bluuebunny/crossref_metadata_2025 huggingface dataset:
AUTOTROPHIC GROWTH AND PHOTOACCLIMATION IN KARLODINIUM MICRUM (DINOPHYCEAE) AND STOREATULA MAJOR (CRYPTOPHYCEAE)1
Authors: Adolf Jason E. , Stoecker Diane K. , Harding Lawrence W.
Published: November 2003

We compared autotrophic growth of the dinoflagellate Karlodinium micrum (Leadbeater et Dodge) and the cryptophyte Storeatula major (Butcher ex Hill) at a range of growth irradiances (Eg). Our goal was to determine the physiological bases for differences in growth–irradiance relationships between these species. Maximum autotrophic growth rates of K. micrum and S. major were 0.5 and 1.5 div.·d−1, respectively. Growth rates were positively correlated with C‐specific photosynthetic performance (PPC, g C·g C−1·h−1) (r2=0.72). Cultures were grouped as light‐limited (LL) and high‐light (HL) treatments to allow interspecific comparisons of physiological properties that underlie the growth–irradiance relationships. Interspecific differences in the C‐specific light absorption rate (EaC, mol photons·g C−1·h−1) were observed only among HL acclimated cultures, and the realized quantum yield of C fixation (φC(real.), mol C·mol photons−1) did not differ significantly between species in either LL or HL treatments. The proportion of fixed C that was incorporated into new biomass was lower in K. micrum than S. major at each Eg, reflecting lower growth efficiency in K. micrum. Photoacclimation to HL in K. micrum involved a significant loss of cellular photosynthetic capacity (Pmaxcell), whereas in S. major, Pmaxcell was significantly higher in HL acclimated cells. We conclude that growth rate differences between K. micrum and S. major under LL conditions relate primarily to cell metabolism processes (i.e. growth efficiency) and that reduced chloroplast function, reflected in PPC and photosynthesis–irradiance curve acclimation in K. micrum, is also important under HL conditions.
HERITABILITY OF MANTLE AREOLAR CHARACTERS IN AULACOSEIRA SUBARCTICA (BACILLARIOPHYTA)1
Authors: Edgar Stacy McBride , Theriot Edward C.
Published: November 2003

Are size and arrangement of valve mantle areolae in Aulacoseira Thwaites adapted to light intensity? To test one criterion demonstrating an adaptation, heritability experiments were run on isolates of Aulacoseira subarctica (Müller) Haworth. Several clones of A. subarctica were isolated from Yellowstone Lake (Wyoming, USA), Lewis Lake (Wyoming), and East Rosebud Lake (Montana, USA). Two to four clones from each lake were grown in batch cultures under three irradiance levels: 2, 11.4, and 115 μmol photons·m−2·s−1. Five randomly chosen valves for each of two replicates of each clone were examined using a scanning electron microscope for a total of 300 valves. Size measurements were taken for each valve examined, and images of mantle areolae were captured on film at a magnification of 20,000×. Each image was digitized, and quantitative morphometric areolar characters were measured. A quantitative genetic analysis was performed within each light environment for the mean area of the external opening of mantle areolae, the mean distance between areolae within pervalvar striae, and the mean distance between pervalvar striae. Resulting estimates of heritability from among‐lake and within‐lake analyses indicate that all three mantle areolar characters could presently respond to selection and thus have potentially done so in the past.
PHYTOPLANKTON PLASMA MEMBRANE REDOX ACTIVITY: EFFECT OF IRON LIMITATION AND INTERACTION WITH PHOTOSYNTHESIS1
Authors: Davey Margaret S. , Suggett David J. , Geider Richard J. , Taylor Alison R.
Published: November 2003

Phytoplankton plasma membrane electron transport activity was determined by monitoring the reduction of the impermeant artificial electron acceptor ferricyanide in a range of diatoms. The results revealed that constitutive plasma membrane electron transport activity of marine diatoms is high compared with chlorophytes and higher plant cells. Diatom plasma membrane electron transport activity was not significantly increased by iron limitation. This lack of induction on iron limitation indicates that diatoms have an iron acquisition strategy that is distinct from chlorophytes and the dicotyledon higher plants that exhibit marked increases in plasma membrane ferricyanide reductase activity on iron limitation. The interaction of the constitutive plasma membrane electron transport with photosynthesis was also investigated. We found that 1) ferricyanide reduction at the plasma membrane was progressively inhibited in response to increasing irradiances; 2) the presence of extracellular ferricyanide, but not the reduced couple ferrocyanide, caused a marked inhibition of carbon fixation at high irradiance; and 3) extracellular electron acceptors ferricyanide and hexachloroiridate (but not ferrocyanide) induced an immediate and reversible decrease in fluorescence yields (Fo and Fm). The extent to which extracellular electron acceptors affected CO2 fixation, Fo, and Fm was related to the level of constitutive ferricyanide reductase activity, the species with highest ferricyanide reduction rates being most sensitive. The data suggest that consumption of electrons and/or reductant at the plasma membrane by external acceptors may compete directly with CO2 fixation for electrons, alter cytosolic‐chloroplast redox poise, and/or induce a redox‐signaling cascade that alters photosynthetic metabolism.
A MORPHOLOGICAL STUDY AND TAXONOMIC REASSESSMENT OF THE GENERITYPE SPECIES IN THE GRACILARIACEAE1
Authors: Liao Lawrence M. , Hommersand Max H.
Published: November 2003

We investigated the reproductive morphology of representative material corresponding to the type species of each of the described genera presently placed in synonymy underGracilaria. From these observations and published studies of recognized genera, 10 species groups are identified in the Gracilariaceae based on spermatangial type and cystocarp development. Actual or potential generic names are given in brackets after each group: 1) abscissa group (Melanthalia), 2) flabellata group (Curdiea), 3) lemaneiformis group (Gracilariopsis), 4) chilensis group, 5) edulis group (Plocaria/Polycavernosa), 6) urvillei group (Hydropuntia), 7) crassissima group, 8) salicornia group (Corallopsis), 9) gracilis group, and 10) bursa‐pastoris group (Gracilaria).Tyleiophorawas shown to belong to the bursa‐pastoris group. The type species of the parasitic generaGracilariophilaandCongracilariaare closely related to their host species. Species assemblages recognized here based on morphological evidence received moderate to strong bootstrap support in recently published molecular phylogenies. Further studies may show that some groups correspond to genera, whereas others do not merit generic status.
MATING SYSTEM, SEXUAL REPRODUCTION, AND AUXOSPORULATION IN THE ANOMALOUS RAPHID DIATOM EUNOTIA (BACILLARIOPHYTA)1
Authors: Mann David G. , Chepurnov Victor A. , Idei Masahiko
Published: November 2003

The diatom genus Eunotia is unusual among raphid diatoms in having a raphe system consisting of two short slits that are not integrated into the primary pattern center. This and other characteristics, particularly the presence of rimoportulae, are consistent with the hypothesis that Eunotia is a basal lineage within the raphid group. We studied auxosporulation in E. bilunaris (Ehrenberg) Mills and E. tropica Hustedt for comparison with other raphid pennate diatoms and with araphid pennates; E. bilunaris was studied in parental and F1 generations. Like araphid pennates, E. bilunaris and E. tropica are heterothallic. Clones of the same mating type did not interact sexually, and intraclonal sexual reproduction was absent or very rare. Clones retained the same sex throughout the life cycle, as shown by experiments using abrupt size reduction to produce clones of similar age but different size and using subclones derived from a single initial cell within six mitotic generations. Unlike in araphid pennate diatoms, in the Eunotia species the gametes are not visibly or behaviorally differentiated. Gametogenesis is merogenous, because the gametangium formed a supernumerary cell as well as a single gametic cell, both undergoing meiosis II to form a surviving functional nucleus and a nucleus that quickly degenerated. Plasmogamy is via papillae that grew out toward each other from the ends of the gametangia to create a copulation canal. After plasmogamy, the gametes moves bodily into the copulation canal, producing an elongate zygote, which expands to form a curved sausage‐like auxospore.
TAKAYAMA GEN. NOV. (GYMNODINIALES, DINOPHYCEAE), A NEW GENUS OF UNARMORED DINOFLAGELLATES WITH SIGMOID APICAL GROOVES, INCLUDING THE DESCRIPTION OF TWO NEW SPECIES1
Authors: De salas Miguel F. , Bolch Christopher J. S. , Botes Lizeth , Nash Geraldine , Wright Simon W. , Hallegraeff Gustaaf M.
Published: November 2003

A new potentially ichthyotoxic dinoflagellate genus, Takayama de Salas, Bolch, Botes et Hallegraeff gen. nov., is described with two new species isolated from Tasmanian (Australia) and South African coastal waters: T. tasmanica de Salas, Bolch et Hallegraeff, sp. nov. and T. helix, de Salas, Bolch, Botes et Hallegraeff, sp. nov. The genus and two species are characterized by LM and EM of field samples and laboratory cultures as well as large subunit rDNA sequences and HPLC pigment analyses of several cultured strains. The new Takayama species have sigmoid apical grooves and contain fucoxanthin and its derivatives as the main accessory pigments. Takayama tasmanica is similar to the previously described species Gymnodinium pulchellum Larsen, Gyrodinium acrotrochum Larsen, and G. cladochroma Larsen in its external morphology but differs from these in having two ventral pores, a large horseshoe‐shaped nucleus, and a central pyrenoid with radiating chloroplasts that pass through the nucleus. It contains gyroxanthin‐diester and a gyroxanthin‐like accessory pigment, both of which are missing in T. helix. Takayama helix has an apical groove that is nearly straight while still being clearly inflected. A ventral pore or slit is present. It has numerous peripheral, strap shaped, and spiraling chloroplasts with individual pyrenoids and a solid ellipsoidal nucleus. The genus Takayama has close affinities to the genera Karenia and Karlodinium.
THE ROLE OF THE REACTIVITY AND CONTENT OF IRON OF AEROSOL DUST ON GROWTH RATES OF TWO ANTARCTIC DIATOM SPECIES1
Authors: Visser F. , Gerringa L. J. A. , Van der gaast S. J. , De baar H. J. W. , Timmermans K. R.
Published: November 2003

The atmosphere is widely recognized as a major source of Fe in the form of iron‐containing dust. This study provides the first experiments in which the impact of dust on the growth rates of single species of Antarctic diatoms was assessed under laboratory conditions. The dust was among others characterized by x‐ray powder diffraction analysis, analysis of total and amorphous Fe content, and dissolution rates of Fe in seawater. The amount of bioavailable Fe from the dust was determined, not via the complicated chemistry of Fe in seawater but by using diatoms as bioindicators for available Fe. Cultures of two large diatom species, Actinocyclus sp. and Thalassiosira sp., were amended with potential dust aerosols from two dust‐supplying regions, Namibia and Mauritania, and responses on growth rates were monitored. Apart from a difference in total Fe content, a difference in crystallinity existed in the Fe minerals of both dust types. The fraction of amorphous Fe was reflected in a higher reactivity/dissolution of Fe in seawater. The increase in growth rate upon dust addition was positively related with the amount of amorphous Fe in the dust and with the dissolution rate of Fe in seawater. However, compared with equal FeCl3 concentrations, the dissolved Fe from the dust was not completely available for the diatoms. Interestingly, the diatoms used only a small part of the dissolved Fe, demonstrating the importance of algae as bioindicators.
THE STRUCTURE AND NANOMECHANICAL PROPERTIES OF THE ADHESIVE MUCILAGE THAT MEDIATES DIATOM‐SUBSTRATUM ADHESION AND MOTILITY1
Authors: Higgins Michael J. , Molino Paul , Mulvaney Paul , Wetherbee Richard
Published: November 2003

We investigated the adhesive mucilage and mechanism of cell‐substratum adhesion of two benthic raphid diatoms, the marine species Craspedostauros australis E. J. Cox and the freshwater species Pinnularia viridis (Nitzsch) Ehrenberg. SEM images of P. viridis and C. australis cells revealed the presence of multistranded tethers that appear to arise along the raphe openings and extend for a considerable distance from the cell before forming a “holdfast‐like” attachment with the substratum. We propose that the tethers result from the elongation/stretching of composite adhesive mucilage strands secreted from raphes during the onset of cell adhesion and reorientation. Atomic force microscopy (AFM) force measurements reveal that the adhesive strands originating from the nondriving raphe of live C. australis and P. viridis are highly extensible and accumulate to form tethers. During force measurements tethers can be chemically stained and are seen to extend between the cantilever tip and a cell during elongation and relaxation. In most cases, AFM force measurements recorded an interaction with a number of adhesive strands that are secreted from the raphe. The force curves of C. australis and P. viridis revealed a sawtooth pattern, suggesting the successive unbinding of modular domains when the adhesive strands were placed under stress. In addition, we applied the “fly‐fishing” technique that allowed the cantilever, suspended a distance above the cell, to interact with single adhesive strands protruding from the raphe. These force curves revealed sawtooth patterns, although the binding forces recorded were in the range for single molecule interactions.
RECRUITMENT AND PELAGIC GROWTH OF GLOEOTRICHIA ECHINULATA (CYANOPHYCEAE) IN LAKE ERKEN1
Authors: Karlsson‐elfgren Irene , Rydin Emil , Hyenstrand Per , Pettersson Kurt
Published: November 2003

Different parameters in the life cycle of the colony forming cyanobacterium Gloeotrichia echinulata (J.E. Smith) Richter was evaluated in Lake Erken, Sweden. Recruitment of colonies from the sediments and pelagic abundance were measured during 2 years. These data were then used in a model to evaluate and estimate parameters of the life cycle. In our study, recruitment alone only contributed to a small part (<5%) of the maximum G. echinulata abundance that occurred during late summer. However, recruitment from shallow sediments forms the important seed for the pelagic population. Together with measured rates of migration from the sediment, variations in either pelagic colony division rate or pelagic residence time could explain variations in the measured abundance of G. echinulata in situ.
PLASMOLYSIS, HECHTIAN STRAND FORMATION, AND LOCALIZED MEMBRANE‐WALL ADHESIONS IN THE DESMID, CLOSTERIUM ACEROSUM (CHLOROPHYTA)1
Authors: Domozych David S. , Roberts Rachael , Danyow Carey , Flitter Rebecca , Smith Brennan , Providence Kirwin
Published: November 2003

Closterium acerosum Ehrenberg (Chlorophyta) produced a distinct network of thin cytoplasmic strands, or Hechtian strands, upon controlled plasmolysis in a sucrose solution. The strands persisted for 30 min or longer and could be visualized with both LM and EM. Near the plasma membrane of the polar zones of plasmolyzing protoplasts, the strands formed a “lattice”‐like arrangement with interstrand spacing of 120–130 nm. The strands terminated at the fibrous zone of the inner cell wall stratum. Although actin cables could be found attached to the plasma membrane upon rhodamine phalloidin labeling of membrane ghosts, neither microfilaments nor microtubules were found in Hechtian strands at any stage of development. The formation of strands was not disrupted by centrifugation at 8000 g or by repeated cycles of plasmolysis‐deplasmolysis. Application of microtubule‐ or microfilament‐affecting agents or various proteolytic/polysaccharide‐degrading enzymes did not disrupt the formation of strands. Cold treatment of cells resulted in the formation of Hechtian strands.
PHOTOSYNTHETIC UTILIZATION OF INORGANIC CARBON IN THE ECONOMIC BROWN ALGA, HIZIKIA FUSIFORME (SARGASSACEAE) FROM THE SOUTH CHINA SEA1
Authors: Zou Dinghui , Gao Kunshan , Xia Jianrong
Published: November 2003

The mechanism of inorganic carbon (Ci) acquisition by the economic brown macroalga, Hizikia fusiforme (Harv.) Okamura (Sargassaceae), was investigated to characterize its photosynthetic physiology. Both intracellular and extracellular carbonic anhydrase (CA) were detected, with the external CA activity accounting for about 5% of the total. Hizikia fusiforme showed higher rates of photosynthetic oxygen evolution at alkaline pH than those theoretically derived from the rates of uncatalyzed CO2 production from bicarbonate and exhibited a high pH compensation point (pH 9.66). The external CA inhibitor, acetazolamide, significantly depressed the photosynthetic oxygen evolution, whereas the anion‐exchanger inhibitor 4,4′‐diisothiocyano‐stilbene‐2,2′‐disulfonate had no inhibitory effect on it, implying the alga was capable of using HCO3− as a source of Ci for its photosynthesis via the mediation of the external CA. CO2 concentrations in the culture media affected its photosynthetic properties. A high level of CO2 (10,000 ppmv) resulted in a decrease in the external CA activity; however, a low CO2 level (20 ppmv) led to no changes in the external CA activity but raised the intracellular CA activity. Parallel to the reduction in the external CA activity at the high CO2 was a reduction in the photosynthetic CO2 affinity. Decreased activity of the external CA in the high CO2 grown samples led to reduced sensitiveness of photosynthesis to the addition of acetazolamide at alkaline pH. It was clearly indicated that H. fusiforme, which showed CO2‐limited photosynthesis with the half‐saturating concentration of Ci exceeding that of seawater, did not operate active HCO3− uptake but used it via the extracellular CA for its photosynthetic carbon fixation.
COMPLEX GENE STRUCTURE OF THE FORM II RUBISCO IN THE DINOFLAGELLATE PROROCENTRUM MINIMUM (DINOPHYCEAE)1
Authors: Zhang Huan , Lin Senjie
Published: November 2003

We analyzed the unusually complex organization of the nuclear‐encoded (form II) RUBISCO gene in the dinoflagellate Prorocentrum minimum (Parvillard) Schiller by intensive genomic DNA and cDNA sequencing and Western blotting. Over 10 transcribed units (TUs) were detected, which varied dramatically in their 3′ untranslated region. Each TU appeared to contain four tandem copies of the RUBISCO coding region (1.46 kb each; coding unit, or CU) interspersed by a 63‐bp spacer; the four CUs in each TU were cotranscribed and apparently cotranslated to a tetrameric polyprotein that may undergo successive cleavage steps to yield mature RUBISCO. By means of real‐time PCR analysis, it was estimated that each of the P. minimum genome harbored 148±16 CUs. Although nucleotide sequences varied by 1%–9% among the detected CUs, their inferred amino acid sequences were essentially identical. Our results suggest that the complex structure of Pmrbc has been derived from extensive and repeated gene duplications, an evolutionary process that has also been observed for other dinoflagellate genes.
VECTORIAL LABELING OF DINOFLAGELLATE CELL SURFACE PROTEINS1
Authors: Bertomeu Thierry , Woodland hastings J. , Morse David
Published: November 2003

Our objective was to identify cell surface proteins in the dinoflagellate Lingulodinium polyedrum. Proteins on the surface of living cells that had regions exposed to the external medium were labeled with Na125I. After partial purification of membrane proteins and analysis by two‐dimensional gel electrophoresis and autoradiography, a protein of roughly 43 kDa was found to have incorporated the radiolabel. This protein was cloned using a combination of protein microsequencing and PCR amplification. The derived protein sequence in the cDNA has a signal peptide at the N‐terminal end of the protein and thus represents the first plasma membrane protein ever reported for a dinoflagellate. The function of the protein is unknown, but its cloning provides a proof of principle for the general use of vectorial labeling in identifying cell surface proteins of marine algae.
ISOLATION AND CHARACTERIZATION OF A CELL WALL‐DEFECTIVE MUTANT OF CHLAMYDOMONAS MONOICA (CHLOROPHYTA)1
Authors: Fuentes Cesar , Vanwinkle‐swift Karen
Published: November 2003

Cell wall–defective strains of Chlamydomonas have played an important role in the development of transformation protocols for introducing exogenous DNA (foreign genes or cloned Chlamydomonas genes) into C. reinhardtii. To promote the development of similar protocols for transformation of the distantly related homothallic species, C. monoica, we used UV mutagenesis to obtain a mutant strain with a defective cell wall. The mutant, cw‐1, was first identified on the basis of irregular colony shape and was subsequently shown to have reduced plating efficiency and increased sensitivity to lysis by a non‐ionic detergent as compared with wild‐type cells. Tetrad analysis of crosses involving the cw‐1 mutant confirmed 2:2 segregation of the cw:cw+ phenotypes, indicating that the wall defect resulted from mutation of a single nuclear gene. The phenotype showed incomplete penetrance and variable expressivity. Although some cells had apparently normal cell walls as viewed by TEM, many cells of the cw‐1 strain had broken cell walls and others were protoplasts completely devoid of a cell wall. Several cw‐1 isolates obtained from crosses involving the original mutant strain showed a marked enhancement of the mutant phenotype and may prove especially useful for future work involving somatic cell fusions or development of transformation protocols.
Comparison of various dimethylsulphoxide‐containing solutions for cryopreservation of leucoreduced platelet concentrates
Authors: Dijkstra‐Tiekstra M. J. , De Korte D. , Pietersz R. N. I. , Reesink H. W. , Van Der Meer P. F. , Verhoeven A. J.
Published: November 2003

Background and Objectives  Leucoreduced platelet concentrates (LR‐PCs) can be stored at 20–24 °C for 5–7 days. When LR‐PCs are cryopreserved they can be stored for several years. For cryopreservation to become applicable in blood‐bank practice, an off‐the‐shelf cryoprotectant is needed that can be added to the LR‐PC in a sterile manner. For this, we varied the composition of the cryopreservation medium and studied various parameters of cryopreserved LR‐PCs for up to 24 h after thawing at room temperature.

Materials and Methods  LR‐PCs in plasma or Composol were concentrated and divided into 2 units. To each unit, an equal part of 10% dimethylsulfoxide (DMSO) in plasma, Composol with or without 5% albumin, or GPO (pasteurized plasma‐protein solution) was added. Freezing occurred at 1 °C/min and LR‐PCs were placed in the vapour phase of nitrogen. LR‐PCs were thawed at 37 °C and stored at room temperature. LR‐PCs were tested for morphology, platelet recovery, swirling effect, and activation antigens at various time‐points thereafter.

Results  LR‐PCs in 100%, 65% and 50% plasma supplemented with Composol showed good morphology scores (> 250), limited CD62P expression (< 35%), low CD63 expression (< 20%) and a swirling effect of about 2, at 24 h after thawing. At the same time‐point, platelet recovery was > 80% under all conditions and CD42b expression varied between 70 and 85%. Results of LR‐PCs in 15% plasma and Composol, with or without plasma substitutes, were not acceptable at 24 h after thawing, i.e. the morphology score was < 200 and the CD62P expression was > 40%.

Conclusions  A minimum of 50% plasma in the cryopreserved LR‐PC is necessary to maintain an acceptable in vitro quality of platelets up to 24 h after thawing. Composol is a good candidate for using to prepare an off‐the‐shelf cryoprotectant.
Prenatal genotyping ofRHDandSRYusing maternal blood
Authors: Randen I. , Hauge R. , Kjeldsen‐Kragh J. , Fagerhol M. K.
Published: November 2003

Background and Objectives The aim of the study was to perform fetalRHDgenotyping in maternal plasma using a fluorescent polymerase chain reaction (PCR) technique. Duplex PCR, amplifyingRHDandSRYin the same tube, was undertaken. The effect of varying storage temperatures on the concentration of fetal DNA was investigated in a separate study involving 10 RhD‐negative pregnant women.

Materials and Methods Primers and probes for theRHDgene's exon 7 and the sex‐determining region, Y, were designed, and monoplex and duplex PCR were performed. Blood samples from 10 RhD‐negative women were split into four and treated in four different ways before measuring the concentration of fetal DNA by quantitative PCR.

Results DNA extracted from the plasma of 114 RhD‐negative pregnant women was tested for the presence of fetalRHD. The discrepancy between genotyping and serological RhD typing of the babies postpartum was 8% when counting one positive replicate as a positive result. Duplex PCR, amplifyingRHDandSRYin the same tube, showed a reduced sensitivity for amplification of theSRYgene segment. There was a statistically significant reduction of fetal DNA in blood samples stored at room temperature for 48 h compared with the same sample stored at a temperature of < 10 °C for the same length of time.

Conclusions This method is not suitable for routine analysis because of the lack of a positive control forRHD‐negative female fetuses and a decrease in PCR sensitivity when performing duplex PCR. Fetal DNA in maternal plasma is better preserved when the blood sample is kept cool.
Tolerance of granulocyte donors towards granulocyte colony‐stimulating factor stimulation and of patients towards granulocyte transfusions: results of a multicentre study
Authors: Bux J. , Cassens U. , Dielschneider T. , Duchscherer M. , Edel E. , Eichler H. , Haas C. , Moog R. , Peschke H. , Peters C. , Ryzenkov I. , Schlenke P. , Ullrich H. , Wiesneth M.
Published: November 2003

Data of 507 granulocyte donations from 183 donors were evaluated. No severe granulocyte colony‐stimulating factor (G‐CSF)‐related side‐effects were observed. Three donors complained of severe itching following infusion of hydroxyethyl starch (HES). A high proportion (85%) of the donors stated that they would donate granulocytes again. The mean granulocyte yield was 4·3 × 1010. High‐molecular‐weight HES resulted in a significantly higher yield compared with low‐molecular‐weight HES. Mild, but no severe, adverse transfusion reactions were observed in 16% of the recipients. A leucocyte alloimmunization rate of 24% was found. G‐CSF stimulation and transfusion of G‐CSF‐mobilized granulocytes were well tolerated by donors and recipients, respectively.
Effect of composition and complexity of dentin‐bonding agents on operator variability – analysis of gap formation using confocal microscopy
Authors: Jacobsen Thomas , Söderholm Karl‐Johan M. , Yang Mark , Watson Timothy F.
Published: November 2003

The variability of gap formation due to different operators and bonding agents around dentin‐bonded composites in cylindrical cavities (internal diameter, 3 mm; depth, 1 mm; n = 210) was evaluated in vitro. Seven dentists evaluated two experimental bonding systems (A & B) and one commercial product (C) by each treating 10 teeth with each system. One of the investigators restored all cavities with composite (Z100, 3M ESPE) and removed excess material to expose the cavity margins. After storage in water for 1 wk, the maximum gap‐width was measured using a confocal microscope and statistically analysed. The relative gap‐widths (%) for the three bonding systems were not statistically different. Means ± SD were 0.18 ± 0.06, 0.19 ± 0.08, and 0.20 ± 0.06 for groups A, B, and C, respectively. The variation caused by the operator–material interaction was significant. When the operator's variability (SD) within the different materials was examined, group C displayed a significantly lower variability than the other two. It was concluded that the operator variable is a more important consideration than the material variable. The self‐etching system performed better than the more complex A and B systems when variability rather than gap size was considered.
Non‐contact removal of coadhering and non‐coadhering bacterial pairs from pellicle surfaces by sonic brushing and de novo adhesion
Authors: Busscher H. J. , Rustema‐Abbing M. , Bruinsma G. M. , De Jager M. , Gottenbos B. , Van Der Mei H. C.
Published: November 2003

Coadhesion between oral microbial pairs is an established factor in the spatiotemporal development and prevalence of mixed‐species communities in early dental plaque in vivo. This study compares removal and de novo adhesion of pairs of coadhering and non‐coadhering oral actinomyces and streptococci by sonic brushing on salivary pellicles in a non‐contact mode as a function of the distance between the brush and the pellicle surface in vitro. First, actinomycetes were adhered to a pellicle surface, after which streptococci suspended in saliva were allowed to adhere. Removal was examined by non‐contact, sonic brushing with a wetted brush on a either a wetted or a substratum immersed to a depth of 7 mm. After brushing, de novo adhesion of streptococci to brushed pellicles was studied. For coadhering and non‐coadhering pairs, 34% and 9%, respectively, of the adhering bacteria were involved in aggregates comprising more than 10 organisms. Non‐contact, sonic brushing removed up to 99% of the adhering bacteria, regardless of the state of immersion of the substratum. Bacterial removal decreased with increasing distance of up to 6 mm between brush and pellicle surface. For the non‐coadhering pair, subsequent exposure of pellicles to a streptococcal suspension yielded about 6% of bacteria involved in large aggregates. Alternatively, de novo adhesion of the coadhering streptococcal strain to pellicles brushed on the wetted substratum yielded 31% of bacteria involved in large aggregates, but after brushing the immersed substratum only 12% of the adhering bacteria were found in large aggregates. It is concluded that non‐contact sonic brushing, under immersion, removes high percentage of adhering bacterial pairs up to a distance of 6 mm between the brush and the pellicle surface. However, non‐contact, sonic brushing with only a thin wet film on the substratum may leave footprints to which streptococci preferentially adhere.
Oral health‐related quality of life in Germany
Authors: John Mike T. , LeResche Linda , Koepsell Thomas D. , Hujoel Philippe , Miglioretti Diana L. , Micheelis Wolfgang
Published: November 2003

The prevalence of impaired oral health‐related quality of life (OHRQoL) in Germany is unknown. The aim was to determine the OHRQoL distribution in the population and to derive population‐based norms. OHRQoL was measured using the German version of the Oral Health Impact Profile (OHIP‐G, 53 items) which was administered in a personal interview to 2050 subjects (response proportion: 60%) 16–79 yr of age. Subjects were sampled using a multistage sampling technique in a national survey. Prevalence was calculated for any impairment on the item (OHIP answer categories ranging from ‘hardly ever’ to ‘very often’) and for frequent problems (categories ‘fairly often’ and ‘very often’). Norms for the OHIP‐G summary score (sum of all item responses in the English‐language OHIP, range 0–196) were described by percentiles. Past‐month prevalence of any impairment in OHRQoL ranged from 13% to 46% across all items. Frequent problems were rare (≤ 6% for all items). Among subjects without dentures, 50% of the population had ≥ 5 OHIP‐G score points and 10% had ≥ 38 points. For subjects with removable dentures the scores were 15 and 60 points, respectively, and for subjects with complete dentures, 23 and 85 points, respectively. The results provide the first overview of impaired OHRQoL in Germany.
Viscoelastic properties of bovine retrodiscal tissue under tensile stress‐relaxation
Authors: Tanaka Eiji , Hanaoka Koichi , Tanaka Masao , Van Eijden Theo , Iwabe Tatsunori , Ishino Yoshihiro , Sasaki Akiko , Tanne Kazuo
Published: November 2003

To test the hypothesis that the condylar part of the retrodiscal tissue of the temporomandibular joint exhibits resistance to tensile force, we investigated its viscoelastic properties and stress‐relaxation behavior under tension. Ten specimens were tested. Stress‐relaxation tests were conducted from four different initial stress levels. The tissue exhibited a non‐linear stress–strain relationship, which could be represented by a bilinear relation of two line segments. The stress‐relaxation curves showed a marked drop in load during the initial 10 s and after 2 min the stress reached an almost steady non‐zero level. This feature can be well represented by Kelvin's model. It is concluded that the condylar part of the retrodiscal tissue (a) exhibits a non‐linear strain‐dependent viscoelastic behavior (b), has a great capacity for energy dissipation and resistance to tensile forces, and (c) contributes to maintain the position of the disc relative to the condyle during jaw closing.
Formation of Candida albicans biofilms on non‐shedding oral surfaces
Authors: Lamfon Hanadi , Porter Stephen R. , McCullough Michael , Pratten Jonathan
Published: November 2003

The aim of this investigation was to determine the ability of Candida albicans to form biofilms on enamel, dentine and denture acrylic of various surface roughnesses. Biofilms of C. albicans were grown on various materials in a constant depth film fermenter (CDFF) and maintained with artificial saliva. Enamel, dentine and denture acrylic were prepared to the same surface roughness using silicon carbide grit. In a separate experiment, denture acrylic was prepared to different surface roughnesses. At various intervals, the materials were removed from the CDFF, the biofilms disrupted and the number of yeast and hyphae present determined. The total number of yeast cells present on enamel was higher than either dentine or acrylic. The highest numbers of yeast cells were found on the roughest surfaces at 6 h; however, higher numbers of hyphae were found on enamel at 6 h and 24 h. Confocal laser scanning microscopy images revealed that the maturation of biofilms on denture acrylic may be dependent upon hyphal cells. The results of the present study show that both the type of surface and their roughness affect the initial formation and subsequent structure of developing of C. albicans biofilms.
CGRP1 and NK1 receptors in postnatal, developing rat dental tissues
Authors: Vandevska‐Radunovic Vaska , Fristad Inge , Wimalawansa Sunil J. , Kvinnsland Inger Hals
Published: November 2003

There is little evidence that neuropeptides such as substance P (SP) and calcitonin gene‐related peptide (CGRP) participate in the regulation of tooth development. The aim of this study was to analyse the expression of their respective receptors, neurokinin (NK) 1 and CGRP1 receptor, in postnatal developing rat molars and supporting tissues, thereby localizing the target areas for neuropeptide activity. Mol:WIST rats were killed at 7, 14 and 21 d after birth and upper and lower jaws were processed for immunohistochemistry. At early crown stage (P7), only a few individual cells in the dental follicle were receptor positive. At the onset of root formation (P14), post‐secretory ameloblasts, cells in the stratum intermedium, the reduced enamel epithelium and the developing alveolar bone demonstrated both NK1 and CGRP1 receptor immunoreactivity. The CGRP1 receptor sites were occasionally evident on cells in the odontoblast layer. At advanced root development (P21), neuropeptide receptor expression was evident on cells close to the developing dentin, cementum and alveolar bone. These data demonstrate dynamic changes in the localization of NK1 and CGRP1 receptors in developing rat dental tissues and indicate an active role for their ligands in the regulation of crown and root development.
Inverse regulation of the ADAM‐family members, decysin and MADDAM/ADAM19 during monocyte differentiation
Authors: Fritsche Jana , Müller Alexandra , Hausmann Martin , Rogler Gerhard , Andreesen Reinhard , Kreutz Marina
Published: November 2003

Two members of the ADAM (a disintegrin and metalloprotease)‐family, MADDAM and decysin, were described as dendritic cell (DC) maturation markers. We are interested in monocyte differentiation and investigated in particular the expression pattern of both genes during the differentiation of human monocytes into DC and macrophages (MAC). Both genes are weakly expressed in freshly isolated monocytes. In immature DC decysin mRNA was absent, even after induction of the terminal differentiation of DC by CD40L or tumour necrosis factor‐α (TNF‐α). Only in DC maturated by lipopolysaccharide (LPS) strong signals of decysin mRNA were detected. However, MADDAM mRNA was expressed in immature DC and the expression was markedly increased after induction of the terminal DC differentiation by various stimuli. In contrast, MAC showed a high constitutive decysin mRNA expression, but expressed no MADDAM mRNA. On protein level similar results of MADDAM expression were obtained. Stimulation of MAC by LPS did not induce MADDAM mRNA expression, while decysin mRNA expression was strongly increased. Further investigations revealed that the well‐known inducer of MAC differentiation, 1α,25‐dihydroxyvitamin D3 up‐regulated decysin mRNA expression during the differentiation of primary monocytes and myelomonocytic THP‐1 cells into MAC. In vivo decysin mRNA expression was only detected in human colon, but not in other tissues we examined. Accordingly, isolated intestinal MAC expressed decysin mRNA. In conclusion, decysin and MADDAM mRNA expression were regulated in an opposite way during monocyte differentiation: MADDAM mRNA and protein was mainly detected in DC, whereas decysin mRNA expression was mainly found in MAC. Therefore only MADDAM, but not decysin is a suitable marker for human monocyte‐derived DC.
Porcine peripheral blood dendritic cells and natural interferon‐producing cells
Authors: Summerfield Artur , Guzylack‐Piriou Laurence , Schaub Alexander , Carrasco Carlos P. , Tâche Valerie , Charley Bernard , McCullough Kenneth C.
Published: November 2003

Peripheral blood contains two major particular infrequent dendritic cells (DC) subsets linking the innate and specific immune system, the myeloid DC and plasmacytoid DC equivalent to the natural interferon‐producing cells (NIPC). The functional characterization of these cells demands large volumes of blood, making a large animal model more appropriate and beneficial for certain studies. Here, two subsets of porcine blood mononuclear cells expressing swine workshop cluster 3 (SWC3, a SIRP family member), are described and compared to monocytes. The blood DC specialized in T‐cell stimulation were major histocompatibility complex (MHC) class II+, CD80/86+, CD1+/–, CD4−, and in contrast to monocytes CD14−. A CD16− and a CD16+ subset could be discriminated. Granulocyte–macrophage colony‐stimulating factor and interleukin‐3 were survival factors for this DC subset, and culture induced an up‐regulation of MHC class II and CD80/86. The second subset described, are porcine NIPC, typically CD4++, MHC class IIlow, CD80/86low, CD1−, CD8−/low, CD16−/low and CD45RA−/low. Porcine NIPC had high interleukin‐3 binding capacity, and survived in response to this cytokine. Their unique function was strong interferon type I secretion after virus stimulation. Both subsets were endocytically active when freshly isolated, and down‐regulated this activity after in vitro maturation. Taken together, the present report has delineated porcine blood DC and NIPC, permitting a more detailed understanding of innate immune defences, particularly in response to infections.
B‐cell antigen‐receptor signalling in lymphocyte development
Authors: Wang Leo D. , Clark Marcus R.
Published: November 2003

Signalling through the B‐cell antigen receptor (BCR) is required throughout B‐cell development and peripheral maturation. Targeted disruption of BCR components or downstream effectors indicates that specific signalling mechanisms are preferentially required for central B‐cell development, peripheral maturation and repertoire selection. Additionally, the avidity and the context in which antigen is encountered determine both cell fate and differentiation in the periphery. Although the signalling and receptor components required at each stage have been largely elucidated, the molecular mechanisms through which specific signalling are evoked at each stage are still obscure. In particular, it is not known how the pre‐BCR initiates the signals required for normal development or how immature B cells regulate the signalling pathways that determine cell fate. In this review, we will summarize the recent studies that have defined the molecules required for B‐cell development and maturation as well as the theories on how signals may be regulated at each stage.
Parental allergic status influences the risk of developing allergic sensitization and an asthmatic‐like phenotype in canine offspring
Authors: Barrett Edward G. , Rudolph Karin , Bowen Larry E. , Bice David E.
Published: November 2003

Increasing evidence suggests that parental allergic status, especially that of the mother, may play a unique and important role in influencing the development of fetal infant immune responses to inhaled allergens, independently of genetic predisposition. We have developed an experimental model in dogs where the offspring from allergic parents, when exposed to inhaled allergen, develop allergic sensitization and an asthmatic phenotype, whereas the offspring from non‐allergic parents do not. Offspring from ragweed‐sensitized (two litters, n = 10) or non‐sensitized (two litters, n = 11) Beagle dogs were exposed repeatedly, by inhalation, to ragweed or filtered air (negative control) beginning within 1 week after birth. Serum levels of total immunoglobulin (Ig)E, and ragweed‐specific IgE and IgG, were measured at specific time‐points up to 40 weeks after birth. Cell differentials in the bronchoalveolar lavage were determined on days 1 and 4 following ragweed instillation into the offspring's lungs at 26 weeks of age. Changes in pulmonary resistance following challenge with histamine and ragweed (five breaths) were measured at 40 weeks after birth. Offspring from sensitized parents exposed to ragweed developed elevated serum total IgE and ragweed‐specific IgE and IgG, and showed an increased pulmonary resistance to histamine and ragweed, and increased numbers of eosinophils in bronchoalveolar lavage. In contrast, offspring from non‐sensitized parents did not exhibit this immune response. These results suggest that parental allergic sensitivity is important in the development of allergic sensitization and an asthmatic phenotype in the offspring.
DEC‐205lo Langerinlo neonatal Langerhans' cells preferentially utilize a wortmannin‐sensitive, fluid‐phase pathway to internalize exogenous antigen
Authors: Bellette Bernadette M. , Woods Gregory M. , Wozniak Teresa , Doherty Kathleen V. , Muller H. Konrad
Published: November 2003

Antigen treatment of neonatal epidermis results in antigen‐specific immune suppression. Compared with adult counterparts, neonatal Langerhans' cells (LC) demonstrate an impaired ability to transport antigen to the lymph node (LN). As it is possible that neonatal LC have a reduced ability to endocytose antigen, we evaluated the acquisition of endocytic function, the expression of uptake receptors and the internalization of soluble and small particulate antigens in neonatal, juvenile and adult mice. Although LC from 4‐day‐old mice were weakly positive for the mannose‐type receptor, Langerin, they were capable of internalizing fluorescein isothiocyanate (FITC)‐dextran, but to a lesser extent than LC from 6‐week‐old mice. However, when ratio data were calculated to account for variations in fluorescence intensity at 4°, it was demonstrated that neonatal LC continued to internalize antigen over a longer period of time than adult mice and, as the ratios were much higher, that neonatal cells were also relatively more efficient in antigen uptake. When receptors for mannan and mannose were competitively blocked, LC from neonatal mice, but not adult mice, could still efficiently internalize FITC–dextran. Consequently, the uptake of FITC–dextran, in part, occurred via alternative receptors or a receptor‐independent fluid‐phase pathway. A feasible pathway is macropinocytosis, as LC from 4‐day‐old mice demonstrated a reduction in FITC–dextran internalization by the macropinocytosis inhibitor, wortmannin. Evidence of a functional macropinocytosis pathway in neonatal LC was further supported by internalization of the soluble tracer Lucifer Yellow (LY). We conclude that neonatal LC preferentially utilize a wortmannin‐sensitive, fluid‐phase pathway, rather than receptor‐mediated endocytosis, to internalize antigen. As neonatal LC are capable of sampling their environment without inducing immunity, this may serve to avoid inappropriate immune responses during the neonatal period.
Up‐regulation of granulomatous inflammation in interleukin‐6 knockout mice infected with Rhodococcus aurantiacus
Authors:   Yimin, Kohanawa Masashi , Minagawa Tomonori
Published: November 2003

After intravenous injection of Rhodococcus aurantiacus normal mice develop non‐necrotic granulomas, the formation of which is dependent on endogenous interferon‐γ (IFN‐γ). In the early phase of R. aurantiacus infection a high level of endogenous interleukin‐6 (IL‐6) is detected in the spleen extracts, though its importance is unknown. Using IL‐6 knockout (IL‐6−/−) mice, we studied the role of IL‐6 in granulomatous inflammation induced by R. aurantiacus. The size of granulomas generated in IL‐6−/− mice was significantly larger than that of wild‐type (IL‐6+/+) mice at 2 weeks postinjection (p.i). Moreover, central necrosis of the granuloma was observed in IL‐6−/− mice but not in IL‐6+/+ controls. Titres of endogenous IFN‐γ and tumour necrosis factor‐α (TNF‐α) were markedly increased in the spleens and livers of IL‐6−/− mice in comparison with IL‐6+/+ mice at days 1 through 3 p.i. In vivo administration of either an anti‐IFN‐γ monoclonal antibody (mAb) or anti‐TNF‐α mAb to IL‐6−/− mice reduced the number and size of granulomas, and prevented formation of necrotic granulomas. In addition, the production of endogenous IFN‐γ and TNF‐α in the early phase of R. aurantiacus infection by IL‐6−/− mice was suppressed by treatment with recombinant IL‐6 (rIL‐6). This suppression of IFN‐γ and TNF‐α production was followed by a reduction in the number and size of central necrotic granulomas at 2 weeks p.i. These findings suggest that overproduction of IFN‐γ and TNF‐α induces central necrotic granuloma formation in IL‐6−/− mice, and that IL‐6 down‐regulates granulomatous inflammation reaction in response to R. aurantiacus infection by modulating production of IFN‐γ and TNF‐α.
HCV‐specific CD27− CD28− memory T cells are depleted in hepatitis C virus and Schistosoma mansoni co‐infection
Authors: Elrefaei Mohamed , El‐sheikh Nabila , Kamal Karim , Cao Huyen
Published: November 2003

Factors that influence the generation and maintenance of memory CD8+ T cells are not fully understood. The homeostasis of memory T cells is highly dynamic and tightly regulated by various stimuli, including cytokines and antigen–major histocompatibility complex ligands. We characterized the hepatitis C virus (HCV)‐specific CD8+ T‐cell responses in a cohort of HCV‐infected individuals with or without Schistosoma mansoni co‐infection from Egypt. We observed a significantly decreased CD27− CD28− (late differentiated) memory T‐cell population in the HCV co‐infected individuals compared to those with HCV infection alone. In contrast, there was no significant difference in the CD27+ CD28+ (early differentiated) memory T cells between the two groups. Analysis of human cytomegalovirus‐specific CD8+ T‐cell responses in the same individuals failed to reveal a similar pattern of altered memory T‐cell differentiation. Thus, S. mansoni co‐infection targets a specific subset of memory CD8+ T cells in HCV infection.