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21.
- 1 This paper lists 171 freshwater macroinvertebrate taxa from Tenerife (excluding chironomids) based on this study and other published information. Canarian endemism and a Mediterranean origin are dominant features in the data set. At least 14 species are Tenerife endemics. Endemism is especially high in the Diptera, Trichoptera and Coleoptera.
- 2 Extensive investigations were carried out at 57 sites in six different habitat categories and from at least two seasons. The most species-rich habitats were those with permanently running water, a biotope that is rare and diminishing in Tenerife.
- 3 The principal threat to freshwater environments is an increase in human exploitation of the water resources, which, if it is not moderated, will cause extinctions in the near future. Taxa that do not favour man-made canals are especially at risk—a risk that is increased by the small number of populations. These include the Canarian endemics Wormaldia tagananana, Tinodes canariensis (Trichoptera), Dixa tetrica (Diptera) and Baetis pseudorhodani (Ephemeroptera). Thirty-nine species were found at five or fewer sites.
- 4 Some species can survive in intermittent streams, although we found less than half of the taxa present in this habitat, indicating the extent of the diversity reductions that might be expected to follow the drying up of permanent streams.
- 5 Species living in the thin film of water in the madicolous habitats are similarly at risk. Three Canarian endemics were found exclusively in this habitat: Hydrotarsus pilosus, Limnebius punctatus (Coleoptera) and Satchelliella binunciolata (Diptera).
- 6 As a first step, protective measures are proposed for five of the most species-rich streams. If these were to be implemented, they would make a significant contribution towards maintaining biodiversity in the fresh waters of Tenerife.
22.
摄食促进剂对对虾生长的影响 总被引:5,自引:0,他引:5
IntroductionMeasures to assure that all feed offered to animals in commercial operation is consumed and to reduceformulated feed waste pollution,have been considered as some of the most relevant for lowering productioncosts in aquaculture.Considering the importance of chemical stimulant in development of the crustacean lifecircle,it is logical to assume that by adding attractants to the feed,the animal would rapidly find potentialfeed and ingest it.Additionally,measures involving the incorpora… 相似文献
23.
Ragnhild J Bager Egle Kudirkiene Isabelle da Piedade Torsten Seemann Tine K Nielsen Susanne E Pors Andreas H Mattsson John D Boyce Ben Adler Anders M Bojesen 《Veterinary research》2014,45(1)
The Gram-negative bacterium Gallibacterium anatis is a major cause of salpingitis and peritonitis in commercial egg-layers, leading to reduced egg production and increased mortality. Unfortunately, widespread multidrug resistance and antigenic diversity makes it difficult to control infections and novel prevention strategies are urgently needed. In this study, a pan-genomic reverse vaccinology (RV) approach was used to identify potential vaccine candidates. Firstly, the genomes of 10 selected Gallibacterium strains were analyzed and proteins selected on the following criteria; predicted surface-exposure or secretion, none or one transmembrane helix (TMH), and presence in six or more of the 10 genomes. In total, 42 proteins were selected. The genes encoding 27 of these proteins were successfully cloned in Escherichia coli and the proteins expressed and purified. To reduce the number of vaccine candidates for in vivo testing, each of the purified recombinant proteins was screened by ELISA for their ability to elicit a significant serological response with serum from chickens that had been infected with G. anatis. Additionally, an in silico prediction of the protective potential was carried out based on a protein property prediction method. Of the 27 proteins, two novel putative immunogens were identified; Gab_1309 and Gab_2312. Moreover, three previously characterized virulence factors; GtxA, FlfA and Gab_2156, were identified. Thus, by combining the pan-genomic RV approach with subsequent in vitro and in silico screening, we have narrowed down the pan-proteome of G. anatis to five vaccine candidates. Importantly, preliminary immunization trials indicated an in vivo protective potential of GtxA-N, FlfA and Gab_1309.
Electronic supplementary material
The online version of this article (doi:10.1186/s13567-014-0080-0) contains supplementary material, which is available to authorized users. 相似文献24.
关注林权:中国集体林政策研究国际研讨会综述 总被引:1,自引:0,他引:1
公共资源面对的挑战、风险与机遇受到国际社会的关注。文章以“国际公共资源研究协会第十届大会”为背景,对中国集体林研究课题的成果、相关国际会议内容及专家发言作了介绍。研究成果主要形成8个专题报告,国际会议分“中国集体林政策和法律框架的总体回顾”和“中国集体林与生态保护、公司 社区模式”两个部分展开,并形成了5点结论。 相似文献
25.
Anders Berglund Olof Broman Johan Oja Anders Grönlund 《Scandinavian Journal of Forest Research》2015,30(1):87-97
To define new grading rules, or to customize the ones in use in a rule-based automatic grading (RBAG) system of boards, is a time-consuming job for a sawmill engineer. This has the effect that changes are rarely made. The objective of this study was to continue the development of a method that replaces the calibration of grading rule settings by a holistic-subjective automatic grading, using multivariate models. The objective was also to investigate if this approach can improve sawmill profitability and at the same time have a satisfied customer. For the study, 323 Scots pine (Pinus sylvestris L.) boards were manually graded according to the preferences of an important customer. That is, a customer that regularly purchases significant volumes of sawn timber. This manual grading was seen as reference grading in this work. The same boards were also scanned and graded by a RBAG system, calibrated for the same customer. Multivariate models for prediction of board grade based on aggregated knot variables, obtained from the scanning, were calibrated using partial least squares regression. The results show that prediction of board grades by the multivariate models were more correct, with respect to the manual grading, than the grading by the RBAG system. The prediction of board grades based on multivariate models resulted in 76–87% of the boards graded correctly, according to the manual grading, while the corresponding number was 63% for the RBAG system. 相似文献
26.
27.
Mikael Jönsson Lynn Ranåker P. Anders Nilsson Christer Brönmark 《Ecology of Freshwater Fish》2012,21(3):461-468
Abstract – Fish, which are generally visual foragers, experiences reduced reaction distance in visually degraded environments, which has consequences for encounter rates with prey. Small prey is detected at shorter distances than larger prey, and piscivores are therefore predicted to be more strongly affected by visual degradation. In experiments, roach (Rutilus rutilus) were fed two plankton prey types and pike (Esox lucius) were fed Daphnia and larval roach, in clear water, algal turbid water and water coloured brown by dissolved organic matter (DOM). Planktivorous foraging in roach was not affected by visual degradation, while pike foraging on both Daphnia and larval roach was. Pike showed increased reaction distance to Daphnia in visually degraded water, while it was severely reduced with roach as prey even if the visual range was not reduced below pike reaction distances in clear water. Pike foraging on Daphnia was not affected, but when foraging on roach, the reduced search efficiency was counteracted by increased attack rates. However, there was no increase in movement and no difference between turbid and DOM treatments. Effects on piscivores will likely become more pronounced at later life stages as prey size and the reliance on long‐distance detection increases at the same time as changing climatic conditions may further deteriorate the visual conditions in future. 相似文献
28.
The release of CO2 by soil microorganisms after the addition of nitrogen and glucose in excess and calibration additions of phosphorus has successfully
been used to assess microbial available P, assuming the native soil P pool is then limiting respiration. However, in P-fixing
soils and soils with high P content, carbon can be exhausted before the available soil P pool. It is not possible to simply
increase the amount of glucose as then the glucose concentration would be lethal for microorganisms. A modified method was
tested where soil is mixed with perlite. It was hypothesised that perlite, having a high water holding capacity, would dilute
the concentration of glucose, while maintaining the bioavailability of added nutrients, thus avoiding carbon limitation. Factorial
combinations of amount of soil and perlite (both adjusted to −25 kPa water potential) were tested to examine if perlite as
such had any effect on the respiration. Five tropical soil samples with a sharp gradient in P availability and one N-limited
compost material were used. The method successfully reduced the risk of carbon limitation. Microbial indices, such as basal
respiration, substrate-induced respiration and maximum P-limited respiration, were directly proportional to the amount of
soil in the experiments but unrelated to the amount of perlite, showing that perlite did not affect microbial measurements. 相似文献
29.
Sander Bruun Bo Stenberg Jon Gudmundsson Lars S. Jensen Jesper Luxhøi Anders Pedersen 《Soil biology & biochemistry》2005,37(12):2283-2296
Prediction of carbon (C) and nitrogen (N) mineralization patterns of plant litter is desirable for both agronomic and environmental reasons. Near infrared reflectance (NIR) spectroscopy has recently been introduced in decomposition studies to characterize biochemical composition. The purpose of the current study was to use empirical techniques to predict C and N mineralization patterns of a wide range of plant materials incubated under controlled temperature and moisture conditions. We hypothesized that the richness of information in the NIR spectra would considerably improve predictions compared to traditional stepwise chemical digestion (SCD) or C/N ratios. Initially, we fitted a number of empirical functions to the observed C and N mineralization patterns. The best functions fitted with R2=0.990 and 0.949 to C and N, respectively. The fractions of C and N mineralized at different points in time were then either predicted directly with regression functions or indirectly by prediction of the parameters of the empirical functions fitted to incubation data. In both cases, partial least squares (PLS) regressions were used and predictions were validated by cross-validations. We found that the NIR spectra (best R2=0.925) were able to predict C mineralization patterns marginally better than the SCD fractions (best R2=0.911), but considerably better than the C/N ratios (best R2=0.851). In contrast, N mineralization was better predicted by SCD fractions (best R2=0.533) than the C/N ratio (best R2=0.497), which was better than NIR predictions (best R2=0.446). Although the predictions with the NIR spectra were only slightly better for C and worse for N mineralization compared to SCD fractions, NIR spectroscopy still holds advantages, as it is a much less laborious and cheaper analytical method. Furthermore, exploration of the applications of NIR spectroscopy in decomposition studies has only just begun, and offers new ways to gain insights into the decomposition process. 相似文献
30.