bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple Effects of Lysophosphatidylcholine on the Activity of the Plasma Membrane H+‐ATPase of Radish Seedlings*
Authors: De Michelis Maria Ida , Papini R. , Pugliarello Maria Chiara 
Published: February 2014

Abstract:We analyzed the effect of lysophosphatidylcholine (lysoPC) on the activity of the plasma membrane (PM) H+‐AT‐Pase measured at pH 6.3 or 7.5 in inside‐out PM vesicles isolated from germinating radish seeds. LysoPC stimulated PM H+‐ATPase at both pHs, but the dependence of the effect on lysoPC concentration was different: at pH 6.3 maximal stimulation was observed with 40 to 200 μg ml−1 lysoPC, while at pH 7.5 a sharp peak of activation was observed at about 50 μg ml−1 lysoPC, higher concentrations becoming dramatically inhibitory; this inhibitory effect was considerably reduced in the presence of 10% (v/v) glycerol. In trypsin‐treared PM lysoPC stimulated the H+‐ATPase activity assayed at pH 6.3, but only marginally that assayed at pH 7.5. LysoPC increased both Vmax (from 190 to 280nmol min−1 mg−1 prot) and apparent KM (from 0.15 to 0.3 mM) of the H+‐ATPase at pH 6.3, while it increased Vmax (from 120 to 230 nmol min−1 mg−1 prot) and decreased apparent Km (from 0.8 to 0.4 mM) at pH 7.5. Low concentrations of Nacetylimidazole (10 to 50 mM), which modifies tyrosine residues, abolished the stimulation by lysoPC of the PM H+‐ATPase activity at pH 7.5, but not that observed at pH 6.3. These results indicate that lysoPC influences the PM H+‐ATPase through different mechanisms, and that its effect can only partly be ascribed to its ability to hamper the inhibitory interaction of the regulatory C‐terminal domain with the catalytic site. N‐acety‐limidazole did not affect the stimulation of PM H+‐ATPase by controlled trypsin treatment or by fusicoccin, indicating that the requirement for the tyrosine residue(s) modified by low Nacetylimidazole concentrations is specific for lysoPC‐induced displacement of the C‐terminal domain.
Changes in the CO2 Concentrating Mechanism During the Cell Cycle in Dunaliella tertiolecta
Authors: Sültemeyer D. 
Published: February 2014

Abstract:Synchronised cells of Dunaliella tertiolecta were used to investigate the expression of the CO2 concentrating mechanism over the cell cycle during growth in either ambient air (low Ci cells) or air enriched with 5% CO2 (high Ci cells). The cultures were analysed for extracellular carbonic anhydrase activity, affinity of photosynthesis for inorganic carbon (Ci) and the ability to accumulate Ci. In high Ci cells, carbonic anhydrase activity changed between 2 − 4 units mg−1 Chi during the light‐dark rhythm showing no clear periodicity. Similarly, the apparent affinity for Ci remained rather constant over the cell cycle. This was judged from the Ci concentrations required for half maximum rate of photosynthesis (K1/2(Ci)) of 72 − 80μM. In the same cells the accumulation ratio of internal Ci versus external Ci ranged between 5 and 9.5 without a clear rhythm. In contrast, these parameters showed distinct periodical changes in synchronised low Ci cells. Carbonic anhydrase activity changed from 10 to 350 units mg−1 Chl with maximum and minimum activities occurring in the middle and at the end of the light period, respectively. The K1/2(Ci) values showed similar periodicity ranging between 13 − 36μM. In addition the accumulation ratio increased up to 30 in the middle of illumination and decreased to its lowest level of 12 at the end of the light period. These results indicate the presence of a common step in regulating the induction of the measured parameters and that light is not an absolute requirement for the induction of the CO2 concentrating mechanism in synchronous low CO2 grown cells of Dunaliella tertiolecta.
Indigenous Medicinal Plants in Mexico: the Example of the Nahua (Sierra de Zongolica)
Authors: Weimann Claudia , Heinrich M. 
Published: February 2014

Abstract:As in most peasant cultures medicinal plants are a very important resource for the Nahua of the Sierra de Zongolica (Mexico). Documentation of the current indigenous medicinal uses of 203 plants in this region was conducted during 18 months of fieldwork. The 816 individual reports documented were divided into nine groups of indigenous uses. The frequency of usage of the individual plants reported was employed in the analysis of the ethnobotanical importance of the respective plants. Plants cited more frequently in a group of indigenous uses are regarded as of greater ethnobotanical importance than those cited only by a few informants. Data on phytochemistry, pharmacology and ethnobotany from the scientific literature were used to evaluate possible biological or pharmacological and toxicological effects of some particularly important plants. For most plants detailed studies on these actions are still lacking, which would allow a conclusive evaluation. This ethnobotanical evaluation forms the basis for such studies which have been started on some plants, and for better understanding their potential as minor economic products of the region. These uses may also give incentives to the conservation of the local biodiversity.
Phenology and Pollination Ecology of Three Brazilian Fig Species (Moraceae)
Authors: De Figueiredo R. A. , Sazima Marlies 
Published: February 2014

Abstract:The phenology and pollination ecology of three native fig species were studied in southeastern Brazil. Populations displayed continual syconia production, with one species showing intra‐tree flowering asynchrony. Pollination of the fig flowers was necessary for the development of the syconia; lack of pollination induced abortion of syconia. All three species follow the general pattern of pollination known for figs, but the behavior of the pollinator wasps, Pegoscapus spp., differed in some aspects from those of other neotropical and paleotropical fig wasps, mainly with respect to pollen loading and unloading during pollination. The longevity of Pegoscapus wasps outside the syconium was about two days.
Nuclear DNA Amounts in Palms (Arecaceae)
Authors: Röser M. , Johnson M. A. T. , Hanson L. 
Published: February 2014

Abstract:Nuclear DNA amounts are reported for 83 species and 53 genera of palms, covering all of the six subfamilies. 4C DNA contents range between 3.89 and 55.62 pg in diploids, showing an approximate 14.3‐fold variation in genome size. Polyploids have DNA contents of up to 156.40 pg/4c which demonstrates a 40.2‐fold variation. Diploids with high DNA contents occur in three subfamilies of palms (Coryphoideae, Calamoideae, Arecoideae), and seem to be further restricted to particular tribes or subtribes (Thrinacinae, Borasseae, Lepidocaryeae, Caryoteae, some subtribes of Areceae). Palms from the subfamilies Nypoideae and Phytelephantoideae have the lowest DNA amounts, followed by the Phoeniceae and the Corypheae: Livistoninae from the subfamily Coryphoideae. Although DNA amounts in some genera and subtribes are usually constant, e.g., in Phoenix, Phytelephas, the Livistoninae, Dypsidinae, diploid Butiinae), considerable variation occurs at the diploid level in some large and apparently actively evolving genera such as Chamaedorea, Pinanga, Cenoma and possibly Bactris. Formaldehyde fixation is recommended for palms, as conventional ethanol‐acetic acid fixation has proved to be unsuitable for DNA estimation of Feulgen‐stained nuclei by microdensitometry, since it can lead to errors up to 2.5‐fold in extent. Chromosome counts are reported for 72 of the species studied, of which 42 are new.
Root Anatomy and Mycotrophy (AM) of the Achlorophyllous Voyria truncata (Standley) Standley & Steyermark (Gentianaceae)
Authors: Imhof S. , Weber H. Chr 
Published: February 2014

Abstract:Roots of Voyria truncata retain the primary root structure even though they can grow as thick as 2 mm in diameter. These root diameters are due to a retained capability for cell division in the cortex parenchyma. This is explained as a vital adaptation to its life form. Based on the extraradical mycelium, the mode of penetration, the structurally incompatible intraradical phase, the presence of intercellular vesicles in the root cortex, and the occurrence of immediate hyphal bridges from arbuscular mycorrhizal roots of neighbouring plants, the mycorrhiza of V. truncata is described as an arbuscular mycorrhiza (AM), although the characteristic arbuscles are missing. Special features of the AM in V. truncata are interpreted as an improved efficiency in taking advantage of the mycorrhiza. Root connections with roots of neighbouring plants are common and preferred locations for fungal infections. An evolutionary tendency towards parasitism of higher plants is discussed.
Terrestrial Biomass‐Reconstruction for the Pleniglacial and the Holocene Climatic Optimum Around 7000 cal yr BP in Europe
Authors: Gliemeroth Anne Kathrin 
Published: February 2014

Abstract:The aim of this research was to estimate the former below‐ and aboveground biomass during the Last Pleniglacial (22,000 cal yr BP) and during the Holocene climatic optimum, the Atlantic Period (7,000 cal yr BP). Vegetation distributions and soil conditions during these periods were reconstructed according to published literature. Using the present‐day bio‐masses of similar (but not identical) vegetation and soil types as analogues, estimates of the terrestrial biomass were made for 22,000 and 7,000 cal yr BP. Biomass was low during the Pleniglacial, representing only 5.0 to 12.5 Gt. This reflects weak soil development under cold climatic conditions, combined with soil erosion due to severe frost and strong wind. The results are compared with other biomass reconstructions for the Pleniglacial. The values for terrestrial biomass of the Pleniglacial presented in this paper are much lower than the results of the various studies for this time slice. These differences are likely to be related to the method applied. Biomass was high during the Holocene climatic optimum around 7,000 cal yr BP, representing 261 to 325 Gt compared to 232 to 273 Gt in the present potential situation and 165 to 197 Gt in the present‐day real situation. This reflects intensive soil development under warm and moist conditions during the climatic optimum of the Holocene. These results demonstrate the fluctuation of C‐content in terrestrial ecosystems since the Last Glacial Maximum on the European continent.
Essential Oils with 1,2‐Epoxy‐p‐menthane Derivatives from Mentha spicata Plants Growing Across the Island of Crete
Authors: Kokkini Stella , Karousou Regina , Lanaras T. 
Published: February 2014

Abstract:The essential oil content and composition of Mentha splcata plants, collected from 11 localities, scattered across the island of Crete (S. Greece), have been studied. The qualitative and quantitative essential oil analyses by means of CC and GC‐MS, have shown that these are characterized by a high quantity of trans‐piperitone oxide and/or piperitenone oxide. The pattern of essential oil quantitative variation follows a NW→SE direction on Crete. Along this direction, the total essential oil content of the plants increased whereas, the essential oil components formed via the pathway leading to the formation of cis‐piperitone oxide are gradually substituted by those leading to the formation of trans‐piperitone oxide.
Plant Polyamines in Reproductive Activity and Response to Abiotic Stress*
Authors: Galston A. W. , Kaur‐Sawhney R. , Altabella T. , Tiburcio A. F. 
Published: February 2014

Abstract:In this review we will focus on two areas in which the accumulated evidence for a critical physiological role of polyamines is becoming compelling, i.e. reproductive activity and response to abiotic stress. Regarding reproductive behavior, it seems clear that polyamines are members of the array of internal compounds required for flower initiation, normal floral organ morphogenesis, fruit growth and fruit ripening in particular plant species. Abiotic stresses such as osmotic stress can “turn on” arginine decarboxylase (ADC) genes, resulting in a rapid increase in their mRNA levels. Localization of ADC enzyme in the chloroplast suggests a role of PAs in the maintenance of photosynthetic activity during senescence responses induced by osmotic stress. We envisage that the use of transgenic plants and improved molecular probes will resolve in the near future the physiological significance of stress‐induced changes in PA metabolism as well as the role of these compounds in reproductive activity.
Solving a Puzzle Piece by Piece: Sexual Development in the Basidiomycetous Fungus Schizophyllum commune
Authors: Kothe Erika 
Published: February 2014

Abstract:In the homobasidiomycete fungus Schizophyllum commune recognition of mates is based on four multiallelic genetic loci. While Aα and Aβ independently but redundantly regulate formation of clamp cells, nuclear migration is under control of the B loci Bα and/or Bβ. In the A loci two homoeodomain transcription factors, Y and Z in Aa and one yet, V in Aβ, are encoded which form acitve heterodimers only if different specificities are combined (like Y3 Z4), e.g. via mating of strains differing in Aα loci. In both Bα and Bβ, pheromone receptors and several pheromone genes habe been found. While the homoeodomain transcription factors are thougth to directly activate downstream genes, a signal transduction cascade culminating in activation of target genes is postulated for B‐regulated development. Only if both A and B pathways are turned on, fruit body formation and spore production are observed.
Some Aspects of the Importance of Genetic Diversity in Phragmites australis (Cav.) Trin. ex Steudel for the Development of Reed Stands
Authors: Koppitz H. , Kühl H. , Hesse K. , Kohl J.‐G. 
Published: February 2014

Abstract:Various sites of Phragmites australis in Germany (Uckermark and Mark Brandenburg) and sites in Hungary and Denmark were investigated by PCR fingerprinting in order to determine their genetic diversity. Genetic similarities were calculated and, based on this, a cluster analysis was performed. The genetic similarity of reed clones around one lake ranged from between 70 to 100%, that of clones from different lakes was clearly lower. The further apart the clones were situated from each other, the less similar they were. At a wetland site near the shore a sudden colonisation by several new Phragmites clones was observed. This site was located in front of a well established genetically almost homogenous stand within the eulittoral. All the results are discussed in connection with a proposed model of establishment and development of water reed stands: colonization, selection of best adapted clones by competition and the stability of stands.
Seed of Cercis siliquastrum L (Leguminosae, Caesalpinioideae): Reserves and their Utilization after Germination
Authors: Rascio Nicoletta , Mariani Paola , Perin Vilma , Vecchia Francesca Dalla , Castaldo Paola 
Published: February 2014

Abstract:An ultrastructural study on the reserves stored in cotyledons and endosperm and on their utilization after germination has been carried out in Cercis siliquastrum seeds. The observations have shown that all the cotyledonal reserves of proteins and lipids are used during seedling growth. However, inside the endosperm cells only the protein reserves are depleted, and large quantities of lipids remain undigested. In both cell walls and intercellular spaces of the endosperm cells huge masses of polysaccharide reserves are stored. However, only the polysaccharides inserted in the cell walls are dismantled, while those located in the intercellular spaces are not attacked by the lytic enzymes. Some hypotheses regarding the possible roles of those endospermic non‐nutritional materials in the strategies of seed germination and seedling growth are suggested.
Reproduction and Hybridisation in the Genus Rosa, Section Caninae (Ser.) Rehd.
Authors: Wissemann V. , Hellwig F. H. 
Published: February 2014

Abstract:Crossing experiments were carried out in order to investigate the importance of apogamy in relation to autogamy, geitonogamy and xenogamy in the reproductive biology of pentaploid members of the genus Rosa, section Caninae (Ser.) Rehd. About 10,000 seeds from 900 crossing experiments were examined, 4500 of them for both filling of the grain and viability of the embryo. The results were compared with experimental reports and literature dating from 1753 to 1995. Apomictic reproduction was shown to be possible in all species of the section tested, but viable seed yields were only about 5% of those produced by xenogamy. This contradicts the hypothesis of Fagerlind (1940,1944,1945,1950) and Custafsson and Hakansson (1942), but supports the results of Matsson (1912) and Schwertschlager (1915). The number of viable seeds increased in the order apogamy, autogamy, geitonogamy to xenogamy. Reciprocal crossings showed significant differences in the number of seeds produced in the hip. This contradicts the hypothesis on the genomic constitution of the pentaploid Caninae with unbalanced heterogamy, as advocated by Hurst (1927) and Custafsson and Hakansson (1942).
Phosphate and Sulfate Activate the Phosphoenolpyruvate Carboxylase from the C4 Plant Cynodon dactylon L.
Authors: Salahas G. , Hatzidimitrakis K. , Georgiou C. D. , Angelopoulos K. , Gavalas N. A. 
Published: February 2014

Abstract:The effect of phosphate, sulfate and other inorganic ions on the activity of phosphoenolpyruvate carboxylase (PEPC) from the C4 plant Cynodon dactylon were investigated for the first time, as well as their interaction with Clc‐6‐P, AMP and ma‐late. Activation of PEPC by phosphate and sulfate ions was demonstrated and it was not dependent on the accompanying cations, something that was not clarified for PEPCs from other plant sources. No activation of this enzyme was observed by nitrate. PEPC activation was found to be competitive with glucoses‐phosphate (Clc‐6‐P) and AMP stimulation and less sensitive to malate inhibition. This work showed that PEPC from C4plants could exhibit similar activation properties with the enzyme from CAM plants and different activation properties in plants of the same type, rendering the study of this enzyme from different plant sources necessary.
The Pollinators of the Malagasy Star OrchidsAngraecum sesquipedale, A. sororiumandA. compactumand the Evolution of Extremely Long Spurs by Pollinator Shift
Authors: Wasserthal L. T. 
Published: February 2014

Abstract:The pollination process of the extremely long‐spurred orchidsAngraecum sesquipedaleandA. sororiumis described and documented here for the first time. The pollinaria and viscidia load was examined in moths captured in central and south Madagascar. Visits to orchids by hawkmoths were rarely observed in the field and were therefore systematically recorded in large flight tents using a night‐vision video technique and flashlight photography.Angraecum sesquipedalein Fort Dauphin is pollinated byXanthopan morgani praedictaandA. sororiumon Mt. Angavokely byCoelonia solani. By combining a deep nectar spur of extraordinary length with a protruding labellum functioning as a landing platform, these orchids overcome the moth's stereotypic swing‐hovering flight thus enabling full insertion of the long tongue.Angraecum compactumin Forêt d'Ambohitantely is pollinated by both the shorter and longer‐tongued forms ofPanogena lingenswhich never swing‐hover but is also exploited byX. morganiandC. solaniwith wastage of pollinaria. The duration of tongue insertion, nectar exploitation and tongue withdrawal were analyzed: legitimate and illegitimate visitors differ in their time budget and approach to the flower. Nectar volume, nectar level and sugar concentration ofA. sesquipedaleandA. sororiumwere compared with the nectar requirements of the pollinating hawkmoths. The evolution of very long spurs in these orchids is likely to have involved a series of pollinator shifts. The orchids adapted to different hawkmoth species with increasingly long tongues which primarily evolved to avoid predator attacks during visits to less specialized flowers. This “pollinator shift” model modifies the classical “coevolutionary race” model. The relevance of the taxonAngraecum bosseriSenghas is questioned.
A Spectroscopic View of Some Recent Advances in the Study of Blue Light Photoreception*
Authors: Horwitz B. A. , Gloria M. , Berrocal T. 
Published: February 2014

Abstract:The blue to UV‐A region of the spectrum, spanning the region of about 320–520 nm, strongly influences the growth and development of plants and fungi. Photomorphogenesis in plants is, to a great extent, controlled by phytochrome, but there are unique contributions of the blue region, which cannot be duplicated by any amount of red light. Phototropism is, with few exceptions, a purely blue light response. In fungi, the blue region dominates the photocontrol of growth and development, though some red light effects have been reported. Many blue light action spectra fit the definition of cryptochrome, a pigment class defined by its UV‐A and blue peaks. The action spectrum, if measured to sufficient resolution, displays several minor maxima or shoulders in the blue region which call to mind the vibrational levels of carotenoids and flavins. Recent molecular genetic studies, as well as photobiological work, have shown that some cryptochromes are related to the DNA repair enzyme photolyase, while others appear genetically and spectroscopically distinct. In this review, we have applied established criteria from photobiology, in particular, comparison of action spectra with absorption spectra, to these recent results. It is apparent that photolyase homologs such as CRY1 can explain the blue light portion of the action spectrum for hypocotyl elongation, assuming participation of the oxidized flavin. In fungi, the photoreceptor question remains open. Identification of the nph1 gene in Arabidopsis may soon lead to a photoreceptor for higher plant phototropism. Also, we present a possible solution to the most recent version of the long‐standing flavin‐carotenoid controversy, the zeaxanthin hypothesis for higher plant phototropism. In conclusion, there appear to be at least three classes of cryptochromes.
SIMS Investigation of the Distribution of K+, Na+, Mg2+ and Ca2+ Cations in Birch Pollen
Authors: Lhuissier F. , Verdus M. C. , Labulle B. , Lefebvre F. , Bocquel C. , Ripoll C. 
Published: February 2014

Abstract:Two microanalytical techniques were used to investigate the inorganic cation content and distributions in birch (Betula verrucosa Ehrh.) pollen. With intact pollen grains. X‐ray microanalysis (EDX) could only give a mean ionic composition. Secondary Ion Microscopy and Spectrometry (SIMS) appeared to be a more suitable technique to image ion distributions in the different pollen structures. This was carried out with samples prepared using a new vapour phase technique designed to improve ion retention. Transmission electron microscopy (TEM)showed good structural preservation of the samples. Monovalent ion (K+, Na+) distribution showed features different from those of the divalent cations (Ca2+, Mg2+). In the vegetative cell, the alkaline cations were mainly distributed in the most internal part of the cytoplasm and they were probably associated with starch grains or concentrated in dry vacuoles. Calcium distribution correlated well with the areas in the cytoplasm of the vegetative cell containing a dense network of mitochondria and endoplasmic reticulum. Within the pollen grain, the sperm cell appeared to contain the most calcium. Calcium was also abundant in the sporoderm. These results reveal the potential of SIMS for pollen studies that include germination, the monitoring of air pollutants and the allergens‐ion interactions.