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241.
Enrique Jurado Joel Flores Anton G. Endress Mercedes Flores Eduardo Estrada Marisela Pando 《Restoration Ecology》2006,14(2):204-209
Clearing native vegetation to increase the amount of land available for agriculture in northeastern Mexico has left remnants ranging in size from fragments of continuous vegetation to isolated individual trees. These provide valuable opportunities for restoring larger areas of native vegetation. We explored whether fragmentation of Tamaulipan thornscrub affects the removal of seeds from 12 woody species that encompass a range of sizes and dispersal mechanisms. We tested whether (1) seed removal rates under isolated trees were higher than under continuous vegetation; (2) dispersal structures, such as fleshy pericarps, made some seeds more attractive to seed removers; and (3) microenvironmental variation affected seed removal rates. Seeds were placed under canopies of Texas ebony (Ebenopsis ebano) and Mesquite trees (Prosopis laevigata). Seed removal trials were conducted three times, each trial lasting 30 days. Most seeds were removed in all trials by the end of one month. Seed removal rate was slower under isolated trees. In general, fleshy fruits were removed faster than other fruits; whole fruits and fleshy tissue were removed faster than depulped seeds. In species with fleshy pericarps, acid washing of seeds, to simulate seeds processed in the digestive tract of dispersers, reduced the seed removal rates, suggesting that it would be a good pre‐treatment for restoration efforts. 相似文献
242.
JORGE DOÑA JAIME POTTI IVÁN DE LA HERA GUILLERMO BLANCO OSCAR FRÍAS ROGER JOVANI 《Ecological Entomology》2017,42(4):492-499
1. The consequences of symbiont transmission strategies are better understood than their adaptive causes. 2. Feather mites are permanent ectosymbionts of birds assumed to be transmitted mainly vertically from parents to offspring. The transmission of Proctophyllodes doleophyes Gaud (Astigmata, Proctophyllodidae) was studied in two European populations of pied flycatchers, Ficedula hypoleuca Pallas (Passeriformes, Muscicapidae). 3. The vertical transmission of this mite species is demonstrated here with an acaricide experiment. This study also compared (for two distant populations during 4 years) patterns in reductions in mite intensity in adult birds, from egg incubation to chick‐rearing periods, with the predictions of three hypotheses on how host survival prospects and mite intraspecific competition might drive feather mites' transmission strategy. 4. The results are in agreement with previous studies and show that feather mites transmit massively from parents to chicks. 5. The magnitude of the transmission was closer to that predicted by the hypothesis based on intraspecific competition, while a bet‐hedging strategy is also partially supported. 相似文献
243.
G. Becerra Jurado M. Callanan M. Gioria J.-R. Baars R. Harrington M. Kelly-Quinn 《Hydrobiologia》2009,634(1):153-165
Eutrophication still continues to be an issue of major concern for the protection of water quality, and accordingly, the European
Union Water Framework Directive has set a minimum target for all waters where “good status” is defined as a slight departure
from the biological community which would be expected in conditions of minimal anthropogenic impact. The use of constructed
ponds for wastewater treatment aimed at achieving this target has shown to be an effective alternative to conventional systems
in the farm landscape. Their applicability in these areas is of great interest since these ponds have the added potential
to combine their wastewater treatment properties with that of biodiversity enhancement. This article focuses on exploring
the community structure of both natural and constructed ponds used for wastewater treatment and the driving environmental
factors. A total of 15 constructed and 5 natural ponds were sampled for aquatic macroinvertebrates and hydrochemistry in spring
and summer 2006. Results showed that the most important factors responsible for the differences in the community structure
between these two types of ponds were pH, vegetation structure and pollution levels. These gradients helped to structure a
large proportion of the communities with some taxa being associated with the constructed ponds. These results highlight the
potential contribution of constructed ponds used for wastewater treatment to the landscape biodiversity. The present findings
also open the possibility for a more integrated management of water quality and biodiversity enhancement in farmland areas.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: B. Oertli, R. Cereghino, A. Hull & R. Miracle
Pond Conservation: From Science to Practice. 3rd Conference of the European Pond Conservation Network, Valencia, Spain, 14–16
May 2008 相似文献
244.
Background
Colorants derived from natural sources look set to overtake synthetic colorants in market value as manufacturers continue to meet the rising demand for clean label ingredients – particularly in food applications. Many ascomycetous fungi naturally synthesize and secrete pigments and thus provide readily available additional and/or alternative sources of natural colorants that are independent of agro-climatic conditions. With an appropriately selected fungus; using in particular chemotaxonomy as a guide, the fungal natural colorants could be produced in high yields by using the optimized cultivation technology. This approach could secure efficient production of pigments avoiding use of genetic manipulation. 相似文献245.
Susana Jurado Natalia Garcia‐Giralt Adolfo Díez‐Pérez Pedro Esbrit Guy Yoskovitz Lídia Agueda Roser Urreizti Lluís Pérez‐Edo Guillem Saló Leonardo Mellibovsky Susana Balcells Daniel Grinberg Xavier Nogués 《Journal of cellular biochemistry》2010,110(2):304-310
The RANKL/RANK/OPG pathway is essential for bone remodeling regulation. Many hormones and cytokines are involved in regulating gene expression in most of the pathway components. Moreover, any deregulation of this pathway can alter bone metabolism, resulting in loss or gain of bone mass. Whether osteoblasts from osteoporotic and nonosteoporotic patients respond differently to cytokines is unknown. The aim of this study was to compare the effect of interleukin (IL)‐1β, proftaglandin E2 (PGE2), and transforming growth factor‐β1 (TGF‐β1) treatments on OPG and RANKL gene expression in normal (n = 11) and osteoporotic (n = 8) primary osteoblasts. OPG and RANKL mRNA levels of primary human osteoblastic (hOB) cell cultures were assessed by real‐time PCR. In all cultures, OPG mRNA increased significantly in response to IL‐1β treatment and decreased in response to TGF‐β1 whereas PGE2 treatment had no effect. RANKL mRNA levels were significantly increased by all treatments. Differences in OPG and RANKL responses were observed between osteoporotic and nonosteoporotic hOB: in osteoporotic hOB, the OPG response to IL‐1β treatment was up to three times lower (P = 0.009), whereas that of RANKL response to TGF‐β1 was five times higher (P = 0.002) after 8 h of treatment, as compared with those in nonosteoporotic hOBs. In conclusion, osteoporotic hOB cells showed an anomalous response under cytokine stimulation, consistent with an enhanced osteoclastogenesis resulting in high levels of bone resorption. J. Cell. Biochem. 110: 304–310, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
246.
Andy?Pang Andrew?D?Smith Paulo?AS?Nuin Elisabeth?RM?TillierEmail author 《BMC bioinformatics》2005,6(1):236
Background
General protein evolution models help determine the baseline expectations for the evolution of sequences, and they have been extensively useful in sequence analysis and for the computer simulation of artificial sequence data sets. 相似文献247.
248.
Destruction of lysine by nonreducing sugars 总被引:1,自引:0,他引:1
249.
250.
A new method for the enrichment of cultures of Serratia marcescens for auxotrophic mutants has been developed. The method is based on the formation of filaments by growing cells in minimal medium M70 containing azthreonam. Auxotrophic mutants unable to grow in M70 do not form filaments. Mutants are collected from the culture by filtration. 相似文献