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Genetic Control Of Programmed Cell Death In The Caenorhabditis Elegans Hermaphrodite Germline, Tina Gumienny, Eric Lambie, Erika Hartwieg, H. Robert Horvitz, Michael Hengartner Feb 1999

Genetic Control Of Programmed Cell Death In The Caenorhabditis Elegans Hermaphrodite Germline, Tina Gumienny, Eric Lambie, Erika Hartwieg, H. Robert Horvitz, Michael Hengartner

Dartmouth Scholarship

Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same apoptotic execution machinery (ced-3, ced-4 and ced-9) as the previously described 131 somatic cell deaths. However, this machinery is activated by a distinct pathway, as loss of egl-1 function, which inhibits somatic cell death, does not affect germ cell apoptosis. …

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The Multiple Roles Of Cyk1p In The Assembly And Function Of The Actomyosin Ring In Budding Yeast, Katie Shannon, Rong Li Feb 1999

The Multiple Roles Of Cyk1p In The Assembly And Function Of The Actomyosin Ring In Budding Yeast, Katie Shannon, Rong Li

Biological Sciences Faculty Research & Creative Works

The budding yeast IQGAP-like protein Cyk1p/Iqg1p localizes to the mother-bud junction during anaphase and has been shown to be required for the completion of cytokinesis. In this study, video microscopy analysis of cells expressing green fluorescent protein-tagged Cyk1p/Iqg1p demonstrates that Cyk1p/Iqg1p is a dynamic component of the contractile ring during cytokinesis. Furthermore, in the absence of Cyk1p/Iqg1p, myosin II fails to undergo the contraction-like size change at the end of mitosis. To understand the mechanistic role of Cyk1p/Iqg1p in actomyosin ring assembly and dynamics, we have investigated the role of the structural domains that Cyk1p/Iqg1p shares with IQGAPs. An amino …

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Cryptic Luminescence In The Cold-Water Fish Pathogen Vibrio Salmonicida, P. M. Fidopiastis, Henning Sørum, E. G. Ruby Feb 1999

Cryptic Luminescence In The Cold-Water Fish Pathogen Vibrio Salmonicida, P. M. Fidopiastis, Henning Sørum, E. G. Ruby

Biological Sciences

The recent discovery that the fish pathogen Vibrio salmonicida is closely related to the luminous bacteria Vibrio fischeri and Vibrio logei suggested that V. salmonicida might also be capable of bioluminescence. Interestingly, cells of V. salmonicida were found to produce light in culture, but only when exposed to either an aliphatic aldehyde and/or the major V. fischeri autoinducer N-(3-oxo-hexanoyl)-l-homoserine lactone, a transcriptional activator of the luminescence (lux) genes. An extract of spent medium of V. salmonicida that should contain any V. salmonicida acyl-homoserine lactone autoinducer, when added to V. fischeri cells, led to an induction of their …

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Genome-Wide Bioinformatic And Molecular Analysis Of Introns In Saccharomyces Cerevisiae, Marc Spingola, Leslie Grate, David Haussler, Manuel Ares Feb 1999

Genome-Wide Bioinformatic And Molecular Analysis Of Introns In Saccharomyces Cerevisiae, Marc Spingola, Leslie Grate, David Haussler, Manuel Ares

Biology Department Faculty Works

Introns have typically been discovered in an ad hoc fashion: introns are found as a gene is characterized for other reasons. As complete eukaryotic genome sequences become available, better methods for predicting RNA processing signals in raw sequence will be necessary in order to discover genes and predict their expression. Here we present a catalog of 228 yeast introns, arrived at through a combination of bioinformatic and molecular analysis. Introns annotated in the Saccharomyces Genome Database (SGD) were evaluated, questionable introns were removed after failing a test for splicing in vivo, and known introns absent from the SGD annotation were …

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Exploring Cost Constraints On Stem Elongation In Plants Using Phenotypic Manipulation, Don Cipollini, Jack C. Schultz Feb 1999

Exploring Cost Constraints On Stem Elongation In Plants Using Phenotypic Manipulation, Don Cipollini, Jack C. Schultz

Biological Sciences Faculty Publications

Negative associations between individual life‐history traits of an organism are referred to as life‐history trade‐offs (Stearns 1992; Zera et al. 1998). The existence of costly trade‐offs is thought to have favored the evolution of phenotypic plasticity as a mechanism through which organisms can account for environmental heterogeneity while modulating costs and benefits incurred by fixed allocation to competing functions (Bradshaw 1965; Stearns 1992; Sultan 1995; Dudley and Schmitt 1996; Pigliucci 1996). In plants, the ability to modify stem elongation in response to environmental cues appears to be a classic form of adaptive phenotypic plasticity (Sultan 1995; Gedroc et al. 1996). …

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Physiological And Morphological Correlates Of Presynaptic Inhibition In Primary Afferents Of The Lamprey Spinal Cord, I. V. Batueva, E. A. Tsvetkov, A. K. Sagatelyan, James T. Buchanan, N. Vesselkin, V. Adanina, E. I. Suderevskaya, J. -P Rio, J. Repérant Feb 1999

Physiological And Morphological Correlates Of Presynaptic Inhibition In Primary Afferents Of The Lamprey Spinal Cord, I. V. Batueva, E. A. Tsvetkov, A. K. Sagatelyan, James T. Buchanan, N. Vesselkin, V. Adanina, E. I. Suderevskaya, J. -P Rio, J. Repérant

Biological Sciences Faculty Research and Publications

Patch-clamp recordings in a whole-cell mode were performed on dorsal sensory cells enzymatically isolated from the spinal cord of two lamprey species, Ichthyomyzon unicuspis and Lampetra fluviatilis. The voltage-activated currents through calcium channels were analysed. GABA and the specific GABAB receptor agonist baclofen reduced the peak amplitude of inward Ba2+ current, as a robust alternate charge carrier through voltage-dependent Ca2+ channels. These effects were dose-dependent and reversible. GABAB receptor antagonists, 2-hydroxysaclofen and δ-amino-n-valeric acid, blocked the reduction of Ba2+ currents by GABA and baclofen, while bicuculline, a GABAA receptor antagonist, had no blocking …

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Functional Success Of Six Constructed Bottomland Hardwood Forests In Central And Western Kentucky, Ryan W. Mccall Jan 1999

Functional Success Of Six Constructed Bottomland Hardwood Forests In Central And Western Kentucky, Ryan W. Mccall

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Ryan W. McCall on January 25, 1999.

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Rainfall Stimulation Of Primary Production In Western Atlantic Ocean Waters: Roles Of Different Nitrogen Sources And Co-Limiting Nutrients, Hans W. Paerl, Joan D. Willey, Malia Go, Benjamin L. Peierls, James L. Pinckney, Marilyn L. Fogel Jan 1999

Rainfall Stimulation Of Primary Production In Western Atlantic Ocean Waters: Roles Of Different Nitrogen Sources And Co-Limiting Nutrients, Hans W. Paerl, Joan D. Willey, Malia Go, Benjamin L. Peierls, James L. Pinckney, Marilyn L. Fogel

Faculty Publications

Using shipboard bioassays, we examined the roles rainfall, individual and combined nutrients play in accelerating primary production in coastal, Gulf Stream and pelagic (Sargasso Sea) locations in the North Atlantic Ocean off North Carolina, USA, from 1993 to 1995. Photosynthetic CO2 fixation and net chlorophyll a (chl a) production were measured In replicated bioassays to assess individual and combined impacts of different constituents of atmospheric deposition, including natural rainfall, a synthetic rain mix, dissolved inorganic nitrogen (DIN; NH4+ ,NO3-), dissolved organic nitrogen (DON; urea),phosphorus (PO43-) and iron (as EDTA-chelated and …

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The Roles Of Island Area Per Se And Habitat Diversity In The Species-Area Relationships Of Four Lesser Antillean Faunal Groups, Robert Ricklefs, Irby Lovette Jan 1999

The Roles Of Island Area Per Se And Habitat Diversity In The Species-Area Relationships Of Four Lesser Antillean Faunal Groups, Robert Ricklefs, Irby Lovette

Biology Department Faculty Works

1. We analysed the relationships between species richness, island area, and habitat diversity for birds, bats, butterflies, and reptiles and amphibians on 19 islands in the Lesser Antilles. Habitat diversity was quantified by Simpson's index based on the total areas of five vegetation types on each island. Island area varied over two orders of magnitude (13–1510 km2) and habitat diversity varied between 1 and 3·7 equivalents of equally abundant habitat types.2. Because the Lesser Antilles consist of an inner arc of high, volcanic islands and an outer arc of low‐lying islands formed of uplifted marine sediments, correlations between area and …

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Osteological Analysis Of The Killifish Genus Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro, Rafael O. De Sá Jan 1999

Osteological Analysis Of The Killifish Genus Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro, Rafael O. De Sá

Biology Faculty Publications

Relationships among the species of the annual fish Cynolebias are unclear. An analysis of the variation and utility of osteological characters for phylogenetic analysis was done using cleared and double-stained specimens representing 21 species of Cynolebias. This analysis showed that some of the characters previously used to diagnose this genus and some of the species are polymorphic. Osteologically, Cynolebias can be diagnosed by the following synapomorphies: (1) triangular-shaped parietal, (2) vomer positioned ventral to the parasphenoid, (3) long ventral process of the dentary, (4) teeth on fourth ceratobranchial, and (5) teeth on first epibranchial. In addition, characters that help …

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Production Of Monoclonal Antibodies Specific Forprogesterone, Fatma Şahi̇ngöz Yücel, Beyazit Çirakoğlu Jan 1999

Production Of Monoclonal Antibodies Specific Forprogesterone, Fatma Şahi̇ngöz Yücel, Beyazit Çirakoğlu

Turkish Journal of Biology

Progesterone levels in milk and serum are indicators of pregnancy in cattle. The progesterone level reaches a peak on the 21 st and 22 nd days of pregnancy. Monoclonal antibodies specific to progesterone could be used for the immunodetection of milk and serum progesterone levels. We report here the development of hybrid cells prdoducing monoclonal antibodies specific for progesterone using hybridoma technology. Hybridoma cells secreting monoclonal antibodies against progesterone (MAM 2H11, MAM 6G6) were developed by fusion of the spleen cells of an immunized BALB/c mouse with FO (ATCC CRL 1646) mouse myeloma cells. These monoclonal antibodies were characterized for …

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Ultrastructural Observations On Connectioncomplexes Between The Mural Trophoblast Cells Ofblastocyst In The Rat, Ramazan Demi̇r, İsmai̇l Üstünel, Necdet Demi̇r Jan 1999

Ultrastructural Observations On Connectioncomplexes Between The Mural Trophoblast Cells Ofblastocyst In The Rat, Ramazan Demi̇r, İsmai̇l Üstünel, Necdet Demi̇r

Turkish Journal of Biology

It is generally accepted that implantation morphologically consists of the establishment of a contact between the blastocyst and the uterine tissues. During this contact and interaction process, many physiological, biochemical and ultrastructural factors are involved. The aim of this study was to describe the ultrastructure of connection complexes between mural trophoblast cells in the blastocystic ring in the rat. Implantation sites obtained from rats on day 5 of pregnancy were studied ultrastructurally. Connected complexes were observed between mural trophoblast cells in different three types: a) dense long line connection; b) desmosome-like sturctures; c) regular suture-like interdigitation resembling parallel railings. According …

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The Accumulation And Histological Effects Of Theorganometallic Fungicide Propineb On The Organsof Fetuses And Female Rats During Pregnancy, Kemal Güven, Engi̇n Deveci̇, Davi̇d De Pomerai Jan 1999

The Accumulation And Histological Effects Of Theorganometallic Fungicide Propineb On The Organsof Fetuses And Female Rats During Pregnancy, Kemal Güven, Engi̇n Deveci̇, Davi̇d De Pomerai

Turkish Journal of Biology

Dithiocarbamate propineb is an organometal fungicide, which is widely used for the control of diseases in plants. Female Wistar rats were exposed orally to propineb concentrations of 200 and 400 ppm, from the 6th day of gestation up to birth. At 400 ppm, propineb showed a variety of macroscopic (e.g. ptosis and paralysis) and microscopic symptoms in the organs of both fetuses and female rats. We found that the body weights of both one-day old litters and their propineb-treated mothers were lower than those of the controls. Histological examination of the livers and kidneys of the fetuses and propineb-treated pregnant …

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Lack Of Minority Advantage In Drosophilamelanogaster Mutants, Şükran Çakir, Aykut Kence Jan 1999

Lack Of Minority Advantage In Drosophilamelanogaster Mutants, Şükran Çakir, Aykut Kence

Turkish Journal of Biology

The objective of this study was to test the generality of frequency-dependent fitness in the mating behavior of Drosophila, called the minority effect and to investigate the effect of artificial olfactory cues and marking the flies by wing cillipng on the frequency-dependent mate choice. In the mating experiments using wild type (oregon) and mutant (white-eyed, sepia, ebony) strains of Drosophila melanogaster, the mating success of mutant males did not increase as their frequency decreased. In addition, the olfactory cue hypothesis was not supported by the results of the experiments with artificial scent. The results of this study did not support …

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Purification And Characterization Of Cysteine-43mutant Citrate Synthase From Thermoplasmaacidophilum, İpek Erduran, Semra Kocabiyik Jan 1999

Purification And Characterization Of Cysteine-43mutant Citrate Synthase From Thermoplasmaacidophilum, İpek Erduran, Semra Kocabiyik

Turkish Journal of Biology

Two cysteine residues were introduced to selected positions (Serine-309 and Serine-43) of the Thermoplasma acidophilum citrate synthase. Serine-309 Cysteine mutation drastically reduced the activity, as well as the thermostabiity of the enzyme. Although Serine-43 Cysteine mutation reduced the enzyme activity, it did not have any effect on the thermostability. Both wild-type and cysteine-43 mutant Thermoplasma citrate synthase enzymes were purified to homogenity using affinity chromatography on Matrex Gel Red A. The cysteine-43 mutant Thermoplasma citrate synthase was strikingy similar to the wild-type recombinant citrate synthase in its molecular size, substrate and co-factor specificities, pH profile and thermal resistance. The decrease …

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Determination Of The Presence Of Crpgenes Instaphylococcus Aureus, Staphylococcus Epidermidis,Lactobacillus Delbrueckii Andcorynebacterium Verasuş, Ali̇ Osman Beldüz, Zi̇hni̇ Demi̇rbağ, Sabri̇ye Dülger, Ali̇ Osman Kiliç Jan 1999

Determination Of The Presence Of Crpgenes Instaphylococcus Aureus, Staphylococcus Epidermidis,Lactobacillus Delbrueckii Andcorynebacterium Verasuş, Ali̇ Osman Beldüz, Zi̇hni̇ Demi̇rbağ, Sabri̇ye Dülger, Ali̇ Osman Kiliç

Turkish Journal of Biology

Polymerase chain reaction (PCR) was employed to detect the presence of cyclic AMP receptor protein (CPR) in a number of diverse organisms. In PCR, two primers specific to the crp gene of Escherichia coli were used. Staphylococcus aureus, Staphylococcus epidermidis, Lactobacillus delbrueckii and Corynebacterium veraSuş all showed the same size of PCR frağments (708 bp) and same restriction frağment length polymorphizm (RFLP).

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Properties Of The Rhodopseudomonas Palustrisstrains Isolated From An Alkaline Lake In Turkey, Gönül Çeti̇nkaya Dönmez, Ayten Öztürk, Lütfü Çakmakçi Jan 1999

Properties Of The Rhodopseudomonas Palustrisstrains Isolated From An Alkaline Lake In Turkey, Gönül Çeti̇nkaya Dönmez, Ayten Öztürk, Lütfü Çakmakçi

Turkish Journal of Biology

31 photoheterotrophic bacteria were isolated from Lake Aksehir sediment. Identification of the strains was based on morphological properties, motility and pigment composition, and also physiological properties such as carbon utilization and ability to respire anaerobically and aerobically in the dark. All strains were identified as Rhodopseudomonas palustris, but some strains were distinct from R. palustris with regard to vitamin requirement, malate utilization and aerobic growth in the dark. Until now, R. palustris had not been reported from an alkaline lake, and the strains growing alkaline pH (9) could be new strains of R. palustris.

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Isolation And Abundance Of Unicellularcyanobacteria From Mosquito Development Sites, Gönül Çeti̇nkaya Dönmez, Ayşe Elmaci, Olcay Obali, Ayten Öztürk, Lütfü Çakmakçi Jan 1999

Isolation And Abundance Of Unicellularcyanobacteria From Mosquito Development Sites, Gönül Çeti̇nkaya Dönmez, Ayşe Elmaci, Olcay Obali, Ayten Öztürk, Lütfü Çakmakçi

Turkish Journal of Biology

The genus composition of cyanobacteria (particularly Chroococcus sp.) and their abundance in mosquito breeding sites at Lake Mogan (Ankara, Turkey) increased from August to September. Six unicellular cyanobacteria that had different morphological properties were isolated and succesfully cultivated. According to the mode of division, these six strain were classified as the represantatives of subgroup 1 (order Choroococcales). One of the isolates was identified as Synechococcus sp. and one as Gloeocapsa sp., and four were identified as Synechocystic sp. One of the four Synechocystis spp. was shown to be capable of heterotrophic growth.

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Determination Of Salt Tolerance In Some Grapevinecultivars ( Vitis Vinifera L.) Under In Vitro Conditions, Nuray Si̇vri̇tepe, Ati̇lla Eri̇ş Jan 1999

Determination Of Salt Tolerance In Some Grapevinecultivars ( Vitis Vinifera L.) Under In Vitro Conditions, Nuray Si̇vri̇tepe, Ati̇lla Eri̇ş

Turkish Journal of Biology

Salinity tests were conducted on Çavus, Müsküle and Sultani Çekirdeksiz grapevine cultivars under in vitro conditions. Plant materials used in the salinity test were propagated using the axillary bud culture method. Single-node shoots were subjected to five different NaCl concentrations (0.00,0.25, 0.50, 0.75 and 1.00%) in MS+5 M BA medium for two periods (4 and 8 weeks). Proliferation, growth, total chlorophyll content and viability of explants decreased due to the increase in NaCl concentration and length of treatment period. Moreover, it was determined that salt treatment caused necroses in explants and the severity of this injury varied depending on the …

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Toxicity Of Zinc, Copper And Lead To Idotea Baltica(Crustacea, Isopoda), Levent Bat, Murat Sezgi̇n, Ayşe Gündoğdu, Mehmet Çulha Jan 1999

Toxicity Of Zinc, Copper And Lead To Idotea Baltica(Crustacea, Isopoda), Levent Bat, Murat Sezgi̇n, Ayşe Gündoğdu, Mehmet Çulha

Turkish Journal of Biology

The acute toxicity of zinc, copper and lead to the marine invertebrate Idotea baltica (Crustacea, Isopoda) was evaluated by static bioassays, calculating the LT 50 (lethality time for 50%) for males and females. Survival time decreased with increasing concentrations of zinc, copper and lead. Zinc was more toxic to Idotea than copper and lead. Lead was the least toxic of the metals tested.

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Salinity Resistance Of Certain Rice ( Oryza Sativa L.)Cultivars, Mehmet Alpaslan, Aydin Güneş, Süleyman Taban Jan 1999

Salinity Resistance Of Certain Rice ( Oryza Sativa L.)Cultivars, Mehmet Alpaslan, Aydin Güneş, Süleyman Taban

Turkish Journal of Biology

A greenhouse experiment was carried out to evaluate the response of six rice ( Oryza sativa L.) cultivars (Ribe, Tri-445, Serhat 92, Kros 424, Baldo and Rocca) to NaCI salinity. While salinity inhibited the growth of all six cultivars, Baldo, Ribe, Rocca and Kros-424 were less affected than the other cultivars. Salt treatment increased Na and CI content of the plants, while it decreased K content. In general, the proline content and stomatal resistance of the cultivars were increased by salt treatment.

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Biodegradation Of Homocyclic And Heterocyclicaromatic Compounds Byrhodopseudomonas Palustris Strains, Gönül Çeti̇nkaya Dönmez, Ayten Öztürk Jan 1999

Biodegradation Of Homocyclic And Heterocyclicaromatic Compounds Byrhodopseudomonas Palustris Strains, Gönül Çeti̇nkaya Dönmez, Ayten Öztürk

Turkish Journal of Biology

Six strains were isolated from Lake Aksehir (Konya-Turkey) and identified as Rhodopseudomonas palustris on the basis of physiological and morphological characteristics. The strains grew phototrophically on a variety of aromatic compounds (under illuminated anaerobic conditions), namely, benzoate, hippurate, benzyl alcohol, 2-amino benzoic acid, phloroglucinol, phenylacetic acid, catechol, pyridine and pyrazoline. Biodegradation of 2-amino benzoate, phloroglucinol, catechol, pyridine and pyrazolin by Rhodopseudomonas palustrisstrains have not been reported in the literature.

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Acute Lethal Toxicity And Accumulation Of Copper Ingammarus Pulex (L.) (Amphipoda), Kemal Güven, Cengi̇zhan Özbay, Erhan Ünlü, Ali̇ Satar Jan 1999

Acute Lethal Toxicity And Accumulation Of Copper Ingammarus Pulex (L.) (Amphipoda), Kemal Güven, Cengi̇zhan Özbay, Erhan Ünlü, Ali̇ Satar

Turkish Journal of Biology

Gammarus pulex (L.) collected from clean sites around Kabakli pond (Diyarbakır) was acclimatized at 15°C for 10 days. The individuals were placed in 1lt. vessels and exposed to Cu ++ concentrations of 0.05, 0.08, 0.10, 0.15, 0.20, 0.30 and 0.50 ppm to determine both 24, 48, 72 and 96 h LC50 values and Cu ++ accumulation over 96h. LC 50 values at 24, 48, 72 and 96 h were calculated to be 0.2, 0.17, 0.12 and 0.1 ppm, respectively. Acute copper accumulation in gammarids exposed to various copper concentrations over 96 h was determined using an atomic absorption spectrophotometer. An …

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Contributions To The Pollen Morphology Of Thefamily Compositae, Anjum Perveen Jan 1999

Contributions To The Pollen Morphology Of Thefamily Compositae, Anjum Perveen

Turkish Journal of Biology

The pollen morphology of 24 species of Compositae belonging to 18 genera was examined by light and scanning microscopy. The present data confirms the eurypalynous nature of the family. Delimitation of the genera on the basis of pollen characters is less marked. Pollen grains usually radially symmetrical, isopolar rarely apolar; tricolporate, often porate. Shape commonly oblate-spheroidal to prolate-spheroidal, with some suboblate to subprolate types. Tectum echinate to echinolophate, often non-echinate. Tectum in-between the spines or spinules is sub-psilate, or perforated to striate. On the basis of the exine pattern, 4 distinct pollen types are recognized viz., Pollen type-I: Dicoma tomentosa, …

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Acute Toxicity Of Zinc, Copper And Lead To Threespecies Of Marine Organisms From The Sinoppeninsula, Black Sea, Levent Bat, Ayşe Gündoğdu, Murat Sezgi̇n, Mehmet Çulha, Gamze Gönlügür, Mehmet Akbulut Jan 1999

Acute Toxicity Of Zinc, Copper And Lead To Threespecies Of Marine Organisms From The Sinoppeninsula, Black Sea, Levent Bat, Ayşe Gündoğdu, Murat Sezgi̇n, Mehmet Çulha, Gamze Gönlügür, Mehmet Akbulut

Turkish Journal of Biology

Acute toxicity tests were performed on Echinogammars olivii (Amphipoda), Sphaeroma serratum (Isopoda) and Palaemon elegans (Decapoda), from the Sinop Peninsula in the Black Sea. 96- h LC 50 values were estimated for copper, zinc and lead in these species using the static bioassay method. The LC 50 values of Cu for E. olivii, S. serratum and P. elegans were 0.25, 1.98 and 2.52 mg/l, respectively. The LC 50 values of Zn for E. olivii , S. serratum and P. elegans were 1.30, 6.12 and 12.3 mg/l, respectively. The LC 50 values of Pb for E. olivii, S. serratum and P. …

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The Inhibition Of The Genotoxic Effects Ofenvironmental Pollutants And The Aging Processesby Plant Antimutagens, Urkhan Alekperov, Rena Gulieva, Ramiz Alekperov Jan 1999

The Inhibition Of The Genotoxic Effects Ofenvironmental Pollutants And The Aging Processesby Plant Antimutagens, Urkhan Alekperov, Rena Gulieva, Ramiz Alekperov

Turkish Journal of Biology

We investigated the effects of bioactive compounds obtained from fruits of Diospyros kaki L., Cydonia oblonga Mill. and roots of Glycyrrhiza glabra L., as well as their action in a complex mixture on the mutability in marrow cell chromosomes induced by genotoxicants (X-rays, N-Methyl-N-Nitrosurea, Cyclophosphamide) and aging. The plant products tested separately and in a complex mixture showed an ability to decrease the frequency of induced mutations in experimental animals. Antimutagenic properties of the complex mixture turned out to be considerably higher than its components separately. More antimutagenic activity of the mixture was revealed when mutagenesis was the result of …

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On The Kinetics Of Human Erythrocyte Glutathionedisulfide Reductase: Does The Enzyme Really Play'ping-Pong'?, İ. Hamdi̇ Öğüş, Nazmi̇ Özer Jan 1999

On The Kinetics Of Human Erythrocyte Glutathionedisulfide Reductase: Does The Enzyme Really Play'ping-Pong'?, İ. Hamdi̇ Öğüş, Nazmi̇ Özer

Turkish Journal of Biology

: Human erythrocyte glutathione disulfide reductase studied at 37°C in 100 mM potassium phosphate buffer, pH 7.4, is subject to partial inhibition by GSSG at low [NADPH]. Saturation by NADPH is hyperbolic at low [GSSG] and becomes increasingly sigmoidal at high [GSSG]. NADP+ is a competitive inhibitor with respect to NADPH at 20-1000 µM GSSG and an uncompetitive inhibitor with respect to GSSG at 33-120 µM NADPH. Studied under special conditions (10 µM NADPH and 1000 µM GSSG), NADP+ exhibits a two-fold effect, inhibition being preceded by activation in the 0- 50 µM effector concentration range. The data are consistent …

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Variation In The Nucleolus Organizer Regions (Nors)In Two Mole Rat Species ( Spalax Leucodon Andspalax Ehrenbergi), Mehmet Doğan Gülkaç, İlknur Şendoğdu Küçükdumlu Jan 1999

Variation In The Nucleolus Organizer Regions (Nors)In Two Mole Rat Species ( Spalax Leucodon Andspalax Ehrenbergi), Mehmet Doğan Gülkaç, İlknur Şendoğdu Küçükdumlu

Turkish Journal of Biology

In this investigation, patterns of variation in the nucleolus organizer regions (NORs) in the chromosomes of Spalax leucodon and Spalax ehrenbergi were studied. The chromosomal location of the Ag-NORs was determined in two mole rat species. S. leucodon has 3 pairs of nucleolar chromosomes, but S. ehrenbergi has only 2 pairs of nucleolar chromosomes in their whole chromosome sets. In both mole rat species, the chromosomal locations of Ag-NORs were determined to be on the terminal of the short arms of the subtelocentrics. The possibilty of Robertsonian translocation and the loss of paracentric NORs in S. ehrenbergi were discussed from …

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Cytosolic Ca 2+ Levels In Co25 Myoblast Cells Bearinga Human N-Ras Oncogene After Stimulation By Thap-Sigarginand Growth Factors, Hülya Zeyti̇noğlu, Ian Gibson Jan 1999

Cytosolic Ca 2+ Levels In Co25 Myoblast Cells Bearinga Human N-Ras Oncogene After Stimulation By Thap-Sigarginand Growth Factors, Hülya Zeyti̇noğlu, Ian Gibson

Turkish Journal of Biology

The levels of intracellular calcium [Ca 2+ ]i were examined in CO25 myoblast cells bearing a mutated human N-ras oncogene, after stimulation by thapsigargin (ThG), bombesin and epidermal growth factor (EGF). Thapsigargin induced a [Ca 2+ ]i rise mostly from intracellular calcium pools, and a small Ca 2+ entry into cytoplasm via the plasma membrane channel. In both ras-induced and differentiated CO25 cells, [Ca 2+ ]i increase showed a similar pattern of events after addition of ThG. The addition of EGF and bombesin to both ras-induced and differentiated cells did not induce Ca 2+ mobilization, suggesting that the cells may …

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Anthranilate Synthetase From Escherichia Coli Sjhi:Purification And Some Properties, Münevver Arisoy Jan 1999

Anthranilate Synthetase From Escherichia Coli Sjhi:Purification And Some Properties, Münevver Arisoy

Turkish Journal of Biology

A procedure employed in the purification of anthranilate synhetase of Escherichia coli SJHI is described. The purified anthranilate synthetase appeared to be homogeneous when examined with poliacrylamide gel electrophoresis. Phenly-sepharose CL-4B and Blue dye sepharose were used for purification. A positive correlation was found between purification and ammonium sulfate especially using concentrations greater than 10%. A positive effect 2-Mercapto-ethanol on the enzyme stability was also determined.

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