Unusual electron-dense dome associates with compound plasmodesmata in the embryo-suspensor of genus Sedum (Crassulaceae)

Plasmodesmata ensure the continuity of cytoplasm between plant cells and play an important part in the intercellular communication and signal transduction. During the development of the suspensor of both Sedum acre L. and Sedum hispanicum L., changes in the ultrastructure of plasmodesmata and adjoining cytoplasm are observed. Numerous simple plasmodesmata are present in the inner wall of the two-celled embryo separating the basal cell from the apical cell. From the early-globular to the torpedo stage of embryo development, the part of the wall separating the basal cell from the first layer of the chalazal suspensor cells is perforated by unusual, compound plasmodesmata. The role and the sort of transport through these plasmodesmata are discussed.     

<Superscript>1</Superscript>H NMR-based metabolomics combined with HPLC-PDA-MS-SPE-NMR for investigation of standardized <Emphasis Type="Italic">Ginkgo biloba</Emphasis> preparations

Commercial preparations of Ginkgo biloba are very complex mixtures prepared from raw leaf extracts by a series of extraction and prepurification steps. The pharmacological activity is attributed to a number of flavonoid glycosides and unique terpene trilactones (TTLs), with largely uncharacterized pharmacological profiles on targets involved in neurological disorders. It is therefore important to complement existing targeted analytical methods for analysis of Ginkgo biloba preparations with alternative technology platforms for their comprehensive and global characterization. In this work, ¹H NMR-based metabolomics and hyphenation of high-performance liquid chromatography, photo-diode array detection, mass spectrometry, solid-phase extraction, and nuclear magnetic resonance spectroscopy (HPLC-PDA-MS-SPE-NMR) were used for investigation of 16 commercially available preparations of Ginkgo biloba. The standardized extracts originated from Denmark, Italy, Sweden, and United Kingdom, and the results show that ¹H NMR spectra allow simultaneous assessment of the content as well as identity of flavonoid glycosides and TTLs based on a very simple sample-preparation procedure consisting of extraction, evaporation and reconstitution in acetone-d ₆. Unexpected or unwanted extract constituents were also easily identified in the ¹H NMR spectra, which contrasts traditional methods that depend on UV absorption or MS ionizability and usually require availability of reference standards. Automated integration of ¹H NMR spectral segments (buckets or bins of 0.02 ppm width) provides relative distribution plots of TTLs based on their H-12 resonances. The present study shows that ¹H NMR-based metabolomics is an attractive method for non-selective and comprehensive analysis of Ginkgo extracts.     

Species Used for Drug Testing Reveal Different Inhibition Susceptibility for 17beta-Hydroxysteroid Dehydrogenase Type 1

Steroid-related cancers can be treated by inhibitors of steroid metabolism. In searching for new inhibitors of human 17beta-hydroxysteroid dehydrogenase type 1 (17β-HSD 1) for the treatment of breast cancer or endometriosis, novel substances based on 15-substituted estrone were validated. We checked the specificity for different 17β-HSD types and species. Compounds were tested for specificity in vitro not only towards recombinant human 17β-HSD types 1, 2, 4, 5 and 7 but also against 17β-HSD 1 of several other species including marmoset, pig, mouse, and rat. The latter are used in the processes of pharmacophore screening. We present the quantification of inhibitor preferences between human and animal models. Profound differences in the susceptibility to inhibition of steroid conversion among all 17β-HSDs analyzed were observed. Especially, the rodent 17β-HSDs 1 were significantly less sensitive to inhibition compared to the human ortholog, while the most similar inhibition pattern to the human 17β-HSD 1 was obtained with the marmoset enzyme. Molecular docking experiments predicted estrone as the most potent inhibitor. The best performing compound in enzymatic assays was also highly ranked by docking scoring for the human enzyme. However, species-specific prediction of inhibitor performance by molecular docking was not possible. We show that experiments with good candidate compounds would out-select them in the rodent model during preclinical optimization steps. Potentially active human-relevant drugs, therefore, would no longer be further developed. Activity and efficacy screens in heterologous species systems must be evaluated with caution.     

Differentiation of regenerative cells in the midgut epithelium of Epilachna cf nylanderi (Mulsant 1850) (Insecta, Coleoptera, Coccinellidae)

Differentiation of regenerative cells in the midgut epithelium of Epilachna cf nylanderi (Mulsant 1850) (Insecta, Coleoptera, Coccinellidae), a consumer of the Ni-hyperaccumulator Berkheya coddii (Asteracae) from South Africa, has been monitored and described. Adult specimens in various developmental phases were studied with the use of light microscopy and transmission electron microscopy. All degenerated epithelial cells are replaced by newly differentiated cells. They originate from regenerative cells which act as stem cells in the midgut epithelium. Just after pupal-adult transformation, the midgut epithelium of E. nylanderi is composed of columnar epithelial cells and isolated regenerative cells distributed among them. The regenerative cells proliferate intensively and form regenerative cell groups. In each regenerative cell group the majority of cells differentiate into new epithelial cells, while some of them still act as stem cells and persist as a reservoir of cells capable for proliferation and differentiation. Because this species is an obligate monophage of plants which accumulate nickel, proliferation and differentiation of midgut stem cells follow degeneration intensively and in a typical manner.     

Ramipril affects hydrogen sulfide generation in mouse liver and kidney

Hydrogen sulfide (H2S) is a modulator of various physiological and pathological processes in the cardiovascular and nervous system and plays an important role in the regulation of gastrointestinal tract, liver and kidney function. The effect of the pleiotropic action of the tissue specific angiotensin-converting enzyme inhibitor (ACEI), ramipril, exceeds renin-angiotensin aldosterone system (RAAS) blockade and involves different biological mechanisms. The aim of the study is to assess the influence of ramipril on H2S production in mouse liver and kidneys. Thirty mice (CBA) of both sexes were given intraperitoneal injections of ramipril solutions--0.125 mg (5 mg/kg--group D1) and 0.25 mg (10 mg/kg--group D2) for 5 consecutive days at the same time of the day (10:30 am). The control group received physiological saline in portions of the same volume--0.2 ml. The measurements of the tissue concentration of H2S were performed using the modified spectrophotometric method of Siegel. There was a significant rise in the tissue concentration of H2S [microg/g] in livers of group D1 (2.70 +/- 0.02 vs 2.81 +/- 0.06; P = 0.03) and group D2 (2.70 +/- 0.02 vs 2.98 +/- 0.03; P < 0.001) and a significant decrease of H2S kidney tissue concentration in group D1 (3.35 +/- 0.06 vs 3.15 +/- 0.07; P = 0.02) and in group D2 (3.35 +/- 0.06 vs 2.89 +/- 0.03; P < 0.001). Our results show that ACEI ramipril affects hydrogen sulfide generation in mouse liver and kidneys.     

Chitosan pyrolysis and adsorption properties of chitosan and its carbonizate

Chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), ¹³C-nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and elemental analysis (EA). The thin chitosan films obtained by the casting method were heated in vacuum from room temperature to 600 °C. The progress of thermal degradation and carbonization process was monitored by FTIR spectroscopy in a vacuum cell, which allows the elimination of the influence of atmospheric humidity on the chitosan and carbonizate properties. The adsorption of water on the degassed chitosan and its carbonizate as well the oxidation process was also investigated by FTIR spectroscopy. The surface morphology of initial chitosan and obtained carbonaceous material was observed using atomic force microscopy (AFM). Detailed characterization of raw material and carbonization conditions is necessary for tailoring reproducible adsorbent properties.     

Synthetic bastadins modify the activity of ryanodine receptors in cultured cerebellar granule cells

Although the interactions of several natural bastadins with the RyR1 isoform of the ryanodine receptor in sarcoplasmic reticulum has been described, their structure-dependent interference with the RyR2 isoform, mainly expressed in cardiac muscle and brain neurons, has not been studied. In this work, we examined calcium transients induced by natural bastadin 10 and several synthetic bastadins in cultured cerebellar granule cells known to contain RyR2. The fluorescent calcium indicator fluo-3 and confocal microscopy were used to evaluate changes in the intracellular Ca(2+) concentration (Ca(i)), and the involvement of ryanodine receptors was assessed using pharmacological tools. Our results demonstrate that apart from the inactive BAST218F6 (a bisdebromo analogue of bastadin 10), synthetic bastadin 5, and synthetic analogues BAST217B, BAST240 and BAST268 (at concentrations >20 microM) increased Ca(i) in a concentration-dependent, ryanodine- and FK-506-sensitive way, with a potency significantly exceeding that of 20 mM caffeine. Moreover, the same active bastadins at a concentration of 5 muM in the presence of ryanodine prevented a thapsigargin-induced increase in Ca(i). These results indicate that bastadins, acting in a structure-dependent manner, modify the activity of RyR2 in primary neuronal culture and provide new information about structure-related pharmacological properties of bastadins.     

Casein kinases phosphorylate multiple residues spanning the entire hnRNP K length

Heterogeneous Nuclear Ribonucleoprotein K (hnRNP K) is an RNA/DNA-binding protein involved in many processes that regulate gene expression. K protein's pleiotropic action reflects the diversity of its molecular interactions. Many of these interactions have been shown to be regulated by phosphorylation. K protein contains more than seventy potential phosphorylation sites. We used an integrated approach of mass spectrometry and computer analysis to explore patterns of K protein phosphorylation. We found that in vitro a single kinase can phosphorylate K protein on multiple sites spanning the entire length of the protein, including residues contained within the RNA/DNA-binding domains. 2-D gel electrophoresis of K protein purified from cells identified 5-8 spots. Mass spectrometry of K protein isolated from proliferating cells and from cells under oxidative stress revealed the same pattern of phosphopeptides. The structural implications of phosphorylation are discussed.