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951.
Frédéric Simard Diego Ayala Guy Colince Kamdem Marco Pombi Joachim Etouna Kenji Ose Jean-Marie Fotsing Didier Fontenille Nora J Besansky Carlo Costantini 《BMC ecology》2009,9(1):17-24
Background
Speciation among members of the Anopheles gambiae complex is thought to be promoted by disruptive selection and ecological divergence acting on sets of adaptation genes protected from recombination by polymorphic paracentric chromosomal inversions. However, shared chromosomal polymorphisms between the M and S molecular forms of An. gambiae and insufficient information about their relationship with ecological divergence challenge this view. We used Geographic Information Systems, Ecological Niche Factor Analysis, and Bayesian multilocus genetic clustering to explore the nature and extent of ecological and chromosomal differentiation of M and S across all the biogeographic domains of Cameroon in Central Africa, in order to understand the role of chromosomal arrangements in ecological specialisation within and among molecular forms. 相似文献952.
Carlo Costantini Diego Ayala Wamdaogo M Guelbeogo Marco Pombi Corentin Y Some Imael HN Bassole Kenji Ose Jean-Marie Fotsing N'Falé Sagnon Didier Fontenille Nora J Besansky Frédéric Simard 《BMC ecology》2009,9(1):1-27
Background
Ongoing lineage splitting within the African malaria mosquito Anopheles gambiae is compatible with ecological speciation, the evolution of reproductive isolation by divergent natural selection acting on two populations exploiting alternative resources. Divergence between two molecular forms (M and S) identified by fixed differences in rDNA, and characterized by marked, although incomplete, reproductive isolation is occurring in West and Central Africa. To elucidate the role that ecology and geography play in speciation, we carried out a countrywide analysis of An. gambiae M and S habitat requirements, and that of their chromosomal variants, across Burkina Faso.Results
Maps of relative abundance by geostatistical interpolators produced a distinct pattern of distribution: the M-form dominated in the northernmost arid zones, the S-form in the more humid southern regions. Maps of habitat suitability, quantified by Ecological Niche Factor Analysis based on 15 eco-geographical variables revealed less contrast among forms. M was peculiar as it occurred proportionally more in habitat of marginal quality. Measures of ecological niche breadth and overlap confirmed the mismatch between the fundamental and realized patterns of habitat occupation: forms segregated more than expected from the extent of divergence of their environmental envelope – a signature of niche expansion. Classification of chromosomal arm 2R karyotypes by multilocus genetic clustering identified two clusters loosely corresponding to molecular forms, with 'mismatches' representing admixed individuals due to shared ancestral polymorphism and/or residual hybridization. In multivariate ordination space, these karyotypes plotted in habitat of more marginal quality compared to non-admixed, 'typical', karyotypes. The distribution of 'typical' karyotypes along the main eco-climatic gradient followed a consistent pattern within and between forms, indicating an adaptive role of inversions at this geographical scale.Conclusion
Ecological segregation between M and S is consistent with niche expansion into marginal habitats by chromosomal inversion variants during early lineage divergence; presumably, this process is promoted by inter-karyotype competition in the higher-quality core habitat. We propose that the appearance of favourable allelic combinations in other regions of suppressed recombination (e.g. pericentromeric portions defining speciation islands in An. gambiae) fosters development of reproductive isolation to protect linkage between separate chromosomal regions. 相似文献953.
Roberta Esposito Serena Federico Marco Bertolino Valerio Zupo Maria Costantini 《Marine drugs》2022,20(4)
In the last decades, it has been demonstrated that marine organisms are a substantial source of bioactive compounds with possible biotechnological applications. Marine sponges, in particular those belonging to the class of Demospongiae, have been considered among the most interesting invertebrates for their biotechnological potential. In this review, particular attention is devoted to natural compounds/extracts isolated from Demospongiae and their associated microorganisms with important biological activities for pharmacological applications such as antiviral, anticancer, antifouling, antimicrobial, antiplasmodial, antifungal and antioxidant. The data here presented show that this class of sponges is an exciting source of compounds, which are worth developing into new drugs, such as avarol, a hydroquinone isolated from the marine sponge Disidea avara, which is used as an antitumor, antimicrobial and antiviral drug. 相似文献
954.
Maria Filipa Castanheira Sonia Martínez Páramo F. Figueiredo Marco Cerqueira Sandie Millot Catarina C. V. Oliveira Catarina I. M. Martins Luís E. C. Conceição 《Fish physiology and biochemistry》2016,42(5):1441-1452
Individual differences in behaviour and physiological responses to stress are associated with evolutionary adaptive variation and thus raw material for evolution. In farmed animals, the interest in consistent trait associations, i.e. coping styles, has increased dramatically over the last years. However, one of limitations of the available knowledge, regarding the temporal consistency, is that it refers always to short-term consistency (usually few weeks). The present study used an escape response during a net restraining test, previously shown to be an indicative of coping styles in seabream, to investigate long-term consistency of coping styles both over time and during different life history stages. Results showed both short-term (14 days) consistency and long-term (8 months) consistency of escape response. However, we did not found consistency in the same behaviour after sexual maturation when the restraining test was repeated 16, 22 and 23 months after the first test was performed. In conclusion, this study showed consistent behaviour traits in seabream when juveniles, and a loss of this behavioural traits when adults. Therefore, these results underline that adding a life story approach to data interpretation as an essential step forward towards coping styles foreground. Furthermore, a fine-tuning of aquaculture rearing strategies to adapt to different coping strategies may need to be adjusted differently at early stages of development and adults to improve the welfare of farmed fish. 相似文献
955.
956.
Johannes Jansen Martin P. Boer Marco C. A. M. Bink W. Eric van de Weg 《Euphytica》2009,166(1):131-144
Many important crop species are outbreeding. In outbreeding species the search for genes affecting traits is complicated by
the fact that in a single cross up to four alleles may be present at each locus. This paper is concerned with the search for
interacting quantitative trait loci (QTL) in populations which have been obtained by crossing a number of parents. It will
be assumed that the parents are unrelated, but the methods can be extended easily to allow a pedigree structure. The approach
has two goals: (1) finding QTL that are interacting with other loci and also loci which behave additively; (2) finding parents
which segregate at two or more interacting QTL. Large populations obtained by crossing these parents can be used to study
interactions in detail. QTL analysis is carried out by means of regression on predictions of QTL genotypes. 相似文献
957.
Marco Erni Pay Drechsel Hans-Peter Bader Ruth Scheidegger Christian Zurbruegg Rolf Kipfer 《Irrigation and Drainage Systems》2010,24(1-2):113-125
Due to poor urban sanitation farmers in and around most cities in developing countries face highly polluted surface water. While the sanitation challenge has obvious implications for environmental pollution and food safety it can also provide ‘free’ nutrients for irrigating farmers. To understand the related dimensions, a box-flow model was used to identify the most important water and nutrient flows for the Ghanaian city of Kumasi, a rapidly growing African city with significant irrigation in its direct vicinity. The analysis focused on nitrogen and phosphorus and was supplemented by a farm based nutrient balance assessment. Results show that the city constitutes a vast nutrient sink that releases considerable nutrients loads in its passing streams, contributing to the eutrophication of downstream waters. However, farmers have for various practical reasons little means and motivation in using this resource of nutrients. This might change under increasing fertilizer prices as the nutrient load will continue to increase by 40% till 2015 assuming a widening gap between population growth and investments in water supply on one side and investments in sanitation on the other. However, even a strong investment into flushing toilets would not reduce environmental pollution due to the dominance of on-site sanitation systems, but instead strongly increase water competition. Key options to reduce the nutrient load would be via optimized waste collection and investment in dry or low-flush toilets. The latter seems also appropriate for the city to meet the water and sanitation Millennium Development Goals (MDGs) without increasing water shortages in toilet connected households. 相似文献
958.
Lucia Aidos Mauro Vasconi Francesco Abbate Luisa M. P. Valente Marco Lanfranchi Alessia Di Giancamillo 《Aquaculture Research》2019,50(2):588-598
This study evaluated the effects of rearing density on muscle growth and development in Siberian sturgeon (Acipenser baerii) larvae. Three different stocking densities were tested: low (LD, 30 larvae/l), mid (MD, 80 larvae/l) and high (HD, 150 larvae/l) in a recirculating aquaculture system. Larvae were sampled at hatching (T0), schooling (T1) and complete yolk‐sac absorption (T2) stage and were weighed and processed for muscle tissue histometrical analyses and for qualitative morphological study analyses; fatty acid profile was also determined by Gas Chromatography—Flame Ionization Detector analysis. Low‐density larvae presented a higher weight than MD or HD at T2 (p < 0.05). Histometrical analysis revealed that total muscle area was similar at T1 and T2, but higher than T0, while it was lower at HD at schooling (p < 0.05). The fatty acid profile revealed no differences between densities while, during development, there was a selective consumption: sparing or increasing of essential fatty acids to the detriment of their precursors. Our study suggests that lower densities appear to be more suitable to rear Siberian sturgeon in this particular stage of development. Indeed, larvae reared at the lower density were heavier and longer while larvae reared at the higher density showed lower muscle proliferation rate. As a consequence, LD larvae may exert an increase of potential growth at a mid‐long term. 相似文献
959.
Emilie Laurin Ian A. Gardner Andrea Peña Marco Rozas-Serri Jorge Gayosa Joaquin Neumann Heise Fernando O. Mardones 《Journal of fish diseases》2020,43(10):1167-1175
Early detection of piscirickettsiosis is an important purpose of government- and industry-based surveillance for the disease in Atlantic salmon farms in Chile. Real-time qPCRs are currently used for surveillance because bacterial isolation is inadequately sensitive or rapid enough for routine use. Since no perfect tests exist, we used Bayesian latent class models to estimate diagnostic sensitivity (DSe) and specificity (DSp) of qPCR and culture using separate two-test, single-population models for three farms (n = 148, 151, 44). Informative priors were used for DSp (culture (beta(999,1); qPCR (beta(98,2)), and flat priors (beta 1,1) for DSe and prevalence. Models were run for liver and kidney tissues combined and separately, based on the presence of selected gross-pathological signs. Across all models, qPCR DSe was 5- to 30-fold greater than for culture. Combined-tissue qPCR median DSe was highest in Farm 3 (sampled during P. salmonis outbreak (DSe = 97.6%)) versus Farm 1 (DSe = 85.6%) or Farm 2 (DSe = 83.5%), both sampled before clinical disease. Median DSe of qPCR was similar for liver and kidney, but higher when gross-pathological signs were evident at necropsy. High DSe and DSp and rapid turnaround-time indicate that the qPCR is fit for surveillance programmes and diagnosis during an outbreak. Targeted testing of salmon with gross-pathological signs can enhance DSe. 相似文献
960.
Benedetto Sicuro Paola Badino Franco Daprà Francesco Gai Marco Galloni Rosangela Odore Giovanni Battista Palmegiano Elisabetta Macchi 《Aquaculture International》2010,18(3):415-431
Olive mill vegetation water (VW) is an olive oil by-product rich in polyphenols has powerful antioxidant effects. In light
of the interest on the research of novel natural antioxidants to use in fish feed, the aim of this research was to use VW
as a potential substitute for artificial antioxidants in rainbow trout diet as well as checking its effects on the blood chemistry
and digestive organ physiology of the fish. The experimental plan was monofactorial, balanced (4 × 3) and the experimental
factor considered was the fish diet. Diets were isoproteic (CP 40%) and isoenergetic (18 MJ kg−1 DM) with two inclusion levels of VW (1 and 5%: VW1 and VW5) tested against a control diet. A feeding trial was performed
on quadruplicate groups of 200 fish (mean body weight: 44.2 g) fed experimental diets for 94 days. At the end of the trial,
the growth performance traits were determined and sampling of blood and different tissues (brain, ovary, stomach, liver, and
intestine) were carried out for haematology, endocrinology, histology, and digestive enzyme analysis. The main results of
the present experimentation are that VW inclusion in rainbow trout feed slightly affects the productive traits and blood chemistry,
while the histological structure of digestive organs and digestive enzyme physiology were not affected. 相似文献