Temperature-induced radioresistance of Escherichia coli cells

A marked increase in radioresistance of E. coli cells, of the wild-type repair genotype, was observed when they were exposed to gamma-radiation at 40-45 degrees C. The effect of the thermoinduced radioresistance did not depend on the growth medium and the pre-incubation temperature but disappeared completely after treatment of cells by chloramphenicol or CaCl2 or after modification of cell membranes by exogenous cholesterol. This phenomenon was not observed with UV-irradiation. It is suggested that the thermoinduced radioresistance is connected with the activation of the membrane-associated repair complex.     

UV-mutable hybrids of Salmonella incorporating escherichia coli Region adjacent to Tryptophan operon

Summary Salmonella typhimurium recombinants have been constructed which have acquired UV-induced mutability. Such recombinants were obtained after transfer of plasmid F126 from E. coli. UV-mutability was acquired by UV-stable Salmonella as a nonselective marker after selection of trp ⁺ marker in 2.5% of the cases. Possible deficiency in UV-stable Salmonella of the umuC gene is discussed.     

Use of CR in the detection of present gastric cancer: diagnostic aspects

The authors describe the state-of-the-art of gastric cancer detection in detail and show the current principles of its radiodiagnosis. They provide a detailed explanation for that radiodiagnosis should be urgently returned into gastroenterology as an equal with endoscopy, which is based on the existing tendency for the major morphological types of gastric cancer to appear. The present-day capacities of radiodiagnosis of gastric cancer are mainly based on the introduction of the digital technologies into traditional radiology, which will replace the analog imaging principle in the foreseeable future. The authors present their data of examining 300 gastric cancer cases diagnosed by the CR system and later verified by a morphological study of resected gastric specimens. They emphasize that intraparietally growing gastric cancer is frequently inaccessible for endoscopy long, which determines the need for two basic procedures (radiodiagnosis and endoscopy) coexisting on a par for the detection of gastric cancer. They are sure that computed radiology (CR) will be the most acceptable way of changing traditional radiology to the digital imaging principle in primary, municipal health care in the near future.     

1-Phenylethynylpyrene (1-PEPy) as refined excimer forming alternative to pyrene: case of DNA major groove excimer

1-Phenylethynylpyrene fluorochrome was studied as meta- and para-derivatives of arabino-uridine-2'-carbamates in ss and dsDNA. 1-PEPy showed red-shifted emission and increased fluorescence quantum yield compared to pyrene. Although 1-PEPy has very short excited lifetime (<2.5 ns), it is able to form inter- and intrastrand excimers on DNA, probably resulting from spatial preorganization of two dye molecules.     

Retraction Statement: Comparison of nitrogen inputs and accumulation in 210Pb‐dated peat cores: Evidence for biological N2‐fixation in Central European peatlands despite decades of atmospheric N pollution

“Comparison of nitrogen inputs and accumulation in ²¹⁰Pb‐dated peat cores: Evidence for biological N₂‐fixation in Central European peatlands despite decades of atmospheric N pollution” https://doi.org/10.1111/gcb.14505 , by Martin Novak, Melanie A. Vile, Jan Curik, Bohuslava Cejkova, Jiri Barta, Marketa Stepanova, Ivana Jackova, Frantisek Buzek, Leona Bohdalkova, Eva Prechova, Frantisek Veselovsky, Marie Adamova, Ivana Valkova and Arnost Komarek. The above article, first published online in Wiley Online Library (wileyonlinelibrary.com) in Global Change Biology, has been retracted by agreement between the authors, the journal Editor‐in‐Chief, Stephen P. Long, and John Wiley & Sons Ltd. Since publication of the above article, it was brought to the attention of the authors that the peat accretion rates violate reasonable ranges of peatland C/N/P stoichiometry, placing the quantitative conclusions of the article in serious error. The authors apologize for any inconvenience the publication of this work may have caused our readers. REFERENCE Novak, M., Vile, M. A., Cejkova, B., Barta, J., Stepanova, M., Jackova, I., Buzek, F., Bohdalkova, L., Prechova, E., Veselovsky, F., Adamova, M., Valkova, I., & Komarek, A. (2018). Comparison of nitrogen inputs and accumulation in ²¹⁰Pb‐dated peat cores: Evidence for biological N₂‐fixation in Central European peatlands despite decades of atmospheric N pollution. Global Change Biology.. https://doi.org/10.1111/gcb.14505     

The Arabidopsis YUCCA1 flavin monooxygenase functions in the indole-3-pyruvic acid branch of auxin biosynthesis

The effects of auxins on plant growth and development have been known for more than 100 years, yet our understanding of how plants synthesize this essential plant hormone is still fragmentary at best. Gene loss- and gain-of-function studies have conclusively implicated three gene families, CYTOCHROME P450 79B2/B3 (CYP79B2/B3), YUCCA (YUC), and TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1/TRYPTOPHAN AMINOTRANSFERASE-RELATED (TAA1/TAR), in the production of this hormone in the reference plant Arabidopsis thaliana. Each of these three gene families is believed to represent independent routes of auxin biosynthesis. Using a combination of pharmacological, genetic, and biochemical approaches, we examined the possible relationships between the auxin biosynthetic pathways defined by these three gene families. Our findings clearly indicate that TAA1/TARs and YUCs function in a common linear biosynthetic pathway that is genetically distinct from the CYP79B2/B3 route. In the redefined TAA1-YUC auxin biosynthetic pathway, TAA1/TARs are required for the production of indole-3-pyruvic acid (IPyA) from Trp, whereas YUCs are likely to function downstream. These results, together with the extensive genetic analysis of four pyruvate decarboxylases, the putative downstream components of the TAA1 pathway, strongly suggest that the enzymatic reactions involved in indole-3-acetic acid (IAA) production via IPyA are different than those previously postulated, and a new and testable model for how IAA is produced in plants is needed.     

Vivid molecular divergence over volcanic remnants: the phylogeography of Megadromus guerinii on Banks Peninsula,New Zealand

Megadromus guerinii, an endemic carabid beetle (Carabidae), is the most common carabid throughout its restricted range on Banks Peninsula, a formation of extinct volcanoes in Canterbury, New Zealand. This study characterises the small-scale phylogeographic patterns of M. guerinii across the formerly volcanically active Banks Peninsula using mitochondrial and ribosomal genes. Between the eastern and western areas of the peninsula, the mitochondrial, but not nuclear, DNA has a well-defined geographic distribution. Specifically, mitochondrial cytochrome c oxidase subunit I (CO1) identifies two distinct groups (> 6% divergence between eastern and western beetles) while ribosomal genes show no discernible pattern. Whether such a pattern represents male-biased dispersal, Wolbachia infection, a recent range expansion of a divergent lineage, or a deeper historic separation is explored. There is potential that male-biased dispersal could have occurred. Wolbachia infection was not detected. We conclude that historical processes have likely separated taxa in the eastern and western peninsula.