Multifunctionality of Silicified Nanoshells at Cell Interfaces of <i>Oryza sativa</i>

The mimic and design of artificial nanoshell materials on individual cells have been explored in microbial and mammalian cells, and these synthetic interfacial materials can confer new and unique properties on living cells to resist various environmental stresses. However, no attempts have been made toward chemical nanoencapsulation of higher plant cells. Here, we cultivated rice (<i>Oryza sativa</i>) single cells whose cell walls were silicified identically by mimicking diatom biomineralization. Results show that the silica nanoshell at the cell interface is effective at adsorbing cadmium (Cd²⁺) ions by in situ noninvasive microtest technology to quantitatively measure Cd²⁺ ion fluxes, rapidly sequestering and immobilizing Cd ions in the silicified cell walls with adsorption fluxes 6- to 10-times greater than those of the unsilicified cell walls. This, therefore, confers increased Cd tolerance by inhibiting Cd ion uptake into cells. In addition, using in situ atomic force microscopy to probe cell mechanical properties, the cell walls are remarkably strong by virtue of the material properties of the silica nanoshells that physically protects the cells against mechanical challenges. Chemically silicified cells may have acquired a multifunctionality of co-optimized mechanical protection and heavy metal detoxification by organic–inorganic composite materials of the silicified cell walls

Intraspecific Variation and Phylogenetic Relationships Are Revealed by ITS1 Secondary Structure Analysis and Single-Nucleotide Polymorphism in <i>Ganoderma lucidum</i> - Fig 3

<p><b>DNA Weblogo of the (A) ITS1 and (B) ITS2 regions in strains of <i>Ganoderma lucidum</i>.</b> Regions represent potential nucleotide variance. Major variance regions are enclosed in boxes.</p

Large-scale evaluation of the ITS2 rRNA secondary structure models.

<p>A) <i>Ganoderma lucidum</i> Group 1 with one representative secondary structures of each subgroup. B) <i>Ganoderma lucidum</i> Group 2 with eleven representative secondary structure of each subgroup. C) <i>Ganoderma lucidum</i> Group 3 with seven representative secondary structures of each subgroup. Each of the subgroups of three groups (A1, B1-B11, C1-C7) chooses a sequence as the representative to predict the secondary structure. Differences (mainly in bulges) are indicated with arrows.</p

Molecular phylogeny of the <i>Ganoderma lucidum</i> species used in this study based on the ITS2 rRNA region.

<p>(A) The 50% majority rule consensus tree (Cladogram) from maximum likelihood analyses based on 153 sequences of the ITS2 region. (B) Two groups (1,3 and 2) are identified among <i>Ganoderma lucidum</i> sequences. Group 1 (blue part) and Group 3 as the subgroup formed the same group. Branch support is noted on branches (only for the collapsed branches). Both trees are rooted to <i>Trametes versicolor</i>.</p

Predicted secondary structure models of the ITS1 rRNA molecule of <i>Ganoderma lucidum</i>.

<p>Three helices commonly found in the 2D structure of Groups 2 and 3 are numbered from Helix 1 to Helix 3. Four helices found in the 2D structure of Group 1 are numbered from Helix 1 to Helix 4. All substitutions recorded among three groups of <i>Ganoderma lucidum</i> are mapped on the 2D models.</p

Multiple-alignment of <i>Ganoderma lucidum</i> ITS1 sequences.

<p>A single-nucleotide polymorphism is located at position 180. Cytosines are shaded with light blue, and thymines are shaded with white.</p

Predicted secondary structure models of the ITS2 rRNA molecule of <i>Ganoderma lucidum</i>.

<p>Four helices commonly found in the 2D structure of Groups 1, 2 and 3 are numbered from Helix 1 to Helix 4. All substitutions recorded among three groups of <i>Ganoderma lucidum</i> are mapped on the 2D models.</p

Large-scale evaluation of the ITS1 rRNA secondary structure models.

<p>A) <i>Ganoderma lucidum</i> Group 1 with four representative secondary structures of each subgroup. B) <i>Ganoderma lucidum</i> Group 2 with eight representative secondary structures of each subgroup. C) <i>Ganoderma lucidum</i> Group 3 with five representative secondary structures of each subgroup. Each of the subgroups of three groups (A1-A4, B1-B8, C1-C5) chooses a sequence as the representative to predict the secondary structure. Differences (mainly in bulges) are indicated with arrows.</p

Post-transcriptional Regulation of Keratinocyte Progenitor Cell Expansion, Differentiation and Hair Follicle Regression by <i>miR-22</i>

<div><p>Hair follicles (HF) undergo precisely regulated recurrent cycles of growth, cessation, and rest. The transitions from anagen (growth), to catagen (regression), to telogen (rest) involve a physiological involution of the HF. This process is likely coordinated by a variety of mechanisms including apoptosis and loss of growth factor signaling. However, the precise molecular mechanisms underlying follicle involution after hair keratinocyte differentiation and hair shaft assembly remain poorly understood. Here we demonstrate that a highly conserved microRNA, <i>miR-22</i> is markedly upregulated during catagen and peaks in telogen. Using gain- and loss-of-function approaches <i>in vivo</i>, we find that <i>miR-22</i> overexpression leads to hair loss by promoting anagen-to-catagen transition of the HF, and that deletion of <i>miR-22</i> delays entry to catagen and accelerates the transition from telogen to anagen. Ectopic activation of <i>miR-22</i> results in hair loss due to the repression a hair keratinocyte differentiation program and keratinocyte progenitor expansion, as well as promotion of apoptosis. At the molecular level, we demonstrate that <i>miR-22</i> directly represses numerous transcription factors upstream of phenotypic keratin genes, including <i>Dlx3</i>, <i>Foxn1</i>, and <i>Hoxc13</i>. We conclude that <i>miR-22</i> is a critical post-transcriptional regulator of the hair cycle and may represent a novel target for therapeutic modulation of hair growth.</p></div

Antagonism tests of seven <i>Ganoderma lucidum</i> strains.

<p>The seven <i>Ganoderma lucidum</i> strains are indicated with different abbreviations (RB, YS, 203, DB, TK, JQ, and HZ). Antagonistic streaks are indicated with red arrows.</p