Chondracanthus Teedei Research Articles

Culture of Gracilaria gracilis and Chondracanthus teedei from Vegetative Fragments in the Field and Carpospores in Laboratory

Gracilarioids and Gigartinales are of great economic importance due to the phycocolloids they contain in their cell wall and are used in different industries worldwide. Field and laboratory cultures of two species of red seaweeds (Gracilaria gracilis and Chondracanthus teedei), confirmed after DNA analysis, were carried out to foster the increasing use of this species in Spain as a food source. Vegetative cultures carried out in an open-lock gate within a traditional salina in the ay of Cadiz (Southern Spain) rendered maximum growth rates in April (3.64% day−1) for G. gracilis and in November (4.68% day−1) for C. teedei, the latter showing significant differences between the months of the year. For laboratory cultures, samples of the two species used for sporulation were obtained from tidal creeks in several nearby locations of the Bay. In order to grow fertile carposporophytes from spores, Provasoli enriched seawater medium (ES medium), Miquel A + B and f/2 were used as culture medium at a temperature of 18 °C and irradiance of 30 µmol m−2 s−1 in 12:12 h photoperiod. Both species developed a basal disc after 12–15 days in ES medium and Miquel A + B, and new microscopic seedlings were observed at 20–25 days in ES medium. With f/2 medium, no growth was observed after sporulation. The life cycle of G. gracilis was completed in ES medium over a period of 11 months with a mean growth rate of 3.28% day−1. The present study is an important step towards the development of seaweed cultivation in the Bay of Cadiz, especially in integrated multi-trophic cultivation in salinas as part of the more sustainable use of the marine resources in coastal communities.

Potential Use of Carrageenans against the Limestone Proliferation of the Cyanobacterium Parakomarekiella sesnandensis

Stone biodeterioration by cyanobacteria is a common issue in the field of cultural heritage. As they are considered the first stone colonizers, the need to control their growth has increased. In this study, we evaluated the effectiveness of kappa/iota carrageenans from the red seaweed Chondracanthus teedei var. lusitanicus against the limestone proliferation of the cyanobacterium Parakomarekiella sesnandensis, under laboratory conditions. For this purpose, 200 μL of kappa/iota carrageenans (0.01 g mL−1) were applied into the surface of the limestone replicas prior to their inoculation with P. sesnandensis. Results were evaluated after 4 months of incubation through visual inspection, stereomicroscopy, scanning electron microscopy and colorimetric analyses. The gathered data demonstrated that these types of carrageenans have the potential to reduce the colonization of P. sesnandensis. With one sole application, the aesthetical alterations caused by the proliferation of P. sesnandensis were drastically reduced. This study highlights the need to explore marine-based products, particularly those derived from seaweeds with antimicrobial properties, as alternative methods for biocleaning cultural heritage assets.

Chondracanthus teedei var. lusitanicus: The Nutraceutical Potential of an Unexploited Marine Resource.

Presently, there is a high demand for nutritionally enhanced foods, so it is a current challenge to look at new raw food sources that can supplement beneficially the human diet. The nutritional profile and key secondary metabolites of red seaweeds (Rhodophyta) are gaining interest because of this challenge. In this context, the possible use of the red seaweed Chondracanthus teedei var. lusitanicus (Gigartinales) as a novel nutraceutical source was investigated. As a result, we highlight the high mineral content of this seaweed, representing 29.35 g 100 g−1 of its dry weight (DW). Despite the low levels of calcium and phosphorus (0.26 and 0.20 g 100 g−1 DW, respectively), this seaweed is an interesting source of nitrogen and potassium (2.13 and 2.29 g−1 DW, accordingly). Furthermore, the high content of carbohydrates (56.03 g 100 g−1 DW), which acts as dietary fibers, confers a low caloric content of this raw food source. Thus, this study demonstrates that C. teedei var. lusitanicus is in fact an unexploited potential resource with the capability to provide key minerals to the human diet with promising nutraceutical properties.

Seaweeds’ carbohydrate polymers as plant growth promoters

Currently, the high food demand led to a mass agriculture practices, whereas crop productivity is one of the major concerns for the producers. However, the intensification of the use of synthetic fertilizers has led to serious harmful impacts for human health and for the environment. The quest for novel and natural agricultural products is a current trend, hence seaweed polysaccharide bioactivity can contribute for this pursuit. The seaweed principal carbohydrates (agar, carrageenan and alginate) were extracted and chemically characterized from five red seaweeds, namely Gracilaria gracilis (Slender wart weed), Asparagospis armata (Harpoon weed), Calliblepharis jubata (False eyelash weed), Chondracanthus teedei var. lusitanicus and Grateloupia turuturu (Devil's tongue weed); and three brown seaweeds Colpomenia peregrina (Oyster thief), Sargassum muticum (Wireweed) and Undaria pinnatifida (Wakame). Afterwards, it was evaluated the impact of these sulphated polysaccharides on kale (Brassica oleracea) growth. Among the polymers tested, iota-carrageenan (from Calliblepharis jubata), kappa/ iota-carrageenan (from the female gametophyte of Chondracanthus teedei var. lusitanicus) and agar (from Gracilaria gracilis) showed a positive effect on kale growth. Through the quantification of polysaccharides and uronic acids, it appears that the polymer chemical structure is the decisive factor that affects the plant biostimulant activity.

Strain selection in Chondracanthus teedei (Gigartinaceae, Rhodophyta) using tetraspore and carpospore progeny: growth rates, tolerance to temperature and carrageenan yield

The feasibility of strain selection using tetraspore and carpospore progeny from wild fronds of Chondracanthus teedei to obtain strains with high growth rates, tolerance to temperature, and high yield of native carrageenan was investigated. A total of 34 strains were isolated, 14 from gametophytic progenitors and 20 from tetrasporophytic progenitors. The strains showed a heterogeneity of morphologies, colors, sizes, and growth. These differences were observed right from the early stages of development, resulting in individuals with more than one characteristic different from the others. Ninety days after selection, the strains differed in their growth rate, ranging from 0.57 to 5.13% day−1 in strains from gametophytic progenitors and 2.16 to 6.79% day−1 in strains from tetrasporophytic progenitors. When exposed to the temperature gradient, most strains (24 of 34) showed optimal growth rate values at the intermediate temperature used (25 °C) or without significant differences between 25 °C and one of the other temperatures used. However, four strains showed optimal growth rate values only at the extreme temperatures used and two gametophytic strains maintained their growth rate values without significant differences, irrespective of temperatures used, with a higher mean value for strain S27I (6.46 ± 0.07% day−1). The yields of carrageenan also varied among strains and temperatures with maximum value for strain S27I (74% DW for 15 °C and 25 °C; 73% DW for 30 °C). Thus, we believe that a combination of strains in different seasons could provide greater stability in biomass production and native carrageenan to, in turn, provide economically viable production.

Seaweeds as Valuable Sources of Essential Fatty Acids for Human Nutrition.

The overexploitation of terrestrial habitats, combined with the ever-growing demand for food, has led to the search for alternative food sources. The importance of seaweeds as food sources has been growing, and their potential as sources of fatty acids (FA) make seaweeds an interesting feedstock for the food and nutraceutical industries. The aim of this study is to assess the potential of five red seaweeds (Asparagospis armata, Calliblepharis jubata, Chondracanthus teedei var. lusitanicus, Gracilaria gracilis, and Grateloupia turuturu) and three brown seaweeds (Colpomenia peregrina, Sargassum muticum and Undaria pinnatifida), harvested in central Portugal, as effective sources of essential FA for food or as dietary supplements. FA were extracted from the biomass, transmethylated to methyl esters, and analyzed through gas chromatography-mass spectrometry. G. gracilis presented the highest content of saturated fatty acids (SFA) (41.49 mg·g−1), whereas C. jubata exhibited the highest content of highly unsaturated fatty acids (HUFA) (28.56 mg·g−1); the three G. turuturu life cycle stages presented prominent SFA and HUFA contents. Omega-6/omega-3 ratios were assessed and, in combination with PUFA+HUFA/SFA ratios, it is suggested that C. jubata and U. pinnatifida may be the algae with highest nutraceutical potential, promoting health benefits and contributing to a balanced dietary intake of fatty acids.

Determination of total iodine content in edible seaweeds: Application of inductively coupled plasma-atomic emission spectroscopy

Iodine is an essential element necessary for the synthesis of thyroid hormones, and its deficiency is a common problem worldwide. To avoid iodine insufficiency, the intake of this element must be properly evaluated concerning its adequate intake (AI), which is estimated at 90, 150, and 200 μg per day, for children, adults, and pregnant women, respectively. One of the most abundant resources available for iodine is the consumption of edible seaweeds. In this work, ten species of edible seaweeds: one green (Ulva rigida), five red (Chondracanthus teedei var. lusitanicus, Chondrus crispus, Gracilaria gracilis, Grateloupia turuturu, Osmundea pinnatifida), and four brown species (Bifurcaria bifurcata, Fucus vesiculosus, Saccorhiza polyschides, Undaria pinnatifida), collected from the near-pristine Portuguese seashore, were analyzed for iodine content. The iodine concentration was determined by optimized microwave-assisted extraction in aqua regia (AR), followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis. The method was validated by using the standard reference material (kelp) obtaining a maximum recovery of 100 ± 15%. The studied species contained a wide range of iodine concentrations, ranging from 33 ± 3 μg g−1 dry weight (dw) (U. rigida), up to 302 ± 26 μg g−1 dw (O. pinnatifida), 352 ± 21 μg g−1 dw (F. vesiculosus) and 391 ± 24 μg g−1 dw (B. bifurcata). The results show that the analyzed seaweeds can serve as a beneficial resource for iodine, however, their consumption must be balanced in a way that does not exceed the adequate estimated iodine intake for population groups.

A concise review of the red macroalgae Chondracanthus teedei (Mertens ex Roth) Kützing and Chondracanthus teedei var. lusitanicus (J.E. De Mesquita Rodrigues) Bárbara & Cremades

Chondracanthus teedei is a small red alga, whose fronds are cartilaginous membranous, dark crimson to red black, turning yellow-green due to decay. The main frond axes, due to their broad branches, reach 1 cm in the oldest portions in the case of the lusitanicus variety. Originally described in Portugal, C. teedei is found widespread in the Atlantic, Mediterranean, Black Sea and Indian Ocean. This cosmopolitan species is typical of lower intertidal and shallow subtidal habitats, of sciophilous habitats in semi-exposed or protected areas, and tolerates the presence of mud and sand. Its composition may vary according to the geographical location of origin, and the time of year when it is collected. It has relatively high levels of protein (14.66%), ash (28.68%), fibres (2.21%), lipids (1.82%) and moisture (86.73%), making this alga able to be considered for its implementation as food. In addition, C. teedei var. lusitanicus produces hybrid carrageenans belonging to the lambda family (xi-theta hybrid carrageenans), in the case of tetrasporophytes, and kappa-iota-mu-nu hybrid carrageenans, in the case of female gametophytes and non-fruited thalli. The carrageenans extracted from this species have antifungal and antiviral activities, and the dry ground biomass of C. teedei has potential to be used in cosmetic formulations.

Umami free amino acids in edible green, red, and brown seaweeds from the Portuguese seashore

The fifth basic taste—umami—is based on hydrophilic monosodium L-glutamate (L-Glu), and, to a smaller extent, on L-aspartate (L-Asp), which can be found in free form in seaweeds. The umami taste can be elicited by the synergistic effect of 5′-nucleotides, guanosine-5′-monophosphate (GMP), and inosine-5′-monophosphate (IMP). In this work, twelve edible seaweeds, two green (Codium tomentosum, Ulva rigida), six red (Chondracanthus teedei var. lusitanicus, Chondrus crispus, Gracilaria gracilis, Grateloupia turuturu, Nemalion helminthoides, Osmundea pinnatifida), and four brown (Bifurcaria bifurcata, Fucus vesiculosus, Saccorhiza polyschides, Undaria pinnatifida), from the Portuguese seashore, were selected for the analysis of umami amino acids and 5′-nucleotides. To determine the concentrations of umami free compounds, L-Glu, L-Asp, GMP, and IMP, the usual procedure for the preparation of seaweed’s broth was carried out, and the resulting extracts were analyzed by HPLC-DAD. The effect of the seaweed’s pretreatment, oven-dried and lyophilized, was also studied. Results showed that all seaweed species contained free amino acids in broad range, whereas umami 5′-nucleotides were not detected. The lyophilized C. crispus and G. gracilis contained the highest amounts of free L-Glu (627 ± 109 mg (100 g)−1 and 398 ± 67 mg (100 g)−1, respectively) and L-Asp (520 ± 102 mg (100 g)−1 and 270 ± 10 mg (100 g)−1, respectively). Two-factor PCA explained quantitatively (90%) the variance of seaweed species based on umami L-Glu content after different drying techniques applied. The results indicate that lyophilization constitutes a superior procedure for increasing the umami potential in most of the selected seaweeds.

Growth rates of Gracilariopsis longissima, Gracilaria bursa-pastoris and Chondracanthus teedei (Rhodophyta) cultured in ropes: implication for N biomitigation in Cadiz Bay (Southern Spain)

Cultures of three native macroalgal species (Gracilariopsis longissima, Gracilaria bursa-pastoris and Chondracanthus teedei) were developed in open coastal waters of a shallow, potentially eutrophic bay in Southern Spain. Experimental trials to assess the technical feasibility of seaweed cultivation and nitrogen biofiltration potential were conducted between October 2014 and December 2015. Seaweeds were cultivated using submersible rafts in five periods of 9 weeks to identify the most suitable seasons and culture duration (3, 6 or 9 weeks). Using generalized linear models (GLMs), the most relevant environmental factors controlling the growth of the three seaweeds were identified. Maximum net growth rates varied between 1.39% day−1 in C. teedei (winter, 6 weeks) and 4.71% day−1 in G. longissima (autumn, 3 weeks). Overall, the best period to cultivate seaweeds in Cadiz Bay was from mid-winter to early summer. No clear effects of duration of the culture were observed for C. teedei and G. bursa-pastoris. Short culture periods of 3 weeks were more suitable for G. longissima. Tissue N contents generally were lower than the critical quota, and GLMs suggested a critical role of N limiting seaweed growth in this bay. Dissolved inorganic nitrogen was biofiltered from winter to early summer and revealed G. bursa-pastoris as the main biomitigator of nitrogen (up to 80 mg N m−1 month−1 in spring). This species also showed positive growth rates virtually during the entire study period and was the most suitable species for cultivation in this area.

Concise review of genus Chondracanthus (Rhodophyta: Gigartinales)

Members of the genus Chondracanthus (Rhodophyta, Gigartinales) inhabit the shores of both hemispheres and have been used for decades in some countries as raw material for carrageenan extraction and in some cases destined for human consumption. This has created potential business opportunities, which has drawn the attention of scientists and producers and increased the number of scientific and applied research studies in the last few years. The broad morphological variation of Chondracanthus species makes necessary the use of molecular tools for species delimitation, which has led to the re-grouping and geographic re-distribution of some entities. The present study is a review of the available literature on members of the genus Chondracanthus, with the exception of Chondracanthus teedei, regarding their identity, distribution, ecology, life history, population structure, chemical traits, handling, and culture.

Are seaweeds the food of the future? Challenges for its conservation and introduction in the Portuguese diet

Introduction: Seaweeds are well known for their nutritional value [1]. The ALGA4FOOD project [https://alga4food.wixsite.com/pt-pt] [2] aims: i) researching new seaweed conservation processes (e.g. lyophilization, pascalization, MAP, etc.) which optimize functional and organoleptic characteristics; ii) develop strategies for its introduction in the Portuguese diet. Materials and methods 1 : Raw Materials: Seven seweed species (Ulva rigida, Codium tomentosum, Undaria pinnatifida, Saccorhiza polyschides, Gracilaria gracilis, Osmundea pinnatifida, Chondracanthus teedei var. Lusitanicus) were collected in north and central Portugal. Porphyra sp. and Ulva rigida for sensorial analysis were cultivated in an IMTA system. Instrumental Analysis: Each seaweed was frozen with liquid nitrogen and ground. Samples were maintained at −20 °C until microextraction by HS-SPME, using 30 g of fresh seaweed and 104 g of milli-Q water with 30% NaCl (PA). Ulva rigida was also dried and 6.75 g of the dried seaweed and 117 g of the saline solution were used. Compounds extracted were analyzed and identified by GC-MS. Product Development and Sensory Analysis: Dried pastas enriched with U. rigida and Porphyra sp. were developed and affective acceptance tests, using as control a 100% semolina (Triticum durum) pasta, were performed. The panel was composed by 60 untrained testers, and a structured hedonic scale of 1 to 9 points was used for the evaluation of appearance, color, aroma, texture, flavour, overall impression and food suitability. Data was submitted to analysis of variance (ANOVA), and Tukey’s multiple comparison tests. Results: Instrumental analysis: GC-MS identified 57 different organic compounds (167 in total): 28 aldehydes, 4 alcohols; 10 hydrocarbons; 3 ethers; 8 ketones; 4 other functional groups (1 containing sulphur, 2 iodine and 1 bromine). For U. rigida, results showed that the main compounds contributing for its fresh flavour profile (β-ionone and 2,4-decadienal) were different from those for the dried seaweed, meaning that fresh U. rigida has a higher aromatic richness than the dried one. Sensory analysis: The results showed no significant differences between the average values for texture, flavour, overall impression and food suitability. However, the appearance, colour and aroma attributes were significantly different particularly for the control and Porphyra sp. formulations [3]. Discussion and conclusions: The exploratory process showed that both instrumental and sensorial analysis, as well as the concepts underlying cooking creativity [3], are of great value for the development of new seaweed food products. GC-MS technique, together with sensory analysis, showed similarities between Undaria pinnatifida and collard greens (Brassica oleracea var. Acephala). Based on this, the seaweed was introduced in the traditional soup “caldoverde”, and preliminary tests showed good acceptance. Sensory analysis of pasta showed that green seaweed, due to their subtle maritime flavour, have a greater potential for cooking applications than the red seaweed [2,3].

Culture of Chondracanthus teedei and Gracilariopsis longissima in a traditional salina from southern Spain

The cultivation of two red macroalgal species, Chondracanthus teedei (Martens ex Roth) and Gracilariopsis longissima (S.G. Gmelin) Steentoft M, L.M. Irvine & W.F. Farnham, was assessed in a traditional salina, a system of earthen ponds used for marine salt extraction taking advantages of solar evaporation and tidal cycle. Vegetative thalli of both species were cultivated in rafts holding polypropylene ropes, from January to June 2015, when lock-gates were opened during the period of no salt production. The effects of three factors in the net growth rate were analysed: seedling density, water motion and seasonality. Water motion and seasonality showed a significant effect in the growth of both species. Seedling density only showed a significant effect in the growth of Gp. longissima, where the growth rates improved at high seedling densities. Values of tissue N were generally lower than critical quotas, suggesting that maximum growth was limited by the concentrations of dissolved nutrients. In addition, the high salinity and temperatures in late spring seemed to condition the values of net growth rate. The study suggested that macroalgal cultivation of these two valuable species could be a promising complementary activity in the integrated management of the salina during winter and early spring, when salinity is lower than 40 PSU, if nutrients in the water are increased with the semi-intensive fish cultivation and the hydrodynamic conditions along the rafts are enhanced.

Antifungal activity of carrageenan extracts from the red alga Chondracanthus teedei var. lusitanicus

Carrageenans extracted from Chondracanthus teedei var. lusitanicus were studied in order to determine their potential antifungal activity. FTIR-ATR and FT-Raman spectroscopic analysis confirmed the presence of a hybrid kappa/iota carrageenan belonging to the gametophyte phase and a hybrid xi/theta carrageenan in the tetrasporophyte phase. Kappa/iota and xi/theta carrageenan induced the formation of swollen hyphal segments in Alternaria infectoria, upon exposure to 125 and 60 μg mL−1, respectively. The observed phenotype was similar to those induced by antifungals targeting the fungal cell wall. When exposed to 87.5 μg mL−1 of kappa/iota carrageenan, Aspergillus fumigatus hyphae became shortened and highly branched, a phenotype commonly observed in response to antifungals. These morphological alterations were associated with a decrease of the β-glucan content in A. infectoria after exposure to 150 μg mL−1 of kappa/iota and to 100 μg mL−1 of xi/theta carrageenan. On the other hand, the chitin cell wall content of A. fumigatus decreased significantly upon exposure to 150 μg mL−1 of both extracts, which triggered an increase in the content of β-glucan. Overall, the present work shows that carrageenans extracted from C. teedei var. lusitanicus cause alterations on the A. fumigatus and A. infectoria cell walls, indicating a marked antifungal activity.

Alterations in architecture and metabolism induced by ultraviolet radiation-B in the carragenophyte Chondracanthus teedei (Rhodophyta, Gigartinales)

The in vivo effect of ultraviolet radiation-B (UVBR) in apical segments of Chondracanthus teedei was examined. Over a period of 7days, the segments were cultivated and exposed to photosynthetically active radiation (PAR) at 80μmolphotonsm(-2)s(-1) and PAR + UVBR at 1.6W m(-2) for 3h per day. The samples were processed for electron microscopy and histochemistry; also was analyzed growth rates, mitochondrial activity, protein levels, content of photosynthetic pigments and photosynthetic performance. UVBR elicited increased cell wall thickness and accumulation of plastoglobuli, changes in mitochondrial organization and destruction of chloroplast internal organization. Compared to controls, algae exposed to PAR + UVBR showed a growth rate reduction of 55%. The content of photosynthetic pigments, including chlorophyll a and phycobiliproteins, decreased after exposure to PAR + UVBR. This result agrees with the decreased photosynthetic performance observed after exposing algae to PAR + UVBR. Irradiation also elicited increased activity of the antioxidant enzyme glutathione peroxidase and decreased mitochondrial NADH dehydrogenase activity, which correlated with the decreased protein content in plants exposed to PAR + UVBR. Taken together, these findings strongly indicate that UVBR negatively affects the architecture and metabolism of the carragenophyte C. teedei.

Portuguese carrageenophytes: Carrageenan composition and geographic distribution of eight species (Gigartinales, Rhodophyta)

Eight carrageenophytes from the Centre and North coast of Portugal, representing seven genera and three families of Gigartinales, were studied in 15 different coastal stations in a geographic study, from Baleal (Peniche), in the central zone, to Moledo, in the northern zone.In order to characterize the different carrageenan types, 1H NMR spectroscopy was used to identify and quantify the different carrageenan fractions in the extracted phycocolloids (both water and alkali extractions). Thereby, detailed information concerning the properties and structure of these polysaccharides at molecular level was revealed.Based on the results of the analysis of the carrageenan types, the following conclusions were made: female gametophytes and non-fertile thalli of Chondrus crispus, Mastocarpus stellatus, Chondracanthus teedei var. lusitanicus, Gigartina pistillata, Chondracanthus acicularis and Gymnogongrus crenulatus, presented a varying degrees of kappa–iota hybrid carrageenan (co-polymers of kappa–iota carrageenan). The kappa/iota ratio ranged from 0 to 2.2. The carrageenans extracted from Ahnfeltiopsis devoniensis were mainly iota-carrageenan, but some geographic variations in the composition of carrageenans were found. Calliblepharis jubata contained carrageenans of iota-type in all reproductive stages. Lambda-family carrageenans were found in tetrasporophytes of C. cripus (lambda), M. stellatus (lambda), C. teedei var. lusitanicus (hybrid xi–theta), C. acicularis (hybrid xi–theta) and G. pistillata (hybrid xi–lambda).

ENDOGENOUS CYTOKININS, AUXINS, AND ABSCISIC ACID IN RED ALGAE FROM BRAZIL1

Endogenous cytokinins, auxins, and abscisic acid (ABA) were identified and quantified in 11 red algae collected from the Brazilian coast. Field materials and two isolates cultured in the laboratory were extracted with various solvents and buffers containing a mixture of appropriate internal standards, purified by solid‐phase extraction followed by immunoaffinity chromatography, and analyzed by liquid chromatography–tandem mass spectrometry. Isoprenoid cytokinins (free and conjugated forms of isopentenyladenine [iP], cis‐zeatin [cZ], and trans‐zeatin [tZ]) were detected in all species with concentrations of cZ and iP forms being higher than tZ forms. Dihydrozeatin (DHZ) and its metabolites were only detected at very low levels in nine of the studied species. Aromatic cytokinins (6‐benzylaminopurine [BA], ortho‐ and meta‐topolin [oT and mT]) were not detected in any of the samples. The cytokinin profile of Chondracanthus teedei (Mert. ex Roth) Kütz. was distinct in comparison to other species with para‐topolin (pT) derivatives detected in low concentrations. The main auxins present in all species were free indole‐3‐acetic acid (IAA) and indole‐3‐acetamide (IAM). Indole‐3‐ethanol (IEt), indole‐3‐acetyl glutamic acid (IAGlu), and indole‐3‐acetyl leucine (IALeu) were detected in a few species at low concentrations. ABA was present in all species analyzed except for Hypnea nigrescens Grev. ex J. Agardh. No ABA conjugates were detected in any species. These results confirm that cytokinins, auxins, and ABA were common constituents in red seaweeds, with this being the first report of the occurrence of ABA in Rhodophyta. The complexity of the hormone profiles suggests that plant hormones play a role in regulating physiological processes in Rhodophyta.

A comparative analysis of phycocolloids produced by underutilized versus industrially utilized carrageenophytes (Gigartinales, Rhodophyta)

Carrageenan (E-407) and semi-refined carrageenan (E-407a) are some of the main additives used by the food industry for their gelling, emulsifying, thickening, and stabilizing properties. These are natural ingredients, which have been used for decades in food applications and are generally regarded as safe. Internationally, sub-tropical carrageenophytes (e.g., Kappaphycus alvarezii) are cultivated extensively as a source of raw materials for industrial extraction, and their use as potential candidates in integrated multitrophic aquaculture is tentative. We analyzed carrageenan yield (as a percentage of dry weight) and chemical composition (by Fourier transform infrared attenuated total reflection and Fourier transform-Raman) of extracts produced by several carrageenophytes (Gigartinales, Rhodophyta), from different origins, e.g., K. alvarezii (Tanzania, Indonesia, the Philippines, Panama, and Mexico), Kappaphycus striatum (Madagascar), Eucheuma denticulatum (Tanzania, the Philippines, and Madagascar), Betaphycus gelatinum (the Philippines), Chondracanthus chamissoi, and Sarcothalia crispata (Chile). For comparison, some underutilized carrageenophytes were also analyzed, e.g., Chondrus crispus, Mastocarpus stellatus, Gigartina pistillata, Chondracanthus teedei var. lusitanicus, Chondracanthus acicularis, Calliblepharis jubata, Gymnogongrus crenulatus, and Ahnfeltiopsis devoniensis (Portuguese carrageenophytes). The main findings were that the highest carrageenan yield was obtained from K. striatum (Madagascar) with 75.6 (percent dry weight (% DW)); B. gelatinum and K. alvarezii (both from the Philippines) had yields of 71.0% and 68.0% (% DW), respectively; and G. pistillata (Portugal) 65.4% (% DW). Spectroscopic analysis of the phycocolloids allowed determination of a wide range of carrageenan types, e.g., pure iota carrageenan, several kappa–iota hybrid carrageenans with different iota/kappa ratios, and kappa–beta, xi–theta, and xi–lambda hybrid carrageenans.

Use of FTIR, FT-Raman and 13C-NMR spectroscopy for identification of some seaweed phycocolloids

Many seaweeds produce phycocolloids, stored in the cell wall. Members of the Rhodophyceae produce polysaccharides the main components of which are galactose (galactans)—agar and carrageenan. In addition, alginic acid is extracted from members of the Phaeophyceae. This is a binary polyuronide made up of mannuronic acid and guluronic acid. The wide uses of these phycocolloids are based on their gelling, viscosifying and emulsifying properties, which generate an increasing commercial and scientific interest. In this work, the FTIR and FT-RAMAN spectra of carrageenan and agar, obtained by alkaline extraction from different seaweeds (e.g. Mastocarpus stellatus, Chondrus crispus, Calliblepharis jubata, Chondracanthus acicularis, Chondracanthus teedei and Gracilaria gracilis), were recorded in order to identify the type of phycocolloid produced. The spectra of commercial carrageenan, alginic acid and agar samples (SIGMA and TAAB laboratories) were used as references. Special emphasis was given to the 500–1500 cm −1 region, which presents several vibrational modes, sensitive to the type of polysaccharide and to the type of glycosidic linkage. The FT-Raman spectra present a higher resolution than FTIR spectra, this allowing the identification of a larger number of characteristic bands. In some cases, phycocolloids can be identified by FT-Raman spectroscopy alone.

Carrageenophytes of occidental Portuguese coast: 1-spectroscopic analysis in eight carrageenophytes from Buarcos bay

Infrared and Raman spectroscopic analysis of the carrageenan (alkaline extraction) in eight species (representing seven genera and four families) of Gigartinales, in different reproductive phases from Buarcos bay (Figueira da Foz, Portugal), were studied. Female gametophytes and non-fertile thalli samples of Chondrus crispus, Mastocarpus stellatus, Chondracanthus teedei var. lusitanicus, Gigartina pistillata and Chondracanthus acicularis present a κ-carrageenan profile or varying degrees of a κ–ι hybrid. The presence of κ–ι hybrid carrageenan in C. teedei var. lusitanicus was confirmed by 13C NMR . The carrageenans extracted from Gymnogongrus crenulatus and Ahnfeltiopsis devoniensis are constituted mainly by ι-carrageenan but seasonal variations in the nature of carrageenans are present. λ-Family carrageenans were found in tetrasporophytes of C. crispus, M. stellatus, C. teedei var. lusitanicus, C. acicularis and G. pistillata. Calliblepharis jubata presents carrageenans of ι-type in all reproductive stages.