The target of rapamycin (TOR) proteins

Rapamycin potently inhibits downstream signaling from the target of rapamycin (TOR) proteins. These evolutionarily conserved protein kinases coordinate the balance between protein synthesis and protein degradation in response to nutrient quality and quantity. The TOR proteins regulate (i) the initiation and elongation phases of translation, (ii) ribosome biosynthesis, (iii) amino acid import, (iv) the transcription of numerous enzymes involved in multiple metabolic pathways, and (v) autophagy. Intriguingly, recent studies have also suggested that TOR signaling plays a critical role in brain development, learning, and memory formation.

Differential expression of the ToxR regulon in classical and E1 Tor biotypes of Vibrio cholerae is due to biotype-specific control over toxT expression.

The two major disease-causing biotypes of Vibrio cholerae, classical and El Tor, exhibit differences in their epidemic nature. Their behavior in the laboratory also differs in that El Tor strains produce two major virulence factors, cholera toxin (CT) and the toxin coregulated pilus (TCP), only under very restricted growth conditions, whereas classical strains do so in standard laboratory medium. Expression of toxin and TCP is controlled by two activator proteins, ToxR and ToxT, that operate in cascade fashion with ToxR controlling the synthesis of ToxT. Both biotypes express equivalent levels of ToxR, but only classical strains appear to express ToxT when grown in standard medium. In this report we show that restrictive expression of CT and TCP can be overcome in El Tor strains by expressing ToxT independently of ToxR. An El Tor strain lacking functional ToxT does not express CT or TCP, ruling out existence of a cryptic pathway for virulence regulation in this biotype. These results may have implications for understanding the evolution of El Tor strains toward reduced virulence with respect to classical strains.

Matlock Tor by Moonlight

Joseph Wright; 2 ft. 2 in.x 2 ft. 6 in.; oil on canvas

Norsk meteorologisk aarbok.

Vols. for 1868-73 called "2.-7. aarg."

Dansk-norsk litteraturlexicon ...

Title of v. 2 varies slightly.

Norsk magazin for lægevidenskaben.

Subtitle varies.

Norsk forfatter-lexikon, 1814-1880. Paa grundlag

Vol. 6: Fuldført af Halvdan Koht.

Norsk geologisk tidsskrift

Mode of access: Internet.

Norsk blandkorn ...

Mode of access: Internet.