bluuebunny/crossref_metadata_2025_split huggingface dataset:
NOSTOC (CYANOPHYTA) PRODUCTIVITY IN OREGON STREAM ECOSYSTEMS: INVERTEBRATE INFLUENCES AND DIFFERENCES BETWEEN MORPHOLOGICAL TYPES1
Authors: Ward Amelia K. , Dahm Clifford N. , Cummins Kenneth W. 
Published: August 2010

ABSTRACT Nostoc parmelioides colonies housing dipteran larvae (Cricotopus) had higher rates of weight specific photosynthesis than colonies without the larvae. A change in colony shape, which allowed the alga to be exposed to higher light intensities, occurred, in the presence of the larvae. This change in morphology together with potential nutrient additions by the larvae and other effects may have caused the increase in photosynthetic rates. Nostoc colonies were typically found in open areas of small streams in western Oregon mountains where the ability to respond to high light would be advantageous in supporting the metabolically expensive process of nitrogen fixation.
LIGHT AND TEMPERATURE AS FACTORS REGULATING SEASONAL GROWTH AND DISTRIBUTION OF ULOTHRIX ZONATA (ULVOPHYCEAE)1
Authors: Graham James M. , Kranzfelder James A. , Auer Martin T. 
Published: August 2010

ABSTRACT Ulothrix zonata (Weber and Mohr) Kütz. is an unbranched filamentous green alga found in rocky littoral areas of many northern lakes. Field observations of its seasonal and spatial distribution indicated that it should have a low temperature and a high irradiance optimum for net photosynthesis, and at temperatures above 10°C it should show an increasingly unfavorable energy balance. Measurements of net photosynthesis and respiration were made at 56 combinations of light and temperature. Optimum conditions were 5°C and 1100 μE·m−2·s−1 at which net photosynthesis was 16.8 mg O2·g−1·h−1. As temperature increased above 5° C optimum irradiance decreased to 125 μE·m−2·s−1 at 30°C. Respiration rates increased with both temperature and prior irradiance. Light‐enhanced respiration rates were significantly greater than dark respiration rates following irradiance exposures of 125 μE·m−2·s−1 or greater. Polynomials were fitted to the data to generate response surfaces. Polynomial equations represent statistical models which can accurately predict photosynthesis and respiration for inclusion in ecosystem models.
ANNUAL PRODUCTIVITY AND EXTRACELLULAR RELEASE OF DISSOLVED ORGANIC COMPOUNDS BY THE EPIBENTHIC ALGAL COMMUNITY OF A BRACKISH MARSH1
Authors: Hall Shelly L. , Fisher Frank M. 
Published: August 2010

ABSTRACTAnnual productivity and excretion of organic compounds by epibenthic algae in a coastal Texas marsh were investigated using 14C techniques. Over the course of two years, productivity and extracellular release were measured bimonthly to assess the environmental factors affecting seasonal patterns. Annual productivity was estimated to be 71 gc·m−2, approximately 10% of the estimated net aerial productivity of the grass canopy in this area. The percentage of photoassimilated carbon released was fairly constant, and the rate of excretion appeared to be primarily dependent upon the rate of carbon fixation. Greater rates of release were observed with high salinity, low soil moisture conditions. It was estimated that up to 10% of the DOC in adjacent tidal creek water could be produced by this community and could represent an important source of nutrients for consumers in the system.
PHOTOSYNTHETIC ACTION SPECTRUM OF THE COCCOLITHOPHORID, EMILIANIA HUXLEYI (HAPTOPHYCEAE): 19′ HEXANOYLOXYFUCOXANTHIN AS ANTENNA PIGMENT1,2
Authors: Haxo Francis T. 
Published: August 2010

ABSTRACTAction spectra for modulated O2 production were compared with cell absorbance in Emiliania huxleyi (Lohm.) Hay and Mohler, a marine coccolithophorid in which 19′ hexanoytoxyfucoxanthin is the major carotenoid of the photosynthetic apparatus, Photosynthetic effectiveness (action/absorption) was high throughout the spectral interval, 500–550 nm, where 19′ hexanoyloxyfucoxanthin accounted for most of the photon capture. 19′ hexanoyloxyfucoxanthin is thus considered to be an efficient antenna pigment for photosynthesis and to be preferentially associated with photosystem II. It may be a quantitatively significant light harvesting pigment for some algae of the marine environment.
IN SITU UPTAKE KINETICS OF AMMONIUM AND PHOSPHATE AND CHEMICAL COMPOSITION OF THE RED SEAWEED GRACILARIA TIKVAHIAE1
Authors: Friedlander Michael , Dawes Clinton J. 
Published: August 2010

ABSTRACTThe uptake kinetics of ammonium and phosphate by Gracilaria tikvahiae McLachlan were studied under field conditions. Seaweeds, pulse fed once a week for 6 h over a 4‐week period, had maximum uptake rates of 19 μmol·g fwt−1·h−1 for ammonium and 0.28 μmol·g fwt−1·h−1 for phosphate. For both nutrients there was a positive linear correlation between uptake rate (v) and concentration (S) over the entire range of concentration tested. In a nutrient depletion experiment, the phosphate uptake curve determined over a wide range of concentrations consisted of two stages of saturation at low concentrations, and a linear phase at high concentrations. Ash free dry weight, chlorophyll a, phycoerythrin, and protein content were higher in pulse fed plants than in control plants receiving no nutrient additions, while the reverse held true for carbohydrate contents and the C/N ratios. The C/N ratio inversely correlated with ammonium and phosphate uptake rate as well as protein and phycoerythrin content, and positively with carbohydrate content.
FINE STRUCTURE OF THE IMMOBILE DINOCOCCALEANCYSTODINIUM BATAVIENSE(DINOPHYCEAE)1
Authors: Timpano Peter , Pfiester Lois A. 
Published: August 2010

ABSTRACTThe fine structure of the immobile stage ofC. batavienseKlebs reveals several features which may prove helpful in understanding the parameters of the order Phytodinales. The cell covering is confluent with no thecal plates. Neither external membranes nor pores are present. The pusule tubules and collecting chamber have no external opening via flagellar pores or canals. The cell is highly vacuolate with a tonoplast‐like membrane delimiting the pusule system from the cytoplasm in the interior of the cell. Polyvesicular bodies, mitochondria with enlarged matrices containing electron‐dense bodies, vesicles which may contain flagellar hairs, crystals, and large accumulation bodies are present.
OBSERVATIONS ON THE HABIT, MORPHOLOGY AND ULTRASTRUCTURE OF CEPHALEUROS PARASITICUS (CHLOROPHYTA) AND A COMPARISON WITH C. VIRESCENS1
Authors: Chapman Russell L. , Henk Margaret C. 
Published: August 2010

ABSTRACT Cephaleuros parasiticus Karsten, an endophyte of Magnolia grandiflora L. has been examined with light, and scanning and transmission electron microscopy. The discoid thalli are composed of filaments which ramify throughout the leaf tissues beneath the epidermis. Algal filaments do not penetrate host cells, but do produce black leaf spots which have been mistaken for those caused by the fungus Glomerella cingulate (Ston.) Spauld. and Schrenk. Two distinct thallus types occur, often simultaneously on a single leaf. One bears clusters of zoosporangiate branches which seasonally emerge through the ventral (and rarely, dorsal) surface of the leaf. In contrast, the other thallus type bears gametangia which break through the dorsal leaf surface. Zoosporangia and gametangia have never been found on the same thallus. The zoosporangia are smaller than, but almost identical in shape to, those of C. virescens Kunze. Simple plasmodesmata are present in crosswalls and acetolysis indicates that little or no sporopollenin is present in the cell walls. The ultrastructure of biflagellate gametes and quadriflagellate zoospores is virtually indistinguishable from that reported for C. virescens and similar to that reported for Phycopeltis and Trentepohlia. In both gametes and zoospores there are keeled flagella, overlapping and parallel basal bodies, two 3‐layered multilayered structures with microtubular splines, and two medial compound microtubular roots. Pyrenoids, eyespots, flagellar and body scales, striated roots (or rhizoplasts), and distal bands are absent. Two presumptive mating structures are present in each biflagellate gamete, and flagellar collars occur in both types of motile cells. The extreme similarity in motile cell ultrastructure revealed in this interspecific comparison parallels that similarity revealed in intergeneric comparisons.
DEVELOPMENT OF THE FLAGELLAR APPARATUS AND FLAGELLAR POSITION IN THE COLONIAL GREEN ALGA PLATYDORINA CAUDATA (CHLOROPHYCEAE)1
Authors: Taylor Mark G. , Floyd Gary L. , Hoops Harold J. 
Published: August 2010

ABSTRACTThe ultrastructure of the flagellar apparatus in pre‐inversion and inversion stages of Platydorina resembles that of Chlamydomonas in having 180° rotational symmetry and clockwise absolute orientation. Basal bodies are in a “V” configuration and connected by one distal and two proximal fibers. Alternating two‐ and four‐membered microtubular rootlets are cruciately arranged. During maturation, the basal bodies rotate and separate, and 180° rotational symmetry is lost. Simultaneously, each proximal fiber detaches from one of the functional basal bodies, and the distal fiber detaches from both. The mature apparatus has widely separated and nearly parallel basal bodies. Flagellar orientation in Platydorina is completed just after inversion and a flattening of the colony called intercalation, resulting in the pairs of flagella of neighboring cells extending from the colony in opposite directions in an alternating fashion. Flagellar orientation and separated basal bodies minimize the interference between the flagella of neighboring cells. Basal bodies and rootlets of the two intercalated halves of a colony rotate, resulting in the effective strokes of the flagella of every cell being towards the colonial posterior. The flagella of each cell beat with an effective stroke in the direction of the two inner rootlets. The flagella have an asymmetrical ciliary type beat. The rotated, separated, and parallel basal bodies, together with the nearly parallel rootlets probably are adaptations for movement of this colonial volvocalean alga. The flagellar apparatus in immature stages of Platydorina lends support to the suggestion that the alga has evolved from a Chlamydomonas‐like ancestor.
THE RESERVOIR CYTOSKELETON AND A POSSIBLE CYTOSTOMAL HOMOLOGUE IN COLACIUM (EUGLENOPHYCEAE)1
Authors: Willey Ruth L. , Wibel Ronald G. 
Published: August 2010

ABSTRACTThe reservoir cytoskeleton of Colacium Ehrenberg is formed of three bands of microtubules. The microtubules of the dorsal band (DMT) become doublets and are continuous with the longitudinal microtubules of the canal and, therefore, of the pellicle. A band of para‐reservoir microtubules (PMT) acts as a linkage between the edges of the dorsal band at the formation of the canal. The third band of microtubules (MTR), more ventral, branches away from the reservoir‐canal transition region and forms a supportive band for a pocket formed from the reservoir membrane. The outer part of the pocket membrane is closely invested with a fibrillar mesh. The pocket of Colacium, a green euglenoid, resembles structurally the cytopharynx of the colorless phagotrophic euglenoids, Isonema papillatum and the bodonid flagellates. The homologies support the hypothesis of euglenoid derivation from the kinetoplastid flagellates.
INDIAN OCEAN NANNOPLANKTON. II. HOLOCOCCOLITHOPHORIDS (CALYPTROSPHAERACEAE, PRYMNESIOPHYCEAE) WITH A REVIEW OF EXTANT GENERA1
Authors: Norris Richard E. 
Published: August 2010

ABSTRACTHolococcolithophorids, pyrmnesiophytes having only one type of calcareous element in their coccoliths, are delicate and not commonly recorded in recent and fossil marine floras. There are few records of these organisms from the Indian Ocean and 26 species from there are included in this report. Although the group, generally assigned to a single family, the Calyptrosphaeraceae, may contain species that are part of the life history of heterococcolith‐bearing cells in other stages, so little is known of this aspect of their biology that one must continue, at the present time, to treat them as independent taxonomic entities. A key is provided for the known holococcolithophorid genera. A new genus, Gliscolithus, and three new species, Gliscolithus amitakarenae, Calyptrosphaera heimdalae, and Helladosphaera pienaarii are described. The following new combinations are proposed: Calyptrolithina fragaria (Kamptner) comb. nov., Calyptrolithina gaarderae (Borsetti et Cati) comb. nov., Calyptrolithina isselii (Borsetti et Cati) comb. nov., Calyptrolithina lafourcadii (Lecal) comb. nov., Calyptrolithina magnaghii (Borsetti et Cati) comb. nov., Calyptrolithina multipora (Gaarder) comb. nov., Calyptrolithina porritectum (Heimdal) comb. nov., Calyptrolithina wettsteinii (Kamptner) comb. nov., Calyptrolithophora catillifera (Kamptner) comb. nov., Calyptrolithophora galea (Lecal‐Schlauder) comb. nov., Dactylethra pirus (Kamptner) comb. nov., Helladosphaera arethusae (Kamptner) comb. nov., Helladosphaera gracilis (Kamptner) comb. nov., Homozygosphaera strigilis (Gaarder) comb. nov. and Syracolithus schilleri (Kamptner) comb. nov. The new combination in the genus Dactylethra Gartner for the first time brings an extant species into this genus that formerly contained only fossil species. It is pointed out that the enlarged zygoliths in stomatal areas of Corisphaera and the helladoliths in stomatal regions of Helladosphaera have intergrading types and are not distinctive enough characteristics to separate these genera.
PHYSIOLOGICAL AND ENVIRONMENTAL CONTROL OF GERMINATION INSCRIPPSIELLA TROCHOIDEA(DINOPHYCEAE) RESTING CYSTS1
Authors: Binder Brian J. , Anderson Donald M. 
Published: August 2010

ABSTRACTThe effects of aging, temperature, and growth medium on germination in culture‐produced resting cysts of the marine dinoflagellateScrippsiella trochoidea(Stein) Loeblich ore examined. Cysts undergo a mandatory period of dormancy lasting approximately 25 days, during which germination does not occur. The duration of this period is not affected by temperature. Once the dormancy period is completed, germination is regulated by external factors. Cysts germinate optimally in nutrient replete medium at temperatures greater than approximately 14° C. At lower temperatures or in nutrient‐depleted media germination rate is dramatically slowed, although the final germination frequency appears unchanged. The large Q10of this temperature effect (ca. 11) suggests that the reduction in germination rate at lower temperatures is not merely the reflection of generally reduced metabolic rates, but rather the result of a temperature response specific to germination. At the highest temperatures tested (22–25° C), germination rate remains maximal although vegetative growth is greatly reduced. A shift in temperature or nutrient conditions, per se, is not necessary for germination. The relatively short dormancy period combined with the absence of a requirement for a dramatic shift in environmental conditions could facilitate rapid cycling between resting and vegetative stages in naturalS. trochoideapopulations. At the same time, the dramatic reduction in germination rate at low temperatures would permit cysts of this species to serve as overwintering cells as well.
COMPARATIVE ULTRASTRUCTURE OF THREE SPECIES OF CHLOROSARCINA (CHLOROSARCINACEAE, CHLOROPHYTA) 1,2
Authors: Deason Temd R. , Floyd Gary L. 
Published: August 2010

ABSTRACTUltrastructural studies revealed that Chlorosarcina stigmatica Deason differs from C. brevispinosa and C. longispinosa Chantanachat and Bold because the vegetative cell possess a pyrenoid, and the zoospores have chlorophycean characteristics. Zoospores of the latter species exhibit pleurastrophycean characteristics including counterclockwise absolute orientation of the flagellar apparatus components. Nuclear division in C. longispinosa, like that of Friedmannia israelensis Chantanachat and Bold, is metacentric. It is suggested that a new genus, Desmotetra, be erected for Chlorosarcina stigmatica, and that it, along with Chlorosarcinopsis Herndon, be placed in the Chlorococcales, Chlorophyceae. Chlorosarcina brevispinosa and C. longispinosa belong in the Pleurastrales, Pleurastrophyceae.
The Xanthomonas campestris pv. vesicatoria citH gene is expressed early in the infection process of tomato and is positively regulated by the TctDE two‐component regulatory system
Authors: TAMIR‐ARIEL DAFNA , ROSENBERG TALLY , BURDMAN SAUL 
Published: August 2010

SUMMARY Xanthomonas campestris pv. vesicatoria (Xcv) is the causal agent of bacterial spot disease of tomato and pepper. Previously, we have reported the adaptation of a recombinase‐ or resolvase‐based in vivo expression technology (RIVET) approach to identify Xcv genes that are specifically induced during its interaction with tomato. Analysis of some of these genes revealed that a citH (citrate transporter) homologous gene contributes to Xcv virulence on tomato. Here, we demonstrate that the citH product indeed facilitates citrate uptake by showing the following: citH is specifically needed for Xcv growth in citrate, but not in other carbon sources; the citH promoter is specifically induced by citrate; and the concentration of citrate from tomato leaf apoplast is considerably reduced following growth of the wild‐type and a citH‐complemented strain, but not the citH mutant. We also show that, in the Xcv–tomato interaction, the promoter activity of the citH gene is induced as early as 2.5 h after Xcv is syringe infiltrated into tomato leaves, and continues to be active for at least 96 h after inoculation. We identified an operon containing a two‐component regulatory system homologous to tctD/tctE influencing citH expression in Xcv, as well as its heterologous expression in Escherichia coli. The expression of hrp genes does not seem to be affected in the citH mutant, and this mutant cannot be complemented for growth in planta when co‐inoculated with the wild‐type strain, indicating that citrate uptake in the apoplast is important for the virulence of Xcv.
Population growth of red lechwe, Kobus leche leche Gray, in the Busanga Plain, Zambia
Authors: GRIMSDELL J. J. R. , BELL R. H. V. 
Published: August 2010

SummaryAn isolated population of red lechwe living in the Busanga Plain, Zambia, has been protected from human hunting since 1948. Probably as a result the population has increased, as indicated by reliable census data. From 1956 to 1972 this increase has very closely fitted an exponential rate; the calculated value of the infinitesimal rate of population increase (r) is 0–131, and the finite rate of increase is 14‐0% per year. This exponential phase is considered to represent a segment of a logistic curve.
Balance is the challenge – The impact of mitochondrial dynamics in Parkinson’s disease
Authors: Burbulla Lena F. , Krebiehl Guido , Krüger Rejko 
Published: August 2010

Eur J Clin Invest 2010; 40 (11): 1048–1060AbstractImpaired mitochondrial function has been implicated in neurodegeneration in Parkinson’s disease (PD) based on biochemical and pathoanatomical studies in brains of PD patients. This observation was further substantiated by the identification of exogenic toxins, i.e. complex I inhibitors that directly affect mitochondrial energy metabolism and cause Parkinsonism in humans and various animal models. Recently, insights into the underlying molecular signalling pathways leading to alterations in mitochondrial homeostasis were gained based on the functional characterization of mitoprotective genes identified in rare forms of inherited PD. Using in vitro and in vivo loss of function models of the Parkin, PINK1, DJ‐1 and Omi/HtrA2 gene, the emerging field of mitochondrial dynamics in PD was established as being critical for the maintenance of mitochondrial function in neurons. This underscored the concept that mitochondria are highly dynamic organelles, which are tightly regulated to continuously adapt shape to functional and anatomical requirements during axonal transport, synaptic signalling, organelle degradation and cellular energy supply. The dissection of pathways involved in mitochondrial quality control clearly established the PINK1/Parkin‐pathway in the clearance of dysfunctional mitochondria by autophagy and hints to a complex interplay between PD‐associated proteins acting at the mitochondrial interface. The elucidation of this mitoprotective signalling network may help to define novel therapeutic targets for PD via molecular modelling of mitochondria and/or pharmacological modulation of mitochondrial dynamics.
Association of breast carcinoma and multiple intraductal papillomas: an histological and immunohistochemical investigation
Authors: PAPOTTI M. , GUGLIOTTA P. , GHIRINGHELLO B. , BUSSOLATI G. 
Published: August 2010

To identify histological preneoplastic lesions and early neoplastic foci, a histological and immunohistochemical study has been conducted on a series of 18 cases with the rare association of multiple intraductal papillomas and in situ breast carcinoma. The pathological and clinical data of these cases have been collated.A close anatomical and spatial association between the benign papillomas and areas of in situ carcinoma (mostly of the cribriform type) was a frequent finding.In agreement with the results of our previous investigations, cytoplasmic CEA has been found to be a marker of intraductal carcinomas, while staining for actin has been found useful to identify the myoepithelial cells present in benign papillomas as opposed to carcinomas. The immunohistochemical procedures for these two markers have been conducted on parallel sections; alternatively, an immunoperoxidase/immuno‐galactosidase sequence has been applied on the same section.The results indicate that, in cases with multiple papillomas, CEA‐positive, myoepithelial cell‐free carcinomatous areas can be anatomically associated with and even present inside the benign‐looking papillary lesions.These findings can be interpreted as evidence of a malignant transformation of intraductal papillomas, or, less likely, of their ‘cancerization’ by ductal carcinoma.
Pleomorphic xanthoastrocytoma: a comparative pathological study between conventional and anaplastic types
Authors: Hirose T , Ishizawa K , Sugiyama K , Kageji T , Ueki K , Kannuki S 
Published: August 2010

Aims:  To facilitate the understanding and correct diagnosis of the anaplastic variant of pleomorphic xanthoastrocytoma (PXA).Methods and results:  Twelve cases of PXA were divided into six conventional and six anaplastic types. Three anaplastic PXAs developed in recurrent tumours and three occurred as the primary tumour. Anaplastic PXAs were microscopically characterized by monotonous proliferation of atypical cells, increased mitotic activity, necrosis and microvascular proliferation. Characteristic features of conventional PXA are also variously included in all anaplastic PXAs. No remarkable differences were detected in the immunohistochemical profiles including the neuronal phenotype between the conventional and anaplastic types. Ki67 labelling indices of the anaplastic type were significantly higher than those of the conventional type, whereas p53 showed no difference. Immunohistochemical and fluorescence in situ hybridization analyses on epidermal growth factor receptor did not demonstrate overexpression or gene amplification.Conclusions:  The anaplastic PXA, which occurs de novo or through recurrence, should be distinguished from glioblastoma by identifying the salient microscopic features of conventional PXA even in the anaplastic areas; and by demonstrating the expression of neuronal markers, in that the former is expected to have longer survival.