bluuebunny/crossref_metadata_2025 huggingface dataset:
CELL DIVISION PERIODICITY IN 13 SPECIES OF MARINE PHYTOPLANKTON ON A LIGHT: DARK CYCLE1
Authors: Nelson David M. , Brand Larry E.
Published: August 2010

The division rates of 26 clonal cultures representing 13 species of planktonic marine algae (6 diatoms, 2 flagellated chrysophytes, 2 coccolithophores, 1 cryptomonad flagellate, I dinoflagellate, 1 green alga) were determined every 2 h for 48 h during exponential growth on a 14:10 LD cycle in nutrient‐replete batch culture. Cyclic oscillations in the division rate were detectable in 22 of these clones. Of 14 diatom clones examined, four displayed nearly constant division rates throughout the LD cycle and ten showed strong periodicity favoring division during the light periods. In contrast, all other algae (12 clones) exhibited division rate maxima during periods of darkness, and clearly detectable decreases in cell number for time intervals of 4–8 h during periods of illumination. Intraspecific differences in division periodicity were found among eight clones of the diatom Thalassiosira pseudonana (Hustedt) Hasle & Heimdal and six clones of the coccolithophore Emiliania huxleyi (Lohm.) Hay & Mohler.
COLONIZATION AND STANDING CROPS OF EPILITHIC ALGAE IN THE SUSQUEHANNA RIVER, PENNSYLVANIA1
Authors: Gale William F. , Gurzynski Andrew J. , Lowe Rex L.
Published: August 2010

A SCUBA diver, using a bar‐clamp sampler, collected quantitative epilithic algae samples from artificial substrates (slate and acrylic plates) and river stones at two stations on the Susquehanna River bottom in 1974. At Falls, Pennsylvania, algal colonization on monthly plates (submerged for ca. 30 day periods) was most rapid between September and October. In winter, when algal density on cumulative plates (submerged 2–13 mo) and on stones present in the river peaked at 18,100 and 21,900 units/ mm2, respectively, colonization of clean monthly plates nearly ceased. Similar colonization patterns were observed in a portion of the river polluted by coal mine drainages (SSES), but expansion of the algae population at SSES was inhibited by iron in the effluents, and densities never exceeded 2,400 units/mm2 on stones or plates. Diatoms composed 95% of the overall standing crop at Falls and 65% at SSES.
ULTRASTRUCTURE OF THE CORALLINACEAE (RHODOPHYTA) II. VEGETATIVE CELLS OF LITHOTHRIX ASPERGILLUM1
Authors: Borowitzka Michael A. , Vesk Maret
Published: August 2010

The ultrastructure of the calcareous red coralline alga Lithothrix aspergillum Gray and the development of the various tissue types has been studied. The sub‐apical meristematic tissue alternately produces genicular or intergenicular cells. The genicular cells rapidly elongate and their cell walls thicken and become denser as more fibrillar wall material is laid down within the cell wall. These cells contain little cytoplasm and few organelles. The inter genicular cells which elongate only slightly during development have a small vacuole and many free starch grains in the cytoplasm. The peripheral cells in each inter genicular layer remain meristematic and form a cortical cell layer over the genicular cells. These cortical cells and the apical meristematic cells are covered by small epidermal cells which have extensive cell wall ingrowths between the chloroplasts. The inter genicular cells are calcified. Although the CaCO3 is laid down within the cell walls, there is always a thin layer of CaCO3‐free organic cell wall material between the plasmalemma and the CaCO3 impregnated wall. Only the distal tips of the genicular cells are calcified. In old genicular tissues of Lithothrix, secondary deposits of CaCO3 of unknown crystallography are also found in the spaces between the cell walls. Thus there appear to be at least two mechanisms of calcification in this alga.
DEVELOPMENT OFJANCZEWSKIA MORIMOTOI(CERAMIALES) ON ITS HOSTLAURENCIA NIPPONICA(CERAMIALES, RHODOPHYCEAE)1
Authors: Nonomura Arthur M.
Published: August 2010

Janczewskia morimotoiTokida was successfully cultured from spore to reproductive maturity on its hostLaurencia nipponicaYamada. The spore penetrates the host without requirement for wound or abrasion sites, growing between host cortical cells and developing a superficial and an endophytic system simultaneously. During the juvenile period, when the parasite is nonpigmented, it differentiates a cortex and the proliferating endophytic filaments enlarge causing a displacement of layers of host cells into the parasitic tissue. Host cells contacted by cells of the parasite exhibit increased wall thickness, cytoplasmic density and vesicle formation. Pit connections between host and parasite cells were rarely observed whereas penetration of host cell walls was seen commonly. As the parasite increases in size, its cells become pigmented evenly throughout the cortex and host cells show less obvious reactions to the parasite. At this same time, the parasite develops branches and reproductive structures. Host plant segments less than 3 cm long failed to grow when infected with spores of the parasite whereas longer segments were not significantly affected by the parasite. In the absence of the host, the parasite cannot complete its development. AlthoughJ. morimotoiis well pigmented at maturity, the absence of pigmentation in the juvenile stage, penetration of host cells, and effect on host growth in culture strongly suggest that it is parasitic during at least its early development.
FEULGEN MICROSPECTROPHOTOMETRIC STUDIES OF PANDORINA MORUM AND OTHER VOLVOCALES (CHLOROPHYCEAE)12
Authors: Coleman Annette W.
Published: August 2010

The nuclear DNA content during normal vegetative growth and division has been examined in three species of Volvocales, Chlamydomonas reinhardtii Dangeard, Pandorina morum Bory, and Volvox carteri f. nagariensis Iyengar. The results are consistent with the nuclear cycle reported in the literature for Eudorina. Nuclear DNA content does not increase during the prolonged cell growth phase. At the time of colony formation, nuclear DNA doubles, the nucleus divides, and this alternation continues until the final 2n complement of progeny nuclei is formed. The 4‐ and 8‐nucleate stages of dividing gonidia of V. carteri have a nuclear DNA content in the same range as the somatic cells; they are not polyploid or polytene. Four normal clones of Pandorina, having 2, 5 or 12 chromosomes, all had similar amounts of DNA per nucleus, suggesting that the species has a nuclear genome of fairly constant size rather than consisting of many strains representing a polyploid series. One unique clone, a hybrid with double the chromosome number of either its parents, had twice as much DNA as the normal clones. The Feulgen spectrophotometric method is sufficiently sensitive to detect 2‐fold differences in DNA content at the level of 2 × 10−13 g of DNA /nucleus, and its use avoids the complications associated with the presence of organelle DNA.
SEASONAL VARIATION IN SUN‐SHADE ECOTYPES OF PLECTONEMA NOTATUM (CYANOPHYTA)1
Authors: Sheridan Richard P.
Published: August 2010

Clonal cultures of the thermophilic alga Plectonema notatum Schmidle were grown from cells collected in winter from the surface and subsurface zones of the cell mat in Jerry Johnson Hot Spring, Idaho. Both surface and subsurface clones exhibited light saturation curves and concentrations of photosynthetic pigments typical of ecotypes highly adapted to shade environments. These winter clones were compared to surface and subsurface clones collected during summer months. This comparison illustrates the seasonal rotation of ecotypes. The shade adapted winter surface and subsurface types dominated the mat during the low light intensity, short photoperiod winter season. With increasing light intensities and photoperiods the winter ecotypes were replaced by the high light intensity adapted summer ecotypes.
OCCURRENCE OF A EUROPEAN RED ALGA (SCHOTTERA NICAEENSIS) IN SOUTHERN AUSTRALIAN WATERS1
Authors: Lewis John A. , Kraft Gerald T.
Published: August 2010

Schottera nicaeensis(Phyllophoraceae, Gigartinales), presently known only from the western Mediterranean Sea and the northeastern Atlantic coasts of Europe, is reported for the first time from the Melbourne region of Port Phillip Bay in southeastern Australia. The species is perennial in the Bay, although tetrasporophytes and cystocarpic plants are commonest in late spring and early summer. This seasonal pattern, and the vegetative habits of plants during the whole of the year, show similarities to populations described by other workers for Northern Hemisphere localities where comparable water temperature and daylength regimes obtain. The small AustralianS. nicaeensiscommunity is found at 5–9 m depths and is concentrated on lighthouse foundations adjacent to the main Port of Melbourne shipping channel. It is hypothesized that the species has recently been introduced into Port Phillip Bay, and a scenario for its possible means of import on ships is suggested.
FACTORS LIMITING EDAPHIC ALGAL BIOMASS AND PRODUCTIVITY IN A GEORGIA SALT MARSH1,2
Authors: Darley W. Marshall , Montague Clay L. , Plumley F. Gerald , Sage William W. , Psalidas Arthur T.
Published: August 2010

A “planted core” system was developed to test the effect of short term (1–2 weeks) experimental manipulation of environmental parameters on edaphic microalgae under field conditions. A large number of small cores (surface area = 7 cm2) were collected, randomized and replanted in the marsh in fiddler crab exclosures with appropriate experimental treatments. Daily enrichment of the cores with NH4+ resulted in significant increases in edaphic primary productivity and levels of chlorophyll a in both summer and winter seasons in the short‐Spartina marsh. Enrichment with a complete nutrient solution caused no further increases. Nutrient enrichment of creekbank sediments was much less stimulatory to the resident algal assemblage. In both sites, but especially in the creekbank, the removal of fiddler crab grazers resulted in significant increases in chlorophyll a and productivity. Experimental manipulation of light intensity showed that the average light intensity reaching the sediment surface was saturating for chlorophyll production in the short‐Spartina marsh. A reciprocal transplant experiment involving unfertilized cores from the short‐Spartina marsh and creekbank marsh demonstrated that NH4+ inputs occurring in the creekbank site rapidly alleviated nitrogen limitation of edaphic algae from short‐Spartina marsh. Algae in creekbank cores incubated in the short‐Spartina marsh were unable to sustain high productivity once the original standing stock of NH4+ declined.
STUDIES ON DEVELOPING AND RELEASED SPERMATIA IN THE RED ALGA, TIFFANIELLA SNYDERAE (RHODOPHYTA)1
Authors: Fetter Richard , Neushul Michael
Published: August 2010

Developing and released spermatia of the red alga, Tiffaniella snyderae (Farl.) Abb. were studied. Spermatia were observed under hydrodynamically defined conditions and found to be released from the exposed spermatangial heads in a spermatium‐plus‐strand unit that remained connected to the spermatangial head. Interactions of single‐spermatial strands resulted in the formation of multi‐spermatial strands as long as 600 μm with as many as 47 spermatia along their length; however, most were 100–200 μm with 8–21 spermatia. Strand length and number of spermatia were correlated. Spermatial strands contracted or extended and rotated as the water velocity past the plant was changed, and in still water the strands retracted into a clump on the spermatangial head surface. Each strand type exhibited a characteristic threshold water velocity at which it reached maximum length, and above which it broke and was carried away. Fluorescence microscopy showed that the strands did not contain nucleic acid (DNA) and could thus be differentiated from filamentous blue‐green algal and bacterial epiphytes. Histochemical staining indicated that the strands and spermatial vesicles contained an acidic, sulfated polysaccharide. Chelation of Ca2+ with EGTA resulted in strand breakdown suggesting that this divalent cation may be involved in strand integrity.

Scanning electron microscopy revealed that release from the spermatangia occurred through tears in the cuticle covering the spermatangial head if it was still present, or from exposed spermatangia. Individual spermatia were attached tangentially to a well‐defined strand 0.64 μm in diameter in the contracted state to 0.2 μm in the extended state. Transmission electron microscopy of spermatangial heads showed that immature spermatangia were characterized by a centrally positioned nucleus and abundant ER cisternae filled with a moderately electron dense granular material. Later in development the spermatangia acquire two spermatial vesicles containing highly convoluted fibrillar contents. The cell becomes polarized with the nucleus displaced apically and the spermatial vesicles occupying the basal half of the spermatangium. At maturity one of the vesicles is released basally. Liberated spermatia contain a membrane‐bound nucleus and mitochondria and are associated with an oblong accumulation of fibrous material similar in size and position to the strand observed with the SEM. These strands are discussed in relation to red algal fertilization and other phases of the red algal life‐history.
MARIPELTA ATLANTICA SP. NOV. (RHODOPHYTA, RHODYMENIALES) A NEW DEEP‐WATER ALGA FROM FLORIDA1
Authors: Eiseman Nathaniel J. , Moe Richard L.
Published: August 2010

A red alga with a cylindrical stipe bearing a single deciduous blade was collected in deep water off the east coast of Florida. It is described as Maripelta atlantica sp. nov., differing from M. rotata (Dawson) Dawson (the type of the genus, from deep water off California and Baja California) chiefly by having an annular tetrasporangial nemathecium on the lower surface of the blade rather than scattered nemathecia on the upper surface. Both species are vegetatively and reproductively distinct from M. thivyae Dawson, which is transferred to Halichrysis. New information is given regarding the reproduction and distribution of M. rotata.
COMPARATIVE KINETIC STUDIES OF NITRATE‐LIMITED GROWTH AND NITRATE UPTAKE IN PHYTOPLANKTON IN CONTINUOUS CULTURE1
Authors: Gotham Ivan J. , Rhee G‐Yull
Published: August 2010

A comparative study of nitrate‐limited growth and nitrate uptake was carried out in chemostat cultures of Ankistrodesmus falcatus (Corda) Ralfs., Asterionella formosa Hass., and Fragilaria crotonensis Kit. In each species growth rate (μ) was related to total cell nitrogen or cell quota (q) by the empirical Droop growth function.

Nitrate uptake was a function of both external N concentration and q. The apparent maximum uptake rate (Vm') at a given μ was inversely related to q – q0, where q0 is the minimum quota. The apparent half‐saturation constant for uptake, (Km') appears to show a slight inverse trend with μ, although statistical analysis shows that this trend is inconclusive. When q approaches q0, Vm' is several orders of magnitude greater than μq, the calculated steady‐state uptake rate. As q increases, however, the difference between these two variables decreases sharply until q approaches qm, the cell quota for nitrogen‐rich cells. At this point the difference between μq and Vm' disappears. This behavior is explained by the feedback regulation of N uptake. The inverse relationship between Vm' and q – q0 can be described by an empirical three‐parameter equation.
TEMPERATURE DEPENDENCE OF GROWTH AND PHOSPHORUS UPTAKE IN TWO SPECIES OF VOLVOX (VOLVOCALES, CHLOROPHYTA)1
Authors: Senft W. Herbert , Hunchberger Robert A. , Roberts Kenneth E.
Published: August 2010

The growth of Volvox globator L. and Volvox aureus Ehr. was measured at five temperatures and nine phosphorus concentrations. Growth rates were hyperbolically related to phosphorus concentrations for all temperatures using a Monod growth model. Optimal growth rates of 1.17 and 1.00 doublings d−1 were obtained at 20°C for V. globator and V. aureus, respectively. Neither species grew at 5°C. The half‐saturation constants for growth, Ks, were lower for V. aureus. Phosphorus uptake by both species was also dependent upon external phosphorus concentrations and temperature. At all temperatures, maximum phosphorus uptake (μmol P colony−1 min−1) was similar for both species; however, the half‐saturation constants for uptake showed significant differences between the species. Comparisons of the kinetic constants for growth and phosphorus uptake suggest that V. aureus will outcompete V. globator under phosphorus limited, conditions.
COMPARATIVE CYTOLOGY AND TAXONOMY OF THE ULVAPHYCEAE. III. THE FLAGELLAR APPARATUSES OF THE ANISOGAMETES OF DERBESIA TENUISSIMA (CHLOROPHYTA)1
Authors: Roberts Keith R. , Sluiman Hans J. , Stewart Kenneth D. , Mattox Karl R.
Published: August 2010

The components of the flagellar apparatuses of the male and female gametes of Derbesia tenuissima (De Not.) Crouan are compared with those in other swarmers of green algae. Both the male and female gametes were found to have a cruciate microtubular root system, a non‐striated capping plate which connects basal bodies, two electron dense terminal caps which partially cover the proximal end of the basal bodies, and two small system II fibrous roots. Similarities exist between these components and those suggested to be typical of ulvalean swarmers. Based upon these similarities, it is proposed that the Caulerpales be classified in the Ulvaphyceae rather than in the Charophyceae or Chlorophyceae.
AN ALTERNATE GROWTH PATTERN FOR LAMINARIA LONGICRURIS1,2
Authors: Anderson M. Robin , Cardinal André , Larochelle Jacques
Published: August 2010

A population of Laminaria longicruris de la Pylaie was followed for a year at Bic Island, Quebec, Canada where nutrient levels in the seawater were elevated throughout the year. Tagged kelp were measured each month for growth and analyzed for alginic acid, laminaran, mannitol, carbon, nitrogen, and nitrate. Maximum growth (3.5 cm · d−1) was observed in June, and minimal growth (0.18 cm · d−1) from December to February, when ice cover limited light levels. No reserves of carbon or nitrate were formed. Laminaran levels remained below 2.7% dry weight while tissue nitrate did not exceed 0.75 μmol · g−1 dry weight. Total carbon produced per plant was 40 g C · yr−1. Nutrient availability enables the kelp to take advantage of summer light and temperature conditions to grow rapidly.
EFFECTS OF Si:P CONCENTRATION RATIOS AND NUTRIENT LIMITATION ON THE CELLULAR COMPOSITION AND MORPHOLOGY OF ASTERIONELLA FORMOSA (BACILLARIOPHYCEAE)1
Authors: Holm Nancy Peterson , Armstrong David E.
Published: August 2010

The freshwater diatom Asterionella formosa Haas. was grown in semicontinuous culture at 20°C under continuous cool‐white fluorescent light of ca. 20 μEin · m−2· s ·−1 in a medium containing Si: P in various concentration ratios. The cell quotas of P and Si changed in relation to the available concentrations of P and Si at constant μ= 0.11 and 0.16 d−1. Under Si‐limitation, the P cell quota increased by over an order of magnitude as the influent [Si:P] decreased. The Si cell quota increased with increase in [Si] in the influent medium, and it increased as [P] increased at a specific [Si]. Under P‐limitation, the P cell quotas were fairly constant and low; the Si cell quotas were relatively high and decreased slightly as influent [P] and [Si] increased. Asterionella stored up to 28 times more P and 2 times more Si than needed. The number of Asterionella cells per colony varied as a function of the influent [Si:P] and nutrient limitation being usually less than or equal to 6 when P‐limited, and greater than 10 when Si‐limited.
ULTRASTRUCTURAL VARIATIONS IN CRYPTOMONAD FLAGELLA1
Authors: Kugrens Paul , Lee Robert E. , Andersen Robert A.
Published: August 2010

The arrangement of flagellar appendages in 19 cryptomonad species was examined and four new flagellar types are described. The first new type has a single row of mastigonemes on both flagella and hairs on the side opposite the mastigonemes. The second type, which is common, has unilateral rows of mastigonemes on both flagella, but no hairs. A third type has an acronematic short flagellum and a single row of mastigonemes on the long flagellum. A fourth type lacks mastigonemes but has a unilateral row of curved “spikes” on the short flagellum and hairs on both flagella. These additional flagellar variations may contribute to a more natural system of classification for cryptomonads.
INTRASPECIFIC VARIATION IN THE DINOFLAGELLATE PERIDINIUM VOLZIP1
Authors: Hayhome Barbara A. , Whitten D. Jean , Harkins Kristi R. , Pfiester Lois A.
Published: August 2010

Clonal isolates of Peridinium volzii Lemmerman were analyzed morphologically and biochemically. Morphological observations at the light microscope level show the clones to be different varieties and forms of the same species. Biochemical analysis by enzyme electrophoresis and flow cytometric determination of nuclear DNA quantities indicates that these isolates are genetically heterogeneous without any clear correlation existing between morphological variation and biochemical variation. Isozyme analysis, however, indicates that strains from the same location are generally more related to each other than they are to isolates with other geographical origins. In general, our results suggest the presence of genetic redundancy and a multiclonal origin for individuals of the same species present in the same locale.
HETEROCOCCUS ENDOLITHICUS SP. NOV. (XANTHOPHYCEAE) AND OTHER TERRESTRIAL HETEROCOCCUS SPECIES FROM ANTARCTICA: MORPHOLOGICAL CHANGES DURING LIFE HISTORY AND RESPONSE TO TEMPERATURE1
Authors: Darling Richard B. , Friedmann E. Imre , Broady Paul A.
Published: August 2010

Strains of Heterococcus endolithicus sp. nov., H. pleurococcoides Pitschmann, H. caespitosus Vischer, and H. protonematoides Vischer isolated from terrestrial habitats in Antarctica were studied in culture. Morphology of the algae changes with stage in life history. The characteristic branching patterns are not present in very young or old cultures. Filament formation is suppressed when cultures are grown outside their optimal temperature range.
STUDIES OF MESOHERBIVORY IN AQUARIA AND IN AN UNBARRICADED MARICULTURE FARM ON THE CHINESE COAST1
Authors: Brawley Susan H. , Xiugeng (X. G. Fei) Fei
Published: August 2010

The effects upon macrophytic and epiphytic algae of caprellid amphipods, including Caprella irregularis Mayer, and of gammarid amphipods, including Ampithoe lacertosa Bate, Jassa falcata (Montagu) and Pontogeneia rostrata Gurjanova, were studied in aquaria and in a coastal mariculture farm near Qingdao, People's Republic of China. The macrophytic species studied included Enteromorpha linza (L.) J. Agardh, Gracilaria asiatica Zhang & Xia, Gracilaria lemaneiformis (Bory) Weber‐van Bosse and Scytosiphon lomentaria (Lyngbye) C. Agardh. These algae and amphipods were selected for study because of their local abundances. Aquarium experiments demonstrated that C. irregularis, J. falcata and P. rostrata feed on ephemeral/epiphytic algae. A. lacertosa (adults and juveniles) ate Gracilaria but preferred E. linza. The different species of amphipods had substantially different patterns of daily activity.

Caprellids prevented epiphytic overgrowth of G. asiatica when added to plants in an experimental, openocean, mariculture farm, despite the presence of numerous amphipod predators (e.g. the fishes Hexagrammos otakii Jordan & Starks and Sebastes thompsoni Jordan & Hubbs). Periodic removals of all (naturally colonizing) amphipods from another group of plants in the farm resulted in heavy epiphytic overgrowth. Since these results were obtained in an unbarricaded mariculture farm, we conclude that mesoherbivores may have large effects upon algal community structure in temperate intertidal and subtidal habitats.
GRAZING OF FRESHWATER RHODOPHYTA1
Authors: Hambrook Julie A. , Sheath Robert G.
Published: August 2010

ASTRACT

Grazing of freshwater Rhodophyta was examined from three perspective: observation of algal fragments in gut contents of herbivores collecte from streams with populations of red algae, measurement of ignestion rates of three inveratebrates in single diet and choice experiments and analysis of potential food value of the rhodophytes by determining protein, carobohydrate, lipid and estimated caloric contents. The algal thallus forms studied were Audouinella violacea (Kütz.) Hamel, which consists of simple filaments growing in dense tufts, Batrachospermum virgatum (Kütz.) Sirod., which is a densely branched mucilaginous filament, and Tuomeya americanna (Harv.) Papenfuss, which is a branched cartilaginous psedoparenchyma. The thirteen invertebrate taxa containing pieces of one or more of these algae in theri guts included two amphipods, two mayfly larvae, three caddisfly larvae, one beetle larva, four chironomids and one snail. The frequencies with which the Rhodophyta were found in the gut contents were as follows: Audouinella 31%, Tuomeya 38%, Batrachospermum 46% and “chantransia stages” 54%. In all of the individual and choice experiments, Audouinella was ingested at the greates rate, followed by Batrachospermum and then Tuomeya, regardless, of the grazer. Audouinella had the highest protein and lipid contents while Tuomeya displayed the opposite trent. All three rhodophytes had very large calofic values (5.0–6.8 kcal μg−1dry weight) due to their high lipid and low ash contents. Therefore, preferential grazing of Audouinella appears to be bases on its simple thallus and high protein contents rather than its calorific value.
DISTRIBUTION OF THE GENUS CYCLOTELLA IN RELATION TO pH IN PRECAMBRIAN SHIELD LAKES: IMPLICATIONS FOR DIATOM‐INFERRED pH1
Authors: Taylor M. C. , Duthie H. C. , Smith S. M.
Published: August 2010

Recent research on relationships between diatoms and pH suggests that the genus Cyclotella exhibits a strong relationship with lake acidity, being almost totally absent below pH 5.5. This decline has been used as an indicator of lake acidification in paleolimnological studies. In this study C. stelligera V.H. and C. kützingiana Thwaites were abundant in Precambrian Shield lakes with pH as low as 4.5. Cyclotella comta (Ehr.) Kütz. was found in lakes of pH < 5.5, but maximum abundance was observed in lakes of pH > 5.5. Cyclotella michiganiana Skv. was found in lakes of pH < 6.0. These results indicate that the use of C. stelligera, C. kützingiana, and possibly C. comta, in paleolimnological investigations of lake acidification, should be approached with caution. These taxa may exhibit a decline in abundance with decreasing lakewater pH, but this is partially a morphometric effect not necessarily related to anthropogenic acidification.
ENTOSIPHON SULCATUM (EUGLENOPHYCEAE): FLAGELLAR ROOTS OF THE BASAL BODY COMPLEX AND RESERVOIR REGION1,2
Authors: Solomon Jean A. , Walne Patricia L. , Kivic Peter A.
Published: August 2010

The flagellar root system of Entosiphon sulcatum (Dujardin) Stein (Euglenophyceae) is described and compared with kinetoplastid and other euglenoid systems. An asymmetric pattern of three microtubular roots, one between the two flagellar basal bodies and one on either side (here called the intermediate, dorsal, and ventral roots), is consistent within the euglenoid flagellates studied thus far. The dorsal root is associated with the basal body of the anterior flagellum (F1) and lies on the left dorsal side of the basal body complex. Originating between the two flagellar basal bodies, and associated with the basal body of the trailing flagellum (F2), the intermediate root is morphologically distinguished by fibrils interconnecting the individual microtubules to one another and to the over lying reservoir membrane. The intermediate root is often borne on a ridge projecting into the reservoir. The ventral root originates near the F2 basal body and lies on the right ventral side of the cell. Fibrillar connections link the membrane of F2 with the reservoir membrane at the reservoircanal transition level. A large cross‐banded fiber joins the two flagellar basal bodies, and a series of smaller striated fibers links the anterior accessory and flagellar basal bodies. Large nonstriated fibers extend from the basal body complex posteriorly into the cytoplasm.
COCCOLITH‐ASSOCIATED POLYSACCHARIDES FROM CELLS OF EMILIANIA HUXLEYI (HAPTOPHYCEAE)1
Authors: Borman Anton H. , de Jong Elisabeth W. , Thierry Remi , Westbroek Peter , Bosch Leendert , Gruter Marijke , Kamerling Johannes P.
Published: August 2010

Coccoliths of Emiliania huxleyi (Lohmann) Hay and Mohler, a unicellular calcifying alga, consist of calcite closely associated with an acidic, Ca2+‐binding polysaccharide. This polysaccharide is thought to play a regulatory role in coccolith synthesis by interfering with CaCO3 crystallization. Here we show that the polysaccharides from three different strains, A 92, L and 92 D, all inhibit the precipitation of CaCO3 in vitro to the same extent. The monosaccharide compositions of the A 92 and L polysaccharide are similar. The 92 D material, however, deviates from the other two: it contains significantly lower amounts of methylated sugars and ribose, and elevated levels of rhamnose and galactose. It also contains antigenic determinants not detected in the A 92 and L polysaccharides. In contrast to the latter two macromolecules the 92 D polysaccharide migrates as two bands upon polyacrylamide gel electrophoresis, possibly resulting from complexing with small amounts of protein. The coccolith polysaccharide from L cells, cultured at an elevated growth rate, also migrates as two bands. This phenomenon is due to an increase in molecular size distribution. The results suggest that certain properties of the molecule may be subject to variation without interfering with its function.
MASSIVE ACCUMULATION OF PHYTOENE INDUCED BY NORFLURAZON IN DUNALIELLA BARDAWIL (CHLOROPHYCEAE) PREVENTS RECOVERY FROM PHOTOINHIBITION1
Authors: Ben‐Amotz Ami , Gressel Jonathan , Avron Mordhay
Published: August 2010

The effects of nanomolar to micromolar concentrations of the herbicide norflurazon were studied in Dunaliella bardawil Ben‐Amotz et Avron, a β‐carotene‐accumulating halotolerant alga. The large amount of β‐carotene which Dunaliella bardawil can contain, around 8% of the algal dry weight, is reduced to 0.2% by treatment with 100 nm norflurazon. Simultaneously, phytoene is accumulated to a similar level of about 8%. The gradual increase in phqtoene content, in response to increasing norflurazon concentrations, corresponds to the decrease in β‐carotene, with no evident change in other isoprenoid intermediates. Carotene‐rich Dunaliella bardawil is substantially resistant to high‐intensity photoinhibition. This resistance is lost in cells grown to contain low & carotene and in the nor‐urazon‐treated phytoene‐rich cells. These obseruations are in agreement with the hypothesis that the accumulated β‐carotene in Dunaliella bardawil portects the cells against injury by excessive irradiation.
INCOMPLETENESS OF THE COCCOSPHERE AS A POSSIBLE STIMULUS FOR COCCOLITH FORMATION INPLEUROCHRYSIS CARTERAE(PRYMNESIOPHYCEAE)1
Authors: van der Wal Paul , de Vrind Johannes P. M. , de Vrind‐de Jong Elisabeth W. , Borman Anton H.
Published: August 2010

Pleurochrysis carterae is a marine biflagellate that produces calcified structures called coccoliths. The coccoliths are formed inside the cells and released from the latter after formation. The light dependence of calcium incorporation in this species was studied using45Ca as a tracer. Cells exposed to a repeating cycle of 16 h of light and 8 h of darkness incorporated calcium in extracellular coccoliths at a more or less constant rate throughout a cycle. The cells divided during the dark periods with a concomitant decrease in size. Their size increased during the light periods. Coccolith formation in cells incubated in continuous darkness was greatly reduced and finally ceased. These cells did not divide and did not increase in size. Removal of extracellular coccoliths prior to the calcium incorporation experiments stimulated coccolith formation both in dark‐incubated cells and in cells exposed to a repeating light‐dark cycle. Cells in the stationary phase of growth ceased producing coccoliths. Calcification could be induced in these cells by removal of the extracellular coccoliths. Based on these findings we suggest that cells of Pleurochrysis carterae tend to produce a complete cover of coccoliths and that the available cell surface is a factor controlling coccolith formation.
EFFECT OF LIGHT CYCLE ON DIATOM FATTY ACID COMPOSITION AND QUANTITATIVE MORPHOLOGY1
Authors: Sicko‐Good Linda , Simmons Mila S. , Lazinsky Diane , Hall Janet
Published: August 2010

Quantitative cytological and fatty acid composition was determined for the diatom Cyclotella meneghiniana Kütz, Data from four separate experiments were examined to elucidate changes that may occur with respect to daily photoperiod. Overall, fatty acid composition is similar to that reported for other diatoms with the exception that the C16 fatty acids constitute approximately 70% of all fatty acids. The major fatty acids are C14:0, 16:1, 16:0, 18:0, and 20:5. Fatty acids that are present in minor amounts are iso‐14:0, iso‐15:0, 15:0, 17:0, 18:4, 18:2, 18:1, 19:0, 20:0, 22:0, and 23:0.

Cytological composition is similar to that previously reported with the chloroplast and vacuole being the largest compartments within the cell. Changes in both cytological and fatty acid composition were studied with respect to the light / dark cycle. Chloroplast and lipid relative volume are greatest during the early part of the dark period. Nuclear relative volume is lowest in the dark and increases throughout the light period.

Total unsaturated fatty acids, including the C20:5 fatty acid, are lowest in the early part of the light period and highest in the dark. The sum of the C16 fatty acids remains constant at 70% of total fatty acids in the cells throughout the light/dark cycle, although percent composition of these two fatty acids shifts.

The data suggest that cyclical changes occur in both quantitative morphology and fatty acids composition with respect to daily photoperiod. The cells, although not rigidly synchronized, most likely divide in the latter part of the dark period or in the first hours of the light period. Lipids increase dramatically in the dark. The ecological implications of lipid storage are discussed in relation to lipophilic toxicants.
Views of People with Intellectual Disabilities of Their Present and Future Living Arrangements
Authors: McConkey Roy , Sowney Margaret , Milligan Victoria , Barr Owen
Published: August 2010

Abstract  To determine personal perceptions and preferences of present and potential living arrangements, 180 adults with intellectual disabilities were recruited to participate in 20 focus groups held across Northern Ireland. About half were living with family carers and the balance in a range of other types of accommodations. Verbal probing and video clips were used to elicit views on four different living options (residential homes, small group homes, supported living, and living with a nonrelated family). Four personal preference themes emerged that were common to all participants irrespective of where they lived: having their own bedroom, participating in household activities; having access to community activities, and maintaining contact with family and friends. Adults living on their own or in supported housing valued their independence and having access to support staff, whereas adults living in residential homes spoke of the importance of relationships with co‐residents and staff. Overall, most of the adults were content with their present situation, although small group homes and supported living arrangements were the most popular alternatives to living with their families. The discussion group process was useful in eliciting comments and offering participants a chance to reflect on their personal perceptions of housing options. Overall, the findings point to the need for greater consideration of personal preferences in home option choice‐making by housing and services providers.
Early Comprehension Instruction for Spanish–Speaking English Language Learners: Teaching Text–Level Reading Skills While Maintaining Effects on Word–Level Skills
Authors: Solari Emily J. , Gerber Michael M.
Published: August 2010

This study investigated the effects of three instructional conditions on precursors to successful reading for Spanish–speaking English language learners (ELL). The study was conducted using a randomized, alternate treatment control group design specifically targeting phonological awareness (PA) listening comprehension (LC), and decoding in a sample of ELL ( N= 82) including students who were and were not at risk for later reading failure. Two randomly assigned experimental intervention groups and one treatment control group were created to test the effectiveness of three instructional interventions that differed in the relative amount of time used for instructing the word– and text–level targeted skills. Specifically, the two experimental intervention groups received different doses of LC relative to PA instruction, creating a LC Concentration group and a PA Concentration group. The treatment control group received only PA and alphabet knowledge instruction (word–level skills). Results indicated that both at–risk and not–at–risk ELLs in the LC Concentration group outperformed students in the other groups on almost all measures, including PA skills, despite minimal amounts of instructional time–targeting word–level skills. These data extend the existing literature by lending empirical support to the use of a LC component in early reading interventions for young ELL.
A Content Analysis of Learning Disabilities Research & Practice: 1991–2007
Authors: Vostal Brooks R. , Hughes Charles A. , Ruhl Kathy L. , Benedek–Wood Elizabeth , Dexter Douglas D.
Published: August 2010

The purpose of this review was to analyze the content of Learning Disabilities Research & Practice to identify prevalent topics and types and proportions of articles published from 1991 through 2007. Also analyzed was the nature of the research reported including designs, participants, interveners, and settings. Analysis indicated that the three most prevalent topics were reading, assessment and identification, and inclusion. Furthermore, 57 percent of the content reflects original research with almost half of these being descriptive in nature. Position papers constitute the most common form of nonresearch articles. Students with learning disabilities as well as those identified as being at risk were the populations studied most often and studies were largely conducted in elementary or middle school classrooms (either special education or general education) with the intervention delivered by a teacher in almost half the studies. More detailed results of the overall analysis along with discussion of the findings are also presented.
Community Participation, Social Ties, and Use of the Internet
Authors: Stern Michael J. , Dillman Don A.
Published: August 2010

Some argue that use of the Internet tends to pull people's interests away from their local area and weaken community ties (e.g., Kraut et al., 1998). Others argue that the Internet is frequently used to strengthen local ties, and is becoming a tool for helping communities organize to achieve local interests (Hampton and Wellman, 2003). Our results from a 2005 random sample mail survey of 1,315 households in a rural region of the Western United States suggest that increased Internet usage is positively related to nominal and active levels of community participation while at the same time supporting affective networks outside the local area. The location of these communities in a rural region of the West and their substantial distance from a larger population concentration provide the opportunity to draw implications for community development in the Information age and address theoretical concerns about the effects of information technologies on communities of place and local social capital.
A THEORETICAL ANALYSIS OF DESIGN ISSUES IN MEDICAL SAVINGS ACCOUNTS: THE POLICY IMPLICATIONS
Authors: Ambrose Jan M. , Butler Ann
Published: August 2010

Abstract: Numerous methods for helping consumers deal with medical care costs have been suggested. One way that has been discussed is the use of Medical Saving Accounts. A pilot program introducing Medical Spending Accounts was passed by Congress as part of the Health Insurance Reform Act of 1996. The authors review the major points of this program and attempt to examine what impact this program could have on medical care cost.
POTENTIAL CONSEQUENCES FOR EMPLOYERS OF SOCIAL SECURITY “PRIVATIZATION:” POLICY RESEARCH IMPLICATIONS
Authors: Olsen Kelly A. , Vanderhei Jack L.
Published: August 2010

Abstract:While traditional fixes to restore Social Security to actuarial balance have known consequences for employers, opinion polls show strong public support for nontraditional approaches, e.g., the stock market investment of Social Security funds (privatization). The authors examine some of the complex assumptions which have been raised as the basis for determining if privitization would benefit employers and discuss the lack of research available to support or dispute the validity of some of these assumptions.
MODELING IMPERFECT KNOWLEDGE IN RISK MANAGEMENT AND INSURANCE
Authors: Jablonowski Mark
Published: August 2010

Abstract: The author examines the problems for risk managers associated with knowledge imperfections. He describes how fuzzy logic can be used to deal with situations when there is a lack of knowledge
ISSUES IN INSURANCE AND RISK MANAGEMENT EDUCATION
Authors: Cassidy Steve
Published: August 2010

Abstract: The risk management and insurance discipline faces a number of challenges. The author poses some questions which focus on those challenges.
Crack‐Free Drying of Ceramic Foams by the Use of Viscous Cosolvents
Authors: Fuks David , Shter Gennady E. , Mann–Lahav Meirav , Grader Gideon S.
Published: August 2010

Ceramic foams are being used in numerous industrial applications such as high‐temperature thermal insulation, hot gas particulate filters, molten metal filters, catalyst support, and cores in high‐ temperature structural panels. The growing usage ceramic foams stems from the favorable properties such as low density, low thermal conductivity, and from their thermal and chemical stability. Recently Gauckler and colleagues developed a new method to produce ceramic foams. This method involves introducing gas bubbles into highly concentrated colloidal suspensions. The foam structure is stabilized by the suspended particles which align at the liquid/gas interface. Following the foaming stage, the wet green foams are dried and sintered. We have found that when making large foam bodies (i.e., >100 mm), cracks formation during the drying stage became a major issue. Following the rational of Scherer and Brinker in the drying of gels, we propose a model that explains the cracks formation in the foams and suggest a different procedure for successful drying of this system. Our solution is based on the addition of miscible cosolvents with low volatility to the aqueous phase. In this paper, we present the effectivity of different cosolvents in solving the cracking problems of large objects.
Hydrogen Gas Permeation Through Al2O3–SiO2 GlassesContaining Metal Ions
Authors: Nogami Masayuki , Shiiba Hiromasa , Kleine Guihlherme A. , Nakayama Masanobu , Hayakawa Tomokatsu
Published: August 2010

We reported in this paper on permeation behaviors of hydrogen gas in alumino‐silicate glasses doped with Eu3+, Nd3+, and Cu+ ions. The permeation coefficients determined by monitoring the gas flow rate were ∼10−13–10−12 mol·(m·s·Pa)−1 in the temperature range of 300°–600°C, which were two orders of magnitude higher than SiO2 glass. It was found that when hydrogen gas is loaded, it diffuses in glass, followed by reducing the Eu3+ and Cu+ ions and forming hydroxyl bonds. The hydrogen gas permeation was also investigated from the formation of hydroxyl bonds, the values of which were smaller than those determined from the gas permeating test. The precipitated copper metal particles were removed by etching in acid solution, resulting into the increased permeation coefficients. On the other hand, the Eu3+‐containing glasses exhibited decreased coefficients by heating in hydrogen gas.
High Surface Area Nanomacroporous Bioactive Glass Scaffold for Hard Tissue Engineering
Authors: Wang Shaojie , Jain Himanshu
Published: August 2010

Formation of sufficiently large three‐dimensional (3D) nanomacroporosity in bone scaffolds remains a challenge in spite of several methods reported in literature. It is required for tissue ingrowth and for the concurrent degradation of implanted structure. We report a new technique for fabricating superior high surface area, nanomacroporous bioactive glass scaffold, which combines the sol–gel process and polymer sponge replication method. The formation of 3D structure is demonstrated in 70 mol% SiO2–30 mol% CaO glass composition as an example, which is uniform across the sample. It consists of open, interconnected macropores with size from 300 to 600 μm, as desired for tissue ingrowth. At the same time, coexisting nanopores provide high‐specific surface area (∼184 m2/g), which is needed for enhancing the structure's degradation rate. These bioscaffolds hold promise for applications in hard tissue engineering.
Growth of One‐Dimensional Nanostructures in Porous Polymer‐Derived Ceramics by Catalyst‐Assisted Pyrolysis. Part II: Cobalt Catalyst
Authors: Vakifahmetoglu Cekdar , Colombo Paolo , Carturan Sara Maria , Pippel Eckhard , Woltersdorf Jörg
Published: August 2010

Via catalyst‐assisted pyrolysis, Si3N4 and SiC nanowires were produced on the cell walls of polymer‐derived ceramic foams. The pyrolysis atmosphere and temperature were the main parameters affecting their development: silicon nitride single‐crystal nanowires formed under nitrogen, while silicon carbide ones were produced under argon, and their amount increased with the increasing pyrolysis temperature. Brunauer–Emmett–Teller analysis showed that the presence of the nanowires afforded high specific surface area (SSA) values to the macroporous ceramic foams, ranging from 10 to 110 m2/g. Co‐containing samples developed higher SSA values, especially after pyrolysis at 1400°C in N2, than samples containing Fe as a catalyst. The differences were explained in terms of morphology (diameter and assemblage), which depended on the processing conditions and the catalyst type (Co or Fe).
Occupational methacrylate and acrylate allergy – cross‐reactions and possible screening allergens
Authors: Aalto‐Korte Kristiina , Henriks‐Eckerman Maj‐Len , Kuuliala Outi , Jolanki Riitta
Published: August 2010

Background. Acrylic resin monomers, especially acrylates and methacrylates, are important occupational allergens.

Aims. To analyse patterns of concomitant patch test reactions to acrylic monomers in relation to exposure, and to suggest possible screening allergens.

Patients/methods. We reviewed the patch test files for the years 1994–2009 at the Finnish Institute of Occupational Health for allergic reactions to acrylic monomers, and analysed the clinical records of sensitized patients.

Results. In a group of 66 patients allergic to an acrylic monomer, the most commonly positive allergens were three methacrylates, namely ethyleneglycol dimethacrylate (EGDMA), 2‐hydroxyethyl methacrylate (2‐HEMA) and 2‐hydroxypropyl methacrylate (2‐HPMA), and an acrylate, namely diethyleneglycol diacrylate (DEGDA). The patterns of concomitant reactions imply that exposure to methacrylates may induce cross‐reactivity to acrylates, whereas exposure to acrylates usually does not lead to cross‐allergy to methacrylates. Screening for triethyleneglycol diacrylate (TREGDA) in the baseline series was found to be useful, as 3 of 8 patients with diagnosed occupational acrylate allergy might have been missed without the screening.

Conclusions. A short screening series of four allergens, EGDMA, DEGDA, 2‐HPMA and pentaerythritol triacrylate (PETA), would have screened 93% of our 66 patients; each of the remaining 5 patients reacted to different acrylic monomer(s).