Inhibition of the development of Schizophyllum commune germlings by the ammonium ion

Ammonium ions at a concentration of 1 mM completely inhibitthe growth and further development of 12–15 hr germlingsof Schizophyllum commune. The NH₄⁺, inhibition of germling growthis reversed by acetate and pyruvate, but it is reversed moreeffectively by TCA intermediates. Glucose, is not effectivein reversing the ammonium inhibition. From these data it isapparent that functional TCA enzymes are present in the germlingstage and that the mechanisms for incorporating acetate andpyruvate into the TCA cycle are also operative. There may be,however, an impaired glycolytic pathway, and, as a consequence,no intermediates are supplied to the TCA cycle, making the germlingssensitive to a disruption in the TCA cycle. The possible modeof action of ammonium ions is the activation of NADP-glutamatedehydrogenase, the subsequent enhancement of glutamic acid biosynthesis,and the final depletion of TCA intermediates. ¹This investigation was supported in part by Research GrantAI-06570 from the National Institute of Allergy and InfectiousDiseases of the U.S. Public Health Service (Received January 26, 1970; )     

The presence of gibberellin A20 in Stevia rebaudiana and its significance for the biological activity of steviol

Gibberellin-like substances of stems and leaves from Steviarebaudiana were analyzed and gibberellin A₂₀ was identifiedby gas chromatography-mass spectrometry. The presence of GA₂₀in S. rebaudiana is significant for the interpretation of thegibberellin activity of steviol. It indicates that steviol,the C-13 hydroxykaurenoic acid, may function as a precursorfor C-13 hydroxy-gibberellins and not as a gibberellin analog. ¹ This work was supported by National Science Foundation GrantGB 17304 to M. R. and by a Research Grant-in-Aid from SigmaXi to L. M. A. The research described is from a dissertationsubmitted by L. M. A. in partial fulfillment of the requirementsfor the Ph.D. degree. ² Present address: Laboratory of Plant Morphogenesis, Departmentof Biology, Manhattan College, Bronx, N. Y. 10471, U. S. A. (Received June 12, 1978; )     

Localization and Binding Characteristics of a High-Affinity Binding Site for N--Acetylchitooligosaccharide Elicitor in the Plasma Membrane from Suspension-Cultured Rice Cells Suggest a Role as a Receptor for the Elicitor Signal at the Cell Surface

A high-affinity binding site for N-acetylchitooligosac-chlarideelicitor was found to localize in the plasma membrane from suspension-culturedrice cells. Binding kinetics as well as the specificity of thisbinding site corresponded well with the behavior of the ricecells to the editor. These characteristics suggest that thebinding site represents a functional receptor for N-acetylchitooligosaccharideelicitor in rice. ²Present address: Okinawa Prefectural Livestock ExperimentalStation, 2009-5 Shoshi, Nakijin-son, Okinawa, 905-04 Japan. ³Present address: School of Hygiene and Public Health, The JohnsHopkins University, 615 North Wolfe Street, Baltimore, Maryland,21205 U.S.A. ⁴Present address: University of Tenessee, Microbiology, knoxville,Tennessee, 37996 U.S.A.     

Swelling of Etiolated Oat Protoplasts Induced by cAMP and Red Light

Etiolated oat protoplasts were treated with dibutyryl cAMP tostudy possible function of cAMP in the development by measuringthe protoplast swelling. The mean diameter of protoplasts inthe absence of any chemical treatment was 33.58±1.26(SE) µm, which increased to 36.96±0.86 µmin the presence of 100 µM dibutyryl cAMP. Prostacyclin,a potent activator of adenyl cyclase, also showed a significantswelling effect (diameter 38.01±0.98 µm). Red lightalso elicited the swelling of protoplasts (40.26±0.8µm). ¹Present address: Department of Biology, Pusan National University,Pusan 607, Korea. ²Present address: Department of Horticulture, Cheju NationalUniversity, Cheju 590, Korea. ³Present address: Department of Biological Sciences, Texas TechUniversity, Lubbock, TX 79409, U.S.A. (Received June 29, 1985; Accepted November 18, 1985)     

Protein Synthesis Linked to Respiration and Phosphorylation in Intact Euglena Mitochondria

Highly purified condensed mitochondria obtained from bleachedmutant. W₁₀BSmL of Euglena gracilis Klebs var bacillaris Coriincorporate [³⁵S]methionine into protein when fortified withmalate, ADP, Mg²⁺, phosphate and a sucrose osmoticum. Twentyto twenty-five polypeptide bands were found to be labeled inorganello when the labeled protein was subjected to sodium dodecylsulfatepolyacrylamide gel electrophoresis. Methionine incorporation,but not respiration or oxidative phosphorylation, was blockedby chloramphenicol and other 70S ribosomal translation inhibitorsbut cycloheximide and ribonuclease were without effect. Inhibitorsof electron transport and uncouplers of oxidative phosphorylationwere excellent inhibitors of protein synthesis. Thus, thesemitochondrial preparations carry out protein synthesis in organellothat is linked to respiration and oxidative phosphorylation. ¹Present address: VA Hospital Outpatient Clinic, 17 Court St.,Boston, MA 02115, U.S.A. ²Present address: Laboratories de Microbiologia e Inmunologia,Universidad Catolica de Chile, Casilla 114-D, Santiago, Chile. ³Present address: Botany Department, University of Massachusetts,Amherst, MA 01003, U.S.A. (Received June 17, 1985; Accepted October 28, 1985)     

ON THE NATURE OF MOSS OXALIC ACID OXIDASE

Moss oxalic acid oxidase freed from catalase by boiling is stronglyinhibited by the "metal-complexing" compounds such as thiocyanate,azide, diethyldithiocarbamate, and hydrosulfite. Inactivatedby dialysis against thiocyanate or azide, the enzyme can bereactivated to a considerable extent by the addition of ferricsalt, cytochrome-c or hemoglobin, not by other metal ions, suchas Cu²⁺, Zn²⁺ , Mn²⁺, and Fe²⁺. Nitrate, chlorate, monoiodoacetate,and iodide also act as strong inhibitors towards moss oxalicacid oxidase. Some enzyme fractions which were obtained by the sodium sulfateprecipitation method were stimulated by Fe³⁺, but not by cytochrome-cor by other metallic ions. This stimulation was inhibited bythiocyanate, azide and monoiodoacetate. ¹ Present address: Biological Institute, University of Toyama,Toyama     

Sucrose concentration and xylem regeneration in Coleus internodes in vitro

The induction of xylem elements in inflicted wound areas ofisolated Coleus internodes was dependent upon the presence ofsucrose in the agar growth media. The number, size and wallstructure of regenerated xylem vessels were related to the concentrationof sucrose, the presence or absence of IAA, and the orientationof the stem segments on the experimental media. ¹Current address: Forest Physiology Laboratory, Forest Service,Beltsville, Maryland, U.S.A. ²Current address: Department of Botany, Rutgers University,New Brunswick, New Jersey, U.S.A. (Received September 2, 1968; )     

Immunocytochemical Localization of Uricase in Peroxisomes of Soybean Cotyledons

Antibodies specific for nodule uricase were used for immunocytochemistryto demonstrate the presence of uricase in cotyledons of soybean(Glycine max) during germination and early seedling growth.The enzyme was localized exclusively in peroxisomes. ¹Permanent address: Department of Plant Cytology and Cytochemistry,University of Lodz, Lodz, Poland ²Current address: Department of Plant Science, University ofArizona, Tucson, AZ 85721, U.S.A.     

ORNITHINE CYCLE ENZYMES IN THE BLUE-GREEN ALGA NOSTOC MUSCORUM

Cell-free extracts of a bacteria-free culture of Nostoc muscorumwere used to demonstrate the occurrence of part of the KREBS-HENSELEITornithine cycle in blue-green algae. Evidence is presented forthe conversion of ammonia and bicarbonate to carbamyl phosphateand the coupling of carbamyl phosphate to ornithtne to yieldcitrulline. Attempts to demonstrate the conversion of citrullineto arginine were not successful. ¹Present address: Scripts Institute of Oceanography, Universityof California, La Jolla, California, U.S.A. ²Present address: Department of Biochemistry and Nutrition,The University of Texas Medical Branch, Galveston, Texas, U.S.A.     

Events surrounding the early development of Euglena chloroplasts 13. Photocontrol of protein synthesis

Protein synthesis measured as leucine incorporation was followedduring the early hours of light exposure of dark-grown cellsof wild type cells of Euglena gratilis var. bacillaris and ofbleached mutants W₃BUL and W₁₀SmL which lack detectable plastidDNA. In all strains, linear rates of leucine incorporation wereobserved in dark-grown resting cells and on exposure to light,this rate increased. After about 3 hr light exposure in wildtype cells and somewhat later in the mutants, the rate of proteinsynthesis sharply declined below that of the dark-grown anddark-incubated cells. Experiments in wild type cells showedthat leucine uptake was not rate limiting for protein synthesisalthough light exposure decreased the rate of uptake. The changesin rate found during continuous labeling of wild type cellswere verified by pulse-labeling experiments in continuous light.Exposure of dark-grown wild type cells to a two hour pulse oflight produced a transient increase in the rate of leucine incorporationwhich subsequently returned in darkness to the level of thedark-grown cells which received no light; thus the changes inrate of leucine incorporation are light-dependent. Since theeffects of light on leucine incorporation can be reproducedin mutants lacking detectable plastid DNA, the photoreceptormachinery involved cannot be coded in plastid DNA, and probablyoriginates in nuclear DNA. The role of light in programmingprotein synthesis and turnover in early chloroplast developmentis discussed. ¹Supported by Grant Number GM-14595 from the National Institutesof Health. ²Microbiology trainee of the National Institutes of Health,Grant Number GM1586. Portions of the material in this paperwere taken from a dissertation submitted by S. D. S. to theGraduate Faculty of Brandeis University in partial fulfillmentof the requirements for the Ph.D. degree. Present address: Schoolof Life Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska68588, U. S. A. ³Abraham and Etta Goodman Professor of Biology and Director,Institute for Photobiology of Cells and Organdies, BrandeisUniversity, Waltham, MA, U. S. A. 02154, to whom reprint requestsshould be sent. (Received February 8, 1979; )     

A Mutant of Arabidopsis thaliana That Defines a New Locus for Glycine Decarboxylation

A novel photorespiratory mutant of Arabidopsis thaliana, designatedgld2, was isolated based on a growth requirement for abnormallyhigh levels of atmospheric CO₂. Photosynthetic CO₂ fixationwas inhibited in the mutant following illumination in air butnot in atmosphere containing 2% O₂. Photosynthetic assimilationof ¹⁴CO₂ in an atmosphere containing 50% O₂ resulted in accumulationof 48% of the soluble label in glycine in the mutant comparedto 9% in the wild type. The rate of glycine decarboxylationby isolated mitochondria from the mutant was reduced to 6% ofthe wild type rate. In genetic crosses, the mutant complementedtwo previously described photorespiratory mutants of A. thalianathat accumulate glycine during photosynthesis in air due todefects in glycine decarboxylase (glyD, now designated gld1)and serine transhydroxymethylase (stm). Because glycine decarboxylaseis a complex of four enzymes, these results are consistent witha mutation in a glycine decarboxylase subunit other than thataffected in the gld1 mutant. The two gld loci were mapped tochromosomes 2 and 5, respectively. ³Present address: Department of Crop and Soil Sciences, MichiganState University, East Lansing, MI 48824, U.S.A. ⁴Present address: Department of Applied Bioscience, Facultyof Agriculture, Hokkaido University, Kita-Ku, Sapporo, 060 Japan ⁵Present address: Department of Biology, Carnegie Institutionof Washington, 290 Panama Street, Standford, CA 94305, U.S.A.     

Plant Cell Wall Proteins: Partial Characterization of Maize Wall Proteins With Putative Roles in Auxin-Induced Growth

Antibodies raised against cell wall proteins inhibited auxin-inducedgrowth of Zea mays L. coleoptile segments. The total complementof proteins isolated from the cell walls of Zea mays seedlingswas fractionated by cation exchange and gel filtration chromatography.A procedure was developed to evaluate these cell wall-proteinfractions for their ability to reverse growth inhibition causeby specific antibody binding. Inhibition of growth was attributedto specific antibody-antigen interaction based on the observationsthat only serum containing antibodies against certain cell wallproteins inhibited growth, that gamma globulins purified fromappropriate serum samples inhibited growth, and that a specificsubfraction of isolated cell wall proteins precipitate the growthinhibiting antibody. Antigens which generated growth inhibitoryantibodies were identified as an acidic group of proteins withapparent relative molecular masses in the range of 20–25kDa. This subfraction of cell wall proteins was not effectivein hydrolyzing cell wall polysaccharides. A small amount ofcarbohydrate was found associated with this fraction and mayreflect some degree of glycosylation of some of the proteins ¹Supported in part by National Science Foundation Research GrantPCM 7818588 ²Present Address: USDA-ARS, U.S. Dairy Forage Research Center,University of Wisconsin, Madison, WI 53706 ³Present Address: Department of Vegetable Crops, Universityof California, Davis, CA 95616 (Received November 2, 1987; Accepted March 31, 1988)     

Isolation and characterization of adenosine triphosphatase from Salicornia pacifica var. utahensis

Membrane-bound ATPase associated with plasma membrane and solubleATPase associated with the cytoplasm were prepared from shootsof Salicornia pacifica var. utahensis by sucrose density gradientcentrifugation. The isolated ATPases were tolerant to high concentrationsof NaCl. The Km for membrane-bound ATPase was 1.75 mM and forsoluble ATPase, it was 1.4 mM. The relative effectiveness ofdivalent cations for stimulation of membrane-bound ATPase wasMg²⁺>Fe²⁺>Mn²⁺>Co²⁺>Cu²⁺. Soluble ATPase activitywas stimulated by Ba²⁺>Ca²⁺>Mg²⁺ and was inhibited byCu²⁺, Zn²⁺, Co²⁺ and Fe²⁺. The compounds N,N¹-dicyclohexylcarbodiimide,NaF and ADP, did inhibit the ATPases but ouabain, triphenyltinhydroxide, sodium azide, indoleacetic acid and abscisic aciddid not inhibit the ATPases from s. pacifica var. utahensis. ¹ Present address: Department of Biology, Kong-Ju National College,Kong-Ju, Korea. (Received April 1, 1980; )     

SOME PROPERTIES OF THE CYTOCHROME C REDUCING SUBSTANCE, A FACTOR FOR LIGHT-INDUCED REDOX REACTION OF CYTOCHROME C IN PHOTOSYNTHETIC LAMELLAE

Cytochrome c reducing substance (CRS), a redox substance discoveredin photoreactive lamellar fragments, was purified by Sephadexcolumn chromatography. Chromatographic behaviours of CRS ofAnabaena and spinach were essentially the same. Purified CRSof Anabaena showed an absorption spectrum having one absorptionmaximum around 260 mµ. The absorption peak disappearedon addition of excess amount of borohydride. Similar absorptionchange on borohydride addition was observed with spinach CRSpreparation. Purified preparations of Anabaena and spinach CRS supportedphotophosphorylation in spinach broken chloroplasts. The phosphorylationwas found to couple the electron flow from water to molecularoxygen. ¹This work was supported by grant GM-11300 from the NationalInstitute of Health, U. S. A. ²Present address: Institute of Applied Microbiology, The Universityof Tokyo, Tokyo, Japan.     

Periplasmic location of dissimilatory nitrate and nitrite reductases in a denitrifying phototrophic bacterium, Rhodopseudomonas sphaeroides forma sp. denitrificans

The localization of dissimilatory nitrate and nitrite reductasesof a denitrifying phototrophic bacterium, Rhodopseudomonas sphaeroidesforma sp. denitrificans, was investigated. Nitrate and nitritereductases were located in the periplasmic space of the bacteriumgrown anaerobically in the presence of nitrate either in lightor in darkness. Chromatophores showed nitrate and nitrite reductaseactivities when dithionite-reduced benzyl viologen was an electrondonor; this suggests that the enzymes were trapped inside thevesicles. ¹Present address: Japanese Red Cross Central Blood Center, Hiroo4-1-31, Shibuyaku, Tokyo 150, Japan. ²Present address: Plant Growth Laboratory, University of California,Davis, California 95616, U.S.A. (Received November 7, 1979; )     

Glutamine synthesis in germinating seeds of Cucurbita moschata

During germination, an increase in glutamine and glutamine synthetase[L-glutamate: ammonia ligase (ADP), EC 6.3.1.2 [EC] ] occurred inthe cotyledons reaching a maximum at 4 to 6 days. The enzymehad a Km of 4.5 nun for L-glutamate, and 0.67 mu for hydroxylamine.Hydroxylamine exhibited substrate inhibition kinetics. The enzymewas inhibited by calcium ion, fluoride ion and p-hydroxymercuribenzoatebut not by EDTA, sodium ion or chloride ion. The sulf hydrylinhibition was reversed by dithiothreitol. In vivo synthesisof glutamine-¹⁴C from glutamate-¹⁴C was found to parallel theincrease in glutamine content and the in vitro glutamine synthetaseactivity during germination. ¹ Present address: Department of Biology, Mercyhurst College,Erie, Pennsylvania 16501, U.S.A. (Received June 12, 1971; )     

Activation Energies of Reactions Catalyzed by the Nitrate Reductase from Chlorella vulgaris

The thermal dependence of two of the reactions catalyzed bythe nitrate reductase from Chlorella vulgaris was determined.The activation energies for NADH:nitrate oxidoreductase (EC1.6.6.1 [EC] ) and NADH:Cytochrome c oxidoreductase (EC 1.6.99.3 [EC] )are 42.1 kJ?mol^–1 and 21.5 kJ?mol^–1, respectively.Since the thermal dependency of the two enzymes is different,ratios of the activities will vary with temperature. The importanceof both rigorous thermal control during nitrate reductase assaysas well as the need to specify the temperature at which theratio of activities for the enzyme are clearly established. ¹Present Address: Cropping Systems Research Laboratory, USDA-ARS,Route 3, Box 215, Lubbock, TX 79401, U.S.A. (Received November 25, 1987; Accepted March 2, 1988)     

Effects of colchicine on the mitosis of Physarum polycephalum

Colchicine treatment delayed mitosis in the plasmodium of Physarumpolycephalum. This effect was observed when colchicine-pulsetreatments were performed at the late G2 phase. ³H-colchicine-bindingactivity was mainly localized in the nuclei and increased inthe late G2 phase. ¹ Present address: Department of Biochemistry, The Public HealthResearch Institute of The City of New York, Inc., New York,U.S.A. (Received September 22, 1977; )     

Trifluralin and root growth

Trifluralin inhibited root elongation and induced root tip swellingof Zea mays and Triticum aeslivum. Time-course experiments showedthese effects occurred within 6 hr of treatment. As the rootstreated with trifluralin enlarged, there was a concomitant increasein root growth inhibition. Bioassays were devised to quantitativelymeasure the radial enlargement of trifluralin-treated roots.Histological observations indicated that swollen root tissuewas growing in a non-polar manner. The root swelling effectof trifluralin was inhibited 70% by the reducing agent, 2,3-dimercaptopropanol.Trifluralin had no effect on SH content of root tip proteinof Z.mays. ¹ Published with the approval of the Director of die West VirginiaAgricultural Experiment Station as Scientific paper No. 1177. ² Present address: Department of Biology, Mercyhurst College,Erie, Pennsylvania 16501, U.S.A. (Received March 19, 1971; )