bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wingless signaling in a large insect, the blowfly Lucilia sericata: A beautiful example of evolutionary developmental biology
Authors: Mellenthin Katja , Fahmy Khalid , Ali Reda A. , Hunding Axel , Da Rocha Sol , Baumgartner Stefan 
Published: October 2005

AbstractBlowflies are the primary facultative agent in causing myiasis of domestic sheep in the whole world and, at the same time, it is an important tool for forensic medicine. Surprisingly, and in contrast to its importance, almost no data regarding the embryology and molecular markers are known for this insect. In this report, we present a detailed description of the blowfly Lucilia sericata embryogenesis and of imaginal disc development. The embryogenesis of Lucilia strongly resembles that of Drosophila, despite their apparent size difference. Moreover, imaginal disc development appears to be equally well conserved. Through cloning, expression, and functional studies, we show that the Lucilia Wingless (Wg) protein is highly conserved between the two species. We further show that parasegments are established in Lucilia, however, engrailed expression shows a more dynamic expression pattern than expected in comparison to Drosophila. Over‐expression of Lucilia Wingless in Drosophila shows wingless‐like wing phenotypes, suggesting that Lucilia Wingless blocks the signalling activity of Drosophila Wingless. Upon injection of wg dsRNA, we observe a “lawn of denticle” phenotype, closely resembling that of Drosophila. Due to the large size of the insect, the distance over which Wingless exerts signalling activity is up to three times larger than in Drosophila, yet the consequences are very similar. Our data demonstrate long‐range wingless signaling mechanisms adapted for patterning large domains of naked cuticle and suggest signaling properties of Lucilia Wingless that are distinct from those of Drosophila Wingless. Developmental Dynamics 235:347–360, 2006. © 2005 Wiley‐Liss, Inc.
Modeling past and future alpine permafrost distribution in the Colorado Front Range
Authors: Janke Jason R. 
Published: October 2005

AbstractRock glaciers, a feature associated with at least discontinuous permafrost, provide important topoclimatic information. Active and inactive rock glaciers can be used to model current permafrost distribution. Relict rock glacier locations provide paleoclimatic information to infer past conditions. Future warmer climates could cause permafrost zones to shrink and initiate slope instability hazards such as debris flows or rockslides, thus modeling change remains imperative. This research examines potential past and future permafrost distribution in the Colorado Front Range by calibrating an existing permafrost model using a standard adiabatic rate for mountains (0·5 °C per 100 m) for a 4 °C range of cooler and warmer temperatures. According to the model, permafrost currently covers about 12 per cent (326·1 km2) of the entire study area (2721·5 km2). In a 4 °C cooler climate 73·7 per cent (2004·4 km2) of the study area could be covered by permafrost, whereas in a 4°C warmer climate almost no permafrost would be found. Permafrost would be reduced severely by 93·9 per cent (a loss of 306·2 km2) in a 2·0 °C warmer climate; however, permafrost will likely respond slowly to change. Relict rock glacier distribution indicates that mean annual air temperature (MAAT) was once at least some 3·0 to 4·0 °C cooler during the Pleistocene, with permafrost extending some 600–700 m lower than today. The model is effective at identifying temperature sensitive areas for future monitoring; however, other feedback mechanisms such as precipitation are neglected. Copyright © 2005 John Wiley & Sons, Ltd.
The form and function of headwater streams based on field and modeling investigations in the southern Appalachian Mountains
Authors: Adams Rebecca Kavage , Spotila James A. 
Published: October 2005

AbstractHeadwater streams drain the majority of most landscapes, yet less is known about their morphology and sediment transport processes than for lowland rivers. We have studied headwater channel form, discharge and erosive power in the humid, moderate‐relief Valley and Ridge and Blue Ridge provinces of the Appalachian Mountains. Field observations from nine headwater (<2 km2drainage area), mixed bedrock–alluvial channels in a variety of boundary conditions demonstrate variation with respect to slope‐area channel initiation, basic morphology, slope distribution, hydraulic geometry, substrate grain size and role of woody debris. These channels display only some of the typical downstream trends expected of larger, lowland rivers. Variations are controlled mainly by differences in bedrock resistance, from the formation level down to short‐wavelength, outcrop‐scale variations. Hydrologic modeling on these ungauged channels estimates the recurrence of channel‐filling discharge and its ability to erode the channel bed. Two‐year recurrence discharge is generally larger and closer to bankfull height in the Valley and Ridge, due to low soil infiltration capacity. Discharge that fills the channel to its surveyed bankfull form is variable, generally exceeding two‐year flows at small drainage areas (<0·5 km2) and being exceeded by them at greater drainage areas. This suggests bankfull is not controlled by the same recurrence storm throughout a channel or physiographic region. Stream power and relative competence are also variable. These heterogeneities contrast relations observed in larger streams and illustrate the sensitivity of headwater channels to local knickpoints of resistant bedrock and armoring of channels by influx of coarse debris from hillslopes. The general lack of predictable trends or functional relationships among hydraulic variables and the close coupling of channel form and function with local boundary conditions indicate that headwater streams pose a significant challenge to landscape evolution modeling. Copyright © 2005 John Wiley & Sons, Ltd.
Fine allelotyping of Erbb2‐induced mammary tumors in mice reveals multiple discontinuous candidate regions of tumor‐suppressor loci
Authors: Cool Marc , Depault François , Jolicoeur Paul 
Published: October 2005

AbstractLoss of heterozygosity (LOH) at human chromosome bands 1p32–36 and 10q23–26 is frequent in various human tumors, including breast cancers, and is thought to reflect the loss of tumor‐suppressor genes (TSGs). To map such genes, high‐resolution LOH analysis was performed on 93 Erbb2‐induced mammary tumors from (BALB/c × C57BL/6) F1 MMTV/Erbb2 transgenic mice. A panel of 24 microsatellite markers specific to the region of mouse chr4, homologous to human 1p31–36, and 16 markers specific to the mouse chr19 region, homologous to human 10q23–26 were used. In addition, lower‐density mapping was performed on the remaining portion of mouse chr4 [homologous to human 9p13, 9p21–24, 9q21–22, 9q31–34 (12 markers)] and chr19 [homologous to 9q21, 9p24, 11q12–13 (9 markers)]. Several distinct, discrete, and discontinuous LOH regions flanked by areas of heterozygosity were identified, 22 on chr4 and 14 on chr19. Among these, 13 were mapped in the region of homology with human 1p31–36 (between D4Mit153 and D4Mit254) and 9 in the region of homology with human 10q23–26 (between D19Mit46 and D19Mit6). Although several LOH loci span a large interval, many are relatively short (1–4 Mb), and a few span an interval of <1 Mb. This allelotyping represents the highest density of LOH loci yet mapped in these chromosomal regions. The presence of numerous LOH regions in alternation with regions of heterozygosity, consistent with mitotic recombination as a mechanism for generating such a mosaic pattern, suggests the presence of several TSGs in these regions and should facilitate their identification. © 2005 Wiley‐Liss, Inc.
Gross SDHB deletions in patients with paraganglioma detected by multiplex PCR: A possible hot spot?
Authors: Cascón Alberto , Montero‐Conde Cristina , Ruiz‐Llorente Sergio , Mercadillo Fátima , Letón Rocío , Rodríguez‐Antona Cristina , Martínez‐Delgado Beatriz , Delgado Manuel , Díez Alberto , Rovira Adela , Díaz José Ángel , Robledo Mercedes 
Published: October 2005

AbstractPheochromocytoma and paraganglioma are rare neuroendocrine tumors that arise in the adrenal medulla and the extra‐adrenal paraganglia, respectively. Inheritance of these tumors is mainly a result of mutations affecting the VHL, RET, NF1, and SDH genes. Germ‐line mutations of the SDH genes have been found to account for nearly 10% of apparently sporadic cases. Nevertheless, alterations other than point mutations have not yet been well characterized. In this study, we investigated the frequency of gross SDH deletions in 24 patients who tested negative for point mutations and had at least one of the recommended features for genetic testing. For this purpose, we used a technique that is easy to implement in the lab to specifically detect gross deletions affecting SDHB, SDHC, and SDHD. We identified 3 heterozygous SDHB deletions (3/24) in 3 independent cases with paraganglioma: 1 whole SDHB deletion and 2 deletions exclusively affecting exon 1. These latter mutations match the unique gross deletion previously reported, indicating this region could be a hot spot for gross SDHB deletions. It seems likely that these alterations can account for a considerable number of both familial and apparently sporadic paraganglioma cases. Although this is the first report describing the presence of gross deletions in patients with apparently sporadic paragangliomas, the extra‐adrenal location of the tumor seems to constitute a determining factor for whether to include these patients in genetic testing for gross deletions in the SDHB gene. © 2005 Wiley‐Liss, Inc.
Synthetic Studies on Coenzyme Q10
Authors: Yu Xiong‐Jie , Chen Fen‐Er , Dai Hui‐Fang , Chen Xu‐Xiang , Kuang Yun‐Yan , Xie Bin 
Published: October 2005

AbstractA practical, highly stereoselective ten‐step synthesis of coenzyme Q10 (1) has been accomplished (overall yield ca. 28%), starting from commercially available 2,3‐dimethoxy‐5‐methylbenzoquinone (Scheme). The introduction of the first side‐chain isoprenyl group with (E)‐configuration (compound 6) was realized by means of a coupling reaction of the aromatic system 3 with oxirane, followed by Swern oxidation and Wittig olefination. The tosyl (Ts) group in the sulfone 9 was selectively removed with sodium naphthalenide in THF to afford 1.
Intramolecular Photocyclization of 2‐Acylphenyl Methacrylates: a Convenient Access to 4,5‐Dihydro‐1,4‐epoxy‐2‐benzoxepin‐3(1H)‐ones (= Benzo[c]‐6,8‐dioxabicyclo[3.2.1]octan‐7‐ones
Authors: Nishio Takehiko , Sakurai Nobuharu , Iba Kaoru , Hamano Yo‐ichi , Sakamoto Masami 
Published: October 2005

AbstractThe photochemical reactions of 2‐acylphenyl methacrylates (= 2‐acylphenyl 2‐methylprop‐2‐enoates) 1 were investigated. Irradiation of 2‐acylphenyl methacrylates 1a–d in MeCN gave the tricyclic lactones 2a–d in good yields, together with a small amount of OCO bond cleavage product, the 2‐acylphenols 3a–d (Scheme 2, Table). The formation of the tricyclic lactones 2 probably follows a mechanism involving a 1,7‐diradical through ζ‐H abstraction (1,8‐H transfer) by the excited carbonyl O‐atom (Scheme 3). Irradiation of 2‐acylphenyl tiglate (= 2‐acylphenyl (2E)‐2‐methylbut‐2‐enoate) 1e and 2‐acylphenyl methacrylates 1g–i, substituted by a MeO group (δ‐H) at the 3,5‐positions of the phenyl group, also gave the tricyclic lactones 2e and 2g–i, but in low yields. On the other hand, no H‐abstraction products were observed on irridation of 2‐(ethoxycarbonyl)phenyl methacrylate 1f, of 2‐acylphenyl methacrylate 1j which is substituted by a Me group (γ‐H) at the 3,5‐positions of the phenyl group, and of 1k with an OH group at the 3‐position of the phenyl group.
Multiflorane Triterpene Esters from the Seeds of Trichosanthes kirilowii
Authors: Wu Tao , Cheng Xue‐Mei , Bligh S. W. Annie , Chou Gui‐Xin , Wang Zheng‐Tao , Bashall Alan , Branford‐White Chris 
Published: October 2005

AbstractTwo new multiflorane triterpene esters, (3α,7β)‐3,7,29‐trihydroxymultiflor‐8‐ene‐3,29‐diyl dibenzoate (2) and (3α)‐3,29‐dihydroxy‐7‐oxomultiflor‐8‐ene‐3,29‐diyl dibenzoate (3) have been isolated from the CHCl3 extract of the seeds of Trichosanthes kirilowii, together with two known compounds, (3α,5α,22E)‐24‐ethylcholesta‐7,22,25(27)‐trien‐3‐ol and darutigenol. The structures of the new compounds were elucidated on the basis of extensive NMR experiments, and by means of an X‐ray crystallographic analysis of 2. A preliminary cytotoxicity assay showed that 2 and 3 are basically inactive against the K562 cell line.
Synthesis and Reactions of a New Cyclobutanethione Derivative
Authors: Mlostoń Grzegorz , Majchrzak Agnieszka , Rutkowska Marzena , Woznicka Marta , Linden Anthony , Heimgartner Heinz 
Published: October 2005

AbstractThe 3,3‐dichloro‐2,2,4,4‐tetramethylcyclobutanethione (4b) was prepared from the parent diketone by successive reaction with PCl5 and Lawesson reagent in pyridine. This new thioketone 4b was transformed into 1‐chlorocyclobutanesulfanyl chloride 5 and chloro 1‐chlorocyclobutyl disulfide 9 by treatment with PCl5 and SCl2, respectively, in chlorinated solvents (Schemes 1 and 2). These products reacted with S‐ and P‐nucleophiles by substitution of Cl− at the S‐atom; e.g., the reaction with 4b yielded the di‐ and trisulfides 6b and 11, respectively. Surprisingly, only pentasulfide 12 was formed in the reaction of 9 with thiobenzophenone (Scheme 3). In contrast to 5 and 9, the corresponding chloro 1‐chlorocyclobutyl trisulfide 13 could not be detected, but reacted immediately with the starting thioketone 4b to give the tetrasulfide 14 (Scheme 4). Oxidation of 4b with 3‐chloroperbenzoic acid (mCPBA) yielded the corresponding thione oxides (= sulfine) 15, which underwent 1,3‐dipolar cycloadditions with thioketones 3a and 4b (Scheme 5). Furthermore, 4b was shown to be a good dipolarophile in reactions with thiocarbonylium methanides (Scheme 6) and iminium ylides (= azomethine ylides; Scheme 7). In the case of phenyl azide, the reaction with 4b gave the symmetrical trithiolane 25 (Scheme 8).
Structures and Absolute Configurations of Three 7,8‐Secolabdane Diterpenes from the Chinese Liverwort Pallavicinia ambigua
Authors: Li Zi‐Jing , Lou Hong‐Xiang , Yu Wen‐Tao , Fan Pei‐Hong , Ren Dong‐Mei , Ma Bin , Ji Mei 
Published: October 2005

AbstractThe known 7,8‐secolabdane type diterpenoids neopallavicinin (1), pallavicinin (2), and 18‐hydroxypallavicinin (3) were isolated from Pallavicinia ambigua, and their structures were determined. The X‐ray crystal structure of 1 was solved, and, in combination with CD and NMR studies, the absolute configurations of 1–3 were established. A possible biogenetic pathway for 1 and 2 from a single labdane precursor is proposed.
para‐Sulfonated Calixarenes Used as Synthetic Receptors for Complexing Photolabile Cholinergic Ligand
Authors: Specht Alexandre , Ziarelli Fabio , Bernard Philippe , Goeldner Maurice , Peng Ling 
Published: October 2005

AbstractThe water‐soluble tetra‐, hexa‐ and octasulfonated calix[4]arenes, calix[6]arenes, and calix[8]arenes 1–3, respectively, were investigated as potential synthetic receptors for photolabile cholinergic ligand A, a photolytic precursor of choline. Ligand A is a bifunctional molecule carrying a photolabile 2‐nitrobenzyl group at one end and a choline moiety at the other end. Results from NMR studies have shown that calixarenes 1–3 form stable 1 : 1 complexes with A, having similar binding potential to that observed with the cholinergic enzymes acetylcholinesterase and butyrylcholinesterase. Further studies have suggested that calix[8]arene forms a ditopic complex by binding concomitantly to both the cationic choline moiety and the aromatic photolabile group of A, whereas calix[4]arene and calix[6]arene form monotopic complexes with A. The ditopic complex between calix[8]arene and A results from mutually induced fitting process, while the monotopic complexes between calix[4]arene and A can be regulated by pH: at neutral pH, calix[4]arene specifically binds the cationic choline moiety, while, at acidic pH, it complexes unselectively both the cationic choline moiety and the aromatic group of A. Our results show that para‐sulfonated calixarenes are versatile artificial receptors which bind in various ways to the bifunctional photolabile cholinergic ligand A, depending on their size, geometry, and state of protonation.
Three New Polyoxypregnane Glycosides from Marsdenia tenacissima
Authors: Deng Jun , Liao Zhixin , Chen Daofeng 
Published: October 2005

AbstractThree new polyoxypregnane glycosides, marsdenosides I–K (1–3), were isolated from the stem of Marsdenia tenacissima. The structures were elucidated on the basis of in‐depth spectroscopic analyses, and by means of chemical evidence. Marsdenoside I (= (3β,5α,11α,12β,14β,17α,20R)‐3‐[(2,6‐dideoxy‐4‐O‐(6‐deoxy‐3‐O‐methyl‐β‐D‐allopyranosyl)‐3‐O‐methyl‐β‐D‐arabino‐hexopyranosyl)oxy]‐8,20 : 11,20‐diepoxypregnane‐12,14‐diol; 1) is the first C21 steroidal glycoside with a rigid cage. Also, the isolation of 1 demonstrated that tenacigenin A (1a) is a true natural product as well, rather than an artifact.
Synthesis of 2′‐O‐[(Triisopropylsilyl)oxy]methyl (= tom)‐Protected Ribonucleoside Phosphoramidites Containing Various Nucleobase Analogues
Authors: Porcher Sébastien , Pitsch Stefan 
Published: October 2005

AbstractThe first results of a study aiming at an efficient preparation of a large variety of 2′‐O‐[(triisopropylsilyl)oxy]methyl(= tom)‐protected ribonucleoside phosphoramidite building blocks containing modified nucleobases are reported. All of the here presented nucleosides have already been incorporated into RNA sequences by several other groups, employing 2′‐O‐tbdms‐ or 2′‐O‐tom‐protected phosphoramidite building blocks (tbdms = (tert‐butyl)dimethylsilyl). We now optimized existing reactions, developed some new and shorter synthetic strategies, and sometimes introduced other nucleobase‐protecting groups. The 2′‐O‐tom, 5′‐O‐(dimethoxytrityl)‐protected ribonucleosides N2‐acetylisocytidine 5, O2‐(diphenylcarbamoyl)‐N6‐isobutyrylisoguanosine 8, N6‐isobutyryl‐N2‐(methoxyacetyl)purine‐2,6‐diamine ribonucleoside (= N8‐isobutyryl‐2‐[(methoxyacetyl)amino]adenosine) 11, 5‐methyluridine 13, and 5,6‐dihydrouridine 15 were prepared by first introducing the nucleobase protecting groups and the dimethoxytrityl group, respectively, followed by the 2′‐O‐tom group (Scheme 1). The other presented 2′‐O‐tom, 5′‐O‐(dimethoxytrityl)‐protected ribonucleosides inosine 17, 1‐methylinosine 18, N6‐isopent‐2‐enyladenosine 21, N6‐methyladenosine 22, N6,N6‐dimethyladenosine 23, 1‐methylguanosine 25, N2‐methylguanosine 27, N2,N2‐dimethylguanosine 29, N6‐(chloroacetyl)‐1‐methyladenosine 32, N6‐{{{(1S,2R)‐2‐{[(tert‐butyl)dimethylsilyl]oxy}‐1‐{[2‐(4‐nitrophenyl)ethoxy]carbonyl}propyl}amino}carbonyl}}adenosine 34 (derived from L‐threonine) and N4‐acetyl‐5‐methylcytidine 36 were prepared by nucleobase transformation reactions from standard, already 2′‐O‐tom‐protected ribonucleosides (Schemes 2–4). Finally, all these nucleosides were transformed into the corresponding phosphoramidites 37–52 (Scheme 5), which are fully compatible with the assembly and deprotection conditions for standard RNA synthesis based on 2′‐O‐tom‐protected monomeric building blocks.
Computational NMR Spectroscopy of Transition‐Metal/Nitroimidazole Complexes: Theoretical Investigation of Potential Radiosensitizers
Authors: Ramalho Teodorico C. , Bühl Michael , Figueroa‐Villar José Daniel , de Alencastro Ricardo Bicca 
Published: October 2005

AbstractThe computed chemical shifts of transition‐metal complexes with dimetridazole (= 1,2‐dimethyl‐5‐nitro‐1H‐imidazole; 1), a prototypical nitro‐imidazole‐based radiosensitizer, are reported at the GIAO‐BP86 and ‐B3LYP levels for BP86/ECP1‐optimized geometries. These complexes comprise [MCl2(1)2] (M = Zn, Pd, Pt), [RuCl2(DMSO)2(1)2], and [Rh2(O2CMe)4(1)2]. Available δ(1H) and δ(15N) values, and Δδ(1H) and Δδ(15N) coordination shifts are well‐reproduced theoretically, provided solvation and relativistic effects are taken into account by means of a polarizable continuum model and suitable methods including spin–orbit (SO) coupling, respectively. These effects are particularly important for the metal‐coordinated N‐atom, where the contributions from solvation and relativity can affect δ(15N) and Δδ(15N) values up to 10–20 ppm. The 195Pt chemical shifts of cis‐ and trans‐[PtCl2(1)2] are well‐reproduced using the zero‐order regular approximation including SO coupling (ZORA‐SO). Predictions are reported for 99Ru and 103Rh chemical shifts, which suggest that these metal centers could be used as additional, sensitive NMR probes in their complexes with nitro‐imidazoles.
Synthesis of New Resorcinarenes Under Alkaline Conditions
Authors: Bourgeois Jean‐Marc , Stoeckli‐Evans Helen 
Published: October 2005

AbstractThe preparation of functionalized resorcinarenes is described. Thus, 2‐nitroresorcinol (= 2‐nitrobenzene‐1,2‐diol), 2‐acetylresorcinol (= 1‐(2,6‐dihydroxyphenyl)ethanone), and 2,6‐dihydroxybenzoic acid were treated with formaldehyde in alkaline medium to give the corresponding resorcinarenes1–3(Scheme 1). This method is also applicable for resorcinol (= benzene‐1,3‐diol) itself, but the yields are poorer. In this case, the molecule formed is the simplest resorcinarene4on which a number of substituents can be inserted between the two OH groups. Thus, bromation of4yields5(Scheme 2). Some properties and conformations of these new products are discussed, and the X‐ray crystal structures of the nitro and bromo compounds1and5, respectively, are presented.
Squadinorlignoside: A Novel 7,9′‐Dinorlignan from the Stems of Annona squamosa
Authors: Yang Yu‐Liang , Chang Fang‐Rong , Wu Yang‐Chang 
Published: October 2005

AbstractTwo new polar lignans, i.e., squadinorlignoside (= 4‐[(1E)‐1‐(hydroxymethyl)‐3‐(4‐hydroxyphenyl)prop‐1‐en‐1‐yl]phenyl β‐D‐glucopyranoside; 1) and (6R,7R,8S)‐7a‐[(β‐D‐glucopyranosyl)oxy]‐1‐methoxyisolariciresinol (2) were isolated from the stems of Annona squamosa, together with eight known lignans and five known neolignans (compounds 3–15; Fig. 1). All of these constituents are reported for the first time from the genus Annona. The structures, absolute configurations, and selected conformational aspects of the new compounds were elucidated spectroscopically. Compound 1 is the first example of a 7,9′‐dinorlignan natural product.
Enantioselective Syntheses and Fragrance Properties of the Four Stereoisomers of Magnolione® (Magnolia Ketone)
Authors: Stang Andrea Quendolin , Helmchen Günter 
Published: October 2005

AbstractEnantioselective total syntheses of the four stereoisomers of the fragrance Magnolione® (1) are described. Key step is a Pd‐catalyzed asymmetric allylic alkylation displaying enantiomer excess of ≥ 99% (Scheme 2). The resultant methyl α‐acetyl‐2‐pentylcyclopent‐2‐ene‐1‐acetate) was subjected to demethoxycarbonylation, carbonyl protection by acetalization, and epoxidation (Schemes 2 and 3). Subsequent Lewis acid catalyzed epoxide/ ketone rearrangement followed by deprotection gave cis/trans mixtures of Magnolione® in 28% overall yield (Scheme 3). The cis/trans isomers were separated by prep. HPLC, and fragrance properties as well as odor threshold values were determined (Table 2).