Vietnamese chickens: a gate towards Asian genetic diversity

BACKGROUND: Chickens represent an important animal genetic resource and the conservation of local breeds is an issue for the preservation of this resource. The genetic diversity of a breed is mainly evaluated through its nuclear diversity. However, nuclear genetic diversity does not provide the same information as mitochondrial genetic diversity. For the species Gallus gallus, at least 8 maternal lineages have been identified. While breeds distributed westward from the Indian subcontinent usually share haplotypes from 1 to 2 haplogroups, Southeast Asian breeds exhibit all the haplogroups. The Vietnamese Ha Giang (HG) chicken has been shown to exhibit a very high nuclear diversity but also important rates of admixture with wild relatives. Its geographical position, within one of the chicken domestication centres ranging from Thailand to the Chinese Yunnan province, increases the probability of observing a very high genetic diversity for maternal lineages, and in a way, improving our understanding of the chicken domestication process. RESULTS: A total of 106 sequences from Vietnamese HG chickens were first compared to the sequences of published Chinese breeds. The 25 haplotypes observed in the Vietnamese HG population belonged to six previously published haplogroups which are: A, B, C, D, F and G. On average, breeds from the Chinese Yunnan province carried haplotypes from 4.3 haplogroups. For the HG population, haplogroup diversity is found at both the province and the village level (0.69).The AMOVA results show that genetic diversity occurred within the breeds rather than between breeds or provinces. Regarding the global structure of the mtDNA diversity per population, a characteristic of the HG population was the occurrence of similar pattern distribution as compared to G. gallus spadiceus. However, there was no geographical evidence of gene flow between wild and domestic populations as observed when microsatellites were used. CONCLUSIONS: In contrast to other chicken populations, the HG chicken population showed very high genetic diversity at both the nuclear and mitochondrial levels. Due to its past and recent history, this population accumulates a specific and rich gene pool highlighting its interest and the need for conservation

Monalysin, a Novel ß-Pore-Forming Toxin from the Drosophila Pathogen Pseudomonas entomophila, Contributes to Host Intestinal Damage and Lethality

Pseudomonas entomophila is an entomopathogenic bacterium that infects and kills Drosophila. P. entomophila pathogenicity is linked to its ability to cause irreversible damages to the Drosophila gut, preventing epithelium renewal and repair. Here we report the identification of a novel pore-forming toxin (PFT), Monalysin, which contributes to the virulence of P. entomophila against Drosophila. Our data show that Monalysin requires N-terminal cleavage to become fully active, forms oligomers in vitro, and induces pore-formation in artificial lipid membranes. The prediction of the secondary structure of the membrane-spanning domain indicates that Monalysin is a PFT of the ß-type. The expression of Monalysin is regulated by both the GacS/GacA two-component system and the Pvf regulator, two signaling systems that control P. entomophila pathogenicity. In addition, AprA, a metallo-protease secreted by P. entomophila, can induce the rapid cleavage of pro-Monalysin into its active form. Reduced cell death is observed upon infection with a mutant deficient in Monalysin production showing that Monalysin plays a role in P. entomophila ability to induce intestinal cell damages, which is consistent with its activity as a PFT. Our study together with the well-established action of Bacillus thuringiensis Cry toxins suggests that production of PFTs is a common strategy of entomopathogens to disrupt insect gut homeostasis

Redução da estigmatização e da discriminação das pessoas idosas com transtornos mentais: uma declaração técnica de consenso

This technical consensus statement is jointly produced by the Old Age Psychiatry section of the World Psychiatric Association and the World Health Organization, with the collaboration of several NGOs and the participation of experts from different regions. It is intended to be a tool for (i) promoting debate at all levels on the stigmatization of older people with mental disorders; (ii) outlining the nature, causes and consequences of this stigmatization; and (iii) promoting and suggesting policies, programs and actions to combat this stigmatization.A Organização Mundial da Saúde (OMS) e a Seção de Psiquiatria da Pessoa Idosa da Associação Mundial de Psiquiatria (AMP), em colaboração com um grupo interdisciplinar de representantes das principais associações internacionais e organizações não-governamentais implicadas na saúde mental das pessoas idosas, publicaram três declarações técnicas de consenso sobre a psiquiatria da pessoa idosa (1), a organização dos cuidados em psiquiatria da pessoa idosa (2) e o ensino da psiquiatria da pessoa idosa (3). O Dia Mundial da Saúde 2001, cujo tema foi "Não à exclusão, sim aos cuidados", deu origem a uma nova reunião de consenso sobre o tema da estigmatização e discriminação das pessoas idosas com transtornos mentais. Essa nova reunião foi realizada em Lausanne nos dias 8 e 9 de outubro de 2001 e produziu uma declaração técnica de consenso. O texto inicial foi publicado pela OMS e AMP em inglês. Este artigo apresenta a versão em português desse documento

Frequency fluctuations in silicon nanoresonators

Frequency stability is key to performance of nanoresonators. This stability is thought to reach a limit with the resonator's ability to resolve thermally-induced vibrations. Although measurements and predictions of resonator stability usually disregard fluctuations in the mechanical frequency response, these fluctuations have recently attracted considerable theoretical interest. However, their existence is very difficult to demonstrate experimentally. Here, through a literature review, we show that all studies of frequency stability report values several orders of magnitude larger than the limit imposed by thermomechanical noise. We studied a monocrystalline silicon nanoresonator at room temperature, and found a similar discrepancy. We propose a new method to show this was due to the presence of frequency fluctuations, of unexpected level. The fluctuations were not due to the instrumentation system, or to any other of the known sources investigated. These results challenge our current understanding of frequency fluctuations and call for a change in practices

An ephemeral Frenkel pair in iridium

After neutron activation, iridium samples have been kept at low temperature (22 K). The electrical resistivity decreases or increases with time according to whether the activation was moderate or high. A coherent interpretation is given implying the recoil-induced creation of a Frenkel pair during activation and its subsequent annihilation, with a probability ≃ 0.8, due to a second subthreshold recoil.Après activation sous flux de neutrons, de l'iridium est maintenu à basse température (22 K). La résistivité électrique décroît ou croit au cours du temps suivant que l'activation a été faible ou forte. Une interprétation cohérente est donnée qui implique la création, par recul radioactif, d'une paire de Frenkel durant l'activation, et son annihilation ultérieure (avec une probabilité égale à ≃ 0,8) par un second recul sous seuil