Effects of land use on aquatic macrophyte diversity and water quality of ponds

1. Aquatic macrophyte diversity and water quality of 55 ponds in western Japan were related to land use and morphometric variables to identify the environmental factors that sustain biodiversity and the spatial extent at which these factors operate. 2. The relevant spatial extent for floating‐leaved macrophyte richness (500 m from pond edge) was larger than that for submerged macrophyte occurrence (10, 75 and 100 m), whereas emergent macrophyte richness was best explained at much larger extents (1000 m). Total macrophyte richness was explained at the extent of 500, 750 and 1000 m. The extents relevant for explaining the physicochemical condition of pond water (100 and 250 m) were similar to those for submerged and floating‐leaved macrophytes, suggesting that these two growth forms are more sensitive to water quality compared to emergent macrophytes. 3. Diversity of all three growth forms and that of total macrophytes collectively were inversely related to turbidity and nutrient concentration; among the three growth forms, submerged macrophytes were most affected by water quality. 4. Negative relationships were found between the proportion of urban area and the diversity of the three growth forms and that of total macrophytes and water quality. Species richness of emergent, floating‐leaved and total macrophytes decreased with depth and increased with surface area up to about 5000 m², above which it declined. 5. Urbanisation and enlargement of ponds were the two main factors that decreased aquatic macrophyte diversity in irrigation ponds. To alleviate the adverse effects of urban areas on aquatic macrophyte diversity, our results suggest that management efforts should focus on the creation of buffer zones within the relevant spatial extent from the pond edge.     

GENERAL PATTERN, 35SO4-INCORPORATION AND INTRACELLULAR LOCALIZATION OF GLYCANS IN DEVELOPING SEA URCHIN (ANTHOCIDARIS) EMBRYOS

Glycosaminoglycan (GAG) prepared from sea urchin embryos ( Anthocidaris crassispina ) at various stages with or without pulse ³⁵SO₄-labelling was separated into various fractions by chromatography on DEAE-cellulose with a linear NaCl concentration gradient: fraction "P" (nonacidic) and fractions "A" through "F" (of increasing acidities). The ³⁵SO₄-radioactivity was negligible in "P" and "A", largest in "B" and "C", and decreased in the other fractions three alphabetical order. During development (hatched blastulae to gastrulae) the glycans in fractions "P" and "A" decreased in amount, whereas those in "E" and "F" increased. "E" contained heparin-like (AMPS-1) and dermatanpolysulfate-like (AMPS-2) GAG in addition to a sulfated fucogalactan-like (E₁) glycan. Another sulfated fucogalactan-like (F₁) glycan was found in "F". A sulfated polysialic acid-like (S₁) glycan was found in "C". An EDTA-extract of gastrulae gave AMPS-2, E₁ and F₁. The mitochondria-rich fraction gave AMPS-1, whereas the yolk granule-rich fraction gave S₁. Most of the other still unidentified components in "B", "C", and "D" appeared to be derived from glycoproteins and were mainly located in the crude yolk-mitochondrial and cytosol fractions.     

Determination by HPLC fluorescence analysis of the natural enantiomers of sex pheromones in the New World screwworm fly, Cochliomyia hominivorax

Abstract.  Bioassays of six racemic synthesized candidate sex pheromone compounds against male New World screwworm Cochliomyia hominivorax (Coquerel) flies showed that the most potent bioactivity was found with 6-acetoxy-19-methylnonacosane and 7-acetoxy-15-methylnonacosane compared with four other isomeric acetoxy nonacosanes and a larger aliphatic ketone. As all these methyl-branched compounds have two asymmetric carbons and four possible enantiomers, characterization of the natural enantiomers was essential. All four enantiomers for the two most bioactive isomers of the natural sex pheromone were synthesized for bioassay. Hydrolysis and derivatization of these enantiomers with different fluorescent reagents was followed by column-switched high-performance liquid chromatography. The use of two linked, reversed-phase columns of different polarity held at sub-ambient temperatures allowed good separation of each enantiomer. This analysis applied to natural material was successful, as (6 R ,19 R )-6-acetoxy-19-methylnonanocosane, and (7 R ,15 R )- and (7 R ,15 S )-7-acetoxy-15-methylnonanocosane were detected in extracts of recently colonized female flies.     

Purification of Acetylcholinesterase from Sea Urchin (Hemicentrotus pulcherrimus) Embryos by Affinity Chromatography

Only one form of acetylcholinesterase (AchE) was detected in Hemicentrotus pulcherrimus embryos. In H. pulcherrimus embryos as well as in the other sea urchin embryos, AchE activity begins to increase rapidly after gastrula stage.
Purification of AchE from plutei has been carried out by the procedure including affinity chromatography. Purified AchE had the activity 14,600 times higher than that of homogenate, and the final yield of AchE was 8%. The enzyme seems to be electrophoretically homogeneous, and has a molecular weight of 3 × 10⁵ as determined by Sepharose CL–6B column chromatography.     

Morphological Alterations and Root Nodule Formation inAgrobacterium rhizogenes-mediated Transgenic Hairy Roots of Peanut (Arachis hypogaeaL.)

Transformed hairy roots were induced at the excised site ofthe epicotyl of dry mature seed of a Spanish type peanut(Arachishypogaea)cv. Java 13 2 weeks after inoculation with a wild typestrain ofAgrobacterium rhizogenes,MAFF-02-10266. Composite plantsconsisting of transformed roots with non-transformed shootswere cultured using pouches. Forty days after inoculation, thecomposite plant showed a root system with abundant root mass,more lateral branching and high fractal dimension compared tothe control. No differences were observed in production of rosette-typeroot hairs or the cross sectional structure between transformedand non-transformed roots. The inoculation ofBradyrhizobiumsp.A2R1 strain to the composite plants led to the induction oftransformed root nodules. These transformed root nodules showedproduction of leghaemoglobin in the bacterial zone and nitrogenaseactivity as assayed by C₂H₂reduction, and exhibited enlargementof the nodule cortex region andde novoroot formation from thenodule cortex.Copyright 1998 Annals of Botany Company Agrobacterium rhizogenes;Arachis hypogaeaL.; composite plant; peanut; transformation; root nodule.