bluuebunny/crossref_metadata_2025_split huggingface dataset:
OPTIMIZATION OF AN IMMUNOFLUORESCENT ASSAY OF THE INTERNAL ENZYME RIBULOSE‐1,5‐BISPHOSPHATE CARBOXYLASE (RUBISCO) IN SINGLE PHYTOPLANKTON CELLS1
Authors: Orellana Mónica V. , Perry Mary Jane 
Published: October 2004

ABSTRACT Immunochemical probes are widely used to identih different species and to quantify and understand the role that different antigens play within cells. We optimized a single‐cell immunofluorescent assay for the carbon fixation enzyme ribulose‐1,5‐bisphosphate carboxylase (Rubisco) in order to quantify the enzyme by flow cytometry in phytoplankton cells. The criteria for optimization of the immunofluorescent assay for Rubisco in single cells included maximization of Rubisco immunogenicity, minimization of Rubisco diffusion out of the cells, minimization of cell breakage, and maximization of the cell labeling. Several fixatives (cross‐linkers and denaturing) and permeabilizing agents were tested on 26 species of phytoplankton. The only fixative / permeabilizing agent that fulfilled the criteria established for the assay was 96% ethanol. Phytoplankton cells collected from the field needed further treatment with a strong oxidant to permeabilize ethanolfixed cells and thus allow the antibody probe to access the Rubisco antigen. This study should have a general applicability to the study of other soluble photosynthetic antigens in single phytoplankton cells.
MORPHOSPECIES VS. GENOSPECIES IN TOXIC MARINE DINOFLAGELLATES: AN ANALYSIS OF GYMNODZNIUM CATENATUM/GYRODINIUM IMPUDICUM AND ALEXANDRIUM MINUTUM/A. LUSITANICUM USING ANTIBODIES, LECTINS, AND GENE SEQUENCES1
Authors: Costas Eduardo , Zardoya Rafael , Bautista Jose , Garrido Amando , Rojo Carmen , López‐Rodas Victoria 
Published: October 2004

ABSTRACT Morphological features are the predominant criteria used to define species of marine dinoflagellates. Taxonomic problems with some toxic groups has led to the implementation of molecular taxonomy techniques and development of a genospecies concept. As a result, the relationships between “morphospecies” and “genospecies” has been questioned. In this study, the genetic differentiation between two sets of closely related morphospecies, Gymnodinium catenatum Graham/Gyrodinium impudicum Fraga and Alexandrium minutum Halim/Alexandrium lusitanicum Balech, were analyzed. The extent of morphological differentiation existing within these two groups is of the same order of magnitude. Analysis of cell surface antigens detected by preadsorbed serum, cell surface glycan moieties detected by lectins and sequencing of the D9 and D10 domains of the Large‐subunit ribosomal RNA gene, showed that the extent of genetic differentiation existing between the dinofagellates Gymnodinium catenatum/Gyrodinium impudicum is substantial. Therefore, both morphological and genetic criteria resolve these organisms as two distinct entities. In contrast, Alexandrium minutum/Alexandrium lusitanicum were indistinguishable using the some suite of molecular markers. The findings demonstrated that classifications based on morphological criteria may be incongruous. On a practical level, molecular taxonomy provides useful tools to distinguish between morphologically similar microalgal species and furthermore can prevent misidentification of species such as Gymnodinium catenatum/Gyrodinium impudicum, a frequent occurrence when samples are fixed with Lugol's or formaldehyde solution.
ANALYSIS OF HETEROSIGMA CARTERAE1 (CHROMOPHYTA, RAPHIDOPHYCEAE) CHLOROPLAST rpoB GENE SEQUENCE2
Authors: Mangahas Jeff L. , Cattolico Rose Ann , Reynolds Ann E. 
Published: October 2004

ABSTRACT The rpoB gene encoding the β‐subunit of RNA Polymerase has been isolated from the chloroplast genome of the chromophytic alga Heterosigma carterae (Taylor 1992). The nucleotide sequence contains an open reading frame of 3348 bp, which encodes 1116 amino acids. The H. carterae rpoB gene structure is similar to that of chlorophytic chloroplast rpoB genes with respect to insertion‐deletion domains. However, several conserved residues found in all chlorophytic plants and bacterial rpoB genes have not been found in this alga. This is the first nonchlorophytic chloroplast rpoB gene to be analyzed, and our data provide insight concerning regions, and perhaps particular residues, that may be essential to chloroplast RNA polymerase function.
AN IN VITRO NITRATE REDUCTASE ASSAY FOR MARINE MACROALGAE: OPTIMIZATION AND CHARACTERIZATION OF THE ENZYME FOR FUCUS GARDNERI (PHAEOPHYTA)1
Authors: Hurd Catriona L. , Berges John A. , Osborne Josephine , Harrison Paul J. 
Published: October 2004

ABSTRACT Measurement of the activity of the enzyme nitrate reductase (NR) may provide a useful index of nitrogen metabolism in marine macroalgae. In several species, including Fucus gardneri P. C. Silva, in vitro assays previously failed to detect NR activity, necessitating the use of in situ (or so‐called“in vivo”) assays, which are more loosely controlled and lead to dafficulties in assessing enzyme characteristics such as the half‐saturation constant (Km). In this paper, we describe an in vitro NR assay developed for F. gardneri, in which tissue was homogenized using liquid nitrogen prior to the assay. In contrast to previous studies, enzyme activity was always detectable in F. gardneri collected directly from the field at levels up to 30 nmol nitrate converted to nitrite·min−1·g−1 wet weight. The effect of a variety of compounds, commonly added to NR extraction buffers, were tested. Additions of protease inhibitors, bovine serum albumin, and ethylenediamine tetraacetic acid had no consistent effects on NR activity, while polyvinyl pyrrolidone, potassium ferricyanide, and flavin adenine dinucleotide significantly decreased activity. The half‐saturation constant (Km) for NADH was 0.18 (± 0.05) mM and for nitrate, Km=0.99 (±0.41) mM. Significant NR activity was detected without the addition of nitrate, suggesting that internal pools of nitrate averaging approximately 20 μmol NO3−·g−1 wet weight were present in F. gardneri in February. The distribution of NR activity within the plant was highly variable between individuals, but activities were approximately 5‐fold lower in the stipe than in midregions. In plants freshly sampled from the field, NR activity increased 7‐fold from February to March, then fell to near‐February levels by April. These changes in activity may correspond to seasonal changes in growth rate. The assay, optimized for F. gardneri, was used in several different macroalgal species from different taxa: Porphyra sp., Coralina vancouveriensis Yendo, Ulva sp., Enteromorpha intestinalis (Linnaeus) Nees, Macrocystis integrifolia Bory; and Costaria costatum (C. Agardh) Saunders. For all species tested, NR activity was detectable and, except for one species (Porphya sp.), was equal to or greater than activities measured by other workers using in vivo or in vitro assays for plants under similar conditions.
EFFECT OF CURRENT VELOCITY ON THE DETACHMENT OF THALLI OF ULVA LACTUCA (CHLOROPHYTA) IN A NEW ZEALAND ESTUARY
Authors: Hawes Ian , Smith Rob 
Published: October 2004

ABSTRACT Experiments were undertaken in a recirculating flume to determine the relationships among water velocity, thallus area, drag, and the probability of thallus breakage or detachment in the foliose green alga Ulva lactuca L. In all specimens tested to breaking point, thalli detached from their bivalve substrates as a result of stipe breakage rather than in midthallus or by holdfast detachment. There was no relationship between thallus size and drag at which detachment occurred. Rather, the probability of detachment was normally distributed about a mean drag of 0. 70 N (95% confidence limits 0.55–0.85 N). Average breaking stress of stipes was 345 kN.m‐2 (95% cl 250–485 kN.m‐2). Similar results were obtained in field experiments where the horizontal force required to detach thalli was measured directly as 0.93 N (95% cl 0.69–1.15 N). Drag coefficients of plants were not constant with water velocity but increased up to 0.4 m.s‐1, declining exponentially at velocities above this. Empirical relationships were established between coefficient of drag and Reynold's number and, hence, among drag, thallus area and water velocity. These relationships permitted estimation of mean water velocity at which plants of a given area would detach.
GROWTH RESPONSES OF SEVERAL DIATOM SPECIES ISOLATED FROM VARIOUS ENVIRONMENTS TO TEMPERATURE
Authors: Suzuki Yoshihiro , Takahashi Masayuki 
Published: October 2004

ABSTRACTEight diatom species(Chaetoceros pseudocurvisetusMang., Stephanodiscus hantzschiiGrun., Skeletonema costatum (Grev.) Cleve, Asterionella formosaHass., Thalassiosira nordenskioeldiiCleve, Detonula confervacea (Cleve) Gran, Chaetocerossp., andNitzschia frigidaGrun.) were isolated from various temperature environments ranging from temperate to the Arctic, and their growth responses to temperature were determined. Each species grew over a different temperature range. The lower and upper limits of each species varied from −1.8° to 20° C and from 2° to 30° C, respectively. The width of the growth range of each species. also varied from 3.8° to 25° C, and the growth of these species was observed, as a whole, between a wide temperature range from −1.8° to 30° C.Within the growth temperature ranges, the growth rate of each species increased with temperature until reaching a maximum, which was followed by a steep decrease up to the upper limit of the growth range. As a result, each species showed a maximum rate at the temperature very near to the upper limit, which was generally higher than the isolation temperature. The specific growth rates were compared among the eight species. The interspecific maximum rate at each temperature exhibited an exponential increase with a Q10=1.48. The relative growth rates of each species were calculated by normalizing the specific growth rates with the interspecific maximum rate at each respective temperature. The higher relative growth rates tended to occur at the isolation temperature of each species, suggesting that temperature is a significant control on species distributions in nature.
INCORPORATION OF FRESHWATER RHODOPHYTA INTO THE CASES OF CADDISFLIES (TRICHOPTERA) FROM NORTH AMERICA
Authors: Sheath Robert G. , Müller Kirsten M. , Larson David J. , Cole Kathleen M. 
Published: October 2004

ABSTRACT Cases of larvae and pupae from six caddisfly (Insecta, Trichoptera) genera in three families from North America were observed to contain pieces of freshwater rhodophyte thalli. Seven genera of Rhodophyta, representing 13 species and 35 populations, were observed in this association. Four of the 25 species of Batrachospermum were incorporated into cases of Ochrotrichia (Hydroptilidae) and Agrypnia (Phryganeidae). Two of the three freshwater species of Bostrychia were used by Ochrotrichia larvae. Both Compsopogon coeruleus (Balbis) Mont. and C. prolificus Yadava et Kumano were present in the cases of Hydroptial (Hydroptilidae) and Ochrotrichia; Compsopogonopsis leptocladus (Mont.) Krishnamur‐thy was observed in the cases of Hydroptila. The more cartilaginous thalli of Lemanea fluviatilis (L.) C. Ag. and Tuomeya americana (Kütz.) Papenfuss were used by the brachycentrid larvae of Brachycentrus and Mi‐crasema. Lemanea and Paralemanea spp. were also in the cases of Dibusa angata Ross (Hydroptilidae). The architecture of each caddisfly case was studied with light and scanning electron microscopy. Strips of algae were fit together in a transverse, concentric, or spiralled fashion. Based on transmission electron micrographs, cortical cells of Lemanea and Tuomeya in the cases of Brachycentrus and Micrasema appeared to be healthy with intact chloroplasts and typical batrachospermalean pit plugs. Geographic distributions of each rhodophyte‐caddisfly association are given.
MOLECULAR STRUCTURE AND EVOLUTION OF THE CHLOROPLAST atpB/E GENE CLUSTER IN THE DIATOM ODONTELLA SINENSIS
Authors: Kroth‐Pancic Peter G. , Freier Ulrich , Strotmann Heinrich , Kowallik Klaus V. 
Published: October 2004

ABSTRACT We cloned and sequenced the chloroplast atpB/E gene cluster encoding the β‐ and εsubunits of the chloroplast ATPase, together with its flanking regions, in the centric diatom Odontella sinensis (Grev.) Grunow. This gene cluster, which was transcribed into a main transcript of 3.5 kb, was flanked by the genes ycf 3 (upstream atpB) and ORF 263 (downstream atpE), the latter being unknown from land plant chloroplasts. All reading frames were located on the same strand. In contrast to most higher plants, atpB and atpE in Odontella sinensis did not overlap but were separated from each other by 13 nucleotides (nts), similar to other chlorophyll a+c‐containing algae. Comparisons of atpB/E spacer regions from cyanobacteria, algae, and land plants indicate that separated atpB and atpE genes reflect a primitive rather than derived character. The spacer separating atpE and ORF 263 contained an inverted repeat sequence of 14 nts. Comparisons of inferred amino acid sequences from atpB of Odontella with known ATPase‐β sequences from other photosynthetic organisms revealed 75–91% identical amino acid residues. In contrast, the εsubunits exhibited 26–65% protein sequence conservation, with sequence identities around 40% within chlorophyll a+c‐containing algae. Relative to β‐subunits ofchlorophjtes (including land plants) and cyanobacteria, a gap of four amino acid residues was found close to the N‐terminus of ATPase‐β in Odontella. Phylogenetic trees constructed by maximum parsimony and distance matrix methods were consistent with a monophyletic origin of all extant plastid types from within the cyanobacterial radiation, but did not unequivocally delineate evolutionary affiliations among nongreen plastids.
USINGrbcL SEQUENCES TO TEST HYPOTHESES OF CHLOROPLAST AND THALLUS EVOLUTION IN CONJUGATING GREEN ALGAE (ZYGNEMATALES, CHAROPHYCEAE)
Authors: McCourt Richard M. , Karol Kenneth G. , Kaplan Susanne , Hoshaw Robert W. 
Published: October 2004

ABSTRACTSequences for the Rubisco large subunit (rbcL) gene were used to test hypotheses about the evolution of chloroplast shape and thallus type in genera of two families of conjugating green algae (Zygnematales): the Mesotaeniaceae (saccoderm desmids, mostly unicellular) and the Zygnemataceae (strictly filamentous). Unicellular (u) and filamentous (f) genera exhibit a series of three similar chloroplast shapes: ribbonlike (e.g. Spirotaenia [u], Spirogyra [f], and Sirogonium [f], laminate (e.g. Mesotaenium [u] and Mougeotia [f]), and twin‐stellate (e.g. Cylindrocystis [u] and Zygnema [f]. Two conflicting phylogenetic hypotheses have been proposed: 1) families are polyphyletic constructs drawn from three lineages, each with unicellular and filamentous taxa characterized by a specific chloroplast shape; or 2) unicells form one monophyletic lineage (Mesotaeniaceae) and filaments form another (Zygnemataceae), with some chloroplast shapes independently derived. The rbcL data strongly refute hypothesis 2 (monophyly of the two traditional families) and support hypothesis 1 in part. Parsimony, maximum likelihood, and neighbor‐joining analyses of the rbcL data strongly support monophyly of a clade containing taxa with ribbonlike chloroplasts and, to a lesser extent, monophyly of a second clade of the four genera with the other two chloroplast shapes. Two saccoderm genera (Roya, curved laminate chloroplasts; Netrium, “cucumber”‐shaped chloroplasts) are not members of either of these clades, but they are included in a monophyletic Zygnematales.
The prevalence of injecting drug use in a Russian city: implications for harm reduction and coverage
Authors: Platt Lucy , Hickman Matthew , Rhodes Tim , Mikhailova Larissa , Karavashkin Victor , Vlasov Alexander , Tilling Kate , Hope Vivian , Khutorksoy Mikhail , Renton Adrian 
Published: October 2004

ABSTRACTAim  This study sought to estimate the prevalence of injecting drug users (IDU) in Togliatti city and to examine the implications of these estimates for HIV prevalence and harm reduction.Design  Routine data sources of IDUs were identified. Covariate capture–recapture techniques were used on the individuals identified on the three data sources and used to estimate the number of IDU ‘not observed’ by the data sources, and thereby estimate the prevalence of IDU.Setting  Togliatti City, Samara Oblast, Russian Federation.Participants  IDUs recorded on three data sources (narcology records, HIV positive test results and police arrest data) during 2001.Measurements  Poisson regression models were fitted to the observed data, with interactions between data sources fitted to replicate ‘dependencies’ between those data sources. To select the best model the goodness of fit was approximated by χ2 distribution and the best‐fitting model was selected on the basis of standard information criteria and log likelihood ratio tests.Findings  The total estimated population of IDUs is 20 226 [95% confidence interval (CI): 16 971–24 749] giving a population prevalence of 5.4% (95% CI: 4.5–6.6%) of the registered population and 2.7% (95% CI: 2.4–3.5%) of the population (including migrants) aged 15–44 years. For every one IDU in contact with a service there were three out of contact.Conclusions  There  is  a  high  prevalence  of  IDU  which,  in  the  context  of  a fast‐emerging IDU‐associated HIV epidemic, will have serious public health implications.
Adherence to pharmacotherapy in patients with alcohol and opioid dependence
Authors: Weiss Roger D. 
Published: October 2004

ABSTRACTAims  An important factor that has thus far limited the effectiveness of pharmacotherapies for patients with alcohol and opioid dependence is poor adherence to medication regimens. This paper presents a review of issues related to medication adherence in patients with these substance use disorders.Design and methods  A literature review was conducted of English language publications relating to medication adherence among patients with alcohol or opioid dependence.Findings  The paper places the topic in the context of adherence difficulties among patients with a variety of chronic medical and psychiatric illnesses. Difficulties measuring adherence are discussed, and strategies to improve medication adherence are reviewed. These include specific interventions that prescribing clinicians can implement in their individual meetings with patients; the use of external reinforcers, such as positive and negative contingencies, and involvement of family members or significant others; and specific prescribing and dosing practices that may improve adherence.Conclusions  As the use of pharmacotherapy for substance‐dependent patients increases, rigorous and innovative approaches to encourage medication adherence should be sought.
The Bohr effect of haemoglobin in vertebrates: an example of molecular adaptation to different physiological requirements
Authors: Giardina B. , Mosca D. , De Rosa M. C. 
Published: October 2004

AbstractThe Bohr effect, i.e. the pH dependence of the oxygen affinity of haemoglobins (Hbs) from a variety of vertebrates, and its modulation by temperature and other heterotropic effectors has been reviewed. Haemoglobins from vertebrates were not reviewed following the usual classification (i.e. mammals, birds, etc.); instead we have selected several key examples of animals, which are confronted with a similar environmental situation therefore displaying a similar life style. Hence, the paper starts from a description of the general concepts at the basis of the Bohr effect as exemplified by human HbA and goes towards the analysis of the modulation mechanisms which have been observed in different animals in response to the needs induced by: (i) life in cold environments; (ii) diving behaviour; (iii) flight; and (iv) aquatic life. The emerging picture indicates a complex organization of the information contained in the Hb molecule, the oxygen‐binding properties of which depend both on the intrinsic characteristics of the protein and on its heterotropic interactions with ligands such as protons (Bohr effect), small anions like chloride and organic phosphates. In addition, each one of the functional effects induced by binding of a given effector appears to be under the strict control of temperature that enhances or decreases its relative weight with respect to all the others. It is just by this sophisticated network of interactions that the Hb molecule is able to satisfy the physiological requirements of a multitude of organisms without changing dramatically its quaternary structure.
Positive inotropic and sustained anti‐β‐adrenergic effect of diadenosine pentaphosphate in human and guinea pig hearts. Role of dinucleotide receptors and adenosine receptors
Authors: Arvola L. , Bertelsen G. , Hassaf D. , Ytrehus K. 
Published: October 2004

AbstractAim:  Diadenosine polyphosphates are present intracellularly and in extracellular fluid due to release from secretory vesicles in platelets, chromaffin cells and other cells. This study investigates effects of diadenosine pentaphosphate (AP5A) on heart muscle function.Methods:  Contractile force amplitude and action potential duration at 90% repolarization (APD90) were measured after challenge with AP5A 50 μm or isoproterenol 50–70 nM in guinea pig papillary muscles. Isoproterenol was given immediately after AP5A‐exposure or after 45 min washout. AP5A was combined with antagonists to the purinergic P2 receptor (suramin 100 μm), the dinucleotide receptor [diinosine pentaphosphate 30 μm (IP5I)] or adenosine receptors [8‐(P‐sulfophenyl) theophylline 50 μm (8‐SPT)].Results:  Results are %‐change (mean ± SEM) from value before exposure. AP5A increased contractile force by 22 ± 3%* (*P < 0.05), and IP5I abolished this. AP5A prolonged APD90 by 7 ± 2%*. AP5A significantly reduced response to isoproterenol acutely from 31 ± 4* (controls) to 9 ± 4% and after 45 min washout from 61 ± 14* (controls) to 16 ± 5%. 8‐SPT abolished the sustained effect. Increase in contractile force by AP5A was confirmed in human atria trabecula preparations.Conclusion: AP5A increased contractile force and prolonged APD90. Contractile force increased by stimulation of the dinucleotide receptor in guinea pig myocardium. The sustained anti‐β‐adrenergic effect of AP5A was due to adenosine receptor stimulation.
Review article: relief of symptoms in gastric acid‐related diseases – correlation with acid suppression in rabeprazole treatment
Authors: Miner P. 
Published: October 2004

SummarySymptom relief is one of the key goals in the management of gastric acid‐related disorders such as gastro‐oesophageal reflux disease (GERD), including nonerosive reflux disease (NERD), and duodenal and gastric ulcer. Whereas heartburn and regurgitation are classic symptoms of GERD, duodenal and gastric ulcers are associated with epigastric pain. The relationship between gastric acid and the presence of symptoms correlates well in GERD and duodenal ulcer, but not in gastric ulcer and NERD. Nevertheless, in all these disorders, gastric acid is considered a key pathogenic element, and acid suppression remains central to therapy. With their profound, prolonged effect on acid inhibition, proton pump inhibitors are considered the first‐choice therapy for these disorders. Rabeprazole is a newer generation proton pump inhibitor that suppresses the gastric proton pump and acid secretion more rapidly than does omeprazole, lansoprazole or pantoprazole. In clinical trial settings, rabeprazole provided fast and sustained symptom relief, which can help ensure patient acceptance of therapy and aid in patient compliance.