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Radionuclides produced by 20th-century human nuclear activities from 1945 (e.g., atmospheric nuclear explosions and nuclear-fuel reprocessing) made significant impacts on earth's surface environments. Long-lived shallow-water corals living in tropical/subtropical seas incorporate the anthropogenically-produced radionuclides, including 129 I and 14 C, into their skeletons, and provide time series records of the impacts of nuclear activities. Here, we present 129 I/ 127 I and Δ 14 C time series records of an annually-banded modern coral skeleton from Rowley Shoals, off the northwestern coast of Australia, in the far eastern Indian Ocean. The 129 I/ 127 I and Δ 14 C records, covering the period 1930s-1990s, exhibit distinct increases caused by the nuclear activities, and their increasing profiles are clearly different from each other. The first distinct 129 I/ 127 I increase occurs from 1955 to 1959, followed by a decrease in 1960-1963. The increase is probably due to US atmospheric nuclear explosions in Bikini and Eniwetok Atolls in 1954, 1956 and 1958. The 129 I produced in those nuclear tests would be transported by the North Equatorial Current, a portion of which passes through the Indonesian Throughflow and then reaches Rowley Shoals. This initial increase from 1955 is, however, absent in the Δ 14 C record, which shows a distinct increase from 1959 and its peak around the mid-1970s, followed by a gradual decrease. This absence and the 4-year-delayed Δ 14 C increase are likely due to dilution of explosion-produced 14 C with natural carbon (by seawater mixing and air-sea gas exchange) being much more intense than that of explosion-produced 129 I with natural iodine (by the same processes), suggesting that the 129 I/ 127 I ratio is a more conservative anthropogenic tracer in surface ocean waters, as compared to Δ 14 C. The second 129 I/ 127 I increase is contemporaneous with a rapid Δ 14 C increase during 1964-1967, followed by a rapid 129 I/ 127 I decrease in 1968-1969; the increases can be ascribed to very large atmospheric nuclear explosions conducted in the former Soviet Union in 1961-1962. The third 129 I/ 127 I increase appears between 1969/1970 and 1992, which can be attributed to airborne 129 I released from nuclear-fuel reprocessing facilities in Europe, the former Soviet Union and the US. The coral 129 I/ 127 I and Δ 14 C time series records, combined with previous studies, enhance our understanding of the behavior of anthropogenic 129 I and 14 C in the global ocean and atmosphere., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Rationale: Foodcrust, the charred deposit adhering to the surface of containers, is a possible source of information on the function of ancient vessels and the subsistence of prehistoric humans. While the carbon isotope ratios in those materials are useful in detecting the usage of C 4 plants, the reliability of nitrogen isotopic signatures has not been fully investigated., Methods: The validity of bulk nitrogen isotope ratios has previously been investigated in coastal or riverine environments, where multiple resources from terrestrial and aquatic ecosystems were available, but not in terrestrial settings which provide a simpler mixing of terrestrial animals and plants. Hence, we conducted an exhaustive study on charred deposits on potsherds at two inland archaeological sites belonging to prehistoric Jomon hunter-gathers in central Japan, focusing on δ 15 N values and atomic N/C ratios determined using an isotope ratio mass spectrometer and an elemental analyzer, respectively., Results: For both sites, the δ 15 N values showed significant correlations with the N/C ratios among samples from the inner surface, suggesting that these have recorded animal contribution. Furthermore, previous studies of Neolithic pottery from North Europe and Far East Russia bearing strong marine signatures had shown reasonably higher δ 15 N values and N/C ratios in comparison with our data from terrestrial settings. On the other hand, some charred materials probably originating from plant starch showed lower values with both parameters. Samples from the outer surface produced less meaningful isotopic and elemental ratios altered by a thermal effect and/or contamination from soot., Conclusions: When the samples of foodcrusts were selected carefully from the inner surface, bulk nitrogen isotopes and N/C ratios reflect the composition of what was cooked or processed in containers. This will provide useful information for understanding the human adaptation from the Late Pleistocene to the Holocene in conjunction with residual lipid analyses., (© 2019 John Wiley & Sons, Ltd.)

The European bumblebee, Bombus terrestris, is an invasive eusocial species whose distribution is expanding greatly beyond its native range because numerous colonies are imported to or locally produced in non-native countries for pollination of agricultural crops. Closely related species exist in Japan where the unrestricted import and use of B. terrestris has resulted in the establishment of wild colonies. Laboratory studies previously showed that B. terrestris and Japanese native species can copulate and produce fertilized eggs. Although these eggs do not hatch, the interspecific mating can cause a serious reproductive disturbance to native bumblebees. In this study, we determined the frequencies of interspecies mating between B. terrestris males and native bumblebee queens in the wild on the islands of Hokkaido and Honshu by analyzing the DNA sequences of spermatozoa stored in spermathecae of native queens. We found that 20.2% of B. hypocrita hypocrita queens and 30.2% of B. hypocrita sapporoensis queens had spermatozoa of B. terrestris males in their spermathecae. Given that a Bombus queen generally mates only once in her life, such high frequencies of interspecific mating with B. terrestris pose serious threats to the populations of native bumblebees in Japan.

The bumblebee Bombus terrestris is not only an effective pollinator, but also a potential invasive alien species outside its native range. Recently, nearly 30% of queens of the Japanese native species Bombus hypocrita sapporoensis and B. hypocrita hypocrita were estimated to copulate with B. terrestris males in the field, suggesting that indigenous bumblebees could be genetically deteriorated through hybrid production with the introduced species. In this study, we evaluated hybrid production between the introduced B. terrestris and the indigenous B. hypocrita sapporoensis under laboratory conditions. The hatching rate of eggs derived from interspecific matings was 0% and 8.6% depending on the direction of the cross, which was significantly lower than that from intraspecific matings of B. terrestris (76.9%) and B. hypocrita sapporoensis (78.9%). Genetic studies using microsatellite markers revealed that both haploid and diploid individuals were present in the egg stage, whereas all hatched larvae were haploid. In addition, histological studies revealed that eggs derived from interspecific matings terminated development 2 days after oviposition. These results strongly suggested that eggs derived from interspecific matings are inviable due to post-mating isolation mechanisms. Mass release of exotic pollinators could cause serious population declines of native bumblebee species.

Helicobacter pylori(H. pylori) is a causative agent for chronic gastritis and is an important risk factor for peptic ulcers, gastric carcinomas, and gastric MALT lymphomas. In 2000, the Japanese Society for Helicobacter Research published a guideline on the diagnosis and treatment of H. pylori infection for physicians in routine medical practice. In this guideline, H. pylori eradication therapy is recommended in gastric or duodenal ulcer patients. H. pylori eradication is also recommended in gastric MALT lymphoma patients but the guideline says it should be done at specialist institutions. Considering the high prevalence of gastric carcinomas in Japan. H. pylori eradication for the prevention of gastric carcinomas should be discussed urgently.