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1.
J Anal Psychol ; 68(2): 436-439, 2023 04.
Article in English | MEDLINE | ID: mdl-36807256

Subject(s)
Jungian Theory , Humans
2.
Biochem Mol Biol Educ ; 50(1): 65-74, 2022 01.
Article in English | MEDLINE | ID: mdl-34668638

ABSTRACT

The employability of science graduates if of key concern. Employers report that STEM graduates lack appropriate employability skills and work experience, and science graduates take longer to find full-time work than graduates from many other programs. Undergraduate research experience (URE) is an important pedagogy that involves student immersion in a professional research environment-as such it provides an opportunity for science students to develop their understanding of the world of work, and of their own developing employability. In this study, we examine students' reflections on their URE learnings and their resultant perceived employability. We ask whether students understand the value of the URE as an employability development vehicle and consider what can be done to improve the employability learnings from the URE. The results show that students articulate multiple learnings from their UREs, but they struggle to translate these learnings into an employability or non-research-work context. We conclude that UREs are important opportunities to learn about work in science, but that URE students would benefit from URE curriculum components that foreground the way UREs can help develop students' employability. The insights from this study can help inform and refine future URE programs to improve their efficacy as vehicles to benefit graduate employability.


Subject(s)
Curriculum , Students , Humans , Learning
3.
Front Cell Neurosci ; 13: 55, 2019.
Article in English | MEDLINE | ID: mdl-30842728

ABSTRACT

Primary cilia are microtubule-based organelles that are typically present on cells during the G0 or G1-S/G2 phases of the cell cycle. Recent studies of glioblastoma (GBM) biopsies, a brain tumor that is notorious for its aggressive growth and resistance to treatment, show that many cells in the tumor lack cilia. At this point, it remains unclear whether primary cilia promote or suppress glioma tumorigenesis. In this review, we will discuss the different roles that have been proposed for primary cilia in glioma and how cilia may contribute to the resistance of these tumors to current therapies.

4.
Article in English | MEDLINE | ID: mdl-29904535

ABSTRACT

The ability to communicate is a crucial graduate outcome for science students; however, crowded curricula and large class sizes make it difficult to find time to explicitly teach foundational communication skills. In response to these challenges, we developed an online resource called Communication Learning in Practice for Scientists, or CLIPS. CLIPS provides a multi-point mentoring model that has allowed us to successfully integrate the teaching and learning of a complex set of tacitly-understood skills across multiple scientific disciplines. It also provides a flexible way for industry experts, academics, and students to learn from one another's experiences of, and expertise in, science communication. CLIPS leverages the student focus on assessment; students access CLIPS for pragmatic, detailed, and consistent advice when undertaking assessment tasks. In creating CLIPS, our philosophy was that communication is the core business of any scientific practice, not an add-on after the event. Extensive, repeated use of CLIPS by both students and academics indicates that the resource and its delivery model are considered useful, respected, and impactful for, and by, the intended audiences. We have provided CLIPS to the science education community through www.clips.edu.au.

5.
Biochem Mol Biol Educ ; 46(3): 213-222, 2018 05.
Article in English | MEDLINE | ID: mdl-29383870

ABSTRACT

Course-integrated Undergraduate Research Experiences (CUREs) involve large numbers of students in real research. We describe a late-year microbiology CURE in which students use yeast to address a research question around beer brewing or synthesizing biofuel; the interdisciplinary student-designed project incorporates genetics, bioinformatics, biochemistry, analytical chemistry, and microbiology. Students perceived significant learning gains around multiple technical and "becoming a scientist" aspects of the project. The project is demanding for both the students and the academic implementers. We examine the rich landscape of support and interaction that this CURE both encourages and requires while also considering how we can support the exercise better and more sustainably. The findings from this study provide a picture of a CURE implementation that has begun to reach the limits of both the students' and the academics' capacities to complete it. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):213-222, 2018.


Subject(s)
Beer/analysis , Biofuels/analysis , Educational Measurement , Laboratories , Problem-Based Learning , Research/education , Saccharomyces cerevisiae/metabolism , Humans , Students , Universities
6.
Biochem Mol Biol Educ ; 45(3): 235-248, 2017 05.
Article in English | MEDLINE | ID: mdl-28032403

ABSTRACT

Systems biology is frequently taught with an emphasis on mathematical modeling approaches. This focus effectively excludes most biology, biochemistry, and molecular biology students, who are not mathematics majors. The mathematical focus can also present a misleading picture of systems biology, which is a multi-disciplinary pursuit requiring collaboration between biochemists, bioinformaticians, and mathematicians. This article describes an authentic large-scale undergraduate research experience (ALURE) in systems biology that incorporates proteomics, bacterial genomics, and bioinformatics in the one exercise. This project is designed to engage students who have a basic grounding in protein chemistry and metabolism and no mathematical modeling skills. The pedagogy around the research experience is designed to help students attack complex datasets and use their emergent metabolic knowledge to make meaning from large amounts of raw data. On completing the ALURE, participants reported a significant increase in their confidence around analyzing large datasets, while the majority of the cohort reported good or great gains in a variety of skills including "analysing data for patterns" and "conducting database or internet searches." An environmental scan shows that this ALURE is the only undergraduate-level system-biology research project offered on a large-scale in Australia; this speaks to the perceived difficulty of implementing such an opportunity for students. We argue however, that based on the student feedback, allowing undergraduate students to complete a systems-biology project is both feasible and desirable, even if the students are not maths and computing majors. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):235-248, 2017.


Subject(s)
Biomedical Research , Computational Biology/education , Educational Measurement , Mathematics/education , Molecular Biology/education , Systems Biology/education , Australia , Curriculum , Genomics , Humans , Metabolomics , Proteomics , Universities
7.
Biochem Mol Biol Educ ; 45(3): 249-261, 2017 05.
Article in English | MEDLINE | ID: mdl-27925371

ABSTRACT

Evidence shows that science graduates often do not have the communication skills they need to meet workplace standards and expectations. One common mode of science communication is the poster. In a review of the literature we show that poster design is historically problematic, and that the guidance provided to students as they create posters for assessment is frequently inconsistent. To address this inconsistency we provide some guiding design principles for posters that are grounded in communication theory and the fundamentals of rhetoric. We also present three nondiscipline-specific example posters with accompanying notes that explain why the posters are examples of poor, average, and excellent poster design. The subject matter for the posters is a fabricated set of experiments on a topic that could not actually be the subject of research. Instructors may use these resources with their students, secure in the knowledge that they do not and will never represent an answer set to an extant assessment item. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):249-261, 2017.


Subject(s)
Audiovisual Aids , Biomedical Research , Communication , Learning , Multimedia , Science/education , Humans
8.
CBE Life Sci Educ ; 15(4)2016.
Article in English | MEDLINE | ID: mdl-27909029

ABSTRACT

The recent push for more authentic teaching and learning in science, technology, engineering, and mathematics indicates a shared agreement that undergraduates require greater exposure to professional practices. There is considerable variation, however, in how "authentic" science education is defined. In this paper we present our definition of authenticity as it applies to an "authentic" large-scale undergraduate research experience (ALURE); we also look to the literature and the student voice for alternate perceptions around this concept. A metareview of science education literature confirmed the inconsistency in definitions and application of the notion of authentic science education. An exploration of how authenticity was explained in 604 reflections from ALURE and traditional laboratory students revealed contrasting and surprising notions and experiences of authenticity. We consider the student experience in terms of alignment with 1) the intent of our designed curriculum and 2) the literature definitions of authentic science education. These findings contribute to the conversation surrounding authenticity in science education. They suggest two things: 1) educational experiences can have significant authenticity for the participants, even when there is no purposeful design for authentic practice, and 2) the continuing discussion of and design for authenticity in UREs may be redundant.


Subject(s)
Curriculum , Program Development , Research/education , Humans , Laboratories , Learning , Perception , Science/education , Students
9.
Front Aging Neurosci ; 8: 127, 2016.
Article in English | MEDLINE | ID: mdl-27303293

ABSTRACT

The primary cilia of forebrain neurons assemble around birth and become enriched with neuromodulatory receptors. Our understanding of the permanence of these structures and their associated signaling pathways in the aging brain is poor, but they are worthy of investigation because disruptions in neuronal cilia signaling have been implicated in changes in learning and memory, depression-like symptoms, and sleep anomalies. Here, we asked whether neurons in aged forebrain retain primary cilia and whether the staining characteristics of aged cilia for type 3 adenylyl cyclase (ACIII), somatostatin receptor 3 (SSTR3), and pericentrin resemble those of cilia in younger forebrain. To test this, we analyzed immunostained sections of forebrain tissues taken from young and aged male Fischer 344 (F344) and F344 × Brown Norway (F344 × BN) rats. Analyses of ACIII and SSTR3 in young and aged cortices of both strains of rats revealed that the staining patterns in the neocortex and hippocampus were comparable. Virtually every NeuN positive cell examined possessed an ACIII positive cilium. The lengths of ACIII positive cilia in neocortex were similar between young and aged for both strains, whereas in F344 × BN hippocampus, the cilia lengths increased with age in CA1 and CA3, but not in dentate gyrus (DG). Additionally, the percentages of ACIII positive cilia that were also SSTR3 positive did not differ between young and aged tissues in either strain. We also found that pericentrin, a protein that localizes to the basal bodies of neuronal cilia and functions in primary cilia assembly, persisted in aged cortical neurons of both rat strains. Collectively, our data show that neurons in aged rat forebrain possess primary cilia and that these cilia, like those present in younger brain, continue to localize ACIII, SSTR3, and pericentrin. Further studies will be required to determine if the function and signaling pathways regulated by cilia are similar in aged compared to young brain.

10.
Exp Neurol ; 282: 119-27, 2016 08.
Article in English | MEDLINE | ID: mdl-27181411

ABSTRACT

Neonatal or early-life seizures (ELS) are often associated with life-long neurophysiological, cognitive and behavioral deficits, but the underlying mechanisms contributing to these deficits remain poorly understood. Newborn, post-migratory cortical neurons sprout ciliary buds (procilia) that mature into primary cilia. Disruption of the growth or signaling capabilities of these cilia has been linked to atypical neurite outgrowth from neurons and abnormalities in neuronal circuitry. Here, we tested the hypothesis that generalized seizures induced by pentylenetetrazol (PTZ) or kainic acid (KA) during early postnatal development impair neuronal and/or glial ciliogenesis. Mice received PTZ (50 or 100mg/kg), KA (2mg/kg), or saline either once at birth (P0), or once daily from P0 to P4. Using immunohistochemistry and electron microscopy, the cilia of neurons and glia were examined at P7, P14, and P42. A total of 83 regions were analyzed, representing 13 unique neocortical and hippocampal regions. Neuronal cilia were identified by co-expression of NeuN and type 3 adenylyl cyclase (ACIII) or somatostatin receptor 3 (SSTR3), while glial cilia were identified by co-expression of GFAP, Arl13b, and gamma-tubulin. We found that PTZ exposure at either P0 or from P0 to P4 induced convulsive behavior, followed by acute and lasting effects on neuronal cilia lengths that varied depending on the cortical region, PTZ dose, injection frequency, and time post-PTZ. Both increases and decreases in neuronal cilia length were observed. No changes in the length of glial cilia were observed under any of the test conditions. Lastly, we found that a single KA seizure at P0 led to similar abnormalities in neuronal cilia lengths. Our results suggest that seizure(s) occurring during early stages of cortical development induce persistent and widespread changes in neuronal cilia length. Given the impact neuronal cilia have on neuronal differentiation, ELS-induced changes in ciliogenesis may contribute to long-term pathology and abnormal cortical function.


Subject(s)
Cerebral Cortex , Convulsants/toxicity , Kainic Acid/toxicity , Neuroglia/drug effects , Neurons/drug effects , Pentylenetetrazole/toxicity , Seizures/chemically induced , Age Factors , Animals , Animals, Newborn , Cerebral Cortex/drug effects , Cerebral Cortex/growth & development , Cerebral Cortex/pathology , Disease Models, Animal , Dose-Response Relationship, Drug , Female , Mice , Microscopy, Immunoelectron , Nerve Tissue Proteins/metabolism , Neuroglia/physiology , Neuroglia/ultrastructure , Neurons/metabolism , Neurons/ultrastructure , Seizures/pathology
11.
Oncotarget ; 7(6): 7029-43, 2016 Feb 09.
Article in English | MEDLINE | ID: mdl-26760767

ABSTRACT

KIF3A, a component of the kinesin-2 motor, is necessary for the progression of diverse tumor types. This is partly due to its role in regulating ciliogenesis and cell responsiveness to sonic hedgehog (SHH). Notably, primary cilia have been detected in human glioblastoma multiforme (GBM) tumor biopsies and derived cell lines. Here, we asked whether disrupting KIF3A in GBM cells affected ciliogenesis, in vitro growth and responsiveness to SHH, or tumorigenic behavior in vivo. We used a lentiviral vector to create three patient-derived GBM cell lines expressing a dominant negative, motorless form of Kif3a (dnKif3a). In all unmodified lines, we found that most GBM cells were capable of producing ciliated progeny and that dnKif3a expression in these cells ablated ciliogenesis. Interestingly, unmodified and dnKif3a-expressing cell lines displayed differential sensitivities and pathway activation to SHH and variable tumor-associated survival following mouse xenografts. In one cell line, SHH-induced cell proliferation was prevented in vitro by either expressing dnKif3a or inhibiting SMO signaling using cyclopamine, and the survival times of mice implanted with dnKif3a-expressing cells were increased. In a second line, expression of dnKif3a increased the cells' baseline proliferation while, surprisingly, sensitizing them to SHH-induced cell death. The survival times of mice implanted with these dnKif3a-expressing cells were decreased. Finally, expression of dnKif3a in a third cell line had no effect on cell proliferation, SHH sensitivity, or mouse survival times. These findings indicate that KIF3A is essential for GBM cell ciliogenesis, but its role in modulating GBM cell behavior is highly variable.


Subject(s)
Carcinogenesis/pathology , Cilia/physiology , Genes, Dominant/genetics , Glioblastoma/pathology , Hedgehog Proteins/metabolism , Kinesins/antagonists & inhibitors , Adult , Aged , Animals , Apoptosis , Blotting, Western , Carcinogenesis/genetics , Carcinogenesis/metabolism , Cell Proliferation , Glioblastoma/genetics , Glioblastoma/metabolism , Hedgehog Proteins/genetics , Humans , Immunoenzyme Techniques , Kinesins/genetics , Male , Mice , Mice, Inbred NOD , Mice, SCID , Middle Aged , Signal Transduction , Tumor Cells, Cultured , Xenograft Model Antitumor Assays
12.
Biochem Mol Biol Educ ; 42(1): 6-14, 2014.
Article in English | MEDLINE | ID: mdl-24591041

ABSTRACT

SoTL stands for the Scholarship of Teaching and Learning. The acronym, said "sottle" or "sote-all," describes research that involves rigorous examination of teaching and learning by faculty who are actively involved in the educational process. The number of natural-science faculty engaged in SoTL is increasing, and their important work has broad implications for the measurement and improvement of college teaching and learning outcomes. The data show, however, that many faculty who conduct SoTL projects in science departments begin their education research careers with no training in SoTL research methodologies, and find they are working alone, with few colleagues who can nurture (or even understand) their efforts. In this article we provide a guide intended to help natural-science faculty initiate SoTL projects while they negotiate the mechanics and politics of developing and maintaining a SoTL research program in a science department.


Subject(s)
Education, Professional/methods , Fellowships and Scholarships , Learning , Natural Science Disciplines/education , Problem-Based Learning/methods , Humans
13.
CBE Life Sci Educ ; 13(1): 29-40, 2014.
Article in English | MEDLINE | ID: mdl-24591501

ABSTRACT

The Course-Based Undergraduate Research Experiences Network (CUREnet) was initiated in 2012 with funding from the National Science Foundation program for Research Coordination Networks in Undergraduate Biology Education. CUREnet aims to address topics, problems, and opportunities inherent to integrating research experiences into undergraduate courses. During CUREnet meetings and discussions, it became apparent that there is need for a clear definition of what constitutes a CURE and systematic exploration of what makes CUREs meaningful in terms of student learning. Thus, we assembled a small working group of people with expertise in CURE instruction and assessment to: 1) draft an operational definition of a CURE, with the aim of defining what makes a laboratory course or project a "research experience"; 2) summarize research on CUREs, as well as findings from studies of undergraduate research internships that would be useful for thinking about how students are influenced by participating in CUREs; and 3) identify areas of greatest need with respect to CURE assessment, and directions for future research on and evaluation of CUREs. This report summarizes the outcomes and recommendations of this meeting.


Subject(s)
Curriculum , Educational Measurement , Research/education , Universities , Humans , Models, Educational , Students
14.
J Neurooncol ; 117(1): 15-24, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24510433

ABSTRACT

Glioblastoma (GBM) is the most common malignant adult brain tumor and carries a poor prognosis due to primary and acquired resistance. While many cellular features of GBM have been documented, it is unclear if cells within these tumors extend a primary cilium, an organelle whose associated signaling pathways may regulate proliferation, migration, and survival of neural precursor and tumor cells. Using immunohistochemical and electron microscopy (EM) techniques, we screened human GBM tumor biopsies and primary cell lines for cilia. Immunocytochemical staining of five primary GBM cell lines revealed that between 8 and 25 % of the cells in each line possessed gamma tubulin-positive basal bodies from which extended acetylated, alpha-tubulin-positive axonemes. EM analyses confirmed the presence of cilia at the cell surface and revealed that their axonemes contained organized networks of microtubules, a structural feature consistent with our detection of IFT88 and Arl13b, two trafficked cilia proteins, along the lengths of the axonemes. Notably, cilia were detected in each of 23 tumor biopsies (22 primary and 1 recurrent) examined. These cilia were distributed across the tumor landscape including regions proximal to the vasculature and within necrotic areas. Moreover, ciliated cells within these tumors co-stained with Ki67, a marker for actively dividing cells, and ZEB1, a transcription factor that is upregulated in GBM and linked to tumor initiation, invasion, and chemoresistance. Collectively, our data show that subpopulations of cells within human GBM tumors are ciliated. In view of mounting evidence supporting roles of primary cilia in tumor initiation and propagation, it is likely that further study of the effects of cilia on GBM tumor cell function will improve our understanding of GBM pathogenesis and may provide new directions for GBM treatment strategies.


Subject(s)
Brain Neoplasms/metabolism , Brain Neoplasms/ultrastructure , Cilia/ultrastructure , Glioblastoma/metabolism , Glioblastoma/ultrastructure , ADP-Ribosylation Factors/metabolism , Aged, 80 and over , Axoneme/metabolism , Axoneme/ultrastructure , Basal Bodies/metabolism , Basal Bodies/ultrastructure , Cell Line, Tumor , Cilia/metabolism , Homeodomain Proteins/metabolism , Humans , Immunohistochemistry , Ki-67 Antigen/metabolism , Male , Microscopy, Electron , Middle Aged , Transcription Factors/metabolism , Tubulin/metabolism , Tumor Suppressor Proteins/metabolism , Zinc Finger E-box-Binding Homeobox 1
15.
Methods ; 66(3): 466-73, 2014 Apr 01.
Article in English | MEDLINE | ID: mdl-23816789

ABSTRACT

The abilities of lentiviral vectors to carry large transgenes (∼8kb) and to efficiently infect and integrate these genes into the genomes of both dividing and non-dividing cells make them ideal candidates for transport of genetic material into cells and tissues. Given the properties of these vectors, it is somewhat surprising that they have seen only limited use in studies of developing tissues and in particular of the developing nervous system. Over the past several years, we have taken advantage of the large capacity of these vectors to explore the expression characteristics of several dual promoter and 2A peptide bicistronic transgenes in developing chick neural retina, with the goal of identifying transgene designs that reliably express multiple proteins in infected cells. Here we summarize the activities of several of these transgenes in neural retina and provide detailed methodologies for packaging lentivirus and delivering the virus into the developing neural tubes of chicken embryos in ovo, procedures that have been optimized over the course of several years of use in our laboratory. Conditions to hatch injected embryos are also discussed. The chicken-specific techniques will be of highest interest to investigators using avian embryos, development and packaging of lentiviral vectors that reliably express multiple proteins in infected cells should be of interest to all investigators whose experiments demand manipulation and expression of multiple proteins in developing cells and tissues.


Subject(s)
Embryonic Development/genetics , Genetic Engineering/methods , Genetic Vectors , Lentivirus/genetics , Transgenes , Animals , Animals, Genetically Modified/genetics , Chick Embryo , Retina/embryology
16.
J Bacteriol ; 195(10): 2349-58, 2013 May.
Article in English | MEDLINE | ID: mdl-23504013

ABSTRACT

Histidine kinases are sophisticated molecular sensors that are used by bacteria to detect and respond to a multitude of environmental signals. KinA is the major histidine kinase required for initiation of sporulation upon nutrient deprivation in Bacillus subtilis. KinA has a large N-terminal region (residues 1 to 382) that is uniquely composed of three tandem Per-ARNT-Sim (PAS) domains that have been proposed to constitute a sensor module. To further enhance our understanding of this "sensor" region, we defined the boundaries that give rise to the minimal autonomously folded PAS domains and analyzed their homo- and heteroassociation properties using analytical ultracentrifugation, nuclear magnetic resonance (NMR) spectroscopy, and multiangle laser light scattering. We show that PAS(A) self-associates very weakly, while PAS(C) is primarily a monomer. In contrast, PAS(B) forms a stable dimer (K(d) [dissociation constant] of <10 nM), and it appears to be the main N-terminal determinant of KinA dimerization. Analysis of KinA mutants deficient for one or more PAS domains revealed a critical role for PAS(B), but not PAS(A), in autophosphorylation of KinA. Our findings suggest that dimerization of PAS(B) is important for keeping the catalytic domain of KinA in a functional conformation. We use this information to propose a model for the structure of the N-terminal sensor module of KinA.


Subject(s)
Bacillus subtilis/enzymology , Bacterial Proteins/metabolism , Protein Kinases/metabolism , Bacillus subtilis/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial , Magnetic Resonance Spectroscopy , Protein Kinases/chemistry , Protein Kinases/genetics , Protein Multimerization/genetics , Protein Multimerization/physiology , Protein Structure, Tertiary/genetics , Protein Structure, Tertiary/physiology , Ultracentrifugation
17.
J Neurosci ; 33(6): 2626-38, 2013 Feb 06.
Article in English | MEDLINE | ID: mdl-23392690

ABSTRACT

The formation of primary cilia is a highly choreographed process that can be disrupted in developing neurons by overexpressing neuromodulatory G-protein-coupled receptors GPCRs or by blocking intraflagellar transport. Here, we examined the effects of overexpressing the ciliary GPCRs, 5HT6 and SSTR3, on cilia structure and the differentiation of neocortical neurons. Neuronal overexpression of 5HT6 and SSTR3 was achieved by electroporating mouse embryo cortex in utero with vectors encoding these receptors. We found that overexpression of ciliary GPCRs in cortical neurons, especially 5HT6, induced the formation of long (>30 µm) and often forked cilia. These changes were associated with increased levels of intraflagellar transport proteins and accelerated ciliogenesis in neonatal neocortex, the induction of which required Kif3a, an anterograde motor critical for cilia protein trafficking and growth. GPCR overexpression also altered the complement of signaling molecules within the cilia. We found that SSTR3 and type III adenylyl cyclase (ACIII), proteins normally enriched in neuronal cilia, were rarely detected in 5HT6-elongated cilia. Intriguingly, the changes in cilia structure were accompanied by changes in neuronal morphology. Specifically, disruption of normal ciliogenesis in developing neocortical neurons, either by overexpressing cilia GPCRs or a dominant-negative form of Kif3a, significantly impaired dendrite outgrowth. Remarkably, coexpression of ACIII with 5HT6 restored ACIII to cilia, normalized cilia structure, and restored dendrite outgrowth, effects that were not observed in neurons coexpressing ACIII and dominant-negative form of Kif3a. Collectively, our data suggest the formation of neuronal dendrites in developing neocortex requires structurally normal cilia enriched with ACIII.


Subject(s)
Adenylyl Cyclases/physiology , Cilia/enzymology , Dendrites/enzymology , Neocortex/enzymology , Neurons/enzymology , Receptors, Serotonin/biosynthesis , Animals , Cells, Cultured , Cilia/physiology , Female , Kinesins/biosynthesis , Male , Mice , NIH 3T3 Cells , Neocortex/embryology , Neurogenesis/physiology , Neurons/cytology , Pregnancy
18.
J Neurosci ; 33(6): 2671-83, 2013 Feb 06.
Article in English | MEDLINE | ID: mdl-23392694

ABSTRACT

The expression of the ERα and ERß estrogen receptors in the hippocampus may be important in the etiology of age-related cognitive decline. To examine the role of ERα and ERß in regulating transcription and learning, ovariectomized wild-type (WT) and ERα and ERß knockout (KO) mice were used. Hippocampal gene transcription in young ERαKO mice was similar to WT mice 6 h after a single estradiol treatment. In middle-age ERαKO mice, hormone deprivation was associated with a decrease in the expression of select genes associated with the blood-brain barrier; cyclic estradiol treatment increased transcription of these select genes and improved learning in these mice. In contrast to ERαKO mice, ERßKO mice exhibited a basal hippocampal gene profile similar to WT mice treated with estradiol and, in the absence of estradiol treatment, young and middle-age ERßKO mice exhibited preserved learning on the water maze. The preserved memory performance of middle-age ERßKO mice could be reversed by lentiviral delivery of ERß to the hippocampus. These results suggest that one function of ERß is to regulate ERα-mediated transcription in the hippocampus. This model is supported by our observations that knockout of ERß under conditions of low estradiol allowed ERα-mediated transcription. As estradiol levels increased in the absence of ERα, we observed that other mechanisms, likely including ERß, regulated transcription and maintained hippocampal-dependent memory. Thus, our results indicate that ERα and ERß interact with hormone levels to regulate transcription involved in maintaining hippocampal function during aging.


Subject(s)
Aging/physiology , Estrogen Receptor alpha/physiology , Estrogen Receptor beta/physiology , Hippocampus/physiology , Animals , Female , Maze Learning/physiology , Mice , Mice, Knockout
19.
PLoS One ; 8(12): e83378, 2013.
Article in English | MEDLINE | ID: mdl-24386190

ABSTRACT

Many aspects of retinal photoreceptor function and physiology are regulated by the circadian clocks in these cells. It is well established that light is the primary stimulus that entrains these clocks; yet, the biochemical cascade(s) mediating light's effects on these clocks remains unknown. This deficiency represents a significant gap in our fundamental understanding of photoreceptor signaling cascades and their functions. In this study, we utilized re-aggregated spheroid cultures prepared from embryonic chick retina to determine if activation of phospholipase C in photoreceptors in the absence of light can phase shift the melatonin secretion rhythms of these cells in a manner similar to that induced by light. We show that spheroid cultures rhythmically secrete melatonin and that these melatonin rhythms can be dynamically phase shifted by exposing the cultures to an appropriately timed light pulse. Importantly, we show that activation of phospholipase C using m-3M3FBS in the absence of light induces a phase delay in photoreceptor melatonin rhythms that mirrors that induced by light. The implication of this finding is that the light signaling cascade that entrains photoreceptor melatonin rhythms involves activation of phospholipase C.


Subject(s)
Circadian Rhythm/physiology , Light , Melatonin/metabolism , Photoreceptor Cells, Vertebrate/metabolism , Type C Phospholipases/metabolism , Animals , Chick Embryo , Enzyme Activation , Tissue Culture Techniques
20.
PLoS One ; 7(12): e51385, 2012.
Article in English | MEDLINE | ID: mdl-23240018

ABSTRACT

We previously demonstrated that aged ovariectomized rats that had received prior estradiol treatment in middle-age exhibited increased levels of estrogen receptor alpha (ERα) in the hippocampus as well as enhanced hippocampal dependent memory as compared to aged rats that had not received mid-life estradiol treatment. These effects persisted long after the estradiol treatment had been terminated. The goal of the current experiment was to determine if increased expression of ERα in the hippocampus, in the absence of exogenously administered estrogens, can impact the hippocampus and cognitive function in aging ovariectomized rats. Middle-aged rats were trained for 24 days on an eight-arm radial maze spatial memory task. All rats were then ovariectomized. Forty days later, rats received either lentiviral delivery to the hippocampus of the gene encoding ERα (lenti-ERα) or a control virus. Rats were tested on delay trials in the radial-maze in which delays of varying lengths were imposed between the fourth and fifth arm choices. Following behavior testing, hippocampi were immunostained using western blotting for ERα, the ERα-regulated protein choline acetyltransferase, and phosphorylation of the ERα-regulated kinases, ERK/MAPK and Akt. Results revealed that aging ovariectomized rats that received delivery of lenti-ERα to the hippocampus exhibited enhanced spatial memory as indicated by increased arm-choice accuracy across delays as compared to ovariectomized rats that received control virus. Western blot data revealed that lenti-ERα delivery significantly increased levels of ERα and phosphorylated ERK/MAPK and had no impact on levels of ChAT or phosphorylation of Akt. Results indicate that increasing hippocampal levels of ERα in aging females in the absence of ovarian or exogenously administered estrogens leads to increases in phosphorylation of ERK/MAPK as well as in enhanced memory.


Subject(s)
Aging , Estrogen Receptor alpha , Memory , Aging/genetics , Aging/metabolism , Animals , Estrogen Receptor alpha/genetics , Estrogen Receptor alpha/metabolism , Genetic Vectors , Hippocampus/metabolism , Maze Learning , Memory/drug effects , Memory/physiology , Mitogen-Activated Protein Kinases/metabolism , Ovariectomy , Rats
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