|
|
|
|
|
|
Characterization of Tn916S, a Tn916-Like Element Containing the Tetracycline Resistance Determinant tet(S). Holli Lancaster, 2004.We have characterized a transferable tetracycline resistance (Tcr) element from a Streptococcus intermedius isolate . The gene responsible for this resistance was identified by PCR and Southern hybridization as tet(S) . Furthermore, the genetic support for this determinant was shown to be a conjugative transposon closely related to Tn916 . This element has been designated Tn916S . Novel Antimalarial Compounds Isolated in a Survey of Self-Medicative Behavior of Wild Chimpanzees in Uganda. Sabrina Krief, 2004.Following a veterinary and behavioral survey of chimpanzees from a natural population in Uganda, leaf samples of Trichilia rubescens were collected because of the unusual method of ingestion observed . The methanolic crude extract of T . rubescens leaves exhibited significant antimalarial activity in vitro . Bioassay-directed fractionation provided two new limonoids, trichirubines A and B . A greater understanding of the role of secondary compounds in the primate diet may be helpful in recovering naturally occurring compounds of medicinal significance for human medicine . Substrate Specificity of the AmpG Permease Required for Recycling of Cell Wall Anhydro-Muropeptides. Qiaomei Cheng, 2002.AmpG was originally identified as a gene required for induction of ß-lactamase . Subsequently, we found AmpG to be a permease required for recycling of murein tripeptide and uptake of anhydro-muropeptides . We have now studied the specificity of the AmpG permease . The principal requirement is for the presence of the disaccharide, N-acetylglucosaminyl-ß-1,4-anhydro-N-acetylmuramic acid (GlcNAc-anhMurNAc) . These unique substrates for AmpG, which contain murein peptides linked to GlcNAc-anhMurNAc, are produced by turnover of the cell wall during logarithmic growth . AmpG permease is sensitive to carbonylcyanide m-chlorophenylhydrazone, demonstrating that AmpG permease is a single-component permease and that transport is dependent on the proton motive force . Role for Mannose-Sensitive Hemagglutinin in Promoting Interactions between Vibrio cholerae El Tor and Mussel Hemolymph. Massimiliano Zampini, 2003.The role of mannose-sensitive hemagglutinin (MSHA) in Vibrio cholerae O1 El Tor interactions with hemolymph of the mussel Mytilus galloprovincialis was studied . Bacterial adherence to and association with hemocytes were evaluated at 4 and 18°C, respectively . In hemolymph serum, the wild-type strain N16961 adhered to and associated with hemocytes about twofold more efficiently than its mutant lacking MSHA . In artificial seawater (ASW), no significant differences between the two strains were observed . N16961 was also more sensitive to hemocyte bactericidal activity than its MSHA mutant; in fact, the percentages of killed bacteria after 120 min of incubation were 60 and 34%, respectively . The addition of D-mannose abolished the serum-mediated increase in adherence, association, and sensitivity to killing of the wild-type strain without affecting the interactions of the mutant . A similar increase in N16961 adherence to hemocytes was observed when serum was adsorbed with MSHA-deficient bacteria . In contrast, serum adsorbed with either wild-type V . cholerae El Tor or wild-type Escherichia coli carrying type 1 fimbriae was no longer able to increase adherence of N16961 to hemocytes . The results indicate that hemolymph-soluble factors are involved in interactions between hemocytes and mannose-sensitive adhesins .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
