Actin-mediated chloroplast movement in Griffithsia pacifica (Ceramiales, Rhodophyta)

Chloroplast banding occurs in Griffithsia pacifies Kylin in a daily rhythm. At the start of the light period, chloroplasts have a uniform distribution. During the light period chloroplasts move away from the ends of the cell leaving two chloroplast-free regions by mid-afternoon. Later in the light period these bands disperse as chloroplasts return to the ends of cell where they remain throughout the dark period. After enzyme treatment with β-glucuronidase to permeabilize cell walls, non-banded plants did not form bands after the addition of 5 μg ml^?1 cytochalasin B in dimethyl sulfoxide (DMSO). When enzyme-grown plants with chloroplast bands were treated with cytochalasin B, bands were retained for at least three days. Plants grown in media supplemented with β-glucuronidase or DMSO alone gave banding consistent with untreated controls. Staining of microfilaments with rhodamine-phalloidin before and after treatment with cytochalasin B gave results consistent with chloroplast movement studies. This is the first report of actin-mediated organelle movement in red algae.     

Additional analysis of chemical diversity in Laurencia nipponica (Ceramiales, Rhodophyta)

The red alga Laurencia nipponica Yamada (Rhodomelaceae, Ceramiales) is known to contain several chemical races, each of which is characterized by a particular, major halogenated secondary metabolite. Both field-collected and cultured plants of a population of this species found recently at Shikanoshima Island, Fukuoka Prefecture, southern Japan, produced C₁₅ bromoethers, (3E)-laureatin and (3E)-isolaureatin, and sesquiterpenoids, 2,10-dibromo-3-chloro-9-hydroxy-α-chamigrene and 2,10-dibromo-3-chloro-α-chamigrene. Laurencia nipponica can be referred to as a further chemical race that is characterized by the production of two C₁₅ bromoethers, (3E)-laureatin and (3E)-isolaureatin, and a sesquiterpenoid, 2,10-dibromo-3-chloro-9-hydroxy-α-chamigrene as major compounds.     

Changes in the Expression of β and Actins During Differentiation of PC 12 Cells

Cells of the rat pheochromocytoma line PC12 cease proliferation and develop neurites in response to nerve growth factor (NGF). Quantification of beta and gamma isoforms of nonmuscle actin in extracts of these differentiating cells showed that the beta:gamma ratio decreased from 1.30 +/- 0.05 to 0.99 +/- 0.05 after 6 days of NGF treatment. Cells treated with N6,O2-dibutyryl cyclic AMP (dbcAMP) also showed a shift in the ratio of beta:gamma isoforms, although few of these cells extended neurites. Administration of dbcAMP or both NGF and dbcAMP to cells accelerated the decrease in the beta:gamma actin isoform ratio relative to treatment with NGF alone. Those cells treated with both NGF and dbcAMP also showed an accelerated rate of neurite outgrowth. Suspension-grown PC12 cells treated with NGF showed neither an isoform ratio decrease nor neurite development. Our results suggest that either cyclic AMP may be a "second messenger" for NGF or it may effect the isoform ratio change by an independent mechanism. In addition, our data demonstrate an alteration in actin isoform expression, which accompanies the morphological differentiation of PC12 cells.     

The reproductive structures of the Mediterranean alga Laurencia pelagosae (Ceramiales,Rhodophyta)

Reproductive structures of Laurencia pelagosae are described for the first time. Tetrasporangia, in parallel arrangement, are cut off from the mother cells adaxially; antheridial branches, which are unramified, are inserted in depressions lacking a row of axial cells on their bases; cystocarps are sessile and subspherical. The occurrence of secondary pit-connections between epidermal cells and of lenticular thickenings in the walls of medullary cells is documented. The species is included in the new section Pelagosae within the subgenus Laurencia.     

Mastophoropsis canaliculata (Harvey in Hooker) gen. et comb. nov. (Corallinaceae,Rhodophyta) in Southern Australia

Mastophoropsis canaliculata (Harvey in Hooker) gen. et comb. nov. (Corallinaceae, Rhodophyta) is restricted to south-eastern Australian waters. It is unique among Corallinaceae in possessing an erect, tenacular, branched, taeniform, non-geniculate thallus which produces multiporate tetrasporangial conceptacles. Based on a detailed morphological and anatomical study, including an examination of the designated lectotype, this taxon is referred to the tribe Phymatolitheae in the subfamily Melobesioideae and its relationships to other non-geniculate Corallinaceae are discussed. A simplified microtechnique procedure involving decalcification with nitric acid, resin embedding and staining serially mounted sections with KMnO₄ also is outlined. X-ray microanalysis of surface tissues indicates that calcification occurs largely as CaCO₃ and that various structures contain substantially differing amounts of Ca.     

Isolation of a cDNA encoding a homologue of actin from Porphyra yezoensis (Rhodophyta)

We report the nucleotide sequence of a cDNA encoding an actin from amarine red alga, Porphyra yezoensis Ueda. A cDNA clone wasisolated from a leafy gametophyte cDNA library and analyzed for the sequence.The clone contained an open reading frame for a protein of 373 amino acidswhichexhibits sequence similarity to known actins. The GC content of the thirdposition (83.9%) was much higher than that at the first (56.3%) and second(42.4%) positions. The actin forms a gene family in the P.yezoensis genome. Comparison of the deduced amino acid sequenceshowed higher similarity to the Florideophycidae Chondruscrispus (85%) than to the ProtoflorideophycidaeCyanidioschyzon merolae (70%). The mRNA was detected inboth the leafy gametophytes and filamentous sporophytes. The nucleotidesequence data reported in this paper will appear in theDDBJ/EMBL/GenBank databases under accession number AB039831.     

The morphology and taxonomy of Womersleya monanthos, an endemic species and genus of Delesseriaceae (Ceramiales, Rhodophyta) from southeastern Australia

Womersleya monanthos (J. Agardh) Papenfuss is typically an epiphyte of larger brown and red algae that are common in drift along the southeastern coasts of Australia. A hitherto little-known member of the Phycodrys group of the Nitophylloideae, its reproductive features have been studied in detail and its taxonomic position clarified. Blades are polystromatic throughout and lack veins or nerves, with blades originating from apical cells of primary and second-order cell rows. Intercalary cell divisions take place in primary cell rows and all other branch orders, with third-order laterals arising both abaxially and adaxially on cells of second-order rows. Fertile central cells bear procarps on pericentral cells on both sides of the blade, the procarps consisting of two 4-celled carpogonial branches and a single central group of sterile cells that enlarge and persist at the distal end of a bicampanulate fusion cell at maturity. Spermatangia and tetrasporangia form in circular subapical sori on both sides of the blade or in marginal lobes or proliferations. After comparing it to other members of the Phycodrys group, we conclude that Womersleya is a monotypic genus well distinguished from other genera and with probable closest affinities to the Northern Hemisphere Polyneura, Erythroglossum and Sorella, as well as the Australian endemic, Crassilingua.     

Morphological and random amplified polymorphic DNA features in populations ofCeramium kondoi (Rhodophyta)

Morphological and RAPD features ofCeramium kondoi populations were investigated and compared in different locations in Korea. The plant length and branching pattern were more variable in Jindo population than others. RAPD data showed thatC. kondoi plants were divided into two clades; the southern group including Jindo and Bangpo population, and the northern group including Yonpyongdo and Oeyondo population. Morphological features inC. kondoi populations corresponded with RAPD data, which differed from those ofC. boydenii from the same location. These results suggest that RAPD might be useful for elucidating genetic variation among the wild populations ofC. kondoi.     

Developmental morphology of Odonthalia floccosa (Ceramiales, Rhodophyta) in laboratory culture

Material of the red alga Odonthalia floccosa (Esper) Fal-kenberg (Rhodomelaceae, Ceramiales), collected from California, was cultured in the laboratory and its life-history was completed. Tetraspores grew into bipolar sporelings that differentiated into a colorless rhizoidal portion and a pigmented upright shoot. The sporelings became compressed apically and formed lateral branches in a regularly distichous manner that were congenitally fused with the main axis. These tetraspore germlings grew into diecious gametophytes. Male ga-metophytes produced numerous spermatangia on modified fertile branchlets (male trichoblasts) that possessed three to four monosiphonous, proximal segments. Female gametophytes formed a single pro-carp on the suprabasal segment of unbranched female trichoblasts. Cystocarps developed on the female gametophytes cocultured with male gametophytes and released viable carpospores that developed into fertile te-trasporophytes. Tetrasporangia were produced from the third and fourth periaxial cells in each of 12–45 successive fertile segments and provided three (two lateral and one basal) cover cells. The occurrence of both spermatangia and procarps on fertile trichoblasts in O. floccosa suggests that the alga is the most derived in these two characters among the species of the genus Odonthalia. This species is distributed in cold temperate regions in the North Pacific, and it should be excluded from the North Atlantic marine algal flora.     

Growth of the conchocelis phase of Porphyra columbina (Bangiales, Rhodophyta) at different temperatures and levels of light, nitrogen and phosphorus

Temperature, light, nitrogen and phosphorus all had significant effects on the growth of conchocelis colonies of Porphyra columbina Montagne when grown in vitro using a shell substrate. High rates of growth were recorded at 15°C and at 8°C under low light levels. These fight and temperature conditions are similar to those found in the subtidal environment of southern New Zealand coastlines. Little growth occured at 22°C. Nitrogen stimulated growth at concentrations far greater than are likely to be found in situ, while at concentrations of 120 μmol/L and above phosphorus had an inhibitory effect on growth, The culture parameters were strongly interactive in their effect on growth, in particular temperature and light. Conchosporangia formed in all treatments 14 days after alteration of the photoperiod to 10 h light: 14 h dark. Optimal conditions for culture of the conchocelis of P. columbina from southern New Zealand are a water temperature of approximately 15°C, light levels between 10 and 50 μmol m^?2s^?1 and seawater nitrogen levels maintained above 100 μmol/L.     

Porphyra aeodis sp. nov. (Bangiales,Rhodophyta), an epiphyte of Aeodes orbitosa from South Africa

A new species of Porphyra is described from the south western Cape, South Africa. The gametophyte of Porphyra aeodis sp. nov. grows epiphytically on Aeodes orbitosa (Suhr) Schmitz, and has a seasonal life history that matches that of its host. Although P. aeodis has been confused with P. capensis Kützing in the past, P. aeodis is more similar to the sympatric but epilithic P. saldanhae Stegenga, Bolton et Anderson. There is considerable morphological overlap between P. aeodis and P. saldanhae, although they may be distinguished using a combination of morphological and ecological characters. The taxonomic separation of P. aeodis and P. saldanhae was confirmed using isozyme electrophoresis.     

Life history in culture of the obligate epiphyte Porphyra subtumens (Bangiales, Rhodophyta) endemic to New Zealand

This is the first report of the growth in culture of Porphyra subtumens J. Agardh ex Laing (Bangiales, Rhodophyta), an obligate epiphyte of Durvillaea species and endemic to New Zealand waters. Archeospores, previously observed on field material, develop directly into the blade phase. Spores released from field collected blades form conchocelis. Conchospores develop into new blades, completing the life history in culture. Earlier reports of reproduction in P. subtumens gave conflicting accounts with some authors citing this species as having an asexual, monophasic life history with an unusual form of spore production, while others described spermatangia and carposporangia on the blade phase.     

Porphyra monospore system (Bangiales, Rhodophyta): A model for the developmental biology of marine plants

We have developed an experimental system of cohort monospores from clonal culture of leafy gametophytes in Porphyra yezoensis Ueda (strain TU-1). This system is quite different from traditional systems for algal protoplast experimentation, which require expensive enzymatic treatment and utilize an ineffective method of preservation. Cohort monospores were obtained by utilizing a mode of asexual reproduction in the culture strain (monospores) and artificial regulation (thallus length, temperature, light, etc.) of monospore release. When the leafy gametophytes that formed monospores were frozen at - 20°C in a cryoprotective solution composed of 5% DMSO and 5% dextran in 100% seawater, about 98% survived for 3 months. When stored at 5°C without cryoprotectants, these leafy gametophytes could be kept without monospore release for 1 week. Maximum monospore yield was about 3000 spores per 100 gametophytes, and germination rate was about 70%, This system will accelerate developmental biology studies in Porphyra.     

The cell wall chemistry of Bangia atropurpurea (Bangiales, Rhodophyta) and Bostrychia moritziana (Ceramiales, Rhodophyta) from marine and freshwater environments

The cell wall polysaccharides of two species of red algae, which are adapted to both freshwater and marine environments, were analysed to determine the effect of these widely different environments on their commercially important agarocolloids and to investigate the possible role of the cell wall in environmental adaptation. Cell wall polymers of freshwater isolates of Bangia atropurpurea (Roth) C. Agardh and cultured freshwater and marine Bostrychia moritziana (Sonder ex Kützing) J. Agardh were isolated and the polysaccharides chemically fractionated and characterized. Wall polysaccharides of freshwater B. atropurpurea were similar to those previously reported for marine isolates with repeating disac-charide units of agarose and porphyran predominant in the hot water extracts. In the insoluble residues, 3-iinked galactosyl and 4-linked mannosyl residues were predominant. Bostrychia moritziana wall polysaccharides included agarocolloids with various patterns of methyl ether substitution similar to those previously described for other Ceramiales. Differences in the position of methyl ether substituents were detected in the hot water extracts of the freshwater and marine specimens. Polymers of freshwater ß. moritziana cultures were composed of a complex mixture of repeating disaccharide units including 2′-O-methyl agarose, 6-O-methyI agarose and 2′-O-methyl porphyran. Polymers of marine isolates of ß. moritziana differ in that they contain only trace amounts of 2-O-methyl saccharides and increased amounts of 6-O-amethyl saccharides. The hot water insoluble residues of both freshwater and marine isolates of ß. moritziana contain a mixture of 3-linked galactosyl and 4-linked glucosyl residues. These results indicate that the adaptive response of B. moritziana to changing osmotic and ionic conditions may include changes in cell wall chemistry: notably, the pattern of methyl ether substitution.     

Fusion and histocompatibility in Rhodophyta

Fully developed thalli of Chondrus crispus, Gracilaria chilensis, Gymnogongrus furcellatus and Mazzaella laminarioides were used to assess tissue compatibility. The effect of thallus polarity on grafting and regeneration was also evaluated. Fusion did occur between fragments of the same life history phase in C. crispus, G. chilensis, G. furcellatus and M. laminarioides. Fusion between sporophytic and gametophytic tissue occurred in C. crispus, G. chilensis and M. laminarioides. Intergeneric fusion was observed between C. crispus and M. laminarioides, but not between G. chilensis and G. furcellatus.Outer cell wall, cortex and medulla were continuous at the contact face in compatible combinations. Medullary cells in the attached fragments were thinner and longer than normal cells, forming an interwoven scar plate. Thallus polarity did not modify fusion and regeneration.     

Porphyra lilliputiana sp. nov. (Bangiales, Rhodophyta): A diminutive New Zealand endemic with novel reproductive biology

A new species of Porphyra, Porphyra lilliputiana, is described for the New Zealand region. This species is very small ([5] 10–20 [35] mm) and is found growing epiphytically, epilithically and epizoically on upper inter-tidal shores of moderate exposure. Field-collected material of P. lilliputiana possessed archeosporangia, endosporangia, spermatangia and zygotosporangia. In culture, archeospores vi/ere released and germinated to form thalli. Endosporangia either developed directly into thalli or released endospores which individually formed thalli. Zygotospores developed into the concho-celis phase, which formed conchosporangia. Released conchospores formed thalli. This species is distinguished by its small size, arrangement of reproductive cells, occurrence of endosporangia, dentate margin and habitat.     

A new species of Laurencia, L. omaezakiana (Ceramiales, Rhodophyta), from Japan

Laurencia omaezakiana Masuda, sp. nov. (Ceramiales, Rhodophyta) is described from Japan. It is characterized by the following set of features: (i) the production of four periaxial cells from each vegetative axial cell; (ii) a shift in branching from distichous to spiral; (iii) the presence of projecting superficial cortical cells near the apices of branches; (iv) the presence of longitudinally oriented secondary pit-connections between contiguous superficial cortical cells; (v) the presence of lenticular thickenings in the walls of medullary cells; (vi) the occurrence of 1–2 corps en cerise in each superficial cortical cell and a single corps en cerise in each trichoblast cell; and (vii) a parallel arrangement of tetrasporangia. Furthermore, it produces a characteristic triterpenoid (enshuol), which has not been detected in other species of Laurencia, as a major halogenated secondary metabolite. A synoptical key to the 23 species of Laurencia growing in Japan is given. Laurencia ceytanica J, Agardh and Laurencia heteroclada Harvey are excluded from the Japanese marine algalflora. The latter is a distinct species from Laurencia filiformis (C. Agardh) Montagne.     

Molecular divergence of the ssu rRNA gene and internal transcribed spacer 1 in Porphyra yezoensis (Rhodophyta)

Nucleotide sequences from the downstream of ssu rDNA to ITS1 region of the individual thalli of both wild-collected Porphyra yezoensis from three different sites and culture strains were determined to obtain the molecular features of strains in the P. yezoensis lineage. Wild-collected thalli identified by morphological systematics, included the individuals that were separate from the P. yezoensis lineage based on ssu rDNA and ITS1 sequence homologies and phylogenetic relationships constructed using ITS1 sequences. Ssu rDNA exon region nucleotide sequences were identical among the wild-collected and clture strains of P. yezoensis. However, all individual wild-collected P. yezoensis thalli had different ITS1 sequences, even among individuals from the same sites. Furthermore, two different ssu rDNA structures with and without an intron were found in individuals from the same site. These results indicated the possibility that the presence and sequence of introns and ITS1 sequences can be used as a characteristic to determine the origin of culture strains. Four of six culture strains examined had an identical sequence from the ssu rDNA to ITS1, while the sequences of another two strains differed. In this study, wild-collected and culture strain thalli sequences were not identical, although similar pairs were identified. This revised version was published online in July 2006 with corrections to the Cover Date.