Sodium Requirement of Monocotyledonous C4 Plants for Growth and Nitrate Reductase Activity

The effects of Na application on growth and nitrate reductaseactivity of seven C₄ plant species, Zea mays, Echinochloa crus-galli,Panicum miliaceum, Panicum coloratum, Panicum dichotomiflorum,Panicum maximum and Chloris gayana were studied. Except forZ. mays and P. miliaceum, Na application enhanced growth significantly,and concurrent increases in nitrate reductase activities weredetected in Panicum coloratum, Panicum dichotomiflorum, Panicummaximum and Chloris gayana. ¹Present address: International Research Institute, Ciba GeigyJapan Ltd., Takarazuka, Hyogo 665, Japan. ²Present address: Photobiology Lab., Research Institute forFood Science, Kyoto Univ., Uji, Kyoto 611, Japan. (Received May 2, 1988; Accepted August 22, 1988)     

The Deduced Amino Acid Sequence of Phytochrome from Adiantum Includes Consensus Motifs Present in Phytochrome B from Seed Plants

A cDNA for the phytochrome of the fern Adiantum capillus-venerisL. was cloned and sequenced. The deduced phytochrome is 50{smalltilde}55% identical to phytochromes of seed plants, and 68%identical to Selaginella phytochrome. Regions resemble thosein previously characterized phytochromes from ferns, lower plantsand seed plants. ³Present address: Yamanouchi Pharmaceutical Co., Ltd., 21 Miyukigaoka,Tsukuba-shi, Ibaraki, 305 Japan ⁴Present address: Plant Growth Regulation Laboratory, The Instituteof Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi,Saitama, 351-01 Japan ⁵Present address: Advanced Research Laboratory, Hitachi, Ltd.,Hatoyama, Saitama, 350-03 Japan     

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.     

Photoconversion of protochlorophyll to chlorophyll a in a mutant of Chlorella regularis

Dark-grown cells of a mutant strain of Chlorella regularis containedchlorophyll a and protochlorophyll, phytyl ester of protochlorophyllide.Under illumination, protochlorophyll was quantitatively anddirectly converted into chlorophyll a. The photoconversion wasdependent on light intensity and temperature and proceeded ina cell-free preparation. The pathway of chlorophyll formation found in the mutant cellsis entirely different from that from protochlorophyllide byway of chlorophyllide a, which is generally observed in greenplants. ¹Present address: Division of Biology, Medical College of Miyazaki,Miyazaki 889-16, Japan. ²Present address: Division of Environmental Biology, The NationalInstitute for Environmental Studies, Ibaragi 300-21, Japan. (Received October 24, 1975; )     

Induction of Cytosolic Acetyl-Coenzyme A Carboxylase in Pea Leaves by Ultraviolet-B Irradiation

Levels of subunits of two acetyl-coenzyme A carboxylases werehigh in small leaves of Pisum sativum, decreased with growth,and remained constant in fully expanded leaves. Irradiationof fully expanded leaves induced the cytosolic isozyme only.This result suggests a key role for the cytosolic enzyme inprotection against UV-B. ¹Present address: Laboratory of Molecular Genetics, BiotechnologyInstitute, Akita Prefectural College of Agriculture, 2-2 Minami,Ohgata, Akita, 010-04 Japan ²Present address: Laboratory of Plant Molecular Biology, Schoolof Agricultural Sciences Nagoya University, Nagoya, 464-01 Japan     

Metabolism of p-Hydroxybenzoate via Hydroxyquinol by Trichosporon cutaneum WY2-2: Characterization of the Pathway using Superoxide Dismutase as a Stabilizer of Hydroxyquinol

Trichosporon cutaneum WY2-2 was shown to metabolize p-hydroxybenzoatevia protocatechuate and hydroxyquinol. Using superoxide dismutaseas a stabilizer of hydroxyquinol, the conversion of protocatechuateto hydroxyquinol and the ring fission process of hydroxyquinolwere confirmed. Hydroxyquinol was chemically identified as theproduct of protocatechuate hydroxylase reaction. Partially purifiedprotocatechuate hydroxylase was highly specific for protocatechuate;its K_m values for protocatechuate and NADH were 17.6 and 12.4µM, respectively. It catalyzed equimolar CO₂ formation,NADH oxidation and O₂ consumption from protocatechuate. Hydroxyquinoldioxygenase was highly specific for hydroxyquinol, with a K_mof 2.9 µM. ¹A preliminary account of this work was presented at the 81stMeeting of the Chubu-branch of Agricultural Chemical Societyof Japan, Gifu, October, 1980. ²Present address: Biological Institute, Faculty of Science,Nagoya University, Nagoya 464, Japan. ³Present address: Shin Nihon Chemical Co. Ltd... 19-10, Showa-cho,Anjoh, Aichi 446, Japan. (Received November 15, 1985; Accepted August 27, 1986)     

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; )     

Demonstration of light-induced potential change in Chara cells lacking tonoplast

Chara cells without tonoplasts, prepared by replacing the cellsap with EGTA-containing media, showed essentially the samepattern of light-induced changes in membrane potential and membraneresistance as normal cells although the concentrations of ionsand ATP in the cytoplasm decreased considerably (1/3–1/10)after loss of the tonoplast. Removal of the tonoplast reducedthe rate of photosynthetic O₂ evolution to about 50% of thatof normal cells but did not affect the magnitude of light-inducedpotential change. Not a full but a certain level of electronflow seems necessary to activate the putative electrogenic H⁺-pump. ¹ Present address: Department of Botany, Faculty of Science,University of Tokyo, Japan. ² Present address: Niigata College of Pharmacy, Niigata 950-21,Japan. (Received September 4, 1978; )     

Nitrite-reducing activity of modified cytochrome c-553 from the red alga Porphyra yezoensis Ueda

Crystalline cytochrome c-553 was obtained from Porphyra yezoensisUeda. The cytochrome in areduced form was modified to show anitrite-reducing activity after appropriate treatment with heat,hydrogen peroxide, or photooxidation using methylene blue asthe electron acceptor, but the reducing activity was far lowerthan that of the nitrite reductase isolated from this alga.The modified cytochrome c-553 was autooxidizable and showedan absorption spectrum resembling that of cytochrome c-553 inthe oxidized form except for slight shifts of the absorptionmaximumin the -band region toward shorter wavelengths. ¹ Present address: Department of Biological Sciences, Universityof Tsukuba, Sakura-Mura, Ibaraki, 300-31 Japan. ² Present address: Department of Fisheries, College of Agricultureand Veterinary Medicine, Nihon University, Shimouma, Setagaya-ku,Tokyo, 154 Japan. (Received June 10, 1975; )     

Characterization of a Maize Ca2+-Dependent Protein Kinase Phosphorylating Phosphoenolpyruvate Carboxylase

Phosphoenolpyruvate carboxylase (PEPC) [EC 4.1.1.31 [EC] ] of plantsundergoes regulatory phosphorylation in response to light ornutritional conditions. However, the nature of protein kinase(s)for this phosphorylation has not yet been fully elucidated.We separated a Ca²⁺-requiring protein kinase from Ca²⁺-independentone, both of which can phosphorylate maize leaf PEPC and characterizedthe former kinase after partial purification. Several linesof evidence indicated that the kinase is one of the characteristicCa²⁺-dependent but calmodulin-independent protein kinase (CDPK).Although the M_r, of native CDPK was estimated to be about 100kDa by gel permeation chromatography, in situ phosphorylationassay of CDPK in a SDS-polyacrylamide gel revealed that thesubunit has an M_r of about 50 kDa suggesting dimer formationor association with other protein(s). Several kinetic parameterswere also obtained using PEPC as a substrate. Although the CDPKshowed an ability of regulatory phosphorylation (Ser-15 in maizePEPC), no significant desensitization to feedback inhibitor,malate, could be observed presumably due to low extent of phosphorylation.The kinase was not specific to PEPC but phosphorylated a varietyof synthetic peptides. The possible physiological role of thiskinase was discussed. ¹Present address: NEOS Central Research Laboratory, 1-1 Ohike-machi,Kosei-cho, Shiga, 520-3213 Japan. ²Present address: Chugai Pharmaceutical Co., Ltd., 1-135 Komakado,Gotemba, 412-0038 Japan. ⁴N.O. and N.Y. contributed equally to this work.     

Novel Light-Dark Change of Proline Levels in Halophyte (Mesembryanthemum crystallinum L.) and Glycophytes (Hordeum vulgare L. and Triticum aestivum L.) Leaves and Roots under Salt Stress

Proline accumulation was determined in a facultative halophyte,Mesembryanthemum crystallinum and glycophytes, barley (Hordeumvulgare L.) and wheat (Triticum aestivum L.) Proline accumulationpreceded the shift of CAM in M. crystallinum and did not occurin the continuous darkness. The novel light-dark change of prolinelevel (high in the light and low in the dark) was observed inleaves of all three plants. Proline levels of shoots in barleyand wheat also showed the same light-dark change, suggestingthat proline accumulated in the leaves in the light was nottranslocated to other tissues in the dark period. These resultssuggest that proline has a bifunctional role in the acclimationto high salt stress; an osmoregulant role in the light, anda substrate for dark respiration to supply energy to compartmentationof ions into vacuole in the dark. ¹Present address: Kyoto Biological Res. Lab., Bio-Chiba Inc.Watsuka,Soraku, Kyoto, 619-12 Japan ²Present address: Kobayashi Pharmaceutical Co., Ltd. Doshomachi,Chuo-ku, Osaka, 541 Japan     

Light-Dependent Expression of Protochlorophyllide Oxidoreductase Gene in the Liverwort, Marchantia paleacea var. diptera

A cDNA encoding the NADPH:protochlorophyllide oxidoreductase(EC 1.6.99.1 [EC] ) was isolated from suspension-cultured cells ofthe liverwort, Marchantia paleacea var. diptera. In contrastto the situation in most higher plants, the liverwort gene wasexpressed in a light-dependent manner. ²Present address: Department of Biological Science, Facultyof Science, Kumamoto University, Kurokami, Kumamoto, 860-8555Japan.     

Separation and Partial Characterization of Membranes from Prochloron sp.

Two differently colored membrane preparations were separatedfrom the prochlorophyte, Prochloron sp., by mechanical disintegrationof the cells followed by sucrose density gradient centrifugation.An orange-colored preparation, containing zeaxanthin as themajor constituent pigment, seemed to comprise the cytoplasmicmembrane. The other green-colored membrane preparation, containingß-carotene and chlorophyll a and b as major pigmentconstituents, was identified as the thylakoid membrane. Thetwo types of membranes were compared as to their absorptionspectra and buoyant densities. ¹ This work is one of the results of the 8th International Expeditionon Prochloron organized by Dr. R. A. Lewin, University of Californiaat San Diego. ⁵ Present address: Solar Energy Research Group, The Algatron,The Institute of Physical and Chemical Research (RIKEN), Wako-shi,Saitama 351, Japan. ⁶ Present address: National Institute for Basic Biology, Okazaki444, Japan. (Received October 19, 1984; Accepted January 7, 1985)     

NO2 Suppression of Light-Induced Nitrate Reductase in Squash Cotyledons

NADH-nitrate reductase (NR) (EC 1.6.6.1 [EC] ) activity in the cotyledonsof squash (Cucurbita maxima Duch.) seedlings showed daily variationwhen the seedlings were subjected to an alternating light-darkcycle. When the seedlings were transferred into continuous darkness,NR activity rose at first and then decreased continuously. Irradiationafter continuous darkness induced a rapid increase in NR activity;this light induction of NR activity was inhibited completelyby fumigation with 4 ppm nitrogen dioxide (NO₂). This inhibitoryeffect of NO₂ was prominent even at 1 ppm and became more pronouncedas the concentration of NO₂ increased. NO₂ fumigation did notremarkably affect the content of reductant (NADH) in the cotyledons.The results of immunoblotting using anti-NR serum indicatedthat irradiation induced the increase in the NR-polypeptidecontent and NO₂ fumigation inhibited the increase, suggestingthat NO₂ put an inhibitory effect on the synthesis of NR inducedby irradiation. ⁴ Present address: College of Environmental Health, Azabu University,Fuchinobe, Sagamihara, Kanagawa 229, Japan ⁵ Present address: Faculty of Home Economics, Otuma Women'sUniversity, Sanban-cho, Chiyoda, Tokyo 102, Japan (Received October 21, 1987; Accepted January 13, 1988)     

High Affinity of the 5'-Upstream Region of a Winged Bean Chymotrypsin Inhibitor Gene for Nuclear Matrix

The 5'-upstream region of a winged bean chymotrypsin inhibitorgene (WCI-3b) was found to have a high affinity for nuclearmatrix. The region, named WCI-3b MAR (matrix attachment region),is highly A+T-rich and contains multiple sites interacting withnuclear matrix. A MAR was also found in the corresponding regionof the WCI-x gene, another active gene of the WCI family. SeveralMAR-binding proteins were detected in the wheat nuclear matrix. ⁴Present address: Friedrich Miescher Institute, P.O. Box 2543,CH-4002 Basel, Switzerland. ⁵Present address: Research Institute for Biological Sciences(RIBS), Kayo-cho, Jyobo-gun, Okayama, 716–1241 Japan.     

Effects of Exogenous Auxin on the Regulation of Elongation Growth of Excised Segments of Vigna Hypocotyls under Osmotic Stress

IAA applied simultaneously with osmotica greatly enhanced theadaptive recovery of the elongation growth of segments of Vignahypocotyls during osmotic stress irrespective of whether ornot absorbable solutes were present. IAA stimulated both thesurface pump and the xylem pump, which have been shown to bestimulated by osmotic stress and to control the yielding ofthe cell wall and the absorption of solutes. Thus, wall extensibilityand the effective turgor were further enhanced under osmoticstress in the presence of IAA. These results indicate that thesimultaneous presence of IAA can reduce the inhibition of growthby osmotic stress, and they support numerical predictions basedon the apoplast canal model. The mechanism involved in the rapidrecovery of growth is discussed. ¹ Present address: Research Centre, Guangxi Agricultural University,Xiu Ling Rd., Nanning, Guangxi 530005 China. ² Present address: Biology Institute, Department of GeneralEducation, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya,464 Japan. ³ Present address: Graduate School of Integrated Science, YokohamaCity University, 22-2, Seto, Kanazawa-ku, Yokohama, 236 Japan.     

Studies on anaerobic biphasic growth of a denitrifying bacterium, Pseudomonas stutzeri

Growth of Pseudomonas stutzeri(VAN NIEL strain) in the presenceof a limiting amount of nitrate under anaerobic conditions ischaracterized by 2 logarithmic phases separated distinctly byan intermediate phase where the growth rate is very low. Inthe first logarithmic phase nitrate is reduced stoichiometricallyto nitrite stage, and in the second phase nitrite is reducedto nitrogen gas. The nitrite reducing activity of cells in the second growthphase is 3–4 times higher than that of cells in the firstphase. The rise in nitrite reducing activity is correlated witha remarkable increase in the content of cytochromes a₂ and c-552. ¹Present address: Department of Biochemistry, Hiroshima UniversitySchool of Dentistry, Hiroshima, Japan. ²Present address: Institute of Molecular Biology, Faculty ofScience, Nagoya University, Nagoya, Japan. (Received June 16, 1969; )     

Molecular Cloning and Characterization of S-Adenosyl-L-Methionine:Scoulerine-9-O-Methyltransferase from Cultured Cells of Coptis japonica

S-Adenosyl-L-methionine : scoulerine-9-O-methyltransferase (SMT)catalyzes the transfer of the S-methyl group of S-adenosyl-L-methionineto the 9-hydroxyl group of scoulerine during the biosynthesisof berberine. We have isolated functionally active cDNA clones(pCJSMTs) from a cDNA library prepared from cultured cells ofCoptis japonica. The longest cDNA insert (pCJSMT1) had an openreading frame that encoded 351 amino acids, but the calculatedmolecular mass (38,364 Da) of the deduced product was slightlylower than the experimentally determined molecular mass of purifiedSMT. Rapid amplification of the 5' end of the cDNA indicatedthat the full-length cDNA of SMT consisted of 1,458 nucleotidesthat encoded 381 amino acids. When the full-length cDNA wasexpressed in E. coli, the molecular mass of the expressed SMTwas greater than that of native SMT in Coptis cells. This resultsuggests that SMT might be produced in a pre-mature form andprocessed post-translationally. SMT was also found to exhibitsequence homology to other O-methyltransferases from plantsand N-terminal region of the SMT polypeptide appeared to benecessary for enzymatic activity. ¹Present address: High Quality Life Research Laboratories, SumitomoMetal Industries, Ltd., 3-5 Hikaridai, Seika, Sourakugun, Kyoto,619-02 Japan ²Present address: Suntory Research Center, 1-1-1 Wakayamadai,Shimamoto, Mishima-gun, Osaka, 618 Japan ³Present address: Department of Cell Biology, The Scripps ResearchInstitute, La Jolla, CA 92037 U.S.A.