Refine
Year of publication
- 2021 (128) (remove)
Document Type
- Article (128) (remove)
Is part of the Bibliography
- yes (128)
Keywords
- Arabidopsis thaliana (4)
- evolution (4)
- conservation (3)
- dispersal (3)
- machine learning (3)
- mechanobiology (3)
- starch metabolism (3)
- Bombina bombina (2)
- Dictyostelium (2)
- Genomics (2)
- HIREC (2)
- LCSM (2)
- Lepus europaeus (2)
- Microcystis (2)
- Network clustering (2)
- SEIRA spectroelectrochemistry (2)
- SEPE (2)
- agricultural landscapes (2)
- anthropogenic environment (2)
- arable weeds (2)
- centrosome (2)
- cereal leaf beetle (2)
- connectivity (2)
- endozoochory (2)
- functional diversity (2)
- fungal pathogens (2)
- herbivory (2)
- interactions (2)
- iron-sulfur clusters (2)
- lake monitoring (2)
- metabolism (2)
- microplastics (2)
- microtubule-organization (2)
- mobile links (2)
- natural products (2)
- nutrient (2)
- population dynamics (2)
- protein-protein (2)
- range dynamics (2)
- resource competition (2)
- rodents (2)
- sedimentary ancient DNA (2)
- seed dispersal (2)
- seed dispersal syndrome (2)
- starch granule initiation (2)
- starch granules (2)
- starch morphology (2)
- structural equation model (2)
- stunting (2)
- urbanization (2)
- wheat (2)
- (SEPE) factors (1)
- A-type carrier protein (1)
- Agricultural landscapes (1)
- Amino acids (1)
- Analytical limitations (1)
- Anthropocene (1)
- Antibiotic resistance (1)
- Aphanizomenon (1)
- Aphis fabae (1)
- Apodemus agrarius (1)
- Asteraceae (1)
- B cell activation (1)
- Bacteria identification (1)
- Baetis (1)
- Beliefs and motivation (1)
- Bioconversion (1)
- Biology teachers (1)
- Biomimetic sensors (1)
- Body composition (1)
- Brachionus calyciflorus (1)
- Brachionus fernandoi (1)
- Buchnera (1)
- Burkina Faso (1)
- CNS (1)
- COVID-19 (1)
- CPI1 (1)
- Caenorhabditis elegans (1)
- Catecholamines (1)
- Cattle (1)
- Cep192 (1)
- Chew Bahir (1)
- Chlamydomonas (1)
- Chronodisruption (1)
- Classroom practices (1)
- Cloeon (1)
- Cographs (1)
- Coherent partition (1)
- Compound-specific stable isotope analysis (1)
- Conservation (1)
- Cost of resistance (1)
- Curculionidae (1)
- Cyanobium (1)
- Cytochrome b (1)
- Damage assessment (1)
- Danio rerio (zebrafish) (1)
- Diagnostic (1)
- Dispersal (1)
- Disturbance (1)
- Disturbance impacts (1)
- Docosahexaenoic acid (1)
- Domestic animals (1)
- Ecological changes (1)
- Ecological niche modeling (1)
- Etmopterus joungi (1)
- Etmopterus pusillus (1)
- FNR (1)
- Fatty acid conversion (1)
- Feeding behavior (1)
- Fis (1)
- Flexible sampling strategy (1)
- Floral induction (1)
- Flowering time (1)
- Forage values (1)
- Forest dependency (1)
- Fragmentation (1)
- Fresh water fish (1)
- FtsZ (1)
- FtsZ ring formation (1)
- Functional scaffolds (1)
- Genome-wide (1)
- Genomic selection (1)
- Graph (1)
- Graph partitions (1)
- Habitat loss (1)
- Habrophlebiodes (1)
- Hamiltonella (1)
- Haplogroups (1)
- Hippo signaling (1)
- Holocene (1)
- Host-symbiont interaction (1)
- Hybridoma technology (1)
- ICDP (1)
- In vitro immunization (1)
- Individual-based models (1)
- Infection (1)
- Ion mobility (1)
- Island biogeography (1)
- Kettle holes (1)
- Kucukcekmece Lagoon (1)
- LMA (1)
- Lake Bolshoe Toko (1)
- Landscape (1)
- Late Holocene (1)
- Life-history traits (1)
- Livestock (1)
- Long-distance seed dispersal (1)
- MIP (1)
- MTOC (1)
- Matrix vegetation (1)
- MbtH (1)
- Mcy gene (1)
- Melainabacteria (1)
- Metabolic models (1)
- Metabolic syndrome (1)
- Metabolites (1)
- Metacommunity dynamics (1)
- Metapopulation dynamics (1)
- Method (1)
- Methylheptadecanes (1)
- Microcystin (1)
- Mitochondria (1)
- MoaA (1)
- Moco biosynthesis (1)
- Molecularly Imprinted Polymers (1)
- Molecularly imprinted polymer (1)
- Monoclonal antibody (1)
- Morphology (1)
- NGS (1)
- Neolithic period (1)
- Neonatal chick (1)
- Neuropeptide Y (1)
- Nitrogen (1)
- Oil Palm (1)
- Organization model (1)
- PISA (1)
- Pastoralism (1)
- Patch isolation (1)
- Phalacridae (1)
- Phylogenetics (1)
- Phylogeny (1)
- Planktothrix (1)
- Plastibodies (1)
- Pollinator (1)
- Prime graphs (1)
- Protein complexes (1)
- Protein-bound microcystin (1)
- Protein-protein interaction (1)
- Proteins (1)
- RAFT dispersion polymerization (1)
- RNA-Seq (1)
- Reproductive phase (1)
- RpoS (1)
- RubisCO (1)
- SPD-2 (1)
- Secondary school (1)
- Seed dispersal by wind (1)
- Sericytochromatia (1)
- Shift work (1)
- Silene vulgaris (1)
- Simple Sequence Repeat (1)
- Single nucleotide polymorphisms (1)
- Single-nucleotide polymorphisms (1)
- Sleep quality (1)
- Snowella (1)
- Social-Economic-Political-Emotional (SEPE) factors (1)
- Species comparison (1)
- Species delimitation (1)
- Stability (1)
- Starch (1)
- Starch metabolism (1)
- Starch structure (1)
- Symbiosis (1)
- Synchronization (1)
- TMAO-reductase (1)
- TOR signaling (1)
- TTR (1)
- Taxonomy (1)
- Tree allometry (1)
- Tree growth classes (1)
- Trophic upgrading (1)
- Turing instability (1)
- TusA (1)
- Varves (1)
- Vegetative phase (1)
- Viruses (1)
- Volatile organic compounds (VOC) (1)
- Weevil (1)
- Whole-genome sequencing (1)
- Woody (1)
- Yap1/Wwtr1 (Taz) (1)
- a domain (1)
- aboveground biomass (1)
- acclimation (1)
- acid invertase (1)
- adaptation (1)
- adaptive introgression (1)
- admixture (1)
- agrin (1)
- alpha-glucan (1)
- alternative splicing (1)
- ambient temperature (1)
- amino acid (1)
- amplicon sequencing (1)
- anatomy (1)
- ancestral state reconstruction (1)
- angiogenesis (1)
- animal cognition (1)
- animal personality (1)
- animal pests (1)
- antibody producing cell selection (1)
- archival DNA (1)
- assembly (1)
- association studies (1)
- auxin (1)
- auxin biosynthesis (1)
- bats (1)
- behavior classification (1)
- behaviour (1)
- binding (1)
- biomass-trait feedback (1)
- biophysics (1)
- biosensor (1)
- birth weight (1)
- body height (1)
- body mass index (1)
- breath analysis (1)
- carbon cycling (1)
- carbon limitation (1)
- carbon sequestration (1)
- cardiac development (1)
- cardiomyocyte (1)
- cardiovascular system (1)
- catch-up growth (1)
- cell (1)
- cell culture (1)
- cellulose polymeric organic matter (1)
- chemodiversity (1)
- chloroplast isolation (1)
- ciliate predators (1)
- classical swine fever (1)
- climate adaptation (1)
- cold (1)
- cold stress (1)
- collagen (1)
- comparison (1)
- composition (1)
- conformational change (1)
- construction (1)
- crop losses (1)
- crowdsourcing (1)
- cyanobacteria sedimentation (1)
- cyanobacterial bloom (1)
- cyclic voltammetry (1)
- cycloeucalenol (1)
- ddRAD (1)
- deep-sea sharks (1)
- developmental canalization (1)
- diabetes (1)
- diel cycle (1)
- diffusion (1)
- digital (1)
- dipeptide (1)
- disease diagnosis (1)
- diversity (1)
- division (1)
- dynamic landscapes (1)
- early experience (1)
- ecological succession (1)
- economy (1)
- ecophysiology (1)
- egg ratio (1)
- electrosynthesis (1)
- elephants (1)
- emotional stress (1)
- endocardium (1)
- endophytes (1)
- environmental change (1)
- environmental gradient (1)
- environmental reconstruction (1)
- enzymatic activities (1)
- epitope imprinting (1)
- epitope prediction (1)
- eutrophication (1)
- exploitation (1)
- exposure time (1)
- extracellular enzymes (1)
- extracellular matrix (1)
- extracellular signaling (1)
- falling groundwater level (1)
- fatty acid composition (1)
- fear (1)
- female preference (1)
- fitness gradient (1)
- fitness response (1)
- fluorescence (1)
- fluorescence correlation spectroscopy (1)
- fluorescence fluctuation microscopy (1)
- fluorescence microscopy (1)
- fluorescent image analysis (1)
- food chain (1)
- food-web efficiency (1)
- fractionation factors (1)
- frame index (1)
- full-length transcriptome (1)
- functional (1)
- functional morphology (1)
- fungi (1)
- galactose-decorated monomer (1)
- gas chromatography-mass spectrometry (GC-MS) (1)
- genetic (1)
- genetic accommodation (1)
- genetic rescue (1)
- giraffe (1)
- giraffe conservation (1)
- global change (1)
- glucan phosphorylase (1)
- glucose metabolism (1)
- glycated peptide (1)
- glyco-inside nano-assemblies (1)
- granule number per chloroplast (1)
- grasslands ecosystem (1)
- guard cell (1)
- handgrip strength (1)
- heart regeneration (1)
- heat (1)
- heat shock protein (1)
- homogenisation (1)
- homology (1)
- host– pathogen dynamics (1)
- human induced pluripotent stem cell (1)
- human sulfite oxidase (1)
- hybridization capture (1)
- hybridoma (1)
- image processing (1)
- immobilized enzyme (1)
- immune cell population (1)
- incubation (1)
- individual differences (1)
- individual‐ based model (1)
- indolactams (1)
- infection (1)
- influenza-A (1)
- innovation (1)
- insect behavior (1)
- insulin resistance (1)
- interaction (1)
- intra-organ-communication (1)
- intraspecific trait variation (1)
- introgression (1)
- in situ scanning (1)
- ion mobility spectrometry (1)
- kelp (1)
- lake stratification (1)
- last glacial (1)
- lifetime (1)
- light intensity (1)
- light variability (1)
- limits (1)
- lipid-ratio (1)
- litter decomposition (1)
- liver (1)
- lung organoid (1)
- major histocompatibility complex (1)
- male philopatry (1)
- malnutrition (1)
- many-to-one genotype–phenotype map (1)
- mark-release-recapture (1)
- mayfly (1)
- mesophyll cell (1)
- metabarcoding (1)
- metacommunity (1)
- microalgal resource (1)
- microbial ecology (1)
- microcystin (1)
- microtubule-organizing center (1)
- migrants (1)
- mitochondrial phylogeny (1)
- mitogenomes (1)
- mitosis (1)
- molecular modeling (1)
- molybdenum cofactor (1)
- monoclonal antibody (1)
- morphology (1)
- mouse (1)
- movement ecology (1)
- movement patterns (1)
- multienzyme electrode (1)
- museum specimens (1)
- myocardium (1)
- neophilia (1)
- neophobia (1)
- niche width (1)
- nitrate reductase (1)
- no threshold for stunting (1)
- noise color (1)
- non-specific (1)
- nonribosomal peptide synthetases (1)
- novelty (1)
- number and brightness (1)
- nutrient cycling (1)
- nutrient leaching (1)
- nutrient spike (1)
- obesity (1)
- odor (1)
- olfaction (1)
- olfactory (1)
- oligomerization (1)
- ontogeny (1)
- opportunistic behaviour (1)
- optical microscopy (1)
- oxygen scavenger (1)
- paleoclimate (1)
- paleoenvironments (1)
- partial protandry (1)
- past biosphere (1)
- pathogens (1)
- peptide imprinting (1)
- peptides (1)
- phenotypic plasticity (1)
- phosphoglucan water dikinase (1)
- photoresponse (1)
- photosynthesis (1)
- physiology (1)
- phytodiversity (1)
- picocyanobacteria diversity (1)
- plant functional trait (1)
- plant pathology (1)
- plants (1)
- pollen (1)
- polyamide (1)
- polystyrene (1)
- population cycles (1)
- population demography (1)
- population growth rate (1)
- predator (1)
- predator trait variation (1)
- predator-prey systems (1)
- priming (1)
- problem solving (1)
- production (1)
- protein (1)
- protein-metabolite (1)
- psychrotolerant (1)
- pulse perturbation (1)
- random forest (1)
- random forests (1)
- reaction norms (1)
- recombination (1)
- redox gating (1)
- regime shift (1)
- regulation of growth (1)
- retinoid-binding protein (1)
- robustness (1)
- rodent (1)
- rotifers (1)
- scRNA-seq (1)
- scale-dependency (1)
- scaled mass index (1)
- secular trend (1)
- sedaDNA (1)
- sediment core (1)
- sediment traps (1)
- self-assembled molecular monolayers (1)
- self-organisation (1)
- silica beads (1)
- silviculture (1)
- single-crystal gold electrodes (1)
- sitosterol (1)
- skull (1)
- snake evolution (1)
- social-economic-political-emotional (1)
- soil (1)
- soil aggregation (1)
- soil organic carbon (1)
- soil pH (1)
- soil respiration (1)
- source-sink dynamics (1)
- spatio-temporal pattern (1)
- species abundance (1)
- spectrometry (IMS) (1)
- spectroscopy (1)
- standard metabolic rate (1)
- standing long jump (1)
- starch (1)
- starch granule (1)
- starch granule morphology (1)
- starch granule number per chloroplast (1)
- starch granule size (1)
- static and dynamic light scattering (1)
- sterol (1)
- stochastic fluctuations (1)
- stress (1)
- structural diversity (1)
- supply (1)
- tRNA thio modifications (1)
- taxonomy (1)
- teleocidin (1)
- teleost (1)
- temporal variability (1)
- terpenoids (1)
- tissue stiffness (1)
- tissue types (1)
- titin (1)
- tools (1)
- top (1)
- trait diversity (1)
- trait-based aggregate model (1)
- trait-environment relationship (1)
- transcriptomics (1)
- triaxial acceleration (1)
- trimethylamine N-oxide (1)
- tritrophic food web (1)
- trnL (1)
- tunnelling spectroscopy (1)
- vegetation change (1)
- viologen (1)
- virus (1)
- virus assembly (1)
- water dikinase (1)
- weight-to-height ratio (1)
- woody biomass (1)
- zebrafish (1)
- δ13C (1)
- δ15N (1)
Institute
- Institut für Biochemie und Biologie (128) (remove)
Wildfires, as a key disturbance in forest ecosystems, are shaping the world's boreal landscapes. Changes in fire regimes are closely linked to a wide array of environmental factors, such as vegetation composition, climate change, and human activity. Arctic and boreal regions and, in particular, Siberian boreal forests are experiencing rising air and ground temperatures with the subsequent degradation of permafrost soils leading to shifts in tree cover and species composition. Compared to the boreal zones of North America or Europe, little is known about how such environmental changes might influence long-term fire regimes in Russia. The larch-dominated eastern Siberian deciduous boreal forests differ markedly from the composition of other boreal forests, yet data about past fire regimes remain sparse. Here, we present a high-resolution macroscopic charcoal record from lacustrine sediments of Lake Khamra (southwest Yakutia, Siberia) spanning the last ca. 2200 years, including information about charcoal particle sizes and morphotypes. Our results reveal a phase of increased charcoal accumulation between 600 and 900 CE, indicative of relatively high amounts of burnt biomass and high fire frequencies. This is followed by an almost 900-year-long period of low charcoal accumulation without significant peaks likely corresponding to cooler climate conditions. After 1750 CE fire frequencies and the relative amount of biomass burnt start to increase again, coinciding with a warming climate and increased anthropogenic land development after Russian colonization. In the 20th century, total charcoal accumulation decreases again to very low levels despite higher fire frequency, potentially reflecting a change in fire management strategies and/or a shift of the fire regime towards more frequent but smaller fires. A similar pattern for different charcoal morphotypes and comparison to a pollen and non-pollen palynomorph (NPP) record from the same sediment core indicate that broad-scale changes in vegetation composition were probably not a major driver of recorded fire regime changes. Instead, the fire regime of the last two millennia at Lake Khamra seems to be controlled mainly by a combination of short-term climate variability and anthropogenic fire ignition and suppression.
Mammalian aldehyde oxidases (AOX) are molybdo-flavoenzymes of pharmacological and pathophysiologic relevance that are involved in phase I drug metabolism and, as a product of their enzymatic activity, are also involved in the generation of reactive oxygen species. So far, the physiologic role of aldehyde oxidase 1 in the human body remains unknown. The human enzyme hAOX1 is characterized by a broad substrate specificity, oxidizing aromatic/aliphatic aldehydes into their corresponding carboxylic acids, and hydroxylating various heteroaromatic rings. The enzyme uses oxygen as terminal electron acceptor to produce hydrogen peroxide and superoxide during turnover. Since hAOX1 and, in particular, some natural variants produce not only H2O2 but also high amounts of superoxide, we investigated the effect of both ROS molecules on the enzymatic activity of hAOX1 in more detail. We compared hAOX1 to the high-O-2(.-)-producing natural variant L438V for their time-dependent inactivation with H2O2/O-2(.-) during substrate turnover. We show that the inactivation of the hAOX1 wild-type enzyme is mainly based on the production of hydrogen peroxide, whereas for the variant L438V, both hydrogen peroxide and superoxide contribute to the time-dependent inactivation of the enzyme during turnover. Further, the level of inactivation was revealed to be substrate-dependent: using substrates with higher turnover numbers resulted in a faster inactivation of the enzymes. Analysis of the inactivation site of the enzyme identified a loss of the terminal sulfido ligand at the molybdenum active site by the produced ROS during turnover.
Photodynamic therapy (PDT) is a mild but effective method to treat certain types of cancer upon irradiation with visible light. Here, three isomeric methylpyridinium alkynylanthracenes 1op were evaluated as sensitizers for PDT. Upon irradiation with blue or green light, all three compounds show the ability to initiate strand breaks of plasmid DNA. The mayor species responsible for cleavage is singlet oxygen (O-1(2)) as confirmed by scavenging reagents. Only isomers 1m and 1p can be incorporated into HeLa cells, whereas isomer 1o cannot permeate through the membrane. While isomer 1m targets the cell nucleus, isomer 1p assembles in the cellular cytoplasm and impacts the cellular integrity. This is in accordance with a moderate toxicity of 1p in the dark, whereas 1m exhibits no dark toxicity. Both isomers are suitable as PDT reagents, with a CC50 of 3 mu m and 75 nm, for 1p and 1m, respectively. Thus, derivative 1m, which can be easily synthesized, becomes an interesting candidate for cancer therapy.
Heteromeric HSFA2/HSFA3 complexes drive transcriptional memory after heat stress in Arabidopsis
(2021)
Adaptive plasticity in stress responses is a key element of plant survival strategies. For instance, moderate heat stress (HS) primes a plant to acquire thermotolerance, which allows subsequent survival of more severe HS conditions. Acquired thermotolerance is actively maintained over several days (HS memory) and involves the sustained induction of memory-related genes. Here we show that FORGETTER3/ HEAT SHOCK TRANSCRIPTION FACTOR A3 (FGT3/HSFA3) is specifically required for physiological HS memory and maintaining high memory-gene expression during the days following a HS exposure. HSFA3 mediates HS memory by direct transcriptional activation of memory-related genes after return to normal growth temperatures. HSFA3 binds HSFA2, and in vivo both proteins form heteromeric complexes with additional HSFs. Our results indicate that only complexes containing both HSFA2 and HSFA3 efficiently promote transcriptional memory by positively influencing histone H3 lysine 4 (H3K4) hyper-methylation. In summary, our work defines the major HSF complex controlling transcriptional memory and elucidates the in vivo dynamics of HSF complexes during somatic stress memory. Moderate heat stress primes plants to acquire tolerance to subsequent, more severe heat stress. Here the authors show that the HSFA3 transcription factor forms a heteromeric complex with HSFA2 to sustain activated transcription of genes required for acquired thermotolerance by promoting H3K4 hyper-methylation.
Trait variation among heterospecific and conspecific organisms may substantially affect community and food web dynamics. While the relevance of competition and feeding traits have been widely studied for different consumer species, studies on intraspecific differences are more scarce, partly owing to difficulties in distinguishing different clones of the same species. Here, we investigate how intraspecific trait variation affects the competition between the freshwater ciliates Euplotes octocarinatus and Coleps hirtus in a nitrogen-limited chemostat system. The ciliates competed for the microalgae Cryptomonas sp. (Cry) and Navicula pelliculosa (Nav), and the bacteria present in the cultures over a period of 33 days. We used monoclonal Euplotes and three different Coleps clones (Col 1, Col 2, and Col 3) in the experiment that could be distinguished by a newly developed rDNA-based molecular assay based on the internal transcribed spacer (ITS) regions. While Euplotes feeds on Cry and on bacteria, the Coleps clones cannot survive on bacteria alone but feed on both Cry and Nav with clone-specific rates. Experimental treatments comprised two-species mixtures of Euplotes and one or all of the three different Coleps clones, respectively. We found intraspecific variation in the traits "selectivity" and "maximum ingestion rate" for the different algae to significantly affect the competitive outcome between the two ciliate species. As Nav quickly escaped top-down control and likely reached a state of low food quality, ciliate competition was strongly determined by the preference of different Coleps clones for Cry as opposed to feeding on Nav. In addition, the ability of Euplotes to use bacteria as an alternative food source strengthened its persistence once Cry was depleted. Hence, trait variation at both trophic levels codetermined the population dynamics and the outcome of species competition.
Retinol-binding protein 4 (RBP4) is the major transport protein for retinol in blood. Recent evidence from genetic mouse models shows that circulating RBP4 derives exclusively from hepatocytes. Because RBP4 is elevated in obesity and associates with the development of glucose intolerance and insulin resistance, we tested whether a liver-specific overexpression of RBP4 in mice impairs glucose homeostasis. We used adeno-associated viruses (AAV) that contain a highly liver-specific promoter to drive expression of murine RBP4 in livers of adult mice. The resulting increase in serum RBP4 levels in these mice was comparable with elevated levels that were reported in obesity. Surprisingly, we found that increasing circulating RBP4 had no effect on glucose homeostasis. Also during a high-fat diet challenge, elevated levels of RBP4 in the circulation failed to aggravate the worsening of systemic parameters of glucose and energy homeostasis. These findings show that liver-secreted RBP4 does not impair glucose homeostasis. We conclude that a modest increase of its circulating levels in mice, as observed in the obese, insulin-resistant state, is unlikely to be a causative factor for impaired glucose homeostasis.
There has been a growing awareness that graphing is an essential part of the science curriculum. While much research has focused on student conceptions and abilities regarding graphical representations, only few studies have investigated what teachers think about them and how they use graphs in science class. The purpose of this study is to explore educational beliefs, motivation, and teaching practices of German secondary biology teachers regarding graph construction. Via questionnaire surveys, 71 teachers from different regions in Germany rated their beliefs and motivation as well as the frequency of different graph construction activities in biology class. The teachers surveyed in this study were quite motivated in their teaching of graph construction. Furthermore, they tended to believe that graph construction should be practiced explicitly in biology class and that students should learn clear strategies for constructing graphs. We found that teaching subjects and own research experience make a difference in teachers' beliefs and motivation regarding graph construction in biology class. The self-report on classroom practices revealed that participants may provide limited opportunities for students to experience graphing as a social and iterative practice. Implications are drawn for teacher education and professional development as well as for further research in teacher education contexts.
Floral volatiles and reward traits are major drivers for the behavior of mutualistic as well as antagonistic flower visitors, i.e., pollinators and florivores. These floral traits differ tremendously between species, but intraspecific differences and their consequences on organism interactions remain largely unknown. Floral volatile compounds, such as terpenoids, function as cues to advertise rewards to pollinators, but should at the same time also repel florivores. The reward composition, e.g., protein and lipid contents in pollen, differs between individuals of distinct plant families. Whether the nutritional value of rewards within the same plant species is linked to their chemotypes, which differ in their pattern of specialized metabolites, has yet not been investigated. In the present study, we compared Tanacetum vulgare plants of five terpenoid chemotypes with regard to flower production, floral headspace volatiles, pollen macronutrient and terpenoid content, and floral attractiveness to florivorous beetles. Our analyses revealed remarkable differences between the chemotypes in the amount and diameter of flower heads, duration of bloom period, and pollen nutritional quality. The floral headspace composition of pollen-producing mature flowers, but not of premature flowers, was correlated to that of pollen and leaves in the same plant individual. For two chemotypes, florivorous beetles discriminated between the scent of mature and premature flower heads and preferred the latter. In semi-field experiments, the abundance of florivorous beetles and flower tissue miners differed between T. vulgare chemotypes. Moreover, the scent environment affected the choice and beetles were more abundant in homogenous plots composed of one single chemotype than in plots with different neighboring chemotypes. In conclusion, flower production, floral metabolic composition and pollen quality varied to a remarkable extend within the species T. vulgare, and the attractiveness of floral scent differed also intra-individually with floral ontogeny. We found evidence for a trade-off between pollen lipid content and pollen amount on a per-plant-level. Our study highlights that chemotypes which are more susceptible to florivory are less attacked when they grow in the neighborhood of other chemotypes and thus gain a benefit from high overall chemodiversity.
Signaling pathways in biological systems rely on specific interactions between multiple biomolecules. Fluorescence fluctuation spectroscopy provides a powerful toolbox to quantify such interactions directly in living cells. Cross-correlation analysis of spectrally separated fluctuations provides information about intermolecular interactions but is usually limited to two fluorophore species. Here, we present scanning fluorescence spectral correlation spectroscopy (SFSCS), a versatile approach that can be implemented on commercial confocal microscopes, allowing the investigation of interactions between multiple protein species at the plasma membrane. We demonstrate that SFSCS enables cross-talk-free cross-correlation, diffusion, and oligomerization analysis of up to four protein species labeled with strongly overlapping fluorophores. As an example, we investigate the interactions of influenza A virus (IAV) matrix protein 2 with two cellular host factors simultaneously. We furthermore apply raster spectral image correlation spectroscopy for the simultaneous analysis of up to four species and determine the stoichiometry of ternary IAV polymerase complexes in the cell nucleus.
Plastic pollution is an increasing environmental problem, but a comprehensive understanding of its effect in the environment is still missing. The wide variety of size, shape, and polymer composition of plastics impedes an adequate risk assessment. We investigated the effect of differently sized polystyrene beads (1-, 3-, 6-µm; PS) and polyamide fragments (5–25 µm, PA) and non-plastics items such as silica beads (3-µm, SiO2) on the population growth, reproduction (egg ratio), and survival of two common aquatic micro invertebrates: the rotifer species Brachionus calyciflorus and Brachionus fernandoi. The MPs were combined with food quantity, limiting and saturating food concentration, and with food of different quality. We found variable fitness responses with a significant effect of 3-µm PS on the population growth rate in both rotifer species with respect to food quantity. An interaction between the food quality and the MPs treatments was found in the reproduction of B. calyciflorus. PA and SiO2 beads had no effect on fitness response. This study provides further evidence of the indirect effect of MPs in planktonic rotifers and the importance of testing different environmental conditions that could influence the effect of MPs.
Human aldehyde oxidase (hAOX1) is mainly present in the liver and has an emerging role in drug metabolism, since it accepts a wide range of molecules as substrates and inhibitors. Herein, we employed an integrative approach by combining NMR, X-ray crystallography, and enzyme inhibition kinetics to understand the inhibition modes of three hAOX1 inhibitors-thioridazine, benzamidine, and raloxifene. These integrative data indicate that thioridazine is a noncompetitive inhibitor, while benzamidine presents a mixed type of inhibition. Additionally, we describe the first crystal structure of hAOX1 in complex with raloxifene. Raloxifene binds tightly at the entrance of the substrate tunnel, stabilizing the flexible entrance gates and elucidating an unusual substrate-dependent mechanism of inhibition with potential impact on drug-drug interactions. This study can be considered as a proof-of-concept for an efficient experimental screening of prospective substrates and inhibitors of hAOX1 relevant in drug discovery.
Ecological niche models (ENMs) are often used to investigate how climatic variables from known occurrence records can estimate potential species range distribution. Although climate-based ENMs provide critical baseline information, the inclusion of non-climatic predictors related to vegetation cover might generate more realistic scenarios. This assumption is particularly relevant for species with life-history traits related to forest habitats and sensitive to habitat loss and fragmentation. Here, we developed ENMs for 36 Atlantic Forest endemic birds considering two sets of predictor variables: (i) climatic variables only and (ii) climatic variables combined with the percentage of remaining native vegetation. We hypothesized that the inclusion of native vegetation data would decrease the potential range distribution of forest-dependent species by limiting their occurrence in regions harboring small areas of native vegetation habitats, despite otherwise favorable climatic conditions. We also expected that habitat restriction in the climate-vegetation models would be more pronounced for highly forest-dependent birds. The inclusion of vegetation data in the modeling procedures restricted the final distribution ranges of 22 out of 36 modeled species, while the 14 remaining presented an expansion of their ranges. We observed that species with high and medium forest dependency showed higher restriction in range size predictions between predictor sets than species with low forest dependency, which showed no alteration or range expansion. Overall, our results suggest that ENMs based on climatic and landscape variables may be a useful tool for conservationists to better understand the dynamic of bird species distributions in threatened and highly fragmented regions such as the Atlantic Forest hotspot.(c) 2021 Associacao Brasileira de Cie circumflex accent ncia Ecol ogica e Conservacao. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/ ).
Relationships between climate, species composition, and species richness are of particular importance for understanding how boreal ecosystems will respond to ongoing climate change. This study aims to reconstruct changes in terrestrial vegetation composition and taxa richness during the glacial Late Pleistocene and the interglacial Holocene in the sparsely studied southeastern Yakutia (Siberia) by using pollen and sedimentary ancient DNA (sedaDNA) records. Pollen and sedaDNA metabarcoding data using the trnL g and h markers were obtained from a sediment core from Lake Bolshoe Toko. Both proxies were used to reconstruct the vegetation composition, while metabarcoding data were also used to investigate changes in plant taxa richness. The combination of pollen and sedaDNA approaches allows a robust estimation of regional and local past terrestrial vegetation composition around Bolshoe Toko during the last similar to 35,000 years. Both proxies suggest that during the Late Pleistocene, southeastern Siberia was covered by open steppe-tundra dominated by graminoids and forbs with patches of shrubs, confirming that steppe-tundra extended far south in Siberia. Both proxies show disturbance at the transition between the Late Pleistocene and the Holocene suggesting a period with scarce vegetation, changes in the hydrochemical conditions in the lake, and in sedimentation rates. Both proxies document drastic changes in vegetation composition in the early Holocene with an increased number of trees and shrubs and the appearance of new tree taxa in the lake's vicinity. The sedaDNA method suggests that the Late Pleistocene steppe-tundra vegetation supported a higher number of terrestrial plant taxa than the forested Holocene. This could be explained, for example, by the "keystone herbivore" hypothesis, which suggests that Late Pleistocene megaherbivores were able to maintain a high plant diversity. This is discussed in the light of the data with the broadly accepted species-area hypothesis as steppe-tundra covered such an extensive area during the Late Pleistocene.
Starch is a natural storage carbohydrate in plants and algae. It consists of two relatively simple homo-biopolymers, amylopectin and amylose, with only alpha-1,4 and alpha-1,6 linked glucosyl units. Starch is an essential source of nutrition and animal food, as well as an important raw material for industry. However, despite increasing knowledge, detailed information about its structure and turnover are largely lacking. In the last decades, most data were generated using bulk experiments, a method which obviously presents limitations regarding a deeper understanding of the starch metabolism. Here, we discuss some unavoidable questions arising from the existing data. We focus on a few examples related to starch biosynthesis, degradation, and structure where these limitations strongly emerge. Closing these knowledge gaps will also be extremely important for taking the necessary steps in order to set up starch-providing crops for the challenges of the ongoing climate changes, as well as for increasing the usability of starches for industrial applications by biotechnology.
Organisms often employ ecophysiological strategies to exploit environmental conditions and ensure bio-energetic success. However, the many complexities involved in the differential expression and flexibility of these strategies are rarely fully understood. Therefore, for the first time, using a three-part cross-disciplinary laboratory experimental analysis, we investigated the diversity and plasticity of photoresponsive traits employed by one family of environmentally contrasting, ecologically important phytoflagellates. The results demonstrated an extensive inter-species phenotypic diversity of behavioural, physiological, and compositional photoresponse across the Chlamydomonadaceae, and a multifaceted intra-species phenotypic plasticity, involving a broad range of beneficial photoacclimation strategies, often attributable to environmental predisposition and phylogenetic differentiation. Deceptively diverse and sophisticated strong (population and individual cell) behavioural photoresponses were observed, with divergence from a general preference for low light (and flexibility) dictated by intra-familial differences in typical habitat (salinity and trophy) and phylogeny. Notably, contrasting lower, narrow, and flexible compared with higher, broad, and stable preferences were observed in freshwater vs. brackish and marine species. Complex diversity and plasticity in physiological and compositional photoresponses were also discovered. Metabolic characteristics (such as growth rates, respiratory costs and photosynthetic capacity, efficiency, compensation and saturation points) varied elaborately with species, typical habitat (often varying more in eutrophic species, such as Chlamydomonas reinhardtii), and culture irradiance (adjusting to optimise energy acquisition and suggesting some propensity for low light). Considerable variations in intracellular pigment and biochemical composition were also recorded. Photosynthetic and accessory pigments (such as chlorophyll a, xanthophyll-cycle components, chlorophyll a:b and chlorophyll a:carotenoid ratios, fatty acid content and saturation ratios) varied with phylogeny and typical habitat (to attune photosystem ratios in different trophic conditions and to optimise shade adaptation, photoprotection, and thylakoid architecture, particularly in freshwater environments), and changed with irradiance (as reaction and harvesting centres adjusted to modulate absorption and quantum yield). The complex, concomitant nature of the results also advocated an integrative approach in future investigations. Overall, these nuanced, diverse, and flexible photoresponsive traits will greatly contribute to the functional ecology of these organisms, addressing environmental heterogeneity and potentially shaping individual fitness, spatial and temporal distribution, prevalence, and ecosystem dynamics.
It is well known that functional diversity strongly affects ecosystem functioning. However, even in rather simple model communities consisting of only two or, at best, three trophic levels, the relationship between multitrophic functional diversity and ecosystem functioning appears difficult to generalize, because of its high contextuality. In this study, we considered several differently structured tritrophic food webs, in which the amount of functional diversity was varied independently on each trophic level. To achieve generalizable results, largely independent of parametrization, we examined the outcomes of 128,000 parameter combinations sampled from ecologically plausible intervals, with each tested for 200 randomly sampled initial conditions. Analysis of our data was done by training a random forest model. This method enables the identification of complex patterns in the data through partial dependence graphs, and the comparison of the relative influence of model parameters, including the degree of diversity, on food-web properties. We found that bottom-up and top-down effects cascade simultaneously throughout the food web, intimately linking the effects of functional diversity of any trophic level to the amount of diversity of other trophic levels, which may explain the difficulty in unifying results from previous studies. Strikingly, only with high diversity throughout the whole food web, different interactions synergize to ensure efficient exploitation of the available nutrients and efficient biomass transfer to higher trophic levels, ultimately leading to a high biomass and production on the top level. The temporal variation of biomass showed a more complex pattern with increasing multitrophic diversity: while the system initially became less variable, eventually the temporal variation rose again because of the increasingly complex dynamical patterns. Importantly, top predator diversity and food-web parameters affecting the top trophic level were of highest importance to determine the biomass and temporal variability of any trophic level. Overall, our study reveals that the mechanisms by which diversity influences ecosystem functioning are affected by every part of the food web, hampering the extrapolation of insights from simple monotrophic or bitrophic systems to complex natural food webs.
Insights in electrosynthesis, target binding, and stability of peptide-imprinted polymer nanofilms
(2021)
Molecularly imprinted polymer (MIP) nanofilms have been successfully implemented for the recognition of different target molecules: however, the underlying mechanistic details remained vague.
This paper provides new insights in the preparation and binding mechanism of electrosynthesized peptide-imprinted polymer nanofilms for selective recognition of the terminal pentapeptides of the beta-chains of human adult hemoglobin, HbA, and its glycated form HbA1c.
To differentiate between peptides differing solely in a glucose adduct MIP nanofilms were prepared by a two-step hierarchical electrosynthesis that involves first the chemisorption of a cysteinyl derivative of the pentapeptide followed by electropolymerization of scopoletin.
This approach was compared with a random single-step electrosynthesis using scopo-letin/pentapeptide mixtures. Electrochemical monitoring of the peptide binding to the MIP nanofilms by means of redox probe gating revealed a superior affinity of the hierarchical approach with a Kd value of 64.6 nM towards the related target.
Changes in the electrosynthesized non-imprinted polymer and MIP nanofilms during chemical, electrochemical template removal and rebinding were substantiated in situ by monitoring the characteristic bands of both target peptides and polymer with surface enhanced infrared absorption spectroscopy.
This rational approach led to MIPs with excellent selectivity and provided key mechanistic insights with respect to electrosynthesis, rebinding and stability of the formed MIPs.
Background and aims:
The objective of the present work was to determine to what extent sleep quality may mediate the association between chronodisruption (CD) and metabolic syndrome (MS), and between CD and body composition (BC).
Methodology:
Cross-sectional study which included 300 adult health workers, 150 of whom were night shift workers and thereby exposed to CD. Diagnosis of MS was made based on Adult Treatment Panel III criteria. Sleep quality was measured using the Pittsburgh Sleep Quality Index. Body mass index (BMI), fat mass percentage, and visceral fat percentage were measured as indicators of body composition (BC). Data were analyzed using logistic, linear regression and structural equation models.
Results:
The odds of health workers exposed to CD to suffer MS was 22.13 (IC95 8.68-66.07) when the model was adjusted for age, gender, physical activity and energy consumption. CD was also significantly associated with an increase in fat mass and visceral fat percentages, but not to BMI. Surprisingly, there was not enough evidence supporting the hypothesis that sleep quality contributes to the association between CD and MS or between CD and BC.
Conclusions:
Sleep quality does not mediate the negative effects of CD on MS nor on BC.
As autotrophic organisms, plants capture light energy to convert carbon dioxide into ATP, nicotinamide adenine dinucleotide phosphate (NADPH), and sugars, which are essential for the biosynthesis of building blocks, storage, and growth. At night, metabolism and growth can be sustained by mobilizing carbon (C) reserves. In response to changing environmental conditions, such as light-dark cycles, the small-molecule regulation of enzymatic activities is critical for reprogramming cellular metabolism. We have recently demonstrated that proteogenic dipeptides, protein degradation products, act as metabolic switches at the interface of proteostasis and central metabolism in both plants and yeast. Dipeptides accumulate in response to the environmental changes and act via direct binding and regulation of critical enzymatic activities, enabling C flux distribution. Here, we provide evidence pointing to the involvement of dipeptides in the metabolic rewiring characteristics for the day-night cycle in plants. Specifically, we measured the abundance of 13 amino acids and 179 dipeptides over short- (SD) and long-day (LD) diel cycles, each with different light intensities. Of the measured dipeptides, 38 and eight were characterized by day-night oscillation in SD and LD, respectively, reaching maximum accumulation at the end of the day and then gradually falling in the night. Not only the number of dipeptides, but also the amplitude of the oscillation was higher in SD compared with LD conditions. Notably, rhythmic dipeptides were enriched in the glucogenic amino acids that can be converted into glucose. Considering the known role of Target of Rapamycin (TOR) signaling in regulating both autophagy and metabolism, we subsequently investigated whether diurnal fluctuations of dipeptides levels are dependent on the TOR Complex (TORC). The Raptor1b mutant (raptor1b), known for the substantial reduction of TOR kinase activity, was characterized by the augmented accumulation of dipeptides, which is especially pronounced under LD conditions. We were particularly intrigued by the group of 16 dipeptides, which, based on their oscillation under SD conditions and accumulation in raptor1b, can be associated with limited C availability or photoperiod. By mining existing protein-metabolite interaction data, we delineated putative protein interactors for a representative dipeptide Pro-Gln. The obtained list included enzymes of C and amino acid metabolism, which are also linked to the TORC-mediated metabolic network. Based on the obtained results, we speculate that the diurnal accumulation of dipeptides contributes to its metabolic adaptation in response to changes in C availability. We hypothesize that dipeptides would act as alternative respiratory substrates and by directly modulating the activity of the focal enzymes.
Due to their isolated and often fragmented nature, range margin populations are especially vulnerable to rapid environmental change. To maintain genetic diversity and adaptive potential, gene flow from disjunct populations might therefore be crucial to their survival. Translocations are often proposed as a mitigation strategy to increase genetic diversity in threatened populations. However, this also includes the risk of losing locally adapted alleles through genetic swamping. Human-mediated translocations of southern lineage specimens into northern German populations of the endangered European fire-bellied toad (Bombina bombina) provide an unexpected experimental set-up to test the genetic consequences of an intraspecific introgression from central population individuals into populations at the species range margin. Here, we utilize complete mitochondrial genomes and transcriptome nuclear data to reveal the full genetic extent of this translocation and the consequences it may have for these populations. We uncover signs of introgression in four out of the five northern populations investigated, including a number of introgressed alleles ubiquitous in all recipient populations, suggesting a possible adaptive advantage. Introgressed alleles dominate at the MTCH2 locus, associated with obesity/fat tissue in humans, and the DSP locus, essential for the proper development of epidermal skin in amphibians. Furthermore, we found loci where local alleles were retained in the introgressed populations, suggesting their relevance for local adaptation. Finally, comparisons of genetic diversity between introgressed and nonintrogressed northern German populations revealed an increase in genetic diversity in all German individuals belonging to introgressed populations, supporting the idea of a beneficial transfer of genetic variation from Austria into North Germany.
Northern range margin populations of the European fire-bellied toad (Bombina bombina) have rapidly declined during recent decades. Extensive agricultural land use has fragmented the landscape, leading to habitat disruption and loss, as well as eutrophication of ponds. In Northern Germany (Schleswig-Holstein) and Southern Sweden (Skåne), this population decline resulted in decreased gene flow from surrounding populations, low genetic diversity, and a putative reduction in adaptive potential, leaving populations vulnerable to future environmental and climatic changes. Previous studies using mitochondrial control region and nuclear transcriptome-wide SNP data detected introgressive hybridization in multiple northern B. bombina populations after unreported release of toads from Austria. Here, we determine the impact of this introgression by comparing the body conditions (proxy for fitness) of introgressed and nonintrogressed populations and the genetic consequences in two candidate genes for putative local adaptation (the MHC II gene as part of the adaptive immune system and the stress response gene HSP70 kDa). We detected regional differences in body condition and observed significantly elevated levels of within individual MHC allele counts in introgressed Swedish populations, associated with a tendency toward higher body weight, relative to regional nonintrogressed populations. These differences were not observed among introgressed and nonintrogressed German populations. Genetic diversity in both MHC and HSP was generally lower in northern than Austrian populations. Our study sheds light on the potential benefits of translocations of more distantly related conspecifics as a means to increase adaptive genetic variability and fitness of genetically depauperate range margin populations without distortion of local adaptation.
Averting today's loss of biodiversity and ecosystem services can be achieved through conservation efforts, especially of keystone species. Giraffes (Giraffa camelopardalis) play an important role in sustaining Africa's ecosystems, but are 'vulnerable' according to the IUCN Red List since 2016. Monitoring an animal's behavior in the wild helps to develop and assess their conservation management. One mechanism for remote tracking of wildlife behavior is to attach accelerometers to animals to record their body movement. We tested two different commercially available high-resolution accelerometers, e-obs and Africa Wildlife Tracking (AWT), attached to the top of the heads of three captive giraffes and analyzed the accuracy of automatic behavior classifications, focused on the Random Forests algorithm. For both accelerometers, behaviors of lower variety in head and neck movements could be better predicted (i.e., feeding above eye level, mean prediction accuracy e-obs/AWT: 97.6%/99.7%; drinking: 96.7%/97.0%) than those with a higher variety of body postures (such as standing: 90.7-91.0%/75.2-76.7%; rumination: 89.6-91.6%/53.5-86.5%). Nonetheless both devices come with limitations and especially the AWT needs technological adaptations before applying it on animals in the wild. Nevertheless, looking at the prediction results, both are promising accelerometers for behavioral classification of giraffes. Therefore, these devices when applied to free-ranging animals, in combination with GPS tracking, can contribute greatly to the conservation of giraffes.
Strong as a Hippo’s Heart: Biomechanical Hippo Signaling During Zebrafish Cardiac Development
(2021)
The heart is comprised of multiple tissues that contribute to its physiological functions. During development, the growth of myocardium and endocardium is coupled and morphogenetic processes within these separate tissue layers are integrated. Here, we discuss the roles of mechanosensitive Hippo signaling in growth and morphogenesis of the zebrafish heart. Hippo signaling is involved in defining numbers of cardiac progenitor cells derived from the secondary heart field, in restricting the growth of the epicardium, and in guiding trabeculation and outflow tract formation. Recent work also shows that myocardial chamber dimensions serve as a blueprint for Hippo signaling-dependent growth of the endocardium. Evidently, Hippo pathway components act at the crossroads of various signaling pathways involved in embryonic zebrafish heart development. Elucidating how biomechanical Hippo signaling guides heart morphogenesis has direct implications for our understanding of cardiac physiology and pathophysiology.
Trait means or variance
(2021)
One of the few laws in ecology is that communities consist of few common and many rare taxa. Functional traits may help to identify the underlying mechanisms of this community pattern, since they correlate with different niche dimensions. However, comprehensive studies are missing that investigate the effects of species mean traits (niche position) and intraspecific trait variability (ITV, niche width) on species abundance. In this study, we investigated fragmented dry grasslands to reveal trait-occurrence relationships in plants at local and regional scales. We predicted that (a) at the local scale, species occurrence is highest for species with intermediate traits, (b) at the regional scale, habitat specialists have a lower species occurrence than generalists, and thus, traits associated with stress-tolerance have a negative effect on species occurrence, and (c) ITV increases species occurrence irrespective of the scale. We measured three plant functional traits (SLA = specific leaf area, LDMC = leaf dry matter content, plant height) at 21 local dry grassland communities (10 m × 10 m) and analyzed the effect of these traits and their variation on species occurrence. At the local scale, mean LDMC had a positive effect on species occurrence, indicating that stress-tolerant species are the most abundant rather than species with intermediate traits (hypothesis 1). We found limited support for lower specialist occurrence at the regional scale (hypothesis 2). Further, ITV of LDMC and plant height had a positive effect on local occurrence supporting hypothesis 3. In contrast, at the regional scale, plants with a higher ITV of plant height were less frequent. We found no evidence that the consideration of phylogenetic relationships in our analyses influenced our findings. In conclusion, both species mean traits (in particular LDMC) and ITV were differently related to species occurrence with respect to spatial scale. Therefore, our study underlines the strong scale-dependency of trait-abundance relationships.
Nonribosomal peptides (NRP) are crucial molecular mediators in microbial ecology and provide indispensable drugs. Nevertheless, the evolution of the flexible biosynthetic machineries that correlates with the stunning structural diversity of NRPs is poorly understood. Here, we show that recombination is a key driver in the evolution of bacterial NRP synthetase (NRPS) genes across distant bacterial phyla, which has guided structural diversification in a plethora of NRP families by extensive mixing andmatching of biosynthesis genes. The systematic dissection of a large number of individual recombination events did not only unveil a striking plurality in the nature and origin of the exchange units but allowed the deduction of overarching principles that enable the efficient exchange of adenylation (A) domain substrates while keeping the functionality of the dynamic multienzyme complexes. In the majority of cases, recombination events have targeted variable portions of the A(core) domains, yet domain interfaces and the flexible A(sub) domain remained untapped. Our results strongly contradict the widespread assumption that adenylation and condensation (C) domains coevolve and significantly challenge the attributed role of C domains as stringent selectivity filter during NRP synthesis. Moreover, they teach valuable lessons on the choice of natural exchange units in the evolution of NRPS diversity, which may guide future engineering approaches.
Elaeidobius kamerunicus Faust. (Coleoptera: Curculionidae) is an essential insect pollinator in oil palm plantations. Recently, researches have been undertaken to improve pollination efficiency using this species. A fundamental understanding of the genes related to this pollinator behavior is necessary to achieve this goal. Here, we present the draft genome sequence, annotation, and simple sequence repeat (SSR) marker data for this pollinator. In total, 34.97 Gb of sequence data from one male individual (monoisolate) were obtained using Illumina short-read platform NextSeq 500. The draft genome assembly was found to be 269.79 Mb and about 59.9% of completeness based on Benchmarking Universal Single-Copy Orthologs (BUSCO) assessment. Functional gene annotation predicted about 26.566 genes. Also, a total of 281.668 putative SSR markers were identified. This draft genome sequence is a valuable resource for understanding the population genetics, phylogenetics, dispersal patterns, and behavior of this species.
Coherent network partitions
(2021)
We continue to study coherent partitions of graphs whereby the vertex set is partitioned into subsets that induce biclique spanned subgraphs. The problem of identifying the minimum number of edges to obtain biclique spanned connected components (CNP), called the coherence number, is NP-hard even on bipartite graphs. Here, we propose a graph transformation geared towards obtaining an O (log n)-approximation algorithm for the CNP on a bipartite graph with n vertices. The transformation is inspired by a new characterization of biclique spanned subgraphs. In addition, we study coherent partitions on prime graphs, and show that finding coherent partitions reduces to the problem of finding coherent partitions in a prime graph. Therefore, these results provide future directions for approximation algorithms for the coherence number of a given graph.
This paper presents two new pollen records and quantitative climate reconstructions from northern Chukotka documenting environmental changes over the last 27.9 ka. Open tundra- and steppe-like habitats dominated between 27.9 and 18.7 cal. ka BP. Betula and Alnus shrubs might have grown in sheltered microhabitats but disappeared after 18.7 cal. ka BP. Although the climate was rather harsh, local herb-dominated communities supported herbivores as is evident by the presence of coprophilous spores in the sediments. The increase in Salix and Cyperaceae similar to 16.1 cal. ka BP suggests climate amelioration. Shrub Betula appeared similar to 15.9 cal. ka BP, and became dominant after similar to 15.52 cal. ka BP, whilst typical steppe communities drastically reduced. Very high presence of Botryococcus in the Lateglacial sediments reflects widespread shallow habitats, probably due to lake level increase. Shrub Alnus became common after similar to 13 cal. ka BP reflecting further climate amelioration. Simultaneously, herb communities gradually decreased in the vegetation reaching a minimum similar to 11.8 cal. ka BP. A gradual decrease of algae remains suggests a reduction of shallow-water habitats. Shrubby and graminoid tundra was dominant similar to 11.8-11.1 cal. ka BP, later Salix stands significantly decreased. The forest-tundra ecotone established in the Early Holocene, shortly after 11.1 cal. ka BP. Low contents of green algae in the Early Holocene sediments likely reflect deeper aquatic conditions. The most favourable climate conditions were between similar to 10.6 and 7 cal. ka BP. Vegetation became similar to the modern after similar to 7 cal. ka BP but Pinus pumila came to the Ilirney area at about 1.2 cal. ka BP. It is important to emphasize that the study area provided refugia for Betula and Alnus during MIS 2. It is also notable that our records do not reflect evidence of Younger Dryas cooling, which is inconsistent with some regional environmental records but in good accordance with some others.