Functional consequences of treating turkey liver fructose-1,6-bisphosphatase with penicillin G.

Treatment of turkey liver fructose-1,6--bisphosphatase with penicillin G progressively inactivated the enzyme and desensitized the enzyme toward high substrate inhibition. The treatment also led to reduced sensitivity to AMP inhibition and the loss of cooperative interaction among AMP-binding sites. These altered properties were not reversed by dialysis, but were prevented when treatment with penicillin G was perfomed in the presence of substrate.     

High frequency of BRAF mutations in nevi

To evaluate the timing of mutations in BRAF (v-raf murine sarcoma viral oncogene homolog B1) during melanocytic neoplasia, we carried out mutation analysis on microdissected melanoma and nevi samples. We observed mutations resulting in the V599E amino-acid substitution in 41 of 60 (68%) melanoma metastases, 4 of 5 (80%) primary melanomas and, unexpectedly, in 63 of 77 (82%) nevi. These data suggest that mutational activation of the RAS/RAF/MAPK pathway in nevi is a critical step in the initiation of melanocytic neoplasia but alone is insufficient for melanoma tumorigenesis.     

Effect of 17 β-estradiol on early cleavage patterns in the embryo ofFucus distichus

Zusammenfassung 17-Östradiol verändert die Lage der Spindelachse und verursacht eine abnormale Mitose in jungen Embryonen vonFucus distichus. In der Folge zeigen die wachsenden Embryonen Furchungsmuster, welche keine geordnete Abfolge der Teilungen mehr zeigen. Trotzdem können die Embryonen eine örtliche Polarisierung aufrecht erhalten und überleben.