bluuebunny/crossref_metadata_2025 huggingface dataset:
Oncostatin M (oncM) Spontaneous Production By Peripheral Blood Mononuclear Cells (PBMC) Is Increased In Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
Authors: De Luca G , Capasso M , Iarlori C , Paganelli R , Gambi D , Uncini A , Lugaresi A.
Published: March 2003

Pro‐inflammatory cytokines provide key signals necessary for antigen stimulation of T‐cells, inflammatory cell recruitment in the nerve, activation of cell‐mediated effector mechanisms and directly alter neuroglial and neuronal cell survival and function. The involvement of oncM, a novel pleiotropic pro‐inflammatory cytokine acting on cells of neural, vascular, hematopoietic and lymphoid origin, has not been investigated, to our knowledge, in CIDP. We have assessed oncM production by PBMC in 9 CIDP pts (5 M, 4 F; mean age: 64.4, range: 35–80), compared to 6 healthy controls (2 M, 4 F; mean age: 42.0, range: 31–54). We found that although mean spontaneous production of oncM in 72‐hr PBMC cultures was not significantly different in CIDP compared to HC (HC 251.7 ± 34.5 pg/ml vs CIDP 331.5 ± 67.4 pg/ml; 2‐tailed Student's t‐test, p = 0.08), PBMC from active pts produced higher levels of oncM. Our results, although based on very small numbers, suggest that PBMC from CIDP patients spontaneously produce high levels of oncM during the active phases (relapse or progression). The evidence that CIDP PBMC are primed in vivo to produce and release high levels of inflammatory cytokines, such as oncM suggests the presence of a basal activation of the immune system which in turn may play an important role in the physiopathology of the disease. In addition to enhancing immune‐mediated inflammatory processes, oncM might directly exert damaging effects on the blood‐nerve barrier and on neural cell survival as well as on PNS plasticity, similar to what is hypothesized in multiple sclerosis. Thus, the increased production of oncM by immune cells may play a role in maintaining the complex circuitry of molecular and cellular interactions responsible of neurologic damage in CIDP.
HCV‐RNA In Sural Nerve From Hcv Infected Patients With Peripheral Neuropathy
Authors: De Martino L , Sampaolo S , Migliaresi S , Ambrosone L , Tucci C , Nigro V , Di Iorio G.
Published: March 2003

Objective: Evaluation of hepatitis C virus (HCV) by reverse transcription‐polymerase chain reaction (RT‐PCR) in peripheral nerve tissues from HCV infected patients with peripheral neuropathy. METHODS: RT‐PCR was performed on homogenates of nerve biopsies from 17 consecutive HCV‐positive patients with peripheral neuropathy, with or without mixed cryoglobulinemia, hospitalised from 1996 to 2000. Sural nerve specimens were frozen in iso‐pentane pre‐cooled in liquid nitrogen and stored at −80°C until use. RNA was extracted from ten 7‐μm thick cryostatic sections or from a nerve trunk specimen of about 3 mm length, collected from each biopsy. Three different protocols of RNA extraction were tested (1–3). Complementary DNAs (cDNAs) were obtained without or with RNasin (Promega, Madison, WI) addition in the reaction mixture to inhibit residual RNase activity. Two sets of commercially available PCR primers for the outer and the nested reaction were used. PCR products were analysed by agarose gel electrophoresis and ethidium bromide staining. Serum samples and liver specimens from proven HCV positive patients served as positive controls, whereas sera from healthy subjects were negative controls. RESULTS: Sufficient amount of RNA could be obtained either by cryostatic sections or by in toto nerve specimens. Extraction by Trizol (Gibco‐BRL) allowed the best concentration and purity of RNA as assessed by biophotometry. The presence of RNasin didn't improve the cDNA synthesis. The resulting amplification product of the nested PCR was 187 bp long. We have always observed this product in our positive controls and never in the negative. Six samples from patients either with or without cryoglobulinemia resulted positive; 7 were negative. Four samples gave variable results. CONCLUSIONS: While 40% of the nerves in our series were undoubtedly HCV positive, the cause(s) of negative and variable results in the remaining samples is likely more complex than variations in the detection protocols and deserve further investigations. REFERENCES: 1) Chomczynski P, Sacchi N (1987). Anal Biochem 162:156. 2) Marquardt O et al. (1996). Med Microbiol Lett 5:55. 3) Chomczynski P (1993). Bio/Techniques 15:532.
Morphological And Electrophysiological Signs Of Dysmyelination In Transgenic Mice Expressing CMT1B (MPZ  DELSer34) or DSS (MPZ  Ser34Cys) Mutations
Authors: Wrabetz L , D'Antonio M , Quattrini A , Dati G , Fratta P , Fasolini M , Zielasek J , Toyka K , Messing A , Feltri ML.
Published: March 2003

Charcot‐Marie‐Tooth 1B neuropathy (CMT1B), Déjèrine‐Sottas syndrome (DSS) and Congenital Hypomyelination are each associated with mutations in MPZ, encoding P0 glycoprotein, the major structural protein of peripheral nerve myelin. To explore whether new abnormal functions of mutant MPZ can explain this phenotypic diversity, we expressed either of two MPZ mutations: DELSer34 (causing CMT1B) or Ser34Cys (causing DSS) in addition to the two normal endogeneous copies of Mpz in transgenic mice. We have shown previously that overexpression of wild type Mpz causes dose‐dependent dysmyelination. However, multiple lines of mice containing the MPZ mutants showed not only hypomyelination, but also abnormalities in myelin sheaths and onion bulbs that were never observed in Mpz overexpressor mice. To create a mouse model of CMT1B with no Mpz overexpression, one line of DELSer34 that expresses mutant Mpz at levels similar to one wildtype Mpz allele was crossed with heterozygous Mpz knock‐out mice, to obtain the genotype Mpzwt/−/MpzDELSer34. These mice manifest progressive peripheral neuropathy with hypomyelination, and onion bulbs that appear around 6 months of age. As a first step towards longitudinal studies of phenotype, we performed detailed neurophysiological analyses at 12 months of age. We found signs of demyelination, with statistically significant increases of both motor latency after proximal stimulation and F‐wave latencies, and decreases in both motor and mixed afferent nerve conduction velocities of sciatic nerve. The motor response was polyphasic and there was a trend towards reduced CMAP amplitudes. Thus, the clinical onset and progression, pathological features and neurophysiological findings provide a reasonable model of CMT1B. Longitudinal studies to correlate the onset and progression of morphological and electrophysiological abnormalities in these mice are ongoing.
Osteopontin, A Novel Schwann Cell Molecule Regulated By Axonal Contact
Authors: Bussini S , Jander S , Scarpini E , Stoll G.
Published: March 2003

Osteopontin (OPN) is a secreted phosphoglycoprotein, which interacts with the integrin on the cell surface. OPN was found originally in bone matrix and subsequently in kidney, placenta, blood vessels, adult rat brain and in a number of cell lines in response to inflammatory cytokines and growth factors. An elevated expression of OPN has been identified in a number of disease processes, including autoimmune disorders, and in a number of inflammatory reactions in peripheral organs with spatial and temporal association to macrophage migration and accumulation. Functionally, OPN has been implicated in cell attachment and chemotaxis, suggesting a functional role of the newly deposited matrix protein in cell‐matrix interactions and remodelling. The aim of the present study was to investigate the distribution of osteopontin within the PNS, and in particular, 1) to determine the expression of osteopontin in rat Schwann cells cultured “in vitro,” 2) to define “in vivo” the spatial and temporal expression of osteopontin in the rat peripheral nerve in normal conditions and after crush injury, and 3) to study “in vivo” the possible correlation between OPN and neurofilament expression in human nerve biopsies from neuropathies of different origin. The results show that OPN is constitutively expressed in the PNS at the level of the Schwann cell. During Wallerian degeneration, only a transient increase of OPN mRNA was observed during the first 4 days after sciatic nerve crush. Similarly, OPN was expressed in Schwann cells in sural nerve biopsies which lack significant pathology. In chronic axonal polyneuropathy, as assessed by a decrease of neurofilament expression, OPN was dramatically reduced. In conclusion, these findings identify OPN as a novel Schwann cell antigen regulated by axonal contact. In contrast to other tissues, such as injured skin, ischemic heart and brain, where infiltrating macrophages express high levels of OPN during wound healing, OPN during Wallerian degeneration of the PNS appears to be downregulated.
Chronic Progressive Inflammatory Demyelinating Polyneuropathy In Childhood: Clinical And Electrophysiological Features
Authors: Capasso M , Uncini A.
Published: March 2003

Chronic inflammatory demyelinating neuropathy (CIDP) occurring in childhood is rare and the diagnosis in indolently progressive cases may be difficult. We report 7 children (age 8–12 years) with insidiously progressive weakness and atrophy (in 3 cases) predominantly involving the lower limbs and mimicking a genetically determined neuropathy. Family history was negative in all cases. Numbness and paresthesias were present in 1/7 and mild sensory signs in 3/7 patients. Motor conductions were slowed in at least two nerves in 6/7, distal motor latencies prolonged in 4/7 and F waves delayed in 6/7 children, but these findings, although characteristic of a demyelinating neuropathy, did not help in the differential diagnosis with an inherited disorder. The following features documenting focal and non‐uniform nerve conduction abnormalities indicated an acquired demyelinating disorder: 1) abnormal terminal latency index in at least one nerve in 5/7 children, 2) conduction block (reduction of proximal CMAP area> 50%) in at least one nerve in 5/7 children, 3)> 10 m/s conduction velocity difference among nerves of upper limbs or nerves of lower limbs in 4/7 children, 4) abnormal median sensory in presence of normal sural sensory conduction in 3/7 children. CSF protein concentration was increased in 5/7 (59–120 mg/dl). One patient had a self‐limited course and recovered spontaneously in 10 months. Three children had a monophasic course, improved with steroids and had little or no residual disability. The remaining three with the longest disease duration before diagnosis (>2 years) improved with steroids but showed some residual distal weakness and atrophy and two developed foot deformities. Three children had at least one relapse at steroid tapering or discontinuation. Because of therapeutic implication the possibility of a CIDP occurring in childhood should always be kept in mind. An extensive electrophysiological study searching for indicators of non‐uniform nerve conduction abnormalities may suggest the diagnosis in most cases. When the diagnosis is doubtful and genetic studies are negative we recommend a therapeutic trial of steroids for at least four weeks.
Identification Of Two New Pmp22 Mouse Mutants Using Large‐Scale Mutagenesis And A Novel Rapid Mapping Strategy
Authors: Isaacs AM , Davies KE , Hunter AJ , Nolan PM , Vizor L , Peters J , Gale DG , Kelsell Dp , Latham ID , Chase JM , Fisher EMC , Bouzyk MM , Potter A , Masih M , Walsh FS , Sims MA , Doncaster KE , Parsons CA , Martin J , Brown SDM , Rastan S , Spurr NK , Gray IC
Published: March 2003

Mouse mutants have a key role in discerning mammalian gene function and modelling human disease; however, at present mutants exist for only 1–2% of all mouse genes. In order to address this phenotype gap, we have embarked on a genome‐wide, phenotype‐driven, large‐scale N‐ethyl‐N‐nitrosourea (ENU) mutagenesis screen for dominant mutations of clinical and pharmacological interest in the mouse. Here we describe the identification of two similar neurological phenotypes and determination of the underlying mutations using a novel rapid mapping strategy incorporating speed back‐crosses and high throughput genotyping. Two mutant mice were identified with marked resting tremor and further characterized using the SHIRPA behavioural and functional assessment protocol. Back‐cross animals were generated using in vitro fertilization and genome scans performed utilizing DNA pools derived from multiple mutant mice. Both mutants were mapped to a region on chromosome 11 containing the peripheral myelin protein 22 gene (Pmp22). Sequence analysis revealed novel point mutations in Pmp22 in both lines. The first mutation, H12R, alters the same amino acid as in the severe human peripheral neuropathy Dejerine Sottas syndrome and Y153TER in the other mutant truncates the Pmp22 protein by seven amino acids. Histological analysis of both lines revealed hypomyelination of peripheral nerves. This is the first report of the generation of a clinically relevant neurological mutant and its rapid genetic characterization from a large‐scale mutagenesis screen for dominant phenotypes in the mouse, and validates the use of large‐scale screens to generate desired clinical phenotypes in mice.
Nerve pathology in the type 1 diabetic dog: effects of treatment with sulindac
Authors: Walker David , Siddique Irfan , Anderson Heather , Gardiner Tom A. , Archer Desmond B. , Boulton Andrew J.M. , Malik Rayaz A.
Published: March 2003

Abstract  The purpose of this study was to define pathological abnormalities in the peripheral nerve of a large animal model of long‐duration type 1 diabetes and also to determine the effects of treatment with sulindac. Detailed morphometric studies were performed to define nerve fiber and endoneurial capillary pathology in 6 control dogs, 6 type 1 diabetic dogs treated with insulin, and 6 type 1 diabetic dogs treated with insulin and sulindac for 4 years. Myelinated fiber and regenerative cluster density showed a non‐significant trend toward a reduction in diabetic compared to control animals, which was prevented by treatment with sulindac. Unmyelinated fiber density did not differ among groups. However, diabetic animals showed a non‐significant trend toward an increase in axon diameter (p < 0.07), with a shift of the size frequency distribution towards larger axons, which was not prevented by treatment with sulindac. Endoneurial capillary density and luminal area showed a non‐significant trend toward an increase in diabetic animals, which was prevented with sulindac treatment. Endoneurial capillary basement membrane area was significantly increased (p < 0.05) in diabetic animals, but was not prevented with sulindac treatment. We conclude that the type 1 diabetic dog demonstrates minor structural abnormalities in the nerve fibers and endoneurial capillaries of the sciatic nerve, and treatment with sulindac ameliorates some but not all of these abnormalities.
Peripheral neuropathy associated with mitochondrial disorders: 8 cases and review of the literature
Authors: Bouillot S. , Martin‐Négrier M.L. , Vital A. , Ferrer X. , Lagueny A. , Vincent D. , Coquet M. , Orgogozo J.M. , Bloch B. , Vital C.
Published: March 2003

Abstract  Forty‐three cases of peripheral neuropathy (PN) have been reported in the literature with a proven mitochondria (mt) DNA mutation, and 21 had a peripheral nerve biopsy (PNB). We studied 8 patients, 1 of whom had severe sensory PN, 3 mild PN, and 4 subclinical PN. Nerve biopsy was performed in every case; all patients showed axonal degeneration and 4 showed features of primary myelin damage. In addition, there were 2 crystalline‐like inclusions in the Schwann cell cytoplasm of a patient with MERRF, and 1 in a patient with multiple deletions on the mtDNA. There are 11 cases of PNB in the literature with axonal lesions, 5 with demyelination, and 4 with mixed lesions. One PNB was not modified. A few crystalline‐like inclusions were seen in 1 case of MERRF. Such inclusions were first reported in the Schwann cell cytoplasm of unmyelinated fibers in a patient with Refsum disease and were considered to be modified mitochondria. However, their mitochondrial origin remains debatable.
Repair of ventral root avulsions of the brachial plexus: a review
Authors: Holtzer Carlo A.J. , Marani Enrico , Lakke Egbert A.J.F. , Thomeer Ralph T.W.M.
Published: March 2003

Abstract  Traumatic root avulsions of the brachial plexus constitute a devastating lesion resulting in loss of function of the upper limb and carry a large emotional and socioeconomic impact. In this literature survey, the different factors involved in root avulsion are discussed in combination with various surgical techniques for repair of experimental ventral root avulsion. Until now repair of root avulsions did not generate unequivocal proof of recovery of limb function, particularly of the hand. More experimental studies are needed to assess the efficacy of several repair techniques, the optimal timing for surgery, and the complications associated with spinal cord manipulation.
PARAPROTEINEMIC NEUROPATHIES
Authors: Vital A.
Published: March 2003

The occurrence of a peripheral neuropathy (PN) in association with a monoclonal gammopathy is quite common and suggests that monoclonal proteins may play a pathogenetic role in peripheral nervous system damage. In fact, paraproteinemic PN constitute an heterogeneous group of disorders related to various pathogenetic factors, and the histopathologic features in peripheral nerve biopsies differ from one condition to another. In several well defined disorders, the responsibility of the monoclonal component in the development of the PN has been evidenced. This is the case for most of the PN associated with an IgM monoclonal gammopathy, either a monoclonal gammopathy of undetermined significance (MGUS) or Waldenstrom's macroglobulinemia. The responsibility of the monoclonal protein in the occurrence of amyloid neuropathy related to multiple myeloma is also recognized. However, most IgG or IgA MGUS, as well as the monoclonal component in POEMS syndrome, have an uncertain causal relationship with the neuropathy. PN associated with monoclonal cryoglobulin (type 1) are occasional and differ from those associated with mixed cryoglobulins (types 2 or 3).
EFFECTS OF IRON AND LIGHT STRESS ON THE BIOCHEMICAL COMPOSITION OF ANTARCTIC PHAEOCYSTIS SP. (PRYMNESIOPHYCEAE). I. INTRACELLULAR DMSP CONCENTRATIONS
Authors: Stefels Jacqueline , van Leeuwe Maria A.
Published: March 2003

Iron is essential for phytoplankton growth, as it is involved in many metabolic processes. It controls photosynthesis as well as many enzymatic processes. As such, iron affects the cell’s energy supply and contributes to the assimilation of carbon and nitrogen. To determine whether iron limitation would result in energy stress or induced nitrogen deficiency, an Antarctic Phaeocystis sp. (Prymnesiophyceae) strain was studied for its biochemical composition, with the main emphasis on intracellular production of dimethylsulfoniopropionate (DMSP). DMSP is suggested to replace nitrogen containing solutes under conditions of nitrogen deficiency. Batch cultures of Antarctic Phaeocystis sp. were grown under iron‐rich and iron‐poor conditions and simultaneously subjected to high and low light intensities. Iron depletion induced chlorosis and suppressed growth rates as well as the maximum yield of the cultures; these effects were reinforced by low light intensities. Cell volumes were strongly reduced under iron‐limited conditions. However, this reduction in cell volume was accompanied by a reduced DMSP content only in cultures experiencing low light intensities. Under high light conditions, no reduction of DMSP was observed; hence, intracellular DMSP concentrations increased. These observations are discussed relative to carbon and nitrogen metabolism and the biosynthetic pathway of DMSP. It is argued that under high light, low iron conditions, the cells were bordering on nitrogen deficiency induced by iron limitation, whereas under low light, low iron conditions, the cells were energy limited resulting in overall suppressed metabolic rates. Between treatments, DMSP to chlorophyll‐a ratios varied by a factor of 5, demonstrating the dependence of this parameter on the physiological state of the cell.
EXTRACELLULAR POLYSACCHARIDES FROM ANKISTRODESMUS DENSUS (CHLOROPHYCEAE)
Authors: Paulsen Berit Smestad , Aslaksen Torun , Freire‐Nordi Cristina S. , Vieira Armando A. H.
Published: March 2003

The dissolved extracellular compounds produced by the Chlorococcalean Ankistrodesmus densus Kors. were investigated for their molecular masses and chemical composition. Gel permeation chromatography showed apparent relative molecular masses of 2 × 106 and 104, respectively, for two distinct fractions, termed A and B. The higher molecular weight fraction (A) contained mainly fucose and 3‐O‐methylgalactose, whereas galactose, glucose, mannose, and rhamnose were present in smaller amounts. Methylation analyses showed that the main structural features are fucose as a highly branched part of polymer A with substitutions in both position 2 and position 4, the substitutions on one of those positions being primarily terminal 3‐O‐methylgalactose and the other one involved as the linkage of the main chain of the polymer. Because of the presence of both fucose and 3‐O‐methylgalactose, this polymer is highly hydrophobic. In fraction B, mannose represented more than 60% of the carbohydrate material present, whereas the remaining part contained rhamnose, fucose, xylose, and glucose in almost equal amounts. 3‐O‐methylgalactose and galactose were present as minor elements. Fraction B is basically a mannose‐containing polymer in which the mannose units are either 1→4 or 1→2 linked. Traces of glucuronic acid and protein were present in both fractions; neither sulfate nor phosphate was detected.
PROTEINS IMMUNOLOGICALLY RELATED TO DEHYDRINS IN FUCOID ALGAE
Authors: Li Rui , Brawley Susan H. , Close Timothy J.
Published: March 2003

Adult fucoid algae on Atlantic shores have well‐characterized, species‐specific tolerances to the varying levels of desiccation that occur from the low to high intertidal zones; however, less is known about embryonic tolerances and their mechanistic basis. We investigated this by 1) exposing embryos of Fucus evanescens C. Agardh, F. spiralis L., and F. vesiculosus L. from the Maine shore to osmotic desiccation in hypersaline seawater and 2) examining whether these embryos contain species‐specific dehydrins, proteins first identified in higher plants that are hypothesized to confer tolerance to dehydration. Embryonic survival when cultured in hypersaline seawater >100 practical salinity units (psu) correlated with the position of these species in the intertidal zone (F. spiralis > F. vesiculosus > F. evanescens), but all 1‐day‐old embryos of these species tolerated treatment with 100 psu or lower seawater. Proteins (17–105 kDa) immunologically related to dehydrins were detected on western blots with dehydrin antibodies raised against a synthetic peptide representing the conserved motif of dehydrins in higher plants. These proteins were constitutive and unstable when subjected to prolonged (>15 min) temperatures above 55° C, unlike most higher plant dehydrins, which are inducible and remain soluble at 75°–100° C. The presence of these proteins was species‐ and stage‐specific. Sperm of F. vesiculosus had a characteristic protein of 76 kDa, whereas eggs and embryos (6 h to 3 days old) had a 92‐kDa protein. By 1 week of age, expression of the 92‐kDa protein decreased, and the 35‐kDa protein of adults was present. Embryos of A. nodosum L. and Pelvetia compressa J. Agardh DeToni contained an 85‐kDa protein rather than the 92‐kDa protein of Fucus embryos (F. distichus L., F. evanescens, F. spiralis, and F. vesiculosus). The 92‐kDa protein became more abundant in embryos exposed to hyperosmotic seawater at 50 psu (F. evanescens and F. vesiculosus) or 150 psu (F. spiralis); however, dehydrin‐like proteins of some molecular masses decreased in abundance simultaneously. Further characterization of these proteins is required to establish whether they protect embryos against intertidal desiccation.
MEDITERRANEAN CAULERPA TAXIFOLIA AND C. MEXICANA (CHLOROPHYTA) ARE NOT CONSPECIFIC
Authors: Olsen Jeanine L. , Valero Myriam , Meusnier Isabelle , Boele‐Bos Stella , Stam Wytze T.
Published: March 2003

In 1984, Caulerpa taxifolia (Vahl) C. Agardh was reported along the coast of Monaco. Over the past decade it has spread along 60 km of the Mediterranean coastline and presently represents a potential risk to biodiversity. Several explanations have been advanced regarding the presence of C. taxifolia in the Mediterranean. One hypothesis maintains that the alga was introduced accidentally into the sea at Monaco, where it has been used as a decorative alga in aquaria. Caulerpa taxifolia has not been reported in earlier marine floras of the Mediterranean, and its sudden appearance has suggested that it may be a recent introduction. Another hypothesis proposes that C. taxifolia and Caulerpa mexicana Sonder ex Kützing are morphological variants of one another and hence conspecific taxa. Caulerpa mexicana has been found in the eastern Mediterranean since at least 1941. In order to establish the taxonomic identities of these taxa, individuals from five populations of C. taxifolia and four populations of C. mexicana were collected from within and outside of the Mediterranean. Comparative DNA sequence analysis of the nuclear ribosomal cistron, including the 3′‐end of the 18S, ITS1, 5.8S, and ITS2 regions, show clear phylogenetic separation of the two taxa using parsimony and maximum likelihood analyses. Separation is maintained whether the analyses are based on just the more conserved 18S data or just the fast‐ evolving spacers. The two species are thus not conspecific. For specimens of uncertain identity (i.e. taxifolia–mexicana intermediates), a PCR diagnostic amplification can easily be performed because the ITS1 in C. taxifolia is 36 nucleotides shorter than the ITS1 in C. mexicana. Whether or not C. taxifolia has been present for a longer period of time in the marine flora, either as a cryptic endemic species or as the result of one or more introductions, represents an additional hypothesis that will require identification of biogeographic populations from throughout the world, as well as a population‐level study of the Mediterranean region.
ULTRAVIOLET ABSORBING SUBSTANCES FROM AGARUM FIMBRIATUM (PHAEOPHYCEAE) PROTECT GRIFFITHSIA PACIFICA FROM UV RADIATION
Authors: Kim K.Y. , Garbary D.J. , Hoffmann J. , Duggins D.
Published: March 2003

We examined whether naturally occurring polyphenols produced by a brown alga can protect other organisms from ultraviolet radiation. Fragments of Griffithsia pacifica were grown in medium supplemented with a seawater extract of Agarum fimbriatum (3% w/v in seawater for 2 h). Cultures were exposed to cool‐white fluorescent light (7–7.5 μMol photons cm−2 s−1) in the presence or absence of 130 to 168 μW cm−2 UV‐A and 85 to 112 μW cm−2 UV‐B. Regenerating fragments were scored for five qualitative or quantitative measures of growth. Rhizoid growth was not inhibited by the polyphenol extract after ten days. UV radiation in the absence of polyphenols caused considerable cell death and slower growth. Thus, the presence of polyphenols provided protection from UV radiation such that in the highest concentration of polyphenols (1:1 medium:extract), rhizoid growth in UV exposed fragments was approximately 60% as great as control plants without both polyphenols and UV radiation. Plants exposed to UV radiation in the absence of polyphenol extract showed poor rhizoid regeneration and extensive cell death. These experiments document the nature of UV‐A and UV‐B damage to growing red algae, and provide strong evidence that polyphenols from brown algae may have a role in protecting subtidal, benthic algal communities from UV radiation.
NITROGEN ASSIMILATION AND ALLOCATION STRATEGIES OF POLAR SEAWEEDS FROM DIFFERING NUTRIENT ENVIRONMENTS
Authors: Korb R.E. , Gerard V.A.
Published: March 2003

Nitrogen assimilation and allocation strategies were compared in polar macroalgae from environments with similar near‐freezing temperatures and low annual irradiance but differing dissolved inorganic nitrogen (DIN) regimes. The antarctic endemic, Himantothallus grandifolius, experiences high nitrate concentrations year‐round and occasionally high, but variable, ammonium levels. H. grandifolius cannot store nitrogen or maintain growth under periods of low N‐supply. The arctic endemic, Laminaria solidungula, is exposed to seasonal fluctuations in DIN, with N‐limitation occurring during the summer. L. solidungula showed “storage‐specialist” characteristics of nitrate uptake, with high Vmax allowing this species to take advantage of seasonally elevated nitrate concentrations to accumulate large organic and inorganic N‐reserves. H. grandifolius had a high Vmax for ammonium, allowing the alga to utilize pulses of this nutrient. In the presence of both DIN forms, nitrate uptake was significantly reduced in both species. Furthermore, H. grandifolius and L. solidungula demonstrated significantly reduced uptake and assimilation of nitrate during short‐term and prolonged periods of darkness, while ammonium uptake and assimilation were relatively unaffected by light. Although preferential uptake of ammonium, particularly in the dark, allows both species to conserve energy in their cold, low‐light environments, the antarctic species, which does not have the additional problem of N‐limitation, showed stronger energy conserving traits. Nitrogen assimilation characteristics of the arctic species appeared to balance energy conservation with the need to minimize N‐limitation in an environment that alternates between low light and low N availability.
PATTERNS AND CONSEQUENCES OF SPORE DISPERSAL IN THE GIANT KELP, MACROCYSTIS PYRIFERA
Authors: Reed D.C. , Raimondi P.T. , Washburn L.
Published: March 2003

We investigated patterns of spore dispersal in the giant kelp Macrocystis pyrifera by collecting 80 independent measurements of spore dispersal from isolated individuals and isolated groups of individuals over a two‐year period. Our results indicate that giant kelp spores routinely disperse both short (i.e. a couple meters) and long (i.e. hundreds to thousands of meters) distances depending on the oceanographic conditions. One consequence of spore dispersal over short distances is self‐fertilization (i.e., fertilization between male and female gametophytes derived from the same sporophyte). Field experiments designed to test the effects of self‐fertilization on lifetime fitness in Macrocystis revealed significant inbreeding depression. Birth rates in self‐fertilized populations were ca. 50% of those produced from outcrossing, which lead to significant differences in cohort size that persisted up through the adult stage. In contrast to outcrossed populations, very few individuals produced from selfing became reproductively mature, and those that did were significantly less fecund than outcrossed individuals. By contrast, long‐range dispersal of spores leads to increased rates of outcrossing. However, long‐range dispersal is typically accompanied by massive dilution of spores, leading to low densities of spore settlement. Sparse spore settlement decreases the overall chance of fertilization in the microscopic gametophyte generation thereby reducing the potential for colonization of the macroscopic sporophyte stage. Large population size of adult sporophytes coupled with the synchronous release of spores in response to environmental cues can help offset the effects of spore dilution and extend the distances over which giant kelp is able to colonize.
BIOGEOGRAPHY OF BATRACHOSPERMUM HELMENTOSUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH AMERICA USING MOLECULAR AND MORPHOLOGICAL DATA
Authors: Vis M.L. , Miller E.J. , Hall M.M.
Published: March 2003

Twelve collections of the freshwater red alga Batrachospermum helmentosum were investigated using molecular sequence and morphological data. Collections were from streams throughout the range of this species in North America, from Louisiana and Tennessee in the south to Michigan and Massachusetts in the north. Eleven morphometric characters were measured for each of the specimens sequenced. Both the rubisco large subunit gene (rbcL) and the ribosomal DNA internal transcribed spacers (ITS1 & 2) were sequenced. Morphometic results showed individuals from the various locations to be morphologically uniform with little variation in pertinent characters. In the analysis of the rbcL data, samples from Connecticut, Ohio, Louisiana, North Carolina and Indiana were identical in sequence and the Rhode Island and Massachusetts samples were most derived. The Michigan and Tennessee samples were closely related to each other but not the other samples. For the ITS data, the tree topology was similar to that obtained with the rbcL data. In comparison with rbcL, sequence variation in the ITS region among samples was greater and showed more resolution among the stream sites. In terms of biogeography, three geographically close samples (Connecticut, Rhode Island, Massachusetts) were most closely related. However, genetic relationships did not necessarily reflect geographic distance. For example, two distant populations, Louisiana and Indiana, were most closely related. Variation in ITS sequence data among individuals from a single stream site will be discussed.
DIATOM SILICA BIOMINERALIZATION: AT NANOSCALE LEVEL A CHEMICALLY UNIFORM PROCESS
Authors: Vrieling E. G. , Gieskes W. W.C. , Beelen T. P. M. , Van Santen R.A.
Published: March 2003

Using a high‐brilliance synchrotron X‐ray source, combined small‐ and wide‐angle X‐ray scattering (SAXS and WAXS) was applied to study nanoscale characteristics, in particular pore size in the range of 3 to 65 nm, of a variety of unialgal cultures of centric and pennate diatoms, and of mixed diatom populations sampled in the field. Results of scattering analysis were compared with details of pore size, structure and orientation visible at the electron microscopic level. WAXS patterns did not reveal any crystalline phase or features of microcrystallinity (resolution 0.07 to 0.51 nm), which implies a totally amorphous character of the SiO2 matrix of the frustule material. SAXS data (resolution 3 to 65 nm) provided information on geometry, size, and distribution of pores in the silica. Overall, two pore regions were recognized that were common to the silica of all samples: the smallest (d less than 10 nm) regularly spaced and shaped spherically, the larger (up to 65 nm) being cylinders or slits. Apparently, at a nanoscale level diatomaceous silica is quite homologous among species, in agreement with the chemical principles of silica polymerization under the conditions of pH and precursor concentrations inside the silicon deposition vesicle. The final frustule “macro”‐morphology is of course species‐specific, being determined genetically. Synthetically‐derived MCM‐type silicas have a similarly organized pore distribution in an amorphous silica matrix as we found in all diatom species studied. We therefore suggest that organic molecules of a kind used as structure‐directing agents to produce these artificial silicas play a role in the nucleation of the silica polymerization reaction and the shaping of pore morphology inside the silicon deposition vesicle of diatoms. Structure‐directing molecules now await isolation from the SDV, followed by identification and characterisation by molecular techniques.
COLD ACCLIMATION OF TWO STRAINS OF THE CYANOBACTERIUM, SPIRULINA PLATENSIS
Authors: Chien L.‐F. , Vonshak A.
Published: March 2003

The changes in the antioxidant enzymes and photosynthetic activities during cold acclimation in two strains of the cyanobacterium, Spirulina platensis, marked as Kenya and M2, were investigated. Cells were cultured at 33° C then transferred to either 20° C or 15° C. Growth rate of both strains ceased when the temperature shifted from 33 to 20° C and resumed to a slower rate after the first 24 h. Similarly when the temperature was shifted from 33 to 15° C, a complete cessation of growth took place but this time the growth resumed only after 5 to 6 days. The activities of ascorbate perooxidaseperoxides were immediately decreased to about 40–60% in Kenya and 20–40% in M2 when the temperature was shifted to 20 or 15° C and remained about the same level during further cold cultivation. The activity of glutathione reductase was not modified immediately after the transfer to 20 or 15° C; however, it trended to increase gradually in M2 during cultivation at 15° C. The changes in the maximal efficiency of PSII photochemistry (Fv/Fm) were followed in order to study the effect of low temperature acclimation on the photosynthetic apparatus of the two strains.
REACTIVE OXYGEN METABOLISM IN THE TROPICAL BROWN ALGA DICTYOTA DICHOTOMA
Authors: Davison R. I. , Collén J. , Fegley J.C.
Published: March 2003

We studied reactive oxygen metabolism in natural populations of the brown alga Dictyota dichotoma growing on coral reefs on the west coast of Barbados in March 2000. Algae from deep water (27 to 30 m) had lower dark respiration (0.08 cf. 0.21 mmole O2 cm−2 h−1), light compensation point (7 cf. 18 mmole photons m−2 s−1) and gross light‐saturated photosynthesis (0.44 cf. 0.68 mmole O2 cm−2 h−1) than the same species from shallow (2 to 3 m) water. Compared to shallow water algae, those from 27 to 30 m were more susceptible to photoinhibition, produced more reactive oxygen (as measured by dichlorofluorescein production) and suffered lipid peroxidation when exposed to surface solar radiation. These data could not be explained by differences in activities of reactive oxygen processing enzymes. Although activities of ascorbate peroxidase (APX) were higher in shallow water algae, the opposite was true for superoxide dismutase (SOD) and catalase. In situ reactive oxygen production in shallow water D. dichotoma varied over the course of the day on both a sunny and overcast day, and was proportional to incident light and photosynthetic electron turnover rate (ETR) determined with a submersible modulated fluorometer. The natural population did not appear to experience lipid peroxidation. Activities of SOD and APX remained constant over the light period, whereas catalase declined in the afternoon on the sunny day, but not on the overcast day. Overall, our data demonstrate that algae produce reactive oxygen in nature under non‐stressed conditions and moderate light (< 300 mmole photons m−2 s−1) and that this occurs independently of the activity of catalase.
GRAPPLING WITH CONFLICT AMONG INFORMATION SOURCES IN RECONSTRUCTION OF THE EARLY EVOLUTION OF LAND PLANTS
Authors: Delwiche C.F. , Karol K. G. , Cimino  , McCourt R. M.
Published: March 2003

Although a close relationship between embryophytes (land plants) and charophycean green algae has been discussed for over a hundred years, the precise nature of this relationship remains uncertain. This is largely because of difficulty reconstructing the phylogeny of the basal members of this group. Recent analyses of SSU rDNA, rbcL, and concatenated chloroplast genes have all produced different phylogenies, and none is fully compatible with morphological data. Noteworthy conflict is apparent in the positions of the unicellular flagellate Mesostigma and the filamentous epiphyte Chaetosphaeridium. Several phenomena could result in such incongruence, including problems with the underlying data (taxon ID, sequence determination, alignment, etc.), choice of analytical method, lack of resolution with one or more of the datasets, unrecognized paralogy, and horizontal gene transfer. We have examined each of these possible sources of incongruence, and have determined that several factors underlie the apparent conflict among phylogenies. When these factors are taken into account a consensus molecular phylogeny begins to emerge. Despite the long divergence time in question, the prospects for reconstruction of land plant phylogeny are good.
VARIATION IN TOXIN PRODUCTION OF SYNCHRONIZED CULTURES OF CHRYSOCHROMULINA POLYLEPIS (PRYMNESIOPHYTA)
Authors: Eschbach E. , John U. , Reckermann M. , Medlin L.K.
Published: March 2003

In European coastal waters toxic blooms of Prymnesiophytes occur regularly. Chrysochromulina polylepis is a highly toxic member of this taxonomic group, which formed a devastating bloom in Scandinavian waters in 1988. Blooms like these can cause severe damage to benthic and pelagic communities and can result in million dollar losses for commercial fisheries and mariculture of fin and shellfish. Effective prevention and mitigation strategies require an understanding of environmental factors that contribute to the formation of harmful algal blooms, as well as information on the regulation of algal toxicity at the molecular level. To approach the latter aspect, we investigated the variation in toxin production of synchronized C. polylepis cultures by means of a sensitive bioassay and by flow cytometry. The results so far obtained show significant variation in cellular toxin content and specific toxin production throughout the sampling period of three days. The existence of times in the cell cycle of high and low levels of toxin production will be used as the basis for the identification of differentially expressed genes and proteins using differential display and 2‐D protein gel electrophoresis. Preliminary results concerning the molecular analysis will be presented as well.
BIODIVERSITY OF PLANKTONIC DINOFLAGELLATE SPECIES IN MANGROVE PONDS, PELICAN CAYS, BELIZE
Authors: Faust
Published: March 2003

Information on the population structure of planktonic dinoflagellates is reported in the coral reef‐mangrove ecosystem at Pelican Cays, Belize. Six sites examined included: Cat Cay, Douglas Cay, Elbow Cay, Fisherman's Cay, Lagoon Cay and Manatee Cay. A spectacular and rich dinoflagellate taxa including oceanic, coastal and offshore species are illustrated. The presence of oceanic species in the studied cays is an unexpected observation since dinolfagellate assemblages are virtually enclosed within ponds bordered by coral ridges that limits water exchange with the open ocean except during storm events. I am also reporting significant differences in the dinoflagellate associations among the studied cays. Dominant taxa included 16 Proroperidinium species, 11 Gonyaulax species, and ten Ceratium species. Only six planktonic species were harmful. Bloom forming species included Ceratium furca and Gonyaulax polygramma. A much more diverse authotrophic and heterotrophic dinoflagellate population characterizes the Pelican Cays than previously suspected. Some species are reported the first time: Protoperidinium belizeanum sp. nov., P. pyrum Balech, P. steidingerae Balech, P. depressum (Bailey) Balech, and P. divergens (Ehrenberg) Balech. These results demonstrate that the Belizean coral reef‐mangrove ecosystem is a delicate and species‐rich environment, and as such, should be protected and preserved.
GRATELOUPIA DORYPHORA HAS ESTABLISHED RESIDENCY IN RHODE ISLAND WATERS
Authors: Harlin M. M. , Villalard‐Bohnsack M.
Published: March 2003

Since 1994, when Grateloupia doryphora (Halymeniaceae, Rhodophyta) was first detected in Rhode Island, the species has spread to the northern portions of Narragansett Bay and onto the open coast of Rhode Island Sound. Specimens collected at 5 m depths off North Prudence Island reached 175 cm in length and establish this alga as the largest member of the Florideophyceae on North Atlantic shores. Percent cover of populations is seasonal: highest in fall (September through November) and lowest in spring (March through May). Monthly measurements at three stations in Narragansett Bay show significant seasonal differences (p < 0.01) over two annual cycles. Artificial substrata placed in the field at known periods allowed measurements of growth rates on individual thalli. Laboratory culture clarified the sequence of life history stages that make this species a successful contender for space.
BIOLUMINESCENCE IN THE MARINE DINOFLAGELLATE PYROCYSTIS LUNULA
Authors: Heimann K. , Matuszewski J. , Stiffey A.V. , Klerks P. L.
Published: March 2003

Marine dinoflagellates are the main contributors to a phenomenon commonly known as “phosphorescence of the sea”. Several investigators using different dinoflagellate species have shown that dinoflagellate bioluminescence is regulated by a circadian rhythm. Diverse bioluminescent systems exist in different organisms; however, all systems utilize an enzyme luciferase and the substrates luciferins, which show inter‐species cross‐reactivity. In marine dinoflagellates, luciferase and luciferin are localized in specific organelles, termed scintillons, which are usually located in close proximity to the vacuole during their active state. Bioluminescence is stimulated by mechanical stress or by acidification of the medium. Nicolas and co‐workers (1987, J. Cell Biol. 105: 723‐735) suggested that bioluminescence is triggered by an acidification of the scintillon caused by events that depolarize the tonoplast (proton trigger model). However, little is known about the signal transduction cascade that relays the mechanical stimulus perceived at the plasma membrane to the tonoplast. This study investigates the response of the bioluminescent system of Pyrocystis lunula to various parameters such as age of culture, light quality and quantity, disturbance (handling), sensitivity to chemicals, etc. to determine, if the bioluminescent response of P. lunula suitable for measuring environmental toxicants. The assay system used measures bioluminescence in response to mechanical stimuli or acidification allowing us to determine, if the response varies amongst the two different types of stimulation under different experimental conditions. The use of cell‐permeant inhibitors for certain signaling pathways in this assay may help to biochemically characterize events involved in signal transduction from the plasma membrane to the scintillon.
REPRODUCTIVE, CULTURE AND REGENERATION STUDIES OF THE EDIBLE RED ALGA CALLOPHYLLIS IN CHILE
Authors: Hernández‐González M.C. , Aroca G. , Filœn L. , Buschmann A.H.
Published: March 2003

In Chile, the demand of edible seaweeds has increased during recent years and Callophyllis variegata is one of the most demanded species. This study summarizes information on phenology, aspects, in vitro culture and vegetative propagation methods for Callophyllis. Results indicate that spore production occurs mainly during winter, and recruitment of new plants appear in nature in the spring. Culture studies indicate that spores presented higher germination and growth rates at 8° C and 10 to 12 μmol m−2 s−1. Furthermore, these results indicate that this species presents a high potential for regeneration from its holdfast. The manipulation of temperature, light and culture medium enhances the regeneration process and growth of Callophyllis in the laboratory.
FLOW CYTOMETRIC ANALYSES OF VIRAL INFECTION IN TWO MARINE PHYTOPLANKTON SPECIES, MICROMONAS PUSILLA (PRASINOPHYCEAE) AND PHAEOCYSTIS POUCHETII (PRYMNESIOPHYCEAE)
Authors: Brussaard Corina P. D. , Thyrhaug Runar , Marie Dominique , Bratbak Gunnar
Published: March 2003

Cell characteristics of two axenic marine phytoplankton species, Micromonas pusilla (Butscher) Manton et Parke and Phaeocystis pouchetii (Hariot) Lagerheim, were followed during viral infection using flow cytometry. Distinct differences between noninfected and infected cultures were detected in the forward scatter intensities for both algal species. Changes in side scatter signals on viral infection were found only for P. pouchetii. Chlorophyll red fluorescence intensity per cell decreased gradually over time in the infected cultures. DNA analyses were performed using the nucleic acid–specific fluorescent dye SYBR Green I. Shortly after infection the fraction of algal cells with more than one genome equivalent increased for both species because of the replication of viral DNA in the infected cells. Over time, a population of algal cells with low red autofluorescence and low DNA fluorescence developed, likely representing algal cells just prior to viral lysis. The present study provides insight into basic virus–algal host cell interactions. It shows that flow cytometry can be a useful tool to discriminate between virus infected and noninfected phytoplankton cells.