STRUCTURE AND SIGNIFICANCE OF THE CRYPTOMONAD FLAGELLAR APPARATUS. I. CRYPTOMONAS OVATA (CRYPTOPHYTA)1

The absolute configuration of the flagellar apparatus in Cryptomonas ovata has been elucidated and found to be similar to that reported for Chilomonas paramecium. Variations apparent in the flagellar apparatus of Cryptomonas ovata include the presence of striations in the mitochondrion associated lamella, a rhizostyle which does not bear wing-like extensions from the microtubules and does not lie close to the nucleus, and a striated fibrous anchoring structure associated with one basal body which has not hitherto been described. The flagellar apparatus also includes a four stranded microtubular root which traverses into the anterior dorsal lobe of the cell, a striated fibrous root which is associated with a five stranded microtubular root, and a two stranded Cr root. The homologous nature of these roots to those in the larger cryptomonads is discussed in relation to the apparent reduction in flagellar apparatus size and complexity among the smaller cryptomonads. A diagrammatic reconstruction of the flagellar apparatus of Cryptomonas ovata is also presented.     

Cytokinesis inCryptomonas ovata (Cryptophyceae)

Summary We describe the pattern of cytokinesis inCryptomonas ovata. Cell division begins at the posterior of an enlarged cell and proceeds through the gullet and between four active flagella. This pattern of cytokinesis inCryptomonas ovata differs from that previously described for other cryptomonads and might be of importance in establishing taxonomic affinities for the group.     

Comparison of phycoerythrins (542, 566 nm) from cryptophycean algae

Summary The phycoerythrins from Rhodomonas sp. strain 3-C and Cryptomonas ovata var. palustris were purified and partially characterized. The phycoerythrin from Rhodomonas had a single visible absorption maximum at 542 nm with a shoulder at approximately 562 nm and is, therefore, representative of cryptophyte type I phycoerythrin. The phycoerythrin from C. ovata var. palustris had a single absorption maximum at 566 nm and is, therefore, representative of cryptophyte type III phycoerythrin. Calibrated gel filtration chromatography showed that both of these phycoerythrins have a native molecular weight of 30 800 daltons. Calibrated sodium dodecyl sulfate gel electrophoresis demonstrated that both pigments were composed of two subunits with apparent molecular weights of 17 700 and 11 000 daltons. On polyacrylamide gel electrofocusing both these phycoerythrins had an isoionic point of 4.90.     

How diverse are planktonic cryptomonads in Brazil? Advantages and difficulties of a taxonomic-biogeographical approach

We compare ‘temperate data’ with information contained in 49 surveys of cryptomonads from Brazilian tropical regions. These surveys contain a total of 351 records relative to a total of 38 taxa at the species level or below. All taxa were identified using traditional morphological characters visible with the light microscope. Two taxa appear to be new species, and amongst the known species Cryptomonas erosa Ehrenberg is the most frequently recorded one. To date two species of Pseudocryptomonas Bicudo & Tell (all containing multiple photosynthetic endosymbionts/chloroplasts) and the species Cryptomonas brasiliensis Castro, C. Bicudo & D. Bicudo have not been found outside Brazil. With respect to their geographical distribution in Brazilian tropical regions, cryptomonads are better represented in reservoirs and coastal lagoons located in the south-eastern part of the country. Some species appear to be restricted to brackish coastal ecosystems (oligo- to mesohaline and meso- to eutrophic waters). There are only four records of marine cryptomonads. A comparative study of three different kinds of shallow aquatic environments in Brazil – north-eastern reservoirs, a flood-plain Amazonian lake, and brackish lagoons on the south-eastern coast – shows that cryptomonads are to be found constantly, and their species number density, and biomass are generally low (usually <10%) in relation to the other phytoplankton. The case of Plagioselmis Butcher emend. Novarino, Lucas & Morrall, amongst others, exemplifies the great difficulties encountered while attempting to interpret biogeographical information based on light microscopy within the context of a modern systematic and taxonomic framework based on electron microscopy.     

武汉东湖隐藻门植物的分类学研究

隐藻门植物在各种淡水水体中很常见,其中卵形隐藻、啮蚀隐藻在国内被多次报道过。但是由于缺乏分类学的资料,国内关于隐藻门植物的报告并不完全准确,其类群也常常被忽视。我们在2009年6月到2010年3月间,不定期从武汉东湖的各个区域采集水样,共鉴定隐藻门植物4属8种：卵形隐藻、啮蚀隐藻、蛋白核隐藻、四蛋白核隐藻、马索隐藻、反曲弯隐藻、犀角织隐藻、具尾逗隐藻。其中四蛋白核隐藻和犀角织隐藻为中国新记录。作为具尾逗隐藻的异名,尖尾蓝隐藻此前也曾在国内被报道。     

A comparative study of periplast structure inCryptomonas cryophila andC. ovata (Cryptophyceae)

Summary Freeze-fracture followed by deep-etch was used with transmission electron microscopy to characterize and compare the periplasts of two cryptomonads,Cryptomonas ovata andC. cryophila. The periplast ofC. ovata consists of a dense surface mat of granular/fibrillar material overlying a series of polygonal plates attached to the undersurface of the plasma membrane (PM) at their upturned edges. Fracture faces of the PM reveal a highly stable substructure with distinct patterns of intra-membrane particles (IMPs) associated with the underlying plates; a role for the PM in plate development is indicated. The surface periplast component ofC. cryophila exhibits a cover of morphologically complex, overlapping heptagonal scales (termed rosette scales) in addition to elongate fibrils. The arrangement of IMPs within the PM is predominantly random and the inner periplast component consists of a sheet with regular pores where ejectisomes are located. The sheet does not appear closely associated with the PM. The combination of features exhibited by the periplast ofC. cryophila warrants its inclusion as a new type within theCryptophyceae.     

LIGHT-DEPENDENT GROWTH, DARK SURVIVAL, AND GLUCOSE UPTAKE BY CRYPTOPHYTES ISOLATED FROM A FRESHWATER CHEMOCLINE

Clones of Cryptomonas phaseolus Skuja , Cryptomonas rostratiformis ( Skuja ) Skuja in Huber-Pestalozi, and Cryptomonas undulata Gervais were isolated from the deep chlorophyll maximum near the oxic/anoxic boundary layer of the mesoeutrophic lake Schlachtensee, Germany. Different autecological features of these species were studied in batch culture experiments . Cryptomonas cf . ovata Ehrenberg and Chroomonas sp. that never dominated in the deep chlorophyll layer were also isolated from Schlachtensee to study their light-dependent growth in comparison to the deep-living species . Cryptomonas undulata, C. cf . ovata, and C. phaseolus had a very low light compensation point ( 5–7 μmol.m^-2.s^-1 ), whereas the growth rate of Chroomonas sp. and C. rostratiformis was positive above 16 and 24 μmol.m^-2.s^-1 . Cryptomonas phaseclus and Chroomonas sp. became photoinhibited above photon flux densities of 92 and 116 μmol.m^-2.s^-1 . Cryptomonas rostratiformis, C. cf . ovata, and C. undulata reached a maximum growth rate at a considerably higher photon flux density (198–250 μmol.m^-2.s^-1 ). Cryptomonas phaseolus grew fastest under light-limiting conditions . Chyptomonas phaseolus and C. undulata were best able to suruive prolonged periods of darkness . Cryptomonas phaseolus, C. rostratiformis, and C. undulata did not show any uptake of fluorescent latex beads. When labeled glucose was provided in naturally occurring concentrations, carbon uptake by C. phaseolus, C. rostratiformis, and C. undulata was negligibly small in comparison to cellular carbon content. I suggest that the adaptation to a low-light environment is an important preadaptation for the dominance of C. phaseolus and C. undulata near the freshwater chemocline .     

Effects of prey type on suspension-feeding behavior in Nile tilapia

Using freshly collected field samples and enrichment cultures, eight genera of cryptomonads from the Salton Sea are recorded for the first time. Comparative data from light and scanning electron microscopy were utilized to identify these genera and species. The genera included Chroomonas, Falcomonas, Hemiselmis, Plagioselmis, Pyrenomonas/Rhodomonas, Storeatula, Teleaulax, and the kathablepharid Leucocryptos. One putative genus remains unidentified and may represent a new taxon. SEM has not been conducted on this cryptomonad, but it has been isolated and is being maintained in culture. The genera and species identified from the Salton Sea are typical of marine rather then freshwater environments and may play an important role in primary productivity and as preferred food organisms for zooplankton.     

Periplast development in Cryptophyceae II. Development of the inner periplast component inRhinomonas pauca,Proteomonas sulcata [haplomorph],Rhodomonas baltica,andCryptomonas ovata

Summary The inner periplast component (IPC) of numerous cryptomonads is composed of discrete inner plates, situated beneath (and intimately associated with) the plasma membrane (PM). Freeze-fracture images reveal that the PM is organized into a series of ordered structural domains, which directly correspond in size and shape to the underlying inner plates. Freeze-fracture images are used here to compare IPC arrangement inRhinomonas pauca, Proteomonas sulcata [haplomorph],Rhodomonas baltica, andCryptomonas ovata, and to examine development of inner plates in these cryptomonads. In all genera examined, the IPC is highly ordered across most of the cell periphery but appears to be modified adjacent to the vestibulum and mid-ventral line, which represent the anamorphic zones. Variations in the size and shape of PM domains in these regions suggest that development of the IPC occurs within anamorphic zones, by the de novo formation and enlargement of inner plates throughout the cell cycle.     

Carotenoids of cryptophyceae

The carotenoids of selected Cryptophyceae, Rhodomonas D3 and Cryptomonas ovata, have been examined by methods including HPLC, mass spectrometry ¹H NMR and circular dichroism. $\text{3′R,6′R-}\text{Chirality}$ has been assigned to monadoxanthin from ¹H NMR and CD data; β,?-carotene possessed the common $\text{6′R-}\text{chirality}$. The quantitative distribution pattern of carotenoids in Cryptophyceae established here and previously, totalling five species' is discussed in chemosystematic context. β,?-Carotene (3–8% of total) is the major carotene, accompanied by ?,?-carotene (0.2%), β,β-carotene (0–1%) and lycopene (0-trace). Zeaxanthin (2%) was identified in C. ovate. The diacetylenic alloxanthin is the major carotenoid (70–88%), and the monoacetylenic crocoxanthin (5–15%) and monadoxanthin (0–16%) less abundant. No epoxidic or allenic carotenoids could be detected. The biosynthetic precursor of acetylenic carotenoids in this primitive algal class is discussed. The significance of Cryptophyceae in the marine food chain is commented on, using alloxanthin as an indicator.     

The effect of constant darkness and short light periods on the survival and physiological fitness of two phytoplankton species and their growth potential after re-illumination

We tested the survival potential and fitness of two different algae strains (the diatom Thalassiosira weissflogii and the cryptophyceae Rhodomonas sp.) under different growth conditions (complete darkness and short light intervals, simulating conditions in a deep mixed water column) at different temperatures, plus the effect of these conditions on the physiological fitness and growth after re-illumination was examined. Both species survived the experimental conditions without significant cell loss or physiological damage. Two different survival strategies were observed: (1) the diatom T. weissflogii immediately reduced its metabolic rate and stopped cell division. The effect on chlorophyll a (chl-a) content and photosynthetic capacity was negligible. At 10 °C, T. weissflogii used the short light windows to metabolize carbohydrates and growth. (2) The cryptophyte Rhodomonas sp. initially continued to grow after transfer into all trials. However, the cell number decreased after day 6. Carbohydrate and chl-a content went on to decrease dramatically (70 and 50%, respectively). After 3 days of re-illumination, T. weissflogii grew faster than of Rhodomonas sp.. The diatom seemed to benefit from better start conditions and would out-compete the cryptophyte during a spring bloom. Our results highlight that these algae groups have different strategies in dealing with darkness, which potentially endow diatoms with a competitive advantage in deep mixed waters and in the season of early spring.     

CRYPTOMONAD EVOLUTION: NUCLEAR 18S rDNA PHYLOGENY VERSUS CELL MORPHOLOGY AND PIGMENTATION1

A nuclear18S rDNA phylogeny for cryptomonad algae is presented, including 11 species yet to be investigated by molecular means. The phylogenetic positions of the cryptomonad genera Campylomonas and Plagioselmis are assessed for the first time. Campylomonas groups most closely with morphologically similar species with the same accessory pigment from the genus Cryptomonas. Plagioselmis groups with the genera Teleaulax and Geminigera forming a clade whose members are united by unusual thylakoid arrangement. Nuclear 18S rDNA phylogeny divides cryptomonads into seven major lineages, two of which consist of the monospecific genera Proteomonas and Falcomonas. Analysis of nuclear18S rDNA sequence supports suggestions that a Falcomonas‐like cryptomonad gave rise to all other blue‐green cryptomonads. New sequence from the plastid‐lacking cryptomonad genus Goniomonas is also included, and the order of divergence of the major cryptomonad lineages is discussed. The morphology, number, and pigmentation of the cryptomonad plastidial complex are congruent with nuclear 18S rDNA phylogenies. Host cell features, such as periplast type, furrow/gullet system, and cell shape, can be more variable and may be markedly different in species that are closely related by nuclear 18S rDNA phylogeny. Conversely, some species that are not closely related by molecular phylogeny may display a very similar, possibly primitive, periplast and furrow morphology.     

Re-examination ofPyrenomonas andRhodomonas (class cryptophyceae) through ultrastructural survey of red pigmented cryptomonads

Several taxa of cryptomonads, including species of marineChroomonas, Cryptomonas and freshwaterRhodomonas were examined using transmission electron microscopy. They have cellular structures fundamentally in common: a single bilobed chlorplast, a single pyrenoid between the chloroplast lobes, and a nuclemorph embedded within a cleft of the pyrenoidal matrix. These features are in accordance with the taxonomic characteristics of the recently established genusPyrenomonas. The algae also have similar pigmentation to that ofRhodomonas andPyrenomonas which is red or reddish-brown. On the basis of these observations, the genusRhodomonas Karsten (1898) is redescribed in this paper and the genusPyrenomonas Santore is considered to be synonymous withRhodomonas.     

Ecological notes on the species of Phacus Dujardin (Euglenophyta) from the central region of Portugal

Twenty-one species, belonging to the genus Phacus, were identified during the study of samples from the central region of Portugal collected in lentic systems. The abundance of each taxon was determined. Water samples were taken for determination, by means of standard methods, of physicochemical parameters (water temperature, pH, organic matter (K₂Cr₂O₇), conductivity, alkalinity, nitrogen as N(NH₄⁺), N(NO₂^–) and N(NO₃^–), orthophosphate P(PO₄^3–) and metals in a total of 35 parameters). Some species were found more frequently, namely Phacus agilis Skuja, Ph. aenigmaticus Drez., Ph. caudatus Hübn., Ph. gigas Da Cunha, Ph. triqueter (Ehr.) Duj., Ph. longicauda (Ehr.) Duj. and Ph. tortus (Lemm.) Skv. Eighteen taxa were found in the sampling sites characterized by the following variation intervals of the environmental parameters: water temperature: 11.4–21.6 °C; pH: 6.2–7.5; dichromate oxidability: 10–59 mg l^–1; conductivity: 145–779 μS cm^–1; nitrogen as NO₃^–: n.d.–2.852 mg l^–1; orthophosphate: n.d.–0.892 mg l^–1; chloride: 14.2–109.3 mg l^–1; sodium: 10.3–47.5 mg l^–1 and total iron: 135–6446 μg l^–1. In this work, information concerning the environmental conditions that preceded the occurrence of these species as well as results of the cytological and morphologic studies (with bright field microscopy as a resource) is presented and discussed.     

Supplementation of the protist Chilomonas paramecium with a highly unsaturated fatty acid enhances its nutritional quality for the rotifer Keratella quadrata

We tested whether a fatty acid supplementation technique usingbovine serum albumin (BSA) as a carrier, previously developedfor autotrophic protists, is also appropriate for supplementationof Chilomonas paramecium—a flagellated heterotrophic protist.Chilomonas paramecium was successfully enriched with eicosapentaenoicacid (EPA) and docosahexaenoic acid (DHA), both known to beessential for crustacean zooplankton. Preparing C. parameciumenriched with EPA and DHA in concentrations similar to thosefound in Cryptomonas phaseolus, an alga known to support highgrowth and reproduction of Keratella, allowed us to test thedirect nutritional effects of EPA and DHA on population growthand reproduction of the rotifer Keratella quadrata. Growth ratesand egg production were highest when K. quadrata was fed withC. phaseolus. Compared to non-supplemented C. paramecium, eggproduction of K. quadrata was significantly enhanced on a dietof C. paramecium enriched with DHA, whereas no significant effectscould be attributed to EPA enrichment. We conclude that DHAis important for reproduction of K. quadrata but cannot explainthe majority of the difference in food quality between C. parameciumand C. phaseolus.     

Gobies of the genus <Emphasis Type="Italic">Rhinogobius</Emphasis> (Gobiidae) from Primor’e and water bodies of Central Asia and Kazakhstan: I. Morphological characteristic and taxonomic status

The taxonomic status of the investigated populations is estimated on the basis of morphological analysis of gobies of the genus Rhinogobius from waters of Primor’e, of gobies introduced with herbivorous fish to water bodies of Central Asia and Kazakhstan, and of morphological traits of the known nominal species of this genus. The gobies from water bodies of Primor’e are attributed to the species R. sowerbyi Ginsburg, 1917 which was supposed to be a junior synonym of R. brunneus. The acclimatized gobies are attributed to R. cheni (Nichols, 1931) described from the Yangtze and not mentioned in literature for a long time. Detailed morphological characteristics of the studied populations, diagnoses, and present-day notions on distribution of both restored species are presented.     

The Neogene Ostracod Genus <Emphasis Type="Italic">Advenocypris</Emphasis> from the Intermontane Depressions of the Southeastern Altai

This paper presents new data on ostracods of the genus Advenocypris. The distribution of these ostracods in the Neogene deposits of the intermontane depressions of Central Asia is analyzed. Species of this genus were selective regarding their habitats. This habitat specificity can be used to reconstruct the paleogeography of the depositional environments, origin and connections of water bodies in Central Asia. A new species of the genus Advenocypris is described. The previously known species of this genus are illustrated.     

Somatic organic content of the ctenophores <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis> (Ctenophora: Lobata) and <Emphasis Type="Italic">Beroe ovata</Emphasis> (Ctenophora: Beroida) in early ontogenetic stages

The organic matter content in the eggs and early larvae of the ctenophores Mnemiopsis leidyi and Beroe ovata from the Black Sea was determined using the adapted microtechnique of dichromate oxidation. The content of organic matter in the eggs of M. leidyi (0.25 μg/indiv.) was 5 times less than in B. ovata (1.28 ± 0.29 μg/indiv.). The somatic content of organic matter was 0.25 ± 0.09 μg/indiv. (25.1 ± 8.3 μg/mg, wet wt) for 2-day-old larvae of M. leidyi (0.2–0.3 mm in body length) and 1.37 ± 0.19 μg/indiv. (67.1 ± 5.7 μg/mg wet wt) for larvae of B. ovata (0.4 mm in body length). The specific organic content of larvae of both species steadily decreased with an increase in ctenophore body size and weight, approaching 3–4 μg/mg of wet weight for 2 mm specimens of M. leidyi and 3–5 μg/mg of wet weight for 6 mm B. ovata. The specific organic content of early larvae was 20–30 times higher than that of adult ctenophores. The results of this investigation could be useful in the evaluation of the energy budget for somatic growth and generative production in these species. Calculations indicate that with specific wet weight growth rates of 0.43/day for M. leidyi larvae and 0.29/day for B. ovata larvae, their true organic increases are respectively 30 and 38% less, i.e., no more than 0.31/day for the former and 0.18/day for the latter species.