bluuebunny/crossref_metadata_2025 huggingface dataset:
The model legume Medicago truncatula A17 is poorly matched for N2 fixation with the sequenced microsymbiont Sinorhizobium meliloti 1021
Authors: Terpolilli Jason J. , O’Hara Graham W. , Tiwari Ravi P. , Dilworth Michael J. , Howieson John G.
Published: April 2008

DOI: 10.1111/j.1469-8137.2008.02494.x
Endothelial nitric oxide synthase overexpression by neuronal cells in neurodegeneration: a link between inflammation and neuroprotection
Authors: De Palma Clara , Falcone Sestina , Panzeri Chris , Radice Sonia , Bassi Maria Teresa , Clementi Emilio
Published: April 2008

The roles of neuronal and inducible nitric oxide synthases in neurones have been extensively investigated; by contrast, the biological significance of endothelial nitric oxide synthase (eNOS) overexpression that occurs in several pathological conditions has not yet been studied. We have started addressing this issue in a cell model of neurodegeneration, i.e. human SKNBE neuroblastoma cells transfected with a mutant form of alsin, a protein causing an early‐onset type of amyotrophic lateral sclerosis, ALS2. We found that eNOS, which is endogenously expressed by these cells, was activated by tumour necrosis factor‐α (TNF‐α), a proinflammatory cytokine that plays important roles in ALS2 and several neurodegenerative diseases. The TNF‐α‐dependent eNOS activation occurred through generation, by sphingosine‐kinase‐1, of sphingosine‐1‐phosphate, stimulation of its membrane receptors and activation of Akt, as determined using small interference RNA and dominant negative constructs specific for the enzymes and receptors. eNOS activation by TNF‐α conferred cytoprotection from excitotoxicity and neurotoxic cues such as reactive oxygen species, endoplasmic reticulum stress, DNA damage, and mutated alsin itself. Our results suggest that overexpression of eNOS by neurones is a broad‐range protective mechanism activated during damage and establish a link of pathophysiological relevance between this enzyme and inflammation accompanying neurodegenerative diseases. These findings also question the concept that high NO output in the presence of oxidative stress leads always to peroxynitrite formation contributing to neurodegeneration.
Characterization of OPA1 isoforms isolated from mouse tissues
Authors: Akepati Vasudheva Reddy , Müller Eva‐Christina , Otto Albrecht , Strauss Holger M. , Portwich Michael , Alexander Christiane
Published: April 2008

OPA1, a nuclear encoded mitochondrial protein causing autosomal dominant optic atrophy, is a key player in mitochondrial fusion and cristae morphology regulation. In the present study, we have compared the OPA1 transcription and translation products of different mouse tissues. Unlike in humans, we found only two exons (4b and 5b) to be involved in alternative splicing. The relative abundance of the resulting four different splice variants is tissue‐dependent. Proteolytic cleavage by mitochondrial processing peptidase generates two long forms, isoforms 1 and 7, which lead to three short forms representing the end products after further proteolytic processing. In contrast, isoforms 5 and 8 are directly processed into their corresponding short forms. Short form 1 molecules form 184 kDa dimers, whereas all other isoforms contribute to 285 kDa complexes. Coiled‐coil domains of the OPA1 protein specifically homo‐associate and may be involved in the formation of these complexes. Furthermore, the region encoded by exon 5b inhibits the self‐association of coiled‐coil domain‐I. Finally, our data pinpoint isoform 1 as the, by far, most abundant isoform in the nervous tissue. We postulate that manipulation of isoform 1 protein levels in relation to the other isoforms induces changes in the mitochondrial network in the cell and therefore, mutations affecting the level of functional isoform 1 could lead to devastating effects on retinal ganglion cells.
Brain metabolism in adult chronic hydrocephalus
Authors: Kondziella Daniel , Sonnewald Ursula , Tullberg Mats , Wikkelso Carsten
Published: April 2008

Normal pressure hydrocephalus (NPH) is the most frequent form of chronic hydrocephalus in adults. NPH remains underdiagnosed although between 5% and 10% of all demented patients may suffer from this disorder. As dementia is an increasing demographic problem, treatable forms such as in NPH have become a central issue in neurology. Despite the traditional perception of hydrocephalus being a disorder of disturbed CSF dynamics, in NPH metabolic impairment seems at least as important. So far, the only valid animal model of NPH is chronic adult kaolin hydrocephalus. In this model, opening of alternative CSF outflow pathways leads to normal or near‐normal intracranial pressure and CSF outflow resistance. Yet, various metabolic disturbances cause ongoing ventricular enlargement and characteristic symptoms including cognitive decline and gait ataxia. Delayed hippocampal neuronal death, accumulation of beta‐amyloid and disturbed cholinergic neurotransmission may contribute to memory dysfunction. Compromised periventricular blood flow, decreased dopamine levels in the substantia nigra and damaged striatal GABAergic interneurons may reflect basal ganglia symptoms. At least in human hydrocephalus cerebrovascular co‐morbidity of the white matter plays an important role as well. It seems that in hydrocephalus from a certain ‘point of no return’ metabolic impairment becomes decoupled from CSF dynamics and, at least partly, self‐sustained. This is probably the reason why despite restored CSF circulation by shunting many patients with chronic hydrocephalus still suffer from severe neurological deficits. The present paper offers a comprehensive review of the experimental and clinical data suggesting metabolic disturbances in chronic hydrocephalus.
Tetrahydrobiopterin shows chaperone activity for tyrosine hydroxylase
Authors: Thöny Beat , Calvo Ana C. , Scherer Tanja , Svebak Randi M. , Haavik Jan , Blau Nenad , Martinez Aurora
Published: April 2008

Tyrosine hydroxylase (TH) is the rate‐limiting enzyme in the synthesis of catecholamine neurotransmitters. Primary inherited defects in TH have been associated with l‐DOPA responsive and non‐responsive dystonia and infantile parkinsonism. In this study, we show that both the cofactor (6R)‐l‐erythro‐5,6,7,8‐tetrahydrobiopterin (BH4) and the feedback inhibitor and catecholamine product dopamine increase the kinetic stability of human TH isoform 1 in vitro. Activity measurements and synthesis of the enzyme by in vitro transcription–translation revealed a complex regulation by the cofactor including both enzyme inactivation and conformational stabilization. Oral BH4 supplementation to mice increased TH activity and protein levels in brain extracts, while the Th‐mRNA level was not affected. All together our results indicate that the molecular mechanisms for the stabilization are a primary folding‐aid effect of BH4 and a secondary effect by increased synthesis and binding of catecholamine ligands. Our results also establish that orally administered BH4 crosses the blood–brain barrier and therapeutic regimes based on BH4 supplementation should thus consider the effect on TH. Furthermore, BH4 supplementation arises as a putative therapeutic agent in the treatment of brain disorders associated with TH misfolding, such as for the human TH isoform 1 mutation L205P.
Histamine induces neural stem cell proliferation and neuronal differentiation by activation of distinct histamine receptors
Authors: Molina‐Hernández Anayansi , Velasco Iván
Published: April 2008

Histamine has neurotransmitter/neuromodulator functions in the adult brain, but its role during CNS development has been elusive. We studied histamine effects on proliferation, cell death and differentiation of neuroepithelial stem cells from rat cerebral cortex in vitro. RT‐PCR and Western blot experiments showed that proliferating and differentiated cells express histamine H1, H2 and H3 receptors. Treatments with histamine concentrations (100 nM–1 mM) caused significant increases in cell numbers without affecting Nestin expression. Cell proliferation was evaluated by BrdU incorporation; histamine caused a significant increase dependent on H2 receptor activation. Apoptotic cell death during proliferation was significantly decreased at all histamine concentrations, and cell death was promoted in a concentration‐dependent manner by histamine in differentiated cells. Immunocytochemistry studies showed that histamine increased 3‐fold the number of neurons after differentiation, mainly by activation of H1 receptor, and also significantly decreased the glial (astrocytic) cell proportion, when compared to control conditions. In summary, histamine increases cell number during proliferative conditions, and has a neuronal‐differentiating action on neural stem cells, suggesting that the elevated histamine concentration reported during development might play a role in cerebrocortical neurogenesis, by activation of H2 receptors to promote proliferation of neural precursors, and favoring neuronal fate by H1‐mediated stimulation.
Pin1 promotes cell death in NGF‐dependent neurons through a mechanism requiring c‐Jun activity
Authors: Barone Maria Cecilia , Desouza Lynette A. , Freeman Robert S.
Published: April 2008

Developing neurons deprived of trophic support undergo apoptosis mediated by activation of c‐Jun N‐terminal kinases (JNK) and c‐Jun, induction of the Bcl‐2 homology 3‐only protein BimEL, Bax‐dependent loss of mitochondrial cytochrome c, and caspase activation. However, the mechanisms that regulate each of these events are only partially understood. Here we show that the prolyl isomerase Pin1 functions as a positive regulator of neuronal death through a c‐Jun‐dependent mechanism. Ectopic Pin1 promoted caspase‐dependent death of NGF‐maintained neurons that was associated with an accumulation of Ser63‐phosphorylated c‐Jun in neuronal nuclei and was partially dependent on Bax. Downregulating Pin1 prior to NGF withdrawal suppressed the accumulation of phosphorylated c‐Jun, inhibited the release of cytochrome c, and significantly delayed cell death. Pin1 knockdown inhibited NGF deprivation‐induced death to a similar extent in Bim (+/+) and Bim (−/−) neurons. The protective effect of Pin1 knockdown was significantly greater than that caused by loss of Bim and nearly identical to that caused by a dominant negative form of c‐Jun. Finally, cell death induced by ectopic Pin1 was largely blocked by expression of dominant negative c‐Jun. These results suggest a novel mechanism by which Pin1 promotes cell death involving activation of c‐Jun.
Breeding behaviour, home range and habitat selection in Rock Firefinches Lagonosticta sanguinodorsalis in the wet and dry season in central Nigeria
Authors: BRANDT MIRIAM J. , CRESSWELL WILL
Published: April 2008

Knowledge of a species’ movement behaviour and habitat choice is a prerequisite for assessing its ecological requirements to plan successful conservation strategies. Little is known about these factors in the Rock Firefinch, a recently described species which is probably endemic to the Jos Plateau in central Nigeria. We investigated home range size, habitat use and breeding behaviour of the Rock Firefinch in Amurum forest reserve in central Nigeria during the wet (August–October) and the dry season (November–December) using radiotracking. Birds showed high site fidelity. They mainly moved alone or in pairs but did not have exclusive home ranges. Home range size tended to be larger during the dry season due to long movements to water sources. Birds generally preferred inselberg habitat and avoided farmland. During the dry season they additionally utilized gallery forests where water was readily available, and as a result of having to cross scrub savannah to get to water, scrub savannah was also more heavily used during the dry season. Birds bred between the late rainy (September–October) and the early dry season (November). Nest‐sites were associated with rocky boulders. Both sexes contributed to incubation. Daily egg survival rate calculated using the Mayfield method was 0.89 (0.83–0.95 95% confidence interval); no nests failed during the chick stage, but sample size was only four nests. Of all 14 nests found, 50% were depredated and only 29% of breeding attempts succeeded in producing Rock Firefinch chicks. A second breeding attempt was recorded when the first one failed. Chick production just about compensated adult mortality (measured in a separate study at the site) such that the population is probably stable at present. However, given the large uncertainty in our underlying assumptions, more data are needed to confirm this. We suggest that the presence of inselberg habitat in close proximity to water sources is the essential and limiting resource for this species.
Movements of wintering Dunlin Calidris alpina and changing habitat availability in an agricultural wetland landscape
Authors: TAFT ORIANE W. , SANZENBACHER PETER M. , HAIG SUSAN M.
Published: April 2008

Few studies have assessed how the dynamics of wetland bird movements relate to changing resource availability, particularly at more than one spatial scale. Within western Oregon's Williamette Valley, we examined winter resident Dunlin Calidris alpina movements in relation to a decrease in availability of preferred shorebird foraging habitat from early to late winter of 1999–2000. By tracking movements of 15 (early winter) and 12 (late winter) radiomarked individuals, we calculated home ranges and characterized presence/absence of a preference for shorebird foraging habitat during each winter period. Between periods, we compared: (1) percentage of shorebird habitat in home ranges to its availability in the landscape (regional preference), (2) percentage of radio locations in shorebird habitat to its availability within home ranges (local preference) and (3) relative use of roost sites. Concurrent with a 75% decrease in available shorebird habitat from early to late winter, average home range sizes increased by a factor of 3.8. At a regional scale, home ranges in early winter included a significantly greater percentage of shorebird foraging habitat than was available in the wider landscape. However, by late winter, the percent of shorebird habitat in home ranges did not match availability in the landscape. At the local scale, for both winter periods Dunlin were located in shorebird foraging habitat more often than expected given availability of habitat within home ranges [Correction added after online pub‐lication 23 May 2008: sentence amended]. An increase in the number of roosts used from early to late winter implies possible reliance on additional sites in late winter for foraging opportunities. Results suggest that wet, unvegetated habitat is sought by Dunlin throughout winter, but individuals could not select home ranges in late winter that fully compensated for seasonal loss of habitat.
Age‐related increase of superoxide generation in the brains of mammals and birds
Authors: Sasaki Toru , Unno Keiko , Tahara Shoichi , Shimada Atsuyoshi , Chiba Yoichi , Hoshino Minoru , Kaneko Takao
Published: April 2008

Oxidative stress, an imbalance between endogenous levels of oxygen radicals and antioxidative defense, increases with aging. However, it is not clear which of these two factors is the more critical. To clarify the production of oxygen radicals increases with age, we examined oxygen radical‐dependent chemiluminescent signals in ex vivo brain slices using a novel photonic imaging method. The chemiluminescent intensity was significantly decreased by the membrane permeable superoxide dismutase (SOD)/catalase mimic, but not by Cu,Zn‐SOD. Inhibitors for complex I, III, and IV of the mitochondrial electron transport chain transiently enhanced the chemiluminescent signal. The superoxide‐dependent chemiluminescent intensity in senescence accelerated mouse (SAM) brain tissues increases with age. Moreover, the slope of the age‐dependent increase was steeper in SAMP10, a strain characterized by a short lifespan and atrophy in the frontal cerebral cortex, than the senescence‐resistant strain SAMR1, which has a longer lifespan. An increase in chemiluminescence with age was also observed in C57/BL6 mice, Wistar rats, and pigeons, although levels of chemiluminescence were lower in the pigeons than murines. The rate of age‐related increases of superoxide‐dependent chemiluminescence was inversely related to the maximum lifespan of the animals. The activity of superoxide dismutase was unchanged during the aging process in the brain. This suggested that superoxide production itself may increase with age. We speculated that reactive oxygen may be a signal to determine the aging process.
Apolipoprotein D is involved in the mechanisms regulating protection from oxidative stress
Authors: Ganfornina Maria D. , Do Carmo Sonia , Lora Jose M. , Torres‐Schumann Sonia , Vogel Marci , Allhorn Maria , González Constancio , Bastiani Michael J. , Rassart Eric , Sanchez Diego
Published: April 2008

Many nervous system pathologies are associated with increased levels of apolipoprotein D (ApoD), a lipocalin also expressed during normal development and aging. An ApoD homologous gene in Drosophila, Glial Lazarillo, regulates resistance to stress, and neurodegeneration in the aging brain. Here we study for the first time the protective potential of ApoD in a vertebrate model organism. Loss of mouse ApoD function increases the sensitivity to oxidative stress and the levels of brain lipid peroxidation, and impairs locomotor and learning abilities. Human ApoD overexpression in the mouse brain produces opposite effects, increasing survival and preventing the raise of brain lipid peroxides after oxidant treatment. These observations, together with its transcriptional up‐regulation in the brain upon oxidative insult, identify ApoD as an acute response protein with a protective and therefore beneficial function mediated by the control of peroxidated lipids.
SPECIES DISCRIMINATION AND EVOLUTIONARY MODE OF BUCHIA (BIVALVIA: BUCHIIDAE) FROM UPPER JURASSIC–LOWER CRETACEOUS STRATA OF GRASSY ISLAND, BRITISH COLUMBIA, CANADA
Authors: GREY MELISSA , HAGGART JAMES W. , SMITH PAUL L.
Published: April 2008

Abstract:  Buchiid bivalves are geographically widespread in Upper Jurassic and Lower Cretaceous strata of the Northern Hemisphere. They are often abundant and their short stratigraphic ranges make them ideal biostratigraphic index fossils; these characteristics also render them useful for study of evolutionary patterns. We used multivariate methods to determine if we could discriminate between species of Buchia and examine how morphological characters change through time within the genus. Using ten morphological characters to describe shell shape and size, we tested for taxonomic differences and morphologic change in populations of buchiids collected from a single stratigraphic section on Grassy Island, located along the west coast of Vancouver Island, British Columbia. Morphometric analysis utilized traditional morphological metrics and techniques, including linear and angular measurements as well as Fourier (outline shape) analyses. Phenetic discrimination revealed considerable overlap among the recognized species in the morphospace, as well as a fairly low discriminatory power between species when compared as a group using a step‐wise canonical variate analysis. Step‐wise discriminant analyses between species pairs gave rise to much higher classification rates, suggesting that different characters are important for distinguishing between different species pairs. Our results also indicate that single individuals and small sample sizes of Buchia specimens are insufficient for biostratigraphic discrimination (unless other rarely preserved features such as the hinge and bysuss ear are available) and that a number of previously described species variants may not be taxonomically valid. A biolog using the multivariate axis that best discriminates between species (CV1) and a random walk‐based test using a Hurst estimate analysis indicate a gradualistic evolutionary mode for the Buchia species of Grassy Island. Shell shape and size of buchiids do not appear to be closely tied to lithofacies changes over the c. 10 myr time interval, suggesting that ecophenotypic variation (as it relates to substrate changes) probably had minimal influence on morphology.
THE TERGOMYAN MOLLUSC CARCASSONNELLA FROM THE UPPER ORDOVICIAN OF GIRVAN, SCOTLAND
Authors: EBBESTAD JAN OVE R.
Published: April 2008

Abstract:  The tergomyan genus CarcassonnellaHorný and Peel, 1996 is common in and characteristic of the Mediterranean Province in peri‐Gondwanan terranes during the late Tremadoc and Arenig. It is united with other small, slit‐bearing cyrtonellids in the Carcassonnellidae Horný, 1997b, of which BaltiscanellaHorný, 1997b from the Arenig of the Oslo Region, Norway, and Sarkanella from the Caradoc of the Siljan District, Sweden has been recognized outside the Mediterranean Province. The most inclusive view of the Carcassonnellidae unites PeelerophonYochelson, 1982, CarcassonnellaHorný and Peel, 1996, SarkanellaHorný, 1997a, BaltiscanellaHorný, 1997b, and TachillanellaHorný, 1997b. Patterns of distribution of genera in the family are obscured, however, by widely different phylogenetic relationships presented in the literature. Here, Carcassonnella multilineata (Reed, 1920) is documented in the upper Whitehouse and Drummuck subgroups of the Girvan district, Midland Valley of Scotland, being the first record of the genus outside peri‐Gondwana. Its enigmatic occurrence on the edge of Laurentia is opposed to the occurrence of low latitude benthic faunas in higher latitudes during this time interval (the Boda Event). It is likely, therefore, that the genus spread from the ancient stock found on the Perunican microcontinent as this drifted away from Gondwana in the mid‐Caradoc.
CLADISTIC ANALYSIS OF THE SUBORDER CONULARIINA MILLER AND GURLEY, 1896 (CNIDARIA, SCYPHOZOA; VENDIAN–TRIASSIC)
Authors: DE MORAES LEME JULIANA , GUIMARÃES SIMÕES MARCELLO , CARLOS MARQUES ANTONIO , VAN ITEN HEYO
Published: April 2008

Abstract:  Results of a cladistic analysis of the suborder Conulariina Miller and Gurley, 1896, a major extinct (Vendian–Triassic) group of scyphozoan cnidarians, are presented. The analysis sought to test whether the three conulariid subfamilies (Conulariinae Walcott, 1886, Paraconulariinae Sinclair, 1952 and Ctenoconulariinae Sinclair, 1952) recognized in the Treatise on Invertebrate Paleontology (TIP) are monophyletic. A total of 17 morphological characters were scored for 16 ingroup taxa, namely the genera Archaeoconularia, Baccaconularia, Climacoconus, Conularia, Conulariella, Conularina, Ctenoconularia, Eoconularia, Glyptoconularia, Metaconularia, Notoconularia, Paraconularia, Pseudoconularia, Reticulaconularia, Teresconularia and Vendoconularia. The extant medusozoan taxa Cubozoa, Stauromedusae, Coronatae and Semaeostomeae served as outgroups. Unweighted analysisof the data matrix yielded 1057 trees, and successive weighting analysis resulted in one of the 1057 original trees. The ingroup is monophyletic with two autapomorphies: (1) the quadrate geometry of the oral region; and (2) the presence of a mineralized (phosphatic) periderm. Within the ingroup, the clade (Vendoconularia, Teresconularia, Conularina, Eoconularia) is supported by the sinusoidal longitudinal geometry of the transverse ridges, and the much larger clade (Baccaconularia, Glyptoconularia, Metaconularia, Pseudoconularia, Conularia, Ctenoconularia, Archaeoconularia, Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the presence of external tubercles, which, however, were lost in the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia). As proposed by Van Iten et al. (2000), the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the termination and alternation of the transverse ribs in the corner sulcus. The previously recognized subfamilies Conulariinae, Paraconulariinae and Ctenoconulariinae were not recovered from this analysis. The diagnostic features of Conulariinae (continuation of the transverse ornament across the corner sulcus and lack of carinae) and Ctenoconulariinae (presence of carinae) are symplesiomorphic or homoplastic, and Paraconulariinae is polyphyletic. The families Conulariellidae Kiderlen, 1937 and Conulariopsidae Sugiyama, 1942, also recognized in the TIP, are monogeneric, and since they provide no additional phylogenetic information, should be abandoned.
AFFINITIES OF MIOCENE WATERFOWL (ANATIDAE: MANUHERIKIA, DUNSTANETTA AND MIOTADORNA) FROM THE ST BATHANS FAUNA, NEW ZEALAND
Authors: WORTHY TREVOR H. , LEE MICHAEL S. Y.
Published: April 2008

Abstract:  The recently described St Bathans Fauna, from the Manuherikia Group, Early–Middle Miocene, 19–16 Ma, New Zealand, includes six anatid taxa. Here we present detailed morphological descriptions of all available skeletal elements of the three best represented anatids: Manuherikia lacustrina (551 specimens), Dunstanetta johnstoneorum (7 specimens), and Miotadorna sanctibathansi (115 specimens). The affinities of these taxa, and of the similar‐aged European taxon Mionetta blanchardi, are evaluated with phylogenetic analyses using a dataset of 133 characters (128 osteological, 5 integumental) and 57 terminal taxa. Representatives of all main anatid groups were included, with dense sampling of Australasian taxa including the recently extinct New Zealand forms (Cnemiornis, Chenonetta finschi), and relatively primitive taxa (anserines, Dendrocygna, oxyurines, tadornines). Analyses were conducted with no constraints, and with certain taxa constrained to conform to arrangements supported by multiple independent genetic studies. In the preferred (constrained) analyses: (1) anserines were the most basal anatids; (2) the four Tertiary fossil taxa were more derived than anserines and Dendrocygna; and (3) the European Mionetta blanchardi was basal to an oxyurine clade. The New Zealand fossils Manuherikia and Dunstanetta either associated with this oxyurine clade or formed separate lineages of an approximately oxyurine evolutionary grade, depending on whether diving characters were included or excluded. Similarly, Biziura, Thalassornis, and a Stictonetta–Malacorhynchus clade either associated with oxyurines or formed independent lineages of approximately oxyurine grade. Above oxyurines, a well‐supported clade groups Miotadorna with Tadorna species exclusive of T. radjah. These results cast doubt on the distinctiveness of Dendrocheninae Livezey and Martin, 1988, and instead suggest oxyurine affinities for the Miocene fossils Mionetta, Dendrochen, Manuherikia and Dunstanetta, and the modern Biziura, Thalassornis, Oxyura, Nomonyx, Stictonetta and Malacorhynchus. The association of Mionetta with oxyurines indicates that the divergence between oxyurines and higher anatids occurred around 25 Ma, while the position of Miotadorna within Tadorna indicates that the basal divergence between living Tadorna occurred by the Early–Middle Miocene; together, these two dates indicate that many basal splits within anatids occurred within a short interval during the Miocene.
PHYLOGENETIC POSITION AND MORPHOLOGY OF THECAE AND CYSTS OF SCRIPPSIELLA (DINOPHYCEAE) SPECIES IN THE EAST CHINA SEA1
Authors: Gu Haifeng , Sun Jun , Kooistra Wiebe H. C. F. , Zeng Runying
Published: April 2008

Resting cysts of the marine phytoplanktonic dinoflagellate Scrippsiella spp. are encountered in coastal habitats and shallow seas all over the world. Identification of Scrippsiella species requires information on cyst morphology because the plate pattern of the flagellated cell is conserved. Cysts from sediments of the East China Sea were identified based on traits from both the cysts and the thecal patterns of germinated cells. Calcareous cysts belonged predominantly to S. trochoidea (F. Stein) A. R. Loebl., S. rotunda J. Lewis, and S. precaria Montresor et Zingone. The former two species also produced smooth and noncalcified cysts in the field. A new species, S. donghaienis H. Gu sp. nov, was obtained from six noncalcified cysts with organic spines. These cysts are spherical, full of pale white and greenish granules with a mesoepicystal archeopyle. The vegetative cells consist of a conical epitheca and a round hypotheca with a plate formula of po, x, 4′, 3a, 7′′, 6c (5c + t), 6 s, 5′′′, 2′′′′ and are morphologically indistinguishable from S. trochoidea. Results of internal transcribed spacer (ITS) sequence comparisons revealed that S. donghaienis was distinct from the S. trochoidea complex and appeared nested within the Calciodinellum/Calcigonellum clade. Culture experiments showed that the presence of a red body in the cyst and the shape of the archeopyle were constant within cell lines from one generation to the next, while the morphological features of the cyst wall, such as calcification and spine shape, appeared to be phenotypically plastic.
SPATIAL HETEROGENEITY OF PHOTOSYNTHETIC ACTIVITY WITHIN DISEASED CORALS FROM THE GREAT BARRIER REEF1
Authors: Roff George , Ulstrup Karin E. , Fine Maoz , Ralph Peter J. , Hoegh‐Guldberg Ove
Published: April 2008

Morphological diagnosis and descriptions of seven disease‐like syndromes affecting scleractinian corals were characterized from the southern Great Barrier Reef (GBR). Chl a fluorescence of PSII was measured using an Imaging‐PAM (pulse amplitude modulated) fluorometer, enabling visualization of the two‐dimensional variability in the photophysiology of endosymbiotic dinoflagellates (zooxanthellae) by measuring rapid light curves. Three of four syndromes associated with active tissue loss (type a) were spatially homogenous (white syndrome, brown band, and skeletal eroding band), with no impact on the photochemical function of zooxanthellae populations at or behind the lesion borders. However, a decline in maximum quantum yield (Fv/Fm) and elevated levels of maximum nonphotochemical quenching (NPQmax) occurred in visually healthy tissue of black band disease adjacent to the lesion borders, possibly due to hypoxic conditions caused by the black band cyanobacterial mat. Two out of three syndromes associated with pathological change of intact tissue with no active tissue loss (type b) showed variable photophysiological responses (neoplasia and pigmentation response). Only the bleached foci associated with white patch syndrome appeared to impact primarily on the symbiotic dinoflagellates, as evidenced by declines in minimum fluorescence (F0) and maximum quantum yield (Fv/Fm), with no indication of degeneration in the host tissues. Our results suggest that for the majority of coral syndromes from the GBR, pathogenesis occurs in the host tissue, while the impact on the zooxanthellae populations residing in affected corals is minimal.
PRESENCE OF ALGAE IN FRESHWATER ICE COVER OF FLUVIAL LAC SAINT‐PIERRE (ST. LAWRENCE RIVER, CANADA)1
Authors: Frenette Jean‐Jacques , Thibeault Patrice , Lapierre Jean‐François , Hamilton Paul B.
Published: April 2008

Winter ice cover is a fundamental feature of north temperate aquatic systems and is associated with the least productive months of the year. Here we describe a previously unknown freshwater habitat for algal and microbial communities in the ice cover of the freshwater St. Lawrence River, Quebec, Canada. Sampling performed during winter 2005 revealed the presence of viable algal cells, such as Aulacoseira islandica (O. Müll.) Simonsen (Bacillariophyceae), and microbial assemblage growing in the ice and at the ice–water interface. Vertical channels (1–5 mm wide) containing algae were also observed. Concentrations of chl a ranged between 0.5 and 169 μg · L−1 of melted ice, with maximal concentrations found in the lower part of the ice cores. These algae have the potential to survive when ice breakup occurs and reproduce rapidly in spring/summer conditions. Freshwater ice algae can thus contribute to in situ primary production, biodiversity, and annual carbon budget in various habitats of riverine communities.
DECREASE IN DYNAMIC VISCOSITY AND AVERAGE MOLECULAR WEIGHT OF ALGINATE FROM LAMINARIA DIGITATA DURING ALKALINE EXTRACTION1
Authors: Vauchel Peggy , Arhaliass Abdellah , Legrand Jack , Kaas Raymond , Baron Régis
Published: April 2008

Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1–4 h in duration were determined, indicating depolymerization of alginates: average molecular weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological properties of the extracted alginates.
MORPHOLOGY AND MOLECULAR PHYLOGENY OF A NEW MARINE SAND‐DWELLING PROROCENTRUM SPECIES, P. TSAWWASSENENSE (DINOPHYCEAE, PROROCENTRALES), FROM BRITISH COLUMBIA, CANADA1
Authors: Hoppenrath Mona , Leander Brian S.
Published: April 2008

A new marine benthic, sand‐dwelling Prorocentrum species from the temperate region of the Pacific coast of British Columbia, Canada, is described using LM and EM and molecular phylogenetic analyses. The cells have a broad oval shape, 40.0–55.0 μm long and 30.0–47.5 μm wide, and a wide U‐shaped periflagellar area on the right thecal plate. The left thecal plate consists of a straighter apical outline in the form of a raised ridge. Five to six delicate apical spines in the center of the periflagellar area are present. The nucleus is located in the posterior region of the cell, and a conspicuous pusule is located in the anterior region of the cell. The cells have golden‐brown chloroplasts with a compound, intrachloroplast pyrenoid that lacks a starch sheath. The thecal plates are smooth with round pores of two different sizes. The larger pores are arranged in a specific pattern of radial rows that are evenly spaced around the plate periphery and of irregular rows (or double rows) that form an incomplete “V” at the apical end of the plates. Large pores are absent in the center of the left and right thecal plates. The intercalary band is striated transversely and also has faint horizontal striations. Trichocysts and two types of mucocysts are present. The molecular phylogenetic position of Prorocentrum tsawwassenense sp. nov. was inferred using SSU rDNA sequences. This new species branched with high support in a Prorocentrum clade containing both benthic and planktonic species.
NEW MARINE MEMBERS OF THE GENUS HEMISELMIS (CRYPTOMONADALES, CRYPTOPHYCEAE)1
Authors: Lane Christopher E. , Archibald John M.
Published: April 2008

Cryptomonads are a ubiquitous and diverse assemblage of aquatic flagellates. The relatively obscure genus Hemiselmis includes some of the smallest of these cells. This genus contained only two species until 1967, when Butcher described seven new marine species mainly on the basis of observations with the light microscope. However, from these seven taxa, only H. amylifera and H. oculata were validly published. Additionally, the features Butcher used to distinguish species have since been questioned, and the taxonomy within Hemiselmis has remained clouded due to the difficulty in unambiguously applying his classification and validating many of his species. As a result, marine strains are often placed into one of three species—H. rufescens Parke, H. virescens Droop, or the invalid H. brunnescens Butcher—based on cell color alone. Here we applied microscopic and molecular tools to 13 publicly available Hemiselmis strains in an effort to clarify species boundaries. SEM failed to provide sufficient morphological variation to distinguish species of Hemiselmis, and results from LM did not correlate with clades found using both molecular phylogenetic and nucleomorph genome karyotype analysis, indicating a high degree of morphological plasticity within species. On the basis of molecular characters and collection geography we recognize four new marine species of Hemiselmis—H. cryptochromatica sp. nov., H. andersenii sp. nov., H. pacifica sp. nov., and H. tepida sp. nov.—from the waters around North America.
TEMPERATURE EFFECTS ON MICROALGAL PHOTOSYNTHESIS‐LIGHT RESPONSES MEASURED BY O2 PRODUCTION, PULSE‐AMPLITUDE‐MODULATED FLUORESCENCE, AND 14C ASSIMILATION1
Authors: Hancke Kasper , Hancke Torunn B. , Olsen Lasse M. , Johnsen Geir , Glud Ronnie N.
Published: April 2008

Short‐term temperature effects on photosynthesis were investigated by measuring O2 production, PSII‐fluorescence kinetics, and 14C‐incorporation rates in monocultures of the marine phytoplankton species Prorocentrum minimum (Pavill.) J. Schiller (Dinophyceae), Prymnesium parvum f. patelliferum (J. C. Green, D. J. Hibberd et Pienaar) A. Larsen (Coccolithophyceae), and Phaeodactylum tricornutum Bohlin (Bacillariophyceae), grown at 15°C and 80 μmol photons · m−2 · s−1. Photosynthesis versus irradiance curves were measured at seven temperatures (0°C–30°C) by all three approaches. The maximum photosynthetic rate (PCmax) was strongly stimulated by temperature, reached an optimum for Pro. minimum only (20°C–25°C), and showed a similar relative temperature response for the three applied methods, with Q10 ranging from 1.7 to 3.5. The maximum light utilization coefficient (αC) was insensitive or decreased slightly with increasing temperature. Absolute rates of O2 production were calculated from pulse‐amplitude‐modulated (PAM) fluorometry measurements in combination with biooptical determination of absorbed quanta in PSII. The relationship between PAM‐based O2 production and measured O2 production and 14C assimilation showed a species‐specific correlation, with 1.2–3.3 times higher absolute values of PCmax and αC when calculated from PAM data for Pry. parvum and Ph. tricornutum but equivalent for Pro. minimum. The offset seemed to be temperature insensitive and could be explained by a lower quantum yield for O2 production than the theoretical maximum (due to Mehler‐type reactions). Conclusively, the PAM technique can be used to study temperature responses of photosynthesis in microalgae when paying attention to the absorption properties in PSII.
Familiality of major depressive disorder and gender differences in comorbidity
Authors: Verhagen M. , Van Der Meij A. , Franke B. , Vollebergh W. , De Graaf R. , Buitelaar J. , Janzing J. G.
Published: April 2008

Objective:  Gender differences exist in the prevalence and psychiatric comorbidity of major depressive disorder (MDD). This study investigates whether familiality of MDD contributes to observed gender differences in comorbidity.

Method:  Familial (f‐MDD) and non‐familial (nf‐MDD) MDD cases from a population sample were assessed for comorbid dysthymia, anxiety disorders and alcohol‐related disorders using the Composite International Diagnostic Interview (CIDI). Logistic regression analyses were performed to examine the effect of f‐MDD on gender differences in comorbidity, adjusted for confounders.

Results:  Women with f‐MDD reported significantly more comorbid dysthymia and generalized anxiety disorder (GAD) than their male counterparts; women with nf‐MDD reported significantly more comorbid simple phobias and agoraphobia than their male counterparts. Gender differences in comorbid panic disorder and alcohol‐related disorders occurred independently of the familial load. Adjustment for age of onset, severity and recurrence of MDD did not change these results.

Conclusion:  Models to explain comorbidity patterns of MDD differ by gender. Familiality of MDD should be taken into account.
Photo‐induced hydrophilicity enhances initial cell behavior and early bone apposition
Authors: Sawase Takashi , Jimbo Ryo , Baba Koumei , Shibata Yasuaki , Ikeda Tohru , Atsuta Mitsuru
Published: April 2008

Objective: The anatase form of titanium dioxide (TiO2) exhibits photo‐induced hydrophilicity when it is irradiated with ultraviolet (UV) light. In the present study, the effect of photo‐induced hydrophilicity on initial cell behavior and bone formation was evaluated.

Materials and methods: Plasma source ion implantation method and post‐annealing were employed for coating the anatase form of TiO2 to the surface of the titanium disk and implant. Half of the disks and implants were illuminated with UV for 24 h beforehand, whereas the other halves were blinded and used as controls. Photo‐induced hydrophilicity was confirmed by a static wettability assay. The effects of this hydrophilicity on cell behavior were evaluated by means of cell attachment, proliferation and morphology using pluripotent mesenchymal precursor C2C12 cells. Thereafter, bone formation around the hydrophilic implant inserted in the rabbit tibia was confirmed histomorphometrically.

Results: The water contact angle of the photo‐induced hydrophilic disk decreased markedly from 43.5° to 0.5°. Cell attachment and proliferation on this hydrophilic disk showed significant improvement. The cell morphology on this hydrophilic disk was extremely flattened, with an elongation of the lamellipodia, whereas a round/spherical morphology was observed on the control disk. The photo‐induced hydrophilic implant enhanced the bone formation with the bone‐to‐metal contact of 28.2% after 2 weeks of healing (control: 17.97%).

Conclusion: The photo‐induced hydrophilic surface used in the current study improves the initial cell reactions and enhances early bone apposition to the implant.
Vivosorb®, Bio‐Gide®, and Gore‐Tex® as barrier membranes in rat mandibular defects: an evaluation by microradiography and micro‐CT
Authors: Gielkens Pepijn F. M. , Schortinghuis Jurjen , De Jong Johan R. , Raghoebar Gerry M. , Stegenga Boudewijn , Bos Ruud R. M.
Published: April 2008

Objectives: The objectives of this study were to determine whether a new degradable synthetic barrier membrane (Vivosorb®) composed of poly(dl‐lactide‐ɛ‐caprolactone) (PDLLCL) can be useful in implant dentistry and to compare it with collagen and expanded polytetrafluoroethylene (ePTFE) membranes.

Material and methods: In 192 male Sprague–Dawley rats, a standardized 5 mm circular defect was created through the right angle of the mandible. New bone formation was evaluated by post‐mortem microradiography and micro‐CT (μCT) imaging. Four groups (control, PDLLCL, collagen, ePTFE) were evaluated at three time intervals (2, 4, and 12 weeks). In the membrane groups the defects were covered; in the control group the defects were left uncovered. Data were analysed using a multiple regression model.

Results: New bone formation could be detected by post‐mortem microradiography in 130 samples and by μCT imaging in 112 samples. Bone formation was progressive in 12 weeks, when the mandibular defect was covered with a membrane. Overall, more bone formation was observed underneath the collagen and ePTFE membranes than the PDLLCL membranes.

Conclusions: In contrast to uncovered mandibular defects, substantial bone healing was observed in defects covered with a PDLLCL membrane. However, bone formation in PDLLCL‐covered defects tended to be less than in the defects covered with collagen or ePTFE. The high variation in the PDLLCL samples at 12 weeks may be caused by the moderate adherence of this membrane to bone compared with collagen. These results indicate that further study is needed to optimize the properties of PDLLCL membranes.
Immediate transmucosal implant placement in molar extraction sites: a 12‐month prospective multicenter cohort study
Authors: Cafiero C. , Annibali S. , Gherlone E. , Grassi F. R. , Gualini F. , Magliano A. , Romeo E. , Tonelli P. , Lang N. P. , Salvi G. E. ,   on behalf of the ITI Study Group Italia
Published: April 2008

Aim: To assess the clinical and radiographic outcomes of immediate transmucosal placement of implants into molar extraction sockets.

Study design: Twelve‐month multicenter prospective cohort study.

Material and methods: Following molar extraction, tapered implants with an endosseous diameter of 4.8 mm and a shoulder diameter of 6.5 mm were immediately placed into the sockets. Molars with evidence of acute periapical pathology were excluded. After implant placement and achievement of primary stability, flaps were repositioned and sutured allowing a non‐submerged, transmucosal healing. Peri‐implant marginal defects were treated according to the principles of guided bone regeneration (GBR) by means of deproteinized bovine bone mineral particles in conjunction with a bioresrobable collagen membrane. Standardized radiographs were obtained at baseline and 12 months thereafter. Changes in depth and width of the distance from the implant shoulder (IS) and from the alveolar crest (AC) to the bottom of the defect (BD) were assessed.

Results: Eighty‐two patients (42 males and 40 females) were enrolled and followed for 12 months. They contributed with 82 tapered implants. Extraction sites displayed sufficient residual bone volume to allow primary stability of all implants. Sixty‐four percent of the implants were placed in the areas of 36 and 46. GBR was used in conjunction with the placement of all implants. No post‐surgical complications were observed. All implants healed uneventfully yielding a survival rate of 100% and healthy soft tissue conditions after 12 months. Radiographically, statistically significant changes (P<0.0001) in mesial and distal crestal bone levels were observed from baseline to the 12‐month follow‐up.

Conclusions: The findings of this 12‐month prospective cohort study showed that immediate transmucosal implant placement represented a predictable treatment option for the replacement of mandibular and maxillary molars lost due to reasons other than periodontitis including vertical root fractures, endodontic failures and caries.
Caries increment in children aged 3–5 years in relation to parents’ dental attitudes: Oslo, Norway 2002 to 2004
Authors: Skeie Marit S. , Espelid Ivar , Riordan Paul J. , Klock Kristin S.
Published: April 2008

Abstract –  Objectives:  To assess the relationship between parents’ dental attitudes and the caries increment in their children from the age of 3 to 5 years.

Methods:  Data based on parental questionnaires and dental examinations were collected from children participating in a follow‐up study from age 3 years (n = 354) in 2002 to 5 years (n = 304) in 2004. The children were categorized as western‐native (WN) and immigrants (IM). The items used were significantly related to caries experience in a multicentre study [Pine et al. (2004)Community Dent Health, vol. 21, pp. 121–30]. The responses to attitudinal items were weighted as positive if they would promote good dental health, and negative if not. Composite attitudinal variables relating to hygiene, diet and indulgence were calculated as a summation of the weighted responses to selected items. Regression analyses (bivariate and multiple) were performed to assess associations during the period between the attitudinal predictors/other control variables and caries increment (Δd3‐5mfs).

Results:  Bivariate logistic regression analyses revealed that ‘Attitude to Diet’ and ‘Parental Indulgence’ were clearly related to caries increment. The more exposed children were to negative parental attitudes, the higher the OR. ‘Attitude to Diet’ also persisted in a multiple logistic regression model, showing a higher OR value than caries experience. ‘Immigrant Status’ was the most potent predictor of caries increment. Parents were found to be more indulgent among IM than among WN groups.

Conclusion:  Parental dental attitudes are clearly shown to be associated with caries increment in early childhood. The relationship is of such strength that it deserves to be taken into account in future preventive dental strategies.