Environmental conditions at arrival to the wintering grounds and during spring migration affect population dynamics of barn swallows Hirundo rustica breeding in Northern Italy

Several populations of long-distance migratory birds are currently suffering steep demographic declines. The identification of the causes of such declines is difficult because population changes may be driven by events occurring in distant geographical areas during different phases of the annual life-cycle of migrants. Furthermore, wintering areas and migration routes of populations of small-sized species are still largely unknown, with few exceptions. In this paper we identified the critical phases of the annual life-cycle that most influence the population dynamics of a small passerine, the Barn Swallow Hirundo rustica. We used information on temporal dynamics of a population breeding in Northern Italy, whose wintering range and timing of migration have been recently described by miniaturised tracking dataloggers. Our results indicated that primary productivity in the wintering grounds in the month when most individuals arrive from autumn migration and primary productivity in an area that is probably a stopover site during spring migration, influenced population dynamics more than habitat conditions at the breeding grounds. By using annual variation in primary productivity at the wintering grounds and stopover sites as predictors, we replicated the observed interannual population changes with great accuracy. However, the steep decline recently suffered by the population could be replicated only by including a constant annual decline in the model, suggesting that changes in primary productivity only predicted the interannual variation around the long-term trend. Our study therefore suggests the existence of critical periods during wintering and migration that may have large impact on population fluctuations of migrant birds.     

Intraspecific Variation in Mitogenomes of Five <Emphasis Type="Italic">Crassostrea</Emphasis> Species Provides Insight into Oyster Diversification and Speciation

A large number of Crassostrea oysters are found in Asia-Pacific. While analyses of interspecific variation have helped to establish historical relationships among these species, studies on intraspecific variation are necessary to understand their recent evolutionary history and current forces driving population biology. We resequenced 18 and analyzed 31 mitogenomes of five Crassostrea species from China: Crassostrea gigas, Crassostrea angulata, Crassostrea sikamea, Crassostrea ariakensis, and Crassostrea hongkongensis. Our analysis finds abundant insertions, deletions, and single-nucleotide polymorphisms in all species. Intraspecific variation varies greatly among species with polymorphic sites ranging from 54 to 293 and nucleotide diversity ranging from 0.00106 to 0.00683. In all measurements, C. hongkongensis that has the narrowest geographic distribution exhibits the least sequence diversity; C. ariakensis that has the widest distribution shows the highest diversity, and species with intermediate distribution show intermediate levels of diversity. Low sequence diversity in C. hongkongensis may reflect recent bottlenecks that are probably exacerbated by human transplantation. High diversity in C. ariakensis is likely due to divergence of northern and southern China populations that have been separated without gene flow. The significant differences in mitogenome diversity suggest that the five sister species of Crassostrea have experienced different evolutionary forces since their divergence. The recent divergence of two C. ariakensis populations and the C. gigas/angulata species complex provides evidence for continued diversification and speciation of Crassostrea species along China’s coast, which are shaped by unknown mechanisms in a north–south divide.     

Purification,Chemical Characterization,and Bioactivity of an Extracellular Polysaccharide Produced by the Marine Sponge Endogenous Fungus <Emphasis Type="Italic">Alternaria</Emphasis> sp. SP-32

Marine sponges are ancient and simple multicellular filter-feeding invertebrates attached to solid substrates in benthic habitats and host a variety of fungi both inside and on their surface because of its unique ingestion and digest system. Investigation on marine sponge-associated fungi mainly focused on the small molecular metabolites, yet little attention had been paid to the extracellular polysaccharides. In this study, a homogeneous extracellular polysaccharide AS2-1 was obtained from the fermented broth of the marine sponge endogenous fungus Alternaria sp. SP-32 using ethanol precipitation, anion-exchange, and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that AS2-1 was composed of mannose, glucose, and galactose with a molar ratio of 1.00:0.67:0.35, and its molecular weight was 27.4 kDa. AS2-1 consists of a mannan core and a galactoglucan chain. The mannan core is composed of (1→6)-α-Manp substituted at C-2 by (1→2)-α-Manp with different degrees of polymerization. The galactoglucan chain consists of (1→6)-α-Glcp residues with (1→6)-β-Galf residues attached to the last glucopyranose residue at C-6. (1→6)-β-Galf residues have additional branches at C-2 consisting of disaccharide units of (1→2)-β-Galf and (1→2)-α-Glcp residues. The glucopyranose residue of the galactoglucan chain is linked to the mannan core. AS2-1 possessed a high antioxidant activity as evaluated by scavenging of 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals in vitro. AS2-1 was also evaluated for cytotoxic activity on Hela, HL-60, and K562 cell lines by the MTT and SRB methods. The investigation demonstrated that AS2-1 was a novel extracellular polysaccharide with different characterization from extracellular polysaccharides produced by other marine microorganisms.     

cDNA Microarray Analysis Revealing Candidate Biomineralization Genes of the Pearl Oyster, <Emphasis Type="Italic">Pinctada fucata martensii</Emphasis>

Biomineralization is a common biological phenomenon resulting in strong tissue, such as bone, tooth, and shell. Pinctada fucata martensii is an ideal animal for the study of biomineralization. Here, microarray technique was used to identify biomineralization gene in mantle edge (ME), mantle center (MC), and both ME and MC (ME-MC) for this pearl oyster. Results revealed that 804, 306, and 1127 contigs expressed at least three times higher in ME, MC, and ME-MC as those in other tissues. Blast against non-redundant database showed that 130 contigs (16.17 %), 53 contigs (17.32 %), and 248 contigs (22.01 %) hit reference genes (E?≤??10), among which 91 contigs, 48 contigs, and 168 contigs could be assigned to 32, 26, and 63 biomineralization genes in tissue of ME, MC, and ME-MC at a threshold of 3 times upregulated expression level. The ratios of biomineralization contigs to homologous contigs were similar at 3 times, 10 times, and 100 times of upregulated expression level in either ME, MC, or ME-MC. Moreover, the ratio of biomineralization contigs was highest in MC. Although mRNA distribution characters were similar to those in other studies for eight biomineralization genes of PFMG3, Pif, nacrein, MSI7, mantle gene 6, Pfty1, prismin, and the shematrin, most biomineralization genes presented different expression profiles from existing reports. These results provided massive fundamental information for further study of biomineralization gene function, and it may be helpful for revealing gene nets of biomineralization and the molecular mechanisms underlining formation of shell and pearl for the oyster.     

Species radiation in the Alps: multiple range shifts caused diversification in Ringlet butterflies in the European high mountains

The distributions of European high mountain species are often characterised by small and geographically isolated populations and, in many cases, have highly complex biogeographic histories. The butterfly genus Erebia represents one of the best examples for small-scale diversification in the European high mountain systems and therefore to understand speciation processes and associated range dynamics of high mountain species. In this study, we analysed 17 polymorphic allozyme loci of 1731 individuals from 49 populations representing four species, one of which has three subspecies: Erebia nivalis; Erebia tyndarus; Erebia ottomana; and Erebia cassioides cassioides, Erebia cassioides arvernensis, and Erebia cassioides neleus. Samples were collected in the high mountain systems of Europe (i.e. Pyrenees, Massif Central, Alps, Apennines, Carpathians, Balkan high mountains). Genetic analyses supported all previously accepted species. However, the genetic differentiation within E. cassioides sensu lato into three geographically delimited groups is justifying species rank: E. arvernensis distributed in the Pyrenees, Massif Central and western Alps; E. cassioides sensu stricto in the eastern Alps and Apennines; and E. neleus in the Balkan mountains and the south-western Carpathians. While the differentiation between western Alps and Massif Central as well as eastern Alps and Apennines was low, the Pyrenees as well as the south-western Carpathians were significantly differentiated from the other regions within the respective taxon. In general, the differentiation among the populations of E. neleus was stronger than between populations of the other taxa. Within E. cassioides, we found a west-east gradient of genetic similarity over the eastern Alps. Based on the obtained genetic structures, we are able to delineate glacial refugia and interglacial range modifications. Based on the genetic structures and genetic diversity patterns, we conclude that, triggered by the glacial-interglacial cycles, repeated range modifications have taken place with subsequent differentiation and speciation in the region of the Alps and Balkans. Colonisations to Pyrenees (E. arvernensis pseudomurina, E. arvernensis pseudocarmenta), Massif Central (E. ottomana tardenota, E. a. arvernensis) and Apennines (E. cassioides majellana) appear to be recent and most probably not older than the last interglacial period.     

Taxonomics—next-generation taxonomists

“Taxonomics” is proposed as a short name for the discipline of discovering, recognising, describing and classifying biological entities.     

The influence of adiponectin on the transcriptomic profile of porcine luteal cells

Reproductive functions are closely related to nutritional status. Recent studies suggest that adiponectin may be a hormonal link between them. Adiponectin is an adipocytokine, abundantly expressed in adipose tissues. It plays a dominant role in lipid and carbohydrate metabolism by stimulating fatty acid oxidation, decreasing plasma triglycerides, and increasing cells’ sensitivity to insulin and has direct antiatherosclerotic effects. The hormone is also postulated to play a modulatory role in the regulation of the reproductive system. The aim of this study was to identify differentially expressed genes (DE-genes) in response to adiponectin treatment of porcine luteal ovarian cells. The global expression of genes in the porcine ovary was investigated using the Porcine (V2) Two-color gene expression microarray, 4?×?44 (Agilent, USA). Analysis of the microarray data showed that 701 genes were differentially expressed and 389 genes showed a fold change greater than 1.2 (p?<?0.05). Among this number, 186 genes were up-regulated and 203 were down-regulated. The list of DE-genes was used for gene ontology analyses. The biological process list was generated from up-regulated and down-regulated DE-genes. We found that up-regulated products of DE-genes take part in 30 biological processes and down-regulated products in 9. Analysis of the interaction network among DE-genes showed that adiponectin interacts with genes involved in important processes in luteal cells. These results provide a basis for future work describing the detailed interactions and relationships explaining local regulation of adiponectin actions in the ovary of pigs.