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.

Effects of kinetin and nitrogen on growth rates, pigment and protein contents in wild and phycoerythrin-deficient strains of Hypnea musciformis (Rhodophyta)

Hypnea musciformis (Wulfen in Jacqu.) J.V. Lamour. is the main source for carrageenan production in Brazil and strains with selected characteristics could improve the production of raw material. The effects of kinetin on growth rates, morphology, protein content, and concentrations of pigments (chlorophyll a, phycoerythrin, phycocyanin, and allophycocyanin) were assessed in the wild strain (brown phenotype) and in the phycoerythrin-deficient strain (green phenotype) of H. musciformis. Concentrations of kinetin ranging from 0 to 50 mu M were tested in ASP 12-NTA synthetic medium with 10 mu M nitrate (N-limited) and 100 mu M nitrate (N-saturated). In N-limited condition, kinetin stimulated growth rates of the phycoerythrin-deficient strain and formation of lateral branches in both colour strains. Kinetin stimulated protein biosynthesis in both strains. However, differences between both nitrogen conditions were significant only in the phycoerythrin-deficient strain. In the wild strain, effects of kinetin on concentrations of phycobiliproteins were not significant in both nitrogen conditions, except for chlorophyll content. However, the phycoerythrin-deficient strain showed an opposite response, and kinetin stimulated the phycobiliprotein biosynthesis, with the highest concentrations of phycoerythrin in N-saturated medium, while the highest concentrations of allophycocyanin and phycocyanin were observed in N-limited medium. These results indicate that the effects of kinetin on growth, morphology, protein and phycobiliprotein contents are influenced by nitrogen availability, and the main nitrogen storage pools in phycoerythrin-deficient strain of H. musciformis submitted to N-limited conditions were phycocyanin and allophycocianin, the biosynthesis of which was enhanced by kinetin.

Effects of Natural Radiation, Photosynthetically Active Radiation and Artificial Ultraviolet Radiation-B on the Chloroplast Organization and Metabolism of Porphyra acanthophora var. brasiliensis (Rhodophyta, Bangiales)

We undertook a study of Porphyra acanthophora var. brasiliensis to determine its responses under ambient conditions, photosynthetically active radiation (PAR), and PAR+UVBR (ultraviolet radiation-B) treatment, focusing on changes in ultrastructure, and cytochemistry. Accordingly, control ambient samples were collected in the field, and two different treatments were performed in the laboratory. Plants were exposed to PAR at 60 mu mol photons m(-2) s(-1) and PAR+UVBR at 0.35 W m(-2) for 3 h per day during 21 days of in vitro cultivation. Confocal laser scanning microscopy analysis of the vegetative cells showed single stellate chloroplast in ambient and PAR samples, but in PAR+UVBR-exposed plants, the chloroplast showed alterations in the number and form of arms. Under PAR+UVBR treatment, the thylakoids of the chloroplasts were disrupted, and an increase in the number of plastoglobuli was observed, in addition to mitochondria, which appeared with irregular, disrupted morphology compared to ambient and PAR samples. After UVBR exposure, the formation of carpospores was also observed. Plants under ambient conditions, as well as those treated with PAR and PAR+UVBR, all showed different concentrations of enzymatic response, including glutathione peroxidase and reductase activity. In summary, the present study demonstrates that P. acanthophora var. brasiliensis shows the activation of distinct mechanisms against natural radiation, PAR and PAR+UVBR.

Deleterious effect of TRIS buffer on growth rates and pigment content of Gracilaria birdiae Plastino & EC Oliveira (Gracilariales, Rhodophyta)

This work evaluated the effects of Tris (hydroxymethyl)-aminomethane (TRIS) buffer and its interaction with nutrient concentration on the development of Gracilaria birdie, a common species on the Brazilian coast that has been exploited for agar production. Responses to different conditions were assessed through growth rates and pigment content (chlorophyll a, phycoerythrin, phycocyanin and allophycocyanin). Provasoli`s nutrient solution with and without TRIS addition was tested at concentrations of 12.5, 25 and 50%. The pH was also monitored. G. birdiae grew better in the absence of TRIS and at low nutrient concentrations, 12.5 and 25% (growth rates of 10.8-11.3%.day(-1)). Higher contents of phycoerythrin and chlorophyll a were observed without TRIS at 12.5 and 25% (Phycoerythrin, 649.6-698.0 mu g g(-1) fresh biomass; Chlorophyll a, 156.0-168.6 mu g g(-1) fresh biomass). These findings highlight the deleterious effect of TRIS on growth and phycoerythrin and chlorophyll a content. They also demonstrate the importance of appropriate nutrient concentration for laboratory cultures, depending on the intrinsic characteristics of each species.

Color inheritance and pigment characterization of red (wild-type), greenish-brown, and green strains of Gracilaria birdiae (Gracilariales, Rhodophyta)

Species of Gracilaria are some of the most useful algae in the world for the production of agar. As a consequence of its economic importance, the genus has been the subject of many studies worldwide. Color variants of Gracilaria birdiae have been found in the natural population on the Brazilian coast, and they have also been isolated from plants cultivated in laboratory. These findings raised new questions regarding intraspecific variation and the prospects of cultivating such variants for their agar production. Therefore, this work aimed to determine the mode of color inheritance for two G. birdiae strains: a greenish-brown strain (gb) found in a natural population and a green strain (gr) which had arisen as a spontaneous mutation in a red plant cultured in the laboratory. The pigment contents of these strains, as well as the red wildtype (rd), were also characterized. Crosses between female and male plants of the same color (rd, gr, or gb) and between different colors were performed. Crosses between plants of the same color showed tetrasporophytic and gametophytic descendents of the parental color. Recessive nuclear inheritance was found in the greenish-brown strain, and cytoplasmic maternal inheritance was found in the green strain; both had lower phycoerythrin and higher concentrations of allophycocyanin and phycocyanin than the wild-type. Chlorophyll a contents were similar among all strains. Taken together, our results contribute to knowledge about the variability of this important red algae. In addition, since greenish-brown and green strains showed stability of color, both could be selected and tested in experimental sea cultivation to evaluate if mutants have advantageous performance when compared with red strain.

Toxic effects of dietary seaweeds Sargassum bovianum, Caulera faridii and Gracilaria corticata on blood parameters of albino rats

The present communication deals with the feeding trials of brown (Sargassum bovianum), green (Caulerpa faridii) and red (Gracilaria corticola) seaweeds in albino rats for a period of thirty days in order to investigate their digestibility and acceptability as supplementary food for animals. The parameters used were: changes in blood hemoglobin, ESR, MCHC, PCV and plasma vitamin levels. The result revealed that all the three species of seaweeds had acceptability up to 5% level, as no ill effect was noted during the experiment. But at 10% and 20% levels, marked changes were observed in blood parameters with diarrhea, vomiting and convulsions indicating possibilities of either tissue and muscular dystrophy, gastrointestinal tract necrosis or functional disorder of central nervous system. A heavy mortality was noted due to excessive water loss through diarrhea and vomiting. However, no mortality was observed after 22nd day at both 10% and 20% levels with subsided clinical signs. The results suggest that these three seaweed species could be used safely as a supplementary food, in native form, in animals at low concentrations.

The protein, peptide and free amino-acid contents of some species of Gracilaria from south-east coast of India

Four species of Gracilaria are investigated for their free amino-acid contents, as well as amino-acid constituents in the proteins and the peptides, using quantitative paper chromatographic technique. Amino-acid constituents of different species of Gracilaria differ only in amount, while free amino-acids and the amino-acids in the peptides vary both in quality and quantity. A number of amino-acids recorded as protein constituents have even escaped detection in the peptides, while in the free state they occur either in all the species or in some only except homocystine. Moreover, some amino-acids occur exclusively in the free state.

Small scale manufacture of crude agar from Gracilaria seaweeds

A simplified process was worked out to prepare crude agar from red seaweeds (Gracilaria sp.). The process required careful preliminary cleaning and bleaching (sun-drying) of the weed. The agar was extracted by boiling with water in a mixture (2%) strong enough to set as a jelly. Freezing the jelly over a 3—day period in an ice-making machine, adjusted to work slowly, separated out ice and agar. The blocks were thawed out and the agar dried in the sun. The efficiency of extraction was over 800/A.

Agar from Gracilaria lichenoides and Gracilaria confervoides from Ceylon

"Agar-agar" is a name derived from the jelly obtained from certain red algae in Malaya. In Sri Lanka agar is prepared from the red seaweeds Gracilaria confervoides and Gracilaria lichenoides. They are commonly known as Sri Lanka moss and the local names are "kandha parsi or sanchow parsi". The uses of agar are given together with details of the method of extraction of this substance from Gracilaria lichenoides and Gracilaria confervoides.

Cultivation of Gracilaria lichenoides in Puttalam Lagoon

A brief description is given of experimental rearing of the red alga G. lichenoides using a coir net frame method. Frames of 1x1 m were made and tied to bamboo poles which were planted in water; the frame was fixed at a level about 1 ft below the water level. 2 cm fragments were used as propagating material. Plants were found to grow more luxuriantly and were more greenish than using other methods, and in addition were free from extraneous matter such as sand. The regeneration time of the plant is low, and it reaches marketable size in 3-4 months.

Effects of solar UV radiation on diurnal photosynthetic performance and growth of Gracilaria lemaneiformis (Rhodophyta)

Previous studies on diurnal photosynthesis of macroalgal species have shown that at similar levels of photosynthetically active radiation (PAR, 400-700nm) the photosynthetic rate is lower in the afternoon than in the morning. However, the impacts of solar ultraviolet radiation (UVR, 280-400nm) have been little considered. We investigated the diurnal photosynthetic behaviour of the economically significant red alga Gracilaria lemaneiformis in the absence or presence of UV-A+B or UV-B with a flow-through system. While UV-A and UV-B, respectively, inhibited noontime Pmax by 22% and 14% on the sunny days, UV-A during sunrise (PAR below about 50Wm-2) increased the net photosynthesis by about 8% when compared with PAR alone. UV-A + PAR also resulted in higher apparent photosynthetic efficiency in the morning than in the afternoon period than PAR alone. Nevertheless, integrated daytime photosynthetic production under solar PAR alone was higher than with either PAR + UV-A+B or PAR + UV-A. Relative growth rate in the long term (9 days) matched the integrated photosynthetic production in that UV-A led to 9-15% and UV-B to 19-22% reduction, respectively. UV-absorbing compounds were found to be higher in the thalli exposed to PAR+UV-A+B than under PAR alone, reflecting a protective response to UVR.

Variations in morphology and PSII photosynthetic capabilities during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi) Papenfuss (Gracilariales, Rhodophyta)

Background: Red algae are primitive photosynthetic eukaryotes, whose spores are ideal subjects for studies of photosynthesis and development. Although the development of red alga spores has received considerable research attention, few studies have focused on the detailed morphological and photosynthetic changes that occur during the early development of tetraspores of Gracilaria vermiculophylla (Ohmi) Papenfuss (Gracilariales, Rhodophyta). Herein, we documented these changes in this species of red algae. Results: In the tetraspores, we observed two types of division, cruciate and zonate, and both could develop into multicellular bodies (disks). During the first 84 hours, tetraspores divided several times, but the diameter of the disks changed very little; thereafter, the diameter increased significantly. Scanning electron microscopy observations and analysis of histological sections revealed that the natural shape of the disk remains tapered over time, and the erect frond grows from the central protrusion of the disk. Cultivation of tissue from excised disks demonstrated that the central protrusion of the disk is essential for initiation of the erect frond. Photosynthetic (i.e., PSII) activities were measured using chlorophyll fluorescence analysis. The results indicated that freshly released tetraspores retained limited PSII photosynthetic capabilities; when the tetraspores attached to a substrate, those capabilities increased significantly. In the disk, the PSII activity of both marginal and central cells was similar, although some degree of morphological polarity was present; the PSII photosynthetic capabilities in young germling exhibited an apico-basal gradient. Conclusions: Attachment of tetraspores to a substrate significantly enhanced their PSII photosynthetic capabilities, and triggered further development. The central protrusion of the disk is the growth point, may have transfer of nutritive material with the marginal cells. Within the young germling, the hetero-distribution of PSII photosynthetic capabilities might be due to the differences in cell functions.

Transient expression of lacZ in particle bombarded Gracilaria changii (Gracilariales, Rhodophyta)

Using a Biolistic PDS 1000/He system, healthy thalli of Gracilaria changii were bombarded with gold particles coated with plasmid DNA containing the lacZ reporter gene. Transient expression of lacZ was observed in bombarded thalli under the rupture-disc pressures of 4482, 6206, 7584 and 8963 KPa, two days after bombardment. Although G. changii exhibits a slight blue background, positive expression and the background colour can be clearly differentiated. The results indicate that lacZ could be a useful reporter gene and that SV40 promoter could be an effective promoter for Gracilaria transformation.

Analysis of expressed sequence tags of a marine red alga, Gracilaria lemaneiformis

The expressed sequence tags (EST) has been proved to be a useful tool for discovering and identifying functional genes, especially in some species whose genetic information is unavailable. A total of 180 ESTs have been generated from a cDNA library of gametophytic Gracilaria lemaneiformis in this study. These clones are clustered into 151 groups, among which 8 groups are highly homologous to chloroplast genes and are abundant in the library. After searching for matches in the EST database of red alga, 22 groups are found to match with the registered ESTs of Rhadophyta and 6 with Gracilaria. Searching in the protein database reveal that 73 non-redundant clones have significant similarity to some known sequences, the majority of which are involved in photosynthesis, DNA transcription or translation, and 6, 4 and 3 clones are associated with growth or development, signal transduction and stress or defense response, respectively.