Changes in the actinomycetal communities during continuous thermophilic composting as revealed by denaturing gradient gel electrophoresis and quantitative PCR

Actinomycetes degrade cellulose and solubilize lignin during composting. Changes in the diversity of the actinomycetal communities and the 16S rDNA copy numbers of actinomycetes were monitored by denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR), respectively, during continuous thermophilic composting (CTC) and traditional composting (TC). qPCR indicated that the copy numbers from the CTC samples were 25-80% higher than those from the TC samples during similar phases of active composting and they were lower than 3×10(9) gene copies/g (dry weight) in the mature compost from both runs. DGGE showed a more diverse actinomycetal community in the CTC than in TC, averaging 16 bands as compared to 12 bands, at the post peak temperature phase. The study suggested that temperatures higher than 50 °C in CTC benefited the growth of actinomycetes.

Effects of ethanol-wet bonding technique on root dentine adhesion

OBJECTIVE

To investigate the effects of ethanol-wet bonding on the adhesion of experimental hydrophobic and commercial hydrophilic adhesives to root dentine.

METHODS

A total of 43 single-rooted integrated human premolars were selected and sectioned. Of the 86 initially obtained specimens, 66 were randomly and equally divided into water-wet bonding and ethanol-wet bonding groups (n = 33). The specimens of each group were subdivided into three subgroups (n = 11) based on different adhesives: two experimental hydrophobic adhesives (Bis-GMA/TEGDMA, BT; and UDMA/TEGDMA, UT) and one commercial hydrophilic adhesive (Adper™ Single Bond 2, SB). The root surfaces were ground, acid-etched and rinsed and resin composite applied. After storing in distilled water for 24 h at 37°C, the shear bond strength (SBS) of each specimen was measured. A sample from each subgroup was randomly selected and prepared for scanning electron microscopy (SEM) analysis. The remaining 20 specimens were used in the contact angle (CA) experiment, and the values of CA were measured. SBS was analysed with two-way ANOVA/Tukey's multiple comparison test and CA with independent sample t test.

RESULTS

A significant increase in SBS to root dentine was observed in the ethanol-wet bonding group compared with the traditional water-wet bonding group. The experimental hydrophobic adhesives (UT group) with ethanol-wet bonding presented the highest SBS (22.44 ± 3.32 MPa). CA increased significantly after the dentine surfaces were dried, especially for the water-saturated group.

CONCLUSION

The adhesion to root dentine surfaces with ethanol-wet bonding may be superior to water-wet bonding.

Abstract P4-02-20: Plasticity of the ER and HER2 Signaling Networks Results in Compensatory Escape Pathways Contributing to Treatment Resistance

Bidirectional crosstalk between the estrogen receptor (ER) and HER2 has been demonstrated in preclinical model systems. We have previously shown in HER2+ breast cancer cells with low ER that potent HER2- targeted therapy results in ER reactivation that functions as an escape pathway to evade therapeutic inhibition. Here we investigated the role of HER pathway components in resistance to endocrine therapies using UACC812 cells, which are endogenously amplified for HER2. Endocrine resistant (R) derivatives of the UACC812 line were developed through long-term (>6 months) culturing with estrogen deprivation (ED) alone or with 4-OH-tamoxifen (Tam, 10-7M). Endocrine treatment [continued ED, estrogen (E2, 10-9M), Tam (10-7M), or fulvestrant (Ful, 10-7M)] of parental cells slowed cell growth compared to estrogen treatment (P<0.01). EDR and TamR derivatives treated with any of the endocrine therapies, however, exhibited the same growth rates as with estrogen, validating the completely resistant phenotype of our clones. By immunoblot analysis, the resistant derivatives, TamR and EDR, showed a striking and complete loss of ER expression and its downstream gene products including PR, IGF-1R, and IRS-1. In contrast, both resistant lines exhibited significant upregulation of HER pathway components including marked increases in total and phosphorylated (p) EGFR, further upregulation of pHER2, and marked increases in the downstream signaling moieties pMAPK, pAkt, pFAK, pSrc, and pFOXO3a. In contrast, levels of pHER3 were markedly reduced at resistance. Since our in vitro data suggested that ER and HER2 compensate for inhibition of each other's pathways, we next examined whether simultaneous inhibition of both pathways can circumvent the development of resistance in an in vivo xenograft model. Athymic nude mice bearing UACC812 xenografts, established in the presence of E2 supplementation, were randomized to continued E2, endocrine therapies alone (ED, Tam, or Ful), anti-HER2 alone [lapatinib (L), trastuzumab (T), or L+T], or the combination of endocrine and anti-HER2 therapies (ED with L, T, or L+T). We found that tumors were stimulated by E2, as well as by Tam (as a mechanism of de novo resistance), while still being inhibited, though only temporarily (2-3 months), by ED and Ful. Anti-HER2 therapy alone only slowed down (L or T) or stabilized (L+T) tumor growth. In contrast, in the presence of both ED and anti-HER2 therapies, most tumors completely regressed. However, only the potent L+T plus ED regimen achieved continuous long term (>200 days) complete regression in all mice. Our results further illustrate the plasticity of the ER and HER2 pathways and provide additional support for the role of the HER network, especially EGFR, in resistance to endocrine therapy in ER+/HER2+ breast cancer. The data emphasize the need for complete HER blockade for optimal therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-02-20.

Fabrication and biocompatibility of an antimicrobial composite membrane with an asymmetric porous structure

A composite slurry from silver ion-substituted nano-hydroxyapatite, titania nano-particles and polyamide 66 (Ag-nHA/TiO(2)/PA66) was prepared and used to fabricate a novel antimicrobial membrane with a gradient porous structure for guided bone regeneration (GBR). Subsequently, assays were performed to determine the cytocompatibility, as well as the bone biocompatibility of the prepared membranes. To investigate the cytocompatibility of the Ag-nHA/TiO(2)/PA66 membrane, in vitro studies were done with osteoblast-like cells (MG63) and the viability, alkaline phosphatase activity (ALP) and morphology of cells cultured on the membrane were determined. The bone biocompatibility of the membranes was finally assessed in animal experiments, in which nano-hydroxyapatite/polyamide 66 (nHA/PA66) and pure polyamide 66 (PA66) membranes were compared. The in vitro cell-culture experiments showed that Ag-nHA/TiO(2)/PA66 antimicrobial membrane evoked good cell affinity and cytocompatibility. The in vivo study showed that Ag-nHA/TiO(2)/PA66 asymmetric porous barrier membrane resulted in complete closure of 5-mm bone defects as created in the skull of rats after 8 weeks of implantation. In conclusion, the Ag-nHA/TiO(2)/PA66 membrane has the potential to be applied in GBR, especially in infected tissue or areas with high bacteria concentration.

p85α mediates p53 K370 acetylation by p300 and regulates its promoter-specific transactivity in the cellular UVB response

Inducible acetylation of p53 at lysine residues has a great impact on regulating the transactivation of this protein, which is associated with cell growth arrest and/or apoptosis under various stress conditions. However, the factor(s) for regulating p53 acetylation remains largely unknown. In the current study, we have shown that p85α, the regulatory subunit of phosphatidylinositol-3-kinase, has a critical role in mediating p53 acetylation and promoter-specific transactivation in the ultraviolet B (UVB) response. Depletion of p85α in mouse embryonic fibroblasts significantly impairs UVB-induced apoptosis, as well as p53 transactivation and acetylation at Lys370 (Lys373 of human p53); however, the accumulation, nuclear translocation and phosphorylation of p53 are not affected. Interestingly, p85α binds to p300, promotes the p300-p53 interaction and the subsequent recruitment of the p53/p300 complex to the promoter region of the specific p53 target gene in response to UVB irradiation. Moreover, ablation of p53 acetylation at Lys370 by site-directed mutagenesis dramatically suppresses UVB-induced expression of the specific p53-responsive gene as well as cell apoptosis. Therefore, we conclude that p85α is a novel regulator of p53-mediated response under certain stress conditions, and targeting the p85α-dependent p53 pathway may be promising for cancer therapy.

WW domain-mediated interaction with Wbp2 is important for the oncogenic property of TAZ

The transcriptional co-activators YAP and TAZ are downstream targets inhibited by the Hippo tumor suppressor pathway. YAP and TAZ both possess WW domains, which are important protein–protein interaction modules that mediate interaction with proline-rich motifs, most commonly PPXY. The WW domains of YAP have complex regulatory roles as exemplified by recent reports showing that they can positively or negatively influence YAP activity in a cell and context-specific manner. In this study, we show that the WW domain of TAZ is important for it to transform both MCF10A and NIH3T3 cells and to activate transcription of ITGB2 but not CTGF, as introducing point mutations into the WW domain of TAZ (WWm) abolished its transforming and transcription-promoting ability. Using a proteomic approach, we discovered potential regulatory proteins that interact with TAZ WW domain and identified Wbp2. The interaction of Wbp2 with TAZ is dependent on the WW domain of TAZ and the PPXY-containing C-terminal region of Wbp2. Knockdown of endogenous Wbp2 suppresses, whereas overexpression of Wbp2 enhances, TAZ-driven transformation. Forced interaction of WWm with Wbp2 by direct C-terminal fusion of full-length Wbp2 or its TAZ-interacting C-terminal domain restored the transforming and transcription-promoting ability of TAZ. These results suggest that the WW domain-mediated interaction with Wbp2 promotes the transforming ability of TAZ.

Association between the ACTN3 R577X polymorphism and female endurance athletes in China

The α-actinin 3 ( ACTN3) gene is absent in 18% of healthy white individuals owing to homozygosity for a premature stop codon polymorphism (rs1815739) and is only expressed in the Z line of fast glycolytic muscle fibres. Previous studies have shown highly significant association between ACTN3 genotype and sprint/power performance, while the nonfunctional allele (577X) was believed to provide an advantage for endurance performance. In this study we tested whether XX genotype was over-represented in Chinese endurance athletes compared to the general population. In a study of 250 Chinese endurance athletes of provincial or national competitive standard and 450 controls, we proved that the ACTN3 XX genotype (21.2 vs. 15.8%; P=0.02) and X allele (51.3 vs. 41.1%; P=0.019) were significantly over-represented in female endurance athletes compared to controls, while no genotype-related differences were observed in male endurance athletes. Besides, the frequency of the ACTN3 XX genotype (28.6%) was the highest in a group of highly elite athletes compared with other groups, which supported the hypothesis that the absence of α-actinin-3 provided some sort of advantage for endurance athletes. Our results indicated that ACTN3 R577X polymorphism was associated with endurance performance in female athletes but not male athletes in China.

Van der waals surfaces in molecular modeling: implementation with real-time computer graphics

A method is described for generating van der Waals molecular surfaces with a real-time interactive calligraphic color display system. These surfaces maintain their proper representation during bond rotation and global transformations, and an interior atom removal method yields a comprehensible picture of the molecular surface for large molecules. Both algorithms are faster than previous methods. This combination provides a powerful tool for real-time interactive molecular modeling.

Optimization of handling and refrigerated storage of guppy Poecilia reticulata sperm

Sperm collection methods and the effect of osmolality, ions, sugar, temperature, pH and dilution ratio on sperm motility were investigated in guppies Poecilia reticulata. The present study revealed that the sperm was motile in a wide range of osmolalities (200-470 mOsm kg(-1)) either in Hanks balanced-salt solution (HBSS) or in non-electrolyte solutions such as glucose or sucrose. Sperm collected from crushing testes yielded lower motility and shorter motility duration than samples collected without crushing but gentle disruption. Dilution ratios within the range of 1:50 to 1:500 of sperm to HBSS had minimal effect on sperm motility during extended refrigerated storage. Examination of storage temperature showed that refrigerated storage at 4 degrees C was superior to room temperature (25 degrees C). Sperm was found to tolerate a wide range of pH from 5.6 to 7.8, but motility was affected negatively by pH values >7.8.

Genome-wide haplotype association analysis and gene prioritization identify CCL3 as a risk locus for rheumatoid arthritis

Rheumatoid arthritis (RA) is a common autoimmune disease caused by a complex interaction of multiple genetic variants and environmental factors. The association between RA and genetic susceptibility loci has been observed in many different populations, and most studies have focused on univariate analyses of single nucleotide polymorphisms. We performed a genome-wide haplotype association study and prioritized RA-related genes within 100 kb in either direction of significant haplotypes (P < 0.0001), based on their similarity to known RA susceptibility genes. The results showed that the chemokine CCL3 was associated with susceptibility to RA. A haplotype that located CCL3 on chromosome 17q12 had significant correlation with RA (P = 7.56E-05), and the global similarity score of CCL3 was ranked in the top of all RA-related genes, excluding known susceptibility genes (P = 8.42E-07). Our findings provide further evidence for the potential importance of the chemokine CCL3 in RA, and will facilitate the further understanding of its role in immunological regulation and the pathogenesis of RA.

Preservation of beam emittance in the presence of ion motion in future high-energy plasma-wakefield-based colliders

The preservation of beam quality in a plasma wakefield accelerator driven by ultrahigh intensity and ultralow emittance beams, characteristic of future particle colliders, is a challenge. The electric field of these beams leads to plasma ions motion, resulting in a nonlinear focusing force and emittance growth of the beam. We propose to use an adiabatic matching section consisting of a short plasma section with a decreasing ion mass to allow for the beam to remain matched to the focusing force. We use analytical models and numerical simulations to show that the emittance growth can be significantly reduced.

Note: Determination of effective gas diffusion coefficients of stainless steel films with differently shaped holes using a Loschmidt diffusion cell

In this work, an in-house made Loschmidt diffusion cell is used to measure the effective O(2)-N(2) diffusion coefficients through four porous samples of different simple pore structures. One-dimensional through-plane mass diffusion theory is applied to process the experimental data. It is found that both bulk diffusion coefficient and the effective gas diffusion coefficients of the samples can then be precisely determined, and the measured bulk one is in good agreement with the literature value. Numerical computation of three-dimensional mass diffusion through the samples is performed to calculate the effective gas diffusion coefficients. The comparison between the measured and calculated coefficient values shows that if the gas diffusion through a sample is dominated by one-dimensional diffusion, which is determined by the pore structure of the sample, these two values are consistent, and the sample can be used as a standard sample to test a gas diffusion measurement system.