bluuebunny/crossref_metadata_2025 huggingface dataset:
The Frequency Of Arterial Hypertension Versus Orthostatic Hypotension In Diabetic Patients
Authors: Ionescu‐Tîrgoviste C , Tinu Am , Mircea E , Guja C , Vasilescu R , Cristescu J , Bratu D.
Published: March 2003

Aim: The aim of this study was to assess the relationship between supine high blood pressure and orthostatic hypotension both in Type 1 (T1DM) and Type 2 (T2DM) diabetic patients. Patients and Methods: Our study included 321 T2DM patients (153 M/168 F; mean age 62.3 (14.2 yr; duration of disease 12.1 (7.6 yr) and 116 T1DM patients (65 M/51 F; mean age 39.7 (9.2 yr; duration of diabetes 11.9 (8.1 yr). Patients with orthostatic hypotension were divided into 3 groups: A – without symptoms; B – mild/moderate symptoms (short and tolerable dizziness when standing); C – severe symptoms (persistent and disabling dizziness or even fainting in upright position). Results: Arterial hypertension was registered in 67.6% of T2DM patients (217 from 321 cases) and in 50.0% of T1DM patients (58 from 116 cases). Orthostatic hypotension (defined as a decrease in systolic blood pressure (30 mm Hg)) was encountered in 64.5% in T2DM patients (207 out of 321 cases) and in 60.3% of T1DM patients (70 out of 116 cases). From 207 T2DM patients with orthostatic hypotension, 105 were in Group A (50.7%), 89 in Group B (42.99%) and 13 in Group C (6.28%), while from 70 T1DM patients with orthostatic hypotension 14 were in Group A (20.0%), 51 in Group B (72.8%) and 5 in Group C (7.14%). An association of supine arterial hypertension with orthostatic hypotension was registered in 96 (29.9%) T2DM patients (68 of them receiving antihypertensive treatment) and in 25 (21.5%) T1DM patients (19 of which were on antihypertensive treatment). From the 18 patients with severe orthostatic hypotension (13 T2DM and 5 T1DM), supine arterial hypertension was registered in 5 cases (3 T2DM and 2 T1DM). In 4 of these 5 cases, patients were receiving antihypertensive treatment. Discontinuation of this treatment led to a decrease in the intensity of clinical signs of orthostatic hypotension in 4 out of 5 cases. An improvement of clinical symptoms of orthostatic hypotension was recorded in about 1/3 of hypertensive patients after discontinuation or just lowering of the dose of antihypertensive drugs (26 out of 87 cases). Conclusion: An association between hypertension and orthostatic hypotension is frequent both in T1DM and in T2DM, rising in difficulties for treatment. The treatment of hypertension in diabetic patients should take into account the possible orthostatic hypotension induced by some of the antihypertensive drugs.
Quality Of Life In Patients With Cryoglobulinemic Polyneuropathy
Authors: Ferraris A , Inglese C , Giuberti T , Cocca G , Melli G , Marbini A , Gemignani F.
Published: March 2003

The assessment of severity of polyneuropathy is usually based on the findings of neurological and electrophysiological examination, which however do not reflect overall function. Health‐related quality of life (HRQOL) measurements aim to measure the impact of a disease on the daily life of a patient, and are expecially useful in chronic diseases, however are seldom used in neuromuscular diseases. It was previously reported that HRQOL assessment may be useful in diabetic neuropathy, chronic idiopathic axonal polyneuropathy, and Charcot‐Marie‐Tooth disease. The aim of this study was to determine whether HRQOL is reduced in cryoglobulinemic polyneuropathy, and whether its measurements add useful information to the assessment of severity of polyneuropathy. We studied 12 patients (10 females, 2 males) with symptomatic cryoglobulinemic neuropathy (HCV‐related in all patients but 1), confirmed by neurophysiological study, and 10 non‐neuropathic patients (4 females, 6 males) with HCV‐related mixed cryoglobulinemia. HRQOL was assessed using the self‐administered 36‐item Short Form Health Survey Questionnaire (SF‐36). The neuropathy patients had lower scores (impaired HRQOL) than the other cryoglobulinemic patients on “physical functioning”, “pain”, and “vitality.” Both neuropathic and non‐neuropathic patients with cryoglobulinemia rated worse than the reference population on “role limitation due to physical problems” and “general health perception.” We conclude that the severity of neuropathy may be measured with a general HRQOL instrument, which provides additional information about the impact of the disease on the general functioning of the patient, and it may be useful in rehabilitation and counseling of neuropathic patients.
Expression Of The Co‐Stimulatory Molecule BB‐1, The Ligands CTLA‐4 and CD28 and Their Mrnas In Chronic Inflammatory Demyelinating Polyneuropathy
Authors: Murata K , Dalakas MC
Published: March 2003

To examine whether the Schwann cells in patients with autoimmune neuropathies have the potential to behave as professional antigen‐presenting cells, we investigated the expression of the co‐stimulatory molecules BB‐1, B7‐1 (CD80), B7‐2 (CD86) and their counter‐receptors CD28 or CTLA‐4 (CD152) at the protein and mRNA levels in sural nerve biopsies of patients with chronic inflammatory demyelinating polyneuropathy (CIDP), CIDP associated with human immunodeficiency virus infection (HIV‐CIDP), IgM paraproteinaemic neuropathy and normal or non‐immune axonal neuropathy. In single‐and double‐labelling experiments, we used the S‐100 antigen as a pan‐Schwann cell marker, myelin‐associated glycoprotein as a marker for myelinating Schwann cells and the fibrillary acidic protein as a marker for unmyelinating Schwann cells. The expression of the B7 family of molecules was limited to BB‐1 and was observed only on the Schwann cells. There was constitutive expression of BB‐1 on unmyelinating Schwann cells in all nerves studied. However, in CIDP and HIV‐CIDP, but not the other diseases, there was prominent upregulation of BB‐1 on the myelinating Schwann cells. The endoneurial T cells in the proximity of BB‐1‐positive Schwann cells expressed the CD28 or CTLA‐4 counterreceptors. Reverse transcription‐polymerase chain reaction confirmed that these ligands were upregulated only in CIDP. Because the myelinating BB‐1‐positive Schwann cells expressed HLA‐DR antigen, the findings indicate that, in CIDP, Schwann cells possess the necessary markers to function as antigen‐presenting cells.
The effect of hyperbaric oxygen treatment on early regeneration of sensory axons after nerve crush in the rat
Authors: Bajrović Fajko F. , Sketelj Janez , Jug Marko , Gril Iztok , Mekjavić Igor B.
Published: March 2003

Abstract  The effect of hyperbaric oxygen treatment (HBO) on sensory axon regeneration was examined in the rat. The sciatic nerve was crushed in both legs. In addition, the distal stump of the sural nerve on one side was made acellular and its blood perfusion was compromised by freezing and thawing. Two experimental groups received hyperbaric exposures (2.5 ATA) to either compressed air (pO2 = 0.5 ATA) or 100% oxygen (pO2 = 2.5 ATA) 90 minutes per day for 6 days. Sensory axon regeneration in the sural nerve was thereafter assessed by the nerve pinch test and immunohistochemical reaction to neurofilament. HBO treatment increased the distances reached by the fastest regenerating sensory axons by about 15% in the distal nerve segments with preserved and with compromised blood perfusion. There was no significant difference between the rats treated with different oxygen tensions. The total number of regenerated axons in the distal sural nerve segments after a simple crush injury was not affected, whereas in the nerve segments with compromised blood perfusion treated by the higher pO2, the axon number was about 30% lower than that in the control group. It is concluded that the beneficial effect of HBO on sensory axon regeneration is not dose‐dependent between 0.5 and 2.5 ATA pO2. Although the exposure to 2.5 ATA of pO2 moderately enhanced early regeneration of the fastest sensory axons, it decreased the number of regenerating axons in the injured nerves with compromised blood perfusion of the distal nerve stump.
Quantitative sensory testing: high sensitivity in small fiber neuropathy with normal NCS/EMG
Authors: Magda Paul , Latov Norman , Renard Michelle V. , Sander Howard W.
Published: March 2003

Abstract  We evaluated the diagnostic sensitivity of quantitative sensory testing (QST), using the CASE IV system, in 14 patients with clinically diagnosed small‐fiber neuropathy and normal traditional electrodiagnostic studies. All patients had at least 1 abnormal threshold, 13 patients had abnormal heat‐pain thresholds, 8 had abnormal cold thresholds, and 7 had abnormal vibration thresholds. QST is therefore highly effective in documenting dysfunction in small fiber neuropathy patients.
THERAPEUTIC POTENTIAL OF PKC INHIBITORS IN PAINFUL DIABETIC NEUROPATHY
Authors: Kamei J , Mizoguchi H , Narita M , Tseng LF.
Published: March 2003

Diabetic neuropathy accompanied by anomalies in pain perception is one of the most frequent complications in insulin‐dependent diabetes in humans. Many clinical and experimental studies have suggested that diabetes or hyperglycaemia alters pain sensitivity. In humans, diabetic neuropathy can be associated with burning, tactile hypersensitivity. Behavioural reactions of hyperalgesia in animal models of diabetes have been described. However, the aetiology of these disturbances is still unknown, although metabolic factors such as hyperglycaemia or neurotransmitter alteration may be involved. Activation of protein kinase C (PKC) has been implicated in changes in pain perception. Phorbol esters, which activate PKC, enhance the thermal hyperalgesia in diabetic mice and enhance nociceptive responses after tissue injury induced by formalin. Electrophysiological experiments have shown that activation of PKC leads to long‐lasting enhancement of excitatory amino acid‐mediated currents in dorsal horn neurons and trigeminal neurons. Thus, activation of PKC may underlie the neuronal sensitisation that produces hyperalgesia in diabetic neuropathy.
LATE‐ONSET GM2 GANGLIOSIDOSIS PRESENTING AS BURNING DYSESTHESIAS
Authors: Chow GCS , Clarke JTR , Banwell BL.
Published: March 2003

Two brothers with a painful neuropathy as a component of late‐onset GM2 gangliosidosis of the Sandhoff type are presented. A dramatic response of the severe dysesthesias to amitriptyline and gabapentin is described. Symptomatic sensory neuropathy may be a component of late‐onset GM2 gangliosidosis.
MINIREVIEW—POLYPHENOLS AND OXIDASES IN SUBSTRATUM ADHESION BY MARINE ALGAE AND MUSSELS
Authors: Vreeland Valerie , Waite J. Herbert , Epstein Lynn
Published: March 2003

Minireviews do not have abstracts.
BRYOZOANS INCREASE AVAILABLE CO2 FOR PHOTOSYNTHESIS IN GELIDIUM SESQUIPEDALE (RHODOPHYCEAE)
Authors: Mercado Jesús M. , Carmona Raquel , Niell F. Xavier
Published: March 2003

A possible benefit of the presence of the epiphytic bryozoan Electra pilosa (L.) for the red macroalga Gelidium sesquipedale (Clem.) Thuret et Bornet is described. Absorption spectra and photosynthetic parameters of O2 evolution vs. irradiance curves were determined for both epiphytized and nonepiphytized thalli. The absorptance of G. sesquipedale thalli for PAR was not modified by the presence of the epiphyte. Gross photosynthetic rates at saturating light were approximately doubled in epiphytized thalli. Photosynthesis by G. sesquipedale was enhanced when CO2 concentration was increased in the medium by a decrease in pH. On the other hand, an increase in pH from 8.1 to 8.7 produced a significant reduction of the O2 evolution rates indicating that G. sesquipedale has a very low capacity to use HCO3−. The decrease in photosynthesis at high pH was higher in nonepiphytized thalli than in epiphytized ones, suggesting that the amount of available CO2 is higher in the presence of E. pilosa. This positive effect was attributed to the CO2 released by respiration of the epiphyte.
AXENIC TISSUE CULTURE AND MORPHOGENESIS IN PORPHYRA YEZOENSIS (BANGIALES, RHODOPHYTA)
Authors: Yamazaki Ayano , Nakanishi Koichi , Saga Naotsune
Published: March 2003

To better understand developmental phenomena in macroalgal tissue culture, we examined the morphogenesis of Porphyra yezoensis Ueda (strain TU‐1) cultured aseptically in defined synthetic media. Generally, the filamentous thalli (sporophyte; conchocelis phase) of P. yezoensis were densely tufted with uniseriate filaments. The foliose thalli (gametophyte) were monolayered. In this study, axenic filamentous thalli retained their characteristic morphogenesis; there were no obvious differences between morphogenetic traits in unialgal and axenic conditions. However, conchospores, which might have developed into the foliose form under unialgal conditions, germinated into calluslike masses under axenic conditions. Most of the gametophytes gradually lost their typical morphogenesis after the first longitudinal cell division. Some of the calluslike masses developed rhizoidlike structures in several places or along the entire mass. Therefore, we concluded that P. yezoensis, in axenic cultures, loses its typical morphogenesis only during the gametophytic phase. The axenic tissue culture of Porphyra established in this study is a promising assay system for the identification of growth and morphogenetic factors.
ALGICIDAL BACTERIA ACTIVE AGAINST GYMNODINIUM BREVE (DINOPHYCEAE). I. BACTERIAL ISOLATION AND CHARACTERIZATION OF KILLING ACTIVITY1,3
Authors: Doucette Gregory J. , McGovern Elizabeth R. , Babinchak John A.
Published: March 2003

Interactions between bacteria and species of harmful and/or toxic algae are potentially important factors affecting both the population dynamics and the toxicity of these algae. Recent reports of bacteria lethal to certain harmful algal bloom (HAB) species, coupled with a rapidly evolving interest in attempting to minimize the adverse effects of HABs through various prevention, control, and mitigation strategies, have focused attention on defining the role of algicidal bacteria in bloom termination. The aim of the present study was to determine whether algicidal bacteria active against Gymnodinium breve Davis, a dinoflagellate responsible for frequent and protracted red tides in the Gulf of Mexico, are present in the waters of the west Florida shelf. To date, we have isolated two bacterial strains from this region lethal to G. breve and have begun to characterize the algicidal activity of one of these strains, 41‐DBG2. This bacterium, a yellow‐pigmented, gram‐negative rod, was isolated from waters containing no detectable G. breve cells, suggesting that such bacteria are part of the ambient microbial community and are not restricted to areas of high G. breve abundance. Strain 41‐DBG2 produced a dissolved algicidal compound(s) that was released into the growth medium, and the algicide was effective against the four Gulf of Mexico G. breve isolates tested as well as a closely related HAB species that also occurs in this region, Gymnodinium mikimotoi Miyake et Kominami ex Oda. Nonetheless, data showing that a nontoxic isolate of Gymnodinium sanguineum Hirasaka from Florida Bay was not affected indicate that the algicidal activity of this bacterium does exhibit a degree of taxonomic specificity. Our efforts are currently being directed at resolving several critical issues, including the identity of the algicide(s), the mechanisms regulating its production and ability to discriminate between target algal species, and how the growth rate of 41‐DBG2 is affected by the presence of G. breve cells. We have also proposed a conceptual model for interactions between algicidal bacteria and their target species to serve as a testable framework for ensuing field studies.
CpKLP1: A CALMODULIN‐BINDING KINESIN‐LIKE PROTEIN FROM CYANOPHORA PARADOXA (GLAUCOPHYTA)
Authors: Abdel‐Ghany Salah E. , Kugrens Paul , Reddy A. S. N.
Published: March 2003

KCBP (kinesin‐like calmodulin [CaM]‐binding proteins), a member of the carboxy‐terminal kinesin‐like proteins (KLPs), is unique among KLPs in having a CaM‐binding domain (CBD). CaM‐binding KLPs have been identified from flowering plants and the sea urchin. To determine if CaM‐binding KLP is present in phylogenetically divergent protists, we probed Cyanophora paradoxa protein extract with affinity‐purified KCBP antibody. The KCBP antibody detected a polypeptide with a molecular mass of about 133 kDa in the crude extract. In a CaM–Sepharose column‐purified fraction, the same band was detected with both KCBP antibody and biotinylated CaM. In a PCR reaction using degenerate primers corresponding to two conserved regions in the motor domain of kinesin, a 500‐bp fragment (CpKLP1) was amplified from a cDNA library. The predicted amino acid sequence of CpKLP1 showed significant sequence similarity with KCBPs. In phylogenetic analysis, CpKLP1 fell into the KCBP group within the carboxy‐terminal subfamily. These biochemical data, sequence, and phylogenetic analysis strongly suggest the presence of a calmodulin‐binding KLP in C. paradoxa and that it is related to Ca2+/calmodulin regulated KLPs from plants. This is the first report on identification of any motor protein in C. paradoxa. Furthermore, our data suggest that CaM‐binding KLPs may have evolved long before the divergence of plants and animals.
Effects of temperature on the photoreactivation of ultraviolet‐b–induced dna damage in Palmaria palmata (Rhodophyta)
Authors: Pakker Hans , Martins Rute S. T. , Boelen Peter , Buma Anita G. J. , Nikaido Osamu , Breeman Anneke M.
Published: March 2003

The accumulation of DNA damage (thymine dimers and 6‐4 photoproducts) induced by ultraviolet‐B radiation was studied in Palmaria palmata (L.) O. Kuntze under different light and temperature conditions, using specific monoclonal antibodies and subsequent chemiluminescent detection. Both types of damage were repaired much faster under ultraviolet‐A radiation (UVAR) plus photosynthetically active radiation (PAR) than in darkness, which indicates photoreactivating activity. At 12° C, all thymine dimers were repaired after 2 h irradiation with UVAR plus PAR, whereas 6‐4 photoproducts were almost completely repaired after 4 h. After 19 h of darkness, almost complete repair of 6‐4 photoproducts was found, and 67% of the thymine dimers were repaired. In a second set of experiments, repair of DNA damage under UVAR plus PAR was compared at three different temperatures (0, 12, and 25° C). Again, thymine dimers were repaired faster than 6‐4 photoproducts at all three temperatures. At 0° C, significant repair of thymine dimers was found but not of 6‐4 photoproducts. Significant repair of both thymine dimers and 6‐4 photoproducts occurred at 12 and 25° C. Optimal repair efficiency was found at 25° C for thymine dimers but at 12° C for 6‐4 photoproducts, which suggests that the two photorepair processes have different temperature characteristics.
CADMIUM AND ZINC BIOAVAILABILITY TO SELENASTRUM CAPRICORNUTUM (CHLOROPHYCEAE): ACCIDENTAL METAL UPTAKE AND TOXICITY IN THE PRESENCE OF CITRATE
Authors: Errécalde Olivier , Campbell Peter G. C.
Published: March 2003

Toxicities of cadmium (Cd) and zinc (Zn) to the green alga Selenastrum capricornutum Printz were determined over 72 h in defined synthetic media buffered by citrate (FRAQCIT ; [citrate] = 100 μM or 5 μM) or nitrilotriacetate (FRAQNTA ; [NTA] = 5 μM). Algal sensitivity to free Cd2+ or free Zn2+ in FRAQCIT was much higher than in FRAQNTA. In parallel experiments, short‐term intracellular uptake of radiolabeled 109Cd was measured as a function of time (0–30 min) in FRAQCIT and FRAQNTA; for a given free Cd2+ concentration (8, 250, or 610 nM), intracellular accumulation of Cd was consistently higher in FRAQCIT than in FRAQNTA. Under the same conditions, the alga accumulated 14C‐labeled citrate almost linearly over a 2‐h period. Loss of 109Cd from algal cells that had been prelabeled with the radionuclide occurred slowly, and the loss rate was insensitive to the presence or absence of citrate, indicating that the overall permeability of the algal membrane to Cd was unaffected by citrate. The enhanced bioavailability of Cd in the presence of citrate could be explained by membrane transport of a charged Cd–citrate complex, presumably by accidental transport.
Phylogenetic analyses of 18s rdna sequences reveal a new coccoid lineage of the prasinophyceae (Chlorophyta)
Authors: Fawley Marvin W. , Yun Yue , Qin Mingbo
Published: March 2003

Phylogenetic analyses of 18S rDNA sequences from 25 prasinophytes, including 10 coccoid isolates, reveals that coccoid organisms are found in at least three prasinophyte lineages. The coccoid Ostreococcus tauri is included in the Mamiellales lineage and P ycnococcus provasolii is allied with the flagellate P seudoscourfieldia marina. A previously undescribed prasinophyte lineage is comprised of the coccoid Prasinococcus cf. capsulatus (CCMP 1407) and other isolates tentatively identified as Prasinococcus sp. (CCMP 1202, CCMP 1614, and CCMP 1194), as well as three unnamed coccoids (CCMP 1193, CCMP 1413, and CCMP 1220). No flagellate organisms are known from this lineage. Organisms of this new lineage share some characteristics of both the Pycnococcaceae and the Mamiellales, although relationships among these separate lineages were not supported by bootstrap analyses. An additional unnamed coccoid isolate (CCMP 1205) is separate from all major prasinophyte lineages. The analyses did not resolve the relationships among the major prasinophyte lineages, although they support previous conclusions that the Prasinophyceae are not monophyletic.
THE USE OF INTERFERENCE REFLECTION CONTRAST IN THE EXAMINATION OF DIATOM VALVES
Authors: Siver Peter A. , Hinsch Jan
Published: March 2003

Even though scanning electron microscopy (SEM) is now needed to identify some species of diatoms, the majority of identifications and quantification of these organisms in ecological works is accomplished with a light microscope, using transmitted light optical methods. In this paper we demonstrate the use of interference reflection contrast (incident light) for the examination of diatoms, a method that significantly improves the resolution of structural detail, and therefore, identification of diatom taxa with light microscopy. Using incident light we were routinely able to distinguish between structures that were close to the theoretical limit of resolution for visible light, and that were not resolvable with such standard transmitted light techniques as phase contrast and differential interference contrast (DIC). Light microscopes with epi‐illumination light paths can be easily and inexpensively outfitted to use this simple technique.

Abbreviations: DIC, differential interference contrast; IRC, interference reflection contrast; LM, light microscopy
Cell ultrastructural changes correlate with circadian rhythms inPyrocystis lunula(Pyrrophyta)
Authors: Seo Kyung Suk , Fritz Lawrence
Published: March 2003

Pyrocystis lunula(Schutt) Schutt has long been a model cell system in the study of circadian rhythms of bioluminescence and photosynthesis. Despite this, relatively little is known about the cell's ultrastructure. Here we report the complete serial reconstruction ofP. lunulacells during both day and night phases (the first four dimensional study of any dinoflagellate). This permitted us to track both positional and ultrastructural changes in plastids and scintillons (the organelles responsible for bioluminescence). In daytime cells, plastids extended radially from the cell center with thylakoid membranes in stacks of two. Daytime scintillons clustered in a central region of the cell surrounded by the C‐shaped nucleus. During the night, plastids were closely associated in the cell center with their thylakoids stacked in a grana‐like arrangement. Nighttime scintillons were spread into the cell periphery. The daily migration of plastids and scintillons may depend on these organelles' interactions with the cells' cytoskeletal framework and appears to be under control of the circadian clock.
FACTORS INFLUENCING DIATOM DISTRIBUTIONS IN CIRCUMPOLAR TREELINE LAKES OF NORTHERN RUSSIA
Authors: Laing Tamsin E. , Smol John P.
Published: March 2003

Diatom assemblages and limnological data were analyzed from 74 lakes spanning arctic treeline in three geographical regions of northern Russia: near the mouth of the Pechora River, on the Taimyr Peninsula, and near the mouth of the Lena River. Analysis of similarities indicated that diatom assemblages in tundra and forest lakes were significantly different from each other in all regions, with tundra lakes generally associated with higher abundances of small benthic Fragilaria Lyngbye taxa. Canonical correspondence analysis identified variables related to ion concentrations (e.g. Na+, dissolved inorganic carbon), lake depth, silica concentrations, and surface water temperatures as factors that explained significant amounts of variation in the diatom assemblages. Across treeline, the generally higher surface water temperatures of the forested lakes consistently accounted for a significant proportion of the diatom distribution patterns. Major ion concentrations also explained significant amounts of variation in the diatom assemblages across treeline for all three regions; however, regional trends were most likely influenced by local factors (i.e. ocean proximity or anthropogenic activities). The importance of climatic gradients across treeline (e.g. temperature) diatom distributions provides additional evidence that diatoms may be useful as paleoclimatic indicators. However, combination of the three calibration sets revealed that local water chemistry determinants (e.g. lithology, marine influence) overrode the influence of climatic gradients in explaining diatom distributions, suggesting that regional differences must be minimized for successful combination of geographically separate calibration sets.
GRAZING AND GROWTH OF THE MIXOTROPHIC CHRYSOMONAD POTERIOOCHROMONAS MALHAMENSIS (CHRYSOPHYCEAE) FEEDING ON ALGAE
Authors: Zhang Xiaoming , Watanabe Makoto M.
Published: March 2003

The growth and grazing characteristics of Poterioochromonas malhamensis (Pringsheim) Peterfi (= Ochromonas malhamensis Pringsheim) (ca. 8 μm) feeding on phytoplankton, including the cyanobacteria Synechococcus sp. (ca. 2 μm) and Microcystis viridis (A. Brown) Lemmermann (ca. 6 μm) and the green alga Chlorella pyrenoidosa Chick (ca. 13 μm), were investigated in laboratory experiments involving the following treatments: (1) light without added algal prey (autotrophy), (2) light with added algal prey (mixotrophy), and (3) dark with added algal prey (phagotrophy). There were significantly higher cell numbers under mixotrophic and phagotrophic growth than under autotrophic growth. With phytoplankton as food, growth rates under both mixotrophy and phagotrophy were about two or three times higher than those under autotrophy, indicating that the algal diets were readily able to support the population growth of P. malhamensis. There were no significant differences in growth rate between mixotrophic and phagotrophic cultures during exponential growth. The ingestion rate of P. malhamensis with algal prey was also similar under both continuous light and dark. Poterioochromonas malhamensis ingested on average 0.27 M. viridis cells·flagellate−1·h−1 and 0.18 C. pyrenoidosa cells·flagellate−1·h−1 in continuous light and 0.25 M. viridis cells·flagellate−1·h−1 and 0.18 C. pyrenoidosa cells·flagellate−1·h−1 in continuous dark during exponential growth. The results showed that light had no effect on the growth and ingestion rates of P. malhamensis for phagotrophy during exponential growth. However, phagotrophic populations of P. malhamensis were incapable of growth in continuous darkness for longer than 5 days. Populations of P. malhamensis showed no increase when prey was added again after 4 days in continuous darkness, indicating that light is necessary for sustained phagotrophic growth of P. malhamensis. The study suggests that P. malhamensis, which has strong tolerance for light, is light dependent for phagotrophy.
LIFE HISTORY PHASES AND THE BIOMECHANICAL PROPERTIES OF THE RED ALGA CHONDRUS CRISPUS (RHODOPHYTA)
Authors: Carrington Emily , Grace Sean Patrick , Chopin Thierry
Published: March 2003

Chondrus crispus Stackhouse alternates between two isomorphic life history phases that differ in cell‐wall phycocolloid composition. It has been long hypothesized that the gametophyte, with strong‐gelling kappa‐type carrageenans, is mechanically superior to the tetrasporophyte, with nongelling lambda‐type carrageenans, which could contribute to the observed gametophytic dominance in many wave‐swept environments. Standard mechanical tests were performed on distal tissues of C. crispus sampled from a range of environments in Narragansett Bay, Rhode Island, using a tensometer equipped with a video extensometer. Life history phase was by far the most important determinant of mechanical properties, whereas environmental factors had only modest influence (vertical distribution) or no effect (exposure); gametophytic distal tissues were 43% stronger, 21% more extensible, and 21% stiffer than tetrasporophytic distal tissues. However, the superior strength of gametophytic tissues was not evident at the stipe/holdfast junction (where breakage typically occurs), and the two phases were equally susceptible to dislodgment by a given force. The primary ecophysiological role of carrageenans in C. crispus may not be the provision of a structure to resist wave action.
CHEMISTRY, PROPERTIES, AND PHYLOGENETIC IMPLICATIONS OF THE METHYLATED CARRAGEENANS FROM RED ALGAE OF THE GENUS ARESCHOUGIA (ARESCHOUGIACEAE, GIGARTINALES, RHODOPHYTA)
Authors: Chiovitti Anthony , Kraft Gerald T. , Bacic Antony , Craik David J. , Liao Ming‐Long
Published: March 2003

The three Australian‐endemic species comprising the genus Areschougia have been examined to determine the structure of their nonfibrillar wall components. The polysaccharide extracted from the most widely distributed species, A. congesta (Turner) J. Agardh, was shown by compositional analyses, Fourier transform infrared (FTIR) spectroscopy, linkage analysis, and 13C‐NMR spectroscopy to be a carrageenan composed predominantly of the repeating disaccharides 6′‐O‐meth‐ ylcarrabiose 2,4′‐disulfate, carrabiose 2,4′‐disulfate (the repeating unit of ι‐carrageenan), 4′,6′‐O‐(1‐carboxyethylidene)carrabiose 2‐sulfate, and 6′‐O‐methylcarrabiose 2‐sulfate. The carrageenan also contained small amounts of 4‐linked Galp residues, some bearing methyl ether substitution at O‐3 and some possibly bearing sulfate ester and/or glycosyl substitutions at O‐3. The A. congesta carrageenan had unique rheological properties, its gels having some similarities to those of commercial ι‐carrageenan but with the viscosity of commercial λ‐carrageenan. Polysaccharides from A. ligulata Harvey ex J. Agardh and A. stuartii Harvey were shown by constituent sugar and FTIR analyses to be sulfated galactans rich in mono‐O‐methylgalactose. The carrageenan structures of Areschougia spp. were consistent with those of the genera Rhabdonia, Erythroclonium, and Austroclonium, the other genera constituting the family Areschougiaceae.
PHYLOGENY OF THE DUMONTIACEAE (GIGARTINALES, RHODOPHYTA) AND ASSOCIATED FAMILIES BASED ON SSU rDNA AND INTERNAL TRANSCRIBED SPACER SEQUENCE DATA
Authors: Tai Vera , Lindstrom Sandra C. , Saunders Gary W.
Published: March 2003

Small subunit (SSU) rDNA was sequenced for 25 species in 19 genera of the Gigartinales (Rhodophyta). As well, the internal transcribed spacer (ITS) region was sequenced, and a data matrix of 36 morphological characters was constructed for 16 species of Dumontiaceae. Phylogenetic trees were calculated from a multiple alignment of the SSU sequence data to infer relationships between species of Dumontiaceae and other gigartinalean taxa. The SSU analysis produced a polyphyletic Dumontiaceae. Notably, Acrosymphyton failed to associate with the included Gigartinales, let alone the Dumontiaceae, supporting an earlier proposal to remove it to a new family. The analyses were equivocal about the phylogenetic affinities of Dudresnaya, which clustered with the Kallymeniaceae, and the affinities of the Indo‐West Pacific Gibsmithia, Kraftia, and Dasyphloea, the last‐mentioned clustering with the Antarctic Gainiaceae, and these four taxa with Portieria (Rhizophyllidaceae). Further investigations are necessary to resolve relationships among these taxa. Rhodopeltis, a genus recently moved to the Dumontiaceae from the Polyideaceae, showed a weak association with the remaining northern Dumontiaceae. The final group consisted of cold‐temperate Northern Hemisphere species. Phylogenetic analyses using a combination of SSU, ITS, and morphological data within this clade produced two strongly supported clades, a Dilsea/Neodilsea clade and a Cryptosiphonia/Dumontia clade. Dilsea is derived from a paraphyletic Neodilsea and may itself be polyphyletic. Atlantic and Pacific isolates of Dumontia contorta clearly showed sufficient divergence to warrant recognition as distinct species, and Dumontia alaskana, sp. nov. is proposed for the Pacific species.
SMALL CELL AND INTERMEDIATE CELL FORMATION IN SPECIES OFDINOPHYSIS(DINOPHYCEAE, DINOPHYSIALES)
Authors: Reguera Beatriz , González‐Gil Sonsoles
Published: March 2003

Observations of two distinct size classes with similar shape in natural populations ofDinophysisEhrenberg were first reported by Jorgensen in 1923 and intermediate forms exhibiting a continuum between the typical vegetative cell and a putative small cell by Wood in 1954. Focused attention onDinophysisspp. associated with diarrhetic shellfish intoxications in the last decade has provided new examples of small cells in the genus, sometimes with contours dissimilar from the corresponding vegetative cells; dimorphic individuals; and large/small cell couplets. This work was based onin situobservations during intensive sampling for cell cycle studies ofDinophysis acuminataClaparéde et Lachmann,Dinophysis acutaEhrenberg,Dinophysis caudataSaville‐Kent, andDinophysis triposGourret; on laboratory incubations ofD. acuminata;and on a thorough search of documented information on morphological variability ofDinophysisspp. Duringin situdivision, most dividing cells exhibit a normal longitudinal fission, but some (1%–10%) undergo a “depauperating” fission, leading to pairs of dimorphic cells with dissimilar moieties. After separation and sulcal list regeneration, these dimorphic cells becomeD. skagiiPaulsen,D. densPavillard,D. diegensisKofoid, andD. diegensisKofoid var.curvata‐like individuals, which can also be observed forming coupletsD. acuminata/D. skagii,D. acuta/D. dens, andD. caudata/D. diegensisattached by their ventral margins. Small cells can grow again to large size, as shown in laboratory incubations ofD. acuminata, thus partly explaining observations of thecal intercalary bands, and intermediate forms. The sexual nature of the small cells will not be unequivocally demonstrated until controlled germination of the alleged cyst forms is achieved, and some intermediate forms may correspond to undescribed stages after cyst germination. These observations suggest common patterns in the life cycle ofDinophysisspp. Intraspecific morphological variability ofDinophysisspp. in a given geographic area can largely be attributed to small cell formation, as a response to changing environmental conditions, and may be a part of the sexual cycle of these species. Small cells seem to be able to enlarge, leading to intermediate cell and further vegetative cell formation as part of a three‐looped life history pattern inDinophysis.
FROM PROTOPLASM TO SWARMER: REGENERATION OF PROTOPLASTS FROM DISINTEGRATED CELLS OF THE MULTICELLULAR MARINE GREEN ALGA MICRODICTYON UMBILICATUM (CHLOROPHYTA)1
Authors: Kim Gwang Hoon , Klotchkova Tatiana A. , West John A.
Published: March 2003

Protoplast regeneration from extruded cytoplasm of the multicellular marine green alga Microdictyon umbilicatum (Velley) Zanardini (Cladophorales, Anadyomenaceae) was investigated. The early process of protoplast formation is comprised of two steps: agglutination of cell organelles into protoplasmic masses followed by generation of a temporary enclosing envelope around them. Agglutination of cell organelles was mediated by a lectin–carbohydrate complementary system. Three sugars, D‐galactosamine, D‐glucosamine, and α‐D‐mannose, inhibited the agglutination process, and three complementary lectins for the above sugars, peanut agglutinin, Ricinus communis agglutinin, and concanavalin A, bound to the surfaces of chloroplasts. Agglutination assay using human erythrocytes showed the presence of lectins specific for the above sugars in the algal vacuolar sap. A fluorescent probe 1‐(4‐trimethylammoniumphenyl)‐6‐phenyl‐a, 3,5‐hexatriene revealed that the envelope initially surrounding protoplasts was not a lipid‐based cell membrane. However, this developed several hours later. Simultaneous fluorescein diacetate and propidium iodide staining showed that the primary envelope had some characteristics of cell membranes, such as semipermeability and selective transport of materials. Also, fluorescein diacetate staining showed esterase activity in the protoplast and relocation of cell organelles and compartmentalization of cytoplasm during the process of regeneration. Both pH 7–9 and salinity 400–500 mM were found to be essentially important for the development of the protoplast envelope. When the basic regeneration process was accomplished, two alternative pathways of development were seen; about 70% of one‐celled protoplasts transformed into reproductive cells within 2 weeks after wounding, whereas others began cell division and grew into typical Microdictyon thalli. Quadriflagellate swarmers were liberated from the reproductive cells, and they germinated into mature individuals. It is therefore suggested that this species may use the wound response as a method of propagation and dispersal.
FRESHWATER DIATOMS FROM THE CANADIAN ARCTIC TREELINE AND DEVELOPMENT OF PALEOLIMNOLOGICAL INFERENCE MODELS1
Authors: Rühland Kathleen M. , Smol John P.
Published: March 2003

Relationships between surface sediment diatom assemblages and measured environmental variables from 77 lakes in the central Canadian arctic treeline region were examined using multivariate statistical methods. Lakes were distributed across the arctic treeline from boreal forest to arctic tundra ecozones, along steep climatic and environmental gradients. Forward selection in canonical correspondence analysis determined that dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), total nitrogen (TN), lake surface area, silica, lake‐water depth, and iron explained significant portions of diatom species variation. Weighted‐averaging (WA) regression and calibration techniques were used to develop inference models for DIC, DOC, and TN from the estimated optima of the diatom taxa to these environmental variables. Simple WA models with classical deshrinking produced models with the strongest predictive abilities for all three variables based on the bootstrapped root mean squared errors of prediction (RMSEP). WA partial least squares showed little improvement over the simpler WA models as judged by the jackknifed RMSEP. These models suggest that it is possible to infer trends in DIC, DOC, and TN from fossil diatom assemblages from suitably chosen lakes in the central Canadian arctic treeline region.
POLYAMINES INFLUENCE MATURATION IN REPRODUCTIVE STRUCTURES OF GRACILARIA CORNEA (GRACILARIALES, RHODOPHYTA)1
Authors: Guzmán‐Urióstegui Alberto , García‐Jiménez Pilar , Marián Fernando , Robledo Daniel , Robaina Rafael
Published: March 2003

Naturally occurring levels of putrescine, spermidine, and spermine were analyzed in female gametophyte (nonfertilized) and reproductive tissues (cystocarps) at two different stages of development in the marine red algae Gracilaria cornea J. Agardh. Endogenous polyamine levels changed at differential stages of cystocarp maturation. Highest polyamine values were found on tissue from the early post‐fertilization stage, decreasing as the cystocarp matured. Incubation experiments revealed that exogenous polyamines induced cystocarp maturation and promoted carpospore liberation, developing cell masses within 4 to 7 days in treatments with spermine. This is the first report on the effect of polyamines on cystocarp maturation in marine algae.
ACETATE IS A CHEMOATTRACTANT FOR THE COLONIAL GREEN ALGA ASTREPHOMENE GUBERNACULIFERA (CHLOROPHYCEAE)1
Authors: Hoops Harold J. , Cocina Amy E. , Binder David S. , Widjaja Armand
Published: March 2003

Astrephomene gubernaculifera Pocock is capable of growth on sodium acetate, even in the absence of light. From an evolutionary standpoint, it would be beneficial for this motile heterotrophic organism to be able to sense and swim to such an energy source. We used three assays to test for chemoattraction of A. gubernaculifera. In each case, there was strong chemoattraction to acetate. Propionate, a molecule structurally similar to acetate, also elicited a strong chemoattraction response, even though it was incapable of supporting growth in the dark in this strain. This implies that chemoattraction in A. gubernaculifera is based on a receptor‐mediated signaling response. Video analysis of colonies exhibiting the attraction response indicated that most of them remained motile in the vicinity of the acetate. This rules out the simplest possible model for accumulation in which colonies stop when they encounter increased acetate concentrations. We also tested a variety of other organic molecules for their ability to chemoattract A. gubernaculifera. Of the 11 sugars, 18 amino acids, and three other organic molecules tested, only the amino acid phenylalanine elicited chemoattraction.
CONCEPTACLE STRUCTURE OF THE PARASITIC CORALLINE RED ALGA CHOREONEMA THURETII (CORALLINALES) AND ITS TAXONOMIC IMPLICATIONS1
Authors: Broadwater Sharon T. , Harvey Adele S. , Lapointe Elizabeth A. , Woelkerling William J.
Published: March 2003

The major diagnostic features for erecting the red algal subfamily Choreonematoideae (Corallinales) were a combination of 1) absence of both cell fusions and secondary pit connections, 2) conceptacle roof and wall comprised of a single cell layer, and 3) presence of tetrasporangial pore plugs within a uniporate conceptacle in the monotypic taxon Choreonema thuretii (Bornet) Schmitz. Because this alga is a parasite, the absence of secondary cell connections is most likely an adaptation to a reduced thallus. This study shows that all conceptacles are not composed of a file of cells but rather a single layer of epithallial cells that are underlain by a thick layer of calcified acellular material; both epithallial cells and the calcified layer are produced by peripheral sterile cells. Although the outermost tetrasporangial pore canal is uniporate, there is a calcified acellular multiporate plate recessed just below the rim. The plate is produced by interspersed sterile cells and is continuous with the calcified layer supporting the conceptacle. These unique structures are likely due to parasitism rather than to the ancestral state. Based on these results and a reexamination of published micrographs depicting lenticular cells in Austrolithon intumescens Harvey et Woelkerling, we propose that both subfamily Choreonematoideae and Austrolithoideae are closely allied with subfamily Melobesioideae. This distant relationship to its host (Corallinoideae) plus a combination of unique conceptacle and unusual type of parasitism indicates that C. thuretii is an alloparasite and that it is likely the most ancient red algal parasite studied to date.
MOLECULAR PHYLOGENY OF THE GENUSCAULERPA(CAULERPALES, CHLOROPHYTA) INFERRED FROM CHLOROPLASTtufA GENE1
Authors: Famà Patrizia , Wysor Brian , Kooistra Wiebe H. C. F. , Zuccarello Giuseppe C.
Published: March 2003

The genusCaulerpaconsists of about 75 species of tropical to subtropical siphonous green algae. To better understand the evolutionary history of the genus, a molecular phylogeny was inferred from chloroplasttufA sequences of 23 taxa. A sequence ofCaulerpella ambiguawas included as a potential outgroup. Results reveal that the latter taxon is, indeed, sister to all ingroup sequences.Caulerpaitself consists of a series of relatively ancient and species‐poor lineages and a relatively modern and rapidly diversifying clade, containing most of the diversity. The molecular phylogeny conflicts with the intrageneric sectional classification based on morphological characters and an evolutionary scheme based on chloroplast ultrastructure. High bootstrap values support monophyly ofC. mexicana,C. sertularioides,C. taxifolia,C. webbiana, andC. prolifera, whereas most otherCaulerpaspecies show para‐ or polyphyly.
EFFECTS OF SMALL‐SCALE TURBULENCE ON NET GROWTH RATE AND SIZE OF TEN SPECIES OF MARINE DINOFLAGELLATES1
Authors: Sullivan James M. , Swift Elijah
Published: March 2003

Field observations and results from previous laboratory studies on the effects of turbulence on dinoflagellates have led to a paradigm in phytoplankton ecology that dinoflagellate growth is negatively affected by turbulence. To test the paradigm, 10 species of autotrophic dinoflagellates were exposed to quantified three‐dimensional turbulence generated by vertically oscillating cylindrical rods in 20‐L rectangular culture tanks. Turbulence was quantified in the tanks (as the turbulent energy dissipation rate,ε) using an acoustic Doppler velocimeter. Dinoflagellates were exposed to two turbulence treatments: high turbulence (ε∼ 10−4m2·s−3), low turbulence (ε∼ 10−8m2·s−3), and an unstirred control. In accord with the paradigm,Ceratium fusus(Ehrenberg) Dujardin had lower net growth rates in high turbulence, whereasPyrocystis noctilucaMurray ex Haeckel andCeratium tripos(O. F. Müller) Nitzsch did not increase their numbers in high turbulence. However,Alexandrium tamarense(Lebour) Balech,Pyrocystis fusiformisWyville‐Thomson ex Murray,Alexandrium catenella(Whedon and Kofoid) Balech, and aGyrodiniumsp. Kofoid and Swezy were apparently unaffected by turbulence and had the same net growth rates across all turbulence treatments. Contradicting the paradigm,Lingulodinium polyedrum(Stein) Dodge (=Gonyaulax polyedra),Gymnodinium catenatumGraham, andAlexandrium fundyenseBalech had increased net growth rates in high turbulence treatments. Cross‐sectional area (CSA) varied little across turbulence treatments for 8 of 10 dinoflagellate species tested, CSA inC. fususincreased when net growth rate decreased in high turbulence, and, conversely, CSA decreased inL. polyedrumwhen net growth rate increased in high turbulence.
Accumulation of Triacylglycerols in Haematococcus Pluvialis is Correlated with that of Astaxanthin Esters
Authors: Zhekisheva M. , Boussiba S. , Khozin‐Goldberg I. , Zarka A. , Cohen Z.
Published: March 2003

The chlorophyte Haematococcus pluvialis accumulates large quantities of astaxanthin under stress conditions. Under either nitrogen starvation or high light, the proportion of each picogram of astaxanthin was accompanied by that of 5 or 3–4 pg of fatty acids, respectively. In both cases, the newly formed fatty acids, consisted mostly of oleic (up to 34% of fatty acids in comparison to 13% in the control), palmitic and linoleic acids, were deposited mostly in triacylglycerols. Furthermore, the enhanced production of oleic acid was linearly correlated with that of astaxanthin. Astaxanthin which is mostly monoesterified, is deposited in globules made of triacylglycerols. We suggest that the production of tailor‐made oleic acid‐rich triacylglycerols on the one hand and the esterification of astaxanthin on the other hand, enable the oil globules to maintain the high content of astaxanthin esters.