bluuebunny/crossref_metadata_2025 huggingface dataset:
Interventionen und deren Effekte auf pflegende Angehörige von Menschen mit Demenz – Eine systematische Literaturübersicht
Authors: Mantovan Franco , Ausserhofer Dietmar , Huber Markus , Schulc Eva , Them Christa
Published: August 2010

Durch die häusliche Pflegesituation sind pflegende Angehörige von Menschen mit Demenz einer Vielzahl an physischen, psychischen und sozialen Belastungen bzw. Einschränkungen ausgesetzt und laufen Gefahr, selbst zu erkranken. Pflegende Angehörige benötigen adäquate Entlastungsangebote, um die Pflege ihres Familienmitglieds zuhause so lange und so gesund wie möglich durchführen zu können. In der vorliegenden Arbeit wurden anhand einer systematischen Literaturübersicht Entlastungs- und Förderinterventionen und deren Effekte auf pflegende Angehörige von Demenzerkrankten recherchiert und dargestellt. Aus der Ergebnisdarstellung geht hervor, dass psychoedukative, pflegeentlastende, unterstützende, psychotherapeutische und multimodale Angebote sowie Case und Care Management bei pflegenden Angehörigen signifikante Effekte auf Ergebnisparameter wie Belastungen, Depressivität, subjektives Wohlbefinden, Fähigkeiten/Wissen sowie Symptome und Institutionalisierung des Pflegebedürftigen zeigen. Keine der untersuchten Interventionen deckt jedoch alle Ergebnisparameter ab. Um eine individuelle Versorgung pflegender Angehöriger sicherstellen zu können, bedarf es eines übergeordneten organisatorischen Konzepts (z. B. Case/Care Management, Family Health Nursing) das die Bedürfnisse der pflegenden Angehörigen erkennt, bedarfsgerechte Angebote für pflegende Angehöriger kombiniert und vernetzt. Diplomierte Gesundheits- und Krankenpflegepersonen könnten als «Care Manager» oder «Family Health Nurses» bei der Sicherstellung der häuslichen Pflege von Menschen mit Demenz eine zentrale Rolle spielen. Weitere Untersuchungen zu multimodalen Angeboten bzw. Case bzw. Care Management werden benötigt, wobei eine sorgfältige Wahl des Studiendesigns, der Stichprobengröße und der Ergebnisparameter (Assessmentinstrumente) getroffen werden muss, um signifikante Ergebnisse und homogene Daten zu produzieren.
«Wer ist Glossar?» – Fokusgruppen-Evaluation einer evidenzbasierten Verbraucherinformation zu Sturzgefährdung und -vorbeugung im Alter
Authors: Schmitz Astrid , Lins Sabine , Krüger Cäcilia , Segmüller Tanja , Adler Kai , Meyer Gabriele
Published: August 2010

Evidenzbasierte Patienten- und Verbraucherinformation (EBPI) möchte durch objektive und sachliche Darstellung der wissenschaftlichen Beweislage zu einem spezifischen Gesundheitsproblem den Bürgern zu einer informierten Entscheidung verhelfen. Zum Thema Sturzvorbeugung liegen bereits einige Informations­materialien vor. Bislang gibt es jedoch keine Verbraucherinformation, die gemäß der Kriterien einer EBPI gestaltet ist. Wie eine solche Information von älteren Personen angenommen wird, ist unklar. In drei Fokusgruppen-Interviews mit insgesamt 19 Senioren wurde eine kürzlich entwickelte EBPI zum Thema Sturzgefährdung und -vorbeugung im Alter auf Verständlichkeit und Akzeptanz evaluiert. Für die meisten Teilnehmer blieb das Ziel der EBPI unklar, obgleich es explizit formuliert war. Die Teilnehmer hatten mehrheitlich konkrete Handlungsanweisungen zur Sturzvorbeugung erwartet. Die numerischen und grafischen Darstellungen zu Risikofaktoren, Sturz- und Bruchhäufigkeit und Therapieeffekten wurden überwiegend als ungewohnt und verwirrend eingestuft. Neben emotionalen Reaktionen, Abwertung und selektiver Wahrnehmung von Informationsanteilen durch einige Teilnehmer gab es auch positive Resonanz bezüglich der sachlichen und nicht indoktrinierenden Art der Darstellung. Die Untersuchung bestätigt Akzeptanzprobleme für EBPI, die mehrheitlich auf nicht erfüllte Erwartungshaltung und mangelnde Gewohnheit im Umgang mit dieser Art des Informationsangebotes zurückzuführen sein dürfte.
Metabolic Acidosis Induced by Plasmodium Falciparum Intraerythrocytic Stages Alters Blood—Brain Barrier Integrity
Authors: Zougbédé Sergine , Miller Florence , Ravassard Philippe , Rebollo Angelita , Cicéron Liliane , Couraud Pierre-Olivier , Mazier Dominique , Moreno Alicia
Published: August 2010

The pathogenesis of cerebral malaria (CM) remains largely unknown. There is growing evidence that combination of both parasite and host factors could be involved in blood–brain barrier (BBB) breakdown. However, lack of adequate in vitro model of human BBB so far hampered molecular studies. In this article, we propose the use of hCMEC/D3 cells, a well-established human cerebral microvascular endothelial cell (EC) line, to study BBB breakdown induced by Plasmodium falciparum-parasitized red blood cells and environmental conditions. We show that coculture of parasitized erythrocytes with hCMEC/D3 cells induces cell adhesion and paracellular permeability increase, which correlates with disorganization of zonula occludens protein 1 expression pattern. Permeability increase and modification of tight junction proteins distribution are cytoadhesion independent. Finally, we show that permeability of hCMEC/D3 cell monolayers is mediated through parasite induced metabolic acidosis, which in turns correlates with apoptosis of parasitized erythrocytes. This new coculture model represents a very useful tool, which will improve the knowledge of BBB breakdown and the development of adjuvant therapies, together with antiparasitic drugs.
Integrin structure: new twists and turns in dynamic cell adhesion
Authors: Arnaout M. Amin
Published: August 2010

Summary: The divalent‐cation‐dependent binding of αβ heterodimeric integrins to their ligands regulates most cellular processes. Integrin–ligand interactions are tightly controlled by inside‐out activation signals. Ligand‐bound integrins transduce outside‐in signals typical of other receptors. Precise information of how ligands bind to integrins is restricted to that of a small vWF A‐type domain present in some α‐subunits (αA). Both inside‐out and outside‐in signals elicit tertiary and quaternary changes in integrins, but the precise nature and scope and of these changes are unknown. The recently solved structures of the extracellular segment of integrin αVβ3 in its unliganded and liganded states are generating exciting new insights into the design, wiring, function and regulation of this protein family. The structures reveal a surprising degree of flexibility at defined regions in the structure that is potentially controlled by cations. The quaternary structure of the ligand‐binding region bears a striking resemblance to the nucleotide‐binding pocket of G‐proteins, implying analogous signaling mechanisms. Structural links exist through which ligand‐induced tertiary changes may be translated into quaternary changes and vice versa. The structures also raise the tantalizing hypothesis that αA is a regulated endogenous integrin ligand, so that no special regulatory features are needed in this integrin. These findings provide the framework for new investigations of structure–activity relationships in integrins, with important implications for targeting these receptors therapeutically.
The influence of body mass index on skin susceptibility to sodium lauryl sulphate
Authors: Löffler H. , Aramaki J. U. N. , Effendy Isaak
Published: August 2010

Background:  The influence of nutrition on the physiological functions of man is well studied. Numerous diseases can be exacerbated by obesity. However, it has not yet been determined whether body weight and body mass index (BMI), as an indicator of a high body fat store, can influence skin sensitivity.

Objective:  This study investigates the correlation between body mass index and the epidermal functions, evaluated by bioengineering methods, before and after an irritant patch test with sodium lauryl sulphate (SLS).

Methods:  Epidermal functions were evaluated using an evaporimeter, chromameter and laser‐Doppler‐flowmeter. Patch testing was conducted for 48 h with two different concentrations of SLS (0.25% and 0.5%) on the forearms of healthy volunteers. Measurements were performed 24 h after patch removal.

Results:  Obese individuals showed significantly increased transepidermal water loss (TEWL), skin blood flow and skin colour (red) as compared to a control group. However, the degree of skin sensitivity to SLS was not correlated with BMI.

Conclusion:  Basal biophysical parameters of the skin are primarily correlated with the BMI. This may be caused by obesity‐induced physiological changes, e.g. increased sweat gland activity, high blood pressure and physiological temperature‐regulating system. The epidermal barrier function, as evaluated after SLS patch testing is, however, not correlated with a high BMI, indicating a normal skin barrier.
Multiple coherent states semiclassical initial value representation spectra calculations of lateral interactions for CO on Cu(100)
Authors: Ceotto Michele , Dell’Angelo David , Tantardini Gian Franco
Published: August 2010

Lateral interactions between carbon monoxide molecules adsorbed on a copper Cu(100) surface are investigated via semiclassical initial value representation (SC-IVR) molecular dynamics. A previous analytical potential is extended to include long-range dipole interactions between coadsorbed molecules and preliminary classical simulations were performed to tune the potential parameters. Then, the spectra for several coadsorbed molecules are calculated using the multiple coherent states approximation of the time-averaging representation of the SC-IVR propagator. Results show strong resonances between coadsorbed molecules as observed by past experiments. Resonances turn into dephasing when isotopical substitutions are performed.
H
2
production from reactions between water and small molybdenum suboxide cluster anions
Authors: Rothgeb David W. , Mann Jennifer E. , Jarrold Caroline Chick
Published: August 2010

Reactions between molybdenum suboxide cluster anions, MoxOy− (x=1–4;y≤3x), and water (H2O and D2O) have been studied using mass spectrometric analysis of products formed in a high-pressure, fast-flow reactor. Product distributions vary with the number of metal atoms in the cluster. Within the MoOy− oxide series, product masses correspond to the addition of one water molecule, as well as a H/D exchange with MoO4H−. Within the Mo2Oy− oxide series, product evolution and distribution suggest sequential oxidation via Mo2Oy−+H2O/D2O→Mo2Oy+1−+H2/D2 reactions for y<5, while for Mo2O5−, Mo2O6H2/D2− is produced. Mo2O6− does not appear to be reactive toward water. For the Mo3Oy− oxide series, sequential oxidation similarly is suggested for y<5, while Mo3O5− reactions result in Mo3O6H2/D2− formation. Mo3O6− appears uniquely unreactive. Mo3O7− and Mo3O8− react to form Mo3O8H2/D2− and Mo3O9H2/D2−, respectively. Lower mass resolution in the Mo4Oy− mass range prevents unambiguous mass analysis, but intensity changes in the mass spectra do suggest that sequential oxidation with H2/D2 evolution occurs for y<6, while Mo4Oy+1H2/D2− addition products are formed in Mo4O6− and Mo4O7− reactions with water. The relative rate constants for sequential oxidation and H2O/D2O addition for the x=2 series were determined. There is no evidence of a kinetic isotope effect when comparing reaction rates of H2O with D2O, suggesting that the H2 and D2 losses from the lower-oxide/hydroxide intermediates are very fast relative to initial reaction complex formation with H2O or D2O. The rate constants determined here are two times higher than those determined in identical reactions between W2Oy−+H2O/D2O.
Reversibility and irreversibility of magnetocaloric effect in a metamagnetic shape memory alloy under cyclic action of a magnetic field
Authors: Khovaylo V. V. , Skokov K. P. , Gutfleisch O. , Miki H. , Kainuma R. , Kanomata T.
Published: August 2010

We have studied adiabatic temperature change ΔTad in a Ni50Mn36Co1Sn13 metamagnetic shape memory alloy. An irreversible character of ΔTad has been observed in the vicinity of the reverse martensitic transformation. In this region, cyclic application of the magnetic field converts comparatively large inverse magnetocaloric effect (MCE) with ΔTadmax=−0.8 K to a weaker conventional MCE (ΔTadmax=0.3 K). The crossover of ΔTad has been attributed to the irreversible character of the magnetic field-induced transformation and the closeness of the martensitic transformation and Curie temperature of the austenitic phase TCA.
MTM1
mutation associated with X-linked myotubular myopathy in Labrador Retrievers
Authors: Beggs Alan H. , Böhm Johann , Snead Elizabeth , Kozlowski Marek , Maurer Marie , Minor Katie , Childers Martin K. , Taylor Susan M. , Hitte Christophe , Mickelson James R. , Guo Ling T. , Mizisin Andrew P. , Buj-Bello Anna , Tiret Laurent , Laporte Jocelyn , Shelton G. Diane
Published: August 2010

Mutations in the
MTM1
gene encoding myotubularin cause X-linked myotubular myopathy (XLMTM), a well-defined subtype of human centronuclear myopathy. Seven male Labrador Retrievers, age 14–26 wk, were clinically evaluated for generalized weakness and muscle atrophy. Muscle biopsies showed variability in fiber size, centrally placed nuclei resembling fetal myotubes, and subsarcolemmal ringed and central dense areas highlighted with mitochondrial specific reactions. Ultrastructural studies confirmed the centrally located nuclei, abnormal perinuclear structure, and mitochondrial accumulations. Wild-type triads were infrequent, with most exhibiting an abnormal orientation of T tubules.
MTM1
gene sequencing revealed a unique exon 7 variant in all seven affected males, causing a nonconservative missense change, p.N155K, which haplotype data suggest derives from a recent founder in the local population. Analysis of a worldwide panel of 237 unaffected Labrador Retrievers and 59 additional control dogs from 25 other breeds failed to identify this variant, supporting it as the pathogenic mutation. Myotubularin protein levels and localization were abnormal in muscles from affected dogs, and expression of GFP-MTM1 p.N155K in COS-1 cells showed that the mutant protein was sequestered in proteasomes, where it was presumably misfolded and prematurely degraded. These data demonstrate that XLMTM in Labrador Retrievers is a faithful genetic model of the human condition.
T-type channels control the opioidergic descending analgesia at the low threshold-spiking GABAergic neurons in the periaqueductal gray
Authors: Park Cheongdahm , Kim Jong-Hyun , Yoon Bo-Eun , Choi Eui-Ju , Lee C. Justin , Shin Hee-Sup
Published: August 2010

Endogenous opioids generate analgesic signals in the periaqueductal gray (PAG). However, because cell types in the PAG are difficult to identify, its neuronal mechanism has remained poorly understood. To address this issue, we characterized PAG neurons by their electrical properties using differentially labeled GABAergic and output neurons in the PAG. We found that GABAergic neurons were mostly fast-spiking cells and could be further divided into two distinct classes: with or without low-threshold spikes (LTS) driven by T-type channels. In contrast, the PAG output neurons lacked LTS and showed heterogeneous firing patterns. To reveal the function of the LTS, we examined the mutant mice lacking the α1G T-type channels (α1G
−/−
). The mutant mice lacked LTS in the fast-spiking GABAergic neurons of the PAG and unexpectedly showed impaired opioid-dependent analgesia; a similar phenotype was reproduced in PAG-specific α1G-knockdown mice. Electrophysiological analyses revealed functional expression of μ-opioid receptors in the low threshold-spiking GABAergic neurons. These neurons in the mutant lacking LTS showed markedly enhanced discharge activities, which led to an augmented inhibition of output neurons. Furthermore, the impaired analgesia observed in α1G
−/−
mice was reversed by blocking local GABA
A
receptors. These results indicate that α1G T-type channels are critical for the opioidergic descending analgesia system in the PAG.
Distinct subclasses of medium spiny neurons differentially regulate striatal motor behaviors
Authors: Bateup Helen S. , Santini Emanuela , Shen Weixing , Birnbaum Shari , Valjent Emmanuel , Surmeier D. James , Fisone Gilberto , Nestler Eric J. , Greengard Paul
Published: August 2010

The direct and indirect pathways of the basal ganglia have been proposed to oppositely regulate locomotion and differentially contribute to pathological behaviors. Analysis of the distinct contributions of each pathway to behavior has been a challenge, however, due to the difficulty of selectively investigating the neurons comprising the two pathways using conventional techniques. Here we present two mouse models in which the function of striatonigral or striatopallidal neurons is selectively disrupted due to cell type–specific deletion of the striatal signaling protein dopamine- and cAMP-regulated phosphoprotein
Mr
32kDa (DARPP-32). Using these mice, we found that the loss of DARPP-32 in striatonigral neurons decreased basal and cocaine-induced locomotion and abolished dyskinetic behaviors in response to the Parkinson's disease drug L-DOPA. Conversely, the loss of DARPP-32 in striatopallidal neurons produced a robust increase in locomotor activity and a strongly reduced cataleptic response to the antipsychotic drug haloperidol. These findings provide insight into the selective contributions of the direct and indirect pathways to striatal motor behaviors.
Risk Assessment: The Value of Structured Professional Judgments
Authors: Pedersen Liselotte , Rasmussen Kirsten , Elsass Peter
Published: August 2010

International research suggests that using formalized risk assessment methods may improve the predictive validity of professionals’ predictions of risk of future violence. This study presents data on forensic psychiatric patients discharged from a forensic unit in Denmark in year 2001–2002 ( n =107). All patients were assessed for risk of future violence utilizing a structured professional judgment model: the HCR-20 violence risk assessment scheme. After a follow-up period of 5.6 years, recidivism outcome were obtained from the Danish National Crime Register. Overall, the predictive validity of the HCR-20 was good. The structured final risk judgment had the highest predictive accuracy of violent recidivism and was superior to the HCR-20 used in an actuarial manner. At the individual item level, a higher number of the dynamic items were significantly predictive of violent recidivism compared to static items. In sum, the findings support the use of structured professional judgment models of risk assessment and in particular the HCR-20 violence risk assessment scheme. Findings regarding the importance of the (clinical) structured final risk judgment and the individual dynamic items strengthen the use of this scheme in clinical practice.
Tuning the localized surface plasmon resonance of silver nanoplatelet colloids
Authors: Singh Asha , Jayabalan J , Chari Rama , Srivastava Himanshu , Oak S M
Published: August 2010

The effect of femtosecond laser irradiation on silver nanoplatelet colloids is described. It is shown that irradiation with a femtosecond laser of appropriate fluence can be used to tune the localized surface plasmon resonances of triangular silver nanoplatelets by a few tens of nanometres. This peak shift is shown to be caused by the structural modifications of the particle tips. We have also shown that post-preparation addition of poly-vinyl pyrrolidone to the nanocolloid arrests the peak shift.
A novel determination of the local dark matter density
Authors: Riccardo Catena  , Piero Ullio
Published: August 2010

We present a novel study on the problem of constructing mass
models for the Milky Way, concentrating on features regarding the
dark matter halo component. We have considered a variegated sample
of dynamical observables for the Galaxy, including several results
which have appeared recently, and studied a 7- or 8-dimensional
parameter space - defining the Galaxy model - by implementing a
Bayesian approach to the parameter estimation based on a Markov
Chain Monte Carlo method. The main result of this analysis is a
novel determination of the local dark matter halo density which,
assuming spherical symmetry and either an Einasto or an NFW density
profile is found to be around 0.39 GeV cm−3 with a 1-σ
error bar of about 7%; more precisely we find a ρ
DM
(R
0) = 0.385±0.027 GeV cm−3 for the Einasto profile and
ρ
DM
(R
0) = 0.389±0.025 GeV cm−3 for the
NFW. This is in contrast to the standard assumption that
ρ
DM
(R
0) is about 0.3 GeV cm−3 with an uncertainty of a
factor of 2 to 3. A very precise determination of the local halo
density is very important for interpreting direct dark matter
detection experiments. Indeed the results we produced, together with
the recent accurate determination of the local circular velocity,
should be very useful to considerably narrow astrophysical
uncertainties on direct dark matter detection.
Engineered spin chains for perfect quantum state transfer
Authors: Nguyen Bich Ha , Nguyen Van Hieu
Published: August 2010

The transfer of quantum states along spin chains with the XY Heisenberg exchange interaction between nearest-neighbour spins and without decoherence was studied. It was shown that there exists a wide class of engineered mirror-symmetric N-spin-chains that allow the perfect quantum state transfer from one end of each chain to the other. The sets of values of physical parameters of these N-spin-chains were established.
Synthesis, capping and binding of colloidal gold nanoparticles to proteins
Authors: Nghiem Thi Ha Lien , La Thi Huyen , Vu Xuan Hoa , Chu Viet Ha , Nguyen Thanh Hai , Le Quang Huan , Fort Emmanuel , Do Quang Hoa , Tran Hong Nhung
Published: August 2010

Bovine serum albumin (BSA) was used as a stabilizing agent and biofunctionalized layer for water-dispersed gold nanoparticles (NPs) synthesized from metal precursor HAuCl
4. The BSA binding to gold NPs was characterized qualitatively and quantitatively by transmission electron microscopy, UV-VIS and FTIR spectrophotometers. HER2 (human epidermal growth factor receptor 2) specific phage antibodies were attached to BSA stabilized gold NPs to form a gold–antibody complex. An ELISA (enzyme-linked immunosorbent assay) test was done to confirm the bioactivity of antibodies attached to gold NPs.
Oxidation of a platinum microwire surface applied in glucose detection
Authors: Pham Xuan Thanh Tung , Tuyen Le Thi Thanh , Duy Tran Phu , Van Pham Binh , Hien Tong Duy , Chien Dang Mau
Published: August 2010

In this paper, we report the results of the surface oxidation of platinum (Pt) microwires in aqueous sulfuric acid (H
2
SO
4) solutions by using a cyclic voltammetry technique. The Pt microwire chips were scanned and applied with voltage potentials ranging from 0 to 1.4 V in the H
2
SO
4 solution with concentrations from 0.0003 to 0.0018 M to find out the optimized concentration of sulfuric acid for the oxidation process. The cyclic voltammetry (CV) measurements show the oxidation peak at a potential range from 1.1 to 1.2 V. This is the peak of the interfacial place exchange of chemisorbed O (O

chem
) and surface Pt atoms, resulting in the formation of a quasi-3D surface PtO lattice comprising Pt
2+ and O
2−. The oxidized surface Pt microwires were then functionalized with a 3-aminopropyl triethoxy silane (APTES) and glucose oxidase (GOD) was immobilized onto the functionalized chips for further application in glucose detection. By using this process, Pt microwires have been used for the successful detection of glucose in solution with concentrations in the range of 4–20 mM.
Framework of stock-recovery strategies: analyses of factors affecting success and failure
Authors: Hammer Cornelius , von Dorrien Christian , Hopkins Christopher C. E. , Köster Fritz W. , Nilssen Einar M. , St John Michael , Wilson Douglas C.
Published: August 2010

Hammer, C., von Dorrien, C., Hopkins, C. C. E., Köster, F. W., Nilssen, E. M., St John, M., and Wilson, D. C. 2010. Framework of stock-recovery strategies: analyses of factors affecting success and failure. – ICES Journal of Marine Science, 67: 1849–1855. The EU FP6 UNCOVER project was aimed at producing a rational scientific basis for developing recovery strategies for some ecologically and socio-economically important fish stocks/fisheries in European seas. The immediate objectives were to identify changes experienced during stock depletion/collapses, to understand prospects for recovery, to enhance the scientific understanding of the mechanisms of recovery, and to formulate recommendations on how best to implement long-term management/recovery plans. We extended an earlier analysis conducted within the project of 13 performance criteria in relation to the recovery of more than 30 fish stocks/fisheries worldwide by multivariate exploratory analysis (canonical correspondence analysis), followed by model building [discriminant analysis (DA)] to quantify the relative importance of key performance criteria, singly or combined. Using the existing database, DA indicated that the four best additive predictors of successful recovery were “rapid reduction in fishing mortality”, “environmental conditions during the recovery period”, “life-history characteristics” of the target stock, and “management performance criteria”. The model classified the status “recovered” and “non-recovered” assigned originally with nearly 100% accuracy.
The effects of triphenyltin chloride on respiration and photosynthesis in the green algae Enteromorpha intestinalis and Ulothrix pseudoflacca
Authors: MILLNER P. A. , EVANS L. V.
Published: August 2010

Abstract Respiration and photosynthesis in zoospores of Enteromorpha intestinalis (L.) Link and Ulothrix pseudoflacca Wille showed greater sensitivity to inhibition by triphenyltin chloride than in vegetative tissue. Photosynthesis in zoospores and vegetative tissue of U. pseudoflacca was more resistant to triphenyltin chloride inhibition than in zoospores and vegetative tissue of E. intestinalis. Respiration in zoospores and vegetative tissue of both species was equally sensitive to triphenyltin chloride.
Fusicoccin effects on maize roots: relationship between malate accumulation and elongation
Authors: GABELLA M. , PILET P. E.
Published: August 2010

Abstract In maize root segments malate accumulation, measured by gas chromatography, was found to be strongly promoted by fusicoccin (FC). The effects of FC on root elongation and proton extrusion were also analysed. Growth rates and extrusion rates were found to be proportional to malate content. Other organic acids were analysed, but no significant changes were found following FC treatment. The effects of FC are discussed in relation to the regulation of metabolism and growth.
Photomorphogenesis and phyllotaxis during vegetative growth in Sinapis alba and Xanthium strumarium
Authors: BARSCH‐GOLLNAU S. , RITTERBUSCH A. , MOHR H.
Published: August 2010

Abstract The effect of light on the rate of formation of leaf primordia was investigated at the apex of seedlings of Sinapis alba and Xanthium strumarium. It was found that light accelerates this rate. On the other hand, no significant light effect was found on the angles of divergence of successive leaves during the transition from the almost decussate leaf position of the cotyledons to the helical phyllotaxis of the stem leaves. In fact, light and dark grown plants use the same leaves for the transition from decussate to helical phyllotaxis. Thus, if time is plotted in ‘biological units’ (number of primordia) there is no difference between light and dark grown plants. Using scanning electron microscope techniques it was found that the ‘primordia free apical area’ enlarges during development. The rate of enlargement is accelerated by light. However, if time is expressed in biological units (number of primordia) no difference between light and dark grown plants exists. It is concluded that light accelerates the realization of the apical pattern without interfering with the specification of the pattern. In other words, light accelerates the development of an apex without affecting the temporal and spatial coordination of the events.
A re‐examination of the induction of phloem transfer cell development in pea leaves (Pisum sativum)
Authors: HENRY YVONNE , STEER MARTIN W.
Published: August 2010

Abstract The development of phloem transfer cells in expanded dark grown leaflets of pea seedlings (Pisum sativum) has been re‐examined. In agreement with previous observations transfer cells in leaflets maintained in the dark did not form wall ingrowths to the same extent as those placed in the light. A previous report that exposure to light in a carbon dioxide depleted atmosphere inhibited wall ingrowth formation could not be confirmed. It was found that dark grown leaflets could be induced to form wall ingrowths without illumination by immersing them in a glucose solution, demonstrating for the first time that light is not necessary for phloem transfer cell differentiation in leaves.

Attempts were made to alter the carbohydrate level in the whole seedling by removing the cotyledons, but this had no recognizable effect on wall ingrowth formation in any of the treatments. Starch grain formation in the plastids was taken as an indication of available soluble carbohydrate level in the leaflets. It is concluded that both light and the presence of soluble carbohydrate can independently induce wall ingrowth formation in phloem transfer cells of pea leaflets.
The adaptive significance of amphistomatic leaves
Authors: MOTT KEITH A. , GIBSON ARTHUR C. , O'LEARY JAMES W.
Published: August 2010

Abstract A clear correlation between the presence of stomata on both surfaces and factors such as habitat, growth form, and physiology has yet to emerge in the literature. However, certain loose trends with these factors are evident, and these are reviewed along with evidence for hypostomaty as the primitive form. It is proposed that the effect of developing stomata on the upper surface as well as the lower is to increase maximum leaf conductance to CO2. Plants with a high photosynthetic capacity, living in full‐sun environments, and experiencing rapidly fluctuating or continuously available soil water (as opposed to seasonal or long‐term soil water depletion), are identified as deriving an adaptive advantage from a high maximum leaf conductance. The correlation between groups of plants fitting the above conditions and those noted to be amphistomatic is remarkable. Plants not fitting the conditions are found to be largely hypostomatic.
Effects of competitive inhibitors of phenylalanine ammonia‐lyase on the levels of phenylpropanoid enzymes in Solatium tuberosum
Authors: LAMB C. J.
Published: August 2010

Abstract The accumulation of chlorogenic acid in illuminated discs of Solanum tuberosum tuber tissue is accompanied by rapid but transient increases in the activity levels of the biosynthetic enzymes phenylalanine ammonia‐lyase, cinnamic acid 4‐hydroxylase and hydroxycinnamoyl‐CoA : quinate hydroxycinna‐moyl transferase. Exogenous D‐phenylalanine and L‐α‐aminooxy‐β‐phenylpropionic acid, competitive inhibitors of phenylalanine ammonia‐lyase, inhibit the accumulation of chlorogenic acid and presumably reduce the endogenous pools of pathway intermediates such as cinnamic acid. These treatments prolong the phase of increase in phenylalanine ammonia‐lyase and cinnamic acid 4‐hydroxylase activities and indicate that product feedback modulation is important in maintaining the interrelationship between the levels of these two enzymes during the later stages of induction. In contrast,L‐α‐aminooxy‐β‐phenylpropionic acid inhibits the development of hydroxycinnamoyl transferase in illuminated discs supporting the idea that the light‐stimulated increase in phenylalanine ammonia‐lyase activity causes an increase in cinnamic acid production which mediates the light‐stimulated increase in hydroxycinnamoyl transferase activity.
STRUCTURAL ORGANIZATION OF PLASTID DNA IN TWO ANOMALOUSLY PIGMENTED DINOFLAGELLATES1
Authors: Kite Geoffrey C. , Dodge John D.
Published: August 2010

The structural organization of DNA in the plastids of two anomalously pigmented dinoflagellates, Glenodinium foliaceum Stein and Gyrodinium aureolum Hulburt, was determined using the DNA‐specific fluorochrome DAPI and correlated with TEM observations. The plastids of G. foliaceum were found to possess both a peripheral DNA ring and isolated point nucleoids. This arrangement was shown to be similar to that of the diatom Asterionella formosa Hass. and may be characteristic of the Bacillariophyceae. G. aureolum exhibited a novel distribution of plastid. DNA as one or two beaded bands, whereas the plastids of the similarly pigmented haptophyte, Emiliania huxleyi (Lohm.) Hay & Mohler, possessed scattered point nucleoids. These findings support the idea that G. foliaceum harbours an endosymbiotic diatom, but suggest that the plastids of G. aureolum and E. huxleyi are unrelated. The use of plastid DNA configuration as a phylogenetic marker is considered.
NUCLEAR SYNCHRONY IN VALONIA MACROPHYSA(CHLOROPHYTA): LIGHT MICROSCOPY AND FLOW CYTOMETRY1
Authors: Staves Mark P. , La Claire John W.
Published: August 2010

The coenocytic alga Valonia macrophysa Kützing was selected for an investigation of nuclear synchrony in the order Siphonocladales. Light microscopy reveals that nuclear synchrony is evident as patches of nuclei dividing simultaneously. Flow cytometry was utilized for the first time with a macroalga for cell‐cycle analysis. Results indicate that nuclei in the entire cell exhibit a high degree of synchrony throughout the cell cycle. Also it appears that cells within a clonal culture are synchronous with each other, in their progression through the cell cycle. The advantages of using flow cytometry for cell‐cycle analysis of coenocytic algae include the rapid collection of quantitative data on relative DNA content for a large number of nuclei.
ULTRASTRUCTURE OF THE FLAGELLA OF THE COLORLESS PHAGOTROPH PERANEMA TRICHOPHORUM (EUGLENOPHYCEAE). I. FLAGELLAR MASTIGONEMES1
Authors: Hilenski Lula L. , Walne Patricia L.
Published: August 2010

The organization of two types of nontubular mastigonemes associated with the anterior flagellar surface of the phagotrophic biflagellate Peranema trichophorum (Ehrenberg) Stein is described from studies of thin sections, negative‐stained and shadow‐cast preparations of both intact and isolated, detergent‐treated flagella. Long mastigonemes form a unilateral, spiral array of tufts which curve toward the distal end of the flagellum, while two short mastigoneme ribbons form unequal halves of a bilateral array parallel to the flagellar long axis. Each ribbon is composed of individual overlapping fan‐shaped tiers of short mastigonemes interlinked by fine fibrils. A model proposed for Peranema mastigonemes is similar to recent models of mastigoneme organization in Euglena.
INTERACTING EFFECTS OF LIGHT AND NUTRIENT LIMITATION ON THE GROWTH RATE OFSYNECHOCOCCUS LINEARIS(CYANOPHYCEAE)1
Authors: Healey F. Patrick
Published: August 2010

The blue‐green algaSynechococcus linearis(Naeg.) Kom. was grown in P‐ and N‐limited chemostats over a range of potentially limiting irradiances in order to determine the combined effects of light and nutrient limitation on some aspects of the composition and metabolism of this alga. Over a narrow range of low irradiances, simultaneous limitation of growth rate by light and either N or P was shown. This simultaneous limitation of growth rate by a nutrient and a physical factor can be explained by the ability of an increased supply of one to compensate in part for a decreased supply of the other. At all irradiances, the internal concentration of the limiting nutrient increased with increasing dilution rate, and the results could be fitted to the Droop relationship. With decreasing irradiance, the internal concentration of the limiting nutrient increased. There appeared to be little or no effect of light on the minimum internal concentration of P but that of N increased with decreasing light. Both chlorophyllaand biliprotein per unit particulate C increased with increasing dilution rate and decreasing irradiance. The critical N/P ratio increased with decreasing light as the N requirement of N‐limited cells increased faster than did the P requirement of P‐limited cells. The composition of exponentially growing cells in complete medium varied much less with light. Neither dilution rate nor irradiance during growth had a great effect on saturated rates of P or N uptake or alkaline phosphatase activity. Calculated assimilation ratios increased with light and dilution rate. The role of the flexibility of nutrient composition in adaptation to adverse conditions and the implications of the results for the use of physiological indicators of nutrient status are discussed.
SILICON UPTAKE BY ALGAE WITH NO KNOWN Si REQUIREMENT. II. STRONG pH DEPENDENCE OF UPTAKE KINETIC PARAMETERS IN PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1
Authors: Riedel Gerhardt F. , Nelson David M.
Published: August 2010

Silicon uptake kinetics of the diatom Phaeodactylum tricornutum (Bohlin) were examined at pH 8.8 ± 0.1 and pH 9.1 ± 0.1. Uptake follows hyperbolic saturation kinetics at both pH's, but at the higher pH the half‐saturation constant for uptake is 11.8 μM, as opposed to 54.8 μM at the lower pH. When the uptake rate is examined as a function of the calculated concentration of the monovalent conjugate base, SiO(OH)3−, the half‐saturation constant for uptake is 6.6 μM at either pH.
NOSTOC (CYANOPHYTA) PRODUCTIVITY IN OREGON STREAM ECOSYSTEMS: INVERTEBRATE INFLUENCES AND DIFFERENCES BETWEEN MORPHOLOGICAL TYPES1
Authors: Ward Amelia K. , Dahm Clifford N. , Cummins Kenneth W.
Published: August 2010

Nostoc parmelioides colonies housing dipteran larvae (Cricotopus) had higher rates of weight specific photosynthesis than colonies without the larvae. A change in colony shape, which allowed the alga to be exposed to higher light intensities, occurred, in the presence of the larvae. This change in morphology together with potential nutrient additions by the larvae and other effects may have caused the increase in photosynthetic rates. Nostoc colonies were typically found in open areas of small streams in western Oregon mountains where the ability to respond to high light would be advantageous in supporting the metabolically expensive process of nitrogen fixation.
LIGHT AND TEMPERATURE AS FACTORS REGULATING SEASONAL GROWTH AND DISTRIBUTION OF ULOTHRIX ZONATA (ULVOPHYCEAE)1
Authors: Graham James M. , Kranzfelder James A. , Auer Martin T.
Published: August 2010

Ulothrix zonata (Weber and Mohr) Kütz. is an unbranched filamentous green alga found in rocky littoral areas of many northern lakes. Field observations of its seasonal and spatial distribution indicated that it should have a low temperature and a high irradiance optimum for net photosynthesis, and at temperatures above 10°C it should show an increasingly unfavorable energy balance. Measurements of net photosynthesis and respiration were made at 56 combinations of light and temperature. Optimum conditions were 5°C and 1100 μE·m−2·s−1 at which net photosynthesis was 16.8 mg O2·g−1·h−1. As temperature increased above 5° C optimum irradiance decreased to 125 μE·m−2·s−1 at 30°C. Respiration rates increased with both temperature and prior irradiance. Light‐enhanced respiration rates were significantly greater than dark respiration rates following irradiance exposures of 125 μE·m−2·s−1 or greater. Polynomials were fitted to the data to generate response surfaces. Polynomial equations represent statistical models which can accurately predict photosynthesis and respiration for inclusion in ecosystem models.
ANNUAL PRODUCTIVITY AND EXTRACELLULAR RELEASE OF DISSOLVED ORGANIC COMPOUNDS BY THE EPIBENTHIC ALGAL COMMUNITY OF A BRACKISH MARSH1
Authors: Hall Shelly L. , Fisher Frank M.
Published: August 2010

Annual productivity and excretion of organic compounds by epibenthic algae in a coastal Texas marsh were investigated using 14C techniques. Over the course of two years, productivity and extracellular release were measured bimonthly to assess the environmental factors affecting seasonal patterns. Annual productivity was estimated to be 71 gc·m−2, approximately 10% of the estimated net aerial productivity of the grass canopy in this area. The percentage of photoassimilated carbon released was fairly constant, and the rate of excretion appeared to be primarily dependent upon the rate of carbon fixation. Greater rates of release were observed with high salinity, low soil moisture conditions. It was estimated that up to 10% of the DOC in adjacent tidal creek water could be produced by this community and could represent an important source of nutrients for consumers in the system.
PHOTOSYNTHETIC ACTION SPECTRUM OF THE COCCOLITHOPHORID, EMILIANIA HUXLEYI (HAPTOPHYCEAE): 19′ HEXANOYLOXYFUCOXANTHIN AS ANTENNA PIGMENT1,2
Authors: Haxo Francis T.
Published: August 2010

Action spectra for modulated O2 production were compared with cell absorbance in Emiliania huxleyi (Lohm.) Hay and Mohler, a marine coccolithophorid in which 19′ hexanoytoxyfucoxanthin is the major carotenoid of the photosynthetic apparatus, Photosynthetic effectiveness (action/absorption) was high throughout the spectral interval, 500–550 nm, where 19′ hexanoyloxyfucoxanthin accounted for most of the photon capture. 19′ hexanoyloxyfucoxanthin is thus considered to be an efficient antenna pigment for photosynthesis and to be preferentially associated with photosystem II. It may be a quantitatively significant light harvesting pigment for some algae of the marine environment.
IN SITU UPTAKE KINETICS OF AMMONIUM AND PHOSPHATE AND CHEMICAL COMPOSITION OF THE RED SEAWEED GRACILARIA TIKVAHIAE1
Authors: Friedlander Michael , Dawes Clinton J.
Published: August 2010

The uptake kinetics of ammonium and phosphate by Gracilaria tikvahiae McLachlan were studied under field conditions. Seaweeds, pulse fed once a week for 6 h over a 4‐week period, had maximum uptake rates of 19 μmol·g fwt−1·h−1 for ammonium and 0.28 μmol·g fwt−1·h−1 for phosphate. For both nutrients there was a positive linear correlation between uptake rate (v) and concentration (S) over the entire range of concentration tested. In a nutrient depletion experiment, the phosphate uptake curve determined over a wide range of concentrations consisted of two stages of saturation at low concentrations, and a linear phase at high concentrations. Ash free dry weight, chlorophyll a, phycoerythrin, and protein content were higher in pulse fed plants than in control plants receiving no nutrient additions, while the reverse held true for carbohydrate contents and the C/N ratios. The C/N ratio inversely correlated with ammonium and phosphate uptake rate as well as protein and phycoerythrin content, and positively with carbohydrate content.
FINE STRUCTURE OF THE IMMOBILE DINOCOCCALEANCYSTODINIUM BATAVIENSE(DINOPHYCEAE)1
Authors: Timpano Peter , Pfiester Lois A.
Published: August 2010

The fine structure of the immobile stage ofC. batavienseKlebs reveals several features which may prove helpful in understanding the parameters of the order Phytodinales. The cell covering is confluent with no thecal plates. Neither external membranes nor pores are present. The pusule tubules and collecting chamber have no external opening via flagellar pores or canals. The cell is highly vacuolate with a tonoplast‐like membrane delimiting the pusule system from the cytoplasm in the interior of the cell. Polyvesicular bodies, mitochondria with enlarged matrices containing electron‐dense bodies, vesicles which may contain flagellar hairs, crystals, and large accumulation bodies are present.
OBSERVATIONS ON THE HABIT, MORPHOLOGY AND ULTRASTRUCTURE OF CEPHALEUROS PARASITICUS (CHLOROPHYTA) AND A COMPARISON WITH C. VIRESCENS1
Authors: Chapman Russell L. , Henk Margaret C.
Published: August 2010

Cephaleuros parasiticus Karsten, an endophyte of Magnolia grandiflora L. has been examined with light, and scanning and transmission electron microscopy. The discoid thalli are composed of filaments which ramify throughout the leaf tissues beneath the epidermis. Algal filaments do not penetrate host cells, but do produce black leaf spots which have been mistaken for those caused by the fungus Glomerella cingulate (Ston.) Spauld. and Schrenk. Two distinct thallus types occur, often simultaneously on a single leaf. One bears clusters of zoosporangiate branches which seasonally emerge through the ventral (and rarely, dorsal) surface of the leaf. In contrast, the other thallus type bears gametangia which break through the dorsal leaf surface. Zoosporangia and gametangia have never been found on the same thallus. The zoosporangia are smaller than, but almost identical in shape to, those of C. virescens Kunze. Simple plasmodesmata are present in crosswalls and acetolysis indicates that little or no sporopollenin is present in the cell walls. The ultrastructure of biflagellate gametes and quadriflagellate zoospores is virtually indistinguishable from that reported for C. virescens and similar to that reported for Phycopeltis and Trentepohlia. In both gametes and zoospores there are keeled flagella, overlapping and parallel basal bodies, two 3‐layered multilayered structures with microtubular splines, and two medial compound microtubular roots. Pyrenoids, eyespots, flagellar and body scales, striated roots (or rhizoplasts), and distal bands are absent. Two presumptive mating structures are present in each biflagellate gamete, and flagellar collars occur in both types of motile cells. The extreme similarity in motile cell ultrastructure revealed in this interspecific comparison parallels that similarity revealed in intergeneric comparisons.
DEVELOPMENT OF THE FLAGELLAR APPARATUS AND FLAGELLAR POSITION IN THE COLONIAL GREEN ALGA PLATYDORINA CAUDATA (CHLOROPHYCEAE)1
Authors: Taylor Mark G. , Floyd Gary L. , Hoops Harold J.
Published: August 2010

The ultrastructure of the flagellar apparatus in pre‐inversion and inversion stages of Platydorina resembles that of Chlamydomonas in having 180° rotational symmetry and clockwise absolute orientation. Basal bodies are in a “V” configuration and connected by one distal and two proximal fibers. Alternating two‐ and four‐membered microtubular rootlets are cruciately arranged. During maturation, the basal bodies rotate and separate, and 180° rotational symmetry is lost. Simultaneously, each proximal fiber detaches from one of the functional basal bodies, and the distal fiber detaches from both. The mature apparatus has widely separated and nearly parallel basal bodies. Flagellar orientation in Platydorina is completed just after inversion and a flattening of the colony called intercalation, resulting in the pairs of flagella of neighboring cells extending from the colony in opposite directions in an alternating fashion. Flagellar orientation and separated basal bodies minimize the interference between the flagella of neighboring cells. Basal bodies and rootlets of the two intercalated halves of a colony rotate, resulting in the effective strokes of the flagella of every cell being towards the colonial posterior. The flagella of each cell beat with an effective stroke in the direction of the two inner rootlets. The flagella have an asymmetrical ciliary type beat. The rotated, separated, and parallel basal bodies, together with the nearly parallel rootlets probably are adaptations for movement of this colonial volvocalean alga. The flagellar apparatus in immature stages of Platydorina lends support to the suggestion that the alga has evolved from a Chlamydomonas‐like ancestor.