An electric circuit for plant protoplast manipulation is described. The circuit used readily available materials and was designed for use in teaching. This integrated circuit can be placed in a ...single small box with controls for the aligning voltage, the aligning frequency, the pulse voltage, and the pulse timing. The circuit can be supplied by any suitable source of dc power and can be easily altered for individual requirements. The circuit, as presented here, can be assembled for less than $250.
Electrically excitable channels were expressed in Chinese hamster ovary cells using a vaccinia virus vector system. In cells expressing rat brain IIA Na$\sp+$ channels, brief pulses ($<$1 ms) of ...depolarizing current resulted in action potentials with a prolonged (0.5-3 s) depolarizing plateau; this plateau was caused by slow and incomplete Na$\sp+$ channel inactivation. In cells expressing both Na$\sp+$ and Drosophila Shaker H4 transient K$\sp+$ channels, there were neuron-like action potentials. In cells with appropriate Na$\sp+$/K$\sp+$ current ratios, maintained stimulation produced repetitive firing over a 10-fold range of frequencies but eventually led to "lockup" of the potential at a positive value after several seconds of stimulation; the latter effect was due primarily to slow inactivation of the K$\sp+$ currents. Numerical simulations of modified Hodgkin-Huxley equations describing these currents, using parameters from voltage-clamp kinetics studied in the same cells, accounted for most features of the voltage trajectories. The present study shows that insights into the mechanisms for generating action potentials and trains of action potentials in real excitable cells can be obtained from the analysis of synthetic excitable cells that express a controlled repertoire of ion channels. This model system provides a direct control of complexity of neuronal behavior, and a tool for studying various forms of neural modulation at molecular and cellular levels.
Lewis rats which have Ir-EAE gene develop EAE after challenge with either GPBP or GPEF, a 42-residue fragment. BN rats which lack the Ir gene do not develop EAE after challenge with these proteins. ...The immune response against GPEF was compared in these two strains of rats. It was found that Le rats produce small amounts of antibody and a cell-mediated immune response against GPEF; in contrast BN rats did neither. These findings support the concept that the Ir-EAE gene exerts its effect by controlling the immune response against GPEF.
This work studies the syntactic behavior of NP-traces in Chinese. NP-Movement in Chinese is first examined descriptively within the Transformational Grammar (TG) framework in regard to constraints on ...these rules. A result of these discussions is the claim that Chinese like English has NP-traces. Several aspects of NP-traces are then explored within the Government and Binding (GB) framework. The effects of government, case-marking and $\theta$-role assignment are observed. Also, the Empty Category Principle is found to be adequate to capture the behavior of NP-traces in Chinese under proper government. Finally, the principles of Binding theory are shown to account for the anaphoric relation between an NP-trace and its antecedent. However, the theory doesn't make predictions about the A$\sp\prime$-bound NP-traces in Chinese. However, the Generalized Binding Theory may offer a solution. This study further implies that the TG or GB framework applies to isolating languages like Chinese.
Abstract
Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer that rarely develops de novo in primary tumors and is commonly acquired during the development of treatment ...resistance. NEPC is characterized by gain of neuroendocrine markers and loss of androgen receptor (AR), making it resistant to current therapeutic strategies targeting the AR signaling axis. Here, we report that MCM2, MCM3, MCM4, and MCM6 (MCM2/3/4/6) are elevated in human NEPC and high levels of MCM2/3/4/6 are associated with liver metastasis and poor survival in prostate cancer patients. MCM2/3/4/6 are four out of six proteins that form a core DNA helicase (MCM2-7) responsible for unwinding DNA forks during DNA replication. Inhibition of MCM2-7 by treatment with ciprofloxacin inhibits NEPC cell proliferation and migration in vitro, significantly delays NEPC tumor xenograft growth, and partially reverses the neuroendocrine phenotype in vivo. Our study reveals the clinical relevance of MCM2/3/4/6 proteins in NEPC and suggests that inhibition of MCM2-7 may represent a new therapeutic strategy for NEPC.
While extant literature generally suggests a positive relationship between entrepreneurial self-efficacy and entrepreneurial intention, several moderators have been identified – suggesting possible ...boundary conditions on that relationship. This paper introduces perceived person-entrepreneurship fit to entrepreneurship and shows that it moderates the relationship between entrepreneurial self-efficacy and entrepreneurial intention. Three studies are conducted which illuminate the utility of randomized experiments and methodological approaches to address limitations in the interpretation of empirical results. Studies 1 and 2 are randomized experiments to examine causality; Study 3 contains two correlational surveys to triangulate the results by examining whether the proposed effects withstand the influence of confounding variables in real-life. The findings indicate that when a strong perception of fit with entrepreneurship is achieved, entrepreneurial intention is strongly predicted by entrepreneurial self-efficacy. In contrast, if one perceives a low level of fit or no fit, entrepreneurial intention will be low, regardless of entrepreneurial self-efficacy.
•Perceived P-ENT fit increases entrepreneurial intentions.•Entrepreneurial self-efficacy increases entrepreneurial intentions.•Perceived P-ENT fit positively moderates the relationship between entrepreneurial self-efficacy and entrepreneurial intention.
Designing Entrepreneurship Experiments Hsu, Dan K.; Simmons, Sharon A.; Wieland, Alice M.
Organizational research methods,
07/2017, Letnik:
20, Številka:
3
Journal Article
Recenzirano
This article discusses the current and potential application of experimental methods to the study of entrepreneurship phenomena. Drawing on a review of experimental studies in entrepreneurship ...research, we discuss the advantages and disadvantages of experimental research designs for entrepreneurship research as a primer for those interested but not overly familiar with these methods. To advance research agendas and theory in the field, we introduce a typology of experimental manipulations that highlight alternative design choices based on the nature of their participant impact and realism of context. Finally, we provide an overview of areas of opportunity within the entrepreneurship literature for application of methods best suited to provide greater insight into the causal mechanisms at play.
Jasmonates are a family of plant hormones that regulate plant growth, development and responses to stress. The F-box protein CORONATINE INSENSITIVE 1 (COI1) mediates jasmonate signalling by promoting ...hormone-dependent ubiquitylation and degradation of transcriptional repressor JAZ proteins. Despite its importance, the mechanism of jasmonate perception remains unclear. Here we present structural and pharmacological data to show that the true Arabidopsis jasmonate receptor is a complex of both COI1 and JAZ. COI1 contains an open pocket that recognizes the bioactive hormone (3R,7S)-jasmonoyl-l-isoleucine (JA-Ile) with high specificity. High-affinity hormone binding requires a bipartite JAZ degron sequence consisting of a conserved α-helix for COI1 docking and a loop region to trap the hormone in its binding pocket. In addition, we identify a third critical component of the jasmonate co-receptor complex, inositol pentakisphosphate, which interacts with both COI1 and JAZ adjacent to the ligand. Our results unravel the mechanism of jasmonate perception and highlight the ability of F-box proteins to evolve as multi-component signalling hubs.
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