Physiology and Cultivation of Algae and Cyanobacteria 2. Summaries of the ten algal divisions • Historically – classified on basis of: pigmentation, chem. structure of storage products, thylakoid membrane organization, chemistry, structure of cell wall, number, arrangement, and ultrastructure of flagella, occurrence of special features, sex.cycles • Recently – comparison of sequence of 5S; 18S; 28S rRNA, internal genetic coherence Cyanophyta – together with prochlorophyta – non-motile G- eubacteria • 1-cell. to filament (un-/branched), & colonial aggr. • widely distrib.; planctonic, blooms, picoplancton, benthic, soil, mud, hot springs; symbiotic • Pigm.: chl a, blue & red phycobilins, carotenes • phycobilisomes in rows on outher surface of thylakoids • Thylacoids – free in cytoplasm, non-stacked, singled&equidistant • Res.polysach.: cyanophycean starch (granules betw. thylakoids), cyanophycin • some marine contain gas vesicles • some filamentous form heterocysts & akinetes • some produce hepato-, neurotoxins Prochlorophyta • 1-cell. / filamentous (un-/branched) • free-living component of pelagic nanoplancton, obligate symbionts within didemnid ascidians & holoturians • mainly limited to tropical&subtropical env. • Pigm.: chl a, chl b, -carotene, xanthophyls lack phycobilins, • Thylakoids – free in cytoplasm, stacked • Res.polysach.: cyanophycean starch (starch-like) Cyan.&Prochlor. • able to fix nitrogen • contain polyhedral bodies (carboxysomes) with RuBisCO • in cell wall peptidoglycane layer • obligate photoautotrophs • asexual reproduction (cell division / fragmentation of colonies) Glaucophyta • 1-cell., flagellate, dorsiventral construction, 2 unequal flagella inserted in shallow depression below apex • marine, rare freshw., solme soil • Pigm.: chl a, acces.pigm.: phycoerythrocyanin, phycocyanin, allophycocyanin in phycobilisomes, carotenoids • Chlpl. lie ni spec. vacuole, present thin peptidoglycan wall betw. 2 outher plastid membranes • Thylacoids non-stacked • ctDNA in center of chlpl. near carboxysomes (RuBisCO) • Res.polysach.: starch (granules in cytoplasm outside of chlpl.) • photoautotrophs with blue-green plastids – cyanelles – presumed to be phylogenetically derived from endosymbiotic cyanobacterium • unknown sex. reproduction Glaucocystis sp. / from Kanazawa, Ishikawa Pref., Japan / Microscope:Leica DMRD (DIC) Rhodophyta • red algae, mostly seaweeds, can free-living 1-cell. • mostly marine • lack flagellate stages • Pigm.: chl a, phycobiliproteins in phycobilisomes • Chlpl. 2-membrane enclosure • thylakoids – non-stacked, single&equidistant within chlpl. • ctDNA scattered throughout chlpl. • Res.polysach.: floridean starch & -1.4-glucan polysach. – grains in cytoplasm • mostly photoautotrophs • Repr. – in majority – cytokinesis incomplete >> pit connection >> proteinacous plug >> plug – sexual.: isomorphic / heteromorphic diplohaplontic life cycle Rhodophyllis Divaricata - http://www.algaebase.org/search/species/deta il/?species_id=121 Heterokontophyta • when 2 flagella they are different • flagelate cells – heterokont – long mastigonemate flagellum directed forward during swimming & short smooth fl., points backwards along the cell • 1-cell-to-colonial, filamentous, siphonous, multicellular complex kelp; various type of flagellum • mostly marine (can freshw,&terestrial) • Pigm.: prepoderance of carotenoids over chlorophylls – chl a, c1, c2, c3, access.: b-carotene, fucoxanthin, vaucheriaxanthin • thylakoids stacked in three – lamellae • one lamellae usually runs along whole chlpl. = girdle lamellae • chlpl. 2-membrane & fold of ER • ctDNA – ring-shaped • Res.polysach.: chrysolaminarin in cytoplasm in spec. vacuole • eyespot – layer of globules, enclosed within chlpl. together with photoreceptor loc. in smooth flagellum, forms photoreceptive apparatus • photoautotrophy can be combine with heterotrophy • sex. reproduc.: life cycle – haplontic (Chrysophyceae), diplontic (Bacillariophyceae), diplohaplontic (Phaeophyceae) http://www.urbanrivers.org/drawingdiatoms/diat oms.html http://oceandatacenter.ucsc.edu/PhytoGallery/dinos%2 0vs%20diatoms.html http://www.calacademy.org/science_now/archive/ academy_research/sarah_spaulding.php Haptophyta • mostly 1-cell., motile, palmelloid / coccoid (rare colonial/filament.) • generaly marine • flagellate cells – 2 naked flagella inserted laterally or apically (may have diff. lenght) • haptonema – typically long organelle flagellar structure (diff ultrastruct.) • Pigm.: chl a, c1, c2, access.: fucoxanthin, -carotene, xanthins • Chlpl. enclosed within fold of ER • Thylakoids – stacked in three, no girdle lamellae • ctDNA – nucleoid scattered in chlpl. • can be eyespot – row of globules inside chlpl., no associated flagellar struct. • Res.polysach.: chrysolaminarin • Cell surface – tiny celulosic scales or calcified scales bearing spoke-like fibrils • Phototrophs / heterotrophs, phagotrophy in forms that lack cell covering • Sex. reprod.: heteromorphic diplohaplontic life cycle Cryptophyta • 1-cell. flagellate • assymetric cells, dorsiventrally constructed • 2 unequal hary flagella, subapically inserted, emerging from above gullet loc. on ventral side of cell – lined by ejectosomes • free-swimming in freshw. & marine • Pigm.: chl a, c2, phycobilins in thylakoid lumen > in phycobilisomes • Chlpl. – 1 - 2 per cell, surrounded by fold of ER - in these intermembrane space – peculiar organemme – nucleomorph - ? nucleus of red algal symbiont • Thylakoids in pairs, no girdle lamellae • Pyrenoid projects out from the inner side of chlpl. • ctDNA condensed in small nucleoid inside chlpl. • Res.polysach.: starch ganules in periplastidial space • eyespot sometimes inside plastid, no association with flagella • Cell enclosed in stiff, proteinaceous periplast – polygonal plates • mostly photosynthetic nutrition, can be heterotrophs • Repr.: primary longitudinal cell division, can be sexual Dinophyta • 1-cell., flagelates (can be ameboid, coccoid, palmelloid or filament.) • 2 flagella with independent beating pattern (1st - training, 2nd - girdling) >> rotatory whirling motion • characteristic cell covering components beneath cell membrane (layer of flat, polygon. vesicles – empty or celulose filled) • dinokont type – theca – bi-partite armor (upper, anterior [epiconus]; lower, posterior [hypoconus]) separated by groove (cingulum) loc. transversal flagellum; smaller groove (sulcus) – extended posteriorly – host longitudinal flagellum • important freshw. & marine microplancton • consumed by filterfeeders; parasites; endosymbionts of tropical corals • Pigm.: chl a, b, c1, c2, fucoxanthin, carotenoids, xanthophylls • Chlpl. (if present) surrounded by 3 membranes • Thylakoids stacked in 3; ctDNA in small nodules scattered in whole chlpl. • complex photoreceptive system “compound eye” (Warnowiaceae) – lens & retinoid • Dinocaryon – eukaryotic nucleus, chromosomes condensed during mitosis, karyotheca unbroken – endomitosis • Res.polysach.: starch - grains in cytoplasm; oil droplets in some genera • At cell suraface – trichocysts – discharge explosively when stimulated • Photoautotrophy & hi. diversity of nutrit. types • can form blooms, possib. bioluminiscence • Sex. reproduct. – haplontic life cycle; can form hypnospores A marine dinoflagellate. (Bar: 30 mm.) Dorsal view of Gonyaulax sp., a brackish water dinoflagellate. Euglenophyta • mostly unicell.flagellates, can be colonial • widely distributed, freshwater, brakish & marine, abundant in hi. heterotrophic env. • flagella arise from bottom of cavity – reservoir (loc. in anterior end of cell); can live in mud; presence of pellicle – proteinaceous wall inside cytoplasm – spiral construction • Pigm.: chl a & b,  & -carotenes, xanthins, some spec. can absent plastids • Chlpl.- 3 membrane envelope • Thylakoids – group of three without girdle lamella • photoreceptive system – orange eyespot loc. free in cytoplasm; true photoreceptor loc. at base of flagellum • Res.polysach.: paramylon (-1,3-glucan); granules inside cytoplasm(not in chlpl.) • obligate mixotrophs, require vitamins of B group; colorless can be phagotrophs, osmotrophs • Reproduction – only asexual Unicell of Euglena mutabilis. (Bar: 10 mm.) Chlorarachniophyta • naked, unicell., form net-like plasmodium via filopodia • life cycle forms – amoeboid, coccoid, flagellate stages • ovoid zoospores bear single flagellum • marine • Pgm.: chl a & b • Chlpl. – 4-membrane envelope, each has prominent projecting pyrenoid • Thylakoids – stacked in one to three • nucleomorph present btw. 2nd and 3th membrane originated from green algal endosymbiont • Res.polysach.: paramylon (-1,3-glucan) • phototrophs & phagotrophs engulfs bacteria, flagelates & eukaryotic algae • Repr. – mostly asexual – mitosis or zoospore formation – heterogamy rarely Plasmodial reticulum of Chlorarachnion, bright field microscope image (a) and schematic drawing (b). (Bar: 4 mm.) Chlorophyta • great range of somatic differentiation (flagellates to differentiated multicell. thalli) • thallus organization <--> basis of classification • flagella -wide diversity in number & arrangement (1-8 in apical / subapical region) • zoids are isokont (similar struct. but can differ in lenght) • freshwater, marine & terestrial • Pigm.: chl. a & b,  & -carotenes, xanthophylls • Chlpl. – 2-membrane envelope • Thylakoids – stacked, form grana • pyrenoid (if present) in chlpl. • ctDNA – circular • Res.polysach.: starch – most important – grain inside chlpl. • glucan & -1,4-mannan can present in cell wall • eyespot (if present) loc. inside chlpl. • photoautotrophs, can be heterotrophs • Repr. – sex. – variety of life cycle – group specific – similarity to higher plants - Trentepohliaceae – cell division using phrogmoplast disc where the cells will divide • probably land plants derived directly from these freshwater algae Unicell of Pyramimonas longicauda. Filament of Oedogonium sp., with a Peranema sp. cell. (Bar: 20 mm.) Thallus of Codium sp. (Bar: 2 cm.) Thallus of Trentepohlia arborum. Thallus of Nitella sp. Portion of the thallus of Acetabularia sp. Endosymbiosis & origin of eukaryotic algae • procaryotic ancestor → endosymbiotic events → primary plastid • secondary / tertiary endosymbiosis → plastid (sec. eukaryotic cell) • arrangement of cellular compartments inside the the other – info about evolut. history • Cyanobacteria – evolved >2.8 bill. years ago – fundamental roles in ocean carbon, oxygen, nitrogen fluxes – turning point in biogeochemistry of Earth – photosynthesis – energy of VIS, oxidation of H2O, reduction of CO2 – CO2 + H2O + light chl a> (CH2O)n + O2 Three major algal lineages of primary plastids • Glaucophyta lineage – plastids – thin peptidoglycan cell wall & cyanobacter.-like pigments » cyanobacterial ancestry – neither green nor red plastid present – any secondary plastid derived from Glacophyta is known • Chlorophyta lineage “green algae” – green algal plastid – 2-membrane system surround. • chl b – sec. pigment, phycobiliproteins lost – other – prochlorophyte based hypothesis – major role in oceanic food webs & carbon cycle from -2.2 bill. years until Permian extinction (-250mil y.) – origin of land plants – >Secondary endosymbiosis → Euglenophyta (3-membrane plastid) & Chlorarachniophyta (4-membrane plastid • Rodophyta leneage “ red algae” – red algal plastid – 2-membrane system • chl a & phycobiliproteins organized into phycobilisomes attached on thylakoid membrane • Thylakoids with phycobilisomes don’t form stacks – similar to cyanobacteria – >Secondary endosysmbiosis → Cryptomonades (Cryptophyta) • (4-membrane plastid) + chl c (also Haptophyta, Heterocontophyta & Dinophyta) – stacked thylakoids found in lineages lacking phycobilisomes – >a few groups of Dinoflagelates Tertiary endosymbiosis – uptake of secondary plastid containing endosymbiont – All these groups are relatively modern org. – dinoflagelates & coccolithophorids rise paralel with dinosaurs – diatoms rise with mammals members of red lineages in shallow seas in Jurassic period provide petroleum Endosymbiosis & origin of eukaryotic algae Chlorophyll a,b Chlorophyll a,b Chlorophyll a,b Chlorophyll a,b Chlorophyll a,d Chlorophyll a,c Chlorophyll a,c Chlorophyll a,c Chlorophyll a,c