First description of the helminth community in the Whiskered Tern Chlidonias hybrida (Lariforma: Sternidae) in France

First description of the helminth community in the Whiskered Tern Chlidonias hybrida (Lariforma: Sternidae) in France.- The degree of knowledge of the helminth community associated with bird members of the Sternidae family is largely limited and totally absent in some bird species such as the Whiskered Tern Chlidonias hybrida. In the present study, the helminth community is described in this species for the first time from dead chicks collected in France (Lake Grand-Lieu). An analysis of the parasite load in relation to chick age and mortality causes was also performed. The helminth community was composed of five families of which Strigeidae were the most frequent (prevalence: 91.7 %) and abundant (mean intensity: 45.6 ± 10.1 parasites per infested chick). This is the first record of Strigeidae in the Whiskered Tern and also of Capillaridae and Plagiorchiidae in Sternidae. Whatever the chick age, the intensity of parasites in chicks dead from accidental causes (6-12 parasites per chick) was lower than that found in birds (mainly in older chicks, i.e. > 10 days old) whose mortality causes stayed unknown (78 ± 30 parasites per chick, and up to 107 parasites in one chick). Based on these results, we suggest that parasitism is a factor that might affect significantly survival of Whiskered Tern chicks

Transcription factories in the context of the nuclear and genome organization

In the eukaryotic nucleus, genes are transcribed in transcription factories. In the present review, we re-evaluate the models of transcription factories in the light of recent and older data. Based on this analysis, we propose that transcription factories result from the aggregation of RNA polymerase II-containing pre-initiation complexes assembled next to each other in the nuclear space. Such an aggregation can be triggered by the phosphorylation of the C-terminal domain of RNA polymerase II molecules and their interaction with various transcription factors. Individual transcription factories would thus incorporate tissue-specific, co-regulated as well as housekeeping genes based only on their initial proximity to each other in the nuclear space. Targeting genes to be transcribed to protein-dense factories that contain all factors necessary for transcription initiation and elongation through chromatin templates clearly favors a more economical utilization and better recycling of the transcription machinery

Cloning and characterization of a novel oocyte-specific gene encoding an F-Box protein in rainbow trout (Oncorhynchus mykiss)

BACKGROUND: Oocyte-specific genes play critical roles in oogenesis, folliculogenesis and early embryonic development. The objectives of this study were to characterize the expression of a novel oocyte-specific gene encoding an F-box protein during ovarian development in rainbow trout, and identify its potential interacting partners in rainbow trout oocytes. METHODS: Through analysis of expressed sequence tags (ESTs) from a rainbow trout oocyte cDNA library, a novel transcript represented by ESTs only from the oocyte library was identified. The complete cDNA sequence for the novel gene (named fbxoo) was obtained by assembling sequences from an EST clone and a 5′RACE product. The expression and localization of fbxoo mRNA and protein in ovaries of different developmental stages were analyzed by quantitative real time PCR, immunoblotting, in situ hybridization and immunohistochemistry. Identification of Fbxoo binding proteins was performed by yeast two-hybrid screening. RESULTS: fbxoo mRNA is specifically expressed in mature oocytes as revealed by tissue distribution analysis. The fbxoo cDNA sequence is 1,996 bp in length containing an open reading frame, which encodes a predicted protein of 514 amino acids. The novel protein sequence does not match any known protein sequences in the NCBI database. However, a search of the Pfam protein database revealed that the protein contains an F-box motif at the N-terminus, indicating that Fbxoo is a new member of the F-box protein family. The expression of fbxoo mRNA and protein is high in ovaries at early pre-vitellogenesis stage, and both fbxoo mRNA and protein are predominantly expressed in early pre-vitellogenic oocytes. Several proteins including tissue inhibitor of metalloproteinase 2 (Timp2) were identified as potential Fbxoo protein binding partners. CONCLUSIONS: Results suggest that the novel oocyte-specific F-box protein may play an important role in early oocyte development by regulating other critical proteins involved in oogenesis in rainbow trout

An Unexpected Case of Heterospecific Altruistic Behaviour in a Non-Breeding Migrant Tern (Charadriformes, Sternidae)

Abstract Observations of birds feeding chicks or fledglings of a different species have already been reported in many publications. However, the benefits of the altruistic behaviour are not easy to understand, as benefits and costs of this behaviour have been poorly identified. In May 2013, in a wetland in Central Italy (Piana Fiorentina, Tuscany), some cases of interspecific feeding of an Eurasian Coot Fulica atra chick by an adult non breeding Whiskered Tern Chlidonias hybrida were witnessed. We suggest that the behaviour of the Tern was triggered by the begging of the chick or by its own hormonal status

Hydropériode des zones humides : un enjeu de gestion clé pour les poissons

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