Succession of soil algae on dumps from strip coal-mining in the Most region (Czechoslovakia)

In the years 1985–1986, the primary succession of algae on dumps from brown coal mining was studied in the Most region (North Bohemia, Czechoslovakia). The colonization of sterile clayic substrates by algae (several coccal species of chlorophytes and heteroconts) and mosses (protonemata) starts before the first ecesis of higher plants (in deposits about 3 months old). Diatoms and, later, cyanophytes accompany the algal community after 1 year. Filamentous types of heteroconts and green algae occur first on 7 year old dumps. Green algae represent the commonest group throughout the succession. The number of species continuously increases with the age of the dumps and finally reaches about 40 species from the 18th to 30th year. The species composition is similar to that in grassland biotopes in Czechoslovakia.     

Agrobacterium tumefaciens divisome proteins regulate the transition from polar growth to cell division

The mechanisms that restrict peptidoglycan biosynthesis to the pole during elongation and re‐direct peptidoglycan biosynthesis to mid‐cell during cell division in polar‐growing Alphaproteobacteria are largely unknown. Here, we explore the role of early division proteins of Agrobacterium tumefaciens including three FtsZ homologs, FtsA and FtsW in the transition from polar growth to mid‐cell growth and ultimately cell division. Although two of the three FtsZ homologs localize to mid‐cell, exhibit GTPase activity and form co‐polymers, only one, FtsZ_AT, is required for cell division. We find that FtsZ_AT is required not only for constriction and cell separation, but also for initiation of peptidoglycan synthesis at mid‐cell and cessation of polar peptidoglycan biosynthesis. Depletion of FtsZ_AT in A. tumefaciens causes a striking phenotype: cells are extensively branched and accumulate growth active poles through tip splitting events. When cell division is blocked at a later stage by depletion of FtsA or FtsW, polar growth is terminated and ectopic growth poles emerge from mid‐cell. Overall, this work suggests that A. tumefaciens FtsZ makes distinct contributions to the regulation of polar growth and cell division.     

Response to vocal music in Angelman syndrome contrasts with Prader-Willi syndrome

Parent-offspring conflict—conflict over resource distribution within families due to differences in genetic relatedness—is the biological foundation for many psychological phenomena. In genomic imprinting disorders, parent-specific genetic expression is altered, causing imbalances in behaviors influenced by parental investment. We use this natural experiment to test the theory that parent-offspring conflict contributed to the evolution of vocal music by moderating infant demands for parental attention. Individuals with Prader-Willi syndrome, a genomic imprinting disorder resulting from increased relative maternal genetic contribution, show enhanced relaxation responses to song, consistent with reduced demand for parental investment (Mehr, Kotler, Howard, Haig, & Krasnow, 2017, Psychological Science). We report the necessary complementary pattern here: individuals with Angelman syndrome, a genomic imprinting disorder resulting from increased relative paternal genetic contribution, demonstrate a relatively reduced relaxation response to song, suggesting increased demand for parental attention. These results support the extension of genetic conflict theories to psychological resources like parental attention.     

Conquest of the deep,old and cold: an exceptional limpet radiation in Lake Baikal

Lake Baikal is the deepest, oldest and most speciose ancient lake in the world. The lake is characterized by high levels of molluscan species richness and endemicity, including the limpet family Acroloxidae with 25 endemic species. Members of this group generally inhabit the littoral zone, but have been recently found in the abyssal zone at hydrothermal vents and oil-seeps. Here, we use mitochondrial and nuclear data to provide a first molecular phylogeny of the Lake Baikal limpet radiation, and to date the beginning of intra-lacustrine diversification. Divergence time estimates suggest a considerably younger age for the species flock compared with lake age estimates, and the beginning of extensive diversification is possibly related to rapid deepening and cooling during rifting. Phylogenetic relationships and divergence time estimates do not clearly indicate when exactly the abyssal was colonized but suggest a timeframe coincident with the formation of the abyssal in the northern basin (Middle to Late Pleistocene).     

Do not neglect surroundings in restoration of disturbed sites

We examined the influence of surroundings, i.e. proximity effects, on the course of spontaneous vegetation succession using two data sets. In the first data set, we tested the effects of surrounding vegetation (woodlands, wetlands, grasslands, and synanthropic) on succession in various disturbed habitats in the Czech Republic by comparing successional sites with more natural vegetation within 100 m and at 1 km from each site. The habitats included old fields, gravel‐sand pits, spoil heaps from black coal mining, industrially extracted peatlands, and acidic stone quarries. We found that, with the exception of wetlands, the influence of the vegetation types on seral vegetation was nearly always significant using marginal and partial Canonical Correspondence Analyses. In the second data set, which included 27 limestone quarries, we compared species lists outside (up to 100 m apart) and inside the quarries using Detrended Correspondence Analysis and the Sørensen similarity index. We found much higher species similarity between outside and inside particular limestone quarries than among the quarries themselves and among their surroundings, which also indicates that the seral vegetation is decisively influenced by the surroundings. We argue that restoration ecologists should carefully consider the nature of the surroundings of disturbed sites because of its profound impact on restoration processes. They should conduct inventories and prescribe some restoration measures not only inside a restored site, but also in its surroundings.     

Genotoxicity of 7H-dibenzo[c,g]carbazole and its methyl derivatives in human keratinocytes

Differences between tissues in the expression of drug-metabolizing enzymes may substantially contribute to tissue-specificity of chemical carcinogens. To verify this hypothesis, the spontaneously immortalized human keratinocytes HaCaT were used, in order to evaluate the genotoxic potential of 7H-dibenzo[c,g]carbazole (DBC), a known hepatocarcinogen and sarcomagen, and its synthetic tissue-specific derivatives, 5,9-dimethyl-DBC (DiMeDBC) and N-methyl-DBC (N-MeDBC), which manifest specific tropism to the liver and skin, respectively. HaCaT cells mainly express cytochrome P4501A1 (CYP1A1), which is involved in metabolism of DBC and N-MeDBC, but not DiMeDBC [10]. Both DBC and the sarcomagen N-MeDBC induced significant levels of DNA strand-breaks, micronuclei, and DNA adducts followed by the phosphorylation of the p53 protein and histone H2AX in HaCaT cells. In contrast, the specific hepatocarcinogen DiMeDBC was devoid of any significant genotoxic activity in this cell line. Our study demonstrates that the absence of drug-metabolizing enzyme(s) involved in DiMeDBC metabolism may contribute substantially to the tissue-specific genotoxicity of this hepatocarcinogen.     

Novel high-affinity binders of human interferon gamma derived from albumin-binding domain of protein G

Recombinant ligands derived from small protein scaffolds show promise as robust research and diagnostic reagents and next generation protein therapeutics. Here, we derived high-affinity binders of human interferon gamma (hIFNγ) from the three helix bundle scaffold of the albumin-binding domain (ABD) of protein G from Streptococcus G148. Computational interaction energy mapping, solvent accessibility assessment, and in silico alanine scanning identified 11 residues from the albumin-binding surface of ABD as suitable for randomization. A corresponding combinatorial ABD scaffold library was synthesized and screened for hIFNγ binders using in vitro ribosome display selection, to yield recombinant ligands that exhibited K(d) values for hIFNγ from 0.2 to 10 nM. Molecular modeling, computational docking onto hIFNγ, and in vitro competition for hIFNγ binding revealed that four of the best ABD-derived ligands shared a common binding surface on hIFNγ, which differed from the site of human IFNγ receptor 1 binding. Thus, these hIFNγ ligands provide a proof of concept for design of novel recombinant binding proteins derived from the ABD scaffold.     

Screening for microbial markers in Miocene sediment exposed during open-cast brown coal mining

Viable microorganisms were found in Miocene lacustrine clays of the cypris formation excavated from 200-m below the surface as spoil during open-cast brown coal mining (Sokolov Brown Coal Basin, North-Western Bohemia, Czech Republic). Both saprotrophic microfungi of the genera Penicillium, Verticillium, Cladosporium and Aspergillus as well as heterotrophic bacteria were isolated from an intact sediment cores. Heterotrophic bacteria were classified by the MIS Sherlock System as representatives of genera Nocardiopsis, Arthrobacter, Micrococcus, Kocuria, Rothia, Clavibacter, Bacillus, Paenibacillus, Brevibacillus, Microbacterium, Acinetobacter and Pseudomonas. A bacterium found among the strains had an atypical fatty acids profile enriched by branched fatty acids and polyunsaturated fatty acid (18:36) and gave no MIS Sherlock match. Phospholipid fatty acids analysis indicates a relatively high (535 pmol g⁻¹) but inhomogeneously distributed viable microbial biomass. Fatty acids analyses of non-fractioned lipids (representing viable, storage and dead biomass; 8390  pmol  g⁻¹) detected rich and homogenous profiles with fungal, bacterial and actinomycetal markers but no protozoan and algal fatty acids markers.     

Localization of multidrug transporter substrates within model membranes

Active extrusion of drugs from the cell interior by primary and secondary efflux pumps is an essential mechanism underlying the phenomenon of multidrug resistance. The first discovered and best characterized primary efflux pump found in humans is the ABC transporter P-glycoprotein (PGP), which shows very broad substrate specificity. Many of these molecules are lipophilic, and binding most likely takes place within the membrane. PGP could either translocate them from the inner to the outer leaflet (flippase) or extrude them from the membrane into the extracellular environment (hydrophobic vacuum cleaner). Recognition and binding of such a diverse set of substrates must be associated with a preferred membrane location, determined by molecular properties and lipid interactions. Therefore, a systematic study of the interaction among seven PGP substrates (phenazine, doxorubicin, cephalexin, ampicillin, chloramphenicol, penicillin G, and quercetin) and two modulators (quinidine and nicardipine) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) model membranes is reported here. The location profile of these molecules across the membrane was determined by (1)H NOESY MAS NMR based on (1)H-(1)H cross-peaks between their aromatic fingerprint region and lipid resonances. Although structurally rather diverse, all tested substances are found to have their highest concentration between the phosphate of the lipid headgroup and the upper segments of the lipid hydrocarbon chains. Our findings are consistent with PGP substrate and modulator binding from the membrane interface region.     

SL1 RNA gene recovery from Enterobius vermicularis ancient DNA in pre-Columbian human coprolites

Enterobius vermicularis, pinworm, is one of the most common helminths worldwide, infecting nearly a billion people at all socio-economic levels. In prehistoric populations the paleoparasitological findings show a pinworm homogeneous distribution among hunter-gatherers in North America, intensified with the advent of agriculture. This same increase also occurred in the transition from nomad hunter-gatherers to sedentary farmers in South America, although E. vermicularis infection encompasses only the ancient Andean peoples, with no record among the pre-Colombian populations in the South American lowlands. However, the outline of pinworm paleoepidemiology has been supported by microscopic finding of eggs recovered from coprolites. Since molecular techniques are precise and sensitive in detecting pathogen ancient DNA (aDNA), and also could provide insights into the parasite evolutionary history, in this work we have performed a molecular paleoparasitological study of E. vermicularis. aDNA was recovered and pinworm 5S rRNA spacer sequences were determined from pre-Columbian coprolites (4110 BC-AD 900) from four different North and South American archaeological sites. The sequence analysis confirmed E. vermicularis identity and revealed a similarity among ancient and modern sequences. Moreover, polymorphisms were identified at the relative positions 160, 173 and 180, in independent coprolite samples from Tulán, San Pedro de Atacama, Chile (1080-950 BC). We also verified the presence of peculiarities (Splicing leader (SL1) RNA sequence, spliced donor site, the Sm antigen biding site, and RNA secondary structure) which characterise the SL1 RNA gene. The analysis shows that the SL1 RNA gene of contemporary pinworms was present in pre-Columbian E. vermicularis by 6110 years ago. We were successful in detecting E. vermicularis aDNA even in coprolites without direct microscopic evidence of the eggs, improving the diagnosis of helminth infections in the past and further pinworm paleoepidemiological studies.