4-Thiaproline reduces heart lipid peroxidation and collagen accumulation in the diabetic db/db mouse

Summary Collagen accumulation is a main pathological feature of diabetic cardiomyopathy. The underlying mechanisms seem to be increased cross linking by reactive carbonyles. The purpose of the study was to decrease the collagen content of total ventricular tissue by the oral administration of thiaproline, which could reduce collagen due to its functions as a proline analogue, blocking collagen production and as a free oxygen radical scavenger, blocking reactive carbonyles and oxygen species and subsequently collagen cross linking.Thiaproline was administered to genetically diabetic db/db mice and compared to untreated animals. Total ventricular collagen as expressed by hydroxyproline was significantly lower in the treated group (means 0.23 micromoles/10 tissue in the treated vs 0.35 micromoles/100 mg tissue in the untreated group, p < 0.001). Significantly more collagen could be eluted in the treated group (p < 0.001) and carboxymethyllysine was significantly reduced in the treated group (p < 0.001). Di-tyrosine and glycemic control did not differ between the groups. Glutathione was significantly increased in the TP treated experimental group (p < 0.001) and lipid peroxidation products were significantly decreased (means 0.221 absorbance in the treated group versus 0.321 absorbance in the untreated diabetic group) correlating with total ventricular collagen content (r = 0.87, p < 0.01).We conclude that thiaproline reduced total ventricular collagen content by inhibiting collagen cross linking as reflected by increased solubility of collagen and expressed by higher elution quantity of collagen. Thiaproline, and/or its metabolites induced increase of heart glutathione which may well have been scavenging reactive carbonyles derived from lipid peroxidation and advanced stage nonenzymatic glycosylation as shown by decreased total ventricular carboxy-methyllysine and lipid peroxidation products paralleling reduced heart collagen content.It remains to be shown that the successful reduction of heart collagen by thiaproline is paralleled by improved functional properties.     

Construction and analysis of a recombination-deficient (radA) mutant of Haloferax volcanii

By deleting the radA open reading frame of an extreme halophile, Haloferax volcanii , we created and characterized a recombination-deficient archaeon. This strain, Hf. volcanii DS52, has no detectable DNA recombination, is more sensitive to DNA damage by UV light and ethylmethane sulfonate, and has a slower growth rate than the wild type. These characteristics are similar to those observed in recombination mutants of Eukarya and Bacteria, and show that the radA gene belongs in the recA / RAD51 family by function as well as sequence homology. In addition, strain DS52 was not transformable by plasmids pWL102 or pUBP2 (which contain pHV2 and pHH1 replicons, respectively), although it was readily transformed by plasmids containing a pHK2 replicon, indicating a role for radA in the maintenance or replication of some halobacterial plasmids. Despite its slower growth rate, Hf. volcanii DS52 was still easy to culture and transform, and should be suitable for use in studies where a recombination-deficient background is desired.     

The relationship between sporulation and solvent production in clostridium acetobutylicum P262

Summary Single and multiple Clostridium acetobutylicum P262 sporulation, clostridial stage, granulose, capsule and solvent producing mutants were isolated. Although common regulatory components were involved in the regulation of these events, each individual pathway was able to function independently of each other. Inhibitors of DNA replication inhibited spore formation but did not affect solvent, clostridial stage, granulose and capsule production.     

Non-ependymal cilia in the habenulae and the interpeduncular nucleus of the frog tadpole

Summary Cilia of the 9+2 pattern are found electron microscopically in nonependymal cells of the habenulae and the interpeduncular nucleus of the tadpole of Rana esculenta at an early stage of development (8 mm length, head to tip of tail). A comparison is made between these and the ependymal and sensory cilia in the same specimens. The cilia project into the neuropil emerging from a perikaryon rich in free ribosomes and displaying a prominent Golgi apparatus. These perikarya contain dense core vesicles. Synapses with vesicles of the clear spherical type have been observed along the ciliary shaft. On a purely morphologic basis the authors hypothesize that these cilia, at least in this early ontogenetic stage, may extend considerably the conducting surface of the cell and represent a sensory structure which could be stimulated by terminal processes belonging to distantly located cells. In addition, they could also be involved in the trophic exchange of material with the adjacent structures.