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1.
F Klein V Lemaire C Sandi S Vitiello J Van der Logt P E Laurent P Neveu M Le Moal P Mormède 《Life sciences》1992,50(10):723-731
The influence of a chronic social stress upon immunity was investigated in Wistar rats, submitted for four weeks to two different behavioral situations, balanced in a factorial design: housing with three females and membership rotation. The combination of these two factor led to adrenal enlargement (43.3%), thymus involution (39.5%) and increased basal corticosterone levels, all indices of activation of the hypothalamic-hypophysis-adrenal axis. However, neither natural killer cell activity, splenocyte reactivity to mitogen nor the rate of spontaneous development of antibodies against Mycoplasma pulmonis, a common pathogen of the respiratory tract, were changed in the endocrine activated animals. Analysis of the data on kinetics of stress at 1, 7 and 28 days after the initial mixing of the animals gave the same results. These data question the immunosuppressant activity usually conferred to corticosteroids, at least when adrenal hyperactivity is induced by chronic environmental stressors. 相似文献
2.
The role of NCAM in auditory fear conditioning and its modulation by stress: a focus on the amygdala
Chronic stress in rodents was shown to induce structural shrinkage and functional alterations in the hippocampus that were linked to spatial memory impairments. Effects of chronic stress on the amygdala have been linked to a facilitation of fear conditioning. Although the underlying molecular mechanisms are still poorly understood, increasing evidence highlights the neural cell adhesion molecule (NCAM) as an important molecular mediator of stress‐induced structural and functional alterations. In this study, we investigated whether altered NCAM expression levels in the amygdala might be related to stress‐induced enhancement of auditory fear conditioning and anxiety‐like behavior. In adult C57BL/6J wild‐type mice, chronic unpredictable stress resulted in an isoform‐specific increase of NCAM expression (NCAM‐140 and NCAM‐180) in the amygdala, as well as enhanced auditory fear conditioning and anxiety‐like behavior. Strikingly, forebrain‐specific conditional NCAM‐deficient mice (NCAM‐floxed mice that express the cre‐recombinase under the control of the promoter of the α‐subunit of the calcium‐calmodulin‐dependent protein kinase II), whose amygdala NCAM expression levels are reduced, displayed impaired auditory fear conditioning which was not altered following chronic stress exposure. Likewise, chronic stress in these conditional NCAM‐deficient mice did not modify NCAM expression levels in the amygdala or hippocampus, while they showed enhanced anxiety‐like behavior, questioning the involvement of NCAM in this type of behavior. Together, our results strongly support the involvement of NCAM in the amygdala in the consolidation of auditory fear conditioning and highlight increased NCAM expression in the amygdala among the mechanisms whereby stress facilitates fear conditioning processes. 相似文献
3.
Hilda Mirbaha Dailu Chen Vishruth Mullapudi Sandi Jo Terpack Charles L. White III Lukasz A. Joachimiak Marc I. Diamond 《The Journal of biological chemistry》2022,298(8)
Tau aggregation into ordered assemblies causes neurodegenerative tauopathies. We previously reported that tau monomer exists in either inert (Mi) or seed-competent (Ms) conformational ensembles and that Ms encodes strains, that is, unique, self-replicating, biologically active assemblies. It is unknown if disease begins with Ms formation followed by fibril assembly or if Ms derives from fibrils and is therefore an epiphenomenon. Here, we studied a tauopathy mouse model (PS19) that expresses full-length mutant human (1N4R) tau (P301S). Insoluble tau seeding activity appeared at 2 months of age and insoluble tau protein assemblies by immunoblot at 3 months. Tau monomer from mice aged 1 to 6 weeks, purified using size-exclusion chromatography, contained soluble seeding activity at 4 weeks, before insoluble material or larger assemblies were observed, with assemblies ranging from n = 1 to 3 tau units. By 5 to 6 weeks, large soluble assemblies had formed. This indicated that the first detectable pathological forms of tau were in fact Ms. We next examined posttranslational modifications of tau monomer from 1 to 6 weeks. We detected no phosphorylation unique to Ms in PS19 or human Alzheimer’s disease brains. We conclude that tauopathy begins with formation of the Ms monomer, whose activity is phosphorylation independent. Ms then self assembles to form oligomers before it forms insoluble fibrils. The conversion of tau monomer from Mi to Ms thus constitutes the first detectable step in the initiation of tauopathy in this mouse model, with obvious implications for the origins of tauopathy in humans. 相似文献
4.
AimWe incorporated genetic structure and life history phase in species distribution models (SDMs) constructed for a widespread spiny lobster, to reveal local adaptations specific to individual subspecies and predict future range shifts under the RCP 8.5 climate change scenario.LocationIndo‐West Pacific.MethodsMaxEnt was used to construct present‐day SDMs for the spiny lobster Panulirus homarus and individually for the three genetically distinct subspecies of which it comprises. SDMs incorporated both sea surface and benthic (seafloor) climate layers to recreate discrete influences of these habitats during the drifting larval and benthic juvenile and adult life history phases. Principle component analysis (PCA) was used to infer environmental variables to which individual subspecies were adapted. SDM projections of present‐day habitat suitability were compared with predictions for the year 2,100, under the RCP 8.5 climate change scenario.ResultsIn the PCA, salinity best explained P. h. megasculptus habitat suitability, compared with current velocity in P. h. rubellus and sea surface temperature in P. h. homarus. Drifting and benthic life history phases were adapted to different combinations of sea surface and benthic environmental variables considered. Highly suitable habitats for benthic phases were spatially enveloped within more extensive sea surface habitats suitable for drifting larvae. SDMs predicted that present‐day highly suitable habitats for P. homarus will decrease by the year 2,100.Main conclusionsIncorporating genetic structure in SDMs showed that individual spiny lobster subspecies had unique adaptations, which could not be resolved in species‐level models. The use of sea surface and benthic climate layers revealed the relative importance of environmental variables during drifting and benthic life history phases. SDMs that included genetic structure and life history were more informative in predictive models of climate change effects. 相似文献
5.
Jesús Alejandro Zamora-Briseo Alejandro Pereira-Santana Sandi Julissa Reyes-Hernndez Daniel Cerqueda-García Enrique Castao Luis Carlos Rodríguez-Zapata 《Cell stress & chaperones》2021,26(1):141
Intrinsic protein disorder is an interesting structural feature where fully functional proteins lack a three-dimensional structure in solution. In this work, we estimated the relative content of intrinsic protein disorder in 96 plant proteomes including monocots and eudicots. In this analysis, we found variation in the relative abundance of intrinsic protein disorder among these major clades; the relative level of disorder is higher in monocots than eudicots. In turn, there is an inverse relationship between the degree of intrinsic protein disorder and protein length, with smaller proteins being more disordered. The relative abundance of amino acids depends on intrinsic disorder and also varies among clades. Within the nucleus, intrinsically disordered proteins are more abundant than ordered proteins. Intrinsically disordered proteins are specialized in regulatory functions, nucleic acid binding, RNA processing, and in response to environmental stimuli. The implications of this on plants’ responses to their environment are discussed. 相似文献
6.
Chiranjeevi Tikka Hari Prasad Osuru Navya Atluri Praveen Chakravarthi Veera Raghavulu Nanda Kumar yellapu Ismail Shaik Mannur Uppu Venkateswara Prasad Sudheer Aluru Narasimha Varma K Matcha Bhaskar 《Bioinformation》2013,9(8):421-425
Yeast strains are commonly associated with sugar rich environments. Various fruit samples were selected as source for isolating
yeast cells. The isolated cultures were identified at Genus level by colony morphology, biochemical characteristics and cell
morphological characters. An attempt has been made to check the viability of yeast cells under different concentrations of ethanol.
Ethanol tolerance of each strain was studied by allowing the yeast to grow in liquid YEPD (Yeast Extract Peptone Dextrose)
medium having different concentrations of ethanol. A total of fifteen yeast strains isolated from different samples were used for the
study. Seven strains of Saccharomyces cerevisiae obtained from different fruit sources were screened for ethanol tolerance. The
results obtained in this study show a range of tolerance levels between 7%-12% in all the stains. Further, the cluster analysis based
on 22 RAPD (Random Amplified polymorphic DNA) bands revealed polymorphisms in these seven Saccharomyces strains. 相似文献
7.
Christine Kohl Orbicia Riccio Jocelyn Grosse Olivia Zanoletti Céline Fournier Mathias V. Schmidt Carmen Sandi 《PloS one》2013,8(2)
Disturbances of the excitation/inhibition (E/I) balance in the brain were recently suggested as potential factors underlying disorders like autism and schizophrenia resulting in associated behavioral alterations including changes in social and emotional behavior as well as abnormal aggression. Neuronal cell adhesion molecules (nCAMs) and mutations in these genes were found to be strongly implicated in the pathophysiology of these disorders. Neuroligin2 (nlgn2) is a postsynaptic cell adhesion molecule, which is predominantly expressed at inhibitory synapses and required for synapse specification and stabilization. Changes in the expression of nlgn2 were shown to result in alterations of social behavior as well as altered inhibitory synaptic transmission, hence modifying the E/I balance. In our study, we focused on the role of nlgn2 in the dorsal hippocampus in the regulation of emotional and social behaviors. To this purpose, we injected an AAV construct overexpressing nlgn2 in the hippocampus of rats and investigated the effects on behavior and on markers for the E/I ratio. We could show an increase in GAD65, a GABA-synthesizing protein in neuronal terminals, and furthermore, reduced exploration of novel stimuli and less offensive behavior. Our data suggest nlgn2 in the hippocampus to be strongly implicated in maintaining the E/I balance in the brain and thereby modulating social and emotional behavior. 相似文献
8.
Human adenovirus has evolved to infect and replicate in terminally differentiated human epithelial cells, predominantly those within the airway, the gut, or the eye. To overcome the block to viral DNA replication present in these cells, the virus expresses the Early 1A proteins (E1A). These immediate early proteins drive cells into S-phase and induce expression of all other viral early genes. During infection, several E1A isoforms are expressed with proteins of 289, 243, 217, 171, and 55 residues being present for human adenovirus type 5. Here we examine the contribution that the two largest E1A isoforms make to the viral life cycle in growth-arrested normal human fibroblasts. Viruses that express E1A289R were found to replicate better than those that do not express this isoform. Importantly, induction of several viral genes was delayed in a virus expressing E1A243R, with several viral structural proteins undetectable by western blot. We also highlight the changes in E1A isoforms detected during the course of viral infection. Furthermore, we show that viral DNA replication occurs more efficiently, leading to higher number of viral genomes in cells infected with viruses that express E1A289R. Finally, induction of S-phase specific genes differs between viruses expressing different E1A isoforms, with those having E1A289R leading to, generally, earlier activation of these genes. Overall, we provide an overview of adenovirus replication using modern molecular biology approaches and further insights into the contribution that E1A isoforms make to the life cycle of human adenovirus in arrested human fibroblasts. 相似文献
9.
Sara Anjomani Virmouni Vahid Ezzatizadeh Chiranjeevi Sandi Madhavi Sandi Sahar Al-Mahdawi Yogesh Chutake Mark A. Pook 《Disease models & mechanisms》2015,8(3):225-235
Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by a GAA repeat expansion mutation within intron 1 of the FXN gene, resulting in reduced levels of frataxin protein. We have previously reported the generation of human FXN yeast artificial chromosome (YAC) transgenic FRDA mouse models containing 90–190 GAA repeats, but the presence of multiple GAA repeats within these mice is considered suboptimal. We now describe the cellular, molecular and behavioural characterisation of a newly developed YAC transgenic FRDA mouse model, designated YG8sR, which we have shown by DNA sequencing to contain a single pure GAA repeat expansion. The founder YG8sR mouse contained 120 GAA repeats but, due to intergenerational expansion, we have now established a colony of YG8sR mice that contain ~200 GAA repeats. We show that YG8sR mice have a single copy of the FXN transgene, which is integrated at a single site as confirmed by fluorescence in situ hybridisation (FISH) analysis of metaphase and interphase chromosomes. We have identified significant behavioural deficits, together with a degree of glucose intolerance and insulin hypersensitivity, in YG8sR FRDA mice compared with control Y47R and wild-type (WT) mice. We have also detected increased somatic GAA repeat instability in the brain and cerebellum of YG8sR mice, together with significantly reduced expression of FXN, FAST-1 and frataxin, and reduced aconitase activity, compared with Y47R mice. Furthermore, we have confirmed the presence of pathological vacuoles within neurons of the dorsal root ganglia (DRG) of YG8sR mice. These novel GAA-repeat-expansion-based YAC transgenic FRDA mice, which exhibit progressive FRDA-like pathology, represent an excellent model for the investigation of FRDA disease mechanisms and therapy.KEY WORDS: GAA repeat, Friedreich’s ataxia, FRDA, YG8sR, Mouse model 相似文献
10.
Rajesh Kumar G Mrudula Spurthi K Kishore Kumar G Mohanalatha Kurapati Saraswati M Mohini Aiyengar T Chiranjeevi P Srilatha Reddy G Nivas S Kaushik P Sanjib Sahu K Surekha Rani H 《PloS one》2015,10(3)