bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of the acute sickle cell vaso‐occlusive crisis in the Emergency Department: a Brazilian method of switching from intravenous to oral morphine
Authors: Campos Jessica , Lobo Clarisse , Queiroz Ana Maria Mach , do Nascimento Emilia Matos , Lima Carlos Bernardo , Cardoso Gilberto , Ballas Samir K.
Published: February 2014

Objectives

Describe the treatment of patients with vaso‐occlusive crises (VOC) in a Brazilian emergency department (ED) and the successful switch from intravenous to oral morphine.

Patients and methods

We analyzed records of 315 patients with sickle cell disease using two different protocols for pain: one in March 2010 prescribing intravenous morphine every 4 h throughout their stay, and another in March 2011 and 2012 prescribing one initial dose of intravenous morphine followed by equianalgesic doses of oral morphine every 4 h. Patients were triaged into three groups: mild, moderate, and severe VOC. The mild group was treated within 1 h after triage, the moderate within 30 min and the severe was treated immediately. Patients whose pain was not relieved within 6 h after the first dose of morphine were transferred into a different holding area of the ED where they continued to receive the same treatment for 48 h after which they were hospitalized if still in pain.

Results

The number of patients who stayed <24 h in the ED increased significantly from 63 in 2010 to 87 in 2012, and the number of admissions decreased from 26 in 2010 to 10 in 2012. The incidence of acute chest syndrome decreased from 8.5% in 2010 to 1.9% in 2012.

Conclusion

Patients treated with oral morphine stayed a shorter time in the ED, had more pain relief, were admitted less frequently, and had less acute chest syndrome. These differences may be due to environmental, cultural, psychological, and pharmacogenetic factors.
Antiepileptic drug use in seven electronic health record databases in Europe: A methodologic comparison
Authors: de Groot Mark C. H. , Schuerch Markus , de Vries Frank , Hesse Ulrik , Oliva Belén , Gil Miguel , Huerta Consuelo , Requena Gema , de Abajo Francisco , Afonso Ana S. , Souverein Patrick C. , Alvarez Yolanda , Slattery Jim , Rottenkolber Marietta , Schmiedl Sven , Van Dijk Liset , Schlienger Raymond G. , Reynolds Robert , Klungel Olaf H.
Published: February 2014

Objective

The annual prevalence of antiepileptic drug (AED) prescribing reported in the literature differs considerably among European countries due to use of different type of data sources, time periods, population distribution, and methodologic differences. This study aimed to measure prevalence of AED prescribing across seven European routine health care databases in Spain, Denmark, The Netherlands, the United Kingdom, and Germany using a standardized methodology and to investigate sources of variation.

Methods

Analyses on the annual prevalence of AEDs were stratified by sex, age, and AED. Overall prevalences were standardized to the European 2008 reference population.

Results

Prevalence of any AED varied from 88 per 10,000 persons (The Netherlands) to 144 per 10,000 in Spain and Denmark in 2001. In all databases, prevalence increased linearly: from 6% in Denmark to 15% in Spain each year since 2001. This increase could be attributed entirely to an increase in “new,” recently marketed AEDs while prevalence of AEDs that have been available since the mid‐1990s, hardly changed. AED use increased with age for both female and male patients up to the ages of 80 to 89 years old and tended to be somewhat higher in female than in male patients between the ages of 40 and 70. No differences between databases in the number of AEDs used simultaneously by a patient were found.

Significance

We showed that during the study period of 2001–2009, AED prescribing increased in five European Union (EU) countries and that this increase was due entirely to the newer AEDs marketed since the 1990s. Using a standardized methodology, we showed consistent trends across databases and countries over time. Differences in age and sex distribution explained only part of the variation between countries. Therefore, remaining variation in AED use must originate from other differences in national health care systems.

A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
Conserved charged residues at the surface and interface of epithelial sodium channel subunits – roles in cell surface expression and the sodium self‐inhibition response
Authors: Edelheit Oded , Ben‐Shahar Refael , Dascal Nathan , Hanukoglu Aaron , Hanukoglu Israel
Published: February 2014

The epithelial sodium channel (ENaC) is composed of three homologous subunits that form a triangular pyramid‐shaped funnel, anchored in the membrane with a stem of six transmembrane domains. We examined the structure–function relationships of 17 conserved charged residues on the surface of the ectodomain of human γ‐ENaC subunit by alanine mutagenesis and co‐expression with α‐ and β‐ENaC subunits in Xenopus oocytes. The results showed that Na+ conductance of cells expressing these mutants can be accounted for by two parameters: (a) the ENaC density on the cell surface as measured by the fluorescence of an α‐EnaC–yellow fluorescent protein hybrid and (b) the sodium self‐inhibition (SSI) response that reflects the open probability of the channel (Po). Overall, the activity of all 17 mutants was correlated with surface levels of ENaC. There was no significant correlation between these parameters measured for α‐ and γ‐ENaC subunit mutants at nine homologous positions. Thus, the functions of most of the homologous surface residues examined differ between the two subunits. Only four mutants (K328, D510, R514 and E518) significantly reduced the SSI response. The α‐ENaC homologs of three of these (R350, E530 and E538) also severely affected the SSI response. The cASIC1 homologs of these (K247, E417, Q421) are located at the interface between subunits, on or about the ion pathway at the rotational symmetry axis in the center of the trimer. Thus, it is likely that these residues are involved in conformational changes that lead to channel constriction and the SSI response upon Na+ ion flooding.
Enhanced sun protection of nano‐sized metal oxide particles over conventional metal oxide particles: An in vitro comparative study
Authors: Singh P. , Nanda A.
Published: February 2014

Synopsis

Background

A systematic and detailed study has been designed and conducted, taking into account some of the proposed benefits such as increased efficiency, transparency, unique texture, protection of active ingredient and higher consumer compliance of cosmetics containing nano‐sized metal oxides.

Methods

This study also presents an in vitro method to determine sun protection factor of the investigational sunscreen cream samples containing zinc oxide and titanium dioxide with a varied range of particle size. Finally, a comparative study has been conducted between metal oxide particles, conventional as well as nanoparticles.

Results

All the skin cosmetics formulated were thermally stable with a pH ranging from 7.9 to 8.2. Moreover, the fatty acid substance content and residue were found to be analogous to the standard values in each skin cosmetic. The skin cosmetics containing the titanium or zinc oxide nanoparticles were found to have improved spreadability as compared to skin cosmetics containing conventional titanium or zinc oxide particles, respectively. All skin cosmetics were found to have uniform distribution of the particles. The sunscreen creams containing zinc oxide nanoparticles and titanium dioxide nanoparticles were found to have higher in vitro sun protection factor (SPF of 3.65 for ZnO nanoparticles and 4.93 for TiO2 nanoparticles) as compared to that of sunscreen creams containing conventional zinc oxide particles (SPF = 2.90) and conventional titanium dioxide (SPF = 1.29), clearly indicating the effect of reduction in particles size, from micro to nano, on the sun protection factor.

Conclusion

Good texture, better spreadability and enhanced in vitro SPF proved the advantageous role of nanoparticles in cosmetics.
The Emergence of Lifestyle Reasoning in Return Considerations among British Pakistanis
Authors: Bolognani Marta
Published: February 2014

This article discusses the growing popularity of lifestyle reasoning in return considerations among Pakistani migrants and their children in Britain. Although lifestyle arguments are by no means new to scholarship on return migration, I argue that British Pakistanis' settlement history has led to return reasoning beyond purely economic considerations. Changes in status, power, and position, with respect to both countries of origin and settlement, have translated to a more confident capacity to aspire, and therefore to think along lifestyle considerations, whether the decision is to settle or to return. Lifestyle reasoning can therefore to be considered a sign of British Pakistanis' change in confidence about their position in the country of settlement.

Policy Implications

If the UK wants to engage with Pakistani returnees, it needs to recognize the variety of returns beyond the economic: political, lifestyle and relationship returns are all present in the array of typologies enacted by British Pakistanis

Any UK policy about return should consider that both pull and push factors influence return decisions, and those are articulated around economic, political, lifestyle, and relationship considerations.

Policy makers should consider lifestyle return reasoning a symptom of the maturation of British Pakistani citizenship in the country of settlement, rather than systematic evidence of their alienation.
Reorientation of Microfibrils and Microtubules at the Outer Epidermal Wall of Maize Coleoptiles During Auxin‐Mediated Growth
Authors: Bergfeld R. , Speth V. , Schopfer P.
Published: February 2014

Auxin‐mediated elongation growth of isolated subapical coleoptile segments of maize (Zea mays L.) is controlled by the extensibility of the outer cell wall of the outer epidermis (Kutschera et al., 1987). Here we investigate the hypothesis that auxin controls the extensibility of this wall by changing the orientation of newly deposited microfibrils through a corresponding change in the orientation of cortical microtubules. On the basis of electron micrographs it is shown that cessation of growth after removal of the endogenous source of auxin is correlated with a relative increase of longitudinally orientated microfibrils and microtubules at the inner wall surface. Conversely, reinduction of growth by exogenous auxin is correlated with a relative increase of transversely orientated microfibrils and microtubules at the inner wall surface. These changes can be detected 30–60 min after the removal and addition of auxin, respectively. The functional significance of directional changes of newly desposited wall microfibrils for the control of elongation growth is discussed.
Photosensing and Processing of Sensory Signals in Halobacterim halobium
Authors: Schimz A. , Hildebrand E.
Published: February 2014

Halobacteria detect changes in light intensity by retinal proteins, the number and identity of which are not yet unequivocally established. The sensory receptors are different from those for light energy conversion. The cells having no preferred swimming direction spontaneously reverse about every 10 s. An oscillator model has been proposed to explain this periodicity. Depending on wavelength and sign, a stimulus leads either to one prolonged interval between two reversals, the attractant response, or to a shortened interval, the repellent response. Sensory signals generated by stimulation of P‐565 and of P‐370 are integrated at a common link. Signals from other receptors may be processed by separate links. The nature of the sensory signals is not known, but the membrane potential can be excluded as a candidate. On the basis of the oscillator hypothesis the output signals of the integration links act on the oscillator and thus shift the time at which it triggers a reversal of the flagellar motor. Experiments indicate that cGMP and calcium play antagonistic roles in the oscillatory activity. Reversible methylation of specific membrane proteins influences the time during which successive signals are integrated. This reaction is assumed to terminate the lifetime of the excitatory signals and thus to allow the system to adapt.
Calmodulin Sensitivity of the Flagellar Membrane Adenylate Cyclase and Signaling of Motile Responses by cAMP in Gametes of Chlamydomonas reinhardtii
Authors: Pasquale S. M. , Goodenough U. W.
Published: February 2014

Cyclic AMP (cAMP) has been shown to be a primary signal of the agglutination‐induced mating events of flagellar tip activation, cell wall loss, and mating structure activation in the unicellular alga Chlamydomonas reinhardtii (Pasquale and Goodenough, Cell Biol. 105 (1987), 2279–2293). The flagellar membrane adenylate cyclase of Chlamydomonas is here shown to be inhibited in vitro by EGTA, La3+, and trifluoperazine, and to be stimulated in the presence of calcium by incubation with exogenous calmodulin. Also, the motility of detergent‐extracted models of Chlamydomonas is shown to be enhanced by cAMP. These observations suggest the hypothesis that the twitching motility characteristic of agglutinating Chlamydomonas gametes may be signaled by cAMP produced locally within the flagella by a calmodulin‐sensitive adenylate cyclase.
Receptor G‐Protein Interactions in the Development of Dictyostelium
Authors: Lilly P. , Klein P. , Theibert A. , Vaughan R. , Pupillo M. , Saxe K. , Kimmel A. , Devreotes P. N.
Published: February 2014

Development in Dictyostelium results in the production of a multicellular aggregate. Aggregation depends on chemotaxis to cAMP and cell‐to‐cell relay of cAMP signalling. The cAMP signalling response involves surface receptor‐mediated GTP‐dependent activation of adenylate cyclase. Studies of the mutant synag 7 indicate that a soluble protein may be involved in this activation. Wild‐type supernatants are required to restore GTP‐dependent adenylate cyclase activity to mutant lysates.

The surface cAMP receptor which initiates this response and is implicated in chemotaxis has been purified and an antiserum raised. The receptor undergoes a ligand‐induced mobility change, probably due to serine phosphorylation, when analyzed by SDS‐PAGE. Modulation of this transition is correlated with adaptation of the cells. Analysis of cells at various stages of development indicate that the receptor is most rapidly synthesized in the preaggregation stage. The antiserum was used to clone the cDNA for the receptor. Clones that have been sequenced account for about 33 000 D of the 37 000 D receptor. Hydropathy plots reveal 3 (or 4) potential membrane spanning domains; unsequenced regions are large enough to encode an additional 4 membrane spanning regions. Comparison to bovine rhodopsin reveals homology in those regions elucidated so far. Thirteen potential phosphorylation sites are present in the cytoplasmic domain and may be involved in ligand‐induced phosphorylation.
Genetics of Circadian Clocks
Authors: Feldman J. F.
Published: February 2014

The isolation of circadian clock mutants in Neurospora crassa and Drosophila melanogaster have identified numerous genes whose function is necessary for the normal operation of the circadian clock. In Neurospora many of these mutants map to a single locus called frq, whose properties suggest that its gene product is intimately involved in clock function. In Drosophila mutations at the per locus also suggest a significant role for the product of this gene in the insect clock mechanism. The per gene has been cloned and its gene product identified as a proteoglycan, most likely a membrane protein involved in affecting the ionic or electrical properties of cells in which it is located. Future progress in elucidating the mechanisms of circadian clocks are likely to come from continued analysis of clock mutants, both at the genetic and molecular levels.
Microculture and Electrofusion of Defined Protoplasts of the Moss Funaria hygrometrica
Authors: Mejía A. , Spangenberg G. , Koop H.‐U. , Bopp M.
Published: February 2014

Protoplasts isolated from protonemata of Funaria hygrometrica wild type and developmentally abnormal mutants were individually selected and cultured in microdroplets of defined, unconditioned culture medium. Up to 60 % of the microcultured wild type protoplasts regenerated whole plants after 4 weeks. Electrofusion in different combinations of defined protoplast pairs of wild type and mutated forms was performed. The products derived from one‐to‐one electric field induced fusion were efficiently microcultured and somatic hybrids were regenerated.
Evidence for a Malate Transport into Vacuoles Isolated from Catharanthus roseus Cells
Authors: Marigo G. , Bouyssou H. , Laborie D.
Published: February 2014

Malate uptake was investigated with vacuoles isolated from Catharanthus roseus cells. The uptake process showed saturation kinetics, was inhibited by organic anions, and was very strongly dependent on the pH of the medium. These data support the classical concept of an anion carrier or channel mechanism and suggest that the Hmal− form was the transported species. Moreover, malate transport was stimulated by the proton gradient across the tonoplast. The H+ translocating enzymes ATPase and PPiase are able to favour malate uptake and, in combination, exert a synergistic effect on this transfer.
Light‐ and Clock‐Controlled Leaflet Movements in Samanea saman*: A Physiological, Biophysical and Biochemical Analysis**
Authors: Satter Ruth L. , Morse M. J. , Lee Youngsook , Crain Richard C. , Coté Gary G. , Moran Nava
Published: February 2014

Leaflet movements in the legume Samanea saman are under joint control by light and a circadian oscillator. The movements are driven by massive fluxes of K+, Cl−, and H+ through pulvinar motor cell membranes. Light and the oscillator affect leaflet movements by altering the activity of ion transport systems. Some effects of light on ion transport may be mediated by the phosphatidylinositol (PI) cycle, since brief irradiation of the pulvinus with white light accelerates PI turnover.
Untersuchungen über die Überlebensfähigkeit von Endospermkulturen der Douglasie (Pseudotsuga menziesii) in vitro
Authors: Glock H. , Hattemer H. H. , Steinhauer A.
Published: February 2014

Für die Untersuchung von Umwelteffekten wurde die Wirkung von vier verschiedenen Medien auf Endosperme von Samen der Douglasie (Pseudotsuga menziesii) getestet.

Die Experimente waren so angelegt, daß die Untersuchung der Variation und die Wirkung der Umweltbedingungen für die Interpretation den Vorrang hat. Das Ziel der Versuche war, Kulturbedingungen zu ermittlen, die ein Wachstum und womöglich den Erhalt der Haploidie erlauben; damit sind im wesentlichen die Umwelteffekte, d. h. die Wirkung der drei Bereiche, organismische, interzelluläre und intrazelluläre Umwelt (zur Erläuterung dieser Begriffe s. Glock und Gregorius, Biosystems 17 (1984), 23–24), beschrieben.

Es bestätigte sich auch hier wieder, daß der genotypische Effekt bei der Interpretation der Ergebnisse nicht übersehen werden darf, denn die Endosperme der verschiedenen Sameneltern verhielten sich sowohl bei der Explantation als auch bei späteren Verpflanzungen verschieden, wie in der Darstellung genetischer Effekte zu sehen ist. Ebenso war die Reaktion von Endospermen eines Samenelters unter sich ähnlicher als die von den Endospermen verschiedener Sameneltern.

Some Experiments on Survival of Endosperm Cultures of Douglas Fir(Pseudotsuga menziesii) in vitro

The main object of the experiments was to characterize the environmental effects (= in vitro culture methods) acting upon tissue cultures of Douglas Fir endosperms.

The aim of the experiments was to find out culture conditions which can enhance growth and survival and perhaps maintain haploidy of the endosperms and to describe the effect of the different types of environment: the intercellular, the intracellular and the organismic environment (see Glock and Gregorius, Biosystems 17 (1984), 23–34).

It was found that genotypic effects were very important: the endosperms of different seed parents showed very different results, during the explantation phase as well as after transplantations. This is shown in the description of the genetical effects. The reactions of the endosperms of one seed parent were more similar to each other than the reaction between the groups of endosperms coming from different seed parents.
Immunogold Localization of Chloroplast Protein in Spinach Leaf Mesophyll, Epidermis, and Guard Cells
Authors: Rother Th. , Acker G. , Scheibe PD Dr. R.
Published: February 2014

Immunogold labelling on ultrathin sections of Lowicryl K4M embedded lower epidermis of spinach (Spinacia oleracea L.) with adhering mesophyll cells has been applied to localize five proteins, namely ribulose‐1,5‐bisphosphate carbocylase/oxygenase (EC 4.1.1.39), chloroplast coupling factor (EC 3.6.1.34), NADP‐malate dehydrogenase (EC 1.1.1.82), chloroplast fructose‐1,6‐bisphosphatase (EC 3.1.3.11) and thioredoxin m by electron microscopy in stomata. Comparative data of labelling densities of the localized proteins in chloroplasts of spongy parenchyma, epidermis and guard cells are presented. All five proteins could be detected in guard cell chloroplasts at levels little different from those found in chloroplasts of spongy parenchyma and of epidermis cells. The two light‐activated enzymes NADP‐malate dehydrogenase and fructose‐1,6‐bisphosphatase are reduced in stomata to about one third of the mesophyll concentration. Aldehyde‐sensitivity of the inspected enzymes and suitability of cryosections for immunolocalization studies on plant tissues, in comparison with resin‐embedded specimens, was investigated. Fixation with 2% glutaraldehyde resulted in no detectable decrease of antigenicity. Cryosections were found to be less suitable for immunogold labelling, since labelling densities were lower than on resin. Only labelling of the thylakoid‐bound coupling factor was comparable using both techniques.
Transmission of Electric Signals in Sieve Tubes of Zucchini Plants
Authors: Eschrich W. , Fromm J. , Evert R. F.
Published: February 2014

Membrane potentials of −;160 to −210 mV were recorded with microelectrodes inserted into meta‐phloem sieve tubes of intact zucchini plants (Cucurbita pepo L. var. medullosa Alef.). The effects of darkness, white light and colored light on membrane potential were studied. Reference electrodes were in contact with the apoplast via fluid‐filled cavities or “drinks”. Electrolyte solutions (100 mM) in the cavities could be quickly replaced by flushing with 100 mM solutions of sucrose, KCl, sorbitol, or EDTA without altering osmolarity. KCl and EDTA caused depolarization of the sieve tube membrane potential, while sucrose caused depolarization or hyperpolarization of the sieve tube membrane potential in mature or growing plant parts respectively. Recovery of the original voltage was recorded when rapid (sucrose) or slow (sorbitol) transients occurred. When two measuring circuits were installed, one in a growing fruit and the other in the petiole of the subtending mature leaf, the alteration of the sieve tube membrane potential at one site was accompanied by an alteration of the potential at the other site after a few seconds. The responses were opposite in the exporting leaf and importing fruit when sucrose was applied. The signal, transmitted via the sieve tubes, reached maximum velocities of 10 cm per second.
Movement of Abscisic Acid Across the Plasmalemma and the Tonoplast of Guard Cells of Valerianella locusta
Authors: Baier M. , Hartung W.
Published: February 2014

Uptake experiments and efflux compartmental analyses of abscisic acid (ABA) with acid treated epidermal peels of Valerianella locusta were performed to elucidate the mechanisms of transport of ABA across the plasmalemma and tonoplast of guard cells.

ABA uptake across the plasmalemma is linearly correlated with external ABA concentration in the incubation medium. Under alkaline conditions ABA‐uptake was not significantly above background, indicating that ABA uptake occurs mainly by diffusion of undissociated ABAH as the most permeable species, which is trapped afterwards in the alkaline cytosol as impermeable ABA−. Efflux analysis of ABA revealed a saturable component of ABA transfer across the tonoplast. A Woolf‐Augustinsson‐Hofstee analysis suggested the existence of two transport systems for ABA at the tonoplast. The high affinity transport system had a KM of 0.21 mol m−3 and a Vmax 85.8 amol ABA cell−1 h−1. Using the data of the uptake and efflux experiments we calculated the permeability coefficients of ABA for the plasmalemma and the tonoplast of guard cells, which are 2.46 10−7 m s–1 and 1.26 10−8m s−1, respectively. The distribution of the pH‐probe (14C)‐DMO between medium, cytosol and vacuole was investigated and used to calculate cytosolic and vacuolar pH. The vacuolar pH is too low to explain the high vacuolar ABA concentration by trapping of ABA−, whereas the cytosol is sufficiently alkaline to act as an efficient anion trap. Therefore we conclude that ABA transport across the guard cell tonoplast is catalyzed by a saturable uptake component.
Gas Exchange and Water Vapor Uptake in the Atmospheric CAM Bromeliad Tillandsia recurvata L.: The Influence of Trichomes
Authors: Schmitt Dipl.‐Biol. A. K. , Martin C. E. , Lüttge U. E.
Published: February 2014

Tillandsia recurvata is an epiphytic atmospheric CAM bromeliad without functional roots. As an adaptation to very exposed and often dry habitats T. recurvata takes up liquid water via trichomes, which cover the plant.

Gas exchange measurements also show an absorption of water vapor at the trichomes simultaneously with an increase in relative humidity at the beginning of the dark period. A similar amount of water is lost again when the relative humidity is decreased. Experiments with heat‐killed plants show that this was due exclusively to physical equilibration of the hygroscopic walls of the dead trichome cells. This effect would have prevented an accurate calculation of transpiration and conductance, but can be accounted for by substracting water vapor exchange of heat‐killed plants from that of the living tissue which yields the true water vapor conductance of the tissue. This is found to be rather low (3.37 mmol H2O kg−1 s−1) in comparison to other plants, and the proportion of total conductance due to trichomes is relatively high (0.53 mmol H2O kg−1 s−1). This explains the slow rates of photosynthesis and growth found in this plant.
Nitrogen Fixation and Nitrogen Assimilation in a Temperate Saline Ecosystem
Authors: Wollenweber B. , Zechmeister‐Boltenstern S.
Published: February 2014

As nitrogen is known to be a limiting factor for plant growth, we were interested in the relationship between soil microbial activity and the nitrogen assimilation of 5 different halophytes from 4 saline sites near the lake “Neusiedlersee”, Austria. The following were studied between May and October 1985: nitrogen fixation (15N2 and acetylene reduction): N‐mineralization; several soil characteristics and in vivo nitrate reductase activity of roots and shoots of these plants. NO−3, org. N‐ and carboxylate contents of both roots and shoots, as well as the effect of NO−3‐fertilization on the amounts of these substances, were determined on plants growing in the field during a 3‐day period in September 1985.

Fertilization led to a decrease in acetylene reduction activity at most sites, and an increase in the nitrate reductase activity of the shoots of all plants. Overall, carboxylate and organic nitrogen contents of these halophytes did not change in response to fertilization. Only in the roots of Aster tripolium and Atriplex hastata was there a marked increase in the nitrate reductase activity in response to fertilization. Species growing at the same site, such as Plantago maritima and Lepidium crassifolium showed contrasting levels of assimilatory activity. Apparent low rates of ammonification and nitrification were detected in soils from the 4 sites. The results are discussed in relation to the nitrogen and carbon economies of the microorganisms and plants.
Intracellular Solutes, Photosynthesis and Respiration of the Green Alga Blidingia minima in Response to Salinity Stress
Authors: Karsten Dipl. Biol. Ulf , Kirst Gunter O.
Published: February 2014

The effects of different salinities ranging from 7–68‰ on the internal inorganic and organic solute concentrations, and on the photosynthesis and respiration have been investigated in the green alga Bladingia minima (Näg. ex Kütz.) Kylin. The levels of the main osmotic solutes K+, sucrose and proline increased with increasing salinities and vice versa, while Na+, Mg2+, Cl− and PO3–4 played a minor role in the osmotic acclimation. In contrast to related Enteromorpha species, B. minima exhibited high NO−3 concentrations, which decreased under hypo‐ and hypersaline conditions. B. minima differs also from Enteromorpha by accumulating the tertiary sulphonium compound DMSP in osmotically significant amounts under gentle hypersaline conditions.

B. minima revealed typical characteristics of a “sun‐plant” having a high light compensation point together with a saturation of photosynthesis at high photon flux densities. The alga showed a broad photosynthetic stability under osmotic stress; only with extreme hypersaline conditions was photosynthesis partly inhibited. The rate of respiration remained constant in hypersaline media, and was stimulated under hyposaline conditions.
Tumor Transformation of Petunia hybrida via Pollen Co‐Cultured with Agrobacterium tumefaciens
Authors: Hess D. , Dressier Dipl.‐Biol. K.
Published: February 2014

Pollen preparations usually show a high nuclease activity. Therefore, to avoid DNA degradation, co‐cultures of pollen and Agrobacterium tumefaciens were evaluated as a new tool in gene transfer experiments. As a model system, Petunia pollen was co‐cultured with an A. tumefaciens wild strain. The co‐cultured pollen was used for pollination of Petunia flowers. The seeds obtained were germinated and one cotyledon per seedling was removed and put stalk upwards on nutrient agar. In 80% of the cotyledons a callus developed from the cut surface of the stalks which was screened for tumor transformation on hormone‐free medium. In repeated subculturing some calli maintained growth on hormone‐free medium. Two of these calli were habituated. One callus, the best growing one, showed on Southern blot analysis a distinct hybridization signal at 3.2 kb when probed with Hind III fragment 22 DNA, covering two genes responsible for hormone free growth. This is the exact size that could be expected when plant material has been transformed with T‐DNA. Another callus gave a hybridization signal at 2 kb which could only be explained with chromosomal rearrangement. In these two calli there was no co‐transformation of the nos‐gene: nopaline synthase activity could be detected from none of the calli, and none of the calli DNAs hybridized when probed with the nos‐gene. Bacterial contamination could be excluded by probing the DNAs with virfragments.
Anatomical Studies of Haustorium Ontogeny and the Remarkable Mode of Penetration of the Haustorium in Nuytsiafloribunda (Labill.) R. Br.
Authors: Beyer Christine , Forstreuter W. , Weber H. Chr
Published: February 2014

The development and structure of secondary haustoria of Nuytsia floribunda are described and compared with other Santalalean haustoria.

After establishing contact with the host root, cortical folds of the haustorium grow around the root in separate directions and fuse forming a ring around it. At an early stage of development, meristematic tissue differentiates in the interior proximal part of the haustorium. Zones of collapsed layers are present in the outer cortical region. Subsequently, in the proximal part, two vascular cores, two lysigenous cavities and extensive masses of sclerenchyma develop prior to penetration of the host root. The sclerenchymatous cells form a characteristic structure, described as the sclerenchyma prong.

During penetration the intrusive part of the haustorium reaches not only the host xylem but continues growing downwards until it entirely splits the host root. Comparable to a guillotine, the sclerenchyma prong is directly involved in this remarkable process. The sclerenchyma prong finally lies in the distal part of the haustorium.

Following this mechanical slicing of the host root, tube‐like cells of the intrusive part actively penetrate the host xylem in an axial direction.
On an Inhibitor of Ferredoxin Catalyzed Cyclic Photophosphorylation in Thylakoid Membranes*
Authors: Trebst Achim , Wietoska Helga
Published: February 2014

Dibromo‐ and diiodo‐naphthoquinones are shown to be inhibitors of the cytochrome b6/f complex in isolated thylakoid membranes from spinach chloroplasts. Dibromo‐naphthoquinone inhibits ferredoxin catalyzed cyclic photophosphorylation at 0.1 μM concentrations, but non cyclic e‐flow only at 10 μM. It does not inhibit cyclic systems with artifical cofactors, nor non‐cyclic electron flow from duroquinol through photosystem I via the cytochrome b6/f complex. Dibromo‐naphthoquinone does however, lower the stoichiometry for ATP formation in the duroquinol donor system. This inhibitory pattern is quite different from that of DBMIB, but very similar to that of antimycin. This antimycin‐like behaviour of these inhibitors is interpreted to indicate a) the existence of a Qc site in the cytochrome b6/f complex and its obligate function in ferredoxin catalyzed cyclic electron flow and b) a non‐essential role of the Qc site in non‐cyclic electron flow, but which — when operative — pumps an extra proton across the thylakoid membrane increasing the ATP yield.
Photosynthetic Characteristics and the Ratios of Chlorophyll, β‐Carotene, and the Components of the Xanthophyll Cycle Upon a Sudden Increase in Growth Light Regime in Several Plant Species*
Authors: Demmig‐Adams B. , Winter K. , Winkelmann E. , Krüger A. , Czygan F.‐C.
Published: February 2014

Among three species, Gossypium hirsutum, Rhizophora mangle, and Monstera deliciosa, which were transferred from low to high growth PFD, only small decreases in the efficiency of photochemical energy conversion were observed in those plants which exhibited an increase in photosynthetic capacity. Leaves of plants which showed no increase in photosynthetic capacity experienced a continuous decrease in photochemical efficiency, accompanied by a more pronounced loss of chlorophyll than that observed in the former group. In all species marked increases in the xanthophyll/β‐carotene ratio resulted from small increases in lutein, and several‐fold increases in the sum of the three components of the xanthophyll cycle, zeaxanthin, antheraxanthin, and violaxanthin. A strong increase in the level of zeaxanthin was only partially matched by a decrease of violaxanthin to zero, and was further paralleled by a decrease in β‐carotene. Antiparallel changes in the sum of zeaxanthin + antheraxanthin + violaxanthin and β‐carotene between morning and evening were observed in all species. These diel changes were overlaid on a net increase in β‐carotene as well as total carotenoid content in those plants in which photosynthetic capacity increased. In those, however, which exhibited no photosynthetic acclimation upon transfer to high light, a decrease in both β‐carotene and total carotenoid content was observed. Rhizophora mangle grown at 100 % seawater exhibited a particularly high capacity for increasing the level of zeaxanthin in response to high light.
Photoacoustic Spectroscopy and its Application in Plant Science
Authors: Buschmann C.
Published: February 2014

The principles of photoacoustic spectroscopy are outlined. This new and still developing technique enables one to detect non‐radiative de‐excitation processes. It is possible to distinguish between signals emenating from different depths of the sample. In plant science photoacoustic spectroscopy has mainly been applied in photosynthesis research. Here it allows the detection of gross oxygen evolution and gives information about the energy balance of the primary photosynthetic reaction.
Implications of Control Theory for Homeostasis and Phosphorylation of Transport Molecules*
Authors: Hansen U.‐P.
Published: February 2014

Homeostasis of a cytosolic substrate (e.g. H+) can be achieved by transmembrane transport. Control theory implies that the involved activation and deactivation of a transport molecule (as observed in patch clamp experiments) requires input of energy. This energy can be provided by a so‐called non‐consuming binding site or by other sources and is necessary in order to achieve asymmetric rate‐constants required for an efficient integral controller. Another important prediction of control theory is the involvement of two different binding sites for the substrate and its antagonist in order to define a non‐zero set‐point.

The kinetic behavior of a homeostatic feed‐back loop is calculated. The system can generate weakly damped oscillations or exponential responses. Numerical calculations using data from the pH‐controller of Nitella show that a buffer is necessary in order to explain the observed long periods of 1 hour/cycle. Theoretically, the damping factor can originate from shunting transporters or from special terms of the biochemical reaction schemes. The effect of shunting transport systems is demonstrated in the case of data from the light‐effect on H+‐fluxes in Nitella.
The Plasma Membrane Ca2+‐Pump of Plant Cells: A Radiation Inactivation Study
Authors: Rasi‐Caldogno Franca , Pugliarello Maria Chiara , Olivari C. , De Michelis Maria Ida , Gambarini Grazia , Colombo Paola , Tosi G.
Published: February 2014

The functional molecular weight of the plasma membrane Ca2+‐ATPase of radish (Raphanus sativus L.) seeds was determined by measuring the Ca2+‐dependent ATPase activity and the MgATP‐dependent Ca2+ transport activity of membrane samples irradiated, in the lyophilized state, with γ rays from [60Co] source. The results gave a target size of about 270,000 dalton for both the measured activities, thus confirming (i) that both activities are catalyzed by the same enzyme and (ii) the similarity between the plasma membrane Ca2+‐ATPase of higher plants and that of the erythrocytes.
Growth of Anacystis in the Presence of Thiosulphate and its Consequences for the Architecture of the Photosynthetic Apparatus
Authors: Koenig F.
Published: February 2014

With the aim of obtaining information on the degree of flexibility maintained in cyanobacteria in context with their phylogenetic position, Anacystis was grown in the presence of thiosulphate, oxidized in a photosystem I (PSI) dependent reaction (KM 7.4 × 10−3 M thiosulfate). Besides DBMIB, only o‐phenanthroline and p‐hydroxymercuribenzoate blocked thiosulphate‐dependent PSI activity to some extent; iodonitrothymol, DCMU and cyanide had no influence. Growth of Anacystis in the presence of thiosulphate induced a reorganization of the photosynthetic apparatus characterized by a shift in the PSII/PSI ratio in favor of PSI, comparable to low light conditions. Capability for oxygenic photosynthesis never completely disappeared; structural elements of PSII were retained in the membrane to a certain degree. The antenna pigment system signalled high light under conditions of thiosulphate oxidation as judged from the ratio of phycocyanin to chlorophyll. Besides a shift in the ratio of PSII to PSI components, the polypeptide pattern of thylakoids from thiosulphate grown cells shows several additional components compared to the controls and, moreover, higher concentrations of some polypeptides present in the controls, particularly a Mr 41000 polypeptide. The process of thiosulphate oxidation appears bound to the thylakoid membrane.
Auriculora byssomorpha, a Tropical Lichen with a Remarkable Developmental Morphology*
Authors: Henssen A. , Titze A.
Published: February 2014

The thallus, pycnidia, and the structure and ontogeny of the ascocarp in Auriculora byssomorpha are described and illustrated. The ontogeny of the apothecia is characterized by the repeated formation of new hymenia within the subhymenial layer. The development of the first hymenium is gymnocarpous but the de novo differentiation of new hymenia, each beneath the next older disintegrating one, gives rise to a peculiar type of secondary hemiangiocarpy. Portions of the decaying hymenia and adjacent subhymenial tissue frequently remain fastened to the apothecial margin and disc in the shape of ear‐like appendages or as superimposed layers. In aged apothecia such decaying tissue may form a sheath around the apothecial margin and on the disc. The systematic position of the genus is briefly discussed.
Regulation of LHCa‐Polypeptide‐Biosynthesis in the Phototrophic Green Alga Chlamydobotrys stellata*
Authors: Wiessner W. , Kohnke B. , Kloppstech K. , Mende D. , Radunz A. , Winter J.
Published: February 2014

The light‐harvesting chlorophyll‐protein system of the phototrophic alga Chlamydobotrys stellata consists of the common photosystem II‐related chlorophyll a/b‐protein complex LHCII and a special photosystem I‐connected chlorophyll protein complex, called LHCa (Brandt et al. 1982, 1983) which is present after cultivation of the algae with acetate as carbon source and in absence of carbon dioxide. LHCII consists of three polypeptides (Mr.103 27, 25.5 and 25), whereas only one polypeptide (Mr.103 24) was obtained after polyacrylamide gel electrophoresis of LHCa. The specific LHCII‐precursor‐polypeptides (Mr.103 38, 32, 26) were among the translation products of poly(A+)mRNA from autotrophic or photoheterotrophic algae. The LHCa‐precursor‐polypeptide (Mr 30 000) was found when the alga had been cultivated in the presence of acetate. The data support the assumption that LHCa‐biosynthesis is controlled by the actual growth conditions at or close to the transcriptional level.
Recent Molecular Approaches to the Physiology of the Plasma Membrane Proton Pump
Authors: Serrano R.
Published: February 2014

During the last 3 years, genes for plasma membrane H+‐ATPases from fungi, protozoa and plants have been isolated. Sequence similarities indicate that H+‐ATPases constitute a separate group with the family of ATPases with phosphorylated intermediates. Yeast is a convenient model system to approach the physiology of H+‐ATPases by recombinant DNA methodologies. A mutational analysis of yeast H+‐ATPase has demonstrated that the enzyme is essential and rate‐limiting for growth. Intracellular pH homeostasis is one of the crucial functions of H+‐ATPase. In addition, there are indications for the direct energization of some essential transport system. The regulation of ATPase activity is probably mediated by an interaction between the active site and an inhibitory domain at the carboxyl‐terminus.
Thallus Formation of the Cyanobacterial Lichen Peltigera didactyla from Soredia under Laboratory Conditions
Authors: Stocker‐Wörgötter Elfie , Türk R.
Published: February 2014

Formation of mature thalli with soredia occurred within an average cultivation time of 5 to 6 months. The size and growth form of the thalli (mussel‐shaped and branched type) were dependent upon the number of the soredia which were involved in the thallus‐forming process. Not only soredia amalgamated forming a soredia‐field, but also whole lobes fused during development.

Contamination problems with soredia were partially overcome by using soredia from cultivated thalli.
Isotopic Fractionation of Hydrogen in Plants
Authors: Smith B. N. , Ziegler H.
Published: February 2014

The naturally‐occurring stable isotopes deuterium and hydrogen are fractionated by a number of physical and biological processes. Deuterium has a tendency to precipitate out first from a moist air mass. Thus ground water will become isotopically lighter with an increase in latitude, altitude, or distance inland. Water taken up by the plant from the soil undergoes little change until evapotranspiration results in leaf water becoming isotopically heavier. Thus hydrogen isotopes in plants can reveal something of geography (groundwater) and climate. Hydrogen isotopes undergo little fractionation by passage through the food chain, although plant parasites tend to be enriched in D as compared to their hosts, possibly due to higher rates of transpiration in the parasitic plants. The splitting of water in photosynthesis results in the lighter isotope being incorporated into organic matter. An even larger isotopic fractionation results during lipid synthesis and other processes involving the pyruvate dehydrogenase complex. Differences in metabolic pathway between species can be detected by D/H ratios. Hydrogen isotopic differences can be detected between CAM, C4, and C3 species. Within C4 plants, the NADP‐ME plants are isotopically distinguishable from NAD‐ME and PEP‐CK plants.
Ultrastructural Observations of Papaver rhoeas Mature Pollen Grains
Authors: Cresti M. , Milanesi C. , Salvatici P. , Van Aelst A. C.
Published: February 2014

The mature pollen grain of Papaver rhoeas is bicellular. The vegetative cell contains numerous mitochondria; endoplasmic reticulum is not very extensive and there are few ribosomes and plastids. Golgi bodies are in a very active state. The generative cell is lobed and spindle‐shaped. The cytoplasm contains many, generally longitudinally arranged, bundles of microtubules. Other organelles are few in number, and include mitochondria, Golgi bodies and short cisternae of endoplasmic reticulum.
Partial Turgor Pressure Regulation in Chara canescens and its Implications for a Generalized Hypothesis of Salinity Response in Charophytes
Authors: Winter U. , Kirst G. O.
Published: February 2014

Concentrations of ions and sucrose in the vacuolar sap of Chara canescens growing in an oligohaline lake (1.5 ‰) were estimated over the main growth period of the plants. During fructification vacuolar sap contained a mean of 41 mol m−3 (range 10.2–61.8) sucrose. The mean turgor pressure was 239 mosmol kg−1 (range 219–264).

In long‐ and short‐term experiments these plants were subjected to increasing salinities up to 22 ‰. When salinity was increased from 1.5 to 4.4 ‰ turgor pressure was restored to only 80 % of the initial value. This reduced level of turgor pressure was maintained up to a salinity of 22 ‰. The increase in vacuolar osmotic potential was due to the monovalent ions Na+, K+ and Cl−. The relative amounts of Na+ and K+ participating in the regulation process were dependent on external salinity.

The regulatory mechanisms observed in the brackish water species Ch. canescens are compared with those reported from freshwater and euryhaline species.
Regeneration of Plantlets from Callus Cultures of Chamaecytisus purpureus and Chamaecytisus austriacus (Leguminosae)*
Authors: Greinwald R. , Czygan F.‐C.
Published: February 2014

Plant regeneration via organogenesis and embryogenesis was obtained from callus cultures of Chamaecytisus purpureus and Chamaecytisus austriacus. While 2,4‐D (4 or 0.5 mg/l) proved highly efficient for callus induction, a combination of 0.1 mg/l IBA and 10 mg/1 BAP induced a high frequency of shoots from the calli. It is shown that, beside the growth factors, the composition of the basal medium represents a critical factor for regeneration. With increasing culture age, a strong reduction of the differentiation capacity was observed.