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Collaborative studies conducted during the period 2002-2017 between Polish and German scientists from two organisations on the geological structure of peat deposits, lignites, hard coals and bituminous shales of Germany, Poland and France and the petrology of coal are described. Topics discussed include Helmstedt lignite region; Posidonia bituminous-shale quarry (Swabian Jura); Messel bituminous-shale strip mine and fossil site ((Darmstadt); field session on peat bog, Svaty Sebestian mountain; Stephanian coal seam, Ronchamp coal basin (France); boghead coals and oil shales, Autun-Epinac coal basin; geological structure of Stephanian-Permian Autun-Epinac coal basin; lignite mine strips and dumps, Lower Rhine; and geological structure of Profen strip mine (Zeitz)., Collaborative studies conducted during the period 2002-2017 between Polish and German scientists from two organisations on the geological structure of peat deposits, lignites, hard coals and bituminous shales of Germany, Poland and France and the petrology of coal are described. Topics discussed include Helmstedt lignite region; Posidonia bituminous-shale quarry (Swabian Jura); Messel bituminous-shale strip mine and fossil site ((Darmstadt); field session on peat bog, Svaty Sebestian mountain; Stephanian coal seam, Ronchamp coal basin (France); boghead coals and oil shales, Autun-Epinac coal basin; geological structure of Stephanian-Permian Autun-Epinac coal basin; lignite mine strips and dumps, Lower Rhine; and geological structure of Profen strip mine (Zeitz).

Cell-to-cell communication is essential for the organization, coordination, and development of cellular networks and multi-cellular systems. Intercellular communication is mediated by soluble factors (including growth factors, neurotransmitters, and cytokines/chemokines), gap junctions, exosomes and recently described tunneling nanotubes (TNTs). It is unknown whether a combination of these communication mechanisms such as TNTs and gap junctions may be important, but further research is required. TNTs are long cytoplasmic bridges that enable long-range, directed communication between connected cells. The proposed functions of TNTs are diverse and not well understood but have been shown to include the cell-to-cell transfer of vesicles, organelles, electrical stimuli and small molecules. However, the exact role of TNTs and gap junctions for intercellular communication and their impact on disease is still uncertain and thus, the subject of much debate. The combined data from numerous laboratories indicate that some TNT mediate a long-range gap junctional communication to coordinate metabolism and signaling, in relation to infectious, genetic, metabolic, cancer, and age-related diseases. This review aims to describe the current knowledge, challenges and future perspectives to characterize and explore this new intercellular communication system and to design TNT-based therapeutic strategies.

Anthrax toxin comprises three soluble proteins: protective antigen (PA), lethal factor (LF), and edema factor (EF). PA must be cleaved by host proteases before it oligomerizes and forms a prepore, to which LF and EF bind. After endocytosis of this tripartite complex, the prepore transforms into a narrow transmembrane pore that delivers unfolded LF and EF into the host cytosol. Here, we find that translocation of multiple 90-kD LF molecules is rapid and efficient. To probe the molecular basis of this translocation, we calculated a three-dimensional map of the fully loaded (PA63)7-(LF)3 prepore complex by cryo-electron microscopy (cryo-EM). The map shows three LFs bound in a similar way to one another, via their N-terminal domains, to the surface of the PA heptamer. The model also reveals contacts between the N- and C-terminal domains of adjacent LF molecules. We propose that this molecular arrangement plays an important role in the maintenance of translocation efficiency through the narrow PA pore.

The actin-related protein 2/3 (Arp2/3) complex mediates the formation of branched actin filaments at the leading edge of motile cells and in the comet tails moving certain intracellular pathogens. Crystal structures of the Arp2/3 complex are available, but the architecture of the junction formed by the Arp2/3 complex at the base of the branch was not known. In this study, we use electron tomography to reconstruct the branch junction with sufficient resolution to show how the Arp2/3 complex interacts with the mother filament. Our analysis reveals conformational changes in both the mother filament and Arp2/3 complex upon branch formation. The Arp2 and Arp3 subunits reorganize into a dimer, providing a short-pitch template for elongation of the daughter filament. Two subunits of the mother filament undergo conformational changes that increase stability of the branch. These data provide a rationale for why branch formation requires cooperative interactions among the Arp2/3 complex, nucleation-promoting factors, an actin monomer, and the mother filament.

Contributions of actin-related proteins (Arp) 2 and 3 nucleotide state to Arp2/3 complex function were tested using nucleotide-binding pocket (NBP) mutants in Saccharomyces cerevisiae. ATP binding by Arp2 and Arp3 was required for full Arp2/3 complex nucleation activity in vitro. Analysis of actin dynamics and endocytosis in mutants demonstrated that nucleotide-bound Arp3 is particularly important for Arp2/3 complex function in vivo. Severity of endocytic defects did not correlate with effects on in vitro nucleation activity, suggesting that a critical Arp2/3 complex function during endocytosis may be structural rather than catalytic. A separate class of Arp2 and Arp3 NBP mutants suppressed phenotypes of mutants defective for actin nucleation. An Arp2 suppressor mutant increased Arp2/3 nucleation activity. Electron microscopy of Arp2/3 complex containing this Arp2 suppressor identified a structural change that also occurs upon Arp2/3 activation by nucleation promoting factors. These data demonstrate the importance of Arp2 and Arp3 nucleotide binding for nucleating activity, and Arp3 nucleotide binding for maintenance of cortical actin cytoskeleton cytoarchitecture.

Actin branch junctions are conserved cytoskeletal elements critical for the generation of protrusive force during actin polymerization-driven cellular motility. Assembly of actin branch junctions requires the Arp2/3 complex, upon activation, to initiate a new actin (daughter) filament branch from the side of an existing (mother) filament, leading to the formation of a dendritic actin network with the fast growing (barbed) ends facing the direction of movement. Using genetic labeling and electron microscopy, we have determined the structural organization of actin branch junctions assembled in vitro with 1-nm precision. We show here that the activators of the Arp2/3 complex, except cortactin, dissociate after branch formation. The Arp2/3 complex associates with the mother filament through a comprehensive network of interactions, with the long axis of the complex aligned nearly perpendicular to the mother filament. The actin-related proteins, Arp2 and Arp3, are positioned with their barbed ends facing the direction of daughter filament growth. This subunit map brings direct structural insights into the mechanism of assembly and mechanical stability of actin branch junctions.

The history of the development of crude oil underground mining in the oil field at Wietz, north of Hannover, Lower Saxony, Germany, which was operational in the years 1859-1963 and has been a museum of crude oil since 1970, is presented. The crude oil was exploited by the use of borehole and other mining methods such as shafts and galleries. There were 200 holes drilled in the deposit, located on the salt dome, with four out of five being productive. In the period 1918-1963, about 1 000 000 000 000 g of crude oil was produced from the main horizon of the deposit, the oil-bearing Wealden (Lower Cretaceous) sands. Methods of underground mining for crude oil exploitation including drainage of the deposit with galleries and exploitation of oil sands in a system of short walls are described. Methods of backfilling, transport of the material, preparation of rocks by thermal methods and crude oil recovery are discussed., The history of the development of crude oil underground mining in the oil field at Wietz, north of Hannover, Lower Saxony, Germany, which was operational in the years 1859-1963 and has been a museum of crude oil since 1970, is presented. The crude oil was exploited by the use of borehole and other mining methods such as shafts and galleries. There were 200 holes drilled in the deposit, located on the salt dome, with four out of five being productive. In the period 1918-1963, about 1 000 000 000 000 g of crude oil was produced from the main horizon of the deposit, the oil-bearing Wealden (Lower Cretaceous) sands. Methods of underground mining for crude oil exploitation including drainage of the deposit with galleries and exploitation of oil sands in a system of short walls are described. Methods of backfilling, transport of the material, preparation of rocks by thermal methods and crude oil recovery are discussed.