Understanding the Potential Role of Sirtuin 2 on Aging: Consequences of SIRT2.3 Overexpression in Senescence

Sirtuin 2 (SIRT2) has been associated to aging and age-related pathologies. Specifically, an age-dependent accumulation of isoform 3 of SIRT2 in the CNS has been demonstrated; however, no study has addressed the behavioral or molecular consequences that this could have on aging. In the present study, we have designed an adeno-associated virus vector (AAV-CAG-Sirt2.3-eGFP) for the overexpression of SIRT2.3 in the hippocampus of 2 month-old SAMR1 and SAMP8 mice. Our results show that the specific overexpression of this isoform does not induce significant behavioral or molecular effects at short or long term in the control strain. Only a tendency towards a worsening in the performance in acquisition phase of the Morris Water Maze was found in SAMP8 mice, together with a significant increase in the pro-inflammatory cytokine Il-1β. These results suggest that the age-related increase of SIRT2.3 found in the brain is not responsible for induction or prevention of senescence. Nevertheless, in combination with other risk factors, it could contribute to the progression of age-related processes. Understanding the specific role of SIRT2 on aging and the underlying molecular mechanisms is essential to design new and more successful therapies for the treatment of age-related diseases.     

Immune Dysfunction Associated with Abnormal Bone Marrow-Derived Mesenchymal Stroma Cells in Senescence Accelerated Mice

Senescence accelerated mice (SAM) are a group of mice that show aging-related diseases, and SAM prone 10 (SAMP10) show spontaneous brain atrophy and defects in learning and memory. Our previous report showed that the thymus and the percentage of T lymphocytes are abnormal in the SAMP10, but it was unclear whether the bone marrow-derived mesenchymal stroma cells (BMMSCs) were abnormal, and whether they played an important role in regenerative medicine. We thus compared BMMSCs from SAMP10 and their control, SAM-resistant (SAMR1), in terms of cell cycle, oxidative stress, and the expression of PI3K and mitogen-activated protein kinase (MAPK). Our cell cycle analysis showed that cell cycle arrest occurred in the G0/G1 phase in the SAMP10. We also found increased reactive oxygen stress and decreased PI3K and MAPK on the BMMSCs. These results suggested the BMMSCs were abnormal in SAMP10, and that this might be related to the immune system dysfunction in these mice.     

β-Fur-2-yl-α-halogenacrylonitrile. IV. Reaktionen von β-Fur-2-yl-α-halogenacrylonitrilen mit Alkoholen und Phenolen

β-Fur-2-yl-α-halogenacrylonitriles. IV. Reactions of β-Fur-2-yl-α-halogenacrylonitriles with Alcohols and Phenols β-Fur-2-yl-α-halogenacrylonitriles 1a – c react with alcohols and phenols to yield β-fur-2-yl-β-alkoxyacrylonitriles and β-fur-2-yl-β-aroxyacrylonitriles 2a – k respectively. With ethylene glycol α-[2-(fur-2-yl)-1, 3-dioxolan-2-yl]acetonitriles 3a, b are formed.     

假单胞菌O-2-2产鼠李糖脂的结构表征及理化性质

利用液相色谱/质谱联用仪分析了铜绿假单胞菌O-2-2以正十八烷为碳源所产鼠李糖脂生物表面活性剂的组成。共检出21种鼠李糖脂的同系物,都由1~2分子的鼠李糖和1~2个含β-羟基的碳链长度为8~12的饱和或不饱和脂肪酸构成;主要组分为α-L-吡喃鼠李糖苷-β-羟基癸酰-β-羟基癸酸和2-O-α-L-吡喃鼠李糖苷-α-L-吡喃鼠李糖苷-β-羟基癸酰-β-羟基癸酸。该糖脂类生物表面活性剂可将水的表面张力降至28·6mN/m,临界胶束浓度为1·3×10-4mol/L,在120℃加热4h或者在ρ(NaCl)=100g/L或ρ(CaCl2)=20g/L的盐溶液中仍能保持表面活性。     

Choline Acetyltransferase Induces the Functional Regeneration of the Salivary Gland in Aging SAMP1/Kl -/- Mice

Salivary gland dysfunction induces salivary flow reduction and a dry mouth, and commonly involves oral dysfunction, tooth structure deterioration, and infection through reduced salivation. This study aimed to investigate the impact of aging on the salivary gland by a metabolomics approach in an extensive aging mouse model, SAMP1/Klotho -/- mice. We found that the salivary secretion of SAMP1/Klotho -/- mice was dramatically decreased compared with that of SAMP1/Klotho WT (+/+) mice. Metabolomics profiling analysis showed that the level of acetylcholine was significantly decreased in SAMP1/Klotho -/- mice, although the corresponding levels of acetylcholine precursors, acetyl-CoA and choline, increased. Interestingly, the mRNA and protein expression of choline acetyltransferase (ChAT), which is responsible for catalyzing acetylcholine synthesis, was significantly decreased in SAMP1/Klotho -/- mice. The overexpression of ChAT induced the expression of salivary gland functional markers (α–amylase, ZO-1, and Aqua5) in primary cultured salivary gland cells from SAMP1/Klotho +/+ and -/- mice. In an in vivo study, adeno-associated virus (AAV)-ChAT transduction significantly increased saliva secretion compared with the control in SAMP1/Klotho -/- mice. These results suggest that the dysfunction in acetylcholine biosynthesis induced by ChAT reduction may cause impaired salivary gland function     

β-Fur-2-yl-α-halogenacrylonitrile. VII. Reaktionen von β-(5-Brom-fur-2-yl)-α-bromacrylonitril mit Mercaptan,Thioharnstoff und Thioharnstoffderivaten

β-Fur-2-yl-α-halogenacrylonitriles. VII. Reactions of β-(5-Bromo-fur-2-yl)-α-bromoacrylonitriles with Mercaptans, Thiourea and Thiourea Derivatives β-(5-Bromo-fur-2-yl)-α-bromoacrylonitrile 1 reacts with ethylmercaptan to yield β-(5-bromo-fur-2-yl) β-ethylthioacrylonitrile 3 . With thiourea β,β′-thio-bis[β-(5-bromo-fur-2-yl)]-acrylonitrile 2 is formed. The pyrimidines 4 and 5 have been prepared by the reaction of 1 with s-methylthiourea and 2-aminothiazole, respectively. The structure of the new compounds were determined by means of x-ray analysis, ¹H-n.m.r., ¹³C-n.m.r. and mass-spectroscopy.     

产气荚膜梭菌α-β_2-β_1融合基因的构建及表达

目的构建产气荚膜梭菌α-β2-β1融合蛋白基因表达载体,并对表达产物进行鉴定。方法利用PCR技术,从含α毒素基因的质粒pXCPA02中扩增出α毒素基因,经NcoⅠ酶切,回收0·95kb的α基因片段,再与经NcoⅠ酶切并含融合基因β1-β2的质粒pXETB1B2连接,获得重组质粒pXETAB2B1,经NcoⅠ、BamHⅠ和EcoRⅠ酶切鉴定,并对其表达产物进行SDS-PAGE和Western blot分析。结果重组质粒pXETAB2B1含有α-β2-β1融合基因。表达产物相对分子质量约为95000,并可被特异性抗体识别。结论已获得高效表达α-β2-β1的重组菌株。     

Wear behaviour of α- and α/β-SiAlON ceramics stabilized with Nd2O3 and Y2O3

α- and α/β-SiAlON compositions, doped with Y₂O₃ or Nd₂O₃, were densified by gas pressure sintering (GPS). The wear and mechanical properties of the materials were investigated and compared to β-Si₃N₄ materials. Microstructure evolution and its change with composition as well as the influence of the microstructural changes on the mechanical and tribological properties were reported. Wear tests were performed using a tribometer with ball-on-plate geometry in reciprocating sliding contact under dry condition. It was observed that α/β-SiAlON compositions, doped with Y₂O₃, have better wear properties in comparison to α-SiAlON and β-Si₃N₄ samples. Field emission scanning electron microscopy (FESEM) was used to analyse the worn surfaces after wear tests. The results showed that α/β-SiAlON and β-Si₃N₄ materials have different wear behaviour.     

Reaktionen von β-Chlorvinylaldehyden. V [1]. Zur Bildung von 2,2′-Thiopyrylotrimethinfarbsalzen aus 2-(α-Formylalkyliden)-2H-thiopyranen

Reactions of β-Chlorovinylaldehydes. V. The Formation of 2,2′-Thiopyrylocyanine Dyes from 2-(α-Formylalkylidene)-2H-thipyranes Substituted β-chlorocrotonaldehydes react with Na₂S · 9H₂O to form 2-(α-formyl-alkylidene)-2H-thiopyranes 1 . The corresponding thiopyrylium salts 2 which are easily available from 1 and strong acids exist in the enolic form (2-β-hydroxyvinyl-thiopyrylium salts). They are converted at room temperature in methanol solution to dark green compounds, which are identified as 2,2′-thiopyrylotrimethincyanine dyes 3 . The mechanism of formation of compounds 3 is discussed.     

Zur Auffindung von α-, β- und γ-Dehydrotocopherol in Weizenkeimöl mittels HPLC und GC/MS - ein Beitrag zur Analytik der Tocopherole

Finding of α-, β- and γ-Dehydrotocopherol in Wheat Germ Oil by HPLC and GC/MS - a Contribution to Tocopherol Analysis Fractions of β-tocotrienol/γ-tocopherol isolated from commercial wheat germ oils by preparative TLC were separated once more by HPLC. Three dehydrotocopherols (α-, β-and γ-) were found and identified by GC/MS. HPLC-retention data for plastochromanol-8 in these and corresponding fractions of Latex (Hevea brasiliensis) could be ascertained. The hypothetic 5,7-dimethyltocotrienol could not be found neither in the equivalent fractions of wheat germ oil and Latex nor in those of rude palm oil.     

A Synthetic MUC1 Glycopeptide Bearing βGalNAc‐Thr as a Tn Antigen Isomer Induces the Production of Antibodies against Tumor Cells

This study presents the synthesis of the novel protected O‐glycosylated amino acid derivatives 1 and 2 , containing βGalNAc‐SerOBn and βGalNAc‐ThrOBn units, respectively, as mimetics of the natural Tn antigen (αGalNAc‐Ser/Thr), along with the solid‐phase assembly of the glycopeptides NHAcSer‐Ala‐Pro‐Asp‐Thr[αGalNAc]‐Arg‐Pro‐Ala‐Pro‐Gly‐BSA ( 3 ‐BSA) and NHAcSer‐Ala‐Pro‐Asp‐Thr[βGalNAc]‐Arg‐Pro‐Ala‐Pro‐Gly‐BSA ( 4 ‐BSA), bearing αGalNAc‐Thr or βGalNAc‐Thr units, respectively, as mimetics of MUC1 tumor mucin glycoproteins. According to ELISA tests, immunizations of mice with βGalNAc‐glycopeptide 4 ‐BSA induced higher sera titers (1:320 000) than immunizations with αGalNAc‐glycopeptide 3 ‐BSA (1:40 000). Likewise, flow cytometry assays showed higher capacity of the obtained anti‐glycopeptide 4 ‐BSA antibodies to recognize MCF‐7 tumor cells. Cross‐recognition between immunopurified anti‐βGalNAc antibodies and αGalNAc‐glycopeptide and vice versa was also verified. Lastly, molecular dynamics simulations and surface plasmon resonance (SPR) showed that βGalNAc‐glycopeptide 4 can interact with a model antitumor monoclonal antibody (SM3). Taken together, these data highlight the improved immunogenicity of the unnatural glycopeptide 4 ‐BSA, bearing βGalNAc‐Thr as Tn antigen isomer.     

r-5-(α-Halogenbenzyl)-3, t-4-diaryl-c-4-hydroxy-oxazolidin-2-one als Ringtautomere von α-(Arylaminocarbonyloxy)-β-halogen-dihydrochalkonen

r-5-(α-Halogenobenzyl)-3, t-4-diaryl-c-4-hydroxy-oxazolidin-2-ones as Ring Tautomers of α-(N-Arylaminocarbonyloxy)-β-halogeno-dihydrochalcones The reaction of chalcone halogenohydrins ( 1–3 ) with arylisocyanates does not stop at the stage of the α-arylaminocarbonyloxy-β-halogeno-dihydrochalcones ( 7 ), but the cyclic urethanes 4–6 are formed. Compound 7h was synthesized independently. The structure and stereochemistry of 4–6 and 7h were determined by ¹³C n.m.r. spectroscopy.     

Partialsynthesen von Cardenoliden und Cardenolid-Analogen. I. α,β- und β,γ-ungesättigte Lactonring-methylierte Cardenolide

Partial Syntheses of Cardenolides and Cardenolide Analogues. I. α,β- and β,γ-Unsaturated Lactone Ring-Methylated Cardenolides Base-catalyzed methylation of digitoxigenin 1a with methyl iodide and sodium hydride in DMF leads to the α,β-unsaturated cardenolides 2–5 and, after rearrangement of the CC-double bond, to the β,γ-unsaturated cardenolides 6 and 7 . Opening of the lactone ring results in the formation of 8 . Allylic oxidation of 4b affords the 14,21-epoxide 10 . Only the 22-methyl derivative 4a and its 3-O-tridigitoxoside 4d show strong biological effectivity, whereas methylation at 21R- or 21S-position results in considerable loss in activity.     

Studies of the Ramberg-Bäcklund Rearrangement. Part I. Rearrangement of α-Bromo-β-Keto- and α-Bromo-α-Carbethoxy-Sulphones

α-Bromosulphones, carrying negative substituents (keto or carbethoxy-groups) next to the bromine atom, undergo the Ramberg-Bäcklund rearrangement and give α,β-unsaturated ketones and esters. β-Disulphones are converted into α, β-unsaturated sulphones under these conditions.     

Synthesen von β-Fur-2-yl-α-halogenacrylonitrilen

Syntheses of β-Fur-2-yl-α-halogenacrylonitriles Syntheses of β-fur-2-yl-α-halogenacrylonitriles 2a–f by Wittig-olefination of furfurales, Hunsdiecker-reaction of β-(5-nitro-fur-2-yl)-α-cyanoacrylic acid 3 , halogenation of β-fur-2-yl acrylonitriles and reaction of furfurales with β-azido-α-halogen-γ-methoxy-Δ^α,β-crotonolactones 9 are described.     

Enantioselective Cascade Biocatalysis for Deracemization of Racemic β-Amino Alcohols to Enantiopure (S)-β-Amino Alcohols by Employing Cyclohexylamine Oxidase and ω-Transaminase

Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg⁻¹ protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L⁻¹) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.     

Absolute Configuration of β- and α-Asymmetric Carbons within β-O-4-Structures in Hardwood Lignin

In this study, we investigated the proportion of erythro- and threo-forms of β-O-4-ether structures and their enantiomeric compositions in hardwood lignin by applying the ozonation method to birch wood meal. Optical activity was not substantially observed in either the erythronic or threonic acids obtained as the ozonation products of β-O-4-structures in birch wood meal. The proportions of the four stereoisomeric forms {(αS,βR)-erythro, (αR,βR)-threo, (αS,βS)-threo, and (αR,βS)-erythro forms} were estimated to be 37-38%, 13-14%, 12-13%, and 36-37% based on the yields of erythronic and threonic acids, and on their optical activities. The proportions suggest that the entire components of β-O-4-ether structures in birch wood lignin have R- and S-configurations at the β-carbon in approximately the same quantities {(βR)-β-O-4-structure: (βS)-β-O-4-structure = 50–52:48–50}; i.e., that the β-ether structures are essentially racemic. This estimation implies that, during lignin biosynthesis, an equal number of enantiomeric forms of β-O-4-bonded quinone methides were formed by radical coupling reactions.     

Memory effect of locally ordered α-phase in the melting and phase transformation behavior of β-isotactic polypropylene

Structural changes in β-isotactic polypropylene (β-iPP) during the heating were studied by means of differential scanning calorimetry and real-time in situ X-ray diffraction using a synchrotron source. Crystalline phase transformation and the memory effect caused by residual nuclei of α-iPP were observed during the heating of β-iPP. The memory effect observed in β-iPP during heating and crystallization is believed to be due to the existence of locally ordered α-from in the melt. The effect of local α-form order was probed by studying the behavior under heating of samples with a range of thermal histories. Samples were heated above the equilibrium melting temperature of iPP to remove all residual local order and the memory effect associated with this local order. The samples crystallized isothermally at different temperatures exhibited a significantly different melting and phase transformation behavior during heating. β-iPP is found to be an excellent material for the study of polymorphism, phase transformations, and characteristic memory effects in semicrystalline polymers.     

Organic Fluorine Compounds. Part XLII. The Reaction of Amides of α-Bromoacids with Potassium Fluoride

The reaction of potassium fluoride with α-bromocarboxylic acid anilides, substituted in the α- or β-position, causes dehydrohalogenation and gives α, β-unsaturated anilides. Long-chain α,α′-dibromodicarboxylic acid (>C₈) anilides give in the same reaction essentially α,αprime;-di-fluorocarboxylic acid anilides.     

Synthesis of Some Benzoquinolines and Benzacridines

2-Arylidene-3,4-dihydro-1(2H)-naphthalenones 1 react with ethyl cyanoacetate in presence of ammonium acetate to give 4-aryl-7:8-benzo-3-cyano-1,2,3,4,5,6-hexahydro-2-oxoquinoline 2 , 4-aryl-7:8-benzo-3-cyano-2-oxo-1,2,5,6-tetrahydroquinoline 3 and an oily product 4 . Hydrolysis and decarboxylation of 4 gave β-aryl-β-(2-α-tetralonyl)propanoic acid 5 . Thermolysis of 4 gave 2 and 3 . Compounds 2 and 3 were also obtained by treatment of 1 with cyanoacetamide using piperidine as a catalyst. Condensation of 1 with diethyl malonate, cyclohexanone, and α-tetralone in presence of ammonium acetate afforded 4-aryl-7:8-benzo-1,2,3,4,5,6-hexahydro-2-oxoquinoline 8 , 9-aryl-3:4-benzo-1,2,6,7,8,10-hexahydroacridine 9 , and 9-aryl-3:4,5:6-dibenzo-1,2,7,8-tetrahydroacridine 10 , respectively.