Cyclodextrin-modified polyethylenimine polymers for gene delivery

Linear and branched poly(ethylenimines), lPEI and bPEI, respectively, grafted with beta-cyclodextrin are prepared to give CD-lPEI and CD-bPEI, respectively, and are investigated as in vitro and in vivo nonviral gene delivery agents. The in vitro toxicity and transfection efficiency are sensitive to the level of cyclodextrin grafting. The cyclodextrin-containing polycations, when combined with adamantane-poly(ethylene glycol) (AD-PEG) conjugates, form particles that are stable at physiological salt concentrations. PEGylated CD-lPEI-based particles give in vitro gene expression equal to or greater than lPEI as measured by the percentage of EGFP expressing cells. Tail vein injections into mice of 120 microg of plasmid DNA formulated with CD-lPEI and AD-PEG do not reveal observable toxicities, and both nucleic acid accumulation and expression are observed in liver.     

High-throughput Protein Production for X-ray Crystallography and Use of Size Exclusion Chromatography to Validate or Refute Computational Biological Unit Predictions

The production of large numbers of highly purified proteins for X-ray crystallography is a significant bottleneck in structural genomics. At the Joint Center for Structural Genomics (JCSG; http://www.jcsg.org), specific automated protein expression, purification, and analytical methods are being utilized to study the proteome of Thermotoga maritima. Anion exchange and size exclusion chromatography (SEC), intended for the production of highly purified proteins, have been automated and the procedures are described here in detail. Analytical SEC has been included as a standard quality control test. A biological unit (BU) is the macromolecule that has been proven or is presumed to be functional. Correct assignment of BUs from protein structures can be difficult. BU predictions obtained via the Protein Quaternary Structure file server (PQS; http://pqs.ebi.ac.uk/) were compared to SEC data for 16 representative T. maritima proteins whose structures were solved at the JCSG, revealing an inconsistency in five cases. Herein, we report that SEC can be used to validate or disprove PQS-derived oligomeric models. A substantial amount of associated SEC and structural data should enable us to use certain PQS parameters to gauge the accuracy of these computational models and to generally improve their predictions.     

Constituents of Acacia cedilloi and Acacia gaumeri. Revised structure and complete NMR assignments of resinone

The rare lupene derivative named resinone has only been isolated before from Fluorensia resinosa. We now report the isolation of this compound from the bark of the new recently described Acacia cedilloi (Fabaceae), and the revision of its structure to 16beta-hydroxylup-20(29)-en-3-one, based on NMR and MS spectral data. The detailed 1H and 13C NMR assignments of resinone and its acetate achieved by 1D and 2D NMR experiments (including DEPT, COSY, HMQC and HMBC) are reported. In addition, the study of A. cedilloi and A. gaumeri afforded the known related lupenes lupeol and lupenone, the acyclic squalene, the sterols beta-sitosterol, stigmasta-7,22-dien-3beta-ol (spinasterol) and stigmasta-5,22,25-trien-3beta-ol (22-dehydroclerosterol) as well as alpha-tocopherol and beta-carotene.     

Prenylflavans from Tephrosia watsoniana

The aerial parts of tephrosia watsoniana afforded five new flavonoids named tephrowatsin A, B, C, D and E. Their structures and stereochemistries were established by spectroscopic methods and chemical transformations.     

Tetraludin A,B and C,three new melampolides from Tetragonotheca ludoviciana

The investigation of the roots of the four Tetragonotheca species, T. ludoviciana, T. repanda, T. texana and T. helianthoides, resulted in the isolation of the known heptadeca-2-(Z)-8,10-(E)-16-tetraene-4,6-diin-1-ol and its aldehyde derivative from all four species. Aerial parts of T. ludoviciana also contained the acetate of the latter compound as a minor constituent and provided three new melampolide-type sesquiterpene lactones, tetraludin A, B and C.     

Enhancing the biomethane potential of liquid dairy cow manure by addition of solid manure fractions

Objectives

To assess the effect of adding solid manure fractions on the biomethane potential (BMP) of liquid dairy cow manure and on the biokinetic parameters of the process.

Results

The methanogenic potential of liquid dairy cow manure was strongly effected by adding a solid manure fraction. The 90/10 % (w/w) liquid/solid manure fraction mixture was the best substrate for CH₄ production. This substrate mixture improved by 50 % the final CH₄ production per g substrate and decreased the lag time by 220 % relative to the reference BMP test without the addition. Moreover, the addition of 20 % solid manure fraction adversely affected both the final CH₄ production and the maximum methane production rate, while increased the lag time by 400 % compared to the reference BMP test without addition.

Conclusions

Liquid dairy cow manure should be supplemented with no more than 10 % of solid manure fraction in order to improve the biomethane potential of this important agro-industrial residue.

     

Zoapatanolide A and B,two new heliangolides from Montanoa tomentosa

The re-investigation of Montanoa tomentosa afforded, in addition to known diterpenoids of the kaurene class, two new sesquiterpene lactones, zoapatanolide A and B, of the heliangolide type.