bluuebunny/crossref_metadata_2025_split huggingface dataset:
BIDDULPHIOID DIATOMS: RESTING SPORES IN ANTARCTIC EUCAMPIA AND ODONTELLA1
Authors: Hoban Michael A. , Fryxell Greta A. , Buck Kurt R. 
Published: August 2007

ABSTRACTSome antarctic diatoms form resting spores, differing morphologically and probably physiologically from vegetative cells. Differences in the type of resting stages became apparent while examining three species of endemic Antarctic diatoms (Bacillariophyceae, Centrales): Eucampia balaustium Castracane, Odontella weissflogii (Janisch) Grunow, and O. litigiosa (van Heurck) Hoban, comb. nov. Eucampia balaustium usually forms two resting spores per vegetative cell with apparently one residual body and rudimentary valve per resting spore. Odontella weissflogii produces one endogenous resting spore per vegetative cell with at least one, presumably two, residual bodies per resting spore. Through an indeterminate number of divisions, Odontella litigiosa produces a heavily spined morphotype that may function as a resting spore. Odontella litigiosa is transferred from the genus Biddulphia to Odontella C. A. Agardh. The resting spores of all three species have girdle bands. Since resting spores may evolve at different rates than vegetative cells, morphological similarities between the resting spores and the vegetative cells of species in this study and the vegetative cells of species in related families and genera may indicate taxonomic relationships and be of value in formulating phylogenetic schemes.
OBSERVATIONS ON THE SURVIVAL AND GERMINATION OF RESTING SPORES OF THREE CHAETOCEROS (BACILLARIOPHYCEAE) SPECIES1,2
Authors: Hollibaugh J. T. , Seibert D. L. R. , Thomas W. H. 
Published: August 2007

ABSTRACTResting spores (hypnospores) of Chaetoceros diadema (Ehrenberg) Gran, Chaetoceros vanheurckii Gran, and Chaetoceros didymus Ehrenberg were collected from a large plastic enclosure moored in Saanich Inlet, B.C., Canada. The effects of combinations of temperature and irradiance on the germination of these resting spores were investigated. Nutrient uptake, carbon fixation, and changes in the photosynthetic capacity of the germinating spores were also examined. Resting spores germinated optimally at combinations of temperature and irradiance similar to those in the environment during sporulation. They did not germinate at irradiances 1.3 μEin m−2 s−1 or temperatures >25.3° C. Nitrate, phosphate and silicate were taken up after the resting spores had germinated and resumed vegetative growth. Chlorophyll a fluorescence in vivo, and the DCMU‐induced increase in in vivo fluorescence also increased after the resting spores had germinated. Resting spores began to fix carbon as soon as they were placed in light. Spores remained viable for at least 645 d. The length of time between first exposure to light and germination did not change during this period; however, the percentage of viable resting spores decreased markedly. None of the Chaetoceros spores germinated after 737 d of storage at 2–4° C in darkness.
PALMELLOPSIS MURALIS SP. NOV. (CHLOROPHYCEAE, TETRASPORALES, PALMELLACEAE)1
Authors: Bold Harold C. , Slocum Robert D. , King Joe M. , MacEntee Frank J. 
Published: August 2007

ABSTRACTA new member of the chlorophycean, tetrasporalean genus Palmellopsis Korschikov (1953), Palmellopsis muralis Bold and King, is described from limestone in Austin, Texas, U.S.A. Certain details of ultrastructural organization are included.
MORPHOLOGY AND TAXONOMY OF HIMANTOTHALLUS (INCLUDING PHAEOGLOSSUM AND PHYLLOGIGAS), AN ANTARCTIC MEMBER OF THE DESMARESTIALES (PHAEOPHYCEAE)1
Authors: Moe Richard L. , Silva Paul C. 
Published: August 2007

ABSTRACTThe sporophyte of Himantothallus develops according to a closed pattern in which the number and position of the blades is determined by the location of trichothallic meristems in a filamentous germling. Expansion of the miniature juvenile to the massive adult thallus is accomplished by diffuse secondary growth and involves a change from filamentous rhizoids to a hapteroid holdfast, flattening of the stipe, and enormous increases in length, breadth, and thickness of both stipe and blade. The axis usually bears 1–8 lateral blades, often paired, and terminates in a flattened stub. Phaeoglossum is interpreted as a growth form of Himantothallus in which a terminal blade develops to the exclusion of lateral blades, the latter being represented by a single spine. Phyllogigas clearly falls within the morphological spectrum of Himantothallus, the lack of twisting being related to physical factors in the environment.Sporangia, interspersed with an equal or somewhat larger number of two‐celled paraphyses, are borne in slightly elevated sori scattered over both surfaces of the blade. Zoospore germination was not observed, nor were gametophytes, either in culture or in the field.Haptera apparently originate from the meristoderm in the lower part of the maturing stipe and lack a filamentous medulla. The mature stipe and the mature blade are anatomically similar, being composed of a superficial meristoderm, a cortex of parenchyma‐like cells, and a filamentous medulla. The meristoderm is usually a single layer of plastid‐containing cells that divide anticlinally to accommodate (or effect) expansion and periclinally to produce cortical tissue inward. Cortical cells are in radial files and increase in diameter towards the interior. They usually are densely packed with physodes. The medulla is uniquely distinguished by the presence of sheathed trumpet hyphae. Cells of the trumpet hyphae have perforate end walls with callose deposits and probably function in conduction as do the sieve filaments in Laminariales. Sheathing cells are filled with plastids. Sheathing filaments form connections among themselves and with nearby unsheathed filaments. The sheathed trumpet hyphae and their matrix of unsheathed filaments form a plexus, which in the mature blade is flattened and may be stripped intact from the other tissues.Development of the embryonic sporophyte is very similar to that in Desmarestia, as is the anatomy of the adult thallus and the sporangia. From these considerations, Himantothallus is assigned to the Desmarestiaceae (Desmarestiales).
QUANTITATIVE DIFFERENCES BETWEEN BENTHIC ALGAL COMMUNITIES ALONG A DEPTH GRADIENT IN LAKE MICHIGAN1,2
Authors: Stevenson R. Jan , Stoermer Eugene F. 
Published: August 2007

ABSTRACTThis study analyzes the impact of conditions associated with depth upon benthic algal communities in Lake Michigan. Diatom abundance was greater at 9.1 and 14.6 m depths than 6.5, 22.6 and 27.4 m. Shallow (6.5 m), mid‐depth (9.1 and 14.6 m) and deep (22.6 and 27.4 m) zones were distinguishable on the basis of community composition, structure and abundance. Dominance of benthic species, high diversity and low abundance in shallow communities probably resulted from substantial substrate disturbance by wave action in this productive zone. Dominance of benthic species, high diversity and high abundance characterized mid‐depth communities where less wave disturbance enabled algal accumulation. Preponderance of living planktonic taxa, low diversity and low abundance delineated deep communities where planktonic algae accumulated and low light levels reduced growth of benthic species.
MORPHOLOGICAL CHANGES IN TOXIC AND NON‐TOXIC MICROCYSTIS ISOLATES AT DIFFERENT IRRADIANCE LEVELS1
Authors: Krüger G. H. J. , Eloff J. N. , Pretorius J. A. 
Published: August 2007

ABSTRACTLight intensity (4.5–40.0 μEin m−2 s−1) and culture age had a pronounced effect on cell size and size range of a non‐toxic axenic Microcystis isolate. The rate of cell volume increase (μm3 d−1) was 1.03 × light intensity (μEin m−2 s−1) – 6.49. Average cell volume varied from 33 to 119 μm3, cells at higher light intensities being larger and having a larger size range. The effects on a toxic axenic Microcystis isolate were similar but less pronounced. Average cell volume ranged from 21–74 μm3. In general, cell size and especially size variability appear to be sensitive indicators of physiological state, with cells under stress conditions being larger and associated with a larger size range. The wide range of cell diameters observed at different irradiance levels (3.4–7.2 μm for the non‐toxic and 1.8–6.4 μm for the toxic isolate), makes questionable the use of cell size as a taxonomic character without careful consideration of environmental conditions.
SEASONALITY OF MICROBIAL FOULING ON ASCOPHYLLUM NODOSUM (L.) LEJOL., FUCUS VESICULOSUS L., POLYSIPHONIA LANOSA (L.) TANDY AND CHONDRUS CRISPUS STACKH1
Authors: Sieburth John McN. , Tootle J. Lawton 
Published: August 2007

ABSTRACTThe nature and seasonal extent of microbial fouling on Ascophyllum nodosum (L.) LeJol., Fucus vesiculosus L., Polysiphonia lanosa (L.) Tandy and Chondrus crispus Stackh. were observed by scanning electron microscopy. Bacterial filaments and smaller rod and coccoid forms dominated the fouling communities on all species, with pennate diatoms constituting a minor component in contrast to results with plastic substrates on which pennate diatoms dominated and preceded bacterial colonization. The total percent microbial coverage on the surfaces of all four seaweed species was determined by monthly stereological analyses of representative composite micrographs. These showed a simultaneous decline between April and May which could represent the die‐off of the cold water bacterial flora when water temperature increased past the threshold for obligate psychrophiles. Microbial colonization patterns were directly correlated (P = 0.005) with maximum coverage in April and November–December and reduced levels from May to October. Significant inverse (P < 0.041) correlations between total percent coverage and water temperature indicate distinct seasonal cycles, however, the patterns of dominance by filamentous bacteria and rod and coccoid forms were markedly different. Total coverage patterns of both rhodophytes showed no apparent seasonal cycle and were not related to water temperature. Rod and coccoid bacteria were apparently suppressed year round on P. lanosa relative to the other species. These interspecific differences in seasonal fouling patterns are discussed in light of possible modes of regulation, especially algal antibiosis.
FREEZE‐FRACTURED CHLOROPLAST MEMBRANES OF GONYAULAX POLYEDRA (PYRROPHYTA)1
Authors: Sweeney Beatrice M. 
Published: August 2007

ABSTRACTThe chloroplast membranes of Gonyaulax polyedra Stein were studied in replicas of rapidly frozen and fractured cells. The thylakoid EFs face lacked the large 15–16 nm particles characteristic of plants with the light‐harvesting chlorophyll a/b protein, presumably because the principal light‐harvesting protein of Gonyaulax is the small water‐soluble peridinin‐chlorophyll‐protein and the chlorophyll a/b protein is absent. As in other plants, the EFs thylakoid fracture face carried more particles (4 ×) than EFuface. The PF faces of the thylakoid showed twice as many particles as did the EFs faces. No circadian differences in the number or size of thylakoid membrane particles could be detected. Three membranes comprise the chloroplast envelope in Gonyaulax. They could be clearly differentiated in freeze‐fractured cells. The middle envelope membrane carried many fewer particles on both the EF and PF faces than did the other two envelope membranes. The PF faces of both the outer and inner envelope membranes showed more particles than the EF faces, as do many other membranes which have been examined.
SOURCE‐SINK RELATIONSHIPS IN THE BLADE OF ALARIA ESCULENTA (LAMINARIALES, PHAEOPHYCEAE)1
Authors: Buggeln Richard G. 
Published: August 2007

ABSTRACTThe translocation of 14C‐labelled photoassimilate was studied in blades of the kelp, Alaria esculenta (L.) Grev., which had been surgically modified to produce source and sink regions of various sizes. Thirty cm above the blade base a 2.5 cm dia. section of the blade received a 1 h pulse of H14CO3−. Efflux of 14C‐labelled photoassimilate from this “source disc” was monitored over the next 8 days using a Geiger‐Müller detector probe. Accumulation of 14C‐labelled solutes by a “sink disc” of similar diameter, 20 cm below the source disc, was also monitored. Rate of l4C efflux from the source disc was governed by two factors: (1) total sink size and (2) feed‐back from competing sources. In the latter case, source export was depressed if the portion of the blade, just distal to the source disc, was present. While the initial 14C influx rate into the sink disc was greater when competing sinks were present, the total accumulation of 14C‐photoassimilates was 2–3 times higher in the sink disc when competing sources were not present. Basipetal translocation velocity (1.3–1.7 cm h−1) was unaffected by competing sources and sinks.
BROMINE IN THE CUTICLE OF POLYSIPHONIA NIGRESCENS: LOCALIZATION AND CONTENT1
Authors: Pedersén Marianne E. E. , Roomans Godfried M. , Hofsten Angelica v. 
Published: August 2007

ABSTRACTThe cuticles and chloroplasts of young and old fronds of Polysiphonia nigrescens (Huds.) Grev. were analysed by quantitative X‐ray microanalysis for their content of bromine. Cuticles of old fronds contained 1.7 ± 0.14% bromine while those of young ones contained only 0.94 ± 0.22% bromine. The bromine content of the chloroplasts showed considerable variations between individual chloroplasts, but was found not to increase with age. Young fronds contained four separate layers in the cuticle when observed under the electron microscope. In the old fronds three of these layers disappeared while the remaining one became thick and very electron dense.
HEAVY METALS AND MARINE PHYTOPLANKTON: CORRELATION OF TOXICITY AND SULFHYDRYL‐BINDING1,2
Authors: Fisher Nicholas S. , Jones Gary J. 
Published: August 2007

ABSTRACTIn a study of sublethal effects of metals on growth of the marine diatom Asterionella japonica Cleve, the relative toxicities of Hg, Cu, Zn, Pb, Cd, and Mn are shown to be correlated (r = 0.961) with the solubility products of the corresponding metal sulfides. The results, together with findings elsewhere, suggest a common action for these heavy metals, with toxicity deriving from metal binding to sulfhydryl‐containing compounds in the cell.
The Analytic/Synthetic Distinction
Authors: Russell Gillian 
Published: August 2007

AbstractThe distinction between analytic and synthetic truths has played a major role in the history of philosophy, but it was challenged by Quine and others in the 20th century, and the distinction's coherence and importance is now controversial. This article traces the distinction's historical development and summarises the major arguments against it. Some post‐Quinian accounts are discussed, and the article closes with a list of five challenges which any contemporary account of the distinction ought to meet.
Temporal Parts
Authors: McGrath Matthew 
Published: August 2007

AbstractThis article discusses recent work in metaphysics on temporal parts. After a short introduction introducing the notion of a temporal part, we examine several well‐known arguments for the view that ordinary material objects such as tables, trees, and persons have temporal parts: (1) positing temporal parts makes it possible to solve puzzles of coincidence (e.g., the statue/lump puzzle); (2) positing temporal parts makes it possible to solve the problem of intrinsic change over time; and (3) the existence of temporal parts can be demonstrated based on considerations about vagueness in composition. We conclude by examining briefly a recent argument that the dispute over whether there are temporal parts is merely verbal.
Hume's Distinction between Philosophical Anatomy and Painting
Authors: Abramson Kate 
Published: August 2007

AbstractAlthough the implications of Hume's distinction between philosophical ‘anatomy’ and ‘painting’ have been the subject of lively scholarly debates, it is a puzzling fact that the details of the distinction itself have largely been a matter of interpretive presumption rather than debate. This would be unproblematic if Hume's views about these ‘two species of philosophy’ were obvious, or if there were a rich standard interpretation of the distinction that we had little reason to doubt. But a careful review of the literature shows neither to be the case. We are far from scholarly consensus about Hume's vision of philosophical anatomy and painting, and what unity there is rests on extremely unsteady ground and leaves important questions unanswered. In this article, my aim is three‐fold: first, to show that the appearance of well‐grounded scholarly unity about Hume's distinction is illusory; second, to dispose of those misinterpretations of Hume's distinction that are sufficiently at odds with the text that they can be demonstrated to be false in this context; and third, to explore in sufficient detail the numerous questions one might raise about the content of Hume's distinction so that the stage might at last be properly set for a truly full account of Hume's distinction between philosophical anatomy and painting.
Serodiagnosis of Anthroponotic Cutaneous Leishmaniasis (ACL) Caused byLeishmania tropicain Sanliurfa Province, Turkey, Where ACL Is Highly Endemic
Authors: Zeyrek Fadile Yildiz , Korkmaz Metin , Özbel Yusuf 
Published: August 2007

ABSTRACTIn this study, we aimed to evaluate the validity of the conventional enzyme-linked immunosorbent assay (ELISA) and the Western blotting test for the diagnosis of anthroponotic cutaneous leishmaniasis (ACL) using serum samples obtained from 51 patients with parasitologically proven nontreated CL (NonT-CL patients) and 62 patients under treatment for CL (UT-CL patients). Additionally, 29 serum samples obtained from patients with parasitologically and serologically proven visceral leishmaniasis (VL) were also used as positive controls, and serum samples from 43 blood donors were used as negative controls. All sera were diluted to the same dilution (1/100).Leishmania infantumMON-1 was used as the antigen in the conventional ELISA. The sera of 27 (93.1%) of 29 VL patients were seropositive by ELISA, while the sera of 40 (78.4%) of 51 NonT-CL patients and 43 (69.3%) of 62 UT-CL patients were seropositive by the conventional ELISA. The absorbance values of the CL patients' sera were significantly lower than the absorbance values of the VL patients' sera. Bands between 15 and 118 kDa were detected in two groups of CL patients. Among all bands, the 63-kDa band was found to be more sensitive (88.5%). When we evaluated the Western blotting results for the presence of at least one of the diagnostic antigenic bands, the sensitivity was calculated to be 99.1%. By using serological tests, a measurable antibody response was detected in most of the CL patients in Sanliurfa, Turkey. It is also noted that this response can be changed according to the sizes, types, and numbers of lesions that the patient has. The Western blot test was found to be more sensitive and valid than the conventional ELISA for the serodiagnosis of ACL. In some instances, when it is very difficult to demonstrate the presence of parasites in the smears, immunodiagnosis can be a valuable alternative for the diagnosis of ACL.
Evaluation of a Single-Platform Technology for Lymphocyte Immunophenotyping
Authors: Higgins Jeanette , Hill Valerie , Lau Karen , Simpson Virginia , Roayaei Jean , Klabansky Rick , Stevens Randy A. , Metcalf Julia A. , Baseler Michael 
Published: August 2007

ABSTRACT

An accurate and reproducible CD4 count is a fundamental clinical tool for monitoring and treating human immunodeficiency virus infection and its complications. Two methods exist for calculating absolute CD4 counts: dual-platform technology (DPT) and single-platform technology (SPT). Numerous studies have documented the unacceptably wide range of variation in absolute CD4 counts between laboratories. SPT was introduced in 1996 to reduce the interlaboratory variation in absolute CD4 counts. The aim of this study was to compare DPT with the BD Biosciences Trucount method (an SPT method). Both the percentages of CD4 (
r
= 0.986;
P
= 0.0541) and the absolute CD4 counts (
r
= 0.960;
P
= 0.0001) had very good correlation between the two methods. However, poor correlation was observed for the CD8
+
RO
−
(
r
= 0.314;
P
= 0.0002), CD8
+
DR
+
(
r
= 0.666;
P
= 0.0138), CD3
+
CD38
+
(
r
= 0.8000;
P
= 0.0004), CD3
+
CD25
+
(
r
= 0.464;
P
= 0.0082), and CD4
+
CD38
+
(
r
= 0.357;
P
= 0.0127) measurements.
High Prevalence and Increased Severity of Pathology of Bovine Tuberculosis in Holsteins Compared to Zebu Breeds under Field Cattle Husbandry in Central Ethiopia
Authors: Ameni Gobena , Aseffa Abraham , Engers Howard , Young Douglas , Gordon Stephen , Hewinson Glyn , Vordermeier Martin 
Published: August 2007

ABSTRACTA comparative study on the prevalence and pathology of bovine tuberculosis (TB) was conducted on 5,424 cattle (2,578 zebus, 1,921 crosses, and 925 Holsteins), which were kept on pasture in the central highlands of Ethiopia, using a comparative intradermal tuberculin test, postmortem examination, and bacteriology. The overall prevalence of bovine TB was 13.5%; prevalence was higher in Holsteins than either zebus (22.2% versus 11.6%, χ2= 61.8;P< 0.001) or crosses (22.2% versus 11.9%, χ2= 50.7;P< 0.001). Moreover, the severity of pathology in Holsteins (mean ± standard error of the mean [SEM], 6.84 ± 0.79) was significantly higher (P= 0.018) than the severity of pathology in zebus (5.21 ± 0.30). In addition, the risk of TB in Holsteins was more than twice (odds ratio [OR] = 2.32; 95% confidence interval [CI] = 1.89, 2.85) that in zebus. Animals between 5 and 9 years of age were at higher (OR = 2.37; 95% CI = 1.80, 3.12) risk of bovine TB than those 2 years of age or below. A significant difference (χ2= 351;P< 0.001) in the occurrence of TB lesions in lymph nodes was recorded; the mesenteric lymph node (mean pathology score ± SEM, 1.95 ± 0.08) was most severely affected, followed by the retropharyngeal (0.80 ± 0.05) and caudal mediastinal (0.8 ± 0.06) lymph nodes. Fifty-six percent (n= 145) of the animals with gross TB lesions were culture positive; the lowest culture positivity was recorded in the skin lesions (27.3%) and the lesions of the mesenteric lymph node (31.5%). Both the skin test response and the postmortem findings suggested a higher susceptibility to bovine TB in Holsteins than zebus under identical field husbandry conditions (on pasture). In the light of increased numbers of Holstein cattle introduced into this area to raise milk production to satisfy the needs of Addis Ababa's growing population, these findings highlight the need for a control program in these herds.