Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters
Jul 1997
Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters
Winfried S. Peters
Wounding-induced extracellular pH shifts were characterized previously in excised segments of maize (Zea mays L.) coleoptiles. In the present study it is demonstrated that similar pH shifts also occur in Triticum aestivum L., Secale cereale L., Hordeum vulgare L., Avena sativa L., Sorghum durra (Forsk.) Stapf, and Setaria italica (L.) Beauv., with characteristic quantitative differences between the species. Indole-acetic acid induces pronounced drops of the medium pH in all species except Setaria italica.
Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle
Jun 1997
Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle
Winfried S. Peters
In excised Zea mays L. coleoptiles incubated in aerated media at high fresh weight per volume ratios, indole-3-acetic acid induces transient drops of extracellular pH. Based on the quantitative dependency of the response on the initial auxin concentration we developed a novel auxin bioassay, which allows reliable estimation of IAA concentrations between 10−8.5 and 10−5 M. Using the bioassay and complementary concentration measurements by IAA fluorescence we found the transient IAA-induced pH response paralleled by a decrease of auxin activity and concentration in the medium. This decline is rapid and starts immediately upon auxin addition, and insofar differs from the …
Spiroplasma Chrysopicola Sp. Nov., Spiroplasma Gladiatoris Sp. Nov., Spiroplasma Helicoides Sp. Nov., And Spiroplasma Tabanidicola Sp. Nov., From Tabanid (Diptera: Tabanidae) Flies, Robert F. Whitcomb, Frank E. French, Joseph G. Tully, Gail E. Gasparich, David L. Rose, Patricia Carle, Joseph M. Bove, Roberta B. Henegar, Meghnad Konai, Kevin J. Hackett, Jean R. Adams, Truman B. Clark, David L. Williamson
Jun 1997
Spiroplasma Chrysopicola Sp. Nov., Spiroplasma Gladiatoris Sp. Nov., Spiroplasma Helicoides Sp. Nov., And Spiroplasma Tabanidicola Sp. Nov., From Tabanid (Diptera: Tabanidae) Flies, Robert F. Whitcomb, Frank E. French, Joseph G. Tully, Gail E. Gasparich, David L. Rose, Patricia Carle, Joseph M. Bove, Roberta B. Henegar, Meghnad Konai, Kevin J. Hackett, Jean R. Adams, Truman B. Clark, David L. Williamson
Gail Gasparich
Four spiroplasma strains, DF-1T, TG-1T, TABS-2T, and TAUS-1T, all of which were isolated from deerflies or horseflies (Diptera: Tabanidae), were serologically distinct from previously described spiroplasma species, groups, and subgroups. Strain DF-1Toriginated from a Maryland deerfly (Chrysops sp.); strain TG-1Twas isolated from a Maryland horsefly (Tabanus gladiator); strain TAUS-1Toriginated from a member of the Tabanus abdominalis-limbatinevris complex of horseflies collected in Maryland; and strain TABS-2Twas isolated from a horsefly (Tabanus abactor) collected in Oklahoma. Cells of all of the strains appeared to be helical and motile when they were examined by dark-field microscopy. Cells of strain DF-1Tgrowing in M1D medium …
The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein
Mar 1997
The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein
Winfried S. Peters
Relative elemental growth rate (REGR) profiles describe spatial patterns of growth intensity; they are indispensable for causal growth analyses. Published methods of REGR profile determination from marking experiments fall in two classes: the profile is either described by a series of segmental growth rates, or calculated as the slope of a function describing the displacement velocities of points along the organ. The latter technique is usually considered superior for theoretical reasons, but to our knowledge, no comparative methodological study of the two approaches is currently available. We formulated a model REGR profile that resembles those reported from primary roots. We …
The Spiroplasma Motility Inhibition Test, A New Method For Determining Intraspecific Variation Among Colorado Potato Beetle Spiroplasmas, Kevin J. Hackett, J. J. Lipa, G. E. Gasparich, D. E. Lynn, M. Konai, M. Camp, R. F. Whitcomb
Dec 1996
The Spiroplasma Motility Inhibition Test, A New Method For Determining Intraspecific Variation Among Colorado Potato Beetle Spiroplasmas, Kevin J. Hackett, J. J. Lipa, G. E. Gasparich, D. E. Lynn, M. Konai, M. Camp, R. F. Whitcomb
Gail Gasparich
The Colorado potato beetle, Leptinotarsa decemlineata, is a major holarctic pest of solanaceous crops. Presumably, this insect spread from Solanum species in central America to the Mexican plateau, and this was followed by multiple invasions of North America and Europe. Attempts are being made to control this beetle by using a genetically modified spiroplasma that occurs naturally in its gut. In the current study, spiroplasmas isolated from beetles collected in North America and Poland exhibited serologic (spiroplasma motility inhibition test) and genomic (restriction fragment length polymorphism) profiles that suggest that there were multiple spiroplasma introductions. Two serovars were identified; one …
