Thermostable in vitro transcription-translation compatible with microfluidic droplets.

BACKGROUND: In vitro expression involves the utilization of the cellular transcription and translation machinery in an acellular context to produce one or more proteins of interest and has found widespread application in synthetic biology and in pharmaceutical biomanufacturing. Most in vitro expression systems available are active at moderate temperatures, but to screen large libraries of natural or artificial genetic diversity for highly thermostable enzymes or enzyme variants, it is instrumental to enable protein synthesis at high temperatures. OBJECTIVES: Develop an in vitro expression system operating at high temperatures compatible with enzymatic assays and with technologies that enable ultrahigh-throughput protein expression in reduced volumes, such as microfluidic water-in-oil (w/o) droplets. RESULTS: We produced cell-free extracts from Thermus thermophilus for in vitro translation including thermostable enzymatic cascades for energy regeneration and a moderately thermostable RNA polymerase for transcription, which ultimately limited the temperature of protein synthesis. The yield was comparable or superior to other thermostable in vitro expression systems, while the preparation procedure is much simpler and can be suited to different Thermus thermophilus strains. Furthermore, these extracts have enabled in vitro expression in microfluidic droplets at high temperatures for the first time. CONCLUSIONS: Cell-free extracts from Thermus thermophilus represent a simpler alternative to heavily optimized or pure component thermostable in vitro expression systems. Moreover, due to their compatibility with droplet microfluidics and enzyme assays at high temperatures, the reported system represents a convenient gateway for enzyme screening at higher temperatures with ultrahigh-throughput.

Extrapyramidal adverse events and anticholinergics use after the long-term treatment of patients with schizophrenia with the new long-acting antipsychotic Risperidone ISM®: results from matching-adjusted indirect comparisons versus once-monthly formulations of Paliperidone palmitate and Aripiprazole monohydrate in 52-week studies.

BACKGROUND: Risperidone ISM® is a newly developed long-acting injectable (LAI) treatment for schizophrenia in adults. In the absence of head-to-head comparisons with other similar antipsychotics, the objective of this study was to generate indirect evidence of some aspects of the safety and tolerability of Risperidone ISM compared to other LAI antipsychotics for treatment of patients with schizophrenia in the maintenance treatment setting. METHODS: A literature review was conducted systematically to identify maintenance treatment studies reporting safety and tolerability outcomes for LAI antipsychotic therapies. Following an assessment of between-trial heterogeneity, a matching-adjusted indirect comparison (MAIC) was performed to account for between-trial imbalances in patient characteristics and to generate comparative evidence for safety and tolerability endpoints. RESULTS: The analysis showed that incidence of extrapyramidal symptoms (EPS) was found to be numerically, but not statistically significantly, lower in patients receiving Risperidone ISM than in those receiving Paliperidone palmitate (PP) (OR [95% CI] 0.63 [0.29, 1.38], p = 0.253) and statistically significantly lower than with Aripiprazole monohydrate once-monthly (AOM) (OR [95% CI] 0.25 [0.12, 0.53], p < 0.001). Use of anticholinergic agents for the alleviation of EPS was also shown to be significantly lower in Risperidone ISM patients than in those receiving PP (OR [95% CI] 0.29 [0.10, 0.83], p = 0.021) or AOM (OR [95% CI] 0.01 [0.003, 0.06], p < 0.001), suggesting a superior tolerability profile for clinically relevant EPS. Results from the sensitivity analyses comparing stabilized and stable patients receiving Risperidone ISM to those receiving AOM yielded similarly favorable conclusions in line with the base case analyses. CONCLUSIONS: This MAIC is consistent with the safety and tolerability results obtained during the PRISMA-3 clinical trial in the long-term treatment of schizophrenia and suggests a favorable safety and tolerability profile in terms of EPS incidence and anticholinergic agent use, relative to other antipsychotic therapies used for treatment of patients with schizophrenia in the maintenance setting.

Thermus thermophilus nucleoside phosphorylases active in the synthesis of nucleoside analogues.

Cells extracts from Thermus thermophilus HB27 express phosphorolytic activities on purines and pyrimidine nucleosides. Five putative encoding genes were cloned and expressed in Escherichia coli, and the corresponding recombinant proteins were purified and studied. Two of these showed phosphorolytic activities against purine nucleosides, and third one showed phosphorolytic activity against pyrimidine nucleosides in vitro, and the three were named TtPNPI, TtPNPII, and TtPyNP, respectively. The optimal temperature for the activity of the three enzymes was beyond the water boiling point and could not be measured accurately, whereas all of them exhibited a wide plateau of optimal pHs that ranged from 5.0 to 7.0. Analytical ultracentrifugation experiments revealed that TtPNPI was a homohexamer, TtPNPII was a monomer, and TtPyNP was a homodimer. Kinetic constants were determined for the phosphorolysis of the natural substrates of each enzyme. Reaction tests with nucleoside analogues revealed critical positions in the nucleoside for its recognition. Activities with synthetic nucleobase analogues, such as 5-iodouracil or 2,6-diaminopurine, and arabinosides were detected, supporting that these enzymes could be applied for the synthesis of new nucleoside analogs with pharmacological activities.

Thermus thermophilus strains active in purine nucleoside synthesis.

Several strains of Thermus thermophilus were tested in order to detect purine nucleoside synthase activity using pyrimidine nucleosides as the sugar-donor and adenine or hypoxanthine as bases. High productivity values (t =1 hr) were obtained while completely avoiding adenosine-deaminase degradation of the products. N-2-deoxy-ribosyltransferase activity is described for the first time in hyperthermophilic bacteria.