bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunocompetence of bivalve hemocytes as evaluated by a miniaturized phagocytosis assay
Authors: Blaise C. , Trottier S. , Gagné F. , Lallement C. , Hansen P.‐D.
Published: October 2002

Immune function in bivalves can be adversely affected by long‐term exposure to environmental contaminants. Investigating alterations in immunity can therefore yield relevant information about the relationship between exposure to environmental contaminants and susceptibility to infectious diseases. We have developed a rapid, cost‐effective, and miniaturized immunocompetence assay to evaluate the phagocytic activity, viability, and concentration of hemocytes in freshwater and marine bivalves. Preliminary experiments were performed to optimize various aspects of the assay including 1) the time required for adherence of hemocytes to polystyrene microplate wells, 2) the time required for internalization of fluorescent bacteria, 3) the ratio of hemocytes to fluorescent bacteria in relation to phagocytosis, 4) hemolymph plasma requirements, and 5) the elimination of fluorescence from (noninternalized) bacteria adhering to the external surface of hemocytes. The results of these experiments showed the optimal adherence time for hemocytes in microplate wells to be 1 h, that phagocytosis required at least 2 h of contact with fluorescently labeled E. coli cells, that the number of fluorescent E. coli cells had a positive effect on phagocytic activity, that at least 2.5 million cells/mL were required to measure a significant intake, and that a linear increase in uptake of bacteria (R = 0.91; p < 0.01) could be obtained with concentrations of up to 1.3 × 106 hemocytes/mL. Afterward, the assay was used in two field studies to identify sites having the potential to affect the immunocompetence of bivalves. The first study was conducted on Mya arenaria clams collected at selected contaminated sites in the Saguenay River (Quebec, Canada), and the second examined Elliptio complanata freshwater bivalves that had been exposed to a municipal effluent plume in the St. Lawrence River (Quebec, Canada). In the Saguenay River field study a significant increase in phagocytosis was observed at sites closest to polluted areas. Phagocytotic activity varied over time and was highest during the warmest months (June, July, and August), closely paralleling the spawning period of Mya arenaria clams. In contrast, a drop in phagocytic activity was observed in Elliptio complanata mussels exposed to surface water 4 km downstream of a major municipal effluent plume, with a concomitant increase in the number of hemocytes in the hemolymph. It appears that both immunosuppressive and immunostimulative effects are likely to occur in the field and that responses will be influenced by the type and intensity of contaminants at play. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 160–169, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10047
A novel nucleolar biomarker in plant and animal cells for assessment of substance cytotoxicity
Authors: Arkhipchuk V. V. , Garanko N. N.
Published: October 2002

The cytotoxicity of three substances (mercuryII, metolachlor, and 4‐nitroquinoline‐N‐oxide) was assessed with a set of nucleolar parameters: the average number of nucleoli, the average volume of a single nucleolus, and the proportion of cells with heteromorphic‐paired nucleoli (PNhet). Their toxic impact was studied on cells of animal and plant test organisms: onion (Allium cepa), lettuce (Lactuca sativa), and hydra (Hydra attenuata). In general, at concentrations near IC/LC50 the three chemicals produced similar cytogenetic effects after 30–360 min of contact. For instance, in plant cells (Allium cepa and Lactuca sativa) the toxicants increased the percentage of cells with PNhet, decreased the volume of single nucleoli, and exerted no significant impact on the nucleolar number. In animal cells (Hydra attenuata), they reduced the size of nucleoli, produced no effect on the number of nucleoli, but decreased the share of cells with PNhet. Also, the chemicals affected the cells of the three test organisms to different degrees. Thus, the effectiveness of our approach of using nucleolar biomarker (use of the proposed set of parameters and time schedule of several determinations in the first hours of toxicant contact, etc.) as a means of assessing cytotoxicity was confirmed. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 187–194, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10056
Multi‐carrier platform for wireless communications. Part 2: OFDM and MC‐CDMA systems with high‐performance, high‐throughput via innovations in spreading
Authors: Nassar Carl R. , Natarajan Bala , Wiegandt David , Wu Zhiqiang
Published: October 2002

Multi‐carrier technologies in general, and OFDM and MC‐CDMA in particular, are an integral part of the wireless landscape. In this second part of a two‐part survey, the authors present an innovative set of spreading codes known as CI codes, and demonstrate how these significantly increase performance and capacity in OFDM and MC‐CDMA systems, all the while eliminating PAPR concerns. Regarding OFDM: the spreading of each symbol over all N carriers using CI spreading codes (replacing the current one symbol per carrier strategy) are presented. CI codes are ideally suited for spreading OFDM since, when compared to traditional OFDM, CI‐based OFDM systems achieve the performance of coded OFDM (COFDM) while maintaining the throughput of uncoded OFDM, and, at the same time, eliminate PAPR concerns. When applied to MC‐CDMA, CI codes provide a simple means of supporting 2N users on N carriers while maintaining the performance of an N‐user Hadamard Walsh code MC‐CDMA system, i.e., CI codes double MC‐CDMA network capacity without loss in performance. The CI codes used in OFDM and MC‐CDMA systems are directly related to the CI pulse (chip) shapes used to enhance TDMA and DS‐CDMA (see part 1): hence, the CI approach provides a common hardware platform for today's multi‐carrier/multiple‐access technologies, enabling software radio applications. Copyright © 2002 John Wiley & Sons, Ltd.
Measurement of L subshell x‐ray production cross‐sections at energy 31.635 keV and L subshell fluorescence yields for elements 74 ≤ Z ≤ 92
Authors: Ertuǧrul M. , Kaya A. , Doǧan O. , Turgut Ü. , Şimşek Ö. , Söǧüt Ö. , Karagöz D.
Published: October 2002

The Ll, Lα, Lβ and Lγ x‐ray production cross‐sections were measured for seven elements in the atomic range 74 ≤ Z ≤ 92 at 31.635 keV. The values of Li subshell fluorescence yields (ω1, ω2 and ω3) were measured for the same elements using these measured cross‐section values and the theoretical Li subshell photoionization cross‐sections, Coster–Kronig transition probabilities and emission rates. The measured x‐ray production cross‐sections values are in general agreement with the theoretical values evaluated using L subshell fluorescence yields, Coster–Kronig transition probabilities, emission rates and subshell photoionization cross‐sections. Copyright © 2002 John Wiley & Sons, Ltd.
Management and husbandry of duikers at the Los Angeles Zoo
Authors: Barnes Robert , Greene Kelley , Holland Jeff , Lamm Marnie
Published: October 2002

The Los Angeles Zoo has maintained and managed six different species of forest duikers since 1975. Over the years we have achieved relative success with the majority of these species. The maintenance and breeding of duikers has proved to be difficult at best. The major problems that we have experienced concern diet, stress‐related medical conditions, neonatal mortality, and postanesthetic pneumonia. As concentrate selectors, duikers have a diet relatively low in fiber, a well‐developed ability to forage selectively, a rumen bypass that is functionally important, a rapid passage and high fermentation rate for starch, and frequently encountered toxins. From an examination of the captive diet of duikers it is evident that the domestic fruits fed to duikers in captivity are not well suited for them. Duikers are highly susceptible to the slightest amount of stress. The group size in which duikers are managed has proved to be critical in the successful management of these species. In our earlier years of duiker management we often kept five or more animals together in a single exhibit. This would at times result in stress‐related jaw abscesses. Our group size has since been reduced to no more than three animals in any one exhibit. Since 1977, the Los Angeles Zoo has had 92 duiker births. The survival rate past 6 months of age has been 61%. Of the 36 neonatal deaths, 42% were stillborn or died within a few hours of birth. Hypothermia and maternal neglect have been linked to infant mortality. Duikers are also easily prone to capture myopathy and regurgitation during anesthesia or capture, which can often lead to aspiration pneumonia. If at all possible, the capture and restraint of a duiker should be avoided. However, there are times when the capture or restraint (chemically or manually) of a duiker is required. Zoo Biol 21:107–121, 2002. © 2002 Wiley‐Liss, Inc.
Cytochemical analysis of the content of chicken thrombocytes vacuoles.
Authors: Taffarel Marilia , Oliveira Marcia P.
Published: October 2002

The content of the large vacuoles present in chicken thrombocytes was analyzed by the use of cytochemical techniques which indicated the presence of basic proteins, unsaturated fatty acids, sugars rich in viccinal hydroxyl groups, linked to proteins or lipids and acid phosphatase. These substances perform one of the most conspicuous functions of these cells, which is phagocytosis. In addition, thrombocytes are committed to hemostasis. Both functions make these cells similar to human platelets, even though having different origins and morphologic characteristics. The large vacuoles described are connected to the open canalicular system (OCS) and together with other cellular structures they contribute to the endocytic system.
The development of an enzyme‐linked immunosorbent assay for the determination of cortisol binding globulin.
Authors: van Rijswijk A. W. , Morgenthal J. C. , Taljaard J. J. F.
Published: October 2002

A simple, reliable and reproducible enzyme‐linked immunosorbent assay (ELISA) using polyclonal antibodies for human cortisol binding globulin (CBG) has been developed. The sensitivity of the ELISA (1.20 fmol CBG/well) compared favourably with the sensitivity of other immunoassays. The excellent agreement (r= 0.98) seen between the present study and a binding assay indicates that the polyclonal antibodies used recognize only intact steroid‐binding CBG. The intra‐ and inter‐assay coefficient of variation (4.0% and 7.1% respectively) compared favourably with those reported by other authors.
Spatio‐temporal regulation of glycolysis and oxidative phosphorylation in vivo in tumor and yeast cells.
Authors: Cortassa Sonia , Aon Miguel A.
Published: October 2002

Recent advances in the in vivo control and regulation of glycolysis and oxidative phosphorylation in yeast and tumor cells is revised. New insigths are presented from old and new experimental data interpreted in the light of powerful new technologies (e.g. NMR confocal microscopy) and quantitative techniques combined with mathematical modeling. Those new aspects are mainly concerned with the dynamical organization of glycolysis and oxidative phosphorylation which emerges from the multiple interactions between compartments and processes inside the cells. Those compartments may be of structural origin, e.g. plasma membrane defining the cell boundary, mitochondrial‐cytoplasmic, or functional ones such as the alternative association‐dissociation of enzymes to subcellular structures (e.g. mitochondria, cytoskeleton) with different kinetic properties in each state. A novel regulatory mechanism concerning polymerization‐depolymerization of microtubular protein may add a new dimension to the in vivo physiological properties of cells. One main suggestion coming from the modulatory power of the polymeric status and concentration of cytoskeleton components is that it could function as an intracellular mechanism of synchronization between microscopic (local) to macroscopic (global) processes. How the cell "mixes" or switches on or off those regulatory steps or effectors under different physiological and environmental conditions and for different genetic backgrounds, is a main avenue of systematic research for the future.
Nucleolar organization as revealed in cycloheximide treated cells
Authors: Ghosh Sibdas , Paweletz Neidhard
Published: October 2002

The nucleolar organisation has been studied in cycloheximide treated rat kangaroo cells. Within 1 h of treatment most nucleoli become loose and reveal a nucleolonemal network. With longer treatment the granules are scarce and the nucleolonemal network becomes more prominent. The network reveals units comparable to the rDNA transcriptional units in length. The nucleolonemal units consist of tufts of fibrils. When cycloheximide is withdrawn, granules reappear and obliterate the nucleolonemal network.
Metabolism of N′‐nitrosonornicotine by adult and fetal human oesophagal cultures
Authors: Chakradeo P. P. , Nair J. , Bhide S. V.
Published: October 2002

The metabolism of [3H]labelled N‐Nitrosonornicotine a major constituent of the class of Tobacco Specific Nitrosamines was studied in adult and fetal human oesophageal cultures. The metabolites were separated by HPLC and were identified when compared to the standards as OH‐acid from 5′hydroxylation, NNN‐1‐N‐oxide formed via the pyridine N‐oxidation pathway and Keto acid from 2′hydroxylation in both the adult and fetal cultures. These results indicate that hydroxylation which leads to electrophilic diazohyroxides is the major pathway of NNN metabolism in cultured human oesophagus. In the adult cultures levels of metabolites formed were 20.32 pmoles/μg DNA of OH acid 11.08pmoles/μg DNA of NNN‐1‐N‐oxide and 7.67pmoles/μg DNA of Keto acid. In the fetal cultures levels were 10.85pmoles/μg DNA of OH acid, 9.40pmoles/μg DNA of NNN‐1‐N‐oxide and 7.91pmoles/μg DNA of Keto acid. These results indicate that α‐hydroxylation is the key step in the metabolic activation of NNN in human oesophagus.
A GCN‐like response in Candida albicans.
Authors: Pereira Sarita Anne , Livi George P.
Published: October 2002

The control of amino acid and purine biosynthesis in the yeast Saccharomyces cerevisiae is mediated by the transcriptional activator GCN4. We previously identified the presence of two putative GCN4 responsive elements (GCREs) in the promoter sequence of the Candida albicans ARO3 gene, which encodes an enzyme in the aromatic amino acid pathway. We now show that amino acid deprivation results in a dramatic rise in the steady‐state level of ARO3‐specific mRNA, indicative of a GCN‐like pathway in C. albicans.
Tyrphostin induces non‐apoptotic programmed cell death in colon tumor cells
Authors: Szende B. , Kéri Gy. , Szegedi Zs. , Benedeczky I. , Csikós A. , Örfi L. , Gazit A.
Published: October 2002

The programmed cell death inducing effect of the EGF receptor tyrosine kinase inhibitor α‐cyano‐3,4‐dihydroxycinnamthioamide (AG213) was investigated in vitro on HT‐29 human colon tumor. AG213 at concentrations between 45 to 450 μM blocks the proliferation of HT‐29 cells. Morphological findings suggest that the selective tyrosine kinase inhibitor AG213 induces Clarke III type (non‐lysosomal vesiculate cytoplasmic) programmed cell death; unlike ATP analog non‐selective tyrosine kinase inhibitors like Genistein which were found to induce apoptosis. Cycloheximide and Actinomycin‐D reduced the effect of AG213 pointing to the fact that protein and RNA synthesis are also needed for this form of cell death. Acid phosphatase activity was found in the Golgi and in the newly formed intracytoplasmic vacuoles 3 hours after AG213 treatment which disappeared by 6 hours. The induction of Clarke III cell death by tyrosine kinase inhibitors may open a new modality to selective killing of tumor cells.
The DNA binding affinity of rat liver nucleoproteins to the regulatory elements of the haptoglobin and α2‐macroglobulin genes.
Authors: Petrović Miodrag , Bogojević Desanka , Grigorov Ilijana , Ševaljević Ljiljana
Published: October 2002

Transcriptional regulation and binding interactions between soluble nucleoproteins and the hormone response elements (REs) of the rat haptoglobin (Hp) and α2‐macroglobulin (α2MG) genes was examined in the livers of rats during the acute‐phase reaction. Our results demonstrate that the elevation of the Hp and α2MG genes' transcription rates in acute‐phase liver relies essentially on an increase in the binding‐affinity of pre‐xisting soluble nucleoproteins, enhancing their capability to bind the examined cis‐regulatory elements. The 35kD nucleoprotein that displayed an acute‐phase inducible affinity to bind hormone REs of rat Hp and α2MG genes, was identified as a C/EBPβ isoform.
The histopathological effect of Detarium microcarpum extract, a naturally occurring plant molluscicide on the mid‐gut and digestive gland of Lymnaea stagnalis
Authors: Kela Santaya L. , Bowen Ivor D.
Published: October 2002

The histology, fine structure and histochemistry of the digestive gland of Lymnaea stagnalis was examined before and after treatment with a crude water extract of a powerful molluscicidal plant, Detarium microcarpum. The results obtained indicate that the molluscicidal extract induces necrosis in the digestive gland typified optically by cellular oedaema and nuclear pyknosis. At electron microscope level molluscicide treatment is seen to induce a major vacuolation and fragmentation of the cytoplasm. Lysosomal acid phosphatase and lysosomal integrity however is preserved. Histochemically, both acid and alkaline phosphatase appear to survive treatment very well. In treated tissues there is a shift of alkaline phosphatase from the brush border to the lumen. Molluscicide treatment results in a distinct inhibition of ATPase activity which appears to be a characteristic feature of induced cell death.
Non‐random jumping translocations as a result of SV40 large T‐antigen expression in benign human tumor cells.
Authors: Kazmierczak Bernd , Stern Corinna , Bartnitzke Sabine , Bullerdiek Jorn
Published: October 2002

In an attempt to analyse the cytogenetic effects caused by SV40 large T‐antigen expression in cells of human benign tumors we transfected cells of an uterine leiomyoma characterized by a primary reciprocal translocation t(12;14)(q15;q24) and a pleomorphic adenoma of the salivary gland with an inversion inv(12) (q15q24.1) using a construct coding for SV40 large and small T‐antigen. The most interesting finding was not a generally destabilized karyotype, but the strictly non‐random involvement of two chromosomal breakpoints, i.e. 5p13 and 10q11 in jumping translocations, never described before as a result of SV40 transformation. In addition we were able to show by non‐radioactive in situ hybridization that there was no direct relationship between the integration site of the construct and the pre‐disposition of 5p13 and 10q11 to somatic recombination. The jumping translocations with consistent breakpoints observed closely resemble the cytogenetic situation seen in a variety of human tumors with specific translocations. Based on the findings described here it is tempting to assume that the expression of SV40 large T‐antigen can induce specific karyotypic alterations following an unknown trans‐acting mechanism.
Demonstration of endothelin (ET) receptors on cultured rabbit chondrocytes and stimulation of DNA synthesis and calcium influx by ET‐1 via its receptors
Authors: Kinoshita Akihiro , Tamura Tomoo , Aoki Chiharu , Nakanishi Tohru , Sobue Shizuo , Suzuki Fujio , Takahashi Kojiro , Takigawa Masaharu
Published: October 2002

Endothelin (ET) receptors on chondrocytes were demonstrated using cultured rabbit costal chondrocytes. After crosslinking the receptors on the cells with 125 I‐ET‐1, two major bands of 43 kDa and 46 kDa were separated by SDS‐PAGE. Scatchard analysis demonstrated two classes of ET receptors with Kd values of 1 × 10−10 M and 5 × 10−9 M. The numbers of high‐ and low‐ affinity receptors were 1 × 104 and 2 × 105 per cell, respectively. The binding of ET‐1 to chondrocytes was increased by treatment with PTH, DBcAMP, TGF‐β1, IL‐1β, RA and EGF. ET‐1 stimulated DNA synthesis in cultured rabbit chondrocytes. ET‐1 also stimulated calcium incorporation through the cell membrane of chondrocytes. These findings indicate that ET‐1 has a physiological effect on chondrocytes via its receptors on the cells.
EXPRESSION OF PRIMARY CILIA IN MAMMALIAN CELLS
Authors: WHEATLEY DENYS N. , WANG AI MEI , STRUGNELL GILLIAN E.
Published: October 2002

Mammalian cellsin vivofrequently express primary cilia. Although some fully differentiated cell types rarely, if ever, express them, most do, indicating that they are regular cell organelles. Their expression can also be exploredin vitro, where conditions—physical and chemical, intrinsic and extrinsic—permit experimental approaches which give far greater control thanin vivo. This ‘state of the art’ paper covers briefly the general biology of primary cilia, highlights the current situation with regard to our understanding of their relevance and importance in cell biology from various facets of our recent research, much of it in collaboration with other laboratories world‐wide, and outline future work aimed at answering some basic and applied questions about them, within a context of an increasing awareness that signalling between cells is of the utmost importance in understanding proliferation control and its value in cancer research, the major remit of this unit.
CONNEXIN EXPRESSION AND GAP JUNCTIONS IN THE MAMMARY GLAND
Authors: MONAGHAN PAUL , MOSS DAVID
Published: October 2002

Gap junctional communication plays a vital role in embryogenesis, cell differentiation and the co‐ordination of tissue responses. Gap junctions are formed by a family of closely‐related proteins called connexins which show tissue‐specific patterns of expression. The role of gap junctions in the mammary gland remains unclear. The lumena of mammary gland ducts are lined by luminal cells with an outer layer of basal cells. In rodents, the luminal cells express connexin26 only during pregnancy and lactation and the basal cells, in some reports, express connexin43. In the normal human breast the basal cells express connexin43, although human mammary epithelial cellsin vitrohave been reported to express both connexin26 and connexin43. Analysis of connexin expression at the molecular level is now bringing new insights into the structure and function of gap junctions in a range of normal and pathological cell systems.
HIGH AND LOW DENSITY WATER AND RESTING, ACTIVE AND TRANSFORMED CELLS
Authors: WIGGINS PHILIPPA M.
Published: October 2002

Resting and active states of cells are described in terms of the expectation, derived from experiments with aqueous polymers, that they contain two modified forms of water: high density, reactive, fluid water and low density, inert, viscous water. Low density water predominates in a resting cell and is converted to high density water in an active cell. It is proposed that switching from one state to another is an integral part of cellular function. When this ability is lost cells are transformed either to a state of rigor or to a hyperactive state in which they no longer depend upon external signals.
INDEPENDENT HIGH‐FREQUENCY OSCILLATIONS IN THE AMOUNTS OF INDIVIDUAL ISOZYMES OF LACTATE DEHYDROGENASE IN HL60 CELLS
Authors: FERREIRA G. M. N. , HAMMOND K. D. , GILBERT D. A.
Published: October 2002

Early studies, using kinetic methods, suggested that the isozyme pattern of lactate dehydrogenase in various cells oscillated with time. More recent electrophoretic studies on murine erythroleukaemic cells (which exhibit only one isozyme) indicated very high frequency variations (period 2min or less) in the amount of the lone active isozyme. We now show that in HL60 cells, the activity stain intensities of the two major isozyme bands both oscillate but the temporal variations are distinct. As with other cellular rhythms, each of the two periodicities seem to be modulated in cyclic fashion with respect to period, amplitude and mean levels, the periods of both the primary and modulating rhythms being of the order of 10–15min or probably much less.
ENHANCEMENT OF FERTILIZATION BY PIPERINE IN HAMSTERS
Authors: PIYACHATURAWAT PAWINEE , PHOLPRAMOOL CHUMPOL
Published: October 2002

The effect of piperine on the fertilization of eggs with sperm was investigated in female hamsters. They were intragastrically treated with piperine at doses of 50 and 100mg/kg BW from day 1 through day 4 of the oestrous cycle. During piperine treatment, these females were superovulated and artificially inseminated (AI) with spermatozoa from untreated male hamsters at 12h after hCG injection. The fertilization and growth of embryos were examined at various times after AI. In control hamsters, the percent fertilization increased with time, from 27.4±3.3% at 9h after AI to 75.3±9.6 at 24h after AI. Administration of piperine to the superovulated animals markedly enhanced the percent fertilization at 9h after AI. It was increased to 85.4±4.1 and 82.8±4.8% by piperine at doses of 50 and 100mg/kg BW, respectively. However, examination of the embryos retrieved 48h after AI revealed no differences in the stage of embryonic development among different groups of animals. The possibility that this effect was due to the direct action of vanillic acid, a major piperine metabolite, was testedin vitroDirect exposure of spermatozoa to vanillic acid at doses 25–100mg% did not significantly affect their motility, percent acrosome reaction or fertilizing ability. This suggests that the enhancement of fertilization by piperine treatment was not related to the secretion of vanillic acid into the oviduct.
USE OF FLUORESCENT DYES FOR MEASUREMENT AND LOCALIZATION OF ORGANELLES ASSOCIATED WITH CA2+ STORE RELEASE IN HUMAN NEUTROPHILS
Authors: DAVIES ERYL V. , BLANCHFIELD HELEN , HALLETT MAURICE B.
Published: October 2002

Fura‐2 and its lipid analogue, FFP‐18, were used to measure changes in cytosolic free Ca2+concentration within human neutrophils. Whereas fura‐2 was employed to monitor cytosolic Ca2+increases throughout the cytosol, FFP‐18 was used to monitor Ca2+changes only near the membrane. This latter probe was incorporated into the plasma membrane as its acetoxymethyl ester (FFP‐18‐AM) but as de‐esterification was catalysed by cytosolic esterases, the Ca2+‐sensing probe (FFP‐18 acid) accumulated on the inner face of membrane. The fluorescence of esterified probe on the extracellularly facing membrane leaflet was quenched by the membrane‐impermeant ion Ni2+. Under these conditions, near membrane Ca2+changes which resulted from the release of Ca2+from intracellular stores was possible by conventional ratio fluorescence measurement of FFP‐18. From the timing of arrival of Ca2+at the plasma membrane, it was proposed that there were two Ca2+storage sites, liberated by different stimuli, one close to the plasma membrane and the other more distant. In order to discover whether organelles within the neutrophil had distributions which correlate with the Ca2+release sites, fluorescent dyes for structures within the cytosol were employed. We have previously shown that the location of the intracellular membrane stain, DiOC6(3) corresponds to the distant Ca2+release site. Here a second stain, BODIPY‐C5ceramide, has also been used and is shown to stain a peripheral region of the neutrophil, in a similar pattern to the near membrane Ca2+storage site. These data therefore raise the question of whether these stains mark the organelles in neutrophils which are the two Ca2+storage and release sites.
AFM IMAGING AND ELASTICITY MEASUREMENTS ON LIVING RAT LIVER MACROPHAGES
Authors: ROTSCH CHRISTIAN , BRAET FILIP , WISSE EDDIE , RADMACHER MANFRED
Published: October 2002

The authors investigated the morphology and the elastic properties of living cultured rat liver macrophages (Kupffer cells) with an atomic force microscope (AFM). Continuous imaging and elasticity mapping of individual cells in physiological buffer was carried out for several hours without damaging the cells as judged by their persistent undisturbed morphology. Dynamic events such as protrusive activity were observed in time course. The importance of the cytoskeleton for the mechanical properties of the cell has been investigated by measuring the cell's elasticity as a function of position. Chemical disassembly of the actin network by applying 10μg/ml cytochalasin B decreased the cell's average elastic modulus seven‐fold within less than 40 minutes. Treating the cells with 0.1μg/ml latrunculin A resulted in a two‐fold decrease in the elastic modulus merely in the perinuclear region after 40 minutes, whereas other parts of the cell were not affected.
BINDING PROPERTIES OF BOVINE OCULAR LENS ZETA‐CRYSTALLIN TO RIGHT‐HANDED B‐DNA, LEFT‐HANDED Z‐DNA, AND SINGLE‐STRANDED DNA
Authors: GAGNA CLAUDE E. , CHEN JOHN H. , KUO HON‐REEN , LAMBERT W. CLARK
Published: October 2002

Bovine zeta‐crystallin has the ability to bind with different DNAs. Initially, this protein was named regulatory factor 36 (Kang et al., 1985), but it has been shown to be an ocular lens zeta‐crystallin (Jörnvall et al., 1993), which is considered an enzyme‐crystallin (Rodakanaki et al., 1989). The enzyme‐linked immunosorbent assay (ELISA) was used to quantitate the binding of bovine zeta‐crystallin to purified high molecular weight double‐stranded (ds‐) and single‐stranded (ss‐) DNA (bovine and synthetic DNA). ELISA quantitation was achieved by the addition of anti‐zeta‐crystallin antibodies to the DNA—zeta‐crystallin complex, using a novel immunochemical avidin—biotin method. Zeta‐crystallin shows much greater binding intensity for ss‐DNA and for ds‐Z‐DNA than for ds‐B‐DNA. It also reacts slightly more with ds‐Z‐DNA than ss‐DNA. Therefore, we speculate that zeta‐crystallin may act as a transcriptional enhancer (outer lens cortex), possibly binding to Z‐DNA regulatory elements within lens crystallin genes. It may also act to protect DNA from endogenous DNase activity and as a DNA unwinding (destabilizing) protein also involved with transcription, occurring in normal adult bovine lens nucleated secondary fiber cells.
EFFECT OF DEXAMETHASONE ON THE ASSEMBLY OF THE MATRIX OF FIBRONECTIN AND ON ITS RECEPTORS ORGANIZATION IN EHLERS‐DANLOS SYNDROME SKIN FIBROBLASTS
Authors: ZOPPI NICOLETTA , GHINELLI ANNALISA , GARDELLA RITA , BARLATI SERGIO , COLOMBI MARINA
Published: October 2002

The effect of dexamethasone (DEX) on the expression of fibronectin (FN), proα1(I) collagen (Col1), integrin α2, α5and β1subunits mRNAs, were studied by quantitative in situ hybridization (ISH) with radiolabelled probes in relationship with the organization of the extracellular matrix (ECM) of FN in human skin fibroblasts. In particular, two fibroblast strains were analysed, one derived from a control donor, typically organizing a rich ECM of FN, and the other from a patient affected by Ehlers‐Danlos syndrome (EDS), which did not assemble the FN‐ECM.

Treatment of both fibroblast strains with 10−7mDEX slightly enhanced the level of FN mRNA (by about 1.5‐fold), did not influence the level of α5subunit mRNA and reduced Col1, α2and β1integrin subunits mRNAs by 2–3‐fold. These results show that, in these cells, DEX coordinately downregulates the expression of Col1 and its specific integrin α2β1. Moreover, DEX regulates in a different manner the α5and β1subunits forming the main FN receptor (FNR) in skin fibroblasts.

Immunofluorescence microscopy evidencing the FN‐ECM and integrins containing α5and β1subunits showed that in control cells DEX induced a slight enhancement of the FN‐ECM and of the α5β1receptors patches. Therefore, in these cells the decrease of β1FN receptor subunit mRNA, as well as the decrease of Col1 and its receptor mRNAs, did not influence the FN‐ECM assembly. In EDS fibroblasts, DEX decreased the cytoplasmic accumulation of FN and induced the assembly of a rich FN‐ECM through the formation of large FNR integrin patches, codistributing with the FN‐ECM. We suggest that in EDS skin fibroblasts DEX corrects the defective FN‐ECM favouring the sorting and the organization of FN and its α5β1integrin receptor.
EXPRESSION OF MAJOR GAP JUNCTION CONNEXIN TYPES IN THE WORKING MYOCARDIUM OF EIGHT CHORDATES
Authors: BECKER DAVID L. , COOK JEREMY E. , DAVIES CATHERINE S. , EVANS W. HOWARD , GOURDIE ROBERT G.
Published: October 2002

The α1 connexin (connexin43) is regarded as the major gap junction protein of the myocardium because it predominates there in mammals. Here, we show that it is not the major connexin of the working myocardium in non‐mammalian vertebrates, which instead express β1‐like connexins homologous to mammalian connexin32. A phylogenetic series of hearts was immunostained with seven antibodies raised against peptide sequences specific for three distinct members of the gap junction connexin family: α1, β1 and α5 (mammalian connexin40/avian connexin42). Working myocardium from two ascidian chordates (Ciona and Mogula), a teleost (Carassius), a frog (Xenopus) and two reptiles (Anolis and Alligator) was found to express a β1‐like connexin, rather than an α1‐like connexin. An α1‐like connexin was nevertheless often detected in other cardiac tissues. In the chicken (by ancestry a reptile), the developing myocardium expressed a β1‐like connexin strongly on embryonic day 6 but less strongly at hatching, and minimally in the adult. Myocardial expression of α5 connexin increased during development, but remained strongest in the coronary vascular endothelial and cardiac conduction tissues. The arteriolar smooth muscle of the chicken expressed α1 connexin throughout development, but its myocardium did not. In contrast, the working myocardium of a marsupial mammal (the opossum Trichosurus) strongly expressed an α1 connexin just like placental mammals. These results imply that a shift from β1 to α1 connexin expression in the heart occurred prior to the evolution of the opossums. The β and α connexin subfamilies have different permeabilities and gating properties, and we discuss factors that might have made this shift beneficial.
CALCIUM LEVELS DURING CELL CYCLE CORRELATE WITH CELL FATE OF DICTYOSTELIUM DISCOIDEUM
Authors: Saran Shweta
Published: October 2002

Levels of intracellular calcium, (Ca2+)i, from different stages of cell cycle of Dictyostelium discoideum were monitored using the fluorescent Ca2+‐sensitive dye, Indo 1. Combinations of Ca2+‐ionophore (A23187) and Ca2+‐chelator (EGTA) resulted in the inhibition of progression of cell cycle. This delay was caused due to block in G2/M→S phase transition of the cell cycle. Rescue of the cell cycle progression was made with 0.5m m of exogenous Ca2+. High (Ca2+)ilevels overlapped with the S‐phase, of the cell cycle.

Results indicate that a high (Ca2+)ilevel during S‐phase is not required for cell cycle progression but for cell‐type choice mechanism at the onset of starvation, and these cells tend to follow the prestalk pathway.
OVEREXPRESSION OF THE TYPE II TRANSFORMING GROWTH FACTOR‐β RECEPTOR INHIBITS FIBROBLAST PROLIFERATION AND ACTIVATES EXTRACELLULAR SIGNAL REGULATED KINASE AND C‐JUN N‐TERMINAL KINASE
Authors: Goldberg Howard J. , Huszár Tamás , Mózes Miklós M. , Rosivall László , Mucsi István
Published: October 2002

Transforming growth factor‐β (TGF‐β) is a bimodal regulator of cellular growth. The cellular effects of TGF‐β depend on the intensity of signals emanating from TGF‐β receptors. Low levels of receptor activity are sufficient to stimulate cell proliferation, while higher degrees of receptor activation are associated with growth inhibition. To study the mechanisms of these effects, a tetracycline‐inducible expression system was used to overexpress type II TGF‐β receptors in NIH 3T3 fibroblasts. Overexpressed type II TGF‐β receptors suppressed fibroblast proliferation elicited by TGF‐β1, fibroblast growth factor (FGF) or platelet‐derived growth factor (PDGF). Accompanying these anti‐proliferative effects, increases in extracellular‐signal regulated kinase (ERK) and c‐Jun N‐terminal kinase (JNK) activity were detected. Furthermore, PDGF α‐, but not PDGF β‐receptor protein levels were reduced by type II TGF‐β receptor overexpression. In conclusion, our system is an excellent tool to study the molecular mechanisms of growth inhibition by TGF‐β in fibroblasts. Activation of JNK and ERK, or modulation of PDGF receptor expression may be involved in this process.
THE NUMBER OF SECRETORY VESICLES REMAINS UNCHANGED FOLLOWING EXOCYTOSIS
Authors: Cho Sang‐Joon , Cho Jinah , Jena Bhanu P.
Published: October 2002

Earlier studies using electron microscopy demonstrate that there is no loss of secretory vesicles following exocytosis. Depletion however, of vesicular contents resulting in the formation of empty or partially empty vesicles is seen in electron micrographs, post exocytosis, in a variety of cells. Our studies using atomic force microscopy (AFM) reveal that following stimulation of secretion, live pancreatic acinar cells having 100–180nm in diameter fusion pores located at the apical plasma membrane, dilate only 25–35% during exocytosis. Since secretory vesicles in pancreatic acinar cells range in size from 200nm to 1200nm in diameter, their total incorporation at the fusion pore, would distend the structure much more then what is observed. These earlier results prompted the current study to determine secretory vesicle dynamics in live pancreatic acinar cells following exocytosis. AFM studies on live acinar cells reveal no loss of secretory vesicle number following exocytosis. Parallel studies using electron microscopy, further confirmed our AFM results. These studies demonstrate that following stimulation of secretion, membrane‐bound secretory vesicles transiently dock and fuse to release vesicular contents.
CHANGES IN ELASTIN‐BINDING PROTEIN IN FIBROBLASTS DERIVED FROM CARDINAL LIGAMENTS OF PATIENTS WITH PROLAPSUS UTERI
Authors: Yamamoto Mari , Akazawa Kenji , Aoyagi Masaru , Yamamoto Naofumi , Yamamoto Kiyotaka
Published: October 2002

Prolapsus uteri in pelvic supportive disorders are common in elderly women, and their etiology remains unclear. We examined elastin‐binding proteins (EBPs) and binding sites in cultured cardinal ligament fibroblasts derived from elderly patients with prolapsus uteri (HPLiF) and compared them with those from age‐matched control subjects (HCLiF). Cell attachment to α‐elastin was significantly lower in HPLiF than in HCLiF. Elastin suppressed the higher proliferative activity at near confluency in HPLiF. The 67‐kDa EBP was detectable in HCLiF, whereas HPLiF expressed a 59‐kDa EBP. The expression of EBP was significantly lower in HPLiF. The synthetic peptide Val‐Gly‐Val‐Ala‐Pro‐Gly (VGVAPG), which contains a recognition sequence for the elastin receptor, inhibited the adhesion of HCLiF to α‐elastin at 10−5–10−4M, but showed no inhibitory activity on the adhesion of HPLiF at 10−5M. These results suggest that fibroblasts derived from elderly women with prolapsus uteri can recognize α‐elastin through interactions with the low‐molecular‐size (59‐kDa) EBP for the sequence VGVAPG with low affinity and may contribute to the loss of supportive function in uterine connective tissues.
THE EXPRESSION PATTERNS OF INTEGRIN SUBUNITS ON HUMAN BREAST TISSUES OBTAINED DURING PREGNANCY
Authors: Suzuki Rami N. , Entwistle Alan , Atherton Amanda J. , Clarke Catherine , Lakhani Sunil R. , O'Hare Michael J.
Published: October 2002

Integrins have been shown to exert regulatory influences on mammary differentiation and morphogenesis in rodent experimental systems. We have, therefore, examined the expression patterns of integrin subunits on human breast tissues obtained at the 12th, 15th and 18th weeks of pregnancy. Myoepithelial cells were positive for all the integrin subunits examined. α2, α6 and β4 showed increased and more defined labelling during pregnancy, indicating that myoepithelial cells and extracellular matrix strengthen their support for the expanding alveoli during pregnancy. Sub‐populations of stromal cells were positive for α1, α3, α6, β1 and β4. On luminal epithelial cells, α1, α2, α3, α6 and β1 were detectable. α2 showed a focal decrease, but the expression patterns of other integrins in luminal cells did not change during pregnancy. Therefore, the expression patterns of most integrins existing prior to pregnancy seem sufficient in this cell type to support the morphological and functional development during early pregnancy.
The Genus Calycidium Stirt.
Authors: Wedin Mats
Published: October 2002

The lichen genus Calycidium Stirt. (Calycidiaceae, Lecanorales, ‘Caliciales’ s. lat.) contains two species: C. cuneatum Stirt., distributed in Australia (Tasmania) and New Zealand, and C. polycarpum (Colenso) Wedin, comb, nov., distributed in Argentina, Australia (Tasmania), Chile and New Zealand. The morphology, chemistry, ecology and distribution of the two species is discussed, as is the taxonomic position of the genus. Calycidium is reported as new to Argentina.
Progressive and Regressive Pedogenesis and Complex Soil Evolution
Authors: Phillips Jonathan D.
Published: October 2002

The simultaneous operation of regressive and progressive pedogenetic pathways raises the possibility that soil evolution may exhibit patterns far richer and more complex than increasing development over time. This possibility is explored via a numerical model incorporating the relative rates of progressive and regressive pedogenesis and feedbacks between these rates and the degree of soil development. This model may exhibit deterministic chaos and sensitive dependence on initial conditions with realistic parameter values. Variations in profile development in a region of the North Carolina Coastal Plain where soil-forming factors are relatively constant is consistent with deterministic chaos. Chaotic soil evolution suggests that soil development may reflect the interplay between progressive and regressive soil-forming processes in addition to—or instead of—the age of a surface or deposit. The former may produce a state of development which is unique to a particular time, sensitively dependent on the (unknown) initial conditions, and not simply related to age. Soils and their genetic signatures as indicators of relative ages and Quaternary environments may need to be reinterpreted in this light.
Missing Records and Depositional Breaks in French Late Pleistocene Cave Sediments
Authors: Campy Michel , Chaline Jean
Published: October 2002

Cave entrance and rock shelter infillings are positioned within the Pleistocene chronology for three areas of France (northern Alps, Franche-Comté, and Périgord). Despite minor local variations, it is possible to identify regional types with a consistent depositional record over long intervals of time. The interregional variability relates to the frequency and position of the gaps within the infillings. Sites in the northern Alps have not yielded any artifacts older than the Upper Paleolithic (Magdalenı́an), and dated sedimentary sequences do not go back beyond the Older Dryas. More complete sequences in Franche-Comté contain Mousterian industries. Two major gaps occur here, one lasting about 50,000 yr during the Lower Glacial and Lower Pleniglacial periods, and the other lasting some 10,000 yr during the Upper Pleniglacial. The sequences are more complete in the Périgord, where all major climatic phases have been identified with no significant sedimentary gaps. Differences in sedimentary records can be explained by variations in regional conditions during the last interglacial-glacial cycle and especially by the distance from the maximum advance of ice daring glaciation.
A 35,000 Year Vegetation and Climate History from Potato Lake, Mogollon Rim, Arizona
Authors: Anderson R. Scott
Published: October 2002

A new record from Potato Lake, central Arizona, details vegetation and climate changes since the mid-Wisconsin for the southern Colorado Plateau. Recovery of a longer record, discrimination of pine pollen to species groups, and identification of macrofossil remains extend Whiteside's (1965) original study. During the mid-Wisconsin (ca. 35,000-21,000 yr B.P.) a mixed forest of Engelmann spruce (Picea engelmannii) and other conifers grew at the site, suggesting a minimum elevational vegetation depression of ca. 460 m. Summer temperatures were as much as 5°C cooler than today. During the late Wisconsin (ca. 21,000-10,400 yr B.P.), even-cooler temperatures (7°C colder than today; ca. 800 m depression) allowed Engelmann spruce alone to predominate. Warming by ca. 10,400 yr B.P. led to the establishment of the modern ponderosa pine (Pinus ponderosa) forest. Thus, the mid-Wisconsin was not warm enough to support ponderosa pine forests in regions where the species predominates today. Climatic estimates presented here are consistent with other lines of evidence suggesting a cool and/or wet mid-Wisconsin, and a cold and/or wet late-Wisconsin climate for much of the Southwest. Potato Lake was almost completely dry during the mid-Holocene, but lake levels increased to near modern conditions by ca. 3000 yr B.P.
The Last Glaciation in Central Magellan Strait, Southernmost Chile
Authors: Clapperton Chalmers M. , Sugden David E. , Kaufman Darrell S. , McCulloch Robert D.
Published: October 2002

Glacial landforms and drift stratigraphy in central Magellan Strait, southernmost Chile, document repeated fluctuations during the last glacial cycle of outlet lobes from an ice cap centered over the southern Andes. The lobes developed comparatively low-gradient profiles because of low basal shear stresses over soft deformable beds and this made them sensitive to even small-scale changes in the mass balance. Such low profiles and rapid calving in deep proglacial lakes during deglaciation may have made the Magellan ice lobe particularly responsive to climatic fluctuations during the last glacial cycle, and to advance and retreat over considerable distances. Study of the glacial landforms and drift stratigraphy has led to the identification of at least five glacier advances to limits at and south of the Segunda Angostura. Fragments of mollusc shells contained in basal till indicate marine incursions between some advances, thus documenting extensive deglaciation. A partial chronology based on amino acid studies and radiocarbon dating suggests that five of these advances occurred during the last glacial cycle. The most extensive advances may have culminated during substages of marine isotope stage 5 (substage 5b or 5d) and/or during stage 4. Slightly less extensive advances occurred between ca. 28,000 and 14,000 yr B.P.
Late Wisconsin/Early Holocene Vegetation in the Bonneville Basin
Authors: Rhode David , Madsen David B.
Published: October 2002

Woodrat middens from the northern Bonneville Basin allow a reconstruction of vegetation changes from 14,000 to 9000 yr ago. Cold montane steppe, dominated by sagebrush, covered much of the western Bonneville Basin prior to 13,000 yr ago. From 13,000-10,800 yr ago, the region was vegetated by limber pine woodlands in lower montane settings and a mosaic of limber pine and sagebrush steppe along basin flour margins. These low-elevation limber pine woodlands began to retreat upslope after about 11,000 yr ago due to increasingly drier climatic conditions, and were replaced by relatively more xeric desert scrub dominated by sagebrush and shadscale. The growth of limber pine at low elevations suggests that summer temperatures were as much as 6°C lower than at present. This evidence is in apparent conflict with the currently accepted post-Provo Lake Bonneville chronology, especially the magnitude of the postulated near-dessication of Lake Bonneville from ca. 13,000-12,200 yr ago.