Ultrahigh Throughput Evolution of Tryptophan Synthase in Droplets via an Aptamer Sensor

Tryptophan synthase catalyzes the synthesis of a wide array of noncanonical amino acids and is an attractive target for directed evolution. Droplet microfluidics offers an ultrahigh throughput approach to directed evolution (up to 107 experiments per day), enabling the search for biocatalysts in wider regions of sequence space with reagent consumption minimized to the picoliter volume (per library member). While the majority of screening campaigns in this format on record relied on an optically active reaction product, a new assay is needed for tryptophan synthase. Tryptophan is not fluorogenic in the visible light spectrum and thus falls outside the scope of conventional droplet microfluidic readouts, which are incompatible with UV light detection at high throughput. Here, we engineer a tryptophan DNA aptamer into a sensor to quantitatively report on tryptophan production in droplets. The utility of the sensor was validated by identifying five-fold improved tryptophan synthases from ∼100,000 protein variants. More generally, this work establishes the use of DNA-aptamer sensors with a fluorogenic read-out in widening the scope of droplet microfluidic evolution.

[Covered uterine rupture in uterus bicornis with placenta increta. A case report]

The case of a woman patient of 30 years of age is reported in whom spontaneous rupture of the uterus occurred in the 22nd week of pregnancy due to a uterus bicornis with placenta increta. The very rare disease pattern, which is often associated with many complications, of a disturbance of implantation of the placenta, often demands immediate surgery and can mostly be diagnosed only retrospectively. Hence, an early recognition method would be desirable. Basing on the literature, the significant rôle played by sonographic diagnosis in this connection is pointed out.

[Hysterosalpingectomy. A contribution to the prevention of primary tubal neoplasms]

Reporting on 5103 hysterectomies performed within a period of 8 years (1970-1977), with a persistent high frequency of the vaginal approach (93,0%) independent of the dignity of the disease, the importance of a simultaneous bilateral salpingectomy is emphasized. Age and parity of the patients as well as size of uterus and indication for surgery were of little influence on the mode of operation. 3 carcinomas of the uterine tube, i.e. 0,43% of all gynecological neoplasms in our collective and a total of 701 other genital carcinoma were treated. With reference to current literature the clinical problems of primary malignant tumors of the uterine tube are discussed and the 3 cases of preoperatively undetected carcinoma are presented to underline the diagnostic and prognostic complexity. As a prophylactic measure hysterosalpingectopmy is recommmended for every uterus extirpation.

Acute metabolic responses to myocardial infarction. Changes in glucose utilization and secretion of insulin and growth hormone

Glucose utilization and secretion of insulin and growth hormone after intravenous administration of glucose were measured during the evolution of myocardial infarctions. Two patterns of responses were found. Patients who developed myocardial infarction with either no prior cardiovascular disease or stable coronary artery disease had depressed glucose utilization for the first 48 hours and exhibited a hyperinsulinemic response to glucose during the sixth to fourteenth day; and, about 50% of them, had an increase in the secretion of growth hormone during the initial 4 days of the infarction. Patients who had had progressively increasing angina in the 7 to 14 days preceding infarction showed a different pattern. No initial depression of glucose utilization was found. Their hyperinsulinemic response occurred within the first 96 hours of the occlusion. Growth hormone secretion was increased in 83% of the patients during the first 96 hours. The data suggest the possibility that the exaggerated insulin secretion may be associated with myocardial repair processes while the changes in growth hormone secretion may be related to the acute stress or necrosis of the infarction.