Spreading free-riding snow sports represent a novel serious threat for wildlife

Stress generated by humans on wildlife by continuous development of outdoor recreational activities is of increasing concern for biodiversity conservation. Human disturbance often adds to other negative impact factors affecting the dynamics of vulnerable populations. It is not known to which extent the rapidly spreading free-riding snow sports actually elicit detrimental stress (allostatic overload) upon wildlife, nor what the potential associated fitness and survival costs are. Using a non-invasive technique, we evaluated the physiological stress response induced by free-riding snow sports on a declining bird species of Alpine ecosystems. The results of a field experiment in which radiomonitored black grouse (Tetrao tetrix) were actively flushed from their snow burrows once a day during four consecutive days showed an increase in the concentration of faecal stress hormone (corticosterone) metabolites after disturbance. A large-scale comparative analysis across the southwestern Swiss Alps indicated that birds had higher levels of these metabolites in human-disturbed versus undisturbed habitats. Disturbance by snow sport free-riders appears to elevate stress, which potentially represents a new serious threat for wildlife. The fitness and survival costs of allostatic adjustments have yet to be estimated.     

Variability of latewood-widths and -stable isotope ratios in a sessile oak tree (Quercus petraea (Matt.) Liebl.)

Axial variation of latewood-widths and -stable isotopes (δ¹³C and δ¹⁸O) of a single sessile oak tree (Quercus petraea (Matt.) Liebl.) was analyzed. The influence of sampling height was found to be weak for both, latewood-widths and -stable isotopes in the latewood. The observed trends with stem-height show clearly that possible effects due to cambial aging are overrated by annual effects. In addition, relations between samples from different stem-heights are strong for identical calendar years while they are poor for identical cambial age. This indicates that samples from both, living trees and historical wood can be taken from any height position of a trunk or beam as long they are free from anatomical abnormities. Simple correlation and Gleichläufigkeit were used for validation.     

Enhanced Cutinase-Catalyzed Hydrolysis of Polyethylene Terephthalate by Covalent Fusion to Hydrophobins

Cutinases have shown potential for hydrolysis of the recalcitrant synthetic polymer polyethylene terephthalate (PET). We have shown previously that the rate of this hydrolysis can be enhanced by the addition of hydrophobins, small fungal proteins that can alter the physicochemical properties of surfaces. Here we have investigated whether the PET-hydrolyzing activity of a bacterial cutinase from Thermobifida cellulosilytica (Thc_Cut1) would be further enhanced by fusion to one of three Trichoderma hydrophobins, i.e., the class II hydrophobins HFB4 and HFB7 and the pseudo-class I hydrophobin HFB9b. The fusion enzymes exhibited decreased k_cat values on soluble substrates (p-nitrophenyl acetate and p-nitrophenyl butyrate) and strongly decreased the hydrophilicity of glass but caused only small changes in the hydrophobicity of PET. When the enzyme was fused to HFB4 or HFB7, the hydrolysis of PET was enhanced >16-fold over the level with the free enzyme, while a mixture of the enzyme and the hydrophobins led only to a 4-fold increase at most. Fusion with the non-class II hydrophobin HFB9b did not increase the rate of hydrolysis over that of the enzyme-hydrophobin mixture, but HFB9b performed best when PET was preincubated with the hydrophobins before enzyme treatment. The pattern of hydrolysis by the fusion enzymes differed from that of Thc_Cut1 as the concentration of the product mono(2-hydroxyethyl) terephthalate relative to that of the main product, terephthalic acid, increased. Small-angle X-ray scattering (SAXS) analysis revealed an increased scattering contrast of the fusion proteins over that of the free proteins, suggesting a change in conformation or enhanced protein aggregation. Our data show that the level of hydrolysis of PET by cutinase can be significantly increased by fusion to hydrophobins. The data further suggest that this likely involves binding of the hydrophobins to the cutinase and changes in the conformation of its active center.     

An extended combinatorial 15N, 13Cα, and $$ ^{13} {\text{C}}^{\prime } $$ labeling approach to protein backbone resonance assignment

Solution NMR studies of α-helical membrane proteins are often complicated by severe spectral crowding. In addition, hydrophobic environments like detergent micelles, isotropic bicelles or nanodiscs lead to considerably reduced molecular tumbling rates which translates into line-broadening and low sensitivity. Both difficulties can be addressed by selective isotope labeling methods. In this publication, we propose a combinatorial protocol that utilizes four different classes of labeled amino acids, in which the three backbone heteronuclei (amide nitrogen, α-carbon and carbonyl carbon) are enriched in ¹⁵N or ¹³C isotopes individually as well as simultaneously. This results in eight different combinations of dipeptides giving rise to cross peaks in ¹H–¹⁵N correlated spectra. Their differentiation is achieved by recording a series of HN-detected 2D triple-resonance spectra. The utility of this new scheme is demonstrated with a homodimeric 142-residue membrane protein in DHPC micelles. Restricting the number of selectively labeled samples to three allowed the identification of the amino-acid type for 77 % and provided sequential information for 47 % of its residues. This enabled us to complete the backbone resonance assignment of the uniformly labeled protein merely with the help of a 3D HNCA spectrum, which can be collected with reasonable sensitivity even for relatively large, non-deuterated proteins.     

Phylogenetic systematics of leaffishes (Teleostei: Polycentridae,Nandidae)

The Asian (nandid) and Afro‐Neotropical (polycentrid) leaffishes represent two superficially similar, but historically poorly diagnosed families – a situation resulting in a convoluted systematic history. Here, and including for the first time in a molecular study all leaffish genera, we generate a hypothesis of the phylogenetic history of both groups. We analyse a multilocus molecular data set encompassing 257 acanthomorph taxa, carry out a survey and assessment of selected osteological characters for the polycentrid leaffishes and also provide a reanalysis of previously published morphological data. Our results confirm: (1) that the Polycentridae and Nandidae are only remotely related, and hence, the classic leaffishes are diphyletic; (2) that the Polycentridae is monophyletic, with new skeletal synapomorphies being congruent with molecular data in placing the enigmatic Afronandus – a taxon that thus far has never been included in any molecular study – as sistergroup to the remaining genera; (3) the monophyly of the Nandidae + Badidae and their inclusion into a larger monophyletic group – along with the Pristolepididae, Anabantoidei and Channoidei – comprising the Labyrinthici sensu Rosen & Patterson. We also review the morphological and molecular evidence for both the conflicting placement of Pristolepis and the putative sistergroup relationship between the labyrinth fishes (Anabantoidei) and snakeheads (Channoidei).     

Tandem quadruplication of HMA4 in the zinc (Zn) and cadmium (Cd) hyperaccumulator Noccaea caerulescens

Zinc (Zn) and cadmium (Cd) hyperaccumulation may have evolved twice in the Brassicaceae, in Arabidopsis halleri and in the Noccaea genus. Tandem gene duplication and deregulated expression of the Zn transporter, HMA4, has previously been linked to Zn/Cd hyperaccumulation in A. halleri. Here, we tested the hypothesis that tandem duplication and deregulation of HMA4 expression also occurs in Noccaea.A Noccaea caerulescens genomic library was generated, containing 36,864 fosmid pCC1FOS™ clones with insert sizes ∼20–40 kbp, and screened with a PCR-generated HMA4 genomic probe. Gene copy number within the genome was estimated through DNA fingerprinting and pooled fosmid pyrosequencing. Gene copy numbers within individual clones was determined by PCR analyses with novel locus specific primers. Entire fosmids were then sequenced individually and reads equivalent to 20-fold coverage were assembled to generate complete whole contigs.Four tandem HMA4 repeats were identified in a contiguous sequence of 101,480 bp based on sequence overlap identities. These were flanked by regions syntenous with up and downstream regions of AtHMA4 in Arabidopsis thaliana. Promoter-reporter β-glucuronidase (GUS) fusion analysis of a NcHMA4 in A. thaliana revealed deregulated expression in roots and shoots, analogous to AhHMA4 promoters, but distinct from AtHMA4 expression which localised to the root vascular tissue.This remarkable consistency in tandem duplication and deregulated expression of metal transport genes between N. caerulescens and A. halleri, which last shared a common ancestor >40 mya, provides intriguing evidence that parallel evolutionary pathways may underlie Zn/Cd hyperaccumulation in Brassicaceae.