bluuebunny/crossref_metadata_2025 huggingface dataset:
MICROENVIRONMENTS AND MICROSCALE PRODUCTIVITY OF CYANOBACTERIAL DESERT CRUSTS1
Authors: Garcia‐Pichel Ferran , Belnap Jayne
Published: October 2004

We used microsensors to characterize physicochemical microenvironments and photosynthesis occurring immediately after water saturation in two desert soil crusts from southeastern Utah, which were formed by the cyanobacteria Microcoleus vaginatus Gomont, Nostoc spp., and Scytonema sp. The light fields within the crusts presented steep vertical gradients in magnitude and spectral composition. Near‐surface light‐trapping zones were formed due to the scattering nature of the sand particles, but strong light attenuation resulted in euphotic zones only ca. 1 mm deep, which were progressively enriched in longer wavelengths with depth. Rates of gross photosynthesis (3.4–9.4 mmol O2·m−2·h−1) and dark respiration (0.81–3.1 mmol O−2·m−2·h−1) occurring within 1 to several mm from the surface were high enough to drive the formation of marked oxygen microenvironments that ranged from oxygen supersaturation to anoxia. The photosynthetic activity also resulted in localized pH values in excess of 10, 2–3 units above the soil pH. Differences in metabolic parameters and community structure between two types of crusts were consistent with a successional pattern, which could be partially explained on the basis of the microenvironments. We discuss the significance of high metabolic rates and the formation of microenvironments for the ecology of desert crusts, as well as the advantages and limitations of microsensor‐based methods for crust investigation.
LECTIN‐LIKE COMPOUNDS AND LECTIN RECEPTORS IN MARINE MICROALGAE: HEMAGGLUTINATION AND REACTIVITY WITH PURIFIED LECTINS1
Authors: Hori Kanji , Ogata Takehiko , Kamiya Hisao , Mimuro Mamoru
Published: October 2004

We detected lectin‐like compounds and lectin receptors in microalgae by hemagglutination, competitive inhibition with sugars, and reactivity with lectins isolated from other sources. Cell extracts from eight species of Dinophyceae and from one species each of Raphidophyceae and Bacillariophyceae exhibited hemagglutination toward trypsinized rabbit erythrocytes. In addition, the culture media of the dinoflagellateAlexandrium cohorticulaand the raphidophyteChattonella antiquadisplayed similar hemagglutination. These activities were not inhibited by any monosaccharides or oligosaccharides tested but were inhibited by some specific glycoproteins. This suggests that the active factors were lectin‐like compounds. Upon exposing intact, healthy cells of 12 species of Dinophyceae and one species each of Raphidophyceae, Cryptophyceae, Bacillariophyceae, and Chlorophyceae to lectins isolated from either macroalgae or terrestrial plants, most species were adversely affected. The negative effects included one or more of the following: impaired motility, disappearance of motility, agglutination, abnormal morphology, and cell rupture or lysis. Some species, even after freezing, thawing, and washing with saline solution, still agglutinated with macroalgal or terrestrial plant lectins. This study suggests that lectins and carbohydrate‐containing lectin receptors may commonly occur on the cell surfaces of various species of microalgae.
MICROENVIRONMENTAL CONTROL OF PHOTOSYNTHESIS AND PHOTOSYNTHESIS‐COUPLED RESPIRATION IN AN EPILITHIC CYANOBACTERIAL BIOFILM1
Authors: Kühl Michael , Glud Ronnie Nøhr , Ploug Helle , Ramsing Niels Birger
Published: October 2004

The photosynthetic performance of an epilithic cyano‐bacterial biofilm was studied in relation to the in situ light field by the use of combined microsensor measurements of O2, photosynthesis, and spectral scalar irradiance. The high density of the dominant filamentous cyanobacteria (Oscillatoria sp.) embedded in a matrix of exopolymers and bacteria resulted in a photic zone of < 0.7 mm. At the biofilm surface, the prevailing irradiance and spectral composition were significantly different from the incident light. Multiple scattering led to an intensity maximum for photic light (400–700 nm) of ca. 120% of incident quantum irradiance at the biofilm surface. At the bottom of the euphotic zone in the biofilm, light was attenuated strongly to < 5–10% of the incident surface irradiance. Strong spectral signals from chlorophyll a (440 and 675 nm) and phycobilins (phycoerythrin 540–570 nm, phycocyanin 615–625 nm) were observed as distinct maxima in the scalar irradiance attenuation spectra in the upper 0.0–0.5 mm of the biofilm. The action spectrum for photosynthesis in the cyanobacterial layer revealed peak photosynthetic activity at absorption wavelengths of phycobilins, whereas only low photosynthesis rates were induced by light absorption of carotenoids (450–550 nm).

Respiration rates in light‐ and dark‐incubated biofilms were determined using simple flux calculations on measured O2 concentration profiles and photosynthetic rates. A significantly higher areal O2 consumption was found in illuminated biofilms than in dark‐incubated biofilms. Although photorespiration accounted for part of the increase, the enhanced areal O2 consumption of illuminated biofilms could also be ascribed to a deeper oxygen penetration in light as well as an enhanced volumetric O2 respiration in and below the photic zone. Gross photosynthesis was largely unaffected by increasing flow velocities, whereas the O2 flux out of the photic zone, that is, net photosynthesis, increased with flow velocity. Consequently, the amount of produced O2 consumed within the biofilm decreased with increasing flow velocity. Our data indicated a close coupling of photosynthesis and respiration in biofilms, where the dissolved inorganic carbon requirement of the photo‐synthetic population may largely be covered by the respiration of closely associated populations of heterotrophic bacteria consuming a significant part of the photosynthetically produced oxygen and organic carbon.
PHYSIOLOGICAL RESPONSES TO PHOSPHORUS LIMITATION IN BATCH AND STEADY‐STATE CULTURES OF DUNALIELLA TERTIOLECTA (CHLOROPHYTA): A UNIQUE STRESS PROTEIN AS AN INDICATOR OF PHOSPHATE DEFICIENCY1
Authors: Graziano Lisa M. , La Roche Julie , Geider Richard J.
Published: October 2004

A protein unique to phosphorus stress observed in Dunaliella tertiolecta Butcher was studied in the context of phosphate‐limited cell physiology and is a potential diagnostic indicator of phosphate deficiency in this alga. Cells were grown over a range of limited, steady‐state growth rates and at maximum (replete) and zero (phosphate‐starved) growth rates. The stress protein, absent in nutrient‐replete cells, was produced under all steady‐state phosphate‐limited conditions and increased in abundance with increasing limitation (decreasing growth rate). Cellular carbon: phosphorus ratios and the maximum uptake rate of phosphate (Vm) increased with increasing limitation, whereas the ratio of chlorophyll a: carbon decreased. Alkaline phosphatase activity did not respond to limitation but was measurable in starved, stationary‐phase cells. Fv/Fm, a measure of photochemical efficiency, was a nonlinear, saturating function of p, as commonly observed under N limitation. The maximum Fv/Fm of 0.64 was measured in nutrient‐replete cells growing at μmax, and a value of zero was measured in stationary‐phase starved cells. When physiological parameters were compared, the P‐stress protein abundance and Fv/Fm were the most sensitive indicators of the level of deficiency. The stress protein was not produced under N‐ or Fe‐limited conditions. It is of high molecular weight (>200) and is associated with internal cell membranes. The stress protein has several characteristics that make it a potential diagnostic indicator: it is 1) unique to phosphorus limitation (i.e. absent under all other conditions), 2) present under limiting as well as starved conditions, 3) sensitive to the level of limitation, and 4) observable without time‐course incubation of live samples.
EFFECT OF MALTOSE RELEASE ON UPTAKE AND ASSIMILATION OF AMMONIUM BY SYMBIOTIC CHLORELLA (CHLOROPHYTA)1
Authors: McAuley Paul J. , Dorling Matthew , Hodge Harry
Published: October 2004

When incubated at pH 4–5, Chlorella freshly isolated from symbiosis with Hydra viridissima PALLAS 1766 (green hydra) release large amounts of photosynthetically fixed carbon in the form of maltose, and assimilation of inorganic N is inhibited. Physiological responses to N starvation of the cultured 3N813A strain of maltose‐releasing Chlorella differed from those caused by 48 h of maltose release induced by low pH. N starvation increased rates of ammonium assimilation at pH 7.0 in light or darkness, and ammonium assimilation in darkness stimulated cell respiration. In contrast, cells pretreated at pH 5.0 to induce maltose release were unable to take up ammonium at pH 7.0 unless supplied with an external carbon source such as bicarbonate, acetate, or succinate, and rates of uptake were similar to control cells. Freshly isolated symbionts displayed a similar dependency. Rates of ammonium uptake by cells pretreated at pH 5.0 were reduced in darkness and did not stimulate cell respiration. N‐starved cells supplied with ammonium also showed a large short‐term increase in glutamine pools at the expense of glutamate, as might be expected if large amounts of ammonium were rapidly assimilated via glutamine synthetase/glutamate synthase, whereas after long‐term maltose release cells showed only a small increase in glutamine when supplied with ammonium. Furthermore, maltose release caused a fall in pool sizes of a number of amino acids, including glutamine and glutamate, and also caused a decrease in pool sizes of 2‐oxoglutarate and phospho‐enol‐pyruvate, which are required for ammonium assimilation into amino acids.

Cells stimulated to synthesize and release maltose may be unable to assimilate ammonium and synthesize amino acids because of diversion of fixed carbon from N metabolism. We estimate that 40–50% affixed C is required for maximal maltose synthesis, whereas up to 30% fixed C is required for ammonium assimilation. These results are discussed in the context of host regulation of symbiotic algal growth.
DISTINCTIVE LECTIN LABELING OF THE FLAGELLAR APPARATUS OF TETRASELMIS (PRASINOPHYCEAE) AND DUNALIELLA (CHLOROPHYCEAE)1
Authors: Costas Eduardo , Hevia Elena , Carretero Yolanda , López‐Rodas Victoria
Published: October 2004

Fluorescent labeling of the flagellar apparatus of Tetraselmis (Prasinophyceae) and Dunaliella (Polyblepharidaceae, Chlorophyceae) were successfully performed using fluorescein isothiocyanate–labeled lectins from Arachis hypogaea and Glycine maxima. These lectins specifically bound to the flagella and kinetosome of the cell but did not bind to the cell surface. Lectin binding on the flagellar apparatus remained constant under different culture media, temperatures, irradiances, cell division cycle, and culture aging. All the Tetraselmis and Dunaliella analyzed (five species, 20 clones) showed intense labeling of the flagellar apparatus. In contrast, no other species analyzed (46 clones of 25 species from four classes) showed binding to their flagellar apparatus. After the lectin treatment, many cells remained alive, and they were able to swim with the flagellar apparatus intensely labeled. The lectin binding indicates that the flagella and kinetosome of Tetraselmis are rich in Gal and GalNH2 moieties and that the flagella of Dunaliella are rich in Gal and GalNAc moieties. Apparently, this feature seems to be specific to these species.
IDENTIFICATION OF THE CLASS PRYMNESIOPHYCEAE AND THE GENUSPHAEOCYSTISWITH RIBOSOMAL RNA–TARGETED NUCLEIC ACID PROBES DETECTED BY FLOW CYTOMETRY1
Authors: Lange Martin , Guillou Laure , Vaulot Daniel , Simon Nathalie , Amann Rudolf I. , Ludwig Wolfgang , Medlin Linda K.
Published: October 2004

Target regions specific for the class Prymnesiophyceae and the genusPhaeocystis(Har.) Lag. were identified from 18S ribosomal RNA coding regions, and two complementary probes were designed (PRYMN01 and PHAEO01). Detection of whole cells hybridized with these probes labeled with fluorescein isothiocyanate was difficult using epifluorescence microscopy because autofluorescence of the chlorophylls seriously interfered with the fluorescence of the probes. In contrast, flow cytometry proved very useful to detect and quantify the fluorescence of the hybridized cells. Hybridization conditions were optimized, especially with respect to formamide concentration. Both probes were tested on a large array of both target and nontarget strains. Positive and negative controls were also analyzed. Specificity was tested by adding a competing nonlabeled probe. Whereas probe PHAEO01 seems to have good specificity, probe PRYMN01 appeared less specific and must be used with stringent positive and negative controls.
ANALYSIS OF THE EXPRESSION OF GENES FOR P‐TYPE ATPASE IN THE HALOTOLERANT ALGA DUNALIELLA SALINA (CHLOROPHYCEAE)1
Authors: Wada Masato , Hirokawa Aki , Fukumoto Ryou‐hei , Shono Mariko
Published: October 2004

A partial complementary DNA (cDNA) (DSA8) for a P‐type ATPase was obtained from the halotolerant alga Dunaliella salina (Dunal) Teod. (Chlorophyceae). The cDNA exhibited greater than 90% homology to the cDNA for a H+‐ATPase in D. bioculata Butcher. The expression of the gene that corresponded to DSA8 was decreased strongly by increases in NaCl concentration. The expression of a gene that corresponded to another ATPase (DSA1; possibly for a Ca2+‐ATPase) from D. salina did not show the same decrease as did the DSA8. However, increased osmotic pressure due to glycerol resulted in the same decrease in the DSA8 gene. Under salt or osmotic stress, the activity of a H+‐ATPase from microsomes of this alga also decreased. We suggest that expression of the gene for the plasma membrane H+‐ATPase of D. salina is regulated by osmotic pressure rather than by the concentration of NaCl.
A SPECTROPHOTOMETRIC ASSAY FOR RUBISCO ACTIVITY: APPLICATION TO THE KELP LAMINARIA SACCHARINA AND IMPLICATIONS FOR RADIOMETRIC ASSAYS1
Authors: Gerard Valrie A. , Driscoll Timothy
Published: October 2004

We optimized a spectrophotometric method for measuring ribulose‐l,5‐bisphosphate carboxylase oxygenase (Rubisco) activity in crude extracts of the kelp Laminaria saccharina Lamour. Activity exhibited a decline during the assays, such that rates determined over a 10‐min period were only 70% of activity during the first minute. Activity was significantly enhanced by addition of HCO3− to the extraction buffer and was stable for at least 4 h. Highest activities were determined using small extract loads (1–2.5 mg fresh weight·mL−1 of assay mixture); extract loads of 10 mg·mL−1caused a 25% decrease in activity. Rubisco activities determined for individual kelp plants using the spectrophotometric method were significantly correlated with total protein and gross photo synthetic capacity (Pmax) and were 1.5–2 times higher than Pmax. Low Rubisco activities relative to photosynthetic rates reported in many previous studies of macroalgae and microalgae may have resulted at least partly from underestimation of enzyme activity by radiometric assays using relatively large volumes of un‐activated crude extract and assay periods longer than 1 min.
GROWTH AND NITROGEN FIXATION OF THE DIAZOTROPHIC FILAMENTOUS NONHETEROCYSTOUS CYANOBACTERIUM TRICHODESMIUM SP. IMS 101 IN DEFINED MEDIA: EVIDENCE FOR A CIRCADIAN RHYTHM1
Authors: Chen Yi‐Bu , Zehr Jonathan P. , Mellon Mark
Published: October 2004

Trichodesmium sp. IMS 101, originally isolated from coastal western Atlantic waters by Prufert‐Bebout and colleagues and maintained in seawater‐based media, was successfully cultivated in two artificial media. Its characteristics of growth, nitrogen fixation, and regulation of nitrogen fixation were compared to those of natural populations and Trichodesmium sp. NIBB 1067. Results indicate that the culture grown in artificial media had nitrogen fixation characteristics similar to those when the culture is grown in seawater‐based medium and to those of Trichodesmium sp. in the natural habitat. The study provides practical artificial media to facilitate the physiological studies of these important diazotrophic cyanobacteria, as well as the cultivation of other Trichodesmium species in future studies. Manipulations of the light/dark cycle were performed to determine whether or not the daily cycle of nitrogen fixation is a circadian rhythm. Cultures grown under continuous light maintained the cycle for up to 6 days. We demonstrated that the daily cycle of nitrogen fixation in Trichodesmium sp. IMS 101 was at least partially under the control of a circardian rhythm.
CORRELATED BIOCHEMICAL AND ULTRASTRUCTURAL CHANGES IN NITROGEN‐STARVED EUGLENA GRACILIS1
Authors: García‐Ferris Carlos , de los Ríos Asunción , Ascaso Carmen , Moreno Joaquín
Published: October 2004

Growth of Euglena gracilis Z Pringsheim under photoheterotrophic conditions in a nitrogen‐deprived medium resulted in progressive loss of chloroplastic material until total bleaching of the cells occurred. Biochemical analysis and ultrastructural observation of the first stages of the starvation process demonstrated an early lag phase (from 0 to 9 h) in which cells increased in size, followed by a period of cell division, apparently supported by the mobilization of some chloroplastic proteins such as the photosynthetic CO2‐fixing enzyme ribulose‐1,5‐bisphosphate carboxylase/oxygenase. The degradation of the enzyme started after 9 h of starvation and was preceded by a transient concentration of this protein in pyrenoidal structures. Protein nitrogen and photosynthetic pigments as well as number of chloroplasts per cell decreased during proliferation through mere distribution among daughter cells. However, after 24 h, when cell division had almost ceased, there was a slow but steady decline of photosynthetic pigments. This was paralleled by observable ultrastructural changes including progressive loss of chloroplast structure and accumulation of paramylon granules and lipid globules in the cytoplasm. These findings reinforce the role of chloroplastic materials as a nitrogen source during starvation of E. gracilis in a carbon‐rich medium. The excess of ribulose‐1,5‐bisphosphate carboxylase/oxygenase acts as a first reservoir that, once exhausted, is superseded by the generalized disassembly of the photosynthetic structures, if the adverse environment persists more than 24 h.
A SPOROPHYTE CELL WALL PROTEIN OF THE RED ALGA PORPHYRA PURPUREA (RHODOPHYTA) IS A NOVEL MEMBER OF THE CHYMOTRYPSIN FAMILY OF SERINE PROTEASES1
Authors: Liu Qing Yan , Reith Michael
Published: October 2004

A complementary DNA (cDNA) clone from a Porphyra purpurea (Roth) C. Agardh sporophyte‐specific subtracted cDNA library was found to encode a protein similar to serine proteases of the chymotrypsin class. The encoded protein contains a typical signal peptide and is particularly similar to chymotrypsins in the regions surrounding the active site residues and the activation site where cleavage of the propeptide occurs. In addition, the six cysteine residues characteristic of chymotrypsins are conserved. However, two of the three residues of the active site His/Asp/Ser charge relay triad have been replaced, indicating that the protein is unlikely to have peptidase activity. Northern hybridization confirmed that this cDNA is derived from an abundant, sporophyte‐specific messenger RNA (mRNA). The presence of signal peptide on the encoded protein and the abundance of its mRNA suggested that this protein might be localized in the cell wall. Consequently, sporophyte cell walls were isolated and a major protein having a molecular weight similar to that estimated for the encoded protein was purified. N‐terminal sequence analysis indicated that this cell wall protein is identical to that encoded by the cDNA with the amino terminus of the mature protein beginning at the activation site. This cell wall structural protein appears to have evolved from a chymotrypsin‐like progenitor but has been adapted to bind cell wall proteins and/or polysaccharides rather than to cleave proteins.
DIFFERENTIATION OF ULVA MUTABILIS (CHLOROPHYTA) GAMETANGIA AND GAMETE RELEASE ARE CONTROLLED BY EXTRACELLULAR INHIBITORS1
Authors: Stratmann Johannes , Paputsoglu Georg , Oertel Wolfgang
Published: October 2004

Blade cells of Ulva mutabilis Føyn (Chlorophyta) excrete regulatory factors into their cell walls and into the environment. These factors are essential for the maintenance of the vegetative state. “Sporulation inhibitor‐1a” (SI‐1a) is a glycoprotein that was isolated from the culture medium of axenic Ulva growing as an undifferentiated callus. This protein was unusually stable to denaturing treatments and showed an extremely high apparent molecular mass (Mr) of 1–4 × 107 daltons estimated by size exclusion chromatography. The glycosylation was not essential for activity. SI‐1a suppressed gametogenesis completely at concentrations lower than 10−14 M. When Ulva developed normally in the presence of their symbiotic bacteria, smaller forms of SI‐1 accumulated in the medium (104–106 daltons). Sporulation inhibitors of the same size spectrum and with similar properties were also extracted from crude cell walls of nonaxenic Ulva. A class of different nonprotein sporulation inhibitors (SI‐2) of very low Mr and yet unknown structure was isolated from the inner space between the two blade cell layers. Excretion of all SI‐1 forms decreased with maturation of the thallus, whereas the overall concentration of SI‐2 in the thallus stayed constant throughout the life cycle. The SI‐2 affected different Ulva species whereas SI‐1 was species‐specific. Gametogenesis was induced upon removal of both Sporulation inhibitors from small single‐layered fragments of mature blades.

After a “determination phase” of 23–46 h, dependent on the time of induction within the cell cycle, the cells became irreversibly committed to differentiation and were no longer susceptible to SI‐1 or SI‐2. Subsequently, during a 28‐h “differentiation phase,” 16 progametes were formed by synchronous genome doublings and cell divisions and differentiated into mature gametes. These became motile and were released from the gametangia when the concentration of a “swarming inhibitor” of low Mr, excreted mainly during the “determination phase,” declined below a threshold concentration. The biochemical properties of these regulatory factors and their effects on gametogenesis and gamete release are described.
DNA SEQUENCE VARIATION IN THE RIBOSOMAL INTERNAL TRANSCRIBED SPACER REGION OF FRESHWATER CLADOPHORA SPECIES (CHLOROPHYTA)1
Authors: Marks Jane C. , Cummings Michael P.
Published: October 2004

Freshwater species of Cladophora (Chlorophyta) are globally distributed and occupy an unusually wide range of ecological habitats. Delineating species is difficult because most easily observed morphological traits are highly variable and because sexual reproduction has not been clearly documented. Synthesizing ecological data on freshwater Cladophora species is problematic because it is unclear whether freshwater Cladophora species comprise many genetically distinct species or a few ecologically and morphologically variable and/or plastic species. We determined nucleotide sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal cistron of freshwater Cladophora species from a wide range of habitats and geographic locations. We compared these sequences to those derived from culture collections of C. fracta and C. glomerata, the two most commonly reported freshwater Cladophora species. Cladophora fracta and C. glomerata had very similar ITS sequences (95.3%). All other sequences were identical to those from the C. fracta or C. glomerata culture collections with the exception of one California sample that was similar to both C. fracta (95.6%) and C. glomerata (92.4%). ITS genotypes did not correlate with morphology or geography. This analysis shows that common freshwater Cladophora species comprise very few (possibly one) ecologically and morphologically variable species.
RANDOM AMPLIFIED POLYMORPHIC DNA MARKERS (RAPDs) AS TOOLS FOR GENE MAPPING IN CHLAMYDOMONAS EUGAMETOS (CHLOROPHYTA)1
Authors: Haring Michel A. , Schuring Frank , Urbanus Jos , Musgrave Alan , van den Ende Herman , Ferris Patrick J.
Published: October 2004

Studying the sexual behavior of the heterothallic green alga Chlamydomonas eugametos Moewus has revealed genetic differences among the few available strains: different O‐methylated sugar patterns on plasma membrane glycoproteins (oms A/B locus) and light‐(in)dependent sexual agglutinin activation (lsa locus). However, due to the lack of a reliable linkage map, genes controlling these traits are not accessible by map‐based cloning. Here we present a partial linkage map for Chlamydomonas eugametos based on random amplified polymorphic DNA (RAPD) markers and one restriction fragment‐length polymorphism (RFLP) marker. Most of these RAPDs (80%) represent unique DNA sequences, which implies that they can be used as starting points for chromosome walking. RAPDs linked to the lsa locus, the mating type locus (mt), and the oms A/B locus were identified by bulk segregant analysis.
IDENTIFICATION OF THE TOXIC DINOFLAGELLATES ALEXANDRIUM CATENELLA AND A. TAMARENSE (DINOPHYCEAE) USING DNA PROBES AND WHOLE‐CELL HYBRIDIZATION1
Authors: Adachi Masao , Sako Yoshihiko , Ishida Yuzaburo
Published: October 2004

Fluorescent DNA probes (cCAT‐F1 and cTAM‐Fl) complementary to the 3′ end of ribosomal RNA (rRNA) internal transcribed spacer 1 sequences (ITS 1: positions 154–176) of toxic species of Alexandrium catenella (Whedon and Kofoid) Taylor and A. tamarense (Lebour) Taylor were applied to various cultures of the genus Alexandrium and several other phytoplankters using whole‐cell fluorescent in situ hybridization. cCAT‐F1 and cTAM‐F1 reacted with targeted strains of A. catenella (catenella type) and A. tamarense (tamarense type), respectively, and did not react with isolates of A. affine (Inoue et Fukuyo) Balech, A. fraterculus (Balech) Balech, A. insuetum Balech, A. lusitanicum Balech, A. pseudogonyaulux (Biecheler)Horiguchi ex Yuki et Fukuyo comb. nov., nor isolates of Prorocentrum micans Ehrenberg, Amphidinium carterae Hulburt, Heterocapsa triquetra (Ehrenberg) Stein, Gymnodinium mikimotoi Miyake et Kominami ex Oda, Skeletonema costatum (Greville) Cleve, Heterosigma akashiwo (Hada) Hada, and Chattonella antiqua (Hada) Ono. DNase I and RNase A treatment showed that probes hybridized to ribosomal DNA, not rRNA. Probes were localized at the bottom of the U‐shaped nucleus, a region that corresponds to the nucleolus. The probes are highly specific for particular strains of A. catenella and A. tamarense and are applicable for identifying these species collected from cultured and possibly natural populations.
FURTHER SEM STUDY OF MARINE DINOFLAGELLATES: THE GENUSOSTREOPSIS(DINOPHYCEAE)1
Authors: Faust Maria A. , Morton Steve L. , Quod Jean P.
Published: October 2004

This paper presents a comprehensive examination of the taxonomy of the genusOstreopsisSchmidt. The morphology of six species of marine dinoflagellates,Ostreopsis siamensisSchmidt 1902.Ostreopsis lenticularisFukuyo 1981,Ostreopsis ovataFukuyo 1981,Ostreopsis heptagonaNorris, Bomber, et Balech 1985,Ostreopsis mascarenensisQuod 1994, andOstreopsis labensFaust et Morton 1995 from three geographical regions (Japan, Southwest Indian Ocean, and the Caribbean) and three marine habitats (sand, water column, and macroalgal surfaces) are described from scanning electron micrographs. Differences in the following morphological characteristics differentiated the species: cell shape and size, and ornamentation of the epitheca, cingulum, and hypotheca. The thecal plate formula of the sixOstreopsisspecies is Po,3′, 7″, 6C, 6S?, Vp, Rp, 5′″, 1p, 2″″, with differences in thecal plate size and shape. The cingulum in ventral view has two prominent structures: a ventral plate (Vp) with a ventral pore (Vo) and a ridged plate (Rp) that distinguishesOstreopsisspecies from any other dinoflagellate taxa. This paper also includes ecological and toxicity information regarding the sixOstreopsisspecies.
DETERMINATION OF RNA AND DNA CONCENTRATIONS IN NATURAL PLANKTON SAMPLES USING THIAZOLE ORANGE IN COMBINATION WITH DNASE AND RNASE DIGESTIONS1
Authors: Fara Angela , Berdalet Elisa , Arin Laura
Published: October 2004

A fluorometric technique, based on the combination of RNase and DNase incubation with the use of thiazole orange (RNase/DNase method), was investigated to determine DNA and RNA concentrations in marine plankton. Tests were performed to optimize both RNase and DNase assay conditions. The RNase assay should be conducted at 37° C for 20 min with 0.5 μg·mL−1 of DNase‐free RNase. An incubation at 25° C for 20 min with 10 units ·mL‐1 of RNase‐free DNase were the optimal conditions required for DNA digestion by DNase. The detection limits in terms of minimum biomass for reliable measurements of DNA and RNA were 7.5 and 10 μg of protein · (mL assay)−1, respectively.

RNA and DNA concentration were estimated in oligotrophic water samples using the RNase/DNase and other available methods (e.g. a double fluorochrome method). The different techniques provided similar DNA estimations. However, the RNase/DNase method provided the highest sensitivity and a low variability for the estimation of RNA.
AN EMPIRICAL PROTOCOL FOR WHOLE‐CELL IMMUNOFLUORESCENCE OF MARINE PHYTOPLANKTON1
Authors: Lin Senjie , Carpenter Edward J.
Published: October 2004

An immunofluorescence protocol for intracellular antigens of phytoplankton was developed empirically. Paraformaldehyde (4%) was used to fix samples for 6 h at 4° C; fixed samples can be stored in cold (–20°C) methanol for at least 1 month. We used Triton X‐100, Nonidet P‐40, and dimethyl sulfoxide to permeabilize the cells for antibody penetration across the cell wall and plasma membrane. After immunolabeling at room temperature, the samples were mounted on slides and could be stored at 4° C for up to 6 months without significant decay of the fluorescence. The staining was examined with an epifluorescence microscope; semiquantitative (percentage of cells with positive staining) and quantitative (staining intensity measured with an imaging system) analyses were performed. Reproducible staining was achieved for nuclear, chloroplastic, cytoplasmic, and cell surface antigens in species of Chlorophyceae, Prymnesiophyceae, Bacillariophyceae, and Dinophyceae including some field‐collected samples. This protocol is advantageous to previously published protocols in that it allows relatively simple and long‐term storage of fixed samples and allows staining of multiple antigens for the same sample. Although improvement on cell permeabilization is required for some species, the present protocol could prove useful for physiological or ecological studies when frequent sampling is required and immediate processing of the samples is not possible.
Close Physical Contact of the Heart with Diaphragm Causes Pseudo‐Asynergy of Left Ventricular Inferior Wall in Normal Subjects
Authors: Sakurai Susumu , Takenaka Katsu , Shiojima Ichiro , Sonoda Makoto , Uno Kansei , Nakahara Kazuhiko , Nagai Ryozo
Published: October 2004

Paradoxical outward movement of left ventricular (LV) inferior wall in systole is occasionally recognized in normal subjects and clinically important in terms of the differential diagnosis between physiological pseudo‐asynergy and pathological asynergy. In this study, the potential mechanisms by which pseudo‐asynergy of LV inferior wall (PLI) is observed in normal subjects were investigated. PLI was defined as the outward movement of LV inferior wall observed during more than 50% of systole. The incidence of PLI was evaluated in 7843 consecutive subjects in routine echocardiography. The effects of body position and artificial gravity on the manifestation of PLI were also examined. PLI was observed in 0.11% (9/7842) of subjects on left lateral position. Measurement of the angle formed by LV long‐axis and the long‐axis of the body on frontal plane revealed that hearts in subjects with PLI were in relatively horizontal position. PLI was observed on sitting position in 43% (40/92) of subjects without PLI on left lateral position. The subjects with sitting position‐induced PLI exhibited significantly higher obesity index. PLI was also induced by artificial gravity in 67% (14/21) of healthy volunteers on supine position, and the degree of PLI correlated with the intensity of gravity. Although the incidence of PLI in routine echocardiography is relatively low, PLI can be induced in normal subjects by any condition that causes close contact of LV inferior wall to diaphragm. Thus, PLI should be taken into consideration in the differential diagnosis of abnormal LV inferior wall motion, especially when performing exercise echocardiography.
High Prevalence of Isovolumic Relaxation Flow in Healthy Subjects
Authors: Voon Wen‐Chol , Huang Chih‐Hsin , Lin Tsung‐Hsien , Lai Wen‐Ter , Sheu Sheng‐Hsiung
Published: October 2004

Background: Inhomogenous left ventricular activation–inactivation has been suggested to play a role in the genesis of segmental early relaxation and in turn of isovolumic relaxation flow (IRF). The spatial distribution of conduction system in the left ventricle leads to heterogenous activation sequence even in healthy subjects. This study was conducted to evaluate our hypothesis that IRF should be ubiquitous in healthy subjects. Methods: This prospective study included 126 healthy subjects (aged 15–81 years) free of acute or chronic illness by history and physical examination. No significant abnormality appeared in the resting 12‐lead electrocardiogram or transthoracic echocardiogram. With the pulsed‐wave Doppler echocardiography, the sample volume was placed at the mid‐ventricle to detect the IRF. Results: An apically directed IRF, with the velocity 17–101 cm/sec and the duration 57–145 ms, could be detected in all the study subjects. There was no inter‐sex difference in such characteristics of IRF. However, its duration and velocity got longer and higher with aging. The fractional shortening of the left ventricle and the interventricular septal thickness were stepwisely selected as the determinants of the IRF velocity, and the transmitral E‐to‐A wave velocity ratio, the left ventricular inflow propagation velocity, and the interventricular septal thickness as the determinants of the IRF duration. Conclusions: IRF is ubiquitous in healthy subjects. Both the duration and the velocity of IRF present an aging trend and may be mainly related to left ventricular diastolic and systolic performance, respectively.
Aneurysm of Sinus of Valsalva Dissecting into Interventricular Septum: A Late Complication of Aortic Valve Replacement
Authors: Güler Niyazi , Eryonucu Beyhan , Tuncer Mustafa , Aşker Müntecep
Published: October 2004

A 43‐year‐old man who had a Carbomedics prosthetic aortic valve replacement in 1997 was admitted to our hospital with complaints of shortness of breath and dyspnea on exertion in 2000. The patient was hospitalized due to atrioventricular (AV) complete block and a permanent pacemaker was implanted. At that time echocardiography indicated an aneurysm at the left sinus of Valsalva. In 2003, the patient was re‐admitted to our clinic with complaints of shortness of breath and fatigue. Echocardiography showed a sinus of Valsalva aneurysm dissecting into interventricular septum. Operation confirmed dissection of the interventricular septum and communication between this cavity and the aneurysm of the left sinus of Valsalva. The postoperative course was uneventful and the patient was discharged in a satisfactory condition. This is the first reported case of aneurysm of the sinus of Valsalva dissecting into interventricular septum late and complicating aortic valve replacement.
Left Atrial Mass: Thrombus Mimicking Myxoma
Authors: Dhawan Sumeesh , Tak Tahir
Published: October 2004

A 31‐year‐old woman underwent elective transthoracic echocardiography for paroxysmal atrial fibrillation, which showed a large left atrial mass. A two‐dimensional echocardiogram showed a large left atrium mass. Subsequent transesophageal echocardiography showed a 3 cm × 3 cm circular mass with smooth contours. The differential diagnosis included myxoma versus thrombus, but because of morphology and mobility of the mass, it was difficult to differentiate one from the other. The patient had been on chronic coumadin therapy for paroxysmal atrial fibrillation. An operation was performed and the intracardiac mass resected. On pathologic examination the mass was diagnosed as an organized thrombus. A brief review of the literature has been presented to discuss the differential diagnosis of the mass in the left atrium.
A Rare Cause of Reversible Dilated Cardiomyopathy: Hypocalcemia
Authors: Avsar Alaettin , Dogan Abdullah , Tavli Talat
Published: October 2004

Hypocalcemia is a rare cause of reversible heart failure. We reported a 40‐year‐old woman who had severe heart failure resistant to the usual antifailure therapy. She had severe hypocalcemia due to hypoparathyroidism after strumectomy. Echocardiography showed a large left ventricle with very low ejection fraction of 25% and moderate mitral regurgitation. After supplementation of calcium and vitamin D, her clinical situation and hemodynamics improved rapidly. At 15 months, myocardial impairment resolved fully. In conclusion, hypocalcemia should be considered in the differential diagnosis of resistant severe heart failure.
Right Atrial Aneurysm in Adults—Report of Three Cases and Review of Literature
Authors: Chockalingam Anand , Alagesan R. , Gnanavelu G. , Dorairajan Smrita , Subramaniam T.
Published: October 2004

Right atrial aneurysm (RAA) or RA diverticula are described as saccular structures originating from the RA free wall. This must be differentiated from aneurysmal dilation of the entire right atrium. We diagnosed three cases of RAA since 2000. The first patient presented with effort intolerance, the second with recurrent palpitations, and the third was totally asymptomatic. In all the cases transthoracic echocardiography was definitive with little additional information obtained from catheterization. We report our experience and review the literature pertaining to adult presentation of this interesting pathology, of which only 20 cases have thus far been reported.
Maximal Longitudinal Contraction Velocity in Assessment of Left Ventricular Systolic Function: A Pulsed Tissue Doppler and M‐Mode Study
Authors: Wandt Birger , Fornander Ylva , Egerlid Rigmor
Published: October 2004

Aims: During recent years the maximal longitudinal contraction velocity (MLCV), measured by either pulsed tissue Doppler or M‐mode, has been suggested as an index of left ventricular (LV) systolic function. The aims of the present study were to compare MLCV with ejection fraction (EF) in consecutive patients with known or suspected heart failure and to compare measures from recordings by pulsed tissue Doppler with recordings by M‐mode. Methods and Results: Sixty‐four consecutive patients with suspected or known heart failure, referred to echocardiography, were included. Twelve of these patients had decreased LV systolic function defined as EF < 50% calculated by the biplane Simpson´s rule, while a significantly (P > 0.05) higher proportion of 23 had decreased function defined as decreased MLCV recorded by pulsed tissue Doppler. Measures from M‐mode recordings were significantly lower (P < 0.001) than the corresponding measures from tissue Doppler recordings. Conclusions: The study shows that higher values of MLCV are obtained by pulsed tissue Doppler than by M‐mode. Reference values can therefore not be used interchangeably. The results also suggest that MLCV is a more sensitive index of LV systolic function than EF.
Survival to the Age of 52 Years in a Man with Unrepaired Tetralogy of Fallot
Authors: Makaryus Amgad N. , Aronov Iosif , Diamond Joseph , Park Chong H. , Rosen Stacey E. , Stephen Bibiana
Published: October 2004

Tetralogy of Fallot is the most common cyanotic congenital heart defect during infancy. It is composed of a ventricular septal defect, an overriding aorta, obstruction of right ventricular outflow, and right ventricular hypertrophy. Most patients experience cyanosis at birth and die in childhood without surgical intervention. The rate of survival at 40 years without surgical correction is only 3%. We present the case of a man with tetralogy of Fallot who survived until the age of 52 years without surgical intervention.
New insights into the proton‐dependent oxygen affinity of Root effect haemoglobins
Authors: Bonaventura C. , Crumbliss A. L. , Weber R. E.
Published: October 2004

A long‐standing puzzle with regard to protein structure/function relationships is the proton‐dependent modification of haemoglobin (Hb) structure that causes oxygen to be unloaded from Root effect Hbs into the swim bladders and eyes of fish even against high oxygen pressure gradients. Although oxygen unloading in Root effect Hbs has generally been attributed to proton‐dependent stabilization of the T‐state, protonation of Root effect Hbs can alter their ligand affinities in both R‐ and T‐state conformations and either stabilize the T‐state or destabilize the R‐state. The C‐terminal residues that are so important in the Bohr effect of human Hb appear to be involved in the Root effects of some fish Hbs and not in others, indicating that several evolutionary pathways have resulted in expression of highly pH‐dependent Hbs. New data are presented that show surprising similarities in the pH‐ and anion‐dependence of sulfhydryl group reactivity and anaerobic oxidation of human and fish Hbs. The available evidence supports the concept that in both Bohr effect and Root effect Hbs a large steric component acts in addition to quaternary shifts between R and T conformations to regulate ligand affinity. Allosteric effectors moderate these steric effects within both R‐ and T‐state conformations and allow for an elegant match between Hb function and the wide‐ranging physiological needs of diverse organisms.
Effect of exogenous angiotensin II on renal tissue nitric oxide and intrarenal circulation in anaesthetized rats
Authors: Bądzyńska B. , Grzelec‐Mojzesowicz M. , Sadowski J.
Published: October 2004

Aim:  The renal medullary circulation is protected against depressor action of angiotensin II (Ang II) because of the opposed action of a vasodilator agent, possibly nitric oxide (NO). This possibility was evaluated by a simultaneous determination of the effect of exogenous Ang II on renal cortical and medullary tissue NO and on intrarenal circulation.

Methods:  In anaesthetized rats effects were determined of pressor and subpressor Ang II doses on tissue NO concentration in the renal cortex and inner medulla (selective NO electrodes), total renal blood flow (RBF, Transonic renal artery probe) and inner medullary blood flow (IMBF, laser Doppler flux). The measurements were repeated in rats treated with tempol, a scavenger of superoxide.

Results:  Moderately pressor Ang II infusion significantly decreased tissue NO signal from 5.7 ± 0.2 to 5.3 ± 0.2 nA in the cortex and from 10.7 ± 0.6 to 10.1 ± 0.6 nA in the medulla. The RBF, a measure of cortical perfusion, decreased, and IMBF did not change. Subpressor doses of Ang II did not change medullary or cortical tissue NO. Tempol prevented an Ang II dependent decrease in medullary (but not cortical) NO without affecting RBF or IMBF responses.

Conclusion:  An absence of an increase in renal cortical or medullary tissue NO after infusion of subpressor or pressor doses of Ang II speaks against the role of this agent in buffering the intrarenal vasoconstrictor action of the hormone. Elimination of the post‐Ang II decrease in medullary NO in animals pre‐treated with tempol suggests that tissue superoxide generation stimulated by the hormone might reduce local bioavailability of NO.
Review article: the pharmacodynamics and pharmacokinetics of proton pump inhibitors – overview and clinical implications
Authors: Robinson M.
Published: October 2004

During the past two decades, enormous changes occurred in the management of gastric acid‐related diseases. First, the histamine2‐receptor antagonists were introduced, offering patients the first single‐agent therapy that effectively reduced gastric acid secretion. Proton pump inhibitors became widely available in the early 1990s, and they generally appeared to be superior to the histamine2‐receptor antagonists in acid‐suppressing activity, symptom control and healing. Most physicians now use proton pump inhibitors as first‐line treatment for many patients with acid‐peptic disorders, including erosive gastro‐oesophageal reflux disease (GERD), nonerosive reflux disease (NERD) and duodenal and gastric ulcers. Although proton pump inhibitors are often thought to be interchangeable, some differences have emerged in their pharmacological properties, which may be reflected in some aspects of clinical efficacy. Such differences include potency, speed of onset and duration of pH ‘holding times’. Helicobacter pylori has now been recognized as an important factor in the pathogenesis of acid‐peptic disorders. It is clear that H. pylori eradication can dramatically reduce the chronicity of gastric and duodenal ulcers, and accepted therapeutic regimens for H. pylori eradication now include proton pump inhibitors and two or more antibiotics. Although all accepted proton pump inhibitor‐based ‘triple therapies’ are roughly equivalent in efficacy, there is now a shortened regimen available that will potentially enhance compliance and decrease cost. This review examines the relative advantages of proton pump inhibitors vs. histamine2‐receptor antagonists in the context of acid suppression and in various gastric acid‐related diseases. A brief overview presents the pharmacodynamics and pharmacokinetics of the proton pump inhibitors with particular attention paid to rabeprazole, one of the newer drugs in its class.
Presence of monoclonal free light chains in the serum predicts risk of progression in monoclonal gammopathy of undetermined significance
Authors: Rajkumar S. Vincent , Kyle Robert A. , Therneau Terry M. , Clark Raynell J. , Bradwell Arthur R. , Melton L. Joseph , Larson Dirk R. , Plevak Matthew F. , Katzmann Jerry A.
Published: October 2004

We hypothesized that the presence of monoclonal free light chains (FLC) in the serum of patients with monoclonal gammopathy of undetermined significance (MGUS) is a marker of clonal evolution and a risk factor for progression. Forty‐seven patients with MGUS and documented progression to myeloma or related malignancy were compared with 50 age‐ and gender‐matched patients with MGUS and no evidence of progression after 5 or more years of follow‐up. The presence of an abnormal kappa/lambda FLC ratio in the serum was associated with a higher risk of MGUS progression (relative risk 2·5; 95% confidence interval: 1·6–4·0; P < 0·001).
Expression pattern of FCRL (FREB, FcRX) in normal and neoplastic human B cells
Authors: Masir Noraidah , Jones Margaret , Pozzobon Michela , Marafioti Teresa , Volkova Olga Y. , Mechetina Ludmila V. , Hansmann Martin‐Leo , Natkunam Yasodha , Taranin Alexander V. , Mason David Y.
Published: October 2004

FCRL (also known as FREB and FcRX) is a recently described member of the family of Fc receptors for immunoglobulin G (IgG). In the present study we analysed its expression in normal and neoplastic lymphoid tissue using immunohistochemical techniques. FCRL was preferentially expressed in a proportion of germinal centre cells and, more weakly, in mantle zone B cells. In addition, strong labelling was observed in marginal zone B cells in the spleen, representing one of the few markers for this cell type. The majority of cases of small B‐cell lymphoma, diffuse large B‐cell lymphoma and lymphocyte predominance Hodgkin's disease were positive for FCRL. However, the number of positive cells varied widely, and in consequence we could not define a cut‐off that distinguished subsets of diffuse large B‐cell lymphoma. Our results also showed that FCRL tended to be negative in T‐cell‐rich B‐cell lymphoma and in classical Hodgkin's disease. FCRL may therefore represent a novel marker for normal B cells (e.g. splenic marginal zone cells) and may also be useful as a potential marker of B‐cell neoplasms.