Interrelations between the parasitophorous vacuole of Toxoplasma gondii and host cell organelles.

Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection by T. gondii tachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.     

A novel reaction of 6-amino-uracils and isatins

A simple and novel cyclo-condensation reaction of 6-amino-uracils and isatins for the synthesis of spiro[pyrimido[4,5-b]quinoline-5,5′-pyrrolo[2,3-d]pyrimidine] derivatives is reported.     

Synthesis of novel oxindolylpyrrolo[2,3-d]pyrimidines via a three-component sequential tandem reaction

A novel one-pot three-component reaction of 6-amino-uracil, isatin, and acetophenone was accomplished through a programmed pH variation for the synthesis of 5-(2-oxoindolin-3-yl)-1H-pyrrolo[2,3-d]pyrimidine-2,4(3H,7H)-dione derivatives. The reaction was conducted in a sequential tandem manner to give the oxindole substituted pyrrolo[2,3-d]pyrimidine products in good to excellent yields. Despite of timing all the processes were carried out in one pot. Most of these novel compounds show narrow to good spectrum of antimicrobial activities in vitro.     

Quantum gravity and Schrödinger equations on orbifolds

The importance of conical singularities in the configuration space of gravitation theory is pointed out. Consideration is given to a possible inequivalence of intrinsic and extrinsic quantization and to the behavour of the wave functional in the presence of such singularities.     

An enamine controlling group for rhodium-catalyzed intermolecular hydroacylation

An enamine-controlled hydroacylation of alkynes using a rhodium(I)/dppe catalyst system is described. The reaction is highly selective, forming the linear enaminone products as single regioisomers in all examples. In situ hydrolysis of the enamine functionality generated α-substituted 1,3-diketone products, and Lewis-acid mediated intramolecular conjugate addition of the hydroacylation products gave substituted hexahydroquinolones.     

Synthesis of 4-substituted pyrano[4,3-b]pyran-2,5-diones in an ionic liquid

The mildly basic ionic liquid N,N,N,N-tetramethylguanidinium triflate (TMGTf) was found to be a very effective solvent for the reaction between 4-hydroxy-6-methyl-2H-pyran-2-one, Meldrum's acid, and aldehydes to afford some novel pyrano[4,3-b]pyran-2,5-diones in high yields at room temperature. The stages, through which these reactions might proceed, depend largely on the nature of the aldehyde substrates. The reaction of aliphatic aldehydes has given access to some novel carboxylated products.     

An Efficient and Rapid Approach to Quinolines via Friedländer Synthesis Catalyzed by Silica Gel Supported Sodium Hydrogen Sulfate Under Solvent-Free Conditions

Summary. A simple and efficient method for the synthesis of quinolines and polycyclic quinolines using silica gel supported sodium hydrogen sulfate as reusable eco-friendly catalyst via Friedl?nder annulation under solvent-free conditions is described.     

Clean synthesis and antibacterial activities of spiro[pyrimido[4,5-b]quinoline-5,5'-pyrrolo[2,3-d]pyrimidine]-pentaones

A simple, clean and efficient method for the synthesis of spiro[pyrimido[4,5-b]quinoline-5,5'-pyrrolo[2,3-d]pyrimidine]-pentaone derivatives by condensation reaction of 6-amino-uracils and isatins in aqueous media is reported. These products were evaluated in vitro for their antibacterial activities.