Kinetochore and microtubules in two members of Chlorophyceae,Cladophora fracta and Spirogyra majuscula

Evidence is presented for the existence of a localised kinetochore with stratified fine structure in Cladophora and in Spirogyra. In the latter, there is the possibility of two kinetochores on the longer chromosomes. There is no evidence for a diffuse kinetochore. The nucleolus persists during mitosis in Cladophora on the nucleolar organising chromosomes, the granular material being lost from it very largely during metaphase and anaphase but the fibrillar material remaining. The persistent nucleolar material at metaphase and anaphase in Spirogyra is not attached to the nucleolar organising chromosomes but accumulates around all the chromosomes and chromatids, the microtubules of the spindle at anaphase passing through and possibly attaching to this nucleolar material and possibly assisting in the movement of the chromatids which are embedded within it.     

CHANGES IN RESTING POTENTIAL AND ION ABSORPTION INDUCED BY LIGHT IN A SINGLE PLANT CELL

1. Effect of light on ion absorption and resting potential of theinternodal cell of Nitella flexilis was investigated under variousconditions.
2. On illumination, the resting potential increasedby about 30mVin 10^–4 M KCl and by about 60 mV in 10^–4M NaClsolution. A similar photoelectric response was also observedin 10^–3 M KCl, 10^–2 M CaCl₂ and 5 x 10^–2 MCaCl₂ solutions, but not at all in 10^–2 M KCl solution.
3. Absorption of ions by the cell took place in parallel withthelight-induced change in resting potential.
4. Red and bluelights were very effective in increasing the restingpotential,while green light was almost ineffective. These differenteffectsof color lights were in good agreement with their effectsinincreasing the osmotic value of the cell.
5. The photoelectricresponse was not affected by phenylurethane,which, on the otherhand, strongly inhibited the light-inducedion absorption.
6. Theuptake of ions by the cell from the external medium intothevacuole is assumed to proceed in two different steps: thefirstis the process involving the ion movements across theoutermostplasmalemma, and the second is that involved in thetransportof ions through the cytoplasmic layer and tonoplast.The formerprocess is considered to be influenced by the increasein restingpotential probably caused by the light absorbed bychlorophyll.The process was, however, suggested to be independentof photosynthesis.On the other hand, the latter process issupposed to be relatedto photosynthesis. A discussion was madealong this line.

(Received July 26, 1962; )     

Studies in the Nitrogen Metabolism of Apple Fruits: THE CLIMACTERIC RISE IN RESPIRATION IN RELATION TO CHANGES IN THE EQUILIBRIUM BETWEEN PROTEIN SYNTHESIS AND BREAKDOWN

1. A close parallelism in the drift of the rate of respirationand the protein-N/ non-protein-N ratio is shown to occur bothin apple fruits attached to the tree and when detached fromthe tree at various stages of development and stored for severalmonths at 12 C.
2. In detached fruits the fall in respirationwhich occurs immediately(during the first 48 hours) after pickingis only accompaniedby a concomitant fall in net protein invery young fruits inwhich active cell division is taking place.Subsequently, infruit of all ages when a climacteric rise inrespiration occursit is accompanied by a net increase in protein.
3. It is argued that the climacteric rise in respiration is aresultof increase in the level of protein which will be expectedtoreduce the ATP/ADP ratio.
4. Over the climacteric period,although rate of respiration andnet protein content both rise,R rises more rapidly than proteinand, subsequently, falls ata faster rate than P. It is suggestedthat this may be due tothe ‘new’ protein containinga higher proportionof enzyme(s) directly involved in respirationand leading, forexample, to a reduction in the ATP/ADP ratio.

     

WATER PERMEABILITY OF THE CELL WALL IN NITELLA

1. A method has been developed to measure the hydraulic conductivityof the wall of the internodal cell of Nitella flexilis.
2. Therate of water penetration through the cell wall varies linearlywith the hydrostatic pressure difference between the two sidesof the wall, showing that water permeability of the cell wallremains independent of the pressure difference applied.
3. Waterpermeability of the cell wall is inversely proportionalto itsthickness It is 30µµmin^–3{dot}atm^–3when the thickness of the wall is 10 µ.
4. Water permeabilityof the cell wall is the same for inward andoutward water flow.The polar water permeability of the entiremembrane system (walland protoplasmic part) of the living celldemonstrated by KAMIYAand TAZAWA (1) is, therefore, due tothe living protoplasmicpart.
5. The ratio of the inward to outward permeability constantsofthe protoplasmic layer alone is higher than that of the entiremembrane system composed of protoplasmic layer and cell wall.

¹ Dedicated to Prof. H. TAMIYA on the occasion of his 60th birthday.The present work was supported in part by a Grant-in-Aid forFundamental Scientific Research from the Ministry of Education. ² Present address: Sh?in Women's College, Kobe. (Received July 21, 1962; )     

Biological activity of phyllosinol, a phytotoxic compound isolated from a culture filtrate of Phyllosticta sp.

1. Phyllosinol is a phytotoxic metabolite of Phyllosticta sp. Thissubstance at 100 µg/ml produced dark grey necrotic lesionson the leaf of red clover. Sensitivities of various plant speciesto phyllosinol differed both quantitatively and qualitatively.
2. Phyllosinol reduced root growth in rice seedlings by 60% at10^–4 M, whereas stimulation of root elongation occurredat a concentration range from 10^–9 to 10^–5 M.
3. Phyllosinolat 2.5x10^–4M promoted adventitious root formationin epicotylsof Azukia cuttings by about 100%. Promotion waspartly reducedby simultaneous application of cysteine.
4. IAA-induced elongationof isolated Avena coleoptile sectionswas inhibited by phyllosinolat a concentration range from 10^–5to 10^–3M.
5. Sulfhydrylcompounds, i.e. cysteine and glutathione relievedinhibitioncaused by phyllosinol in IAA-induced elongation ofAvena coleoptilesections.
6. GA₃-induced elongation of wheat leaf sections wasslightly inhibitedby phyllosinol at 10^–4M.
7. Phyllosinolalso has antibiotic activity. Among the organismstested, Phycomycetesand Gram-negative bacteria appeared mostsusceptible to phyllosinol.

(Received April 21, 1970; )     

PHOTOCHEMICAL INTERCONVERSION BETWEEN PRECURSORS OF PHYCOBILIN CHROMOPROTEIDS IN TOLYPOTHRIX TENUIS

1. The photochemical conversion between the precursors of phycocyaninand phycoerythrin in Tolypothrix tenuis was investigated.
2. Itwas found that the conversion of phycocyanin-precursor intophycoerythrin-precursor was induced by green light, and thereverse reaction by red light. These reactions proceeded exponentially, indicating that the photochemical process was acceleratedautocatalytically by the reaction-product.
3. The rates of thesephotochemical reactions were found to beunaltered by varyingthe incubation temperature (0? to 35?)and the composition ofthe gas atmosphere (presence or absenceof CO₂ and of O₂ orby an inhibitor of photosynthesis, p-chlorophenyldimethylurea.
4. The action spectra of the photochemical interconversions betweenprecursors of phycobilin chromoproteids were found to be distinctlydifferent from the absorption spectra of chlorophyll and carotenoids.The most effective wavelength for inducing the conversion ofphycocyanin- into phycoerythrin-precursor (541 mµ) isnear the absorption maximum of phycoerythrin (565 mµ),and that of the reverse reaction (641 mµ) is near theabsorption maximum of phycocyanin (620 mµ). Additionaldata, indicating that the phycobilin chromoproteids themselvesdo not participate in these processes as light absorber, werealso presented.
5. On the basis of these results, a possiblemechanism of the photochemicalinterconversion between the precursorsof phycobilin chromoproteidsis proposed.

(Received March 13, 1962; )     

The Effect of Prolonged Chilling on Water Movement and Radial Growth in Trees

1. The woody shoots of young saplings of Fraxinus.excelsior andAcer Pseudo-platanus in pots were subjected to continuous coolingto about 2° C. during the growth season, with the resultthat radial growth was almost completely inhibited throughoutthe woody stem.
2. The chilling did not adversely affect extensiongrowth exceptthat it was later in commencement and proceededmore slowly.
3. If the temperature around the stem is loweredfrom 2° C.to 0° C., water conduction is cut down tosuch an extentas to cause wilting of the leafy shoots; turgidityis recoveredwhen the temperature is again raised to 2°C.
4. This wilting effect is discussed particularly in relationtothe part played by living cells in the upward movement ofwaterin the wood.

     

Studies on Plant Growth Hormones: I. BIOLOGICAL ACTIVITIES OF 3-INDOLYLACETALDEHYDE AND 3-INDOLYLACETONITRILE

1. Two neutral plant hormones, one isolated recently from plants(3-indolylacetonitrile) and the other (3-indolylacetaldehyde)reported to be present in plants, are avaible as pure syntheticcompounds for investigation of their biological activities.This paper is mainly concerned with their effects on cellelongationin the Avena coleoptile
2. 3-Indolylacetaldehyde is considerablyless active than 3-indolylaceticacid in the Avena straight-growthtest; for example, a 1.0 mg./l.solution of the aldehyde showsan activity equivalent to thatof a 0.1 mg./l. solution of theacid
3. An acidic substance is produced in solutions of the aldehydeduring the period of assay. In some experiments it accountsfor all of the activity shown by the aldehyde solutions, onthe assumption that it is 3-indoylacetic acid, and in otherexperiments it shows a greater activity than that of the aldehydesolutions from which it was obtained. Therefore, it is concludedthat 3-indolylacetaldehyde, itself is either inactive or inhibitory.Acid production in aldehyde solutions in vitro is much lower,a fact which suggests that there is enzymatic oxidation of aldehydeto acid in the presence of coleoptiles.
4. The activities of3-indolylacetaldehyde in the pea test andin root-inhibitionand of 3-indolylacetone in the straight-growthtest are brieflyreported.
5. 3-Indolylacetonitrile is considerably more activethan 3-indolylaceaticacid in the Avena straight-growth test;for erample, a 0.1 mg./l.solution of the nitrile shows an activityequivalent to a 1.0mg./l. solution of the acid. The inhibitoryeffect at concentrationsabove 1.0–10.0 mg./l. is lesswith the nitrile than withthe acid.
6. There is negligible productionof acid in solutions of the nitrileboth in vitro and in thepresence of Avena coleoptiles at temperaturesranging from –18?to 25? C. for varying lengths of time.The possibility of enzymaticconvesion of nitrile to acid insidethe cells of the coleoptileis discussed
7. The activities of 3-indolylacetamide and of 2:4-dichlorophenoxyaceticacid and the corresponding nitrile are considered in this connexion
8. The nitrile is destroyed by treatment with alkali but notbyacid. In the light of these results, it is desirable to re-examineprevious work on identification of auxins in plants by theiracid and alkali sensitivity. Evidence for the existence of thenitrile in a number of other plants is presented.

     

The Time Factor in Studies of Growth Inhibition in Excised Organ Sections

1. Apprehension over the adequncy of current techniques stimulateda detailed study of the time factor in the arsenate inhibitionof growth and respiration in excised stem and root sectionsof Pisum sativum.
2. Growth inhibition by arsenate sets in veryslowly, its rateof onset being related to the molar concentration(C) of arsenateate by the relation where T₅₀ is the time taken in hours to reduce the growthrateto 50 per cent of the control and K is a constant. An explanationof the physiological basis of this relationship is attempted.
3. Estimates were made of the final steady growth rate (relativeto control) in various arsenate concentrations. The inhibitionscalculated from this rate are held to approximate to the truearsenate effect and are shown to be very different from thosecalculated from ‘total growth’ measures.
4. Respirationof growing stem sections is not inhibited by thelow arsenateconcentrations that inhibit growth. Some inhibitionis indicatedat high concentrations (3 ? 10^–4M. and over)but onlyafter 15-20 hours of exposure.
5. Two per cent sucrose has noeffect on the arsenate inhibiitionof stem growth. Sucrose,however, markedly stimulates respirationin stem sections, butthis stimulation is prevented by arsenate.
6. The misinterpretationswhich may arise as a result of ignoringthe time factor in inhibitionstudies in excised organ sectionsare discussed and the desirabilityof constructing completegrowth curves in all such studies isstressed.

     

LACTATE OXIDATION SYSTEM IN ACETOBACTER SUBOXYDANS, WITH SPECIAL REFERENCE TO CARBON MONOXIDE-BINDING PIGMENT

1. Lactate oxidation system was investigated in Acetobacter suboxydans,which was found to have cytochromes a and b, but no cytochromec. Haemoprotein 558 was also found to exist.
2. Carbon monoxideinhibited the lactate oxidation in the darkbut not in the light.WARBURG'S partition constant was estimatedto be 7.
3. Additionof haemoprotein 558 noticeably enhanced the oxygenuptake bythe LDH preparation, which was obtained from bacterialcellsand partially purified.
4. Haemoprotein 558 has protohaem asits prosthetic group. Notonly its absorption spectrum is reminiscentof that of peroxidase,but it also shows peroxidase-like reactivitywith some ligandswith a few exceptions.
5. Ferrohaemoprotein558 reacts with oxygen, forming, at first,a complex, whichhas its SORET absorption peak at 423 mµ.The absorptionmaximum then shifts to 417 mµ, indicatinga transformationto another compound. One of these two productsis likely tobe the oxygenated ferro-haemoprotein 558.
6. The mutual transformationbetween cytochrome B and haemoprotein558 is discussed.

(Received October 8, 1965; )     

Organic Acid Metabolism of Sedum praealtum

1. The organic acids present are citric, isocitric, and l-malic,with a small residue of unidentified acids.
2. The diurnal variationin acidity is due chiefly to changes,in malic acid, with aparallel fluctuation shown by citric acid.Under these conditionsisocitric acid shows little change.
3. The importance of carbondioxide during acidification is confirmed,and it is shown thatat room temperatures or higher the CO₂produced in respirationis sufficient to produce maximum acidification.At lower temperaturesthe supply of CO₂ limits acid production.
4. In the absence ofoxygen no acidification occurs, but even smallquantities (approx.1 per cent.) are sufficient to cause someacid production.
5. Completebalance-sheets are presented for acids, carbohydrates,CO₂ andoxygen for leaves maintained in the dark at high andlow temperatures.As acids are produced there is a correspondingloss of carbohydrate(chiefly starch). A scheme of reactionsis suggested to explainthe experimental results.

     

STUDIES ON THE MECHANISM OF GROWTH INHIBITING EFFECT OF LIGHT

1. A substance which inhibits indoleacetic acid (IAA)-and naphthaleneaceticacid (NAA)-induced elongation of Avena coleoptile section andIAA-induced Avena coleoptile curvature was found in an ethersoluble neutral fraction of water extract of sunflower leavesand in agar blocks containing the diffusate from young sunflowerleaves.
2. This substance also inhibits the growth of isolatedsunflowerepicotyl.
3. The R_f value (0.9) of the substance ona paper chromatogramdeveloped with ammoniacal iso-propanolindicates that it isidentical with the inhibitor reported byAUDUS et al. (1956),but not with inhibitor-ß.
4. Theinhibitor can be transported from leaf to stem, and thetransportseems to be accelerated by illuminating the leaf.
5. The auxindiffused from sunflower leaf into agar block may beidenticalwith IAA.
6. A substance, which has the same properties as theinhibitorfrom sunflower leaf, was obtained in crystalline formfrom theleaf of Jerusalem artichoke.
7. The mechanism of growthinhibition caused by this crystallinesubstance seems to involveinactivation of a sulfhydryl group.
8. The reason why the stemgrowth of sunflower seedlings is reducedby strong light isdiscussed: the amount of the inhibitor transportedfrom leafto stem is increased under strong light, and in thestem, growthinhibition is caused by a direct effect of thisinhibitor ongrowth and by its inhibiting effect on the transportof IAAfrom leaf to stem.

¹ Present address: Botanical Garden, Faculty of Science, Universityof Tokyo, Tokyo (Received February 15, 1961; )     

PROMOTION OF ADVENTITIOUS ROOT FORMATION BY HELIANGINE AND ITS REMOVAL BY CYSTEINE

1. Heliangine at 10^–4M promoted the adventitious root formationin hypocotyls of cuttings taken from light-grown (1,900 lux)seedlings of Phaseolus mungo. The promotion was almost completelyreduced by simultaneously supplied 310^–4M cysteine or1.510^–4M cystine, but not suppressed by 310^–4Mof reduced glutathione, alanine or serine.
2. A 4 hr pretreatmentwith 310^–4M cysteine made Phaseoluscuttings less sensitiveto heliangine, but cysteine suppliedafter the treatment withheliangine brought about no effecton the action of heliangine.
3. Cysteine also removed the inhibiting effect of heliangineonthe indoleacetic acid-induced elongation of etiolated Avenacoleoptile sections.
4. In an aqueous solution heliangine formedan addition productwith cysteine, indicating that cysteinecan inactivate helianginewithout any biological processes.
5. On Phaseolus adventitious rooting, no effect was observedofp-chloromercuribenzoic acid, N-ethylmaleimide, 1,4-naphthoquinone,coumarin or penicillin. Reactivity toward sulfhydryl groupsalone does not qualify a substance to be a promotor of rootformation.
6. Maleic hydrazide at 10^–4M promoted root formation,butits effect was not removed by cysteine.

¹ Contribution No. 13 from the Botanical Gardens, Faculty ofScience, University of Tokyo, Koishikawa, Tokyo.     

The Assimilation of Nitrogen from Ammonium Salts and Nitrate by Fungi

1. The assimilation of inorganic nitrogen by Scopulariopsis brevicaulisand some physiologically similar species has been studied. Theirfailure to assimilate completely from ammonium sulphate hasbeen shown to be due to the fall in pH of the medium inducedby the initial uptake of ammonia.
2. Complete assimilation ofammonia takes place in the presenceof the neutral salts ofeach of thirteen organic acids investigated.The organic acidsact primarily through their buffering effectwhich preventsor slows down the fall in pH. They are not specificallyrequiredfor ammonia assimilation by these fungi and can beeffectivelyreplaced by certain inorganic buffers.
3. The influence of severalexternal factors on the rate of assimilationof ammonia, nitrate,and nitrite has been studied in S. brevicaulis.In correspondingconditions the mycelium assimilates ammoniamore rapidly thannitrate over a wide range of conditions.
4. Ammonia, even invery low concentration, completely suppressesnitrate assimilationwhen both sources of nitrogen are presenttogether. Nitrite,however, is assimilated simultaneously withammonia. It is thereforeconcluded that ammonia blocks the reductionof nitrate to nitriteby the fungus.
5. The suppression of nitrate assimilation inthe presence of ammoniais common to many mould fungi besidesS. brevicaulis, and isbelieved to have adaptive significancein natural habitats.
6. The nitrate-reducing and assimilatingsystem is formed, evenwhen S. brevicaulis is grown in completeabsence of nitrate(ammonia medium with organic acid). It comesinto action rapidlywhen the inhibiting effect of ammonia isremoved. Similarly,nitrate-grown mycelium is capable of assimilatingammonia atmaximal rate without any adaptive lag.

     

COMPONENTS OF THE ELECTRON-TRANSFERRING SYSTEM IN ACETOBACTER SUBOXYDANS AND RECONSTRUCTION OF THE LACTATE OXIDATION SYSTEM

1. Cytochromes a₁⁵⁹⁰, b⁵⁶⁰, c₁⁵⁵⁴ and c₁⁵⁵² were isolated andpurifiedfrom a strain of Acetobacter suboxydans. The proceduresusedwere described in detail.
2. The main cytochrome band at550-560 mµ in intact cellssplitted at liquid air temperatureinto two bands, 551 mµ(strong) and 559 mµ (weak).
3. Optical and physiological properties of the four cytochromeswere investigated. Lactic dehydrogenase activity was found tobe associated with cytochrome c₁⁵⁵⁴. The two c₁-type cytochromes,especially cytochrome c₁⁵⁵⁴, persisted in their reduced formafter the purification through many steps.
4. By some combinationsof isolated components reconstruction ofthe oxygen uptake systemcould be realized.
5. The oxygen-consuming activity of purifiedoxidase preparationswas accelerated by a-tocopherol but notby Emasoll 4130 andTween 80.
6. Some discussions were made onthe nature of terminal oxidase,the role of cytochrome c₁⁵⁵²in the electron-transport system,and persistence of reducedstate of c₁-type cytochromes.
7. A possible scheme of the electron-transferringsystem of Acetobactersuboxydans was presented.

(Received May 16, 1960; )     

INTERACTION BETWEEN HELIANGINE AND PYRIMIDINES IN ADVENTITIOUS ROOT FORMATION OF PHASEOLUS CUTTINGS

1. Heliangine at 110^–4 M promoted the adventitious rootformation in hypocotyls of cuttings taken from light-grown (1,900lux) Phaseolus mungo seedlings. The promotion was almost completelyreversed by 310^–4 M uracil, uridine, cytidine, oroticacid or 610^–4 M carbamoyl DL-aspartic acid, and partlyby 310^–4 M thymine or thymidine. Neither 310^–4M cytosine, adenine, adenosine, guanine, guanosine nor a combinationof 310^–4 M carbamoyl phosphate and 310^–4 M L-asparticacid reduced the promotion by heliangine.
2. Uracil did not reducethe inhibiting effect of heliangine onthe indoleacetic acidinduced elongation of etiolated Avenacoleoptile sections.
3. Helianginein an aqueous uracil solution was recovered unchangedafter24-hr incubation at room temperature.
4. The root formation ofPhaseolus cuttings was promoted also by2-thiouracil and 5-fluorouracil.The effect was reversed byorotic acid or carbamoyl asparticacid, but not by carbamoylphosphate plus aspartic acid.
5. Ribonucleaseat 100 µg/ml increased the number of rootsprotruded fromhypocotyls of cuttings by about 260%.
6. A possible interpretationfor the promotion of root formationby heliangine is offered.

¹ Contribution No. 15 from the Botanical Gardens, Faculty ofScience, University of Tokyo, Tokyo, Japan. ² Dedicated to Prof. Dr. H. SODING in commemoration of the 70thbirthday.     

The Genetic Basis of Preference for Sweet Substances Among Inbred Strains of Mice: Preference Ratio Phenotypes and the Alleles of the Sac and dpa Loci

Five inbred strains (129/J, BALB/cByJ, C3HeB/FeJ, C57BI/6J andDBA/2J) were examined with two-bottle (48 h) preference ratiotesting across concentrations of sodium saccharin (3 x 10^–4M, 10^–3 M, 3 x 10^–3 M and 10^–2 M), d-phenylalanine(10^–3 M, 10^–2 M and 10^–1 M), and l-glutamine(10^–2 M, 3 x 10^–2 M, 10^–1 M and 3 x 10^–1M). Three consistent groupings of strains were observed acrosssubstances and concentrations:

1. C57BI/6J (preference at low andhigh concentrations);
2. BALB/cByJ and C3HeB/FeJ (preferenceat high concentrations);
3. 129/J and DBA/2J (preference at highconcentration for sodiumsaccharin and indifference to d-phenylalanineand l-glutamine).

If a single locus (presumably dpa or Sac) determines these phenotypes,there are likely to be three alleles. If two independent loci(presumably dpa and Sac) determine these phenotypes, an allelicassignment of Sac^b/dpa^+s for the C57BI/6J strain, Sac^b/dpa^–sfor the BALB/cByJ and C3HeB/FeJ strains, and either Sac^d/dpa^+sor Sac^d/dpa^–s for the 129/J and DBA/2J strains is suggested.Chem. Senses 20: 291–298, 1995.     

Society for Molecular Biology and Evolution (SMBE) Council and Business Meetings, 2004 State College, Pennsylvania, USA

Council Meeting

1. Call to order.—President John Avise called the meetingto order at 9:00 AM, 17 June 2004. In attendance were PresidentJohn Avise, Treasurer Marta L. Wayne, Editorial Advisory Boardmember Stanley A. Sawyer, Editor William Martin, Past- PresidentNaoyuki Takahata, Secretary Sudhir Kumar, and Councillors G.Brian Golding, Laura A. Katz, and Jody Hey. President-ElectJeffrey R. Powell arrived later due to flight delays. The meetingbegan with Introductions.
2. Approval of minutes.—Councilapproved the minutes of the2003 Council and Business meetings,published in the December2003 issue of the journal MolecularBiology and Evolution (MBE).
3. Editor's report.—Most ofthe meeting addressed a discussionconcerning the Journal'sfuture and dealings with the OxfordUniversity Press (OUP) (seereport).
4. Treasurer's report.—Treasurer Marta L. Waynesummarizedthe financial state of the Society (see report).The fiscalyear has now changed to January–December (coincidentwith     

CHANGES IN EMISSION SPECTRA OF PHOTOSYNTHETIC PIGMENTS IN VIVO

1. The effects of 3-(4'-chlorophenyl)-1, 1-dimethylurea (CMU)onthe fluorescence of photosynthetic pigments in vivo wereinvestigatedin blue-green, red and brown algae and in isolatedspinach chloroplasts.CMU caused an increase in steady statelevel of fluorescenceof chlorophyll a, but did not influencethe fluorescence ofphycobilins. The spectrum of the fluorescenceincrement hada peak at 685 m/µ and a shoulder at 730–740mµ.These two bands probably arise from chlorophyll a(C_f684) belongingto pigment system II.
2. On excitation of chlorophylla in a red alga, Porphyra yezoensis,a fluorescence band witha peak at 720 mµ was observedbesides a shoulder at 685mµ. The 720 m band is inferredto arise from chlorophylla (probably, C_f-1) in pigment systemI.
3. On addition of CMUto the algal cells, the induction of fluorescencewas modifiedto take a simple time course. The induction wasobserved onlywith respect to the fluorescence of chlorophylla, but not inthe fluorescence of phycobilins. The spectrumof the "transient"fluorescence showed two emission bands ofchlorophyll a at 685mµ and 740 mµ, and was quitesimilar in form tothe spectrum of the CMU-caused increase insteady state fluorescence.
4. These facts were interpreted in terms of the correlation offluorescence of chlorophyll a and the photochemical reactionsof photosynthesis

(Received July 20, 1967; )     

STUDIES ON LACTATE CYTOCHROME C REDUCTASES OF YEAST WITH SPECIAL REFERENCE TO ELECTROPHORESIS ON POLYACRYLAMIDE GEL

1. Two lactate dehydrogenases, L(+)- and D(–)- lactate cytochromec reductase, were extracted from the baker's yeast after disintegrationof the cells by a FRENCH press. They are separated by electrophoresison polyacrylamide gel and their activities were compared bycolor density of formazan, the reduction product of nitrobluetetrazolium.
2. The ratio of L-lactate cytochrome c reductaseactivity to D-lactatecytochrome c reductase activity variedto a great extent, dependingon culture conditions. L-Lactatecytochrome c reductase waspredominant in resting cells; thereverse was the case withcells in early exponential stage ofthe growth.
3. When the cells in exponential stage of growthwere aerated withoutnitrogen source, there occurred an intensiveincrease of L-lactatecytochrome c reductase, accompanied bythe decrease of D-lactatecytochrome c reductase.
4. Effectsof inhibitors on the activity ratio of these two enzymeswereinvestigated. o-Phenanthroline, dinitrophenol, sodium azide,chloramphenicol, British antilewisite and antimycin A favored,in this order, the formation of L-lactate cytochrome c reductase.

(Received August 18, 1966; )