bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Characterization and Photophysical Properties of Novel Dinuclear Silver(I) and Mononuclear Palladium(II) Complexes with 1,2‐Bis[(anthracen‐9‐ylmethyl)amino]ethane
Authors: Zhang Guo‐qi , Yang Guo‐qiang , Yang Lan‐ying , Chen Qing‐qi , Ma Jin‐Shi 
Published: May 2005

AbstractSilver(I) (3) and palladium(II) (4) complexes of 1,2‐bis[(anthracen‐9‐ylmethyl)amino]ethane have been synthesized and structurally characterized. X‐ray crystal structure analysis reveals that compound 3 exists as a dinuclear tris(ligand) complex with formula [Ag2(2)3]·2NO3, in which each silver center is three‐coordinate to form a slightly distorted planar‐trigonal geometry with three nitrogen donors originating from two distinct ligands. Compound 4, on the other hand, is a mononuclear bis(ligand) complex with formula [Pd(2)2]·2OAc, in which the palladium center is four‐coordinate with four nitrogen donors originating from two distinct ligands to form a square‐planar geometry. In crystals of both 3 and 4 strong intermolecular edge‐to‐face C–H···π packing interactions are observed, which contribute to stabilize the crystalline solid. Studies of the photophysical properties of these compounds (3, 4, and ligand 2) show apparent fluorescence quenching effect by introduction of metal ions and likely “excimer” emission of anthracene in the crystalline solid. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Di‐2‐pyridyl Ketone Oxime in Zinc Chemistry: Inverse 12‐Metallacrown‐4 Complexes and Cationic Pentanuclear Clusters
Authors: Alexiou Maria , Katsoulakou Eugenia , Dendrinou‐Samara Catherine , Raptopoulou Catherine P. , Psycharis Vassilis , Manessi‐Zoupa Evy , Perlepes Spyros P. , Kessissoglou Dimitris P. 
Published: May 2005

AbstractThe use of di‐2‐pyridyl ketone oxime (Hpko)/X– “blends” (X– = PhCO2–, N3–, NCO–, acac–, NCS–) in zinc chemistry yields neutral tetranuclear and cationic pentanuclear clusters. Various synthetic procedures have led to the synthesis of compounds [Zn4(OH)2(O2CPh)2(pko)4]·3MeCN (1·3MeCN), [Zn4(OH)2(N3)2(pko)4]·4DMF (2·4DMF), [Zn4(OH)2(NCO)2(pko)4]·3DMF·H2O (3·3DMF·H2O), [Zn4(OH)2(acac)2(pko)4]·4CH2Cl2 (4·4CH2Cl2), [Zn5Cl2(pko)6][ZnCl(NCS)3]·2.5H2O·1.5MeOH (5·2.5H2O·1.5MeOH) and [Zn5(NCS)2(pko)6(MeOH)][Zn(NCS)4]·2.5H2O·MeOH (6·2.5H2O·MeOH). The structures of the six complexes have been determined by single‐crystal X‐ray crystallography. The tetranuclear molecules of 1–4 lie on a crystallographic inversion centre and have an inverse 12‐metallacrown‐4 topology. Two triply bridging hydroxides are accommodated in the centre of the metallacrown ring. The pko– ligands form a propeller configuration that imposes absolute stereoisomerism with Λ and Δ chirality. Two metal ions are in distorted O2N4 octahedral environments, whereas the rest are in severely distorted tetrahedral or trigonal bipyramidal environments. The five Zn ions of the cations of 5 and 6 are held together by six pko– ligands which adopt three different coordination modes; the chloro (5) and isothiocyanato (6) ligands are terminal. The five Zn ions define two nearly equilateral triangles sharing a common apex, and the novel Zn5 topology can be described as two “collapsed” 9‐metallacrown‐3 structures sharing a common Zn apex. Besides the pentanuclear cations, the structures of 5 and 6 contain slightly distorted tetrahedral [ZnCl(NCS)3]2– and [Zn(NCS)4]2– ions, respectively, with the isothiocyanato ligands binding the metal ion in a virtually linear fashion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Structures, Electronic States and Electroluminescent Properties of a Series of CuI Complexes
Authors: Yang Li , Feng Ji‐Kang , Ren Ai‐Min , Zhang Ming , Ma Yu‐Guang , Liu Xiao‐Dong 
Published: May 2005

AbstractA series of new mixed‐ligand copper(I) complexes [Cu(NN)POP]BF4, where NN = 1,10‐phenanthroline (phen; 1a), 2,9‐dimethyl‐phen (DMphen; 1b), 4,7‐diphenyl‐phen (DPpehn; 1c) and 2,2'‐bipyridine (bpy; 2a), have been synthesized. Density functional theory (DFT) was applied to study the ground‐ and excited‐state properties of these copper(I) complexes. The electronic structure variation is obtained by changing the substituted positions on the phenanthroline ligand. A time‐dependent‐DFT approach (TDDFT) was used to interpret the absorption and emission spectra in this system based on the optimized geometries at the B3LYP/LANL2DZ and CIS/LANL2DZ levels of theory, respectively. The results show that the lowest‐energy excitations of all complexes are dominated by dπ(Cu)→π*(phen) or bpy (MLCT) excitations. In particular, the lowest triplet state (T1) corresponds to an excitation from the HOMO to the LUMO in all considered complexes, and emissions occur from T1, assigned to 3MLCT. Steric effects exerted by the pendent groups at the 2‐ and 9‐positions of the phenanthroline ligands increase the HOMO–LUMO gaps and thus lead to a blue‐shift of both absorption and emission spectra and effectively prevent structural relaxation in the MLCT state, which may narrow the energy gap between the excited and ground states and therefore increase nonradiative decay. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
N‐Bonded Monosilanols: Synthesis and Characterization of ArN(SiMe3)SiMe2Cl and ArN(SiMe3)SiMe2OH (Ar = C6H5, 2,6‐Me2C6H3,2,6‐iPr2C6H3)
Authors: Chandrasekhar Vadapalli , Boomishankar Ramamoorthy , Azhakar Ramachandran , Gopal Kandasamy , Steiner Alexander , Zacchini Stefano 
Published: May 2005

AbstractBy the use of aniline and the sterically hindered aromatic primary amines, 2,6‐Me2C6H3NH2 and 2,6‐iPr2C6H3NH2, N‐bonded monochlorosilanes, ArN(SiMe3)SiMe2Cl [Ar = C6H5 (1a), Ar = 2,6‐Me2C6H3 (1b) and Ar = 2,6‐iPr2C6H3 (1c)] have been prepared by a sequential deprotonation at the nitrogen followed by reaction with silyl chlorides. Hydrolysis of the N‐bonded monochlorosilanes afforded the N‐bonded monosilanols ArN(SiMe3)SiMe2OH [Ar = C6H5 (2a), Ar = 2,6‐Me2C6H3 (2b) and Ar = 2,6‐iPr2C6H3 (2c)]. The X‐ray crystal structure of 1c reveals a positional disorder of the Cl and CH3 substituents on silicon. The X‐ray crystal structure of 2c shows that it is involved in an intermolecular O–H···O hydrogen bonding in the solid state to afford a dimeric structure containing the O2H2 ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Low‐Valent Titanium–Pentafulvene Complexes – Formation of Dinuclear Titanium–Nitrogen Complexes
Authors: Scherer Axel , Kollak Kay , Lützen Arne , Friedemann Marion , Haase Detlev , Saak Wolfgang , Beckhaus Rüdiger 
Published: May 2005

AbstractIn a late stage of production Equation (2) on p. 1006 of the print version[1] was inadvertently replaced by a copy of Equation (3); the electronic version is free of this error. The correct Equation (2) is shown below.
Hyrtiosins A–E, Five New Scalarane Sesterterpenes from the South China Sea Sponge Hyrtios erecta
Authors: Yu Zhi‐Guo , Bi Kai‐Shun , Guo Yue‐Wei 
Published: May 2005

AbstractFive new scalarane sesterterpenes, hyrtiosins A–E (1–5), together with three previously reported sesterterpenes, 25‐dehydroxy‐12‐epi‐scalarin (6), 12‐epi‐scalarin (7) and heteronemin (9), were isolated from the South China Sea sponge Hyrtios erecta. Their structures were determined on the basis of extensive NMR studies and high‐resolution MS measurements.
Asymmetric 1,3‐Dipolar Cycloadditions of 2‐Diazocyclohexane‐1,3‐diones and Alkyl Diazopyruvates
Authors: Müller Paul , Chappellet Sabrina 
Published: May 2005

AbstractThe 1,3‐dipolar cycloaddition reactions of 2‐diazocyclohexane‐1,3‐dione (7a; Table 1) and of alkyl diazopyruvates (11a–e; Table 3) to 2,3‐dihydrofuran and other enol ethers have been investigated in the presence of chiral transition metal catalysts. With RhII catalysts, the cycloadditions were not enantioselective, but those catalyzed by [RuIICl2(1a)] and [RuIICl2(1b)] proceeded with enantioselectivities of up to 58% and 74% ee, respectively, when diazopyruvates 11 were used as substrates. The phenyliodonium ylide 7c yielded the adduct 8a in lower yield and poorer selectivity than the corresponding diazo precursor 7a (Table 2) upon decomposition with [Ru(pybox)] catalysts. This suggests that ylide decomposition by RuII catalysts, contrary to that of the corresponding diazo precursors, does not lead to Ru‐carbene complexes as reactive intermediates. Our method represents the first reproducible, enantioselective 1,3‐cycloaddition of these types of substrates.
Sarcophytonolides A–D, Four New Cembranolides from the Hainan Soft Coral Sarcophyton sp.
Authors: Jia Rui , Guo Yue‐Wei , Mollo Ernesto , Cimino Guido 
Published: May 2005

AbstractFour new cembranolide diterpenes, sarcophytonolides A–D (1–4), were isolated from a Hainan soft coral Sarcophyton sp. Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison with related model compounds.
Use of Dibutyl[14C]formamide as a Formylating Reagent in the Vilsmeier–Haack Reaction and Synthesis of a 14C‐Labeled Novel Phosphodiesterase‐4 (PDE‐4) Inhibitor
Authors: Ho Jonathan Z. , Elmore Charles S. , Wallace Michael A. , Yao Dan , Braun Matthew P. , Dean Dennis C. , Melillo David G. , Chen Cheng‐yi 
Published: May 2005

AbstractA simple, high‐yielding synthesis of dibutyl[14C]formamide ([14C]DBF; 1) from 14CO2 was developed (Scheme 1): reaction of LiBEt3H and 14CO2 followed by aqueous workup gave H14CO2H in high yield. Conversion of the [14C]formic acid to 1 was effected by a standard carbodiimide coupling procedure. The utility of 1 as an alternative to dimethyl[14C]formamide ([14C]DMF) in alkylation reactions and in the [14C]Vilsmeier–Haack reaction was demonstrated for several substrates (Table 2). A 14C‐labeled phosphodiesterase‐4 (PDE‐4) inhibitor, [14C]‐2, was synthesized by application of this technology (Scheme 2).
New Iridoid Triesters from Valeriana jatamansi
Authors: Yu Lili , Huang Rong , Han Changri , Lv Yuping , Zhao Yong , Chen Yegao 
Published: May 2005

AbstractTwo new iridoid triesters, valeriotriates A (1) and B (2), were isolated from the roots of Valeriana jatamansi Jones. Their structures were elucidated by HR‐ESI‐MS and 1D‐ and 2D‐NMR spectroscopy.
Reductive Elimination of Phenylsulfonyl Groups in the 3‐Position of Benzo[a]heptalene‐2,4‐diols
Authors: eldin Abdel Fattah Mohy , El Rayes Samir , Soliman El Sayed Ahmed , Linden Anthony , Abou‐Hadeed Khaled , Hansen Hans‐Jürgen 
Published: May 2005

Abstract3‐(Phenylsulfonyl)benzo[a]heptalene‐2,4‐diols 1 can be desulfonylated with an excess of LiAlH4/MeLi⋅LiBr in boiling THF in good yields (Scheme 6). When the reaction is run with LiAlH4/MeLi, mainly the 3,3′‐disulfides 6 of the corresponding 2,4‐dihydroxybenzo[a]heptalene‐3‐thiols are formed after workup (Scheme 7). However, the best yields of desulfonylated products are obtained when the 2,4‐dimethoxy‐substituted benzo[a]heptalenes 2 are reduced with an excess of LiAlH4/TiCl4 at −78→20° in THF (Scheme 10). Attempts to substitute the PhSO2 group of 2 with freshly prepared MeONa in boiling THF led to a highly selective ether cleavage of the 4‐MeO group, rather than to desulfonylation (Scheme 13).
Lupane Pentacyclic Triterpenes Isolated from Stems and Branches of Maytenus imbricata (Celastraceae)
Authors: Ribeiro de Souza e Silva Silvia , de Fátima Silva Gracia Divina , de Almeida Barbosa Luca Cláudio , Duarte Lucienir Pains , Filho Sidney Augusto Vieira 
Published: May 2005

AbstractFour lupane pentacyclic triterpenes were isolated from the hexane extract of stems and branches of Maytenus imbricata Mart. ex Reissek: 3‐oxolup‐20(30)‐en‐29‐al (1), 30‐hydroxylup‐20(29)‐en‐3‐one (2), (11α)‐11‐hydroxylup‐20(29)‐en‐3‐one (3), and (3β)‐lup‐20(30)‐ene‐3,29‐diol (4). The structural identification of 1–4 was achieved by 1H‐ and 13C‐NMR techniques, including 2D experiments (HSQC, HMBC, and NOESY).
A Macrobicyclic Calix[6]arene Phosphocine: Conformational Studies Involving High‐Resolution NMR Analysis and Molecular Modeling
Authors: Regnouf‐de‐Vains Jean‐Bernard , Cartier Alain , Fenet Bernard , Pellet‐Rostaing Stéphane 
Published: May 2005

AbstractThe solution structure of the phosphorylated hexa(tert‐butyl)calix[6]arene 1a was elucidated through a series of high‐resolution, one‐ and two‐dimensional 1H‐ and 13C‐NMR experiments, in combination with 31P‐NMR measurements. The NMR results were cross‐checked and refined with partial structural information obtained from a poorly resolved X‐ray crystal‐structure analysis. The latter, that could not be upgraded due to the low quality of the crystals and due to strong thermal motions, confirmed that 1a was a racemate in which two adjacent phenol units are bridged by a mono‐ethyl phosphate moiety, generating a macrocyclic dibenzo[1,3,2]dioxaphosphocine substructure, while the four residual aromatic rings bear regular diethyl phosphate arms. One of these rings is inverted, generating the main asymmetry in the molecule, which gives rise to the racemic nature of the macrobicycle. The two enantiomers, however, do not interconvert on the NMR time scale in solution and resemble the solid‐state structure, as expected from the steric hindrance due to the pendant phosphoesters and the high intramolecular tension due to the presence of the phosphocine substructure. The most‐probable conformation of 1a in solution was determined, starting from the NMR and X‐ray data, by means of semi‐empirical PM3 calculations with the GEOMOS program, including an unprecedented large number of 232 atoms.
Six New Triterpene Saponins with a 21,23‐Lactone Skeleton from Gynostemma pentaphyllum
Authors: Yin Feng , Hu Li‐Hong 
Published: May 2005

AbstractThe six new triterpene saponins 1–6 with a 21,23‐lactone skeleton were isolated from the MeOH extract of the aerial parts of Gynostemma pentaphyllum. Their structures were elucidated by 1D‐ and 2D‐NMR‐spectra interpretation as well as by chemical degradation.
Syntheses and Crystal Structures of Four New Ammoniates with Heptaarsenide (As$\rm{_{7}^{3-}}$) Anions
Authors: Hanauer Tobias , Grothe Michael , Reil Markus , Korber Nikolaus 
Published: May 2005

AbstractThe syntheses and X‐ray single‐crystal low‐temperature structures of the four new ammoniates [Li(NH3)4]3As7⋅NH3 (1), [Rb(18‐crown‐6)]3As7⋅8 NH3 (2), Cs3As7⋅6 NH3 (3), and (Ph4P)2CsAs7⋅5 NH3 (4) are reported. The compounds were obtained by either direct reduction of As with Li/Cs in liquid NH3, solvation of Cs4As6/Rb4As6 in liquid NH3, or by extraction of solid Cs3As7. While compound 1 contains isolated As$\rm{_{7}^{3-}}$ polyanions, AsM contacts (M=Na−Cs) lead to neutral [Rb(18‐crown‐6)]3As7 units in 2, a three‐dimensional, extended network in 3, and one‐dimensional, infinite $\rm{_{\infty }^{1}}$[CsAs7]2− chains in 4, respectively.
Three New Highly Oxygenated Diterpenoids from Excoecaria cochinchinensis Lour.
Authors: Yang Jing‐Hua , Luo Shi‐De , Zhao Jing‐Feng , Wang Yun‐song , Huang Rong , Zhang Hong‐Bin , Li Liang 
Published: May 2005

AbstractChemical examination of the AcOEt extract of the leaves and twigs of Excoecaria cochinchinensis Lour. collected from Xishuangbanna resulted in the isolation of the three new highly oxygenated diterpenoids 1–3. The structures of the new diterpenoids were elucidated by a study of their physical and spectra data as (2β,3β,5α,6α)‐2,3‐bis(acetyloxy)‐8,13‐epoxy‐6,9‐dihydroxylabd‐14‐en‐11‐one (=excolabdone A; 1), (1α,5α,6β,7β)‐1,6‐bis(acetyloxy)‐8,13‐epoxy‐7,9‐dihydroxylabd‐14‐en‐11‐one (=excolabdone B; 2), and (1α,5α,6β,7β)‐6‐(acetyloxy)‐8,13‐epoxy‐1,7,9‐trihydroxylabd‐14‐en‐11‐one (=excolabdone C; 3).
A Novel Intramolecular Photocyclization of N‐(2‐Bromoalkanoyl) Derivatives of 2‐Acylanilines via 1,8‐Hydrogen Abstraction
Authors: Nishio Takehiko , Koyama Hiroyuki , Sasaki Daigo , Sakamoto Masami 
Published: May 2005

AbstractThe photochemical reactions of different N‐(2‐acylphenyl)‐2‐bromo‐2‐methylpropanamides have been investigated. Irradiation of the N‐unsubstituted anilides 1a–1c gave the corresponding dehydrobromination, cyclization, and bromo‐migration products 2, 3, and 4, respectively (Table 1). Irradiation of the N‐alkyl anilides 1e–1g afforded the corresponding deacylation and cyclization products 5 and 6, respectively, whereas irradiation of the N‐alkyl anilides 1i–1k, carrying 2‐benzoyl groups on the aromatic rings, afforded the unexpected tricyclic lactams 7 (besides 2, 5, and 6). The formation of the cyclization products 6 could be rationalized in terms of an electrocyclic ring closure of the 6π‐electron‐conjugated enamides 2 produced by dehydrobromination of 1, followed by thermal 1,5‐acyl migration (Path B in the Scheme). The formation of the bridged lactams 7 probably follows a mechanism involving the 1,7‐diradical 8 generated by ζ‐H‐abstraction (1,8‐H transfer) by an excited acyl O‐atom (Path A).
Forbidden subgraphs and bounds on the size of a maximum matching
Authors: Plummer Michael D. , Saito Akira 
Published: May 2005

AbstractLet K1,n denote the star on n + 1 vertices; that is, K1,n is the complete bipartite graph having one vertex in the first vertex class of its bipartition and n in the second. The special graph K1,3, called the claw, has received much attention in the literature. In particular, a graph G is said to be claw‐free if G possesses no K1,3 as an induced subgraph. A well‐known theorem of Sumner and, independently, Las Vergnas says that every connected even claw‐free graph contains a perfect matching. (Later, Jünger, Pulleyblank, and Reinelt proved that if G is connected, claw‐free, and odd, then G must contain a near‐perfect matching.) More generally, Sumner proved that if G is K1,n‐free, (n − 1)‐connected, and even, then G must contain a perfect matching. In this paper, we extend these results in several ways. First, we show that if G is a k‐connected K1,n‐free graph on p vertices, then def(G) is bounded above by a certain function of k,n, and p, where def(G) is the deficiency of G. (The deficiency of a graph measures how far a maximum matching is from being perfect; that is, def (G) = p − 2ν(G), where ν(G) is the size of any maximum matching in G.) We then provide examples to show that this upper bound is sharp for each value of k and n. We then prove a result that is a type of converse to the above theorem in the following sense. Suppose that H is a connected graph and suppose that there exist constants α and β, 0 ≤ α < 1, such that every k‐connected H‐free graph G of sufficiently large order satisfies (G) ≤ α|V(G)| + β. Then the excluded subgraph H must be a K1,n, where n is bounded above by a certain function of α and k. © 2005 Wiley Periodicals, Inc. J Graph Theory
Developmental changes in Trichoderma viride enzymes abundant in conidia and the light‐induced conidiation signalling pathway
Authors: Pokorný Richard , Vargovič Peter , Hölker Udo , Janssen Martina , Bend Jutta , Hudecová Daniela , Varečka L'udovít 
Published: May 2005

AbstractThe expression of glutamic acid decarboxylase gene and the laccase activity were measured during the development of surface‐cultivated Trichoderma viride mycelia in order to examine their up‐regulation by light. The results show that the changes in activity of GAD induced by light observed previously are caused by transcriptional regulation of gad gene expression in both submerged mycelia and aerial mycelia after photoinduction. The expression of tga gene encoding a T. viride Gα protein was found not to be up‐regulated by light and was also present in the non‐conidiating mutant of T. viride suggesting that this protein is not involved in the regulation of conidiation in this fungus, or that it plays a role is in later stages of conidia development. The activity of laccase was also not light‐inducible and may be related to the maturation of conidia. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of an arbuscular mycorrhizal fungus, Glomus mosseae, and a rock‐phosphate‐solubilizing fungus, Penicillium thomii, on Mentha piperita growth in a soilless medium
Authors: Cabello Marta , Irrazabal Gabriela , Bucsinszky Ana Maria , Saparrat Mario , Schalamuk Santiago 
Published: May 2005

AbstractRock phosphate effect on English mint (Mentha piperita L.) grown on steamed perlite:vermiculite (1:1, v:v) substrate, with and without rock phosphate, was evaluated in greenhouse experiments. Five treatments were carried out by inoculation with an arbuscular mycorrhizal fungus Glomus mosseae and a phosphorus solubilizing microorganism Penicillium thomii. Plant aerial biomass, phosphorus concentration in plant tissue, and P available in the substrate, were evaluated upon two harvests. After the first harvest, plant aerial biomass did not show significant differences between treatments using rock phosphate as fertilizer, although P content in plants inoculated with P. thomii was higher. The second harvest revealed a higher biomass and plant tissue P content in treatments inoculated with G. mosseae. P. thomii increased P available in the substrate, whereas in the absence of G. mosseae, it did not enhance plant tissue P content. Mycorrhizal colonization was not affected by P. thomii. Microbial inoculation effect on English mint growth was also evaluated. The microbial effect was positive in all treatments when compared with the control without rock phosphate. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Production of 2‐methylisoborneol by Streptomyces violaceusniger and its transformation by selected species of Pseudomonas
Authors: Saadoun Ismail 
Published: May 2005

AbstractThe effect of glucose, glycerol and yeast‐extract (YE) on 2‐methylisoborneol (MIB) production by Streptomyces violaceusniger (C4–S strain) was determined. Glycerol as a sole carbon source promoted MIB production was maximum concentration (40.65 µg/l) after 10 days incubation, while glucose favored biomass production. Increasing YE concentration from 0.1 to 1% (W/V) repressed MIB production with 62 and 83% reduction after 10 and 14 days, respectively. Transformation of this odorous compound was investigated using seven different Pseudomonas species. Action of the different Pseudomonas spp. on the C4–S extract was followed at 1 hour, 2 hours, 6 hours and 12 hours. Pseudomonas spp. 1, 2, 3 and 5 indicated a positive reaction; however, Pseudomonas spp. 4, 6 and 7 showed no effect. These data suggest that 2‐methylisoborneol can be transformed by Pseudomonas spp. and the test adopted by this study can be applied for screening organisms for their ability to transform MIB. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hyperbranching induced by cold‐shock or snow‐flake mutation in Neurospora crassa is prevented by addition of exogenous calcium
Authors: Kawano Cristina Y. , Said Suraia 
Published: May 2005

AbstractHyphal tip growth is a highly polarized process of cell extension, which may be affected by chemical and physical stress. Neurospora crassa exposed to cold‐shock lost its polarized growth and dichotomous branches were detected. These effects were not observed in the presence of 500 mM Ca2+. We compared here the morphological pattern of a snow‐flake mutant (sn) and the wild‐type (wt) exposed to 4 °C. Hyphal morphology, nuclei, actin and microtubule distribution were analyzed. No effects on sn hyphal morphology were detected at 4 °C. Exogenous Ca2+ converted sn to an essentially wt appearance. The results presented here suggest that sn mutation and cold‐shock treatment have affected Ca2+ influx since addition of this cation to sn (30 °C) and to wt (4 °C) maintained polarized growth and normal nuclear and microtubules distribution. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)