Dialects of an invasive songbird are preserved in its invaded but not native source range

Biological invasions are not only events with substantial environmental and socioeconomic impacts but are also interesting natural experiments, allowing the study of phenomena such as the cultural evolution of bird song following introduction. We took an excellent opportunity to compare the distribution of dialects of the yellowhammer Emberiza citrinella, a small Eurasian passerine, in its native source region (Great Britain) and invaded range (New Zealand) more than hundred years after relocation. Recent field recordings (including those provided by volunteers within a citizen science project) were complemented by those from archives, each assigned to appropriate dialect by visual inspection of a sonogram, and the resulting spatial patterns of dialect distribution were interpreted using historical data on the yellowhammer invasion. The two countries differ markedly in the composition and distribution of dialects. New Zealand populations sing a greater number of different dialects, seven in total, five of which were not detected in the current British population, but have been reported by previous studies from the continental Europe. Two identified localities of capture (Brighton, Sussex, UK) and release (Dunedin, Otago, NZ) differ even more strikingly, having no dialects in common. The largely sedentary nature of yellowhammers allows for two mutually exclusive explanations for European dialects being detected in New Zealand but not in Great Britain: 1) the corresponding song types have emerged de novo in New Zealand, through convergent cultural evolution; 2) the dialects have disappeared from Great Britain, while being preserved in New Zealand. Indirect evidence from the widespread occurrence of these dialects in continental Europe and the reported stability of yellowhammer song, supports the latter explanation. We suggest that the yellowhammer dialect system is an avian equivalent of a phenomenon already noted in human languages, in which ancient words or structures are retained in expatriate communities.     

Around the Mediterranean: an extreme example of loop migration in a long‐distance migratory passerine

An important issue in migration research is how small‐bodied passerines pass over vast geographical barriers; in European–African avian migration, these are represented by the Mediterranean Sea and the Sahara Desert. Eastern (passing eastern Mediterranean), central (passing Apennine Peninsula) and western (via western Mediterranean) major migration flyways are distinguished for European migratory birds. The autumn and spring migration routes may differ (loop migration) and there could be a certain level of individual flexibility in how individuals navigate themselves during a single migration cycle. We used light‐level loggers to map migration routes of barn swallows Hirundo rustica breeding in the centre of a wide putative contact zone between the northeastern and southernwestern European populations that differ in migration flyways utilised and wintering grounds. Our data documented high variation in migration patterns and wintering sites of tracked birds (n = 19 individuals) from a single breeding colony, with evidence for loop migration in all but one of the tracked swallows. In general, two migratory strategies were distinguished. In the first, birds wintering in a belt stretching from southcentral to southern Africa that used an eastern route for both the spring and autumn migration, then shifted their spring migration eastwards (anti‐clockwise loops, n = 12). In the second, birds used an eastern or central route to their wintering grounds in central Africa, shifting the spring migration route westward (clockwise loops, n = 7). In addition, we observed an extremely wide clockwise loop migration encompassing the entire Mediterranean, with one individual utilising both the eastern (autumn) and western (spring) migratory flyway during a single annual migration cycle. Further investigation is needed to ascertain whether clockwise migratory loops encircling the entire Mediterranean also occur other small long‐distance passerine species.     

Efficient screening of potential cellulases and hemicellulases produced by <Emphasis Type="Italic">Bosea</Emphasis> sp. FBZP-16 using the combination of enzyme assays and genome analysis

Identification of bacteria that produce carbohydrolytic enzymes is extremely important given the increased demand for these enzymes in many industries. Twenty lignocellulose-degrading bacterial isolates from Algerian compost and different soils were screened for their potential to produce different enzymes involved in biomass deconstruction. Based on 16S rRNA gene sequencing, the isolates belonged to Proteobacteria and Actinobacteria. Differences among species were reflected both as the presence/absence of enzymes or at the level of enzyme activity. Among the most active species, Bosea sp. FBZP-16 demonstrated cellulolytic activity on both amorphous cellulose (CMC) and complex lignocellulose (wheat straw) and was selected for whole-genomic sequencing. The genome sequencing revealed the presence of a complex enzymatic machinery required for organic matter decomposition. Analysis of the enzyme-encoding genes indicated that multiple genes for endoglucanase, xylanase, β-glucosidase and β-mannosidase are present in the genome with enzyme activities displayed by the bacterium, while other enzymes, such as certain cellobiohydrolases, were not detected at the genomic level. This indicates that a combination of functional screening of bacterial cultures with the use of genome-derived information is important for the prediction of potential enzyme production. These results provide insight into their possible exploitation for the production of fuels and chemicals derived from plant biomass.     

The genetic control of natural killer cell activity and its association with in vivo resistance against a moloney lymphoma isograft

Spleens of normal young mice of certain strains contain lymphocytes that can kill strain A-derived YAC-1 lymphoma cells in a⁵¹Cr release cytotoxic assay in vitro. We have previously classified mouse genotypes as high or low reactors, according to their responses in this test. In vivo resistance to small numbers of YAC ascites lymphoma cells is correlated with in vitro cytolytic activity. In vitro and in vivo tests were carried out on the same individual (A x C57BL)F₁ x A backcross mice. Natural in vitro killer cell activity appeared to be under polygenic control, including a strong H-2-linked factor. No linkage was found with five different isozyme loci, with theIg-l locus or with C5 serum activity. Also in vivo resistance showed strong linkage with theH-2 complex. In (A x CBA)F₁ x A backcross mice, a weak linkage was found with the coat color locusC. There was a correlation between in vitro killer activity and in vivo resistance in the same backcross mice. In vivo resistance was particularly strong in mice that combined theH-2 ^b -linked resistance factor with a high cytolytic activity in vitro.     

At the edge and on the top: molecular identification and ecology of Daphnia dentifera and D. longispina in high-altitude Asian lakes

The occurrence of members of the highly diverse Daphnia longispina complex in Southern and Central Asian high-mountain lakes has been recognized for more than a century. Until now, however, no molecular data have been available for these populations inhabiting the “Roof of the World.” Here, we present the first identification for D. gr. longispina from that region based on a molecular phylogeny. Our findings show that alpine lakes in the Pamir and Himalaya mountains host populations of widespread species of the complex, for which these are the highest known localities. A spineless morph from the Himalaya region, previously labeled as D. longispina var. aspina, was clustering tightly with D. dentifera, while a population from the Pamir mountain range was grouped with D. longispina. In addition, we analyzed ecological data available for lakes in the Khumbu region (Himalaya) to investigate ecological preferences of non-pigmented D. gr. longispina. The identified factors can at least partly be related to avoidance of high UV conditions by this species. We conclude that the widespread species D. dentifera and D. longispina also colonized the Asian high-mountain lakes, and identify the need for further research to trace the possible effect of rapid environmental changes in this region on the diversity and ecology of high-altitude Daphnia populations.     

Interpretation of the last‐glacial vegetation of eastern‐central Europe using modern analogues from southern Siberia

Aim Interpretation of fossil pollen assemblages may benefit greatly from comparisons with modern palynological and vegetation analogues. To interpret the full‐ and late‐glacial vegetation in eastern‐central Europe we compared fossil pollen assemblages from this region with modern pollen assemblages from various vegetation types in southern Siberia, which presumably include the closest modern analogues of the last‐glacial vegetation of central Europe. Location Czech and Slovak Republics (fossil pollen assemblages); Western Sayan Mountains, southern Siberia (modern pollen assemblages). Methods Eighty‐eight modern pollen spectra were sampled in 14 vegetation types of Siberian forest, tundra and steppe, and compared with the last‐glacial pollen spectra from seven central European localities using principal components analysis. Results Both full‐ and late‐glacial pollen spectra from the valleys of the Western Carpathians (altitudes 350–610 m) are similar to modern pollen spectra from southern Siberian taiga, hemiboreal forest and dwarf‐birch tundra. The full‐glacial and early late‐glacial pollen spectra from lowland river valleys in the Bohemian Massif (altitudes 185–190 m) also indicate the presence of patches of hemiboreal forest or taiga. Other late‐glacial pollen spectra from the Bohemian Massif suggest an open landscape with steppe or tundra or a mosaic of both, possibly with small patches of hemiboreal forest. Main conclusions Our results are consistent with the hypothesis that during the full glacial and late glacial, the mountain valleys of the north‐western Carpathians supported taiga or hemiboreal forest dominated by Larix, Pinus cembra, Pinus sylvestris and Picea, along with some steppic or tundra formations. Forests tended to be increasingly open or patchy towards the west (Moravian lowlands), gradually passing into the generally treeless landscape of Bohemia, with possible woodland patches in locally favourable sites.     

Characteristics of Gloeophyllum trabeum alcohol oxidase, an extracellular source of H2O2 in brown rot decay of wood

A novel alcohol oxidase (AOX) has been purified from mycelial pellets of the wood-degrading basidiomycete Gloeophyllum trabeum and characterized as a homooctameric nonglycosylated protein with native and subunit molecular masses of 628 and 72.4 kDa, containing noncovalently bonded flavin adenine dinucleotide. The isolated AOX cDNA contained an open reading frame of 1,953 bp translating into a polypeptide of 651 amino acids displaying 51 to 53% identity with other published fungal AOX amino acid sequences. The enzyme catalyzed the oxidation of short-chain primary aliphatic alcohols with a preference for methanol (K(m) = 2.3 mM, k(cat) = 15.6 s(-1)). Using polyclonal antibodies and immunofluorescence staining, AOX was localized on liquid culture hyphae and extracellular slime in sections from degraded wood and on cotton fibers. Transmission electron microscopy immunogold labeling localized the enzyme in the hyphal periplasmic space and wall and on extracellular tripartite membranes and slime, while there was no labeling of hyphal peroxisomes. AOX was further shown to be associated with membranous or slime structures secreted by hyphae in wood fiber lumina and within the secondary cell walls of degraded wood fibers. The differences in AOX targeting compared to the known yeast peroxisomal localization were traced to a unique C-terminal sequence of the G. trabeum oxidase, which is apparently responsible for the protein's different translocation. The extracellular distribution and the enzyme's abundance and preference for methanol, potentially available from the demethylation of lignin, all point to a possible role for AOX as a major source of H(2)O(2), a component of Fenton's reagent implicated in the generally accepted mechanisms for brown rot through the production of highly destructive hydroxyl radicals.