Frequency of multiple paternity in Myrmica scabrinodis from southern Poland

In haplodiploid insects that create social systems, more than one male may contribute to the progeny of a single female (polyandry). Little is known about the possible evolutionary benefits of multiple mating or the occurrence of this phenomenon across different species of Hymenoptera. Here we present our observations of polyandry in a Myrmica scabrinodis Nylander population from southern Poland. The estimated proportion of multiply mated queens was 0.71 and the average pedigree‐effective mate number was 1.45.     

Does experimentally simulated presence of a common cuckoo (Cuculus canorus) affect egg rejection and breeding success in the red-backed shrike (Lanius collurio)?

acta ethologica - Providing artificial eggs is a commonly used technique to understand brood parasitism, mainly by the common cuckoo (Cuculus canorus). However, the presence of a cuckoo egg in the...     

Protein Unfolding by Biological Unfoldases: Insights from Modeling

The molecular determinants of the high efficiency of biological machines like unfoldases (e.g., the proteasome) are not well understood. We propose a model to study protein translocation into the chamber of biological unfoldases represented as a funnel. It is argued that translocation is a much faster way of unfolding a protein than end-to-end stretching, especially in a low-force regime, because it allows for a conformational freedom while concentrating local tension on consecutive regions of a protein chain and preventing refolding. This results in a serial unfolding of the protein structures dominated by unzipping. Thus, pulling against the unfoldase pore is an efficient catalyst of the unfolding reaction. We also show that the presence of the funnel makes the tension along the backbone of the substrate protein nonuniform even when the protein gets unfolded. Hence, the stalling force measured by single-molecule force spectroscopy techniques may be smaller than the traction force of the unfoldase motor.     

Distribution pattern of the invasive alien plant Bunias orientalis in Rów Podtatrzański trench,north of the Tatra Mts,Poland

Bunias orientalis is an alien species that has spread greatly in recent decades in Central Europe. This coloniser is particularly well (pre)adapted to anthropogenic disturbances and human-mediated dispersal, allowing it to spread mainly along roads and railways. Here, its distribution and population structure is investigated for the sub-montane region located in the northern foothills of the Tatra Mts. Based on 70 phytosociological samples of invading vegetation, the relationships between B. orientalis cover and species diversity, together with the composition of vegetation, were analysed using regression analysis. Comparison of the current distribution of B. orientalis within the investigated area with published records indicates that the expansion rate of this alien species is not particularly high, despite its increased frequency in anthropogenic habitats and meadows. Meadows invaded by this species revealed that increased B. orientalis cover was accompanied by a significant reduction in the values of the Inverse Simpson diversity index and Pielou’s measure of evenness. Reduced diversity was caused by considerable decrease in cover by species of the Molinio-Arrhenatheretea class. However, for anthropogenic habitats, no statistically significant relationships were found to occur between the abundance of B. orientalis, species diversity and vegetation composition.     

Till evolution do us part: The diversity of symbiotic associations across populations of Philaenus spittlebugs

Symbiotic bacteria have played crucial roles in the evolution of sap-feeding insects and can strongly affect host function. However, their diversity and distribution within species are not well understood; we do not know to what extent environmental factors or associations with other species may affect microbial community profiles. We addressed this question in Philaenus spittlebugs by surveying both insect and bacterial marker gene amplicons across multiple host populations. Host mitochondrial sequence data confirmed morphology-based identification of six species and revealed two divergent clades of Philaenus spumarius. All of them hosted the primary symbiont Sulcia that was almost always accompanied by Sodalis. Interestingly, populations and individuals often differed in the presence of Sodalis sequence variants, suggestive of intra-genome 16S rRNA variant polymorphism combined with rapid genome evolution and/or recent additional infections or replacements of the co-primary symbiont. The prevalence of facultative endosymbionts, including Wolbachia, Rickettsia, and Spiroplasma, varied among populations. Notably, cytochrome I oxidase (COI) amplicon data also showed that nearly a quarter of P. spumarius were infected by parasitoid flies (Verralia aucta). One of the Wolbachia operational taxonomic units (OTUs) was exclusively present in Verralia-parasitized specimens, suggestive of parasitoids as their source and highlighting the utility of host gene amplicon sequencing in microbiome studies.     

Characterization of the effectors required for stable inheritance of Streptococcus pyogenes pSM19035-derived plasmids in Bacillus subtilis

The low-copy-number and broad-host-range pSM19035-derived plasmid pBT233 is stably inherited in Bacillus subtilis cells. Two distinct regions, segA and segB, enhance the segregational stability of the plasmid. Both regions function in a replicon-independent manner. The maximization of random plasmid segregation is accomplished by the recombination proficiency of the host or the presence of the pBT233 segA region. The segA region contains two open reading frames (or?) [α and β]. Inactivation or deletion of or?β results in SegA^? plasmids. Better than random segregation requires an active segB region. The segB region contains two or?s (or?? and or?ζ). Inactivation of either of the orfs does not lead to an increase in cell death, but or?ζ^? plasmids are randomly segregated. These results suggest that pBT233 stabilization relies on a complex system involving resolution of plasmid oligomers (segA) and on the function(s) encoded by the segB region.     

Endophytic yeast protect plants against metal toxicity by inhibiting plant metal uptake through an ethylene-dependent mechanism

Toxic metal pollution requires significant adjustments in plant metabolism. Here, we show that the plant microbiota plays an important role in this process. The endophytic Sporobolomyces ruberrimus isolated from a serpentine population of Arabidopsis arenosa protected plants against excess metals. Coculture with its native host and Arabidopsis thaliana inhibited Fe and Ni uptake. It had no effect on host Zn and Cd uptake. Fe uptake inhibition was confirmed in wheat and rape. Our investigations show that, for the metal inhibitory effect, the interference of microorganisms in plant ethylene homeostasis is necessary. Application of an ethylene synthesis inhibitor, as well as loss-of-function mutations in canonical ethylene signalling genes, prevented metal uptake inhibition by the fungus. Coculture with S. ruberrimus significantly changed the expression of Fe homeostasis genes: IRT1, OPT3, OPT6, bHLH38 and bHLH39 in wild-type (WT) A. thaliana. The expression pattern of these genes in WT plants and in the ethylene signalling defective mutants significantly differed and coincided with the plant accumulation phenotype. Most notably, down-regulation of the expression of IRT1 solely in WT was necessary for the inhibition of metal uptake in plants. This study shows that microorganisms optimize plant Fe and Ni uptake by fine-tuning plant metal homeostasis.     

Plasma trace element (Se,Zn, Cu) concentrations in maternal and umbilical cord blood in Poland

Selenium (Se), copper (Cu), and zinc (Zn) concentrations were determined in plasma of 64 mothers at delivery, 58 nonpregnant women, 64 neonates, and 12 infants, aged 2–12 mo. Se and Zn concentrations in mothers at delivery were significantly lower, and Cu higher than in nonpregnant women. Mean Se and Cu concentrations in newborns were statistically lower than those in mothers at delivery, and Zn and Cu concentrations in preterm infants (n=13) were significantly higher than in fullterm infants (n=51). Maternal parity had no significant influence on the distribution of plasma trace element levels. No significant differences were observed in Se and Zn levels in maternal and cord blood plasma according to birth weight, contrary to maternal Cu concentration. Significant correlations were found between maternal and cord blood Se content, and between maternal plasma Cu concentration and birth weight of neonates.     

Circular Dichroism Studies of the Interaction of Tat Analogues Substituted in the Arg52 Position with TAR RNA HIV-1

The Tat wild-type fragment of sequence Arg⁴⁹-Lys-Lys-Arg⁵²-Arg-Gln-Arg-Arg-Arg⁵⁷-NH₂ (labelled as Tat1) and three analogues of this fragment with the substitution Arg⁵² → D-Arg⁵² (labelled as Tat2) or L-citrulline (Cit) (labelled as Tat3) or L-ornithine (Orn) (labelled as Tat4) were synthesized to study Tat-TAR RNA HIV-1 (27-nucleotide fragment of sequence 5′-AGAUCUGAGCCUGGAGCUCUCU-3′) interactions by circular dichroism. α-helical structure was the most readily adopted by the Tat3 analogue with Arg⁵² → Cit substitution. All the peptides investigated caused conformational changes in the TAR structure. The most dramatic changes were observed for the Tat2-TAR complex.     

Effect of phenoxyalkanoic acid herbicides on the fermentative production of l-lysine

Summary The effect of the herbicides MCPA, MCPB, mecoprop, dichlorprop, 2,4-D, 2,4-DB, and 2,4,5-T on l-lysine fermentation was investigated using a lysine-producing mutant of Corynebacterium glutamicum. Stimulation of l-lysine production by 6% to 36% was observed in shaken flask experiments when the test herbicides were added at a concentration of 5 · 10^-4 M to growing cultures after 24 h of cultivation. The most effective stimulators were MCPA, mecoprop and dichlorprop.Detailed studies of the effect of MCPA (5 · 10^-6 M to 5 · 10^-3 M) showed that the degree of stimulation depended on medium composition and aeration. In the synthetic medium, maximum production of 50 g · l^-1 lys · HCl occurred at 5 · 10^-4 M MCPA and an oxygen transfer rate (OTR) of 1.97 g O₂ · l^-1 · h^-1, while 61.7 g · l^-1 of lys · HCL was formed at 5 · 10^-3 M MCPA and an OTR of 3.75 g O₂ · l^-1 · h^-1. In the amino-nitrogen rich medium, maximum production of 42 g · l^-1 lys · HCl was observed at 5 · 10^-6 M MCPA and an oxygen transfer rate of 1.5 g O₂ · l^-1 · h^-1. Results from batch l-lysine fermentation in a fermenter showed similar stimulatory effects, with an optimal concentration of MCPA for l-lysine production of 5 · 10^-5 M. Without herbicide addition, the test strain produced 16.25 g · l^-1 of product and with addition of 5 · 10^-5 M MCPA, the same strain produced 52.1 g · l^-1 lys · HCl after 72 h of fermentation.Abbreviations MCPA 2-methyl-4-chlorophenoxyacetic acid - MCPB 2-methyl-4-chlorophenoxybutyric acid - mecoprop 2-methyl-4-chlorophenoxypropionic acid - dichlorprop 2,4-dichlorophenoxypropionic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - 2,4-DB 2,4-dichlorophenoxybutyric acid - 2,4,5-T 2,4,5-trichlorophenoxyacetic acid