Further Obervations on the Use of the Medicinal Plant, Vernonia amygdalina (Del). By a Wild Chimpanzee, Its Possible Effect on Parasote Load, and Its Phytochemistry

This is the second detailed case study of the use of V. amygdalina (Del) by a wild chimpanzee suffering from gastrointestinal upset (flatulence and diarrhea). The female, who was followed for approximately 5 hours over a two-day period, recovered from her symptoms by the afternoon of the second day. Laboratory examination of two decal samples, one collected approximately 1 hour and another 20.5 hours after ingestion of the plant's bitter pith, revealed a notable drop in the degree of parasitic infection by a Ternidens sp. Bioassay of the plant consumed by the female confirmed that the two most abundant and bioactive constituents, vernodalin and vernonioside B1, were present. Vernonioside B1 was found to occur at significant levels in both the leaves and pith, but the cytotoxic vernodalin was found only in the leaves. This suggests that vernonioside B1 and its naturally occurring aglycones are likely to be the bioactive constituents ingested by chimpanzees. The estimated amount of vernonioside B1 ingested by this female was found to be approximately equal to the amount contained in a traditional Tongwe medicinal preparation from a cold water extract of the leaves to treat similar gastrointestinal disorders in adult human patients. This report provides new evidence for the effectiveness of medicinal plant use in primates and strongly supports the current hypothesis regarding the use of V. amygdalina for the control of symptoms from parasitic and gastrointestinal illness by wild chimpanzees

Role of the RNA-binding Protein Nrd1 and Pmk1 Mitogen-activated Protein Kinase in the Regulation of Myosin mRNA Stability in Fission Yeast

Myosin II is an essential component of the actomyosin contractile ring and plays a crucial role in cytokinesis by generating the forces necessary for contraction of the actomyosin ring. Cdc4 is an essential myosin II light chain in fission yeast and is required for cytokinesis. In various eukaryotes, the phosphorylation of myosin is well documented as a primary means of activating myosin II, but little is known about the regulatory mechanisms of Cdc4. Here, we isolated Nrd1, an RNA-binding protein with RNA-recognition motifs, as a multicopy suppressor of cdc4 mutants. Notably, we demonstrated that Nrd1 binds and stabilizes Cdc4 mRNA, thereby suppressing the cytokinesis defects of the cdc4 mutants. Importantly, Pmk1 mitogen-activated protein kinase (MAPK) directly phosphorylates Nrd1, thereby negatively regulating the binding activity of Nrd1 to Cdc4 mRNA. Consistently, the inactivation of Pmk1 MAPK signaling, as well as Nrd1 overexpression, stabilized the Cdc4 mRNA level, thereby suppressing the cytokinesis defects associated with the cdc4 mutants. In addition, we demonstrated the cell cycle–dependent regulation of Pmk1/Nrd1 signaling. Together, our results indicate that Nrd1 plays a role in the regulation of Cdc4 mRNA stability; moreover, our study is the first to demonstrate the posttranscriptional regulation of myosin expression by MAPK signaling