bluuebunny/crossref_metadata_2025_split huggingface dataset:
GROWTH AND DIFFERENTIATION OF AXIAL AND LATERAL FILAMENTS IN BATRACHOSPERMUM SIRODOTII (RHODOPHYTA)1
Authors: Aghajanian John G. , Hommersand Max H. 
Published: August 2007

ABSTRACTDevelopment of the vegetative gametophyte of Batrachospermum sirodotii Skuja was examined with light and both transmission and scanning electron microscopy. Patterns of wall growth were followed using the Calcofluor White ST pulse‐chase method. Thallus structure was analysed in terms of the pattern of development of the apical, periaxial and pleuridial initials that generate the axial and whorled lateral filaments characteristic of Batrachospermum. Apical cells of axial filaments elongate initially by tip growth with the nucleus maintaining a distal position. Nuclear division is horizontal. One daughter nucleus migrates basipetally and a thin, convoluted annular septum and perforate‐occluded pit connection are then formed. Elongating axial cells subsequently extend by wall deposition at the base of the cell. Periaxial cells are initiated laterally and elongate primarily by tip growth while the nucleus remains within the axial cell. The nucleus then migrates to the boundary between the initial and the axial cell, divides, and one daughter nucleus moves into the initial and the other back into the axial cell. A slightly irregular annular septum and simple‐occluded pit connection are then formed. Pleuridial cell initials begin as terminal to subterminal protuberances on periaxial or pleuridial cells. They first extend by tip growth and later by bipolar band growth. The nucleus remains within the parent cell as the pleuridial initial expands and a narrow septal ring is formed between the two cells. It then migrates through the septal ring into the initial and divides transversely. One nucleus passes back into the parent cell and a thick, flat septum and perforate‐occluded pit connection are formed. It is concluded that the potentially indeterminate axial filaments and the determinate lateral pleuridia represent distinct developmental types in Batrachospermum.
ROLE OF GOLGI APPARATUS IN MUCILAGE PRODUCTION AND CYST FORMATION INEUGLENA GRACILIS(EUGLENOPHYCEAE)1
Authors: Triemer Richard E. 
Published: August 2007

ABSTRACTDark grown cells ofEuglena gracilisKlebs (strain Z Pringsheim) encyst when placed in minus nitrogen media for 48–72 h in the dark. The number of cisternae per dictyosome decreases from 10–20 to 6–12 during encystment. Cisternae dilate and fill with mucilage within 12–18 h after induction. The material is secreted into the reservoir and deposited onto the cell surface. The encysting cells rotate as they develop resulting in the deposition of a thick mucilaginous layer over the cell surface. The secretion product has been identified as polysaccharide with the periodic acid‐silver methenamine reaction. Mucilage has not been observed in the endoplasmic reticulum adjacent to the pellicle. The product present in the dictyosornes and on the cell surface react identically to the silver reagent.
THE DINOFLAGELLATE TRANSVERSE FLAGELLUM: THREE‐DIMENSIONAL RECONSTRUCTIONS FROM SERIAL SECTIONS1
Authors: Rees Anthony J. J. , Leedale Gordon F. 
Published: August 2007

ABSTRACTSerial sections through in situ transverse flagella of the dinoflagellate Peridinium cinctum f. irregulatum (Lindem.) Lefévre are presented. Three‐dimensional reconstructions based upon tangential and radial series show a helically coiled axoneme lying external to and distinct from an accessory strand. Hitherto undescribed vesicles within the expanded flagellar sheath are suggested to provide a decoupling effect between axoneme and strand. The flagellar axis bears two types of hair but anchoring threads between cingulum and flagellum have not been found. Functional and taxonomic implications of these observations are briefly discussed.
EFFECTS OF TEMPERATURE CONDITIONING ON DEVELOPMENT AND GERMINATION OFGONYAULAX TAMARENSIS(DINOPHYCEAE) HYPNOZYGOTES1
Authors: Anderson Donald Mark 
Published: August 2007

ABSTRACTPlankton samples from a dense bloom of the toxic red tide dinoflagellateGonyaulax tamarensisLebour were incubated in the laboratory to study the formation and development of thick‐walled, overwintering cysts. Samples, contained very few cysts, and fusing cells were seen only twice. However, thousands of elongate cysts were formed from large posteriorly biflagellated cells (presumed to be planozygotes) that comprised approximately 50% of the initial motile population. Development of these new cysts (hypnozygotes) was studied under different storage conditions. Each hypnozygote lost pigmentation and formed a thick cell wall during the first several days of storage, producing a starch‐filled cell with a yellow accumulation body. Starch reserves decreased rapidly during storage at warm (22 C) temperatures and more slowly at 5 C (with no apparent effect from light, dark, or added nutrients). Excretion of mucilaginous material was also observed. Periodic germination experiments showed that 22 C temperatures led to rapid development of the hypnozygote, with germination possible 1 mo after formation, whereas 5 C storage retarded development, with the first revivals after nearly 4 mo. Excystment was initiated only after an applied stimulus—either a temperature increase or decrease depending on the previous storage temperature. Cysts formed during the late spring in temperate waters are thus capable of excystment several months later as fall temperatures decrease; those formed in the fall take longer to mature, but are viable after six months of overwintering. Alternating spring and fall blooms seeded by germinating populations of dormant cysts are thus possible, a finding consistent with recent field observations.
NITROSOGUANIDINE AND ULTRAVIOLET LIGHT MUTAGENESIS IN EUDORINA ELEGANS (CHLOROPHYCEAE)1
Authors: Toby Anne L. , Kemp C. Lindley 
Published: August 2007

ABSTRACTReversion of an acetate requiring strain and the induction of sectored colonies are used to establish optimal conditions for nitrosoguanidine and ultraviolet light mutagenesis in Eudorina elegans Ehrenberg. Nitrosoguanidine is more effective in causing reversion of the acetate requiring strain and inducing auxotrophs. Morphogenetic mutants are more readily induced by ultraviolet light. The effectiveness of ultraviolet light as a mutagen is cell cycle dependent whereas the mutagenic action of nitrosoguanidine is not.
SUBCELLULAR LOCALIZATION OF BROMINATED SECONDARY METABOLITES IN THE RED ALGA LAURENCIA SNYDERAE1
Authors: Young David N. , Howard B. M. , Fenical W. 
Published: August 2007

ABSTRACTEnergy dispersive X‐ray fluorescence spectroscopy of thin sections of Laurencia snyderae Dawson shows bromine is concentrated in a cytoplasmic vesicle, the corps en cerise, a previously described structure characteristic of this genus. The presence of the brominated natural product β‐snyderol is shown to be related to the presence of corps en cerise in cortical cells. The presence of halogenated sesquiterpenoids in the corps en cerise of various Laurencia species is inferred from these data.
ULTRASTRUCTURE STUDIES ON SOME MASTOGLOIA SPECIES OF THE GROUP INAEQUALES (BACILLARIOPHYCEAE)1
Authors: Stephens F. Carol , Gibson Robert A. 
Published: August 2007

ABSTRACTFive species of the diatom genus Mastogloia (group Inaequales) were studied using transmitted light (TLM) and scanning electron (SEM) microscopy. Specimens for study were collected from the Indian River, Florida (salinity 16–42‰c temperature 9–34°C) as epiphytes on the sea‐grass Halodule wrightii Ashers.Both intact frustules and individual parts of frustules are described and interpreted from TLM and SEM observations of M. angulata Lewis, M. erythraea Grun., M. manokwariensis Chain., M. pusilla Grun. and M. schmidtii Heiden. Mastogloia angulata was areolate whereas the other species were punctate. Differences in internal basal valve construction are described for the five species examined. A discussion is included of the morphological characters shown by the SEM studies which led to our use of the name M. manokwariensis for a species which might otherwise be considered, as M. pusilla var. subcapitata Hust.
PHOTOMOVEMENT RESPONSES OFPORPHYRIDIUM PURPUREUM1
Authors: Hill Sylvia A. , Towill Leslie R. , Sommerfeld Milton R. 
Published: August 2007

ABSTRACTThe influence of light quality on positive phototopotaxis by the gliding, unicellular red algaPorphyridium purpureumwas obtained using interference filters. Cells exposed to 3×10−7mol · m2· s−1of various wavelengths for 72 h showed maximum topotaxis at 420 and 440 nm. The lower threshold for positive, movement was approximately 5×10−8mol · m−2· s−1. Random movement occurred at nonactinic wavelengths, and no movement occurred in the dark. Cell motility appeared to be unaffected by light polarity, suggesting that the photoreceptor(s) for topotaxis and photokinesis are randomly oriented.
AXENIC TISSUE CULTURES FROM THE SPOROPHYTES OFLAMINARIA DIGITATAANDLAMINARIA HYPERBOREA(PHAEOPHYTA)
Authors: Fries Lisbeth 
Published: August 2007

ABSTRACTStarting material for the tissue cultures was the meristematic basal zone of the blade. Pieces treated 30–60 sec in hypochlorite solution were rinsed and placed on agar plates made from the artificial seawater ASP6 F2 solidified with 6 g agar l−1. After 6 weeks colorless callus‐like tissue grew out from some pieces. Treatment with activated charcoal removed some inhibiting substances from the agar medium as numbers of callus developing pieces increased on such plates. A combination of 10−5M NAA and 5 · 10−7M kinetin gave a yellow‐brown tissue. A differentiation in the tissue fromL. hyperboreawas observed as well as the formation of meiospores, which grew out into male and female plants. Thalli of sporophytes were observed but they never reached a length of more than one mm before they died or changed to an irregular pattern of growth.
COMPARATIVE CYTOLOGY AND TAXONOMY OF THE ULVAPHYCEAE. I. THE ZOOSPORE OFULOTHRIX ZONATA(CHLOROPHYTA)1
Authors: Sluiman Hans J. , Roberts Keith R. , Stewart Kenneth D. , Mattox Karl R. 
Published: August 2007

ABSTRACTThis fine structural study of the quadriflagellate zoospore ofUlothrix zonata(Weber & Mohr) Kützing, with special attention to the flagellar root system, demonstrates that it is very similar to the zoospore ofUlva lactucaL. in several aspects. Common features include the presence of a cruciate root system (4‐2‐4‐2 type), a non‐striated band that connects basal bodies, a so‐called terminal cap, and system I and system II striated root components. Only slight differences exist, i.e. in the shape of the terminal cap, and in the number and position of the system II root components. It is concluded that the taxonomic affinities ofU. zonatalie with the Ulvaphyceae sensu Stewart and Mattox rather than with the Chlorophyceae. Additional support for this conclusion is the discovery of tiny, flat body scales on the zoospore ofU. zonata.A summary of the distinctive characteristics of the Chlorophyceae, Charophyceae and Ulvaphyceae reflecting the current state of knowledge is given.
ALIZARIN RED DYE AS A MARKER FOR MEASURING GROWTH INCORALLINA OFFICINALISL. (CORALLINACEAÈ, RHODOPHYTA)1
Authors: Andrake William , Johansen H. William 
Published: August 2007

ABSTRACTThe vital stain alizarin red was incorporated into the calcified walls of incipient medullary cells ofCorallina officinalisL. while they were being produced in a terminal meristem. After about 5 h the stained tier of medullary cells formed a red‐purple band from which additional growth could be measured in the field and in non‐agitated cultures. Alizarin red was also taken up by epithallial cells and one month after staining, plants in the field lacked stained epithallia, whereas those in culture retained some of the stain. Possibly the lack of water motion in culture reduced the epithallial sloughing that occurs in nature. Growth rates measured by this technique were approximately 1.4 mm per month in the field and 1.2 mm per month in culture and were not affected by alizarin red.
ON THE NEED FOR REVISION OF THE TAXONOMY OF EUCHEUMA (RHODOPHYTA) IN FLORIDA AND THE CARIBBEAN SEA1,2
Authors: Cheney Donald P. , Dawes Clinton J. 
Published: August 2007

ABSTRACTExamination of the morphology and anatomy of the Florida species of Eucheuma revealed the presence of two distinct groups of plants. One group, represented by E. isiforme (C. Agardh) J. Agardh, E. nudum J. Agardh and an entity previously referred to as the “Bahia Honda form,” is characterized by terete axes, dense medullae, and stalked cystocarps containing a central fusion cell. The second group, represented by E. gelidium (J. Agardh) J. Agardh, E. acanthodadum (Harvey) J. Agardh and E. echinocarpum Areschough, is characterized by flattened axes, loose medullae, and embedded cystocarps containing a small‐celled, central sterile tissue. As the first step in circumscribing the genus Eucheuma in Florida and the Caribbean Sea, it is suggested that members of the latter group he removed from the genus due to their anomalous cystocarp construction.
PHOSPHORUS UTILIZATION AND STORAGE IN BATCH CULTURES OF THE DINOFLAGELLATE PERIDINIUM CINCTUM F. WESTII1
Authors: Elgavish Ada , Elgavish Gabriel A. , Halmann Mordechai , Berman Thomas 
Published: August 2007

ABSTRACT Peridinium cinctum f. westii (Lemm.) Lef., a dominant species in the phytoplankton of Lake Kinneret was studied in batch cultures. External orthophosphate concentrations were depleted by successive transfers to increasingly lower initial orthophosphate concentrations (P0) of 200, 50, 5, 0.6 and 0.2 μM (culture cycles of 45–64 days).Lower cell yields were obtained as P0 decreased, but growth rates were unaffected. The decrease in an intra‐cellular P pool unextractable by cold 6% trichloroacetic acid (TCA) was shown to be responsible for the effect on cell yields. A 31P nuclear magnetic resonance (NMR) study revealed that the major constituents of this internal phosphorus pool in phosphate‐rich cells were the polyphosphates, organized in rigid aggregates of low mobility. Electron‐dense bodies which were observed in phosphate‐enriched P. cinctum cells further supported the existence of an aggregate structure of the polyphosphates. It is concluded that P. cinctum stores excess orthophosphate as polyphosphates which accumulate in a rigid morphological structure.
PHAGOTROPHIC FEEDING AND ITS IMPORTANCE TO THE LIFE CYCLE OF THE HOLOZOIC DINOFLAGELLATE,GYMNODINIUM FUNGIFORME1
Authors: Spero Howard J. , Morée Montescue D. 
Published: August 2007

ABSTRACTThe holozoic dinoflagellate,Gymnodinium fungiformeAnissimova, has been observed in both asexually and sexually reproducing cultures. Asexual reproduction is characterized by zoosporangium formation and subsequent new cell release. Sexuality is gametic, and planozygotes and hypnozygotes are present. The life cycle is highly dependent on feeding, and in food‐depleted cultures the swimming cells rapidly disappear. These are replaced with resistant long‐term resting cysts. Despite its small size (8.5–19 μm),G. fungiformecan feed on prey as large as the ciliated protozoan,Condylostoma magnumSpiegel (600–1000 μm in length), or small injured metazoans, and has been cultured phagotrophically with the chlorophyte,Dunaliella salinaTeodoresco as a food source. Eleven additional species of algae including 1 chlorophyte, 7 chrysophytes and 3 rhodophytes, however, were not suitable as food sources. Feeding is characterized by the formation of ‘dynamic aggregations’ of hundreds of dinoflagellates that attach to the surface of a prey organism by a peduncle.G. fungiformeingests the cytoplasm or body fluids of its prey and a feeding aggregation can ingest aC. magnumin 20–30 minutes.
SOME ASPECTS OF MORPHOLOGICAL VARIATION IN STEPHANODISCUS NIAGARAE (BACILLARIOPHYCEAE)1
Authors: Theriot Edward , Stoermer Eugene F. 
Published: August 2007

ABSTRACTValves of S. niagarae var. niagarae Ehr. and S. niagarae var. magnifica Fricke from geographically dispersed sediment and plankton collections were observed by light microscopy and scanning electron microscopy (LM and SEM). Measurements made by LM can be arranged so that means and ranges of diameter, areolar density, or strial density intergrade from one population into the next. Mean diameter is negatively related to increasing areolar and strial densities. No unique features observable by SEM distinguish the two described varieties. Thus, S. niagarae var. magnifica, having large diameter valves with low areolar and strial densities, may represent one end of a trend in overall variation in S. niagarae. At the opposite extreme are the populations with small valves and high areolar densities which are often erroneously referred to as S. astraea. Type material of S. niagarae lies intermediate to these forms. Three populations considered in this study have distinct morphological characteristics. Valves from Yellowstone Lake sediments have spine placements distinctly different from valves of all other populations. Specimens from Lake Superior have nearly flat central areas. Ribs of valves from Grand Traverse Bay (Lake Michigan) are covered with granules.
MUCILAGE TUBE MORPHOLOGY OF THREE TUBE‐DWELLING DIATOMS AND ITS DIAGNOSTIC VALUE1
Authors: Cox Eileen J. 
Published: August 2007

ABSTRACTColonies of Berkeleya rutilans (Trent.) Grun., Navicula pseudocomoides Hendey and N. ramosissima (C. A. Ag.) Cleve were examined using light and electron microscopy to elucidate the structure of their mucilage tubes. Each species was found to have a characteristic tube construction which could be used for identification. A summary of features on which these species can be recognized was compiled.
MITOSIS IN THE OCTAFLAGELLATE PRASINOPHYTE,PYRAMIMONAS AMYLIFERA(CHLOROPHYTA)1
Authors: Woods Jerry K. , Triemer Richard E. 
Published: August 2007

ABSTRACTCell division is described in the octaflagellate prasinophytePyramimonas amyliferaConrad and is compared in related genera. Basal bodies replicate at preprophase and move toward the poles. Cells remain motile throughout division. The nuclear envelope disperses and chromosomes begin to condense at prophase. Pairs of multilayered kinetochores are evident on the chromosomes of the metaphase plate. Spindle microtubules extending from the region of the basal bodies and rhizoplasts attach to the kinetochores or extend from pole to pole. Numerous vesicles and ribosomes have entered the nuclear region and the incipient cleavage furrow invaginates. The chromosomes move toward the poles at anaphase leaving a broad interzonal spindle between the two chromosomal plates. The nuclear envelope reforms first around the chromatin on the side adjacent to the spindle poles and later on the interzonal side. The cleavage furrow progresses into the interzonal spindle at telophase. By late telophase the nucleoli have reformed and the chromosomes have decondensed. The interzonal spindle has not been observed late in telophase. As the cleavage furrow nears completion the cells begin to twist and contort, ultimately separating the two cells.
Causation and Responsibility
Authors: Sartorio Carolina 
Published: August 2007

AbstractIn this article I examine the relation between causation and moral responsibility. I distinguish four possible views about that relation. One is the standard view: the view that an agent's moral responsibility for an outcome requires, and is grounded in, the agent's causal responsibility for it. I discuss several challenges to the standard view, which motivate the three remaining views. The final view – the view I argue for – is that causation is the vehicle of transmission of moral responsibility. According to this view, although moral responsibility does not require causation, causation still grounds moral responsibility.
Microbiological Evaluation of the New VITEK 2
Neisseria
-
Haemophilus
Identification Card
Authors: Valenza Giuseppe , Ruoff Claudia , Vogel Ulrich , Frosch Matthias , Abele-Horn Marianne 
Published: August 2007

ABSTRACT

VITEK 2 is an automated identification system for diverse bacterial and fungal species. A new card (the
Neisseria
-
Haemophilus
[NH] card) for the identification of
Neisseria
spp.,
Haemophilus
spp., and other fastidious gram-negative or gram-variable microorganisms has been developed, but its performance in a routine clinical laboratory has not yet been evaluated. In this study, a total of 188 bacterial strains belonging to the genera
Actinobacillus
,
Campylobacter
,
Capnocytophaga
,
Cardiobacterium
,
Eikenella
,
Gardnerella
,
Haemophilus
,
Kingella
,
Moraxella
, and
Neisseria
were investigated. The NH card was able to identify 171 strains (91%) correctly without the need for extra tests; one strain (0.5%) was misidentified, and five strains (2.7%) could not be classified. Eleven strains (5.8%) were identified with a low level of discrimination, and simple additional tests were required to increase the correct-identification rate to 96.8%. The results were available within 6 h. Based on these results, the new VITEK 2 NH card appears to be a good method for the identification of diverse groups of fastidious organisms, which would otherwise require testing with multiple systems. However, more work is needed to evaluate the performance of VITEK 2 with regard to
Haemophilus
,
Actinobacillus
,
Cardiobacterium
,
Eikenella
, and
Kingella
bacteria because of the insufficient number of strains tested in this study. Moreover, further reduction of the detection time would be desirable.
Prolonged Fecal Shedding of Hepatitis E Virus (HEV) during Sporadic Acute Hepatitis E: Evaluation of Infectivity of HEV in Fecal Specimens in a Cell Culture System
Authors: Takahashi Masaharu , Tanaka Toshinori , Azuma Masahiro , Kusano Eiji , Aikawa Tatsuya , Shibayama Takao , Yazaki Yasuyuki , Mizuo Hitoshi , Inoue Jun , Okamoto Hiroaki 
Published: August 2007

ABSTRACT

To investigate the duration of fecal shedding and changing loads of hepatitis E virus (HEV) in feces and serum from patients with acute HEV infection, HEV RNA was quantitated in periodic serum and fecal specimens obtained from 11 patients with sporadic acute hepatitis E. All 11 patients had detectable HEV RNA in serum at admission, with the highest viral load being 1.9 × 10
3
to 1.7 × 10
7
copies/ml, and HEV viremia lasted until days 17 to 48 (mean, 28.3) after the onset of hepatitis. Even at the initial examination on days 10 to 29 (mean, 17.6), the HEV load in fecal supernatant was less than 5.7 × 10
4
copies/ml for 10 of the 11 patients, while for the remaining patient (patient 1) it was markedly high, 2.0 × 10
7
copies/ml on day 22. In addition, although HEV RNA in fecal supernatant continued to be positive until days 14 to 33 (mean, 22.4) for patients 2 to 11, that for patient 1 was detectable even on day 121. HEVs in fecal specimens obtained on days 22, 24, 26, 28, and 30, but not day 121, from patient 1 grew efficiently in PLC/PRF/5 cells, reaching the highest titer of up to 10
7
copies/ml in culture medium on day 50 postinoculation. The HEV genome recovered from patient 1 had 29 unique nucleotides that were not seen in any of the 25 reported HEV isolates of the same genotype over the entire genome, with six amino acid substitutions in the ORF1 protein.
Molecular Epidemiology of
Neisseria meningitidis
Isolates from an Outbreak of Meningococcal Disease among Men Who Have Sex with Men, Chicago, Illinois, 2003
Authors: Schmink Susanna , Watson John T. , Coulson Garry B. , Jones Roderick C. , Diaz Pamela S. , Mayer Leonard W. , Wilkins Patricia P. , Messonnier Nancy , Gerber Susan I. , Fischer Marc 
Published: August 2007

ABSTRACT

We characterized five
Neisseria meningitidis
serogroup C isolates from a Chicago outbreak of meningococcal disease that occurred in 2003 among a community of men who have sex with men. Isolates from this outbreak were identical to each other but distinct from the clone that caused a similar outbreak in Canada in 2001.