Swelling of spinach chloroplasts induced by HCHO and KMnO4, an effect partially hidden by the wide size range of chloroplasts

Both KMnO₄ and HCHO in concentrations used for fixation forelectron microscopy induce pronounced swelling of spinach chloroplasts.However, since electron microscopy samples small numbers, itis possible to overlook the swelling effect because the sizerange of the swollen chloroplasts can overlap the extremelywide range of chloroplasts in living mesophyll cells. HCHO fixesspinach chloroplasts only after 16 hr incubation, as verifiedby failure of the chloroplaststo swell when subsequently washedwith water. However, the HCHO treatment fails to prevent aninitial swelling and KMnO₄ further swells chloroplasts pre-fixedwith HCHO. Spinach chloroplasts in vivo measured in face area27.7 0.06 µ² mean value, 23.8 µ² mode value, range6.2 to 102.9 µ², and their distribution is skewed so thatthe coefficient of skewness is 0.15. Chloroplasts isolated directlyinto phosphate buffered 4% HCHO after 24 hrs measured in facearea 58.2 µ² mean value, 46.5 µ² mode value, range22 to 121 µ², and the coefficient of skewness increasedto 0.24. When such chloroplasts were additionally treated withphosphate buffered 2.8 % KMnO₄ the spinach chloroplasts measuredin facearea 96.4 1.40 µ² mean value, 86.1 µ² modevalue, range22 to 203 µ², and the coefficient of skewnessunchanged at 0.24. Volumes of spinach chloroplasts isolatedin NaCl as reported in the literature approach the volumes ofchloroplasts swollen by HCHO and KMnO₄. Some problems concerningsampling difficulties because of wide size ranges and skeweddistributions are discussed. ¹ Present address: Department of Agriculture, Bangkhen ExperimentStation, Bangkok, Thailand. ² Present address: Department of Biology, Wright State University,Dayton, Ohio 45431 U.S.A.     

Identification of the Excitable Cells in the Petiole of Mimosa pudica by Intracellular Injection of Procion Yellow

Excitable cells in the petiole of Mimosa pudica were locatedby microelectrode technique and stained with Procion YellowMx4R which was previously filled in the electrode and injectediontophoretically into the cells. Microscopic observations ofsections of the stained petioles revealed that protoxylem parenchymacells and narrow phloem cells were excitable. The protoxylemlocalized just inside the metaxylem was composed almost entirelyof the parenchyma cells which were 106.3±5.2 µmlong (mean±EM, n=15) and 14.2±0.6 µm indiameter (n =33). The excitable phloem cells were 76.4±4.1µm long (n=7) and 7.0±0.3 pan in diameter (n=37)and were thought to be companion cells or narrow parenchymacells or both. Amplitudes of action potentials recorded fromthe petiolar surface had a linear relation to those from theexcitable cells in the same petiole. From this fact and thearrangement of excitable cells in the petiole, we conclude thatwhen the transmission of action potential takes place in thepetiole all excitable cells in it are activated. ¹ Present address: 1st Department of Physiology, Hamamatsu UniversitySchool of Medicine, Handa-cho 3600, Hamamatsu 431-31, Japan. (Received September 7, 1982; Accepted November 8, 1982)     

BIOTIN LIBERATION BY THE LICHEN ALGA COCCOMYXA SP. AND BY CHLORELLA PYRENOIDOSA

The unicellular green alga Coccomyxa, a component of the lichenPeltigera aphthosa, liberated about 7.2mµg biotin permg dry weight of cells into the culture medium during a growthperiod of 15–20 days. The corresponding figure for thefree-living alga Chlorella pyrenoidosa was 0.45mµg ofbiotin. Chromatographic analysis indicated that this was freebiotin and not a bound form of the vitamin. The biotin concentrationof rinsed Coccomyxa cells was 1.88mµg per mg dry weightof cells, of which less than 0.01mµg was extractable byhot water. Cells of Chlorella contained 0.16mµg of biotinper mg dry weight, of which 0.11mµg was extractable byhot water. The biotin content of Coccomyxa, which was about12 times that of Chlorella, is thus almost entirely in the boundform. The importance of biotin in the symbiotic interactionsbetween the alga and the fungus in Peltigera is discussed. ¹Present address: University Department of Agriculture, Oxford,England. ²Present address: Institute of Marine Resources, Universityof California, La Jolla, California, U.S.A.     

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)     

A HISTOLOGICAL SURVEY OF GONADAL DEVELOPMENT IN ARION ATER L. (MOLLUSCA, PULMONATA)

A method of breeding the slug Arion ater L. in the laboratorywas established. Measurements were made at monthly intervalsof body weight, weight and volume of the hermaphrodite gland,diameter and number of acini, oocytes and other cell types insidethe acini in field and laboratory-reared animals. Male and femalegametes grow simultaneously in the hermaphrodite gland of fieldanimals during the year. High humidity and low temperature causedinhibition of spermatogenesis and increase in the number offemale gametes in laboratory-reared animals. The average rateof increase in diameter of the oocytes of field samples was10 µm per month and in laboratory samples 9 µm permonth. ^*Present address: Department of Biology, School of Sciences,Ferdowsi University, Mashhad, Iran. (Received 30 September 1977;     

Properties of S-adenosyl-L-methionine-magnesium-protoporphyrin IX methyltransferase from barley

S-Adenosyl-L-methionine-magnesium-protoporphyrin IX methyltransferase(EC 2.1.1.11 [EC] ) is present in greening barley seedlings associatedwith the particulate fraction. This enzyme was purified 20 foldusing protamine and ammonium sulfate precipitation. The enzymewas active over a wide pH range with highest activity at pH7.5. The Km values for Mg-protoporphyrin IX and S-adenosylmethioninewere 48 and 39 µM, respectively; S-adenosylethionine andS-adenosyihomocysteine were competitive inhibitors with respectto S-adenosylmethionine; hemin inhibition was non-competitivewith respect to Mg-protoporphyrin IX; thiol compounds exhibiteda stimulatory effect on enzyme activity. The properties of theenzyme are discussed and compared with the enzyme from otherorganisms. ¹ This research was supported in part by the Utah State AgriculturalExperiment Station. ² Present address: Department of Chemistry, Boston University,Boston, Massachusetts, U. S. A. ³ Present address: Department of Biochemistry and Microbiology,Faculty of Pharmacy, Comenius University, Bratislava, Czechoslovakia. (Received February 20, 1978; )     

Phototropic sensitivity in Vaucheria geminata regulated by 3',5'-cyclic AMP

Exogenous 3',5'-cyclic AMP in physiological concentrations inhibitsthe phototropic bending of Vaucheria geminata without affectinggrowth. Related substances known to change the intracellularcyclic AMP level also alter phototropic sensitivity. This indicatesthat the steering process (i.e., initial phototropic response)is separate from growth itself. Cyclic AMP extracted from this alga amounted to 0.2–0.3nmole per g fresh weight, or about 3 µM on a cytoplasmvolume basis. This value coincides with expected results fromexperiments with exogenous cyclic AMP. The results suggest thatendogenous cyclic AMP may play an essential role in the gain-controllingprocess of phototropism. ¹ Present address: Institute for Agricultural Research, TohokuUniversity, Sendai 980, Japan. (Received November 26, 1976; )     

Tentoxin Inhibits Both Photophosphorylation in Thylakoids and the ATPase Activity of Isolated Coupling Factor F1 from the Cyanobacterium Anacystis nidulans

Tentoxin strongly inhibited the ATPase activity of isolatedcoupling factor 1 (AF₁) from the cyanobacterium Anacystis nidulans,with 50% inhibition occurring at 0.3 µM. When thylakoidsfrom A. nidulans were preincubated with 0.3 µM tentoxinfor 30 min, photophosphorylation was inhibited by 50%. Measurementsof fluorescence from 9-aminoacridine indicated that tentoxininhibited the utilization of the proton gradient by ATP formationin thylakoids. These results indicate that tentoxin is a strongenergy-transfer inhibitor of photophosphorylation in A. nidulans.Tentoxin decreased the level of ATP in intact cells both inthe light and in darkness, its effects being much stronger inthe dark. Tentoxin at 50 µM strongly inhibited the growthof the cells. ³Present address: Corporate Research and Development Laboratory,Tonen Co. 1-3-1 Nishi-tsurugaoka, Ohi-machi, Saitama, 354 Japan ⁴Present address: Technology and Engineering Laboratories, AjinomotoCo., Inc. Suzuki-cho 1, Kawasaki, 210 Japan     

Photosynthesis-Dependent Volume Regulation in Guard Cell Protoplasts from Vicia faba L.

A rapid and convenient procedure was developed for isolatingguard cell protoplasts (GCPs) from epidermal strips of Viciafaba L. The mean rates of O₂ uptake in the dark and evolutionin light of the isolated GCPs were 200 and 290 µmol O₂mg^–1 Chl h^–1, respectively, showing net O₂ evolutionin light. Photosynthetic O₂ evolution was suppressed completelyby 5 µM DCMU. Addition of 5 µM DCMU to the incubationmedium after 30 min of light exposure also suppressed the light-inducedswelling of GCP, indicating possible participation of PS IIin volume regulation in GCP. ⁴Present address: Division of Environmental Biology, The NationalInstitute for Environmental Studies, Yatabe machi, Tsukuba,Ibaraki 305, Japan. (Received December 17, 1983; Accepted March 21, 1984)     

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; )     

An Alternative Electron Transfer Pathway Mediated by Chloroplast Envelope

Localization of redox active substance(s) in chloroplast envelopeswas revealed by means of the oxidation of Cyt c by isolatedouter and inner envelope preparations. Irradiated chloroplastsreduced extra-chloroplastic Cyt c probably by an envelope electrontransfer chain. The rate was saturated at a level of about 10µmol (mg Chl)^–1 h^–1 under weak light of 10µEm^–2 s^–1. Cyt c photoreduction was inhibited by DCMUbut not by 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB)indicating that the plastoquinone site is the junction of photosyntheticelectron transfer chain to envelope redox substance. Completesuppression of the non-cyclic photophosphorylation of thylakoidsby the presence of envelope membranes indicates that there isan alternative electron transfer path-way in envelope membranesthat bypasses over the pH-forming plastoquinone shuttle in thephotosynthetic electron transfer chain. ¹ Present address: Photosynthesis Research Laboratory, Instituteof Physical and Chemical Research (RIKEN), Wako, Saitama, 351-0198Japan.     

Analysis of abscission responses to photodecomposition products of 1-naphthaleneacetic acid

This paper presents an analysis of abscission reponses of cottonexplants to (a) 1-naphthaneneacetic acid; (b) photodecompositionproducts of 1-naphthaleneacetic acid: 1-methylnaphthalene, 1-naphthaldehyde,1-naphthoic acid, naphthalene, and phthalic acid; and (c) arelated compound: naphthaleneacetyl aspartate. Abscission wasaccelerated by low amounts and retarded by high amounts of 1-naphthaleneaceticacid and 1-naphthoic acid. No significant effect on abscissionwas observed from 1- methylnaphthalene, 1-naphthaldehyde, orphthalic acid applied in amounts from 10^–8 to 10.0 µgper petiole; or with naphthalene from 10^–3 to 10.0µgper petiole. Naphthaleneacetyl aspartate had no effect at 5?10⁴to 5?10^–3 µg per petiole, but completely inhibitedabscission at 5 ? 10^–1 and 5.0 µg per petiole. Thedata are analyzed on part by a previously described mechanicalmethod for the determination of abscission indexes, and in partby a new method described herein, using a digital computer forthe analysis of the abscission time-course data. The resultshave significance to the understanding of the variability encounteredin fruit thinning by 1-naphthaleneacetic acid and related substances,and are discussed in relation to the known intermediate effectsof 1-naphthaleneacetic acid in fruit thinning. ¹Present address: Department of Biology, Univesity of California,Riverside, California 92502, U.S.A. (Received August 26, 1972; )     

Amarinin: A New Growth Inhibitor from Luffa amara

A growth inhibitor, amarinin was isolated from the seeds ofLuffa amara. Its formula has been established as 2-deoxy cucurbitacinB by spectrometric analysis coupled with chemical degradation.Amarinin inhibited the growth of the second leaf sheath of riceboth in the absence and presence of GA₃. ¹Present address: Department of Chemistry, Arambag College,P.O. Arambag, Hooghly, West Bengal, India ²Present address: Department of Chemistry, Calcutta University,92, A.P.C. Road, Calcutta 700 009 (Received March 15, 1985; Accepted May 1, 1986)     

Occurrence of dinoflagellate Alexandrium tamarense, a causative organism of paralytic shellfish poisoning in Chinhae Bay, Korea

A paralytic shellfish poisoning (PSP) incident caused by consumptionof the mussel Mytilus edulis occurred for the first time inKorea in April 1986. Weekly water samplings were carried Outduring the period from 7 March to 21 April 1989 in Chinhae Bay,Korea, in order to identify the causative organism. The temperaturecharacteristics of the water column indicated three differenthydrological regimes: well mixed (up to 7 March), weakly stratified(17–31 March) and stratified (7–21 April). Toxicityof the phytoplankton was detected during the weakly stratifiedperiod, but only in the 10–50 p.m phytoplankton size fraction.This study presents the occurrence of the toxigenic dinoflagellateAlexandrium tamarense, which is a causative organism of PSP,in Korean coastal waters. Its biomass varied at different depthsin the water column, ranging from 200 to 8000 cells 1^–1in the water column. The weekly fluctuation of A.tamarense toxicitywas similar to that of mussel toxicity. ¹ Present address: Department of Biology, College of NaturalSciences, Hanyang University, Seoul 133-791, Korea     

Effects of Deoxygibberellin C (DGC) and 16-Deoxo-DGC on Gibberellin 3{beta}-Hydroxylase and Plant Growth

Deoxygibberellin C (DGC), a C/D ring-rearranged isomer of GA₂₀,was shown to inhibit the conversion of [2,3-³H₂]GA₉ to [2-³H]GA₄by gibberellin 3ß-hydroxylase from immature seedsof Phaseolus vulgahs. Deoxygibberellin C inhibited the promotionof growth by exogenously applied GA₂₀ of rice (Oryza sativaL.) seedlings. Evidence is also presented that DGC is a competitiveinhibitor of the 3ß-hydroxylase from P. vulgaris.However, DGC only weakly inhibited the conversion catalyzedby the 3ß-hydroxylase from Cucurbita maxima at highconcentrations, and it did not inhibit the promotion of growthby exogenously applied GA₉ of cucumber (Cucumis sativus) seedlings.These results suggest that the 3ß-hydroxylases fromP. vulgaris and C. maxima have different structural requirementswith respect to their substrates. 16-Deoxo-DGC also inhibitedcatalysis of the same conversion by 3ß-hydroxylasefrom P. vulgaris, and it slightly inhibited the conversion catalyzedby the enzyme from C. maxima. Application of 16-deoxo-DGC causedthe promotion of the growth of seedlings of both rice and cucumber. ³ Present address: Genetic Engineering Center, Korea Instituteof Science and Technology, Daejeon 305–606, Korea ⁴ Present address: Department of Agricultural Chemistry, UtsunomiyaUniversity, Utsunomiya-shi, Tochigi, 321 Japan (Received September 25, 1990; Accepted December 17, 1990)     

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; )     

THE RATIO OF CALCAREOUS AND ORGANIC SHELL COMPONENTS OF FRESHWATER SPHAERIID CLAMS IN RELATION TO WATER HARDNESS AND TROPHIC CONDITIONS

Shells from 14 populations of sphaeriid clams including Sphaeriumstriatinum, S. simile, Pisidium walkeri, Musculim partumeiumand M. iransversum were analyzed for organic carbon (µgCmg^–1 shell), nitrogen (µg,N mg^–1 shell) andCaCO_s (%CaCO₃ of total clam dry weight). Habitat waters wereassessed for total hardness (expressed as ppm CaCo₃), ppm Ca,ppm Mg, conductivity (µmho) and suspended organic Carbon(µgCl^–1). For all populations, shell organic C andN are positively correlated and there is an inverse relationshipbetween the amounts of shell CaCO₃ and shell organic carbon.Trophic considerations give the best correlation with shelltype at the generic level of consideration since species ofMusculium are found at the opposite end of the trophic scale(eutrophic) from all other populations studied. For S. striatinum,the most extensively studied species, the amount of shell CaCO₃is inversely related to water hardness. The selection of shellsin the Sphaeriidae is discussed in relation to structural-functionalneeds and habitat conditions ¹ Present Address: Department of Biology, Syracuse University,Syracuse, New York 13210, U.S.A. ² Present Address: Department of Zoology, Miami University,Oxford, Ohio 45056, U.S.A. (Received 5 December 1978;     

A lack of correlation between the biological activity and rate of metabolism of ent-(3H)-17-kaurenoic acid by seedlings of dwarf rice cv. Tan-ginbozu

Significant leaf sheath elongation occurred within 24 hr afterapplication of 10 µg (0.67, µCi) of ent-(³H)-17-kaurenoicacid (KA) to individual seedlings of dwarf rice cv. Tan-ginbozu,but this growth was unaccompanied by production of significantlevels of radioactivity in more polar, acidic, ethyl acetate-solublemetabolites of (³H)-KA. However modest levels of radioactivityappeared in the highly water-soluble fraction by hour 24, subsequentto the most rapid phase of KA-induced growth. Growth continuedand by hour 48 was accompanied by the appearance of small amountsof radioactivity in polar, acidic products. It would appearthat KA per se, and not its metabolic products, may be responsiblefor the leaf sheath elongation noted at hour 24. On the speculation that it might be a metabolite of KA, gibberellinA₁₄ (GA₁₄) was applied simultaneously with (³H)-KA to individualrice seedlings. Several changes in the metabolism of ³H-KA inthe presence of GA₁₄ were noted, and GA₁₄ antagonized the KA-inducedsheath elongation. ¹Present address: Botany Department, Rhodes University, Grahamstown,6140, South Africa. ²Present address: Crop Science Department, University of Saskatchewan,Saskatoon, Sask. S7N OWO, Canada. (Received May 12, 1975; )     

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)