bluuebunny/crossref_metadata_2025 huggingface dataset:
BIOMASS AND DYNAMICS OF GROWTH OF ULVA SPECIES IN PALMONES RIVER ESTUARY1
Authors: Hernández Ignacio , Peralta Gloria , Pérez‐Lloréns J. Lucas , Vergara Juan J. , Niell F. Xavier
Published: October 2004

During the last decade, the Palmones River estuary has undergone severe eutrophication followed by a green tide episode; two species of Ulva, rotundata Blid. and Ulva curvata (Kütz.) De Toni, were the main macroalgae responsible for this bloom. From November 1993 to December 1994, we followed the biomass, the growth dynamics, and tissue elemental composition (C:N:P)of Ulva species, as well as some physicochemical variables in the estuary. Maximum biomass (up to 375 g dry wt·m−2 in some spots, corresponding to a thallus area index of nearly 17 m2Ulva·m−2 sediment) were observed in June and December. However, the biomass varied among the sampling stations. Water nitrate, ammonia, and phosphate showed high concentrations throughout the year, with extremely high transient pulses, sustaining the high growth rates observed. Growth rates were estimated directly in the field. The rates were generally higher in Ulva discs maintained in net cages than those estimated by changes in biomass standing stock between two consecutive samplings. The difference between both estimates was used to quantify the importance of the processes causing loss of biomass, which were attributable to grazing, exported biomass, and thallus decomposition under anaerobic conditions resulting from extreme self‐shading. Maximum chlorophyll content was found in winter, whereas the minimum was in spring. Atomic N:P ratios were generally higher in the algae than in the water. However, the absolute concentrations of tissue N and P were always higher than the critical levels for maximum growth, which suggests that growth was not limited by inorganic N or P availability. The results suggested that the increase in nutrient loading in the river may have triggered the massive development of green algae and that light limitation and temperature stress in summer seem to be the main factors controlling the abundance of Ulva in the estuary. In addition to light availability and thermal stress, the different loss processes may have a decisive role in the dynamics of Ulva biomass.
THE ROLE OF NITROGEN NUTRITION IN HIGH‐TEMPERATURE TOLERANCE OF THE KELP, LAMINARIA SACCHARINA (CHROMOPHYTA)1
Authors: Gerard Valrie A.
Published: October 2004

Mechanisms of high‐temperature tolerance in the kelp Laminaria saccharina (L.) Lamour. were examined by comparing a heat‐tolerant ecotype from Long Island Sound (LIS), New York, and a population from the Atlantic (ATL) coast of Maine. Greater heat tolerance was not attributable to greater thermal stability of the photosynthetic apparatus: LIS and ATL plants exhibited similar short‐term effects of high temperature on photosynthetic capacity (Pmax) and quantum yield (estimated as the ratio of variable to maximum chlorophyll fluorescence, Fv/Fm. As LIS plants had consistently higher N and protein content than ATL plants, the interaction between nitrogen nutrition and high‐temperature tolerance was examined. When grown under high N supply and optimal temperature (12° C), LIS plants had a higher density of photosystem II reaction centers (RCII), higher activity of two Calvin cycle enzymes (ribulose bisphosphate carboxylase oxygenase [RUBISCO] and NADP‐dependent glyceraldehyde‐3‐phosphate dehydrogenase [G3PDH]), and higher Pmax and Fv/Fm than ATL plants. Individual ATL plants, furthermore, exhibited close correlations of RCII density and enzyme activity with N and/or protein content. Variation in RCII density and enzyme activity, in turn, largely accounted for plant‐to‐plant differences in Pmax and Fv/Fm. Relationships among these parameters were generally weak or lacking among individual LIS plants grown under optimal conditions, apparently because luxury N consumption resulted in excess reserves of photosynthetic apparatus components. Exposure of N‐replete LIS and ATL plants to a superoptimal temperature (22° C) for 4 days caused an increase in the minimum turnover time of the photosynthetic apparatus (tau) and a decrease in Pmax, but had no consistent effect on Fv/Fm RCII density, PSU size (chlorophyll a/RCII), or enzyme activities. When plants were subjected to concurrent N limitation and heat stress, however, LIS and ATL populations exhibited quite different responses. All photosynthetic parameters of N‐limited ATL plants declined sharply in response to high temperature, resulting in a negative rate of daily net C fixation. In contrast, LIS plants showed a reduction in PSU size, but maintained other parameters, including daily C fixation, at levels similar to those of N‐limited plants at optimal temperature. Overall, the ability of LIS plants to accumulate and maintain high N reserves appears to be critical for heat tolerance and, therefore, for survival during summer periods of simultaneous low N supply and superoptimal temperature. ATL plants, which also experience low summer N supply but not superoptimal temperatures, do not accumulate large reserves of nitrogenous components and are unable to tolerate the combined stress. Because low N supply often co‐occurs with high temperatures in temperate marine systems, large‐scale declines in algal productivity, such as during El Niño events, are probably due to the interactive effect of N limitation and heat stress.
ABUNDANT PLASMID‐LIKE DNA IN VARIOUS MEMBERS OF THE ORDERS SIPHONOCLADALES AND CLADOPHORALES (CHLOROPHYTA)1
Authors: La Claire John W. , Zuccarello Giuseppe C. , Tong Shun
Published: October 2004

In all seven genera belonging to the order Siphonocladales and in two genera of the Cladophorales (Chlorophyta) that were examined, extracts of total DNA contained abundant low molecular weight (LMW) molecules. This DNA typically ranged in size from 1.5 to 3.0 kb among the different genera studied. The complexity of the populations of molecules found in different genera also varied with regard to sizes and numbers of bands evident in electrophoresis gels. Our data suggest that the LMW DNA is ubiquitous among these algae since it occurred in each of our six isolates of Ernodesmis verticillata (Kützing) Børgesen collected in both the Caribbean and the Gulf of California. The LMW DNA from Ernodesmis and Ventricaria ventricosa (J. Agardh) Olsen et J. West was denser than high molecular weight (HMW) DNA in CsCl/bisbenzimide gradients. Ultrastructurally, the LMW DNA molecules were linear, averaging 0.65 μm (Ernodesmis) and 1.0 μm (Ventricaria) in length. Approximately 2%–5% of the former possessed an apparent loop or lariat at one end, as visualized in the electron microscope after rotary shadowing. The LMW DNA molecules appeared to be predominantly double‐stranded DNA based upon staining with acridine orange. The 2.2‐kb DNA from Ernodesmis has features typical of plasmids in that it rapidly reannealed after heat denaturation, and it was selectively enriched in an alkaline‐lysis extraction procedure. In denaturing gels, this DNA migrated at >4.0 kb, indicating that the molecules may actually be single‐stranded DNA species with intramolecular base pairing, each containing a long inverted repeat folded back on itself in a hairpin conformation in the native state. Digestion with mung bean nuclease revealed that additional single‐stranded regions may occur in many of the LMW molecules, in addition to the hairpin loop. Although the endonuclease DNase I rapidly digested the LMW DNA, neither exonuclease III nor lambda exonuclease digested it. This suggests that the ends of these DNA molecules are protected. Collectively, the data indicate that members of the Siphonocladales and Cladophorales contain linear plasmid‐like DNA molecules that appear to have a novel combination of features.
THREE NEW BENTHIC SPECIES OF PROROCENTRUM (DINOPHYCEAE) FROM BELIZE: P. NORRISIANUM SP. NOV., P. TROPICALIS SP. NOV., and P. RETICULATUM SP. NOV.1
Authors: Faust Maria A.
Published: October 2004

Three new benthic, photosynthetic dinoflagellate species, Prorocentrum norrisianum, Prorocentrum tropicalis, and Prorocentrum reticulatum, from floating detritus and coral rubble of Central America are described from scanning electron micrographs. Species were identified based on shape, size, surface micromorphology, thecal plate ornamentation, and architecture of the periflagellar area and intercalary band.

Cells of P. norrisianum are ovate with a cell size of 20–25 μm long and 13–16 μm wide. The theca is delicate, its surface smooth, pores species specific with 95 to 105 pores per valve. Pores are round with a diameter of about 0.1 μm. The periflagellar area is V‐shaped, located on the right valve in a shallow depression. It has no ornamentation. The flagellar and auxiliary pores are unequal in size. The intercalary band is smooth.

Prorocentrum tropicalis cells are ovoid, 50–55 μm long and 40–45 μm wide in valve view with maximum width behind the middle region, narrow at the anterior end. The periflagellar area, situated in the right valve, is a V‐shaped wide triangle with a deeply indented depression; the left valve exhibits a flat ridge. The periflagellar area is unornamented, and the flagellar and auxiliary pores are unequal in size. The valve surface is rugose with evenly distributed valve poroids. Each poroid appears to have a small dome in the center. The intercalary band is rimlike around the cell margin, granulated, and horizontally striated.

Prorocentrum reticulatum cells are oblong in valve view; cells are 55–60 μm long and 40–45 μm wide. Thecal surface is reticulated; it is composed of a labyrinth of ridges with alternating depressions that vary in size and shape. Each depression has a narrow, oblong‐kidney‐shaped opening about 0.6 μm long. The periflagellar area is a deep, V‐shaped triangle. The right valve of P. reticulatum is excavated, and contains a large flagellar pore and a smaller auxiliary pore surrounded by a narrow apical collar. The left valve margin exhibits a curved flat ridge. The intercalary band is smooth.
PHYLOGENETIC ANALYSIS OF EUDORINA SPECIES (VOLVOCACEAE, CHLOROPHYTA) BASED ON rbcL GENE SEQUENCES1
Authors: Nozaki Hisayoshi , Ito Motomi , Uchida Hidenobu , Watanabe Makoto M. , Kuroiwa Tsuneyoshi
Published: October 2004

Species and varieties in the genus Eudorina Ehrenberg (Volvocaceae, Chlorophyta) were evaluated on the basis of phylogenetic analyses of the large subunit ofribulose‐1,5‐bis‐phosphate carboxylase/oxygenase (rbcL) gene sequences from 14 strains of four Eudorina species, as well as from nine species of Pleodorina and Volvox. The sequence data suggested that 10 of the 14 Eudorina strains form three separate and robust monophyletic groups within the nonmonophyletic genus Eudorina. The first group comprises all three strains of E. unicocca G. M. Smith; the second group consists of one of the E. elegans Ehrenberg var. elegans strains, the E. cylindrica Korshikov strain, and both E. illinoisensis (Kofoid) Pascher strains; and the third group consists of two monoecious varieties of E. elegans [two strains of E. elegans var. synoica Goldstein and one strain of E. elegans var. carteri (G. M. Smith) Goldstein]. In addition, E. illinoisensis represents a poly‐ or paraphyletic species within the second group. The remaining four strains, all of which are assigned to E. elegans var. elegans, are nonmonophyletic. Although their position in the phylogenetic trees is more or less ambiguous, they are ancestral to other taxa in the large anisogamous/oogamous monophyletic group including Eudorina, Pleodorina, and Volvox (except for sect. Volvox). Thus, the four Eudorina groups resolved in the present molecular phylogeny do not correspond with the species concepts of Eudorina based on vegetative morphology, but they do reflect the results of the previous intercrossing experiments and modes of monoecious and dioecious sexual reproduction.
THE NATURAL LIFE CYCLE IN WILD POPULATIONS OFDIATOMA MONILIFORMIS(BACILLARIOPHYCEAE) AND ITS DISRUPTION IN AN ABERRANT ENVIRONMENT1
Authors: Potapova Marina , Snoeijs Pauli
Published: October 2004

We studied how size variation in populations ofDiatoma moniliformisKütz. was influenced by environmental effects on the diatom life cycle. One of the two populations sampled monthly in the northern Baltic Sea grew under natural conditions; the other population was in a cooling water discharge channel of a nuclear power plant, where the temperature and flow rate of the water were artificially higher. The life cycle was synchronous at the natural site, with sexual reproduction occurring in the winter; most of the initial cells were found in March‐April. After this, a reduction in cell size occurred, and the vegetative life cycle consisted of two parts. During the first part, cell volume decreased, whereas the surface area to volume ratio increased, and during the second part of the cycle, both of these parameters decreased. No direct evidence was found for the existence of a supra‐annual life cycle inD. moniliformis,as convincing modes fm large cells were lacking in the size‐frequency distributions. It was concluded from extrapolations of the data that the natural life cycle ofD. moniliformisprobably lasts 2 or 3 years. The changes in cell proportions during the life cycle fit well with annual growth cycles ofD. moniliformisat the natural site (i.e. the cells had high surface area to volume ratios during the period of optimal growth in late spring [May‐June]). At the site affected by cooling water discharge, the synchronization of the natural life cycle was disrupted, but some seasonal size variation did occur. Under natural conditions, auxosporulation is probably triggered by a combination of small cell size, low water temperature (0–3° C), and rapidly increasing light intensity or daylength in late winter to early spring. When these conditions were not met (e.g. at the heated site, the required low temperature was absent), auxosporulation did not occur simultaneously. This paper also presents scanning electron photomicrographs showing the typical shape and fine structure of the initial cell ofD. moniliformis.These cells are semispherical in cross section, possess a pronounced curvature along the longitudinal axis, and are bent in the perualvar plane.
FINE STRUCTURE OF THE MALE AND FEMALE GAMETES OFATRACTOMORPHA PORCATA(SPHAEROPLEACFAE, CHLOROPHYTA) WITH EMPHASIS ON THE DEVELOPMENT AND ABSOLUTE CONFIGURATION OF THE FLAGELLAR APPARATUS1
Authors: Cáceres Eduardo J. , Hoffman Larry R. , Leonardi Patricia I.
Published: October 2004

Gametogenesis in Atractomorpha porcata Hoffman was initiated b the synchronous mitotic division of nuclei within a multinucleate gametangium. Uninucleate gametes were subsequently produced following two series of cytokinetic divisions. The first series involved the formation of phycoplast microtubules (phycoplastic cytokinesis), whereas the second series did not (nonphycoplastic cytokinesis). Centrioles were connected by a rudimentary striated distal fiber by the time they migrated to the planes of division preceding the first series of cytokinetic division. These first divisions produced binucleate gametocytes. A well‐developed flagellar apparatus lay near the cell surface in close proximity to each nucleus of the gametocyte prior to the second series of cytokinetic divisions that produced the uninucleate gametes. As seen in apical view, the paired basal bodies were directly opposed, with no lateral displacement of their longitudinal axes. In lateral view, the paired basal bodies diverged from one another at an angle of 130–180° (female) or 170–180° (male) and were connected by an arched, distal striated fiber about 670–750 nm long and 600 nm at its widest part. Four electron‐opaque, pyramid‐shaped lateral bodies flanked the basal bodies in close contact with their undersurfaces. The flagellar roots demonstrated a cruciate arrangement, with s=6–9 over 1 (female gametes) or 7–10 over 1 (male gametes) microtubules and d= 2 microtubules. In male gametes, one of the multistranded roots was located close to the eyespot, and a second system of cytoskeletal microtubules was detected internally. Based on gamete ultrastructure, Atractomorpha porcata appears to be the most undifferentiated member of the genus.
UPTAKE, EFFLUX, AND PHOTOSYNTHETIC UTILIZATION OF INORGANIC CARBON BY THE MARINE EUSTIGMATOPHYTE NANNOCHLOROPSIS SP.1
Authors: Sukenik Assaf , Tchernov Dan , Kaplan Aaron , Huertas Emma , Lubian Luis M. , Livne Alexander
Published: October 2004

Uptake, efflux and utilization of inorganic carbon were investigated in the marine eustigmatophyte Nannochloropsis sp. grown under an air level of CO2. Maximal photosynthetic rate was hardly affected by raising the pH porn 5.0 to 9.0. The apparent photosynthetic affinity for dissolved inorganic carbon (DIC) was 35 μM DIC between pH 6.5 to 9.0, but increased approximately threefold at pH 5.0 suggesting that HCO3‐ was the main DIC species used from the medium. No external carbonic anhydrase (CA) activity could be detected by the pH drift method. However, application of ethoxyzolamide (an inhibitor of CA) resulted an a significant inhibition of photosynthetic O2 evolution and carbon utilization, suggesting involvement of internal CA or CA‐like activity in DIC utilization. Under high light conditions, the rate of HCO3− uptake and its internal conversion to CO2 apparently exceeded the rate of carbon fixation, resulting in a large leak of CO2 from the cells to the external medium. When the cells were exposed to low DIC concentrations, the ratio of internal to external DIC concentration was about eight. On the other hand, in the presence of 2 mM DIC, conditions prevailing in the marine environment, the internal concentration of DIC was only 50% higher than the external one.
VARIATION IN THE OCCURRENCE OF EXTERNAL CARBONIC ANHYDRASE AMONG STRAINS OF THE MARINE DIATOM PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1
Authors: John‐McKay Meryl E. , Colman Brian
Published: October 2004

Eleven different strains of Phaeodactylum tricornutum Bohlin were obtained from three culture collections and were examined for the presence of external and internal carbonic anhydrase (CA). Cells of all strains, grown in standing culture at alkaline pH and low, dissolved inorganic carbon had internal CA, but only eight were found to have external CA. External CA activity was reduced when cultures were bubbled with air and was completely repressed when they were grown on 5% CO2. Expression of external CA activity appears to be regulated by CO2 concentration in the growth medium, but within one species, there appears to be a variation in occurrence of external CA and consequently in the mode of inorganic carbon acquisition.
KINETICS OF CELL DEATH IN THE CYANOBACTERIUM ANABAENA FLOS‐AQUAE AND THE PRODUCTION OF DISSOLVED ORGANIC CARBON1
Authors: Lee Dae‐Young , Rhee G‐Yull
Published: October 2004

Kinetics of cell death and the production of dissolved organic carbon (DOC) were investigated in Anabaena flos‐aquae (Lyngb.) Bréb grown on three different N sources (N2nitrate, and ammonium) in a phosphorus (P)‐limited chemostat. The fraction of live cells in the total population increased as growth rate increased with decreasing P limitation. Cell death was less in nitrate and ammonium media than in N2. The specific death rate (γ), when calculated as the slope ofv−1x vs. D−1, where vxand D are live cell fraction (or cell viability) and dilution rate, respectively, was 0. 0082 day−1 in N2and 0.0042 day−1 in nitrate. The slope of the plot in ammonium culture was not significant; however, the value of the live cell fraction was within the range for the NO−3culture. The fraction of live vegetative cells in N2 culture was constant at all growth rates and the increase in the overall live cell fraction with growth rate was due entirely to an increase in live heterocysts. Live heterocysts comprised 3.5% of the total cells at a growth rate of 0.25 day−1 and increased to 6.3% at 0.75 day−1 with the ratio of live heterocysts to live vegetative cells linearly increasing with growth rate. The fraction of live vegetative cells was invariant in nitrate cultures us in N2cultures. The live heterocysts fraction also increased with growth rate in nitrate cultures, along with the live heterocysts : live vegetative cells ratio, but the level was lower than in N2cultures. DOC released from dead cells increased inversely with growth rate in N2from 36.4% of the total DOC at a growth rate of 0.75 day−1 to 54.15% at 0.25 day−1. The contribution of cell death to the total DOC production in nitrate and ammonium media was significantly less than that under N2DOC from dead cells consisted mainly of high‐molecular‐weight compounds, whereas DOC excreted from live cells was largely of low molecular weight.
A NEW METHOD FOR ESTIMATING EXTERNAL, CARBONIC ANHYDRASE ACTMTY IN MACROALGAE1,2
Authors: Mercado Jesús M. , Figueroa F. L. , Xauier Niell F. , Axelsson Lennart
Published: October 2004

The effects of external carbonic anhydrase (CA, E.C. 4.2.1.1) on HCO−3and CO2use under disequilibnum conditions were examined in 14 species of macroalgae. CO2 was added to the algae in synthetic seawater free from inorganic carbon and buffered to pH 8.7. This resulted in a transient O2 evolution, which was similar for most of the species tested: an initial rapid increase in the rate was followed by a gradual decrease, approaching a steady state within 10 min. The initial high rate of O2evolution was attributed to diffusive entry of CO2into the cells and the steady state to use of HCO−3. An enhancement of CO2diffusive entry was obtained with acetazolamide, an inhibitor of external CA activity. Using this enhancement, a variable was developed to quantify the degree to which CO2entry into the cell was prevented by the external CA. This variable, CA (%), was used as a measure of the external CA activity of the alga. Comparative measurements of the external CA activity using a potentiomtric method revealed that the new method was able to detect low levels of external CA activity, where the potentiometric method failed. These two different methods could be used together to increase the reliability of the measurements. The new method was useful for red and brown macroalgae and for those green macroalgae that lacked direct HCO3uptake. Thus prominent external CA activity was found for Valonia utricularis (green), Halopteris scoparia (brown), and Osmunda pinnatifida (red), where the potentiometric method failed, or nearly failed, to indicate any external CA activity. Direct uptake of HCO−3interfered with the new method and the degree of this interference was dependent on the magnitude of the uptake.
INTER‐ AND INTRASPECIFIC GENETIC VARIATION IN TWELVE PRYMAESIUM (HAPTOPHYCEAE) CLONES1
Authors: Larsen Aud , Medlin Linda K.
Published: October 2004

The haptophytes Prymnesium parvum Carter and Prymnesium patelliferum Green, Hibberd, and Pienaar are two closely related species, which can only be distinguished by minor differences in the morphology of their organic body scales. The two Prymnesium species are reported to coexist at several locations, including the Sands‐fjord system in southwestern Norway. Comparisons of physiology and toxicity within the two species have failed to reveal differences that can add to the small morphological distinctions used to separate them. To investigate the genetic relationship between the two species, we compared the sequence of the first internal transcribed spacer region (ITS1)and length variation in one intron separating calmodulin genes for four P. parvum strains and eight P. patelliferum strains. Both the ITS1 sequence and the banding patterns obtained by PCR amplification of one intron in the calmodulin genes indicated that the Prymnesium isolates are related by their geographic origin instead of 4 their species affiliation. The results indicate that P. parvum and P. patelliferum are so closely related that they could be considered one species. Alternatively, we discuss the possibility that the two species might be joined in a heteromorphic haploid‐diploid life cycle, as is now widely reported for other haptophycean algae.
UNUSUAL DIHYDROXYSTEROLS AS CHEMOTAXONOMIC MARKERS FOR MICROALGAE FROM THE ORDER PAVLOVALES (HAPTOPHYCEAE)1
Authors: Volkman John K. , Farmen Christine L. , Barrett Stephanie M. , Sikes Elisabeth L.
Published: October 2004

Recent studies have led to the identification of an unusual class of dihydroxysterols (steroidal diols termed “pavlovols”)in a few species of microalgae from the genus Pavlova (family Pavlovaceae, class Haptophyceae = Prymnesiophyceae). These compounds have an additional hydroxyl group at G‐4 in the sterol A ring, which appears to be very rare in sterol biosynthetic pathways. The sterol compositions of many other haptophytes from different orders have been analyzed, but to date all have lacked pavlovols. We now report the occurrence of these compounds inDiacronema vlkianumPrauser and two strains ofPavlova pinguisGreen. This is the first report of the lipid composition of these species. Both microalgae contained “24‐methylpavlovol” (4α, 24‐dimethyl‐5α‐cholestan‐3β, 4β‐diol), P. pinguis also contained “24‐ethylpavlovol” (4α‐methyl‐24‐ethyl‐5α‐cholestan‐3β, 4β‐diol), andD. vlkianumcontained a diol identified from its mass spectrum as 4α, 24β‐dimethyl‐5α‐cholest‐22E‐en‐3β,4β‐diol. Both species contained structurally analogous 4‐desmethyl sterols and 4‐methyl sterols, although there were major differences in the proportions in each series. The major 4‐desmethyl sterol in both species was 24‐ethylcholesta‐5, 22E‐dien‐3β‐ol and the major 4‐methyl sterol was 4α‐methyl‐24‐ethyl‐5α‐cholest‐22E‐en‐3β‐ol. The presence of pavlovols inP. pinguis,combined with earlier data, suggests that allPavlovaspecies might have this distinguishing lipid feature. However, their identtjication inD. vlkianumextends the occurrence of these compounds to another genus and shows that they are not unique to the genusPavlova.However, they are probably restricted to species from the order Pavlov ales. The modes of biosynthesis and functions of pavlovols remain unknown.
DESCRIPTION AND CHARACTERIZATION OF THE ALGAL SPECIES AUREOUMBRA LAGUNENSIS GEN. ET SP. NOV. AND REFERRAL OF AUREOUMBRA AND AUREOCOCCUS TO THE PELAGOPHYCEAE1
Authors: DeYoe Hudson R. , Stockwell Dean A. , Biolagare Robert R. , Latasa Mikel , Johnson Paul W. , Hargraves Paul E. , Suttle Curtis A.
Published: October 2004

The Texas brown tide alga (strain TBA‐2) is described as Aureoumbra lagunensis Stockwell, DeYoe, Hargraves, et Johnson, gen. et sp. nov. Pigment composition, chloroplast structure, and 18s ribosomal RNA gene sequence data indicate that A. lagunensis and the east coast brown tide alga Aureococcus anophagefferens (originally placed in the Chrysophyceae) belong in the class Pelagophyceae. The new genus Aureoumbra with A. lagunensis as the type species differs from Aureococcus in 18s ribosomal RNA gene sequence, pyrenoid form, nitrogen physiology, and possession of basal bodies. The genus Aureococcus is placed in the order Pelagomonadates and family Pelagomonadaceae while ordinal placement of Aureoumbra is deferred.
A PRELIMINARY COMPARISON OF RESTRICTION FRAGMENT PATTERNS IN THE GENUS CAULERPA (CHLOROPHYTA) AND THE UNIQUE STRUCTURE OF THE CHLOROPLAST GENOME OF CAULERPA SERTULARIOIDES1
Authors: Lehman Roy L. , Manhart James R
Published: October 2004

Comparisons of chloroplast DNA restriction fragments in four species of Caulerpa revealed that patterns between the species were different, with few and possibly no homologous bands. Two forms of Caulerpa sertularioides also revealed different patterns, and it is possible that the forms are separate species. The chloroplast genome in Caulerpa sertularioides f sertularioides (S. G. Gmelin) Howe is 131.4 kb in size and lacks large repeat units. The discovery of another green‐algal chloroplast genome that lacks an inverted repeat indicates that this feature is either not ancestral to the Chlorophyceae or has been lost several times. Several gene clusters commonly found in chloroplast DNAs were found to occur in Caulerpa chloroplast DNA, for example, psbD/C, atpF/H, and psaA/B. The 16S and 23s rRNA, which are typically adjacent, contained in an inverted repeat, and cotranscribed, are over 40 kb apart. Genes rps12 and tufA, members of the str operon in eubacteria, are over 50 kb in distance from each other in Caulerpa. The gene order in Caulerpa is unlike any other chloroplast genome characterized to date.
The Physics and Physiology of Photosynthesis in Aquatic Ecosystems
Authors: Schofield Oscar , Moline Mark A. , Millie David F.
Published: October 2004

Falkowski, Paul G., and Raven, John A. 1997. Aquatic Photosynthesis.
Serum levels of soluble urokinase plasminogen activator receptor is associated with parasitemia in children with acute Plasmodium falciparum malaria infection
Authors: Perch M. , Kofoed PE. , Fischer T. K. , Có F. , Rombo L. , Aaby P. , Eugen‐Olsen J.
Published: October 2004

Serum levels of soluble urokinase plasminogen activator receptor (suPAR) are significantly elevated and of prognostic value in patients suffering from serious infectious diseases such as HIV and tuberculosis. Our objective was to investigate suPAR levels during symptomatic malaria infection and 7 days after treatment. Children younger than 6 years who presented with fever or other symptoms compatible with malaria were enrolled. Blood films and samples were collected on day 0 and day 7. Twenty‐five children were allocated to each of three groups according to the amount of Plasmodium falciparum detected in their initial blood film. Children in group 1 had parasite densities in excess of 20 parasites per 200 leucocytes. The median plasma suPAR level was 6·49 ng/mL (interquartile range [IQR]: 4·90–7·61) and correlated to parasitemia (Spearman 0·43, P < 0·0001). Blood was obtained from 20 children in group 1 after 7 days of treatment. All became malaria negative in their blood slides and all decreased in suPAR level to median 3·48 ng/mL (IQR: 3·08–3·91) (P < 0·0001). Group 2 consisted of 25 children with 1–20 parasites in their blood slide. The suPAR level was median 2·91 ng/mL (IQR: 2·27–4·40) and decreased with median 0·5 ng/mL following treatment (P = 0·0002). Group 3 showed to be negative in their blood slides and most received antibiotic treatment. suPAR decreased from median 3·26 ng/mL (IQR: 2·77–4·46) to median 2·47 ng/mL (IQR: 2·01–3·75), on day 7 (P = 0·006). This study demonstrates an important association between suPAR and acute malaria infection in humans.
Activation by malaria antigens renders mononuclear cells susceptible to HIV infection and re‐activates replication of endogenous HIV in cells from HIV‐infected adults
Authors: Froebel K. , Howard W. , Schafer J. R. , Howie F. , Whitworth J. , Kaleebu P. , Brown A. L. , Riley E.
Published: October 2004

We have tested the hypothesis that activation of T cells by exposure to malaria antigens facilitates both de novo HIV infection and viral reactivation and replication. PBMC from malaria‐naïve HIV‐uninfected European donors could be productively infected with HIV following in vitro stimulation with a lysate of Plasmodium falciparum schizonts and PBMC from malaria‐naïve and malaria‐exposed (semi‐immune) HIV‐positive adults were induced to produce higher levels of virus after stimulation with the same malaria extract. These findings suggest that effective malaria control measures might con‐tribute to reducing the spread of HIV and extending the life span of HIV‐infected individuals living in malaria endemic areas.
A protective merozoite protein of Plasmodium falciparum shares an epitope with surface antigens of Paramecium
Authors: Sehgal A. , Singh N. J. , Chakraborty T. , Sharma S.
Published: October 2004

A Plasmodium falciparum cDNA expression clone, λPf9, had been identified earlier as a protective epitope, using anti‐λPf9 antibodies and combinatorial phagotopes. A segment of the Pf9 gene showed homology with Paramecium immobilization surface antigens such as 51B, 51A and 156G. A synthetic Pf9‐peptide was designed from this region, and specific antibodies were raised. Each of these anti‐Pf9 antibodies and combinatorial reagents, as well as anti‐Paramecium 51B antibodies, recognized the Pf9‐peptide on ELISA, and the same protein band in parasite immunoblots. The P. falciparum protein was released from the merozoite membrane fraction on treatment with PI‐PLC, indicating the presence of a GPI anchor. Anti‐Pf9‐peptide antibodies specifically inhibited the growth of P. falciparum in culture. Immunofluorescence assays showed the reactivity of anti‐Pf9‐peptide sera with P. falciparum merozoites and gametocytes, as well as on the surface of Paramecium tetraurelia. The Pf9‐peptide was able to induce proliferation of splenic lymphocytes obtained from mice infected with the rodent malarial parasites Plasmodium berghei and Plasmodium yoelii. These results point towards Plasmodium Pf9 as a conserved novel protective protein, sharing an epitope with Paramecium surface antigens.
Entamoeba histolytica cysteine protease 2 (EhCP2) modulates leucocyte migration by proteolytic cleavage of chemokines
Authors: Pertuz Belloso S. , Ostoa Saloma P. , Benitez I. , Soldevila G. , Olivos A. , García‐Zepeda E.
Published: October 2004

Human amoebiasis is a disease produced by infection with the protozoan Entamoeba histolytica currently affecting many millions of people worldwide. Amoebic colitis is the most common clinical manifestation. Host protective immunity involves participation of both humoral and cellular responses. However, the mechanisms involved in immune evasion are not clear and remain under investigation. One of these mechanisms could be associated with the ability of parasite proteases to modulate or interfere with the inflammation process, which is initiated by expression of pro‐inflammatory cytokines such as chemokines. To further clarify the potential role of cysteine proteases in modulating chemokine‐mediated functions, we have analysed the ability of Entamoeba histolytica cysteine protease 2 (EhCP2) to have an effect on the chemotaxis of leucocytes by chemokine cleavage. We find that EhCP2 is capable of cleaving chemokines CCL2, CCL13 and CXCL8, and the resulting proteolysis products modulate the chemotaxis of leucocytes when compared to that induced by intact chemokine. Thus, the extracellular activity of the cysteine proteases affects chemokine‐mediated responses and could be considered as part of the mechanisms used by Entamoeba histolytica to circumvent the host immune responses.
Establishment ofNeospora caninumantigen‐specific T cell lines of primarily CD4+T cells
Authors: Tuo W. , Davis W. C. , Fetterer R. , Jenkins M. , Boyd P. C. , Gasbarre L. C. , Dubey J. P.
Published: October 2004

Neosporosis is an important cause of pregnancy loss in cattle worldwide. Protective immunity againstNeospora caninuminfection may include both cell‐mediated (CMI) and humoral immune responses. This study was to establish short‐term antigen‐specific T cell lines composed of primarily CD4+T cells from peripheral blood lymphocytes (PBL) of infected cows, which may be used to identify immunodominant antigens for the development ofN. caninumvaccines. CrudeN. caninumtachyzoite antigen was prepared fromin vitroderivedN. caninumtachyzoites. Multiple T cell lines were established and maintained for 11 weeks by weekly re‐stimulation withN. caninumantigen and antigen‐presenting cells. All cell lines responded highly to antigen between weeks 3 and 11. Phenotypically, these cells were composed primarily of CD4+T cells between weeks 2–8, with a gradual expansion of gamma/delta+T cells thereafter. The results indicate thatN. caninum‐specific T cell lines can be established and maintained without exogenous T cell growth factors and may be used to identifyN. caninumantigens. This research will enhance our understanding of bovine CMI to neosporosis and may facilitate development of a proven neosporosis vaccine.
Skp2 and p27kip1 expression in melanocytic nevi and melanoma: an inverse relationship*
Authors: Li Qing , Murphy Michael , Ross Jeffrey , Sheehan Christine , Carlson J. Andrew
Published: October 2004

Background:  S‐phase kinase associated protein‐2 (Skp2) ubiquitin ligase p45SKP2 is important in the degradation of p27kip1 (a cyclin dependent kinase inhibitor) and progression through the G1‐S cell‐cycle checkpoint. Low levels of p27 and high levels of Skp2 are related to poor prognosis in some cancers.

Methods:  Clinicopathologic features and immunohistochemical expression of Skp2 and p27kip1 were investigated in 198 melanocytic proliferations: 21 melanocytic nevi, 23 melanoma in situ, 119 primary melanoma, and 35 metastatic melanoma samples. Comparative and survival analyses were performed.

Results:  Progressive and significant increases and decreases in the nuclear expression of Skp2 and p27kip1, respectively, was identified moving from melanocytic nevi (0.05 ± 0.2/85 ± 15) to melanoma in situ (3 ± 2/45 ± 20) to primary cutaneous melanoma (12 ± 9/30 ± 25) to metastatic melanoma (25 ± 15/15 ± 20) (p ≤ 0.006). Expression of these proteins also significantly correlated with increasing American Joint Committee on Cancer (AJCC) T (tumor) classification and AJCC stage (p ≤ 0.01). Moreover, the level of these two proteins exhibited a significant inverse relationship (r = −0.4, p = 0.0001). Skp2 cytoplasmic labeling index of >20% predicted worse 10‐year overall survival (38% vs. 86%, p = 0.04) in primary melanoma. Neither p27 nor Skp2 nuclear expression impacted significantly on prognosis.

Conclusions:  Gain of Skp2 and loss of p27kip1 protein expression are implicated in melanoma progression where the level of p27kip1 may be regulated by targeted proteolysis via Skp2. Cytoplasmic expression of Skp2 defines a subset of aggressive melanomas and could represent another pathway of deregulation of the cell cycle.
Analysis of p53 and bcl‐2 protein expression in the non‐tumorigenic, pretumorigenic, and tumorigenic keratinocytic hyperproliferative lesions
Authors: Hussein Mahmoud R. , Al‐Badaiwy Zaeneb H. , Guirguis Marcelle N.
Published: October 2004

Background:  The hyperproliferative keratinocytic lesions encompass a wide range of non‐tumorigenic, pretumorigenic, and tumorigenic conditions. The aim of this work was to examine the expression patterns of apoptosis‐linked molecules (bcl‐2 and p53) in these lesions.

Methods:  Immunoperoxidase staining methods were applied to analyze p53 and bcl‐2 protein expression in a total of 66 cases, including 12 squamous cell carcinomas (both in situ and invasive SCC), 11 actinic keratoses (AK), 13 psoriasis vulgaris (PV), eight verruca vulgaris (VV), six chronic dermatitis (CD), five seborrheic keratosis (SK), four lichen planus (LP), three epidermodysplasia verruciformis (EDV), two condyloma acuminata (CA), two lichen simplex chronicus (LSC), and 10 specimens from normal skin.

Results:  As compared to normal skin (0.70 ± 0.26), the bcl‐2 average weighted scores in the non‐tumorigenic (0.76 ± 0.16), pretumorigenic (1.45 ± 0.28), and tumorigenic lesions (2.83 ± 0.50 and 2.92 ± 0.50 for in situ and invasive SCC, respectively) showed significant up‐regulation (p = 0.001). In the non‐tumorigenic lesions, the bcl‐2 expression values decreased in the following order: SK > EDV > CD > LP > CA > PV > VV (1.40 ± 0.24 > 1.33 ± 0.67 > 0.83 ± 0.40 > 0.67 ± 0.21 > 0.50 ± 0.20 > 0.46 ± 0.22 > 0.13 ± 0.01, respectively). As compared to normal skin (1.10 ± 0.23), the p53 average weighted scores in the non‐tumorigenic (1.86 ± 0.18), pretumorigenic (3.64 ± 0.53), and tumorigenic lesions (5.00 ± 1.00 and 5.08 ± 0.86 for in situ and invasive SCC, respectively) showed significant up‐regulation (p = 0.021). In the non‐tumorigenic lesions, p53 average weighted scores decreased in the following order: SK > PV > CA > LP > CD > VV > EDV (3.20 ± 0.49 > 2.38 ± 0.27 > 2.0 ± 0.0 > 1.83 ± 0.48 > 1.0 ± 0.37 > 1.0 ± 0.33 > 1.0 ± 0.0, respectively). There was a positive correlation between bcl‐2 and p53 protein expression in normal skin (r = 0.966, p = 0.0001), non‐tumorigenic (r = 0.775, p = 0.0001), pretumorigenic (r = 0.830, p = 0.001), and tumorigenic lesions (r = 0.757, p = 0.003).

Conclusions:  Bcl‐2 and p53 proteins are altered in the keratinocytic hyperproliferative lesions. Determination of whether these alterations reflect underlying gene mutations will require further investigations.
Evaluation of anti‐thrombomodulin antibody as a tumor marker for vascular neoplasms
Authors: Manning Trey , Smoller Bruce R. , Horn Thomas D. , El Darouti Mohammad , Marzouk S. , Hadidi H. E. , Ramadan S.
Published: October 2004

Background:  Various endothelial markers are available for the evaluation of vascular tumors and malformations, including anti CD34, anti‐CD31, von Willebrand factor (vWF), and anti‐thrombomodulin (anti‐TM) antibodies. All have their limitations, and we sought to compare the utility of anti‐TM antibody as a marker for several types of vascular neoplasms vs. previously established endothelial markers.

Methods:  We examined immunostaining profiles of 30 capillary hemangiomas, 10 pyogenic granulomas, five tufted angiomas, 17 Kaposi's sarcomas, and nine angiosarcomas. Immunostains for TM, CD34, and vWF were carried out using a labeled streptavidin–biotin peroxidase detection system.

Results:  Anti‐TM antibody showed moderately intense immunostaining in 89% of benign and malignant vascular neoplasms. Anti‐CD34 antibody showed moderate to diffuse immunostaining in 98% of vascular neoplasms, and vWF showed weak focal staining in 84% of all vascular neoplasms examined.

Conclusion:  Anti‐TM antibody proved to be a sensitive marker for both benign and malignant vascular neoplasms. While not as sensitive as anti‐CD34, it may have some advantages in specificity that would make it a more reliable vascular tumor marker in certain situations.
Gene expression profiling of porokeratosis demonstrates similarities with psoriasis
Authors: Hivnor Chad , Williams Nathan , Singh Fiza , VanVoorhees Abby , Dzubow Leonard , Baldwin Donald , Seykora John
Published: October 2004

Background:  Porokeratosis (PK) is a clinically heterogeneous entity associated with sharply demarcated, annular, or serpiginous lesions with a hyperkeratotic ridge. This disorder is associated with aberrant keratinocyte differentiation that histologically manifests as a stack of parakeratin termed the cornoid lamella; this structure represents the peripheral hyperkeratotic ridge of clinical lesions. Histologically, the keratinocytes forming the cornoid lamella demonstrate an altered differentiation program. However, the molecular basis of PK remains incompletely understood.

Methods:  As a first step in characterizing PK at the molecular level, gene expression profiling was performed on a cornoid lamella isolated from a large, Mibelli‐type porokeratotic lesion. As a control, gene expression profiling of peripheral uninvolved epidermis was also performed. The gene expression profile of cornoid lamellar keratinocytes was compared with similar profiles obtained from a psoriatic plaque and cutaneous squamous cell carcinoma.

Results:  Our study demonstrates a striking similarity between the gene expression profiles of PK and psoriasis. In addition, novel markers of the porokeratotic keratinocytes were identified, including keratin 16, S‐100 A8 and A9, and connexin 26.

Conclusions:  This study supports the hypothesis that PK is a disorder of hyperproliferative keratinocytes exhibiting similarity at the molecular level to psoriasis. Consequently, some therapeutic modalities efficacious for psoriasis may be of benefit in PK.
Heat shock protein 27 is expressed in normal and malignant human melanocytes in vivo
Authors: Kang Steven H. , Fung Maxwell A. , Gandour‐Edwards Regina , Reilly Debra , Dizon Teresa , Grahn Jennifer , Isseroff R. Rivkah
Published: October 2004

Background:  Heat shock proteins (HSPs) are a family of highly conserved proteins found ubiquitously in mammalian cells, believed to be regulators of normal cell physiology and the cellular stress response. In addition, the small 27‐kDa heat shock protein (HSP27) has previously been found to be a differentiation marker for keratinocytes and a prognostic marker associated with increased survival in certain cancerous tumors.

Methods:  Using immunohistochemistry on routinely processed paraffin sections, we examined skin biopsies from 15 invasive melanomas, 13 intradermal nevi, and two compound nevi immunostained with a mouse monoclonal antibody to HSP27. In addition, cultured melanocytes were heat stressed at 45°C for 1 h and then fixed and immunostained in order to localize HSP27 expression intracellularly.

Results:  We found cytoplasmic and strong perinuclear staining of HSP27 in melanocytes in normal skin, in melanomas, and in nevi. Nuclear reactivity was absent. In addition, in cultured non‐malignant melanocytes, HSP27 expression relocated from the cytoplasm to the nucleus with heat stress.

Conclusions:  To our knowledge, this investigation is the first to demonstrate that HSP27 is expressed in melanocytes in normal skin, in nevi, and in non‐malignant cultured melanocytes.
Lymphatic vessel density is significantly increased in melanoma
Authors: Giorgadze T. A. , Zhang P. J. , Pasha T. , Coogan P. S. , Acs G. , Elder D. E. , Xu X.
Published: October 2004

Background:  Melanoma is well known for its ability to involve regional lymph nodes in the early stage. However, the presence of lymphangiogenesis in melanoma is still controversial due to lack of lymphatic‐specific markers. The purpose of this study was to determine the intra‐ and peritumoral lymphatic vessel density (LVD) using a novel lymphatic vessel‐specific marker D2‐40 and compare it to general vessel density (GVD) as determined by CD31 immunostaining in a series of melanocytic lesions.

Methods:  The intra‐ and peritumoral GVD and LVD were examined by immunohistochemistry using D2‐40 and CD31 antibodies in a series of melanocytic lesions.

Results:  We found significantly higher intratumoral LVD in melanomas as compared to either common acquired or dysplastic nevi (p < 0.01). Although peritumoral LVD in melanoma and malignant melanoma in situ was higher compared to nevi, the difference did not reach statistical significance (p = 0.059). There was no significant difference in GVD among the various groups of melanocytic lesions.

Conclusions:  Our results show that intratumoral LVD is significantly increased in melanomas compared to benign nevi. The higher intratumoral lymphatic density in invasive melanomas suggests that melanoma cells might promote lymphangiogenesis. In addition, assessment of intratumoral LVD may be potentially useful in the differential diagnosis of melanocytic lesions.
Three‐Dimensional Transesophageal Echocardiographic Delineation of Ventricular Septal Aneurysm Producing Right Ventricular Outflow Obstruction in an Adult
Authors: Baweja Gurpreet , Nanda Navin C. , Nekkanti Rajshekhar , Dod Harvinder , Ravi Barugur , Fadel Ahmed
Published: October 2004

We report three‐dimensional echocardiographic delineation of a congenital aneurysm of the membranous interventricular septum causing right ventricular outflow tract obstruction in an adult patient. To our knowledge, these findings have not been described before. (ECHOCARDIOGRAPHY, Volume 21, January 2004)