Publications search

Found 37769 matches. Displaying 4791-4800
LaCava J, Jiang H, Rout MP
Show All Authors

Protein Complex Affinity Capture from Cryomilled Mammalian Cells

JOVE-JOURNAL OF VISUALIZED EXPERIMENTS 2016 DEC; ?(118):? Article e54518
Affinity capture is an effective technique for isolating endogenous protein complexes for further study. When used in conjunction with an antibody, this technique is also frequently referred to as immunoprecipitation. Affinity capture can be applied in a bench-scale and in a high-throughput context. When coupled with protein mass spectrometry, affinity capture has proven to be a workhorse of interactome analysis. Although there are potentially many ways to execute the numerous steps involved, the following protocols implement our favored methods. Two features are distinctive: the use of cryomilled cell powder to produce cell extracts, and antibody-coupled paramagnetic beads as the affinity medium. In many cases, we have obtained superior results to those obtained with more conventional affinity capture practices. Cryomilling avoids numerous problems associated with other forms of cell breakage. It provides efficient breakage of the material, while avoiding denaturation issues associated with heating or foaming. It retains the native protein concentration up to the point of extraction, mitigating macromolecular dissociation. It reduces the time extracted proteins spend in solution, limiting deleterious enzymatic activities, and it may reduce the non-specific adsorption of proteins by the affinity medium. Micron-scale magnetic affinity media have become more commonplace over the last several years, increasingly replacing the traditional agarose-and Sepharose-based media. Primary benefits of magnetic media include typically lower nonspecific protein adsorption; no size exclusion limit because protein complex binding occurs on the bead surface rather than within pores; and ease of manipulation and handling using magnets.
Jin JJ, Lee M, Bai B, Sun YW, Qu J, Rahmadsyah, Alfiko Y, Lim CH, Suwanto A, Sugiharti M, Wong LS, Ye J, Chua NH, Yue GH
Show All Authors

Draft genome sequence of an elite Dura palm and whole-genome patterns of DNA variation in oil palm

DNA RESEARCH 2016 DEC; 23(6):527-533
Oil palm is the world's leading source of vegetable oil and fat. Dura, Pisifera and Tenera are three forms of oil palm. The genome sequence of Pisifera is available whereas the Dura form has not been sequenced yet. We sequenced the genome of one elite Dura palm, and re-sequenced 17 palm genomes. The assemble genome sequence of the elite Dura tree contained 10,971 scaffolds and was 1.701Gb in length, covering 94.49% of the oil palm genome. 36,105 genes were predicted. Re-sequencing of 17 additional palm trees identified 18.1 million SNPs. We found high genetic variation among palms from different geographical regions, but lower variation among Southeast Asian Dura and Pisifera palms. We mapped 10,000 SNPs on the linkage map of oil palm. In addition, high linkage disequilibrium (LD) was detected in the oil palms used in breeding populations of Southeast Asia, suggesting that LD mapping is likely to be practical in this important oil crop. Our data provide a valuable resource for accelerating genetic improvement and studying the mechanism underlying phenotypic variations of important oil palm traits.
Taylor's law (TL) asserts that the variance in a species' population density is a power-law function of its mean population density: log(variance)=a+bxlog(mean). TL is widely verified. We show here that empirical time series of density of the Hokkaido gray-sided vole, Myodes rufocanus, sampled 1962-1992 at 85 locations, satisfied temporal and spatial forms of TL. The slopes (b +/- standard error) of the temporal and spatial TL were estimated to be 1.613 +/- 0.141 and 1.430 +/- 0.132, respectively. A previously verified autoregressive Gompertz model of the dynamics of these populations generated time series of density which reproduced the form of temporal and spatial TLs, but with slopes that were significantly steeper than the slopes estimated from data. The density-dependent components of the Gompertz model were essential for the temporal TL. Adding to the Gompertz model assumptions that populations with higher mean density have reduced variance of density-independent perturbations and that density-independent perturbations are spatially correlated among populations yielded simulated time series that satisfactorily reproduced the slopes from data. The slopes (b +/- standard error) of the enhanced simulations were 1.619 +/- 0.199 for temporal TL and 1.575 +/- 0.204 for spatial TL.
Condit RC, Williamson AL, Sheets R, Seligman SJ, Monath TP, Excler JL, Gurwith M, Bok K, Robertson JS, Kim D, Hendry RM, Singh V, Mac LM, Chen RT
Show All Authors

Unique safety issues associated with virus-vectored vaccines: Potential for and theoretical consequences of recombination with wild type virus strains

VACCINE 2016 DEC 12; 34(51):6610-6616
In 2003 and 2013, the World Health Organization convened informal consultations on characterization and quality aspects of vaccines based on live virus vectors. In the resulting reports, one of several issues raised for future study was the potential for recombination of virus-vectored vaccines with wild type pathogenic virus strains. This paper presents an assessment of this issue formulated by the Brighton Collaboration. To provide an appropriate context for understanding the potential for recombination of virus-vectored vaccines, we review briefly the current status of virus-vectored vaccines, mechanisms of recombination between viruses, experience with recombination involving live attenuated vaccines in the field, and concerns raised previously in the literature regarding recombination of virus-vectored vaccines with wild type virus strains. We then present a discussion of the major variables that could influence recombination between a virus-vectored vaccine and circulating wild type virus and the consequences of such recombination, including intrinsic recombination properties of the parent virus used as a vector; sequence relatedness of vector and wild virus; virus host range, pathogenesis and transmission; replication competency of vector in target host; mechanism of vector attenuation; additional factors potentially affecting virulence; and circulation of multiple recombinant vectors in the same target population. Finally, we present some guiding principles for vector design and testing intended to anticipate and mitigate the potential for and consequences of recombination of virus-vectored vaccines with wild type pathogenic virus strains. (C) 2016 Published by Elsevier Ltd.
Xiong XZ, Panchenko T, Yang S, Zhao S, Yan PQ, Zhang WH, Xie W, Li YY, Zhao YM, Allis CD, Li HT
Show All Authors

Selective recognition of Histone crotonylation by double PHD fingers of MOZ and DPF2

NATURE CHEMICAL BIOLOGY 2016 DEC; 12(12):1111-1118
Recognition of histone covalent modifications by 'reader' modules constitutes a major mechanism for epigenetic regulation. A recent upsurge of newly discovered histone lysine acylations, such as crotonylation (Kcr), butyrylation (Kbu), and propionylation (Kpr), greatly expands the coding potential of histone lysine modifications. Here we demonstrate that the histone-acetylation-binding double PHD finger (DPF) domains of human MOZ (also known as KAT6A) and DPF2 (also known as BAF45d) accommodate a wide range of histone lysine acylations with the strongest preference for Kcr. Crystal structures of the DPF domain of MOZ in complex with H3K14cr, H3K14bu, and H3K14pr peptides reveal that these non-acetyl acylations are anchored in a hydrophobic 'dead-end' pocket with selectivity for crotonylation arising from intimate encapsulation and an amide-sensing hydrogen bonding network. Immunofluorescence and chromatin immunoprecipitation (ChIP)-quantitative PCR (qPCR) showed that MOZ and H3K14cr colocalize in a DPF-dependent manner. Our studies call attention to a new regulatory mechanism centered on histone crotonylation readout by DPF family members.
Sirovich L
Show All Authors

A new structural approach to genomic discovery of disease: example of adult-onset diabetes

BIOLOGICAL CYBERNETICS 2016 DEC; 110(6):383-391
This paper reports on an investigation of disease discovery from genomic data, by methods which depart substantially from customary practices found in the investigation of genome-wide association studies. Such data in general are composed of the genomic content from two contrasting phenotypes, e.g., disease versus control populations, and the analysis proceeds under the hypothesis that populational dissimilarities might reveal disease risk alleles. The proposed suite of new methods is in part based on information theory (Shannon in Bell Syst Tech J 27:379-423, 1948a; Bell Syst Tech J 27:623-656, 1948b; Jaynes in Phys Rev 106:620-630, 1957), and strong evidence will be given of the effectiveness of this new approach. The methodology extends naturally and successfully to predicting genomic disposition to disease arising from large collections of weakly contributing genomic loci. Evidence will be advanced that the example of adult-onset diabetes ("type 2 diabetes") is such a candidate disease, and in this case, probably for the first time, it can be demonstrated that disease prediction is possible. Another novel element of this study is the search and identification of potential beneficial genomic loci that may counter a disease. The generality of the methodology suggests that it might extend to other diseases.
Breton G, Zheng SW, Valieris R, da Silva IT, Satija R, Nussenzweig MC
Show All Authors

Human dendritic cells (DCs) are derived from distinct circulating precursors that are precommitted to become CD1c(+) or CD141(+) DCs

JOURNAL OF EXPERIMENTAL MEDICINE 2016 DEC; 213(13):2861-2870
In humans, conventional dendritic cells (cDCs) exist as two unique populations characterized by expression of CD1c and CD141. cDCs arise from increasingly restricted but well-defined bone marrow progenitors that include the common DC progenitor that differentiates into the pre-cDC, which is the direct precursor of cDCs. In this study, we show that pre-cDCs in humans are heterogeneous, consisting of two distinct populations of precursors that are precommitted to become either CD1c(+) or CD141(+) cDCs. The two groups of lineage-primed precursors can be distinguished based on differential expression of CD172a. Both subpopulations of pre-cDCs arise in the adult bone marrow and can be found in cord blood and adult peripheral blood. Gene expression analysis revealed that CD172a(+) and CD172a(-) pre-cDCs represent developmentally discrete populations that differentially express lineage-restricted transcription factors. A clinical trial of Flt3L injection revealed that this cytokine increases the number of both CD172a(-) and CD172a(+) pre-cDCs in human peripheral blood.
El Azbaoui S, Sabri A, Ouraini S, Hassani A, Asermouh A, Agadr A, Abilkassem R, Dini N, Kmari M, Akhaddar A, Laktati Z, Aieche S, El Hafidi N, Ben Brahim F, Bousfiha AA, Ailal F, Deswarte C, Schurr E, Amar L, Bustamante J, Boisson-Dupuis S, Casanova JL, Abel L, El Baghdadi J
Show All Authors

Utility of the QuantiFERON((R))-TB Gold In-Tube assay for the diagnosis of tuberculosis in Moroccan children

INTERNATIONAL JOURNAL OF TUBERCULOSIS AND LUNG DISEASE 2016 DEC; 20(12):1639-1646
SETTING: The utility of interferon-gamma release assays (IGRAs), such as the QuantiFERON-TB Gold In-Tube (QFT-GIT) test, in diagnosing active tuberculosis (TB) in children is unclear and depends on the epidemiological setting. OBJECTIVE: To evaluate the performance of QFT-GIT for TB diagnosis in children living in Morocco, an intermediate TB incidence country with high bacille Calmette-Guerin vaccination coverage. DESIGN: We prospectively recruited 109 Moroccan children hospitalised for clinically suspected TB, all of whom were tested using QFT-GIT. RESULTS: For 81 of the 109 children, the final diagnosis was TB. The remaining 28 children did not have TB. QFT-GIT had a sensitivity of 66% (95%CI 52-77) for the diagnosis of TB, and a specificity of 100% (95%CI 88-100). The tuberculin skin test (TST) had lower sensitivity, at 46% (95%CI 33-60), and its concordance with QFT-GIT was limited (69%). Combining QFT-GIT and TST results increased sensitivity to 83% (95%CI 69-92). CONCLUSION: In epidemiological settings such as those found in Morocco, QFT-GIT is more sensitive than the TST for active TB diagnosis in children. Combining the TST and QFT-GIT would be useful for the diagnosis of active TB in children, in combination with clinical, radiological and laboratory data.
Mu EW, Lewin JM, Stevenson ML, Meehan SA, Carucci JA, Gareau DS
Show All Authors

Use of Digitally Stained Multimodal Confocal Mosaic Images to Screen for Nonmelanoma Skin Cancer

JAMA DERMATOLOGY 2016 DEC; 152(12):1335-1341
IMPORTANCE Confocal microscopy has the potential to provide rapid bedside pathologic analysis, but clinical adoption has been limited in part by the need for physician retraining to interpret grayscale images. Digitally stained confocal mosaics (DSCMs) mimic the colors of routine histologic specimens and may increase adaptability of this technology. OBJECTIVE To evaluate the accuracy and precision of 3 physicians using DSCMs before and after training to detect basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in Mohs micrographic surgery fresh-tissue specimens. DESIGN This retrospective study used 133 DSCMs from 64 Mohs tissue excisions, which included clear margins, residual BCC, or residual SCC. Discarded tissue from Mohs surgical excisions from the dermatologic surgery units at Memorial Sloan Kettering Cancer Center and Oregon Health & Science University were collected for confocal imaging from 2006 to 2011. Final data analysis and interpretation took place between 2014 and 2016. Two Mohs surgeons and a Mohs fellow, who were blinded to the correlating gold standard frozen section diagnoses, independently reviewed the DSCMs for residual nonmelanoma skin cancer (NMSC) before and after a brief training session (about 5 minutes). The 2 assessments were separated by a 6-month washout period. MAIN OUTCOMES AND MEASURES Diagnostic accuracywas characterized by sensitivity and specificity of detecting NMSC using DSCMs vs standard frozen histopathologic specimens. The diagnostic precision was calculated based on interobserver agreement and. scores. Paired 2-sample t tests were used for comparative means analyses before and after training. RESULTS The average respective sensitivities and specificities of detecting NMSC were 90% (95% CI, 89%-91%) and 79% (95% CI, 52%-100%) before training and 99% (95% CI, 99%-99%) (P = .001) and 93% (95% CI, 90%-96%) (P = .18) after training; for BCC, they were 83% (95% CI, 59%-100%) and 92% (95% CI, 81%-100%) before training and 98% (95% CI, 98%-98%) (P = .18) and 97% (95% CI, 95%-100%) (P = .15) after training; for SCC, they were 73% (95% CI, 65%-81%) and 89% (95% CI, 72%-100%) before training and 100% (P = .004) and 98% (95% CI, 95%-100%) (P = .21) after training. The pretraining interobserver agreement was 72% (kappa = 0.58), and the posttraining interobserver agreement was 98% (kappa = 0.97) (P = .04). CONCLUSIONS AND RELEVANCE Diagnostic use of DSCMs shows promising correlation to frozen histologic analysis, but image quality was affected by variations in image contrast and mosaic-stitching artifact. With training, physicians were able to read DSCMs with significantly improved accuracy and precision to detect NMSC.
Taylor's law (TL) asserts that the variance in a species' population density is a power-law function of its mean population density: log(variance)=a+bxlog(mean). TL is widely verified. We show here that empirical time series of density of the Hokkaido gray-sided vole, Myodes rufocanus, sampled 1962-1992 at 85 locations, satisfied temporal and spatial forms of TL. The slopes (b +/- standard error) of the temporal and spatial TL were estimated to be 1.613 +/- 0.141 and 1.430 +/- 0.132, respectively. A previously verified autoregressive Gompertz model of the dynamics of these populations generated time series of density which reproduced the form of temporal and spatial TLs, but with slopes that were significantly steeper than the slopes estimated from data. The density-dependent components of the Gompertz model were essential for the temporal TL. Adding to the Gompertz model assumptions that populations with higher mean density have reduced variance of density-independent perturbations and that density-independent perturbations are spatially correlated among populations yielded simulated time series that satisfactorily reproduced the slopes from data. The slopes (b +/- standard error) of the enhanced simulations were 1.619 +/- 0.199 for temporal TL and 1.575 +/- 0.204 for spatial TL.