Cyanidium caldarium as a bridge alga between Cyanophyceae and Rhodophyceae: Evidence from immunodiffusion studies

The primer-independent phosphorylase isozyme, a₂, of Cyanidiumcaldarium was used for immunization of rabbits. The immune serumwas tested against pure a₂ isozymes from blue-green, red, andgreen algae. Double immunodiffusion in agar indicated that therewas structural similarity in the isozyme from Cyanidium caldarium,the blue-green algae, Oscillaloria princeps, Pleclonema nostocorumand the red alga, Rhodymenia pertusa. Complete fusion of theprecipitin lines was obtained with these algae. However, onlypartial fusion was observed with the a₂ isozymes from Chlorophyceaesuch as Chlorella pyrenoidosa and Spirogyra setiformis. Spurformation on the precipitin lines occurred when the isozymesfrom these algae were tested against the immuneserum. The results were interpreted as indicative of the possible transitionstatus of Cyanidium caldarium between prokaryotic blue-greenalgae and eukaryotic red algae. It would appear that the Chlorophyceaeevolved along different lines from Cyanophyceae than did theRhodophyceae. (Received November 25, 1975; )     

Mechanisms of the acido- and thermophily of Cyanidium caldarium Geitler V. Acid and heat stabilities of soluble proteins

Acid and heat stabilities of water-soluble proteins extractedfrom an acidophilic and thermophilic unicellular alga, Cyanidiumcaldarium, by French pressure cell treatment were investigated.Soluble proteins from Cyanidium were not particularly acid orheat stable compared with those from mesophilic algae such asAnabaena variabilis and Anacystis nidulans. The results suggestthat the acidophilic and thermophilic mechanisms of Cyanidiumcan not be ascribed to the acid and heat stabilities of theproteins in the cells. ¹ Based on a dissertation submitted to the Tokyo MetropolitanUniversity in partial fulfillment of the requirements for thedegree of Doctor of Science. (Received October 24, 1977; )     

UV-B treated algae exhibiting different responses as a food source for Daphnia magna

The response of green algae Scenedesmus quadricauda and Selenastrumcapricornutum to different levels of UV-B radiation was studied.Daphnia magna, the next step in the food web, was fed with UV-Btreated algae. UV-B radiation induced the synthesis of UV absorbingsubstances and photosynthetic pigments, enhanced the level ofrespiratory potential and suppressed growth of the treated algae.Biomass production in S. quadricauda was higher than in S. capricornutum,but the production of photosynthetic pigments and relative amountsof UV absorbing substances as well as respiratory potentialwere more pronounced in S. capricornutum. A short-term feedingexperiment with D. magna showed that in general, females ingestedhigher numbers of cells of algae treated with a high UV-B dose,but the biomass of ingested algae did not differ significantly.The exception was S. capricornutum treated with a high UV-Bdose; a lower biomass was ingested, probably reflecting thesmaller UV-treated cells.     

Effects of nitrogen stressed algae on different Acartia species

We studied the reproductive response of two copepod species,Acartia tonsa and Acartia clausii, fed algae with differentC:N ratios (4.5 and 9.1 molar ratios respectively) in orderto investigate the influence of nutritional imbalances on calanoidcopepods egg production. Adult females were incubated with thecryptophyte Rhodomonas sp. at saturating concentrations. Thealgae were cultured under nitrogen depleted and sufficient conditions.Ingestion rates of the animals fed with different algae andtheir response in terms of egg production and hatching successof the eggs were quantified. Both species produced more eggwhen fed with nitrogen-limited algae. Ingestion rates and egghatching differed between species, but were not significantlyaffected by the quality of the food. The only difference betweenthe two species in their reaction to food quality was that A.tonsa increased the number of resting eggs, whereas no restingegg production was observed in A. clausii when fed with nitrogenlimited algae. These results support the recent suggestion thata moderately high prey C:N ratio (10–15) supports a higheregg production than a C:N ratio substantially <10.     

Compartmentation of Aldolase Isoforms in Maize Leaves

The leaves of maize seedlings contain two principal isozymesof fructose 1,6-bisphosphate aldolase (E.C. 4.1.2.13 [EC] ), one chloroplasticand one cytosolic (Gasperini and Pupillo, 1982). Mesophyll protoplastswere separated from bundle sheath (BS) strands of both light-grownand dark-grown maize leaves. Aldolase isozymes were separatedfrom extracts of chloroplasts, etioplasts, protoplasts and BSstrands by column isoelectric focusing. The major isozyme ofgreen leaves (pI 4.2) was exclusively in BS chloroplasts, andthere was no evidence of other isozymes occurring in BS tissue.The cytosolic isozyme (pI 6.7) was present in protoplasts ofmesophyll cells, where it may limit the synthesis of hexose-phosphates(estimated activity of 9.4 µmol h^–1 g^–1 fr.wt.) together with lower activities of an acidic form (pI 4.6).Etiolated leaves contained significant amounts of the pI 6.7isozyme in both mesophyll and BS cells, but also minor activitiesof one or more acidic forms with pI values of 4.4–4.7(average pI 4.6) which appear to be located partly in BS etioplasts.The main developmental events for maize leaf aldolase afterillumination were a moderate decrease of cytosolic isozyme (pI6.7) which disappears from the BS within hours and a large,gradual increase of the BS plastid isozyme (pI 4.2). The isoformwith a pI 4.6 also increased rapidly to a low, steady activityin greening mesophyll protoplasts. Key words: C₄, fructose 1,6-bisphosphate, aldolase, Zea mays     

The Effect of Available Nitrate and Ammonium-Nitrogen on the Growth of Two Nitrogen-Fixing Blue-Green Algae

The effect of combined nitrogen supplied as nitrate or ammonium-nitrogenon the growth of two nitrogen-fixing blue-green algae, Nostocentophytum and Calothrix scopulorum, has been studied. Thesespecies have been isolated from marine environments. Both algaegrew as vigorously on elemental nitrogen as in the presenceof combined nitrogen. Growth was equal at all levels of nitrate-nitrogenemployed but high levels of ammonium-nitrogen proved inhibitoryor even toxic to the algae. Nostoc was slightly more susceptibleto high ammonium-nitrogen levels than was Calothrix. Increasein pH of the medium from 7.2 to 8.4 increased the toxic effectof ammonium-nitrogen although relative growth at the variouslevels of nitrate-nitrogen was not affected. The results suggestthat the different effects of ammonium-nitrogen on the growthof freshwater and marine blue-green algae may be due in partat least to the different pH levels of freshwater and marineenvironments in which the algae grow, rather than to any inherentdifference between the two groups.     

Comparative feeding ecology of Tropocyclops prasinus mexicanus (Copepoda, Cyclopoida)

The herbivorous and carnivorous feeding biology of Tropocyclopsprasinus mexicanus, an especially small cyclopoid copepod, wasstudied under in situ food conditions in three different lakesand under experimentally augmented food supplies. The mass-specificfood uptake is compared to that of two larger species—Cyclopskolensis and Cyclops vicinus. Under in situ food conditions,T.p.mexicanus depended to a larger extent on algae than invertebrateprey and showed lower mass-specific ingestion rates than thetwo larger species. Daily mass-specific uptake rates for algaeranged between 10 and 24% of its body mass versus 0.7–7%for invertebrate prey. The larger species C.vicinus and C.kolensisingested a total dry mass equivalent to 106% or up to 143% oftheir body mass with algae contributing 66 and 81%. However,under enriched food availability, T.p.mexicanus is able to ingesta biomass equivalent to its body mass, with an algae (54%) andprey (40%) portion similar to that of the larger species. Bodysize appears to be an important factor for the relative importanceof algal versus invertebrate prey for cyclopoid copepods.     

Firefly assay of adenine nucleotides from algae: Comparison of extraction methods

Pools of ATP, ADP and AMP in algae were compared after extractionwith Trisbuffer, ethanol, chloroform, sulfuric acid, trichloroaceticacid and perchloric acid. Experimental organisms were Anacystisnidulans, Euglena gracilis, Chlorella kessleri and Scenedesmusobtusiusculus. Adenine nucleotides were determined by fireflyluciferase assay. Extraction of illuminated algae in situ with the different methodsresulted in great variations in the proportions between ATP,ADP and AMP. The sum of adenine nucleotides varied less. Extractionwith trichloroacetic acid or perchloric acid generally yieldedthe highest energy charge and ATP/ADP ratio. Experiments withilluminated Anacystis and Scenedesmus showed that extractionwith perchloric acid in situ gave higher yields of ATP in theextracts than if samples were withdrawn for extraction (timefor sample withdrawal {small tilde}1 sec). For Anacystis, itwas demonstrated that the extraction methods giving the highestproportions of ATP were suitable for studies on fluctuationsof the adenine nucleotide pools at transitions from dark tolight. ¹ Permanent address: National Defence Research Institute, Department4, S-172 04 Sundbyberg, Sweden. (Received September 4, 1978; )     

Lipid Metabolism in the Brown Marine Algae Fucus vesiculosus and Ascophyllum nodosum

Lipid metabolism and environmental effects on this process havebeen studied in the marine brown algae Fucus vesiculosus andAscophyllum nodosum. These algae showed very similar patternsof lipid metabolism during 24 h incubations. Labelling from[1-¹⁴C]acetate showed the major labelled lipids to be the ß-alanineether lipid and the neutral lipid fraction in both algae. Ofthe glycolipids, only sulphoquinovosyldiacylglycerol was welllabelled and the phosphoglycerides were all poorly labelled.The major labelled fatty acids were palmitate and oleate, againin both algae, although Fucus vesiculosus also showed significantlabelling of stearate and behenate. Although the amount of fattyacid labelling increased with time, the proportion of labelin palmitate and oleate remained approximately constant. Verylong chain fatty acids (arachidic, behenic) were increasinglylabelled with time. Lowered incubation temperatures decreased labelling of the saturatedfatty acids. Cu²⁺ increased the proportion of oleate labelledin both algae, and of linoleate in Fucus vesiculosus. This cationdecreased the percentage labelling of stearate and myristatein Ascophyllum nodosum. Lipid metabolism in Ascophyllum nodosumwas more sensitive to raised Cu²⁺ levels than in Fucus vesiculosus Key words: Acyl lipid metabolism, Fucus vesiculosus, temperature effects, Ascophyllum nodosum, copper pollution     

Isozyme and RAPD Analysis of the Genetic Diversity Within and BetweenVigna luteolaandV. marina

Nineteen accessions ofVigna luteola,five ofV. marinassp.oblonga,and two ofV. marinassp.marinawere analysed using variation ofisozymes and RAPD markers to obtain better insight into geneticrelationships within and between these taxonomic entities. Thirteenputative isozyme loci were scored, seven of which were polymorphic.Both species showed very low genetic diversity indices and mostof the variation was detected among populations. Pairwise Nei'sgenetic distances based on allozyme frequencies were also verylow and the accessions ofV. marinassp.marinawere the least relatedto the others. RAPD analysis was more discriminating and 66bands out of a total of 85 were polymorphic. Based on the presenceor absence of bands, Jaccard's similarity index was calculated.Similarity ranged from 0.476 to 0.98. Matrices derived fromboth isozyme and RAPD data were used to construct UPGMA dendrograms.In the tree obtained from Nei's genetic distance, based on allozymefrequencies, accessions belonging toV. marinassp.oblongaweremixed withV. luteolaaccessions; on the other hand, the twoV.marinassp.marinaclustered separately, with oneV. luteola.Thedendrogram derived from RAPD data showed three main groups correspondingto the three taxa analysed. Moreover, according to these data,V.marinassp.oblongais more closely related toV. luteolathan toV.marinassp.marina.Copyright 1997 Annals of Botany Company Vigna luteola(Jacq.) Benth.; Vigna marina(Burm.) Merrill; isozymes; RAPDs; genetic relationships; genetic variation     

COMPARATIVE STUDIES OF PHOTOCHEMICAL OXIDATION-REDUCTION REACTIONS IN LAMELLAR FRAGMENTS OF VARIOUS ALGAE AND SPINACH

The activity of various electron carriers, including DPIP, spinachplastocyanin, mammalian cytochrome c, and Anabaena cytochrome553, as donor in the reaction induced by the photochemical systemI was examined with lamellar fragments of various algae andspinach. Reduced DPIP was an effective electron donor irrespective ofthe organisms, when it was supplied at a high concentration(10^–3 M). Spinach plastocyanin was effective in the reactionswith the lamellae of green algae, Euglena, diatom Phaeodactyrumand red algae Porphyra yezoensis and Porphyra sp. Yamamoto II,whereas it was inactive in the lamellae of blue-green algae.Horse-heart cytochrome c and Anabaena cytochrome 553 were activein the reaction with the lamellae of bluegreen algae. The formercytochrome was also active in the reactions in Porphyridiumand Cyanidium. The cytochromes were less active in the reactionsin which spinach plastocyanin acted as effective electron donor. The data were interpreted as that the photochemical system Iin bluegreen algae differs from that of other photosyntheticorganisms with respect to the properties of the site of theelectron-input. ¹ Present address: Nomura Research Institute for Technologyand Economics, Kamakura, Kanagawa. ² Present address: Ocean Research Institute, University of Tokyo,Nakano, Tokyo.     

Fixation of Elemental Nitrogen by Marine Blue-green Algae

Three blue-green algae, Calothrix scopulorum, Nostoc entophytum,and Oscillatoria brevis, isolated from the upper littoral andsupralittoral fringe of the sea-shore were obtained in pureculture and tested for fixation of elemental nitrogen. Appreciablefixation by Calothrix and Nostoc was detected, a proportionof the total nitrogen fixed being liberated into the culturemedium. There was no evidence of fixation by Oscillatoria. Thisappears to be the first evidence that blue-green algae isolatedin pure culture from marine habitats fix nitrogen.     

DISTRIBUTION OF QUINONES IN SOME PHOTOSYNTHETIC BACTERIA AND ALGAE

The distribution and the concentration of quinones in 5 speciesof photosynthetic bacteria and 4 species of algae were investigated.The Athiorhodaceae, except for Rhodospirillum rubrum, containedubiquinone as the major quinone component. Rhodospirillum rubrumcontained two kinds of quinones, i.e. ubiquinone and rhodoquinone.Chromatium, strain D contained two kinds of quinones, i. e.ubiquinone and vitamin K₂. The green sulfur bacterium, Chloropseudomonasethylicum, contained vitamin K₂ and a Chlorobium quinone-likesubstance. The marine algae tested, Porphyra yezoensis, Porphyra sp. andHizikia fusiforme, contained vitamin K₁, plastoquinone A, -tocopherylquinoneand ubiquinone. In Chondrus ocellatus, the presence of a ubichromenol-likesubstance was detected instead of ubiquinone. Other types ofplastoquinone and tocopherylquinone were not found in thesealgae. In the thalli of Porphyra sp., vitamin K₁, plastoquinoneA and -tocopherylquinone were found to be localized in chloroplasts. ¹Present address: Department of Biophysics and Physical Biochemistry,Johnson Research Foundation, University of Pennsylvania, Philadelphia,Pennsylvania, U.S.A.     

Daphnids respond to algae-associated odours

Using a Y-tube olfactometer, it was found that Daphnia galeatax hyalina moves to the arm with odour from either of two ediblealgal species (Scenedesmus acuminatus and Oscillatoria limnetica)rather than to the alternative arm with clean water. However,no differential response was observed when odours of the toxiccyanobacterium (Oscillatoria agardhu) were tested. We suggestthat odours associated with edible algae attract Daphnia whereasnon-edible algae do not elicit attraction of Daphnia.     

The influence of food resources on the development, survival and reproduction of the two cyclopoid copepods: Cyclops vicinus and Mesocyclops leuckarti

Laboratory experiments were conducted to determine whether thetwo cyclopoid copepods. Cyclops vicious and Mesocyclops leuckaru.exploit the same food resources. The food requirements of juvenilesof the two cyclopoid copepods were investigated. Moreover, theimportance of algae for the predaceous adults was studied. Naupliiof both M leuckaru and C.vicinus successfully developed intocopepodites when fed the motile algae Chlamydomonas reinhardtii.Chlamydomonas sphaeroides and Cryptomonas sp. Threshold foodconcentrations for naupliar development varied between offeredalgae and between the two cyclopoid species. The food thresholdfor successful naupliar development, when reared on C.reinhardui,was lower for M.leuckarti (0.3 mg C 1^–1) than for C.vicinus(0.5 mg C l^–1) whereas a similar food threshold was foundusing Cryptornonas sp (0.3 mg C ^–1) and C.sphaeroides(<0.2 mg C 1^–1), Naupliar development time was inverselyrelated to food concentration. Food required for copepoditedevelopment differed for the two cyclopoid species. Cyclopsvicinus was able to develop to the adult stage on a pure dietof any one of the three algal species. whereas M.leuckarti requireda prey supply of the rotifer Brachionus rubens. Food composition.i.e. algal species, algal concentration and rotifer abundance,influenced copepodite survivorship of both cyclopoids and wasalways higher in the presence of B.rubens. Under similar foodconditions, mortality was higher for M.leuckarti than for Cvicinus. Mesocyclops leuckaru females were very dependent onanimal food. The predation rate of M.leuckaru was not lowerin the presence of algae. Egg production of M.leuckarti waslow on a pure algal diet and significantly higher when B rubenswas present. The results were used to discuss the life cyclestrategy and the possibility of exploitative competition ofthe two cyclopoid copepods.     

Remote detection of algae by copepods: responses to algal size, odors and motility

Selective feeding on large algae by copepods involves remotedetection of individual particles and subsequent active captureresponses In this study we use radiotracer experiments to quantifythe clearance rates of five coexisting freshwater copepods andto investigate the relative merits of the chemoreception andmechanoreception hypotheses of remote detection Tropocyclopsand three diaptomid copepods exhibited relatively high clearancerates when feeding on low concentrations of large algae, suggestingthat most previous studies with freshwater copepods have underestimatedmaximal clearance rates and the degree of size selectivity.All five species of copepods exihibited strong selection foran intermediate-sized flagellate (25 µm Cartena) or alarge-sized nonmotile alga (80 µ.m Pediastrum) over asmall-sized flagellate (6 µ.m Chlamydomonas). The weight-specificclearance rate for Tropocylops prasmus feeding on motile Cartena(271 ml mg^–1 h^–1) was about twice that of threediaptomid copepods and more than an order-of-magnitude higherthan the estimate for Epischura lacustris feeding on its preferredalga, Pediastrum Assuming that distance chemoreception (‘smell’)is important in remote detection, we predicted that the additionof high concentrations of ‘algal odors’ would obscureany chemical gradients emanating from individual algal cellsand would thereby hinder the remote detection and active captureof large algae Contrary to this hypothesis, the addition ofamino acids, sucrose, and algal extracts had no effect on theclearance rates and selectivity of Diaptomus birgei. These results,together with recent cinematographic studies (Vanderploeg etal.,1990), suggest that mechanoreception is the primary mechanismfor the remote detection of large particles by diaptomid copepods.A raptorial cyclopoid, Tropocyclops prasinus, exhibited strongpreferences for motile algae, whereas a suspension-feeding calanoid,D birgei, did not select between motile and nonmotile cells.Motility appears to be an important factor in algal detectionfor small cyclopoid copepods but not for suspension-feedingdiaptomids     

Characterization of {beta}-amylase isozymes in soybean seeds by isoelectric focusing

Distributions of the isozymes of ß-amylase [EC 3.2.1.2 [EC] ]in seeds of the cultivated soybean, Glycine max, the semicultivatedtype, Glycine gradlis, and the wild type, Glycine ussuriensis,were studied by the isoelectric focusing method. Four isozymes(1 to 4) were found in seeds of the soybean and related species;their respective isoelectric points were 5.12, 5.25, 5.38 and5.52?0.02. Crystalline components I and II described in a previouspaper corresponded to isozymes 2 and 4, respectively. Each varietyor species of soybean contained one or two isozymes, the typeof isozyme pattern being characteristic of the variety of soybeanand the related species. Taxonomically, the isozyme patternsseem to correlate pardy with some morphological features, e.g.the determinate growth habit, the semitwinning property of thestem and the color of the seed episperm. (Received January 9, 1979; )     

Changes in the Levels of Ribulose-l,5-bisphosphate Carboxylase/Oxygenase (Rubisco) in Tetraedron minimum (Chlorophyta) during Light and Shade Adaptation

Exponentially growing cultures of the chlorophyta Tetraedronminimum were allowed to photoadapt to low (50µmole quantam^–2s^–1) and high (500µmole quanta m^–2–1)irradiance levels. In these cultures, various aspects of theorganization of the photosynthetic apparatus and related differencesin its performance were studied. In this organism, the observed five-fold increase in pigmentationof low-light adapted cells was due to increases in the numbersof PSU's, while their sizes remained constant. Using radioimmunoassay technique, we found that high-light adaptedalgae had over five times more Rubisco per PSU than their low-lightadapted counterparts. The high-light adapted algae also exhibited far higher (x2.3)light saturated photosynthetic rates per chl a. This increasewas the result of a reduction of tau, , the turnover time ofPS II reaction centers. We propose that the increase in Rubisco per PSU in high-lightadapted algae explains the reduction in , which results in thehigher P_max rates per chl a in these algae. The relationship is non linear, since the increase in Rubiscoper PSU was x5.3 whereas that in P_mM per chl a was only x2.3. (Received July 30, 1988; Accepted December 2, 1988)     

Evidence for a Structural Role of Protein in Algal Cell Walls

Load-extension measurements were made on three filamentous algaebefore and after either digestion with proteolytic enzymes ortreatment with dithiothreitol. Large differences in tensileproperties of the walls were observed, particularly after pronasedigestion, in two algae, Cladophora and Chaetomorpha, whichcontain hydroxyproline in the wall. Pronase had little or noeffect on a third alga, Nitella, lacking hydroxyproline. A smallerdifference was found on treatment with dithiothreitol, a specificreducing agent for disulphide bonds. These results suggest thata hydroxyproline containing protein is a structural componentof these algal walls, and that hydroxyproline itself is involvedin the carbohydratepeptide linkage.     

The b.e. and Q types of 1,4-α-d-glucan: 1,4-α-d-glucan-6-glucosyltransferase isozymes in algae

The branching isozymes of the red alga, Rhodymenia pertusa are of two types: Q, which can branch, via the synthesis of α-1,6-glucosyl linkages, linear amyloses to amylopectin; and b.e., which can further branch the amylopectin formed to the more highly-branched floridean starch. Using the technique of tandem crossed-immunoelectrophoresis, it is shown that the Q branching isozyme of the red alga is more closely related to the b.e. type of branching isozymes of Anacystis nidulans and Cyanidium caldarium than it is to the exclusively Q types of branching isozymes found in Chlorella pyrenoidosa and other chlorophytes. The possibility of a biphyletic evolution of the red and the green algae from blue-green ancestral forms is discussed.