THERMAL ECOPHYSIOLOGY OF LAURENCIA PACIFICA AND LAURENCIA NIDIFICA (CERAMIALES,RHODOPHYTA) FROM TROPICAL AND WARM‐TEMPERATE REGIONS1

Laurencia is a globally distributed genus with about 80 species (order Ceramiales) that inhabit tropical, subtropical, and warm‐temperate regions of both sides of the Atlantic and Indo‐Pacific oceans. This study investigated how two species of Laurencia distributed in different thermal environments (California and Hawaii) varied in their photosynthetic responses to temperature. The thermal ecophysiology of both species was investigated at different temporal scales (short‐term responses and seasonal acclimatization) using oxygen evolution and pulse‐amplitude‐modulated (PAM) fluorometry. Our results indicated that seasonal acclimatization of both species of Laurencia influenced the short‐term photosynthetic response at both locations. Greater seasonal differences in the photosynthetic performance were observed for L. pacifica Kylin, which reflects the ability of this species to acclimatize to local environmental conditions characterized by short‐term fluctuations and a broader annual temperature range. Photosynthetic performance of L. nidifica J. Agardh was consistent with the less variable local environment (no short‐term fluctuations and a narrower temperature range). These results suggest that acclimatization to temperature variability in the environment can influence the degree of flexibility of physiological responses of species in this genus.     

Chemical variation in a new bromochamigrene derivative from the red seaweed Laurencia pacifica

The secondary metabolite chemistry of the red seaweed Laurencia pacifica Kylin varies geographically. The La Jolla, Calif. population (type locality) contains the sesquiterpene prepacifenol, while L. pacifica collected south of Ensenada, Mexico contains a new bromochamigrene derivative, the structure of which is described herein. Since chamigrene synthesis in Laurencia species has been demonstrated to be reasonably species-specific, L. pacifica may be a mixture of morphologically similar forms.     

CULTURE STUDIES ON THE RELATIONSHIP BETWEEN SCHIZYMENIA AND HAEMATOCELIS (GIGARTINALES,RHODOPHYCEAE) FROM THE PACIFIC COAST OF NORTH AMERICA1

Carpospores from Schizymenia pacifica (Kylin) Kylin (Gymnophlaeaceae) from California formed crusts anatomically identical to Haematocelis rubens J. Agardh (Cruoriaceae). Tetraspores of H. rubens from Monterey, California, and Baja California, Mexico, germinated to form basal discs from which arose upright multiaxial blades with a filamentous medulla and cortical gland cells. Pro-carps and spermatangia were present on the same blades; subsequently, cystocarps characteristic of Schizymenia pacifica developed. Re-examination of herbarium specimens suggests that the foliose tetrasporangial phases previously reported as S. pacifica are referable to Halymenia, Dilsea, Cryptonemia, or Turnerella. Schizymenia pacifica (type locality: San Juan Islands, Washington) thus is considered to be the gametophyte in the life history of Haematocelis rubens (type locality: Brest, France), which has also been reported to be the tetrasporophyte of S. dubyi (Chauvin ex Duby) J. Agardh (type locality: Cherbourg, France). Atlantic and Pacific gametophytes and tetrasporophytes are anatomically very similar, suggesting that only one species is involved, but critical studies must be made before a decision on this taxonomic question can be reached. Haematocelis zonalis Dawson et Neushul (type locality: Anacapa Island, California) is considered to be a growth form of the tetrasporangial phase of S. pacifica.     

DIFFERENT CHEMICAL TYPES OF PLOCAMIUM VIOLACEUM (RHODOPHYTA) FROM THE MONTEREY BAY REGION,CALIFORNIA1

Differences in the halogenated natural products of Plocamium violaceum Farlow can be noted from different sites in the Monterey Bay region, California. Specimens from the northern region produce a set of alicyclic halogenated monoterpenes which are not synthesized by those from the southern region. Instead, the latter elaborates a set of acyclic halogenated monoterpenes not observed from the former. This situation is invariant regardless of life history forms or different seasons. Similarly, the composition of halogenated monoterpene structures from P. cartilagineum (L.) Dixon varies at different locations. From the data presented herein we conclude that at least two chemical types can be identified for P. violaceum based upon differences in their halogenated products. Thus we suggest that the north Monterey form can be designated as chemotype α and the southern one as chemotype β.     

Brown algae (Phaeophyta) from Bahía de los Angeles,Gulf of California,México

Seven sites in Bahía de los Angeles, northern Gulf of California, were sampled seasonally over a three-year period. Five species of brown algae previously not recorded from this bay were identified: Ralfsia pacifica, Sporochnus balleanus, Hydroclathrus clathratus, Colpomenia sinuosa and Padina mexicana. Of these, H. clathratus also provided a new record for the northern Gulf of California. One species previously recorded from the bay, Dictyopteris undulata, was not observed. On a seasonal basis, temperature and biodiversity showed an inverse relationship: highest species numbers occurred in spring, when temperatures were lowest, and lowest species numbers occurred in autumn when temperatures were highest. Most species of brown algae in Baífa de los Angeles are annuals.     

Genetic diversity,endemism and phylogeny of lampreys within the genus Lampetra sensu stricto (Petromyzontiformes: Petromyzontidae) in western North America

Phylogenetic structure of four Lampetra species from the Pacific drainage of North America (western brook lamprey Lampetra richardsoni, Pacific brook lamprey Lampetra pacifica, river lamprey Lampetra ayresii and Kern brook lamprey Lampetra hubbsi) and unidentified Lampetra specimens (referred to as Lampetra sp.) from 36 locations was estimated using the mitochondrial cytochrome b gene. Maximum parsimony and Bayesian inferences did not correspond with any taxonomic scheme proposed to date. Rather, although L. richardsoni (from Alaska to California) and L. ayresii (from British Columbia to California) together constituted a well‐supported clade distinct from several genetically divergent Lampetra populations in Oregon and California, these two species were not reciprocally monophyletic. The genetically divergent populations included L. pacifica (from the Columbia River basin) and L. hubbsi (from the Kern River basin) and four Lampetra sp. populations in Oregon (Siuslaw River and Fourmile Creek) and California (Kelsey and Mark West Creeks). These four Lampetra sp. populations showed genetic divergence between 2·3 and 5·7% from any known species (and up to 8·0% from each other), and may represent morphologically cryptic and thus previously undescribed species. A fifth population (from Paynes Creek, California) may represent a range extension of L. hubbsi into the Upper Sacramento River.     

Morphology of Laurencia clavata and L. elata (Ceramiales,Rhodophyta) in relation to generic circumscription in the Laurencia complex

Laurencia Lamouroux (Rhodophyta) was recently separated into three genera–Laurencia, Chondrophycus (Tokida et Saito) Garbary et Harper and Osmundea Stackhouse – each of which was newly defined based on vegetative and reproductive structures. In this study, the previously unknown vegetative and reproductive morphology of two Australian endemic species of Laurencia, L. clavata Sonder and L. elata (C. Agardh) Harvey, was studied, particularly in the context of the revised generic delineation. These species exhibit vegetative axes with four pericentral cells and trichoblast-type spermatangial development. Tetrasporangia are abaxially produced from the existing third and fourth pericentral cells. L. clavata has terete thalli with distinctive verticillate branching and is similar to Chondria C. Agardh, rather than to Laurencia, in having an unusually marked constriction at the base of the branches and starch accumulation in subcortical and medullary cells. Compared to Laurencia, apical cells of this species exhibit a less oblique division ; the resulting recognizable axial cell rows extend somewhat below the branches, and particularly at a young stage they are also clear throughout branchlets. However, other vegetative and spermatangial structures show that L. clavata is more closely allied to Laurencia than to Chondria, and it is placed in Laurencia. By contrast, L. elata exhibits morphology typical of Laurencia and is characterized by large, robust, compressed thalli with fastigiately distichous branching and an extensive secondary cortex. Furthermore, it appears to be distinct from similar species in sometimes having a parasitic species of Janczewskia Solms-Laubach (Rhodophyta). Taxonomy of Laurencia is discussed on the basis of these and previous studies.     

An experimental approach to study the biosynthesis of brominated metabolites by the red algal genus Laurencia

The production of labeled brominated metabolites with radioactive ⁸²Br in Laurencia species was investigated as part of a study of the biosynthesis of halogenated metabolites from species belonging to the red algal genus Laurencia (Rhodomelaceae, Ceramiales). Radiobromide [⁸²Br], thin-layer chromatography (TLC), and TLC–autoradioluminography (ARLG) were used. When cultured in artificial seawater medium (ASP₁₂NTA including Na⁸²Br) under 16:8 h light:dark (LD) illumination cycles for 24 h, each of the strains of Laurencia, Laurencia japonensis Abe et Masuda, Laurencia nipponica Yamada (laurencin-producing race and laureatin-producing race), and Laurencia okamurae Yamada, produced species- (or race-) specific ⁸²Br-containing metabolites. In the case of the laurencin-producing race of L. nipponica, laurencin and deacetyllaurencin were found to be produced in approximately 1:1 ratio, though laurencin is the major metabolite in the wild sample. Furthermore, when cultured in the dark, the production rates of brominated metabolites in Laurencia spp. were found to be diminished. The present study strongly indicates that the use of radiobromine [⁸²Br] in combination with the TLC–ARLG method is an effective approach for investigating the biosynthesis of brominated metabolites in Laurencia.     

Chemical relationship between red algae genus Laurencia and sea hare (Aplysia dactylomela Rang) in the North Borneo Island

Red algae genus Laurencia is an interesting alga with the ability to produce halogenated secondary metabolites that exhibits ecological and pharmaceutical potential. In nature, Laurencia is selectively grazed by sea hares (Aplysia dactylomela). In this study, Laurencia populations in three islands (Mantanani, Sulug, and Dinawan Islands) in the coastal waters of North Borneo were investigated and their chemical relationship with sea hare determined. Four species of Laurencia were found to grow abundantly in these waters, Laurencia snackeyi, Laurencia majuscula, Laurencia nangii, and Laurencia similis. Sea hares, Aplysia dactylomela, found grazing on Laurencia were collected and their chemical composition determined. A total of 20 halogenated metabolites were isolated and identified via spectroscopic data. Isolated compounds could be grouped into syndrean (5), chamigrane (6), non-chamigrane sesquiterpene (3), cuparane (1), bromoindole (2), and C15 acetogenin (acetylene type) (3). Sea hares from Mantanani, Sulug, and Dinawan Islands contained a total of 9, 10, and 10 compounds, respectively. In addition, 12-acetoxypalisadin B (1), which was isolated from sea hares of Sulug Island is a first record of its existence in nature.     

PHYLOGEOGRAPHY OF THE SPOTTED SAND BASS, PARALABRAX MACULATOFASCIATUS: DIVERGENCE OF GULF OF CALIFORNIA AND PACIFIC COAST POPULATIONS

Abstract Have the warm tropical waters and currents of the southern Gulf of California, Mexico (also known as the Sea of Cortez), formed a barrier to gene flow, resulting in disjunct populations in the upper gulf that are isolated from the outer Pacific Coast? Phylogeographic and genetic divergences of the spotted sand bass, Paralabrax maculatofasciatus, from three Gulf of California and two outer Pacific coastal locations were tested using mitochondrial DNA (mtDNA) control region sequences. Sequence data from two congeners that are sympatrically distributed along the outer Pacific Coast, the barred sand bass, P. nebulifer, and the kelp bass, P. clathratus, were used to gauge the levels of genetic divergences. Differences among the three species and between the northern gulf and outer Pacific coastal populations of P. maculatofasciatus also were analyzed using 40 allozymic presumptive gene loci. Allozyme and mtDNA analyses each revealed many fixed differences among the species. Three significant allozymic frequency differences and two fixed mtDNA substitutions differentiated the gulf and outer Pacific coastal populations of P. maculatofasciatus. Three unique mtDNA haplotypes and three unique allozyme alleles were identified from the outer Pacific coastal population. The gulf sites contained four unique mtDNA haplotypes and six unique allozyme alleles. Partitioning of the mtDNA variation revealed that 72% of the variance occurred between the gulf and outer Pacific Coast, 20% between sampling sites in the two regions, and 8% within the sites. There appears to be little gene flow across the waters of the southern Baja Penninsula, producing divergence estimated as 120,000 to 600,000 years between the outer Pacific coastal and the Gulf of California populations. This separation level may date to a hypothesized seaway closure near La Paz, Mexico, during the mid‐Pleistocene, and characterizes other fish populations. A second pattern of deeper allopatric species‐level divergences in some other fishes may date to a Pliocene closure of a mid‐Baja Penninsular seaway. Significant differences also were discerned in P. maculatofasciatus between the San Diego and central Baja California coastal sites and between the upper/central and the lower gulf locations. Variation between locations in the two regions may be indicative of larval retention and low adult migration, which needs to be tested further.     

Additional analysis of chemical diversity of the red algal genus Laurencia (Rhodomelaceae) from Japan

The halogenated secondary metabolite constitution of four species of the red algal genus Laurencia (Rhodomelaceae) from southern Japan is reported. Laurencia composita Yamada from Tanegashima Island (Kagoshima Prefecture) bears five sesquiterpenoids (2,10‐dibromo‐3‐chloro‐α‐chamigrene and 2,10‐dibromo‐3‐chloro‐9‐hydroxy‐α‐chamigrene, in addition to pre‐pacifenol epoxide, johnstonol and pacifenol, which are known in other populations of this species). Laurencia intricata Lamouroux from Chinzei (Saga Prefecture) and Oomura Bay (Nagasaki Prefecture) bear a C₁₅ aceto‐genin, okamurallene. Laurencia majuscula (Harvey) Lucas from Tanegashima Island produces three sesquiterpenoids, (Z)‐10,15‐dibromo‐9‐hydroxy‐chamigra‐1, 3(15),7(14)‐triene, 10‐bromo‐7‐hydroxylaurene and 10,11‐dibromo‐7‐hydroxylaurene, corresponding to those of one of its chemical races. Laurencia venusta Yamada from Tanegashima Island produces two sesquiterpenoids, cupalaurenol and cyclolaurenol, which were known only from a sea hare, Aplysia dactylomela Rang. This strongly suggests that Aplysia consumes L. venusta and concentrates these halogenated compounds.     

LAURENCIA MARILZAE SP. NOV. (CERAMIALES,RHODOPHYTA) FROM THE CANARY ISLANDS,SPAIN, BASED ON MORPHOLOGICAL AND MOLECULAR EVIDENCE1

Laurencia marilzae Gil‐Rodríguez, Sentíes et M.T. Fujii sp. nov. is described based on specimens that have been collected from the Canary Islands. This new species is characterized by distinctive yellow–orange as its natural habitat color, a terete thallus, four pericentral cells per vegetative axial segment, presence of secondary pit‐connections between adjacent cortical cells, markedly projecting cortical cells, and also by the presence of corps en cerise (one per cell) present in all cells of the thallus (cortical, medullary, including pericentral and axial cells, and trichoblasts). It also has a procarp‐bearing segment with five pericentral cells and tetrasporangia that are produced from the third and fourth pericentral cells, which are arranged in a parallel manner in relation to fertile branchlets. The phylogenetic position of this taxon was inferred based on chloroplast‐encoded rbcL gene sequence analyses. Within the Laurencia assemblage, L. marilzae formed a distinctive lineage sister to all other Laurencia species analyzed. Previously, a large number of unique diterpenes dactylomelane derivatives were isolated and identified from this taxon. L. marilzae is morphologically, genetically, and chemically distinct from all other related species of the Laurencia complex described.     

Antifouling Brominated Diterpenoids from Japanese Marine Red Alga Laurencia venusta Yamada

The marine red algal genus Laurencia has abundant halogenated secondary metabolites, which exhibit novel structural types and possess various unique biological potentials, including antifouling activity. In this study, we report the isolation, structure elucidation, and antifouling activities of two novel brominated diterpenoids, aplysin-20 aldehyde ( 1 ), 13-dehydroxyisoaplysin-20 ( 2 ), and its congeners. We screened marine red alga Laurencia venusta Yamada for their antifouling activity against the mussel Mytilus galloprovincialis. Ethyl acetate extracts of L. venusta from Hiroshima and Chiba, Japan, were isolated and purified, and the compound structures were identified using 1D and 2D NMR, HR-APCI-MS, IR, and chemical synthesis. Seven secondary metabolites were identified, and their antifouling activities were evaluated. Compounds 1 , 2 , and aplysin-20 ( 3 ) exhibited strong activities against M. galloprovincialis. Therefore, these compounds can be explored as natural antifouling drugs.     

CLASSIFICATION OF THE GENUS ISHIGE (ISHIGEALES,PHAEOPHYCEAE) IN THE NORTH PACIFIC OCEAN WITH RECOGNITION OF ISHIGE FOLIACEA BASED ON PLASTID rbcl AND MITOCHONDRIAL cox3 GENE SEQUENCES1

The taxonomy and biogeography of a genus with species that occur in geographically isolated regions is interesting. The brown algal genus Ishige Yendo is a good example, with species that apparently inhabit warm regions of both the northwestern and northeastern Pacific Ocean. We determined the sequences of mitochondrial cox3 and plastid rbcL genes from specimens of the genus collected over its distributional range. Analyses of the 86 cox3 and 97 rbcL sequences resulted in congruent trees in which Ishige sinicola (Setch. et N. L. Gardner) Chihara consisted of two distinct clades: one comprising samples from Korea and Japan, and the other comprising samples from the Gulf of California. Additional observations of the morphology and anatomy of the specimens agree with the molecular data. On the basis of results, we reinstated Ishige foliacea S. Okamura (considered a synonym of I. sinicola from the Gulf of California) for plants from the northwest Pacific region and designated a specimen in the Yendo Herbarium (SAP) as the lectotype. I. foliacea is distinguished by large (up to 20 cm) and wide (up to 20 mm) thalli, with a cortex of 4–7 cells, and a medulla composed of long, tangled hyphal cells. Both cox3 and rbcL sequence data strongly support the sister‐area relationship between the northwest Pacific region and the Gulf of California. A likely explanation for this pattern would be the presence of a species ancestral to contemporary species of Ishige in both regions during the paleogeological period, with descendants later isolated by distance.     

Nonhalogenated organic molecules from Laurencia algae

The marine red algae of the genus Laurencia have produced more 700 secondary metabolites and exhibited high molecular diversity and intriguing bioactivity. Since the halogenated structures have been comprehensively reviewed previously, this review, covering up to the end of 2012, mainly focuses on the source, structure elucidation, and bioactivity of nonhalogenated organic molecules from Laurencia spp. as well as the relationship between nonhalogenated and halogenated products. Overall, 173 new or new naturally occurring compounds with 58 skeletons, mainly including sesquiterpenes, diterpenes, triterpenes, and C₁₅-acetogenins, are described.     

Brominated metabolites from an Okinawan Laurencia intricata

Two halogenated C₁₅ acetogenins, itomanallenes A and B, with a terminal bromoallene moiety along with a halogenated sesquiterpene, itomanol, have been isolated from the red alga Laurencia intricata collected in Okinawan waters. Their structures were deduced from 1D and 2D NMR experiments including ¹H–¹H COSY, HSQC, HMBC, and NOESY methods. The alcohol corresponding to itomanallene B seems to be a plausible precursor of itomanallene A, which has an unusual 2,10-dioxabicyclo[7.3.0]dodecene skeleton. Itomanol was found to be a selinane-type bromosesquiterpenoid, and is the first example of a selinane to be isolated from Japanese Laurencia species.     

A rearranged chamigrene derivative and its potential biogenetic precursor from a new species of the marine red algal genus Laurencia (rhodomelaceae)

The structures of a novel rearranged sesquiterpenoid and a biogenetically-related chamigrene derivative have been determined by combined spectral and chemical methods. These sesquiterpenoids were components of an undescribed Laurencia species, and each was toxic toward the damselfish Pomacentrus coeruleus.     

Structural diversity and geographical distribution of halogenated secondary metabolites in red algae,Laurencia nangii Masuda (Rhodomelaceae,Ceramiales), in the coastal waters of North Borneo Island

The red algae genus Laurencia (Rhodomelaceae, Ceramiales) is known as a prolific producer of halogenated secondary metabolites with a high level of species diversity and geographical distribution. In North Borneo Island, Malaysia, there are four main Laurencia species: Laurencia snackeyi, Laurencia majuscula, Laurencia similis and L. nangii. Although the chemistry of Laurencia is well studied, the diversity of compounds in L. nangii has not been thoroughly investigated. Therefore, we studied the chemical constituents of seven populations of L. nangii from Tunku Abdul Rahman Marine Park (two populations), Dinawan Island (one population), Tun Mustapha Marine Park (two populations) and Tun Sakaran Marine Park (two populations). Halogenated compounds were isolated and the structures determined via spectroscopic methods. A total of 20 metabolites belonging to the classes of sesquiterpenes, acetylenes, bromoallenes, diterpenes and triterpenes were identified. Populations from Tunku Abdul Rahman Marine Park and Dinawan Island contained non-chamigrane-type sesquiterpenes, acetylenes and diterpenes. Populations from Tun Mustapha Marine Park contained chamigrane-type sesquiterpenes, acetylenes and diterpenes. However, the chemical compositions of populations from Tun Sakaran Marine Park were found to differ significantly, containing chamigrane-type and non-chamigrane-type sesquiterpenes, bromoallenes and triterpenes. This investigation has revealed the presence of interesting chemotaxonomical markers in populations of L. nangii and the existence of chemical races in this species.     

STUDIES IN SOME FOLIOSE RED ALGAE OF THE PACIFIC COAST. III. DUMONTIACEAE,WEEKSIACEAE, KALLYMENIACEAE1

The female reproductive structures and their development, and the vegetative structure are studied in 17 species of red algae in the Cryptonemiales (Rhodophyceae). Three genera, Weeksia, Constantinea, and the type species of Leptocladia, are removed from the Dumontiaceae to a newly created family, the Weeksiaceae, because of differing postfertilization events leading to the development of the gonimoblast from a cell of the carpogonial branch. Three genera of Dumontiaceae are studied: Pikea, including P. californica, the type species, and Pikea robusta a newly described species; Dilsea californica, and a newly described species of Neodilsea, a genus heretofore known only from the northwestern Pacific. Two transfers are made from the genus Leptocladia, 1 to Farlowia, as F. conferta, and 1 to Rhodophyllis (Gigartinales) as R. peruviana. Three species in the Kallymeniaceae are redescribed: Kallymenia pacifica, a rare and nearly unknown species from southern California and adjacent Pacific Mexico; K. norrisii from central California; and K. oblongifructa from Washington, Oregon, and northern California.