Anesthetic Challenges Posed by Heavy Kratom Users.

Kratom is a herbal and natural dietary supplement from Southeast Asia that is gaining popularity in the United States. Its leaves contain multiple psychoactive chemicals that stimulate opioid, alpha-2, and serotonergic receptors. Kratom is used as a stimulant and in the treatment of anxiety, pain, and opioid withdrawal. In most states, kratom can be purchased legally and is sold at smoke shops, gas stations, and online. To date, only limited data is available on the impact of habitual kratom use on patients undergoing anesthesia. The following case report highlights multiple anesthetic challenges posed by a heavy kratom user.

Hydrophobic carboxy-terminal residues dramatically reduce protein levels in the haloarchaeon Haloferax volcanii.

Proteolysis is important not only to cell physiology but also to the successful development of biocatalysts. While a wide-variety of signals are known to trigger protein degradation in bacteria and eukaryotes, these mechanisms are poorly understood in archaea, known for their ability to withstand harsh conditions. Here we present a systematic study in which single C-terminal amino acid residues were added to a reporter protein and shown to influence its levels in an archaeal cell. All 20 amino acid residues were examined for their impact on protein levels, using the reporter protein soluble modified red-shifted GFP (smRS-GFP) expressed in the haloarchaeon Haloferax volcanii as a model system. Addition of hydrophobic residues, including Leu, Cys, Met, Phe, Ala, Tyr, Ile and Val, gave the most pronounced reduction in smRS-GFP levels compared with the addition of either neutral or charged hydrophilic residues. In contrast to the altered protein levels, the C-terminal alterations had no influence on smRS-GFP-specific transcript levels, thus revealing that the effect is post-transcriptional.