Evolution of trichome types and its systematic significance in the genus Phlomoides (Lamioideae–Lamiaceae)

Despite a number of recent molecular phylogenetic studies on Phlomoides, in terms of trichome morphology the genus is still among the most poorly studied taxa in the family Lamiaceae. In order to test the utility of trichome characters for delimitation of sections, subsection and species of Phlomoides, we examined trichomes of 64 species representing all recognized sections and subsections using stereomicroscopy and scaning electron microscopy. Two basic types of trichomes could be identified: non‐glandular and glandular. Both trichome types can be simple or branched. The glandular trichomes were sessile, short stalked or long stalked. Different kinds of branched trichomes were observed in most species of P. sect. Phlomoides, i.e. symmetrically stellate, stellate with a central long branch, bi‐ or trifurcate. The species of P. sect. Filipendula were mostly covered by simple trichomes. Moreover, variation in trichome characters appears to have particular value, not only for the classification at sectional or subsectional rank, but also for delimitation of species within each section. For example, all studied species of P. subsect. Fulgentes are characterized by various kinds of stellate trichomes, while the trichome variability in P. subsect. Tetragonae was sufficiently high for species discrimination. An ancestral character state reconstruction was performed in order to investigate the evolution of trichome types and it revealed the following evolutionary trends in trichome characters of Phlomoides: 1) branched trichomes are primitive in Phlomoides as compared to simple ones, 2) long simple non‐glandular trichomes are derived as compared to short simple ones and 3) the presence of stalked glandular trichomes is advanced as compared to subsessile or sessile ones.     

Exosomes and microRNAs: New potential therapeutic candidates in Alzheimer disease therapy

Exosomes are biological nanocarriers which could be involved in a variety of basic physiological events. They exert their effects via targeting their cargos (i.e., DNAs, messenger RNAs, microRNAs [miRNAs], and proteins) to host cells, which led to change behaviors of recipient cells. One of the important aspects of exosomes is the roles of them in disease conditions. Increasing evidence indicated that exosomes are one of the main players in Alzheimer’s disease (AD) pathogenesis. Hence, it seems that these nanocarriers could be used as diagnostic and therapeutic biomarkers in AD treatment. Another important player in AD pathogenesis is miRNA. MiRNAs are short noncoding RNAs which exert their effects as epigenetic regulators. These molecules involved in different stages of AD. Therefore, miRNAs could be used as prognostic, diagnostic, and therapeutic biomarkers in AD. Here, we summarized various roles of exosomes and application of them in AD pathogenesis. Moreover, we highlighted the utilization of miRNAs as a therapeutic option in AD therapy.     

Cultivation and Differentiation Change Nuclear Localization of Chromosome Centromeres in Human Mesenchymal Stem Cells

Chromosome arrangement in the interphase nucleus is not accidental. Strong evidences support that nuclear localization is an important mechanism of epigenetic regulation of gene expression. The purpose of this research was to identify differences in the localization of centromeres of chromosomes 6, 12, 18 and X in human mesenchymal stem cells depending on differentiation and cultivating time. We analyzed centromere positions in more than 4000 nuclei in 19 mesenchymal stem cell cultures before and after prolonged cultivation and after differentiation into osteogenic and adipogenic directions. We found a centromere reposition of HSAX at late passages and after differentiation in osteogenic direction as well as of HSA12 and HSA18 after adipogenic differentiation. The observed changes of the nuclear structure are new nuclear characteristics of the studied cells which may reflect regulatory changes of gene expression during the studied processes.     

Expression of Acyl-lipid △12-desaturase Gene in Prokaryotic and Eukaryotic Cells and Its Effect on Cold Stress Tolerance of Potato

We report the expression profile of acyl-lipid Δ12-desaturase (desA) gene from Synechocystis sp. PCC6803 and its effect on cell membrane lipid composition and cold tolerance in prokaryotic (Escherichia coli) and eukaryotic (Solanum tuberosum) cells. For this purpose, a hybrid of desA and reporter gene encoding thermostable lichenase (licBM3) was constructed and used to transform these cells. The expression of this hybrid gene was measured using qualitative (Petri dish test, electrophoregram and zymogram) and quantitative methods (spectrometry and gas liquid chromatography assays). The maximum level of linoleic acid in the bacterial cells containing hybrid gene was 1.9% of total fatty acids. Cold stress tolerance assays using plant damage index and growth parameters showed that cold tolerance was enhanced in primary transgenic lines because of increased unsaturated fatty acid concentration in their lipids. The greatest content of 18:2 and 18:3 fatty acids in primary transgenic plants was observed for lines 2 (73%) and 3 (41%). Finally, our results showed that desaturase could enhance tolerance to cold stress in potato, and desaturase and lichenase retain their functionality in the structure of the hybrid protein where the enzymatic activity of target gene product was higher than in the case of reporter lichenase gene absence in the construction.     

Epithelial junctions depend on intercellular trans-interactions between the Na,K-ATPase β₁ subunits

N-Glycans of the Na,K-ATPase β₁ subunit are important for intercellular adhesion in epithelia, suggesting that epithelial junctions depend on N-glycan-mediated interactions between the β₁ subunits of neighboring cells. The level of co-immunoprecipitation of the endogenous β₁ subunit with various YFP-linked β₁ subunits expressed in Madin-Darby canine kidney cells was used to assess β₁-β₁ interactions. The amount of co-precipitated endogenous dog β₁ was greater with dog YFP-β₁ than with rat YFP-β₁, showing that amino acid-mediated interactions are important for β₁-β₁ binding. Co-precipitation of β₁ was also less with the unglycosylated YFP-β₁ than with glycosylated YFP-β_1, indicating a role for N-glycans. Mixing cells expressing dog YFP-β₁ with non-transfected cells increased the amount of co-precipitated β₁, confirming the presence of intercellular (YFP-β₁)-β₁ complexes. Accordingly, disruption of intercellular junctions decreased the amount of co-precipitated β₁ subunits. The decrease in β₁ co-precipitation both with rat YFP-β₁ and unglycosylated YFP-β₁ was associated with decreased detergent stability of junctional proteins and increased paracellular permeability. Reducing N-glycan branching by specific inhibitors increased (YFP-β₁)-β₁ co-precipitation and strengthened intercellular junctions. Therefore, interactions between the β₁ subunits of neighboring cells maintain integrity of intercellular junctions, and alterations in the β₁ subunit N-glycan structure can regulate stability and tightness of intercellular junctions.     

Molecular Mechanisms for CFIm-Mediated Regulation of mRNA Alternative Polyadenylation

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Septin Dynamics Are Essential for Exocytosis

Septins are a family of 14 cytoskeletal proteins that dynamically form hetero-oligomers and organize membrane microdomains for protein complexes. The previously reported interactions with SNARE proteins suggested the involvement of septins in exocytosis. However, the contradictory results of up- or down-regulation of septin-5 in various cells and mouse models or septin-4 in mice suggested either an inhibitory or a stimulatory role for these septins in exocytosis. The involvement of the ubiquitously expressed septin-2 or general septin polymerization in exocytosis has not been explored to date. Here, by nano-LC with tandem MS and immunoblot analyses of the septin-2 interactome in mouse brain, we identified not only SNARE proteins but also Munc-18-1 (stabilizes assembled SNARE complexes), N-ethylmaleimide-sensitive factor (NSF) (disassembles SNARE complexes after each membrane fusion event), and the chaperones Hsc70 and synucleins (maintain functional conformation of SNARE proteins after complex disassembly). Importantly, α-soluble NSF attachment protein (SNAP), the adaptor protein that mediates NSF binding to the SNARE complex, did not interact with septin-2, indicating that septins undergo reorganization during each exocytosis cycle. Partial depletion of septin-2 by siRNA or impairment of septin dynamics by forchlorfenuron inhibited constitutive and stimulated exocytosis of secreted and transmembrane proteins in various cell types. Forchlorfenuron impaired the interaction between SNAP-25 and its chaperone Hsc70, decreasing SNAP-25 levels in cultured neuroendocrine cells, and inhibited both spontaneous and stimulated acetylcholine secretion in mouse motor neurons. The results demonstrate a stimulatory role of septin-2 and the dynamic reorganization of septin oligomers in exocytosis.     

Polarized membrane distribution of potassium-dependent ion pumps in epithelial cells: Different roles of the <Emphasis Type="Italic">N</Emphasis>-glycans of their <Emphasis Type="Italic">β</Emphasis> subunits

The Na,K-ATPases and the H,K-ATPases are two potassium-dependent homologous heterodimeric P₂-type pumps that catalyze active transport of Na⁺ in exchange for K⁺ (Na,K-ATPase) or H⁺ in exchange for K⁺ (H,K-ATPase). The ubiquitous Na,K-ATPase maintains intracellular ion balance and membrane potential. The gastric H,K-ATPase is responsible for acid secretion by the parietal cell of the stomach. Both pumps consist of a catalytic α-subunit and a glycosylated β-subunit that is obligatory for normal pump maturation and trafficking. Individual N-glycans linked to the β-subunits of the Na,K-ATPase and H,K-ATPase are important for stable membrane integration of their respective α subunits, folding, stability, subunit assembly, and enzymatic activity of the pumps. They are also essential for the quality control of unassembled β-subunits that results in either the exit of the subunits from the ER or their ER retention and subsequent degradation. Overall, the importance of N-glycans for the␣maturation and quality control of the H,K-ATPase is greater than that of the Na,K-ATPase. The roles of individual N-glycans of the β-subunits in the post-ER trafficking, membrane targeting and plasma membrane retention of the Na,K-ATPase and H,K-ATPase are different. The Na,K-ATPase β ₁-subunit is the major β-subunit isoform in cells with lateral location of the pump. All three N-glycans of the Na,K-ATPase β ₁-subunit are important for the lateral membrane retention of the pump due to glycan-mediated interaction between the β ₁-subunits of the two neighboring cells in the cell monolayer and cytosolic linkage of the α-subunit to the cytoskeleton. This intercellular β ₁–β ₁ interaction is also important for formation of cell–cell contacts. In contrast, the N-glycans unique to the Na,K-ATPase β ₂-subunit,which has up to eight N-glycosylation sites, contain apical sorting information. This is consistent with the apical location of the Na,K-ATPase in normal and malignant epithelial cells with high abundance of the β ₂-subunit. Similarly, all seven N-glycans of the gastric H,K-ATPase β-subunit determine apical sorting of this subunit. Supported in part by NIH grants DK46917, DK58333, D53642, and USVA     

Salivary Nickel and Chromium Levels in Orthodontic Patients with and Without Periodontitis: a Preliminary Historical Cohort Study

Many periodontal patients may need orthodontic treatment. Alterations in oral environment particularly the reduction of pH in periodontal patients could affect metal ion release from orthodontic appliances. However, there is no study on metal ion release in periodontal patients. The aim of this preliminary study was to comparatively evaluate, for the first time, salivary levels of nickel and chromium in periodontal patients (versus healthy controls) under orthodontic treatment for 2 months. In this in vivo study, 40 subjects were evaluated. Patient selection and standardization of orthodontic treatment protocols were prospectively designed and performed. Two groups of n = 20 each (control: healthy orthodontic patients, cohort: orthodontic patients with periodontitis) underwent similar protocols of fixed orthodontic treatment for 2 months. After 2 months, salivary nickel and chromium concentrations of the case and cohort groups were measured using inductively coupled plasma mass spectrometry (ICP-MS). The values were compared between the two groups using t test. There were 10 men and 10 women in each group. The mean age of patients was 34.6 ± 3.6 years old. The salivary level of nickel was 338.2 ± 235.5 ng/ml and 182.8 ± 116.5 ng/ml in the cohort and control groups, respectively (P = 0.0118). The salivary level of chromium was 7.4 ± 3.15 ng/ml in the cohort and 6.35 ± 2.39 ng/ml in the control group (P = 0.2214). Salivary level of nickel might be considerably higher in periodontal patients undergoing 2 months of orthodontic treatment compared to orthodontic patients with healthy gingivae.