bluuebunny/crossref_metadata_2025 huggingface dataset:
Lack and restoration of sensitivity of lung cancer cells to cellular attack with special reference to expression of human leukocyte antigen class I and/or major histocompatibility complex class I chain related molecules A/B
Authors: Baba Tetsuro , Hanagiri Takeshi , Ichiki Yoshinobu , Kuroda Koji , Shigematsu Yoshiki , Mizukami Makiko , Sugaya Masakazu , Takenoyama Mitsuhiro , Sugio Kenji , Yasumoto Kosei
Published: August 2007

Both cytotoxic T lymphocytes (CTL) and natural killer (NK) cells may play major roles in the host defense against cancer. However, their relationship against the same tumor remains to be elucidated. Among 26 human lung cancer cell lines established in our laboratory, 10 (38%) exhibited human leukocyte antigen (HLA)‐class I haplotype loss and three (12%) lost HLA‐class I expression totally by flow cytometry analysis. The two cell lines (E522L and C831L) that lost their expression of HLA‐class I in vitro and in vivo were applied for further evaluations. Genetic abnormalities of β2‐microglobulin gene were observed in both E522L (loss of mRNA) and C831L (point mutation). Transduction of the wild‐type β2‐microglobulin gene rendered them positive for HLA‐class I expression. The CTL were induced from autologous peripheral blood mononuclear cells or regional lymph node lymphocytes by stimulation with wild‐type β2‐microglobulin transduced‐E522L or ‐C831L, and they showed tumor‐specific cytotoxicity against wild‐type β2‐microglobulin‐transductant, but not parental cells. In NK cell cytotoxicity, E522L showed high sensitivity to NK cells; however, C831L showed resistance despite loss of HLA‐class I expression. E522L expressed MHC class I chain related molecules A/B, but C831L did not. The transduction of the MHC class I chain related molecule A gene from E522L rendered C831L positive for expression and sensitive to NK cell cytotoxicity. Reconstruction of HLA‐class I and MHC class I chain related molecules A expression could abrogate evasion from cellular attack by CTL and NK cells, and it may lead to a breakthrough in the development of cancer immunotherapy. (Cancer Sci 2007; 98: 1795–1802)
Recklessness as a hallmark of aggressive cancer
Authors: Noda Makoto , Takahashi Chiaki
Published: August 2007

Cancer recurrence after surgical treatment is a major concern for patients and doctors. Understanding what makes tumors prone to recurrence would be an important step toward its prevention. Accumulating evidence indicates that the level of membrane‐associated protease regulator reversion‐inducing cysteine‐rich protein with Kazal motifs (RECK) expressed in tumor tissue is a good prognostic indicator in several common cancers. Certain members of the matrix metalloproteinase family are often upregulated in advanced cancers and are known to play important roles in tumor angiogenesis, invasion and metastasis. RECK negatively regulates several matrix metalloproteinases. Therefore, RECK itself may well be considered a promising tool or target molecule to be activated in cancer therapy. Here we review the recent advances in RECK research and discuss some of the important issues to be addressed in future studies. (Cancer Sci 2007; 98: 1659–1665)
Up‐regulation of CD147 and matrix metalloproteinase‐2, ‐9 induced by P‐glycoprotein substrates in multidrug resistant breast cancer cells
Authors: Li Qing‐Quan , Wang Wen‐Juan , Xu Jing‐Da , Cao Xi‐Xi , Chen Qi , Yang Jin‐Ming , Xu Zu‐De
Published: August 2007

Treatment of animals bearing multidrug resistant (MDR) tumor cells with P‐glycoprotein (P‐gp) substrates could worsen host survival. It is assumed that this is due to increased tumor metastasis. To clarify the mechanism(s) underlying this observation, the MDR human breast cancer cell line, MCF‐7/AdrR, and its sensitive parental line, MCF‐7, was treated with various concentrations of P‐gp substrate drugs (vincristine, paclitoxel, adriamycin) and a P‐gp non‐substrate drug (bleomycin) in serum‐free media. Increased production of CD147, and matrix metalloproteinases (MMP)‐2, ‐9 was observed only in MDR cancer cells exposed to P‐gp substrates, as determined using real‐time polymerase chain reaction, western blotting and zymography. Correspondingly, P‐gp substrates significantly enhanced the in vitro invasion abilities of MCF‐7/Adr cells. It was also found that the drug‐induced promotion of CD147, and MMP‐2, ‐9 was consistent with increased expression of epidermal growth factor receptor (EGFR) and that inhibition of either EGFR or P‐gp activity could significantly interrupt the downstream effects, and so inhibit in vitro invasion abilities motivated by P‐gp substrates. These results imply that treatment of MDR tumors with P‐gp substrates could adversely affect therapeutic outcomes through modulating the production of CD147, MMP‐2, ‐9, and EGFR, and suggest that this effect may be initiated by the transporter function of P‐gp. (Cancer Sci 2007; 98: 1767–1774)
Induction of MHC class I molecule cell surface expression and epigenetic activation of antigen‐processing machinery components in a murine model for human papilloma virus 16‐associated tumours
Authors: Manning Jasper , Indrova Marie , Lubyova Barbora , Pribylova Hana , Bieblova Jana , Hejnar Jiri , Simova Jana , Jandlova Tana , Bubenik Jan , Reinis Milan
Published: August 2007

Epigenetic events play an important role in tumour progression and also contribute to escape of the tumour from immune surveillance. In this study, we investigated the up‐regulation of major histocompatibility complex (MHC) class I surface expression on tumour cells by epigenetic mechanisms using a murine tumour cell line expressing human E6 and E7 human papilloma virus 16 (HPV16) oncogenes and deficient in MHC class I expression, as a result of impaired antigen‐presenting machinery (APM). Treatment of the cells with the histone deacetylase inhibitor Trichostatin A, either alone or in combination with the DNA demethylating agent 5‐azacytidine, induced surface re‐expression of MHC class I molecules. Consequently, the treated cells became susceptible to lysis by specific cytotoxic T lymphocytes. Further analysis revealed that epigenetic induction of MHC class I surface expression was associated with the up‐regulation of APM genes [transporter associated with antigen processing 1 (TAP‐1), TAP‐2, low‐molecular‐mass protein 2 (LMP‐2) and LMP‐7]. The results demonstrate that expression of the genes involved in APM are modulated by epigenetic mechanisms and suggest that agents modifying DNA methylation and/or histone acetylation have the potential to change the effectiveness of antitumour immune responses and therapeutically may have an impact on immunological output.
A white light confocal microscope for spectrally resolved multidimensional imaging
Authors: FRANK J. H. , ELDER A. D. , SWARTLING J. , VENKITARAMAN A. R. , JEYASEKHARAN A. D. , KAMINSKI C. F.
Published: August 2007

Spectrofluorometric imaging microscopy is demonstrated in a confocal microscope using a supercontinuum laser as an excitation source and a custom‐built prism spectrometer for detection. This microscope system provides confocal imaging with spectrally resolved fluorescence excitation and detection from 450 to 700 nm. The supercontinuum laser provides a broad spectrum light source and is coupled with an acousto‐optic tunable filter to provide continuously tunable fluorescence excitation with a 1‐nm bandwidth. Eight different excitation wavelengths can be simultaneously selected. The prism spectrometer provides spectrally resolved detection with sensitivity comparable to a standard confocal system. This new microscope system enables optimal access to a multitude of fluorophores and provides fluorescence excitation and emission spectra for each location in a 3D confocal image. The speed of the spectral scans is suitable for spectrofluorometric imaging of live cells. Effects of chromatic aberration are modest and do not significantly limit the spatial resolution of the confocal measurements.
Cryo‐FIB‐nanotomography for quantitative analysis of particle structures in cement suspensions
Authors: HOLZER L. , GASSER PH. , KAECH A. , WEGMANN M. , ZINGG A. , WEPF R. , MUENCH B.
Published: August 2007

Cryo‐FIB‐nanotomography is a novel high‐resolution 3D‐microscopy technique, which opens new possibilities for the quantitative microstructural analysis of complex suspensions. In this paper, we describe the microstructural changes associated with dissolution and precipitation processes occurring in a fresh cement paste, which has high alumina and sulphate contents. During the first 6 min, precipitation of ettringite leads to a general decrease of the particle size distribution. In the unhydrated cement paste almost no particles smaller than 500 nm are present, whereas after 6 min this size class already represents 9 vol%. The precipitation of ettringite also leads to a significant increase of the particle number density from 0.294*109/mm3 at t0min to 20.55*109/mm3 at t6min. Correspondingly the surface area increases from 0.75 m2/g at t0min to 2.13 m2/g at t6min. The small ettringite particles tend to form agglomerates, which strongly influence the rheological properties. The particular strength of cryo‐FIB‐nt is the potential to quantify particle structures in suspension and thereby also to describe higher‐order topological features such as the particle–particle interfaces, which is important for the study of agglomeration processes.
AFM investigation of Martian soil simulants on micromachined Si substrates
Authors: VIJENDRAN S. , SYKULSKA H. , PIKE W. T.
Published: August 2007

The micro and nanostructures of Martian soil simulants with particles in the micrometre‐size range have been studied using a combination of optical and atomic force microscopy (AFM) in preparation for the 2007 NASA Phoenix Mars Lander mission. The operation of an atomic force microscope on samples of micrometre‐sized soil particles is a poorly investigated area where the unwanted interaction between the scanning tip and loose particles results in poor image quality and tip contamination by the sample. In order to mitigate these effects, etched silicon substrates with a variety of features have been used to facilitate the sorting and gripping of particles. From these experiments, a number of patterns were identified that were particularly good at isolating and immobilizing particles for AFM imaging. This data was used to guide the design of micromachined substrates for the Phoenix AFM. Both individual particles as well as aggregates were successfully imaged, and information on sizes, shapes and surface morphologies were obtained. This study highlights both the strengths and weaknesses of AFM for the potentialin situinvestigation of Martian soil and dust. Also presented are more general findings of the limiting operational constraints that exist when attempting the AFM of high aspect ratio particles with current technology. The performance of the final designs of the substrates incorporated on Phoenix will be described in a later paper.
Quasi‐cleavage fracture planes in spheroidized A533B steel
Authors: KUMAR A. , WILKINSON A. J. , ROBERTS S. G.
Published: August 2007

Electron backscattered diffraction (EBSD) has been used to acquire crystal orientation information around unusual microcracks induced by tensile deformation of notched specimens of spheroidized A533B steel. This unusual fracture mode has been called quasi‐cleavage and occurs at relatively low temperatures with fracture energies below that of the upper shelf. EBSD measurements on sectioned samples showed that the quasi‐cleavage cracks were intragranular. A two‐dimensional analysis technique was used in which EBSD measured crystal orientations were combined with secondary electron imaging to obtain the trace of the crack facet on the section plane. The measurements revealed that the observed crack facets were consistent with crack propagation along the {001} and {011} planes.
Accuracy of orientation distribution function determination based on EBSD data‐A case study of a recrystallized low alloyed Zr sheet
Authors: BOZZOLO N. , GERSPACH F. , SAWINA G. , WAGNER F.
Published: August 2007

The question of the statistical accuracy of EBSD data for global texture calculation was re‐explored on the basis of a very large grain population (83 000 grains measured on a recrystallized low‐alloyed Zr sheet). Previous works aimed mainly at identifying and quantifying the main texture components and were based on much smaller data sets. The present work attempts to quantify the accuracy of the complete texture, including low‐density regions of the orientation space. For that purpose, a new statistical parameter, VΔ, based on the calculation of texture difference functions is proposed. This parameter has two main advantages: it is equally sensitive to both high and low peaks of the orientation density function (ODF), and it has a physical interpretation because it is the material volume fraction corresponding to the difference between a given ODF and a reference ODF (considered, or known to be close to the truth). Two main variables were studied: the number of grains taken into account and the peak width ϕ0 of Bunge's ‘Gaussian’ model density used as kernel for the actual analysis. The orientation distribution functions were computed by nonparametric kernel density estimation with harmonics up to the order of 34. Minimizing the value of VΔ serves as the objective function for optimizing the peak width ϕ0 as a function of the number of grains. The properties of the VΔ parameter also allows for the definition of a method for estimating the accuracy of a given texture that has been obtained from a limited number of grains, without knowing the true texture of the investigated material.
Determination of parent orientation maps in advanced titanium‐based alloys
Authors: GERMAIN L. , DEY S. R. , HUMBERT M. , GEY N.
Published: August 2007

In the past few years, reconstruction methods have been developed and applied successfully to restore the β microtexture in titanium alloys. This contribution shows how these methods are extended to other transformations often encountered in advanced titanium alloys: the α (hcp)→γ (tetragonal) and the β (bcc)→O (orthorhombic) transformation.

The efficiency of the restitution depends on specific crystallographic features of the investigated phase transformations. Therefore, the paper outlines these crystallographic specificities for some advanced titanium alloys. To illustrate the capability of the method to reconstruct the parent phase, different restored parent microtextures of these alloys are presented. The results show that the reconstruction methods are an efficient tool to study the microstructure and texture modifications induced by these phase transformations.
The preferred CSL misorientation distribution in polycrystalline SrTiO3
Authors: PARK MYUNG‐BEOM , SHIH SHAO‐JU , COCKAYNE DAVID J. H.
Published: August 2007

Electron backscattered diffraction is used to investigate the preferred CSL (coincidence site lattice) distribution of polycrystalline SrTiO3 as a function of annealing times (1 h and 16 h). Comparison of the CSL misorientations suggests that the CSL boundary energy plays a role in the preferred grain growth.
Neuroepithelial stem cells differentiate into neuronal phenotypes and improve intestinal motility recovery after transplantation in the aganglionic colon of the rat
Authors: Liu W. , Wu R. D. , Dong Y. L. , Gao Y. M.
Published: August 2007

Abstract  The purpose of this study was to elucidate the possibility and the biological significance of intracolonic grafting of neuroepithelial stem cells (NESCs) as a therapeutic strategy for neuronal replacement in disorders of the enteric nervous system (ENS) such as aganglionosis. The enteric plexus of rat colon were eliminated by serosal application of the cationic surfactant benzalkonium chloride. NESCs were harvested from the neural tube of embryonic rat, labelled with bromodeoxyuridine (BrdU), and transplanted into the denervated colon. After 2, 4 and 8 weeks, grafted cells were visualized in colon sections by fluorescent double‐staining for BrdU and neuronal, astrocytic, neurochemical or stem cell markers. Eight weeks post‐transplantation, the intestinal motility was assessed by measuring the changes of intraluminal pressure responding to inflating stimulation and the responses to electrical field stimulation (EFS). Our results indicate that when transplanted into the denervated gut, NESCs survived and could differentiate into neurons and glial cells in vivo. Furthermore, inflation stimulated contraction and EFS‐induced response were observed in NESCs grafted group compared with no reaction in denervated group. Therefore, NESCs can survive and function in the denervated rat colon in vivo, which indicates that NESCs provide a promising cellular replacement candidate for ENS.
Species dependent differences in the actions of sympathetic nerves and noradrenaline in the internal anal sphincter
Authors: Cobine C. A. , Fong M. , Hamilton R. , Keef K. D.
Published: August 2007

Abstract Excitatory motor innervation to the internal anal sphincter (IAS) of the monkey, the rabbit and mouse were compared. Contractile responses to electrical field stimulation of nerves (EFS, atropine 1 μmol L−1andN(ω)‐nitro‐l‐arginine 100 μmol L−1present throughout) were examined in isolated strips of IAS. In the monkey IAS, EFS caused frequency dependent (1–30 Hz) contractions which were abolished by guanethidine (10 μmol L−1) or phentolamine (3 μmol L−1). The sympathetic neurotransmitter noradrenaline (NA) also caused concentration‐dependent (10 nmol L−1–100 μmol L−1) contractions which were abolished by phentolamine revealing a small relaxation that was abolished by propranolol (3 μmol L−1). In contrast, EFS caused only relaxation of the mouse and rabbit IAS which was not affected by guanethidine. Furthermore, NA relaxed these muscles and relaxation was nearly abolished by combined addition of phentolamine and propranolol. In conclusion, the monkey IAS is functionally innervated by sympathetic nerves that contract the muscle via excitatoryα‐adrenergic receptors. In contrast, no significant motor function could be identified for sympathetic nerves in the rabbit or mouse IAS although adrenergic receptors linked to muscle inhibition are present. These data reveal species dependent differences in sympathetic motor innervation and suggest that some species are more appropriate than others as models for motor innervation to the human IAS.
Effects of neurotrophin 3 on gastric and colonic motility in awake rats
Authors: Kueper M. A. , Meile T. , Zittel T. T. , Konigsrainer A. , Glatzle J.
Published: August 2007

Abstract  Neurotrophin 3 (NT3) and its receptors are expressed throughout the gastrointestinal tract, especially in the enteric nervous system. However, little is known about the effects of NT3 on gastrointestinal motility. To investigate the effects of NT3 on gastric or colonic motility under baseline conditions, after subdiaphragmatic vagotomy and in a model of postoperative ileus. Sprague–Dawley rats were equipped with strain gauge transducers on the gastric or colonic wall. Motility was recorded for 30 min, followed by i.v. administration of NT3 and motility‐recording for another 60 min. Experiments were performed on three consecutive days and separately in a postoperative ileus model. To evaluate a vagal pathway, experiments were also performed on vagotomized rats. NT3 inhibited gastric motility. This inhibitory effect was reduced by subdiaphragmatic vagotomy. Preoperative treatment with NT3 prolonged the postoperative gastric ileus compared to vehicle treatment. Colonic motility in the intact animal was unchanged by NT3, but was increased postoperatively. NT3 treatment inhibited gastric but not colonic motility. This inhibition of gastric motility seems to be partly mediated by the vagus nerve. NT3 aggravates gastric postoperative ileus but attenuates colonic postoperative ileus, which corresponds to the observed positive effects of NT3 on constipated patients.
Kynurenic acid inhibits intestinal hypermotility and xanthine oxidase activity during experimental colon obstruction in dogs
Authors: Kaszaki J. , Palásthy Z. , érczes D. , Rácz A. , Torday C. , Varga G. , Vécsei L. , Boros M.
Published: August 2007

Abstract  Kynurenic acid (KynA), an endogenous antagonist of N‐methyl‐d‐aspartate (NMDA) glutamate receptors, protects the central nervous system in excitotoxic neurological diseases. We hypothesized that the inhibition of enteric glutamate receptors by KynA may influence dysmotility in the gastrointestinal tract. Group 1 of healthy dogs served as the sham‐operated control, in group 2, the animals were treated with KynA, while in groups 3 and 4 mechanical colon obstruction was maintained for 7 h. Group 4 was treated with KynA at the onset of ileus. Hemodynamics and motility changes were monitored, and the activities of xanthine oxidoreductase (XOR) and myeloperoxidase (MPO) were determined from tissue samples. Colon obstruction induced a hyperdynamic circulatory reaction, significantly elevated the motility index and increased the mucosal leucocyte accumulation and the XOR activity. The KynA treatment augmented the tone of the colon, permanently decreased the motility index of the giant colonic contractions and reduced the increases in XOR and MPO activities. These effects were concomitant with the in vitroinhibition of XOR activity. In conclusion, KynA antagonizes the obstruction‐induced motility responses and XOR activation in the colon. Inhibition of enteric NMDA receptors may provide an option to influence intestinal hypermotility and inflammatory changes.
NONPARAMETRIC REGRESSION ON FUNCTIONAL DATA: INFERENCE AND PRACTICAL ASPECTS
Authors: Ferraty Frédéric , Mas André , Vieu Philippe
Published: August 2007

We consider the problem of predicting a real random variable from a functional explanatory variable. The problem is tackled using a nonparametric kernel approach, which has been recently adapted to this functional context. We derive theoretical results from a deep asymptotic analysis of the behaviour of the estimate, including mean squared convergence (with rates and precise evaluation of the constant terms) as well as asymptotic distribution. Practical use of these results relies on the ability to estimate these constants. Some perspectives in this direction are discussed. In particular, a functional version of wild bootstrapping ideas is proposed and used both on simulated and real functional datasets.
SEMIPARAMETRIC ESTIMATION OF THE ERROR DISTRIBUTION IN MULTIVARIATE REGRESSION USING COPULAS
Authors: Kim Gunky , Silvapulle Mervyn J. , Silvapulle Paramsothy
Published: August 2007

A semiparametric method is developed to estimate the dependence parameter and the joint distribution of the error term in the multivariate linear regression model. The nonparametric part of the method treats the marginal distributions of the error term as unknown, and estimates them using suitable empirical distribution functions. Then the dependence parameter is estimated by either maximizing a pseudolikelihood or solving an estimating equation. It is shown that this estimator is asymptotically normal, and a consistent estimator of its large sample variance is given. A simulation study shows that the proposed semiparametric method is better than the parametric ones available when the error distribution is unknown, which is almost always the case in practice. It turns out that there is no loss of asymptotic efficiency as a result of the estimation of regression parameters. An empirical example on portfolio management is used to illustrate the method.
A Global Alliance against Forced Labour? Unfree Labour, Neo‐Liberal Globalization and the International Labour Organization
Authors: LERCHE JENS
Published: August 2007

The ILO is presently attempting to spearhead a ‘global alliance against forced labour’. This article surveys the ILO approach to forced labour, recent theoretical debates regarding forced labour and recent empirical work on bonded labour in India. It argues that the ILO ‘ghettoizes’ forced labour, and that existing theories do not provide an alternative to this, as they focus on high‐level ahistorical models. There is a need to develop specific analyses of the processes underlying both free and unfree labour relations in the present context, and their relation to neo‐liberal globalization as well as country‐specific conditions. The review of Indian case studies and of aspects of neo‐liberal globalization points towards such an analytical approach.
Stories of Rural Accumulation in Africa: Trajectories and Transitions among Rural Capitalists in Senegal
Authors: OYA CARLOS
Published: August 2007

This paper analyzes primary qualitative evidence from life histories of rural capitalists in contemporary Senegal. Various common themes in the declining literature on rural capitalism in Africa are discussed with reference to the specific individual trajectories of rural farm capitalists in Senegal. The themes include the emergence of rural capitalism in the context of protracted, uneven and gradual rural social differentiation and the various processes that have accompanied it; the condition of ‘entrepreneurship’ in such changing historical contexts; the symbiotic relationship between different spaces (loci) of accumulation, especially trade, transport and farming and the historical context in which they take place; the crucial but sometimes contradictory role of the state in spurring or constraining rural capitalist accumulation; and the variety of ‘idioms of accumulation’, which reflect transitions and synthesis between non‐capitalist and capitalist forms of labour surplus appropriation at the level of individual capitalists, despite some uniformity in the general logic of capital and the spread of capitalist relations of production and exchange. The paper also discusses the methodological power and limitations of oral narratives as a method to gather evidence on long‐term processes of agrarian change and accumulation in rural Africa. Finally, the life histories shed some light on the origins of rural capitalists and show that there is a combination of instances of ‘capitalism from above’ and ‘from below’ but that no dominant pattern can be clearly discerned at least in the space of one or two generations.
BIOCHEMICAL COMPOSITION AND PHOTOSYNTHETIC CARBON METABOLISM OF NUTRIENT LIMITED CULTURES OF MERISMOPEDIA TENUISSIMA (CYANOPHYCEAE)1
Authors: Konopka Allan , Schnur Marilyn
Published: August 2007

Continuous cultures of Merismopedia tenuissima Lemmerman, limited by phosphorus, nitrogen, sulfur, or carbon, were compared to non limited batch cultures by two methods. The cellular content of photosynthetic pigments (chlorophyll and phycocyanin) was found to decrease in all nutrient limited cultures, except for the carbon limited culture. The ratio of carbohydrate to protein was 4‐ to 7‐fold higher in P, N or S limited cultures than in non‐limited or C limited cultures. The macromolecular products of photosynthesis were determined in samples to which NaH14CO3 was added. Relative incorporation into protein decreased in P or N limited cultures, increased accumulation of low molecular weight compounds was found in S and P limited cultures, and little change was noted in C limited cultures as compared to non‐limited cultures. Although relative incorporation into protein was significantly greater at 20μEin·m−2·s−1 light intensity than at 180 μEin·m−2.s−1 in non‐limited cultures, this effect was abolished in all nutrient limited cultures. These results suggest that measurement of the cellular carbohydrate to protein ratio and the products of photosynthesis would be useful in the analysis of algal population dynamics in nature.
TRANSPORT OF INORGANIC CARBON AND THE ‘CO2 CONCENTRATING MECHANISM’ IN CHLORELLA EMERSONII (CHLOROPHYCEAE)1
Authors: Beardall John , Raven John A.
Published: August 2007

Chlorella emersonii Shihira et Krauss var. emersonii exhibits ‘C4‐like’ gas exchange characteristics when grown at air levels of CO2, but is ‘C3‐like’ when grown with extra CO2. The total inorganic carbon concentration, and the free CO2 concentration, averaged over the cell interior are higher in air‐adapted cells than can be accounted for by passive CO2 equilibration from the medium and the mean intracellular pH value. The ‘extra’ inorganic C in the air‐grown cells probably cannot all be accounted for in terms of binding to proteins and requires an active transport process to account for it. The electrical potential of the cell interior becomes more negative when the ‘CO2 concentrating mechanism’ is operative; this is most readily explained if the active step in inorganic C accumulation is primary active uniport of HCO3−. Since the ‘CO2 concentrating mechanism’ can operate when CO2 is the species crossing the outer permeation barrier, it is suggested that the site of active HCO3− transport in Chlorella (and other eukaryotes) is the chloroplast envelope, and the plasmalemma in cyanobacteria. This scheme explains the obligatory role of the de‐repressed carbonic anhydrase in C4‐like photosynthesis in algae, but some other data support an explanation of C4‐like photosynthesis in terms of special properties of carbonic anhydrase as a carbon donor to RuBP carboxylase‐oxygenase.
THE FLAGELLAR APPARATUS OF CHILOMONAS PARAMECIUM (CRYPTOPHYCEAE) AND ITS COMPARISON WITH CERTAIN ZOOFLAGELLATES1
Authors: Roberts Keith R. , Stewart Kenneth D. , Mattox Karl R.
Published: August 2007

The major components of the internal flagellar apparatus of Chilomonas paramecium Ehr. are two large microtubular roots and a striated root paralleled by three microtubules. The two microtubular roots overlap at the basal bodies. One microtubular root follows a curved path in the anterior of the cell, and the other extends straight to the posterior passing through a groove in the nucleus. The striated root extends laterally from the basal bodies. Except that it is smaller, the posteriorly directed root bears a strong resemblance to the axostyle of oxymonads. The overall arrangement and structure of the flagellar roots is similar to the pelta, axostyle and costa of trichomonads and the pelta and axostyle of oxymonads, groups of mitochondrion‐less, largely parasitic or symbiotic protozoans. An affinity between cryptomonads and oxymonads or trichomonads would have many phylogenetic implications, some of which are discussed.
ULTRASTRUCTURAL STUDIES ON SPHAEROPLEA ANNULINA (CHLOROPHYCEAE). II. SPERMATOGENESIS AND MALE GAMETE STRUCTURE1,2
Authors: Cáceres Eduardo J. , Robinson David G.
Published: August 2007

The development and ultrastructure of the male gamete of Sphaeroplea annulina (Roth) Agardh have been investigated. Multiple mitoses each associated with phycoplast microtubules occur as a result of nitrogen deficiency in the culture medium. A regular cleavage of the cytoplasm delineated by microtubules then occurs, resulting in many young male gametes. During maturation the gametes are retained within a vacuolar envelope. Maturation entails reduction in nuclear size and chromatin condensation, loss of chloroplast thylakoids, endoplasmic reticulum and Golgi apparatus. The apical region where the two flagella are inserted consists of an apical cone and fibrous connections which lie distal to the basal bodies. The study supports the suggestion put forward in a previous paper: namely that the genus Sphaeroplea be retained in a separate order the Sphaeropleales.
LIGHT AND ELECTRON MICROSCOPIC STUDIES OF THE FUSION CELL IN ASTEROCOLAX GARDNERI SETCH. (RHODOPHYTA, CERAMIALES)12
Authors: Kugrens Paul , Arif Ibrahim
Published: August 2007

The fusion cell in Asterocolax gardneri Setch, is a large, multinucleate, irregularly‐shaped cell resulting from cytoplasmic fusions of haploid and diploid cells. Subsequent enlargement takes place by incorporating adjacent gonimoblast cells. The resultant cell consists of two parts—a central portion of isolated cytoplasm, surrounded by an electron dense cytoplasmic barrier, and the main component of the fusion cell cytoplasm surrounding the isolated cytoplasm. The fusion cell contains many nuclei, large quantities of floridean starch, endoplasmic reticulum, and vesicles, but few mitochondria, plastids and dictyosomes. The endoplasmic reticulum forms vesicles that apparently secrete large quantities of extracellular mucilage which surrounds the entire carposporophyte. The isolated cytoplasm also is multinucleate but lacks starch and a plasma membrane. Few plastids, ribosomes and mitochondria are found in this cytoplasm. However, numerous endoplasmic reticulum cisternae occur near the cytoplasmic barrier and they appear to secrete material for the barrier. In mature carposporophytes, all organelles in the isolated cytoplasm have degenerated.
EFFECTS OF COPPER TOXICITY ON SILICIC ACID UPTAKE AND GROWTH IN THALASSIOSIRA PSEUDONANA11
Authors: Rueter John G. , Chisholm Sallie W. , Morel Francois M. M.
Published: August 2007

The toxicity of Cu to Thalassiosira pseudonana (Hustedt) Hasle and Heimdal was investigated by examining both short and long term effects of Cu on cellular processes. Toxic levels of Cu (pCu* < 13) were found to inhibit short term Si(OH)4 uptake rates with kinetics characteristic of irreversible inhibition at a hypothetical Cu‐sensitive Si(OH)4 transport site. Residual Si(OH)4 concentrations (those below which no uptake could occur) were found to increase with increasing levels of Cu, and the toxic effects of Cu could be reversed by increasing the concentrations of Si(OH)4 in the medium. The actual uptake of Cu by the cells was found to vary inversely with the ambient Si(OH)4 concentration. Copper did not inhibit the uptake of NO3− or PO43‐.

The long term inhibition of growth rate by Cu in this species was shown not to be a result of Si deficiency caused by the inhibition of Si(OH)4 uptake. Cu inhibited cells were found to have higher Si cell quotas (including a sizable soluble pool) than the control cultures. They were, however, observed to have aberrant frustules, significantly larger than the control cells, suggesting interference with the silification process as a possible mechanism for inhibition of growth by Cu.

A conceptual model is proposed for the Cu‐Si(OH)4‐growth relationship. It includes a Cu sensitive Si(OH)4 transport site that may also serve to transport Cu into the cell, and growth inhibition mediated by intracellular Cu concentrations which may block cell division or cause general cellular disfunction.
NEW RECORD OF THE MARINE RED ALGA CUBICULOSPORUM (GIGARTINALES) FROM THE SOUTHERN GREAT BARRIER REEF1
Authors: Kraft Gerald T. , Huisman John M.
Published: August 2007

Cubiculosporum koronicarpis Kraft (Cubiculosporaceae, Gigartinales), known previously only from the type locality (southeastern Luzon, Philippines), has been collected at North West Island on the southern Great Barrier Reef. The habitat, distribution and taxonomic status of the species are discussed, and habit features of the new specimens are illustrated.
CULTURE STUDIES ON REPRODUCTION OF SPERMATOCHNUS PARADOXUS (PHAEOPHYCEAE, CHORDARIALES)1
Authors: Müller Dieter G.
Published: August 2007

The life history of Spermatochnus paradoxus (Roth) Kütz. isolated from the Mediterranean Sea was studied in culture. Meiospores develop to a microscopic stage (microthallus) which at 20°C perpetuates asexually by plurilocular sporangia and formation of new microthalli. At 9°C microthalli act as homothallic gametophytes. Fusion of isogametes results in a diploid microthallus which, after differentiation of an apical cell, leads back to Spermatochnus plants. In addition, gametes develop without fusion to form haploid macrothalli, the further fate of which has not been determined. Chromosome numbers alternate between n = 20 ± 2 in the microthalli and 2n = 41 ± 4 in macrothalli.
THE FLAGELLAR APPARATUS OF THE ZOOSPORE OF UROSPORA PENICILLIFORMIS(CHLOROPHYTA)1
Authors: Sluiman Hans J. , Roberts Keith R. , Stewart Kenneth D. , Mattox Karl R. , Lokhorst Gijsbert M.
Published: August 2007

The flagellar apparatus of Urospora penicilliformis (Roth) Aresch. is unique, or at least very unusual among green algae. The flagellar axonemes are rigid, and contain wing‐like projections. There are no central microtubules in the most proximal part of the axoneme. The transition region contains a series of electron dense transverse lamellae rather than a single septum, and lacks a stellate pattern. There is no cartwheel pattern in the proximal part of the basal bodies. The latter are associated with four different types of fibrous elements: ascending striated fibers that attach to an electron dense plate in the papillar center, lateral striated fibers that parallel microtubular roots, fibrous elements that link adjacent basal bodies, and finally two massive striated fibers that descend into the cell, passing closely along the nucleus (system II fibers, or rhizoplasts). Each of the four microtubular flagellar roots is sandwiched between two system I striated structures. The roots are probably equal; they contain proximally four, and distally up to eight microtubules. Based on the zoospore flagellar apparatus, it is concluded that the multinucleate U. penicilliformis is related to the Ulvaphyceae. Finally, a possible explanation in functional terms is given for the peculiar external morphology and behavior of the zoospore.
AMPHIDINIUM CRYOPHILUM SP. NOV. (DINOPHYCEAE) A NEW FRESHWATER DINOFLAGELLATE. II. ULTRASTRUCTURE1
Authors: Wilcox Lee W. , Wedemayer Gary J. , Graham Linda E.
Published: August 2007

The dinoflagellate Amphidinium cryophilum sp. nov. is one of the few gymnodinians to be studied at the ultrastructural level. It resembles other dinoflagellates in the structure of the nucleus, trichocysts, storage materials, flagella, mitochondria, and microbodies. Other features of A. cryophilum less commonly observed in related organisms include a network of small interconnected vesicles, a system of large, peripheral vacuoles, chloroplasts bound by two rather than three membranes, an accumulation body, thylakoid‐associated plastoglobuli, a vesiculated nuclear envelope, a complex tubular pusule, striated flagellar collars, collared pits, and a peduncle. The occurrence of a peduncle, a structure implicated in phagotrophy, in this autotrophic organism is noteworthy. The ultrastructure of the peduncle of A. cryophilum differs significantly from that reported in another dinoflagellate.
THE ATLANTIC SPECIES OF SOLIERIA (GIGARTINALES, RHODOPHYTA): THEIR MORPHOLOGY, DISTRIBUTION AND AFFINITIES1
Authors: Gabrielson Paul W. , Hommersand Max H.
Published: August 2007

Solieria chordalis (C. Agardh) J. Agardh and S. tenera (J. Agardh) Wynne et Taylor exhibit multiaxial growth from a cluster of four to eight obconical apical cells. A single periaxial cell is cut off from each axial cell and successive periaxial cells are rotated 120° in a zig‐zag pattern along each axial filament. Periaxial cells produce branched, laterally diverging filaments which form the cortex. The medulla is composed of axial cells, elongate cells of lateral filaments, stretched interconnecting cells, and secondary rhizoids. The two species are nonprocarpic. Carpogonial branches are 3‐celled, inwardly directed, with a reflexed trichogyne. The auxiliary cell together with associated darkly‐staining inner cortical cells form an association, the auxiliary cell complex, that is recognizable prior to diploidization. A single, unbranched, non‐septate connecting filament issues from the fertilized carpogonium and fuses with the inner, lateral side of an auxiliary cell. Production of an involucre from surrounding vegetative cells is stimulated and a gonimoblast initial is cut off toward the interior of the thallus which divides to form a compact cluster of gonimoblast cells. A fusion cell is produced through fusion of inner gonimoblast cells with the auxiliary cell that, in turn, fuses progressively with cells of the lateral file bearing the auxiliary cell. Mature cystocarps have terminal carposporangia cut off from gonimoblast cells at the periphery of the fusion cell and are surrounded by an involucre with a distinct ostiole. Tetrasporangia are cut off laterally from surface cortical cells which then cut off one or two additional derivatives toward the outside.

A lectotype is designated for Solieria chordalis, but the lectotypification of S. tenera is questioned. We conclude that Solieria is closely related to Rhabdonia and place the Rhabdoniaceae in synonomy with the Solieriaceae.
THE MORPHOLOGY OF AGARDHIELLA SUBULATA REPRESENTING THE AGARDHIELLEAE, A NEW TRIBE IN THE SOLIERIACEAE (GIGARTINALES, RHODOPHYTA)1
Authors: Gabrielson Paul W. , Hommersand Max H.
Published: August 2007

Agardhiella subulata (C. Agardh) Kraft et Wynne is a commonly collected erect, terete, alternately branched, fleshy red alga that is found both intertidally and subtidally in the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico. A single periaxial cell is cut off from each succeeding axial cell in an orthostichous file. The supporting cells of carpogonial branches are homologous with auxiliary cells, being transformed from identical inner cortical cells. The auxiliary cell together with the three to four enlarged, darkly‐staining cortical cells pit‐connected to it form the auxiliary cell complex. Following fusion of a connecting filament to an auxiliary cell the diploid nucleus divides with one nucleus remaining near the point of fusion and the other migrating to the beaked portion of the auxiliary cell. Surrounding vegetative cells divide, forming files of cells that grow toward the auxiliary cell to form the involucre. Cells of the gonimoblast fuse with nearby cortical cells producing a placenta of vegetative and gonimoblast tissue. As the cystocarp matures the inner placental cells become vacuolate while at the periphery terminal and short, unbranched files of gonimoblast cells mature into carposporangia. Tetrasporangia are cut off laterally from surface cells and undergo basal elongation followed by lateral expansion before dividing zonately. A. subulata exhibits a combination of distinctive vegetative and reproductive features when compared with Solieria and thus serves as the type of a new tribe, the Agardhielleae, in the family Solieriaceae.
SIZE DEPENDENCE OF GROWTH RATE, RESPIRATORY ELECTRON TRANSPORT SYSTEM ACTIVITY, AND CHEMICAL COMPOSITION IN MARINE DIATOMS IN THE LABORATORY1
Authors: Blasco Dolors , Packard T. T. , Garfield Paula C.
Published: August 2007

The dependence of growth, electron transport system activity and chemical composition on the size of diatoms was examined during the exponential phase of growth. The six different marine centric species compared ranged in volume from 7.7 μm3 to 62 × 105μm3. A size dependence was observed for growth, 14C uptake, respiration and the productivity index (14C/chl a). Although the size dependence of all parameters was similar, the results indicate that on a carbon basis, growth efficiency decreases with increasing size. The C/N and C/chl a ratios were not size dependent. The importance of the surface area to cell volume ratio, and the importance of carbon per unit volume in determining the observed size dependence are discussed.
REMOVAL OF ORGANIC AND INORGANIC MATTER FROM ANTARCTIC LAKES BY AERIAL ESCAPE OF BLUEGREEN ALGAL MATS1
Authors: Parker Bruce C. , Simmons George M. , Wharton Robert A. , Seaburg Kenneth G. , Love F. Gordon
Published: August 2007

Field studies on three perennially ice‐covered Antarctic oasis lakes with little or no outflow disclosed a unique biological phenomenon. Benthic algal mats dominated by the prokaryotic Phormidium frigidum Fritsch and several pennate diatoms growing in shallower, more brightly illuminated areas beneath 4 to 5.5 m of ice accumulate and entrap bubbles of photosynthetically produced oxygen. Clumps of this gas‐filled mat tear loose from the gravelly substrate, lift off and float to the bottom of the lake ice. Some of these floating mat pieces become frozen into newly forming ice with the onset of winter. Through the combination of ablation of ice from the upper surface and the formation of new ice from below, algal mat pieces reach the upper lake surface in 5–10 years. Here, they are lyophilized by polar winds and dispersed in at least a partially viable state. The process of mat lift‐off and escape is important in removing nutrients and salts from these lakes and helps to perpetuate their oligotrophic state. Neutron activation and X‐ray dispersive analyses of elements in the algal mats along with other analyses, field observations, and calculations suggest that significant quantities of organic matter, select minerals and salts are lost from the lakes annually through this process whose magnitude has not been recognized previously.
HALIMEDA HUMMII SP. NOV., HALIMEDA CRYPTICA V. ACERIFOLIA VAR. NOV. (CAULERPALES, CHLOROPHYTA), AND ADDITIONAL RECORDS OF HALIMEDA SPECIES FROM: PUERTO RICO1
Authors: Ballantine David L.
Published: August 2007

A new species, Halimeda hummii, and a new variety of Halimeda cryptica Colinvaux and Graham both originally collected from the edge of the continental shelf on the southwest coast of Puerto Rico are newly described. The new species is irregular in its segment morphology and is the smallest species of Halimeda presently known. Halimeda cryptica var. acerifolia from deep water possesses distinctive segments resembling maple leaves. Halimeda copiosa Goreau and Graham and typical H. cryptica are also collected in deep water and are newly recorded from Puerto Rico.
EFFECTS OF LIGHT AND TEMPERATURE ON NET PHOTOSYNTHESIS AND DARK RESPIRATION OF GAMETOPHYTES AND EMBRYONIC SPOROPHYTES OF MACROCYSTIS PYRIFERA1
Authors: Fain Steven R. , Murray Steven N.
Published: August 2007

The rates of net photosynthesis as a function of irradiance and temperature were determined for gametophytes and embryonic sporophytes of the kelp, Macrocystis pyrifera (L.) C. Ag. Gametophytes exhibited higher net photosynthetic rates based on oxygen and pH measurements than their derived embryonic sporophytes, but reached light saturation at comparable irradiance levels. The net photosynthesis of gametophytes reached a maximum of 66.4 mg O2 g dry wt−1 h−1 (86.5 mg CO2 g dry wt−1 h−1), a value approximately seven times the rate reported previously for the adult sporophyte blades. Gametophytes were light saturated at 70 μE m−2 s−1 and exhibited a significant decline in photosynthetic performance at irradiances 140 μE m−1 s−1. Embryonic sporophytes revealed a maximum photosynthetic capacity of 20.6 mg O2 g dry wt−1 h−1 (25.3 mg CO2 g dry wt−1 h−1), a rate about twice that reported for adult sporophyte blades. Embryonic sporophytes also became light saturated at 70 μE m−2 s−1, but unlike their parental gametophytes, failed to exhibit lesser photosynthetic rates at the highest irradiance levels studied; light compensation occurred at 2.8 μE m−2 s−1. Light‐saturated net photosynthetic rates of gametophytes and embryonic sporophytes varied significantly with temperature. Gametophytes exhibited maximal photosynthesis at 15° to 20° C, whereas embryonic sporophytes maintained comparable rates between 10° and 20° C. Both gametophytes and embryonic sporophytes declined in photosynthetic capacity at 30° C. Dark respiration of gametophytes was uniform from 10° to 25° C, but increased six‐fold at 30° C; the rates for embryonic sporophytes were comparable over the entire range of temperatures examined. The broader light and temperature tolerances of the embryonic sporophytes suggest that this stage in the life history of M. pyrifera is well suited for the subtidal benthic environment and for the conditions in the upper levels of the water column.
PEROXIDASE IN CAULERPA1
Authors: Menzel D. , Grant B. R.
Published: August 2007

A survey of 17 species of Caulerpa showed peroxidase activity to be widespread in this genus. The intracellular location of the activity varied in different species, but only in C. cliftoni Harvey was it associated with wound plugs. In eight species peroxidase activity was present in the branching points of the trabeculae and in 12 of the 17 species it was found in the cell wall or in the trabeculae adjacent to the cell wall. Peroxidase was isolated from one species, C. simpliciuscula C. Ag., and some of its properties examined. Two isoenzymes were present, both of them different from the peroxidase isolated from Batophora oerstedii J. Agardh and Cymopolia barbata L.