Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus ). In single cases, Mycoplasma bacteria, , fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.

Baker, S.J., Belcher, C.M., Barclay, R.S., Hesselbo, S.P., Laurin, J., Sageman, B.B., 2019. CO -induced climate 2 forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2. GSA Bulletin 132, 321- 333.

https://doi.org/10.1130/B35097.1 Cretaceous oceanic anoxic event 2 (OAE2) is thought to have been contemporary with extensive volcanism and the release of large quantities of volcanic CO capable of triggering marine anoxia through a series of 2 biogeochemical feedbacks. High-resolution reconstructions of atmospheric CO concentrations across the 2 initiation of OAE2 suggest that there were also two distinct pulses of CO drawdown coeval with increased 2 organic carbon burial. These fluctuations in CO likely led to significant climatic changes, including 2 fluctuations in temperatures and the hydrological cycle. Paleofire proxy records suggest that wildfire was a common occurrence throughout the Cretaceous Period, likely fueled by the estimated high atmospheric O 2 concentrations at this time. However, over geological time scales, the likelihood and behavior of fire are also controlled by other factors such as climate, implying that CO -driven climate changes should also be observable 2 in the fossil charcoal record. We tested this hypothesis and present a high-resolution study of fire history through the use of fossil charcoal abundances across the OAE2 onset, and we compared our records to the estimated CO fluctuations published 2 from the same study sites. Our study illustrates that inferred wildfire activity appears to relate to changes in CO 2 occurring across the onset of OAE2, where periods of CO drawdown may have enabled an increase in fire 2 activity through suppression of the hydrological cycle. Our study provides further insight into the relationships between rapid changes in the carbon cycle, climate, and wildfire activity, illustrating that CO and climate 2 changes related to inferred wildfire activity can be detected despite the estimated high Cretaceous atmospheric O concentrations. 2

Balfourier, A., Luciani, N., Wang, G., Lelong, G., Ersen, O., Khelfa, A., Alloyeau, D., Gazeau, F., Carn, F., 2020. Unexpected intracellular biodegradation and recrystallization of gold nanoparticles. Proceedings of the National Academy of Sciences 117, 103-113.

https://doi.org/10.1073/pnas.1911734116 Significance: While gold nanoparticles are at the core of an increasing range of medical applications, their fate in the organism has barely been studied so far. Because of their chemical inertness, common belief is that gold nanoparticles remain endlessly intact in tissues. We show that 4- to 22-nm gold nanoparticles are actually degraded in vitro by cells, with a faster degradation of the smallest size. Transcriptomics studies reveal the active role of cell lysosome into this biodissolution. Furthermore, we point out that the released gold recrystallizes into biopersistent nanostructures. Interestingly, these degradation products are similar to previously observed gold deposits in human tissues after gold salts treatment for rheumatoid arthritis, underlying a common metabolism between gold nanoparticles and ionic gold. Abstract: Gold nanoparticles are used in an expanding spectrum of biomedical applications. However, little is known about their long-term fate in the organism as it is generally admitted that the inertness of gold nanoparticles prevents their biodegradation. In this work, the biotransformations of gold nanoparticles captured by primary fibroblasts were monitored during up to 6 mo. The combination of electron microscopy imaging and transcriptomics study reveals an unexpected 2-step process of biotransformation. First, there is the degradation of gold nanoparticles, with faster disappearance of the smallest size. This degradation is mediated by NADPH oxidase that produces highly oxidizing reactive oxygen species in the lysosome combined with a cell-protective expression of the nuclear factor, erythroid 2. Second, a gold recrystallization process generates biomineralized nanostructures consisting of 2.5-nm crystalline particles self-assembled into nanoleaves. Metallothioneins are