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Reminiscent
Kinds of Reminiscent Selected AbstractsCharacterization of ,-synuclein aggregation and synergistic toxicity with protein tau in yeastFEBS JOURNAL, Issue 6 2005Piotr Zabrocki A yeast model was generated to study the mechanisms and phenotypical repercussions of expression of ,-synuclein as well as the coexpression of protein tau. The data show that aggregation of ,-synuclein is a nucleation,elongation process initiated at the plasma membrane. Aggregation is consistently enhanced by dimethyl sulfoxide, which is known to increase the level of phospholipids and membranes in yeast cells. Aggregation of ,-synuclein was also triggered by treatment of the yeast cells with ferrous ions, which are known to increase oxidative stress. In addition, data are presented in support of the hypothesis that degradation of ,-synuclein occurs via autophagy and proteasomes and that aggregation of ,-synuclein disturbs endocytosis. Reminiscent of observations in double-transgenic mice, coexpression of ,-synuclein and protein tau in yeast cells is synergistically toxic, as exemplified by inhibition of proliferation. Taken together, the data show that these yeast models recapitulate major aspects of ,-synuclein aggregation and cytotoxicity, and offer great potential for defining the underlying mechanisms of toxicity and synergistic actions of ,-synuclein and protein tau. [source] Embryonic transcription factors in human breast cancerIUBMB LIFE, Issue 3 2006Karoline J. Briegel Abstract Growing evidence suggests that breast cancer cells often reactivate latent developmental programs in order to efficiently execute the multi-step process of tumorigenesis. This review focuses on key transcriptional regulators of embryonic development that are deregulated in breast cancer and discusses the molecular mechanisms by which these proteins control carcinogenesis. Reminiscent of their function during development, embryonic transcription factors regulate changes in gene expression that promote tumor cell growth, cell survival and motility, as well as a morphogenetic process called epithelial-mesenchymal transition (EMT), which is implicated in both breast metastasis and tumor recurrence. Because of their pivotal roles in breast tumor progression, these factors represent valuable new biomarkers for breast cancer detection as well as promising new targets for anti-invasive drugs. IUBMB Life, 58: 123-132, 2006 [source] Role of the two type II myosins, Myo2 and Myp2, in cytokinetic actomyosin ring formation and function in fission yeastCYTOSKELETON, Issue 3 2003Daniel P. Mulvihill Abstract The formation and contraction of a cytokinetic actomyosin ring (CAR) is essential for the execution of cytokinesis in fission yeast. Unlike most organisms in which its composition has been investigated, the fission yeast CAR contains two type II myosins encoded by the genes myo2+ and myp2+. myo2+ is an essential gene whilst myp2+ is dispensable under normal growth conditions. Myo2 is hence the major contractile protein of the CAR whilst Myp2 plays a more subtle and, as yet, incompletely documented role. Using a fission yeast strain in which the chromosomal copy of the myo2+ gene is fused to the gene encoding green fluorescent protein (GFP), we analysed CAR formation and function in the presence and absence of Myp2. No change in the rate of CAR contraction was observed when Myp2 was absent although the CAR persisted longer in the contracted state and was occasionally observed to split into two discrete rings. This was also observed in myp2, cells following actin depolymerisation with latrunculin. CAR contraction in the absence of Myp2 was completely abolished in the presence of elevated levels of chloride ions. Thus, Myp2 appears to contribute to the stability of the CAR, in particular at a late stage of CAR contraction, and to be a component of the signalling pathway that regulates cytokinesis in response to elevated levels of chloride. To determine whether the presence of two type II myosins was a feature of cytokinesis in other fungi that divide by septation, we searched the genomes of two filamentous fungi, Aspergillus fumigatus and Neurospora crassa, for myosin genes. As in fission yeast, both A. fumigatus and N. crassa contained myosins of classes I, II, and V. Unlike fission yeast, both contained a single type II myosin gene that, on the basis of its tail structure, was more reminiscent of Myp2 than Myo2. The significance of these observations to our understanding of septum to formation and cleavage is discussed. Cell Motil. Cytoskeleton 54:208,216, 2003. © 2003 Wiley-Liss, Inc. [source] Novel markers of early ovarian pre-granulosa cells are expressed in an Sry -like patternDEVELOPMENTAL DYNAMICS, Issue 4 2009Hyunjoo J. Lee Abstract Mammalian gonad differentiation involves sexually dimorphic cell-fate decisions within the bipotential gonadal primordia. Testis differentiation is initiated by a center-to-poles wave of Sry expression that induces supporting cell precursors (SCPs) to become Sertoli rather than granulosa cells. The initiation of ovary differentiation is less well understood. We identified two novel SCP markers, 1700106J16Rik and Sprr2d, whose expression is ovary-biased during early gonad development, and altered in Wnt4, Sf1, Wt1, and Fog2 mutant gonads. In XX and XY gonads, both genes were up-regulated at ,E11 in a center-to-poles wave, and then rapidly down-regulated in XY gonads in a center-to-poles wave, which is reminiscent of Sry expression in XY gonads. Our data suggest that 1700106J16Rik and Sprr2d may have important roles in early gonad development, and are consistent with the hypothesis that ovarian SCP differentiation occurs in a center-to-poles wave with similar timing to that of testicular SCP differentiation. Developmental Dynamics 238:812,825, 2009. © 2009 Wiley-Liss, Inc. [source] Comparative genomic and expression analysis of group B1 sox genes in zebrafish indicates their diversification during vertebrate evolutionDEVELOPMENTAL DYNAMICS, Issue 3 2006Yuich Okuda Abstract Group B1 Sox genes encode HMG domain transcription factors that play major roles in neural development. We have identified six zebrafish B1 sox genes, which include pan-vertebrate sox1a/b, sox2, and sox3, and also fish-specific sox19a/b. SOX19A/B proteins show a transcriptional activation potential that is similar to other B1 SOX proteins. The expression of sox19a and sox3 begins at approximately the 1,000-cell stage during embryogenesis and becomes confined to the future ectoderm by the shield stage. This is reminiscent of the epiblastic expression of Sox2 and/or Sox3 in amniotes. As development progresses, these six B1 sox genes display unique expression patterns that overlap distinctly from one region to another. sox19a expression is widespread in the early neuroectoderm, resembling pan-neural Sox2 expression in amniotes, whereas zebrafish sox2 shows anterior-restricted expression. Comparative genomics suggests that sox19a/b and mammalian Sox15 (group G) have an orthologous relationship and that the B1/G Sox genes arose from a common ancestral gene through two rounds of genome duplication. It seems likely, therefore, that each B1/G Sox gene has gained a distinct expression profile and function during vertebrate evolution. Developmental Dynamics 235:811,825, 2006. © 2006 Wiley-Liss, Inc. [source] Gli3 null mice display glandular overgrowth of the developing stomachDEVELOPMENTAL DYNAMICS, Issue 4 2005Jae H. Kim Abstract The role of the Hedgehog signaling pathway in various aspects of gut development is still poorly understood. In the developing stomach, Sonic (Shh) and Indian (Ihh) hedgehog are expressed in both distinct and overlapping regions. Loss of Sonic hedgehog function in the stomach results in a glandular phenotype of intestinal transformation and overgrowth. These changes are reminiscent of the pre-malignant lesion, intestinal metaplasia. To determine the role of Hedgehog-related transcription factors, Gli2 and Gli3, in Shh signaling during stomach development, we conducted a mutant analysis of glandular stomach from Shh, Gli2, and Gli3 mutant mice. Although Gli2 principally mediates the activator function of Shh, surprisingly we observed minimal changes in glandular development in the Gli2 mutant stomach. Furthermore, Gli3, which typically functions as a repressor of Hedgehog signal, showed a striking phenocopy of the glandular expansion and intestinal transformation found in Shh mutant stomach. A reduction in apoptotic events was seen in all mutant stomachs with no appreciable changes in proliferation. Both Shh and Gli3 mutant stomachs displayed early changes of intestinal transformation but these did not impact on the overall differentiation of the gastric epithelium. Interestingly, the observation that Gli3 shares a similar glandular phenotype to Shh mutant stomach reveals a possible novel role of Gli3 activator in the developing stomach. The embryonic stomach is a unique model of the Hedgehog pathway function and one that may help to uncover some of the mechanisms underlying the development of intestinal metaplasia. Developmental Dynamics 234:984,991, 2005. © 2005 Wiley-Liss, Inc. [source] Intracerebral large artery disease in Aicardi,Goutičres syndrome implicates SAMHD1 in vascular homeostasisDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 8 2010VENKATESWARAN RAMESH Aim, To describe a spectrum of intracerebral large artery disease in Aicardi,Goutičres syndrome (AGS) associated with mutations in the AGS5 gene SAMHD1. Method, We used clinical and radiological description and molecular analysis. Results, Five individuals (three males, two females) were identified as having biallelic mutations in SAMHD1 and a cerebral arteriopathy in association with peripheral vessel involvement resulting in chilblains and ischaemic ulceration. The cerebral vasculopathy was primarily occlusive in three patients (with terminal carotid occlusion and basal collaterals reminiscent of moyamoya syndrome) and aneurysmal in two. Three of the five patients experienced intracerebral haemorrhage, which was fatal in two individuals. Post-mortem examination of one patient suggested that the arteriopathy was inflammatory in origin. Interpretation, Mutations in SAMHD1 are associated with a cerebral vasculopathy which is likely to have an inflammatory aetiology. A similar disease has not been observed in patients with mutations in AGS1 to AGS4, suggesting a particular role for SAMHD1 in vascular homeostasis. Our report raises important questions about the management of patients with mutations in SAMHD1. [source] The molecular receptive range of an olfactory receptor in vivo (Drosophila melanogaster Or22a)DEVELOPMENTAL NEUROBIOLOGY, Issue 14 2006Daniela Pelz Abstract Understanding how odors are coded within an olfactory system requires knowledge about its input. This is constituted by the molecular receptive ranges (MRR) of olfactory sensory neurons that converge in the glomeruli of the olfactory bulb (vertebrates) or the antennal lobe (AL, insects). Aiming at a comprehensive characterization of MRRs in Drosophila melanogaster we measured odor-evoked calcium responses in olfactory sensory neurons that express the olfactory receptor Or22a. We used an automated stimulus application system to screen [Ca2+] responses to 104 odors both in the antenna (sensory transduction) and in the AL (neuronal transmission). At 10,2 (vol/vol) dilution, 39 odors elicited at least a half-maximal response. For these odorants we established dose-response relationships over their entire dynamic range. We tested 15 additional chemicals that are structurally related to the most efficient odors. Ethyl hexanoate and methyl hexanoate were the best stimuli, eliciting consistent responses at dilutions as low as 10,9. Two substances led to calcium decrease, suggesting that Or22a might be constitutively active, and that these substances might act as inverse agonists, reminiscent of G-protein coupled receptors. There was no difference between the antennal and the AL MRR. Furthermore we show that Or22a has a broad yet selective MRR, and must be functionally described both as a specialist and a generalist. Both these descriptions are ecologically relevant. Given that adult Drosophila use approximately 43 ORs, a complete description of all MRRs appears now in reach. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Pre-/post-otic rhombomeric interactions control the emergence of a fetal-like respiratory rhythm in the mouse embryoDEVELOPMENTAL NEUROBIOLOGY, Issue 12 2006C. Borday Abstract How regional patterning of the neural tube in vertebrate embryos may influence the emergence and the function of neural networks remains elusive. We have begun to address this issue in the embryonic mouse hindbrain by studying rhythmogenic properties of different neural tube segments. We have isolated pre- and post-otic hindbrain segments and spinal segments of the mouse neural tube, when they form at embryonic day (E) 9, and grafted them into the same positions in stage-matched chick hosts. Three days after grafting, in vitro recordings of the activity in the cranial nerves exiting the grafts indicate that a high frequency (HF) rhythm (order: 10 bursts/min) is generated in post-otic segments while more anterior pre-otic and more posterior spinal territories generate a low frequency (LF) rhythm (order: 1 burst/min). Comparison with homo-specific grafting of corresponding chick segments points to conservation in mouse and chick of the link between the patterning of activities and the axial origin of the hindbrain segment. This HF rhythm is reminiscent of the respiratory rhythm known to appear at E15 in mice. We also report on pre-/post-otic interactions. The pre-otic rhombomere 5 prevents the emergence of the HF rhythm at E12. Although the nature of the interaction with r5 remains obscure, we propose that ontogeny of fetal-like respiratory circuits relies on: (i) a selective developmental program enforcing HF rhythm generation, already set at E9 in post-otic segments, and (ii) trans-segmental interactions with pre-otic territories that may control the time when this rhythm appears. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Maladaptation to mental stress mitigated by the adaptive immune system via depletion of naturally occurring regulatory CD4+CD25+ cellsDEVELOPMENTAL NEUROBIOLOGY, Issue 6 2006Hagit Cohen Abstract Peripheral cellular immunity was recently shown to play a critical role in brain plasticity and performance. The antigenic specificity of the participating T cells, however, was not investigated, and nor was their relevance to psychological stress. Here we show, using a mouse model, that adaptive immunity mitigates maladaptation to the acute psychological stress known to trigger abnormal behaviors reminiscent of human post-traumatic stress disorder. Assessment of behavioral adaptation (measured by the acoustic startle response and avoidance behavior) in mice after their exposure to predator odor revealed that maladaptation was several times more prevalent in T cell-deficient mice than in their wild-type counterparts. A single population of T cells reactive to central nervous system (CNS)-associated self-protein was sufficient to endow immune-deficient mice with the ability to withstand the psychological stress. Naturally occurring CD4+CD25+ regulatory T cells were found to suppress this endogenous anti-stress attribute. These findings suggest that T cells specific to abundantly expressed CNS antigens are responsible for brain tissue homeostasis and help the individual to cope with stressful life episodes. They might also point the way to development of immune-based therapies for mental disorders, based either on up-regulation of T cells that partially cross-react with self-antigens or on weakening of the activity of regulatory T cells. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Nicotinic synapses formed between chick ciliary ganglion neurons in culture resemble those present on the neurons in vivoDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2001Min Chen Abstract We studied nicotinic synapses between chick ciliary ganglion neurons in culture to learn more about factors influencing their formation and receptor subtype dependence. After 4,8 days in culture, nearly all neurons displayed spontaneous excitatory postsynaptic currents (sEPSCs), which occurred at about 1 Hz. Neurons treated with tetrodotoxin displayed miniature EPSCs (mEPSCs), but these occurred at low frequency (0.1 Hz), indicating that most sEPSCs are actually impulse driven. The sEPSCs could be classified by decay kinetics as fast, slow, or biexponential and, reminiscent of the situation in vivo, were mediated by two major nicotinic acetylcholine receptor (AChR) subtypes. Fast sEPSCs were blocked by ,-bungarotoxin (,Bgt), indicating dependence on ,Bgt-AChRs, most of which are ,7 subunit homopentamers. Slow sEPSCs were unaffected by ,Bgt, and were blocked instead by the ,3/,2-selective ,-conotoxin-MII (,CTx-MII), indicating dependence on ,3*-AChRs, which lack ,7 and contain ,3 subunits. Biexponential sEPSCs were mediated by both ,Bgt- and ,3*-AChRs because they had fast and slow components qualitatively similar to those comprising simple events, and these were reduced by ,Bgt and blocked by ,CTx-MII, respectively. Fluorescence labeling experiments revealed both ,Bgt- and ,3*-AChR clusters on neuron somata and neurites. Colabeling with antisynaptic vesicle protein antibody suggested that some ,3*-AChR clusters, and a few ,Bgt-AChR clusters are associated with synaptic sites, as is the case in vivo. These findings demonstrate the utility of ciliary ganglion neuron cultures for studying the regulation of nicotinic synapses, and suggest that mixed AChR subtype synapses characteristic of the neurons in vivo can form in the absence of normal inputs or targets. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 265,279, 2001 [source] Cytology of metastatic cervical squamous cell carcinoma in pleural fluid: Report of a case confirmed by human papillomavirus typingDIAGNOSTIC CYTOPATHOLOGY, Issue 5 2009Roberto G. Gamez M.D. Abstract Cervical squamous cell carcinomas are rarely the cause of malignant effusions. Their identification can be relatively easy when keratinizing atypical squamous cells are present, but may be very difficult when only nonkeratinizing malignant cells are present. We present the case of a 47-year-old woman who presented with a large left pleural effusion after having recently completed chemoradiation therapy for stage IIB cervical squamous cell carcinoma. Cytologic examination of the fluid showed a uniform population of single atypical cells with finely vacuolated cytoplasm, ectoendoplasmic demarcation, cell-in-cell arrangements, and short rows of cells with intervening "windows," all features reminiscent of mesothelial cells. No keratinization or three-dimensional cell clusters were identified. A panel of immunohistochemical stains was performed on the cell block material, and the atypical cells were positive for cytokeratin 5/6, p63, and p16 but not for cytokeratin 7, calretinin, WT1, or Ber-EP4 or TTF1. These findings were consistent with metastatic squamous cell carcinoma. HPV DNA determination and typing by PCR confirmed the presence of HPV16 in an aliquot of pleural fluid. This is to our knowledge the first reported case of pleural fluid involved by metastatic squamous cell carcinoma where HPV DNA testing was used to confirm the origin of the metastasis. Despite its rarity, metastatic nonkeratinizing squamous cell carcinoma should be considered when a single cell population of large atypical cells is found in effusions. Immunoperoxidase stains and HPV testing can be performed to establish the diagnosis and confirm the origin from a cervical primary. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source] Endoscopic ultrasound-guided fine needle aspiration diagnosis of metastatic sex cord tumor with annular tubules: A case reportDIAGNOSTIC CYTOPATHOLOGY, Issue 8 2006Lori J. Ryan M.D. Abstract The cytologic findings of a paratracheal metastasis from a malignant sex cord tumor with annular tubules (SCTATs) diagnosed by endoscopic ultrasound guided fine needle aspiration are described. Cytologic features of SCTATs include the presence of highly cellular aspirates forming simple and complex rosette-like structures around central rounded hyaline material, small nucleoli, and prominent nuclear grooves. These cytologic findings are clearly distinct from the poorly formed rosette-like structures of granulosa-cell tumors and are reminiscent of the low-power appearance of the cribriform variant of adenoid cystic carcinoma. The fine needle aspiration cytologic features of only two other cases have been previously described and, to the best of our knowledge, this is the first case reporting the cytologic diagnosis of a distant metastasis of a SCTATs by endoscopic ultrasound-guided fine needle aspiration. In this case, the distinctive and characteristic cytologic features have allowed the proper diagnosis of a distant metastasis of SCTATs. Diagn. Cytopathol. 2006;34:576,579. © 2006 Wiley-Liss, Inc. [source] Fine-needle aspiration of apocrine hidrocystoma,A potential mimic of papillary neoplasms metastasizing to the skinDIAGNOSTIC CYTOPATHOLOGY, Issue 4 2004Miguel Pérez-Guillermo M.D. Abstract We report the cytologic features of a histologically confirmed apocrine hidrocystoma as seen in fine-needle aspirates. The main cytologic features were the presence of sparse pseudopapillae with mild to moderate atypia in a background of an amorphous navy blue material reminiscent of that seen in aspirates of colloid nodules of the thyroid gland. The pseudopapillae were mistaken for malignant metastatic deposits. It is suggested that the presence of pseudopapillae in aspirates obtained from cutaneous nodules might be a clue for a tentative diagnosis of benign tumors of epidermal adnexae, with the proviso that a primary malignant tumor be ruled out first. Diagn. Cytopathol. 2004;30:275,279. © 2004 Wiley-Liss, Inc. [source] Enjoying the saints in late antiquityEARLY MEDIEVAL EUROPE, Issue 1 2000Peter Brown The discovery at Mainz by Fran,ois Dolbeau of a new collection of sermons of Augustine has enabled us to study, in far greater detail, the attitude of Augustine to the reform of the cult of the martyrs between 391 and 404. This study aims to understand Augustine's insistence on the need to imitate the martyrs against the background of his views on grace and the relation of such views to the growing differentiation of the Christian community. It also attempts to do justice to the views of those he criticized: others regarded the triumph of the martyrs over pain and death as a unique manifestation of the power of God, in which believers participated, not through imitation but through celebrations reminiscent of the joy of pagan festivals. In this debate, Augustine by no means had the last word. The article attempts to show the continuing tension between notions of the saints as imitable and inimitable figures in the early medieval period, and more briefly, by implication, in all later centuries. [source] Staphylococcus aureus Infective Endocarditis Mimicking a Hydatid CystECHOCARDIOGRAPHY, Issue 8 2010Jeroen Walpot M.D. We report an atypical echocardiographic presentation of Staphylococcus aureus infective endocarditis (IE) of the mitral valve in an octogenarian female. Echocardiography revealed perforation of the anterior mitral valve leaflet (AMVL), with a large cystic mass seemingly attached to the AMVL and surrounded by a thin membranous structure. These images were strongly reminiscent of a hydatid cyst. The significant comorbidity of the patient did not justify an urgent surgical approach, and the patient subsequently expired of cardiogenic and septic shock. Autopsy revealed a large vegetation attached to the interatrial septum in the immediate proximity of the AMVL, without signs of the membranous structure and without pathological evidence for septic embolism. This atypical presentation of IE prompted us to discuss a brief review of intracardiac cystic masses. (Echocardiography 2010;27:E80-E82) [source] TACIT COLLUSION IN AUCTIONS AND CONDITIONS FOR ITS FACILITATION AND PREVENTION: EQUILIBRIUM SELECTION IN LABORATORY EXPERIMENTAL MARKETSECONOMIC INQUIRY, Issue 3 2009JIN LI The paper studies bidder behavior in simultaneous, continuous, ascending price auctions. We design and implement a "collusion incubator" environment based on a type of public, symmetrically "folded" and "item-aligned" preferences. Tacit collusion develops quickly and reliably within the environment. Once tacit collusion developed, it proved remarkably robust to institutional changes that weakened it as an equilibrium of a game-theoretic model. The only successful remedy was a non-public change in the preference of participants that destroyed the symmetrically, "folded" and "item aligned" patterns of preferences, creating head-to-head competition between two agents reminiscent of the concept of a "maverick."(JEL L50, L94, D43) [source] Indications for cell stress in response to adenoviral and baculoviral gene transfer observed by proteome profiling of human cancer cellsELECTROPHORESIS, Issue 11 2010Christopher Gerner Abstract Gene transfer to cultured cells is an important tool for functional studies in many areas of biomedical research and vector systems derived from adenoviruses and baculoviruses are frequently used for this purpose. In order to characterize how viral gene transfer vectors affect the functional state of transduced cells, we applied 2-D PAGE allowing quantitative determination of protein amounts and synthesis rates of metabolically labeled cells and shotgun proteomics. Using HepG2 human hepatoma cells we show that both vector types can achieve efficient expression of green fluorescent protein, which accounted for about 0.1% of total cellular protein synthesis 72,h after transduction. No evidence in contrast was found for expression of proteins from the viral backbones. With respect to the host cell response, both vectors induced a general increase in protein synthesis of about 50%, which was independent of green fluorescent protein expression. 2-D PAGE autoradiographs identified a 3.6-fold increase of ,-actin synthesis in adenovirus transduced cells. In addition shotgun proteomics of cytoplasmic and nuclear extract fractions identified a slight induction of several proteins related to inflammatory activation, cell survival and chromatin function by both virus types. These data demonstrate that commonly used gene transfer vectors induce a response reminiscent of stress activation in host cells, which needs to be taken into account when performing functional assays with transduced cells. [source] Ecotype diversity in the marine picoeukaryote Ostreococcus (Chlorophyta, Prasinophyceae)ENVIRONMENTAL MICROBIOLOGY, Issue 6 2005Francisco Rodríguez Summary The importance of the cyanobacteria Prochlorococcus and Synechococcus in marine ecosystems in terms of abundance and primary production can be partially explained by ecotypic differentiation. Despite the dominance of eukaryotes within photosynthetic picoplankton in many areas a similar differentiation has never been evidenced for these organisms. Here we report distinct genetic [rDNA 18S and internal transcribed spacer (ITS) sequencing], karyotypic (pulsed-field gel electrophoresis), phenotypic (pigment composition) and physiological (light-limited growth rates) traits in 12 Ostreococcus strains (Prasinophyceae) isolated from various marine environments and depths, which suggest that the concept of ecotype could also be valid for eukaryotes. Internal transcribed spacer phylogeny grouped together four deep strains isolated between 90 m and 120 m depth from different geographical origins. Three deep strains displayed larger chromosomal bands, different chromosome hybridization patterns, and an additional chlorophyll (chl) c -like pigment. Furthermore, growth rates of deep strains show severe photo-inhibition at high light intensities, while surface strains do not grow at the lowest light intensities. These features strongly suggest distinct adaptation to environmental conditions encountered at surface and the bottom of the oceanic euphotic zone, reminiscent of that described in prokaryotes. [source] Impaired estrogen-induced negative feedback on gonadotropin secretion in patients with gonadotropin-secreting and nonfunctioning pituitary adenomasEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2002A. Lania Abstract Background Several in vitro studies suggest that gonadotropin-secreting pituitary adenomas (Gn-omas) and non functioning pituitary adenomas (NFPA) originate from gonadotroph cells. Patients with Gn-oma and NFPA frequently show abnormal gonadotropin response to TRH. The aim of the study was to investigate whether the estrogen-induced negative feedback is operating in either patients with Gn-oma or NFPA. Materials and methods Serum gonadotropin levels were evaluated at 24 h after ethinylestradiol administration (1 mg per os; EE2 test) in seven patients with a diagnosis of Gn-oma, based on the presence of high follicle-stimulating hormone (FSH) and/or lutenising hormone (LH) levels with normal or high levels of sex steroids, in 22 patients with NFPA with normal or low levels of gonadotropin and sex steroids, and 30 sex- and age-matched healthy subjects. A normal response to EE2 test was arbitrarily defined as a serum LH and FSH decrease of at least 40 and 30% below basal levels. Results Among patients with Gn-oma, only one had a normal FSH inhibition and another, a normal LH inhibition. Among the 22 patients with NFPA, the EE2 test caused a normal FSH or LH reduction in 10 and 15, respectively, while a normal reduction of both FSH and LH was observed in nine. Conclusions The study demonstrates that estrogen-induced negative feedback of gonadotropin secretion is disrupted in almost all patients with Gn-oma and in half of those with NFPA. This defective feedback is reminiscent of the resistance to thyroid hormones and glucocorticoids observed in patients with thyroid-stimulating hormone- (TSH-) and adrenocorticotropic hormone- (ACTH-)secreting adenomas, respectively. [source] PRECLINICAL STUDY: FULL ARTICLE: Altered architecture and functional consequences of the mesolimbic dopamine system in cannabis dependenceADDICTION BIOLOGY, Issue 3 2010Saturnino Spiga ABSTRACT Cannabinoid withdrawal produces a hypofunction of mesencephalic dopamine neurons that impinge upon medium spiny neurons (MSN) of the forebrain. After chronic treatment with two structurally different cannabinoid agonists, ,9 -tetrahydrocannabinol and CP55 940 (CP) rats were withdrawn spontaneously and pharmacologically with the CB1 antagonist SR141716A (SR). In these two conditions, evaluation of tyrosine hydroxylase (TH)-positive neurons revealed significant morphometrical reductions in the ventrotegmental area but not substantia nigra pars compacta of withdrawn rats. Similarly, confocal analysis of Golgi,Cox-stained sections of the nucleus accumbens revealed a decrease in the shell, but not the core, of the spines' density of withdrawn rats. Administration of the CB1 antagonist SR to control rats, provoked structural abnormalities reminiscent of those observed in withdrawal conditions and support the regulatory role of cannabinoids in neurogenesis, axonal growth and synaptogenesis by acting as eu-proliferative signals through the CB1 receptors. Further, these measures were incorporated into a realistic computational model that predicts a strong reduction in the excitability of morphologically altered MSN, yielding a significant reduction in action potential output. These pieces of evidence support the tenet that withdrawal from addictive compounds alters functioning of the mesolimbic system and provide direct morphological evidence for functional abnormalities associated with cannabinoid dependence at the level of dopaminergic neurons and their postsynaptic counterpart and are coherent with recent hypothesis underscoring a hypodopaminergic state as a distinctive feature of the ,addicted brain'. [source] Development of nephritis but not sialadenitis in autoimmune-prone BAFF transgenic mice lacking marginal zone B cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2006Carrie Abstract B cell-activating factor belonging to the TNF family (BAFF) is a B cell survival factor required for B cell maturation. BAFF transgenic (Tg) mice develop autoimmune disorders characterized by autoantibody production, which leads to nephritis and salivary gland destruction (sialadenitis), features reminiscent of systemic lupus erythematosus and Sjögren's syndrome (SS), respectively. Disease in BAFF Tg mice correlates with the expansion of the marginal zone (MZ) B cell compartment and the abnormal presence of MZ-like B cells in the blood, LN and inflamed salivary glands, suggesting a role for these cells in BAFF-induced autoimmunity. Lymphotoxin-, (LT,)-deficient mice show disrupted splenic architecture, lack MZ B cells and some peripheral LN, and are unable to mount T cell-dependent immune responses. BAFF Tg mice lacking LT, (LT,,-BTg) retained these defects, yet still developed nephritis associated with the presence of B-1 B cells in the kidneys. However, in contrast to old BAFF Tg mice, aging LT,,-BTg mice no longer developed sialadenitis. Thus, autoimmune disorders in BAFF Tg mice are possibly events coordinated by MZ and B-1 B cells at separate anatomical sites. [source] hypercloso -Hexa(amino)hexaboranes: Structurally Related to Known hypercloso -Dodecaboranes, Metastable with Regard to Their Classical CycloisomersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2009Wahid Mesbah Abstract B6(NMe2)6 (2a) is the first neutral hypercloso -hexaborane to be characterized by X-ray structural analysis. The geometry of 2a is in nice agreement with that of the Ci symmetric molecule computed at the B3LYP/6-311+G** level of theory. Two B3 triangles with long B···B distances in 2a are reminiscent of those in Hawthorne's benzyloxy-substituted hypercloso -dodecaboranes 6a,b. Upon heating to 200 °C, 2a transforms into Nöth's classical cyclohexaborane 1a. Computations at the B3LYP/6-311+G** + ZPE level of theory show 1a to be 21.6 kcal,mol,1lower in energy than 2a, that is, the latter is metastable. hypercloso -Hexaborane B6(NEt2)6 (2b), which was reported to be thermodynamically more stable than 1b, is computed to be 22.4 kcal,mol,1less stable than 1b. Pure 1b is shown here not to transform into 2b upon standing in solution, which is in contrast to reports in the literature for a mixture containing 1b. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] The SDF-1/CXCR4 pathway and the development of the cerebellar systemEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2005Tim O. Vilz Abstract Mice deficient for the chemokine receptor CXCR4 show premature translocation of granule cell neuroblasts from their germinal zone into the nascent cerebellum [Y.-R. Zuo et al. (1998)Nature, 393, 595,599]. Here, we used CXCR4-null mice to analyse the early development of cerebellar cortical inhibitory interneurons and pontine neurons which, in the adult, are synaptically integrated with granule cells. Cortical inhibitory interneuronal precursors normally invade the cerebellar anlage of CXCR4-deficient mice, but their dispersal is impeded by dislocated foci of proliferating granule cells, from which they are excluded. This is reminiscent of the strict exclusion of inhibitory interneuronal precursors from the superficial external granule cell layer. As inhibitory interneuronal precursors readily mingle with post-mitotic granule cells both in wild-type and CXCR4-null mice, these findings indicate that the developmentally regulated interactions between granule and inhibitory interneuronal precursors are independent of SDF-1/CXCR4 signalling. In contrast, the transit of pontine neurons from the rhombic lip through the anterior extramural stream to the basilar pons is disrupted in CXCR4-deficient animals. Migrating pontine neurons express CXCR4, and in CXCR4-null animals these cells are found displaced deep into the brainstem. Consequently, nascent pontine nuclei in CXCR4-deficient animals are hypoplastic. Moreover, they fail to express plexin D1, suggesting that SDF-1/CXCR4 signalling may also impinge on axon guidance critical to the orderly formation of granule cell mossy fibre afferents. [source] Adult neural progenitor cells provide a permissive guiding substrate for corticospinal axon growth following spinal cord injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2004Katharina Pfeifer Abstract Adult neural progenitor cells (NPC) are an attractive source for cell transplantation and neural tissue replacement after central nervous system (CNS) injury. Following transplantation of NPC cell suspensions into the acutely injured rat spinal cord, NPC survive; however, they migrate away from the lesion site and are unable to replace the injury-induced lesion cavity. In the present study we examined (i) whether NPC can be retained within the lesion site after co-transplantation with primary fibroblasts, and (ii) whether NPC promote axonal regeneration following spinal cord injury. Co-cultivation of NPC with fibroblasts demonstrated that NPC adhere to fibroblasts and the extracellular matrix produced by fibroblasts. In the presence of fibroblasts, the differentiation pattern of co-cultivated NPC was shifted towards glial differentiation. Three weeks after transplantation of adult spinal-cord-derived NPC with primary fibroblasts as mixed cell suspensions into the acutely injured cervical spinal cord in adult rats, the lesion cavity was completely replaced. NPC survived throughout the graft and differentiated exclusively into glial cells. Quantification of neurofilament-labeled axons and anterogradely labeled corticospinal axons indicated that NPC co-grafted with fibroblasts significantly enhanced axonal regeneration. Both neurofilament-labeled axons and corticospinal axons aligned longitudinally along GFAP-expressing NPC-derived cells, which displayed a bipolar morphology reminiscent of immature astroglia. Thus, grafted astroglial differentiated NPC promote axon regrowth following spinal cord injury by means of cellular guidance. [source] Age-dependent cognitive decline in the APP23 model precedes amyloid depositionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003Debby Van Dam Abstract Heterozygous APP23 mice, expressing human amyloid-precursor protein with the Swedish double mutation and control littermates, were subjected to behavioral and neuromotor tasks at the age of 6,8 weeks, 3 and 6 months. A hidden-platform Morris-type water maze showed an age-dependent decline of spatial memory capacities in the APP23 model. From the age of 3 months onwards, the APP23 mice displayed major learning and memory deficits as demonstrated by severely impaired learning curves during acquisition and impaired probe trial performance. In addition to the cognitive deficit, APP23 mice displayed disturbed activity patterns. Overnight cage-activity recording showed hyperactivity in the transgenics for the three age groups tested. However, a short 2-h recording during dusk phase demonstrated lower activity levels in 6-month-old APP23 mice as compared to controls. Moreover, at this age, APP23 mice differed from control littermates in exploration and activity levels in the open-field paradigm. These findings are reminiscent of disturbances in circadian rhythms and activity observed in Alzheimer patients. Determination of plaque-associated human amyloid-,1,42 peptides in brain revealed a fivefold increase in heterozygous APP23 mice at 6 months as compared to younger transgenics. This increase coincided with the first appearance of plaques in hippocampus and neocortex. Spatial memory deficits preceded plaque formation and increase in plaque-associated amyloid-,1,42 peptides, but probe trial performance did correlate negatively with soluble amyloid-, brain concentration in 3-month-old APP23 mutants. Detectable plaque formation is not the (only) causal factor contributing to memory defects in the APP23 model. [source] Personality terms of abuse in three cultures: type nouns between description and insultEUROPEAN JOURNAL OF PERSONALITY, Issue 2 2005Boele De Raad In this study terms of abuse are investigated in three different cultures. Spontaneous verbal aggression is to a certain extent reminiscent of the values of a certain culture. One hundred and ninety-two male subjects from Spain, Germany and the Netherlands were asked to write down terms of abuse that they would use given a certain stimulus situation, and in addition to give their rating of the offensive character of those terms. A total set of 830 useful expressions was thus collected. The frequencies of the expressions were established, and the total list of expressions was categorized in terms of what they were about. In Spanish abusive language is typically about family and relations, in Germany it is typically about anal aspects, and in the Netherlands it is mainly about genitals. Explanations are provided in terms of dimensions on which the three cultures differ. Copyright © 2004 John Wiley & Sons, Ltd. [source] ESTIMATING A GEOGRAPHICALLY EXPLICIT MODEL OF POPULATION DIVERGENCEEVOLUTION, Issue 3 2007L. Lacey Knowles Patterns of genetic variation can provide valuable insights for deciphering the relative roles of different evolutionary processes in species differentiation. However, population-genetic models for studying divergence in geographically structured species are generally lacking. Since these are the biogeographic settings where genetic drift is expected to predominate, not only are population-genetic tests of hypotheses in geographically structured species constrained, but generalizations about the evolutionary processes that promote species divergence may also be potentially biased. Here we estimate a population-divergence model in montane grasshoppers from the sky islands of the Rocky Mountains. Because this region was directly impacted by Pleistocene glaciation, both the displacement into glacial refugia and recolonization of montane habitats may contribute to differentiation. Building on the tradition of using information from the genealogical relationships of alleles to infer the geography of divergence, here the additional consideration of the process of gene-lineage sorting is used to obtain a quantitative estimate of population relationships and historical associations (i.e., a population tree) from the gene trees of five anonymous nuclear loci and one mitochondrial locus in the broadly distributed species Melanoplus oregonensis. Three different approaches are used to estimate a model of population divergence; this comparison allows us to evaluate specific methodological assumptions that influence the estimated history of divergence. A model of population divergence was identified that significantly fits the data better compared to the other approaches, based on per-site likelihood scores of the multiple loci, and that provides clues about how divergence proceeded in M. oregonensis during the dynamic Pleistocene. Unlike the approaches that either considered only the most recent coalescence (i.e., information from a single individual per population) or did not consider the pattern of coalescence in the gene genealogies, the population-divergence model that best fits the data was estimated by considering the pattern of gene lineage coalescence across multiple individuals, as well as loci. These results indicate that sampling of multiple individuals per population is critical to obtaining an accurate estimate of the history of divergence so that the signal of common ancestry can be separated from the confounding influence of gene flow,even though estimates suggest that gene flow is not a predominant factor structuring patterns of genetic variation across these sky island populations. They also suggest that the gene genealogies contain information about population relationships, despite the lack of complete sorting of gene lineages. What emerges from the analyses is a model of population divergence that incorporates both contemporary distributions and historical associations, and shows a latitudinal and regional structuring of populations reminiscent of population displacements into multiple glacial refugia. Because the population-divergence model itself is built upon the specific events shaping the history of M. oregonensis, it provides a framework for estimating additional population-genetic parameters relevant to understanding the processes governing differentiation in geographically structured species and avoids the problems of relying on overly simplified and inaccurate divergence models. The utility of these approaches, as well as the caveats and future improvements, for estimating population relationships and historical associations relevant to genetic analyses of geographically structured species are discussed. [source] THE DIFFUSIVE SPREAD OF ALLELES IN HETEROGENEOUS POPULATIONSEVOLUTION, Issue 3 2004Garrick T. Skalski Abstract The spread of genes and individuals through space in populations is relevant in many biological contexts. I study, via systems of reaction-diffusion equations, the spatial spread of advantageous alleles through structured populations. The results show that the temporally asymptotic rate of spread of an advantageous allele, a kind of invasion speed, can be approximated for a class of linear partial differential equations via a relatively simple formula, c= 2,rD, that is reminiscent of a classic formula attributed to R. A. Fisher. The parameters r and D, represent an asymptotic growth rate and an average diffusion rate, respectively, and can be interpreted in terms of eigenvalues and eigenvectors that depend on the population's demographic structure. The results can be applied, under certain conditions, to a wide class of nonlinear partial differential equations that are relevant to a variety of ecological and evolutionary scenarios in population biology. I illustrate the approach for computing invasion speed with three examples that allow for heterogeneous dispersal rates among different classes of individuals within model populations. [source] THE POPULATION GENETICS OF ADAPTATION: THE ADAPTATION OF DNA SEQUENCESEVOLUTION, Issue 7 2002H. Allen Orr Abstract I describe several patterns characterizing the genetics of adaptation at the DNA level. Following Gillespie (1983, 1984, 1991), I consider a population presently fixed for the ith best allele at a locus and study the sequential substitution of favorable mutations that results in fixation of the fittest DNA sequence locally available. Given a wild type sequence that is less than optimal, I derive the fitness rank of the next allele typically fixed by natural selection as well as the mean and variance of the jump in fitness that results when natural selection drives a substitution. Looking over the whole series of substitutions required to reach the best allele, I show that the mean fitness jumps occurring throughout an adaptive walk are constrained to a twofold window of values, assuming only that adaptation begins from a reasonably fit allele. I also show that the first substitution and the substitution of largest effect account for a large share of the total fitness increase during adaptation. I further show that the distribution of selection coefficients fixed throughout such an adaptive walk is exponential (ignoring mutations of small effect), a finding reminiscent of that seen in Fisher's geometric model of adaptation. Last, I show that adaptation by natural selection behaves in several respects as the average of two idealized forms of adaptation, perfect and random. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||