The wing base of the palaeodictyopteran genus Dunbaria Tillyard: Where are we now?

The structure of insect wing articulation is considered as reliable source of high level characters for phylogenetic analyses. However, the correct identification of homologous structures among the main groups of Pterygota is a hotly debated issue. Therefore, the reconstruction of the wing bases in Paleozoic extinct relatives is of great interest, but at the same time it should be treated with extreme caution due to distortions caused by taphonomic effects. The present study is focused on the wing base in Dunbaria (Spilapteridae). The articulation in Dunbaria quinquefasciata is mainly formed by a prominent upright axillary plate while the humeral plate is markedly reduced. Due to unique preservation of surface relief of the axillary plate, its composition shows a detailed pattern of three fused axillary sclerites and presumable position of the sclerite 3Ax. The obtained structures were compared among Spilapteridae and to other palaeodictyopterans Ostrava nigra (Homoiopteridae) and Namuroningxia elegans (Namuroningxiidae). The comparative study uncovered two patterns of 3Ax in Dunbaria and Namuroningxia, which correspond to their different suprafamilial classification. In contrast to previous studies these new results reveal the homologous structural elements in the wing base between Paleozoic Palaeodictyoptera and their extant relatives of Ephemeroptera, Odonata and Neoptera.     

Isolation of chlorophylls and carotenoids from freshwater algae using different extraction methods

Usually marine algae are an excellent source of pigments for different commercial sectors. Freshwater macroalgae can be exploited as a good source of biologically active compounds provided an appropriate extraction method is developed. The efficiency of four methods, like microwave‐assisted (MAE), ultrasound‐assisted extraction (UAE), supercritical fluid extraction (SFE) with ethanol as a co‐solvent, as well as conventional Soxhlet extraction were studied in the same conditions (time, solvent and temperature) for the recovery of chlorophylls and carotenoids from three freshwater green algae species: Cladophora glomerata, Cladophora rivularis and Ulva flexuosa. UV‐Vis spectrophotometry was used to determine chlorophyll a, chlorophyll b and total carotenoid content in obtained extracts. The results of this study showed that the advantages of novel extraction techniques (MAE and UAE) include higher yield and, in consequence, lower costs compared to traditional solvent extraction techniques. These methods were much more efficient in freshwater green algae pigment recovery than the classic Soxhlet extraction as well as SFE.     

Protein tyrosine phosphatase gene expression analysis in Swiss 3T3 fibroblasts

The aim of this study was to identify protein tyrosine phosphatases (PTPs) expressed in Swiss 3T3 fibroblasts and to examine their expression levels as well as to characterize quantitative aspects of RT-PCR based on degenerate deoxyoligonucleotides. By using an RT-PCR assay based on degenerate deoxyoligonucleotide primers, expression of mRNAs for two cytoplasmic- and six transmembrane-type PTPs in Swiss 3T3 cells was detected. The sequences of two of them are new. Among nine analyzed PTPs expressed to widely varied extends, only three have mRNA levels high enough to be seen on Northern blots with 10 µg of total RNA per lane. The frequencies with which the examined PTPs are represented among the PCR amplification products, correlate stronger with the primer fidelity, defined as the number of mismatches between the primer- and the cDNA target-sequences, rather than with the PTP expression levels. In conclusion, an RT-PCR assay based on degenerate primers can be successfully used to sample the expressed PTPs and to identify new members of this gene family. However, reliable quantification of their mRNA levels can only be achieved using the classical approaches, like Northern, RNase protection assay or non-degenerate quantitative RT-PCR.     

Invasive round goby Neogobius melanostomus has sex‐dependent locomotor activity and is under‐represented in catches from passive fishing gear compared with seine catches

The higher proportion of males of the invasive round goby Neogobius melanostomus in samples from two activity selective passive fishing gears compared with one activity non‐selective fishing gear in three Dutch lakes is related to higher male locomotory activity and is a sex‐dependent trait. This difference in activity reflects the different ecology of male and female N. melanostomus.     

Timber stacks: potential ecological traps for an endangered saproxylic beetle,the Rosalia longicorn <Emphasis Type="Italic">Rosalia alpina</Emphasis>

Ecological traps are serious, anthropogenic threats to animal populations. However, in certain cases it is difficult to determine whether they really act in the expected manner. This applies to the harmful effects of beech timber stacked in forests on the endangered saproxylic beetle Rosalia longicorn Rosalia alpina, which have been mentioned in numerous scientific articles, conservation action plans and similar publications. The aim of this paper is to determine whether beech timber stacks meet the criteria of an ecological trap for the Rosalia longicorn. Two basic criteria of such a trap are analysed: the attractiveness of timber stacks and the impossibility of complete larval development. The results show that beech timber stacks are highly attractive to Rosalia longicorn imagines. Moreover, the time during which the timber is stacked is shown to be significantly shorter than the species’ larval development period. These results suggest that timber stacks can be treated as operative ecological traps for the Rosalia longicorn, even though the extent of their influence on the demographic parameters of this beetle’s population has not been estimated. Forest management practices, i.e. increasing amounts and shifts in timing of wood storage, could intensify this threat.     

Expression and activity of cGMP-dependent phosphodiesterases is up-regulated by lipopolysaccharide (LPS) in rat peritoneal macrophages

It has been shown that cyclic GMP (cGMP) modulates the inflammatory responses of macrophages, but the underlying molecular mechanisms are still poorly understood. Looking for proteins potentially regulated by cGMP in rat peritoneal macrophages (PMs), in this study we analyzed expression and activity of cGMP-hydrolyzing and cGMP-regulated phosphodiesterases (PDEs). It was found that freshly isolated peritoneal exudate macrophages (PEMs) express enzymes belonging to families PDE1-3, PDE5, PDE10, and PDE11. Analysis of substrate specificity, sensitivity to inhibitors, and subcellular localization showed that PDE2 and PDE3 are the main cGMP-regulated PDE isoforms in PEMs. The profile of PDE expression was altered by maintaining PEMs in culture and treatment with bacterial endotoxin (LPS). After 24 h culture, PDE5 was not present and the levels of PDE2, PDE3, and PDE11 were markedly decreased. However, their expression and activity was recovered after treatment of cultured cells with LPS. A similar pattern of changes was observed for the expression of TNFalpha, but not for guanylyl cyclase A (GC-A). LPS up-regulated PDE expression also in resident peritoneal macrophages (RPMs), although not all PDEs present in PEMs were detected in RPMs. Taken together, our results show that in rat PMs expression of cGMP-dependent PDEs positively correlates with the activation state of cells. Moreover, the fact that most of these PDEs hydrolyze also cAMP indicates that cGMP can play a role of potent regulator of cAMP signaling in macrophages.     

Acute impact of blood flow restriction on strength-endurance performance during the bench press exercise

The main goal of the present study was to evaluate the acute effects of blood flow restriction (BFR) at 70% of full arterial occlusion pressure on strength-endurance performance during the bench press exercise. The study included 14 strength-trained male subjects (age = 25.6 ± 4.1 years; body mass = 81.7 ± 10.8 kg; bench press 1 repetition maximum (1RM) = 130.0 ± 22.1 kg), experienced in resistance training (3.9 ± 2.4 years). During the experimental sessions in a randomized crossover design, the subjects performed three sets of the bench press at 80% 1RM performed to failure with two different conditions: without BFR (CON); and with BFR (BFR). Friedman’s test showed significant differences between BFR and CON conditions for the number of repetitions performed (p < 0.001); for peak bar velocity (p < 0.001) and for mean bar velocity (p < 0.001). The pairwise comparisons showed a significant decrease for peak bar velocity and mean bar velocity in individual Set 1 for BFR when compared to CON conditions (p = 0.01 for both). The two-way repeated measures ANOVA showed a significant main effect for the time under tension (p = 0.02). A post-hoc comparisons for the main effect showed a significant increase in time under tension for BFR when compared to CON (p = 0.02). The results of the presented study indicate that BFR used during strength-endurance exercise generally does not decrease the level of endurance performance, while it causes a drop in bar velocity.     

Codiversification of gastrointestinal microbiota and phylogeny in passerines is not explained by ecological divergence

Vertebrate gut microbiota (GM) is comprised of a taxonomically diverse consortium of symbiotic and commensal microorganisms that have a pronounced effect on host physiology, immune system function and health status. Despite much research on interactions between hosts and their GM, the factors affecting inter‐ and intraspecific GM variation in wild populations are still poorly known. We analysed data on faecal microbiota composition in 51 passerine species (319 individuals) using Illumina MiSeq sequencing of bacterial 16S rRNA (V3–V4 variable region). Despite pronounced interindividual variation, GM composition exhibited significant differences at the interspecific level, accounting for approximately 20%–30% of total GM variation. We also observed a significant correlation between GM composition divergence and host's phylogenetic divergence, with strength of correlation higher than that of GM vs. ecological or life history traits and geographic variation. The effect of host's phylogeny on GM composition was significant, even after statistical control for these confounding factors. Hence, our data do not support codiversification of GM and passerine phylogeny solely as a by‐product of their ecological divergence. Furthermore, our findings do not support that GM vs. host's phylogeny codiversification is driven primarily through trans‐generational GM transfer as the GM vs. phylogeny correlation does not increase with higher sequence similarity used when delimiting operational taxonomic units. Instead, we hypothesize that the GM vs. phylogeny correlation may arise as a consequence of interspecific divergence of genes that directly or indirectly modulate composition of GM.     

Synthesis and cytotoxic activity of gamma-aryl substituted alpha-alkylidene-gamma-lactones and alpha-alkylidene-gamma-lactams

A series of 5-aryl-3-alkylidenedihydrofuran-2(3H)-ones 6a–g″ and 11a,b as well as 5-aryl-3-methylidenepyrrolidin-2-ones 10a–c and 12 were synthesized starting from 4-aryl-2-diethoxyphosphoryl-4-oxobutanoates 3a–g. Reaction sequence includes reduction or reductive amination of the carbonyl group, lactonization or lactamization step and finally the Horner–Wadsworth–Emmons olefination of aldehydes using thus obtained 5-aryl-3-diethoxyphosphoryl-3,4-dihydrofuran-2(5H)-ones 5a–g″ or 5-aryl-3-diethoxyphosphorylpyrrolidin-2-ones 9a–c. Furanones 6 and 11, as well as pyrrolidinones 10 and 12, were evaluated in vitro against mouse leukemia cell line L-1210 and two human leukemia cell lines HL-60 and NALM-6. Several of the obtained furanones proved to be very potent against all three cell lines with IC₅₀ values lower than 6 μM. Structure–activity relationships of these compounds, as well as 5-alkyl or 5-arylmethyl-3-methylidenedihydrofuran-2(3H)-ones 13a–e, previously obtained in our laboratory, are discussed.