BOOK REVIEWS

Seeliger, U. (ed.). 1992. Coastal Plant Communities of Latin America. xx + 392 pp. Academic Press, San Diego, CA. ISBN 0-12 634550-3. Price: USD 75.-. Short reviews R. Pott (ed.). 1989. Rintelner Symposium I. Berichte der Reinhold-Tüxen-Gesellschaft 1 , 165 pp. Reinhold-Tüxen-Gesellschaft, Institut für Geobotanik, Nienburger Str. 17, D-3000 Hannover, Germany. ISBN 3-88452-775-4. Price: not indicated. R. Pott (ed.). 1991. Berichte der Reinhold-Tüxen-Gesellschaft 3 , 291 pp. ISBN 3-88452-776-2. Price: DEM 55.-. Hügin, Gerhard & Henrichfeise, Alfons. 1992. Naturschutzbewertung der badischen Oberrheinaue. Vegetation und Wasserhaushalt des rheinnahen Waldes. 48 pp + maps. Schriftenreihe für Vegetationskunde 24. Bundesforschungsanstalt für Naturschutz und Landschaftsökologie, Bonn-Bad Godesberg. ISBN 3-7843-2072-4. Preis DEM 10.-. Duhme, F., Lenz, R. & Spandau, L. (eds). 1992. 25 Jahre Lehrstuhl für Landschaftsökologie in Weihenstephan mit Prof Dr. Dr. h.c. W. Haber. Landschaftsökologie Weihenstephan 6. Freunde der Landschaftsökologie Weihenstephan, Ziegelgasse 19, D-8050 Freising, Germany. ISBN 3-922318-06-1. Price: not indicated.     

Identification and distribution of profilin in tomato (Lycopersicon esculentum Mill.)

Profilin is a G-actin monomer-binding protein which has been shown to participate in actin-based tipgrowth of animal cells. The abundance of profilin in pollen and its occurrence in several vegetable foods raises the question of the role of profilin in plants. First, its distribution throughout various parts of the plant needs to be determined. This paper describes observations on the presence of profilin in the tomato plant (Lycopersicon esculentum Mill.). The distribution of profilin in flower buds, stems, leaves, roots, and fruits of tomato was determined by immunoblotting and by tissue printing, showing that profilin is present in most if not all parts of the tomato plant.We gratefully acknowledge the help provided by Dr. A.T. Jagendorf and the donation of tomato seeds and maize pollen by N. Eanetta and Dr. M. Smith, respectively. The use of Dr. R. Wayne's SZH ILLD dissecting microscope is gratefully acknowledged. This work was aided by helpful discussions with C.S. Combs, Dr. C.A. Conley, and Dr. J. Andersland. This work was supported by a Hatch grant and NRI Competitive Grants Program/USDA 94-37304-1046 to MVP. This material is based upon work supported under a National Science Foundation Graduate Research Fellowship to DWD.     

Buchbesprechungen

Abstract

Prof. Dr. J. B. S. Braverman: Introduction to the Biochemistry of Foods (Einführung in die Biochemie der Nahrungsstoffe). — Erschienen bei Elsevier Publishing Company, Amsterdam/London/New York, 1963, 336 Seiten mit 55 Abbildungen und 12 Tabellen, Ganzleinen, Preis: Dfl. 35,—, DM 39,—, sh. 70. Reviewed by H. Bergner.

F. F. Nord: Advances in Enzymology and related Subjects of Biochemistry (Fortschritte in der Enzymologie und den verwandten Gebieten der Biochemie), Band 26. — Erschienen bei Interscience Publishers, John Wiley & Sons, New York/London/Sydney, 1964, 453 Seiten, Preis: 94 s. Reviewed by H. Bergner.

Prof. Dr. W. Becker und Prof. Dr. Dr. h. c. K. Nehring: Handbuch der Futtermittel (in drei Bänden), Band 2. — Erschienen beim Verlag Paul Parey, Hamburg, 1965, XX und 475 Seiten mit 907 Tabellen, Ganzleinen, Subskriptionspreis: DM 144.—. Reviewed by H. Bergner.

Prof. Dr. W. Schuphan: Zur Qualität der Nahrungspflanzen. Erzeugerinteressen — Verbraucherwünsche. — Erschienen bei BLV Verlagsgesellschaft, München/Bonn/Wien, 1961, 170 Seiten mit 59 Abbildungen und 25 Tabellen, Format 15,8 × 23,5 cm, Leinen, Preis: DM 19,80. Reviewed by A. Püschner.

Das Kalium und die Qualität landwirtschaftlicher Produkte (Grünfutter, Steinund Kernobst, Kartoffeln). — Bericht über das 2. Regional-Kolloquium des Internationalen Kali-Institutes, Murten (Schweiz), erschienen beim Verlag Internationales Kali-Institut, Bern 14 (Schweiz), 1964, 208 Seiten, Preis: Sfr. 10,—; US $ 2,40. Reviewed by A. Püschner.

Prof. Dr. Dr. h. c. Victor Goerttler: Vom literarischen Handwerk der Wissenschaft. Eine Plauderei mit Zitaten und Aphorismen. — Erschienen beim Verlag Paul Parey, Berlin und Hamburg, 1965, 284 Seiten, Ganzleinen, Preis: DM 26,—. Reviewed by H. Bergner.     

Chemische Zusammensetzung des Lipopolysaccharids eines Stammes von Rhizobium lupini

Die chemische Zusammensetzung des Lipopolysaccharids des Stammes R. lupini 16–2 wurde untersucht. Der Lipidanteil enthält die Fettsäuren Hydroxymyristinsäure, Myristinsäure und Palmitinsäure im molaren Verhältnis 4:1: 1. Folgende Zuckerkomponenten konnten nachgewiesen werden: Glucosamin, Galaktosamin, 2-Keto-3-desoxyoctonat (KDO), Rhamnose und wahrscheinlich Heptose. Der Phosphatgehalt betrug 2% (w/w). Rhamnose stellt 37% (w/w) des Gesamt-LPS dar. Dieser Zucker bildet wahrscheinlich die O-spezifischen Seitenketten. Diese Arbeit wurde von der Deutschen Forschungsgemeinschaft unterstützt. Herrn Prof. Dr. K. Jann und Frau Dr. B. Jann möchten wir sehr herzlich für anregende Diskussionen danken. Frau Dr. I. Fromme danken wir für die Hilfe bei der gaschromatographischen Analyse.     

Regeneration in the central nervous system of a pulmonate mollusc,Melampus

Summary The left cerebral ganglion was ablated from 72 anesthetized, adult Melampus bidentatus (Mollusca: Pulmonata). Skin incisions were well healed and normal feeding and locomotion observed four days after surgery. Dissections of animals sacrificed weekly showed that most nerves and connectives regrew within 30 days, attaching to the swollen end of the major labial nerve. The enlarged end of this nerve later developed into a distinctive bud; some of these buds contained cell bodies as soon as 42 days after surgery. As the first known report of central nervous tissue regeneration in molluscs, this study points to the need for controls in experiments involving section or ablation of nervous tissue in molluscs.I am grateful to Dr. W.D. Russell-Hunter for his guidance in the course of this work. Support was principally provided by a grant from the National Science Foundation to Dr. Russell-Hunter (Research Grant No. GB-36757 continued as BMS-72-02511-A01)and by two successive grants to the author from the Theodore Roosevelt Memorial Fund of the American Museum of Natural History, New York     

Model membranes: Spherical shells bounded by one bimolecular layer of phospholipids

Summary The conditions are described which lead to the formation of small spherical vesicles bounded by singlelipid membranes. These membranes appear as triple-layered structures in electron micrographs and thus resemble theunit membrane configuration of cellular boundaries. The theory of light scattering by spherical shells is found applicable to the vesicles described here; size determinations by electron microscopy (r=195 Å) and by light scattering (r=225 Å) give reasonably close values. The refractive index of the membranes as determined by differential refractometry is found to be 1.46 for green incident light of wavelength 5461 Å.The results of this work were presented in part at the Symposium on Biophysical Aspects of Permeability, Jerusalem, Israel, July 2–9, 1968.I gratefully acknowledge the help provided me during this work by Dr Walter Stoeckenius, and I also thank Dr Dominic Dziewiatkowski for the permission to use his light scattering photometer.This work was supported by grant No. GB-4871 from the National Science Foundation.     

Autoactive molluscan neuron: Reflex function and synaptic modulation during feeding in the terrestrial slug,Limax maximus

Summary The salivary burster (SB) is an autoactive motoneuron to the salivary duct of the terrestrial slugLimax maximus. The SB is electrically coupled to protractor motoneurons and inhibited by the metacerebral giant cell. During feeding these synaptic inputs cause SB activity to be phase-locked to the protraction-retraction cycle. The SB can be used as a clear and reliable monitor of feeding motorprogram activation.We thank Dr. Joseph Jin Chang for invaluable assistance with some of this work. Support was provided by NSF grant BMS74-15217 to D.J.P., NSF grant BMS74-03572 to A.G., and a grant from the Spencer Foundation.     

Buchbesprechung

Abstract

Herausgegeben von Prof. Dr. Dr. h.c. mult. Manfred Kirchgessner Freising-Weihenstephan

Unter Mitwirkung zahlreicher Wissenschaftler

Heft 22 der “Fortschritte in der Tierphysiologie und Tierernährung”; Beihefte zur “Zeitschrift für Tierphysiologie, Tierernährung und Futtermittelkunde” (“Advances in Animal Physiology and Animal Nutrition”; Supplements to “Journal of Animal Physiology and Animal Nutrition”)

1991. 120 Seiten. Mit 41 Abbildungen und 58 Tabellen.

25 × 17 cm. Kartoniert 62, — DM. ISBN 3-490-42215-5-. Verlag Paul Parey. Hamburg und Berlin Reviewed by A. Püschner. Reviwed by A. Püschner.     

Buchbesprechungen

Abstract

O. Kellner und M. Becker: Grundzüge der Fütterungslehre — Erschienen beim Verlag Paul Parey, Hamburg und Berlin, 14. neubearbeitete Auflage, 1966, 325 Seiten mit 81 Tabellen im Text, Format 15,2 × 22,7 cm, Ganzleinen, Preis: DM 28,80 — kartonierte Studienausgabe: DM 22,80. Reviewed by H. Bergner.

Prof. Dr. M. Becker und Prof. Dr. Dr. h. c., Dr. h. c., Dr. h. c. K. Nehring: Handbuch der Futtermittel (in drei Bänden), Band 3. — Erschienen beim Verlag Paul Parey, Hamburg, 1967, 439 Seiten mit 281 Tabellen, Ganzleinen, Subskriptionspreis, der zum Bezug aller drei Bande verpflichtet: DM 128, Einzelpreis DM 156. Reviewed by H. Bergner.

Dipl.-Landw. Rudolf Kiffmann: Illustriertes Bestimmungsbuch für Wiesen- und Weidepflanzen des mitteleuropäischen Flachlandes Teil C: Schmetterlingsblütler (Papilionatae) — Erschienen im Selbstverlag des Verfassers, Dipl.-Landw. R. Kiffmann, (A-8010) Graz/Stmk. Geidorfgürtel 34 Österreich. Zweite Auflage 1966, 65 Seiten und 130 Abbildungen, Kunstdruckpapier, geheftet, Format 19,0 × 13,0 cm, Preis: DM 4,70. Reviewed by A. Püschner.

Das Kalium und die Qualität landwirtschaftlicher Produkte (Weizen, Mais, Hopfen, Gerste) — Bericht über das 4. Regional-Kolloquium des Internationalen Kali-Institutes Belgrad (Jugoslawien) 1965. Verlag Internationales Kali-Institut 3000 Bern 14 (Schweiz). Reviewed by A. Püschner.

Autorenkollektiv: Deutsch-russisches landwirtschaftliches Wörterbuch — Erschienen beim Verlag ?Sowjetskaja Enziklopedija“, Moskau. 2. verbesserte und erweiterte Auflage, 1965, 684 Seiten, Format 12,5 × 20,0 cm, Ganzleinen, Preis: M 11,55. Reviewed by H. Bergner.     

Purification and characterization of isoforms of cinnamyl alcohol dehydrogenase fromEucalyptus xylem

Two distinct isoforms of cinnamyl alcohol dehydrogenase, CAD 1 and CAD 2, have been purified to homogeneity from xylem-enriched fractions ofEucalyptus gunii Hook and partially characterized. They differ greatly in terms of both physical and biochemical properties, and can be separated by hydrophobic interaction chromatography on Phenyl Sepharose CL-4B. The native molecular weight of of CAD 1 is 38 kDa as determined by gel-filtration chromatography on Superose 6, and this isoform is likely to be a monomer since it yields a polypeptide of 35 kDa upon sodium dodecyl sulfatepolyacrylamide gel electrophoresis. It has a low substrate affinity for coniferyl andp-coumaryl alcohols and their corresponding aldehydes. No activity with sinapyl aldehyde and alcohol was detected. The more abundant isoform is CAD 2, which has a native molecular weight of 83 kDa and is a dinier composed of two subunits of slightly different molecular weights (42–43 kDa). These subunits show identical peptide patterns after digestion with N-chlorosuccinimide. The isoform, CAD 2, has a high substrate affinity for all the substrates tested. The two isoforms are immunologically distinct as polyclonal antibodies raised against CAD 2 do not cross-react with CAD 1. The characterization of two forms of CAD exhibiting such marked differences indicates their involvement in specific pathways of monolignol utilisation.Abbreviations CAD cinnamyl alcohol dehydrogenase - DTT dithiothreitol - NCS N chlorosuccinimide - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis This work was supported by the European Economic Community project AGRE 0021 (OPLIGE) in the scope of the ECLAIR PROGRAMME. The authors whis to thank Drs. L. Davin and N. Lewis (Washington State University) for kindly providing synthesized substrates, Dr. Annie Boudet for excellent technical assistance, and Dr. M. Campbell for fruitful discussions (Université Paul Sabatier, Toulouse, France). We would also like to thank Dr. M. M. Cordonnier-Pratt and Dr. L. Pratt (University of Georgia, Athens, USA) for helpful advice and antibody production.     

Chemische Untersuchungen über unterschiedlich vorbehandelte Federmehle

Abstract

Dr. Carlheinrich Engelmann: Ernährung und Fütterung des Geflügels. Erschienen im Neumann-Verlag Radebeul/Berlin, 162 Seiten, 17 × 24 cm Halbleinen, MDN 6,80. Reviewed by H. Bergner

Dr. Martin Pankrath: Wasserbedarf landwirtschaftlicher Nutztiere — Mengennormen. - Erschienen im S. Hirzel Verlag, Leipzig C 1, Schuhmachergäßchen 1–3. 1. Auflage 1963, 99 Seiten mit 25 Diagrammen, 21 Tabellen und 2 Tafeln im Text. 8°, Hln., MDN 10,70. Reviewed by H. Bergner

Physiologische und wirtschaftliche Leistungsgrenzen in der Tierzucht 14 Vorträge eines internationalen Symposions im Max-Planck-Institut für Tierzucht und Tierernährung in Mariensee vom 14. bis 17. Oktober 1963.: Herausgegeben von M. Witt. 315 Seiten mit 8 Kunstdrucktafeln. Englische Summaries. Steif broschiert, Preis DM 16,-. Bestellung über Institut. Reviewed by H. Bergner     

The postcranial skeletons of the Triassic mammals Eozostrodon, Megazostrodon and Erythrotherium.

The purposes of this monograph are to describe the postcranial skeletons of the earliest known mammals, and to probe, in so far as possible by osteological study, biological questions concerning the habits and adaptations of these late Triassic forms. In this context, information on the background of this investigation is useful. Studies of Mesozoic mammals, begun some 150 years ago, are based on rare and fragmentary fossils, principally jaws and teeth. These investigations have yielded a bare outline of some 120 million years of mammalian evolution-about two-thirds of mammalian history. No assessment of the important biological changes occurring during this time can ever be complete, but major advances are possible as new discoveries provide material that is more complete or that represents a previously unknown evolutionary stage. So tenuous is the evidence that at least some concepts are re-evaluated with each discovery. Postcranial anatomy offers especially intriguing prospects for investigation because associated material (that can be positively assigned to a taxon below subclass) has been for the most part unknown, and indeed even dissociated bones are a rarity. Since G.G. Simpson's monographs of 1928 and 1929, progress in the study of Mesozoic mammals has been largely dependent on new finds. A major impetus to renewed investigation came from the discoveries of Mesozoic mammals by Walter Kühne in 1939 and during the immediate post-war years. Kühne first worked on fissures in the Carboniferous limestone quarries at Frome, Somerset, in southwest England where he collected a series of teeth of the problematical form Haramiya and two triconodont teeth which were placed in the genus Eozostrodon (Parrington 1941, 1946). The fissure faunas are generally thought to be of Upper Triassic (Rhaetic) age (Kühne 1946), although Kermack, Musset & Rigney (1973) believe that the evidence is insufficient to determine whether the deposits are Rhaetic or Lower Liassic. After the war Kühne carried his explorations farther west, eventually reaching the quarries at Bridgend in Glamorgan, Wales, where he not only found more triconodont teeth in some quantity (Kühne 1958) but also a symmetrodont tooth (Kühne 1950). Shortly after making these discoveries, Kühne returned to Germany and the work was continued by a team from University College, London, under the leadership of Dr K.A. Kermack.     

The appearance of monoamines in the adult and developing neurohypophysis of Gallus gallus

Summary Most of the specific monoamine fluorescence of the fowl neurohypophysis is found in the eminentia mediana and the infundibular stem. The densest accumulation of fluorescent structures is located to the zona externa and the subependymal layer, whereas generally only scattered fluorescence is demonstrable in the fiber layer. The neural lobe tissue is provided with very fine smooth fibers often difficult to distinguish. Spectrofluorimetric determinations have shown that noradrenaline is the major catecholamine in the chick neurohypophysis. From the embryological studies it is evident that the monoamine fluorescence first appears in the subependymal layer, the fiber layer and the neural lobe (after about 15 days of incubation). The zona externa fluorescence is not visible until just before hatching. 10 days after hatching the fluorescence intensity of the chick neurohypophysis is similar to that of the adult. Some comparisons are also made with the appearance of monoamines in the mouse.The authors take great pleasure in expressing their warmest thanks for laboratory facilities and good advice provided by Dr. Bengt Falck at the Institute of Histology, Lund, Sweden.This work was supported by grants from the Swedish Natural Science Research Council (project no. 99-35 and 2180-16), from the United States Public Health Service (NB-06701-02) and from the Swedish Medical Research Council (B-69-14 x -56-05 C).     

Besprechungen

Book Reviewed in this article: Streble, Heinz, und Dieter Krauter (1973): Das Leben im Wassertropfen, Mikroflora und Mikrofauna des Süßwassers, ein Bestimmungsbuch. Nachtigall, Werner (1972): Konstruktionsmorphologie: Funktionelle Gestaltung biologischer Stützelemente und Trägerstrukturen. Schmidt, Konrad (1972): Vergleichende morphologische Untersuchungen an Mechanorezeptoren der Insekten. Grzimeks Tierleben, 2. Ergänzungsband (1973): Unsere Umwelt als Lebensraum (Ökologie). Armstrong, Edward A. (1973): A study of bird song (Vom Vogelgesang). Sambraus, Hans Hinrich (1973): Das Sexualverhalten der domestizierten einheimischen Wiederkäuer. Dorst, Jean, und Pierre Dandelot (1973): Säugetiere Afrikas, aus dem Englischen (2. Aufl. 1970) übersetzt und bearbeitet von Prof. Dr. Herwart Bohlken und Dr. Hans Reichstein. Rensch, Bernhard (1973): Gedächtnis, Begriffsbildung und Planhandlungen bei Tieren. Höpp, Gerhard (1970): Evolution der Sprache und Vernunft. Springer-Verlag, 167 S. v. Frisch, Karl (1973): Erinnerungen eines Biologen. 3. Aufl.     

Festkolloquium and Symposium "Präadaptation in der Evolution von Pflanze and Tier"

Zum Gelingen dieses Symposiums haben viele entscheidend beigetragen. Tatkräftige Hilfe bei der Organisation habe ich vielen Mitgliedern des Institutes zu verdanken. Stellvertretend für alle sollen nur Frau Dr. C. Gack and meine technische Assistentin, Frau Christine Gutmann , besonders crwähnt werden. Großzügige finanzielle Unterstützung erhielten wir von der Fa. Goedecke (Freiburg) und dem Herder-Verlag (Freiburg).     

Die Morphologie der Nasenhöhle bei einigen neotropischen Chiropteren

Zusammenfassung Die Anatomie der Nasenh?hle und die Verteilung des Riechepithels wurden an sechs neotropischen Fledermausarten untersucht (Phyllostomus discolor, Glossophaga soricina, Carollia perspicillata, Sturnira lilium, Artibeus lituratus, Desmodus rotundus). Die fünf Vertreter der Phyllostomatidae besitzen ein ?hnlich gestaltetes Riechorgan (3 Endoturbinalia, 2 Ektoturbinalia). Die Vampirfledermaus (Desmodontidae) unterscheidet sich im Bau der Nase deutlich von den Blattnasen (4 Endoturbinalia, 2 Ektoturbinalia). Auch die Anheftung der Muscheln in der Nasenh?hle erfolgt bei beiden Familien in charakteristischer Weise. Alle untersuchten Arten besitzen ein gut ausgebildetes Vomeronasalorgan. Der Nasenaufbau vonMyotis myotis undRhinolophus ferrum-equinum wird unter vergleichenden Aspekten diskutiert.

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The morphology of the nasal cavity in some neotropical chiroptera

Summary The anatomy of the nasal cavity and the distribution of the olfactory epithelium has been investigated in six neotropical bat species (Phyllostomus discolor, Glossophaga soricina, Carollia perspicillata, Sturnira lilium, Artibeus lituratus, Desmodus rotundus). The five representatives of the Phyllostomatidae show a similary constructed olfactory organ (3 endoturbinals, 2 ectoturbinals), the vampire bat (Desmodontidae) differs markedly in its nasal structures (4 endoturbinals, 2 ectoturbinals). The turbinais are attached in a characteristic matter in both families. All the species investigated have a well developed vomeronasal organ. The nasal anatomy ofMyotis myotis andRhinolopbus ferrum-equinum is discussed in comparison to the neotropical species.

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Herrn Professor Dr. H. Schneider danken wir für die freundliche Unterstützung dieser Arbeit, Herrn Dr. H. Erkert für die überlassung von Tiermaterial     

Röntgen-Mikroanalyse von Barium,Schwefel und Strontium in Statolithen-Kompartimenten von Chrara-Rhizoiden

Sechs Spezies der Gattung Chara von zehn Standorten akkumulieren Barium, Schwefel und (in einigen Fällen auch) Strontium in den Statolithen-Kompartimenten ihrer Rhizoide. Hinweise auf Fundorte von Chara verdanken wir Herrn Prof. Dr. H. Fischer , Bonn, Frau Dipl.-Biol. U. Friedrich und Herrn Dipl.-Biol. P. Gerstberger , Bonn, Herrn Prof. Dr. R. Jarosch , Salzburg, sowie Friedrich (1975), Krause (1969) und Schauer (1979). Herr Dr. M. Boecker , Bonn, hat freundlicherweise die Determination der Spezies übernommen. Frau G. Hampel danken wir für Hilfe bei der Präparation. Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Half-lives of oat mRNAs in vivo and in a polysome-based in-vitro system

We have used a cell-free polysome-based in-vitro mRNA-degradation system to investigate the halflives of plant cell mRNAs. In order to establish the fidelity of the in-vitro system, we used cordycepin to determine the in-vivo half-lives of -tubulin and actin mRNAs in the primary leaves of 4-d-old etiolated oat (Avena sativa L.) seedlings. The in-vitro rank order of half-lives for phytochrome A (45 min), -tubulin (105 min), and actin (220 min) mRNAs mimicked the in-vivo rank order. A pulse of red light given to excised etiolated primary leaves caused an in-vivo reduction in the half-life of -tubulin mRNA. The selectivity of the polysome-based system was further demonstrated by the decrease in the half-life of -tubulin mRNA (from 105 min to 60 min) induced by a pulse of red light given to the etiolated oat seedlings prior to isolation of polysomes. Red light did not affect the apparent half-lives of phytochrome A or actin mRNAs.Abbreviations cab gene for chlorophyll-a/b-binding protein - kb(p) kilobase (pair) - phyA gene for type-I phytochrome protein - rbcS gene for ribulose-1,5-bisphosphate-carboxylase small-subunit We thank Dr. Richard B. Meagher for the pSAc3 actin clone. We thank Dr. Cecil Stewart for the use of his density-gradient fractionator, and Dr. Virginia Crane for instruction in using the fractionator. We also appreciate the helpful comments provided by the other members of the laboratory during the course of this research: Dr. Isaac John, Dr. Iffat Rahim, Linda Barnes, Bruce Held, David Higgs, and Theresa Tirimanne. This work was supported by USDA grants CRGO 88-37261-4196 and 91-37304-6397, and the Iowa State University Biotechnology Program.