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81.
Matthias Erb Ruth Gordon-Weeks Victor Flors Gemma Cama?es Ted CJ Turlings Jurriaan Ton 《Plant signaling & behavior》2009,4(7):636-638
Plants are important mediators between above- and belowground herbivores. Consequently, interactions between root and shoot defenses can have far-reaching impacts on entire food webs. We recently reported that infestation of maize roots by larvae of the beetle Diabrotica virgifera virgifera induced shoot resistance against herbivores and pathogens. Root herbivory also enhanced aboveground DIMBOA and primed for enhanced induction of chlorogenic acid, two secondary metabolites that have been associated with plant stress resistance. Interestingly, the plant hormone abscisic acid (ABA) emerged as a putative long-distance signal in the regulation of these systemic defenses. In this addendum, we have investigated the role of root-derived ABA in aboveground regulation of DIMBOA and the phenolic compounds chlorogenic acid, caffeic and ferulic acid. Furthermore, we discuss the relevance of ABA in relation to defense against the leaf herbivore Spodoptera littoralis. Soil-drench treatment with ABA mimicked root herbivore-induced accumulation of DIMBOA in the leaves. Similarly, ABA mimicked aboveground priming of chlorogenic acid production, causing augmented induction of this compound after subsequent shoot attack by S. littoralis caterpillars. These findings confirm our notion that ABA acts as an important signal in the regulation of aboveground defenses during belowground herbivory. However, based on our previous finding that ABA alone is not sufficient to trigger aboveground resistance against S. littoralis caterpillars, our results also suggest that the ABA-inducible effects on DIMBOA and chlorogenic acid are not solely responsible for root herbivore-induced resistance against S. littoralis.Key words: induced resistance, Spodoptera littoralis, Zea mays, Diabrotica virgifera, DIMBOA, chlorogenic acid, absisic acid, priming 相似文献
82.
Background
Multi-locus sequence typing (MLST) is a method of typing that facilitates the discrimination of microbial isolates by comparing the sequences of housekeeping gene fragments. The mlstdbNet software enables the implementation of distributed web-accessible MLST databases that can be linked widely over the Internet. 相似文献83.
A novel approach to investigate biofilm accumulation and bacterial transport in porous matrices 总被引:1,自引:0,他引:1
Knowledge of bacterial transport through, and biofilm growth in, porous media is vitally important in numerous natural and engineered environments. Despite this, porous media systems are generally oversimplified and the local complexity of cell transport, biofilm formation and the effect of biofilm accumulation on flow patterns is lost. In this study, cells of the sulphate-reducing bacterium, Desulfovibrio sp. EX265, accumulated primarily on the leading faces of obstructions and developed into biofilm, which grew to narrow and block pore throats (at a rate of 12 micro m h(-1) in one instance). This pore blocking corresponded to a decrease in permeability from 9.9 to 4.9 Darcy. Biofilm processes were observed in detail and quantitative data were used to describe the rate of biofilm accumulation temporally and spatially. Accumulation in the inlet zone of the micromodel was 10% higher than in the outlet zone and a mean biofilm height of 28.4 micro m was measured in a micromodel with an average pore height of 34.9 microm. Backflow (flow reversal) of fluid was implemented on micromodels blocked with biofilm growth. Although biofilm surface area cover did immediately decrease (approximately 5%), the biofilm quickly re-established and permeability was not significantly affected (9.4 Darcy). These results demonstrate that the glass micromodel used here is an effective tool for in situ analysis and quantification of bacteria in porous media. 相似文献
84.
The ‘Werribee farrowing pen' (WFP) was developed as a loose housing alternative to the farrowing crate. The WFP occupies about twice the space of a crate and comprises two compartments, a ‘nest' and a ‘non-nest' area. In this experiment, we investigated the effects of reducing total pen space by modifying the dimensions of the ‘nest'. The hypothesis was that modifying ‘nest' size and width would not negatively affect piglet survival. A reduction in total floor space in the WFP may increase attractiveness for adoption of the system by pig producers. The experiment had a 2×2 factorial design with nine replicates and a total of 72 primiparous sows (Large White×Landrace) and their litters. All subjects were included to day 4 of lactation, but production data to weaning (day 23) was restricted to 36 litters. We examined the effects of ‘nest' size (large: L vs. small: S) and width (wide: W vs. narrow: N) on sow and piglet behaviours and piglet survival. The W, as compared to N treatment sows, had longer mean bouts of standing in the ‘nest' during 16–8 h pre-farrowing (3.7 vs. 2.0 min, P<0.01), suggesting that pre-farrowing (‘nesting') behaviour may have been adversely affected by narrow nest width. On the first 2 days of lactation, sow suckling grunts occurred more in the W than N treatment (14.1 and 8.0% of observations, P<0.01). However, this was due to an approximately 50% lower incidence in the SN treatment, as compared to the other treatments combined (5.9 and 12.7%). Piglets spent more (P<0.01) time at the udder in L vs. S (41 and 30%) and W vs. N nests (40 and 31%) and performed more (P<0.05) sucking behaviour (i.e., drinking milk from a teat) in L vs. S nests (2.5 and 1.2%). These differences were due to SN treatment litters sucking less than other treatments combined (0.9 vs. 2.2%). Of the 680 piglets born (n=72 litters), 3.8% were stillborn and 6.8% died between birth and day 4 of lactation. From day 5 to weaning (n=36 litters), 3.5% of piglets died, all due to Escherichia coli infection. While there were no effects of treatment on piglet survival, liveborn piglets were less likely (P<0.05) to die from E. coli in the L vs. S treatments (9/24 vs. 23/33 piglets). In conclusion, our results provide evidence that the size and width of the farrowing ‘nest' in a loose farrowing system may effect sow and piglet behaviours that may be relevant to piglet survival. 相似文献
85.
In the current model for Glc3Man9GlcNAc2-P-P-Dol assembly, Man5GlcNAc2-
P-P-Dol, Man-P-Dol, and Glc-P-Dol are synthesized on the cytoplasmic face
of the ER and diffuse transversely to the lumenal leaflet where the
synthesis of the lipid-bound precursor oligosaccharide is completed. To
establish the topological sites of Glc-P-Dol synthesis and the
lipid-mediated glucosyltransfer reactions involved in
Glc3Man9GlcNAc2-P-P-Dol synthesis in ER vesicles from pig brain, the
trypsin-sensitivity of Glc-P-Dol synthase activity and the Glc-P-
Dol:Glc0-2Man9GlcNAc2-P-P-Dol glucosyltransferases (GlcTases) was examined
in sealed microsomal vesicles. Since ER vesicles from brain do not contain
glucose 6-phosphate (Glc 6-P) phosphatase activity, the latency of the
lumenally oriented, processing glucosidase I/II activities was used to
assess the intactness of the vesicle preparations. Comparative enzymatic
studies with sealed ER vesicles from brain and kidney, a tissue that
contains Glc 6-P phosphatase, demonstrate the reliability of using the
processing glucosidase activities as latency markers for topological
studies with microsomal vesicles from non-gluconeogenic tissues lacking Glc
6-P phosphatase. The results obtained from the trypsin-sensitivity assays
with sealed microsomal vesicles from brain are consistent with a
topological model in which Glc-P-Dol is synthesized on the cytoplasmic face
of the ER, and subsequently utilized by the three Glc-P-Dol-mediated
GlcTases after "flip-flopping" to the lumenal monolayer.
相似文献
86.
Isolated populations of drosophila pseudoobscura, separated from North
American populations by about 2,400 km, were found in Colombia in 1960. We
compared for sequences of the small ribosomal RNA (srRNA) gene on the
mitochondria between North American and Colombian D. pseudoobscura in order
to clarify the age of the Colombian isolates. The North American
populations were not genetically different from each other but were
genetically different from the Colombian populations. The Mexican strains
represent the area from which the Colombian founders might have come. The
estimated net nucleotide divergence between Mexican and Colombian D.
pseudoobscura indicates that the Colombian population is not an ancient
lineage. Phylogenies using both distance and parsimony methodologies
reinforced this conclusion. The Colombian samples group together with both
methods but, according to the bootstrap analysis, not significantly. It
appears that the populations have not been separated long enough for their
DNA sequences to show much divergence.
相似文献
87.
88.
89.
AS Glen D Anderson CJ Veltman PM Garvey M Nichols 《New Zealand journal of zoology.》2016,43(2):127-137
A major challenge in controlling overabundant wildlife is monitoring their populations, particularly as they decline to very low density. Camera traps and wildlife detector dogs are increasingly being used for this purpose. We compared the cost-effectiveness of these two approaches for detecting feral cats (Felis catus) on two pastoral properties in Hawke's Bay, North Island, New Zealand. One property was subject to intensive pest removal, while the other had no recent history of pest control. Camera traps and wildlife detector dogs detected cats at similar rates at both sites. The operating costs of each method were also comparable. We identify a number of advantages and disadvantages of each technique, and suggest priorities for further research. 相似文献
90.
TD Smith KP Bhatnagar CJ Bonar KL Shimp MP Mooney MI Siegel 《American journal of physical anthropology》2003,122(3):301-301