Comparative expression of soluble, active human kinases in specialized bacterial strains.

Kinases act as molecular switches for cellular functions and are involved in multiple human pathogeneses, most notably cancer. There is a continuous need for soluble and active kinases for in-vitro drug discovery and structural biology purposes. Kinases remain challenging to express using Escherichia coli, the most widely utilized host for heterologous expression. In this work, four bacterial strains, BL21 (DE3), BL21 (DE3) pLysS, Rosetta, and Arctic Express, were chosen for parallel expression trials along with BL21 (DE3) complemented with folding chaperones DnaJ/K and GroEL/ES to compare their performance in producing soluble and active human kinases. Three representative diverse kinases were studied, Epidermal Growth Factor Receptor kinase domain, Aurora Kinase A kinase domain, and Mitogen-activated protein Kinase Kinase. The genes encoding the kinases were subcloned into pET15b bacterial plasmid and transformed into the bacterial strains. Soluble kinase expression was tested using different IPTG concentrations (1-0.05 mM) at varying temperatures (37°C- 10°C) and induction times (3-24 hours). The optimum conditions for each kinase in all strains were then used for 1L large scale cultures from which each kinase was purified to compare yield, purity, oligomerization status, and activity. Although using specialized strains achieved improvements in yield and/or activity for the three kinases, none of the tested strains was universally superior, highlighting the individuality in kinase expression.

Anticoagulation Strategies in the Management of Lemierre Syndrome: A Systematic Review of the Literature.

OBJECTIVE: To determine the optimal anticoagulation strategy in patients diagnosed with Lemierre Syndrome (LS). DATA SOURCES: A systematic review in accordance with PRISMA guidelines was conducted using PubMed, MEDLINE, Scopus, ProQuest, and CINAHL from January to April 2020. Search terms included "Lemierre Syndrome" AND "anticoagulation" NOT "prophylaxis" OR "atrial fibrillation," in addition to a list of parenteral and oral anticoagulants. Adult patients who developed a clot and required systemic anticoagulation as a result of LS were included in this review. STUDY SELECTION AND DATA EXTRACTION: A total of 4180 records were initially identified, though following the removal of duplicates and nonrelevant entries, 216 full-text articles were reviewed for inclusion; 13 articles were ultimately included. DATA SYNTHESIS: The majority (11/14) of patients developed thromboses of the internal jugular veins, which corresponds to the pathophysiology of LS. Anticoagulation strategies were varied in the included literature, though 12/14 patients initially received a parenteral product. Two patients received a direct-acting oral anticoagulant (DOAC) following either intravenous heparin or subcutaneous enoxaparin and had outcomes similar to patients transitioned to warfarin. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Anticoagulation in LS is a clinical controversy because the thromboembolic events have rarely led to significant complications; thrombi typically resolve independently, and concerns for bleeding risks are well founded; however, this review indicates both the efficacy and safety of anticoagulation. CONCLUSIONS: Anticoagulation is both efficacious and safe in LS, including treatment using a DOAC. Although further studies are needed, clinicians should consider a duration of anticoagulation of 6 to 12 weeks.