A Translation System Reconstituted with Human Factors Proves That Processing of Encephalomyocarditis Virus Proteins 2A and 2B Occurs in the Elongation Phase of Translation without Eukaryotic Release Factors

The genomic RNA of encephalomyocarditis virus (EMCV) encodes a single polyprotein, and the primary scission of the polyprotein occurs between nonstructural proteins 2A and 2B by an unknown mechanism. To gain insight into the mechanism of 2A-2B processing, we first translated the 2A-2B region in vitro with eukaryotic and prokaryotic translation systems. The 2A-2B processing occurred only in the eukaryotic systems, not in the prokaryotic systems, and the unprocessed 2A-2B protein synthesized by a prokaryotic system remained uncleaved when incubated with a eukaryotic cell extract. These results suggest that 2A-2B processing is a eukaryote-specific, co-translational event. To define the translation factors required for 2A-2B processing, we constituted a protein synthesis system with eukaryotic elongation factors 1 and 2, eukaryotic release factors 1 and 3 (eRF1 and eRF3), aminoacyl-tRNA synthetases, tRNAs, ribosome subunits, and a plasmid template that included the hepatitis C virus internal ribosome entry site. We successfully reproduced 2A-2B processing in the reconstituted system even without eRFs. Our results indicate that this unusual event occurs in the elongation phase of translation.     

Imidazopyridine derivatives as potent and selective Polo-like kinase (PLK) inhibitors

A novel class of imidazopyridine derivatives was designed as PLK1 inhibitors. Extensive SAR studies supported by molecular modeling afforded a highly potent and selective compound 36. Compound 36 demonstrated good antitumor efficacy in xenograft nude rat model.     

Genetic divergence between and within two color morphotypes of <Emphasis Type="Italic">Parapercis sexfasciata</Emphasis> (Perciformes: Pinguipedidae) from Tosa Bay,southern Japan

The anterior half of the mitochondrial DNA control region (mtCR) sequence (ca. 400 base pairs) was compared between two color morphotypes (A, B) of Parapercis sexfasciata from Tosa Bay, southern Japan, using 16 and 21 specimens, respectively. Intramorphotypic mtCR divergences were only 0.0–0.5% and 1.0–2.5% for morphotypes A and B, respectively. In contrast, intermorphotypic mtCR divergence was much greater, 12.7–14.0%. Furthermore, phylogenetic analysis using a neighbor-joining algorithm, with P. multifasciata as an outgroup, showed that each morphotype was reciprocally monophyletic. These results and the distinct coloration and overlapping distribution indicate that the two color morphotypes of P. sexfasciata represent two distinct species. Mismatch distribution analysis suggested that both morphotypes had undergone population expansion; however, estimates of initial population sizes and mutational timescales suggested that morphotype B comprises historically larger and older populations than morphotype A.     

Circadian rhythm of intracellular protein synthesis signaling in rat cardiac and skeletal muscles

Intracellular signaling exhibits circadian variation in the suprachiasmatic nucleus and liver. However, it is unclear whether circadian regulation also extends to intracellular signaling pathways in the cardiac and skeletal muscles. Here, we examined circadian variation in the intracellular mammalian target of rapamycin (mTOR)/70 kDa ribosomal protein S6 kinase 1 (p70S6K) and extracellular signal-regulated kinase (ERK) pathways, which regulate protein synthesis in rat cardiac and skeletal muscles. Seven-week-old male Wistar rats were assigned to six groups: Zeitgeber time (ZT) 2, ZT6, ZT10, ZT14, ZT18, and ZT22 (ZT0, lights on; ZT12, lights off). The cardiac, plantaris, and soleus muscles were removed after a 12-h fasting period, and signal transducers involved in protein synthesis (mTOR, p70S6K, and ERK) were analyzed by western blotting. Circadian rhythms of signal transducers were observed in both cardiac (mTOR, p70S6K, and ERK) and plantaris (p70S6K and ERK) muscles (p<0.05), but not in the soleus muscle. In the cardiac muscle, the phosphorylation rate of mTOR was significantly higher at ZT6 (peak) than at ZT18 (bottom), and the phosphorylation rate of p70S6K was significantly higher at ZT2 (peak) than at ZT18 (bottom). In contrast, in the plantaris muscle, the phosphorylation rate of ERK was significantly lower at ZT2 (bottom) than at ZT18 (peak). Our data suggested that protein synthesis via mTOR/p70S6K and ERK signaling molecules exhibits circadian variation in rat cardiac and fast-type plantaris muscles.     

Production and Properties of Alkaline Lipase from Alcaligenes sp. Strain No. 679

For the production of extracellular lipase by Alcaligenes species No. 679, NaNO₃, polyoxyethylene alkyl ether, Fe⁺⁺, sodium citrate and fructose were found to be effective. The enzyme was prepared by acetone precipitation from the filtrate of the culture broth of this strain. The enzyme was most active at pH 9.0 and 50°C, while 35% of its activity was lost on heat treatment at 60°C for 10 min. Sodium salts of bile acids stimulated the enzyme activity. This lipase could hydrolyse natural fats and oils as well as olive oil. During the hydrolysis of olive oil, monoglyceride was found to accumulate up to 70 mol percent. This lipase possesses special properties similar to those of pancreatic lipase as shown in the comparative experiments.     

Two intromittent organs in Zorotypus caudelli (Insecta,Zoraptera): the paradoxical coexistence of an extremely long tube and a large spermatophore

Very unusual genitalia of the species Zorotypus caudelli are described. It contains the unique configuration of two different intromittent organs, one of them strongly elongated. Hyper elongated genitalia are known in different groups of insects. Males have to accommodate these unwieldy structures in the limited spaces of the abdomen and manipulate them acutely during copulation. A crucial question is how do species with elongated genitalia cope with these requirements? To investigate this, we studied key features enabling storage, insertion, and withdrawal of the elongated genitalia. The co‐existence of an elongated narrow tube and a bulky spermatophore is a highly unusual and apparently paradoxical condition. However, we demonstrate that the tube is not involved in sperm transmission, whereas the large spermatophore is transferred to females by a membranous fold of the genitalia. The movement of the spermatophore is caused by haemolymph pressure, which likely also promotes the insertion of both intromittent organs. A comparison with the genital anatomy and reproductive mode in related groups suggests that the elongated tube and its accommodating pouch is a de novo structure, and that the ancestral sperm transport via spermatophore is a preadaptive condition for the acquisition of this unusual structure. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 40–54.