R-phycoerythrin from the macroalgaCorallina officinalis (Rhodophyceae) and application of a derived phycofluor probe for detecting sugar-binding sites on cell membranes

R-Phycoerythrin (absorption spectrum 280; 495;sh 535, 564 nm with A564/A280 ratio of 5.3) was purified from the red macroalgaCorallina officinalis. The relative molecular mass determined from PAGE was 240 000. SDS-PAGE demonstrated two major subunits ofM _r 20 000 and 21 000, respectively, and a minor subunit ofM _r 30 000. A fucospyranosyl phenylisothiocyanate conjugate was prepared and this novel fluorescent affinity reagent used in conjunction with a flow cytometer to probe fucose-binding sites on blood mononuclear cells. By varying the sugar and using other phycobiliproteins the approach has the potential for simultaneously monitoring different sugar binding sites on subsets of cells within populations.     

Shigeo Yamanouchi (1876–1973): A noted Japanese phycologist

Dr Shigeo Yamanouchi was born in Yamagata Prefecture and completed his secondary education at Tokyo Higher Normal School (THNS) where he was also a professor until 1904. In 1905, he went to the University of Chicago in the USA and earned a PhD in Botany in 1907. He is best noted for his excellent research on the cytology and life histories of the marine algae Polysiphonia, Fucus, Cutleria, Aglaozonia and Zanardinia, published between 1906 and 1921 while he was associated with the University of Chicago. He also described the freshwater green alga Hydrodictyon africanum. In 1910, he returned to THNS as a Professor and wrote several botanical textbooks, receiving his DSc degree in 1911 and traveling in England and the USA as an advisor for the Japanese Ministry of Education during 1911–1913. For much of the time between 1920 and 1942 he remained in the USA, returning to Japan following the advent of World War II, During his later life, he was in obscurity, and sadly there is very little recorded of his activities in the post-war years. He died in Tokyo on 2 February 1973 at the age of 96.     

The dodecameric vanadium-dependent haloperoxidase from the marine algae Corallina officinalis: cloning, expression, and refolding of the recombinant enzyme

The dodecameric vanadium-dependent bromoperoxidase from Corallina officinalis has been cloned and over-expressed in Escherichia coli. However, the enzyme was found to be predominantly in the form of inclusion bodies. This protein presents a challenging target for refolding, both due to the size (768 kDa) and quaternary structure (12 × 64 kDa). Successful refolding conditions have been established which result in an increase in the final yield of active bromoperoxidase from 0.5 mg to 40 mg per litre of culture. The refolded protein has been characterised and compared to the native enzyme and was shown to be stable at temperatures of 80 °C, over a pH range 5.5–10 and in organic solvents such as ethanol, acetonitrile, methanol, and acetone. The novel refolding approach reported in this paper opens up the full potential of this versatile enzyme for use in large scale biotransformation studies.     

PHYLOGENETIC RELATIONSHIPS WITHIN THE GENUS HYPNEA (GIGARTINALES,RHODOPHYTA), WITH A DESCRIPTION OF H. CAESPITOSA SP. NOV.1

Species discrimination within the gigartinalean red algal genus Hypnea has been controversial. To help resolve the controversy and explore phylogeny within the genus, we determined rbcL sequences from 30 specimens of 23 species within the genus, cox1 from 22 specimens of 10 species, and psaA from 16 species. We describe H. caespitosa as a new species characterized by a relatively slender main axis; a pulvinate growth habit with entangled, anastomosing, and subulate uppermost branches; and unilaterally borne tetrasporangial sori. The new species occurs in the warm waters of Malaysia, the Philippines, and Singapore. The phylogenetic trees of rbcL, psaA, and cox1 sequences showed a distant relationship of H. caespitosa to H. pannosa J. Agardh from Baja California and the marked differentiation from other similar species. The rbcL + psaA tree supported monophyly of the genus with high bootstrap values and posterior probabilities. The analysis revealed three clades within the genus, corresponding to three sections, namely, Virgatae, Spinuligerae, and Pulvinatae first recognized by J. G. Agardh. Exceptions were H. japonica T. Tanaka in Pulvinatae and H. spinella (C. Agardh) Kütz. in Spinuligerae.     

The role of seed limitation and resource availability in the recruitment of native perennial grasses and exotics in a South Australian grassland

Abstract We investigated what factors lead to invasion of exotics or re‐colonization of native perennial grasses in the South Australian mid‐north grasslands. We manipulated 160 experimental quadrats by clipping, irrigation and seed addition and assessed recruitment by exotics in an area dominated by perennial grasses and perennial grass recruitment in an area dominated by exotics. Treatment effects differed with season for exotics: their biomass increased with irrigation in autumn and seed addition in winter. However, in both periods other factors, probably soil properties, also had a strong effect. We detected no perennial grass seedlings in the quadrats over 1 year, possibly due to unsuitable environmental conditions or persistent high competition levels. Under controlled conditions the presence of the invasive annual Avena barbata had a strong negative effect on the recruitment of the native perennial Austrodanthonia caespitosa at any moisture and nutrient availability. Avena also germinated faster and more frequently than Austrodanthonia, especially at low soil moisture. During an imposed drought Austrodanthonia seedlings survived longer in the absence of Avena. The results suggest that annual exotics are highly responsive to resources and can quickly invade areas, while the re‐colonization of invaded areas by native grasses requires a complex (and less likely) rainfall regime.     

A comparison of the north-and southe european associations of Corallina officinalis L.

A comparison betweenCorallina officinalis associations from the northern Adriatic and the Icelandic coastal area is given regarding their floristic composition, zonal position and physionomy, as related to the environmental parameters and the different origins of the respective floras.     

Effects of spatial aggregation on competition,complementarity and resource use

Abstract The spatial distributions of most species are aggregated to varying degrees. A limited number of studies have examined the effects of spatial aggregation on interspecific and intraspecific interactions, generally finding that spatial aggregation can enhance coexistence between species by reducing the capacity for interspecific competition. Less well studied are the effects of spatial aggregation on complementarity (i.e. differences in resource use strategies) and resource use. Our primary hypothesis was that spatial aggregation reduces the complementarity between species owing to: (i) less interspecific interactions as a result of spatial separation; and (ii) less differences between species as a result of phenotypic plasticity. We further postulate that these negative effects of spatial aggregation on complementarity will reduce resource use by the community. Here we test these hypotheses in a pot experiment in which we applied three levels of spatial aggregation to three sets of two‐species mixtures of herbaceous perennial plant species from native grasslands of south‐eastern Australia. Both root and shoot biomass were significantly affected by spatial aggregation, although the nature of these affects depended upon the species involved, and the relative strengths of interspecific versus intraspecific competition. Complementarity between species in the distribution of their green leaves decreased significantly as spatial aggregation increased for one of the species mixtures, providing some evidence in support of our hypothesis that aggregation reduces complementarity through phenotypic plasticity. Spatial aggregation also altered light interception and use of soil moisture resources, although these effects were dependent on the species involved. We suggest that clear effects of spatial aggregation on complementarity and resource use may be obscured by the idiosyncratic way in which neighbour identity influences plant growth and hence plant size, limiting the ability to generalize, at the community level, any underlying effects of spatial pattern on ecological process.     

Activities of Corallina (Corallinales) and other Rhodophyta polymers in the modulation of calcification

The effects of a range of fractions from calcareous and non-calcareous marine red algae on the crystal growth of calcite-seeded supersaturated calcium carbonate solutions were monitored by measuring the change in conductivity. An effective inhibitor of crystallization was a macromolecular fraction derived from the coralline red alga, Corallina officinalis, by a series of acid and alkali treatments. A preliminary characterization of the extract suggests the presence of a protein-polysaccharide complex. The possibility that this participates in the modulation of calcification in vivo is suggested.