bluuebunny/crossref_metadata_2025 huggingface dataset:
95  Development of macroalgal (seaweed) taxonomic keys utilizing digital & media technology
Authors: Lehman R. L. , Albert E. M.
Published: January 2004

Digital, user‐friendly seaweed identification keys and instructional materials can provide information that allows students and researchers to enhance and improve marine field and ecological studies by including macroalgae. In much of the scientific literature, the seaweeds are only characterized to division (red, green, and brown), sometimes to genus, and very rarely to species; so there is clearly a need for a reference that facilitates the identification of the seaweeds. Many of the problems occur because of the lack of user‐friendly identification keys. However, it is not necessary to be an expert to identify seaweeds as many of the key characteristics used in their identification can be ascertained with the naked eye, a hand lens and an inexpensive microscope. What is needed is an identification guide that uses and displays important characters and identification structures visually (both macroscopic and microscopic) so that research scientists, students, teachers and the general public will be able to identify the seaweeds with confidence. We are using Lucid Professional software to construct digital keys for the identification of macroalgae from the Texas Coastal Bend. The advantages include: 1) key characters along with descriptions and images for specific macroalgae may be chosen from a geographic area of choice, 2) the user may evaluate the characters in any order and difficult or uncertain characters may be ignored, 3) descriptive pages of images, definitions, video clips and illustrations may be included for each taxon, and 4) the key can be displayed as a website or packaged as a CD to be used with laptop computers in the field.
96  Recognizing cryptic species: investigations into the molecular relatedness and morphological diversity of the species of the red algal genus plocamium (plocamiales, florideophyceae)
Authors: Lehmkuhl K. V. , Saunders G. W.
Published: January 2004

Small‐subunit ribosomal DNA (SSU) sequences used in combination with anatomical and morphological data have supported elevation of the Plocamiaceae to ordinal status. The Plocamiales currently includes two genera: the free‐living Plocamium Lamouroux; and the adelphoparasite, Plocamiocolax Setchell. Plocamium includes upwards of 40 species, which are widely distributed throughout the world's oceans. Most species are clearly defined anatomically and biogeographically. In this regard the type species, P. cartilagineum (L.) Dixon (type locality: reportedly Northern Europe), is an exception. Plocamium cartilagineum is considered cosmopolitan in distribution, with individuals varying in size, and in the number and habit of ramuli in their alternating series. We have sequenced the large‐subunit ribosomal DNA (LSU) for representatives of P. cartilagineum from France, Ireland, Norway and Scotland as well as isolates from Australia and the North Pacific. These data indicate that many cryptic species, four within Europe itself, are currently included within the concept of P. cartilagineum. We present molecular, biogeographical, ecological, and morphological/anatomical data characterizing these European forms and provide taxonomic revisions that reflect this diversity within P. cartilagineum.
97  Sensitivity of cyanobacteria to a potential biological control agent, bacterium SG‐3
Authors: Wilkinson K. , Walke H. L. , Lembi C.
Published: January 2004

Cyanobacteria cause many problems in freshwater ecosystems. For example, the production of off‐flavor compounds by cyanobacteria causes serious problems in catfish aquaculture. Control of cyanobacteria is generally limited to treatment with copper compounds, which are non‐selective and sometimes ineffective at controlling certain species of cyanobacteria. Biological control could provide selective management by removing unwanted species while leaving desirable algae species. A bacterium (SG‐3) (NRRL B‐30043) lyses a number of planktonic species of cyanobacteria including bloom‐forming species of Anabaena and Oscillatoria. We tested SG‐3 for activity against 10 isolates, representing seven species, of mat‐forming cyanobacteria within the genera Oscillatoria, Lyngbya, and Phormidium. Plugs (0.5 cm diameter) were cut from mats of the cyanobacterium, inoculated with liquid cultures of SG‐3, and incubated as static cultures. The reduction in dry weights ranged from –0.5% to 90% compared to the untreated controls and appeared to be species specific. For example, dry weight reductions of Oscillatoria deflexoides and O. amoena ranged from 80 to 90% whereas the reduction of O. limosa tended to be lower at 36 to 72%. Although results varied among and within species, they indicate that this bacterium could have potential for use as a biological control for mat‐forming cyanobacteria. Light microscopic observations indicate the bacteria do not penetrate the cyanobacteria cells. Currently, we are studying the possible causes of the observed cell lysis.
98  Phylodiversity of green algae (chlorophyta) from desert microbiotic crusts
Authors: Lewis L. A. , Lewis P. O.
Published: January 2004

Deserts are not thought of as biodiversity hotspots, but desert microbiotic crust communities represent a largely unknown community type rich in diversity of eukaryotic and prokaryotic taxa. These ecologically important communities have received much attention because of their role in nutrient cycling and soil stabilization in deserts, but they defy characterization by the traditional approach to assessing biodiversity by counting species. While genetically diverse, taxa characteristic of desert crusts are difficult to identify to the species level due to convergent evolution toward simple morphologies, phenotypic plasticity, or poor knowledge about particular lineages. Focusing on the green algae, we show that while biodiversity is difficult to measure in these communities, phylodiversity provides a surrogate measure that more accurately portrays the diversity of organisms, and one that is standardized across the variety of life histories, reproductive strategies and morphological variability that creates problems with species‐counting measures. Bayesian phylogenetic inference uses MCMC simulation to generate phylogenies sampled in proportion to their Bayesian posterior probability. The length of a segment in any of these trees corresponds to the amount of change in the lineage, measured as the expected number of substitutions/nucleotide site. Comparisons of segment lengths corresponding to desert vs. other green algal lineages provides a means of addressing questions of relative genetic diversity, or phylodiversity, without complications arising from the difficulty of counting species. Our data illustrate the impact of desert green algae to overall knowledge of the green algal phylogenetic tree.
99  Teaching biological research using brown algae
Authors: Lewis R. J.
Published: January 2004

Mentoring students in investigative research is a key part of actively engaging them in learning biology. While this is best accomplished by involving students in individualized research projects, it is not always feasible to offer such an opportunity to all students. A course in Biological Research that focuses on doing research with a particular “model system” has been an indispensable part of our biology curriculum. Algae provide ideal model systems for this purpose, and kelp gametophytes, including Macrocystis and other genera, have provided excellent results. In the first half of this course, students learn to access information in the published literature, while writing a literature review that relates to a research project that they will propose and design together with a student partner. Simultaneously, they learn useful techniques to grow and manipulate kelp gametophytes. During the second half, they mainly conduct the proposed research. Students present their research proposals and final results to the rest of the class. Most research projects dealt with growth responses or molecular genetics. Growth and survival of gametophytes was determined in response to nutrients or toxicants. Kelp DNA was amplified by PCR in a variety of projects, including later analysis by sequencing or SSCP and RAPDs. Kelp gametophytes proved to be an ideal organism for this course, since growth responses can be measured relatively rapidly, and DNA extraction is relatively simple due to their filamentous morphology.
170  Wetland Diatom Assemblages as Indicators of Flooding Influence and Surrounding Landuse in the Willamette Valley, OR
Authors: Weilhoefer C. L. , Pan Y.
Published: January 2004

The objective of this study was to examine the influences of the adjacent river and surrounding landuse on wetland diatom distributional patterns. Diatoms were identified in surface sediment samples from 35 riverine‐impounded wetlands within the Willamette Valley, OR. A total of 221 species were identified and no single species dominated the assemblage at all sites. Diatom richness was high throughout the area (median 71, range 66–75). The Araphidineae:Centrales index, a measure of periphytic to planktonic species ratio, was lowest at sites within the river's annual floodplain zone. A low A:C index is to be expected at wetlands that receive inputs of river planktonic species through regular flooding by adjacent large rivers. Surrounding landuse can confound the influence of riverine flooding on wetland diatom assemblages by influencing water quality. Relative abundance of the two most common species, Aulacoseira crenulata and Fragilaria capusina related negatively to % agricultural landuse surrounding the wetland. These results indicate that riverine wetland diatom assemblages may be influenced by flooding from adjacent rivers and surrounding landuse and therefore wetland sediment diatoms might serve as useful indicators of both historical environmental changes in nearby large rivers and surrounding watersheds.
171  Light‐Induced Growth of Winter Phytoplankton Collected from the Benthic Boundary Layer in Coastal Oregon Waters
Authors: Wetz M. S. , Wheeler P. A. , Letelier R. M.
Published: January 2004

It has been speculated that overwintering phytoplankton in the benthic boundary layer (BBL) are seed stocks for spring blooms in coastal upwelling systems. Experiments were conducted in Jan/Feb 2003 to test the hypothesis that phytoplankton in the BBL are light limited. Water collected from the BBL at four sites across the northern Oregon shelf was incubated at in situ temperature and nutrient concentrations (∼1 μM phosphate, 10 μM nitrate, 15 μM silicate) and exposed to two different daylengths and four light levels. The daylengths were 9 h (winter) and 12 h (early spring), and the light levels (in μmol photons·m−1 ·s−1) were 0 (Control), 20 (L), 70 (M), and 160 (H). Light‐induced growth was observed in all four incubations. Exponential growth was reached in the 12 H, 12 M, and 9 H treatments after 4 to 6 days, and stationary growth was reached after 5 to 10 days. Maximum in vivo fluoresence was obtained in the 12 H, 12 M, and 9 H treatments, while maximum particulate organic carbon (POC) was obtained in the 12 H treatment. In vivo fluorescence increased in the L light treatments relative to the control, but POC did not. Blooms were terminated by nitrate or silicate depletion. These results demonstrate that growth of winter phytoplankton off Oregon is primarily light‐limited, and that input of light of sufficient intensity and constancy (i.e. water column stabilization) can lead to blooms on time scales typical of upwelling blooms (<1 week).
172  Flexible Elemental Stoichiometry in Trichodesmium IMS101: Implications for Buoyancy‐Mediated Vertical Migration
Authors: White A. E. , Letelier R. M. , Spitz Y. H.
Published: January 2004

The cyanobacterium Trichodesmium is considered the most abundant and active nitrogen fixing plankton genus in tropical and subtropical marine waters. In the northern subtropical gyres of the Pacific and Atlantic Oceans, this organism is notable as a source of new production and as a potential biological shuttle for phosphorus to surface waters. We have conducted recent laboratory experiments revealing the remarkable stoichiometric flexibility exhibited by this diazotroph. These results indicate that Trichodesmium spp. are capable of viable growth with carbon to phosphorus ratios approximately 16 times Redfield stoichiometry. Such P‐sparing is clearly an adaptation to the oligotrophic environments from which these cultures were isolated. Building on this research, additional work was performed to determine the maximal temporal scale of vertical migration and the implicit dark period physiology. An experiment was designed to assess the physiological changes that would occur as cells of varying growth stages migrated below the euphotic zone into more phosphorus replete waters. At different stages of growth sub‐samples of phosphorus replete or phosphorus limited cells were transferred to dark conditions. For each dark bottle, chl‐a, particulate carbon, phosphorus and nitrogen, trichome count and fluorescence parameters were measured daily. Our experimental results indicate that the maximum duration of dark period survival (and hence vertical migration) is approximately three days during which period cells were able to fully recover from light depravation and resume typical growth rates. The knowledge of Trichodesmium bioenergetics gained from this research will serve to further constrain the potential role of Trichodesmium spp. in biogeochemical cycling.
173  Challenges in Preventing, Eradicating, and Controlling Invasive Seaweeds: The Southern California Invasion of Caulerpa Taxifolia as a Model
Authors: Williams S. L.
Published: January 2004

Invasions of marine communities by seaweeds are increasing globally. Vectors for introductions are primarily aquaculture and the aquarium trade. Attention to these vectors has been minimal, and few, if any, regulations exist to prevent seaweed introductions. Challenges in preventing, eradicating, and controlling invasive seaweeds will be discussed using the invasion of Caulerpa taxifolia in southern California as a model.
174  Phylogenetic Relationships Within Centroceras Kuetzing (Ceramiaceae, Rhodophyta)
Authors: Won B. Y. , Cho T. O. , Fredericq S.
Published: January 2004

Centroceras clavulatum (C. Agardh) Montagne (1846) is a widely distributed species worldwide, originally described from Callao, Peru. Populations referred to in the literature as C. clavulatum were investigated on the basis of rbcL sequence analysis and comparative morphology. Four well‐supported clades were identified. RbcL sequence divergence within clades was <0.8, between clades 1.1–8.1%. We conclude that C. clavulatum may encompass at least three additional species that may have been placed under its synonymy. The four well‐supported clades under study are distinct from Centroceras internitens Gallagher & Humm and include, respectively, representative specimens with the following distribution: (1) California, Gulf of California, Korea, Japan, (2) E Florida, Texas, (3) California., and (4) W and E Florida. Studies are underway to assign a correct species name to each of the clades under study.
175  Toward an Optical Biogeography of the Oceans
Authors: Wood A. M.
Published: January 2004

Remote sensing of ocean color has revolutionized our ability to understand the processes leading to the observed distribution of different taxa in marine waters. Many scientists in the remote sensing and optics community are working toward retrieval of species distributions using ocean color measurements to derive the concentration of recognized chemotaxonomic markers. In this talk, I work toward an optical biogeography of the ocean by viewing the optical environment as a selection regime that creates biogeographic boundaries or “optical fences” defining the distribution of taxa with different light harvesting systems and/or different physiologies. Working primarily with data from a wide range of tropical, sub‐tropical, and warm temperate coastal margins, I show that there is a close association between the distribution of different spectral forms of PE‐containing picocyanobacteria and the optical properties of the water masses in which they are found. This pattern also appears to be reflected in the distribution some dinoflagellate taxa, indicating that the optical environment encompasses a range of key niche parameters that, in turn, determine the biogeographic distribution of species.
176  New Discoveries Regarding the Benthic Marine Algal Flora of the Sultanate of Oman
Authors: Wynne M. J.
Published: January 2004

Intensive littoral and sublittoral collecting on the monsoon‐impacted rocky shores of southern Oman, made at the end of the summertime monsoon (Sept. 2000 and Sept. 2001), has produced a remarkably high number of undescribed taxa and new records for this region of the Northern Arabian Sea. Taxa to be discussed in this presentation include: a new species of Centroceras that reaches 60 cm in height, is heavily corticated, has distinctively secund branching, and occurs well into the ‘supralittoral fringe’; a new species of Jolyna, which is often branched, is not as long or thick as the more common J. laminarioides, has ascocysts but lacks hair tufts, and also occurs in the supralittoral; a Turbinaria (T. foliosa) that has the least modified blades known in the genus; a remarkably robust and erect species of Leveillea; and an undescribed Gelidium, which has previously passed under the name of ‘Suhria vittata’. A complicated picture has emerged that shows this flora to have biogeographical affinities with pantropical and subtropical regions, the tropical‐subtropical Indo‐Pacific, South Africa, temperate Europe and the Mediterrranean, Japan, as well as revealing components that are characteristic of the Arabian Sea monsoon season and apparent endemics restricted to Oman. This research (the Algal Biodiversity Project of Oman) has been funded by the British Government's Darwin's Initiative grant for the ‘Survival of Species’ and managed by HTS Development, Ltd., of the U.K.
177  Molecular Systematics of the Green Algal Orders Ulotrichales and Ulvales Based on 18S rDNA Sequences
Authors: Wysor B. , O'Kelly C. J. , Bellows W. K.
Published: January 2004

The traditional use of thallus morphology to define lineages within the Ulvophyceae proved problematic because parallelism and convergence obscured natural relationships. The advent of transmission electron microscopy led to a re‐evaluation of groups on the basis of zoid characters. Within TEM‐defined lineages, the Ulotrichales and Ulvales were considered closely related orders, and molecular evidence has substantiated this hypothesis. In our molecular systematic studies of ulvophyceous green algae, we have broadened taxon sampling among these two orders. We show that the Ulvales and Ulotrichales are indeed monophyletic orders. However, the phylogenetic placement of species in the genera Bolbocoleon, Ctenocladus, Phaeophila, Pseudendoclonium and Acroblaste indicates that one or more additional lineages, placed between Ulvales and Ulotrichales in gene sequence trees, must be recognized. These species may constitute a separate order (Ctenocladales) consisting of multiple families. Our findings will be compared with taxonomic concepts based on morphological criteria.
178  Molecular Systematics of the Ulvellaceae (Ulvales, Ulvophyceae) Inferred from Nuclear and Chloroplast DNA Sequences
Authors: Wysor B. , O'Kelly C. J. , Bellows W. K.
Published: January 2004

The diversity and phylogeny of endophytic, microfilamentous green algae in the family Ulvellaceae (Chlorophyta: Ulvophyceae) are poorly understood. Members of this family have suffered a long history of confusing taxonomy, resulting from phenotypic plasticity and few stable morphological characters. Using DNA sequence data from two molecular markers, the plastid encoded elongation factor TU (tufA) and the nuclear encoded small subunit ribosomal DNA (18S rDNA), we tested taxonomic concepts in Ulvellaceae. Concordance between plastid and nuclear phylogenies revealed the following: 1) Ochlochaete is distinct from Acrochaete and may represent a separate family, 2) Ochlochaete is not monotypic, consisting of at least two genetically distinct species, 3) the tribe Ulvelleae, separated from the Acrochaeteae on the basis of radial (versus linear) germination and bifurcate apical cells, is not supported as one of the members, Pringsheimiella scutata groups with a suite of Acrochaete species and 4) the Ochlochaete clade is the proximal outgroup for the Ulvaceae. These findings will be presented in the light of morphological characters that are currently used to define species and genera in the Ulvellaceae.
179  Conjugation Process of a Freshwater Green Alga, Spirogyra Varians (Zygnematales, Charophyceae Examined by Fitc‐Lectins)
Authors: Yoon M. C. , Kim S. H. , Kim G. H.
Published: January 2004

The conjugation processes of filamentous freshwater green alga Spirogyra varians were examined by the use of FITC‐lectins. Conjugation comprised of five steps: 1) array with adjacent filaments, 2) formation of conjugation protrusion (papilla), 3) fusion of the protrusions, 4) formation of conjugation tube, and 5) formation of zygotes. Three lectins, ConA, RCA and UEA, showed considerable labeling during the progression of conjugation. FITC‐ConA labeled the surfaces of filaments throughout the whole conjugation processes. No labeling of FITC‐RCA was detected on the surface of vegetative filaments. FITC‐RCA labeling was observed at the conjugation protrusions only after the papilla formation. Strong labeling continued until formation of zygotes even in hollow area between the conjugation tube. The labeling decreased gradually over time and disappeared when zygotes were formed. FITC‐UEA showed similar labeling pattern with FITC‐RCA except that the labeling did not disappear even after zygote formation. Inhibition experiments using D‐galactose, L‐fucose and D‐mannose, which are complementary carbohydrates for the above lectins, showed considerable decrease of conjugation (<50% vs. 83% in control). Hamagglutination experiment using crude extract of Spyrogyra varians revealed existence of lectins specific for the above carbohydrates. These results suggested that the lectin‐carbohydrate recognition system might be involved in the conjugation of Spirogyra varians.
180  Relationships Between Water and Sediment Characteristics and Benthic Green Macroalgal Abundance in Yaquina Bay, Oregon: 1999–2002
Authors: Young D. R. , Ozretich R. J. , Specht D. T. , Lamberson J. O. , Caldwell R. S. , Hansen G. I. , Stoffey B.
Published: January 2004

“Green tides” or blooms of ulvoid green algae are frequent in Yaquina Bay estuary on the central Oregon coast, USA. Measurements of their biomass were made from late spring to early winter in 1999 at six intertidal sites in the estuary, and were continued through the winter of 2002 at two sites that showed the greatest accumulation. The dominant blooming species were the Enteromorpha linza complex, Ulva fenestrata, E. flexuosa, and E. intestinalis. Red and brown algal abundance was negligable. Nutrients in the central channel were monitored, along with incident light and water column absorbence, and sediment temperature. The abundance of benthic amphipods was negatively correlated with the concentration of dissolved sulfides in porewater. However, dissolved sulfide levels were not correlated with green macroalgae biomass. Additional correlations were sought between the variables measured in an effort to suggest or negate major cause and effect relationships. This research is relevant to discerning the effects of eutrophication as a stressor on estuarine processes and could contribute toward an understanding of anthropogenic impacts on biological communities in coastal ecosystems.
181  Two Lineages Within Griffithsia (Ceramiaceae, Rhodophyta) Based on Plastid Protein‐Coding psaA, psbA and rbcL Genes
Authors: Yang E. C. , Boo S. M.
Published: January 2004

The ceramiaceous red algal genus Griffithsia C. Agardh includes about 27 species that are distributed along tropical to temperate coasts. Although Griffithsia has been subdivided into four groups based on morphology, there are no attempts on molecular phylogeny of the genus. Sequences of psaA, psbA, and rbcL, protein‐coding genes in plastid, were analyzed for nine samples of seven Griffithsia species, 11 samples of four putative relatives such as Anotrichium Nägeli and Halurus Kützing, and three outgroup taxa. Although sequence divergences for psaA and rbcL were higher than those for psbA, the saturation plots for each of psaA, psbA, and rbcL data showed no evidence of saturation at 1st, 2nd, and 3rd codon position. Partition homogeneity test also indicated that psaA, psbA, and rbcL sequences did not result in significantly incongruent trees. Analyses of separate and concatenated data sets indicated that Griffithsia formed two well‐supported clades: one lineage including C. corallinoides, G. pacifica, and G. tomo‐yamadae, and the other lineage having G. antarctica. G. japonica, G. teges, and G. traversii. Our study indicates that psaA and psbA genes as well as rbcL are suitable tools for phylogenetic investigations of the genus Griffithsia.
182  Experimental Harvests of Five Species of Macroalgae Along the Oregon Coast
Authors: Young J. J. , Herczeg B. A. , Shapiro L.P.
Published: January 2004

Macroalgae are the basis of a major global industry. Their nutritional and chemical values have brought strong economic pressure for commercial harvest permits to the State of Oregon, USA. Historically, Oregon has denied these requests because of a lack of understanding of harvest effects on the resource. Three species of phaeophytes (Laminaria setchellii, Alaria marginata, Fucus gardneri) and two rhodophytes (Mastocarpus papillatus, Mazzaella splendens) were subjected to various treatments to determine their ability to recover from harvest. Three year experiments were designed to compare the effects of harvesting during different seasons, different amounts, and different methods. Permanent transects and plots were placed in three study sites along the Oregon coast. Here we present the results from the first growing season. Only A. marginata was found to regain pre‐harvest biomass within one growing season; all species will be monitored for regrowth and resettlement for the next two growing seasons to provide a basis for the management of the potential economic resource.
183  The Environmental Impacts of Harvesting Beach‐Cast Seaweeds
Authors: Zemke‐White W. L. , Speed S. , McClary D.
Published: January 2004

Until recently the commercial collection of beach‐cast seaweeds in New Zealand was prohibited but the legislation has recently been amended to allow permitting of this activity. This review collates existing information on the role of beach‐cast seaweed in coastal ecosystems to describe the nature and extent of the effects that commercial removals of beach cast seaweed may have on the marine environment. It outlines the amount of beach‐cast seaweed available for harvest in New Zealand and the fate of seaweed when not collected; reviewing current information on the importance of beach‐cast seaweeds and its inhabitants on: feeding and nesting shorebirds, and nutritional contribution of seaweed inhabitants to nearshore coastal ecosystems when seaweed is washed back into the sea It also identifies key research gaps related to any environmental impacts that the removal of beach cast seaweed might have.
184  Expressed Gene Arrays in Three Marine Dinoflagellates with Contrasting Trophic Modes Analyzed Via a Small‐Scale Est Sequencing
Authors: Zhang H. , Lin S.
Published: January 2004

In an attempt to determine the common and unique the genes functioning for different trophic modes in dinoflagellates, cDNA libraries were constructed for Prorocentrum minimum (photoautotrophic), Karlodinium micrum (mixotrophic), and Pfiesteria piscicida (kleptoplastic heterotrophic). Randomly selected 100–350 clones were sequenced for each species. Results revealed a small number of genes transcribed in all three species (basic nuclear proteins, ribosomal proteins). There appeared to be a suite of unique genes in each species. In P. piscicida that was fed Rhodomonas sp., the array of expressed genes differed clearly among different growth conditions. The cDNA library prepared for samples collected 12 h after feeding contained more photosynthetic genes (light harvesting complex proteins) and ribosomal proteins, while growth‐related genes were expressed more abundantly at 24 hours after feeding. At 48 hours when growth rate was decreased dramatically, the most abundant gene transcripts found were those involved in metabolism (mt cob, cox1 and cox3). In addition, several genes (ras, rac, chaperonin) appeared to be identical at amino acid level among the two heterotrophic or mixotrophic dinoflagellates (P. piscicida and K. micrum) and a prey alga (Rhodomonas sp.), although the likelihood of contamination was small. These results suggest that some of the dinoflagellate genes may be originated through horizontal transfer from historical prey species and RT‐PCR measurements indicate that these genes maybe highly expressed in dinoflagellates.
185  Phytate Utilization by Tetrahymena
Authors: Ziemkiewicz H. T. , Johnson M. D. , Smith‐Somerville H. E.
Published: January 2004

Phytate, myo‐inositol hexakisphosphate, is the storage form of phosphate in seeds and grains and a major form of environmental phosphate loading from fertilizer inputs and agricultural runoff. Little is known about the effects of phytate on heterotrophic protozoa. Members of the genus Tetrahymena were chosen as the model organisms for this study because of their wide geographic distribution and adaptability. We found that Tetrahymena can use phytate as their sole phosphate source and that growth is comparable to that for cells grown in media containing orthophosphate. The internal phytate concentration increases dramatically during the logarithmic phase of growth and then decreases during the stationary phase. These internal levels in T. vorax are as much as 10‐fold greater than those for cells grown in phosphate without phytate, suggesting diet as a main source of accumulation. In T. thermophila, the internal phytate level also decreases during stationary phase, but the levels during both logarithmic and stationary phase of growth are similar whether cells are grown in phytate or phosphate. Tetrahymena thermophila possesses several nonspecific acid phosphatases capable of using phytate as a substrate including one associated with the pellicle. We are examining the properties of this phytase.
Are Imports and Exports Cointegrated? An International Comparison
Authors: Irandoust Manuchehr , Ericsson Johan
Published: January 2004

In this paper we use the Johansen and Juselius cointegration technique to examine the long‐run convergence between imports and exports for a number of industrialized countries. The results indicate that there exists a long‐run steady‐state relationship between imports and exports for most countries in the sample. The policy implications of our findings are that the countries are not in violation of their international budget constraints and, more importantly, there is no productivity gap between the domestic economy and the rest of the world, implying a lack of permanent technological shocks to the domestic economy.
The Labour Theory of Value as Foundation for Empirical Investigations
Authors: Mohun Simon
Published: January 2004

This paper outlines some recent approaches to the construction of an accounting structure which relates observable prices to Marxian labour values. The first is that proposed (independently of each other) by Duménil and Foley (DF); the second in some sense is a generalization which focuses on gross value produced rather than net value added; and a third imposes some temporal structure upon the second approach. The second two approaches are based on different definitions of labour value from that in the DF approach, and in the paper it is argued that the DF approach is both more theoretically coherent and more practically useful.
Decomposition dynamics in mixed‐species leaf litter
Authors: Gartner Tracy B. , Cardon Zoe G.
Published: January 2004

Literature on plant leaf litter decomposition is substantial, but only in recent years have potential interactions among leaves of different species during decomposition been examined. We review emerging research on patterns of mass loss, changes in nutrient concentration, and decomposer abundance and activity when leaves of different species are decaying in mixtures. Approximately 30 papers have been published that directly examine decomposition in leaf mixtures as well as in all component species decaying alone. From these litter‐mix experiments, it is clear that decomposition patterns are not always predictable from single‐species dynamics. (Characteristics of decomposition in litter‐mixes that deviate from responses predicted from decomposition of single‐species litters alone are designated "non‐additive"; "additive" responses in mixes are predictable from component species decaying alone.) Non‐additive patterns of mass loss were observed in 67% of tested mixtures; mass loss is often (though not always) increased when litters of different species are mixed. Observed mass loss in some mixtures is as much as 65% more extensive than expected from decomposition of single‐species litter, but more often mass loss in mixtures exceeds expected decay by 20% or less. Nutrient transfer among leaves of different species is striking, with 76% of the mixtures showing non‐additive dynamics of nutrient concentrations. Non‐additive patterns in the abundance and activity of decomposers were observed in 55% and 65% of leaf mixes, respectively. We discuss some methodological details that likely contribute to conflicting results among mixed‐litter studies to date. Enough information is available to begin formulating mechanistic hypotheses to explain patterns in litter‐mix experiments. Emerging patterns in the mixed‐litter decomposition literature have implications for relationships between biodiversity and ecosystem function (in this case, the function being decomposition), and for potential mechanisms through which invasive plant species could alter carbon and nutrient dynamics in ecosystems.
Phenology of neotropical pepper plants (Piperaceae) and their association with their main dispersers, two short‐tailed fruit bats,Carollia perspicillataandC. castanea(Phyllostomidae)
Authors: Thies Wibke , Kalko Elisabeth K. V.
Published: January 2004

To relate differences in phenological strategies of a group of closely related plants to biotic (pollinators, dispersers) and abiotic (water, light) factors, we studied leafing, flowering, and fruiting phenology of 12 species ofPiper(Piperaceae) in a neotropical lowland forest in Panama for 28 months. We asked howPipermay partition time and vertebrate frugivores to minimize possible competition for dispersal agents. Based on habitat preferences and physiological characteristics we discriminate between forestPiperspecies (eight species) and gapPiperspecies (four species). ForestPiperspecies flowered synchronously mostly at the end of the dry season. GapPiperspecies had broader or multiple flowering peaks distributed throughout the year with a trend towards the wet season. Both groups ofPiperspecies showed continuous fruit production. Fruiting peaks of forestPiperspecies were short and staggered. GapPiperspecies had extended fruiting seasons with multiple or broad peaks. Both groups ofPiperspecies also differed in their time of ripening and disperser spectrum. ForestPiperspecies ripened in late afternoon and had a narrow spectrum consisting mainly of two species of frugivorous bats:Carollia perspicillataandC. castanea (Phyllostomidae). Fruits of gapPiperspecies, in contrast, ripened early in the morning and were eaten by a broader range of diurnal and nocturnal visitors, including bats, birds, and ants. We conclude that the differences in flowering phenology of forest and gapPiperspecies are primarily caused by abiotic factors, particularly the availability of water and light, whereas differences in fruiting patterns are mostly influenced by biotic factors. The staggered fruiting pattern of forestPiperspecies may reflect competition for a limited spectrum of dispersers. The long and overlapping fruiting periods of gapPiperspecies are associated with a larger spectrum of dispersers and may be a strategy to overcome the difficulty of seed dispersal into spatially unpredictable germination sites with suitable light conditions.
Influenza Virus: Immunity and Vaccination Strategies. Comparison of the Immune Response to Inactivated and Live, Attenuated Influenza Vaccines
Authors: Cox R. J. , Brokstad K. A. , Ogra P.
Published: January 2004

Influenza virus is a globally important respiratory pathogen which causes a high degree of morbidity and mortality annually. The virus is continuously undergoing antigenic change and thus bypasses the host's acquired immunity to influenza. Despite the improvement in antiviral therapy during the last decade, vaccination is still the most effective method of prophylaxis. Vaccination induces a good degree of protection (60–90% efficacy) and is well tolerated by the recipient. For those at risk of complications from influenza, annual vaccination is recommended due to the antigenic changes in circulating strains. However, there is still room for improvement in vaccine efficacy, long‐lasting effect, ease of administration and compliance rates. The mucosal tissues of the respiratory tract are the main portal entry of influenza, and the mucosal immune system provides the first line of defence against infection. Secretory immunoglobulin A (SIgA) and IgM are the major neutralizing antibodies directed against mucosal pathogens. These antibodies work to prevent pathogen entry and can function intracellularly to inhibit replication of virus. This review describes influenza virus infection, epidemiology, clinical presentation and immune system response, particularly as it pertains to mucosal immunity and vaccine use. Specifically, this review provides an update of the current status on influenza vaccination and concentrates on the two main types of influenza vaccines currently in use, namely the cold‐adapted vaccine (CAV) given intranasally/orally, and the inactivated vaccine (IV) delivered subcutanously or intramuscularly. The commercially available trivalent IV (TIV) elicits good serum antibody responses but induces poorly mucosal IgA antibody and cell‐mediated immunity. In contrast, the CAV may elicit a long‐lasting, broader immune (humoral and cellular) response, which more closely resembles natural immunity. The immune response induced by these two vaccines will be compared in this review.
Harmonic Imaging Improves Sensitivity at the Expense of Specificity in the Detection of Patent Foramen Ovale
Authors: Madala Durga , Zaroff Jonathan G. , Hourigan Lisa , Foster Elyse
Published: January 2004

Contrast echocardiography using agitated saline is widely employed to detect right to left shunt in patients with suspected patent foramen ovale (PFO). The sensitivity of fundamental transthoracic echocardiography (FTTE) is often limited by poor far‐field resolution. The purpose of this study was to evaluate the test characteristics of harmonic imaging during transthoracic echocardiography (HTTE) for the detection of PFO. Methods: Sixty‐four patients referred for transesophageal echo (TEE) for clinical indications underwent FTTE and HTTE during saline contrast injections. Results: TEE identified nine PFOs. For FTTE, the sensitivity was 78% and the specificity was 100%. For HTTE, the sensitivity was 100% and the specificity was 82%. All ten false positives with HTTE occurred after five cardiac cycles, suggesting transpulmonary transit of the bubbles. Conclusion: In the detection of PFO, HTTE improves sensitivity at the expense of specificity, particularly if the timing of contrast appearance in the left heart is ignored. (ECHOCARDIOGRAPHY, Volume 21, January 2004)
Relative Duration of Transmitted Mitral A Wave as a Measure of Left Ventricular End‐Diastolic Pressure and Stiffness
Authors: Pai Ramdas G. , Varadarajan Padmini
Published: January 2004

Background and objectives: The mitral A wave is transmitted to the left ventricular (LV) outflow tract where it is registered as Ar wave. We have related its transit time to the LV late diastolic stiffness. We also observed incidentally that the duration of the transmitted Ar wave exhibited marked variability and hence investigated its hemodynamic correlates. Methods and results: Mitral A wave and the Ar wave in the LV outflow tract were recorded using pulsed wave Doppler technique simultaneous with high fidelity LV pressure recordings in 20 patients undergoing cardiac catheterization. A high‐speed contrast left ventriculogram was obtained as well. The duration of both these wave forms were measured and A wave duration minus the Ar wave duration was measured. The A minus Ar wave duration (range 0–95 ms) correlated with LV end‐diastolic pressure (r = 0.54, P = 0.014, range 4–32 mmHg), LV late diastolic stiffness (r = 0.62, P = 0.004, range 0.1–1.6 mmHg/ml) and the amount of LV pressure rise with atrial contraction (r = 0.67, P = 0.001, range 2–13 mmHg). Conclusion: A minus Ar wave duration is an easily obtainable Doppler parameter that is related to LV late diastolic filling pressures and stiffness and gives insights into aspects of LV diastolic function. (ECHOCARDIOGRAPHY, Volume 21, January 2004)
2  TESTING LIMA GRAFT PERMEABILITY BY TRANSTHORACIC ECHO‐DOPPLER.
Authors: Madariaga I. , Ansa I. , Ancin R. , De La Fuente A. , Sánchez R. , Fernández J.L. , Moriones I.
Published: January 2004

Purpose: Postoperative measurement of graft permeability by angiography is invasive. The aim of this study is to evaluate the utility of transthoracic echo‐Doppler (TTE) in measuring LIMA graft permeability.

Methods: We studied 89 consecutive patients (average age 65 years, range 37–79 years) who were revascularized with a LIMA. Graft permeability was evaluated by both color‐ and pulsed‐Doppler TTE. We measured the following parameters: systolic velocity peak (SVP), diastolic velocity peak (DVP), average velocity, pulsatility index (PI), resistivity index (RI). Of the 89 patients, 60 also underwent angiography. We considered stenosis to be severe if greater than 70% as indicated by angiography.

Results: We were able to obtain TTE data for 85 patients (95.5%) and of these 57 had angiography as well. Doppler registers were biphasic, with both systolic and diastolic components. In patients with grafts functioning normally, registers were predominantly diastolic. When the graft was dysfunctional registers were predominantly systolic (similar to the register of the mammary artery in its anatomic position). Patients with dysfunctional grafts had higher SVP (p < 0.01), higher DVP (p < 0.05), and higher PI (p < 0.001). The sensitivity and specificity of TTE in the detection of severe graft dysfunction were 86% and 100%, respectively. The positive prediction value was 100%.

Conclusions: TTE has high sensitivity, specificity, and predictive value in determination of LIMA graft permeability. Being noninvasive, TTE is ideal for the follow‐up of patients with LIMA grafts.
Disruption of self‐organized actions in monkeys with progressive MPTP‐induced parkinsonism: II. Effects of reward preference
Authors: Pessiglione Mathias , Guehl Dominique , Jan Caroline , François Chantal , Hirsch Etienne C. , Féger Jean , Tremblay Léon
Published: January 2004

The motor and cognitive symptoms of Parkinson's disease (PD) are well documented, but little is known about the functionality of motivational processes mediated by the limbic circuits of basal ganglia. The aim of this study was to test the ability of motivational processes to direct and to urge behaviour, in four vervet monkeys (Cercopithecus aethiops) progressively intoxicated with systemic 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) injections (0.3–0.4 mg/kg every 4–7 days). In the food preference task, the monkeys had to retrieve two types of directly visible food, simultaneously available in the wells of a reward board. At all stages of MPTP‐induced parkinsonism, the monkeys continued to take their favourite food first. In the symbol discrimination task, the wells were covered with sliding plaques cued by symbols indicating the absence or presence of a reward, and the different types of food were blocked in separate sessions. Monkeys with mild or moderate parkinsonism made fewer attempts and took longer to retrieve non‐preferred compared with preferred rewards. These results indicate that motivational processes are still able to direct (food preference task) and to urge (symbol discrimination task) behaviour in MPTP‐lesioned monkeys. Such a functional preservation may be related to the relatively spared dopaminergic innervation of the limbic circuits that we found in our monkeys, in agreement with the literature on humans. Furthermore, the frequency of executive disorders (such as hesitations and freezing) appeared to be much lower with the preferred rewards. Thus, the preserved motivational processes may help to overcome executive dysfunction in the early stages of human PD.
Selective deficits in appetitive conditioning as a consequence of ethanol withdrawal
Authors: Ripley T. L. , Borlikova G. , Lyons S. , Stephens D. N.
Published: January 2004

The acquisition of a conditioned response to a cue associated with a fearful event has been shown to be impaired in animals that had been repeatedly withdrawn from ethanol, but not in animals with the same chronic ethanol treatment but only a single withdrawal episode [D. N. Stephens et al. (2001) Eur. J. Neurosci., 14, 2023–2031]. Lesion studies have shown that the amygdala plays a vital role in this type of conditioning process. Here we investigate aspects of conditioning for appetitive reinforcers in operant tasks, also shown to rely on amygdala processing, in rats following repeated withdrawal from ethanol. Rats were chronically treated with either an ethanol‐containing liquid diet for 24 days continuously (single withdrawal) or interspersed with 2 × 3‐day withdrawal periods (repeated withdrawal), or with a control diet (control). Two weeks after the final withdrawal, operant training began. In tasks that are impaired by lesions of the basolateral amygdala, conditioned reinforcement and reinforcer devaluation, there was no effect of chronic ethanol treatment or withdrawal on acquisition or performance. However, in a task that is dependent upon functioning of the central nucleus of the amygdala, Pavlovian‐to‐instrumental transfer, the single and repeated withdrawal groups were significantly impaired. Therefore, chronic ethanol treatment and withdrawal resulted in deficits in behavioural tasks that are sensitive to central but not to basolateral amygdala lesions, and may reflect different sensitivities of these areas to ethanol.