Molecular characterization of Lyme disease spirochetes (Borrelia burgdorferi sensu lato) isolated in Taiwan by restriction fragment length polymorphism analysis of 5S(rrf)-23S(rrl) intergenic spacer amplicons

We analyzed the 5S (rrf)-23S (rrl) intergenic spacer amplicon gene of Lyme disease spirochetes (Borrelia burgdorferi sensu lato) for the first time in Taiwan. The genetic identities of these Taiwan isolates (TWKM1-7) were clarified by comparing their restriction fragment length polymorphism patterns and sequence similarities of the polymerase chain reaction-amplified intergenic spacer amplicon genes with 3 major genospecies of Lyme disease spirochetes. Amplified-spacer DNAs were purified further and subjected to the cleavage by nuclease DraI or MseI. Differential fragment patterns in relation to different genospecies of Lyme disease spirochetes were observed among tested Borrelia isolates, and all of these Taiwan isolates were closely related to the genospecies of B. burgdorferi sensu stricto. The phylogenetic analysis also revealed that the sequence similarity of polymerase chain reaction-amplified spacer genes of these Taiwan isolates was highly homogeneous (95.7-100%) within the genospecies of B. burgdorferi sensu stricto and can be distinguished clearly from other genospecies of Lyme disease spirochetes with a 4.1% sequence divergence. Based on the differential fragment patterns and sequence similarity among these Taiwan isolates, the genetic identity of these Taiwan isolates should be classified into the genospecies of B. burgdorferi sensu stricto.     

Timing-dependent reduction in ethanol sedation and drinking preference by NMDA receptor co-agonist d-serine

NMDA receptors become a major contributor to acute ethanol intoxication effects at high concentrations as ethanol binds to a unique site on the receptor and inhibits glutamatergic activity in multiple brain areas. Although a convincing body of literature exists on the ability of NMDA receptor antagonists to mimic and worsen cellular and behavioral ethanol effects, receptor agonists have been less well-studied. In addition to a primary agonist site for glutamate, the NMDA receptor contains a separate co-agonist site that responds to endogenous amino acids glycine and d-serine. d-serine is both selective for this co-agonist site and potent in boosting NMDA dependent activity even after systemic administration. In this study, we hypothesized that exogenous d-serine might ameliorate some acute ethanol behaviors by opposing NMDA receptor inhibition. We injected adult male C57 mice with a high concentration of d-serine at various time windows relative to ethanol administration and monitored sedation, motor coordination and voluntary ethanol drinking. d-serine (2.7 g/kg, ip) prolonged latency to a loss of righting reflex (LoRR) and shortened LoRR duration when given 15 min before ethanol (3 g/kg) but not when it was injected with or shortly after ethanol. Blood samples taken at sedative recovery and at fixed time intervals revealed no effect of d-serine on ethanol concentration but an ethanol-induced decrease in l-serine and glycine content was prevented by acute d-serine pre-administration. d-serine had no effect on ethanol-induced (2 g/kg) rotarod deficits in young adult animals but independently and interactively degraded motor performance in a subset of older mice. Finally, a week-long series of daily ip injections resulted in a 50% decrease in free choice ethanol preference for d-serine treated animals compared to saline-injected controls in a two-bottle choice experiment.