Boron Nutrition of Cultured Tobacco BY-2 Cells. II. Characterization of the Boron-Polysaccharide Complex

In cultured tobacco BY-2 cells, more than 90% of the cellularboron (B) occurs in the cell wall and a negligible amount ofB is detected in the membrane fraction. Nearly 80% of the cellwall B binds to rhamnogalacturonan II (RG-II) to form a borate-dimericRG-II complex. Mono-meric RG-II is not detected in the cellwall, but it is detected in the extracellular polysaccharides.The complex is reconstituted spontaneously in vitro simply bymixing mon-omeric RG-II and boric acid at pH 4. Germanic acid,which partially substitutes for B in the growth of the B-deprivedplants, also induces dimerization of RG-II. These results suggeststhat B may fulfill its essential function as forming the B-RG-IIcomplex in cell walls. ¹ Present address: Kasai Experimental Farm, Sumitomo ChemicalCo., Ltd., Kasai, Hyogo, 675%ndash;23 Japan     

Distribution of Calcium and Boron in the Pectin Fraction of Tomato Leaf Cell Wall

Calcium was present in the pectin fraction of tomato leaf cellwall in association with pectin constituents and with a pectin-proteincomplex. Boron deficiency induced a decrease in the amount ofCa associated with pectin constituents. Most of the boron inthe pectin fraction obtained by pectinase treatment was in afree form. These results suggest that boron plays an importantrole in Ca metabolism in the cell wall. ¹Present address: Institute of Applied Biochemistry, Yagi MemorialPark, Mitake, Gifu, Japan. (Received July 31, 1985; Accepted February 18, 1986)     

Effects of Cerebroside and Cholesterol on the Reconstitution of Tonoplast H+-ATPase Purified from Mung Bean (Vigna radiata L.) Hypocotyls in Liposomes

For an examination of the effects of cholesterol and cerebrosideon the rate and extent of proton-pumping across the membranesof proteoliposomes prepared with tonoplast H⁺-ATPase, the tonoplastH⁺-ATPase of mung bean (Vigna radiata L.) was purified by fastprotein liquid chromatography (FPLC) and incorporated into liposomesprepared from asolectin and cholesterol or cerebroside. Proteoliposomeswere formed after the removal of Triton X-100 from a mixtureof Triton X-100, asolectin and purified tonoplast H⁺-ATPaseby passage through an Ampure DT column. Proteoliposomes preparedfrom cholesterol and asolectin at a ratio of 45 : 55 (w/w) andat a ratio of lipid to protein of 200 : 1 (w/w) gave the largestpH gradient, as determined by the ATP-generated quenching ofquinacrine fluorescence. In the presence of cholesterol, thepH gradient formed across the membranes of proteoliposomes andthe average diameter of proteoliposomes increased about two-fold.The initial rate of proton-pumping decreased to 20% of thatobserved with proteoliposomes prepared from asolectin alone.The addition of cerebroside to asolectin at a ratio of 5 : 95(w/w) caused a 1.6-fold increase in the maximum pH gradientwithout any significant change in the initial rate of proton-pumpingor the diameter of proteoliposomes, but the maximum pH gradientdecreased greatly at ratios above 20 : 80 (w/w). The maximumpH gradient was transient and decreased spontaneously when onlyasolectin was used to prepare proteoliposomes, or when cerebrosideand asolectin were used together. Disappearance of the protongradient once it had formed and/or leakage of protons were suppressedby cholesterol at ratios above 30 : 70 (w/w). It was clear,therefore, that cholesterol and asolectin at ratios 30 : 70(w/w) to 45 : 55 (w/w) formed larger and more stable proteoliposomesthan did asolectin alone. ¹Present address: Laboratory of Climatic Stress Control, TohokuNational Agricultural Experiment Station, 4 Shimokuriyagawa,Morioka, Iwate, 020-01 Japan     

A Method for the Rapid Growth in Culture of Gametophytes of Equisetum arvense with Antheridia

Rapid growth in culture of Equisetum arvense gametophytes wasobtained using Murashige-Skoog's medium plus 3% (w/v) sucroseand continuous illumination. In darkness, growth was reducedand chlorophyll synthesis markedly inhibited. Antheridia formedon the top margin of gametophytes in light and darkness butarchegonia were not observed in either case. ¹Present address: Interdisciplinary Research Institute of EnvironmentalSciences, Higashi-yanagi-cho, Nishi-iru, Shichihon-matsu, Itsutsuji-dori,Kamigyo-ku, Kyoto, 602 Japan. (Received June 5, 1989; Accepted September 12, 1989)     

Pharmacological and biophysical isolation of K+ currents encoded by ether-à-go-go-related genes in murine hepatic portal vein smooth muscle cells

The functional properties of the Saccharomyces cerevisiae bicarbonate transporter homolog Bor1p (YNL275wp) were characterized by measuring boron (H₃BO₃), Na⁺, and Cl^– fluxes. Neither Na⁺ nor Cl^– appears to be a transported substrate for Bor1p. Uphill efflux of boron mediated by Bor1p was demonstrated directly by loading cells with boron and resuspending in a low-boron medium. Cells with intact BOR1, but not the deletant strain, transport boron outward until the intracellular concentration is sevenfold lower than that in the medium. Boron efflux through Bor1p is a saturable function of intracellular boron (apparent K_m 1–2 mM). The extracellular pH dependences of boron distribution and efflux indicate that uphill efflux is driven by the inward H⁺ gradient. Addition of 30 mM HCO₃^– does not affect boron extrusion by Bor1p, indicating that HCO₃^– does not participate in Bor1p function. Functional Bor1p is present in cells grown in medium with no added boron, and overnight growth in 10 mM H₃BO₃ causes only a small increase in the levels of functional Bor1p and in BOR1 mRNA. The fact that Bor1p is expressed when there is no need for boron extrusion and is not strongly induced in the presence of growth-inhibitory boron concentrations is surprising if the main physiological function of yeast Bor1p is boron efflux. A possible role in vacuolar dynamics for Bor1p was recently reported by Decker and Wickner (10). Under the conditions used presently, there appears to be mildly abnormal vacuolar morphology in the deletant strain. boron; SLC4; YNL275w     

Analogues of Phenoxyacetic Acid and the Generation of Calluses from Seeds of Indica Rice

In a search for callus-inducing compounds for indica rice thatare superior in this regard to 2,4-dichlorophenoxyacetic acid(2,4-D), we tested 13 derivatives of phenoxyacetic acids, namely,mono- and di- chloro-, mononitro- and 4-halogeno-substitutedphenoxyacetic acids for their ability to stimulate the inductionof calluses from mature seeds of rice (Oryza sativa L. cv. Chiemchanh). Five analogues of benzoic acid were also tested. Thecallus-forming ability and the optimal concentration for inductionof calluses were differed from compound to compound. The optimal concentration for callus induction of 4-fluorophenoxyaceticacid (4FPA) was relatively high (250 µM), but its callus-formingactivity was stronger than that of 2,4-D, even when comparedwith 2,4-D at its optimal concentration (50 µM). 4FPA-inducedcalluses retained their regenerative ability for at least 15months with 9 subcultures, while calluses induced by 2,4-D losttheir regenerative ability after 3 subcultures. 4FPA-induced calluses showed higher regenerative ability thandid calluses induced by 2,4-D, in almost all of 20 varietiesof indica tested, including three indica-japonica hybrids. ³Present address: Kibun Co.Ltd., Ginza, Tokyo, 104 Japan ⁴Present address: Hyogo Agricultural Research Institute, Kasai,Hyogo, 679-01 Japan (Received October 25, 1989; Accepted May 17, 1990)     

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     

Effect of environmental factors on water utilization and boron accumulation and translocation in sugarcane

Rates of boron (B) accumulation and/or water utilization of3 month-old sugarcane plants were altered by changes in temperature,relative humidity, light intensity and duration of exposureto light. The effects of the environment on boron accumulationwere not directly dependent upon effects on water utilization.Boron accumulation was affected more than water uptake by increasingroot and air temperatures from 8°C to 37°C, and by raisingthe pH of the external solution from 5.7 to 7.0. Contrarily,water utilization decreased more than B accumulation when therelative humidity was increased from 30±5% to 95±5%,when light intensity was decreased or daily exposure to lightwas shortened and when the plants were pretreated with 5x10^–5M phenyl mercuric acetate, an anti-transpirant. The absorption of B by roots was experimentally separated fromits subsequent translocation to the shoots. Absorption of Bby roots was at least partially under metabolic control, sinceuptake from a 2 mg/liter B solution could occur against a concentrationgradient. Translocation of B from the roots to the shoot occurredpassively in the transpiration stream. ¹ Journal Series No. 1427 of the Hawaii Agricultural ExperimentStation. (Received March 2, 1972; )     

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; )     

Bimodal (Taste/Tactile) Fibers Innervate the Maxillary Barbel in the Channel Catfish

Analysis of single fibers isolated from a branch of the facial/trigeminalcomplex innervating the maxillary barbel of the channel catfish,Ictalurus punctatus, indicated the existence of bimodal (taste/tactile)fibers. Of the 60 single fibers recorded, 14 (23%) respondedto both taste (amino acid) and tactile stimulation, 43 (72%)were responsive to only tactile stimulation and three (5%) respondedonly to taste stimulation. Quinine hydrochloride at a concentrationof 1.0 mM suppressed the mechanosensory activity of the bimodalfibers, but had no effect on the tactile-only fibers. Chem.Senses 22: 477–482, 1997. ¹Current address: Department of Otolaryngology, Kagoshima UniversityMedical School, 8-35-1 Sakuragaoka, Kagoshima 890, Japan ²Current address: Department of Oral Physiology, Ohu UniversitySchool of Detistry, 31-1 Misumido, Tomita, Koriyama, Fukushima963, Japan     

Effect of abscisic acid and auxin on ribonuclease during ageing of bean endocarp tissue sections

The activity of RNase increases rapidly upon cutting sectionsof bean (Phascolus vulgaris L. var. Kentucky Wonder) endocarp,peaks within 4 to 8 hr and then declines. This rapid developmentof RNase activity is inhibited by cycloheximide. Auxin (naphthaleneaceticacid, NAA) accelerates the rate of decline of RNase. Abscisicacid (ABA) enhances the level of RNase between 4 and 24 hr,associated with a decline in RNA, and this effect of ABA isobscured in the presence of auxin. ¹ This work was supported by National Science Foundation Grant(GB-8316) to J. A. Sacher. ² On leave from Laboratorio di Radiobiochimica ed EcofisiologiaVegetale, C. N. R., Roma, (Italy), with a Fellowship supportedby North Atlantic Threaty Organization. ³ Present address: Instituto di Botanica, Universita di Ban,Bari, 70126, Italy. (Received April 1, 1971; )     

Properties of the Respiratory NAD(P)H Dehydrogenase Isolated from the Cyanobacterium Synechocystis PCC6803

Activity staining with NADPH-nitroblue tetrazolium after native-PAGEof membrane proteins of Synechocystis PCC6803, solubilized with3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS),revealed four NAD(P)H dehydrogenase (NDH) activities; an NDHcomplex of the respiratory chain, a ferredoxin NADP⁺ reductase(FNR), a drgA product which oxidized both NADH and NADPH, andan uncharacterized NADH-specific enzyme. The NDH complex waspurified with anion exchange and gel filtration chromatographies.The purified complex had a molecular mass of 376 kDa and wascomposed of 9 subunits. Western analysis showed that the complexcontained the NDH-H subunit, but not NDH-A or B. The enzymereduced ferricyanide much faster than plastoquinone and usedNADPH as its prefered electron donor rather than NADH. The enzymaticactivity was inhibited by diphenyleneiodonium chloride and salicylhydroxamicacid, but not by rotenone, p-chloromercuribenzoate, N-ethylmaleimide,flavon, dicumarol, or antimycin A. These results suggest thatthe purified complex is a hydrophilic subcomplex which containsan NADPH binding site and flavin, and is dissociated from ahydrophobic subcomplex, which contains quinone binding site. ¹Present address: Division of Applied Life Sciences, GraduateSchool of Agriculture, Kyoto University, Sakyo, Kyoto, 606-8502Japan ³Present address: Department of Biotechnology, Faculty of Engineering,Fukuyama University, 1 Gakuencho, Fukuyama, Hiroshima, 729-0292Japan     

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.     

Experimental evaluation of the avoidance reaction of Calanus finmarchicus

The avoidance reaction of Calanus finmarchicus copepodids wasobserved in the presence of quantifiable fluid mechanical signals.The experimental apparatus was a rotating cylinder of sea waterwith fixed obstacles (diameters 6 mm and 10 mm) which disturbedthe flow and stimulated avoidance. The experimental conditionsprevented unambiguous discrimination of signals; the amountand rate of fluid deformation appear to be the effective stimuli.Avoidance reactions began at a mean distance of 7 mm from thesmall obstacle and 6 mm from the large obstacle. Mean valuesfor fluid deformation for the small and large obstacles were0.12 and 0.24 mm/mm; fluid deformation rate values were 0.80and 1.0 sec^–1. There was less scatter for deformationvalues. The copepods preferentially avoided obstacles at anglesof about 60° with respect to the approach streamline. Avoidancespeeds averaged 16 cm.sec^–1; mean distance of avoidanceflights was 15 mm. ¹Contribution Number 4195 from the Woods Hole OceanographicInstitution. ²Present Address: Scripps Institution of Oceanography, La Jolla,California 92093. ³Present Address: Marathon Oil Company, Littleton, Colorado80160.     

Changes in soluble proteins in potato leaves infected with Phytophthora infestans

A new protein was observed in the electrophoretic gel band ofleaves of cultivar susceptible to Phytophthora infestans, whenthe DNA fraction of a resistant hybrid was applied to the leaves.The Rf value of this band coincided with that of the hybrid6 hr after die inoculation of a race of P. infestans to whichit was resistant. ¹Present adress: Laboratory of Plant Pathology, College of Agriculture.Kyoto University, Kyoto, 606) Japan. ²His former family name was Nakao. (Received December 19, 1975; )     

COMPARATIVE STUDIES ON GROWTH, RESPIRATION, PHOTOSYNTHESIS AND PIGMENT CONTENT IN RHODOPSEUDOMONAS PALUSTRIS

1. Comparative studies were performed on growth, photosyntheticand respiratory activities, and pigment content in Rhodopseudomonaspalustris.
2. The growth of the organism, as influenced by variousculturalconditions such as light, aerobiosis, anaerobiosisand nutritionalfactors was investigated.
3. The respiratoryactivity of the bacterium was found to be higherin dark-growncells than in cells grown in the light. The photosyntheticactivitydid not significantly depend on the growth conditionsof theculture. Cells of younger cultures were found to be moreactivethan those of older cultures, with respect both to respirationand photosynthesis.
4. The pigment content was found to be higherin the light-growncells than in the dark-grown ones. The ratiophotosyntheticactivity/bacteriochlorophyll was significantlyhigher in thelatter than in the former.
5. Light, as well asvarious nutritional factors, was found toexert a marked accelerationon pigment formation, although ithas not yet been possibleto culture cells completely lackingin photosynthetic pigmentsand accordingly in photosyntheticactivity.

¹ Present address: Division of Dermatology and Urology, TokyoMetropolitan Hiroo Hospital, Tokyo. ² Present address: Department of Biology, Saitama University,Urawa. ³ Present address: Department of Biochemistry, School of Medicine,Yokohama University, Yokohama. ⁴ Present address: Department of Biophysics and Biochemistry,Faculty of Science, University of Tokyo, Tokyo. (Received July 23, 1961; )     

Purification and some properties of the membrane-bound hydroxyproline-containing glycoprotein from tobacco cells cultured in suspension

Membrane-bound hydroxyproline-containing glycoprotein from culturedtobacco cells was solubilized with chloroform. The glycoproteinwas homogeneous on acryl-amide gel electrophoresis and in ultracentrifugationanalysis. The glycoprotein was composed of 74% carbohydrateand 26% protein, and the carbohydrate moiety was composed ofgalactose, arabinose and rhamnose. The S₂₀ w value of the glycoproteinwas 5.4. ¹Department of Biochemistry, University of Texas Health ScienceCenter, San Antonio, Texas 78284, U.S.A. (Received December 15, 1979; )     

Optical emission spectrographic studies on the distribution and accumulation of nanogram amounts of 15N in rice seedlings

An optical emission spectrographic method was used to studythe distribution and accumulation of nanogram quantities of¹⁵N in leaves and roots of individual rice plants. Gaseous nitrogenthat was prepared from plant samples, not weighing more than100 µg, was trapped in an electrodeless tube. The excess¹⁵N was determined by exciting the gas with a high frequencygenerator, then measuring the light intensities of the molecularbandheads at 2977, 2983 and 2989 ?. For leaves that contained4 atom % ¹⁵N the precision obtained was ?1.33%. A comparisonof emission and mass spectrographic ¹⁵N values were obtainedwith a number of second leaves of rice plants that were grownunder similar environmental conditions. The ¹⁵N contents obtainedat a 2 atom % level by the 2 methods were in reasonable agreement. ¹Permanent address: University of Tokyo, Dept. of Agr. Chem.,Japan. ²Permanent address: Argonne National Lab., Argonne, Illinois,U. S. A. (Received April 2, 1969; )     

Effects of Manipulations of Source and Sink on the Carbon Exchange Rate and Some Enzymes of Sucrose Metabolism in Leaves of Soybean [Glycine max (L.) Merr.]

Soybean plants [Glycine max (L.) Merr. cv. AGS129], two andthree weeks after depodding and defoliation, respectively, wereused to examine the possibility of end-product regulation onthe carbon exchange rate and activities of enzymes involvedin sucrose metabolism in leaves. Removal of one and two lateralleaflets per trifoliate leaf reduced the total leaf area by20% and 47%, respectively. Removal of one pod per node reducedthe total pod number by 23% per plant. Dry weights of roots,stems and petioles decreased with reductions in leaf area. Bycontrast, removal of pods resulted in an increase in these parameters.The carbon exchange rate and transpiration rate of leaves increasedwith defoliation and decreased with depodding. The intercellularconcentration of CO₂ in leaves was reduced by defoliation andincreased by depodding. Furthermore, defoliation increased thelevel of leaf chlorophyll in leaves while depodding decreasedit. Removal of pods decreased the activities of sucrose-phosphatesynthase and -amylase but increased that of sucrose synthase.A significant positive correlation was found between the activityof leaf sucrose-phosphate synthase and both the carbon exchangerate and the sucrose content of leaves. Thus, manipulation ofthe sink and source in soybean plants influenced the relationshipbetween sucrose metabolism and the carbon exchange rate in intactleaves. ³Faculty of Agriculture, Okayama University, Tsusimanaka Okayama,700 Japan ⁴Faculty of Agriculture, Saga University, Honjo-machi, Saga,840 Japan ¹Present address: Faculty of Agriculture, Sriwijaya University,J1 Raya Indralaya, OK1 30662, Indonesia ²Present address: Faculty of Agriculture, Saga University, Honjo-machi,Saga, 840 Japan     

Properties of the Dicyclohexylcarbodiimide-Binding Subunit of Cytochrome c Oxidase from Sweet Potato

Subunit IV of cytochrome c oxidase from sweet potato was boundwith dicyclohexylcarbodiimide and synthesized in isolated mitochondria.Thus, this subunit corresponds to subunit HI of the analogousmammalian and fungal enzymes. Subunit IV was a mixture of twopolypeptides (subunits IVa and IVb) which differed slightlyin structure. ¹Present address: Research Institute of Molecular Genetics,Shimane University, Matsue, 690 Japan. ²Present address: Institute of Low Temperature Science, HokkaidoUniversity, Sapporo, 060 Japan.