Trace elements in rock salt and their bioavailability estimated from solubility in acid

In this study, 18 partly commercially available samples of rock salt from Austria, Germany, Pakistan, Poland, Switzerland, and Ukraine were investigated with respect to their content of trace elements using instrumental neutron activation analysis. Elements detected were Al, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, La, Mn, Na, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, and Zn, some of them only in individual cases. An estimation of the bioavailability of these trace elements was performed by dissolving an equivalent of the sodium chloride samples in diluted hydrochloric acid (simulating stomach acid), filtering off the insoluble components, and analyzing the evaporated filtrate. It could be shown that in most cases bioactive trace elements like Fe can be found in rock salt in the form of almost insoluble compounds and are therefore not significantly bioavailable, whereas thorium, for example, was partly bioavailable in two cases. A significant contribution to the recommended daily intake of metal trace elements by using rock salt for nutrition can be excluded.     

Growth responses of tropical forage plant species to vesicular-arbuscular mycorrhizae

Summary Growth and mineral uptake of twenty-four tropical forage legumes and grasses were compared under glasshouse conditions in a sterile low P oxisol, one part inoculated and the other not inoculated with mycorrhizal fungi. Shoot and root dry weights and total uptake of P, N, K, Ca, and Mg of all the test plants were significantly increased by mycorrhizal inoculation. Mycorrhizal inoculation, with few exceptions, decreased the root/shoot ratio. Non-mycorrhizal plants contained always lower quantities of mineral elements than mycorrhizal plants. Plant species showed differences in percentage mycorrhizal root length and there was no correlation between percentage mycorrhizal infection and plant growth parameters. A great variation in dependence on mycorrhiza was observed among forage species. Total uptake of all elements by non-mycorrhizal legumes and uptake of P, N and K by non-mycorrhizal grasses correlated inversely with mycorrhizal dependency. Mycorrhizal plants of all species used significantly greater quantities of soil P than the nonmycorrhizal plants. Utilization of soil P by non-mycorrhizal plants was correlated inversely with mycorrhizal dependency.     

Experimental confirmation of external fertilisation in the southern temperate rock lobster Jasus edwardsii (Hutton) (Decapoda: Palinuridae)

An experimental approach was adopted to clarify whether fertilisation in Jasus, a southern temperate genus of rock or spiny lobster (Decapoda: Palinuridae), occurs internally or externally. Female Jasus edwardsii, isolated from males until they moulted, to ensure that they were unmated, were randomly assigned to treatments in which internal fertilisation was physically prevented or to methodological controls. Examination of eggs attached to setae on the pleopods indicated that those from all females from all treatments had divided and were therefore fertilised. The only mechanism that explains these results is external fertilisation via a spermatophore deposited on the sternal plates of the female during copulation. Because of similar morphologies it is likely that in all Jasus species fertilisation occurs by this external mechanism. These experimental results are important in understanding the mating system of Jasus and in clarifying the phylogenetic relationships of this genus, and suggest that claims for internal fertilisation in related taxonomic groups warrant similar experimental testing before they are accepted.     

Archéologie de l’art rupestre au Mato Grosso (Brésil) : la Chapada dos Guimarães

As part of the research program “Archaeology of rock art in Mato Grosso: the Chapada dos Guimarães National Park (Cuiabá, Brazil)” placed under the coordination of Patrick Paillet and Veronica Wesolowski, an integrated and interdisciplinary approach to the territory still largely unpublished rock art of the Chapada dos Guimarães, has been undertaken since 2020 by combining strictly archaeological research (surveys, excavations and prospecting-inventories), rock art studies (analysis and graphic, photographic and photogrammetric recording of representations) and geological analyzes and, to define and characterize the structure of its ornamented landscapes. Our program is an extension of other projects carried out from 1983 to 2013 under the direction of Agueda Vilhena-Vialou, Denis Vialou and Levy Figuti in the region of the Cidade de Pedra near Rondonópolis and at Santa Elina in the Serra das Araras (Jangada). The region of the Chapada dos Guimarães National Park (PNCG) was the subject of exploration and partial studies between 2017 and 2019 under the direction of Caroline Bachelet within the framework of the program “Prehistory and Paleoenvironments in the Pantanal region (Mato Grosso, Brazil)”. The pursuit of archaeological research in the PNCG contributes to better defining the chronology and the dynamics of occupations at local and regional scales, to characterizing chrono-culturally the settlements and their variability in the region, extending from the Rio Vermelho in the south to the Rio Cuiabá in the north, and to understand the processes of settlement and/or mobility of past populations along the firm lands and especially the hydrographic systems that border the floodplains of the Pantanal and which constitute the main routes of population movement.     

Growth on Geological Time Scales in the Antarctic Cryptoendolithic Microbial Community

In the process of biogenous weathering of Beacon sandstone in the McMurdo Dry Valleys (Ross Desert), Antarctica, periods of microbial growth, on the time scale of 103-104 years, alternate with sudden exfoliation events. The present study addressed the question of whether microbial growth is continuous between exfoliation events or whether each exfoliation is followed by a period of comparatively rapid growth and then an extended period of steady state. The color intensity (Munsell lightness value) of the rock surface is an indicator of relative age of the crust within the exfoliation cycle, permitting measurement of changes in microbial biomass on a geological time scale. Results indicate that microbial growth is continuous and that exfoliation occurs when the microbial biomass reaches the carrying capacity of the cryptoendolithic habitat.     

L’Art rupestre d’Alta,Norvège. Art et conscience

Located in northern Scandinavia, rock art sites from Alta are the silent witness of ancient people. Considering landscape, surfaces and engravings gives the opportunity to understand the relation of pictures to their context. Simultaneous understanding of both rock surface and picture offer to reach a graphical discourse. On the other hand mythology gives a new perspective to engravings and integrates them into a global values’ system. Power over representation and the rise of sacred feeling produce by those engravings create a special space closer to a higher reality. In that more than natural space respect to precise rules is of the first importance. By a metaphysic's knowledge, the shaman insures good fortune and well-being to the entire group. This paper offers to consider those different aspects and to shed light on their importance.     

Rock2 promotes the invasion and metastasis of hepatocellular carcinoma by modifying MMP2 ubiquitination and degradation

Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is a downstream effector of Rho that plays an important role in the tumorigenesis and progression of hepatocellular carcinoma (HCC). Matrix metalloproteinase 2 (MMP2) is a master regulator of tumor metastasis. In this study, we investigated the collections of Rock2 and MMP2 in HCCs and determined the potential role and molecular mechanism of Rock2 in MMP2-mediated invasiveness and metastasis. We found that Rock2 and MMP2 were markedly overexpressed in HCCs compared with the corresponding adjacent tissues, where a positive correlation in their expression was found. The knockdown of Rock2 significantly decreased MMP2 expression and inhibited the invasion and metastasis of HCC in vitro and in vivo. Additionally, the upregulation of MMP2 rescued the decreased migration and invasion induced by the knockdown of Rock2, whereas the knockdown of MMP2 decreased Rock2-enhanced HCC migration and invasion. Mechanistically, Rock2 stabilized MMP2 by preventing its ubiquitination and degradation. Together, our results link two drivers of invasion and metastasis in HCC and identify a novel pathway for MMP2 control.     

Patines et cortex de météorisation de grès du site rupestre d’Oum La Leg (Anti-Atlas, Maroc)

Within the framework of the European Commission's program “Patine du Desert” (DG Research; INCO-CT-FP6-2004-509100), partially concerning the preservation of Saharan engraved rock art, the approach led to the study of the sandstone patina from the rock art site of Oum La Leg (Anti-Atlas, Morocco). The rock and its Tazina school engravings are sometimes covered with a thin brown-ochre coating which only shows a dark patina, the desert patina. This film corresponds to a weathering cortex whose formation is contemporary with wet events from the Holocene period. On the surface, the patinas’ diversity is linked to the heterogeneous distribution of manganese oxides (birnessite and todorokite) due to a reorganisation which led to the incorporation of aeolian silts. Some dating suggestions are made to establish an ante quem age for the engraved lines.     

Local structuring factors of invertebrate communities in ephemeral freshwater rock pools and the influence of more permanent water bodies in the region

We used three isolated clusters of small ephemeral rock pools on a sandstone flat in Utah to test the importance of local structuring processes on aquatic invertebrate communities. In the three clusters we characterized all ephemeral rock pools (total: 27) for their morphometry, and monitored their water quality, hydrology and community assemblage during a full hydrocycle. In each cluster we also sampled a set of more permanent interconnected freshwater systems positioned in a wash, draining the water from each cluster of rock pools. This design allowed additional testing for the potential role of more permanent water bodies in the region as source populations for the active dispersers and the effect on the community structure in the rock pools. Species richness and community composition in the rock pools correlated with level of permanence and the ammonia concentration. The length of the rock pool inundation cycle shaped community structure, most probably by inhibiting colonization by some taxa (e.g. tadpoles and insect larvae) through developmental constraints. The gradient in ammonia concentrations probably reflects differences in primary production. The more permanent water bodies in each wash differed both environmentally and in community composition from the connected set of rock pools. A limited set of active dispersers was observed in the rock pools. Our findings indicate that aquatic invertebrate communities in the ephemeral rock pools are mainly structured through habitat permanence, possibly linked with biotic interactions and primary production. Handling editor: S. I. Dodson