Drug-induced cell cycle modulation leading to cell-cycle arrest, nuclear mis-segregation, or endoreplication

<p>Abstract</p> <p>Background</p> <p>Cancer cell responses to chemotherapeutic agents vary, and this may reflect different defects in DNA repair, cell-cycle checkpoints, and apoptosis control. Cytometry analysis only quantifies dye-incorporation to examine DNA content and does not reflect the biological complexity of the cell cycle in drug discovery screens.</p> <p>Results</p> <p>Using population and time-lapse imaging analyses of cultured immortalized cells expressing a new version of the fluorescent cell-cycle indicator, Fucci (<it>F</it>luorescent <it>U</it>biquitination-based <it>C</it>ell <it>C</it>ycle <it>I</it>ndicator), we found great diversity in the cell-cycle alterations induced by two anticancer drugs. When treated with etoposide, an inhibitor of DNA topoisomerase II, HeLa and NMuMG cells halted at the G₂/M checkpoint. HeLa cells remained there, but NMuMG cells then overrode the checkpoint and underwent nuclear mis-segregation or avoided the checkpoint and entered the endoreplication cycle in a drug concentration dependent manner. In contrast, an inhibitor of Cdk4 led to G₁arrest or endoreplication in NMuMG cells depending upon the initial cell-cycle phase of drug exposure.</p> <p>Conclusions</p> <p>Drug-induced cell cycle modulation varied not only between different cell types or following treatment with different drugs, but also between cells treated with different concentrations of the same drug or following drug addition during different phases of the cell cycle. By combining cytometry analysis with the Fucci probe, we have developed a novel assay that fully integrates the complexity of cell cycle regulation into drug discovery screens. This assay system will represent a powerful drug-discovery tool for the development of the next generation of anti-cancer therapies.</p

金魚の王様と言われている「らんちう」の語源について：「らんちう」とは何語なのか、どんな意味があるのか

Many people know that there is a goldfish named “ranchu（らんちう）” in Japan. It is the kind of non-dorsalfin fish, egg shape one, but said to be King of the goldfish. When you purchase this, it becomes the good price. However, nobody knows a word this “ranchu” is the word of any country, nor the meaning of it. I aimed at solving this myself in this study. Goldfish is an ornamental fish made artificially in China. The original goldfish which were in Japan in Edo era were brought all in from China. However, “ranchu” is a kind with a unique Quality created in Japan. This kind was made in the Meiji era. but we name the modern “ranchu” after the name reached Japan in the Edo era. Modern “ranchu” is different from “ranchu” of the Edo era for a kind. But they have the same name. In this study, I examined what you meant by this name that came in the Edo era. In a picture book of the Edo era, there is a commentary to call a goldfish without the dorsal fin both 〈ranchu〉 and 〈danchu〉. In this study, I paid my attention to this point and developed the reasoning. I looked for a kanji (Chinese character) based on a promise that the name “ranchu” could be brought from Chinese. Because 〈ran〉 and 〈dan〉 sound sometime exactly the same to our Japanese, I looked for a kanji which have the similar pronunciation with 〈ran〉 and 〈dan〉 and have the valuable meaning. As a result, I found a Word “蚤”, which means egg with shell like duck egg. In addition, about 〈chu〉, I found the word “種”, which means kind. From this consideration, the etymology of “ranchu” is found to be a southern Chinese pronunciation such as Cantonese of the word “蚤種“. This “蚤種”is used as one of the classifications of the kind of the goldfish in China. It would be suitable as a name of the goldfish without the dorsal fin in the 18th century. In addition, it is thought that various words used as a kanji to express “ranchu” in Japanese are substitute characters devised in Japan by pronunciation called “ranchu”

Engineered Mutants of a Marine Photosynthetic Purple Nonsulfur Bacterium with Increased Volumetric Productivity of Polyhydroxyalkanoate Bioplastics

Polyhydroxyalkanoates (PHAs) are green and sustainable bioplastics that could replace petrochemical synthetic plastics without posing environmental threats to living organisms. In addition, sustainable PHA production could be achieved using marine photosynthetic purple nonsulfur bacteria (PNSBs) that utilize natural seawater, sunlight, carbon dioxide gas, and nitrogen gas for growth. However, PHA production using marine photosynthetic PNSBs has not been economically feasible yet due to its high cost and low productivity. In this work, strain improvement, using genome-wide mutagenesis coupled with high-throughput screening via fluorescence-activated cell sorting, we were able to create Rhodovulum sulfidophilum mutants with enhanced volumetric PHA productivity, with an up to 1.7-fold increase. The best selected mutants (E6 and E6M4) reached the stationary growth phase 1 day faster and accumulated the maximum PHA content 2 days faster than the wild type. Maximizing volumetric PHA productivity before the stationary growth phase is indeed an additional advantage for R. sulfidophilum as a growth-associated PHA producer

Changes of optical properties of retroreflector installed in LHD

This article describes changes of optical properties of retroreflectors installed on the inner wall of the vacuum vessel of the Large Helical Device. They were made of stainless steel and were used for a CO_2 laser polarimeter. The reflectivity for a CO_2 laser beam dropped up to 40% after the start of glow discharge cleanings and main plasma experiments. Then it decreased gradually. The reflectivity in a wavelength range shorter than 10 ?m decreased significantly through one experimental campaign (about 4 months). On the other hand the reflectivity in a wavelength range longer than 50 ?m was larger than 70%. Decrease in the reflectivity in the central region of mirrors was more significant (the reflectivity for visible beams became almost zero) than that in the edge. The distribution of the reflectivity along the radial direction is expected to be related to the shape of the retroreflector. The parallelism of the reflected beam to an incident one also deteriorated. The changes in the polarization angle and in the ellipticity of reflected light polarization were not observed from the visible to the far infrared range