Kimon T. Bird

Agar yield, quality and standing crop biomass of Gelidium serrulatum, Gelidium floridanum and Pterocladia capillacea in Venezuela

Abstract Venezuela and the nearby islands have natural resources of three agarophyte species in the Gelidiales: Gelidium serrulatum, Gelidium floridanum and Pterocladia capillacea. Standing crop biomass for two of these species, G.serrulatum and P.capillacea, varies between 1.4–0.5 and kg dry wt/m2. The agar yield from G.serrulatum and G.floridanum ranges from 12 to 34%, depending on the method of extraction. Agar extraction of both species directly into 0.25 N NaOH provided significantly higher gel strengths (>1100 g/cm2) than either extraction in water or using an alkali pretreatment process of 1.0 N NaOH. Direct extraction of agar in 0.25 N NaOH led to an improvement of gel strength by almost three times that of extraction in water for G.serrulatum. Agar extractions from P. capillacea showed yields ranging from 12 to 32% (depending on extraction process) and gel strengths were highest in the samples extracted after pretreatment in 1.0 N NaOH. In all cases treatment with alkali led to a reduction in percent sulfate of agar and an increase in 3, 6-anhydrogalactose. Both chemical analyses and 13C NMR indicate that the agars from G.serrulatum and G.floridanum are pyruvated. This pyruvated agar did not partition out into different hydrophilic and hydrophobic fractions based on sequential ethanol extraction of G.serrulatum. The agar quality, yields and biomass data suggest that Venezuela could provide commercial quantities of these important agarophytes.

Agglutinins from marine macroalgae of the southeastern United States

Protein extracts from 22 species of marine macroalgae from Florida and North Carolina were compared for their abilities to agglutinate sheep and rabbit erythrocytes. Protein extracts from 21 algal species agglutinated rabbit erythrocytes compared to 19 for sheep erythrocytes. However, agglutination by brown algal extracts was variable. The agglutination produced by protein extracts from Dictyota dichotoma could be blocked by addition of polyvinylpyrrolidone. Protein extracts from North Carolina macroalgae were also tested against five bacterial species. Three of these agglutinated bacterial cells. Ulva curvata and Bryopsis plumosa agglutinated all five species. Protein extracts from five species of Florida algae were tested for their effects on mitogenesis in mouse splenocytes and human lymphocytes. Gracilaria tikvahiae HBOI Strain G-5, Ulva rigida and Gracilaria verrucosa HBOI Strain G-16S stimulated mitogenesis in mouse splenocytes, while Gracilaria tikvahiae HBOI Strain G-16stimulated mitogenesis in human lymphocytes.

Karyology and agar analysis of the agarophyteGelidiella acerosa (Forsskål) Feldmannet Hamel from the Philippines

Microspectrophotometry with the DNA-localizing fluorochrome DAPI demonstrated ploidy level differences in tetrasporophytic and presumptive gametophytic phases ofGelidiella acerosa from the Philippines. Comparison of mean nuclear DNA (If) values to chicken erythrocytes (RBC) resulted in an estimate of 0.32 pg/2 C genome. Karyological studies with aceto-orcein revealed a chromosome complement of six bivalents during diakinesis of tetrasporocytes. The agar yield ranges from 13–24% dry weight, depending on the method of extraction. Agar extraction in 1 N NaOH resulted in an increased gel strength of 189 g cm−2 at 1.5% concentration. Infrared spectroscopy indicated a relatively high sulfate content in native agar. The low (61 °) melting temperature is indicative of high sulfation and small molecular size.

Flowering and genetic banding patterns of Halophila johnsonii and conspecifics

Abstract Halophila johnsonii Eiseman is a seagrass that is restricted in distribution to the Indian River of Florida from Sebastian Inlet on the north to Biscayne Bay on the south, and currently is being considered for listing as a rare/endangered species by the National Marine Fisheries Service (NMFS). At the time it was described as a new species in 1980, no staminate flowers had been reported. After numerous searches in the Indian River in the late 1980s and early 1990s and after culture in the laboratory, only pistillate flowers are known. DNA testing indicates that H. johnsonii is distinct from H. decipiens Ostenfeld. Isozymes and sulfated flavonoids had suggested earlier that H. johnsonii may be closely related to the small-leafed plants in H. minor (Zoll.) den Hartog complex that are widely distributed in the Indo-Pacific. H. johnsonii may represent the vegetative development of a single pistillate clone.

Effects of environmental factors on carrageenan fromGymnogongrus griffithsiae (Gigartinales, Rhodophyta)

The effects of environmental factors on substratum coverage, thallus length, production of iota carrageenan and gelling behavior were investigated in field populations of the red algaGymnogongrus griffithsiae (Turner) Martius. Irradiance and water temperature affected thallus substratum coverage and water gel strength of the carrageenan. The significant monthly differences in thallus length, carrageenan content and carrageenan gelling properties were not attributable to seasonal variations in irradiance and water temperature. The effect of temperature and N loading on biomass productivity, carrageenan yield and gelling characteristics were also investigated using cultures. N-enriched cultures showed decreased gel yields, higher viscosities and higher water gel strengths in the carrageenans extracted from these cultures. Milk reactivity tests were correlated with thallus nitrogen and water dessert gel strength, but neither culture temperature nor N loading showed a significant effect. The field and culture studies indicate how temperature, irradiance and N availability affect growth and hydrocolloid production.

Nuclear genome characterization and carrageenan analysis ofGymnogongrus griffithsiae (Rhodophyta) from North Carolina

DNA reassociation kinetics were used to determine nuclear genome organization and complexity inGymnogongrus griffithsiae (Gigartinales, Rhodophyta). Results indicate the presence of three second order components corresponding to fast (3%), intermediate (8%) and slow (89%) fractions. Thus the genome consists mainly of unique sequences. Thermal denaturation (Tm) indicated a nuclear DNA base pair composition of 40 mol% G + C. Microspectrophotometry with the DNA-localizing fluorochrome DAPI was used to confirm ploidy level differences in the gametophytic and tetrasporoblastic phases. Comparisons of mean nuclear DNA (If) values to chicken erythrocytes (RBC) resulted in an estimate of 0.32 pg/2 C genome forGymnogongrus griffithsiae. Karyological studies using aceto-orcein revealed the presence of ca. 23 bivalents during diakinesis of tetrasporangial mother cells. Total carrageenan content in water extraction was 30% dry weight. Infrared spectroscopy confirmed the isolated carrageenan to be the iota-fraction.

Gracilaria tikvahiae agglutinin. Partial purification and preliminary characterization of its carbohydrate specificity

A potent agglutinin of rabbit and sheep red blood cells, obtained from the red alga Gracilaria tikvahiae, was purified by ammonium sulfate fractionation, ion exchange, gel filtration, and hydroxylapatite chromatography. Human A and B blood group erythrocytes were also agglutinated, whereas human O blood group erythrocytes were not agglutinated. The hemagglutination titer was not significantly affected by the addition of EDTA or the divalent cations Ca2+, Mg2+, or Mn2+. The carbohydrate specificity was characterized by hemagglutination inhibition using various monosaccharides, glycoproteins, and glycopeptides. The results suggested that the agglutinin has affinity for N-acetylneuraminic acid as well as glycoconjugates containing N-acetylneuraminic acid.

Quantification and characterization of nuclear genomes in commercial red seaweeds (Gracilariales) from the Philippines

Eight species of Gracilariaceae from the Philippines, representing the generaGracilaria, Gracilariopsis andHydropuntia, were investigated to quantify and characterize their nuclear genomes. DNA reassociation kinetics were used to determine nuclear genome organization and complexity in six of these species. Results indicate the presence of three second order components corresponding to fast, intermediate and slow fractions. Repetitive sequences varied from 13–74% and unique DNA ranged from 26–84%. Microspectrophotometry with the DNA-localizing fluorochrome DAPI was used to quantify nuclear DNA contents. Comparisons of mean nuclear DNA (If) values to chicken erythrocytes (RBC) resulted in an estimate of 0.38–0.43 pg/2 C genomes for seven of the species investigated. Preliminary analyses of agar content and quality confirm the economic potential ofGracilaria firma, Gracilaria sp. 2 from Sorsogon andGracilariopsis bailinae. Nuclear genome profiles developed from data for genome size, organization and complexity are compared with data for agar quantity and quality. Gel quality and quantity do not appear to be correlated with either large repetitive fraction DNA or a high degree of genome complexity.

Physiological responses of transplanted populations of Sargassum pteropleuron Grunow in Florida

Abstract Three populations of Sargassum pteropleuron Grunow were transplanted among sites on the Florida east and west coasts and Florida Keys. Significant increases in length and weight occurred at all three sites, with maximum growth rates of 0.08 doublings day −1 , and survival of 35–100%. Transplants showed an increase in irradiance-photosynthesis rates with regards to I c and α when compared to the initial plants if transplanted to sites with higher turbidity, while transplants to clear water sites indicated decreases. All populations had broad tolerances to 12 combinations of salinity and temperature, prior to and after transplantation studies. Acclimation to new sites did not result in significant changes in proximate composition (ash, protein, carbohydrate, lipid, fiber and alginate). The species was found to have broad physiological tolerances, allowing for acclimation at sites of markedly different characteristics.

Evidence of 4-O-methyl-α-L-galactose in the agar ofGracilaria verrucosa strain G-16

We recently published several studies regarding the role of environmental factors on agar quality and chemistry from Gracilaria verrucosa (tentative species identification) Strain G-16 (Bird, 1988, Bird etal., 1989; Chiles etal., 1989). Despite observing a high gelling temperature (42-53 °C), we reported that we did not observe any evidence of C2 or C6 methylation based on 3C NMR. Since then, it has been suggested that the spectra provided evidence of C4 methylation of the galactose repeating unit (Lahaye, personnel communication). Lahaye etal. (1988) and Karamanos et al. (1989) have published assignments for 4-0methyl-L-galactose in the agar from Gracilaria verrucosa, and suggested that it represents a side group linked to 0-6 of the 3-0-linked galactopyranose units in agar. A re-examination of our spectral data suggests that assignments for agar from Gracilaria verrucosa Strain G-16 are similar to those of Lahaye etal. (1988) and Karamanos etal. (1989). In alkali-modified agars from plants grown in 8 different culture environments, there are discernable shifts at 98.4, 79.4, 72.6, 70.7 and 69.5 ppm, corresponding to C 1, C4, C5, C3 of the galactose repeating unit and C6 of the anhydrogalactose repeating unit, respectively. There is also a shift at 61.8 ppm, corresponding to the C4 methylation. However, our alkali-modified agars showed either a negligible or barely discernable shift at 59.1 ppm, which corresponds to the C6 methylation. Evidence for C6 methylation is not apparent until NMR data are examined from agars extracted based on their solubility in decreasing concentrations of hot alcohol in water (Chiles et al., 1989). It appears that agar from Gracilaria verrucosa Strain G-16 has some 4-0-methylgalactose branching side groups, but probably only minimal amounts of C6 methylation. This suggestion is especially supported by a comparison of the extremely weak shifts at 59.1 for C6 methylation compared to those at 61.8 for C4 methylation (Bird et al., 1989; Chiles et al., 1989).