The "unusual" reproduction of planktic foraminifera: an asexual reproductive phase of Neogloboquadrina pachyderma (Ehrenberg)

Abstrac

Ultrastructural observations on prokaryotic associates of benthic foraminifera : food, mutualistic symbionts, or parasites?

© The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Marine Micropaleontology 138 (2018): 33-45, doi:10.1016/j.marmicro.2017.09.001.Because prokaryotes (Eubacteria, Archaea) are ubiquitous in the marine realm, it may not be surprising that they are important to the diet of at least some foraminifera. Over recent decades, Transmission Electron Microscopy (TEM) has revealed that, at the ultrastructural level, additional intimate relationships exist between prokaryotes and foraminifera. For example, the cytoplasm of a variety of benthic foraminiferal species contains intact prokaryotes. Other benthic foraminiferal species support prokaryotic populations on their exterior. Some of these prokaryote-foraminifera associations are sufficiently consistent to be considered symbioses. Symbiotic relationships include beneficial associations (mutualism; commensalism) to detrimental associations (parasitism). Here, we provide a synopsis of known foraminiferal- prokaryotic symbioses and TEM micrographs illustrating many specific associations. We further comment on and illustrate additional interactions such as bacterial scavenging on foraminifera and foraminiferal feeding on prokaryotes. Documenting and understanding all of these microbial interactions will contribute to a more comprehensive knowledge of benthic marine ecology and biology.JMB’s contributions were funded by US NSF funding over many years, most recently NSF grant OCE-1634469, as well as the WHOI Robert W. Morse Chair for Excellence in Oceanography and The Investment in Science Fund at WHOI. MT and HN’s contributions were funded by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (no. 24340131 to MT and no. 22740340 to HN)

Construction and Superfunction of Metal-oxide Nanostructures and Interfaces(Interfaces by various techniques)

Metal oxides show such versatile properties as high T_C superconductivity, ferroelectricity, colossal magnetoresistance and non-linear optical properties. By developing laser molecular beam epitaxy, we have been working on atomic scale control for the heteroepitaxy of these materials in order to explore a novel field of "oxide electronics", in which monolithically integrated devices composed of epitaxially grown oxide nanostructures show outstanding performances that Si-based semiconducting devices would not be able to give. Among many topics we have, we concentrate on Josephson tunnel junction made out of high T_C superconductors and ultra-violet laser emission from ZnO nanocrystal films

Molecular characterization of bacteria and kleptoplast within Virgulinella fragilis

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In Search of a Sustainable Global Agri-Food System

The potential to meet global food demand fully exists through global development of the high-technology (HT), high-intensity type of agriculture and food processing system prevailing in developed countries. This system unfortunately is also responsible for much natural resource degradation, environmental damage and ecological imbalance. Meantime the Earth's human population continues to grow, placing ever-increasing demand on global natural resources, not only for food but also for living and recreational space. A more sustainable agri-food system must evolve. Sustainability is complex, and ought to be approached from a multidisciplinary perspective and compromise sought in resolving the obvious conflicts amongst biological, environmental, ecological, socio-economic, and other individual disciplines and competing philosophies. These form the basis for comparing three different agricultural production systems: high technology (HT); reduced input (RI), and organic (ORG). The three systems are compared empirically using primary data from farms in each group in southern Ontario, Canada. HT systems prevalent in Canada is highly productive, but its sustainability is questionable. It was concluded that the HT system should not be the model for the future. The ORG system is the least inimical to the environment, ecology, and human operators. It was concluded that the ORG system is sustainable except for its requirement for extensive use of land. The RI system causes minimal environmental and ecological damage. It is most profitable and is supportive of rural farm community viability. It was concluded that the RI system holds the best potential for meeting overall sustainability for the global agri-food system.Farm Management, Land Economics/Use,

Evaluation of atherosclerotic lesions using dextran- and mannan–dextran-coated USPIO: MRI analysis and pathological findings

Magnetic resonance imaging (MRI) can detect atherosclerotic lesions containing accumulations of ultrasmall superparamagnetic iron oxides (USPIO). Positing that improved USPIO with a higher affinity for atherosclerotic plaques would yield better plaque images, we performed MRI and histologic studies to compare the uptake of dextran- and mannan–dextran-coated USPIO (D-USPIO and DM-USPIO, respectively) by the atherosclerotic walls of rabbits. We intravenously injected atherosclerotic rabbits with DM-USPIO (n = 5) or D-USPIO (n = 5). Two rabbits were the controls. The doses delivered were 0.08 (dose 1) (n = 1), 0.4 (dose 2) (n = 1), or 0.8 (dose 3) (n = 3) mmol iron/Kg. The dose 3 rabbits underwent in vivo contrast-enhanced magnetic resonance angiography (MRA) before and 5 days after USPIO administration. Afterwards, all animals were euthanized, the aortae were removed and subjected to in vitro MRI study. The signal-to-noise ratio (SNR) of the aortic wall in the same region of interest (ROI) was calculated in both in vivo and in vitro studies. Histological assessment through measurement of iron-positive regions in Prussian blue-stained specimens showed that iron-positive regions were significantly larger in rabbits injected with DM- rather than D-USPIO (P < 0.05) for all doses. In vivo MRA showed that the SNR-reducing effect of DM- was greater than that of D-USPIO (P < 0.05). With in vitro MRI scans, SNR was significantly lower in rabbits treated with dose 2 of DM-USPIO compared with D-USPIO treatment (P < 0.05), and it tended to be lower at dose 3 (P < 0.1). In conclusion, we suggest that DM-USPIO is superior to D-USPIO for the study of atherosclerotic lesions in rabbits

16S rRNA Gene Metabarcoding Indicates Species-Characteristic Microbiomes in Deep-Sea Benthic Foraminifera

Foraminifera are unicellular eukaryotes that are an integral part of benthic fauna in many marine ecosystems, including the deep sea, with direct impacts on benthic biogeochemical cycles. In these systems, different foraminiferal species are known to have a distinct vertical distribution, i.e., microhabitat preference, which is tightly linked to the physico-chemical zonation of the sediment. Hence, foraminifera are well-adapted to thrive in various conditions, even under anoxia. However, despite the ecological and biogeochemical significance of foraminifera, their ecology remains poorly understood. This is especially true in terms of the composition and diversity of their microbiome, although foraminifera are known to harbor diverse endobionts, which may have a significant meaning to each species' survival strategy. In this study, we used 16S rRNA gene metabarcoding to investigate the microbiomes of five different deep-sea benthic foraminiferal species representing differing microhabitat preferences. The microbiomes of these species were compared intra- and inter-specifically, as well as with the surrounding sediment bacterial community. Our analysis indicated that each species was characterized with a distinct, statistically different microbiome that also differed from the surrounding sediment community in terms of diversity and dominant bacterial groups. We were also able to distinguish specific bacterial groups that seemed to be strongly associated with particular foraminiferal species, such as the family Marinilabiliaceae for Chilostomella ovoidea and the family Hyphomicrobiaceae for Bulimina subornata and Bulimina striata. The presence of bacterial groups that are tightly associated to a certain foraminiferal species implies that there may exist unique, potentially symbiotic relationships between foraminifera and bacteria that have been previously overlooked. Furthermore, the foraminifera contained chloroplast reads originating from different sources, likely reflecting trophic preferences and ecological characteristics of the different species. This study demonstrates the potential of 16S rRNA gene metabarcoding in resolving the microbiome composition and diversity of eukaryotic unicellular organisms, providing unique in situ insights into enigmatic deep-sea ecosystems.Peer reviewe