Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

2001

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 2161 - 2190 of 2477

Full-Text Articles in Life Sciences

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 …

Go to article

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. …

Go to article

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 …

Go to article

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.

Go to article

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.

Go to article

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.

Go to article

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.

Go to article

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, …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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.

Go to article

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 …

Go to article

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 …

Go to article

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.

Go to article

Prevalence Of Eimeria (Apicomplexa: Eimeriidae) In Reintroduced Gunnison's Prairie Dogs (Cynomys Gunnisoni), M. M. Ryan, K. H. Decker, Donald W. Duszynski Jan 2001

Prevalence Of Eimeria (Apicomplexa: Eimeriidae) In Reintroduced Gunnison's Prairie Dogs (Cynomys Gunnisoni), M. M. Ryan, K. H. Decker, Donald W. Duszynski

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Fecal samples from 54 Gunnison’s prairie dogs (Cynomys gunnisoni) from Albuquerque, NM were analyzed for the presence of coccidia and all were positive. They were then relocated to an abandoned prairie dog town on the Sevilleta Long Term Ecological Research (LTER) site. Six Eimeria species, E. callospermophili, E. cynomysis, E. pseudospermophili (new host record), E. spermophili, E. ludoviciani and E. vilasi (new host record) were found in Albuquerque animals, but only two species, E. callospermophili and E. vilasi were present in relocated hosts. A significant (P < 0.05) reduction was seen in the prevalence of E. vilasi (72% vs. 13%) and in the prevalence of infections …

Go to article

Uneasy Unions: Quality Effects Of Rye Chromatin Transfers To Wheat, Robert A. Graybosch Jan 2001

Uneasy Unions: Quality Effects Of Rye Chromatin Transfers To Wheat, Robert A. Graybosch

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A number of genes of agronomic importance have been transferred from rye (Seale cereale L.) to its close relative, common bread wheat (Triticum aestivum L). Largely through the production of interspecific chromosomal translocation and substitution lines, rye chromatin now rides within the genome of a large number of wheat breeding lines and cultivars. Rye chromosomal materials have been used to transfer resistance genes to fungal pathogens, especially rusts and powdery mildew, resistance to insect pests, and in some cases, may enhance grain yield, grain yield stability, and grain protein content. Unfortunately, the transfer of some rye chromosomal materials …

Go to article

Discovery And Deployment Of Molecular Markers Linked To Fusarium Head Blight Resistance: An Integrated System For Wheat And Barley, David Van Sanford, James Anderson, Kimberly A. Garland-Campbell, Josè Costa, Perry Cregan, Carl Griffey, Patrick Hayes, Richard Ward Jan 2001

Discovery And Deployment Of Molecular Markers Linked To Fusarium Head Blight Resistance: An Integrated System For Wheat And Barley, David Van Sanford, James Anderson, Kimberly A. Garland-Campbell, Josè Costa, Perry Cregan, Carl Griffey, Patrick Hayes, Richard Ward

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein.)], is a devastating disease that reduces yield, quality and economic value of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.).

Go to article

Net Grassland Carbon Flux Over A Subambient To Superambient Co2 Gradient, P. C. Mielnick, W. A. Dugas, H. B. Johnson, H. W. Polley, J. Sanabria Jan 2001

Net Grassland Carbon Flux Over A Subambient To Superambient Co2 Gradient, P. C. Mielnick, W. A. Dugas, H. B. Johnson, H. W. Polley, J. Sanabria

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Increasing atmospheric CO2 concentrations may have a profound effect on the structure and function of plant communities. A previously grazed, central Texas grassland was exposed to a 200-µmol mol-1 to 550 µmol mol-1 CO2 gradient from March to mid-December in 1998 and 1999 using two, 60-m long, polyethylene-covered chambers built directly onto the site. One chamber was operated at subambient CO2 concentrations (200-360 µmol mol-1 daytime) and the other was regulated at superambient concentrations (360-550 µmol mol-1). Continuous CO2 gradients were maintained in each chamber by photosynthesis during the day and …

Go to article

Clear-Sky Albedo Measured At Seven Rangland Sites In Southwest Idaho, Clayton L. Hanson Jan 2001

Clear-Sky Albedo Measured At Seven Rangland Sites In Southwest Idaho, Clayton L. Hanson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

As a component of the energy budget, albedo is used in the calculation of evapotranspiration in many natural resource and hydrologic models. There are few measurements of albedo over sagebrush-dominated rangelands, so albedo was measured at seven sites on the Reynolds Creek Experimental Watershed in southwest Idaho during 1989–1993. For all sites, the average albedo measured during midday under clear skies was 0.14 during the growing season. Albedo varied from a low of 0.11 during June at the Mountain big sagebrush site to a high of 0.17 at the low-elevation Wyoming big sagebrush site. Albedo varied little between about 2 …

Go to article

Research Needs Concerning Non-Target Impacts Of Biological Control Introductions, K.R. Hopper Jan 2001

Research Needs Concerning Non-Target Impacts Of Biological Control Introductions, K.R. Hopper

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Two workshops were held in 1999 on research needs concerning non-target impacts of biological control introductions. One took place on the Internet for 9 months, and the other in Montpellier, France, for 1 day. Altogether, over 200 researchers from over 30 countries participated, representing a wide variety of viewpoints on the issues involved. The deliberations of these workshops are summarized here. Both workshops highlighted the need for retrospective studies to: (i) identify cases of significant non-target impacts; (ii) explore mechanisms involved when such impacts are found; (iii) evaluate the reliability of host-range testing protocols; and (iv) determine whether and under …

Go to article

Innovative Remote Sensing Techniques To Increase Nitrogen Use Efficiency Of Corn, Walter C. Bausch, Kenan Diker Jan 2001

Innovative Remote Sensing Techniques To Increase Nitrogen Use Efficiency Of Corn, Walter C. Bausch, Kenan Diker

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Nitrogen (N) fertilizer recommendations made without adequate knowledge of the N supply capability of a soil can lead to inefficient use of N. Proper crediting of N from manure and legumes as well as mineralization of N from organic matter is difficult. Remote sensing techniques that use the crop to indicate its N status show considerable promise for improving N management. Objectives of this paper were twofold: 1) to compare the N Reflectance Index (NRI) calculated from ground-based radiometer measurements acquired over irrigated corn (Zea mays L.) at a nadir view (0 °) and an oblique view (75 °) …

Go to article

Absolute Pitch And Planum Temporale, Julian P. Keenan, Van Thangaraj, Andrea R. Halpern, Gottfried Schlaug Jan 2001

Absolute Pitch And Planum Temporale, Julian P. Keenan, Van Thangaraj, Andrea R. Halpern, Gottfried Schlaug

Faculty Journal Articles

An increased leftward asymmetry of the planum temporale (PT) in absolute-pitch (AP) musicians has been previously reported, with speculation that early exposure to music influences the degree of PT asymmetry. To test this hypothesis and to determine whether a larger left PT or a smaller right PT actually accounts for the increased overall PT asymmetry in AP musicians, anatomical magnetic resonance images were taken from a right-handed group of 27 AP musicians, 27 nonmusicians, and 22 non-AP musicians. A significantly greater leftward PT asymmetry and a significantly smaller right absolute PT size for the AP musicians compared to the two …

Go to article

Oxidative Metabolism In Plant/Bacteria Interactions: Characterization Of The Oxygen Uptake Response Of Bacteria, C. Jacyn Baker, Norton Mock, Kenneth L. Deahl, Bryan Bailey, Daniel P. Roberts Jan 2001

Oxidative Metabolism In Plant/Bacteria Interactions: Characterization Of The Oxygen Uptake Response Of Bacteria, C. Jacyn Baker, Norton Mock, Kenneth L. Deahl, Bryan Bailey, Daniel P. Roberts

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

An increase in oxygen uptake has been previously described in plant cell suspensions treated with bacteria or bacterial elicitors. These studies, regarding oxygen uptake, have all been undertaken from the perspective of the host plant cell reacting to the invading pathogen. In contrast, here we describe and characterize an increase in oxygen uptake by bacterial cells in response to plant suspensions or autoclaved plant cell filtrates. Autoclaved plant cell filtrates stimulated bacterial oxygen uptake by as much as sevenfold within a few minutes after addition. This oxygen uptake response was proportional to both the concentration of the plant cell filtrate …

Go to article

Oxidative Metabolism In Plant/Bacteria Interactions: Characterization Of A Unique Oxygen Uptake Response Of Potato Suspension Cells, C. Jacyn Baker, E. W. Orlandi, Kenneth L. Deahl Jan 2001

Oxidative Metabolism In Plant/Bacteria Interactions: Characterization Of A Unique Oxygen Uptake Response Of Potato Suspension Cells, C. Jacyn Baker, E. W. Orlandi, Kenneth L. Deahl

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Plant suspension cells have been shown to respond to bacteria or microbial elicitors by producing active oxygen as well as increasing oxygen uptake. Here we characterize a unique two stage oxygen uptake response of potato suspension cells to heat-killed bacteria. Stage 1 occurred within minutes after the addition of heat-killed bacteria; the potato suspension cells responded with a rapid increase in oxygen uptake and reached a steady state approximately 50 % greater than the initial basal rate. Stage 2 began 20-30 min after this new steady state was achieved and was characterized by a slow increase in the oxygen uptake …

Go to article

Induction Of Defense Responses In Tobacco By The Protein Nep1 From Fusarium Oxysporum, James C. Jennings, Patricia C. Apel-Birkhold, Norton M. Mock, C. Jacyn Baker, James D. Anderson, Bryan A. Bailey Jan 2001

Induction Of Defense Responses In Tobacco By The Protein Nep1 From Fusarium Oxysporum, James C. Jennings, Patricia C. Apel-Birkhold, Norton M. Mock, C. Jacyn Baker, James D. Anderson, Bryan A. Bailey

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Fusarium oxysporum produces a 24-kDa protein, Nep1, which induces necrosis and ethylene production in leaves of many dicot plant species. Detached Nicotiana tabacum L. cv. Xanthi leaves respond with concentration-dependent necrosis after infiltration with Nep1 or when Nep1 is taken up by the vascular tissue. This response follows the induction of ethylene biosynthesis and accumulation of ACC synthase and ACC oxidase transcripts. Pretreating the leaves with 100 µl/l ethylene prior to elicitation enhanced Nep1-induced ethylene production. Nep1 (208 nM) causes extensive necrosis of mature tobacco leaf tissue when applied to Xanthi tobacco as a foliar spray (129 ml/m2). …

Go to article

Conservation And Evaluation Of Natural Enemies In Ipm Systems For Bemisia Tabaci, Steven E. Naranjo Jan 2001

Conservation And Evaluation Of Natural Enemies In Ipm Systems For Bemisia Tabaci, Steven E. Naranjo

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Conservation biological control emphasizes the preservation and enhancement of natural enemies and is the cornerstone of all approaches to biological control. This review critically examines recent and current research efforts in conservation biological control by predators and parasitoids of Bemisia tabaci worldwide. A large number of natural enemy species have been identified from many agricultural systems. Further research has demonstrated that these natural enemies may act along with other mortality agents to inflict high levels of mortality on populations of B. tabaci. Less effort has been placed on determining the factors constraining or potentially enhancing biological control. The widespread …

Go to article

Managing Crop Residue With Green Manure, Urea, And Tillage In A Rice–Wheat Rotation, Milkha S. Aulakh, T. S. Khera, John W. Doran, Kevin F. Bronson Jan 2001

Managing Crop Residue With Green Manure, Urea, And Tillage In A Rice–Wheat Rotation, Milkha S. Aulakh, T. S. Khera, John W. Doran, Kevin F. Bronson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Most double-crop grain farmers in South Asia remove or burn cropresidue to facilitate seedbed preparation and to avoid possible yield reductions. This results in loss of soil organic matter (SOM) and nutrients. In this study, we determined whether incorporating wheat (Triticum aestivum L.) residue, rice (Oryza sativa L.) residue, and sesbania (Sesbania aculeta L.) green manure with urea fertilizer N in a rice–wheat cropping system can improve grain yields, N use efficiency, and SOM. We incorporated wheat residue (6 Mg ha-1, C/N = 94), rice residue (6 Mg ha-1, C/N = 63), or …

Go to article

First Prev Next Last