Predominant female care in the beetle Lethrus apterus with supposedly biparental care

Although intensive care for offspring by both parents is rare in arthropods, it occurs in some species including the beetle Lethrus apterus. According to previous publications, in this species the male collects leaves, which are used by the female to form balls in the underground nest burrow. These balls serve as food for the hatched offspring. Most knowledge about the behavior of this species is based on information collected more than a century ago. Therefore, we investigated above‐ground breeding behavior and the status of nest burrows of this beetle in its natural habitat in Hungary. Our results suggest that contrary to previously documented cases, above‐ground parental care, i.e. the collection of leaves, is done predominantly not by the males but the females. Further research is needed to understand the role of the sexes in parental care in this species and to explain the discrepancy between the previously documented cases and the results we report here.     

Two types of cyclic GMP binding site associated with the cyclic AMP-dependent protein kinase from lymphocytes

Low- and high-affinity binding sites for cyclic GMP were found to be associated with the cyclic AMP-dependent protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) from human tonsillar lymphocytes, but neither of them was identical with the cyclic AMP binding site.The enzyme activated by cyclic GMP phosphorylated the same site of calf thymus H2b histone as the cyclic AMP activated enzyme; however, more complex kinetics of activation were found with cyclic GMP.Two classes of cyclic GMP binding site were demonstrated by kinetic analysis of cyclic [³H]GMP binding in the enzyme preparations eluted by 0.1 M potassium phosphate (pH 7.0) from DEAE cellulose. The high-affinity cyclic GMP binding site (K_d about 44 · 10^?8 M belonged to some complex form of the protein kinase, as evidenced by the mutual inhibition of cyclic AMP binding and high affinity cyclic GMP binding. However, the high-affinity cyclic GMP binding site disappeared on Sephadex G-100 gel chromatography of the enzyme preparation, whereas the cyclic AMP binding activity was recovered quantitively as separate fractions. The low-affinity cyclic GMP binding site (K_d 2–5 · 10^?6 M) was demonstrated by the inhibitory effect of 10^?5 M cyclic GMP on cyclic AMP binding in each cyclic AMP binding fraction obtained by gel chromatography. However, cyclic AMP did not inhibit the binding of cyclic GMP to the low-affinity binding site.     

Amino acid-amino acid interactions studied by charge-transfer chromatography

The interaction between amino acids was studied by charge-transfer reversed-phase thin-layer chromatography. The dependence of the lipophilicity of Trp on the concentration of other amino acids in the eluent was considered to be linearly related to the strength of interaction. Arg, Asn, Glu, Met, Phe and Thr interacted with Trp; Ala, Gly and Ser showed no interaction. Stepwise regression analysis indicated that the pK value of the amino acid side-chain and the lipophilicity of the amino acid had the greatest impact on the interaction, suggesting the simultaneous presence of weak hydrophilic and hydrophobic bonding forces between amino acids. Sodium acetate in the eluent increased the interactive strength between Phe and Trp; acetic acid and sodium chloride did not influence the interaction significantly. No significant difference was found between the effects of l- and d-Asn.     

Effect of the aminoacid composition of model α-helical peptides on the physical properties of lipid bilayers and peptide conformation: a molecular dynamics simulation

The interaction of a model Lys flanked α-helical peptides K₂-X₂₄-K₂, (X = A,I,L,L+A,V) with lipid bilayers composed of dimyristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC) both, in a gel and in a liquid-crystalline state, has been studied by molecular dynamics simulations. It has been shown that these peptides cause disordering of the lipid bilayer in the gel state but only small changes have been monitored in a liquid-crystalline state. The peptides affect ordering of the surrounding lipids depending on the helix stability which is determined by amino acid side chains – their volume, shape, etc. We have shown that the helix does not keep the linear shape in all simulations but often bends or breaks. During some simulations with a very small difference between hydrophobic length of peptide and membrane thickness the peptide exhibits negligible tilt. At the same time changes in peptide conformations during simulations resulted in appearance of superhelix.     

Enhancing Diamond Color Center Fluorescence via Optimized Plasmonic Nanorod Configuration

Plasmonics - A novel numerical methodology has been developed, which makes possible to optimize arbitrary emitting dipole and plasmonic nano-resonator configuration with an arbitrary objective...     

Plant-derived smoke stimulates germination of four herbaceous species common in temperate regions of Europe

Germination responses to aerosol smoke and its aqueous solution (smoke–water) were studied in laboratory for six species common throughout temperate Europe: four annual weeds from the Brassicaceae family (Camelina microcarpa, Capsella bursa-pastoris, Descurainia sophia and Sisymbrium orientale), and two perennial Plantago species (P. lanceolata and P. media) inhabiting natural grasslands. It was hypothesized that smoke enhances germination for these species despite they are not fire-adapted. Both smoke treatments increased the final germination percentage for C. bursa-pastoris and D. sophia by fourfold to fivefold, for C. microcarpa by 73–224 % and for P. lanceolata by 26–41 % compared to the control. S. orientale and P. media showed high (>80 %) germination in the control with no significant response to smoke–water. These results confirm the occurrence of smoke-stimulated germination among species of the European natural flora inhabiting non-fire-prone habitats, suggest more successful seedling recruitment for smoke-responsive species with climate change-driven increase in fire frequency and can be used in the cultivation of the species or in weed control.     

Leaf water potential-leaf water deficit relationship for ten species of a semiarid grassland community

The relationship between water potential and relative water content (water content in percentage of full hydration) is a characteristic of plant tissues, that may vary with environmental conditions. It is used here to compare leaf water relations of ten species coexisting in a semiarid grassland community (Festucetum vaginatae danubiale) in Hungary. Three groups of species can be distinguished. In two of these leaf water potential changes only moderately with decreasing leaf water content. These are either short-lived, drought escaping spring plants relying on seasonally favourable water supply (group 1) or xerophytes with very deep root system having access to permanent water resources (group 2, only one species studied here). Xerophytes with moderately deep roots (group 3) display a rapid drop of leaf water potential with increasing leaf water deficit. This generates a steep water potential gradient in the soil-plant continuum that in turn enhances water uptake by roots. There is a positive correlation between the rate of water potential decline and degree of sclerophylly (proportion of dry material in the water-saturated leaf), and both variables show seasonal change in perennial species.