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771.
Hofit Kol-Maimon Zvi Mendel José Carlos Franco Murad Ghanim 《Die Naturwissenschaften》2014,101(10):791-802
Mealybugs have a haplodiploid reproduction system, with paternal genome elimination (PGE); the males are diploid soon after fertilization, but during embryogenesis, the male paternal set of chromosomes becomes heterochromatic (HC) and therefore inactive. Previous studies have suggested that paternal genes can be passed on from mealybug males to their sons, but not necessarily by any son, to the next generation. We employed crosses between two mealybug species—Planococcus ficus (Signoret) and Planococcus citri (Risso)—and between two populations of P. ficus, which differ in their mode of pheromone attraction, in order to demonstrate paternal inheritance from males to F2 through F1 male hybrids. Two traits were monitored through three generations: mode of male pheromone attraction (pherotype) and sequences of the internal transcribed spacer 2 (ITS2) gene segment (genotype). Our results demonstrate that paternal inheritance in mealybugs can occur from males to their F2 offspring, through F1 males (paternal line). F2 backcrossed hybrid males expressed paternal pherotypes and ITS2 genotypes although their mother originated through a maternal population. Further results revealed other, hitherto unknown, aspects of inheritance in mealybugs, such as that hybridization between the two species caused absence of paternal traits in F2 hybrid females produced by F1 hybrid females. Furthermore, hybridization between the two species raised the question of whether unattracted males have any role in the interactions between P. ficus and P. citri. 相似文献
772.
Carlos David Silv Lizeth Beristain-Montiel Flor de Maria Cuervo-Lpez Anne-Claire Texier 《环境科学学报(英文版)》2014,26(9):1885-1893
The ability of a nitrifying sludge to oxidize p-cresol was evaluated in a sequential batch reactor (SBR). p-Cresol was first transformed to p-hydroxybenzaldehyde and p-hydroxybenzoate, which were later mineralized. The specific rates of p-cresol consumption increased throughout the cycles. The bacterial population dynamics were monitored by using denaturing gradient gel electrophoresis 0DGGE) and sequencing of DGGE fragments. The ability of the sludge to consume p-cresol and intermediates might be related to the presence of species such as Variouorax paradoxus and Thauera mechernichensis, p-Cresol (25 to 200 mg C/L) did not affect the nitrifying SBR performance (ammonium consumption efficiency and nitrate production yield were close to 100% and 1, respectively). This may be related to the high stability observed in the nitrifying communities. It was shown that a nitrifying SBR may be a good alternative to eliminate simultaneously ammonium and p-cresol, maintaining stable the respiratory process as the bacterial community. 相似文献
773.
Jesus Rodriguez-Manzano Ayalkibet Hundesa Byron Calgua Anna Carratala Carlos Maluquer de Motes Marta Rusiñol Vanessa Moresco Ana Paula Ramos Fernando Martínez-Marca Miquel Calvo Celia Regina Monte Barardi Rosina Girones Sílvia Bofill-Mas 《Food and environmental virology》2014,6(1):31-41
Shellfish complying with European Regulations based on quantification of fecal bacterial indicators (FIB) are introduced into markets; however, information on viruses, more stable than FIB, is not available in the literature. To assess the presence of noroviruses (NoVs) GI and GII and human adenoviruses (HAdV) in domestic and imported mussels and clams (n = 151) their presence was analyzed during winter seasons (2004–2008) in north-west Spanish markets through a routine surveillance system. All samples tested negative for NoV GI and 13 % were positive for NoV GII. The role of HAdV as viral indicator was evaluated in 20 negative and 10 positive NoV GII samples showing an estimated sensitivity and specificity of HAdV to predict the presence of NoV GII of 100 and 74 % (cut-off 0.5). The levels of HAdV and NoVs and the efficiency of decontamination in shellfish depuration plants (SDP) were evaluated analyzing pre- and post-depurated mussels collected in May–June 2010 from three different SDP. There were no statistically significant differences in the prevalence and quantification of HAdV between pre- and post-depurated shellfish and between seawater entering and leaving the depuration systems. Moreover, infectious HAdV were detected in depurated mussels. These results confirm previous studies showing that current controls and depuration treatments limiting the number of FIB do not guarantee the absence of viruses in shellfish. 相似文献
774.
Leonardo A. Venerus Javier E. Ciancio Carla Riva-Rossi Elizabeth A. Gilbert-Horvath Atila E. Gosztonyi John Carlos Garza 《Die Naturwissenschaften》2013,100(7):645-658
Rockfishes of the genus Sebastes are extensively distributed in the Pacific and Atlantic oceans. Although the occurrence of two morphologically similar species in the Southern Hemisphere, Sebastes oculatus and Sebastes capensis, is now clearly established, the taxonomic status and phylogeographic patterns for the genus in the region have not yet been completely resolved. In this study, we provide new insights into the taxonomy and evolutionary relationships of rockfishes inhabiting the Southwestern Atlantic Ocean, off the coast of mainland Argentina, by combining mitochondrial DNA (mtDNA) control region sequences, microsatellite data, and color pattern analyses. Differences in coloration (“dark” and “light” fish) together with bathymetric segregation between color morphotypes were evident from fish collection and literature review. In addition, the mtDNA phylogenetic analysis and Bayesian clustering analysis using microsatellite data separated the fish into two distinct groups (F ST?=?0.041), most likely representing incipient species. Our results suggest that speciation-by-depth in the absence of physical barriers could be a widespread mechanism of speciation in Sebastes from both the Northern and Southern Hemispheres. Nevertheless, the degree of genetic differentiation found, added to the large number of individuals displaying high levels of admixture, points to the occurrence of incomplete reproductive barriers between color morphotypes. Beyond the taxonomic and phylogeographic implications of our findings, the occurrence of distinct groups of Sebastes off the coast of Argentina being targeted by different fisheries (angling and trawling) has consequences for the design and implementation of appropriate fishery regulations to avoid overharvest of either group. 相似文献
775.
Carlos Cerdan Cristina Gazulla Marco Raugei Eva Martinez Pere Fullana-i-Palmer 《Journal of Cleaner Production》2009,17(18):1638-1643
Eco-design is a valuable approach in order to reduce the environmental impact associated with a product system, by introducing environmental considerations early on in its design. Different strategies are possible for the implementation of eco-design, depending on the intended goals as well as the characteristics of the products. The present work proposes a series of eco-design indicators and tests to what extent the application of these simple indicators provides a reliable indication of the reduction of environmental impact, as measured by commonly employed Life Cycle Impact Assessment (LCIA) indicators. The product chosen for the case study was a water source heat pump. Two of the newly-developed indicators were applied and compared to LCIA indicators, focussing on design for disassembly and for recycling. A good and robust correlation was found, providing support to the thesis that these simple eco-design indicators can be used as a proxy to quickly and effectively gauge the environmental improvements introduced in a product system at the design stage. 相似文献
776.
Pollination is an ecological process that provides important services to humans. Pollination service in agroecosystems depends on several factors, including the land management systems used by farmers. Here we focused on the effects of insect pollinator diversity on coffee fruit production along a gradient of management systems in central Veracruz, Mexico. The gradient ranged from low environmental impact management systems (the native forest is not completely removed) to high environmental impact management systems (the native forest is completely removed). We hypothesized that pollinator diversity should be higher in low-impact systems. Then, if fruit production is positively related to pollinator diversity, plantations with low-impact management systems should display higher fruit production than plantations with high-impact management systems. We used observational and experimental data to test this hypothesis. Our results indicated that low-impact management systems have higher species richness and relative diversity (measured with the Shannon-Wiener diversity index) of pollinators than high-impact management systems. In all cases, fruit production was positively related with species richness and diversity of pollinators. Moreover, fruit production was higher in low-impact than in high-impact management systems. These results suggest that the diversity of insect pollinators can be influenced by the management system applied by farmers, and that such effects may have strong consequences on coffee fruit production. 相似文献
777.
778.
Juan I. Canale Carlos A. Scanferla Federico L. Agnolin Fernando E. Novas 《Die Naturwissenschaften》2009,96(3):409-414
A nearly complete skeleton of the new abelisaurid Skorpiovenator bustingorryi is reported here. The holotype was found in Late Cenomanian–Early Turonian outcrops of NW Patagonia, Argentina. This new
taxon is deeply nested within a new clade of South American abelisaurids, named Brachyrostra. Within brachyrostrans, the skull
shortening and hyperossification of the skull roof appear to be correlated with a progressive enclosure of the orbit, a set
of features possibly related to shock-absorbing capabilities. Moreover, the development of horn-like structures and differential
cranial thickening appear to be convergently acquired within Abelisauridae. Based on the similarities between Skorpiovenator and carcharodontosaurid tooth morphology, we suggest that isolated teeth originally referred as post-Cenomanian Carcharodontosauridae
most probably belong to abelisaurids.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
779.
The Prestige oil spill in November 2002 is considered the biggest large-scale catastrophe of its type in Europe, thousands of seabirds dying in the subsequent months. Here, the total concentration of 16 polycyclic aromatic hydrocarbons (TPAH) was measured in the blood cell fraction of adult and chick yellow-legged gulls (Larus michahellis) from unoiled and oiled coastal areas in North Western Spain. In addition, hematocrit, plasma metabolites, electrolytes and enzymes, as well as body mass were determined in the same individuals. Our results strongly suggest the presence of health damages of sublethal nature in adult gulls breeding in oiled colonies 17 months after the Prestige oil spill. This is supported by the following evidences: (1) gulls sampled in unoiled and oiled colonies differed in blood TPAH levels, (2) gulls sampled in unoiled and oiled colonies differed in several blood parameters indicative of physiological disorders, and (3) TPAH in blood was significantly related to several of these parameters. Differences in the level of asparatate aminotransferase (AST), gamma-glutamyl transferase (GGT), total protein, glucose and inorganic phosphorus suggest damages on some vital organs (i.e. liver and kidney) in adult birds from oiled areas. Meanwhile, chicks presented weaker effects than adults, showing only between-area differences in hematocrit. Since TPAH levels in blood did not differ between both age-groups, the stronger effects on adults should be due to their longer exposure to these pollutants and/or to severe exposure in the months following the spill. The presence of PAHs in chicks indicates that these pollutants were incorporated into the food chain because nestlings would have been only exposed to contaminated organisms in the diet (e.g. fishes and crustaceans). Our findings support the view that PAHs may deeply alter the physiology of seabirds, and emphasize the necessity of quantifying the circulating levels of these compounds in order to evaluate the sublethal effects associated to large oil spills. 相似文献
780.
Firmat C Gomes Rodrigues H Hutterer R Rando JC Alcover JA Michaux J 《Die Naturwissenschaften》2011,98(1):33-37
Malpaisomys insularis is a mouse-like rodent endemic to the eastern Canary Islands. It became extinct during the fourteenth century. It was a remarkable
species living under hyperarid conditions. A dental microwear analysis was performed in order to determine its former diet.
The elevated number of fine scratches found in Malpaisomys molars suggests that it consumed a significant part of Poaceae, grass consumption leaving the most distinctive features on
dental wear facets. A graminivorous diet with a high amount of abrasive items is in agreement with the broad teeth of Malpaisomys, considered as adapted to grass consumption. However, in the absence of potential competitors over its native range, it is
likely that Malpaisomys also foraged on dicots to meet higher nutrient and energetic requirements. The ecology of Malpaisomys is discussed from these results in the context of the desertic climatic conditions of the eastern Canary Islands and with
a special concern on its small body size in contrast to other large-sized island murine species such as the giant rats of
the central Canary Islands. 相似文献