Seasonal Variations in Agar Yields and Quality from North Carolina Agarophytes

Bird, Kimon T.; Hinson, T. K.

doi:10.1515/botm.1992.35.4.291

Cited by 37 publications

(27 citation statements)

References 11 publications

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“…The aim of the present study was to examine the effect of NH,+ availability on N assimilation in Gracilariopsis lemaneiformis, a n agarophyte red alga of potential use in aquaculture (Bird & Hinson 1993).…”

Section: Introductionmentioning

confidence: 99%

Nitrogen assimilation following NH4+ pulses in the red alga Gracilariopsis lemaneiformis:effect on C metabolism

Jj¹,

Kt²,

Fx³

1995

Mar. Ecol. Prog. Ser.

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Nitrogen assimilation following NH4+ pulses in the red alga Gracilariopsis lemaneiformis: effect on C metabolism Juan J. V e r g a r a l , Kimon T. ~i r d~, F. X. ~i e l l~ ABSTRACT: The short-term effect of external NH,' availability on N assimilation, as well as on C metabolism, has been studied in the red alga Gracilariopsis lemaneiformis. This agarophyte seaweed showed a high capacity to take up external NH,' and to channel it toward proteins. As in a previous study in Corallina elongata, it appears that N limitation redirected the flow of internal N toward nonpigmented proteins, whereas phycobiliprotein synthesis was preferentially stimulated with respect to other proteins in response to external NH,+ pulses. A possible mechanism by which chloroplastic protein synthesis is limited by external N availability more than cytosolic proteins could be involved. In relation to C metabolism, insoluble and soluble carbohydrates were mobilized in response to NH,+ assimilation at a non-saturating irradiance for photosynthesls of 80 pm01 m-2 S-'. The main change in C metabolism was not seen for total C. The principal effect was the flow of C among different compounds, from carbohydrates to organic N compounds (amino acids and prote~ns) during transient NH, + assimilation.

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Section: Introductionmentioning

confidence: 99%

Nitrogen assimilation following NH4+ pulses in the red alga Gracilariopsis lemaneiformis:effect on C metabolism

Jj¹,

Kt²,

Fx³

1995

Mar. Ecol. Prog. Ser.

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“…The three species with the lowest agar yields were collected during July, when temperatures can exceed 30 0 C. Gracilaria caudata was collected in December, when temperatures are much cooler. Bird (1988) (Table 5), but they still are low when compared with commercial agarophytes (Bird & Hinson, 1992). Previous comparisons of genome organization and complexity data with information for gel quality suggested a possible correlation between genome profiles and synthesis of commercial-grade agars in species of the Gracilariales (Dutcher et al, 1990;Kapraun et al, 1993b).…”

Section: Agar Characterizationmentioning

confidence: 97%

“…Detailed procedures for agar extraction following alkaline pretreatment in 1.0 N NaOH have been specified previously (Bird & Hinson, 1992). All extractions were performed using triplicate samples.…”

Section: Agar Extraction and Analysismentioning

confidence: 99%

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Agar Analysis, nuclear genome quantification and characterization of four agarophytes (Gracilaria) from the Mexican Gulf Coast

Lopez-Bautista

Kapraun

1995

J Appl Phycol

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DNA reassociation kinetics were used to determine nuclear genome organization and complexity in four species of Gracilaria (Gracilariales, Rhodophyta). In Gracilaria tikvahiae, G. caudata, G. cervicornis and G. divaricata, results indicate the presence of three second order components corresponding to fast, intermediate and slow fractions. Repetitive sequences varied from 13-46% and unique DNA ranged from 45-78%. Thermal denaturation (T,) indicated guanine + cytosine (G + C) levels of 41.9-46.0 mol % G + C. Microspectrophotometry with the DNA-localizing fluorochrome DAPI was used to quantify nuclear DNA content. Comparisons of mean nuclear DNA (If) values to chicken erythrocytes (RBC) resulted in an estimate of 0.37-0.40 pg/2C genomes for the four Gracilaria species. Total agar content following alkaline pretreatment ranged from 7-15% dry weight. Gel strengths were generally below commercial levels, ranging from 40-260 g cm -2 . Nuclear genome profiles developed from information 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 as previously speculated.

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“…Agar from many species of Gracilaria and Gracilariopsis has been studied for properties and structure by chemical, enzymatic, and spectroscopic methods (Duckworth et al, 1971;Bird & Hinson, 1992;Hurtado-Ponce, 1992). Gracilariopsis lemaneiformis, newly reported from Japan, is widely distributed in Tosa Bay, south Ise Bay, and other Japanese inland seas (Chirapart et al, 1994a).…”

Section: Introductionmentioning

confidence: 99%

Chemical composition of agars from a newly reported Japanese agarophyte, Gracilariopsis lemaneiformis

et al. 1995

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The chemical composition of agars from Gracilariopsis lemaneiformis, newly reported from Japan, was investigated. Native agars were isolated by a sequential extraction of plants in water at 22 °C and 100 °C, and in boiling 20, 40 and 60% ethanol. Agars in each extract were analyzed by chemical methods, H, 3 C NMR; and IR spectroscopy. The highest yield of agar (total carbohydrate) was obtained from the 40% ethanol extract (55%). Highest sulfate content was attained in non-alkali treated agars extracted with hot water (4.81 %, DS 0.2). The 3,6-anhydrogalactose content was highest in the 40% ethanol extract (36.1% in non-alkali treatment, 40.3% in alkali treatment). The highest methoxyl content (6.51%, DS 0.66) was obtained in the 60% ethanol extract. The G. lemaneiformis agar is composed of the biological precursor to agarobiose repeating units and agarobiose containing 6-0-methyl agarobiose and a small amount of 2-0-methyl-a-L-galactopyranose residues. Alkali treatment improved the chemical quality of the agar fractions, which was comparable with Japanese commercial agar and agarose.

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Seasonal Variations in Agar Yields and Quality from North Carolina Agarophytes

Cited by 37 publications

References 11 publications

Nitrogen assimilation following NH4+ pulses in the red alga Gracilariopsis lemaneiformis:effect on C metabolism

Nitrogen assimilation following NH4+ pulses in the red alga Gracilariopsis lemaneiformis:effect on C metabolism

Agar Analysis, nuclear genome quantification and characterization of four agarophytes (Gracilaria) from the Mexican Gulf Coast

Chemical composition of agars from a newly reported Japanese agarophyte, Gracilariopsis lemaneiformis

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