Evidence for the H+-co-transport of d-alanine by the digestive glands of Dionaea muscipula Ellis

Abstract. The net uptake of ¹⁴C-D-alanine by the adaxial surfaces of the trap lobes of Dionaea muscipula Ellis (Venus's flytrap) is positively correlated with the rate of H⁺ efflux from the trap lobes. Effectors that stimulate H⁺ efflux (secretion elicitor, fusicoccin and auxin) enhance D-alanine uptake whereas effectors that inhibit H⁺ efflux (diethylstilbestrol) retard uptake. It is proposed that amino acid uptake by the digestive glands of the trap lobes proceeds via a mechanism which mediates the co-transport of H⁺ ions and amino acids. A model is presented in which a positively charged ternary complex of carrier plus amino acid plus H⁺ is transported down an inwardly directed H⁺ electrochemical potential difference generated by the secretion-elicitor-provoked discharge of HCl into the trap cavity.     

A cysteine endopeptidase ("dionain") is involved in the digestive fluid of Dionaea muscipula (Venus's fly-trap)

The carnivorous plant Dionaea muscipula (Venus's flytrap) secretes proteinases into the digestive fluid to digest prey proteins. In this study, we obtained evidence that the digestive fluid contains a cysteine endopeptidase, presumably belonging to the papain family, through inhibitor studies and partial amino acid sequencing of the major SDS-PAGE band protein. The name "dionain" is proposed for the enzyme.     

The true identity of Siderastrea glynni Budd & Guzmán, 1994, a highly endangered eastern Pacific scleractinian coral

Coral Reefs - Siderastrea glynni Budd & Guzmán, 1994 was erroneously erected from live colonies of S. siderea (Ellis & Solander, 1768) unintentionally transferred from the...     

Holocentric chromosomes may be an apomorphy of Droseraceae

Holocentric chromosomes have evolved in various plant and animal taxa, which suggests they may confer a selective advantage in certain conditions, yet their adaptive potential has scarcely been studied. One of the reasons may reside in our insufficient knowledge of the phylogenetic distribution of holocentric chromosomes across eukaryotic phylogeny. In the present study, we focused on Droseraceae, a carnivorous plant family with an unknown chromosomal structure in monotypic genera Dionaea and Aldrovanda, and a closely related monotypic family Drosophyllaceae. We used flow cytometry to detect holocentric chromosomes by measuring changes in the ratio of the number of G2 nuclei to the number of G1 nuclei in response to gamma irradiation and determined chromosomal structures in Aldrovanda vesiculosa, Dionaea muscipula, Drosera tokaiensis, and Drosera ultramafica from Droseraceae and Drosophyllum lusitanicum from Drosophyllaceae. We confirmed monocentric chromosomes in D. lusitanicum and detected holocentric chromosomes in all four Droseraceae. Our novel finding of holocentric chromosomes in monotypic genera Aldrovanda and Dionaea suggests that all Droseraceae may be holocentric, but to confirm that further research is needed due to previously reported conflicting results in Drosera rotundifolia.     

Phylogeny of the sundews, Drosera (Droseraceae), based on chloroplast rbcL and nuclear 18S ribosomal DNA Sequences

The sundew genus Drosera consists of carnivorous plants with active flypaper traps and includes nearly 150 species distributed mainly in Australia, Africa, and South America, with some Northern Hemisphere species. In addition to confused intrageneric classification of Drosera, the intergeneric relationships among the Drosera and two other genera in the Droseraceae with snap traps, Dionaea and Aldrovanda, are problematic. We conducted phylogenetic analyses of DNA sequences of the chloroplast rbcL gene for 59 species of Drosera, covering all sections except one. These analyses revealed that five of 11 sections, including three monotypic sections, are polyphyletic. Combined rbcL and 18S rDNA sequence data were used to infer phylogenetic relationships among Drosera, Dionaea, and Aldrovanda. This analysis revealed that all Drosera species form a clade sister to a clade including Dionaea and Aldrovanda, suggesting that the snap traps of Aldrovanda and Dionaea are homologous despite their morphological differences. MacClade reconstructions indicated that multiple episodes of aneuploidy occurred in a clade that includes mainly Australian species, while the chromosome numbers in the other clades are not as variable. Drosera regia, which is native to South Africa, and most species native to Australia, were clustered basally, suggesting that Drosera originated in Africa or Australia. The rbcL tree indicates that Australian species expanded their distribution to South America and then to Africa. Expansion of distribution to the Northern Hemisphere from the Southern Hemispere occurred in a few different lineages.     

Droseraceae germination patterns and their taxonomic significance

The Droseraceae exhibit a range of"germination patterns which are of possible taxonomic usefulness at the sectional and higher levels. Three patterns were observed in the family: phanerocotylar ( Drosera subgen. Drosera and Regia ); cryptocotylar (subgen. Ergaleium and Rorella ); and a new category, hemi-cryptocotylar, where both cotyledon apices remain in the seed coat, but the remainder emerges forming a photosynthetic cotyledon loop ( Dionaea, Drosophyllum and Drosera adelae ). Subgenus Drosera , especially sect. Drosera , is heterogenous for germination, and other features, with Drosera indica , sect. Lasiocephala and D. neocaledonica anomalous on current placements, and in need of further study. Conversely, the merger of sects Psycophila and Stelogyne and subgenl Ptycnostigma with subgen. Drosera sect. Drosera is supported by their germination features. Further studies are needed to determine the significance of environmental effects on the germination characteristics, although because the results of this study largely agree with recent morphological and molecular studies, this suggests that germination characteristics are useful at the sectional level, potentially providing additional characters for phylogenetic investigations within the Droseraceae.     

A muscle contracting substance from a plant's closing Fly-Trap

Summary A muscle contracting substance (MCS) occurs in crushed, incubated traps of the insectivorous plant, the Venus Fly-Trap (Dionaea muscipula Ellis). This MCS is provisionally identified as lysophosphatidic acid. More MCS is produced from traps which have been touched than from untouched traps, which may be due to activation of phospholipase D. This enzyme hydrolyses phospholipids of membranes, and could alter the physiological properties of membranes.Abbreviations MCS muscle contracting substance - ACh acetylcholine     

The biochemical composition of the cement of a pedunculate cirripede

The composition of the cement of Lepas fascicularis Ellis & Solander in terms of carbohydrate, lipid, and amino-acid composition of the protein has been determined: in this species the cement acts as a float. The major constituent is protein. The lipid content lies between that given for Balanus spp. while the protein contains a larger proportion of glutamic acid and smaller proportions of lysine and histidine.     

Gametogenesis in placental and non-placental ovicellate cheilostome Bryozoa

Oogenesis is compared in two cheilostome bryozoans with contrasting reproductive strategies. from southern Britain: Chartella papyracea (Ellis & Solander) is a non–placental ovicellate brooder, whereas Bugula flabellata (Thompson in Gray) is a placental brooder. The ovarian cycles are similar, and each oocyte develops in tandem with a single nurse cell. Eggs of both species are telolecithal, However, those of B. flabellata are less than 20% the volume of those of the other species, and there are considerable differences in the ultra-structure of oogenesis. In both cases, spermatogenesis has the typical bryozoan pattern. Precocious insemination of the oocyte occurs in both species.     

Low salinity induces reversible tissue regression in the estuarine sponge Microciona prolifera (Ellis & Solander)

Explants of Microciona prolifera (Ellis & Solander) maintained in laboratory culture at either 20‰ or 15‰ salinity retained a normal tissue organization. Expiants gradually transferred to 10‰ underwent tissue regression during which flagellated chambers, canals, subdermal spaces and oscula disappeared. When the expiants were gradually returned to 20‰ these structures redeveloped. Reproductive activity in the expiants appeared to be normal at 20‰, somewhat slowed at 15‰, and inhibited at 10‰.     

Biologically Closed Electrical Circuits in Venus Flytrap

The Venus flytrap (Dionaea muscipula Ellis) is a marvel of plant electrical, mechanical, and biochemical engineering. The rapid closure of the Venus flytrap upper leaf in about 0.1 s is one of the fastest movements in the plant kingdom. We found earlier that the electrical stimulus between a midrib and a lobe closes the Venus flytrap upper leaf without mechanical stimulation of trigger hairs. The Venus flytrap can accumulate small subthreshold charges and, when the threshold value is reached, the trap closes. Here, we investigated the electrical properties of the upper leaf of the Venus flytrap and proposed the equivalent electrical circuit in agreement with the experimental data.     

Trap diversity and evolution in the family Droseraceae

We review trapping mechanisms in the carnivorous flowering plant family Droseraceae (order Caryophyllales). Its members are generally known to attract, capture, retain and digest prey animals (mainly arthropods) with active snap-traps (Aldrovanda, Dionaea) or with active sticky flypaper traps (Drosera) and to absorb the resulting nutrients. Recent investigations revealed how the snap-traps of Aldrovanda vesiculosa (waterwheel plant) and Dionaea muscipula (Venus’ flytrap) work mechanically and how these apparently similar devices differ as to their functional morphology and shutting mechanics. The Sundews (Drosera spp.) are generally known to possess leaves covered with glue-tentacles that both can bend toward and around stuck prey. Recently, it was shown that there exists in this genus a higher diversity of different tentacle types and trap configurations than previously known which presumably reflect adaptations to different prey spectra. Based on these recent findings, we finally comment on possible ways for intrafamiliar trap evolution.     

Phenotypic plasticity in the reef corals Montastraea annularis (Ellis & Solander) and Siderastrea siderea (Ellis & Solander)

Mature colonies of Montastraea annularis (Ellis & Solander) and Siderastrea siderea (Ellis & Solander) were transplanted reciprocally between four reef environments near Discovery Bay, Jamaica. Multivariate analyses of variables describing corallite structures show that colonies of M. annularis change their skeletal morphology after transplantation from that characteristic of their original habitat to that characteristic of the environment to which they were moved. Control colonies of M. annularis, however, retain the morphology characteristic of their original habitat after manipulation. Many colonies of S. siderea similarly altered their morphology after transplantation, but some retained the morphology characteristic of their original habitat. Most control colonies of S. siderea did not change after manipulation. In general, control colonies of S. siderea show more morphologic variation between skeleton deposited before and after manipulation within colonies and also between colonies within populations, than did control colonies of M. annularis.These results indicate that, although M. annularis shows more plasticity than S. siderea. both species have highly plastic phenotypes. A large number of characters describing the architecture of corallites respond to environmental factors such as light intensity, sedimentation rate, water activity, and food availability. The most plastic characters in M. annularis describe coenosteal features and the thickness of thecae. The most plastic characters in S. siderea describe the thicknesses of thecae. septa, and columellae.This study suggests that phenotypic plasticity is an important species attribute in scieractinians and may be a significant mechanism in controlling the distribution and abundance of scleractinians on reefs.     

The effect of density and mutual interference by a Predator: A laboratory study of predation by the Nudibranch Coryphella rufibranchialis on the hydroid Tubularia larynx

The nudibranch Coryphella rufibranchialis (JOHNSTON) feeds on a variety of hydroids, including Tubularia larynx Ellis & Solander. Experiments in which density of prey and predators were altered showed that more prey were eaten as prey density increased. However, more prey were consumed at low predator densities, presumably because of mutual interference among nudibranchs at the higher predator densities. The number of prey consumed per nudibranch was maximal with low predator densities and a ratio of 25–50 polyps per predator. Coryphella seems to show an opportunistic feeding strategy involving solitary predators rapidly depleting hydroid colonies and moving on to new colonies.     

The biology of the marine sponge Microciona prolifera (Ellis and Solander). III. Spicule secretion and the effect of temperature on spicule size

The secretion of siliceous spicules in the marine demosponge Microciona prolifera (Ellis and Solander) is by three different means. Styles are secreted by sclerocytes with archeocyte characteristics (nucleolate nucleus, phagosomes). chelas are formed by small sclerocytes with anucleolate nuclei, and toxas are apparently formed extracellularly within membranous material. Genetically and physiologically equivalent explants of this sponge were grown at 15, 20, and 25 C for four weeks. Analyses of spicule dimensions show little correlation of temperature with spicule length, except in the case of toxas. but a clear inverse relationship of spicule width with temperature. It is suggested that thicker spicules are formed at lower temperatures due to the more efficient entrapment of silicon rather than to effects upon silicon transport. Chela dimensions are very uniform implying an all or none process in their secretion. Differences in spicule dimensions between individual sponges grown at these temperatures may be due to the highly complex pathways of silicon transport and/or to genetic differences.     

Comparative phosphate acquisition in giant-celled rhizophytic algae (Bryopsidales, Chlorophyta): Fleshy vs. calcified forms

Phosphate uptake through above-ground thalli vs. subterranean rhizoids has been compared in siphonaceous rhizophytic green algal species from five globally distributed tropical genera: Avrainvillea nigricans Decaisne, Caulerpa lanuginosa J. Agardh, Halimeda incrassata (J. Ellis) J.V. Lamouroux, Penicillus capitatus Lamarck, and Udotea flabellum (J. Ellis & Solander) M. Howe. Plants were collected, acclimated to lab conditions for 3 days, and then incubated for 8 h at saturating light intensity with 30 μM PO₄³⁻ added to their above-ground thallus or below-ground rhizoids. Percent tissue phosphorus was then compared to control specimens, which were run simultaneously in the absence of phosphate. The two fleshy species, A. nigricans and C. lanuginosa, showed no significant differences in tissue nutrient status, and displayed much larger variation among controls than the three calcified species. Calcified species showed greater phosphorus content after being exposed to either above- or below-ground thallus portions, indicating that these seaweeds can respond to short term increases in nutrient availability and have a more regulated nutrient acquisition mechanism. Results suggest that calcification may play an important role in phosphorus absorption.     

Quantification of insect nitrogen utilization by the venus fly trap Dionaea muscipula catching prey with highly variable isotope signatures.

Dionaea is a highly specialized carnivorous plant species with a unique mechanism for insect capture. The leaf is converted into an osmotically driven trap that closes when an insect triggers sensory trichomes. This study investigates the significance of insect capture for growth of Dionaea at different successional stages after a fire, under conditions where the prey is highly variable in its isotope signature. The contribution of insect-derived nitrogen (N) was estimated using the natural abundance of 15N. In contrast to previous 15N studies on carnivorous plants, the problem emerges that delta15N values of prey insects ranged between -4.47 per thousand (grasshoppers) and +7.21 per thousand (ants), a range that exceeds the delta15N values of non carnivorous reference plants (-4.2 per thousand) and soils (+3 per thousand). Thus, the isotope-mixing model used by Shearer and Kohl to estimate the amount of insect-derived N is not applicable. In a novel approach, the relationships of delta15N values of different organs with delta15N of trapping leaves were used to estimate N partitioning within the plant. It is estimated that soon after fire approximately 75% of the nitrogen is obtained from insects, regardless of plant size or developmental stage. The estimates are verified by calculating the average isotope signatures of insects from an isotope mass balance and comparing this with the average measured delta15N values of insects. It appears that for Dionaea to survive and reach the flowering stage, seedlings must first reach the 6th-leaf rosette stage, in which trap surface area nearly doubles and facilitates the capture of large insects. Large amounts of nitrogen thus made available to plants may facilitate an enhanced growth rate and the progressive production of additional large traps. Dionaea reaches a maximum abundance after fire when growth of the competing vegetation is suppressed. About 10 years after fire, when grasses and shrubs recover, Dionaea becomes overtopped by other species. This would not only reduce carbon assimilation but also the probability of catching larger prey. The amount of insect-derived nitrogen decreases to 46%, and Dionaea becomes increasingly dependent on N-supply from the soil. Competition for both light and N may cause the near disappearance of Dionaea in older stages of the fire succession.     

Receptor Response in Venus''s Fly-Trap

The insect-trapping movement of the plant Dionaea muscipula (Venus's fly-trap) is mediated by the stimulation of mechanosensory hairs located on the surface of the trap. It is known that stimulation of the hairs is followed by action potentials which are propagated over the surface of the trap. It has been reported that action potentials always precede trap closure. The occurrence of non-propagated receptor potentials is reported here. Receptor potentials always precede the action potentials. The receptor potential appears to couple the mechanical stimulation step to the action potential step of the preying sequence. Receptor potentials elicited by mechanical stimulation of a sensory hair were measured by using the hair as an integral part of the current-measuring path. The tip of the hair was cut off exposing the medullary tissue; this provided a natural extension of the measuring electrode into the receptor region at the base of the hair. A measuring pipette electrode was slipped over the cut tip of the hair. Positive and negative receptor potentials were measured. Evidence is presented which supports the hypothesis that the positive and negative receptor potentials originate from independent sources. An analysis is made of (a) the relation of the parameters of mechanical stimuli to the magnitude of the receptor potential, and (b) the relation of the receptor potentials to the action potential. The hypothesis that the positive receptor potential is the generator of the action potential is consistent with these data.     

Extracting and purifying R-phycoerythrin from Mediterranean red algae Corallina elongata Ellis & Solander

R-Phycoerythrin (R-PE) is a protein acting as a photosynthetic accessory pigment in red algae (Rodophyta). This protein has gained importance in many biotechnological applications in food science, immunodiagnostic, therapy, cosmetics, protein and cell labelling, and analytical processes. In this paper we report on a new, one step procedure for the extraction and purification of R-PE from a new source: the Mediterranean red algae Corallina elongata Ellis & Solander. This red algae contains mainly R-PE and is suitable for the production in culture. No other contaminating phycobiliproteins could be detected in the extracts. The method we propose for the purification is based on the use of hydroxyapatite, a chromatographic resin that can be produced in the laboratory at very low cost and can be used batch-wise with large amounts of extracts, alternative to chromatography, and therefore can be scaled up. Both the yield and the purity of R-PE are very good.