Porphyra Sp Research Articles

Proximate Composition, Physicochemical and Microbiological Characterization of Edible Seaweeds Available in the Portuguese Market.

The aim of this work was the study of the proximate composition and profile of fatty acids, minerals, and some microbiological aspects of four edible seaweed species (Chondrus crispus, Palmaria palmata, Porphyra sp., and Ulva sp.) available in the Portuguese market for food consumption, and produced in a national Integrated Multi-Trophic System (IMTA). Moisture, ash, and total lipids were determined gravimetrically. Crude protein was analysed by Duma's combustion procedures. The total carbohydrate content was assayed by the phenol/sulphuric acid method. The assessment of the fatty acids methyl esters (FAMEs) was determined through GC-MS. Characterization of elemental analysis was performed by ICP-AES. Different standard microbiological methods were applied for microorganisms. Statistics were performed using the non-parametric Mann-Whitney U test to assess significant differences between samples. Lipid contents (n = 3) were very low (1.6-2.3%), particularly in Palmaria palmata, and Chondrus crispus (1.6-1.7%). The protein content (n = 4) varied from 14.4% in P. palmata to 23.7% in Porphyra sp. Carbohydrates (n = 3) were the major constituent of most seaweeds (31-34%), except in Porphyra sp., with higher content in proteins than carbohydrates. Regarding the fatty acid content (n = 4), in general, saturated fatty acids (SFAs) were the most abundant followed by polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs). Among macro and trace elements (n = 3), Chondrus crispus shows the highest average content in Zn (71.1 mg ⋅ kg - 1 D.W.), Palmaria palmata the highest average content in K (124.8 g ⋅ kg - 1 D.W.), Porphyra sp. the highest average content in P (2.1 g ⋅ kg - 1 D.W.), and Ulva sp. the highest average content of Ca (5.5 g ⋅ kg - 1 D.W.), Mg (55.8 g ⋅ kg - 1 D.W.), and Fe (336.3 mg ⋅ kg - 1 D.W.). In general, Na and K were the most abundant elements among analysed seaweed. Additionally, the microbiological results (n = 4) comply with the Portuguese guidelines (subgroup 2D) on the application of general principles of food hygiene in ready-to-eat foods. Overall, the results highlight the potential of using these seaweeds as an alternative and sustainable source of elements and bioactive compounds to produce enriched food products with a beneficial potential for human nutrition.

JARING SEBAGAI SUBSTRAT BUATAN PENEMPELAN SPORA Porphyra sp DI PERAIRAN NEGERI HUKURILA

Hukurila waters have the potential to develop a macro type of algae Porphyra sp. The technique of casting a net that is used as an artificial substrate as a place for sticking spores is interesting to experiment with, which has always only utilized this Porphyra from nature during the eastern season. This activity aims to apply the technique of making artificial subsrats using nets in increasing Porphyra yields. The activity began with the planting of pieces of wood as long poles to tie the net. After the piles have been well embedded then, the net is then opened and tied at every angle from the net to the wooden pole using nylon rope. At the end of this activity, it was seen that there was an understanding of the use of nets as an artificial substrate for pasting Porphyra spores. This activity is very beneficial for the community in increasing the number of crops through the technique of making artificial substrates as a medium for sticking spores during the eastern season

Study of the use of Gracilaria sp from the Karawang Area and Ulva lactuca as raw material making of Nori

Nori is processed seaweed in the form of dried sheets, generally consumed by Japanese and Korean people. The seaweed used as raw material is Porphyra sp which generally grows in Japan and Korea, so Indonesia has to import more and more nori. Porphyra seaweed is the raw material for making imported nori. Porphyra is not found in Indonesia because the seaweed lives in a subtropical climate. Therefore, it is necessary to look for alternative raw materials besides Porphyra. Indonesian waters have various types of seaweed, one of which is Ulva lactuca seaweed. Ulva Lactuca is one of the red algae plants and belongs to the class Chlorophyceae, shaped like sheet talus like lettuce. Ulva Lactuca has similar characteristics to Porphyra seaweed in terms of texture and color besides that Ulva Lactuca is rich in acrylic acid which functions as an antibiotic, is a source of protein, folic acid, and several types of minerals such as: Ca, K, Mg, Na, Cu, Fe, Zn. Apart from the type of Ulva Lactuca, there are also types of Gracilaria verrucosa often found in Karawang waters. Gracilaria produced in these waters has quite high gel strength and viscosity. The advantages of these properties are expected to improve the quality of the nori products produced. For this reason, in this applied research a study was conducted to make nori with a combination of Gracilaria sp and Ulva sp. Ulva sp (sea lettuce) used is Ulva Lactuca in Pangandaran waters. The manufacturing process begins with washing the seaweed and soaking the seaweed for 6 hours. Ulva Lactuca soaked in NaCl solution with a weight ratio of seaweed: water: salt = 2: 60: 5, soaking seaweed Gracilaria sp. in a solution of rice vinegar with a weight ratio of seaweed: water: rice vinegar = 2: 60: 1. Experiments were carried out in 4 weight ratios of Gracilaria sp. that is different, namely: sample 1 = 100% Ulva lactuca, sample 2 = 97.15% Ulva lactuca: 2.85% Gracilaria sp., Sample 3 = 98% Ulva lactuca: 2% Gracilaria sp., and sample 4 = 99% Ulva lactuca: 1% Gracilaria sp.

Selective incorporation of rare earth elements by seaweeds from Cape Mondego, western Portuguese coast

This study examined the mechanism of incorporation of the rare earth elements (REEs), La, Ce, Nd, Eu, Gd, Tb, Yb, into green (Codium tomentosum, Ulva rigida), red (Gracilaria gracilis, Osmundea pinnatifida, Porphyra sp), and brown seaweeds (Saccorhiza polyschides, Undaria pinnatifida) collected from a single site near the coastline of the Cape Mondego, western Portugal. The concentrations of REEs, Mg, Ca, Al, Fe, Zn, and Cu in the biomasses were determined by inductively-coupled plasma mass spectrometry (ICP-MS). The species showed differences in their incorporation and fractionation of REEs from the same environment: the sum of REEs was higher in U. rigida, C. tomentosum, G. gracilis, and O. pinnatifida (0.7–1.7 μg g−1) than in Porphyra sp., S. polyschides, and U. pinnatifida (0.1–0.2 μg g−1). Ratios of Ce/Yb ranged from 13 (in S. polyschides) to 103 (in U. rigida), indicating different proportions of light and heavy REEs among species. Good correlations were found between Al and Fe (R2 = 0.98), and between these elements and La, Ce, Nd, Gd (R2 = 0.88–0.97) and Yb (R2 = 0.66–0.71) for all species except C. tomentosum and G. gracilis. Profiles of REE values normalised to average upper-continental crust composition indicated positive anomalies of Eu and Tb that reinforced the singularity of these elements in the REE group. Correlations between the REEs and Al or Fe suggest that detrital terrigenous particles, adhered to seaweed walls, may be an important mechanism for the incorporation of REEs by seaweeds. Different patterns for C. tomentosum and G. gracilis may also be indicative of the higher influence of cell wall composition on REE incorporation.

Determinación de la actividad tóxica de extractos optimizados de Palmaria y Porphyra para el tratamiento de la lesión por isquemia/reperfusión


 La lesión por isquemia-reperfusión (I/R) puede provocar rechazos en los trasplantes de órganos debido al daño a nivel celular que producen los Radicales Libres de Oxígeno (ROS). Se ha comprobado que los antioxidantes naturales pueden reducir este daño. Los extractos de muchas algas poseen una actividad antioxidante notable, pero se necesita comprobar la toxicidad de estos antes de proponerlos como fármacos. En este estudio, se realizaron dos ensayos toxicológicos con queratinocitos humanos inmortalizados (HaCaT) y nauplios de Artemia salina para valorar la toxicidad de dos extractos con actividad antioxidante de Palmaria palmata y Porphyra sp. Se obtuvieron LC50 de 7,843% (v/v) de concentración de extracto en P. palmata en el ensayo con HaCaT y 3,2583% (v/v) en el ensayo con A. salina, mientras que con Porphyra sp. se obtuvo 10,7463% (v/v) en el ensayo con HaCaT y 6,5688% (v/v) en el ensayo con A. salina. Los Niveles Sin Efecto Adverso Observable (NOAEL) obtenidos para cada alga en cada ensayo mostraron significativamente una mayor toxicidad del extracto de P. palmata que del de Porphyra sp. (p < 0,05). Finalmente, se propuso un índice que tiene en cuenta la actividad antioxidante y la toxicidad de cada extracto para predecir su eficiencia in vivo, confirmando los resultados anteriores, y por ello se escogió el extracto de Porphyra sp. como el más idóneo para continuar con los ensayos preclínicos en el desarrollo de un fármaco para el tratamiento de la lesión por I/R.

Ruminal Fermentation, Growth Rate and Methane Production in Sheep Fed Diets Including White Clover, Soybean Meal or Porphyra sp.

Simple SummaryIn ruminant feeding, the use of diets containing seaweeds could be a valuable alternative to conventional diets. The objective of this work was to investigate the ruminal fermentation, growth rate and methane production in sheep fed a diet including Porphyra sp. compared with diets including clover silage or soybean meal. Including Porphyra sp. had little impact on ruminal fermentation and methane production both in vitro and in vivo. Lambs fed Porphyra sp. had a similar growth rate to those fed a diet including soybean meal, confirming previous in vitro and in situ observations on the high-quality protein of Porphyra sp. in ruminant feed.The aim of the present work was to investigate the potential of Porphyra sp. as an alternative source of protein to soybean meal in diets for sheep. Our experimental treatments included a control diet (CON) based on grass silage and crushed oats and three diets containing protein supplements, clover silage (CLO), soybean meal (SOY) or Porphyra sp. (POR) to increase dietary crude protein concentrations. We studied its effects on rumen fermentation, growth rate and methane emissions. Ruminal fermentation characteristics, kinetics of gas production and methane production were studied in vitro by using batch cultures inoculated with rumen inoculum from sheep. There were no differences among diets in total volatile fatty acids (VFA) production or in the VFA profile in vitro. Across treatments, we measured no differences in methane production either in vitro or in vivo, and we saw no noticeable antimethanogenic effect of Porphyra sp. The present in vivo trial with lambs showed no differences in average daily weight gain when fed diets including Porphyra sp. or soybean meal diets (250 and 254 g/d, respectively). We conclude that Porphyra sp. has a protein value similar to high-quality protein sources like soybean meal.

Composition analysis of selected Sri Lankan seaweeds

Seaweeds are a rich source of health beneficial bioactive nutraceuticals and currently they are under-utilized in Sri Lanka. In the present study, proximate analysis of seaweed varieties Chnoospora minima and Porphyra sp. obtained from Mirissa, Matara, Sri Lanka and Ulva fasciata was taken from Point Dondra Matara, Sri Lanka on June, 2018 were investigated. The moisture content, total fat content, protein content and ash content were determined according to the Official methods of Analysis by Association of Official Analytical Chemists after drying for 8h at 600 C. The results revealed that the moisture contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 13.24 ± 0.20, 14.30 ± 0.14 and 18.11 ± 0.01 respectively. Total fat contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 0.21 ± 0.11, 0.19 ± 0.03 and 0.28 ± 0.05 respectively. Protein contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 13.70 ± 0.2, 21.14 ± 0.04 and 11.84 ± 0.1. Total ash contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 17.20 ± 0.24, 5.40 ± 0.7 and 18.05 ± 0.21 respectively. Total carbohydrate content (%) was analyzed according to the Dubois method. Chnoospora minima, Porphyra sp. and Ulva fasciata showed total carbohydrate content (%) as 3.87 + 0.66, 20.59 ± 0.24 and 7.68 ± 1.16 respectively. Moreover, the sulphate content was analyzed according to the precipitate method. Chnoospora minima, Porphyra sp. and Ulva fasciata showed 1.45 ± 0.35, 2.75 ± 0.07 and 4.54 ± 0.06, sulfate contents (%) respectively. In conclusion, highest ash content which indicates a good mineral content was observed in Ulva fasciata and Chnoospora minima. Fibre, protein and carbohydrate contents are significantly different among the 3 samples. Highest fibre content was observed in Chnoospora minima. Highest protein and carbohydrate contents were observed in Porphyra sp. But there is no significant difference in fat contents among the three samples.

In vitro ruminal fermentation and methane production of different seaweed species

Seaweeds have potentials as alternative feed for ruminants, but there is a limited knowledge on their nutritive value. Seven seaweed species collected along the coast above the Arctic circle of Norway, both in spring and autumn, were assessed for nutrients and total polyphenols (TEP) content, gas production kinetics and in vitro rumen fermentation in batch cultures of ruminal microorganisms. The seaweeds were three red species (Mastocarpus stellatus, Palmaria palmata and Porphyra sp.), three brown species (Alaria esculenta, Laminaria digitata and Pelvetia canaliculata) and one green species (Acrosiphonia sp.). Additionally, the abundance and diversity of total bacteria, protozoa and archaea in the cultures with the three red seaweeds collected in spring were analyzed by quantitative PCR and PCR-DGGE, respectively. The crude protein (CP) content varied widely. Pelvetia had the greatest (P<0.001) ether extract (EE) content. Non-structural carbohydrates (NSC) content varied from 135 to 541g/kg DM with brown seaweeds having the greatest values. Ash and CP contents were higher in spring than in autumn (P=0.020 and 0.003, respectively), whereas concentrations of EE and NSC were not affected by collecting season (P=0.208–0.341). The TEP values ranged from 1.46 to 50.3mg/g dry matter (DM), and differed (P<0.001) among seaweed species and collecting season, being greater in autumn than in spring. The DM effective degradability (DMED), estimated from gas production parameters for a rumen passage rate of 3.0% per h, ranged from 424 to 652g/kg, the highest values were recorded for Mastocarpus stellatus and Porphyra sp. The lowest DMED values were registered for Pelvetia canaliculata and Acrosiphonia sp. In 24-h incubations (500mg DM), Palmaria palmata had the highest (P<0.05) volatile fatty acids (VFA) and methane production (4.34 and 0.761mmol, respectively) and the lowest (P<0.05) final pH values and acetate to propionate ratios (6.57 and 2.34, respectively). There were no differences (P>0.05) among the other seaweeds in VFA production, but Porphyra sp. had the second highest methane production (P<0.05; 0.491mmol) compared with the other seaweeds (0.361mmol; averaged value). The methane/total VFA ratio was not affected (P>0.05) by either seaweed species or the collection season. Higher final pH (P<0.05) and lower (P<0.05) methane and VFA production, ammonia-N concentrations and DMED values were promoted by the fermentation of seaweed collected in autumn compared with those from spring. Among the red seaweeds, there were no species-specific differences (P>0.05) in the abundance or the diversity of total bacteria, protozoa and archaea. In the PCR-DGGE analysis, samples were separated by the incubation run for all microbial populations analyzed, but not by seaweed species. The results indicate that seaweed species differ markedly in their in vitro rumen degradation, and that samples collected in autumn had lower rumen degradability than those collected in spring.

New insights into the biodiversity and generic relationships of foliose Bangiales (Rhodophyta) in Iceland and the Faroe Islands

Foliose species of the Bangiales (Porphyra sensu lato) have a long history of study in the N Atlantic, but there are still regions, especially in the northern parts of the N Atlantic that need more attention. A molecular study using rbcL and cox1 sequences was undertaken to assess the diversity of foliose Bangiales species in Iceland and the Faroe Islands. Herbarium collections from the intertidal and subtidal of Iceland (summer and winter) and the Faroe Islands (all seasons) revealed a total of 13 species (11 common to both areas), which were referred to four of the genera recognized in a recent two-gene global phylogeny. Boreophyllum birdiae, Porphyra dioica, P. linearis, P. purpurea, P. umbilicalis, Pyropia ‘leucosticta’ A, Pyropia njordii Mols-Mortensen, J. Brodie & Neefus, sp. nov., Wildemania amplissima and W. miniata were common to both areas, while Pyropia thulaea and Wildemania abyssicola (Kjellman) A. Mols-Mortensen & J. Brodie, comb. nov. (=Porphyra abyssicola Kjellman) were reported from Iceland but not from the Faroe Islands; Porphyra sp. FO and Pyropia elongata were reported from the Faroe Islands but not from Iceland. Boreophyllum birdiae is reported for the first time for Iceland and Porphyra sp. FO is reported for the first time for the Faroe Islands. Pyropia njordii is described from the Faroe Islands and is also recorded for Iceland, Greenland, New England, USA and Nova Scotia, Canada. A total of 25 foliose Bangiales species are now reported from the N Atlantic and these results demonstrate the importance of investigating as many areas as possible to reach a more complete understanding of species diversity and distribution.

High Iron Content and Bioavailability in Humans from Four Species of Marine Algae ,

Searching for economical, nonconventional sources of iron is important in underdeveloped countries to combat iron deficiency and anemia. Our objective was to study iron, vitamin C, and phytic acid composition and also iron bioavailability from 4 species of marine algae included in a rice-based meal. Marine algae (Ulva sp, Sargassum sp, Porphyra sp, and Gracilariopsis sp) were analyzed for monthly variations in iron and for ascorbic acid and phytic acid concentrations. A total of 96 subjects received rice-based meals containing the 4 species of marine algae in different proportions, raw or cooked. All meals contained radioactive iron. Absorption was evaluated by calculating the radioactive iron incorporation in subjects’ blood. Iron concentrations in algae were high and varied widely, depending on the species and time of year. The highest iron concentrations were found in Sargassum (157 mg/100 g) and Gracilariopsis (196 mg/100 g). Phytates were not detected in the algae and ascorbic acid concentration fluctuated between 38 μg/g dry weight (Ulva) and 362 μg/g dry weight (Sargassum). Algae significantly increased iron absorption in rice-based meals. Cooking did not affect iron absorption compared with raw algae. Results indicate that Ulva sp, Sargassum sp, Porphyra sp, and Gracilariopsis sp are good sources of ascorbic acid and bioavailable iron. The percentage of iron absorption was similar among all algae tested, although Sargassum sp resulted in the highest iron intake. Based on these results, and on the high reproduction rates of algae during certain seasons, promoting algae consumption in some countries could help to improve iron nutrition.

Identification of north-western Atlantic Porphyra (Bangiaceae, Bangiales) based on sequence variation in nuclear SSU and plastid rbcL genes

Six species of Porphyra have commonly been recognized in the north-western Atlantic from Long Island Sound to the Canadian Maritimes: P. amplissima, P. leucosticra, P. linearis, P. miniata, P. purpurea, and P. umbilicalis. Distinguishing them with certainty has been problematic. A DNA-based system of molecular identification was developed using partial sequences of the nuclear small subunit ribosomal RNA gene (SSU) or the plastid ribulose-1,5-bisphosphate carboxylase–oxygenase large subunit gene (rbcL). Multiple samples of each taxon were surveyed for intraspecific variation. Intraspecific SSU divergences for Porphyra ‘leucosticta’, P. ‘miniata’, P. ‘umbilicalis’, and P. ‘purpurea’ ranged from 0% to 1%. There was more variation for P. ‘amplissima’ (0–2.1%) and P. ‘linearis’ (0–3.5%); however, each taxon was monophyletic. No intraspecific differences were observed for these taxa in rbcL (one to eight samples per taxon). These sequences were compared with P. yezoensis U51, introduced to Maine, and with P. ‘dioica’, a north-east Atlantic Porphyra easily confused with P. ‘purpurea’. To discriminate between P. ‘purpurea’, P. ‘umbilicalis’, and P. ‘leucosticta’, SSU variation was used to design primers for the Allele-Specific Polymerase Chain Reaction™. With molecular tools, we could classify over 80% of the monostromatic specimens surveyed, but the residue of unidentifiable specimens may indicate the existence of further monostromatic species in the north-west Atlantic. Porphyra ‘purpurea’ was found to occur further south than previously recorded. A morphologically cryptic Porphyra was discovered at Herring Cove, Nova Scotia, Canada.† Phylogenetic analyses using SSU or rbcL sequences showed ‘soft incongruence’ between gene trees, i.e. the topologies of the phylograms were similar but not identical, with only weak to moderate bootstrap support for the nodes that differed. Both trees strongly supported a clade including P. ‘purpurea’, P. ‘umbilicalis’, P. ‘linearis’, and P. ‘dioica’. Porphyra sp. Herring Cove was allied with the remaining Porphyra taxa in the SSU tree. The rbcL phylogeny was less well resolved, consisting of a polytomy of a P. ‘purpurea’–P. ‘umbilicalis’–P. ‘linearis’–P. ‘dioica’ clade, Porphyra sp. Herring Cove, a clade comprising P. ‘amplissima’ and P. ‘miniata’, and a P. ‘suborbiculata’–P. ‘leucosticta’–P. yezoensis clade.

GROWTH OF CULTURED ABALONE, HALIOTIS FULGENS, USING NATURAL ALGAL DIETS

Pérez‐Estrada, C. J.1,2, Serviere‐Zaragoza, E.1, Mazariegos‐Villareal, A.1, Reynoso‐Granados, T.1 &amp; Monsalvo‐Spencer, P.1 1Centro de Investigaciones Biológicas del Noroeste (CIBNOR). P.O. Box 128, La Paz, Baja California Sur. 23000. México; 2Universidad Autónoma de Baja California Sur. Carretera al Sur km. 5.5 o 23080 o La Paz, B. C. S.Algal diets have been evaluated and used extensively for the aquaculture of abalone, especially in Japan. In other areas little is known about the nutritional value of the algae that the local abalone consume. In Mexico, regional hatcheries use Macrocystis pyrifera as a main source of natural food. Kelp availability, year round, has not generally been a problem for abalone aquaculturists. Most difficulties occur during severe storms, which may prevent access to kelp beds. El Niño also caused widespread destruction of M. pyrifera. In this study, growth rates of juvenile green abalone Haliotis fulgens, 31.7 " 1.5 mm shell length and 2.5 " 0.2 g body weight were evaluated during 136 days. Juveniles were fed with some of the algae used in regional hatcheries, Macrocystis pyrifera, Egregia menziesii, Eisenia arborea, Porphyra sp. and Ulva sp. Shell length growth rates varied between 2 mm day‐1 for Ulva sp. and 18 mm day‐1 for M. pyrifera. Body weight rates ranged from no growth for Ulva sp. to 14 mg day‐1for E. menziesii. The percent of survival was between 46 and 75 %. Ulva sp. showed the lowest protein content followed by E. menziesii, E. arborea, M. pyrifera and Porphyra sp.

Enzymatic formation of (2 R)-hydroxy- and 2-oxo-hexadecanoic acid in Ulva pertusa and Porphyra sp.

(2 R)-Hydroxy-hexadecanoic acid and 2-oxo-hexadecanoic acid have been isolated for the first time from marine algae ( Ulva pertusa and Porphyra sp.). The two acids were shown to be formed enzymatically from palmitic acid (16:0) using [1- 13C]palmitic acid.

Effects of pH on the Conformation of Phycoerythrin from Nori Porphyra sp.

Phycoerythrin is one of the algal chromoproteins similar to phycocyanin, obtained from nori (red algae, Porphyra sp.) Pycocyanin is known to undergo a reversible self-dissociation-associa-tion reaction in the pH range from 5.4 to 6.8 in which phycoerythrin fails to do so. We investigated physicochemical properties of phycoerythrin further more in wide pH region to reveal the con-formational changes in the phycoerythrin molecule. Optical density, intrinsic viscosity [η], and sedimentation constants (s) of phycoerythrin were nearly unchanged in the pH 5-9, i.e. [η] was 2.3×10-2-3.7×10-2 (10-1 dm3/g) and s were 12-13S. At less than pH 5, the optical density at 280 nm, [η] and s were increased with decreasing pH. At more than pH 9, [η] tended to increase with increasing pH and a small component having 4.1S appeared at pH 9 and then only 3.0S component remained at pH 11. However, these small com-ponents disappeared and 12S component reappeared after dialysis against the pH 6.8 buffer solution. We conclude that phycoerythrin takes three forms depending on pH changes: a moderately expanded form beyond pH 9, an entangled or agregated form below pH 5 and a compact form be-tween pH 5 and 9. Moreover, 3S component is considered to be the product from a dissociation of the phycoerythrin hexamer having 13S.

Unsaturated fatty acids as antifungal substances effective against "akagusare" disease of the laver Porphyra sp.

The mechanism of recovering action of histidine on “akagusare” (red rot disease) of the laver Porphyra sp. was examined. Results showed that the antifungal effect against the responsible fungus Pytium porphyrae is not exerted directly by histidine, but is by some substances produced indirectly in the laver. The antifungal fraction was separated from the extracts of the recovering laver, by essentially the same methods as for phytoalexins from higher plants. The fraction conained almost exclusively unsaturated fatty acids, suggesting that the antifungal action observed is mostly attributed to those acids whose production is accelerated by added histidine.

Isolation and identification of antifungal substances from "akagusare"-infected laver Porphyra sp.

The antifungal substances effective against “akagusare”-infected Porphyra sp. were isolated by gas liquid chromatography equipped with a preparative apparatus. After being methylated, those substances were analyzed by gas chromatography-mass spectrometry. The data obtained, together with their infrared spectra, indicated that they are phenylacetic acid, unsaturated fatty acids such as octenoic, nonenoic, and nonedienoic acids, and saturated fatty acids such as nomnanoic and heptanoic acids. The antifungal substances in F-1 one of the organic acid fractions, showed much higher levels in the infected and the recovered laver than in the normal laver.

Erythrobacter longus gen. nov., sp. nov., an Aerobic Bacterium Which Contains Bacteriochlorophyll a

Four orange-pigmented and seven pink-pigmented strains of bacteria which contained bacteriochlorophyll a were isolated from high-tidal seaweeds, such as Enteromorpha linza (L.) J. Ag. and Porphyra sp. All of the isolates were gram negative. The orange-pigmented bacteria were rods with parallel sides and rounded ends, and the pink-pigmented bacteria were ovoids and short rods. All were motile by means of subpolar flagella. None of the strains produced growth anaerobically in the light. No growth occurred with an atmosphere containing H2 and CO2. All of these bacteria grew aerobically and utilized glucose, pyruvate, acetate, butyrate, and glutamate as sole organic carbon sources. The best growth occurred on complex media formulated for heterotrophic marine bacteria. Biotin was required. Oxidase and catalase were present. Small amounts of acid were produced from a wide range of carbohydrates under microaerobic conditions. Gelatin was hydrolyzed. The strains which we investigated fell into the following three clusters: cluster A, all of the orange strains; cluster B, three pink strains; and cluster C, four pink strains. The strains of clusters B and C required thiamine and nicotinic acid and were susceptible to streptomycin. Tween 80 was hydrolyzed and phosphatase activity was produced by the strains of clusters A and B. Pantothenate was required only by the strains of cluster C. The guanine-plus-cytosine contents of the deoxyribonucleic acids of these organisms ranged from 60 to 64 mol%. These organisms are recognized here as members of a new genus, Erythrobacter. Although these organisms did not grow phototrophically, the presence of bacteriochlorophyll a indicated that they are most closely related to the Rhodospirillaceae. The type species is Erythrobacter longus, the type strain of which is an orange strain, OCh101 (= IFO 14126).

アマノリの日周変化に関する生理的研究-I

Diurnal variation of cell size, photosynthesis, respiration and content of photosynthetic pigmenes in the thallus of porphyra sp. Were investigated in an artificial medium under 12-hour light (50, 000lx) and 12-hour dark cycles. Of these above mentioned four subjects under study, the first three showed similarly each of the diurnal rhythm characteristics. Cell size and photosynthesis exhibited their maxima toward the middle of the light period and minima in the middle of the dark period. Respiration gradually increased during the light period and tapered with the start of dark. The cell size of the younger thallus was generally smaller than that of older ones. Cell division in the former occurred over the whole thallus, while it was rather limited in the marginal parts in the latter. Content of photosynthetic poigments per dry weight or per area of the thallus was almost unchanged during the experimental period, except for some significant random changes in the content of phycoerythrin and phycocyanin.

LIGHT-INDUCED CHANGES IN ABSORBANCY AND FLUORESCENCE OF CHLOROPHYLLOUS PIGMENTS ASSOCIATED WITH THE PIGMENT SYSTEMS 1 AND 2 IN BLUE-GREEN ALGAE.

1. 1. The kinetics and the difference spectra of light-induced changes in absorbancy and of changes in the near infrared fluorescence were measured in the blue-green algae Schizothrix calcicola and Anacystis nidulans . 2. 2. The action spectrum of the photooxidation of P 700 in Schizothrix was measured in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea at 2°. 3. 3. The following quantum requirements q ( λ ), for actinic wavelength λ, were estimated for P 700 and cytochrome oxidation and for P 700 reduction. Schizothrix: P 700 oxidation, q (680 m μ ) varies between 2.0 and 2.6, and q (430 m μ ) between 5.6 and 6.4; cytochrome oxidation, q (680 m μ ) = 3.0−3.5; P 700 reduction, q (680 m μ ) = 3.0. Anacystis: cytochrome oxidation, q (680 m μ ) = 2.8. The requirements per quantum absorbed by the photochemical system responsible for the reaction will be lower. The results are not inconsistent with the assumption that the true quantum requirement for the photochemical transport of 1 electron is 1 for each of the two pigment systems. 4. 4. A new “differential” flow attachment for a fluorescence apparatus was constructed by means of which small changes in fluorescence could be measured with increased precision, because the noise due to actinic light was eliminated. 5. 5. In addition to the earlier observed light-induced changes in the fluorescence of chlorophyll a 2 , a relatively small light-induced increase in red fluorescence, excited by blue light, was observed in Schizothrix calcicola, Porphyridium cruentum and Porphyra sp. It was activated by Pigment System 1, was not reversed by light of System 2, and was not associated with redox changes of P 700. The difference spectrum of this fluorescence was different from that of chlorophyll a 2 , in having a higher hump at 720 mμ.