THE EFFECT OF PROFLAVINE ON DIFFERENT STRAINS OF THE BLUE-GREEN ALGA ANACYSTIS NIDULANS

The growth of the blue-green alga Anacystis nidulans was inhibitedby relatively low concentrations of proflavine. The durationof the lag phase increased linearly with increasing proflavineconcentrations. The alga neither acquired increased toleranceto the drug during the course of six subcultures in proflavine-supplementedmedia nor was there any shortening of lag-phase or increasein final population density following repeated subculture inproflavine medium. The strain obtained after six subcultures in proflavine wasfound to have become more sensitive to streptomycin than theuntreated stock strain. A comparison of sensitivity to proflavine of two streptomycin-resistantstrains and of untreated stock strain of the alga revealed thatthe streptomycin-resistant strains were less sensitive to proflavinethan the untreated strain. The resistance of a strain resistant to 200 µg streptomycin/mlwas lost after it had been cultured once in streptomycin-freebasal medium that had been supplemented with 1 µg proflavineµml.The results obtained provide some indirect evidence for theexistence of episome in A. nidulans. ¹Present temporary address: Division of Biosciences, NationalResearch Council, Ottawa-2, Canada.     

Effects of Metabolic Inhibitors on the Calcification of a Freshwater Green Alga Gloeotaenium loitlesbergarianum Hansgirg. 2. Effects of Some Inhibitors of Protein Synthesis

The effects of five inhibitors of protein synthesis, viz. streptomycin,aurin tricarboxylic acid, tetracycline, chloramphenicol, andcycloheximide, on the calcification of Gloeotaenium loitlesbergarianumHansgirg, a freshwater green alga were studied. Streptomycinhad no effect while aurin tricarboxylic acid at 50 µgml^–1 and tetracyline, chloramphenicol and cycloheximideat 20 µg ml^–1 completely inhibited calcificationin the alga. High concentrations of chloramphenicol and cycloheximidewere not completely inhibitory when added 26 h and 32 h respectivelyafter the material was incubated in the induction medium. Itis concluded that the effects by these substrates are the resultsof inhibition of protein synthesis, which is directly or indirectlylinked to calcification. calcification, Gloeotaenium loitlesbergarianum Hansgirg, green alga, chlorophyceae, protein synthesis inhibitors     

Effects of Radiations on Blue-green Algae: I. The Production and Characterization of a strain of Anacystis nidulans resistant to Ultraviolet radiation

The unicellular blue-green alga Anacystis nidulans was exposedto ultraviolet radiation during several successive subcultures.The ultraviolet-trained strain so obtained was then comparedwith the untrained control and found to be relatively more resistantto ultraviolet, penicillin, and streptomycin, and more sensitiveto isoni-azid. It was further characterized by decreased carotenoid/chlorophyllratio and by not having fully overcome the division-inhibitingeffect of ultraviolet radiation. It was able to grow betterthan the untrained strain in a medium containing high concentrationsof nitrite as the sole nitrogen source.     

Intercellular Transport and Cytoplasmic Streaming in Chara hispida

The correlation between the velocities of cytoplasmic streamingand of translocation of ¹⁴C-photosynthate and ³²P-phosphateassociated radioactivity has been investigated in whole plantsof the green freshwater alga Chara hispida L. Tracer was suppliedto the plant's rhizoid system in a split-chamber. The velocityof cytoplasmic streaming of 52±3.3 µm s^–1compares with 57±10 µm s^–1 found for ¹⁴C-transportand 32±20 µm s^–1 found for ³²P-transport.There was no indication of intercellular translocation at avelocity faster than visible streaming. Cytochalasin B inhibitedthe translocation of ³²P and cytoplasmic streaming. CytochalasinB becomes fully effective in inhibiting streaming and transportafter an incubation time of at least 5 h. Key words: Chara hispida, Cytoplasmic streaming, Intercellular transport     

DISTRIBUTION AND TURNOVER OF PHOSPHATE COMPOUNDS IN GROWING CHLORELLA CELLS

1. Using the Chlorella cells which had been uniformly labeled with³²P, the distribution of phosphorus in various fractions ofcell material was investigated. Uniformly ³²P-labeled Chlorellawas further grown in a P-free medium or in a standard "cold"medium, and the change of distribution of ³²P (as well as theuptake of exogenous P) in various cell fractions was followed.
2. Analysis of the ³²P-labeled algal cells showed that the highestin P-content was the fraction of RNA followed by those of polyphosphates,lipid, nucleotidic labile phosphate compounds, DNA and protein(in decreasing order). ATP and ADP were found to be only minorfractions of the total labile phosphates.
3. On incubating the³P-labeled alga in a P-free medium, the P.contentsin the fractionsof DNA, protein, lipid and ATP increased, thosein polyphosphatesand ADP decreased, and that in RNA remainedalmost unchanged.When the ³²P-labeled alga was further grownin the normal "cold"medium, DNA and protein increased withthe expenditure of endogenous³²P, but with practically no incorporationof external P. Inthe meantime the P in polyphosphates decreasedconsiderably,and the RNA fraction incorporated a large amountof externalP but only a little of endogenous³²P.
4. It was inferred that,under the experimental conditions of thepresent study, thephosphorus used in the syntheses of DNA andprotein was primarilytaken from polyphosphates, while thatused in the synthesesof RNA, phospholipid and polyphosphateswas, for the most part,taken from the extracellular P-source.

¹A part of this paper was read at the Vth International Congressof Biochemistry, Moscow, August 10–16, 1961. (Received June 4, 1961; )     

Ecotypic Variation in the Osmotic Responses of Enteromorpha intestinalis (L.) Link.

Young, A. J., Collins, J. C. and Russell, G. 1987. Ecotypicvariation in the osmotic responses of Enteromorpha intestinalis(L.) Link.—J. exp. Bot. 38: 1309–1324. The physiological basis for salt tolerance has been studiedin the euryhaline marine alga Enteromorpha intestinalis. Adaptationto dilute and concentrated seawaters has been investigated inthree separate populations of this alga: marine, rock pool andestuarine. Internal K⁺, Na⁺ and Cl^– levels have been determined usingtracer efflux analyses. K⁺ has been shown to be the major osmoticsolute within this alga. Cellular levels of Cl^– and, inparticular, Na⁺ are low although levels in the cell wall arehigh. Levels of these ions varied considerably between the separateplants; K⁺ levels within marine plants of E. intestinalis aretwo to four times those found in the other populations. Thetertiary sulphonium compound ß-dimethylsulphonio-propionateis maintained at relatively high levels, although it remainsfairly insensitive to change in the external salinity. Changes in the tissue water content and cell volume are large,particularly within the estuarine plants. The thin cell wallsof these plants allow large changes in volume in the diluteconditions experienced in an estuary, while low turgor preventscell rupture. Thicker cell walls and small cells of the marineand rock pool plants assist in tolerating high and low externalosmotic potential—the estuarine plants respond poorlyto concentrated seawater. Key words: Enteromorpha, osmoregulation, ecotypes     

Effects of Plant Growth Regulators on Grain-filling and Yield of Rice

Effects of three phytohormones (IAA₁, GA₃ and kinetin) on grain-fillingand the pattern of ³²P translocation from individual leavesto grains were studied at intervals of 7 days during the progressof reproductive development of rice (Oryza saliva L. cv. Jaya).The plants were sprayed with 100 µg ml^–1 aqueoussolutions of the hormones at 100 days, when the plants wereentering the reproductive stage. Kinetin produced a pronouncedeffect on grain-filling as well as on ³²P mobilization fromindividual leaf to grains and increased yield, possibly by increasingleaf longevity. GA₃ and IAA also increased the grain-fillingand ³²P mobilization significantly over control but the effectswere less marked than those of kinetin. Oryza sativa L., rice, grain yield, translocation, growth regulators, gibberellic acid, indol-3-yl acetic acid, kinetin     

THE INCORPORATION OF 32P ORTHOPHOSPHATE INTO THE PHOSPHOLIPIDS OF ELONGATING AVENA COLEOPTILES

Four phospholipids of Avena coleoptile tissue were identifiedas phosphatidyl inositol, phosphatidyl glycerol, phosphatidylethanolamine and phosphatidyl choline. IAA caused an increase in total uptake of ³²P and incorporationof ³²P in phospholipids. IAA also caused a shift in the proportionsof identified ³²P phospholipids. Incorporation of ³²P into phosphatidylcholine was greater while incorporation into phosphatidyl glyceroland phosphatidyl ethanolamine was less in IAA-treated tissuecompared with untreated control tissue. ¹Contribution No. 338 from the Department of Botany, PennsylvaniaState University and 3001 from the Pennsylvania AgriculturalExperiment Station. ²Present address: Juniata College, Huntingdon, Pennsylvania,U.S.A.     

相对定量分析异烟肼、链霉素单耐药与多耐药结核分枝杆菌临床分离株的蛋白质组差异

【目的】探讨异烟肼(isoniazid,INH)、链霉素(streptomycin,SM)单耐药结核分枝杆菌(Mycobacterium tuberculosis,MTB)与INH/SM多耐药MTB蛋白质组差异。【方法】应用i TRAQ结合Nano LC-MS/MS定量蛋白质组学技术,分析临床分离INH、SM或INH/SM耐药MTB与H37Rv标准株间均表达差异蛋白;并以INH/SM耐药MTB与H37Rv比值为对照,相对定量分析单耐药与多耐药MTB蛋白表达差异倍数;运用DAVID 6.7分析差异蛋白生物功能;STITCH 5.0分析差异蛋白与INH和SM相互作用。【结果】与H37Rv标准株比较,58个蛋白在INH、SM耐药与INH/SM耐药MTB间均有表达差异,共同差异蛋白生物功能主要为氧化还原酶活性和转移酶活性;主要参与丙酸代谢信号通路。共同差异蛋白中,与INH/SM耐药MTB比较,Rv2986c和Rv1908c在INH、SM耐药MTB均表达上调1.25倍;Rv3133c和Rv0577则均表达下调0.7倍;生物信息学预测发现以上4种蛋白可直接或间接与INH、SM进行相互作用。【结论】INH、SM单耐药和INH/SM多耐药MTB蛋白表达谱有较大差异,蛋白Rv2986c、Rv1908c、Rv3133c和Rv0577表达水平及相互作用可能与INH和SM耐药有关。     

Nitrogen fixation and heterocysts in the blue-green alga Anabaena cylindrica

The site of nitrogen fixation in the blue-green alga Anabaenacylindrica Lemra (Fogg strain) was investigated. Less than 4%of the total nitrogen fixed during a relatively short period(5-15 min) was recovered in heterocysts. When estimated on thecellular nitrogen basis, vegetative cells can fix molecularnitrogen at the same rate as do heterocysts. There was no positivecorrelation between nitrogen fixation and heterocyst formation.Results do not support the hypothesis that the heterocyst isthe main site for nitrogen fixation in blue-green algae. ¹ This work was supported by grant (No. 38814) from the Ministryof Education. (Received July 23, 1971; )     

Effects of ethanol on the interaction of photosynthetic processes in spinach chloroplasts

The interaction and coupling between photosynthetic processeswere studied in ethanol-treated chloroplasts (in the absenceof ethanol) or in the presence of ethanol. Light-induced H⁺uptake and photophosphorylation were suppressed and electrontransfer was enhanced by ethanol treatment or in the presenceof ethanol (10–25%). Dark recoveries of the H⁺ uptakeand the 515-nm absorbance change were accelerated by ethanol.The half-effective concentrations of ethanol for these processeswere higher in the ethanol-treated chloroplasts than when ethanolwas present in the reaction mixture. The maximum rate of electrontransfer in the ethanol-treated chloroplasts, which was at thesame level as that of the control with an uncoupler, was notaffected by uncouplers. The marked acceleration of recoveryof the 515-nm absorbance change by SCN- or valinomycin plusK⁺ in the untreated chloroplasts was much smaller in the ethanol-treatedchloroplasts or in the presence of ethanol. The ethanol-treatedpreparation had the same characteristics as those of the control,in chlorophyll fluorescence, light-intensity dependence of electrontransfer (compared with the control with an uncoupler), andsensitivity to sucrose osmolarity except for a slight increaseof the packed volume. Under the present conditions, the ethanoltreatment mainly induced an increase of permeability of thylakoidmembranes to ions. In chloroplasts treated with ethanol at various concentrations,the relationships of the uncoupler-stimulated part of electrontransfer with the dark half-recovery time of H⁺ uptake and withphotophosphorylation were linear. Logarithms of the photophosphorylationand the extent of H⁺ uptake had a linear relationship with aslope of about 3. This slope may indicate the stoichiometryof H⁺/ATP. (Received June 17, 1978; )     

Action spectrum of negative phototropism in Boergesenia forbesii

The rhizoid of Boergesenia forbesii, a gigantic unicellulargreen alga, exhibited negative phototropism. The bending processat 32?C followed Weber-Fechner's law and Bunsen- Roscoe's law.The minimum light energy inducing the phototropic bending was30 J.m^–2 at 467 nm and 32?C. The action spectrum of thisnegative phototropism had two distinct peaks at 380 and 443nm, with shoulders at 430 and 470 nm and a trough around 410run. Light of wavelengths longer than 502 nm was ineffective.The structure of the spectrum agrees well with that reportedfor the positive phototropism of Avena coleoptiles and otherplant parts. (Received February 24, 1979; )     

Effects of chronic, low levels of UV radiation on carbon allocation in Cryptomonas erosa and competition between C.erosa and bacteria in continuous cultures

We conducted a long term (4 week) continuous culture studyto measure the chronic effects of UV radiation on the alga,Cryptomonas erosa, using three different fluence rates of UVradiation. We measured carbon allocation into carbohydrate,protein and lipid pools, as well as chlorophyll a concentrationsand algal and bacterial density. After 21 days, algal densityin the control and lowest UV treatment (treatment 1 = 3.4 Wm^–2 UVR unweighted) was significantly lower than in thetwo highest UV treatments (treatment 2 = 14.9 W m^–2 andtreatment 3 = 16.2 W m^–2 UVR unweighted), and did notrecover in the following week of no UV exposure. Chlorophylla and carbohydrate content (ng algal cell^–1) for the controland treatment 1 were clearly lower than treatments 2 and 3 byday 15, and did not recover by day 28. Percentage total lipidfor the control and treatment 1 also decreased compared withtreatments 2 and 3 by the end of the exposure period. However,by day 21, protein content for the control and treatment 1 wassignificantly higher than treatments 2 and 3, and demonstrateda further increase by day 28. The results were largely attributedto competition effects between C.erosa and bacteria in thesenon-axenic cultures. Bacterial density was significantly (x4)higher in the control and lowest UV treatment compared withthe two highest UV treatments. Our findings suggest a competitiveadvantage of phytoplankton over bacteria under these conditions.If UV radiation, in general, affects bacteria to a greater extentthan algae, there are likely to be changes in (i) bacterialutilization of dissolved organic matter produced by phytoplankton,(ii) competition between phytoplankton and bacteria for nutrientminerals and (iii) predation rates on bacteria by micro-flagellates.     

Solute Regulation in the Euryhaline Marine Alga Enteromorpha prolifera (O. F. Mull) J. Ag.

Young, A. J., Collins, J. C. and Russell, G. 1987. Solute regulationin the euryhaline marine alga Enteromorpha prolifera (O. F.Mll) J. Ag.—J. exp. Bot. 38: 1298–1308. The physiological basis for salt tolerance has been studiedin the euryhaline alga Enteromorpha prolifera. Levels of inorganicions and organic (compatible) solutes have been measured. K⁺makes the major contribution towards the internal osmotic potentialof the cell, while Cl^– and, in particular, Na⁺ contentsare low. Levels of the organic solute ß-dimethylsulphonio-propionate(DMSP) are high but are fairly insensitive to changes in theexternal salinity. Levels of amino-acids, calcium, phosphateand sulphate contribute relatively little towards the internalosmotic potential of the alga. As salinity is altered there are marked changes in the tissuewater content and volume. These changes directly affect theconcentration of the osmotic solutes within the cell. In diluteseawaters there is an increase in turgor as there is littlechange in the internal solute content of the cell compared tovalues in normal sea water. Inorganic ions, in particular K⁺,and organic solutes are accumulated in concentrated seawaters,although concentrations greater than 2·00 x seawaterresult in a reduction in the internal osmotic potential of thecell, mainly through loss of K⁺. Key words: Enteromorpha, salinity, osmoregulation     

A probable lack of function of c-type cytochrome in the photosynthetic system of the blue-green alga Anabaena variabilis

Quantitative study of the cytochrome c acting in the photosyntheticsystem of the blue-green alga Anabaena variabilis (M-2) wasdone with membrane fragments and intact cells. Membrane fragments highly active in the NADP⁺-Hill reaction(above 200 µmoles/mg chl.a;-hr) retained photoresponsivecytochrome c equal only one-tenth that of P700, while the plastocyanincontent was almost equal to that of P700. The cytochrome contentin intact cells was a little larger than that in membrane fragmentson the chlorophyll a basis. However, the values relative toP700 (1/9) and plastocyanin (1/10) were identical with thosein membrane fragments. The content was also far smaller thanthat of reaction center II's (1/6). If the cytochrome mediatesall electrons from reaction center II, the cytochrome oxidation-reductionshould have a rate constant of 2.4?102 sec^–1 which isone order above of the rate constant of the cytochrome reduction(2.3 to 3.5?10¹sec^–1). These quantitative relationshipsindicate that in Anabaena variabilis (M-2), c-type cytochrome,either cytochrome f or algal cytochrome c, cannot function inthe main electron flow between two reaction centers. (Received September 8, 1978; )     

Abolition of Heavy Metal Toxicity on Kirchneriella lunaris (Chlorophyta) by Calcium

The green alga Kirchneriella lunaris was incubated with variousheavy metals (Cd²⁺, Co²⁺, Mn²⁺, Ni²⁺) in presence/absence ofcalcium (Ca²⁺). The uptake of heavy metal was affected by Ca²⁺.Growth rate was inhibited by all heavy metals applied. In allCa²⁺-containing cultures Kirchneriella exhibited higher ratesof growth than those containing heavy metal alone. Photosynthesis/respirationratio of K. lunaris cells seems to be the determinant in thiswork. Ca²⁺ variably abolished the effects of the heavy metalsstudied. Maximal positive effect of Ca²⁺ was found with Cd²⁺while with Ni²⁺ it was negligible.Copyright 1995, 1999 AcademicPress Cadmium, cobalt, manganese, nickel, calcium, heavy metals, growth, photosynthesis, Kirchneriella lunaris     

Phosphorylation of myo-inositol in ripening grains of rice and wheat. Incorporationof phosphate-32P and myo-inositol-3H into myo-inositol phosphates

To elucidate the mechanism of the phosphorylation of myo-inositolin the process of phytate formation, feeding experiments oforthophosphate-³²P and myo-inositol-³H in the ripening grainsof rice and wheat were performed. It was found that ³²P and³H were incorporated into myo-inositol mono- and hexa-phosphates.The same results were obtained when a mixture of "cold" myo-inositolpolyphosphates was administered to the grains before feedingphosphate-³²P. Based on these results it is concluded that phosphorylationof free myo-myo-inositol in the formation of phytate does nottake place in a stepwise fashion but may proceed through anunknown myo-inositol derivative. (Received August 2, 1967; )     

The Effect of Isonicotinyl Hydrazide on the Photosynthetic Incorporation of Radioactive Carbon Dioxide into Ethanol-Soluble Compounds of Chlorella

The effect of 10^-2M. isonicotinyl hydrazide (isoniazid) on theincorporation of radioactive carbon dioxide by Chlorella duringphotosynthesis has been studied under steady-state conditionsat two carbon dioxide concentrations. Isoniazid treatment resultsin increased radioactivity in sucrose, glycollic acid, and glycineand decreased radioactivity in sugar monophosphates, serine,and alanine. An unidentified compound which is strongly radioactiveafter short-term exposures to ¹⁴CO₂ is present in isoniazid-treatedcells. It is suggested that isoniazid pre-dominantly inhibitsthe conversion of glycine to serine.     

Effects of Glycollate on the Growth of a Planktonic Chlorella

The duration of the lag phase in cultures of a planktonic strainof Chlorella pyrenoidosa growing from small inocula under conditionsof light limitation was shortened by the addition of 1 mg 1^–1of glycollate to the medium. Of eight related compounds tested,none, with the possible exception of lactate, had a similareffect. Addition of 1 mg 1^–1 of glycollate also considerablyincreased the relative growth-rate of the alga at low (500 lux)but not at higher light intensities. This effect was not, however,specific to glycollate. Concentrations of glycollate (20 mg1^–1) higher than those normally produced in cultures byexcretion had an inhibitory effect on growth.     

Relative impacts of copepods, cladocerans and nutrients on the microbial food web of a mesotrophic lake

Calanoid copepods, rather than cladocerans, frequently dominatethe zooplankton of lakes in New Zealand. The potential consequencesof this domination for the microbial community of mesotrophicLake Mahinerangi, New Zealand, were determined by field experimentsin which Boeckella and Daphnia were added to in situ enclosuresin the presence and absence of added nutrients. Boeckella hamataat ambient densities (2 and 81^–1) rapidly and severelysuppressed ciliate population growth over 4 days, even whenmicrobial growth was enhanced by added nutrients, but effectsof copepods on other components of the microbial community (bacteria,photosynthetic picoplankton, heterotrophic nano-flagellates,algae) were slight. In contrast, Daphnia carinata at the samedensities (but 3-fold higher biomasses per litre) had a relativelyweak effect on ciliates, suppressing ciliate abundance onlyafter 4 days at 8 Daphnia 1^–1 (330 µg 1^–1);this daphniid density also depressed abundances of large bacterialrods, some photosynthetic picoplankton and the dominant alga,Cyclotella. These results highlight the relative importanceof specific trophic linkages in a microbial food web; they alsosuggest that the dominance of Boeckella in many southern hemispherelakes may account for relatively low ciliate abundances in theselakes.