Important role of N108 residue in binding of bovine foamy virus transactivator Tas to viral promoters

BACKGROUND

Bovine foamy virus (BFV) encodes the transactivator BTas, which enhances viral gene transcription by binding to the long terminal repeat promoter and the internal promoter. In this study, we investigated the different replication capacities of two similar BFV full-length DNA clones, pBS-BFV-Y and pBS-BFV-B.

RESULTS

Here, functional analysis of several chimeric clones revealed a major role for the C-terminal region of the viral genome in causing this difference. Furthermore, BTas-B, which is located in this C-terminal region, exhibited a 20-fold higher transactivation activity than BTas-Y. Sequence alignment showed that these two sequences differ only at amino acid 108, with BTas-B containing N108 and BTas-Y containing D108 at this position. Results of mutagenesis studies demonstrated that residue N108 is important for BTas binding to viral promoters. In addition, the N108D mutation in pBS-BFV-B reduced the viral replication capacity by about 1.5-fold.

CONCLUSIONS

Our results suggest that residue N108 is important for BTas binding to BFV promoters and has a major role in BFV replication. These findings not only advances our understanding of the transactivation mechanism of BTas, but they also highlight the importance of certain sequence polymorphisms in modulating the replication capacity of isolated BFV clones.

High-extinction virtually imaged phased array-based Brillouin spectroscopy of turbid biological media

Brillouin microscopy has recently emerged as a powerful technique to characterize the mechanical properties of biological tissue, cell, and biomaterials. However, the potential of Brillouin microscopy is currently limited to transparent samples, because Brillouin spectrometers do not have sufficient spectral extinction to reject the predominant non-Brillouin scattered light of turbid media. To overcome this issue, we combined a multi-pass Fabry-Perot interferometer with a two-stage virtually imaged phased array spectrometer. The Fabry-Perot etalon acts as an ultra-narrow band-pass filter for Brillouin light with high spectral extinction and low loss. We report background-free Brillouin spectra from Intralipid solutions and up to 100 μm deep within chicken muscle tissue.

Association of Dopamine Beta-Hydroxylase (DBH) Polymorphisms with Susceptibility to Parkinson's Disease

Background

The purpose of this study was to explore the association between 2 single-nucleotide polymorphisms (SNPs) in the dopamine β-hydroxylase (DBH) gene (rs1611115 and rs732833) and the susceptibility to Parkinson’s disease (PD).

Material/Methods

Polymerase chain reaction direct sequencing (PCR-DS) was used to test the genotypes of DBH polymorphisms in 95 PD patients and 100 healthy examinees frequency-matched with the former by age and sex. The genotype and allele distribution differences between the case and control groups were analyzed by chi-square test, and the relative risk of PD in southern Chinese populations was expressed by odds ratio (OR) and 95% confidence interval (CI). Hardy-Weinberg equilibrium (HWE) was also checked by chi-square test.

Results

The genotype and allele distribution frequencies in rs1611115 were obviously different between PD patients and the healthy control group (P<0.05). The TT genotype may lead to a 2.95 times higher risk of PD occurrence compared with the common genotype CC (OR=2.95, 95%CI=1.02–8.51), and the C allele increased risk of onset of PD (OR=1.81, 95%CI=1.17–2.82). Cognition of the PD patients was different between CC and CT+TT genotypes of rs1611115 (P=0.047).

Conclusions

DBH rs1611115 polymorphism was likely to be associated with the susceptibility to PD, but we did not find that rs732833 is a susceptibility marker for PD.

Multimodality Raman and photoacoustic imaging of surface-enhanced-Raman-scattering-targeted tumor cells

A multimodality Raman and photoacoustic imaging system is presented. This system has ultralow background and can detect tumor cells labeled with modified surface-enhanced-Raman-scattering (SERS) nanoparticles in vivo. Photoacoustic imaging provides microvascular context and can potentially be used to guide magnetic trapping of circulating tumor cells for SERS detection in animal models.

Investigation on the neutral and anionic BxAlyH2 (x + y = 7, 8, 9) clusters using density functional theory combined with photoelectron spectroscopy

The photoelectron experimental spectra measured at 266 nm and simulated spectra of B₂Al₅H₂⁻ and B₂Al₆H₂⁻ clusters.

Microhydration effects on the structures and electrophilic properties of cytidine

Adiabatic electron affinities (AEAs) for cytidine hydrates with up to four water molecules.

Monitoring photodynamic therapy with photoacoustic microscopy

Abstract. We present our work on examining the feasibility of monitoring photodynamic therapy (PDT)-induced vasculature change with acoustic-resolution photoacoustic microscopy (PAM). Verteporfin, an FDA-approved photosensitizer for clinical PDT, was utilized. With a 60-μm-resolution PAM system, we demonstrated the capability of PAM to monitor PDT-induced vasculature variations in a chick chorioallantoic membrane model with topical application and in a rat ear with intravenous injection of the photosensitizer. We also showed oxygen saturation change in target blood vessels due to PDT. Success of the present approach may potentially lead to the application of PAM imaging in evaluating PDT efficacy, guiding treatment, and predicting responders from nonresponders.

Microwave-assisted extraction and purification of chlorogenic acid from by-products of Eucommia Ulmoides Oliver and its potential anti-tumor activity

An efficient method for the rapid extraction, separation and purification of chlorogenic acid (CGA) from by-products of Eucommia Ulmoides Oliver (E. ulmoides) by microwave-assisted extraction (MAE) coupled with high-speed counter-current chromatography (HSCCC) was developed. The optimal MAE parameters were evaluated by response surface methodology (RSM), and they were extraction time of 12 min, microwave power of 420 W, ethanol concentration of 75 %, solvent/sample ratio of 30:1 (mL/g), yield of CGA reached 3.59 %. The crude extract was separated and purified directly by HSCCC using ethyl acetate-butyl alcohol-water (3:1:4, v/v) as the two-phase solvent system. The 14.5 mg of CGA with the purity of 98.7 % was obtained in one-step separation from 400 mg of crude extract. The chemical structure of CGA was verified with IR, ESI-MS analysis. Meanwhile, the purified CGA extract was evaluated by MTT assay and results indicate that CGA extract exhibited potential anti-tumor activity for AGS gastric cancer cell.

Association between PON1 L55M polymorphism and ischemic stroke: a systematic review and meta-analysis

OBJECTIVE

The present study aims to evaluate the relation between PON1 L55M polymorphism and ischemic stroke by a meta-analysis method.

METHODS

English and Chinese databases were retrieved to find qualified studies; a random or fixed effects model was used to merge the odds ratio (OR); Q test was used to assess the heterogeneity among studies, and Egger's test and funnel plot were used for the assessment of publication bias.

RESULTS

14 studies were included in the meta-analysis; in total populations, there was no association between PON1 gene L55M polymorphism and ischemic stroke in additive, dominant, and recessive model, respectively. Furthermore, we did not found associations between L55M and ischemic stroke in Asian or Caucasian population.

CONCLUSION

Available evidences suggested that L55M polymorphism had no effect on the risk of ischemic stroke. However, this conclusion needs further validation by larger sample and well-designed studies.

Risk factors for incidental durotomy during lumbar surgery: a retrospective study by multivariate analysis

OBJECTIVE

The purpose of the present study was to use a prospectively collected data to evaluate the rate of incidental durotomy (ID) during lumbar surgery and determine the associated risk factors by using univariate and multivariate analysis.

METHODS

We retrospectively reviewed 2184 patients who underwent lumbar surgery from January 1, 2009 to December 31, 2011 at a single hospital. Patients with ID (n=97) were compared with the patients without ID (n=2019). The influences of several potential risk factors that might affect the occurrence of ID were assessed using univariate and multivariate analyses.

RESULTS

The overall incidence of ID was 4.62%. Univariate analysis demonstrated that older age, diabetes, lumbar central stenosis, posterior approach, revision surgery, prior lumber surgery and minimal invasive surgery are risk factors for ID during lumbar surgery. However, multivariate analysis identified older age, prior lumber surgery, revision surgery, and minimally invasive surgery as independent risk factors.

CONCLUSION

Older age, prior lumber surgery, revision surgery, and minimal invasive surgery were independent risk factors for ID during lumbar surgery. These findings may guide clinicians making future surgical decisions regarding ID and aid in the patient counseling process to alleviate risks and complications.

Structures and bonding of auropolyboroenes [Au2(B4)xB3]−, [Au2(B4)xB2]2− and [Au2(B4)xB]+ (x = 2, 3): comparison with dihydride polyboroenes

Equilibrium structures of auropolyboroenes [Au₂(B₄)_xB₃]⁻, [Au₂(B₄)_xB₂]²⁻ and [Au₂(B₄)_xB]⁺ (x = 2, 3) are obtained from density functional theory-based calculations.

Zirconocene-catalyzed sequential ethylcarboxylation of alkenes using ethylmagnesium chloride and carbon dioxide

The zirconocene-catalyzed sequential ethylcarboxylation of alkenes using ethylmagnesium chloride and carbon dioxide has been developed. A range of alkenes were transformed into the corresponding carboxylic acids in high yields.

Consecutively reconstructing absorption and scattering distributions in turbid media with multiple-illumination photoacoustic tomography

We propose a theoretical framework for consecutively reconstructing absorption and scattering distributions in turbid soft tissue in an iterative manner. This approach takes advantage of the stability of a recently reported least-squares fixed-point iterative method for reconstructing an optical absorption coefficient map to iteratively update estimates of absorption and scattering for each iteration. Simulations demonstrate that this method converges to an accurate estimate of the optical properties within only a small number of iterations and is robust to noise at realistic signal-to-noise levels.

Regulation of adenosine triphosphate-sensitive potassium channels suppresses the toxic effects of amyloid-beta peptide (25-35)

In this study, we treated PC12 cells with 0-20 μM amyloid-β peptide (25-35) for 24 hours to induce cytotoxicity, and found that 5-20 μM amyloid-β peptide (25-35) decreased PC12 cell viability, but adenosine triphosphate-sensitive potassium channel activator diazoxide suppressed the decrease in PC12 cell viability induced by amyloid-β peptide (25-35). Diazoxide protected PC12 cells against amyloid-β peptide (25-35)-induced increases in mitochondrial membrane potential and intracellular reactive oxygen species levels. These protective effects were reversed by the selective mitochondrial adenosine triphosphate-sensitive potassium channel blocker 5-hydroxydecanoate. An inducible nitric oxide synthase inhibitor, Nω-nitro-L-arginine, also protected PC12 cells from amyloid-β peptide (25-35)-induced increases in both mitochondrial membrane potential and intracellular reactive oxygen species levels. However, the H2O2-degrading enzyme catalase could not reverse the amyloid-β peptide (25-35)-induced increase in intracellular reactive oxygen species. A 24-hour exposure to amyloid-β peptide (25-35) did not result in apoptosis or necrosis, suggesting that the increases in both mitochondrial membrane potential and reactive oxygen species levels preceded cell death. The data suggest that amyloid-β peptide (25-35) cytotoxicity is associated with adenosine triphosphate-sensitive potassium channels and nitric oxide. Regulation of adenosine triphosphate-sensitive potassium channels suppresses PC12 cell cytotoxicity induced by amyloid-β peptide (25-35).

S-sequence patterned illumination iterative photoacoustic tomography

Quantitatively reconstructing optical absorption using photoacoustic imaging is nontrivial. Theoretical hurdles, such as nonuniqueness and numerical instability, can be mitigated by using multiple illuminations. However, even with multiple illuminations, using ANSI-safety-limited fluence for practical imaging may result in poor performance owing to limited signal-to-noise ratio (SNR). We demonstrate the use of S-sequence coded patterned illumination to boost SNR while preserving the enhanced stability of multiple-illumination iterative techniques.

Probing the structural and electronic properties of small aluminum dideuteride clusters

Adsorption of deuterium on the neutral and anionic Aln(λ) (n=1-9, 13; λ=0, -1) clusters has been investigated systematically using density functional theory. The comparisons between the Franck-Condon factor simulated spectra and the measured photoelectron spectroscopy (PES) of Cui and co-workers help to search for the ground-state structures. The results showed that D2 molecule tends to be dissociated on aluminum clusters and forms the radial AlD bond with one aluminum atom. By studying the evolution of the binding energies, second difference energies and HOMO-LUMO gaps as a function of cluster size, we found Al2D2, Al6D2 and Al7D2(̄) clusters have the stronger relative stability and enhanced chemical stability. Also, considering the larger adsorption energies of these three clusters, we surmised that Al2, Al6 and Al7(̄) may be the better candidates for dissociative adsorption of D2 molecule among the clusters we studied. Furthermore, the natural population analysis (NPA) and difference electron density were performed and discussed to probe into the localization of the charges and reliable charge-transfer information in AlnD2 and AlnD2(̄) clusters.

Serotonin regulates osteoblast proliferation and function in vitro

The monoamine serotonin (5-hydroxytryptamine, 5-HT), a well-known neurotransmitter, also has important functions outside the central nervous system. The objective of this study was to investigate the role of 5-HT in the proliferation, differentiation, and function of osteoblasts in vitro. We treated rat primary calvarial osteoblasts with various concentrations of 5-HT (1 nM to 10 µM) and assessed the rate of osteoblast proliferation, expression levels of osteoblast-specific proteins and genes, and the ability to form mineralized nodules. Next, we detected which 5-HT receptor subtypes were expressed in rat osteoblasts at different stages of osteoblast differentiation. We found that 5-HT could inhibit osteoblast proliferation, differentiation, and mineralization at low concentrations, but this inhibitory effect was mitigated at relatively high concentrations. Six of the 5-HT receptor subtypes (5-HT_1A, 5-HT_1B, 5-HT_1D, 5-HT_2A, 5-HT_2B, and 5-HT_2C) were found to exist in rat osteoblasts. Of these, 5-HT_2A and 5-HT_1B receptors had the highest expression levels, at both early and late stages of differentiation. Our results indicated that 5-HT can regulate osteoblast proliferation and function in vitro.

The potential role of free chitosan in bone trauma and bone cancer management

Bone defects caused by fractures or cancer-mediated destruction are debilitating. Chitosan is commonly used in scaffold matrices for bone healing, but rarely as a free drug. We demonstrate that free chitosan promotes osteoblast proliferation and osteogenesis in mesenchymal stem cells, increases osteopontin and collagen I expression, and reduces osteoclastogenesis. Chitosan inhibits invasion of endothelial cells, downregulating uPA/R, MT1-MMP, cdc42 and Rac1. Better healing of bone fractures with greater trabecular bone formation was observed in mice treated with chitosan. Chitosan induces apoptosis in osteotropic prostate and breast cancer cells via caspase-2 and -3 activation, and reduces their establishment in bone. Chitosan is pro-apoptotic in osteosarcoma cells, but not their normal counterpart, osteoblasts, or chondrosarcoma cells. Systemic delivery of chitosan does not perturb angiogenesis, bone volume or instinctive behaviour in pregnant mice, but decreases foetal length and changes pancreatic secretory acini. With certain controls in place, chitosan could be useful for bone trauma management.