bluuebunny/crossref_metadata_2025_split huggingface dataset:
ELECTRON MICROSCOPY OF THE LICHEN PHYSCZA AZPOLIA (EHRH.) NYL.1,2
Authors: Brown R. Malcolm , Wilson Rick 
Published: April 2007

SUMMARYThe ultrastructure of the lichen Physcia aipolia was studied in the desiccated and hydrated states. No significant structural variation between these 2 states was noted for the fungus. The fungus contains unusual ellipsoidal structures heretofore unobserved. Their possible role in the formation of membrane is discussed. The plasmalemma of the fungus is convoluted while that of the alga is smooth. The convoluted projections have a “double‐unit membrane” structure similar to fingerlike projections of the ellipsoidal bodies. With OsO4 fixation crystals are pre‐served, enclosed in unit membrane sacs which extend to the convoluted surface. The pyrenoid of the associated alga does not produce starch in the desiccated condition, and electron‐dense granules are present in the matrix associated with chloroplast lamellae which enter this area. In the hydrated condition, the alga contains abundant starch in the pyrenoid region, and the electron‐dense granules are displaced to the preriphery of the pyrenoid starch. Mitochondria, endo‐plasmic reticulum, and ribosomes are not clearly defined in the desiccated state while they are more so in the hydrated condition. Golgi bodies were not observed in the either lichen component. Finally, no fine structural basis for indicating an exchanged of materials between the alga and fungus was observed except, possibly, the convoluted plasmalemma of the fungus and the smooth plasmalemma of the alga.
LIGHT AND ELECTRON MICROSCOPE OBSERVATIONS ON THE TUBE‐DWELLING DIATOM AMPHIPLEURA RUTILANS (TRENTEPOHL) CLEVE
Authors: Drum Ryan W. 
Published: April 2007

SUMMARY The tubular sheath of Amphipleura rutilans is composed of small fibrils 20–25 A in diameter. The endotubular environment is further partitioned by individual cell sheath formation. The tube boundary seems to be an effective barrier against damage from extreme salinity changes, but does not prevent passage of EDTA, neutral red, surfactants, or caffeine. Terminal swellings develop on growing tips during extremely cold periods. These give rise to 2 or more separate growing tips which proceed to form regular tubes. There was no evidence for sexual reproduction or auxospore formation within the terminal swellings, even though adjacent swellings fused. Bacterial, algal, and fungal epiphytes were abundant on the extratubular surface. Hollow lipid bodies occurred in many cells. A rimring strand of presumed DNA occurs in the chloroplast. It is proposed that the tube material serves not only as a protective boundary but also functions as an active nutrient trap.
FATTY ACIDS IN LOTIC PERIPHYTON: ANOTHER MEASURE OF COMMUNITY STRUCTURE1
Authors: McIntire C. David , Tinsley Ian J. , Lowry Robert R. 
Published: April 2007

SUMMARY The fatty acid spectra of 6 periphyton communities developed in laboratory streams at different combinations of light intensity and current velocity were determined by gas‐liquid chromatography and silver nitrate thin‐layer chromatography. Differences in species composition of the communities apparently had no striking effect on proportions of palmitic and stearic acids, whereas concentrations of myristic, palmitoleic, oleic, linoleic, and linolenic acids and a C20:5 acid were more closely related to taxonomic differences. In general, communities dominated by blue‐green algae exhibited relatively high proportions of oleic, linolenic, and linolenic acids and low proportions of palmitoleic acid and a C20:5 acid, as compared to communities consisting primarily of diatoms. The data also indicated an inverse relationship between fatty acid redundancy and species diversity.
REJUVENATION OF SENESCENT CELLS OF SPONGIOCHLORIS TYPICA2
Authors: McLean Robert J. 
Published: April 2007

SUMMARY Thick‐walled, oil‐filled akinetes of the green alga Spongiochloris typica, long in the stationary phase of growth, were transferred to fresh media. Ultra‐structural changes were observed during a 51‐hr period after transfer. Akinetes, when transferred to fresh media, may follow 1 of 3 pathways:

Remain unchanged; these cells appear to be moribund perhaps due to an over‐accumulation of lipid.
Undergo immediate zoosporogenesis; seems to occur in cells with 4, 8, or more nuclei.
Return to the vegetative state; this was common in smaller cells with less than 4 nuclei; however, zoosporogenesis eventually did occur when 4, 8, or more nuclei were present.
OBSERVATIONS ON PHOTOHETEROTROPHY IN A MARINE DIATOM1
Authors: Bunt John S. 
Published: April 2007

SUMMARY An unidentified species of the diatom genus Cocconeis has been isolated from the sediments of Biscayne Bay, Florida. The organism is capable of utilizing a range of organic substrates, including lactate, in the light but not in the dark, as shown by growth studies. Information is included on changes in cell carbon, nitrogen, and chlorophyll a during growth in batch culture. Data obtained on the kinetics of uptake of lactate and glucose raise questions on the possible ecological significance of photoheterotrophy among marine microalgae, particularly those in estuaries.
SOME CHROMOSOME NUMBERS OF DRAPARNALDIA
Authors: Carroll Jackie Wayne , Deason Temd R. 
Published: April 2007

SUMMARY The variability exhibited by Draparnaldia both in nature and in the laboratory makes it difficult to identify the species. The natural variability of Draparnaldia was amplified by the environmental conditions and the media used in this study. With the hope that chromosome studies would aid in taxonomic characterization by providing additional differentiating criteria, special attention was devoted to adapting techniques which could be used to determine chromosome numbers of Draparnaldia isolates. The chromosome numbers reported herein are as follows: (1) Draparnaldia glomerata, Isolate #1, isolated from Davis Falls, Montevallo, Alabama, was found to have a chromosome number of 13. (2) Draparnaldia Isolate #2, an unidentified species obtained from Anniston, Alabama, was found to have a chromosome number of 13. (3) Draparnaldia acuta, Isolate #3 from Northwood Lake, Northport, Alabama, exhibited 26 chromosomes. (4) Draparnaldia plumosa strain 423 (Indiana Culture Collection), 418/a (Cambridge) was observed to have a chromosome number of 13.
A COMPOSITE RATING OF ALGAE TOLERATING ORGANIC POLLUTION2
Authors: Palmer C. Mervin 
Published: April 2007

SUMMARY From information on pollution‐tolerant algae compiled from reports from 165 authors, the genera and species most often referred to as significant fall into a relatively stable series. Diatoms, pigmented flagellates, green, and blue‐green algae are all well represented among the pollution‐tolerant genera and species. The top 8 genera are Euglena, Oscillatoria, Chlamydomonas, Scenedesmus, Chlorella, Nitzschia, Navicula, and Stigeoclonium, and the top 5 species, Euglena viridis, Nitzschia palea, Oscillatoria limosa, Scenedesmus quadricauda, and Oscillatoria tennis. In some genera, e.g., Euglena, a single species is far more significant than all others as a pollution‐tolerant form. In other genera, e.g., Oscillatoria, only a slight difference distinguishes the pollution tolerance of 2 or more species. Algal genus and species pollution indices arc presented for use in rating water samples with high organic pollution.
QUANTITATIVE CATION REQUIREMENTS OF SEVERAL GREEN AND BLUE‐GREEN ALGAE2
Authors: Gerloff G. C. , Fishbeck K. A. 
Published: April 2007

SUMMARY In contrast with studies which have based essential element requirements of algae on nutrient solution concentrations, in this investigation the requirements of each of 6 species of green and blue‐green algae for calcium, magnesium, and potossium were quantitatively evaluated in terms of critical cell concentrations of the 3 cations. A critical cell concentration was considered the minimum cell content of an element which permitted maximum or near maximum total growth of an organism. In comparison with the needs of angiosperm crop plants, the requirements of all 6 species for calcium were extremely low (critical cell contents of 0.06% or less, oven‐dry basis); requirements for magnesium were equal to or only slightly less than in higher plants (0.15–0.30%) with the exception of Scenedesmus quadricauda (0.05%); and the requirements for potassium varied greatly, from critical levels less than the average values established for higher plants (0.25–0.50%) to values equal to or in excess of higher plant averages (0.80–2.40%). The nutrition of S. quadricauda was of particular interest because of extremely low requirements for all 3 cations. The results provide a more precise and meaningful expression of the essential cation requirements of algae than have previous data. The results also suggest differences in the physiology and functions of cations in the algae studied and in angiosperms which seem worthy of further investigation.
NOTES ON CLADOPHORA (CHLOROPHYCEAE). II. CLADOPHORA CATENATA (LINNAEUS) KÜTZ., 1843, EMEND. V. D. HOEK, 1963
Authors: van den Hoek C. 
Published: April 2007

SUMMARY The species name Cladophora catenata (L.) Kütz. emend, van den Hoek has priority over Cladophora fuliginosa Kütz.
N‐METHYL‐N'‐NITRO‐N‐NITROSOGUANIDINE AS A MUTAGEN FOR BLUE‐GREEN ALGAE: EVIDENCE FOR REPAIR1
Authors: Stevens S. E. , Van Baalen C. 
Published: April 2007

SUMMARY Survival and mutagenesis have been examined in the marine coccoid blue‐green alga, Agmenellum quadruplicatum, after treatment with the chemical mutagen, N‐methyl‐N'‐nitro‐N‐nitrosoguanidine (NTG). When cells were immediately returned to growth conditions following NTG treatment, the survival level was consistently low and essentially independent of the treatment conditions. The types of mutants found paralleled those previously described in the freshwater coccoid, Anacystis nidulans. If, however, cells were kept under very low light intensity, a nongrowth condition, following NTG treatment, viable cell recovery was dramatically increased. This “dim light” repair in A. quadruplicatum has characteristics similar to those reported for the dark repair systems of bacteria and yeast.
EXPERIMENTAL OBSERVATIONS ON THE INFLUENCE OF TEMPERATURE, LIGHT, AND SALINITY ON CELL DIVISION OF THE MARINE DIATOM, DETONULA CONFERVACEA (CLEVE) GRAN2
Authors: Smayda Theodore J. 
Published: April 2007

SUMMARY The influence of 116 combinations of temperature (2, 7, 12, 16 C), salinity (5–35‰ at 5‰ intervals) and light (5 levels) on the mean daily cell division rate (K) of the Narragansett Bay clone of Detonula confervacea was examined following appropriate preconditioning. Growth did not occur at 16 C, but was excellent (K = 1.2–1.5) under certain combinations of light and salinity at 2, 7, and 12 C, being somewhat better at the 2 highest temperature levels. At 32%, and 1100–1200 ft‐c, K increased approximately 2.5 fold from 0.6 to 1.5 between 2 and 12 C. A light‐temperature relationship was found which had the general trend of an increased optimal light intensity with increasing temperature. Within the optimal salinity range of 15–30‰, the optimal light intensity was 200–600 ft‐c at 2 C, 600–1200 ft‐c at 7 C, and 1200–1800 ft‐c at 12 C. The light‐temperature relationship was most pronounced at 2 and 12 C. At 2 C, K decreased with increasing light intensity, but was independent of this factor at higher temperatures. The optimal salinity range of 15–30‰ was independent of temperature negligible growth occurred at 5‰.In situ and in vitro responses of Detonula confervacea to salinity were in general agreement but its pronounced cryophilic preference in nature (usually reaching maximum abundance below 1 C) contrasts with its excellent growth at 12 C in culture. The experiments suggest that termination of the bloom of Detonula confervacea in Narragansett Bay and elsewhere is not solely temperature‐dependent. Temperature does not satisfactorily account for its apparent exclusion from waters contiguous to Narragansett Bay and from other more northerly portions of the northeastern coast of the U.S, or, together with light, for its equally surprising apparent unimportance in Norwegian coastal waters.
PAPENFUSSIELLA CALLITRICHA: NEW OBSERVATIONS ON A LITTLE‐KNOWN ENDEMIC BROWN ALGA FROM SOUTHWEST GREENLAND2
Authors: Wilce R. T. 
Published: April 2007

SUMMARYPapenfussiella callitricha(Rosenv.) Kylin, of the Myriogloia group (Chordariaceae), is an endemic species of west Greenland with a very restricted distribution; it is known from only 3 localities. The collections from which my own description of the plant is taken constitute the first records of the species since Rosenvinge's original collections of 1886. My cytological data are taken from living plants and ecological notes are based upon observations made while I dived with the aid of Scuba equipment. Zoospores liberated in culture medium germinated to produce microthalli, the second microthallus to be described for this algal group. The life history was not completed in culture. However, motile cells released from the plurilocular sporangia of the microthalli continued to produce more microthalli. I suspect that under natural conditions, the microthalli remain vegetative at the close of the daylight season, to resume reproduction late the following spring, giving rise to the next generation of macrothalli.
SCENEDESMUS MORPHOGENESIS. TRACE ELEMENTS AND SPINE FORMATION1
Authors: Trainor Francis R. 
Published: April 2007

SUMMARY When Scenedesmus culture 16, a soil organism with numerous long spines, was grown in axenic culture in a dilute laboratory medium (with approximately 30 mg/liter total salts), spines were not formed. In this medium the organism resembled S. bijugatus, whereas S. longus and S. abundans colonies were typically formed in more concentrated media. Spines were formed on daughter colonies upon transfer to the dilute medium plus additional Fe EDTA or Ca EDTA. No other individual components of the medium did this. Spineless colonies were healthy and green with a well‐defined chloroplast, provided the culture was transferred often. In addition to the absence of spines, cultures in the dilute medium had a linear arrangement of cells within a colony, along with terminal cells 20% shorter than median cells. With 4‐celled spiny colonies all cells were the same length and were alternately arranged.
BONNEMAISONIA HAMIFERAHARIOT IN NATURE AND IN CULTURE23
Authors: Chen L. C.‐M. , Edelstein T. , McLachlan J. 
Published: April 2007

SUMMARYIn culture tetraspores of the sporophyte(Trailliella intricata)ofSonnemaisonia hamiferagave rise to male gametophytes only. In the Gulf of St. Lawrence tetrasporangia occur annually during the autumn, but mature gametophytes have not been recorded. However, gametophytes with antheridia were found during the winter on the Atlantic coast of Nova Scotia. Both phases are capable of vegetative propagation, and this is probably the usual method of reproduction in nature.
CELL DIVISION IN SPIROGYRA. II. CYTOKINESIS
Authors: Fowke L. C. , Pickett‐Heaps J. D. 
Published: April 2007

SUMMARY Cytokinesis in cells of Spirogyra sp. was studied with both light and electron microscopes. Early formation of the cross wall was achieved by annular ingrowth of a septum; the cross wall was completed by a phragmoplast containing Golgi vesicles, longitudinally aligned microtubules, and associated electron‐dense material. Spirogyra may represent an intermediate stage in the evolution of the phragmoplast seen in higher plants.
SEXUAL REPRODUCTION IN CHAETOSPHAERIDIUM GLOBOSUM (NORDST.) KLEBAHN (CHLOROPHYCEAE) AND DESCRIPTION OF A SPECIES NEW TO SCIENCE
Authors: Thompson R. H. 
Published: April 2007

SUMMARY Developmental morphology and sexual reproduction of Chaetosphaeridium globosum are described. Dicoleon nordstedtii is reduced to synonymy with C. globosum. A species new to science, C. gemmatum, is described. Descriptions are given of material collected of C. ovalis and C. pringsheimii accompanied by a key to the 4 species of the genus. The species C. huberi is relegated to species dubium.
PHOSPHORUS CONTENT AND RATE OF GROWTH IN THE DIATOMS CYCLOTELLA NANA AND THALASSIOSIRA FLUVIATILIS
Authors: Fuhs G. Wolfgang 
Published: April 2007

SUMMARYCyclotella nana and Thalassiosira fluviatilis were grown in chemostat and turbidostat units in 1/3 strength artificial seawater supplemented with nutrients and vitamin B12 in excess except for phosphorus (P) which in concentrations of 50 or 100 μg/liter was limiting. Different chemostat and turbidostat settings produced different cell numbers per unit volume which, since external P was practically nil, corresponded to varying amounts of bound P per cell. Growth rate plotted vs. P per cell follows a saturation curve. While no growth occurs at a certain minimum content of bound P, half the maxi‐mum growth rate is observed at twice the minimum level of P,3/4 of the maximum at 3 times the minimum level, etc., the maximum growth rate being defined as that observed during growth unrestricted by P supply at a given set of conditions (light, temperature, salinity, etc.). Temperature and light were varied from 13.5 to 24 C and from 2000 to 6000 lux (continuous and intermittent). An abnormal growth curve was found with C. nana at 24 C and 6000 lux continuous light. Any change in P content of the cells significantly alters cell composition as reflected in P distribution in acid‐soluble, lipid, and acid‐insoluble fractions and in organic carbon content. External P does not immediately enter our equation for growth rate but is one of the factors deter‐mining rate of P uptake and therefore bound P per cell. Conditions governing uptake, however, cannot be adequately controlled in a chemostat and there fore should be determined in a different experimental approach.
CHLOROPLAST INHERITANCE IN COSMARIUM TURPINII BRÉB.
Authors: Korn Robert W. 
Published: April 2007

SUMMARY Chloroplast inheritance was studied in Cosmarium turpinii Bréb. with respect to both vegetative and zygotic transmission. Analyses were carried out on (1) reciprocal haploid x diploid crosses with respect to the number and size of the zygotic chloroplasts, (2) differential survival of chloroplasts in hypnospores of different mating type strains, and (3) the position of the chloroplasts in diploid zygotes. Morphological evidence indicates that the chloroplasts in the mature zygote are derived from the (+) mating type gamete with an infrequent contribution from the (–) mating type gamete. Additional evidence suggests that the chloroplast material of each of 2 Bones arising from the zygote is derived from the plastid material of a semicell of a gamete. Differential survival of the chloroplasts is interpreted as a result of physiological differences between cells of complementary mating types.
SYMBIODINIUM MICROADRIATICUM FREUDENTHAL, A REVISED TAXONOMIC DESCRIPTION, ULTRASTRUCTURE
Authors: Kevin Monica J. , Hall William T. , McLaughlin John J. A. , Zahl Paul A. 
Published: April 2007

SUMMARY The ultrastructure of Symbiodinium microadriaticum in vitro and in the type host Condylactis and Casseopeia is described and contrasted with previous observations on symbionts from Anemonia sulcata and the Pacific Tridacnidae. Its type description is emended with new electron microscopic observations and with a list of alternate hosts, including their distributions.
THE THERMOPHILIC CYANOPHYTES OF ICELAND AND THE UPPER TEMPERATURE LIMIT1
Authors: Castenholz Richard W. 
Published: April 2007

SUMMARY The upper temperature limit for the growth of chlorophyllous cyanophytes was estimated at about 63–64 C by observations of field populations and by the growth of culture isolates at that temperature. Several isolates of Mastigocladus laminosus were made from different Iceland springs and temperatures. A few continued to grow at 62 C and one at 64 C. M. laminosus was the cyanophyte in Iceland tolerant of the highest temperature. The several species or races of narrow‐cell‐form Synechococcus, which almost exclusively inhabit North American and other springs above 62 C and up to about 74 C, were not found in Iceland. According to my observations and those of others, a maximum of 6–8 cyanophyte species occur in waters over 45 C in all of Iceland. Many times this number has been reported from continental regions of great thermal activity. The low number of species and the absence of particular thermophilic cyanophytes may result from inadequate dispersal from other thermal areas since the end of the last glaciation. Environmental inadequacies (e.g., winter darkness, or minimum‐maximum concentrations of nutrients or other solutes) may also be factors in the absence of certain species.
COMPARISON OF HALF‐SATURATION CONSTANTS FOR GROWTH AND NITRATE UPTAKE OF MARINE PHYTOPLANKTON 2
Authors: Eppley Richard W. , Thomas William H. 
Published: April 2007

SUMMARY Growth rates and rates of nitrate uptake by N‐depleted cells were measured for an oceanic diatom, Chaetoceros gracilis, and a neritic diatom, Asterionella japonica, as functions of nitrate concentration of the medium. Both growth and N‐uptake rates appeared to be hyperbolic with nitrate concentration and could be fit to an equation of Michaelis‐Menten form: where v is rate, Vm. is the maximum rate, S is nitrate concentration, and Ksis the half‐saturation constant. Ksvalues for uptake and growth were similar if not identical for each species. Uptake experiments can provide a presumptive measure of Ksfor growth, thought to be an ecologically significant characteristic of a species.
ADAPTATION OF PHOTOSYNTHESIS IN LAMINARIA SACCHARINA (PHAEOPHYTA) TO CHANGES IN GROWTH TEMPERATURE1
Authors: Davison Ian R. 
Published: April 2007

ABSTRACTThe effect of growth temperature on photosynthetic metabolism was studied in the kelp Laminaria saccharina (L.) Lamour. Photosynthesis was subject to phenotypic adaptation, with almost constant photosynthetic rates being achieved at growth temperatures between 0 and 20° C. This response involved: (1) an inverse relationship between growth temperature and photosynthetic capacity, (2) a reduction in the Q10 value for photosynthesis of L. saccharina grown at 0 and 5° C compared with 10, 15 and 20° C grown sporophytes, and (3) an acquired tolerance of photosynthesis to temperatures between 15–25° C (which inhibited photosynthesis in 0 and 5° C grown L. saccharina) in sporophytes grown at 10, 15 and 20° C. The physiological basis of these adaptations is discussed in terms of observed changes in activities and kinetics of the Calvin cycle enzyme ribulose‐1, 5‐bisphosphate carboxylase (oxygenase) and efficiency of light harvesting‐electron transport systems.