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Fei Mao

Publications and source records attributed to Fei Mao.

10 recordsLinked to original sources
PubMed2025

Epigenetic maps of pearl millet reveal a prominent role for CHH methylation in regulating tissue-specific gene expression.

UNLABELLED: Pearl millet (Pennisetum glaucum) is a major staple food in arid and semi-arid regions of sub-Saharan Africa, India, and South Asia. However, how epigenetic mechanisms regulate tissue-specific gene expression in this crop remains poorly understood. In this study, we profiled multiple epigenetic features in the young panicles and roots of pearl millet using RNA-seq, ATAC-seq, whole-genome bisulfite sequencing, and ChIP-seq (H3K4me3 and H3K36me3). We identified thousands of genes that were differentially expressed between these two tissues. Root-specific genes were enriched for plant hormone signaling, oxidative phosphorylation, and stress responses. Analysis of chromatin accessibility revealed that root-specific accessible chromatin regions (ACRs) were enriched in binding motifs for stress-responsive transcription factors (e.g., NAC, WRKY), whereas ACRs in young panicles were enriched in motifs for developmental regulators (e.g., AP2/ERF). DNA methylation profiling revealed 25,141 tissue-specific differentially methylated regions, with CHH methylation-rather than CG or CHG methylation-showing the strongest tissue specificity. Promoters of root-specific genes had higher levels of CHH methylation compared to those of young panicle-specific genes, suggesting that the roles of CHH methylation in regulating transcription might be tissue dependent. Notably, promoter-associated H3K4me3 marked panicle-specific genes, whereas root-specific expression was primarily linked to chromatin accessibility, suggesting a transcription factor-mediated regulatory mechanism. Together, our findings highlight the distinct epigenetic frameworks governing tissue-specific gene expression in pearl millet and provide valuable insights for advancing the genetic improvement of this crop. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42994-025-00243-2.

CHH methylation↗
PubMed2004

Modulating the redox properties of an osmium-containing metallopolymer through the supporting electrolyte and cross-linking.

Thin films of the perchlorate salt of an [Os(N,N'-alkylated-2,2'-biimidazole3)2+/3+-containing polymer have been formed on planar platinum microelectrodes. The electrochemical response associated with the Os2+/3+ couple occurs at -0.19 V. In aqueous perchlorate media at near-neutral pH the voltammetric response is close to that expected for an electrochemically reversible reaction involving a surface-confined reactant. Chronoamperometry conducted on a microsecond time scale indicates that the film and solution resistances are comparable for low concentrations of supporting electrolyte. However, for LiClO4 concentrations greater than 0.4 M, RFilm contributes less than 25% of the overall cell resistance. These results suggest that when the film is dehydrated and the density of redox centers is increased, electron or hole hopping dominates the rate of homogeneous charge transport through the film. The rate of homogeneous charge transport, characterized by D(CT)1/2Ceff, where DCT is the homogeneous charge transport diffusion coefficient and Ceff is the effective concentration of osmium centers within the film, depends weakly on the concentration of LiClO4 as supporting electrolyte decreasing from (8.1 +/- 0.16) x 10(-9) to (4.7 +/- 0.4) x 10(-9) mol cm(-2) s(-1/2) as the perchlorate concentration increases from 0.1 to 1.0 M. These values are about 2 orders of magnitude lower than those of the chemically cross-linked chloride salt of the polymer. The rate of heterogeneous electron transfer is unusually rapid in this system and increases from (5.2 +/- 0.4) x 10(-3) to (7.8 +/- 0.4) x 10(-3) cm s(-1) on going from 0.1 to 0.4 M LiClO4 before becoming independent of the supporting electrolyte concentration at (9.2 +/- 0.6) x 10(-3) cm s(-1) for [LiClO4] > or = 0.6 M.

Journal Article↗
PubMed2003

Characteristics of a miniature compartment-less glucose-O2 biofuel cell and its operation in a living plant.

We report the temperature, pH, glucose concentration, NaCl concentration, and operating atmosphere dependence of the power output of a compartment-less miniature glucose-O(2) biofuel cell, comprised only of two bioelectrocatalyst-coated carbon fibers, each of 7 micro m diameter and 2 cm length (Mano, N.; Mao, F.; Heller, A. J. Am. Chem. Soc. 2002, 124, 12962). The bioelectrocatalyst of the anode consists of glucose oxidase from Aspergillus niger electrically "wired" by polymer I, having a redox potential of -0.19 V vs Ag/AgCl. That of the cathode consists of bilirubin oxidase from Trachyderma tsunodae "wired" by polymer II having a redox potential of +0.36 V vs Ag/AgCl (Mano, N.; Kim, H.-H.; Zhang, Y.; Heller, A. J. Am. Chem. Soc. 2002, 124, 6480. Mano, N.; Kim, H.-H.; Heller, A. J. Phys. Chem. B 2002, 106, 8842). Implantation of the fibers in the grape leads to an operating biofuel cell producing 2.4 micro W at 0.52 V.

Bioelectric Energy Sources↗
PubMed2003

Long tethers binding redox centers to polymer backbones enhance electron transport in enzyme "Wiring" hydrogels.

A redox hydrogel with an apparent electron diffusion coefficient (D(app)) of (5.8 +/- 0.5) x 10(-)(6) cm(2) s(-)(1) is described. The order of magnitude increase in D(app) relative to previously studied redox hydrogels results from the tethering of redox centers to the backbone of the cross-linked redox polymer backbone through 13 atom spacer arms. The long and flexible tethers allow the redox centers to sweep electrons from large-volume elements and to collect electrons of glucose oxidase efficiently. The spacer arms make the collection of electrons from glucose oxidase so efficient that glucose is electrooxidized already at -0.36 V versus Ag/AgCl, the reversible potential of the redox potential of the FAD/FADH(2) centers of the enzyme at pH 7.2. The limiting current density of 1.15 mA cm(-)(2) is reached at a potential as low as -0.1 V versus Ag/AgCl. The novel redox center of the polymer is a tris-dialkylated N,N'-biimidazole Os(2+/3+) complex. Its redox potential, -0.195 V versus Ag/AgCl, is 0.8 V reducing relative to that of Os(bpy)(2+/3+), its 2,2'-bipyridine analogue.

2,2'-Dipyridyl↗
PubMed2002

A miniature biofuel cell operating in a physiological buffer.

A glucose-O2 biofuel cell, consisting only of two electrocatalyst coated 7-mum diameter, 2-cm long carbon fibers is reported. The cell operated continuously at 0.52 V at 37 degrees C in a physiological buffer solution for a week, producing 1.9 muW during the first and 1.0 muW during the last day, generating in the period 0.9 J of electrical energy while passing a charge of 1.7 C. If a similar dimension zinc fiber were utilized in a battery at 100% current efficiency, only 0.016 C would have been generated.

Bioelectric Energy Sources↗
PubMedDate not supplied

An improved method of region grouping for microcalcification detection in digital mammograms.

A very important issue, namely region grouping, in computer-assisted diagnostic detection of microcalcification clusters (MCC) in digital mammograms is addressed in this work. In the diagnosis of breast cancer, MCC, instead of single and isolated microcalcifications, are considered clinically significant. Grouping individual regions segmented from digital mammograms, therefore, should be a component in an automatic MCC detection system. Actually this component may concern several system modules, such as segmentation, feature extraction, performance estimation aiming at both algorithm optimization and consistent evaluation and ultimately computerized malignancy estimation of calcified lesions. The previous work in the literature used a kernel-based method for region grouping. We proposed a distance-based and dense-to-sparse grouping method. The grouping result should be independent of the size, shape and orientation of real clusters. The application, namely cluster-oriented analysis including an adaptive segmentation method and cluster level feature extraction scheme, is discussed. A preliminary study was performed on a set of 30 full mammograms at 60 microm resolution, containing 40 MCC. The introduction of the cluster level feature extraction and a simple rule-based method reduces false positives from 7.1 to 2.4 per image at the sensitivity of 92.5%. This grouping method provides a solid basis for effective feature extraction-analysis and candidate cluster classification.

Algorithms↗