|
|
|
|
|
|
Distribution of Amphotericin B-Arabinogalactan Conjugate in Mouse Tissue and Its Therapeutic Efficacy against Murine Aspergillosis. Rama Falk, 2004.The pharmacokinetic characteristics and tissue distribution of a novel water-soluble, nontoxic amphotericin B-arabinogalactan (AMB-AG) conjugate exhibited distinct differences from those of micellar and liposomal amphotericin B formulations . These differences included extended persistence of drug in the body and its accumulation in the lungs; thus, the AMB-AG conjugate was highly effective in treating systemic murine aspergillosis . Characterization of a Galactokinase-Positive Recombinant Strain of Streptococcus thermophilus. Katy Vaillancourt, 2004.The lactic acid bacterium Streptococcus thermophilus is widely used by the dairy industry for its ability to transform lactose, the primary sugar found in milk, into lactic acid . Unlike the phylogenetically related species Streptococcus salivarius, S . thermophilus is unable to metabolize and grow on galactose and thus releases substantial amounts of this hexose into the external medium during growth on lactose . This metabolic property may result from the inability of S . thermophilus to synthesize galactokinase, an enzyme of the Leloir pathway that phosphorylates intracellular galactose to generate galactose-1-phosphate . In this work, we report the complementation of Gal– strain S . thermophilus SMQ-301 with S . salivarius galK, the gene that codes for galactokinase, and the characterization of recombinant strain SMQ-301K01 . The recombinant strain, which was obtained by transformation of strain SMQ-301 with pTRKL2TK, a plasmid bearing S . salivarius galK, grew on galactose with a generation time of 55 min, which was almost double the generation time on lactose . Data confirmed that (i) the ability of SMQ-301K01 to grow on galactose resulted from the expression of S . salivarius galK and (ii) transcription of the plasmid-borne galK gene did not require GalR, a transcriptional regulator of the gal and lac operons, and did not interfere with the transcription of these operons . Unexpectedly, recombinant strain SMQ-301K01 still expelled galactose during growth on lactose, but only when the amount of the disaccharide in the medium exceeded 0.05% . Thus, unlike S . salivarius, the ability to metabolize galactose was not sufficient for S . thermophilus to simultaneously metabolize the glucose and galactose moieties of lactose . Nevertheless, during growth in milk and under time-temperature conditions that simulated those used to produce mozzarella cheese, the recombinant Gal+ strain grew and produced acid more rapidly than the Gal– wild-type strain . Ultrastructural Analysis of Differentiation in Legionella pneumophila. Gary Faulkner, 2002. The NorM Efflux Pump of Neisseria gonorrhoeae and Neisseria meningitidis Recognizes Antimicrobial Cationic Compounds. Corinne Rouquette-Loughlin, 2003.In Neisseria gonorrhoeae and Neisseria meningitidis, we identified a gene that would encode a protein highly similar to NorM of Vibrio parahaemolyticus (Y . Morita et al., Antimicrob . Agents Chemother . 42:1778-1782, 1998) . A nonpolar insertional mutation in either the gonococcal or meningococcal norM gene resulted in increased bacterial sensitivity to compounds harboring a quaternary ammonium on an aromatic ring (e.g., ethidium bromide, acriflavine hydrochloride, 2-N-methylellipticinium, and berberine) . The presence of point mutations within the -35 region of a putative norM promoter or a likely ribosome binding site resulted in an increased resistance of gonococci and meningococci to the same compounds, as well as to norfloxacin and ciprofloxacin . Structure-activity relationship studies with putative NorM substrates have found that a cationic moiety is essential for NorM recognition .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
