Structural basis of membrane bending by the N-BAR protein endophilin

Functioning as key players in cellular regulation of membrane curvature, BAR domain proteins bend bilayers and recruit interaction partners through poorly understood mechanisms. Using electron cryomicroscopy, we present reconstructions of full-length endophilin and its N-terminal N-BAR domain in their membrane-bound state. Endophilin lattices expose large areas of membrane surface and are held together by promiscuous interactions between endophilin's amphipathic N-terminal helices. Coarse-grained molecular dynamics simulations reveal that endophilin lattices are highly dynamic and that the?N-terminal helices are required for formation of a stable and regular scaffold. Furthermore, endophilin accommodates different curvatures through?a quantized addition or removal of endophilin dimers, which in some cases causes dimerization of endophilin's SH3 domains, suggesting that the spatial presentation of SH3 domains, rather than affinity, governs the recruitment of downstream interaction partners.     

Characterization of Staphylococcus aureus Strains Associated with Food Poisoning in Shenzhen, China

To characterize isolates of Staphylococcus aureus that were associated with staphylococcal food poisoning between 2006 and 2009 in Shenzhen, Southern China, a total of 52 Staphylococcus aureus isolates from 11 outbreaks were analyzed by using multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE). PCR analysis was used to analyze the staphylococcal enterotoxin (SE) genes sea to sei, and antimicrobial susceptibility testing was also performed. ST6 was the most dominant sequence type (ST), constituting 63.5% (34/52) of all of the isolates in 7 outbreaks. The next most common ST was ST943, which constituted 23.1% (12/52) of the isolates that were collected from 3 outbreaks. t701, t091, and t2360 were the most predominant spa types, constituting 67.3% (35/52) of the isolates that were collected from 11 outbreaks. Three PFGE types, (types A, B, and C) were the most frequently observed types, constituting 84.6% (44/52) of all of the isolates. The enterotoxin gene that we detected most frequently was sea (45/52; 86.5%). Four SE gene profiles were observed, including sea (n = 45), sec-seh (n = 3), seb (n = 2), and seg-sei (n = 2). With respect to antibiotic resistance, penicillin resistance was the most common (96.2%; 50/52), followed by resistance to tetracycline (28.8%; 15/52). Approximately 30.8% (16/52) of the isolates were resistant to at least two antibiotics, and 7.7% (4/52) of the isolates were resistant to three or more drugs. The two predominant S. aureus lineages, (i) PFGE types A and B with ST6 and (ii) PFGE type C with ST943, were identified in the outbreaks.     

Lagerstroemia menglaensis sp. nov. (Lythraceae) from Xishuangbanna,Yunnan Province,China

Lagerstroemia menglaensis C. H. Gu, M. C. Ji & D. D. Ma, a new species of Lythraceae from Xishuangbanna, Yunnan, China is described and illustrated. The morphological characteristics of the new species and two morphologically similar species (L. guilinensis and L. venusta) are compared, and a key to distinguish between them is provided.     

Pretreatment of Populus tomentosa with Trametes velutina supplemented with inorganic salts enhances enzymatic hydrolysis for ethanol production

Different nutrients were added into the solid fermentation of woody biomass, Populus tomentosa, to improve pretreatment by a white rot fungus, Trametes velutina. Fungal pretreatment supplemented with trace elements resulted in large amount of lignin loss but low degradation of carbohydrate. Only 12.6?% of Klason lignin was left in the residues pretreated by T. velutina for 8?weeks supplemented with 1?% trace elements (TE group). When fungal-pretreated residues were subjected to enzymatic hydrolysis for 96?h, a maximum reducing sugar yield of 44?% was obtained from the TE group at the 8th week, 2.3 times higher than that of untreated samples. In addition, the highest ethanol yield of 22?% was observed by the fermentation of 8-week pretreated residues from the basic medium plus trace element group, which was five times more than that of untreated samples.     

Synthesis and characterization of a novel potato starch derivative with cationic acetylcholine groups

A novel substance, cationic acetylcholine potato starch (CAPS), was developed for the first time. The synthesis process had three steps: first, carboxymethyl potato starch (CMPS) was synthesized under sodium hydroxide alkaline condition and in isopropyl alcohol organic media; second, bromocholine chloride (BCC) was synthesized with sulphuric acid as a catalytic agent; finally, CAPS was synthesized by the reaction of CMPS with BCC in N,N'-dimethylformamide (DMF). The degree of substitution (DS) of CAPS was determined by ammonia gas-sensing electrode and elemental analysis. CAPS was characterized by Fourier transformed infrared (FTIR) and near infrared (FTNIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC).     

Cloning, expression and characterization of meso-2,3-butanediol dehydrogenase from Klebsiella pneumoniae

The budC gene encoding the meso-2,3-BDH from Klebsiella pneumoniae XJ-Li was expressed in E. coli BL21 (DE3) pLys. Hypothetical amino acid sequence alignments revealed that the enzyme belongs to the short chain dehydrogenase/reductase family. After purification and refolding, the recombinant enzyme had activities of 218 U/mg for reduction of acetoin and 66 U/mg for oxidation of meso-2,3-butanediol. Highest activities were at pH 8.0 and 9.0 respectively. These are higher than other meso-2,3-butanediol dehydrogenases from K. pneumoniae. The low K (m) value (0.65 mM) for acetoin indicated that the enzyme can easily reduce acetoin to meso-2,3-butanediol. There were no significant activities towards 2R,3R-2,3-butanediol, 1,4-butanediol and 2S,3S-2,3-butanediol, suggesting that the enzyme has a high stereospecificity for the meso-dihydric alcohol.     

Interaction of 3'-azido-3'-deamino daunorubicin with DNA: multispectroscopic and molecular modeling

In this paper, 3'-azido-3'-deamino daunorubicin (ADNR) was synthesized and the interaction of ADNR and calf thymus DNA (ctDNA) was investigated for the first time by using multi-spectroscopic techniques and molecular modeling study in vitro under simulated physiological conditions. Hypochromicity of the absorption spectra of ADNR were observed in the presence of ctDNA, and the fluorescence of ADNR was strongly quenched through static mechanism with the addition of ctDNA. Moreover, the fluorescence polarization was increased when ctDNA was added. From the experimental results, conclusion can be drawn that the binding mode of ADNR with ctDNA was an intercalative binding, and the calculated thermodynamic parameters suggested that the binding of ADNR to ctDNA was driven mainly by hydrogen bonding force. Furthermore, the results obtained from computational modeling further proved the experimental results obtained from spectroscopic investigations.     

Draft Genome Sequence of Yersinia pestis Strain 2501, an Isolate from the Great Gerbil Plague Focus in Xinjiang, China

We deciphered the genome of Yersinia pestis strain 2501, isolated from the Junggar Basin, a newly discovered great gerbil plague focus in Xinjiang, China. The total length of assembly was 4,597,322 bp, and 4,265 coding sequences were predicted within the genome. It is the first Y. pestis genome from this plague focus.     

Draft genome sequences of two Legionella dumoffii strains, TEX-KL and NY-23

Legionella (Fluoribacter) dumoffii is one of the agents causing Legionnaires' disease. Here, we used Illumina second-generation sequencing technology to decipher for the first time the whole-genome sequences of two strains of this species, TEX-KL and NY-23. The assembly results for both strains consist of one chromosome and two plasmids.     

Complete Genome Sequence of Brucella melitensis Biovar 3 Strain NI,Isolated from an Aborted Bovine Fetus

From an aborted bovine fetus in China, a bacterial strain named NI was isolated and identified as Brucella melitensis by a PCR assay. Strain NI was further characterized as B. melitensis biovar 3 using biochemical assays. Here we report the complete genome sequence of strain NI.