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881.
882.
In plants, reactive oxygen species (ROS) are short-lived molecules produced through various cellular mechanisms in response
to biotic and abiotic stimuli. ROS function as second messengers for hormone signaling, development, oxygen deprivation, programmed
cell death, and plant–pathogen interactions. Recent research on ROS-mediated responses has produced stimulating findings such
as the specific sources of ROS production, molecular elements that work in ROS-mediated signaling and homeostasis, and a ROS-regulated
gene network (Neill et al., Curr Opin Plant Biol 5:388–395, 2002a; Apel and Hirt, Annu Rev Plant Biol 55:373–399, 2004; Mittler et al., Trends Plant Sci 9:490–498, 2004; Mori and Schroeder, Plant Physiol 135:702–708, 2004; Kwak et al., Plant Physiol 141:323–329, 2006; Torres et al., Plant Physiol 141:373–378, 2006; Miller et al., Physiol Plant 133:481–489, 2008). In this review, we highlight new discoveries in ROS-mediated abscisic acid (ABA) signaling.
Drs. Daeshik Cho and June M. Kwak are the corresponding authors for this paper. 相似文献
883.
Sun G Hagooly A Xu J Nyström AM Li Z Rossin R Moore DA Wooley KL Welch MJ 《Biomacromolecules》2008,9(7):1997-2006
The in vivo behavior of shell cross-linked knedel-like (SCK) nanoparticles is shown to be tunable via a straightforward and versatile process that advances SCKs as attractive nanoscale carriers in the field of nanomedicine. Tuning of the pharmacokinetics was accomplished by grafting varied numbers of methoxy-terminated poly(ethylene glycol) (mPEG) chains to the amphiphilic block copolymer precursors, together with chelators for the radioactive tracer and therapeutic agent (64)Cu, followed by self-assembly into block copolymer micelles and chemical cross-linking throughout the shell regions. (64)Cu-radiolabeling was then performed to evaluate the SCKs in vivo by means of biodistribution experiments and positron emission tomography (PET). It was found that the blood retention of PEGylated SCKs could be tuned, depending on the mPEG grafting density and the nanoparticle surface properties. A semiquantitative model of the density of mPEG surface coverage as a function of in vivo behavior was applied to enhance the understanding of this system. 相似文献
884.
To address the question whether the abundance of an invasive species can be explained by physical and chemical properties
of the invaded ecosystems, we gathered density data of invasive zebra mussels and the physical and chemical data of ecosystems
they invaded. We assembled published data from 55 European and 13 North American lakes and developed a model for zebra mussel
density using a generalized additive model (GAM) approach. Our model revealed that the joint effect of surface area, total
phosphorus and calcium concentrations explained 62% of the variation in Dreissena density. Our study indicates that large and less productive North American lakes can support larger local populations of
zebra mussels. Our results suggest that the proliferation of an exotic species in an area can partially be explained by physical
and chemical properties of the recipient environment. 相似文献
885.
Khaled M. Abdel Rahman Marek Barta Ľudovít Cagáň 《Central European Journal of Biology》2010,5(4):472-480
We tested the combined effect of the fungus Beauveria bassiana and the microsporidium Nosema pyrausta on the European corn borer larvae, Ostrinia nubilalis, in the laboratory. The first instar of O. nubilalis larvae was the most sensitive to the B. bassiana infection followed by the fifth, second, third, and fourth instar (LC50s were 4.91, 6.67, 7.13, 9.15, and 6.51 × 105 conidia/ml for the first to fifth instars, respectively). Mortality of each instar increases positively with concentration
of conidia. When B. bassiana and N. pyrausta were used in combination, mortality increased significantly in all instars. Relative to the B. bassiana treatment alone, the B. bassiana + N. pyrausta treatment decreased the LC50s by 42.16%, 37.63%, 21.60%, 27.11%, and 33.95% for the first to fifth instars, respectively. The combined effects of the
two pathogens were mostly additive. However, at the two highest concentrations the pathogens interacted synergistically in
the first and second instar. Individuals that survived the B. bassiana and B. bassiana + N. pyrausta treatments and developed into adults had significantly shorter lifespans and females oviposited fewer eggs than non-exposed
insects. The effects on the longevity and the egg production were most pronounced at high concentration of B. bassiana conidia. 相似文献
886.
Deborah Schmitz Jan W. Robering Volker Weisbach Andreas Arkudas Ingo Ludolph Raymund E. Horch Anja M. Boos Annika KengelbachWeigand 《Journal of cellular and molecular medicine》2022,26(16):4463
Adipose‐derived stromal cells (ADSC) are increasingly used in clinical applications due to their regenerative capabilities. However, ADSC therapies show variable results. This study analysed the effects of specific factors of ex‐obese patients on ADSC functions. ADSC were harvested from abdominal tissues (N = 20) after massive weight loss. Patients were grouped according to age, sex, current and maximum body mass index (BMI), BMI difference, weight loss method, smoking and infection at the surgical site. ADSC surface markers, viability, migration, transmigration, sprouting, differentiation potential, cytokine secretion, telomere length and mtDNA copy number were analysed. All ADSC expressed CD73, CD90, CD105, while functional properties differed significantly among patients. A high BMI difference due to massive weight loss was negatively correlated with ADSC proliferation, migration and transmigration, while age, sex or weight loss method had a smaller effect. ADSC from female and younger donors and individuals after weight loss by increase of exercise and diet change had a higher activity. Telomere length, mtDNA copy number, differentiation potential and the secretome did not correlate with patient factors or cell function. Therefore, we suggest that factors such as age, sex, increase of exercise and especially weight loss should be considered for patient selection and planning of regenerative therapies. 相似文献
887.
James S. Wakeley Michael P. Guilfoyle Terry J. Antrobus Richard A. Fischer Wylie C. BarrowJr. Paul B. Hamel 《Wetlands Ecology and Management》2007,15(5):417-439
We used an ordination approach to identify factors important to the organization of breeding bird communities in three floodplains:
Cache River, Arkansas (AR), Iatt Creek, Louisiana (LA), and the Coosawhatchie River, South Carolina (SC), USA. We used 5-min
point counts to sample birds in each study area each spring from 1995 to 1998, and measured ground-surface elevations and
a suite of other habitat variables to investigate bird distributions and community characteristics in relation to important
environmental gradients. In both AR and SC, the average number of Neotropical migrant species detected was lowest in semipermanently
flooded Nyssa aquatica Linnaeus habitats and greatest in the highest elevation floodplain zone. Melanerpes carolinus Linnaeus, Protonotaria citrea Boddaert, Quiscalus quiscula Linnaeus, and other species were more abundant in N. aquatica habitats, whereas Wilsonia citrina Boddaert, Oporornis formosus Wilson, Vireo griseus Boddaert, and others were more abundant in drier floodplain zones. In LA, there were no significant differences in community
metrics or bird species abundances among forest types. Canonical correspondence analyses revealed that structural development
of understory vegetation was the most important factor affecting bird distributions in all three study areas; however, potential
causes of these structural gradients differed. In AR and SC, differences in habitat structure were related to the hydrologic
gradient, as indexed by ground-surface elevation. In LA, structural variations were related mainly to the frequency of canopy
gaps. Thus, bird communities in all three areas appeared to be organized primarily in response to repeated localized disturbance.
Our results suggest that regular disturbance due to flooding plays an important role in structuring breeding bird communities
in floodplains subject to prolonged inundation, whereas other agents of disturbance (e.g., canopy gaps) may be more important
in headwater systems subject to only short-duration flooding. Management for avian community integrity in these systems should
strive to maintain forest zonation and natural disturbance regimes. 相似文献
888.
889.
Biological availability and humic properties of dissolved organic carbon in Lake Balaton (Hungary) 总被引:1,自引:0,他引:1
The nursery role of the Mondego estuary for marine fish species was studied between June 2003 and May 2004. The spatial and
temporal distribution and abundance patterns of 0-group Dicentrarchus
labrax (Linnaeus, 1758), Platichthys
flesus (Linnaeus, 1758) and Solea solea (Linnaeus, 1758) were analyzed based on monthly sampling surveys in five stations along the estuarine gradient. Fishing took
place during the night at low water of spring tides, using a 2 m beam trawl. The spatial patterns of estuarine colonization
were different according to species. D. labrax showed a wider distribution, but the main nursery ground was the same as for S. solea. Highest densities of S. solea juveniles were found in oligohaline areas, with muddy bottoms and high benthic invertebrates availability, while P. flesus occurred mainly in the sandy uppermost areas. D. labrax was found in both these areas. Fish abundance in the estuary mainly reflected seasonal changes. 相似文献
890.
Mikael Gyllström Thomas Lakowitz Christer Brönmark Lars-Anders Hansson 《Ecosystems》2008,11(7):1120-1132
In an experimental study we assessed if benthic bioturbating invertebrates affect the recruitment (hatching) of zooplankton
from the sediment, and if this effect persists as differences in the zooplankton community in the water column, that is, if
bioturbation quantitatively stimulates benthic–pelagic coupling. We investigated the effects of four different benthic invertebrates
(Asellus aquaticus, Chironomus plumosus, Tubifex tubifex in the presence or absence of the predator Sialis lutaria). In total, 45 zooplankton taxa hatched from the sediment and the hatching success of some of these was dependent on the
species identity of the bioturbating invertebrate. The predator Sialis reduced the abundance of all three invertebrate species, but tended to positively influence the zooplankton recruitment rates,
possibly through increasing the activity of the bioturbating invertebrates. The most striking effect of bioturbation on the
hatching and pelagic zooplankton community properties was that, on average, 11% more species hatched in the Asellus treatment than in any other treatment. This was also mirrored in the zooplankton water column community where, on average,
7% more species established a viable population in treatments with Asellus as bioturbator. In a complementary field survey, Asellus was more common in littoral than in profundal sediments. Because Asellus strongly affected recruitment of zooplankton in our experiment, we argue that bioturbation may partly explain why recruitment
of resting stages of both phyto- and zooplankton is generally higher in littoral than in profundal areas. 相似文献