bluuebunny/crossref_metadata_2025 huggingface dataset:
Addison's Empire: Whig Conceptions of Empire in the Early 18th Century
Authors: PINCUS STEVE
Published: February 2012

Why did whigs consider the Treaty of Utrecht to be an imperial disaster? Contemporary scholarship makes this a difficult question to answer. Imperial historians insist that it was an imperial triumph. While political historians point to rough‐and‐tumble party politics that was not about empire. This article aims to recover the rich intellectual history of party political debate about empire in the age of Anne. I suggest that there was bitter conflict between tories who sought territorial empire based on South American mines, and whigs who sought a manufacturing empire based on penetrating South American markets with British manufactures. The Sacheverell trial and its aftermath marked a turning point in British imperial policy. As a result the whigs felt betrayed, venting their anger in the immediate aftermath of the Hanoverian succession.
The ‘End of Censorship’ and the Politics of Toleration, from Locke to Sacheverell
Authors: KEMP GEOFF
Published: February 2012

The end of pre‐publication censorship in England in 1695 is a milestone in the historical self‐image of modern liberal democracy, although historians since at least Macaulay have seen the fall of the Licensing Act as preceding, rather than proceeding from, a principled commitment to press freedom. One outcome has been a routine assumption that the multiple attempts to pass printing legislation in the decade after 1695 tried to restore press licensing, and so censorship. Recent accounts have reinforced this view in tracing a pathway to the 1710 Copyright Act, assuming censorship as a cause of Church and state while focusing on literary property as the cause of print trade and authors. Yet a close reading of the evidence overturns the view that the lapse of censorship in 1695 was followed by a series of licensing bills. Instead, press bills sought compulsory imprints, as Milton's Areopagitica had recommended in 1644 and Locke's circle advocated in 1695. This became, via Defoe, a connecting‐point between religious politics and copyright. This article shows how working from 1695 towards 1710 as the year of the Sacheverell trial provides a new perspective on ‘the end of censorship’, tied to acute post‐revolution division in the Church over toleration and the suppression of heresy. From this perspective, the abandonment of licensing was a Church cause, orchestrated, in part, by the archbishop of Canterbury to outflank high church opponents.
Differentiation of autoimmune pancreatitis with pancreatic carcinoma remains a challenge to physicians
Authors: GONG Pei Li , LIU Tao Tao , SHEN Xi Zhong
Published: February 2012

OBJECTIVE:  The aim of this study was to summarize the clinical features of autoimmune pancreatitis (AIP) and review the advances in the differential diagnosis with pancreatic carcinoma, thus help to make a correct diagnosis and avoid unnecessary surgery in clinical practice.

METHODS:  Five patients diagnosed as AIP in accordance with the HISORt criteria in Zhongshan Hospital, Fudan University from 2008 to 2010 were enrolled in the study. Clinical features were analyzed and related literature was reviewed.

RESULTS:  Progressive jaundice and abdominal pain were the most frequent symptoms, as well as weight loss, together with serological changes such as elevation of alkaline phosphatase, γ‐glutamyl‐transpeptidase and serum bilirubin. Two of them showed high serum immunoglobulin G4 (IgG4) levels. Both focal and diffuse changes were found on computed tomography and magnetic resonance imaging. Two of our patients underwent operation because of a high suspicion of malignant tumor, and steroid therapy was administered to the other three patients diagnosed as AIP. No relapse was observed during the follow‐up duration of all the patients.

CONCLUSIONS:  Although some recent advances have been made to help the diagnosis of AIP, the differentiation between AIP and pancreatic carcinoma is still a challenge. Clinicians must remember to exclude AIP before making a diagnosis of pancreatic carcinoma.
Subfamily composition of Ichneumonidae (Hymenoptera) from western Amazonia: Insights into diversity of tropical parasitoid wasps
Authors: VEIJALAINEN ANU , SÄÄKSJÄRVI ILARI E. , ERWIN TERRY L. , GÓMEZ ISRRAEL C. , LONGINO JOHN T.
Published: February 2012

Abstract.  1. Previous studies have found the parasitoid wasp family Ichneumonidae (Hymenoptera) to have an exceptional latitudinal species richness gradient that peaks at mid‐latitudes instead of the tropics; however, insufficient tropical sampling and species description may have biased the conclusions. It has been unclear which subfamilies might be species rich in tropical lowland rain forests.

2. This study reports the subfamily abundance composition of a large ichneumonid data set (>30 000 individuals in 20 subfamilies) collected by Malaise traps and insecticidal canopy fogging in Amazonian Ecuador and Peru and suggests which subfamilies would be important for future study.

3. Relative abundance data from one Peruvian site are compared to similar lowland samples from Costa Rica and Georgia (USA).

4. Contrary to a common assumption, a number of ichneumonid subfamilies are very abundant and presumably species rich in western Amazonia. Cryptinae and Orthocentrinae are noticeably the two most abundant subfamilies, and a number of koinobiont lepidopteran parasitoids, which are generally thought to be scarce in the tropics, are also surprisingly abundant (e.g. Anomaloninae, Banchinae and Cremastinae). However, the subfamilies whose primary hosts are rare in the tropics (e.g. Ctenopelmatinae, Tryphoninae) can still be expected to be more diverse in the temperate than in tropical zone.

5. Further research on the latitudinal species richness gradient within different ichneumonid subfamilies is encouraged to help understand what factors determine macroecological species richness patterns and what is the total number of ichneumonid species on earth.
Socio‐Economic Factors and Mental Health of Young People in India and China: An Elusive Link with Globalization
Authors: Bhat M. Aslam , Rather Tareak A.
Published: February 2012

Globalization and its related social, cultural, and economic changes have significant mental health outcomes for young people. However, mental health disorders among youth are seldom included in the range of problems linked to globalization. It is imperative that these multifaceted associations are considered in light of the substantial and increasing burden of disease caused by mental illness, particularly in Asian countries, which are comparatively young and in next few decades will be the major sources of the growth of world’s young population. The evidence reviewed in this study makes an argument that globalization has increased [relative] poverty and deprivation, social and income inequality, migration, occupational stress, educational competition, and educated unemployment in India and China. Simultaneously there is evidence which shows that these variables are causally linked with mental health of young people. Altogether, these phenomena are accompanied by higher rates of suicide among lower class, migrant, and student youth. This substantiates the proposition that globalization has significant consequences for the mental health of young people. Some interventions for debate and discussion are considered.
Defining Causes for Overactive Bladder Symptoms in Women
Authors: FAN Yu‐Hua , LIN Alex T. L. , CHEN Kuang‐Kuo
Published: February 2012

Objectives: The aim of the present study was to determine the causes for overactive bladder (OAB) symptoms in women visiting a urological clinic.

Methods: We prospectively recruited female patients with OAB symptoms between December 2008 and February 2010. All patients were interviewed for their detailed personal and medical history. All patients completed a 3‐day frequency‐volume chart. Symptom severity was evaluated using the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) questionnaires. All patients underwent either conventional pressure‐flow urodynamic studies or video‐urodynamic studies. On the basis of these evaluations, patients were assigned to one of the following categories: idiopathic OAB, stress urinary incontinence (SUI)‐associated, neurogenic bladder, or bladder outlet obstruction (BOO).

Results: A total of 108 female patients were recruited into the study. The mean age of the patients was 63.75 ± 14.02 years (range: 23–89). Detrusor overactivity was demonstrated in 55 patients (51%). The differential diagnosis was idiopathic OAB in 51 women (47.2%), SUI‐associated in 46 (42.6%), neurogenic bladder in 13 (12.0%) and BOO in 7 (6.5%).

Conclusion: Our study suggests that the causes for OAB symptoms could be defined in half of the women visiting a urological clinic. Among them, SUI was the most common. Moreover, OAB symptoms in women might relate to BOO. Detailed history taking and sophisticated urodynamic studies are required for a substantial group of female patients with OAB symptoms to make the correct diagnosis and provide optimal therapy.
Stability of cyclin B protein during meiotic maturation and the first mitotic cell division in mouse oocytes
Authors: Winston Nicola J
Published: February 2012

This report examines in detail the metabolism of the cyclin protein B1 during meiotic maturation and following the activation of mature mouse oocytes using immunoprecipitation of the radiolabelled protein. The net synthesis of cyclin B increases progressively during meiotic maturation, reaching its maximum levels at least 1 h before oocytes exit into metaphase of meiosis II (MII). This increase correlates with the rise in cdc2 kinase activity reported previously and suggests an association between the length of the first meiotic M phase (MI) and the net synthesis of cyclin B, that seems to regulate the time required for the cdc2 kinase to reach its maximum activity. Moreover, no marked degradation of cyclin B was observed before the MI to MII transition and that which occurs does so independently of the presence of microtubules, which are essential for cyclin degradation during metaphase II arrest and exit of oocytes into interphase of the first mitotic cell cycle. Cyclin B is degraded rapidly during the transitions MI to MII, MII to the first mitotic interphase and MII to an abortive third metaphase state (MIII). However, whilst its degradation was incomplete during the MI to MII transition, virtually no cyclin B protein was detected following both the MII to interphase and MII to MIII transitions. Thus, the decision of oocytes to exit into MIII, or interphase is not controlled at the level of cyclin B degradation. Lastly, in aging, non‐activated oocytes, the net synthesis of cyclin B declines. Whereas, in activated eggs cultured in parallel although the rate of net synthesis declines initially, it is effectively ‘rescued’ being two‐fold greater than in non‐activated oocytes of an equivalent age. This gradual fall in the net synthesis of cyclin B observed in aging oocytes may contribute to the increasing ease with which they become activated, compared to recently ovulated oocytes.
The effect of epidermal growth factor and transforming growth factor β1 on proliferation and differentiation of urothelial cells in urinary bladder explant culture
Authors: Sterle Maksimiljan , Kreft Mateja Erdani , Batista Urška
Published: February 2012

The effects of two growth factors, EGF and TGFβ1, on growth and differentiation of different populations of urothelial cells in explant cultures of mouse urinary bladder have been studied by electron microscopy and lectin analysis. In an explant culture 10 days after the implantation three different populations of urothelial cells can be distinguished. Original urothelial cells, which are integral part of the explant, new urothelial cells, which cover the baso‐lateral sides of the explant and are organized in a multilayer epithelium, and new urothelial cells, which are not any more in direct contact with the explant and grow over the membrane in epithelium‐like structure. Exogenously added EGF or TGFβ1 did not affect either the formation or the thickness of multilayered urothelium, so cells were proliferating on the free surfaces of stroma as well as on the epithelium expanding over the membrane. In the absence of growth factors in medium, the newly formed baso‐lateral multilayered epithelium bordering the stroma shows ultrastructural signs of terminal differentiation suggesting that for cell proliferation and differentiation the action of stroma is of crucial importance. On the other hand, the differentiation of the epithelium spreading over the membrane, but not its thickness, is affected by exogenously added TGFβ1. Solely in TGFβ1‐treated cultures a differentiation sirnilar to that in vivo takes place. The apoptosis of the urothelial cells was not increased by TGFβ1. The lectin analysis by WGA and ConA conjugated with ferritin revealed that ConA‐ferritin combines only with the surface cells which grow over the membrane in the absence of TGFβ1.
Membrane stress causes inhibition of water channels in brush border membrane vesicles from kidney proximal tubule
Authors: Soveral Graca , Macey Robert I , Moura Teresa F
Published: February 2012

Brush border membrane vesicles (BBMV) from rabbit kidney proximal tubule cells, prepared with different internal solute concentrations (cellobiose buffer 13, 18 or 85 mosM) developed an hydrostatic pressure difference across the membrane of 18.7 mosM, that causes a membrane tension close to 5 × 10−5 N cm−1. When subjected to several hypertonic osmotic shocks an initial delay of osmotic shrinkage (a lag time), corresponding to a very small change in initial volume was apparent. This initial osmotic response, which is significantly retarded, was correlated with the initial period of elevated membrane tension, suggesting that the water permeability coefficient is inhibited by membrane stress. We speculate that this inhibition may serve to regulate cell volume in the proximal tubule.
The aquaporin‐Z water channel gene of Escherichia coli: Structure, organization and phylogeny
Authors: Calamita Giuseppe , Kempf Bettina , Rudd Kenneth E , Bonhivers Mélanie , Kneip Susanne , Bishal William R , Bremer Erhard , Agre Peter
Published: February 2012

Aquaporin water channel proteins are found throughout the plant and animal kingdoms, but the first prokaryotic water channel gene, aqpZ, was only recently identified in wild type Escherichia coli (Calamita G et al (1995) J Biol Chem 270, 29063–29066). Here we define the organization of aqpZ in E coli, produce the AqpZ protein and compare the AqpZ phylogeny to that of some known bacterial homologs. Physical mapping and sequence analyses confirmed the location of aqpZ at minute 19.7 on the E coli chromosome where it is transcribed counterclockwise. The monocistronic nature of aqpZ was clearly indicated by the structural organization of its surrounding genes, ybjD and ybjE' and by the presence of a typical Rho‐independent transcriptional terminator following the aqpZ stop codon. Computer sequence analysis indicated the −35 −10 region located 72 bases upstream of the aqpZ start codon as the most likely aqpZ promoter. A series of potential cis‐regulatory elements were found in the 400 bp region preceding the aqpZ ORF. The AqpZ protein, produced under T7Φ10 control, showed a size of about 20 kDa by SDS‐PAGE. Striking similarities were found between the E coli aqpZ and a gene included in the genome of the cyanobacterium Synechocystis sp PCC6803, a species permanently living in fresh water. These results may represent a fundamental step to characterize the regulation and the physiological features of the AqpZ water channel in prokaryotes.
Adrenalectomy does not affect the nocturnal peak of fos expression within hypothalamic pro‐opiomelanocortin neurons
Authors: Jamali Khalid A , Tramu Gérard
Published: February 2012

Circulating glucocorticoid (GC) levels are thought to modulate the basal activity of pro‐opiomelanocortin (POMC) neurons within the mediobasal hypothalamus (MBH) of the male rat. In a recent study we demonstrated that Fos‐immunoreactivity (Fos‐IR) was spontaneously induced throughout the dark phase of the light/dark cycle within a large population of these MBH neurons. Here, we have investigated the effect of adrenalectomy on the nocturnal expression of Fos protein within POMC neurons. To this aim, groups of intact (IN), adrenalectomized (ADX) and sham‐operated (sham) rats were killed 7 days after surgery (or no surgery) at times when Fos‐IR is known to show either nadir (at light offset) or peak (6 h after light offset) values within MBH POMC neurons. Brains were processed for Fos‐ and/or POMC‐immunohistochemistry. The results showed that, at both times studied, 7‐day adrenalectomy did not affect the number of POMC/Fos double‐stained neurons within the MBH. The rostro‐caudal pattern of distribution of such labeled neurons throughout the MBH of ADX rats was also similar to that of IN or sham rats. The present data demonstrate that the nocturnal induction of Fos within MBH POMC neurons is not controlled via the nychtemeral rhythm of secretion of the adrenal gland. Furthermore, this study shows that basal levels of circulating GC do not alter the nocturnal peak of Fos synthesis within POMC neurons.
Chronic melatonin treatment and the hypothalamo‐pituitary‐adrenal axis in the rat: Attenuation of the secretory response to stress and effects on hypothalamic neuropeptide content and release
Authors: Konakchieva Rossitza , Mitev Yuri , Almeida Osborne FX , Patchev Vladimir K
Published: February 2012

The pituitary‐adrenal secretory response to acute and chronic stress, suppressibility of adrenocortical secretions by exogenous glucocorticoids, and hypothalamic content and in vitro release of the two major peptidergic activators of the hypothalamo‐pituitary‐adrenal (HPA) axis, corticotropinreleasing hormone (CRH) and arginine‐vasopressin (AVP), were examined in rats receiving daily melatonin (MEL) injections coincident with the circadian increment of endogenous pineal and adrenocortical secretory activity. After 7 days of MEL administration, the rats displayed a significant attenuation of the adrenocortical secretory response to acute and chronic stress. Chronic MEL treatment also prevented the decline in adrenocorticotropic hormone (ACTH) release resulting from chronic stress exposure. Hypothalamic CRH content was significantly lower in rats receiving MEL treatment, while AVP remained largely unaltered; however, MEL administration counteracted the chronic stress‐induced decrease in hypothalamic AVP content and in vitro release. When exposed to dexamethasone in vitro, hypothalamic explants from MEL‐treated rats responded with a stronger suppression of CRH and AVP release than those originating from vehicle‐injected animals. These observations indicate that MEL attenuates the adrenocortical response to stress and influences the biosynthesis, release and glucocorticoid responsiveness of hypothalamic ACTH secretagogues.
Ultrastructural in situ hybridization: A review of technical aspects
Authors: Le Guellec Dominique
Published: February 2012

Detection of nucleic acid sequence at the ultrastructural level has allowed us to better understand the expression of genes in some fields of application in cell biology. In situ hybridization at the ultrastructural level can be carried out using three different methods: on vibratome sections before embedding in epoxy resin, on ultrathin frozen section, or on ultrathin section of tissue embedded in hydrophilic resin such as Lowicryl. Before starting the detection of nucleic acid sequences at the electron microscope level, the experimenter has to choose various parameters: the type of tissue fixation, the probe and its label, and the in situ hybridization method, depending on the sensitivity, the resolution and the ultrastructural preservation required. This review of technical aspects, by describing the different methods of ultrastructural in situ hybridization, will help the experimenter to optimize each step of the hybridization procedure.
Distribution of a centrosomal antigen during morphogenesis in the ciliated protozoan Euplotes
Authors: Fleury Anne , Lemullois Michel , Coffe Gérard
Published: February 2012

Ciliates assemble basal bodies in great number at many stages of the life‐cycle. In order to understand their assembly mechanisms, we screened a library of monoclonal antibodies directed against pericentriolar material. One of these antibodies, CTR210, was used previously to follow steps of this assembly process: in Paraurostyla, new basal bodies appear along a scaffold of linear structures recognized by this antibody. The very unusual behavior of this antigen deserved confirmation in other species. In the present study, we show by immunofluorescence that, in another phylogenetically very distant species, Euplotes, basal bodies are assembled in the same pathway during division. In addition, this antibody recognizes a filamentous ring located at the division furrow and linking many basal body assemblages. By cell fractionation and cytoskeletal extraction, we obtained fractions enriched in basal bodies and associated material. Such fractions still display a high complexity in protein composition. These fractions were used to characterize the main target of the antibody as a doublet of 45 kDa. These results confirm previous results in terms of functionality of the protein recognized by the antibody, but raise new questions in terms of the assignment of the recognized protein to the HSP70 family as hypothesized previously.
Colocalization of single ribosomes with intermediate filaments in puromycin‐treated and serum‐starved mouse embryo fibroblasts*
Authors: Traub Peter , Bauer Christoph , Hartig Roland , Grüb Sabine , Stahl Joachim
Published: February 2012

Previous experiments have revealed a relatively weak electrostatic binding capacity of in vitro reconstituted intermediate filaments (IFs) as well as of natural IFs of whole cell mount preparations for purified ribosomal particles of mammalian origin. In order to demonstrate that such associations also occur in vivo, intact cells were subjected to double immunofluorescence microscopy using antibodies directed against vimentin and ribosomal protein S17. Since in proliferating cells the majority of the ribosomal particles are assembled into polyribosomes and these are to a great extent associated with microfilaments, in vitro cultured mouse embryo skin fibroblasts (MSF cells) were treated with puromycin to allow the formation of single ribosomes. Employing confocal laser scanning microscopy, the ribosomes were detected in colocalization with vimentin IFs. Disassembly of polyribosomes was also achieved by serum starvation of cultured cells. In this case, MSF cells of a low passage attained an extended and flattened appearance with the vimentin IFs being directly associated with the cell nuclei, radiating into the peripheral areas of the cells or showing a stress fiber‐like distribution. In both cases, considerable quantities of ribosomal material were seen in close neighborhood to vimentin IFs. Frequently, these ribosome‐IF associations were coaligned with microtubules and they also surrounded myosin I‐decorated stress fibers. Double labeling with the vital, RNA‐specific fluorochrome SYTO 14 produced a fluorescence pattern largely super‐imposable on that of ribosomal protein S17. Treatment of the starved cells with either demecolcine or cytochalasin D had an only moderately disturbing effect on vimentin IF distribution and the ribosomes stayed in contact with the vimentin IFs. On the basis of these results, it is conceivable that IFs play a role in the storage of ribonucleoprotein particles in general and non‐translating ribosomes in particular in the cytoplasm of animal cells. In addition, the often seen coalignment of IFs with microtubules and microfilaments might serve facilitated and directional transport of ribonucleoprotein particles from the nucleus to peripheral areas of the cell.
Follicle‐like structure and polarized monolayer: Role of the extracellular matrix on thyroid cell organization in primary culture
Authors: Mauchamp Jean , Mirrione Aline , Alquier Christian , André Frédéric
Published: February 2012

The thyroid follicle, the morphofunctional unit of thyroid gland, is a spheroidal structure formed by a monolayer of polarized cells surrounding a closed cavity in which thyroglobulin accumulates. Newly isolated porcine thyroid cells reorganize into two types of structures which differ by the orientation of cell polarity: in follicle‐like structures, obtained in the presence of TSH, the apical pole delineates a closed cavity and cells express most parameters characteristic of thyroid function; in inside‐out follicles the apical pole is oriented towards the culture medium and cells do not express properly the thyroid function. The organization of newly formed follicles can be modified by stimulation of cell migration or by interaction of their apical poles with a new cell environment. Seeded on a hard surface (glass, plastic), cells of follicle‐like structures or inside‐out follicles formed in suspension migrate giving a monolayer. On the contrary, cells organized into a monolayer treated with hexamethylene bisacetamide, reorganize into follicle‐like structures. Inside‐out structures reoganize upon interaction of their apical poles with collagen I gel, a coherent matrix, or with a reconstituted basement membrane (RBM), a soft matrix. Overlaid with collagen I, monolayers reorganize into follicles. Embedded in collagen I or in RBM, inside‐out follicles reorient their polarity giving functional follicles. On the RBM surface, cells pull on the gel and embed themselves in the soft matrix gel, finally reorienting their polarity to inside‐in polarity. When comparing thyroid cells with other epithelial cell types (mammary cells, Sertoli cells), it appears that the obtention in culture of follicle‐like structures, ie closed inside‐in polarized cell organization, is the best way to express in culture both morphology and function of any specific epithelial tissue, the polarized monolayer in porous bottom culture chamber coming just behind.
A novel macrophage receptor enhances MHC II‐peptide leading and surface expression of a hapten‐protein conjugate
Authors: Weaver Donald J , Voss Edward W
Published: February 2012

A receptor possessing specificity for fluorescein was previously identified on murine macrophage. The goal of the present study was to determine if this receptor influenced MHC II‐peptide loading and surface expression of a hapten‐protein conjugate within murine macrophage. Although inhibition of fluid‐phase pinocytosis had no detectable effect, lower levels of intracellular MHC II‐peptide complexes were observed upon inhibition of receptor‐mediated endocytosis. Moreover, lower levels of surface expressed MHC II‐fluoresceinated peptide complexes were also detected. Following subcellular fractionation experiments, it was revealed that the receptor altered the endocytic trafficking of the antigen within the cell. Namely, degraded antigen and MHC II‐peptide complexes were not observed in dense transferrin receptor positive, cathepsin D positive, LAMP‐1 positive organelles upon inhibition of the receptor. Previous studies also suggested that this receptor enhanced MHC II‐peptide loading by concentrating high levels of antigen to endocytic organelles. The implications of these findings on subsequent development of the immune response were also discussed.
Cytoplasmic control of nuclear behavior during meiotic maturation of frog oocytes*
Authors: Duesbery Nicholas S. Vande , Woude George F. Vande
Published: February 2012

The title of this article is taken from a 1971 publication by Yoshio Masui and Clement Markert in which they describe the discoveries of the meiotic regulatory activities maturation promoting factor and cytostatic factor. Here we review the experiments that led to these discoveries and discuss their relation to our current knowledge of the biochemistry of oocyte maturation.
Overexpression of the cytoplasmic retention signal region of cyclin B2, but not of cyclin B1, inhibits bipolar spindle formation in Xenopus oocytes
Authors: Yoshitome Satoshi , Furuno Nobuaki , Sagata Noriyuki
Published: February 2012

Cyclin B, a regulatory subunit of maturation/M‐phase promoting factor (MPF), has several subtypes in many vertebrate species. However, it is not known whether the different B‐type cyclins have any different functions in vertebrate cells, although their subcellular localizations seem to differ largely from each other. To examine the roles of two major B‐type cyclins, B1 and B2, in spindle formation in M phase, we overexpressed their N‐termini in Xenopus oocytes; the N‐termini of cyclins B1 and B2 contained a cytoplasmic retention signal (CRS), and hence their overexpressions were expected to competitively inhibit the subcellular localizations of the endogenous cyclins B1 and B2, respectively. Upon entry into meiosis I, oocytes overexpressing the cyclin B1 N‐terminus formed an apparently normal bipolar spindle, but those oocytes overexpressing the cyclin B1 N‐terminus formed a monopolar (or monoastral) spindle. This defect in bipolar spindle formation was observed only when the cyclin B2 N‐terminus contained its own CRS sequence, and was able to be rescued by overexpression of full‐length cyclin B2. These results suggest, for the first time, that the correct subcellular localization of cyclin B2, but not of cyclin B1, is essential for (the initiation of) bipolar spindle formation in Xenopus oocytes.
An indirect role for cyclin B‐Cdc2 in inducing chromosome condensation in Xenopus egg extracts*
Authors: Shimada Arata , Ohsumi Keita , Kishimoto Takeo
Published: February 2012

We have studied the cytoplasmic mechanism that induces metaphase chromosome condensation in cell‐free Xenopus egg extracts. To analyze the mechanism responsible for inducing chromosome condensation separately from those responsible for sperm chromatin remodeling and nuclear envelope disassembly, we used Xenopus sperm chromatin that had already been remodeled to nucleosomal chromatin by incubating demembranated sperm with egg extracts added with lysolecithin. We found that inhibition of cyclin B‐Cdc2 with butyrolactone I abolished chromosome condensation of the remodeled sperm chromatin by M‐phase egg extracts, but incubation of the chromatin with active cyclin B‐Cdc2 alone did not induce chromosome condensation, indicating a requirement for cytoplasmic factor(s) in addition to cyclin B‐Cdc2 for the induction of chromosome condensation. We further demonstrated that if the cyclin B‐Cdc2‐dependent phosphorylation state was protected against dephosphorylation by a preincubation of M‐phase extracts with ATP‐γ‐S, chromosome condensation and phosphorylation of chromosomal histone H1 occurred even when extracts were depleted of cyclin B‐Cdc2 activity. The chromosome condensation seen in the absence of cyclin B‐Cdc2 was completely inhibited with another protein kinase inhibitor, 6‐dimethylaminopurine, implying that a protein kinase other than cyclin B‐Cdc2 was involved in the induction of chromosome condensation. These results strongly suggest that a cyclin B‐Cdc2‐dependent protein kinase cascade is involved in inducing chromosome condensation and the phosphorylation of chromosomal histone H1.
Cell cycle transition in early embryonic development of Xenopus laevis
Authors: Masui Yoshio , Wang Ping
Published: February 2012

This article reviews cell cycle changes that occur during midblastula transition (MBT) in Xenopus laevis based on research carried out in the authors' laboratory. Blastomeres dissociated from the animal cap of blastulae, as well as those in an intact embryo, divide synchronously with a constant cell cycle duration in vitro, up to the 12th cell cycle regardless of their cell sizes. During this synchronous cleavage, cell sizes of blastomeres become variable because of repeated unequal cleavage. After the 12th cell cycle blastomeres require contact with an appropriate protein substrate to continue cell division. When nucleocytoplasmic (N/C) ratios of blastomeres reach a critical value during the 13th cycle, their cell cycle durations lengthen in proportion to the reciprocal of cell surface areas, and cell divisions become asynchronous due to variations in cell sizes. The same changes occur in haploid blastomeres with a delay of one cell cycle. Thus, post‐MBT cell cycle control becomes dependent not only on the N/C relation but also on cell surface activities of blastomeres. Unlike cell cycle durations of pre‐MBT blastomeres, which show monomodal frequency distributions with a peak at about 30 min, those of post‐MBT blastomeres show polymodal frequency distributions with peaks at multiples of about 30 min, suggesting ‘quantisement’ of the cell cycle. Thus, we hypothesised that MPF is produced periodically during its unit cycle with 30 min period, but it titrates, and is neutralized by, an inhibitor contained in the nucleus in a quantity proportional to the genome size; however, when all of the inhibitor has been titrated, excess MPF during the last cycle triggers mitosis. At MBT, cell cycle checkpoint mechanisms begin to operate. While the operation of S phase checkpoint to monitor DNA replication is initiated by N/C relation, the initiation of M phase checkpoint operation to monitor chromosome segregation at mitosis is regulated by an age‐dependent mechanism.
Rescue of K562 cells from MDM2‐modulated p53‐dependent apoptosis by growth factor‐induced differentiation
Authors: Mahdi Tarek , Alcalay Dominique , Cognard Christian , Tanzer Joseph , Kitzis Alain
Published: February 2012

The wild‐type human MDM2 protooncogene was tested for its ability to modulate apoptotic activity of the de novo expressed p53 tumor suppressor gene in K562 cells. We also studied the role ofsome cytokines in this phenomenon. K562, a human myeloid leukemia cell line, does not express p53 at the mRNA or protein level. In this study, we stably transfected K562 with eukaryotic vectors containing either normal p53 cDNA (pC53‐SN3) or mutated p53 (143Val→Ala) cDNA (pC53‐SCX3). Transfectants expressing WT p53 or those expressing mutant p53 are called K562 SN and K562 SM respectively. Many leukemic cell lines undergo apoptosis when de novo WT p53 is expressed alone. In contrast, while the resulting clones (K562 SN and K562 SM) expressed p53, they did not undergo apoptosis. However, when treated with MDM2 mRNA antisense (MDM2 AS) oligodeoxynucleotides (ODNs), K562 SN demonstrated apoptotic features at both molecular and morphological levels. No change was observed when the other clones (K562 and K562 SM) were treated with MDM2 AS. Apoptosis induced in this manner was associated with a relatively small increase in intracellular calcium [Ca2+]i. Cells cultured in medium previously supplemented with recombinant human (rh) interleukin (IL)‐3 and rh‐erythropoietin (Epo) did not undergo apoptosis. Moreover, K562 SN cells were induced to differentiate. This differentiation was evaluated by measuring hemoglobin (Hb) level in cellular extracted proteins and by analyzing erythroid colony number and morphology. High Hb synthesis was obtained when K562 SN cells were cultured with cytokines (IL‐3 + Epo) combined with MDM2 AS. Our results are consistent with the hypothesis that the function of the proto‐oncogene MDM2 is to provide a ‘feedback’ mechanism for the p53‐dependent pathway of apoptosis that could be shunted toward differentiation.
The pineal organ as a folded retina: Immunocytochemical localization of opsins*
Authors: Vígh Béla , Röhlich Pál , Görcs Tamás , Silva Maria João Manzano e , Szél ágoston , Fejér Zsolt , Vígh‐Teichmann Ingeborg
Published: February 2012

The most simple pineal complex (the pineal and parapineal organs of lampreys), consists of saccular evaginations of the diencephalic roof, and has a retina‐like structure containing photoreceptor cells and secondary neurons. In more differentiated vertebrates, the successive folding of the pineal wall multiplies the cells and reduces the lumen of the organ, but the pattern of the histological organization remains similar to that of lampreys; therefore, we consider the histological structure of the pineal organ of higher vertebrates as a ‘folded retina’. The cell membrane of several pineal photoreceptor outer‐segments of vertebrates immunoreact with anti‐retinal opsin antibodies supporting the view of retina‐like organization of the pineal. Some other pineal outer segments do not react with retinal anti‐opsin antibodies, a result suggesting the presence of special pineal photopigments in different types of pinealocytes that obviously developed during evolution. The chicken pinopsin, detected in the last years, may represent one of these unknown photopigments. Using antibodies against chicken pinopsin, we compared the immunoreactivity of different photoreceptors of the pineal organs from cyclostomes to birds at the light and electron microscopic levels. We found pinopsin immunoreaction on all pinealocytes of birds and on the rhodopsin‐negative large reptilian pinealocytes. As the pinopsin has an absorption maximum at 470 nm, these avian and reptilian immunoreactive pinealocytes can be regarded as green‐blue light‐sensitive photoreceptors. Only a weak immunoreaction was observed on the frog and fish pinealocytes and no reaction was seen in cyclostomes and in the frontal organ of reptiles. Some photoreceptors of the retina of various species also reacted the pinopsin antibodies, therefore, pinopsin must have certain sequential similarity to individual retinal opsins of some vertebrates.
Impairment of cell division in tolA mutants of Escherichia coli at low and high medium osmolarities
Authors: Meury Jean , Devilliers Ginette
Published: February 2012

Mutations in the tolA gene of Escherichia coli cause the cell to become sensitive to detergents and to some antibiotics, to release periplasmic enzymes and to be resistant to group A colicins; tolA mutations also lead to mucoid phenotype. TolA is a three‐domain protein anchored in the inner membrane by its N‐terminal domain. The second domain is proposed to span the periplasmic space and to interact with trimeric porins of the outer membrane. TolA proteins are considered to be located in the adhesion zones between inner and outer membranes. Our observations by confocal and electron microscopy have revealed that tolA mutants show modified morphology and produce DNA‐free cells. Increasing or decreasing medium osmolarity amplifies these defects; mutants become essentially unable to locate the division site properly so that cells of highly unequal lengths are produced. Moreover, septation is impaired with asymmetric constrictions and oblique septa. These results suggest that TolA could play a role in positioning the division sites via the organisation of either the outer membrane or the possible adhesion zones.
Centrosome structure and microbubule nucleation in animal cells
Authors: Tassin Anne‐Marie , Bornens Michel
Published: February 2012

Genetic studies in the budding yeast have led to the molecular characterization of γ‐tubulin associated proteins and to the identification of orthologues in animal cells. While the γ‐tubulin complex is more complex in animal cells than in budding yeast, its function is probably maintained throughout evolution. In this review we discuss some of the possible regulations of the nucleation activity in the light of the centrosome structure. A potential cross‐talk between microtubule nucleation and centrosome duplication is suggested by some, still scarce, data.
Centrosome inheritance in insects: Fertilization and parthenogenesis
Authors: Callaini Giuliano , Riparbelli Maria Giovanna , Dallai Romano
Published: February 2012

Centrosome biogenesis is unclear, although much structural and biochemical research has been performed in several experimental systems. An alternative model to study the assembly of functional centrosomes could be the process of zygotic centrosome formation at the beginning of embryonic development. Although it seems obvious that the sperm cell provides the centrosome at fertilization, some pieces of evidence are not in line with this point of view and give controversial results. Such an analysis could provide useful information if applied to a large variety of organisms. Since insects are a highly diverse group of organisms they provide a variety of models in which to study the process of centrosome reconstitution during fertilization. Moreover, many insect species reproduce by parthenogenesis, a special mode of reproduction in which embryonic development occurs without male contribution. Studies of unfertilized parthenogenetic eggs may therefore teach us much about the process of centrosome assembly in the absence of preexisting centrioles.
Condensation‐decondensation of the γ‐tubulin containing material in the absence of a structurally visible organelle during the cell cycle of Physarum plasmodia
Authors: Rotaru Victor , Lajoie‐Mazenc Isabelle , Tollon Yvette , Raynaud‐Messina Brigitte , Jean Catherine , Détraves Claire , Julian Monique , Moisand André , Wright Michel
Published: February 2012

Genetic evidence has shown the presence of a common spindle pole organiser in Physarum amoebae and plasmodia. But the typical centrosome and mitosis observed in amoebae are replaced in plasmodia by an intranuclear mitosis devoid of any structurally defined organelle. The fate of γ‐tubulin and of another component (TPH17) of the centrosome of Physarum amoebae was investigated in the nuclei of synchronous plasmodia. These two amoebal centrosomal elements were present in the nuclear compartment during the entire cell cycle and exhibited similar relocalisation from metaphase to telophase. Three preparation methods showed that γ‐tubulin containing material was dispersed in the nucleoplasm during interphase. It constituted an intranuclear thread‐like structure. In contrast, the TPH17 epitope exhibited a localisation close to the nucleolus. In late G2‐phase, the γ‐tubulin containing elements condensed in a single organelle which further divided. Intranuclear microtubules appeared before the condensation of the γ‐tubulin material and treatment with microtubule poisons suggested that microtubules were required in this process. The TPH17 epitope relocalised in the intranuclear spindle later than the γ‐tubulin containing material suggesting a maturation process of the mitotic poles. The decondensation of the γ‐tubulin material and of the material containing the TPH17 epitope occurred immediately after telophase. Hence in the absence of a structurally defined centrosome homologue, the microtubule nucleating material undergoes a cycle of condensation and decondensation during the cell cycle.
Centrosomes and cancer
Authors: Salisbury Jeffrey L , Whitehead Clark M , Lingle Wilma L , Barrett Susan L
Published: February 2012

The centrosome functions as the major microtubule organizing center (MTOC) of the cell and as such it determines the number, polarity, and organization of interphase and mitotic microtubules. Cytoplasmic organization, cell polarity and the equal partition of chromosomes into daughter cells at the time of cell division are all dependent on the normal function of the centrosome and on its orderly duplication, once and only once, in each cell cycle. Malignant tumor cells show characteristic defects in cell and tissue architecture and in chromosome number that can be attributed to inappropriate centrosome behavior during tumor progression. In this review, we will summarize recent observations linking centrosome defects to disruption of normal cell and tissue organization and to chromosomal instability found in malignant tumors.
The Xenopus laevis centrosome aurora/lpl1‐related kinase
Authors: Giet Régis , Uzbekov Rustem , Kireev Igor , Prigent Claude
Published: February 2012

The cDNA encoding the protein kinase pEg2 was originally cloned through a differential screening performed during the early development of Xenopus laevis. pEg2 orthologues were found in various organisms and were classified in a new family of oncogenic mitotic protein kinases named ‘aurora/Ipl1‐related kinases’ after the Drosophila melanogaster gene aurora and the Saccharomyces cerevisiae gene Ipl1. The catalytic activity of pEg2 is necessary for the mitotic microtubule spindle formation in Xenopus laevis egg extracts. The addition of a dominant negative form of pEg2 to in vitro spindle assembly assays leads to monopolar spindles generated by a defect of centrosome separation. In Xenopus cultured cells, pEg2 was confined around the pericentriolar material once centrosomes were duplicated. The centrosome localization does not depend on the presence of microtubules. However, in vitro, the protein binds to taxol‐stabilized microtubules independently of its kinase activity. During mitosis the location of the protein changes, in metaphase the kinase localizes on the microtubules at the poles of the mitotic spindle whereas it is not present on astral microtubules. This localization persists until the segregation of the chromosomes is completed. The presence of the kinase on the spindle may reveal another yet unknown function.
ADAMTS13 activity may predict the cumulative survival of patients with liver cirrhosis in comparison with the Child‐Turcotte‐Pugh score and the Model for End‐Stage Liver Disease score
Authors: Takaya Hiroaki , Uemura Masahito , Fujimura Yoshihiro , Matsumoto Masanori , Matsuyama Tomomi , Kato Seiji , Morioka Chie , Ishizashi Hiromichi , Hori Yuji , Fujimoto Masao , Tsujimoto Tatsuhiro , Kawaratani Hideto , Toyohara Masahisa , Kurumatani Norio , Fukui Hiroshi
Published: February 2012

Aim:  Decreased plasma ADAMTS13 activity (ADAMTS13:AC) results in accumulation of unusually large von Willebrand factor multimers and platelet thrombi formation. Our aim was to evaluate whether ADAMTS13:AC is a prognostic marker in patients with liver cirrhosis.

Methods:  Plasma ADAMTS13:AC and its related parameters were examined in 108 cirrhotic patients.

Results:  ADAMTS13:AC decreased as the severity of liver disease increased (means: controls 100%, Child A‐cirrhotics 79%, Child B‐cirrhotics 63%, and Child C‐cirrhotics 31%). ADAMTS13:AC markedly decreased in the cirrhotics with hepatorenal syndrome, refractory ascites and hepatic encephalopathy. The cumulative survival time was the shortest (median: 4.5 months) in the cirrhotics with severe to moderate ADAMTS13:AC deficiency (<3–25%), followed by those with mild ADAMTS13:AC deficiency (25–50%), and was the longest in those with normal activity (>50%). In contrast, based on the Child‐Turcotte‐Pugh (CTP) score, Child C‐cirrhotics had the worst survival, but the survival probabilities did not differ between Child A and B cirrhotics. Based on the Model for End‐Stage Liver Disease (MELD) score, the survival was the worst for the cirrhotics in the fourth quartile, but it was not different among cirrhotics in the first three quartiles. Cox proportional‐hazards regression analysis showed that ADAMTS13:AC and serum albumin were independent factors affecting the survival.

Conclusions:  ADAMTS13:AC concomitantly decreases as the functional liver capacity decreases. This activity may be a useful prognostic marker that is equal or superior to the CTP score and the MELD score to predict not only the short‐term prognosis but also the long‐term survival of the cirrhotic patients.
The Effects of Representations, Constructivist Approaches, and Engagement on Middle School Students' Algebraic Procedure and Conceptual Understanding
Authors: Ross Amanda , Willson Victor
Published: February 2012

This study examined the effects of types of representations, constructivist teaching approaches, and student engagement on middle school algebra students' procedural knowledge and conceptual understanding. Data gathered from 16 video lessons and algebra pretest/posttests were used to run three multilevel structural equation models. Symbolic representations (p < .02), shared meanings (p < .05), and meaningful feedback (p < .10) significantly increased procedural and conceptual understanding. Enactive representations significantly increased procedural knowledge (p < .05). There was also a significant relationship between the two types of learning at the within level (p < .01) and between level (p < .05).