Wolbachia-Mediated Male Killing Is Associated with Defective Chromatin Remodeling

Male killing, induced by different bacterial taxa of maternally inherited microorganisms, resulting in highly distorted female-biased sex-ratios, is a common phenomenon among arthropods. Some strains of the endosymbiont bacteria Wolbachia have been shown to induce this phenotype in particular insect hosts. High altitude populations of Drosophila bifasciata infected with Wolbachia show selective male killing during embryonic development. However, since this was first reported, circa 60 years ago, the interaction between Wolbachia and its host has remained unclear. Herein we show that D. bifasciata male embryos display defective chromatin remodeling, improper chromatid segregation and chromosome bridging, as well as abnormal mitotic spindles and gradual loss of their centrosomes. These defects occur at different times in the early development of male embryos leading to death during early nuclear division cycles or large defective areas of the cellular blastoderm, culminating in abnormal embryos that die before eclosion. We propose that Wolbachia affects the development of male embryos by specifically targeting male chromatin remodeling and thus disturbing mitotic spindle assembly and chromosome behavior. These are the first observations that demonstrate fundamental aspects of the cytological mechanism of male killing and represent a solid base for further molecular studies of this phenomenon

The PLATO 2.0 mission

PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4-16 mag). It focusses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4-10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA's Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science

Modelos explicativos e de intervenção na promoção da saúde do trabalhador Modelos explicativos de intervención en la promoción de la salud del trabajador Explanative and intervention models in workers' health promotion

OBJETIVO: Buscar evidências científicas, na literatura, de modelos explicativos e de intervenção para promoção da saúde do trabalhador e prevenção de acidentes de trabalho com material biológico. MÉTODOS: Revisão integrativa da literatura. RESULTADOS: Onze artigos atenderam aos critérios estabelecidos, 36,4% usaram modelos explicativos centrados no comportamento individual ou possibilitaram a interação entre os indivíduos e prestadores de serviço, 63,6% usaram modelos de intervenção para a promoção da saúde de trabalhadores expostos a riscos biológicos. CONCLUSÃO: Os modelos de intervenção são os mais relevantes na área de saúde do trabalhador, pois direcionam para um modo de dispor os meios técnicos e científicos para intervir sobre riscos e danos à saúde, incorporando uma lógica que orienta as intervenções técnicas sobre os problemas e necessidades dos trabalhadores.<br>OBJETIVO: Buscar evidencias científicas, en la literatura, de modelos explicativos y de intervención para la promoción de la salud del trabajador y prevención de accidentes de trabajo con material biológico. MÉTODOS: Revisión integrada de la literatura. RESULTADOS: Once artículos atendieron a los criterios establecidos, 36,4% usaron modelos explicativos centrados en el comportamiento individual o posibilitaron la interacción entre los individuos y prestadores de servicio, 63,6% usaron modelos de intervención para la promoción de la salud de trabajadores expuestos a riesgos biológicos. CONCLUSIÓN: Los modelos de intervención son los más relevantes en el área de salud del trabajador, pues orientan hacia un modo de disponer los medios técnicos y científicos para intervenir sobre los riesgos y daños a la salud, incorporando una lógica que orienta las intervenciones técnicas sobre los problemas y necesidades de los trabajadores.<br>OBJECTIVE: To search for scientific evidence in literature of explanative and intervention models to promote workers' health and prevent occupational accidents with biological material. METHODS: Integrative literature review. RESULTS: Eleven articles met the inclusion criteria, with 36.4% of them using explanative models centered on the individual behavior or enabling the interaction between individuals and service providers; 63.6% used intervention models to promote the health of workers exposed to biological risks. CONCLUSION: Intervention models are more relevant in the worker health area, since they organize the technical and scientific means to intervene in risks and damage to health, incorporating a logic that guides the technical interventions for the problems and necessities of the workers

Yield and carcass composition of broilers fed with diets based on the concept of crude protein or ideal protein

Two experiments were conducted to evaluate the effect of diets formulated using the criteria of crude protein (CP) and ideal protein (IP) on the yield and carcass composition of male and female broilers. Birds of two broilers strains (Hybro G and Hybro PG) were reared from 1 to 42 days of age during the summer, with average temperatures of 26&deg;C. A completely randomized experimental design was used in a 2 x 2 factorial arrangement, with 6 replicates and 20 birds per pen. On day 42, four birds from each experimental unit were killed and carcass yield and composition were determined. Breast yield was higher in males and females fed the IP-based diet than in birds fed the CP-based diet. Abdominal fat pad and carcass crude protein were statistically similar between the two protein criteria and between strains. Carcass amino acid levels evidenced higher levels of Met, Lys, Met+Cys and Thr in the males fed IP-based diets. No differences were seen between the two criteria for the females. Diets formulated according to IP resulted in better carcass and breast yield, both for males and females