bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of a soybean cytochrome P450 monooxygenase cDNA in yeast and tobacco enhances the metabolism of phenylurea herbicides
Authors: Siminszky Balazs , Corbin Frederick T. , Ward Eric R. , Fleischmann Thomas J. , Dewey Ralph E.
Published: July 2002

A strategy based on the random isolation and screening of soybean
cDNAs encoding cytochrome P450 monooxygenases (P450s) was used in an
attempt to identify P450 isozymes involved in herbicide metabolism.
Nine full-length (or near-full-length) P450 cDNAs representing eight
distinct P450 families were isolated by using PCR-based technologies.
Five of the soybean P450 cDNAs were expressed successfully in yeast,
and microsomal fractions generated from these strains were tested for
their potential to catalyze the metabolism of 10 herbicides and 1
insecticide.
In vitro
enzyme assays showed that the gene
product of one heterologously expressed P450 cDNA (CYP71A10)
specifically catalyzed the metabolism of phenylurea herbicides,
converting four herbicides of this class (fluometuron, linuron,
chlortoluron, and diuron) into more polar compounds. Analyses of the
metabolites suggest that the CYP71A10 encoded enzyme functions
primarily as an
N
-demethylase with regard to
fluometuron, linuron, and diuron, and as a ring-methyl hydroxylase when
chlortoluron is the substrate.
In vivo
assays using
excised leaves demonstrated that all four herbicides were more readily
metabolized in CYP71A10-transformed tobacco compared with control
plants. For linuron and chlortoluron, CYP71A10-mediated herbicide
metabolism resulted in significantly enhanced tolerance to these
compounds in the transgenic plants.
Mutations in the nebulin gene associated with autosomal recessive nemaline myopathy
Authors: Pelin Katarina , Hilpelä Pirta , Donner Kati , Sewry Caroline , Akkari Patrick A. , Wilton Stephen D. , Wattanasirichaigoon Duangrurdee , Bang Marie-Louise , Centner Thomas , Hanefeld Folker , Odent Sylvie , Fardeau Michel , Urtizberea J. Andoni , Muntoni Francesco , Dubowitz Victor , Beggs Alan H. , Laing Nigel G. , Labeit Siegfried , de la Chapelle Albert , Wallgren-Pettersson Carina
Published: July 2002

The congenital nemaline myopathies are rare hereditary muscle disorders characterized by the presence in the muscle fibers of nemaline bodies consisting of proteins derived from the Z disc and thin filament. In a single large Australian family with an autosomal dominant form of nemaline myopathy, the disease is caused by a mutation in the α-tropomyosin gene
TPM3
. The typical form of nemaline myopathy is inherited as an autosomal recessive trait, the locus of which we previously assigned to chromosome 2q21.2-q22. We show here that mutations in the nebulin gene located within this region are associated with the disease. The nebulin protein is a giant protein found in the thin filaments of striated muscle. A variety of nebulin isoforms are thought to contribute to the molecular diversity of Z discs. We have studied the 3′ end of the 20.8-kb cDNA encoding the Z disc part of the 800-kDa protein and describe six disease-associated mutations in patients from five families of different ethnic origins. In two families with consanguineous parents, the patients were homozygous for point mutations. In one family with nonconsanguineous parents, the affected siblings were compound heterozygotes for two different mutations, and in two further families with one detected mutation each, haplotypes are compatible with compound heterozygosity. Immunofluorescence studies with antibodies specific to the C-terminal region of nebulin indicate that the mutations may cause protein truncation possibly associated with loss of fiber-type diversity, which may be relevant to disease pathogenesis.
Iron availability dramatically alters the distribution of ferritin subunit messages in
Drosophila melanogaster
Authors: Georgieva Teodora , Dunkov Boris C. , Harizanova Nedjalka , Ralchev Kiril , Law John H.
Published: July 2002

Insect ferritins have subunits homologous to the heavy and light chains of vertebrate ferritins. Cloning and sequence of the heavy chain homologue (HCH) of
Drosophila melanogaster
ferritin subunit have been reported earlier. When Northern blots of
D. melanogaster
RNA were probed with a cDNA for this HCH, three bands were observed. It was shown that these represented at least four classes of mRNA of various lengths. The polymorphism results from alternative splicing of an intron in the 5′ untranslated region (UTR) that contains the iron-responsive element (IRE) and from two alternative polyadenylation sites in the 3′ UTR. This has also been reported by others [Lind, M. I., Ekengren, S., Melefors, Ö. & Söderhäll, K. (1998)
FEBS Lett.
436, 476–482]. By hybridizing Northern blots with specific probes, it has been shown that the relative proportions of the messages vary with the life stage and especially with iron supplementation of the diet. Iron significantly increases the amount of ferritin HCH messages and dramatically shifts the balance toward those messages that lack an IRE and/or have a short 3′ UTR. In the larvae this change takes place in the gut, but not in the fat body. We speculate that this dramatic shift in message distribution may result from an effect of iron on the rate of transcription or message degradation, or from an effect on the splicing process itself. Synthesis of ferritin HCH subunit mRNAs that lack an IRE may be important under conditions of iron overload.
Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits
Authors: Kittles Rick A. , Long Jeffrey C. , Bergen Andrew W. , Eggert Monica , Virkkunen Matti , Linnoila Markku , Goldman David
Published: July 2002

Association between Y chromosome haplotype variation and alcohol dependence and related personality traits was investigated in a large sample of psychiatrically diagnosed Finnish males. Haplotypes were constructed for 359 individuals using alleles at eight loci (seven microsatellite loci and a nucleotide substitution in the DYZ3 alphoid satellite locus). A cladogram linking the 102 observed haplotype configurations was constructed by using parsimony with a single-step mutation model. Then, a series of contingency tables nested according to the cladogram hierarchy were used to test for association between Y haplotype and alcohol dependence. Finally, using only alcohol-dependent subjects, we tested for association between Y haplotype and personality variables postulated to define subtypes of alcoholism—antisocial personality disorder, novelty seeking, harm avoidance, and reward dependence. Significant association with alcohol dependence was observed at three Y haplotype clades, with significance levels ofP= 0.002,P= 0.020, andP= 0.010. Within alcohol-dependent subjects, no relationship was revealed between Y haplotype and antisocial personality disorder, novelty seeking, harm avoidance, or reward dependence. These results demonstrate, by using a fully objective association design, that differences among Y chromosomes contribute to variation in vulnerability to alcohol dependence. However, they do not demonstrate an association between Y haplotype and the personality variables thought to underlie the subtypes of alcoholism.
Motility of ActA protein-coated microspheres driven by actin polymerization
Authors: Cameron Lisa A. , Footer Matthew J. , van Oudenaarden Alexander , Theriot Julie A.
Published: July 2002

Actin polymerization is required for the generation of motile force at the leading edge of both lamellipodia and filopodia and also at the surface of motile intracellular bacterial pathogens such as
Listeria monocytogenes
. Local catalysis of actin filament polymerization is accomplished in
L. monocytogenes
by the bacterial protein ActA. Polystyrene beads coated with purified ActA protein can undergo directional movement in an actin-rich cytoplasmic extract. Thus, the actin polymerization-based motility generated by ActA can be used to move nonbiological cargo, as has been demonstrated for classical motor molecules such as kinesin and myosin. Initiation of unidirectional movement of a symmetrically coated particle is a function of bead size and surface protein density. Small beads (≤0.5 μm in diameter) initiate actin-based motility when local asymmetries are built up by random fluctuations of actin filament density or by thermal motion, demonstrating the inherent ability of the dynamic actin cytoskeleton to spontaneously self-organize into a polar structure capable of generating unidirectional force. Larger beads (up to 2 μm in diameter) can initiate movement only if surface asymmetry is introduced by coating the beads on one hemisphere. This explains why the relatively large
L. monocytogenes
requires polar distribution of ActA on its surface to move.
Reactive oxygen species and nitric oxide mediate plasticity of neuronal calcium signaling
Authors: Yermolaieva Olena , Brot Nathan , Weissbach Herbert , Heinemann Stefan H. , Hoshi Toshinori
Published: July 2002

Reactive oxygen species (ROS) and nitric oxide (NO) are important participants in signal transduction that could provide the cellular basis for activity-dependent regulation of neuronal excitability. In young rat cortical brain slices and undifferentiated PC12 cells, paired application of depolarization/agonist stimulation and oxidation induces long-lasting potentiation of subsequent Ca
2+
signaling that is reversed by hypoxia. This potentiation critically depends on NO production and involves cellular ROS utilization. The ability to develop the Ca
2+
signal potentiation is regulated by the developmental stage of nerve tissue, decreasing markedly in adult rat cortical neurons and differentiated PC12 cells.
A route to hierarchical materials based on complexes of metallosupramolecular polyelectrolytes and amphiphiles
Authors: Kurth Dirk G. , Lehmann Pit , Schütte Markus
Published: July 2002

Anisotropic thin film materials of metallosupramolecular polyelectrolyte–amphiphile complexes (denoted PACs) with structures at several length scales were fabricated through a multistep self-assembly process. Metal ion-mediated self-assembly of the ditopic ligand 1,4-bis(2,2′:6′,2′′-terpyridine-4′-yl)benzene and electrostatic binding with the amphiphile dihexadecyl phosphate result in a PAC with tailored surface chemical properties, including solubility and surface activity. The PAC forms a stable monolayer at the air–water interface that is readily transferred and oriented on solid supports with the Langmuir–Blodgett technique. The presented strategy unifies colloid and metallosupramolecular chemistry and opens a versatile route to hierarchical materials with tailored structures and functions.
Absence of muscarinic cholinergic airway responses in mice deficient in the cyclic nucleotide phosphodiesterase PDE4D
Authors: Hansen Gesine , Jin S.-L. Catherine , Umetsu Dale T. , Conti Marco
Published: July 2002

Muscarinic cholinergic signaling plays an essential role in the control of the normal airway functions and in the development of pulmonary pathologies including asthma. In this paper we demonstrate that the airways of mice deficient in a cAMP-specific phosphodiesterase (PDE4D) are no longer responsive to cholinergic stimulation. Airway hyperreactivity that follows exposure to antigen was also abolished in PDE4D−/−mice, despite an apparently normal lung inflammatory infiltration. The loss of cholinergic responsiveness was specific to the airway, not observed in the heart, and was associated with a loss of signaling through muscarinic receptors with an inability to decrease cAMP accumulation. These findings demonstrate that thePDE4Dgene plays an essential role in cAMP homeostasis and cholinergic stimulation of the airway, and in the development of hyperreactivity. In view of the therapeutic potentials of PDE4 inhibitors, our findings provide the rationale for novel strategies that target a single PDE isoenzyme.
AvrPto-dependent Pto-interacting proteins and AvrPto-interacting proteins in tomato
Authors: Bogdanove Adam J. , Martin Gregory B.
Published: July 2002

The plant-intracellular interaction of the avirulence protein
AvrPto of
Pseudomonas syringae
pathovar tomato, the
agent of bacterial speck disease, and the corresponding tomato
resistance protein Pto triggers responses leading to disease
resistance. Pto, a serine/threonine protein kinase, also interacts
with a putative downstream kinase, Pto-interactor 1, as well as with
members of a family of transcription factors Pto-interactors 4, 5, and
6. These proteins are likely involved, respectively, in a
phosphorylation cascade resulting in hypersensitive cell death, and in
defense gene activation. The mechanism by which the interaction of
AvrPto and Pto initiates defense response signaling is not known. To
pursue the hypothesis that tertiary interactions are involved, we
modified the yeast two-hybrid protein interaction trap and conducted a
search for tomato proteins that interact with Pto only in the presence
of AvrPto. Five classes of AvrPto-dependent Pto interactors were
isolated, and their interaction specificity confirmed. Also, to shed
light on a recently demonstrated virulence activity of AvrPto, we
conducted a standard two-hybrid screen for tomato proteins in addition
to Pto that interact with AvrPto: i.e., potential virulence targets or
modifiers of AvrPto. By constructing an N-terminal rather than a
C-terminal fusion of AvrPto to the LexA DNA binding domain, we were
able to overcome autoactivation by AvrPto and identify four classes of
specific AvrPto-interacting proteins.
Regional and strain-specific gene expression mapping in the adult mouse brain
Authors: Sandberg Rickard , Yasuda Rie , Pankratz Daniel G. , Carter Todd A. , Del Rio Jo A. , Wodicka Lisa , Mayford Mark , Lockhart David J. , Barlow Carrolee
Published: July 2002

To determine the genetic causes and molecular mechanisms
responsible for neurobehavioral differences in mice, we used highly
parallel gene expression profiling to detect genes that are
differentially expressed between the 129SvEv and C57BL/6 mouse
strains at baseline and in response to seizure. In addition, we
identified genes that are differentially expressed in specific brain
regions. We found that approximately 1% of expressed genes are
differentially expressed between strains in at least one region of the
brain and that the gene expression response to seizure is significantly
different between the two inbred strains. The results lead to the
identification of differences in gene expression that may account for
distinct phenotypes in inbred strains and the unique functions of
specific brain regions.
Chemical chaperones mediate increased secretion of mutant α1-antitrypsin (α1-AT) Z: A potential pharmacological strategy for prevention of liver injury and emphysema in α1-AT deficiency
Authors: Burrows Jon A. J. , Willis Lauren K. , Perlmutter David H.
Published: July 2002

In α1-AT deficiency, a misfolded but functionally active mutant α1-ATZ (α1-ATZ) molecule is retained in the endoplasmic reticulum of liver cells rather than secreted into the blood and body fluids. Emphysema is thought to be caused by the lack of circulating α1-AT to inhibit neutrophil elastase in the lung. Liver injury is thought to be caused by the hepatotoxic effects of the retained α1-ATZ. In this study, we show that several “chemical chaperones,” which have been shown to reverse the cellular mislocalization or misfolding of other mutant plasma membrane, nuclear, and cytoplasmic proteins, mediate increased secretion of α1-ATZ. In particular, 4-phenylbutyric acid (PBA) mediated a marked increase in secretion of functionally active α1-ATZ in a model cell culture system. Moreover, oral administration of PBA was well tolerated by PiZ mice (transgenic for the human α1-ATZ gene) and consistently mediated an increase in blood levels of human α1-AT reaching 20–50% of the levels present in PiM mice and normal humans. Because clinical studies have suggested that only partial correction is needed for prevention of both liver and lung injury in α1-AT deficiency and PBA has been used safely in humans, it constitutes an excellent candidate for chemoprophylaxis of target organ injury in α1-AT deficiency.
Defective embryonic neurogenesis in Ku-deficient but not DNA-dependent protein kinase catalytic subunit-deficient mice
Authors: Gu Yansong , Sekiguchi JoAnn , Gao Yijie , Dikkes Pieter , Frank Karen , Ferguson David , Hasty Paul , Chun Jerold , Alt Frederick W.
Published: July 2002

Mammalian nonhomologous DNA end joining employs Ku70, Ku80, DNA-dependent protein kinase catalytic subunit (DNA-PKcs), XRCC4, and DNA ligase IV (Lig4). Herein, we show that Ku70 and Ku80 deficiency but not DNA-PKcs deficiency results in dramatically increased death of developing embryonic neurons in mice. The Ku-deficient phenotype is qualitatively similar to, but less severe than, that associated with XRCC4 and Lig4 deficiency. The lack of a neuronal death phenotype in DNA-PKcs-deficient embryos and the milder phenotype of Ku-deficient versus XRCC4- or Lig4-deficient embryos correlate with relative leakiness of residual end joining in these mutant backgrounds as assayed by a V(D)J recombination end joining assay. We conclude that normal development of the nervous system depends on the four evolutionarily conserved nonhomologous DNA end joining factors.
Fragilities of liquids predicted from the random first order transition theory of glasses
Authors: Xia Xiaoyu , Wolynes Peter G.
Published: July 2002

A microscopically motivated theory of glassy dynamics based on an underlying random first order transition is developed to explain the magnitude of free energy barriers for glassy relaxation. A variety of empirical correlations embodied in the concept of liquid “fragility” are shown to be quantitatively explained by such a model. The near universality of a Lindemann ratio characterizing the maximal amplitude of thermal vibrations within an amorphous minimum explains the variation of fragility with a liquid's configurational heat capacity density. Furthermore, the numerical prefactor of this correlation is well approximated by the microscopic calculation. The size of heterogeneous reconfiguring regions in a viscous liquid is inferred and the correlation of nonexponentiality of relaxation with fragility is qualitatively explained. Thus the wide variety of kinetic behavior in liquids of quite disparate chemical nature reflects quantitative rather than qualitative differences in their energy landscapes.
Dehydroepiandrosterone (DHEA), DHEA sulfate, and aging: Contribution of the DHEAge Study to a sociobiomedical issue
Authors: Baulieu Etienne-Emile , Thomas Guy , Legrain Sylvie , Lahlou Najiba , Roger Marc , Debuire Brigitte , Faucounau Veronique , Girard Laurence , Hervy Marie-Pierre , Latour Florence , Leaud Marie-Céline , Mokrane Amina , Pitti-Ferrandi Hélène , Trivalle Christophe , de Lacharrière Olivier , Nouveau Stephanie , Rakoto-Arison Brigitte , Souberbielle Jean-Claude , Raison Jocelyne , Le Bouc Yves , Raynaud Agathe , Girerd Xavier , Forette Françoise
Published: July 2002

The secretion and the blood levels of the adrenal steroid dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) decrease profoundly with age, and the question is posed whether administration of the steroid to compensate for the decline counteracts defects associated with aging. The commercial availability of DHEA outside the regular pharmaceutical–medical network in the United States creates a real public health problem that may be resolved only by appropriate long-term clinical trials in elderly men and women. Two hundred and eighty healthy individuals (women and men 60–79 years old) were given DHEA, 50 mg, or placebo, orally, daily for a year in a double-blind, placebo-controlled study. No potentially harmful accumulation of DHEAS and active steroids was recorded. Besides the reestablishment of a “young” concentration of DHEAS, a small increase of testosterone and estradiol was noted, particularly in women, and may be involved in the significantly demonstrated physiological–clinical manifestations here reported. Bone turnover improved selectively in women >70 years old, as assessed by the dual-energy x-ray absorptiometry (DEXA) technique and the decrease of osteoclastic activity. A significant increase in most libido parameters was also found in these older women. Improvement of the skin status was observed, particularly in women, in terms of hydration, epidermal thickness, sebum production, and pigmentation. A number of biological indices confirmed the lack of harmful consequences of this 50 mg/day DHEA administration over one year, also indicating that this kind of replacement therapy normalized some effects of aging, but does not create “supermen/women” (doping).
Activation of calcium entry in human carcinoma A431 cells by store depletion and phospholipase C- dependent mechanisms converge on ICRAC-like calcium channels
Authors: Kaznacheyeva Elena , Zubov Alexander , Gusev Konstantin , Bezprozvanny Ilya , Mozhayeva Galina N.
Published: July 2002

Activation of phospholipase C in nonexcitable cells causes the release of calcium (Ca2+) from intracellular stores and activation of Ca2+influx by means of Ca2+release-activated channels (ICRAC) in the plasma membrane. The molecular identity and the mechanism of ICRACchannel activation are poorly understood. Using the patch–clamp technique, here we describe the plasma membrane Ca2+channels in human carcinoma A431 cells, which can be activated by extracellular UTP, by depletion of intracellular Ca2+stores after exposure to the Ca2+-pump inhibitor thapsigargin, or by loading the cells with Ca2+chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetate. The observed channels display the same conductance and gating properties as previously described Iminchannels, but have significantly lower conductance for monovalent cations than the ICRACchannels. Thus, we concluded that the depletion-activated Ca2+current in A431 cells is supported by ICRAC-like (ICRACL) channels, identical to Imin. We further demonstrated synergism in activation of ICRACLCa2+channels by extracellular UTP and intracellular inositol (1,4,5)-triphosphate (IP3), apparently because of reduction in phosphatidylinositol 4,5-bisphosphate (PIP2) levels in the patch. Prolonged exposure of patches to thapsigargin renders ICRACLCa2+channels unresponsive to IP3but still available to activation by the combined action of IP3and anti-PIP2antibody. Based on these data, we concluded that phospholipase C-mediated and store-operated Ca2+influx pathways in A431 cells converge on the same ICRACLCa2+channel, which can be modulated by PIP2.
Social Justice, Integrated Development Planning and Post-apartheid Urban Reconstruction
Authors: Visser Gustav
Published: July 2002

The paper focuses on the intersection between South African urban reconstruction and the development of social justice debates in urban geography. Drawing on a case study located in the Cape Metropolitan Region of South Africa, this investigation illustrates how decision-makers have implemented a planning strategy referred to as integrated development planning (IDP) to aid post- apartheid urban reconstruction. In so doing, the paper shows how this mechanism draws upon the spatial imagination as a method of (re)directing the development of this city. Moreover, the case study demonstrates how an imagined urban space, expressed in the planning system of the IDP, functions as a device by which shared understandings of social justice are enabled. Finally, the paper reflects on how these findings might (re)direct the theoretical development of the social justice concept in geographical and urban planning debates.
Information Technology Consultancy Firms: Economies of Agglomeration from a Wide-area Perspective
Authors: Moulaert Frank , Djellal Faridah
Published: July 2002

'Agglomeration economies' remains a powerful concept in spatial analysis. However, in order to keep its full relevance for contemporary urban and regional systems, it must be completed in two ways. First of all, its qualitative nature, consisting of specific and general assets offered by the urban agglomeration, should be used to enrich the notion of economic externalities. Secondly, agglomeration economies must be considered as the external economies generated by urban agglomerations belonging to different wide-area networks linking high-level urban centres with each other. From this point of view, economies of scale and scope are achieved by multi-locational, knowledge-intensive firms whose functional and spatial organisation is based on the application of principles as: professional collaboration in loosely coupled networks, horizontal communication, optimisation of 'economies of overview', global marketing for locally managed niche markets. This functional and spatial organisation is illustrated for global information technology consultancy (ITC) firms. The spatial logic in the functional division of labour of such firms is strongly influenced by market forces at the level of large agglomerations, which are locations of headquarters of large client firms. But at the same time, this logic also follows the specific structuring principles of internal or support functions of the firms, i.e. R&D, technology and methodology, marketing and internal training. Different types of ITC firm show a variety of forms in their spatial organisation. This is due to the place of ITC in their overall activities, their professional origin (accountancy, organisation and management consulting, systems development, computer and communication hardware production) and the spatial reach of their markets. Still, the spatial organisation of these firms follows the logic of economic externalities offered by top-tier urban agglomerations integrated in wide-area networks. Market expansion happens via globalisation and the creation of new niche markets by existing consulting offices, rather than by the establishment of new offices in lower-tier urban centres.
New Urban Eras and Old Technological Fears: Reconfiguring the Goodwill of Electronic Things
Authors: Thrift Nigel
Published: July 2002

The literature on electronic telecommunications technologies has been infected by the virus of new era thinking, a virus which is simply another variant of technological determinism. This paper is an attempt to expose this virus and it is in four parts. The doubled introduction questions the idea of novelty by paying attention to current writings on 'cyberspace'. The second part of the paper then extends these introductory comments by considering the way in which technological determinism was used to explain the electronic communication technologies of the 19th and early 20th centuries. It is argued that these same habits persist in current writings on the effects of 'new' electronic communication technologies. The third part of the paper illustrates some of these arguments by reference to the history of one of the most concentrated examples of informational space, the City of London. Finally, the doubled conclusion points to what does seem to be novel about the current technological conjuncture by attempting to listen to historical experience.
Spatial Variation in Office Rents within the Atlanta Region
Authors: Bollinger Christopher R. , Ihlanfeldt Keith R. , Bowes David R.
Published: July 2002

Hedonic office rent models are estimated using data for Atlanta that span the years 1990-96. Controlling for typical building characteristics and lease terms, we find that variables measuring locational differences in wage rates, transport rates and proximity to concentrations of support services and office workers play an important role in explaining spatial variation in office rents. No evidence is found in support of the hypothesis that technological advances in telecommunications have diminished the role played by face-to-face agglomeration economies in determining the intra-metropolitan location of office firms.
Gender stereotyping in infancy: Visual preferences for and knowledge of gender-stereotyped toys in the second year
Authors: Serbin Lisa A. , Poulin-Dubois Diane , Colburne Karen A. , Sen Maya G. , Eichstedt Julie A.
Published: July 2002

Infants’ visual preferences for gender-stereotyped toys and their knowledge of stereotyped toys were examined in two experiments using an adaptation of the preferential looking paradigm. Girls and boys aged 12, 18, and 24 months were tested for their preference for photos of vehicles or dolls, and for whether they associated (“matched”) these two stereotyped sets of toys with the faces and voices of male and female children. Results of Experiment 1 (N = 77) demonstrated significant preferences for gender stereotyped toys appearing by 18 months of age. In Experiment 2 (N = 58), girls were able to associate the gender-stereotyped toys with girls’ and boys’ faces by 18 months of age, but boys were not. Implications for theories of early gender development are discussed.
Children’s emotional experience of peer provocation: The relation between observed behaviour and self-reports of emotions, expressions, and social goals
Authors: Underwood Marion K. , Bjornstad Gretchen J.
Published: July 2002

For an experimental study of children’s responses to peer provocation, this investigation examined the correlations between children’s observed behaviours and their self-reports of their emotional experiences, expressions, and social goals provided in an interview immediately following the provocation. Participants were 565 children (approximate ages 8, 10, and 12 years old) who were provoked in two ways in an experimental play session: By losing at a computer game they were playing for a desirable prize, and by being taunted by a peer actor. Children’s responses to provocation were reliably coded for verbalisations, facial expressions, and gestures. Results indicated often significant but quite modest correlations between children’s self-reports of their emotional behaviour and their behaviours as coded during the play session. For the magnitude of these correlations, there were not significant developmental differences, and the strength of the correlations did not differ for same- or for other-gender dyads. There was some evidence that for girls, self-reports corresponded to emotional behaviours more strongly than for boys.
Children’s Salivary Cortisol, Internalising Behaviour Problems, and Family Environment: Results from the Concordia Longitudinal Risk Project
Authors: Granger Douglas A. , Serbin Lisa A. , Schwartzman Alex , Lehoux Pascale , Cooperman Jessica , Ikeda Sandra
Published: July 2002

To explore the possibility that children’s adrenocortical reactions to parent-child conflict influence their vulnerability for internalising behaviour problems, we studied 62 mother-child dyads from the Concordia Longitudinal Risk Project. Standardised measures of maternal, child, and family adjustment were collected. Mother’s and children’s saliva was sampled before and after a conflict-oriented mother-child interaction task and was later assayed for cortisol. The children’s pre-task cortisol scores were negatively associated with their internalising behaviour problems, their mother’s childhood levels of socially withdrawn behaviour and current psychosocial problems, as well as dimensions of family environment representing the open expression of aggression, anger, and conflict. Children’s cortisol levels after the interaction task were lowest for those raised by mothers with high childhood levels of aggressive behaviour problems, and in family environments characterised by rigid rules. Interrelationships between mother and child pre- and post-task cortisol levels were associated with maternal levels of childhood behaviour problems. The integration of measures of children’s adrenocortical activity into developmental studies of children at risk for psychosocial problems may reveal important clues regarding the processes by which adverse early rearing environments affect children’s internalising problem behaviour.
Carcinogenicity of Bromodichloromethane Administered in Drinking Water to Male F344/N Rats and B6C3F1 Mice
Authors: George Michael H. , Olson Greg R. , Doerfler Donald , Moore Tanya , Kilburn Steve , De Angelo Anthony B.
Published: July 2002

A life-time exposure study was conducted to assess the carcinogenicity of bromodichloromethane (BDCM) administered in the drinking water to male F344/N rats and B6C3F1 mice. In mouse, the calculated mean daily BDCM concentrations (measured concentrations corrected for on-cage loss of chemical) were 0.06, 0.28 and 0.49 g/l. Time-weighted water consumption of 135, 97, and 89 ml/kg/day resulted in mean daily doses of 8.1, 27.2, and 43.4 mg BDCM/kg/day. No changes in feed consumption, final body weight, or survival were observed. Kidney weights were significantly depressed at 27.2 and 43.4 mg BDCM/kg/day. There was no increase in neoplasia in the liver, kidney, spleen, testis, bladder, sections along the alimentary tract, excised lesions, or at any other organ site. In rat, the corrected mean daily BDCM concentrations were 0.06, 0.33, and 0.62 g/l. Time-weighted water consumption of 65, 63, and 59 ml/kg/day yielded 3.9, 20.6 and 36.3 mg BDCM/kg/day. No alterations in feed consumption, body weight gain, and survival were seen. Kidney weight was significantly depressed in the 36.3-mg/kg/day treatment group. There was a significantly enhanced prevalence and multiplicity of hepatocellular adenomas at 3.9 mg BDCM/kg/day (15.5% and 0.16/animal vs. 2.2% and 0.02/animal for the control). Hepatocellular carcinomas increased from 2.2% and 0.02/animal for the control and 3.9 mg BDCM/kg/day to 8.3% and 0.10/animal at 20.6 mg BDCM/kg/day. The combined neoplasms were enhanced at 3.9 and 20.6 mg BDCM/kg/day. Liver neoplasia was depressed to the control value at 36.3 mg BDCM/kg. The prevalence of basophilic and clear cell, but not eosinophilic cells, altered foci of cells declined with increasing dose. BDCM did not increase cancer in the large bowel, renal tubules, or in any of the other tissues examined. Renal tubular hyperplasia was observed at 36.3 mg BDCM/kg (15.8% vs. 8.7% for the control group). Under the conditions of the study, BDCM in the drinking water was not carcinogenic in the male B6C3F1 mouse, but was carcinogenic in the male F344/N rat based on an increased hepatocellular neoplasia.
Drugs and Chemicals that Affect the Endocrine System
Authors: Thomas John A.
Published: July 2002

The mammalian endocrine system is very dynamic, and undergoes frequent physiological fluctions due to diurnal variations and cyclical hormonal feedback systems. Both hormonal modulations and chemicall drug perturbations can affect the reproductive systems in males and females. An endocrine disrup-tor, a contemporary term that has been used to define an agent that disrupts the endocrine system, is a hormone or antihormone mimic that can modulate endocrine signaling pathways. Unfortunately, this terminology is confusing and ambiguous and fails to account for the ever-changing endogenous hormonal milieu. The endocrine system can be disrupted or modulated by many physiologic events (e.g., exercise, menstruation, pregnancy), by pharm acologic intervention (e.g., oral contraceptives, antithyroidal medication), and by nutritional states (e.g., iodine deficiencies, vitamin deficiencies and malnutrition). Seasonal changes (e.g., light and temperature) can also modulate endocrine events. Phytoestrogens and xenoestrogens (e.g., chlorinated pesticides) can also affect the dynamics of the endocrine system. Heavy metals and certain anti-cancer agents can interfere with testicular and ovarian function and may cause sterility. Several sites of action can be involved between a drug/chemical and the endocrine system, including the central nervous system, specific target organs or subpopulation of cells, hormone-transporting proteins, and xenobi-otic-m etabolizing enzymes in the liver. At the endocrine target organ level, mechanism(s) of action may involve competition for a cell receptor or affect non-receptor-mediated actions. Some drug!chemicals may act as hormone agonists (i.e., mimic) or conversely act as hormone antagonists (i.e., an antihormone); other agents may act as partial agonists or partial antagonists. Clearly, there are many internal and external factors that can modulate the endocrine system, yet the paracrine and autocrine regulation of specific target organs is finely regulated, and, importantly, is very resilient to drugl chemical perturbation.
Epidemiological Studies and Effects of Environmental Estrogens
Authors: Waddell William J.
Published: July 2002

Increases in cancer of the testis, breast, and prostate have been noted recently, and these increases have often been attributed to a ubiquitous exposure to endocrine-modulating substances. In an effort to either prove or refute these associations, morbidities of (and mortalities from) certain hormonally responsive organs are reviewed. Cancer of the breast, ovary, uterus, cervix, prostate, and testis were selected for comparison and analysis of trends in incidence and mortality. The incidences of cryptorchidism and hypospadias were selected as birth defects representative of possible effects from in utero exposure to excessive estrogens. Sperm counts and endom etriosis were selected as other possible indicators of environmental estrogen effects. Wide, sometimes orders of magnitude, variability exists between incidences in some indicators between different geographical areas and between ethnic groups. Some explanations unrelated to environmental exposures are apparent, and some observations contradict a universal exposure to the same endocrine-modulating substance. In addition, wide differences in incidences exist among virtually adjacent geographical areas and between ethnic groups living in the same geographic area. The data available at present do not lead to the conclusion that endocrine-modulating substances account for worldwide trends in these epidem iological studies.
A Mouse Cytoplasmic Exoribonuclease (mXRN1p) with Preference for G4 Tetraplex Substrates
Authors: Bashkirov Vladimir I. , Scherthan Harry , Solinger Jachen A. , Buerstedde Jean-Marie , Heyer Wolf-Dietrich
Published: July 2002

Exoribonucleases are important enzymes for the turnover of cellular RNA species. We have isolated the first mammalian cDNA from mouse demonstrated to encode a 5′–3′ exoribonuclease. The structural conservation of the predicted protein and complementation data in Saccharomyces cerevisiae suggest a role in cytoplasmic mRNA turnover and pre-rRNA processing similar to that of the major cytoplasmic exoribonuclease Xrn1p in yeast. Therefore, a key component of the mRNA decay system in S. cerevisiae has been conserved in evolution from yeasts to mammals. The purified mouse protein (mXRN1p) exhibited a novel substrate preference for G4 RNA tetraplex–containing substrates demonstrated in binding and hydrolysis experiments. mXRN1p is the first RNA turnover function that has been localized in the cytoplasm of mammalian cells. mXRN1p was distributed in small granules and was highly enriched in discrete, prominent foci. The specificity of mXRN1p suggests that RNAs containing G4 tetraplex structures may occur in vivo and may have a role in RNA turnover.
Integral Membrane Proteins of the Nuclear Envelope Are Dispersed throughout the Endoplasmic Reticulum during Mitosis
Authors: Yang Li , Guan Tinglu , Gerace Larry
Published: July 2002

We have analyzed the fate of several integral membrane proteins of the nuclear envelope during mitosis in cultured mammalian cells to determine whether nuclear membrane proteins are present in a vesicle population distinct from bulk ER membranes after mitotic nuclear envelope disassembly or are dispersed throughout the ER. Using immunofluorescence staining and confocal microscopy, we compared the localization of two inner nuclear membrane proteins (laminaassociated polypeptides 1 and 2 [LAP1 and LAP2]) and a nuclear pore membrane protein (gp210) to the distribution of bulk ER membranes, which was determined with lipid dyes (DiOC6 and R6) and polyclonal antibodies. We found that at the resolution of this technique, the three nuclear envelope markers become completely dispersed throughout ER membranes during mitosis. In agreement with these results, we detected LAP1 in most membranes containing ER markers by immunogold electron microscopy of metaphase cells. Together, these findings indicate that nuclear membranes lose their identity as a subcompartment of the ER during mitosis. We found that nuclear lamins begin to reassemble around chromosomes at the end of mitosis at the same time as LAP1 and LAP2 and propose that reassembly of the nuclear envelope at the end of mitosis involves sorting of integral membrane proteins to chromosome surfaces by binding interactions with lamins and chromatin.
A Sponge-like Structure Involved in the Association and Transport of Maternal Products during Drosophila Oogenesis
Authors: Wilsch-Bräuninger Michaela , Schwarz Heinz , Nüsslein-Volhard Christiane
Published: July 2002

Localization of maternally provided RNAs during oogenesis is required for formation of the antero–posterior axis of the Drosophila embryo. Here we describe a subcellular structure in nurse cells and oocytes which may function as an intracellular compartment for assembly and transport of maternal products involved in RNA localization. This structure, which we have termed “sponge body,” consists of ER-like cisternae, embedded in an amorphous electron-dense mass. It lacks a surrounding membrane and is frequently associated with mitochondria. The sponge bodies are not identical to the Golgi complexes. We suggest that the sponge bodies are homologous to the mitochondrial cloud in Xenopus oocytes, a granulo-fibrillar structure that contains RNAs involved in patterning of the embryo.

Exuperantia protein, the earliest factor known to be required for the localization of bicoid mRNA to the anterior pole of the Drosophila oocyte, is highly enriched in the sponge bodies but not an essential structural component of these. RNA staining indicates that sponge bodies contain RNA. However, neither the intensity of this staining nor the accumulation of Exuperantia in the sponge bodies is dependent on the amount of bicoid mRNA present in the ovaries. Sponge bodies surround nuage, a possible polar granule precursor. Microtubules and microfilaments are not present in sponge bodies, although transport of the sponge bodies through the cells is implied by their presence in cytoplasmic bridges. We propose that the sponge bodies are structures that, by assembly and transport of included molecules or associated structures, are involved in localization of mRNAs in Drosophila oocytes.
Microtubule Stabilization in Pressure Overload Cardiac Hypertrophy
Authors: Sato Hiroshi , Nagai Toshio , Kuppuswamy Dhandapani , Narishige Takahiro , Koide Masaaki , Menick Donald R. , Cooper George
Published: July 2002

Increased microtubule density, for which microtubule stabilization is one potential mechanism, causes contractile dysfunction in cardiac hypertrophy. After microtubule assembly, α-tubulin undergoes two, likely sequential, time-dependent posttranslational changes: reversible carboxy-terminal detyrosination (Tyr-tubulin ↔ Glu-tubulin) and then irreversible deglutamination (Glu-tubulin → Δ2-tubulin), such that Glu- and Δ2-tubulin are markers for long-lived, stable microtubules. Therefore, we generated antibodies for Tyr-, Glu-, and Δ2-tubulin and used them for staining of right and left ventricular cardiocytes from control cats and cats with right ventricular hypertrophy. Tyr- tubulin microtubule staining was equal in right and left ventricular cardiocytes of control cats, but Glu-tubulin and Δ2-tubulin staining were insignificant, i.e., the microtubules were labile. However, Glu- and Δ2-tubulin were conspicuous in microtubules of right ventricular cardiocytes from pressure overloaded cats, i.e., the microtubules were stable. This finding was confirmed in terms of increased microtubule drug and cold stability in the hypertrophied cells. In further studies, we found an increase in a microtubule binding protein, microtubule-associated protein 4, on both mRNA and protein levels in pressure-hypertrophied myocardium. Thus, microtubule stabilization, likely facilitated by binding of a microtubule-associated protein, may be a mechanism for the increased microtubule density characteristic of pressure overload cardiac hypertrophy.
The Yeast Centrin, Cdc31p, and the Interacting Protein Kinase, Kic1p, Are Required for Cell Integrity
Authors: Sullivan Donald S. , Biggins Sue , Rose Mark D.
Published: July 2002

Cdc31p is the yeast homologue of centrin, a highly conserved calcium-binding protein of the calmodulin superfamily. Previously centrins have been implicated only in microtubule-based processes. To elucidate the functions of yeast centrin, we carried out a two-hybrid screen for Cdc31p-interacting proteins and identified a novel essential protein kinase of 1,080 residues, Kic1p (kinase that interacts with Cdc31p). Kic1p is closely related to S. cerevisiae Ste20p and the p-21– activated kinases (PAKs) found in a wide variety of eukaryotic organisms. Cdc31p physically interacts with Kic1p by two criteria; Cdc31p coprecipitated with GST–Kic1p and it bound to GST–Kic1p in gel overlay assays. Furthermore, GST–Kic1p exhibited in vitro kinase activity that was CDC31-dependent. Although kic1 mutants were not defective for spindle pole body duplication, they exhibited a variety of mutant phenotypes demonstrating that Kic1p is required for cell integrity. We also found that cdc31 mutants, previously identified as defective for spindle pole body duplication, exhibited lysis and morphological defects. The cdc31 kic1 double mutants exhibited a drastic reduction in the range of permissive temperature, resulting in a severe lysis defect. We conclude that Kic1p function is dependent upon Cdc31p both in vivo and in vitro. We postulate that Cdc31p is required both for SPB duplication and for cell integrity/morphogenesis, and that the integrity/morphogenesis function is mediated through the Kic1p protein kinase.