Organolanthanide constrained geometry complexes modified for catalysis: synthesis, structure, and aminoalkene hydroamination properties of a pyrrolidine-substituted constrained geometry organolutetium complex

The reaction of the organolutetium complex (CGC′)LuCl₃Li₂(THF), (1; CGC′ = [Me₂Si(3-pyrrolidinyl-1-η⁵-indenyl)(^tBuN)]²⁻) with NaN(TMS)₂ provides a straightforward route to the halide-free organolutetium amido complex, (CGC′)LuN(TMS)₂(THF) (2). These new complexes were characterized by standard analytical methodology. The monomeric complex 2 crystallizes in the monoclinic space group P2₁/c with four molecules in a cell of dimensions a = 11.1566(6) Å, b = 14.9805(8) Å, c = 22.18007(12) Å, and β = 90.0620(10)°. Complex 2 is an active precatalyst for the intramolecular hydroamination/cyclization of representative aminoalkenes with turnover frequencies as high as 205 h⁻¹ at room temperature.     

Small-sample inference for the comparison of means of log-normal distributions

We propose a likelihood-based test for comparing the means of two or more log-normal distributions, with possibly unequal variances. A modification to the likelihood ratio test is needed when sample sizes are small. The performance of the proposed procedures is compared with the F-ratio test using Monte Carlo simulations.     

Synthesis, crystal structures and, antibacterial and antiproliferative activities in vitro of palladium(II) complexes of triphenylphosphine and thioamides

Palladium(II) complexes with triphenylphosphine (PPh₃) and thioamides of the general formulae, [Pd(L)₂(PPh₃)₂]Cl₂ and [Pd(L)₂(PPh₃)₂] have been prepared and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ³¹P) methods, and two of them (trans-[Pd(PPh₃)₂(Dmtu)₂]Cl₂·(H₂O)(CH₃OH)_0.5 (1) and trans-[Pd(PPh₃)₂(Mpy)₂] (2)) by X-ray crystallography; where L = thiourea (Tu), methylthiourea (Metu), N,N′-dimethylthiourea (Dmtu), tetramethylthiourea (Tmtu), 2-mercaptopyridine (Mpy), 2-mercaptopyrimidine (Mpm) and thionicotinamide (Tna). The spectral data of the complexes are consistent with the sulfur coordination of thioamides to palladium(II). The crystal structures of the complexes show that (1) has ionic character consisting of [Pd(PPh₃)₂(Dmtu)₂]⁺² cations and uncoordinated Cl⁻ ions, while (2) is a neutral complex with Mpy behaving as anionic thiolate ligand. The coordination environment around palladium in (2) is nearly regular square-planar, while in (1) the trans angles show significant distortions from 180°. The complexes were screened for antibacterial effects, brine shrimps lethality bioassay and antitumor activity. These complexes showed significant activities in most of the cases against the tested bacteria as compared to that of a standard drug. Their antitumor activity against prostate cancer cells (PC3) is comparable with doxorubicin, together with no cytotoxic effects in brine shrimps lethality bioassay study.     

Deciphering synonymous codons in the three domains of life: Co-evolution with specific tRNA modification enzymes

The strategies organisms use to decode synonymous codons in cytosolic protein synthesis are not uniform. The complete isoacceptor tRNA repertoire and the type of modified nucleoside found at the wobble position 34 of their anticodons were analyzed in all kingdoms of life. This led to the identification of four main decoding strategies that are diversely used in Bacteria, Archaea and Eukarya. Many of the modern tRNA modification enzymes acting at position 34 of tRNAs are present only in specific domains and obviously have arisen late during evolution. In an evolutionary fine-tuning process, these enzymes must have played an essential role in the progressive introduction of new amino acids, and in the refinement and standardization of the canonical nuclear genetic code observed in all extant organisms (functional convergent evolutionary hypothesis).     

Improvement in fermentation characteristics of degermed ground corn by lipid supplementation

With rapid growth of fuel ethanol industry, and concomitant increase in distillers dried grains with solubles (DDGS), new corn fractionation technologies that reduce DDGS volume and produce higher value coproducts in dry grind ethanol process have been developed. One of the technologies, a dry degerm, defiber (3D) process (similar to conventional corn dry milling) was used to separate germ and pericarp fiber prior to the endosperm fraction fermentation. Recovery of germ and pericarp fiber in the 3D process results in removal of lipids from the fermentation medium. Biosynthesis of lipids, which is important for cell growth and viability, cannot proceed in strictly anaerobic fermentations. The effects of ten different lipid supplements on improving fermentation rates and ethanol yields were studied and compared to the conventional dry grind process. Endosperm fraction (from the 3D process) was mixed with water and liquefied by enzymatic hydrolysis and was fermented using simultaneous saccharification and fermentation. The highest ethanol concentration (13.7% v/v) was achieved with conventional dry grind process. Control treatment (endosperm fraction from 3D process without lipid supplementation) produced the lowest ethanol concentration (11.2% v/v). Three lipid treatments (fatty acid ester, alkylphenol, and ethoxylated sorbitan ester 1836) were most effective in improving final ethanol concentrations. Fatty acid ester treatment produced the highest final ethanol concentration (12.3% v/v) among all lipid supplementation treatments. Mean final ethanol concentrations of alkylphenol and ethoxylated sorbitan ester 1836 supplemented samples were 12.3 and 12.0% v/v, respectively.Mention of brand or firm names does not constitute an endorsement by University of Illinois or USDA above others of similar nature not mentioned     

Bridelionosides A-F: Megastigmane glucosides from Bridelia glauca f. balansae

The chemical investigation of leaves of Bridelia glauca f. balansae afforded six megastigmane glucosides, named bridelionosides A-F, along with seven known megastigmane glucosides. Their structures were determined by a combination of spectroscopic analyses and by application of the modified Mosher's method.     

Photosensitization of skin fibroblasts and HeLa cells by three chlorin derivatives: Role of chemical structure and delivery vehicle

The chemical nature of the sensitizer and its selective uptake by malignant cells are decisive to choose an appropriate biocompatible carrier, able to preserve the photosensitizing characteristics of the dye. In this paper we demonstrate the photodynamic properties of three chlorins, derived from chlorophyll a, and the usefulness of liposomal carriers to design pharmaceutical formulations. The chlorins have been quantitatively incorporated into stable liposomes obtained from a mixture of l-α-palmitoyloleoylphosphatidylcholine and l-α-dioleoylphosphatidylserine in a 13.5:1.5 molar ratio (POPC/OOPS-liposomes). The chlorin uptake by skin fibroblasts increases steadily, reaching in all cases a plateau level dependent on both the chlorin structure and the vehicle employed. The photophysical properties of the three chlorins in THF are nearly identical and fulfill the requirements for a PDT photosensitizer. Incorporation of chlorins into liposomes induces important changes in their photophysics, but does not impair their cellular uptake or their cell photosensitization ability. In fact we observe in the cells the same photophysical behavior as in THF solution. Specifically, we demonstrate, by recording the near-IR phosphorescence of ¹O₂, that the chlorins are able to photosensitize the production of ¹O₂ in the cell membrane. The cell-photosensitization efficiency depended on the chlorin and cell line nature, the carrier, and the length of pre-incubation and post-irradiation periods. The high photodynamic activity of chlorin-loaded liposomes and the possibility to design liposomal carriers to achieve a specific target site favors this approach to obtain an eventual pharmaceutical formulation.     

Detecting un-authorized genetically modified organisms (GMOs) and derived materials

Genetically modified plants, in the following referred to as genetically modified organisms or GMOs, have been commercially grown for almost two decades. In 2010 approximately 10% of the total global crop acreage was planted with GMOs (James, 2011). More than 30 countries have been growing commercial GMOs, and many more have performed field trials. Although the majority of commercial GMOs both in terms of acreage and specific events belong to the four species: soybean, maize, cotton and rapeseed, there are another 20 + species where GMOs are commercialized or in the pipeline for commercialization. The number of GMOs cultivated in field trials or for commercial production has constantly increased during this time period. So have the number of species, the number of countries involved, the diversity of novel (added) genetic elements and the global trade. All of these factors contribute to the increasing complexity of detecting and correctly identifying GMO derived material. Many jurisdictions, including the European Union (EU), legally distinguish between authorized (and therefore legal) and un-authorized (and therefore illegal) GMOs. Information about the developments, field trials, authorizations, cultivation, trade and observations made in the official GMO control laboratories in different countries around the world is often limited, despite several attempts such as the OECD BioTrack for voluntary dissemination of data. This lack of information inevitably makes it challenging to detect and identify GMOs, especially the un-authorized GMOs. The present paper reviews the state of the art technologies and approaches in light of coverage, practicability, sensitivity and limitations. Emphasis is put on exemplifying practical detection of un-authorized GMOs. Although this paper has a European (EU) bias when examples are given, the contents have global relevance.     

Intracellular expression and purification of the Canstatin-N protein in Pichia pastoris

Canstatin-N DNA fragment amplified from human genome was inserted into the MCS of pGAP9K*, an intracellular expression vector of Pichia pastoris, to generate pGAP9K*-can-N which was then transformed into P. pastoris GS115 by electroporation. A transformant was chosen as an engineering strain from the plate containing G418 (700 μg/ml). D-sorbitol was selected as the only carbon source. The fermentation was carried out in a 50 L bioreactor at a 20 L working volume. After 48 h fermentation with continuous feeding of 25% (w/v) D-sorbitol and 0.8% PTM4, the cell grew to A(600)=178 and intracellularly expressed Canstatin-N reached 780 mg/L. Snail enzyme was combined with water to crack P. pastoris and to release intracellular proteins. The purified recombinant Canstatin-N inhibited CAM angiogenesis and induced significant apoptosis of the human umbilical vein endothelial cell (EVC340).