The mammalian olfactory system has developed some functionality by the time of birth. There is behavioral and limited electrophysiological evidence for prenatal olfaction in various mammalian species. However, there have been no reports, in any mammalian species, of recordings from prenatal olfactory sensory neurons (OSNs) that express a given odorant receptor (OR) gene. Here we have performed patch-clamp recordings from mouse OSNs that express the OR gene S1 or MOR23, using the odorous ligands 2-phenylethyl alcohol or lyral, respectively. We found that, out of a combined total of 20 OSNs from embryos of these two strains at embryonic day (E)16.5 or later, all responded to a cognate odorous ligand. By contrast, none of six OSNs responded to the ligand at E14.5 or E15.5. The kinetics of the odorant-evoked electrophysiological responses of prenatal OSNs are similar to those of postnatal OSNs. The S1 and MOR23 glomeruli in the olfactory bulb are formed postnatally, but the axon terminals of OSNs expressing these OR genes may be synaptically active in the olfactory bulb at embryonic stages. The upper limit of the acquisition of odorant responsiveness for S1 and MOR23 OSNs at E16.5 is consistent with the developmental expression patterns of components of the olfactory signaling pathway.
Voltage-gated Kv1.5 channels are expressed in a wide variety of tissues including cardiac myocytes, smooth muscle and tumor cells. Kv1.5 channel activity is modified by N-cadherin, which in turn binds the multifunctional oncogenic protein ?-catenin. The present experiments explored the effect of ?-catenin on Kv1.5 channel activity. To this end, Kv1.5 was expressed in Xenopus oocytes with or without ?-catenin and the voltage-gated Kv current determined by dual electrode voltage clamp. As a result, expression of ?-catenin significantly increased the voltage-gated Kv current at positive potentials. The stimulating effect of ?-catenin on Kv1.5 was not dependent on the stimulation of transcription since it was observed even in the presence of the transcription inhibitor actinomycin D. Specific antibody binding to surface Kv1.5 in Xenopus oocytes revealed that ?-catenin enhances the membrane abundance of Kv1.5. Further experiments with brefeldin A showed that ?-catenin fosters the insertion of Kv1.5 into rather than delaying the retrieval from the plasma membrane. According to electrophysiological recordings with mutant ?-catenin, the effect on Kv1.5 requires the same protein domains that are required for association of ?-catenin with cadherin. The experiments disclose a completely novel function of ?-catenin, i.e. the regulation of Kv1.5 channel activity.
As early as 2001, the Food and Drug Administration (FDA) required blood centers and hospital transfusion services to report events associated with testing, storage, or distribution of blood products that deviated from current good manufacturing practices or affected the safety, purity, or potency of the product. Between 2004 and 2009, an average of only 8.6% of hospitals reported blood product deviations.
This study investigates correlates of Hong Kong Chinese adolescents identity statuses with (i) parental and school contexts and (ii) major psychosocial developmental outcomes. Data were collected from 1260 Secondary 2-4 (equivalent to Grades 8-10 in the US school system) students through a questionnaire survey. Results of hierarchical regression analysis indicated that parental attributes of acceptance, values and goals, and psychological control, and school contextual factor of task orientations predicted identity achievement, whereas parents acceptance, psychological and firm control, and teachers support predicted identity foreclosure. Regarding the impact on psychosocial development, another series of regression analyses revealed that (i) identity achievement predicted low depression, high self-esteem, and high self-efficacy; (ii) moratorium predicted low self-esteem; and (iii) foreclosure predicted high self-efficacy. Overall, the findings shed light on adolescent identity development in Hong Kong, facilitating discussions on identity-related issues.
?-Catenin is a multifunctional protein stimulating as oncogenic transcription factor several genes important for cell proliferation. ?-Catenin-regulated genes include the serum- and glucocorticoid-inducible kinase SGK1, which is known to stimulate a variety of transport systems. The present study explored the possibility that ?-catenin influences membrane transport. To this end, ?-catenin was expressed in Xenopus oocytes with or without SGLT1 and electrogenic transport determined by dual electrode voltage clamp. As a result, expression of ?-catenin significantly enhanced the ouabain-sensitive current of the endogeneous Na(+)/K(+)-ATPase. Inhibition of vesicle trafficking by brefeldin A revealed that the stimulatory effect of ?-catenin on the endogenous Na(+)/K(+)-ATPase was not due to enhanced stability of the pump protein in the cell membrane. Expression of ?-catenin further enhanced glucose-induced current (Ig) in SGLT1-expressing oocytes. In the absence of SGLT1 Ig was negligible irrespective of ?-catenin expression. The stimulating effect of ?-catenin on both Na(+)/K(+) ATPase and SGLT1 activity was observed even in the presence of actinomycin D, an inhibitor of transcription. The experiments disclose a completely novel function of ?-catenin, i.e. the regulation of transport.
The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated Cl(-) channel critically important in Cl(-) secreting epithelia. Mutations in the CFTR gene, such as (DeltaF508)CFTR leads to cystic fibrosis, a severe disease with defective Cl(-) secretion. CFTR is stimulated by the serum and glucocorticoid-inducible kinase SGK1. The SGK1 dependent regulation of several carriers and channels involves the phosphatidylinositol-3-phosphate-5-kinase PIKfyve, which similarly mediates the regulation of glucose carriers by PKB/Akt. The present study was thus performed to elucidate whether PKB/Akt and PIKfyve are regulators of CFTR. To this end CFTR or (DeltaF508)CFTR were expressed in Xenopus oocytes alone or together with PKB, PIKfyve or the SGK1/PKB resistant mutant (S318A)PIKfyve, and the current generated by cAMP upregulation with 10muM forskolin+1mM IBMX determined utilizing dual electrode voltage clamp. As a result, forskolin/IBMX treatment triggered a current (I(cAMP)) in CFTR-expressing Xenopus oocytes, but not in oocytes expressing (DeltaF508)CFTR. Coexpression of PKB/Akt and PIKfyve, but not of (S318A)PIKfyve, stimulated I(cAMP) in CFTR-expressing ( approximately 2- to 3-fold) but not in (DeltaF508)CFTR-expressing or water injected Xenopus oocytes. Immunohistochemistry revealed that the coexpression of PIKfyve, but not of (S318A)PIKfyve, enhanced the CFTR protein abundance but not the (DeltaF508)CFTR protein abundance in CFTR or (DeltaF508)CFTR-expressing oocytes. The present observations reveal a novel powerful regulator of intact but not of defective CFTR.
The PI3K pathway plays a pivotal role in the stimulation of mast cells. PI3K-dependent kinases include the serum- and glucocorticoid-inducible kinase 1 (SGK1). The present study explored the role of SGK1 in mast cell function. Mast cells were isolated from bone marrow (BMMC) of SGK1 knockout mice (sgk1(-/-)) and their wild-type littermates (sgk1(+/+)). The BMMC number as well as CD117, CD34, and FcepsilonRI expression in BMCCs were similar in both genotypes. Upon Ag stimulation of the FcepsilonRI receptor, Ca(2+) entry but not Ca(2+) release from intracellular stores was markedly impaired in sgk1(-/-) BMMCs. The currents through Ca(2+)-activated K+ channels induced by Ag were significantly higher in sgk1(+/+) BMMCs than in sgk1(-/-) BMMCs. Treatment with the Ca(2+) ionophore ionomycin (1 microM) led to activation of the K+ channels in both genotypes, indicating that the Ca(2+)-activated K+ channels are similarly expressed and sensitive to activation by Ca(2+) in sgk1(+/+) and sgk1(-/-) BMMCs, and that blunted stimulation of Ca(2+)-activated K+ channels was secondary to decreased Ca(2+) entry. Ag-IgE-induced degranulation and early IL-6 secretion were also significantly blunted in sgk1(-/-) BMMCs. The decrease in body temperature following Ag treatment, which reflects an anaphylactic reaction, was substantially reduced in sgk1(-/-) mice, pointing to impaired mast cell function in vivo. Serum histamine levels measured 30 min after induction of an anaphylactic reaction were significantly lower in sgk1(-/-) than in sgk1(+/+)mice. The observations reveal a critical role for SGK1 in ion channel regulation and the function of mast cells, and thus disclose a completely novel player in the regulation of allergic reaction.
Pulmonary infection caused by the opportunistic organisms Penicillium marneffei and Stenotrophomonas maltophilia in patients with Jobs syndrome is rare and not well documented. The case of a 30-year-old man with Jobs syndrome who developed recurrent pneumonia and lung abscesses caused by P. marneffei and S. maltophilia, complicated by massive hemoptysis, is described. Bronchial artery embolization was successful in controlling the hemoptysis; however, the infection proved fatal despite appropriate antimicrobial therapy. A brief review of the literature on Jobs syndrome and its associated infective pulmonary manifestations is also presented.
Cholesterol affects diverse biological processes, in many cases by modulating the function of integral membrane proteins. In this study we have investigated the role of cholesterol in the adenosine-dependent regulation of ion transport in colonic epithelial cells. We observed that methyl-beta-cyclodextrin (MbetaCD), a cholesterol-sequestering molecule, enhanced adenosine A(2A) receptor-activated transepithelial short circuit current (I(sc)), but only from the basolateral side. Cholesterol is a major constituent of membrane microdomains, called lipid rafts that also contain sphingolipids. However, studies with the sphingomyelin-degrading enzyme, sphingomyelinase, and the cholesterol-binding agent, filipin, indicated that the change in the level of cholesterol alone was sufficient to control the adenosine-modulated I(sc). Cholesterol depletion had a major effect on the functional selectivity of A(2A) receptors. Under control conditions, adenosine activated I(sc) more potently than the specific A(2A) agonist, CGS-21680, and the current was inhibited by XE991, an inhibitor of cAMP-dependent K(+) channels. Following cholesterol depletion, CGS-21680 activated I(sc) more potently than adenosine, and the current was inhibited by clotrimazole, an inhibitor of Ca(2+)-activated K(+) (IK1) channels. Co-immunoprecipitation experiments revealed that A(2A) receptors associate with IK1 channels following cholesterol depletion. These results suggest that cholesterol content in colonic epithelia affects adenosine-mediated anion secretion by controlling agonist-selective signaling.
Eye movements in Sally-Anne false-belief tasks appear to reflect the ability to implicitly monitor the mental states of other individuals (theory of mind, or ToM). It has recently been proposed that an early-developing, efficient, and automatically operating ToM system subserves this ability. Surprisingly absent from the literature, however, is an empirical test of the influence of domain-general executive processing resources on this implicit ToM system. In the study reported here, a dual-task method was employed to investigate the impact of executive load on eye movements in an implicit Sally-Anne false-belief task. Under no-load conditions, adult participants displayed eye movement behavior consistent with implicit belief processing, whereas evidence for belief processing was absent for participants under cognitive load. These findings indicate that the cognitive system responsible for implicitly tracking beliefs draws at least minimally on executive processing resources. Thus, even the most low-level processing of beliefs appears to reflect a capacity-limited operation.
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