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2001

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Articles 271 - 300 of 303

Full-Text Articles in Biology

Comparison Of 22 Taurus Cedar (Cedrus Libani A. Rich.) Origins By Seedling Morphological Distance, Zeki̇ Yahyaoğlu, Ali̇ Demi̇rci̇, Nebi̇ Bi̇li̇r, Musa Genç Jan 2001

Comparison Of 22 Taurus Cedar (Cedrus Libani A. Rich.) Origins By Seedling Morphological Distance, Zeki̇ Yahyaoğlu, Ali̇ Demi̇rci̇, Nebi̇ Bi̇li̇r, Musa Genç

Turkish Journal of Biology

In this study, seeds were collected from 22 seed stands of Taurus cedar (Cedrus libani A. Rich.), and these seeds were sown at the Black Sea Technical University Nursery in 1995. The main morphological characteristics of 2+0 year old seedlings were measured in 1997. Values of seedling morphological distance were calculated using the Penrose formula to compare the origins in terms of morphological characteristics. According to the Penrose formula, when the values of morphological distance (P_{ij}) approach zero, the similarity between origins increases. Consequently, the most similar origins were Mugla-Arpacik and Isparta-Belcegiz2 (P_{18,22}=0.040), while the most different origins were Mersin-Aslankoy …

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Effects Of High Dietary Protein And High Energy Density On Gastric Evacuation And Return Of Appetite In The Rainbow Trout, Oncorhynchus Mykiss, Ahmet Adem Teki̇nay, Yusuf Güner Jan 2001

Effects Of High Dietary Protein And High Energy Density On Gastric Evacuation And Return Of Appetite In The Rainbow Trout, Oncorhynchus Mykiss, Ahmet Adem Teki̇nay, Yusuf Güner

Turkish Journal of Biology

Rainbow trout (Oncorhynchus mykiss) were fed diets containing three different concentrations of crude protein (56.3%, 51.7% and 45.8%) and digestible energy (21.3, 20.3 and 18.8 MJ/kg), and the effects of dietary protein and energy level on gastric evacuation and return of appetite times were investigated. Gastric evacuation determinations were achieved by slaughtering 8 fish every 6 hours until no residue was found in the cardiac stomach of fish. Return of appetite experiments were conducted by re-feeding groups of trout every 4 or 6 hours following the first feeding. The data obtained from each process was modelled by regression analysis and …

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Determination Of The Dna And Amino Acid Sequences Of The Lactate Dehydrogenase Gene From Plasmodium Falciparum Strains K1 And Pf Fcbr: A Route To The Design Of New Antimalarials, Di̇lek Turgut Balik, J. John Holbrook Jan 2001

Determination Of The Dna And Amino Acid Sequences Of The Lactate Dehydrogenase Gene From Plasmodium Falciparum Strains K1 And Pf Fcbr: A Route To The Design Of New Antimalarials, Di̇lek Turgut Balik, J. John Holbrook

Turkish Journal of Biology

This paper describes cloning of the gene coding for the lactate dehydrogenase (LDH) gene from the two different strains of Plasmodium falciparum, K1 and PF FCBR. The DNA sequences of LDH genes of these two strains were found to be identical. Amino acid sequence alignment of LDH from P. falciparum strains K1 and PF FCBR (PfLDH) to some other known LDH sequences showed that PfLDH has 29% residue identities with Bacillus stearothermophilus (BsLDH) and 29%, 31%, 33% with dogfish, man-M_4, and pig-M_4 LDHs, respectively. It was also shown that PfLDH has insertions and single amino acid deletions. Two deletions are …

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The Role Of P13-Kinase On Melanoma Cell Adhesion And Migration, Zerri̇n Seller, Ian R. Hart Jan 2001

The Role Of P13-Kinase On Melanoma Cell Adhesion And Migration, Zerri̇n Seller, Ian R. Hart

Turkish Journal of Biology

Integrins are responsible for anchoring cells to the extracellular matrix and also can initiate intracellular signal pathways. The interaction between integrins and the extracellular matrix results in activation of PKC, PTKs, p21Ras, MAPK and PI3-kinase. The \alpha4\beta1 integrins are expressed mainly on haematopoietic cells and also appear on several tumour types. The adhesion of \alpha4\beta1 to VCAM-1 is an essential step for lymphocyte extravasation during the inflammatory response. Furthermore, the interaction of \alpha4\beta1, expressed on tumour cells, with VCAM-1, might have a role in tumour cell extravasation. We examined the role of PI3-kinase activation in \alpha4\beta1-mediated melanoma cell adhesion and …

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Production Of Ethanol From Beet Molasses By Ca-Alginate Immobilized Yeast Cells In A Packed-Bed Bioreactor, Yekta Göksungur, Neşe Zorlu Jan 2001

Production Of Ethanol From Beet Molasses By Ca-Alginate Immobilized Yeast Cells In A Packed-Bed Bioreactor, Yekta Göksungur, Neşe Zorlu

Turkish Journal of Biology

The continuous production of ethanol from beet molasses by Ca-alginate immobilized Saccharomyces cerevisiae in a packed-bed bioreactor was investigated. The temperature was maintained at 30°C and the dilution rate was 0.22 h^{-1}. Maximum ethanol (4.62%), theoretical yield (82.9%) and volumetric productivity (10.16 gl^{-1}h^{-1}) were obtained from the beet molasses medium containing 10.90% total sugar with 2.0-2.4 mm diameter beads prepared from 2% (w/v) sodium alginate solution. At higher substrate concentrations, substrate was recirculated through the packed-bed bioreactor to increase yields and to decrease residual sugar content. The bioreactor system was operated at a constant dilution rate of 0.22 h^{-1} for …

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Effects Of Cd^{2+}, Zn^{2+}, Li^+ And Al^{3+} On The Fertilization-Induced Membrane Potential Changes In The Egg Of The Frog Rana Cameranoi, Şeref Erdoğan, Gülay Loğoğlu, Kerem Tuncay Özgünen, Tuncay Özgünen Jan 2001

Effects Of Cd^{2+}, Zn^{2+}, Li^+ And Al^{3+} On The Fertilization-Induced Membrane Potential Changes In The Egg Of The Frog Rana Cameranoi, 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 risk is increased when this effective electrical block cannot reach a certain peak value or when it is of short duration. On the other hand, metal accumulation in the external environment is potentially toxic to living beings, and we aimed in the present study to evaluate …

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Assessment Of Polymorphic Aflp Markers In Triticum Durum And Aegilops Sp., Aytül İnci̇rli̇, Hati̇ce Bi̇lgi̇ç, Mahi̇nur S. Akkaya Jan 2001

Assessment Of Polymorphic Aflp Markers In Triticum Durum And Aegilops Sp., Aytül İnci̇rli̇, Hati̇ce Bi̇lgi̇ç, Mahi̇nur S. Akkaya

Turkish Journal of Biology

Compared to other Polymerase Chain Reaction (PCR) based molecular markers, the Amplified Fragment Length Polymorphism (AFLP) marker system probably requires more technical expertise for the sequential enzymatic reaction steps. In addition, the reproducibility of the AFLP marker patterns is much more dependent on the quality and the purity of the DNA samples to be processed. The present study describes the optimization of reaction conditions and determination of the most polymorphic selective amplification primer sets in a comparison of winter and spring type Turkish durum wheat varieties. AFLP products resulted in about 100 bands, and the number of polymorphic AFLP loci …

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Effects Of Photoperiod And Melatonin Infusions On Body Weight In Pinealectomized Juvenile Siberian Hamsters (Phodopus Sungorus), Bülent Gündüz, Alper Karakaş Jan 2001

Effects Of Photoperiod And Melatonin Infusions On Body Weight In Pinealectomized Juvenile Siberian Hamsters (Phodopus Sungorus), Bülent Gündüz, Alper Karakaş

Turkish Journal of Biology

We examined the effects of daily melatonin (Mel) infusions in pinealectomized prepubertal male Siberian hamsters in three different conditions. In one study we investigated the body weight maturation response to one hour daily infusions of 10 ng, 25 ng, or 50 ng of Mel in pinealectomized hamsters. Animals received, at day 15 of life, programmed subcutaneous infusions of Mel or vehicle at one of five time points (1900-2000, 2000-2100, 2100-2200, 2400-0100, and 0300-0400 hours) for 30 days. In long-day-born (16L) animals, Mel infusion right after lights off (2000-2100 hours) significantly inhibited body growth; this dose was ineffective at other times. …

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The Effect Of Paraquat On The Activity Of Some Enzymes In Different Tissues Of Mice (Mus Musculus - Swiss Albino), Egemen Dere, Fi̇kri̇ye Polat Jan 2001

The Effect Of Paraquat On The Activity Of Some Enzymes In Different Tissues Of Mice (Mus Musculus - Swiss Albino), Egemen Dere, Fi̇kri̇ye Polat

Turkish Journal of Biology

The effects of the LD_{30} (20 mg.kg^{-1}) dose of paraquat, a herbicide, were investigated on creatine kinase (CK), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), lactate dehydrogenase (LDH) and gamma glutamyl transferase (GGT) activities in the liver, kidney and lung of mice after 2, 4, 8, 16, 32, 64 and 72 hours. After paraquat was given intraperitoneally to Mus musculus Swiss albino mice, the control groups were injected with physiological saline. The results were evaluated using the autoanalyzer as U/L. Even though significant increases in the liver tissue LDH and GGT, kidney tissue CK and lung tissue CK and …

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The Analysis Of Rhodococcus Ruber In Different Growth Conditions Using Pyrolysis Mass Spectrometry (Pyms), Ergi̇n Kari̇ptaş, Kami̇l Işik, Nevzat Şahi̇n, Reşi̇t Özkanca, Alan C. Ward Jan 2001

The Analysis Of Rhodococcus Ruber In Different Growth Conditions Using Pyrolysis Mass Spectrometry (Pyms), Ergi̇n Kari̇ptaş, Kami̇l Işik, Nevzat Şahi̇n, Reşi̇t Özkanca, Alan C. Ward

Turkish Journal of Biology

Batch grown cultures of Rhodococcus ruber from different growth phases and continuous grown cultures from carbon, phosphate and magnesium limitation were analysed by pyrolyis mass spectrometry (PyMS). Batch grown cells showed significantly different pyrograms and the stationary phase cells could be clearly distinguished from exponential phase cells. Mass pyrograms of carbon, phosphate and magnesium limited cells were clearly different and, for carbon and phosphate limitation, clear trends were seen with different dilution rates. Changes in pH and temperature had no systematic effect on mass pyrograms.

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Antiviral And Cytotoxic Activities Of Extracts From The Cell Cultures And Respective Parts Of Some Turkish Medicinal Plants, Atalay Sökmen Jan 2001

Antiviral And Cytotoxic Activities Of Extracts From The Cell Cultures And Respective Parts Of Some Turkish Medicinal Plants, Atalay Sökmen

Turkish Journal of Biology

Extracts from respective parts and cell cultures of some Turkish medicinal plants have been assessed for their antiviral and cytotoxic properties. None of the extracts tested showed notable activity against herpes simplex viruses (HSV-I and II), but a slight antiretroviral activity against HIV-I was determined in an extract from Hypericum capitatum cell cultures. On the other hand, according to cytotoxic activity test results against brine shrimp (Artemia salina), an activity level of LD_{50} at 34.9 µg/ml was found on the extracts of Ecbalium elaterium cell cultures.

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Oxylipin Pathway In The Biosynthesis Of Fresh Tomato Volatiles, Emi̇n Yilmaz Jan 2001

Oxylipin Pathway In The Biosynthesis Of Fresh Tomato Volatiles, Emi̇n Yilmaz

Turkish Journal of Biology

Fresh tomato volatiles are formed in intact fruit during ripening and upon tissue disruption. There are different pathways involved in the biosynthesis of these volatiles. The oxylipin pathway uses free unsaturated fatty acids with the sequential action of lipoxygenase, hydroperoxide lyase and alcohol dehydrogenase to produce volatile aldehyde and alcohol compounds. Oxylipin volatiles are the most important components in fresh tomato aroma. In order to genetically improve the quality of tomato aroma, the biochemistry of aroma synthesis must be studied thoroughly. This review examines current knowledge of the subject and opens new areas for further investigation.

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The Cytogenetic Effects Of Sodium Metabisulfite, A Food Preservative In Root Tip Cells Of Allium Cepa L., Eyyüp Rencüzoğullari, Ahmet Kayraldiz, Hasan Basri̇ İla, Tonguz Çakmak, Mehmet Topaktaş Jan 2001

The Cytogenetic Effects Of Sodium Metabisulfite, A Food Preservative In Root Tip Cells Of Allium Cepa L., Eyyüp Rencüzoğullari, Ahmet Kayraldiz, Hasan Basri̇ İla, Tonguz Çakmak, Mehmet Topaktaş

Turkish Journal of Biology

The effects of sodium metabisulfite (SMB) on mitosis were investigated in Allium cepa L. The roots of A. cepa were treated with SMB concentrations of 7.5 mg/lt, 15 mg/lt and 30 mg/lt for 10- and 20-hour treatment periods. SMB significantly decreased the mitotic index (MI) at all concentrations and treatment periods. While the decreasing of the MI was dose-dependent at 10 hours treatment time, SMB increased the mitotic abnormalities dose dependently.

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Production Of Single-Cell Protein From Ram Horn Hydrolysate, Esabi̇ Başaran Kurbanoğlu Jan 2001

Production Of Single-Cell Protein From Ram Horn Hydrolysate, Esabi̇ Başaran Kurbanoğlu

Turkish Journal of Biology

Candida utilis NRRL Y-900 was grown on horn hydrolysate for single-cell protein production. First, ram horns obtained from slaughterhouse in Erzurum were hydrolyzed by physical and chemical methods and crude horn hydrolysate (CHH) was obtained. The contents of protein, nitrogen, ash, some minerals, total sugars and amino acids of CHH were determined and it was seen that it has sufficient organic and inorganic materials to allow its use as a substrate source in the production of single-cell protein. The CHH was enriched by addition of yeast extract, glucose and KH_2PO_4. The effects of different CHH concentrations (1, 2, 3, 4, …

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Molecular Characterization Of The Gene Encoding For The Salivaricin B Activity And Its Flanking Sequences, Osman Çataloluk Jan 2001

Molecular Characterization Of The Gene Encoding For The Salivaricin B Activity And Its Flanking Sequences, Osman Çataloluk

Turkish Journal of Biology

Lactic acid bacteria (LAB) produce many different antimicrobial proteins, some of which have potential in food preservation. The molecular analysis of bacteriocins has gained much attention and has advanced rapidly in recent years, and it became routine to analyze the way in which bacteriocins are expressed and translocated. Since they are associated with foods of plant and animal origins, the shared interest is that they can be utilized as a vector to deliver the active constituents at the target in the gastrointestinal tract after digestion and be used in therapy. In this respect, the molecular pattern of the expression and …

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In Situ Localization Of Germin Gene Expression During Auxin Induced Callus Formation, Mahmut Çalişkan Jan 2001

In Situ Localization Of Germin Gene Expression During Auxin Induced Callus Formation, Mahmut Çalişkan

Turkish Journal of Biology

Wheat embryogenic callus was induced by treating immature wheat embryos with 2,4-D. Digoxigenin-labeled germin sense and anti-sense RNA probes were prepared by in vitro transcription. By using these probes it was revealed that there was a striking induction of germin gene expression prior to visible callus formation. Although no germin gene expression was localized on the sections of immature embryos which were not incubated in callus induction medium, following 4 hours incubation in callus induction medium, germin mRNA was localized on the sections of immature embryos. Germin gene expression more conspicuous and widespread on the sections which were incubated for …

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Restriction Fragment Length Polymorphism Analysis (Rflp) Of Some Streptomyces Strains From Soil, Ekrem Atalan Jan 2001

Restriction Fragment Length Polymorphism Analysis (Rflp) Of Some Streptomyces Strains From Soil, Ekrem Atalan

Turkish Journal of Biology

To separate the unknown Streptomyces strains isolated from soil samples, the interspacer regions of 16S-23S rDNA of 14 isolates were amplified with PCR (polymerase chain reaction) and digested with three restriction endonucleases, namely, Bsp143I, HaeIII and MnlI. The restriction patterns were used for RFLP (restriction fragment length polymorphism) analysis. A dendrogram were constructed using the unweighed pair group method using arithmetic averages algorithm (UPGMA) after analysis restriction patterns. Five RFLP groups were obtained anone test strain was left as a single member group. RFLP profile indicated that unknown strains could be identified with data based on the interspacer region of …

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Pulsed-Field Gel Electrophoresis (Pfge) Technique And Its Use In Molecular Biology, Esi̇n Basim, Hüseyi̇n Basim Jan 2001

Pulsed-Field Gel Electrophoresis (Pfge) Technique And Its Use In Molecular Biology, Esi̇n Basim, Hüseyi̇n Basim

Turkish Journal of Biology

In recent years, the use of pulsed-field gel electrophoresis (PFGE) in the molecular biology area has been subject to much research. PFGE is a powerful tool for characterizing various strains at the DNA level, obtaining relevant information on genome size and constructing the physical and genetic map of the chromosome of bacteria that are poorly understood at the genetic level as well as in separating chromosomes in microorganisms, and in the long-range mapping of mammalian genes. PFGE also has advantage of examining the elongated and oriented configuration of large DNA molecules in agarose gels at finite field strengths. In this …

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Viral Control Of The European Pine Sawfly, Neodiprion Sertifer (Geoffroy) In Turkey, Mustafa Yaman, Remzi̇ye Nalçacioğlu, Zi̇hni̇ Demi̇rbağ Jan 2001

Viral Control Of The European Pine Sawfly, Neodiprion Sertifer (Geoffroy) In Turkey, Mustafa Yaman, Remzi̇ye Nalçacioğlu, Zi̇hni̇ Demi̇rbağ

Turkish Journal of Biology

The European pine sawfly, Neodiprion sertifer (Geoffr.) (Hymenoptera: Diprionidae), is a serious pest of pine plantations and ornamentals. Chemical pesticides used to control this pest have a detrimental effect on the environment. The Neodiprion sertifer nuclear polyhedrosis virus (NsNPV) frequently causes considerable decreases in the populations but doses not harm other animals or plants. In this study, we tested five different concentrations of NsNPV against the larvae of N. sertifer and showed viral infection using Giemsa staining. When a viral concentration of 5x10^9 PIB/ml (Polyhedral Inclusion Body) was utilized, larval mortality started on the fourth day and reached 90.4% on …

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Callus Induction And Plant Regeneration From Mature Embryos Of Oat (Avena Sativa L.), Melahat A.Bi̇rsi̇n, Sertaç Önde, Murat Özgen Jan 2001

Callus Induction And Plant Regeneration From Mature Embryos Of Oat (Avena Sativa L.), Melahat A.Bi̇rsi̇n, Sertaç Önde, Murat Özgen

Turkish Journal of Biology

The aim of this study, which was conducted in Ankara University, Faculty of Agriculture, Department of Field Crops, biotechnology laboratory in 1998-1999, was to determine the callus induction and plant regeneration capacity of oat (Avena sativa L.). The mature embryos of 10 oat genotypes were utilised for callus induction. The statistical analysis of the results revealed that callus induction and plant regeneration capacity were dependent on the oat genotype. However, a significant relationship was not established between callus induction and regeneration capacity and, furthermore, the number of regenerated plants was determined to be directly related to the callus production capacity.

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In Vitro Inhibition Of The Mycelial Growth Of Some Root Rot Fungi By Rhizobium Leguminosarum Biovar Phaseoli Isolates, İbrahi̇m Özkoç, Muhammet Hani̇fi̇ Deli̇veli̇ Jan 2001

In Vitro Inhibition Of The Mycelial Growth Of Some Root Rot Fungi By Rhizobium Leguminosarum Biovar Phaseoli Isolates, İbrahi̇m Özkoç, Muhammet Hani̇fi̇ Deli̇veli̇

Turkish Journal of Biology

In solid medium, the effects of twenty-three Rhizobium leguminosarum biovar phaseoli isolates on the mycelium development of the phytopathogenic fungi of three different genera (Fusarium oxysporum, Pythium ultimum and Rhizoctonia solani) were tested in vitro. The experiments were achieved by applying the superimpose dual culture technique. Most of the rhizobia tested inhibited the fungal development. The inhibition rates displayed differences in accordance with the bacteria and fungi isolates utilized. However, the inhibitory effect of the rhizobia occurred most on the isolates of Fusarium and Pythium species (up to 30.35% and 29.75% respectively) and least on those of Rhizoctonia species (16.03%). …

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Ga3, Aba And Cytokinin Production By Lentinus Tigrinus And Laetiporus Sulphureus Fungi Cultured In The Medium Of Olive Oil Mill Waste, Bi̇rgül Özcan, S. Fati̇h Topcuoğlu Jan 2001

Ga3, Aba And Cytokinin Production By Lentinus Tigrinus And Laetiporus Sulphureus Fungi Cultured In The Medium Of Olive Oil Mill Waste, Bi̇rgül Özcan, S. Fati̇h Topcuoğlu

Turkish Journal of Biology

The levels of endogenous form of free, bound and total-gibberellic acid (GA_3), abscisic acid (ABA) and cytokinin (zeatin) in culture medium were determined. The changes in dry weight of the mycelium, dependent on the culture periods, was examined through the use of white-rot fungus Lentinus tigrinus and brown-rot fungus Laetiporus sulphureus which were cultured in the medium of olive oil mill waste in a static culture. Spectrophotometric techniques were used to determine the amounts of endogenous GA_3, ABA and zeatin. As a result, fungi used in this study showed that they synthesized GA_3, ABA and zeatin as a primary or …

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The Evaluation Of Alkalitolerant-Mesophilic Streptomyces By Gas Chromatography And Pyrolysis Mass Spectrometry, Nevzat Şahi̇n, Kami̇l Işik, Ergi̇n Kari̇ptaş, Michael Goodfellow Jan 2001

The Evaluation Of Alkalitolerant-Mesophilic Streptomyces By Gas Chromatography And Pyrolysis Mass Spectrometry, Nevzat Şahi̇n, Kami̇l Işik, Ergi̇n Kari̇ptaş, Michael Goodfellow

Turkish Journal of Biology

Thirty-eight alkalitolerant-mesophilic Streptomyces, defined by Saddler in his numerical taxonomic study, were evaluated by gas chromotography and pyrolysis mass spectrometry. Group I Streptomyces sp. AK409 and group II Streptomyces sp. AK029 selected duplicated strains were clustered in their own groups. It was observed that the results of gas chromatography and pyrolysis mass spectrometry was in good congruance with the numerical taxonomic results. Therefore, it can be concluded that the different chemotaxonomic methods provide rapid and reproducible information for classifying biotechnologically significant Streptomyces strains.

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Germination, Emergence, And Early Growth Of Spartina Pectinata, Wade Herold Williams Jan 2001

Germination, Emergence, And Early Growth Of Spartina Pectinata, Wade Herold Williams

Dissertations and Theses @ UNI

Spartina pectinata Link is frequently omitted from lowland prairie restorations because the seed often fails to grow when planted, and inclusion is limited to plugs of young plants. Anecdotal reports indicated improvement of seed germination following stratification. The effects of seed stratification on the germination of S. pectinata seed were systematically studied. Seed was obtained from both relict populations of plants and germplasm plants as defined by Englert and White (1977). Seed from 5 different collections were subjected to 4 different seed stratifying treatments: imbibed-chilled (1 oc for 15 to 45 days); imbibed-frozen (-12°C for 4 to 7 days); or …

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Biennialism And Vernalization-Promoted Flowering In Hyoscyamus Niger: A Comparison With Arabidopsis, Michael Schläppi, Monica Patel Jan 2001

Biennialism And Vernalization-Promoted Flowering In Hyoscyamus Niger: A Comparison With Arabidopsis, Michael Schläppi, Monica Patel

Biological Sciences Faculty Research and Publications

There are genetic similarities between the biennial growth habit of Hyoscyamus niger (H. niger) and winter annual ecotypes of Arabidopsis thaliana, including the response to demethylating agents. One focus of our research group at Marquette is to determine whether FLOWERING LOCUS C (FLC) homologs or FLC-related MADS-box genes are involved in biennialism of H. niger. This review also summarizes our initial characterization of expression profiles of 4 groups of H. niger MADS-box genes. Our results suggest that B-class floral homeotic gene homologs of H. niger are differentially expressed in flowers of annual and …

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Effects Of Depolarization And Low Intracellular Ph On Charge Movement Currents Of Frog Skeletal Muscle Fibers, Edward Michael Balog, Robert H. Fitts Jan 2001

Effects Of Depolarization And Low Intracellular Ph On Charge Movement Currents Of Frog Skeletal Muscle Fibers, Edward Michael Balog, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The low intracellular pH and membrane depolarization associated with repeated skeletal muscle stimulation could impair the function of the transverse tubular (t tubule) voltage sensor and result in a decreased sarcoplasmic reticulum Ca2+ release and muscle fatigue. We therefore examined the effects of membrane depolarization and low intracellular pH on the t-tubular charge movement. Fibers were voltage clamped in a double Vaseline gap, at holding potential (HP) of 290 or 260 mV, and studied at an internal pH of 7.0 and 6.2. Decreasing intracellular pH did not significantly alter the maximum amount of charge moved, transition voltage, or steepness …

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Productivity Estimation In Halodule Wrightii: Comparison Of Leaf-Clipping And Leaf-Marking Techniques, And The Importance Of Clip Height, Joseph L. Kowalski, Hudson R. Deyoe, Terry C. Allison, James E. Kaldy Jan 2001

Productivity Estimation In Halodule Wrightii: Comparison Of Leaf-Clipping And Leaf-Marking Techniques, And The Importance Of Clip Height, Joseph L. Kowalski, Hudson R. Deyoe, Terry C. Allison, James E. Kaldy

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

We compared estimates of Halodule wrightii leaf growth rates obtained from leaf-clipping and leaf-piercing methods in a south Texas lagoon. Leaf clipping underestimated leaf production from 15 to 37% in winter and 25 to 60% in summer relative to leaf piercing. The underestimation of leaf-clipping derived growth rates were corrected using a linear regression between leaf growth rates determined by leaf-clipping and leaf-piercing methods. To examine the effect of clip height on H. wrightii leaf growth rate estimation, leaves were clipped at 0, 2, 4, 6, and 8 cm above the sediment. Leaves clipped at 2 cm exhibited the fastest …

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Volume Management In San Environment, Chang-Soo Kim, Gyoung-Bae Kim, Bum-Joo Shin Jan 2001

Volume Management In San Environment, Chang-Soo Kim, Gyoung-Bae Kim, Bum-Joo Shin

Electrical and Computer Engineering Faculty Research & Creative Works

Logical volume managers have long been key components of a storage system. Their key features are creation of logical or virtual views of physical storage devices and support for various software RAID levels. These make it possible to overcome the limits to capacity, availability and performance of a physical storage device. Most logical volume managers are operated in a single system environment. They are not adequate for SAN (storage area network) environments where several hosts share and access a logical volume at the same time. Some recent logical volume managers are run in a multi-host environment. However, they cannot support …

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Susceptibility Of Different Bean (Phaseolus Vulgaris L.) Cultivars To Agrobacterium Tumefaciens, Azi̇z Karakaya, Sebahatti̇n Özcan Jan 2001

Susceptibility Of Different Bean (Phaseolus Vulgaris L.) Cultivars To Agrobacterium Tumefaciens, Azi̇z Karakaya, Sebahatti̇n Özcan

Turkish Journal of Biology

Although several direct gene transfer techniques have been developed, Agrobacterium tumefaciens is still preferred for the transfer of foreign genes into many plant species. Perhaps the greatest weakness of A. tumefaciens is the host range limitation. Therefore, in this study, the susceptibility of different bean cultivars to oncogenic A. tumefaciens strain A281 was assessed. The cultivars 4F-2409, Karacaşehir-90, Akman-98 and Eskişehir-855 resulted in higher frequencies of tumor formation than the other cultivars tested. Tumor formation was not observed in Afyon-3, IVD-10, Göynük-98, Yunus-90 or Şehirali-90 bean cultivars. Tumor formation was observed on both the hypocotyl and epicotyl portions of the …

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Reproductive Efficiencies In The Evolution Of Life Histories, Eric Charnov Jan 2001

Reproductive Efficiencies In The Evolution Of Life Histories, Eric Charnov

Biology Faculty & Staff Publications

Darwinian fitness is expressed as the product of 2 cost/benefit ratios.

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