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991.
Luís M. Rosalino Maria J. Santos Iris Pereira Margarida Santos-Reis 《European Journal of Wildlife Research》2009,55(3):293-299
Sexual dimorphism in carnivores can result from, or induce, variations in diet and foraging behaviour between individuals
of different sexes. Sex-driven behavioural changes in feeding habits may also result in a reduction in intraspecific competition
for resources, avoiding dietary overlap by concentrating on different prey sizes/types. We therefore evaluated the variation
in feeding habits of both males and females of an invasive and range expanding southern European carnivore, the Egyptian mongoose
(Herpestes ichneumon), through gut content analysis of road or predator-control killed animals. The analysis of 59 gut samples, collected in Portugal,
revealed that northwestern populations of mongooses prey mostly upon mammals [especially lagomorphs, percentage of biomass
(PB) = 44%], reptiles (PB = 28%) and arthropods (PB = 2% but percentage of occurrence = 35%). However, females seem to focus
mainly on reptiles (PB = 51%) and mammals (PB = 38%), whilst males consume mostly mammals (PB = 75%). The results suggest
that this variation maybe a result of sexual dimorphism (since some variation is documented in a few Egyptian mongoose’s skull
measures, namely condylobasal length and canine diameter), with males shifting their diets to prey from which they can obtain
more energy. Females seem to be focused on predating lighter animals, probably females or juveniles, a fact that has important
game management implications. 相似文献
992.
The genus Penicillium is one of the largest and widely distributed fungal genera described to date. As a result, its taxonomic classification and
species discrimination within this genus has become complicated. In this study, 52 isolates that belonged to the Penicillum genus and other related genera were characterized using two DNA-based methods: (i) analysis of the nucleotide sequences of
internal transcribed spacers in ribosomal DNA and (ii) analysis of DNA fingerprints that were generated by polymerase chain
reactions with specific primers for enterobacterial repetitive intergenic consensus (ERIC) and repetitive extragenic palindromic
(REP) sequences, and BOX elements. Using both methods, Penicillium species were discriminated from other fungal genera. Furthermore, Penicillium species that include strains which are used as biocontrol agents, such as P. glabrum, P. purpurogenum, and P. oxalicum, could be distinguished from other Penicillium species using these techniques. Based on our findings, we propose that a polyphasic approach that includes analysis of the
nucleotide sequences of ribosomal DNA and detecting the presence of highly conserved, repeated nucleotide sequences can be
used to determine the genetic relationships between different Penicillium species. Furthermore, we propose that our results can be used as a start point to develop a strategy to monitor the environmental
presence of particular strains of Penicillium species when they are used as biocontrol agents. 相似文献
993.
994.
Hui Xie Jian-ye Chen Rong-cai Yuan Yu-xiong Zhong Hai-ling Feng Shi-juan Xu Jian-guo Li Wang-jin Lu 《Plant Growth Regulation》2009,58(3):225-233
In this work, five expansin cDNAs (DlExp1–5) from ‘Shijia’ longan fruit were isolated and characterized. Moreover, the expression profiles of five expansin genes and the effect of naphthalene acetic acid (NAA) and thidiazuron (TDZ) on their expressions were investigated. The results
showed that five expansins exhibited different expression patterns during fruit growth and development. DlExp1 was constitutively expressed in the pericarp while the levels of DlExp1 mRNA in the aril were very high at early stage of fruit development, and decreased gradually from 28 to 77 days after anthesis
(DAA). DlExp2 and DlExp4 were related to the growth of pericarp, whereas the expression of DlExp2 and DlExp5 in the aril decreased from 28 to 77 DAA. In addition, NAA and TDZ applied at the stage of rapid pericarp (21 DAA) or aril
growth (56 DAA) increased the accumulations of DlExp1 and DlExp2 mRNA in the pericarp and aril, while NAA and TDZ had no or little effect on the accumulations of DlExp3, DlExp4 and DlExp5. DlExp1 and DlExp2 also accumulated highly in rapidly growing tissues, such as young stems and leaves. These findings indicated that Exp genes played a different role in longan fruit growth and showed different response to plant growth substances. 相似文献
995.
Cory T. Williams Sara J. Iverson C. Loren Buck 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(6):711-720
Fatty acid (FA) signature analysis is a powerful tool to investigate foraging ecology and food web dynamics in marine ecosystems.
However, use of FA signatures to qualitatively or quantitatively infer diets is potentially complicated by effects of nutritional
state on lipid metabolism. Estimation of diets using the quantitative fatty acid signature analysis (QFASA) model requires
the use of calibration coefficients to account for predator metabolism of individual FAs. We conducted a captive feeding experiment
to determine the effects of a 50% reduction in food intake on growth rate and adipose tissue FA signatures of tufted puffin
(Fratercula cirrhata) nestlings, a species that routinely experiences food restriction during growth. FA signatures of chicks fed low- and high-calorie
diets both exhibited a change in composition in response to the dietary shift with the direction of change in the composition
of individual FAs matching the direction of change in the dietary FAs. Despite a growth rate in the restricted nestlings that
was 38% of those in the well-fed group, rates of FA turnover were not different between high and low-calorie treatments, and
turnover was close to, but not entirely complete, after 27 days on both high-calorie and restricted diets. FA signatures of
tufted puffin nestlings were significantly affected by caloric restriction, but these effects were much less pronounced than
those of dietary turnover, and calibration coefficients of puffins fed low and high-calorie diets were highly correlated.
Our results demonstrate that changes in physiological state can affect FA metabolism, but future research is required to better
understand whether the size of these effects is sufficient to substantially alter diet estimation using the QFASA model. 相似文献
996.
Bojan Kozlev?ar Ivan Leban Saša Petri?ek Jan Reedijk 《Inorganica chimica acta》2004,357(14):4220-4230
A series of compounds of formula [{Cu2(OOCCmH2m + 1)4(urea)}2] (m=5-11) have been characterized. X-ray structure analysis for the hexanoate compound reveals a new type of tetranuclear dicopper(II) tetracarboxylate, where the central coordination sphere in [{Cu2(OOCC5H11)4(urea)}2] is composed of two dinuclear dicopper tetracarboxylates, connected via two inter-dinuclear Cu-O coordination bonds at a distance 2.222(2) Å through the apical positions of two dimers. Urea molecules (Cu-O 2.114(2) Å) occupy both outside apical positions of the resulting tetranuclear units. A strong antiferromagnetic behaviour has been shown for [{Cu2(OOCC5H11)4(urea)}2] (−2J=261.4(4) cm−1), and compared with related isolated dinuclear and polymeric hexanoate compounds [Cu2(OOCC5H11)4(urea)2], [Cu2(OOCC5H11)4]n, respectively. Only small differences in the magnetic susceptibility have been found, while EPR spectroscopy showed significantly different results for all three hexanoate compounds, also with the dicopper tetracarboxylate central core and square-pyramidal CuO4O chromophores. A solid-to-solid phase transition for [{Cu2(OOCC5H11)4(urea)}2] was observed by magnetic measurement and analysed for the whole series [{Cu2(OOCCmH2m + 1)4(urea)}2] by TG, DTA, and variable temperature XRD studies. 相似文献
997.
Iankov ID Petrov DP Mladenov IV Haralambieva IH Kalev OK Balabanova MS Mitov IG 《Microbes and infection / Institut Pasteur》2004,6(10):901-910
Protective properties of immunoglobulin A (IgA) monoclonal antibodies (MAbs) directed against O and H antigens of Salmonella enterica serotype Enteritidis (S. enteritidis) were evaluated in a model of generalized infection after intranasal (i.n.) inoculation of BALB/c mice. Passive i.n. instillation of antibodies 1 h before i.n. challenge did not prevent infection, and mice developed rapid inflammatory response in the lower respiratory tract. The passive systemic immunization was partially protective and a single intravenous (i.v.) injection of both O and H antigen specific IgA antibodies prolonged survival period of the infected animals. Permanent secretion of O:9 specific IgA MAb 177E6 into the respiratory tract in a "backpack" tumor model protected 50% of animals infected i.n. with a high dose of virulent S. enteritidis strain. Thus, secretory IgA (S-IgA) directed against O:9 antigen alone can prevent bacterial invasion in the respiratory epithelium. 相似文献
998.
With the ultimate aim of developing bioremediation technology that use the optimum bacterial community for each pollutant, we performed polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis and identified communities of culturable bacteria in HgCl(2)- and trichloroethylene (TCE)-contaminated soil microcosms. PCR-DGGE band patterns were similar at 0 and 1 ppm HgCl(2), but changes in specific bands occurred at 10 ppm HgCl(2). Band patterns appearing at 10 and 100 ppm TCE were very different from those at 0 ppm. Phylogenetic analysis showed four bacterial groups in the HgCl(2)-contaminatied cultures: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Most high-density bands, decreased-density bands, and common bands were classified into the phyla Proteobacteria, Actinobacteria, and Firmicutes, respectively; the effects of HgCl(2) on culturable bacteria appeared to differ among phyla. Duganella violaceinigra [98.4% similarity to DNA Data Bank of Japan (DDBJ) strain], Lysobacter koreensis (98.2%), and Bacillus panaciterrae (98.6%) were identified as bacteria specific to HgCl(2)-contaminated soils. Bacteria specific to TCE-contaminated soils were distributed into three phyla (Firmicutes, Proteobacteria, and Actinobacteria), but there was no clear relationship between phylum and TCE effects on culturable bacteria. Paenibacillus kobensis (97.3%), Paenibacillus curdlanolyticus (96.3%), Paenibacillus wynnii (99.8%), and Sphingomonas herbicidovorans (99.4%) were identified as bacteria specific to TCE-contaminated soils. These bacteria may be involved in pollutant degradation. 相似文献
999.
We conducted a 6-year field manipulation drought experiment in an evergreen Quercus ilex forest where we simulated the drought predicted by GCM and ecophysiological models for the coming decades (an average of
15% soil moisture reduction). We thereby tested the hypothesis that enhanced drought will change Ca, Fe, Mg, Mo and S availability,
concentrations and accumulation patterns in Mediterranean ecosystems. The strongest effects of drought occurred in the soil.
Drought increased the total soil concentrations of S, the soil extract concentrations of Fe, Mg and S, the Mg saturation in
the soil exchangeable complex and tended to increase the percentage base saturation of the soil exchangeable complex. These
increased soil concentrations were related to a decrease of plant uptake capacity and not to an increase of soil enzyme activity,
which in fact decreased under drier conditions. Drought increased leaf Mg concentrations in the three dominant species although
only significantly in Quercus ilex and Arbutus unedo (20 and 14%, respectively). In contrast, drought tended to decrease Ca in Phillyrea latifolia (18%) and Ca and Fe concentrations in the wood of all three species. Drought increased Ca and Fe concentrations in the roots
of Quercus ilex (26 and 127%). There was a slight general trend to decrease total biomass accumulation of nutrients that depend on water
flux such as Mg, Fe and S. This effect was related to a decrease of soil moisture that reduced soil flow, and to a decrease
in photosynthetic capacity, sap flow, transpiration and growth, and therefore plant uptake capacity under drought observed
in Quercus ilex and Arbutus unedo. On the contrary, drought increased Mo accumulation in aboveground biomass in Phillyrea latifolia and reduced Mo accumulation in Arbutus unedo by reducing growth and wood Mo concentrations (51%). Phillyrea latifolia showed a great capacity to adapt to drier conditions, with no decrease in growth, an increase of Mo uptake capacity and a
decrease in leaf Ca concentration, which was related to a decrease in transpiration under drought. The results indicate asymmetrical
changes in species capacity to accumulate these elements, which are likely to produce changes in inter-specific competitive
relations among dominant plant species and in their nutritional quality as food sources. The results also indicate that drought
tended to decrease nutrient content in aboveground biomass, mainly through the decrease in growth and transpiration of the
most sensitive species and caused an increase in the availability of these nutrients in soil. Thus, drought decreased the
ecosystem’s capacity to retain Mg, Fe and S, facilitating their loss in torrential rainfalls. 相似文献
1000.
Wu G Wu Y Xiao L Li X Lu C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(4):491-499
The fatty acid elongase 1 (FAE1) gene is a key gene in the erucic acid biosynthesis in rapeseed. The complete coding sequences of the FAE1 gene were isolated separately from eight high and zero erucic acid rapeseed cultivars (Brassica napus L.). A four base pair deletion between T1366 and G1369 in the FAE1 gene was found in a number of the cultivars, which leads to a frameshift mutation and a premature stop of the translation
after the 466th amino acid residue. This deletion was predominantly found in the C-genome and rarely in the A-genome of B. napus. Expression of the gene isoforms with the four base pair deletion in a yeast system generated truncated proteins with no
enzymatic activity and could not produce very long chain fatty acids as the control with an intact FAE1 gene did in yeast cells. In the developing rape seeds the FAE1 gene isoforms with the four base pair deletion were transcribed normally but failed to translate proteins to form a functional
complex. The four base pair deletion proved to be a mutation responsible for the low erucic acid trait in rapeseed and independent
from the point mutation reported by Han et al. (Plant Mol Biol 46:229–239, 2001).
Gang Wu, Yuhua Wu contribute equally to this article. 相似文献