Synthesis and gene transfer activities of novel serum compatible cholesterol-based gemini lipids possessing oxyethylene-type spacers

Four novel cholesterol-based gemini cationic lipids differing in the length of oxyethylene-type spacers [-CH2-(CH2-O-CH2)n-CH2-] between each ammonium headgroup have been synthesized. These formed stable suspensions in aqueous media. Cationic liposomes were prepared from each of these lipids individually and as mixtures of cationic lipid and DOPE. These were used as nonviral gene delivery agents. All the cholesterol-based gemini lipids induced better transfection activity than their monomeric counterpart. Inclusion of DOPE in co-liposomal formulation of the cationic gemini lipid potentiates their gene transfer activity significantly. A major characteristic feature of these oxyethylene spacer based cholesterol gemini lipids was that serum does not inhibit the transfection activity of these gemini lipids, whereas the transfection activity of their monomeric counterpart decreased drastically in the presence of serum. One of the cholesterol-based gemini lipids 2a possessing a -CH2-CH2-O-CH2-CH2- spacer showed the highest transfection activity.     

Effect of the hydrocarbon chain and polymethylene spacer lengths on gene transfection efficacies of gemini lipids based on aromatic backbone

Design, syntheses, and gene delivery efficacies of fifteen novel gemini (dimeric) and three monomeric cationic lipids anchored on an aromatic backbone have been described. Each new lipid has been used for liposome formation, and optimal formulations were used to determine the structure-activity correlation of the gene transfection efficacies of these lipids in HeLa and HT1080 cells. The results of the present investigation bring out the effect of hydrocarbon chain lengths and the length of the spacer between the headgroups on gene transfection efficiencies of the cationic gemini lipids based on aromatic backbone. The lipids bearing n-C 14H 29 hydrocarbon chain lengths have been found to be the best transfecting agents compared to their counterparts with n-C 16H 33 and n-C 12H 25 chains in HeLa cells. On the other hand, in HT1080 cells, the lipids based on n-C 12H 25 and n-C 14H 29 chains were found to be more potent transfecting agents than lipids possessing n-C 16H 33 chains. Transmission electron microscopy examination revealed the existence of spherical lipid-DNA complexes.     

Small molecule inhibitors of E. coli primase, a novel bacterial target

Bacterial primase is essential for DNA replication in Gram-positive and Gram-negative bacteria. It is also structurally distinct from eukaryotic primases, and therefore an attractive, but under-explored, target for therapeutic intervention. We applied virtual screening to discover primase inhibitors, and subsequently several commercially available analogs of these initial hits showed potent primase inhibition and in vitro antibacterial activity. This work provides a 3D pharmacophore for primase ligands, SAR trends, and leads that can be further optimized.     

The complete genome sequence of Bacillus thuringiensis Al Hakam

Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (E. Schnepf, N. Crickmore, J. Van Rie, D. Lereclus, J. Baum, J. Feitelson, D. R. Zeigler, and D. H. Dean, Microbiol. Mol. Biol. Rev. 62:775-806, 1998). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (L. Radnedge, P. Agron, K. Hill, P. Jackson, L. Ticknor, P. Keim, and G. Andersen, Appl. Environ. Microbiol. 69:2755-2764, 2003).     

Deletion of the developmentally essential gene ATR in adult mice leads to age-related phenotypes and stem cell loss

Developmental abnormalities, cancer, and premature aging each have been linked to defects in the DNA damage response (DDR). Mutations in the ATR checkpoint regulator cause developmental defects in mice (pregastrulation lethality) and humans (Seckel syndrome). Here we show that eliminating ATR in adult mice leads to defects in tissue homeostasis and the rapid appearance of age-related phenotypes, such as hair graying, alopecia, kyphosis, osteoporosis, thymic involution, fibrosis, and other abnormalities. Histological and genetic analyses indicate that ATR deletion causes acute cellular loss in tissues in which continuous cell proliferation is required for maintenance. Importantly, thymic involution, alopecia, and hair graying in ATR knockout mice were associated with dramatic reductions in tissue-specific stem and progenitor cells and exhaustion of tissue renewal and homeostatic capacity. In aggregate, these studies suggest that reduced regenerative capacity in adults via deletion of a developmentally essential DDR gene is sufficient to cause the premature appearance of age-related phenotypes.     

Field‐compatible protocol for detecting tetracyclines with bioluminescent bioreporters without pipetting steps

Whole‐cell bioreporters are living organisms and thus using them for detecting environmental contaminants would reflect biological effects of these pollutants. However, bioreporters are not widely used in field studies. Many of the bioreporter field protocols are suitable for liquid samples or include pipetting steps, which is a demanding task outside the laboratory. We present a bioreporter protocol without pipetting or sample type requirements. The protocol utilizes polyester swabs, commonly used in cleanroom technology. As an example contaminant, we used tetracycline and generated test samples with known concentrations up to the maximum tetracycline residue limit of milk set by the European Union (EU) regulation. The matrices of the test samples were Milli‐Q water, milk and soil. The swabs were first dipped in the bioreporter cell cultures and then to test samples and luminescence was measured after incubation. The standard deviation of measurements from ten replicate swabs was in the same range as commonly in pipetting protocols (4–19%). The test samples with lowest tetracycline concentration (5 ng mL^?1) were distinguished from the control samples (0 ng mL^?1 tetracycline). Our results show that swabs can be used together with luminescent whole cell bioreporters, making it possible to conduct the measurements in field conditions.     

Lactic acid and its separation and purification techniques: A review

Reviews in Environmental Science and Bio/Technology - In this current review article, a significant number of published articles were reviewed in order to provide comprehensive literature...     

Transient in utero disruption of Cystic Fibrosis Transmembrane Conductance Regulator causes phenotypic changes in Alveolar Type II cells in adult rats

Background  

Mechanicosensory mechanisms regulate cell differentiation during lung organogenesis. We have previously demonstrated that cystic fibrosis transmembrane conductance regulator (CFTR) was integral to stretch-induced growth and development and that transient expression of antisense-CFTR (ASCFTR) had negative effects on lung structure and function. In this study, we examined adult alveolar type II (ATII) cell phenotype after transient knock down of CFTR by adenovirus-directed in utero expression of ASCFTR in the fetal lung.