Comparative analyses of song complexity and song-control nuclei in fourteen oscine species

Most studies on the relationship between measures of song behavior and the sizes of song control nuclei have focused on one or two oscine species, and often show inconsistent results. To address this issue, we first measured four variables for song complexity, i.e., song repertoire size, syllable repertoire size, the mean number of syllables per phrase (MNS) and the number of syllables in the longest phrase (NSLP), and the sizes of three song control nuclei, i.e., HVC, RA (the robust nucleus of the arcopallium), and Area X in 14 oscine species from eight families. To tackle the problem of statistical non-independence that probably existed among the closely related species, we reconstructed the phylogeny of the species studied using mitochondrial cytochrome b DNA sequences from GenBank. By using the methods adopted in most previous reports, we tested the relationship between song complexity and the sizes of the song control nuclei. We found that: 1) the absolute sizes of RA and Area X, but not of HVC, were positively correlated to the three measures of song complexity, but that only the residual size of RA in regard to telencephalon size was significantly correlated to the song measures; 2) independent contrasts analysis showed RA and Area X to be significantly associated with NSLP. Our results indicated that the relationship between song behavior and its neural structures varied among song nuclei, suggesting that each song control nucleus may play a different role in song behavior.     

Genetic interaction of Gsc and Dkk1 in head morphogenesis of the mouse

Mouse embryos lacking Gsc and Dkk1 function display severe deficiencies in craniofacial structures which are not found in either Dkk1 homozygous null or Gsc homozygous null mutant embryos. Loss of Gsc has a dosage-related effect on the severity of head truncation phenotype in Dkk1 heterozygous embryos. The synergistic effect of these mutations in enhancing head truncation provides direct evidence of a genetic interaction between Gsc and Dkk1, which display overlapping expression in the prechordal mesoderm. In the absence of Gsc activity, the expression of Dkk1, WNT genes and a transgenic reporter for WNT signalling are altered. Our results show that Gsc and Dkk1 functions are non-redundant in the anterior mesendoderm for normal anterior development and Gsc may influence Wnt signalling as a negative regulator.     

Freezing effect on chirality generation of DL-alanine-N-carboxy-anhydride oligomerization in aqueous solution

This article is concerned with a study of the role of ice in the synthesis of oligopeptides containing L- or D-enantiomeric excess (ee) from racemic alanine. With this aim, the oligomerization of DL-alanine-N-carboxyanhydride was investigated by keeping this activated derivative in liquid (+22 degrees C) or frozen (-20 degrees C) aqueous solutions for 30 days. The aqueous solution of the peptide mixtures were gel-filtered and the aliquots of the fractions were completely hydrolyzed to alanine monomers. These monomers were then derivatized with 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide (Marfey's reagent) and analyzed by RP-HPLC to reveal the occasional enantiomeric excess of L- or D-Ala. The mass spectrometry of the gel-filtered fractions pointed to open-chain peptide mixtures together with a slight amount of cyclic ones, where the residue numbers ranged between 5-8. Our studies indicated that an enantiomeric excess of L- or D-Ala appeared in some oligopeptide fractions. Their excesses were significantly larger in the frozen than liquid solution. Speculations are made as concerns the implications of our findings in the events of prebiotic chemistry.     

The Blomia tropicalis allergens

Blomia tropicalis allergens are the most important mite allergens in tropical regions. Most of them only have 30-40% sequence identity with their Dermatophagoides counterparts and they share low IgE cross reactivity and exhibit different immunobiology. Unlike the pyroglyphid counterparts, Blo t 5 is the major allergen whereas Blo t 1 only has modest allergenicity.     

Characterization of a petunia acetyltransferase involved in the biosynthesis of the floral volatile isoeugenol

Petunia flower petals emit large amounts of isoeugenol, which has been shown to be synthesized by isoeugenol synthase (PhIGS1) from an ester of coniferyl alcohol, hypothesized to be coniferyl acetate. This paper describes the identification and characterization of a novel petunia gene encoding an enzyme belonging to the BAHD acyltransferase family whose expression correlates with isoeugenol biosynthesis. RNAi suppression of this gene results in inhibition of isoeugenol biosynthesis. Biochemical characterization of the protein encoded by this gene showed that it has acetyltransferase activity and is most efficient with coniferyl alcohol among the alcohol substrates tested. Overall, these data support the conclusion that coniferyl acetate is the substrate of isoeugenol synthase.     

Spatial pattern of water bugs (Nepomorpha,Gerromorpha) at different scales in the Szigetköz (Hungary)

In 2003, 26 Heteroptera species (16 aquatic and 10 semiaquatic) were collected from 53 sampling sites in the Szigetköz region in Hungary. Hyocoris cimicoides and Gerris argentatus were the most frequent aquatic and semiaquatic species, respectively. Large differences both in the species number and species composition were observed among the different flood-prevention areas, arm systems and habitats. Strong negative correlation was found between the average number of aquatic species and current velocity, and a strong positive correlation between the average number of aquatic and semiaquatic species and macrophyte density. From a faunistic point of view, the marsh at Arak is the most interesting and valuable site.     

Critical role of DNA checkpoints in mediating genotoxic-stress-induced filamentous growth in Candida albicans

The polymorphic fungus Candida albicans switches from yeast to filamentous growth in response to a range of genotoxic insults, including inhibition of DNA synthesis by hydroxyurea (HU) or aphidicolin (AC), depletion of the ribonucleotide-reductase subunit Rnr2p, and DNA damage induced by methylmethane sulfonate (MMS) or UV light (UV). Deleting RAD53, which encodes a downstream effector kinase for both the DNA-replication and DNA-damage checkpoint pathways, completely abolished the filamentous growth caused by all the genotoxins tested. Deleting RAD9, which encodes a signal transducer of the DNA-damage checkpoint, specifically blocked the filamentous growth induced by MMS or UV but not that induced by HU or AC. Deleting MRC1, the counterpart of RAD9 in the DNA-replication checkpoint, impaired DNA synthesis and caused cell elongation even in the absence of external genotoxic insults. Together, the results indicate that the DNA-replication/damage checkpoints are critically required for the induction of filamentous growth by genotoxic stress. In addition, either of two mutations in the FHA1 domain of Rad53p, G65A, and N104A, nearly completely blocked the filamentous-growth response but had no significant deleterious effect on cell-cycle arrest. These results suggest that the FHA domain, known for its ability to bind phosphopeptides, has an important role in mediating genotoxic-stress-induced filamentous growth and that such growth is a specific, Rad53p-regulated cellular response in C. albicans.     

Biodiversity restoration of formerly extracted raised bogs: vegetation succession and recovery of other trophic groups

Central European raised bogs are unique and fragile ecosystems inhabited by specialists of higher plants, fungi, and insects. Many of these ecosystems have suffered and are still suffering due to peat harvesting and drainage. The respective specialists, so-called tyrphobionts, and their abundance can serve as good indicators of restoration processes after the disturbance. Various taxonomic groups may differ in the response to the processes. This study shows successional trends in two disturbed raised bogs compared to adjoining undisturbed reference raised bogs. During the growing season of 2019 we compared species richness of successional stages with reference sites for the following five groups of organisms: vascular plants, mosses, fungi, butterflies, and moths. After three decades of spontaneous succession, the species composition did not reach the reference site for any taxonomic group. Instead an alternative, near-natural woodland developed. The different groups of organisms exhibited very similar trends in species richness and participation of tyrphobionts. About half of these specialists occurring at the reference sites were able to colonise the disturbed sites, but mostly in low quantity. Water table and pH appeared significant environmental variables. It seems that habitat limitations play a more important role than dispersal limitations in this restoration process. More successful restoration might be possible by substantially increasing the water table in the disturbed raised bogs.