Panax ginseng has anti-infective activity against opportunistic pathogen Pseudomonas aeruginosa by inhibiting quorum sensing, a bacterial communication process critical for establishing infection

Virulent factors produced by pathogens play an important role in the infectious process, which is regulated by a cell-to-cell communication mechanism called quorum sensing (QS). Pseudomonas aeruginosa is an important opportunistic human pathogen, which causes infections in patients with compromised immune systems and cystic fibrosis. The QS systems of P. aeruginosa use N-acylated homoserine lactone (AHL) as signal molecules. Previously we have demonstrated that Panax ginseng treatment allowed the animals with P. aeruginosa pneumonia to effectively clear the bacterial infection. We postulated that the ability to impact the outcome of infections is partly due to ginseng having direct effect on the production of P. aeruginosa virulence factors. The study explores the effect of ginseng on alginate, protease and AHL production. The effect of ginseng extracts on growth and expression of QS-controlled virulence factors on the prototypic P. aeruginosa PAO1 and its isogenic mucoid variant (PAOmucA22) was determined. Ginseng did not inhibit the growth of the bacteria, enhanced the extracellular protein production and stimulated the production of alginate. However, ginseng suppressed the production of LasA and LasB and down-regulated the synthesis of the AHL molecules. Ginseng has a negative effect on the QS system of P. aeruginosa, may explain the ginseng-dependent bacterial clearance from the animal lungs in vivo in our previous animal study. It is possible that enhancing and repressing activities of ginseng are mutually exclusive as it is a complex mixture, as shown with the HPLC analysis of the hot water extract. Though ginseng is a promising natural synergetic remedy, it is important to isolate and evaluate the ginseng compounds associated with the anti-QS activity.

MicroRNA-101-mediated Akt activation and estrogen-independent growth

MicroRNAs are gene regulators that work through a posttranscriptional repression mechanism. Dysregulation of microRNA expression could lead to a variety of disorders, in particular, human cancer, and has also been implicated in antihormone therapy resistance. However, little is known whether microRNAs have a role in estrogen-independent growth, leading to tamoxifen resistance in estrogen receptor (ER)-positive tumors. In this study, we use an in vivo selection system against a microRNA library using the MCF-7 model and demonstrate that miR-101 promotes estrogen-independent growth and causes the upregulation of phosphorylated Akt (pAkt) without impacting the ER level or activity. Importantly, although miR-101 suppresses cell growth in normal estradiol (E2)-containing medium, it promotes cell growth in E2-free medium. Moreover, estrogen deprivation greatly enhances miR-101-mediated Akt activation. Finally, we show that MAGI-2 (membrane-associated guanylate kinase), a scaffold protein required for PTEN (phosphatase and tensin homolog) activity, is a direct target for miR-101; suppression of MAGI-2 by miR-101 reduces PTEN activity, leading to Akt activation. Taken together, these results not only establish a role for miR-101 in estrogen-independent signaling but also provide a mechanistic link between miR-101 and Akt activation.

Investigation of effects of the <i>MKK3</i> and <i>MKK6</i> genes on meat production traits in the pig (Brief Report)

Abstract. Skeletal muscle development is a complexity process involved in spatial and temporal expressions of numerous muscle differentiation-specific genes, which are controlled by a series of basic helix-loop-helix myogenic regulatory factors (MRFs) (HOUBA and TE PAS 2004). The recent studies have demonstrated that the p38 mitogen-activated protein kinase (MAPK) pathway is probably one of the major intracellular signaling pathways affecting myogenesis (KEREN et al. 2006, LIUÍS et al. 2006). The p38 MAPKs regulate the transcriptional activities of MRFs and function in the remodeling of chromatin at specific muscle-regulatory regions (LI et al. 2000, ZARUBIN et al. 2005). The genes involved in the p38 MAPK pathway have been poorly studied in pigs. The primary work on SNP discovery and association analyses of two important MAPK kinases encoding genes MKK3 (MAP2K3) and MKK6 (MAP2K6) was presented in the study, so as to identify the potential genetic markers useful for marker assisted selection (MAS) improving lean meat production.

High-cooperativity coupling of electron-spin ensembles to superconducting cavities

Electron spins in solids are promising candidates for quantum memories for superconducting qubits because they can have long coherence times, large collective couplings, and many qubits could be encoded into spin waves of a single ensemble. We demonstrate the coupling of electron-spin ensembles to a superconducting transmission-line cavity at strengths greatly exceeding the cavity decay rates and comparable to the spin linewidths. We also perform broadband spectroscopy of ruby (Al₂O₃:Cr(3+)) at millikelvin temperatures and low powers, using an on-chip feedline. In addition, we observe hyperfine structure in diamond P1 centers.

Combined effects of 17 common genetic variants on type 2 diabetes risk in a Han Chinese population

AIMS/HYPOTHESIS

The recent advent of genome-wide association studies has considerably accelerated the identification of type 2 diabetes loci. We aimed to investigate the combined effects of multiple genetic variants, alone or in combination with conventional risk factors, on type 2 diabetes and diabetes-related traits in Han Chinese.

METHODS

We genotyped 17 variants in 17 loci in a population-based Han Chinese cohort including 3,210 unrelated individuals. A genetic risk score (GRS) was calculated on the basis of these variants. The discriminatory ability was assessed by the area under the receiver operating characteristics curve.

RESULTS

The odds ratio for type 2 diabetes and hyperglycaemia with each GRS point (per risk allele) was 1.18 (95% CI 1.12-1.23, p = 1.3 x 10(-12)) and 1.12 (95% CI 1.09-1.16, p = 7.5 x 10(-14)), respectively. Compared with participants with GRS < or =11.0 (7.63%), those with GRS > or =19.0 (8.87%) had a 4.58-fold higher risk (95% CI 2.49-8.42) of type 2 diabetes. The GRS also showed a significant association with lower beta cell function estimated by HOMA of beta cell function (p = 8.4 x 10(-10)). In addition, we observed significant interactive effects between GRS and BMI on fasting glucose and HbA(1c) levels (p = 0.04 and p = 0.03 for interaction, respectively). Discrimination of diabetes risk was improved (p < 0.001) when the GRS was added to a model including clinical risk factors. The AUCs were 0.62 and 0.77, respectively, for the GRS and conventional clinic risk factors alone, and 0.79 when the GRS was added.

CONCLUSIONS/INTERPRETATION

In this Han Chinese population, the GRS of 17 combined variants modestly but significantly improved discrimination of the conventional risk factors for type 2 diabetes.

No association of interleukin-1 receptor antagonist VNTR polymorphism and rheumatoid arthritis susceptibility: a meta analysis

OBJECTIVES

Interleukin-1 receptor antagonist (IL-1Ra) is a natural anti-inflammatory molecule that blocks the action of IL-1 signaling. A variable-number tandem repeat polymorphism (VNTR) in IL-1Ra gene (IL-1RN) intron 2 has been reported to be associated with rheumatoid arthritis (RA), with inconsistent results. Here, we perform a meta-analysis to assess the common effect size of this polymorphism on RA susceptibility.

METHODS

Case-control studies on IL-1RN VNTR association with RA were searched up to January 2010. The effect summary odds ratio (OR) and 95% confidence intervals was obtained by meta- analysis.

RESULTS

A total of 15 studies involving in IL-1RN VNTR with RA susceptibility were included in this meta-analysis. No association between A2/A2 genotype and risk of RA to other genotypes (odds ratio [OR], 0.96; 95% CI =0.75-1.24, p=0.77), and between A2 allele and risk of RA (OR, 0.98; 95% CI=0.83-1.16, p=0.85), were demonstrated in the total meta-analysis. In both Asian and European subgroups, the overall effect of A2/A2 genotype and A2 allele also showed no significant difference.

CONCLUSIONS

This meta-analysis demonstrates that the IL-1RN VNTR polymorphism is not related to susceptibility to RA.

Use of chromosome walking in discovery of single-nucleotide polymorphism in noncoding regions of a candidate actin gene in Pinus radiata

Untranslated regions (UTRs) of eukaryotic mRNAs play crucial roles in post-transcriptional regulation of gene expression via the modulation of nucleocytoplasmic mRNA transport, translation efficiency, subcellular localization, and message stability. Single-nucleotide polymorphisms (SNPs) in UTRs of a candidate gene may also change the post-transcriptional regulation of a gene or function by nucleotide mutation. For species that have not been entirely sequenced genomically, new methods need to be devised to discover SNPs in noncoding regions of candidate genes. In this study, based on the expressed sequence tag (EST) of Pinus radiata (Monterey pine), we obtained all the sequences of UTRs of the actin gene by using a chromosome walking method. We also detected all the SNPs in and around the coding region of the actin gene. In this way, the full genomic sequence (2154 bp) of the actin gene was identified, including the 5&rsquo;UTR, introns, the coding sequence, and the 3&rsquo;UTR. PCR amplification and DNA fragment sequencing from 200 unrelated P. radiata trees revealed a total of 21 SNPs in the actin gene, of which 3 were located in the 5&rsquo;UTR, 3 in the introns, 10 in the coding sequence, and 5 in the 3&rsquo;UTR. We show that chromosome walking can be used for obtaining the sequence of UTRs, and then, based on this sequence, to discover SNPs in the noncoding regions of candidate genes from this species without an entire genomic sequence.

Role of neurocrine somatostatin on sphincter of Oddi contractility and intestinal ischemia reperfusion-induced acute pancreatitis in macaques

BACKGROUND

Intestinal ischemia-reperfusion (IIR) is implicated in the pathogenesis of severe acute pancreatitis (SAP). This study investigates the impact of neurocrine somatostatin (SST) on the contraction of sphincter of Oddi (SO) during IIR.

METHODS

Intestinal ischemia-reperfusion model in macaques was induced by occluding the superior mesenteric artery. Pancreatitis was confirmed by pancreatic histology and serum levels of amylase and lipase. SST and its receptors (SSTRs) in SO were visualized by immunohistochemistry. Effects of SST on the contraction of the isolated SO were recorded in vitro.

KEY RESULTS

Inflammatory scores of the pancreas and serum levels of amylase or lipase in the macaques that underwent IIR were significantly higher than those in the control group. The frequency and amplitude of phasic contraction of the circular muscle in SO was increased by SST in a concentration-dependent manner. Compared with the control group, SST innervation or SSTR2 expression in SO of macaques treated with IIR was increased 5.2 fold or 5.6 fold respectively. Prophylactic infusion of SST before IIR significantly reduced SST immunoreactive fibers in SO as compared to those in the IIR group and remarkably alleviated the pathophysiologic changes due to IIR.

CONCLUSIONS & INFERENCES

Increased SST innervation in SO during the early phase of IIR associated with the contraction of circular muscle of SO, which might be one of the promoting factors associated with the development of SAP. Prevention of IIR or intervention of SO contraction after occurrence of acute pancreatitis might be beneficial for preventing SAP.

The complex nature of serum C3 and C4 as biomarkers of lupus renal flare

To assess the relationship between serum C3 or C4 levels and lupus renal flare, C3 and C4 levels were measured bimonthly in 71 lupus nephritis patients for a mean of 35 months, during which time 70 renal flares were identified. Comparing baseline, pre-flare, and at-flare values indicated that neither C3 nor C4 levels decreased pre-flare, but both decreased on average significantly at flare. However, sensitivity/specificity for C3 (75%/71%) and C4 (48%/71%) were low. To account for other influencing factors, multiple regression was performed that included bimonthly values of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and genotype data on C3 (S/F), CRP (1846G > A), and the complement regulator factor H (Y402H). This analysis revealed that reduced levels of C4, but not C3, were independently associated with the two-month pre-flare period. Conversely, reduced levels of C3, but not C4, were independently associated with the flare visit. Significant pro-flare interactions included low C3 levels with the factor H 402HH-encoding genotype, and low CRP levels with the C3 F allele. Together these data suggest that C4 activation is critical for initiating renal flare while C3 activation is involved in the actual tissue damage, and that these effects are influenced by genetic variability in complement activation and regulation.

Involvement of p21 (waf1) in merlin deficient sporadic vestibular schwannomas

Previous studies have demonstrated that merlin acts as a tumor suppressor by blocking Ras-mediated signaling. However, the mechanism by which merlin controls cell proliferation has remained obscure. Here we show that merlin deficient tumors exhibited loss of p21, concomitant with elevated CDKs/cyclin D1 levels in sporadic vestibular schwannomas (VS) from clinic patients. Likewise, silencing of merlin gene expression in the cell lines resulted in down-regulation of p21. Furthermore, we find that merlin-enhanced p21 protein stability, rather than increased RNA accumulation, was responsible for the elevated p21 levels. Interestingly, p21 was required to maintain merlin levels and the inhibitory effect of merlin on Ras signaling was partially overridden by knockdown of p21. Consistent with the observation that over-expression of merlin arrested cell growth at G1-phase, the current study indicates that merlin exerts its antiproliferative effect, at least in part, by maintaining p21 expression, and loss of p21 is a prominent feature of merlin deficient schwannomas.