PCK1 expression is correlated with the plasma glucose level in the duck

Phosphoenolpyruvate carboxykinase 1 (soluble) (PCK1) is a key gene in gluconeogenesis and glyceroneogenesis. Although its functions have been extensively studied in mice, bats and humans, little is known in ducks. Here, PCK1 functions were studied using a duck domestication model and a 48-h fasting experiment. We found PCK1 expression significantly decreased in two breeds of domestic ducks (Jinyun Pockmark ducks and Cherry Valley ducks) as compared with wild ducks (Anas platyrhynchos). Simultaneously, plasma levels of glucose, triglycerides and free fatty acid in domestic ducks were lower than in wild ducks. When compared with fed ducks, the plasma triglyceride level was observed to be significantly decreased, while the glucose and free fatty acid levels remained constant in 48-h fasting ducks. The expression analysis of gluconeogenic genes revealed that fructose-1,6-bisphosphatase genes (FBP1 and FBP2) and the glucose-6-phosphatase gene (G6PC2) were not changed, whereas PCK1 was significantly upregulated. In addition, the reported regulators of PCK1, including forkhead box A2 (FOXA2) gene and orphan nuclear receptor NR4A family genes (NR4A1, NR4A2 and NR4A3), exhibited similar expression levels between 48-h fasting ducks and fed ducks, suggesting that PCK1 is not regulated by these genes in the duck under fasting conditions. In conclusion, PCK1 expression may affect plasma levels of glucose, triglycerides and free fatty acid during the duck domestication process. This work demonstrates for the first time in duck that PCK1 is a key gene in maintaining plasma glucose homeostasis during fasting and that the upregulated expression of PCK1 may be responsible for constant plasma free fatty acid level by the glyceroneogenesis process.

Diagnostic value of recombinant Tp0821 protein in serodiagnosis for syphilis

Syphilis is a multistage sexually transmitted disease that remains a serious public health concern worldwide. The coexistence of Treponema pallidum with other closely related members of spirochaeta, such as Leptospira spp. and Borrelia burgdorferi, has complicated the serodiagnosis due to cross-reactive antigens. In this study, recombinant Tp0821 protein was expressed in Escherichia coli and purified by metal affinity chromatography. Then enzyme-linked immunosorbent assays (ELISAs) based on Tp0821 for the detection of specific antibodies were established. The relative positive rates of the IgM ELISA and the IgG ELISA were found to be 91·0 and 98·3%, respectively, when screening 578 syphilis specimens. The specificities were 94·3 and 100%, respectively, when cross-checking with serum samples obtained from 30 patients with Lyme disease, five patients with leptospirosis, and 52 uninfected controls. In addition, relative positive rates and specificities of Tp0821 for human sera were all 100% in Western blotting. When compared to the syphilis diagnostic tests commonly used in clinical settings, we found that the results of Tp0821-based ELISAs correlated well with the results of the treponemal tests, specifically the T. pallidum particle agglutination (TP-PA) test and the chemiluminescent immunoassay (CIA). Thus, these findings identify Tp0821 as a novel serodiagnostic candidate for syphilis.

SIGNIFICANCE AND IMPACT OF THE STUDY

In this study, we expressed and purified the Treponema pallidum protein Tp0821 and developed Tp0821-based enzyme-linked immunosorbent assays (ELISAs) for the detection of specific antibodies. The serodiagnostic performance of the recombinant protein was then evaluated. When compared to the results of syphilis diagnostic tests commonly used in clinical settings, we found that the reactivities of syphilitic sera with the recombinant antigen correlated well with the results of the treponemal tests, specifically the T. pallidum particle agglutination (TP-PA) test and the chemiluminescent immunoassay (CIA). Thus, the recombinant protein shows promise as a new diagnostic antigen in the ELISAs.

Systematic tracking of altered modules identifies disrupted pathways in teratozoospermia

The objective of this study was to identify disrupted pathways in teratozoospermia by systematically tracking dysregulated modules in reweighted protein-protein interaction (PPI) networks. We inferred and reweighted the PPI networks of normal and teratozoospermia groups based on Spearman correlation coefficients. Modules in the PPI networks were explored via a clique-merging algorithm and altered modules were identified based on maximum weight bipartite matching. Furthermore, pathway-enrichment analyses of genes in altered modules were performed by Database for Annotation, Visualization, and Integrated Discovery (DAVID) to illuminate the biological pathways in teratozoospermia. A total of 20,102 genes were screened from the expression profile. We explored 2406 and 2101 modules in normal and disease PPI networks, respectively. Moreover, we obtained 875 altered modules by comparing modules in normal and teratozoospermia PPI networks. At P < 0.01, the genes involved in 2855 interactions with score changes >1 were mainly enriched in 66 pathways and the genes in altered modules were enriched in 71 pathways. The activity genes (missed and added genes in the disrupted modules) were enriched in 41 common pathways. There were 36 mutual enriched pathways under the five different conditions. Moreover, the cell cycle pathway was disrupted in the first 10 pathways of each condition. This study provides a powerful biomarker discovery platform to better understand the progression of teratozoospermia by systematically tracking dysregulated modules. This method uncovered potential diagnostic and therapeutic targets of teratozoospermia. This information might lead to improved monitoring and treatment of teratozoospermia.

The dissemination mode of drug-resistant genes in Enterobacter cloacae

BACKGROUND

Enterobacter cloacae (E. cloacae) infection has the highest mortality rate among Enterobacter infections. This study aimed to determine the prevalence and the transmission route of the class I integron, qnr genes, and CTX-M ESBLs genes in clinical isolates and to analyse the association between the prevalence of MDR genes and the antibiotic resistance of E. cloacae.

MATERIALS AND METHODS

The antibiotic susceptibility was tested the agar dilution method. The class I integron, qnr genes, and CTX-M ESBLs genes were detected by polymerase chain reaction (PCR). The prevalence data were analysed with the Chi-square test.

RESULTS

In the 100 clinical isolates, the class I integron-positive rate was 65%, with 12% on chromosome, 15% on plasmids and 38% on both. The positive rate of qnr genes was 37% with plasmid location. The positive rates for qnrA, qnrB and qnrS were 6%, 23% and 8%, respectively. The CTX-M ESBLs-positive rate was 34%. For CTX-M-1 ESBLs, 15% were on chromosome, 6% on plasmids and 4% on both; for CTX-M-9 ESBLs, 1% was on chromosome and 7% on plasmid; for CTX-M-25 ESBLs, 3% were on chromosome and 1% on plasmid.

CONCLUSION

Antibiotic resistance genes may be horizontally and vertically disseminated among E. cloacae, which helps multidrug-resistant (MDR) strains of E. cloacae to be successful nosocomial agents.

Synergistic in vitro anti-tumor effect of letrozole and everolimus on human endometrial carcinoma Ishikawa cells

OBJECTIVES

To investigate the in vitro effect of the use of combination of letrozole and everolimus on the proliferation and apoptosis of human endometrial carcinoma Ishikawa cells.

MATERIALS AND METHODS

Different concentrations of letrozole alone or in combination with everolimus were added to Ishikawa cell cultures in vitro. Cell viability was assessed using MTT assay. Double staining with Annexin-V-FITC was used to detect the cell apoptosis by the flow cytometry (FCM). The expression of PTEN and 4E-BP1 proteins was analyzed with Western blotting.

RESULTS

Letrozole by itself inhibited cell viability and decreased the invasiveness of Ishikawa cells. The anti-tumor effect of letrozole in combination with everolimus was improved compared to letrozole alone.

CONCLUSIONS

Letrozole and everolimus synergistically inhibit the proliferation and induce cell apoptosis by inhibiting the cell signal pathway PI3K/Akt/mTOR and inducing cell apoptosis, thus showing a promising anti-tumor effectiveness.

Decelerated transport and its mechanism of 2,5-hexanedione on middle-molecular-weight neurofilament in rat dorsal root ganglia cells

Chronic exposure to n-hexane induces peripheral-central axonopathy, mediated by its metabolite 2,5-hexanedione (2,5-HD), in occupational workers and experimental animals, but the underlying mechanism is still unclear. In the current study, we investigated the effects of 2,5-HD on middle-molecular-weight neurofilament (NF-M) axonal transport using live-cell imaging technique in cultured rat dorsal root ganglia (DRG) cells. PA-GFP-NF-M plasmid was transfected into DRG neurons and live-cell imaging was performed to observe the slow axonal transport of NF-M. The levels of cytoskeleton and motor proteins in DRG cells were detected by Western-blot and the concentration of ATP was determined using an ATP Assay Kit. The results showed that 2,5-HD administration resulted in a decrease of NF-M axonal transport and a reduction of three neurofilament subunits levels in DRG cells. Furthermore, 2,5-HD exposure significantly decreased ATP contents and the protein levels of kinesin heavy chain (KHC). These findings indicated that 2,5-HD reduced slow axonal transport, neurofilaments cargoes, motor proteins and ATP energy in rat DRG cells, which may contribute to 2,5-HD-induced neurotoxicity.

Effects of polyunsaturated fatty acids on endometrial carcinoma Ishikawa cells

OBJECTIVE

This study aimed to explore the effects and mechanisms of polyunsaturated fatty acids in the endometrial carcinoma Ishikawa cells.

MATERIALS AND METHODS

The Ishikawa cells were treated with n-6 PUFAs, n-3 PUFAs, or the mixture of n-6/n-3 PUFAs at a ratio of 1:1/10:1. Cell proliferation was quantified by MTT assay, while expressions of Akt, mTOR and VEGF mRNAs by PCR.

RESULTS

Treatment with n-6 PUFAs and 10:1 n-6/n-3PUFAs markedly promoted cell proliferation and up-regulated expressions of Akt, mTOR and VEGF mRNAs. Further, n-3 PUFAs and 1:1 n-6/n-3 PUFAs markedly suppressed cell proliferation and down-regulated expressions of Akt, mTOR and VEGF mRNAs.

CONCLUSIONS

Different ratios of n-6/n-3PUFAs exhibit differential effects on the endometrial carcinoma Ishikawa cells through the PI3k/Akt/mTOR signaling pathway and differentially regulate VEGF expression.

Thermal Conductivity and Phonon Engineering in Low-Dimensional Structures

Understanding phonon heat conduction mechanisms in low-dimensional structures is of critical importance for low-dimensional thermoelectricity. In this paper, we discuss heat conduction mechanisms in two-dimensional (2D) and one-dimensional (1D) structures. Models based on both the phonon wave picture and particle picture are developed for heat conduction in 2D superlattices. The phonon wave model, based on the acoustic wave equations, includes the effects of phonon interference and tunneling, while the particle model, based on the Boltzmann transport equation, treats the internal as well interface scattering of phonons. For 1D systems, both the Boltzmann transport equation and molecular dynamics simulation approaches are employed. Comparing the modeling results with experimental data suggest that the interface scattering of phonons plays a crucial role in the thermal conductivity of low-dimensional structures. We also discuss the minimum thermal conductivity of low-dimensional structures based on a generalized thermal conductivity integral, and suggest that the minimum thermal conductivities of low-dimensional systems may differ from those of their corresponding bulk materials. The discussion leads to alternative ways to reduce thermal conductivity based on the propagating phonon modes.

Effects of morphine and its withdrawal on Y-maze spatial recognition memory in mice

Effects of morphine on acquisition and retrieval of memory have been proven in the avoidance paradigms. In present study, we used a two-trial recognition Y-maze to test the effects of acute morphine and morphine withdrawal on spatial recognition memory. The Y-maze is based on the innate tendency of rodents to explore novel environments and therefore avoid punishment and reward.

RESULTS

1) Pre-training morphine 10 mg/kg impaired the recognition spatial memory of acquisition after a 1 h inter-trial interval (ITI), whereas morphine 2.5, 5 and 10 mg/kg showed impairment after 2 h ITI. 2) Pre-retention morphine 5, 10 mg/kg disrupted the retrieval of memory after 1 h ITI. 3) Morphine 5 and 10 mg/kg caused hyper-locomotor activity depending on the state. 4) Mice withdrawn from morphine 40 mg/kg but not 10 mg/kg for 3 days showed amnesia in Y-maze. Our data suggested that acute morphine impaired the acquisition and retrieval of spatial recognition memory and increased the locomotor activity in the Y-maze depending on the dose and state. Moreover, withdrawal from chronic morphine also impaired acquisition in the Y-maze depending on the dose and state.

Electron affinities of heavier phosphoryl and thiophosphoryl halides APX3 (A = O, S and X = Br, I)

We carried out computational studies of OPX3 and SPX3 (X = Br and I) molecules and their corresponding anions using density functional theory, Møller-Plesset, and CCSD(T) methods with newly developed model core potentials (MCP). Reliabilities of the MCP were demonstrated by comparing experimental and calculated results. We computed the geometric structure, electron affinities, and electrostatic moments using systematic sequences of the dzp-, tzp-, and qzp-quality basis sets. Both C3v and Cs symmetries were assumed to ascertain that minima on the potential energy surface were found. Infrared and Raman frequencies were calculated and compared with available experimental data. Natural population analyses were performed and used to determine distribution of the extra electron in anions.

Informational masking in profile analysis: comparing ideal and human observers

Predictions from an ideal observer model are compared with human thresholds for two profile analysis tasks. Past work has shown that ideal observer models reasonably account for human thresholds when the profile components are fixed in frequency and amplitude. Randomly varying the frequencies of the tones making up the profile leads to higher thresholds. Owing in part to large interobserver variation, the ideal observer model is not successful in accounting for the pattern of psychophysical thresholds associated with increases in frequency uncertainty. The ideal observer also fails to account for the results of a recent profile analysis experiment in which amplitude randomization was studied [Lentz JJ, Richards VM: J. Acoust. Soc. Am. 102: 535-541, 1998]. Overall, the ideal observer predicts smaller effects of uncertainty on thresholds than are observed in psychophysical experiments.

High frequency of allelic loss in dysplastic lichenoid lesions

Oral lichen planus (OLP) is a common mucosal condition that is considered premalignant by some, whereas others argue that only lichenoid lesions with epithelial dysplasia are at risk of progressing into oral carcinoma. A recent study from this laboratory used microsatellite analysis to evaluate OLP for loss of heterozygosity (LOH) at loci on three chromosomal arms (3p, 9p, and 17p) (Am J Path 1997;Vol151:Page323-Page327). Loss on these arms is a common event in oral epithelial dysplasia and has been associated with risk of progression of oral leukoplakia to cancer. The data showed that, although dysplastic epithelium demonstrated a high frequency of LOH (40% for mild dysplasia), a significantly lower frequency of LOH was noted in OLP (6%), which is even lower than that in hyperplasia (14%). Such results do not support OLP as a lesion at risk for malignant transformation. As a second step of the research, we determined LOH frequencies in 61 dysplastic lichenoid lesions (mild 35; moderate 19; severe 7) using the same microsatellite markers and compared these results with data obtained from the first study and from 13 normal mucosal specimens. Dysplastic lichenoid lesions showed a high frequency of loss (54% for lichenoid lesions with mild dysplasia), but values did not differ significantly from those observed in dysplasia of similar degree without lichenoid appearance. None of the normal mucosa demonstrated LOH. Epithelial dysplasia is a sign of malignant risk, independent of lichenoid changes. Such results suggest that pathologists should search for dysplasia carefully in lesions that otherwise qualify as OLP and that caution should be used when discounting dysplasia as being merely a reactive condition in lichenoid lesions.

Stretch-activated whole cell currents in adult rat cardiac myocytes

Mechanoelectric transduction can initiate cardiac arrhythmias. To examine the origins of this effect at the cellular level, we made whole cell voltage-clamp recordings from acutely isolated rat ventricular myocytes under controlled strain. Longitudinal stretch elicited noninactivating inward cationic currents that increased the action potential duration. These stretch-activated currents could be blocked by 100 microM Gd(3+) but not by octanol. The current-voltage relationship was nearly linear, with a reversal potential of approximately -6 mV in normal Tyrode solution. Current density varied with sarcomere length (SL) according to I (pA/pF) = 8.3 - 5.0 SL (microm). Repeated attempts to record single channel currents from stretch-activated ion channels failed, in accord with the absence of such data from the literature. The inability to record single channel currents may be a result of channels being located on internal membranes such as the T tubules or, possibly, inactivation of the channels by the mechanics of patch formation.