bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vanadocytes, cells hold the key to resolving the highly selective accumulation and reduction of vanadium in ascidians
Authors: Michibata Hitoshi , Uyama Taro , Ueki Tatsuya , Kanamori Kan 
Published: August 2002

AbstractSince Henze discovered vanadium in the blood (or coelomic) cells of an ascidian in 1911, this unusual phenomenon has attracted the interest of many investigators. The highest concentration of vanadium (350 mM) in the blood cells of Ascidia gemmata, which belongs to the suborder Phlebobranchia, is 107 times higher than that in seawater. Of the approximately 10 types of blood cells, a combination of cell fractionation and neutron‐activation analysis revealed that the signet ring cells were the true vanadocytes. In the vanadocytes, 97.6% of the vanadium is in the +3 oxidation state (III). The extremely low pH of 1.9 found in vanadocytes suggests that protons, concentrated by an H+‐ATPase, might be linked to the accumulation of vanadium energetically. The antigen recognized by a monoclonal antibody, S4D5, prepared to identify vanadocytes, was determined to be 6‐PGDH in the pentose phosphate pathway. NADPH produced in the pentose phosphate pathway in vanadocytes is thought to participate in the reduction of vanadium(V) to vanadium(IV). During embryogenesis, a vanadocyte‐specific antigen first appears in the body wall at the same time that significant accumulations of vanadium become apparent. Three different vanadium‐associated proteins (VAPs) were extracted from the blood cells of vanadium‐rich ascidians. These are 12.5, 15, and 16 kDa in size and are associated with vanadium in an approximate ratio of 1:16. The cDNA encoding the 12.5 and 15 kDa VAPs was isolated and the proteins encoded were found to be novel. Further biochemical and biophysical characterization of the VAPs is in progress. Microsc. Res. Tech. 56:421–434, 2002. © 2002 Wiley‐Liss, Inc.
Cyclic GMP signaling in podocytes
Authors: Lewko Barbara , Stepinski Jan 
Published: August 2002

AbstractNatriuretic peptides (NP), together with nitric oxide (NO) are powerful relaxing factors acting via a common second messenger, cyclic GMP (cGMP). Together with other vasoactive modulators, these vasorelaxing factors play an essential role in regulating the function of kidney glomeruli. The presence of NP receptors in podocytes has been well documented. Recently, also mRNA for soluble guanylate cyclase, the NO receptor, has been shown in these cells. Stimulation of podocytes with atrial natriuretic peptide (ANP), C‐type natriuretic peptide (CNP), and NO donors results in considerable upregulation of cellular cGMP synthesis. The podocyte foot processes contain a highly organized network of microfilaments adhering to the glomerular basement membrane (GBM). Changes in podocyte cytoskeleton accompanied by detachment of the cells from the GBM are closely associated with many glomerulopathies. The contractile apparatus in the podocyte foot processes seems to be an obvious target for the cyclic GMP signaling cascade. However, little is known about implications of the cGMP synthesis in these cells. We briefly review the current art regarding generation and modulation of cyclic GMP levels in podocytes. We discuss also the possible targets for this secondary messenger as well as its functional role in podocytes. Microsc. Res. Tech. 57:232–235, 2002. © 2002 Wiley‐Liss, Inc.
Microglial interaction with β‐amyloid: Implications for the pathogenesis of Alzheimer's disease
Authors: Bamberger Maria E. , Landreth Gary E. 
Published: August 2002

AbstractThe etiology of Alzheimer's disease (AD) involves a significant inflammatory component as evidenced by the presence of elevated levels of a diverse range of proinflammatory molecules in the AD brain. These inflammatory molecules are produced principally by activated microglia, which are found to be clustered within and adjacent to the senile plaque. Moreover, long‐term treatment of patients with non‐steroidal anti‐inflammatory drugs has been shown to reduce risk and incidence of AD and delay disease progression. The microglia respond to beta‐amyloid (Aβ) deposition in the brain through the interaction of fibrillar forms of amyloid with cell surface receptors, leading to the activation of intracellular signal transduction cascades. The activation of multiple independent signaling pathways ultimately leads to the induction of proinflammatory gene expression and production of reactive oxygen and nitrogen species. These microglial inflammatory products act in concert to produce neuronal toxicity and death. Therapeutic approaches focused on inhibition of the microglial‐mediated local inflammatory response in the AD brain offer new opportunities to intervene in the disease. Microsc. Res. Tech. 54:59–70, 2001. © 2001 Wiley‐Liss, Inc.
Peptides in frog brain areas processing visual information
Authors: Lázár Gyula 
Published: August 2002

AbstractVision is the most important sensory modality to anurans and a great deal of work in terms of hodological, physiological, and behavioral studies has been devoted to the visual system. The aim of this account is to survey data about the distribution of peptides in primary (lateral geniculate complex, pretectum, tectum) and secondary (striatum, anterodorsal and anteroventral tegmental nuclei, isthmic nucleus) visual relay centers. The emphasis is on general traits but interspecies variations are also noted. The smallest amount of peptide‐containing neuronal elements was found in the lateral geniculate complex, where primarily nerve fibers showed immunostaining. All peptides found in the lateral geniculate complex, except two, occurred in the pretectum together with four other peptides. A large number of neurons showing intense neuropeptide thyrosine‐like immunoreactivity was characteristic here. The mesencephalic tectum was the richest in peptide‐like immunoreactive neuronal elements. Almost all peptides investigated were present mainly in fibers, but 9 peptides were found also in cells. The immunoreactive fibers show a complicated overlapping laminar arrangement. Cholecystokinin octapeptide, enkephalins, neuropeptide tyrosine, and substance P (not discussed here) gave the most prominent immunoreactivity. Several peptides also occur in the tectum of fishes, reptiles, birds, and mammals. Peptides in various combinations were found in the striatum, the anterodorsal‐ and anteroventral tegmental nucleus, and the isthmic nucleus that receive projections from the primary visual centers. The functional significance of peptides in visual information processing is not known. The only exception is neuropeptide tyrosine, which was found to be inhibitory on retinotectal synapses. Microsc. Res. Tech. 54:201–219, 2001. © 2001 Wiley‐Liss, Inc.
Sex differences in songbirds 25 years later: What have we learned and where do we go?
Authors: Ball Gregory F. , Macdougall‐Shackleton Scott A. 
Published: August 2002

AbstractAbout 25 years ago, Nottebohm and Arnold reported that there are profound male‐biased sex differences in volume in selected nuclei in telencephalic portions of the song control system. This review focuses on issues related to the cellular bases of these sex differences in volume and comparative studies that might elucidate the function of this variation between the sexes. Studies utilizing a variety of neurohistological methods in several different species to define the boundaries of two key telencephalic song nuclei HVc and the robust nucleus of the archistriatum (RA) all tend to find a sex difference in volume in agreement with Nissl‐defined boundaries. Sex differences in volume in nuclei such as HVc and RA are associated with differences in cell size and cell number. Other attributes of the phenotype of cells in these nuclei are also different in males and females such as the number of cells expressing androgen receptors. Comparative studies have been employed to understand the function of these sex differences in the brain. In some songbird species, females sing rarely or not at all, and the brain nuclei that control song are many times larger volume in males than females. In other species, males and females sing approximately equally, and the brain nuclei that control song are approximately equal between the sexes. Recently, statistical methods have been employed to control for phylogenetic effects while comparing the co‐evolution of traits. This analysis indicates that the evolution of sex differences in song has co‐evolved with the evolution of sex differences in singing behavior in songbird species. Future studies should focus on the function of the smaller song control nuclei of females and investigate the role these nuclei might play in perception as well as in production. Microsc. Res. Tech. 54:327–334, 2001. © 2001 Wiley‐Liss, Inc.
Synthesis, distribution, and levels of an egg lipoprotein from the apple snail Pomacea canaliculata (Mollusca: Gastropoda)
Authors: Dreon M. , Lavarias S. , Garin C.F. , Heras H. , Pollero R.J. 
Published: August 2002

AbstractThe site of synthesis of mollusc lipoproteins is hitherto unknown and was investigated for perivitellin 2 (PV2), an egg lipoprotein found in the freshwater snail Pomacea canaliculata. Tissues (albumen gland, gonad–digestive gland complex, and muscle) from vitellogenic females were incubated in vitro with 14C‐leucine at 25°C for 12 hr. At the end of incubation, soluble proteins from tissue homogenates and medium were analyzed for de novo protein synthesis by electrophoresis and HPLC, and radiolabeled proteins were quantified by liquid scintillation. Two albumen gland radiolabeled proteins (67 and 31 kDa) co‐migrated with the subunits of PV2, and they represented 6.0% of the total labeled protein in that tissue. Western blot analysis confirmed the presence of PV2 only in the albumen gland. In vivo experiments where adult females were injected with 3H‐leucine revealed that PV2 was not present in hemolymph. ELISA analysis in all tissues of the snail confirmed the PV2 presence only in the albumen gland and developing eggs with levels of 26 and 98 mg/g protein, respectively. Therefore, the albumen gland is the only site for PV2 synthesis, and no extra‐gland synthesis, circulation, or accumulation could be found. PV2 subunits were further characterized analyzing N‐terminal sequences which showed no homology with other proteins. J. Exp. Zool. 292:323–330, 2002. © 2002 Wiley‐Liss, Inc.
Acid–base regulation in fishes: cellular and molecular mechanisms
Authors: Claiborne James B. , Edwards Susan L. , Morrison‐Shetlar Alison I. 
Published: August 2002

AbstractThe mechanisms underlying acid–base transfers across the branchial epithelium of fishes have been studied for more than 70 years. These animals are able to compensate for changes to internal pH following a wide range of acid–base challenges, and the gill epithelium is the primary site of acid–base transfers to the water. This paper reviews recent molecular, immunohistochemical, and functional studies that have begun to define the protein transporters involved in the acid–base relevant ion transfers. Both Na+/H+ exchange (NHE) and vacuolar‐type H+‐ATPase transport H+ from the fish to the environment. While NHEs have been thought to carry out this function mainly in seawater‐adapted animals, these proteins have now been localized to mitochondrial‐rich cells in the gill epithelium of both fresh and saltwater‐adapted fishes. NHEs have been found in the gill epithelium of elasmobranchs, teleosts, and an agnathan. In several species, apical isoforms (NHE2 and NHE3) appear to be up‐regulated following acidosis. In freshwater teleosts, H+‐ATPase drives H+ excretion and is indirectly coupled to Na+ uptake (via Na+ channels). It has been localized to respiratory pavement cells and chloride cells of the gill epithelium. In the marine elasmobranch, both branchial NHE and H+‐ATPase have been identified, suggesting that a combination of these mechanisms may be utilized by marine elasmobranchs for acid–base regulation. An apically located Cl−/HCO3− anion exchanger in chloride cells may be responsible for base excretion in fresh and seawater‐adapted fishes. While only a few species have been examined to date, new molecular approaches applied to a wider range of fishes will continue to improve our understanding of the roles of the various gill membrane transport processes in acid–base balance. © 2002 Wiley‐Liss, Inc.
Negative test for cloacal drinking in a semi‐aquatic turtle (Trachemys scripta), with comments on the functions of cloacal bursae
Authors: Peterson Charles C. , Greenshields David 
Published: August 2002

AbstractMany aquatic turtles possess paired evaginations of the cloaca called cloacal bursae. Despite more than two centuries of study, little consensus exists as to the function(s) of these organs. We tested a recent suggestion that bursae could function in water uptake (“cloacal drinking”). Turtles (Trachemys scripta) were dehydrated (68–86% of maximum body mass) and given the opportunity to drink orally or cloacally. Dehydration caused increases in hematocrit and osmolality of extracellular fluid (ECF), but only after loss of 10–12% of maximum body mass, suggesting that turtles osmoregulated by reabsorbing water from the urinary bladder. Turtles drank eagerly when they could submerge their heads, and drinking was accompanied by an increase in body mass and a decrease in ECF osmolality. However, dehydrated turtles with tail and anus submerged showed no changes in mass or osmolality, suggesting that water absorption is not a significant function of the cloacal bursae in this species. Evidence for other putative functions is reviewed, leading to a pluralistic view: in cryptodires, bursae apparently function primarily in buoyancy control and secondarily in ion transport and nesting, but several pleurodires have been shown recently to use them in aquatic respiration.J. Exp. Zool. 290:247–254, 2001. © 2001 Wiley‐Liss, Inc.
Contribution of domestic animals to the identification of new genes involved in sex determination
Authors: Pailhoux Eric , Vigier Bernard , Vaiman Daniel , Schibler Laurent , Vaiman Anne , Cribiu Edmond , Nezer Carine , Georges Michel , Sundström Jari , Pelliniemi Lauri J. , Fellous Marc , Cotinot Corinne 
Published: August 2002

AbstractAmong farm animals, two species present an intersex condition at a relatively high frequency: pig and goat. Both are known to contain XX sex‐reversed individuals which are genetically female but with a true hermaphrodite or male phenotype. It has been clearly demonstrated that the SRY gene is not involved in these phenotypes. Consequently, autosomal or X‐linked mutations in the sex‐determining pathway may explain these sex‐reversed phenotypes. A mutation referred to as “polled” has been characterized in goats by the suppression of horn formation and abnormal sexual differentiation. The Polled Intersex Syndrome locus (PIS) was initially located in the distal region of goat chromosome 1. The homologous human region has been precisely identified as an HSA 3q23 DNA segment containing the Blepharophimosis Ptosis Epicanthus locus (BPES), a syndrome combining Premature Ovarian Failure (POF) and an excess of epidermis of the eyelids.In order to isolate genes involved in pig intersexuality, a similar genetic approach was attempted in pigs using genome scanning of resource families. Genetic analyses suggest that pig intersexuality is controlled multigenically. Parallel to this work, gonads of fetal intersex animals have been studied during development by light and electron microscopy. The development of testicular tissue and reduction of germ cell number by apoptosis, which simultaneously occurs as soon as 50 days post coïtum, also suggests that several separate genes could be involved in pig intersexuality. J. Exp. Zool. 290:700–708, 2001. © 2001 Wiley‐Liss, Inc.
A molecular phylogenetic study of ecological diversification in the Australian lizard genus Ctenophorus
Authors: Melville Jane , Schulte James A. , Larson Allan 
Published: August 2002

AbstractWe present phylogenetic analyses of the lizard genus Ctenophorus using 1,639 aligned positions of mitochondrial DNA sequences containing 799 parsimony‐informative characters for samples of 22 species of Ctenophorus and 12 additional Australian agamid genera. Sequences from three protein‐coding genes (ND1, ND2, and COI) and eight intervening tRNA genes are examined using both parsimony and maximum‐likelihood analyses. Species of Ctenophorus form a monophyletic group with Rankinia adelaidensis, which we suggest placing in Ctenophorus. Ecological differentiation among species of Ctenophorus is most evident in the kinds of habitats used for shelter. Phylogenetic analyses suggest that the ancestral condition is to use burrows for shelter, and that habits of sheltering in rocks and shrubs/hummock grasses represent separately derived conditions. Ctenophorus appears to have undergone extensive cladogenesis approximately 10–12 million years ago, with all three major ecological modes being established at that time. J. Exp. Zool. (Mol. Dev. Evol.) 291:339–353, 2001. © 2001 Wiley‐Liss, Inc.
K4−‐factor in a graph
Authors: Kawarabayashi Ken‐ichi 
Published: August 2002

AbstractLet G be a graph of order 4k and let δ(G) denote the minimum degree of G. Let F be a given connected graph. Suppose that |V(G)| is a multiple of |V(F)|. A spanning subgraph of G is called an F‐factor if its components are all isomorphic to F.In this paper, we prove that if δ(G)≥5/2k, then G contains a K4−‐factor (K4− is the graph obtained from K4 by deleting just one edge). The condition on the minimum degree is best possible in a sense. In addition, the proof can be made algorithmic. © 2002 John Wiley & Sons, Inc. J Graph Theory 39: 111–128, 2002
Brace generation
Authors: McCuaig William 
Published: August 2002

AbstractA brace is a connected bipartite graph with a perfect matching and at least six vertices such that for every pair of nonadjacent edges, there is a perfect matching containing the edges. We give a method for generating all braces. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 124–169, 2001
Privatization in Turkey: Implementation, politics of privatization and performance results
Authors: Karataş Cevat 
Published: August 2002

AbstractThe paper provides a comprehensive survey of privatization transastions in Turkey which took place between 1986 and 2000. The objectives of the privatization programme and privatized and nominated SOEs are discussed. The breakdown of total proceeds by sales methods and scope of the privatization programme by economic sectors are examined. The saleability of relatively large public enterprises is reviewed and utilization of privatization proceeds during and after privatization process is critically appraised. In addition, an attempt is made to discuss the politics of privatization by referring to key political and economic factors which have influenced implementation of the privatization programme. Following a short review of the economic environment and macroeconomic indicators in Turkey, focus is also placed on the research results that are available on the performance of public, private and privatized SOEs, particularly in the cement sector. In the final section, some key issues relevant to Turkish privatization are accentuated and some conclusion are drawn. © 2001 John Wiley & Sons, Ltd.
Resource allocation and priority setting of HIV/AIDS interventions: addressing the generalized epidemic in sub‐Saharan Africa
Authors: Kumaranayake Lilani , Watts Charlotte 
Published: August 2002

AbstractThe endemic nature of HIV/AIDS in Africa has led to substantial activity to intensify action in SSA over the past two years. There has been both a reallocation of resources towards HIV/AIDS and wide scale efforts at mobilizing additional resources to scale up HIV/AIDS prevention and care interventions. Despite efforts to rapidly mobilize resources, priority‐setting among the various interventions remains a central issue, with broad debates about how resources should be allocated, and particular concern about treatment and the availability of drugs. In this paper, we discuss the range of interventions which are commonly implemented for HIV/AIDS and the debate around priority‐setting, in settings where the HIV epidemic is centralised. Copyright © 2001 John Wiley & Sons, Ltd.
A livelihood from the forest: gendered visions of social, economic and environmental change in Southern Cameroon
Authors: Brown Katrina , Lapuyade Sandrine 
Published: August 2002

AbstractThis paper explores divergent perceptions and experiences of social, economic and environmental change of villagers in Southern Cameroon arguing that the economic crisis has impacted very differently on men and women within the same community and within households. The analysis highlights shifts in cropping patterns towards increased food crops, especially cassava and plantain, for cash. Sources of livelihood for men have diversified in the face of economic crisis, whereas women have reduced room to manoeuvre. This results in women becoming increasingly dependent on utilizing non‐timber forest products for cash in order to meet their livelihood needs. However pressures on forest are increasing for a number of reasons and access to land and trees is becoming constrained, so future benefits from forest products will be contingent on clear, well defined and enforced community property rights. Copyright © 2001 John Wiley & Sons, Ltd.
Growth and institutions
Authors: Fedderke Johannes 
Published: August 2002

AbstractAlternative conceptions of the link between social and political institutions and economic growth are explored theoretically and empirically. A number of plausible hypotheses found in the literature are found to have distinct implications for social steady state, including the possibility of low income steady state institutional traps. Empirical evidence suggests considerable heterogeneity between countries in the nature of the link between institutions and economic activity, throwing doubt on the validity of standard cross‐sectional growth equations. The application of cointegration techniques of analysis identifies a number of countries that may prove fruitful as the object of more detailed clinical analysis. Copyright © 2001 John Wiley & Sons, Ltd.
One‐step purification of glucoamylase by affinity precipitation with alginate
Authors: Teotia S. , Lata R. , Khare S. K. , Gupta M. N. 
Published: August 2002

AbstractIt was found that alginate binds to glucoamylase, presumably through the recognition of starch binding domain of the latter. The present work exploits this for purification of glucoamylases from commercial preparation of Aspergillus niger and crude culture filtrate of Bacillus amyloliquefaciens by affinity precipitation technique in a single‐step protocol. Glucoamylase is selectively precipitated using alginate as macroaffinity ligand and later eluted with 1.0 M maltose. In the case of A. niger, 81% activity is recovered with 28‐fold purification. The purified glucoamylase gave a single band on SDS–PAGE corresponding to 78 kDa molecular weight. The developed affinity precipitation process also works efficiently for purification of Bacillus amyloliquefaciens glucoamylase from its crude culture filtrate, giving 78% recovery with 38‐fold purification. The purified preparation showed a major band corresponding to 62 kDa and a faint band about 50 kDa on SDS–PAGE. The latter corresponds to the molecular weight for α‐amylase of Bacillus amyloliquefaciens. Copyright © 2001 John Wiley & Sons, Ltd.