bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the 4‐Substituted Pyridine Ligand L′ on both the Conformation and Spectroscopic Properties of the (2,2′‐Biquinoline‐κN1,κN1′)tricarbonyl(pyridine‐κN1)rhenium(1+) Complex ([Re(CO)3‐(bqui)(py)]+) and Its Derivatives [Re(CO)3(L)(L′)]+ (L = 2,2′‐Biquinoline and 3,3′‐(Ethane‐1,2‐diyl)‐2,2′‐biquinoline)
Authors: Moya Sergio A. , Guerrero Juan , Rodriguez‐Nieto Felipe J. , Wolcan Ezequiel , Féliz Mario R. , Baggio Ricardo F. , Garland María T. 
Published: November 2005

AbstractA series of new rhenium(I) complexes of the type [ReI(CO)3(L)(L′)]n+ (L = 2,2′‐biquinoline (bqui) or 3,3′‐(ethane‐1,2‐diyl)‐2,2′‐biquinoline (CH2CN2)bqui); L′ = CF3SO$\rm{_3^ - }$, pyridine (py), or 4‐substituted pyridine (HOpy, Bzpy, or NCpy); n = 0 or 1) were prepared and characterized by FT‐IR, 1H‐NMR, UV/VIS and emission spectroscopy, luminescence lifetimes, and cyclic voltammetry. The pseudo‐octahedral facial configuration was established by X‐ray single‐crystal diffraction analysis of two complexes and by a FT‐IR study of all complexes. The [Re(CO)3(bqui)(Bzpy)](CF3SO3) complex crystallizes in the form of two mirror isomers arising from the conformational mobility of the biquinoline ligand. A correlation between the metal‐to‐ligand charge‐transfer (MLCT) emission maxima and the σ+ Hammett parameter was established for the complexes of the bqui series, while such correlation was not observed for the complexes of the (CH2CH2)bqui series. No correlation between oxidation potentials and the Hammett parameters was established. The results were rationalized in function of the effect of the 4‐substituted pyridine ligand on the octahedral distortion and conformational characteristic of the complexes. The 1H‐NMR data confirmed these results.
Four 6H‐Dibenzo[b,d]pyran‐6‐one Derivatives Produced by the Endophyte Cephalosporium acremonium IFB‐E007
Authors: Zhang Hua‐Wei , Huang Wu‐Yang , Song Yong‐Chun , Chen Jing‐Rong , Tan Ren‐Xiang 
Published: November 2005

AbstractTwo novel 6H‐dibenzo[b,d]pyran‐6‐one derivatives, graphislactone G (1) and graphislactone H (2), besides graphislactone A (3) and alternariol monomethyl ether (4) were isolated from the CHCl3/MeOH 1 : 1 extract of the solid‐substrate culture of Cephalosporium acremonium IFB‐E007, an endophytic fungus in Trachelospermum jasminoides (Lindl.) Lem. The structures of compounds 1 and 2 were unambiguously established as 2‐chloro‐7‐hydroxy‐3,9‐dimethoxy‐1‐methyl‐6H‐dibenzo[b,d]pyran‐6‐one and 7‐hydroxy‐3,4,9‐trimethoxy‐1‐methyl‐6H‐dibenzo[b,d]pyran‐6‐one, respectively, by a combination of spectroscopic analyses. Compound 1 was unique in its bearing a Cl‐atom. Anticancer tests showed that compounds 1–4 had pronounced activities against SW1116 cell with IC50 values of 21, 12, 8.5, and 14 μg ml−1, respectively.
Design and Synthesis of Novel Artemisinin‐Like Ozonides with Antischistosomal Activity
Authors: Yang Zhong‐Shun , Wu Wen‐Min , Li Ying , Wu Yu‐Lin 
Published: November 2005

AbstractTo develop new drugs for prevention and treatment of schistosomiasis, a series of novel artemisinin‐like ozonides 10 were synthesized via a facile three‐step procedure starting with the degraded product of artemisinin (Scheme). The Criegee ozonolysis reaction of the unsaturated lactone intermediates 14 is the key step which provided the target molecules 10. The in vivo pharmacological results suggested that this type of artemisinin analogues exhibited moderate antischistosomal activity (Table).
New Phenolic Components from Daphne giraldii
Authors: Liao Shang‐Gao , Zhang Bang‐Le , Wu Yan , Yue Jian‐Min 
Published: November 2005

AbstractTwo new bis‐coumarins, namely daphnogitin (1), daphnogirin (2), and a flavan‐3‐ol derivative, 5‐O‐methylafzelechin (3), together with eleven known compounds, daphnetoxin, 1,2‐dihydrodaphnetoxin, daphnetin, daphnoretin, daphneticin, isodaphneticin, trans‐2,3‐dihydro‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐(hydroxymethyl)‐9H‐pyrano[2,3‐f]‐1,4‐benzodioxin‐9‐one (= demethoxyisodaphneticin; 4b), (+)‐pinoresinol, acuminatin, (−)‐dihydrosesamin, and isosalicifoline, were isolated from the leaves and stems of Daphne giraldii. Compound 4b was isolated for the first time as a natural product, and 1,2‐dihydrodaphnetoxin, daphneticin, isodaphneticin, (+)‐pinoresinol, acuminatin, (−)‐dihydrosesamin, and isosalicifoline were isolated for the first time from Daphne giraldii. The structures of the three new compounds were elucidated by spectroscopic analysis.
Synthesis of Substituted Pyrrolo[3,4‐a]carbazoles
Authors: Bleile Michaela , Wagner Trixie , Otto Hans‐Hartwig 
Published: November 2005

AbstractThe cycloaddition between N‐protected 3‐{1‐[(trimethylsilyl)oxy]ethenyl}‐1H‐indoles and substituted maleimides (= 1H‐pyrrole‐2,5‐diones) yielded substituted pyrrolo[3,4‐a]carbazole derivatives bearing an additional succinimide (= pyrrolidine‐2,5‐dione) moiety either at C(5a) or C(10b) depending on the type of the protection group at the indole N‐atom. Derivatives substituted at C(10b) were isolated when the protection group, Me3Si or Boc (tBuOCO), was eliminated during the reaction (Schemes 2 and 3), whereas a substitution at C(5a) was observed when an electron‐withdrawing group, Tos (4‐MeC6H4SO2) or pivaloyl (Me3CCO), was not eliminated (Scheme 1). Complex results were found in reactions between 1‐(trimethylsilyl)‐3‐{1‐[(trimethylsilyl)oxy]ethenyl}‐1H‐indole, in contrast to formerly reported results (Scheme 3). Some derivatives of 1H,5H‐[1,2,4]triazolo[1′,2 : 1,2]pyridazino[3,4‐b]indole‐1,3(2H)‐dione were obtained from reactions with 4‐phenyl‐3H‐1,2,4‐triazole‐3,5(4H)‐dione (Scheme 2). All structures were established by spectroscopic data, by calculations, and one representative structure was confirmed by an X‐ray crystallographic analysis (Fig.). Finally, the formation of the different structure types was discussed, and compared with similar reactions reported in the literature.
Spiro‐biflavonoids from Larix olgensisHenry var. koreanaNakai
Authors: Yang Bao‐Hua , Zhang Wei‐Dong , Liu Run‐Hui , Tan Chang‐Heng , Li Ting‐Zhao , Zhang Chuan , Xu Xi‐Ke , Su Juan 
Published: November 2005

AbstractFour new spiro‐biflavonoids, named olgensisinols A–D (1–4), along with a known one, vitisinol (5), were isolated from the stem bark of Larix olgensis Henry var. koreana Nakai. Their structures were established on the basis of spectroscopic analysis and molecular‐model studies.
Spontaneous Aminoacylation of a RNA Sequence Containing a 3′‐Terminal 2′‐Thioadenosine
Authors: Porcher Sébastien , Meyyappan Muthuppalaniappan , Pitsch Stefan 
Published: November 2005

AbstractWe report the synthesis of a modified 8mer RNA sequence, (C‐C‐C‐C‐A‐C‐C‐(2′‐thio)A)‐RNA 5′‐(dihydrogen phosphate) (9) containing a 3′‐terminal 2′‐thioadenosine (Schemes 2 and 3), and its spontaneous and site‐specific aminoacylation with the weakly activated amino acid thioester HPheSPh (12). This reaction, designed in analogy to the ‘native chemical ligation’ of oligopeptides, occurs efficiently in buffered aqueous solutions and under a wide range of conditions (Table). At pH values between 5.0 and 7.4, two products, the 3′‐O‐monoacylated and the 3′‐O,2′‐S‐diacylated RNA sequences 10 and 11 are formed fast and quantitatively (Scheme 4). At pH 7.4 and 37°, the 3′‐O‐monoacylated product 10 is formed as major product in situ by selective hydrolysis of the O,S‐diacylated precursor 11. Additionally, the preparation and isolation of the relevant 3′‐O‐monoacylated product 10 was optimized at pH 5. The here presented concept could be employed for a straightforward aminoacylation of analogously modified tRNAs.
New Resveratrol Oligomers from the Stem Bark of Hopea hainanensis
Authors: Liu Jun Y. , Ye Yong H. , Wang Lei , Shi Da H. , Tan Ren X. 
Published: November 2005

AbstractThree new resveratrol oligomers, hopeahainanphenol (1), neohopeaphenol A (2), and neoisohopeaphenol A (3), were isolated from the stem bark of Hopea hainanensis (Dipterocarpaceae). Their structures were elucidated by in‐depth spectroscopic analyses, including 1D‐ and 2D‐NMR techniques, and by HR‐ESI‐MS. All the three phytochemicals were tested in vitro for acetylcholinesterase (AChE) inhibitory and antitumor activity. The dimeric compound 2, which corresponds to (1S*,6S*,7S*,11bS*)‐1,6,7,11b‐tetrahydro‐1,7‐bis(4‐hydroxyphenyl)‐6‐[(1R*,6R*,7R*,11bR*)‐1,6,7,11b‐tetrahydro‐4,8,10‐trihydroxy‐1,7‐bis(4‐hydroxyphenyl)benzo[6,7]cyclohepta[1,2,3‐cd]benzofuran‐6‐yl]benzo[6,7]cyclohepta[1,2,3‐cd]benzofuran‐4,8,10‐triol, was found to be significantly active against AChE, with an IC50 value of 7.66 ± 0.13 μm.
Functionalised Monocyclic Five‐ to Seven‐Membered exo‐Glycals by Alkynol Cycloisomerisation of Hydroxy Buta‐1,3‐diynes and 1‐Haloalkynols
Authors: Xu Ming , Miao Zhiwei , Bernet Bruno , Vasella Andrea 
Published: November 2005

AbstractBase‐promoted (KOH or MeONa in MeOH, or NaH in THF) cycloisomerisation of partially benzylated, 1‐substituted (R = PhCC, pyridin‐2‐yl, or Br) ald‐1‐ynitols leads to (Z)‐configured five‐, six‐, and seven‐membered exo‐glycals. The reactivity of the ald‐1‐ynitols depends upon their configuration. The ald‐1‐ynitols were derived from 2,3,5‐tri‐O‐benzyl‐D‐ribofuranose 1, and the corresponding, partially O‐benzylated galactose, glucose, and mannose hemiacetals by ethynylation. The hex‐1‐ynitol 2 derived from 1 (61%) was transformed via the 1‐phenylbuta‐1,3‐diyne 3 and the 1‐(pyridin‐2‐yl)acetylene 5 into the five‐membered exo‐glycals 4 and 6 (in 66 and 72% yields, resp., from 2). The analoguous ethynylation of 2,3,4,6‐tetra‐O‐benzyl‐D‐galactose 8 was accompanied by elimination of one benzyloxy (BnO) group to the hept‐3‐en‐1‐ynitol 9 (71%), which was transformed into the non‐5‐ene‐1,3‐diynitol 10 and further into the six‐membered exo‐glycal 11 (50% from 9). Addition of Me3SiCCH to the galactose 8 and to the gluco‐ and manno‐analogues 16 and 24 gave epimeric mixtures of the silylated oct‐1‐ynitols (86% of 12L/12D 45 : 55, 94% of 17L/17D 7 : 3, and 86% of 25L/25D 55 : 45), which were separated by flash chromatography, and individually transformed into the corresponding 1‐bromooct‐1‐ynitols. Upon treatment with NaH in THF, only the minor epimers 13L, 18D, and 26D cyclised readily to form the seven‐membered hydroxy exo‐glycals. They were acetylated to the more stable monoacetates 14L, 23D, and 28D (82–89% overall yield). Under the same conditions, the epimers 13D, 18L, and 26L decomposed within 12 h mostly to polar products. The difference of reactivity was rationalised by analysing the consequences of an intramolecular C(3)OH ⋅⋅⋅ −OC(7) H‐bond of the intermediate alkoxides on the orientation of −OC(7) of 13L, 18D, and 26D and its proximity to the ethynyl group.
Dolabellane Diterpenoids from the Higher Plant Aglaia odorata
Authors: Cai Xiang‐Hai , Luo Xiao‐Dong , Zhou Jun , Hao Xiao‐Jiang 
Published: November 2005

AbstractTwo new dolabellane diterpenoids, (1R,3R,7E,11S,12R)‐dolabella‐4(16),7‐diene‐3,18‐diol (1) and (1R,3E,7R,11S,12R)‐dolabella‐3,8(17)‐diene‐7,18‐diol (2), and the known (1R,3E,7E,11S,12R)‐dolabella‐3,7‐dien‐18‐ol (3) were isolated from Aglaia odorata, along with twelve other known compounds. Their structures were elucidated on the basis of spectroscopic data. This is the first time that dolabellane‐type diterpenoids were detected in higher plants.
Fascicularones H–K, Four New Sesquiterpenoids from the Cultured Mycelia of the Fungus Hypholoma fasciculare
Authors: Akasaka Hironari , Shiono Yoshihito 
Published: November 2005

AbstractThe AcOEt extract of Hypholoma fasciculare yielded four new congeners, fascicularones H (4), I (5), J (6), and K (7). All structures were unambiguously established by 1D and 2D NMR and MS data. In a lettuce seedling assay, compounds 4–7 showed radicle elongation.
A New 2H‐Azirin‐3‐amine as a Synthon for 2‐Methylaspartate
Authors: Brun Kathrin A. , Heimgartner Heinz 
Published: November 2005

AbstractThe synthesis of a novel 2,2‐disubstituted 2H‐azirin‐3‐amine 3a as a building block for racemic Asp(2Me) is described. This synthon contains an ester group in the side chain. The reaction of 3a with thiobenzoic acid and the amino acid Z‐Val‐OH yielded the racemic monothiodiamide 10a and the dipeptide 11 as a mixture of diastereoisomers, respectively (Scheme 2). In 11, each of the protecting groups was removed selectively (Scheme 3). First attempts toward the preparation of enantiomerically pure synthons for Asp(2Me) with a chiral auxiliary group in the side chain are described. Synthons 3b with a 1‐(naphthalen‐1‐yl)ethyl ester group and 3c with a menthyl ester group were prepared and reacted with thiobenzoic acid to form monothiodiamides 10b and 10c (Scheme 2). However, the diastereoisomers of the synthons 3b and 3c could not be separated by chromatography.
2‐Hydroxytorularhodin, a New Xanthophyll from the Red Yeast Sporobolomyces coprosmae
Authors: Weber Roland W. S. , Madhour Abderrahim , Anke Heidrun , Mucci Adele , Davoli Paolo 
Published: November 2005

AbstractA new hydroxylated carotenoic acid was isolated from the red yeast Sporobolomyces coprosmae and unambiguously identified as 2‐hydroxytorularhodin (1), i.e., (all‐E)‐3′,4′‐didehydro‐2‐hydroxy‐β,ψ‐caroten‐16′‐oic acid, by application of extensive 1D and 2D NMR techniques (gCOSY, gHSQC, gHMBC, DQS, gTOCSY, and ROESY). Hydroxylation of carotenoids at C(2) is uncommon in nature, very rare in fungi, and unprecedented for torularhodin.
Design and Synthesis of Aminoglycoside Antibiotics to Selectively Target 16S Ribosomal RNA Position 1408
Authors: Pathak Rashmi , Böttger Erik C. , Vasella Andrea 
Published: November 2005

AbstractThe glucopyranosyl moiety (ring I) of paromomycin was modified in a search for novel aminoglycoside antibiotics. The key intermediates were the 4′,6′‐O‐benzylidenated N‐Boc derivative 3 and the azido analogue 18. The bromobenzoates 4 and 19 were prepared by treating the benzylidene acetals 3 and 18, respectively, with N‐bromosuccinimide (NBS), and the diol 8 was obtained by hydrogenolysis of 3. The C(6′)‐deoxy derivative 5 was obtained from 4 by treatment with Bu3SnH. Selective fluorodehydroxylation of 8 gave the fluoro derivative 9. The pseudotrisaccharide 13 was obtained by reductive fragmentaion of the iodo compound 12 obtained from the bromobenzoate 4. The 3′,6′‐anhydro derivative 20 was obtained upon deacetylation of 19. Standard deprotection gave the C(6′)‐deoxy compound 7, the fluoro compound 11, the pseudotrisaccharide 15, and the 3′,6′‐anhydro‐paromomycin 22. As compared to paromomycin, the C(6′)‐deoxy and fluorodeoxy derivatives 7 and 11 showed a lower activity against both wild type 1408A and 1408G mutant ribosomes. A lower activity was also found for the 3′,6′‐anhydro derivative 22 and for the pseudotrisaccharide 15.
Triterpene Saponins from Four Species of the Polygalaceae Family
Authors: Mitaine‐Offer Anne‐Claire , Miyamoto Tomofumi , Jolly Claire , Delaude Clément , Lacaille‐Dubois Marie‐Aleth 
Published: November 2005

AbstractTwelve triterpene saponins were isolated by successive MPLC over silica gel from four species of Polygalaceae: From Polygala ruwenzoriensis, five new saponins 1–5 of which 1–4 as two pairs of (E)/(Z)‐isomers, together with the four known compounds tenuifoline, (E)‐ and (Z)‐senegasaponin b, (E)‐ and (Z)‐senegin II, and polygalasaponin XXVIII, from the genus Carpolobia, one new saponin 6 from C. alba and the known arilloside (11) from C. lutea, and another new triterpene glycoside 7 from Polygala arenaria. Their structures were established mainly by 600‐MHz 2D‐NMR techniques (1H,1H‐COSY, TOCSY, NOESY, HSQC, HMBC) as 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐α‐L‐arabinopyranosyl‐(1 → 4)‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐4‐methoxycinnamoyl]‐β‐D‐fucopyranosyl} ester (1) and its (Z)‐isomer 2, 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐α‐L‐arabinopyranosyl‐(1 → 4)‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D‐fucopyranosyl} ester (3) and its (Z)‐isomer 4, 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐[O‐β‐D‐galactopyranosyl‐(1 → 4)‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐β‐D‐fucopyranosyl] ester (5), 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐α‐L‐arabinopyranosyl‐(1 → 3)‐O‐[β‐D‐galactopyranosyl‐(1 → 4)]‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐O‐[β‐D‐apiofuranosyl‐(1 → 3)]‐4‐O‐acetyl‐β‐D‐fucopyranosyl} ester (6), and 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐β‐D‐galactopyranosyl‐(1 → 4)‐O‐[β‐D‐glucopyranosyl‐(1 → 3)]‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐β‐D‐fucopyranosyl} ester (7) (presenegenin = (2β,3β,4α)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid).
Iodotrimethylsilane‐Accelerated One‐Pot Synthesis of 5‐Unsubstituted 3,4‐Dihydropyrimidin‐2(1H)‐ones: A Novel Procedure for the Biginelli‐Like Cyclocondensation Reaction at Room Temperature
Authors: Sabitha Gowravaram , Reddy Kusuma B. , Srinivas Rangavajjula , Yadav Jillu S. 
Published: November 2005

AbstractA novel Biginelli‐like cyclocondensation reaction is efficiently catalyzed by iodotrimethylsilane (Me3SiI) in MeCN. The reaction proceeds at room temperature by a three‐component one‐pot condensation of ketones with aldehydes and urea to afford 5‐unsubstituted 3,4‐dihydropyrimidin‐2(1H)‐ones in good yields (Scheme 1 and Table).
Novel 1‐D Chains Constructed of Rings Which Include Six Metal Atoms [M2Au4] (M = Ni, Zn) with Aurophilic Interactions: Structure, Magnetic, and Spectral Studies
Authors: Wang Shu‐Ping , Song You , Gao Dong‐Zhao , Li Li‐Cun , Wang Qing‐Mei , Liao Dai‐Zheng , Jiang Zong‐Hui , Yan Shi‐Ping 
Published: November 2005

AbstractTwo novel 1‐D chain complexes of a formal iminomethyl nitroxide radical [M(tpyimo)2]2[Au(CN)2]4 (M = Ni, Zn for 1 and 2, typimo = 4,5‐dihydro‐4,4,5,5‐tetramethyl‐2‐(pyridin‐2‐yl)‐1H‐imidazol‐1‐yloxy), were synthesized and structurally characterized. Both 1‐D chains consist of two kinds of chair‐conformation rings, which include six metal atoms [M2Au4] (M = Ni, Zn), and are connected to each other alternately through aurophilic interactions. On the other hand, [Au(CN)$\rm{_2^ - }$]4 oligomers are also formed through aurophilic interactions, and used as bridges in the 1‐D chains. The magnetic coupling between the NiII ion and the tpyimo radical in 1 is a strong ferromagnetic interaction. Strong ligand‐centered luminescence is observed at room temperature for both complexes.
Chemical modification of SWNT alters in vitro cell‐SWNT interactions
Authors: Nimmagadda Aditya , Thurston Karen , Nollert Matthias U. , McFetridge Peter S. 
Published: November 2005

AbstractSingle‐walled carbon nanotubes (SWNT) have been the focus of considerable attention as a material with extraordinary mechanical and electrical properties. SWNT have been proposed in a number of biomedical applications, including neural, bone, and dental tissue engineering. In these applications, it is clear that surrounding tissues will come into surface contact with SWNT composites, and compatibility between SWNT and host cells must be addressed. This investigation describes the gross physical and chemical effects of different SWNT preparations on in vitro cell viability and metabolic activity. Three different SWNT preparations were analyzed: as purchased (AP‐NT), purified (PUR‐NT), and functionalized with glucosamine (GA‐NT), over concentrations of 0.001–1.0% (wt/vol). With the exception of the lowest SWNT concentrations, increasing concentrations of SWNT resulted in a decrease of cell viability, which was dependent on SWNT preparation. The metabolic activity of 3T3 cells was also dependent on SWNT preparation and concentration. These investigations have shown that these SWNT preparations have significant effects on in vitro cellular function that cannot be attributed to one factor alone, but are more likely the result of several unfavorable interactions. Effects, such as destabilizing the cell membrane, soluble toxic contaminants, and limitations in mass transfer as the SWNT coalesce into sheets, may all play a role in these interactions. Using comprehensive purification processes and modifying the NT‐surface chemistry to introduce functional groups or reduce hydrophobicity or both, these interactions can be significantly improved. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Mechanical stimuli and nutrients regulate rapamycin‐sensitive signaling through distinct mechanisms in skeletal muscle
Authors: Hornberger Troy A. , Chien Shu 
Published: November 2005

AbstractThe mammalian target of rapamycin (mTOR) has been identified as a growth factor and nutrient‐sensitive molecule that controls the translational machinery and cell growth. Rapamycin‐sensitive (RS) signaling events have also been shown to be necessary for mechanical load‐induced growth of skeletal muscle, but the mechanisms involved in the mechanical activation of RS signaling are not known. The finding that mechanical stimuli induce nutrient uptake in skeletal muscle raises the possibility that mechanically induced RS signaling is mediated via a nutrient‐dependent mechanism. To investigate this hypothesis, skeletal muscles (ex vivo) were stimulated with nutrients or intermittent mechanical stretch and the phosphorylation of p70S6k [P‐p70(389)], PKB [P‐PKB], mTOR [P‐mTOR(2481)], and p38 [P‐p38] was assessed. In comparison to vehicle‐treated controls, both nutrient and mechanical stimuli induced P‐p70(389), neither stimulus altered P‐PKB or P‐mTOR(2481), and only mechanical stimuli induced P‐p38. The nutrient and mechanically induced increase in P‐p70(389) was blocked by rapamycin, but only nutrient‐induced signaling to P‐p70(389) was blocked by wortmannin. Furthermore, the mechanically induced increase in P‐p70(389) was not impaired by the removal of exogenous nutrients. Taken together, these results indicate that exogenous nutrients are not required for mechanically induced RS signaling and that nutrient and mechanical stimuli activate RS signaling through distinct upstream mechanisms. J. Cell. Biochem. 97: 1207–1216, 2006. © 2005 Wiley‐Liss, Inc.
siRNA binding proteins of microglial cells: PKR is an unanticipated ligand
Authors: Zhang Zhiren , Weinschenk Toni , Guo Ketai , Schluesener Hermann J. 
Published: November 2005

AbstractSmall interfering RNA (siRNA), double‐stranded RNA (dsRNA) 21–23 nucleotides (nt) long with two nt 3′ overhangs, has been shown to mediate powerful sequence‐specific gene silence in mammalian cells through RNA interference (RNAi). Due to its high efficiency and high specificity siRNA has been used as a powerful post genomic tool and a potent therapeutic candidate. However, there is still a lot to learn about the mobility of siRNA inside cells and the cellular factors that might interfere with the specificity and activity of siRNA. Microglia are the brain's effector cells of the innate immune system and suitable targets in the development of novel therapeutic strategies. Here, we show the cellular uptake and intracellular distribution of siRNA in murine microglial N9 cells. siRNA was internalized by microglial N9 cells without transfection reagent and mainly localized to the endosomes However, no significant gene silencing effects were observed. Its cellular uptake and cellular distribution pattern were similar with that of a same length single stranded DNA (ssDNA). Further, cellular binding proteins of siRNA were purified and identified by mass spectrometry. Negative control siRNA and siRNA targeted to β‐actin were used in this part of experiment. Most of the siRNA binding proteins for negative control siRNA and siRNA targeted to β‐actin were dsRNA‐binding proteins, such as dsRNA‐dependent protein kinase R (PKR). Furthermore, both control siRNA and siRNA targeted to β‐actin activated PKR in N9 cells, which suggest that siRNA might cause off‐target effects through activation of PKR. J. Cell. Biochem. 97: 1217–1229, 2006. © 2005 Wiley‐Liss, Inc.