Liver Functions Agriculturel Workers Chronically Exposed To Pesticides, Ülkü Çömelekoğlu, Bi̇rgül Mazmanci, Abdullah Arpaci Jan 2000

Investigation On The Liver Functions Agriculturel Workers Chronically Exposed To Pesticides, Ülkü Çömelekoğlu, Bi̇rgül Mazmanci, Abdullah Arpaci

Turkish Journal of Biology

Blood samples were taken from agricultural workers who had been exposed to pesticides for long periods in Içel and the surrounding agricultural areas (n=150) and levels of AST, ALT, ALP, LDH, total protein, albumin and globulin in serum were determined. The same parameters were measured in 64 persons who are not exposed to pesticides in any way. Study group showed significantly higher levels of AST, ALT, ALP and LDH (p

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Immunohistochemical Distribution Of Transforming Growth Factor Alpha,Laminin, Fibronectin And Desmin In Rat Ovary, Gökhan Akkoyunlu, İsmai̇l Üstünel, Ramazan Demi̇r Jan 2000

Immunohistochemical Distribution Of Transforming Growth Factor Alpha,Laminin, Fibronectin And Desmin In Rat Ovary, Gökhan Akkoyunlu, İsmai̇l Üstünel, Ramazan Demi̇r

Turkish Journal of Biology

Since the pure synthesis of transforming growth facto alpha (TGF\alpha) many attempts have been made in order to determine its distribution in various tissues. As a result of the complexitiy of the cyclic periods throughout experimental models, it is not easy to determine the distribution of TGF\alpha in the system. Especially the pre-and through-gestational pattern of TGF\alpha in rat ovary has not been reported fully. Furthermore, the shortage of literature about intracellular desmin and laminin, fibronectin of different intermediate filaments whether they have any interaction with TGF\alpha through this period, makes the subject worth discussing. Immunocytochemical techniques were utilized in …

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Erythrocyte Superoxide Dismutase And Catalase Activities In Agricultureworkers Who Have Been Chronically Exposed To Pesticides, Ülkü Çömelekoğlu, Bi̇rgül Mazmanci, Abdullah Arpaci Jan 2000

Erythrocyte Superoxide Dismutase And Catalase Activities In Agricultureworkers Who Have Been Chronically Exposed To Pesticides, Ülkü Çömelekoğlu, Bi̇rgül Mazmanci, Abdullah Arpaci

Turkish Journal of Biology

Blood samples were taken from farmworkers (n=40) who had been long-term exposed with pesticides (16.52±6.92 years) in Içel and surrounding agricultural areas and measured erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities were measured using spectrophotometric assignation. These antioxidant enzymes were also evaulated in people who had not been exposed to pesticides (n=30). It was observed that erythrocyte SOD levels were significantly higher (p

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Some Kinetic Properties Of Hepatic Lipase Of Oncorhynchus Mykisswalbaum, 1792, Kubi̇lay Meti̇n, Mehmet Ali̇ Akpinar Jan 2000

Some Kinetic Properties Of Hepatic Lipase Of Oncorhynchus Mykisswalbaum, 1792, Kubi̇lay Meti̇n, Mehmet Ali̇ Akpinar

Turkish Journal of Biology

Some kinetic properties of hepatic lipase of Oncorhynchus mykisswere investigated. Hepatic triacylglycerol lipase was found to be located in the cytosolic fraction of the cell. Optimal activity of hepatic lipase occurred at pH 8.00 and 32 °C. When pNPA was used as a substrate, Vmax and Km values of hepatic lipase were estimated as 0.40 U/mg protein and 0.12 mM pNPA respectively. A stimulating effect of monovalent (NaCl and KCl) and divalent (CaCl 2 and MgCl 2 ) metal ions on hepatic lipase activity was determined. The bile salts, Na-taurodeoxycholate and Na-deoxycholate, were determined to inhibit hepatic lipase activities. A …

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Studies On Genetic And Breeding In Sesame ( Sesamum Indicum L.)I. Inheritance Of The Characters Determining The Plant Type, Hasan Baydar, İsmai̇l Turgut Jan 2000

Studies On Genetic And Breeding In Sesame ( Sesamum Indicum L.)I. Inheritance Of The Characters Determining The Plant Type, Hasan Baydar, İsmai̇l Turgut

Turkish Journal of Biology

The inheritance of the morphogenetical characters determining the plant types, maternal and cytoplasmic effects on oleic and linoleic acids in sesame was determined. The results obtained from the F 1 generation indicated that 1) bicarpellate capsule was dominant over quadricarpellate, 2) single capsule per leaf axil was dominant over three-capsule 3) branched stem type was dominant over non-branched stem type, 4) lobed leaf shape was dominant over simple or ovate leaf shape, 5) hairiness was dominant over hairless, 6) colored seed coat color was dominant over white seed coat color. The results obtained from the F 2 generation indicated that …

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Production Of Gibberellic Acid And Cytokinin By Phanerochaete Chrysosporiumme446 Immobilized On Polyurethane Foam, Serpi̇l Ünyayar Jan 2000

Production Of Gibberellic Acid And Cytokinin By Phanerochaete Chrysosporiumme446 Immobilized On Polyurethane Foam, Serpi̇l Ünyayar

Turkish Journal of Biology

The fungus Phanerochaete chrysosporium ME446 was entrapped on polyurethane foam to synthesize gibberellic acid (GA 3 equivalent) and Cytokinin (zeatin equivalent). Maximum gibberellic acid was defined on the 6 th day (44.43 µg/mL and 61.22 µg/mL, respectively) in both free and immobilized cells. Maximum cytokinin was defined on the 12 th day (9.61µg/mL and 16.33 µg/mL, respectively) in both free and immobilized cells. An immobilized system of gibberellic acid and cytokinin production resulted in comparatively higher yield than free fungal mycelium.

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Eukaryotic Transcriptional Regulatory Proteins, Kemal Büyükgüzel Jan 2000

Eukaryotic Transcriptional Regulatory Proteins, Kemal Büyükgüzel

Turkish Journal of Biology

Transcriptional regulation is of considerable importance in the expression of eukaryotic genes, and a considerable degree of regulation is controlled at the level of mRNA synthesis. As in prokaryotic organisms, transcriptional control in eukaryotes results from an interplay between regulatory DNA sequences and site-specific DNA-binding proteins. Transcription of eukaryotic genes is influenced by various regulatory elements, termed promoters, enhancers and silencers. These regulatory elements are composed of discrete DNA sequences, which constitute binding sites for sequence-specific DNA-binding proteins. These proteins bind DNA by some common structural motifs. The motifs that are utilized by eukaryotic regulatory proteins are helix-turn-helix, zinc finger …

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The Effects Of Different Carbon Sources And C/N Ratio On Microbialdenitrification, Gülten Ökmen Kurucuoğlu, Ömer Faruk Algur Jan 2000

The Effects Of Different Carbon Sources And C/N Ratio On Microbialdenitrification, Gülten Ökmen Kurucuoğlu, Ömer Faruk Algur

Turkish Journal of Biology

The effects of different carbon sources (ethanol, methanol and acetic acid) and C/N ratios (0,5; 1; 1,5; 2; 2,5) on the microbial denitrification in batch culture were investigated. For this purpose Paracoccus denitrificans and Pseudomonas stutzeri were used as denitrifiers. For all experiments, the initial NO 3 concentrations were constant at 100 mg/l. During the incubation period of 66 hours, nitrate, nitrite and microorganism concentrations were determined spectrophotometrically at certain intervals. When ethanol was used as a carbon source, the highest NO 3 reductions for P. denitrificans and P. stutzeriwere found to be 40% (C/N = 1) and 32% (C/N …

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Population Dynamics Of Horse Mackerel (Trachurus Trachurus L., 1758)Stocks In The Mid Black Sea, Turkey, Şennan Yücel, İbrahi̇m Erkoyuncu Jan 2000

Population Dynamics Of Horse Mackerel (Trachurus Trachurus L., 1758)Stocks In The Mid Black Sea, Turkey, Şennan Yücel, İbrahi̇m Erkoyuncu

Turkish Journal of Biology

The aim of the present study, which was carried out on 720 individuals between October 1995 and September 1996 in the mid Black Sea region was to estimate some parameters of the population of horse mackerel (Trachurus trachurus L. 1758) including age, size, weight, sex compositions, growth and mortality rates. Ages between 0 and 7 were established in horse mackerel stock. The weight-length relationship was calculated as; W= 0.00759L 3.05 , condition factor 0.843 and the Von-Bertalanffy growth formulas were, Lt= 16.92 (1- -0.3538 (t+2.7938) ) Wt= 47.11 (1-e -0.3538 (t+2.7938) ) 3.05 . Instantaneous total mortality coefficient, natural mortality …

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Cytogenetic Effects Of Copper Chloride On The Root Tip Cells Of Viciahirsuta (L.) S. F. Gray, Hüseyi̇n İnceer, Osman Beyazoğlu Jan 2000

Cytogenetic Effects Of Copper Chloride On The Root Tip Cells Of Viciahirsuta (L.) S. F. Gray, Hüseyi̇n İnceer, Osman Beyazoğlu

Turkish Journal of Biology

The cytogenetic effects of copper chloride on root tip cells of Vicia hirsuta were investigated. Seeds were treated with 10, 25, 50 and 100 mg/L of the copper chloride for 4, 12, 24 and 48 hours. It was found that copper chloride has a marked mitodepressive action on mitosis. Mitotic abnormalities were increased and the mitotic index was decreased depending on the concentration and duration time of the copper chloride applied.

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Fungal Contamination And The Incidence Of Ochratoxin-A In Some Cerealsand Products, Nural Kargözlü, Mehmet Karapinar Jan 2000

Fungal Contamination And The Incidence Of Ochratoxin-A In Some Cerealsand Products, Nural Kargözlü, Mehmet Karapinar

Turkish Journal of Biology

One hundred samples (wheat, corn, corn flour, oat, oat flour, muesli) were analysed for ochratoxin-A and fungal contamination. Ochratoxin-A was detected in four samples at the level of 0.27-9.84 ppb in one wheat, two corn and one oat flour samples. Total mould and yeast counts were detected to be 20-

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The Effect Of Cadmium Nitrate On Some Developmental Properties Ofdrosophila Melanogaster, Lütfi̇ye Gelegen, Eli̇f Yeşi̇lada Jan 2000

The Effect Of Cadmium Nitrate On Some Developmental Properties Ofdrosophila Melanogaster, Lütfi̇ye Gelegen, Eli̇f Yeşi̇lada

Turkish Journal of Biology

The effects of cadmium nitrate on the fecundity, larval survival and sex ratio of D. melanogaster were tested. According to our findings, the effects of cadmium nitrate can be summarized as follows: it appeared that when used as a feeding substance during the developmental period, cadmium nitrate did not have any effect on fecundity. On the other hand, if cadmium nitrate was given throughout adult life it caused a proportional decrease in the daily mean with increasing concentration. Furthermore, the larval survival ratio decreased due to the concentration of cadmium nitrate. Also cadmium nitrate application appeared to have no effect …

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The Effect Of Cadmium Nitrate On The Longevity Of Drosophilamelanogaster, Eli̇f Yeşi̇lada, Lütfi̇ye Gelegen Jan 2000

The Effect Of Cadmium Nitrate On The Longevity Of Drosophilamelanogaster, Eli̇f Yeşi̇lada, Lütfi̇ye Gelegen

Turkish Journal of Biology

The effect of cadmium nitrate on the longevity of Drosophila melanogaster was tested. When cadmium nitrate was given throughout the adult life it caused a decrease in the mean life-span of flies in all treated groups. Furthermore, the effect of cadmium nitrate on young populations was also compared with aged populations. The young populations survived longer than aged populations with the food medium containing cadmium nitrate.

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The Isolation And Characterization Of Glucoamylase Enzyme Of Anaspergillus Niger Natural Isolate, Gökhan Coral, Ömer Çolak Jan 2000

The Isolation And Characterization Of Glucoamylase Enzyme Of Anaspergillus Niger Natural Isolate, Gökhan Coral, Ömer Çolak

Turkish Journal of Biology

An extracellular glucoamylase enzyme was isolated from Aspergillus niger Z10 natural isolate in a liquid Czapek Dox medium which contained soluble starch (2%) as the sole carbon source. The molecular weight of the enzyme was found to be about 100.000 Daltons through Starch-SDS Polyacrylamide Gel Electrophoresis. The optimal pH range of the enzyme was found to be 4.5-5.5 and it was determined that the thermal stability of this enzyme is quite high.

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Obtaining Biosurfactant From Olive Oil Mill Effluent (Oome) Usingpseudomonas Sp., Uğur Sidal, Nazi̇f Kolankaya, Cengi̇z Kurtonur Jan 2000

Obtaining Biosurfactant From Olive Oil Mill Effluent (Oome) Usingpseudomonas Sp., Uğur Sidal, Nazi̇f Kolankaya, Cengi̇z Kurtonur

Turkish Journal of Biology

Olive oil mill effluent (OOME) is one of the major pollutants produced by the agricultural industry in Mediterranean countries. The olive oil mills in these countries generate about 2-3 million tonnes of effluent annually. OOME is a black liquor containing a water-soluble fraction of ripe olives and water that is used in the process of olive oil extraction. This waste has a high mineral content and a chemical oxygen demand of 25.000-100.000 mg/l. depending on the olive oil extraction process used. This study presents a process for biosurfactant as rhamnolipid production by Pseudomonas sp. from olive oil mill effluent (OMME). …

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The Seasonal Variation In Total Lipid And Fatty Acid Contents Of Thegonads Of Cyprinion Macrostomus (Heckel, 1843), Kubi̇lay Meti̇n, Mehmet Ali̇ Akpinar Jan 2000

The Seasonal Variation In Total Lipid And Fatty Acid Contents Of Thegonads Of Cyprinion Macrostomus (Heckel, 1843), Kubi̇lay Meti̇n, Mehmet Ali̇ Akpinar

Turkish Journal of Biology

The seasonal variation in total lipid and total fatty acid contents of the gonads of Cyprinion macrostomus(HECKEL, 1843) living in the Topardiç Brook (Kangal-Sivas) were investigated. It was observed that the variations in the gonad weights and the amount of total lipid and total fatty acid in the gonad of the male and female fish were more noticeable especially at the time of gonad development and the spawning period. The total lipid and total fatty acid amount which increased during the spawning period showed a decrease at the end of this period.

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Study Of Adventitious Shoot Formation In Leaves Of Grape (Vitis Spp.), Ni̇lgün Göktürk Baydar Jan 2000

Study Of Adventitious Shoot Formation In Leaves Of Grape (Vitis Spp.), Ni̇lgün Göktürk Baydar

Turkish Journal of Biology

The effects of genotype, source of explant and nutrient medium on adventitious shoot formation were examined in the leaves of 5 grape cultivars (Atasarisi, Çavus, Kalecik Karasi, Sultani çekirdeksiz and Yapincak), 2 rootstocks (Kober 5BB ( V. berlandieri x V. riparia) and 41 B M.G. (Chasselas x V. berlandieri)) by organogenesis. In this study, petioles and laminae isolated from in vitro shoots were used as the sources of explant. The highest rates of adventitious shoot formation were obtained from petiole explants. Leaf explants were cultured on MS- and NN- based regeneration media containing different concentrations of BAP and NAA. It …

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Karyotype Analysis In Chalcalburnus Mossulensis (Heckel, 1843), Süleyman Gül, Ahmet Çolak, İlhan Sezgi̇n Jan 2000

Karyotype Analysis In Chalcalburnus Mossulensis (Heckel, 1843), Süleyman Gül, Ahmet Çolak, İlhan Sezgi̇n

Turkish Journal of Biology

Karyotype analysis was performed in Chalcalburnus mossulensis (Heckel, 1843) belonging to the carp family by investigating the number and structures of their chromosomes. The fish used in this study were caught with fishing nets from Kizilirmak river and taken to the laboratory. They received an abdominal injection of 0.6 mg colchicine (Colchicum Dispert) dissolved in 1 ml of distilled water per 1 g body weight. As a result of the C-metaphase investigation, it was determined that C. mossulensis had 2n=48 chromosomes. Their karyotypes were determined to be composed of 6 metacentric, 10 submetacentric, and 8 acrocentric chromosome pairs. We were …

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Boron Accumulation In Carp Tissues ( Cyprinus Carpio L., 1758) In Damlakes Çötören And Kunduzlar (Kırka-Eskişehir), Şaki̇r Özkurt Jan 2000

Boron Accumulation In Carp Tissues ( Cyprinus Carpio L., 1758) In Damlakes Çötören And Kunduzlar (Kırka-Eskişehir), Şaki̇r Özkurt

Turkish Journal of Biology

Samples of water, bottom clay, plankton and fish were collected over a period of one year. The boron contents of the samples taken were determined in the laboratory. The differences and relationships in the obtained data were identified using various statistical methods. Boron gradually accumulates in the plankton, bottom clay and water of Çatören and Kunduzar. Boron collects in the tissues of the fish Cyprinus carpio in both lakes, in the musce, brain and liver in Çatören, and in the musce, liver and brain in Kunduzlar. Boron pollution is more serious in Çatören dam than in Kunduzlar. It was observed …

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The Effects Of Heavy Metals On The Pollen Germination And Pollen Tubegrowth Of Apples (Malus Sylvestris Miller Cv. Golden), Ömer Munzuroğlu, Nazmi̇ Gür Jan 2000

The Effects Of Heavy Metals On The Pollen Germination And Pollen Tubegrowth Of Apples (Malus Sylvestris Miller Cv. Golden), Ömer Munzuroğlu, Nazmi̇ Gür

Turkish Journal of Biology

The effect of heavy metals, namely mercury (Hg^{+2}), zinc (Zn^{+2}), nickel (Ni^{+2}) and cobalt (Co^{+2}), which were applied in the form of chloride salt, and that of lead (Pb^{+2}) and cadmium (Cd^{+2}) applied in the form of nitrate salt, on the pollen germination and tube growth were investigated on apples ( Malus sylvestris cv. Golden). According to the results obtained, these heavy metals led to a significant decrease in the pollen germination and tube growth. It was found that there was a parallelism between the concentration of heavy metal salt, and pollen germination and tube growth. Among the heavy metals …

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Prevention Of Hydrogen Peroxide And Cisplatininduced Apoptosis By Intracellular Catalaseoverexpression, H. Barbaros Oral, Andrew J.T. George, Dorian O. Haskard Jan 2000

Prevention Of Hydrogen Peroxide And Cisplatininduced Apoptosis By Intracellular Catalaseoverexpression, H. Barbaros Oral, Andrew J.T. George, Dorian O. Haskard

Turkish Journal of Biology

Apoptosis induced by hydrogen peroxide (H_2O_2 ) was investigated in Chinese hamster ovarian (CHO) cells, and compared to apoptosis induced by cisplatin (25 µM), a well-established apoptosis-inducing agent. In preliminary experiments, CHO cells were treated with low concentrations of H_2O_2 (250-500 µM) continuously or for 3 hours, followed by washing and further incubation in complete growth medium for 1-10 days. Fluorescence microscopy of acridine orange-stained cells indicated morphological changes of apoptosis. Similar changes were observed in cisplatin-treated cells. DNA-laddering also revealed that DNA fragmentation occurred in both adherent and non-adherent cells by day 2. To prevent H_2O_2 -mediated apoptosis, the …

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Production Of Monoclonal Antibodies Specific Forprogesterone, Estradiole By Simultaneous Injectionof Different Steroids, Fatma Şahi̇ngöz Yücel, Beyazit Çirakoğlu Jan 2000

Production Of Monoclonal Antibodies Specific Forprogesterone, Estradiole By Simultaneous Injectionof Different Steroids, Fatma Şahi̇ngöz Yücel, Beyazit Çirakoğlu

Turkish Journal of Biology

We report here the development of hybrid cells producing monoclonal antibodies specific for two different steroid hormones with mixed immunization using hybridoma technology. BALB/c mice were immunized with a mixture of three steroid antigens: progesterone, estradiole and testosterone linked to bovine serum albumine. These mice were used for fusion. In the two fusion experiments, ELISA tests showed that among 645 wells only 2 hybrids reacted with progesterone (MAM 3C2, MAM 3E3) and one of them reacted specifically with estradiol (MAM 7H7). Three types of monoclonal antibodies were detected: IgG1, IgG2a and IgG2b and the affinities of these antibodies were found …

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Effects Of Ph On The Genesis Of Membrane Potentialchanges At Fertilization In The Egg Of The Frog Ranacameranoi, Şeref Erdoğan, Gülay Loğoğlu, Kerem Tuncay Özgünen, Tuncay Özgünen Jan 2000

Effects Of Ph On The Genesis Of Membrane Potentialchanges At Fertilization In The Egg Of The Frog Ranacameranoi, Şeref Erdoğan, Gülay Loğoğlu, Kerem Tuncay Özgünen, Tuncay Özgünen

Turkish Journal of Biology

The apparent change in the egg membrane potential at fertilization gives rise to fertilization potential (FP) . FP is the initial, transient electrical block to polyspermy as shown in most species especially those exhibiting external fertilization, and it protects the egg from a second sperm entry until the permanent, mechanical block is set up. Polyspermy is lethal in most species, and for a successful fertilization resting membrane potential (RMP) and FP of the egg have to be held in optimum ranges. Shifts in environmental pH may interfere with a successful fertilization by affecting these bioelectrical potentials. In the present study, …

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