bluuebunny/crossref_metadata_2025_split huggingface dataset:
PHOSPHORUS, NITROGEN AND THE GROWTH OF ALGAE IN LAKE KINNERET1
Authors: Serruya Colette , Berman Thomas 
Published: August 2007

SUMMARYThe intracellular concentrations of carbon, nitrogen, phosphorus and chlorophyll a of phytoplankton and zooplankton in Lake Kinneret were determined from 1969 to 1973. The ratios C:P, C:N, chlorophyll a:P, chlorophyll a:N of the algae showed fluctuations which could be related to the nutrient conditions that influence the annual pattern of phytoplankton development, especially in respect to the dinoflagellate bloom of Peridinium cinctum (OFM) Ehr. f. westii (Lemm.) Lef. Relatively high intracellurar P values at the start of the bloom indicated adequate availability of this nutrient and luxury consumption over a short period of time. Later, Peridinium continued to grow despite unusually high C:P ratios (> 300:1). In most years, phosphorus may have eventually limited growth, however, in 1970, the bloom censed despite comparatively high intracellular P concentrations. These observations, together with supplementary evidence from nutrient addition experiments and determinations of specific alkaline phosphatase levels, indicated that, for most of the growth phase of the bloom, Peridinium cells were not directly limited by P. The decline of the bloom usually, but not always (e.g., in 1970), was marked by very high C:P ratios. Thus, a shortage of P may often be a contributory factor to the cessation of the Peridinium bloom and may be limiting phytoplankton growth in the fall. Over the years 1969–73, possibly due to an overall drop in salinity, there appears to be a trend to lower levels of biologically bound phosphorus in Lake Kinneret, without a concomitant decrease in carbon biomass.
A STUDY OF THE SPERMATOZOIDS OF DICHOTOMOSIPHON TUBEROSUS (CHLOROPHYCEAE)1
Authors: Moestrup Øjvind , Hoffman Larry R. 
Published: August 2007

SUMMARYSpermatozoids of the siphonous green alga Dichotomosiphon tuberosus (A. Br.) Ernst are specialized gametes which differ in many respects from other green algal motile cells, but whose microanatomy nevertheless indicates its chlorophycean affinities. Each cell is anteriorly biflagellate and contains an irregularly shaped nucleus attached to the flagellar bases by a complex support apparatus. There is a single reduced chloroplast in each spermatozoid and numerous (50–100) minute spherical mitochondria, only 0.3 μm diam. These move vigorously in the living cell and when viewed with the light microscope they bear a striking resemblance to bacteria. Rather unexpectedly, no contractile vacuoles could be detected, even though the gametes are naked freshwater cells. Daring spermatogenesis the nucleoli of the vegetative cells disperse and are replaced by a large dense body presumably formed from either nucleolar material or condensed chromatin. The flagellar apparatus includes a cruciate flagellar root system, a feature now known to be characteristic of most green algae, exceptions being those putative ancestors of the higher plants and bryophytes. Discharge of spermatozoids from the antheridia is extremely rapid and the whole process may be finished in 30 sec. The antheridium lacks a pore apparatus, but at maturity bursts open explosively at the apex. Phyletic affinities are discussed and it is concluded that the ultrastructure of the motile cells does not, at this time, support the separation of the siphonous green algae from other green algae into a separate class.
COLACIUM LIBELLAE SP. NOV. (EUGLENOPHYCEAE), A PHOTOSYNTHETIC INHABITANT OF THE LARVAL DAMSELFLY RECTUM1
Authors: Rosowski James R. , Willey Ruth L. 
Published: August 2007

SUMMARY Colacium libellae sp. nov., in the non‐flagellated palmella stage and lacking stalks, lines the cuticle of the rectum of damselfly larvae, forming a conspicuous green plug. In culture this species forms highly‐branched colonies of stalked cells. The cells tire often elongated to twice the size of most motile cells (40–50 × 6–10 μm), with parallel sides and rounded apices. These features are distinctive when comparisons are made among clones of related species in soil‐water‐pea medium. C. libellae established itself in the rectum of previously Colacium‐free larvae of the damsel fly Anomalagrion hastatum whereas a clone of C. vesiculosum and C. mucronatum did not.
MOLYBDENUM DEPENDENCE, NITRATE UPTAKE AND PHOTOSYNTHESIS OF FRESHWATER PLANKTON ALGAE1,2
Authors: Wallen D. G. , Cartier L. D. 
Published: August 2007

SUMMARYThe effects of molybdenum on photosynthesis and nitrate uptake by two species of freshwater algae, Navicula pelliculosa (Bréd.) Hilse and Chlamydomonas reinhardtii Dang. Were examined. Photosynthetic rates in cells of N. Pelliculosa deprived of Mo for 48 h were significantly lower than in nondeprived cells; the rates were 2.6 and 4.5 μg C/106 cells/h, respectively. There was no significant reduction in photosynthetic rates of C. reinhardtii under the 2 treatments, the rates were both ca. 6.0 μg C/106 cells/h. These observed rates in the 2 species were not altered by added Mo concentrations as high as 1.0 ppm. The chlorophyll a values in 48 h Mo‐deprived cells were 1.15 μg/106 cells compared to 1.57 μg/106 cells provided with this metal. Molybdenum deficiency did not affect the chlorophyll a concentration in Chlamydomonas; the chlorophyll levels were 2.44μg/106 cells.Nitrate uptake by Mo‐deprived cells of N. Pelliculosa was significantly lower than in cells cultured in Mo; the rates were 0.087 and 0.238 μM NOa−/106 cells/h, respectively. Uptake rates by C. reinhardtii were similar with or deprived of Mo. The Km values for No3− uptake were 14.9 and 148.0 μM for N. Pelliculosa and C. reinhardtii, respectively.
LIGHT/DARK‐PHASED CELL DIVISION IN EUGLENA GRACILIS (Z) (EUGLENOPHYCEAE) IN PO4‐LIMITED CONTINUOUS CULTURE1
Authors: Chisholm S. W. , Stross Raymond G. , Nobbs Paul A. 
Published: August 2007

SUMMARY Eugene gracilis Klebs (Z) was grown in a cyclostat (continuous culture on a light/dark cycle) at growth limiting levels of phosphate. Cell division was restricted to the dark period regardless of the proportion of the cells dividing during each 24 h period. Growth rate, as reflected by the amplitude of the cell density oscillation, was correlated with dilution rate. The width of the division gate was analyzed using a phasing index and found to be narrowest at dilution rates where the mean generation time of the cell population was an even multiple of 24 h. The effect was attributed to enhanced phasing of the cell division process by the biological clock of Euglena.Residual phosphate levels in the cyclostat were less than 0.3 μM PO4 at all submaximal growth rates. Cellular phosphorus concentration increased with dilution rate as described by a hyperbola saturating at Dmax= 0.74 day−1 with 8 × 10−8μM P/cell as the minimum intracellular phosphorus concentration for growth.The results are discussed, in terms of the inherent similarities and differences between a cyclostat and a steady state chemostat, and the advantages of the cyclostat for studies in phytoplankton ecology.
DIATOM COMMUNITIES FROM A DELAWARE SALT MARSH 1,2
Authors: Sullivan Michael J. 
Published: August 2007

SUMMARYEdaphic diatoms were collected from 5 representative habitats of Canary Creek salt marsh, Lewes, Delaware, from 24 July 1969 to 21 July 1970. Of the 104 taxa encountered, 32 had a general distribution on the marsh and 41 were endemic to one of the 5 habitats sampled. Three of the habitats supported stands of grasses: tall Spartina alterniflora Loisel., dwarf S. alterniflora, and Distichlis spicata (L.) Greene; and these habitats possessed the highest species diversity (H') and the greatest number of diatom species. The remaining 2 habitats, a bare bank and a panne, were devoid of macroscopic vegetation. The diatoms of these last 2 habitats were exposed to hypersaline conditions during warmer periods of the year and this was considered a contributing factor to the lower values observed for the aforementioned parameters of community structure. A comprehensive examination of the community structure characterizing the 5 habitats, employing statistical analyses and the distribution of species, showed each habitat to support its own unique and easily recognizable edaphic diatom community. A multiple regression analysis indicated that the differences between the 5 communities were closely related to differences in temperature and elevation between the habitats, and also a result of significant interactions between edaphic diatoms and filamentous algae.
MORPHOLOGY OF PLACENTOPHORA (SOLIERIACEAE, GIGARTINALES: RHODOPHYTA), A NEW GENUS BASED ON SARCODIOTHECA COLENSOI FROM NEW ZEALAND1
Authors: Kraft Gerald T. 
Published: August 2007

SUMMARYThe only member of the red algal family Solieriaceae known from New Zealand is the endemic Sarcodiotheca colensoi (Hook. & Harv.) Kylin. This study shows that it differs in several respects from the type S. furcata (Setch. & Gard.) Kylin; thus a new genus Placentophora is created for the New Zealand alga. Although P. colensoi nov. comb. is retained in the Solieriaceae on the basis of vegetative, spermatangial, tetrasporangial, carpogonial‐branch and early gonimoblast features, it differs from typical members of that family in its pattern of later carposporophyte development. After a single gonimoblast initial is cut off from the auxiliary cell towards the center of the thallus, further gonimoblasts develop from the initial as ramifying, radiating filaments. These filaments enter an extensive “nutritive‐cell” region surrounding the auxiliary cell, form, numerous connections to the “nutritive” cells, and incorporate most of them into a central placenta of interconnected, and variously‐fused vegetative and gonimoblast cells. Carpo‐sporangia then form in short chains around the periphery of the placenta. The cystocarp lacks both a central fusion cell and a sterile‐celled investment, or “Faserhülle.” The distinctive carposporophyte of Placentophora is compared to patterns of gonimoblast development, known in other members of the Solieriaceae.
CULTURE AND HYBRIDIZATION STUDIES ON PETROCELIS (RHODOPHYTA) FROM ALASKA AND CALIFORNIA1,2
Authors: Polanshek Alan R. , West John A. 
Published: August 2007

SUMMARYCultured tetraspores of Petrocelis middendorffii (Ruprecht) Kjellman from Amchitka Island, Alaska, gave rise to foliose, dioecious gametophytes similar to cultured gametophytes of P. franciscana Setchell & Gardner. A 1:1 ratio male:female gametophytes was obtained. Fertilized female plants produced cystocarps and carpospores that gave rise to crustose plants anatomically similar to field‐collected Petro‐celis sporophytes. Cultured male gametophytes of P. middendorffii were interfertile with cultured female blades of field‐collected Gigartina pacifica Kjellman. Cultured P. middendorffii gametophytes from Amchitka were interfertile with cultured gametophytes of P. franciscana from 2 localities in California. Hybrid carpospores gave rise to crustose sporophytes that have not reproduced. Anatomical comparisons of P. middendorffii from Amchitka with P. franciscana from California showed no important differences in the characters originally used to separate these species. The interfertility of cultured Petrocelis gametophytes from california and Amchitka as well as the similarities of the history and anatomy suggests that a single species is involved. P. franciscana is reduced to a synonym of P. middendorfii.
ULTRASONIC REMOVAL OF EPILITHIC ALGAE IN A BAR‐CLAMP SAMPLER1,2
Authors: Gale William F. 
Published: August 2007

SUMMARYA bar clamp with a collecting cup attached was used to collect epilithic algae samples on stones 4–50 cm diam.; stones were sampled by wading in shallow water and by SCUBA diving in deep water. The collecting cup delimits the sampling area (a 22 mm diam. circle) for cleaning and protects it from cell loss and desiccation. On some stones, ultrasonic vibration removed large numbers of cells (up to 62% of the total) missed by scraping and brushing.
Enhanced Survival and Cure of F98 Glioma–Bearing Rats following Intracerebral Delivery of Carboplatin in Combination with Photon Irradiation
Authors: Rousseau Julia , Boudou Caroline , Barth Rolf F. , Balosso Jacques , Estève François , Elleaume Hélène 
Published: August 2007

Abstract
Purpose: The goal of the present study was to evaluate the efficacy of intracerebral (i.c.) administration of carboplatin by means of convection-enhanced delivery (CED) in combination with fractionated, external beam photon irradiation for the treatment of F98 glioma–bearing rats.
Experimental Design: Carboplatin (20 μg/20 μL) was administrated i.c. by CED to F98 glioma–bearing rats, 13 days after stereotactic implantation of 103 tumor cells. One day following initiation of CED, a 24-Gy X-ray dose was administered in three daily fractions of 8 Gy each. Photon irradiation was carried out using either a conventional (6 MV) linear accelerator or a monochromatic synchrotron source (80 keV) at the European Synchrotron Radiation Facility. The primary end point of this study was overall survival.
Results: The median survival times were 79 and 60 days and the corresponding percent increase in life spans were 182% and 114%, respectively, for the combination of carboplatin chemotherapy and irradiation with either 6-MV or 80-keV photons. A subset of long-term survivors (&gt;200 days) were observed in both chemoradiotherapy groups: 16.6% and 8.3% for 6 MV and 80 keV, respectively. In contrast, the median survival times for 6-MV or 80-keV irradiated controls, chemotherapy alone, and untreated controls were 42, 51, 45, and 28 days, respectively.
Conclusions: Our results convincingly show the therapeutic efficacy of i.c. administration of carboplatin by means of CED in combination with either 6-MV or 80-keV photons. Further studies are warranted to optimize this combination of chemoradiotherapy for malignant gliomas.
Toxic epidermal necrolysis-like acute cutaneous lupus erythematosus
Authors: Paradela S. , Martínez-Gómez W. , Fernández-Jorge B. , Castiñeiras I. , Yebra-Pimentel T. , Llinares P. , Fonseca Capdevila E. 
Published: August 2007

The term `Acute Syndrome of Apoptotic Pan-Epidermolysis' (ASAP) designs clinical entities characterized by massive cleavage of the epidermis resulting from hyperacute epidermal basal cell apoptotic injury. It can be seen typically in classic toxic epidermal necrolysis (TEN), but occasionally occurs in non-dru1g-induced entities called `TEN-like' diseases (e.g., lupus erythematosus (LE), acute graft versus host disease and pseudoporphyria). We would like to highlight the difficulties of establishing differential diagnoses between `TEN-like' LE and drug reactions, especially when LE has not been previously diagnosed. We report a patient with fulminate pattern of epidermal cell injury resulting in a clinical presentation having combined features of drug-induced TEN and acute cutaneous LE with laboratory findings of systemic LE (SLE) and without systemic symptoms or high-risk drug ingestion. Although most cases of ASAP in the setting of LE are drug-induced TEN, there are reported cases of `TEN-like' LE with subacute progression, absence of systemic involvement and lack of drug ingestion. Such cases usually have a previous history of SLE and positive serologic markers. Although some authors observed that these lesions could be related to systemic severity of SLE, this is the first patient reported who progresses to discoid LE and we think it could be a marker of good prognosis. Lupus (2007) 16, 741—745.
Zebrafish as a model for defining the functional impact of mammalian ferroportin mutations
Authors: De Domenico Ivana , Vaughn Michael B. , Yoon Donghoon , Kushner James P. , Ward Diane M. , Kaplan Jerry 
Published: August 2007

AbstractThe term hemochromatosis represents a group of inherited disorders leading to iron overload. Mutations in HFE, HJV, and TfR2 cause autosomal-recessive forms of hemochromatosis. Mutations in ferroportin, however, result in dominantly inherited iron overload. Some mutations (H32R and N174I) in ferroportin lead to macrophage iron loading, while others (NI44H) lead to hepatocyte iron loading. Expression of H32R or N174I ferroportin cDNA in zebrafish leads to severe iron-limited erythropoiesis. Expression of wild-type ferroportin or hepcidin-resistant ferroportin (N144H) does not affect erythropoiesis. Zebrafish provides a facile way of identifying which ferroportin mutants may lead to macrophage iron loading.
Tissue factor activation: is disulfide bond switching a regulatory mechanism?
Authors: Pendurthi Usha R. , Ghosh Samit , Mandal Samir K. , Rao L. Vijaya Mohan 
Published: August 2007

AbstractA majority of tissue factor (TF) on cell surfaces exists in a cryptic form (ie, coagulation function inactive) but retains its functionality in cell signaling. Recent studies have suggested that cryptic TF contains unpaired cysteine thiols and that activation involves the formation of the disulfide bond Cys186-Cys 209 and that protein disulfide isomerase (PDI) regulates TF coagulant and signaling activities by targeting this disulfide bond. This study was carried out to investigate the validity of this novel concept. Although treatment of MDA 231 tumor cells, fibroblasts, and stimulated endothelial cells with the oxidizing agent HgCl2 markedly increased the cell-surface TF coagulant activity, the increase is associated with increased anionic phospholipids at the cell surface. Annexin V, which binds to anionic phospholipids, attenuated the increased TF coagulant activity. It is noteworthy that treatment of cells with reducing agents also increased the cell surface TF activity. No evidence was found for either detectable expression of PDI at the cell surface or association of TF with PDI. Furthermore, reduction of PDI with the gene silencing had no effect on either TF coagulant or cell signaling functions. Overall, the present data undermine the recently proposed hypothesis that PDI-mediated disulfide exchange plays a role in regulating TF procoagulant and cell signaling functions.
PERK eIF2 alpha kinase is required to regulate the viability of the exocrine pancreas in mice
Authors: Iida Kaori , Li Yulin , McGrath Barbara C , Frank Ami , Cavener Douglas R 
Published: August 2007

Abstract

Background
Deficiency of the PERK eIF2α kinase in humans and mice results in postnatal exocrine pancreatic atrophy as well as severe growth and metabolic anomalies in other organs and tissues. To determine if the exocrine pancreatic atrophy is due to a cell-autonomous defect, the Perk gene was specifically ablated in acinar cells of the exocrine pancreas in mice.

Results
We show that expression of PERK in the acinar cells is required to maintain their viability but is not required for normal protein synthesis and secretion. Exocrine pancreatic atrophy in PERK-deficient mice was previously attributed to uncontrolled ER-stress followed by apoptotic cell death based on studies in cultured fibroblasts. However, we have found no evidence for perturbations in the endoplasmic reticulum or ER-stress and show that acinar cells succumb to a non-apoptotic form of cell death, oncosis, which is associated with a pronounced inflammatory response and induction of the pancreatitis stress response genes. We also show that mice carrying a knockout mutation of PERK's downstream target, ATF4, exhibit pancreatic deficiency caused by developmental defects and that mice ablated for ATF4's transcriptional target CHOP have a normal exocrine pancreas.

Conclusion
We conclude that PERK modulates secretory capacity of the exocrine pancreas by regulating cell viability of acinar cells.
Expression patterns of semaphorin7A and plexinC1during rat neural development suggest roles in axon guidance and neuronal migration
Authors: Pasterkamp R Jeroen , Kolk Sharon M , Hellemons Anita JCGM , Kolodkin Alex L 
Published: August 2007

Abstract
Background
Although originally identified as embryonic axon guidance cues, semaphorins are now known to regulate multiple, distinct, processes crucial for neuronal network formation including axon growth and branching, dendritic morphology, and neuronal migration. Semaphorin7A (Sema7A), the only glycosylphosphatidylinositol-anchored semaphorin, promotes axon growth in vitro and is required for the proper growth of the mouse lateral olfactory tract in vivo. Sema7A has been postulated to signal through two unrelated receptors, an RGD-dependent α1β1-integrin and a member of the plexin family, plexinC1. β1-integrins underlie Sema7A-mediated axon growth and Sema7A function in the immune system. Sema7A-plexinC1 interactions have also been implicated in immune system function, but the neuronal role of this ligand-receptor pair remains to be explored. To gain further insight into the function(s) of Sema7A and plexinC1 during neural development, we present here a detailed analysis of Sema7A and plexinC1 expression in the developing rat nervous system.

Results
In situ hybridization revealed select expression of Sema7A and plexinC1 in multiple neuronal systems including: the olfactory system, the hypothalamo-hypophysial system, the hippocampus, the meso-diencephalic dopamine system, and the spinal cord. Within these systems, Sema7A and plexinC1 are often expressed in specific neuronal subsets. In general, Sema7A transcript levels increase significantly towards adulthood, whereas plexinC1 expression decreases as development proceeds.
PlexinC1, but not Sema7A, is strongly expressed by distinct populations of migrating neurons. In addition to neuronal expression, Sema7A and plexinC1 transcripts were detected in oligodendrocytes and ependymal cells, respectively.

Conclusion
Sema7A and plexinC1 expression patterns are consistent with these proteins serving both cooperative and separate functions during neural development. The prominent expression of plexinC1 in several distinct populations of migrating neurons suggests a novel role for this plexin family member in neuronal migration.
Thyroid hormone receptor orthologues from invertebrate species with emphasis on Schistosoma mansoni
Authors: Wu Wenjie , Niles Edward G , LoVerde Philip T 
Published: August 2007

Abstract

Background:
Thyroid hormone receptors (TRs) function as molecular switches in response to thyroid hormone to regulate gene transcription. TRs were previously believed to be present only in chordates.

Results:
We isolated two TR genes from the Schistosoma mansoni and identified TR orthologues from other invertebrates: the platyhelminths, S. japonium and Schmidtea mediterranea, the mollusc, Lottia gigantean and the arthropod Daphnia pulex. Phylogenetic analysis of the DNA binding domain and/or ligand binding domain shows that invertebrate and vertebrate TRs cluster together, TRs from the vertebrates and from the jawless vertebrate (lamprey) clustered within separate subgroups, Platyhelminth TRs cluster outside of the vertebrate TR subgroups and that the schistosome TRs and S. mediterranea TRs clustered within separate subgroups.
Alignment of the C-terminus of the A/B domain revealed a conserved TR-specific motif, termed TR 'N-terminus signature sequence', with a consensus sequence of (G/P)YIPSY(M/L)XXXGPE(D/E)X.
Heterodimer formation between S. mansoni TRs and SmRXR1 suggests that the invertebrate TR protein gained the ability to form a heterodimer with RXR. ESMA analysis showed that SmTRα could bind to a conserved DNA core motif as a monomer or homodimer.

Conclusion:
Vertebrate TR genes originated from a common ancestor of the Bilateria. TR genes underwent duplication independently in the Protostomia and Deuterostomia. The duplication of TRs in deuterostomes occurred after the split of jawless and jawed vertebrates. In protostomes, TR genes underwent duplication in Platyhelminths, occurring independently in trematode and turbellarian lineages. Using S. mansoni TRs as an example, invertebrate TRs exhibited the ability to form a dimer with RXR prior to the emergence of the vertebrate TRs and were able to bind to vertebrate TR core DNA elements as a monomer or homodimer.