Gene expression pattern of digestive and antioxidant enzymes during the larval development of reared Atlantic bluefin tuna (ABFT), Thunnus thynnus L.          下载免费PDF全文

David Mazurais  Denis Covès  Nikos Papandroulakis  Aurelio Ortega  Elisabeth Desbruyeres  Christine Huelvan  Marie Madeleine Le Gall  Fernando de la Gándara  Chantal Louise Cahu 《Aquaculture Research》2015,46(10):2323-2331

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OCCURRENCE OF INDUCIBLE NITRIC OXIDE SYNTHASE IMMUNOREACTIVE MATERIAL IN THE RETINA OF THE CLAWED FROG,Xenopus laevis     

黄世乐  陈祖义  Anton Hermann 《核农学报》1998,12(5):0-0

借助Ⅱ和Ⅲ型一氧化氮合成酶（ＮＯＳ）特异性抗体对成年爪蛙（Ｘｅｎｏｐｕｓｌａｅｖｉｓ）视网膜中含ＮＯＳ的结构进行了免疫细胞化学定位研究。发现视杆和视锥细胞的视网膜杆、少数神经节细胞和无足细胞的细胞体均含有ＮＯＳⅡ免疫反应物质,缪勒细胞呈现强的ＮＯＳⅡ免疫反应性,外神经丛层的神经突起亦含强的ＮＯＳⅡ免疫反应性。在视网膜的细胞结构中,未见ＮＯＳⅢ免疫反应性。该结果暗示由ＮＯＳⅡ产生的一氧化氮可能参与视觉传导的调节。  相似文献   

Extraction and colorimetric determination of azadirachtin-related limonoids in neem seed kernel.     

J Dai  V A Yaylayan  G S Raghavan  J R Parè 《Journal of agricultural and food chemistry》1999,47(9):3738-3742

A colorimetric method was developed for the determination of total azadirachtin-related limonoids (AZRL) in neem seed kernel extracts. The method employed acidified vanillin solution in methanol for the colorization of the standard azadirachtin or neem seed kernel extracts in dichloromethane. Through the investigation of various factors influencing the sensitivity of detection, such as the concentration of vanillin, acid, and the time required for the formation of color, optimum conditions were selected to perform the assay. Under the optimum conditions, a good linearity was found between the absorbance at 577 nm and the concentration of standard azadirachtin solution in the range of 0.01-0.10 mg/mL. In addition, different extraction procedures were evaluated using the vanillin assay. The HPLC analysis of the extracts indicated that if the extractions were performed in methanol followed by partitioning in dichloromethane, approximately 50% of the value determined by the vanillin assay represents azadirachtin content.  相似文献   

Earthworm populations and growth rates related to long-term crop residue and tillage management     

Nikita S. Eriksen-Hamel  Alicia B. Speratti  Joann K. Whalen  Anne Lgre  Chandra A. Madramootoo 《Soil & Tillage Research》2009,104(2):311-316

Conventional tillage creates soil physical conditions that may restrict earthworm movement and accelerate crop residue decomposition, thus reducing the food supply for earthworms. These negative impacts may be alleviated by retaining crop residues in agroecosystems. The objective of this study was to determine the effects of various tillage and crop residue management practices on earthworm populations in the field and earthworm growth under controlled conditions. Population assessments were conducted at two long-term (15+ years) experimental sites in Québec, Canada with three tillage systems: moldboard plow/disk harrow (CT), chisel plow or disk harrow (RT) and no tillage (NT), as well as two levels of crop residue inputs (high and low). Earthworm growth was assessed in intact soil cores from both sites. In the field, earthworm populations and biomass were greater with long-term NT than CT and RT practices, but not affected by crop residue management. Laboratory growth rates of Aporrectodea turgida (Eisen) in intact soil cores were affected by tillage and residue inputs, and were positively correlated with the soil organic C pool, suggesting that tillage and residue management practices that increase the soil organic C pool provide more organic substrates for earthworm growth. The highest earthworm growth rates were in soils from RT plots with high residue input, which differed from the response of earthworm populations to tillage and residue management treatments in the field. Our results suggest that tillage-induced disturbance probably has a greater impact than food availability on earthworm populations in cool, humid agroecosystems.  相似文献   

Phenylpyrazoles impact on Folsomia candida (Collembola)     

Anglique San Miguel  Muriel Raveton  Guy Lemprire  Patrick Ravanel 《Soil biology & biochemistry》2008,40(9):2351

Effects of the broad-spectrum insecticide fipronil were investigated on a non-target insect living in the soil, the springtail Folsomia candida Willem. Fipronil induced a significant reduction in juvenile production (PNEC = 250 μg kg⁻¹ dry soil), which seemed to be linked with an impact on the first stages of springtail development: juveniles and 7-day-old adults. These young organisms have a thinner integument, a smaller mass body and a weaker detoxification efficiency and were more sensitive than adults (14 days old) to fipronil and phenylpyrazole derivatives. Contact toxicity for juveniles was measured (LC₅₀(96 h)) giving the following values: fipronil, 450 μg l⁻¹; sulfone-fipronil, 430 μg l⁻¹; sulfide-fipronil, 160 μg l⁻¹. F. candida organisms were able to avoid contaminated food because phenylpyrazoles decreased food appetency. However, F. candida could bioaccumulate fipronil through trans-tegumental penetration (BAF_96 h = 160) and its high biotransformation rate inside springtail bodies (1 ng fipronil metabolized day⁻¹ individual⁻¹) was suspected to increase this process. Under natural conditions, phenylpyrazoles risk assessment on springtails seems to be weak due to their capacity of avoiding high contaminated zones and their biochemical tolerance to this class of insecticides.  相似文献   

tau‐Fluvalinate and other pesticide residues in honey bees before overwintering     

Tomas Erban  Marta Vaclavikova  Daniela Tomesova  Tatana Halesova  Jan Hubert 《Pest management science》2019,75(12):3245-3251

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Development of two telemetry-based systems for monitoring the feeding behaviour of Atlantic salmon (Salmo salar L.) in aquaculture sea-cages     

Martin Føre  Jo Arve AlfredsenAage Gronningsater 《Computers and Electronics in Agriculture》2011,76(2):240-251

Two novel acoustic transmitter tags intended to reflect feeding behaviours in farmed Atlantic salmon (Salmo salar L.) were developed and tested in this study. Using information from the literature and video recordings of feeding salmon, measurements of swimming depth and motion (acceleration) were identified as two promising sensing principles on which to base the tag development. Video footage and laboratory studies were used to develop corresponding algorithms that translated depth and acceleration measurements into compound parameters reflecting the different aspects that discern feeding activity from other activities. Field tests performed in a sea-farm were used to verify the functionality of the tags, and indicated that both tag types had potential in distinguishing between feeding and non-feeding behaviour. Additionally, both depth- and acceleration-based tags were seen to have applications to fish monitoring and farm management beyond that of observing feeding in salmon, in giving recordings of the vertical swimming behaviour of fish over extended periods of time as well as indications of the activity changes of fish due to external influences. These results suggest that fish telemetry using sensor-based transmitter tags could represent a useful tool in future fish farm management.  相似文献   

Larval traits of the Caribbean amphidromous goby Sicydium punctatum (Gobioidei: Sicydiinae) in Guadeloupe          下载免费PDF全文

Léa Lejeune  Hélène Tabouret  Laura Taillebois  Dominique Monti  Philippe Keith 《Ecology of Freshwater Fish》2016,25(2):272-280

Amphidromous fish are the biggest contributor to the diversity of fish communities in river systems of Caribbean islands. Among them, Sicydium punctatum Perugia, 1896, which is endemic to the West Indies, represents the vast majority of fish in these rivers. The otolith microstructure and the biometry of S. punctatum postlarvae from Guadeloupe were investigated to explore the dispersal modalities of this species through an appreciation of the growth pattern, the pelagic larval duration (PLD) and the size‐at‐recruitment. The study was made on one cohort of 83 recruited postlarvae, fished at the Capesterre River's mouth on 2 November 2011. The mean (±SD) size‐at‐recruitment of the postlarvae was 24.6 ± 1.3 mm (range of 20.5–28.1 mm, n = 83). We found a mean (±SD) PLD of 72.2 ± 10.5 days (range of 54–101.5 days, n = 67). The growth rate estimated from the otolith increments showed a globally decreasing pattern during the marine larval phase. Growth rates at the beginning of the larval stage were significantly different between hatching periods, suggesting a relation between the hatching period and the growth rate in S. punctatum. This study adds on to the general understanding of the life cycle of S. punctatum in Guadeloupe that will help implement strategies to manage amphidromous fish populations in the Caribbean region.  相似文献   

The Sustainability of Quinoa Production in Southern Bolivia: from Misrepresentations to Questionable Solutions. Comments on Jacobsen (2011, J. Agron. Crop Sci. 197: 390–399)     

T. Winkel  H. D. Bertero  P. Bommel  J. Bourliaud  M. Chevarría Lazo  G. Cortes  P. Gasselin  S. Geerts  R. Joffre  F. Léger  B. Martinez Avisa  S. Rambal  G. Rivière  M. Tichit  J. F. Tourrand  A. Vassas Toral  J. J. Vacher  M. Vieira Pak 《Journal of Agronomy and Crop Science》2012,198(4):314-319

Reviewing the situation of quinoa production in southern Bolivia, Jacobsen (2011, J. Agron. Crop Sci. 197: 390) argues that the booming export market has a negative effect on the environment and on the home consumption of quinoa, thereby leading to an environmental disaster in the region. In view of the scarcity of scientific knowledge on the rapid social and environmental dynamics in the region, we consider that Jacobsen’s review misrepresents the situation of quinoa production in southern Bolivia. Specifically, we argue that (i) the data presented by Jacobsen (2011, J. Agron. Crop Sci. 197: 390) do not support any drop in quinoa crop yield supposed to reflect soil degradation and (ii) his demonstration regarding home consumption of quinoa is ill‐founded from both a nutritional and a cultural point of view. We suggest that the diffusion of the arguments exposed by Jacobsen (2011, J. Agron. Crop Sci. 197: 390), because of their flaws, might have strong negative impacts on those concerned with sustainable food production and fair‐trade with developing countries. We conclude that, rather than reinforced agro‐technical controls on local farmers, the rising competition in the international quinoa market requires a shift towards an ethical economy and ethical research cooperation with quinoa producers.  相似文献   

Linking the abundance of aspen with soil faunal communities and rates of belowground processes within single stands of mixed aspen–black spruce     

Jérôme Laganière  David Paré  Robert L. Bradley 《Applied soil ecology》2009,41(1):19-28

The occurrence of aspen (Populus tremuloides Michx.) patches within stands dominated by black spruce (Picea mariana Mill. BSP) has been shown to increase litter decomposition and nutrient cycling rates by improving soil physical and chemical properties. It is well known, however, that these processes are also influenced by the structure of the soil biota, but this factor has received less attention. In this study, relationships between forest floor properties and soil invertebrates were studied along black spruce–trembling aspen gradients in three stands of the eastern boreal forest of Canada. The forest floor layer of 36 plots differing in aspen basal area was sampled and analyzed to determine physical and chemical properties, the rates of decomposition of standard substrates, net N mineralization, as well as microbial basal respiration and metabolic quotient. Soil invertebrates were also collected using funnel-extraction and pitfall trapping methods. Based on redundancy analyses, we found that forest floor properties, the abundance and composition of soil invertebrates, and the rates of belowground processes changed along the spruce–aspen gradient. The increase in aspen basal area was associated with a reduction in forest floor thickness, moisture content and microbial biomass, and with an increase in the concentration of nutrients. It was also accompanied by changes in soil faunal communities, as soil invertebrates were associated with specific soil properties. In general, macroinvertebrates (i.e., Lumbricidae, Formicidae, Carabidae, Staphylinidae and Gastropoda) were related to the nutrient-rich forest floor associated with aspen, whereas microarthropods and Enchytraeidae tended to be negatively related to aspen basal area. According to mixed linear models, decomposition rates of standard substrates and net ammonification significantly increased along the spruce–aspen gradient. Given the functional significance of macroinvertebrates in soils, these results suggest that aspen favours the elaboration of a macrofaunal community, which in turn accelerates the rate of soil processes by having either direct or indirect influence on microbial activity. Moreover, this study shows that the changes in soil processes and in the biodiversity of soil organisms related to the presence of mixed stands can operate only in the immediate surroundings of a given tree species. Therefore, coarse-scale tree species mixing in a forest stand may have a different effect on soil biodiversity and soil processes than fine-scale mixing.  相似文献