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1.
Seedlings of two common Mediterranean trees, Pinus halepensis L. and Quercus ilex L., were grown alone and together with seedlings
of the same or of the other species in the same pot during one year to test the effects of intra- and inter-specific interference
on terpene emission. Light, nutrients and water were amply supplied. There were higher emission rates in P. halepensis than
in Q. ilex. The emission increased when the neighbour was a pine and decreased when the neighbour was a holm oak. Volatile
organic compound and terpene emission rates followed inverse trends to foliar biomass or growth, which decreased when the
neighbour was a pine.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
We aimed to assess the potential effects of fumigation by methyl salicylate (MeSA) on plant monoterpene production and emissions.
We evaluated monoterpene production and emissions both by chromatographic and proton transfer reaction mass spectrometry at
the whole plant-and leaf-scales, in MeSa-fumigated (ca. 60 mm3 m−3 in air) and control (without MeSa fumigation) holm oak (Quercus ilex L.) plants exposed to temperatures ranging from 25 to 50 °C. The MeSa-fumigated plants showed ca. 3–4-fold greater leaf monoterpene concentrations and emission rates than the control plants between the temperatures of 25
to 45 °C. 相似文献
3.
4.
The seasonal pattern of terpene content and emission by seven Mediterranean woody species was studied under field conditions. Emission rates were normalized at 30°C and 1000 μmol·m·s PFD (photosynthetic photon flux density). Bupleurum fruticosum, Pinus halepensis, and Cistus albidus stored large amounts of terpenes (0.01-1.77% [dry matter]) with maximum values in autumn and minimum values in spring. They emitted large amounts of terpenes (2-40 μg·g DM·h), but with no clear seasonal trend except for Cistus albidus, which had maximum values in spring and minimum values in autumn. The nonstoring species Arbutus unedo, Erica arborea, Quercus coccifera and Quercus ilex also emitted large amounts of terpenes (0-40 μg·g DM·h) and also tended to present maximum emission rates in spring, although this trend was significant only for A. unedo. At the seasonal scale, emission rates did not follow changes in photosynthetic rates; instead, they mostly followed changes in temperature. From autumn to spring, the least volatile monoterpenes such as limonene were emitted at highest rates, whereas the most volatile monoterpenes such as α-pinene and β-pinene were the most emitted in summer. The monoterpene emission rates represented a greater percentage of the photosynthetic carbon fixation in summer (from 0.51% in Arbutus unedo to 5.64% in Quercus coccifera) than in the rest of the seasons. All these seasonality trends must be considered when inventorying and modeling annual emission rates in Mediterranean ecosystems. 相似文献
5.
Distribution of genetic diversity in Pinus pinaster Ait. as revealed by chloroplast microsatellites 总被引:4,自引:0,他引:4
G. G. Vendramin M. Anzidei A. Madaghiele G. Bucci 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):456-463
Using nine chloroplast simple sequence.repeats (cpSSRs) markers, we evaluated haplotypic variation within and among natural
populations of Maritime pine (Pinus pinaster Ait.) in order to shed light on the history of this species. Seven out of the nine cpSSRs analysed were polymorphic, giving
a total of 24 different variants. The 24 variants combined in 34 different haplotypes. The populations which generally showed
the lowest level of haplotypic diversity are those located in Portugal. The Landes (France) and Pantelleria (Italy) populations
represent the two main reservoirs of haplotypic diversity. The proportion of genetic differentiation among populations, estimated
using Rst, which is a measure based upon a strict stepwise mutation model, was 0.235. The high level of differentiation was also confirmed
by the AMOVA analysis (ΦST=0.254, P<0.001). Four main groups of populations were identified on the basis of Principal Component Analysis, with the differences
being statistically significant (ΦCT=0.299, P<0.001). Based on our results the presence of refugia located in the South of Portugal, previously proposed for this species,
may be excluded, and a different possible recolonization process of Maritime pine in the post-glacial period has been proposed.
Populations from North Africa and France might have represented a starting point of the recolonization process of Portugal
and of the Italian part of the natural range, respectively. This hypothesis seems to be confirmed by the analysis of the distribution
of the pairwise differences among individuals within populations: Landes and Pantelleria populations showed a bimodal distribution,
as would be expected for ancient gene pools.
Received: 5 November 1997 / Accepted: 5 January 1998 相似文献
6.
To understand the unusual polar body formation in the androgenetic clam, Corbicula leana, whole-mount eggs stained with monoclonal antibodies against α-tubulin, γ-tubulin, and 4’-6’-diamidino-2-phenylindole were
examined. The meiotic spindle was located at the peripheral region of the egg at metaphase I, and its axis was parallel to
the egg surface. After segregation of chromosomes at anaphase I, cytoplasmic bulges formed at both meiotic spindle pole sites.
Centrosomes were located at the apical portion of the each bulge. From the apical portion of the bulge a bundle of astral
microtubules radiated toward the bulge base in late anaphase resembling a half spindle. Maternal chromosomes and both centrosomes
were all distributed in two ”first polar bodies” and were eventually discarded. After the polar body formation only one male
pronucleus existed in the egg cytoplasm. The present study showed that the anaphase microtubules originating from a single
aster can induce the polar body formation without overlapping of microtubules from the opposing aster.
Received: 29 September 1999 / Accepted: 24 November 1999 相似文献
7.
We studied the aggregation state of Photosystem II in stacked and unstacked thylakoid membranes from spinach after a quick
and mild solubilization with the non-ionic detergent n-dodecyl-α,D-maltoside, followed by analysis by diode-array-assisted gel filtration chromatography and electron microscopy.
The results suggest that Photosystem II (PS II) isolates either as a paired, appressed membrane fragment or as a dimeric PS
II-LHC II supercomplex upon mild solubilization of stacked thylakoid membranes or PS II grana membranes, but predominantly
as a core monomer upon mild solubilization of unstacked thylakoid membranes. Analysis of paired grana membrane fragments reveals
that the number of PS II dimers is strongly reduced in single membranes at the margins of the grana membrane fragments. We
suggest that unstacking of thylakoid membranes results in a spontaneous disintegration of the PS II-LHC II supercomplexes
into separated PS II core monomers and peripheral light-harvesting complexes.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
9.
Ecological Diversity and Biodiversity as Concepts for Conservation Planning: Comments on Ricotta 总被引:3,自引:0,他引:3
Sarkar S 《Acta biotheoretica》2006,54(2):133-140
Ricotta argues against the existence of a unique measure of biodiversity by pointing out that no known measure of α-diversity
satisfies all the adequacy conditions that have traditionally been set for it. While that technical claim is correct, it is
not relevant in the context of defining biodiversity which is most usefully measured by β-diversity. The concept of complementarity provides a closely related family of measures of biodiversity which can be used
for systematic conservation planning. Moreover, these measures cannot be replaced by summary statistics but must rely on inventories
of biodiversity surrogates at candidate sites for conservation. 相似文献
10.
Stem-growth response of Pinus sylvestris and Picea abies to nitrogen fertilization as related to needle nitrogen concentration 总被引:2,自引:0,他引:2
U. Sikström Hans-Örjan Nohrstedt Folke Pettersson Staffan Jacobson 《Trees - Structure and Function》1998,12(4):208-214
Responses of stem-volume growth to N application were evaluated in relation to foliar N concentrations. Data from N-fertilization
experiments in 28 Pinus sylvestris stands and 21 Picea abies stands were used. Relative stem-growth responses were negatively related to concentrations of N in current-year needles of
unfertilized trees. There appeared to be a threshold value of 15–16 mg (g DM)–1 N in current-year needles, above which N-application is unlikely to stimulate growth. However, relations were non-significant
between N concentrations in current-year needles and the absolute stem-growth response [dm3 ha–1 (5 years)–1]. The indicated threshold values are discussed in relation to other variables reflecting the N richness of the environment.-->
Received: 20 December 1996 / Accepted: 30 September 1997 相似文献
11.
Respiration Rate and Chemical Composition of Karwinskia Roots as Affected by Temperature 总被引:3,自引:0,他引:3
Two-year-old plants of Karwinskia humboldtiana Zucc. and Karwinskia parvifolia Rose grown from the seeds in greenhouse were transferred to the growth cabinet and cultivated for two months under different temperature regimes (35/20 °C - the summer temperature regime, SR, and 20/5 °C - the winter temperature regime, WR). These temperatures were similar to the temperature conditions in the natural areas of the species studied (Nuevo León, Mexico). The root respiration rate was higher in the plants cultivated under SR than in those under WR. Roots of K. parvifolia res faster in both temperature regimes than roots of K. humboldtiana. Starch content in roots was higher in the plan cultivated under SR, however, concentrations of the other investigated organic and inorganic compounds were higher in the plants cultivated under WR. In K. humboldtiana roots, higher concentration of reducing sugars, carbon and hydrogen were found than in K. parvifolia. 相似文献
12.
Zélia Silva Nuno Borges Lígia O. Martins Robin Wait Milton S. da Costa H. Santos 《Extremophiles : life under extreme conditions》1999,3(2):163-172
In this study we propose revised structures for the two major compatible solutes of Rhodothermus marinus. We have also examined the accumulation of compatible solutes by the type strains of the slightly halophilic and thermophilic
species Rhodothermus marinus and Rhodothermus obamensis at several growth temperatures and salinities. The major solutes of R. marinus were identified as α-mannosylglycerate (α-MG) and α-mannosylglyceramide (α-MGA), whereas R. obamensis accumulated only α-mannosylglycerate. The total osmolyte content was higher during the early exponential phase and decreased
abruptly as growth continued into the stationary phase. At low growth temperatures, R. marinus responded to water stress by accumulation of α-mannosylglycerate and its amide, in addition to low levels of trehalose, glutamate,
and glucose. At the highest growth temperature, α-mannosylglycerate was the major compatible solute and α-mannosylglyceramide
was not detected. When both compounds were present, an increase in the salinity of the growth medium favored the accumulation
of α-mannosylglyceramide over α-mannosylglycerate. The absence of α-mannosylglyceramide in R. obamensis at all growth temperatures and salinities constituted the most pronounced difference in the profiles of compatible solute
accumulation by the two strains. Trehalose was also a prominent solute in this organism. Both organisms accumulated higher
levels of α-mannosylglycerate as the temperature was raised. The importance of the two compounds in the mechanisms of thermoadaptation
and osmoadaptation is discussed.
Received: February 10, 1998 / Accepted: January 11, 1999 相似文献
13.
The aim of this study was to investigate the role of plants colonised by two ectomycorrhizal fungi, Paxillus involutus and Suillus variegatus, in mobilising potassium (K) from biotite and microcline, two minerals common in acid to medium-acid bedrock. This was carried
out in a 33-week pot study with seedlings of Pinus sylvestris growing in symbiosis with the fungi, where no K was added or where K was added in the form of biotite or microcline. The
mineral additions were similar to those found in natural soils. All seedlings, including non-mycorrhizal, were able to access
the K in biotite, leading to stimulated growth and K uptake relative to controls. Microcline addition induced growth depression
in all seedlings except those colonised by P. involutus, which were stimulated. The soil solution from S. variegatus-colonised seedlings grown with biotite had higher concentrations of citric and oxalic acid. Citric acid concentration was
positively correlated to the fungal biomass (ergosterol) in the soil, as well as to the foliar K in S. variegatus-colonised seedlings. Seedlings growing without K addition had low K concentrations in the shoot. Magnesium (Mg) concentrations
were enhanced in seedlings with severe K shortage, indicating that Mg can substitute for K, while calcium concentrations did
not vary significantly.
Accepted: 18 January 1999 相似文献
14.
Marra M Agostinelli E Tempera G Lombardi A Meo G Budillon A Abbruzzese A Giuberti G Caraglia M 《Amino acids》2007,33(2):273-281
Summary. A correlation between regulation of cell proliferation and polyamine metabolism is described. The latter can enter protein
synthesis through the modification of eukaryotic initiation factor 5A (eIF5A) and the formation of the peculiar amino acid
hypusine. Specific inhibitors of hypusine formation induce apoptosis that can be potentiated by the combination with cytokines
such as interferonα (IFNα) that itself decreases hypusine synthesis. We have also demonstrated that the concomitant treatment
of cancer cells with IFNα and the protein synthesis inhibitor fusion protein TGFα/Pseudomonas Aeruginosa toxin synergize in inducing cancer cell growth inhibition. Another way used by polyamines to induce apoptosis is the generation
of intracellular oxidative stress through the interaction with bovine serum amine oxidase (BSAO). This enzyme used simultaneously
to spermine induces apoptosis, necrosis, inhibition of cell proliferation and inhibition of DNA and protein synthesis in several
cell types. The enzymatic oxidation products of polyamine, H2O2 and aldehyde(s) cause these effects. We have recently found that the cytotoxicity of anti-cancer agents, either etoposide
or docetaxel, in cancer cells is potentiated in the presence of BSAO/Spermine. In conclusion, polyamine metabolites could
be useful in the design of new therapeutic strategies. 相似文献
15.
Jessica D. Martin Yusai Ito Vanessa V. Homann Margo G. Haygood Alison Butler 《Journal of biological inorganic chemistry》2006,11(5):633-641
The coastal α-proteobacterium Ochrobactrum sp. SP18 produces a suite of three citrate-derived, cell-associated amphiphilic siderophores, ochrobactins A–C. The ochrobactins are composed of a citric acid backbone amide-linked to two lysine residues. Each ε-amine of lysine is hydroxylated and acylated forming two hydroxamic acid moieties. One of the acylated appendages of each ochrobactin is (E)-2-decenoic acid. The other acylated appendages for ochrobactins A–C are (E)-2-octenoic acid, octanoic acid and (E)-2-decenoic acid, respectively. The ferric ochrobactin complexes are photoreactive in UV light, producing an oxidized ligand with loss of 46 mass units that can still coordinate Fe(III). The relative partitioning of the apo-ochrobactins, Fe(III) ochrobactins and Fe(III) photoproducts into 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles is presented. The ochrobactins are the first example of aerobactin-based siderophores with two fatty acid appendages produced in a suite with varying acyl appendage lengths.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
16.
Peptaibiomics: an advanced, rapid and selective analysis of peptaibiotics/peptaibols by SPE/LC-ES-MS
Summary. “Proteomics” and “peptidomics” are used as technical terms to define the analysis and study of all proteins and peptides expressed
in an organism or tissue. In analogy we propose the name peptaibiomics for the analysis of a group of fungal peptide antibiotics (peptaibiotics) containing the characteristic amino acid Aib (α-aminoisobutyric
acid). In analogy to the peptidome the complete expression of peptaibiotics by fungal multienzyme complexes should be named
the peptaibiome.
Peptaibiotics are defined as peptides containing Aib and exerting a variety of bioactivities. They comprise the sub-groups
of N-acetylated peptaibols, characterized also by a C-terminal amide-linked 2-amino alcohol, and lipopeptaibols having in place of an acetyl group a lipophilic fatty acid acyl
group. Furthermore, lipoaminopeptides are also known with long-chain fatty acid on the N-termini, a lipoamino acid in position three and a strongly basic secondary or tertiary amine form a subgroup of mixed forms
which could not be integrated in one of these three previously mentioned groups.
Here we present a specific and rapid screening method on the peptaibiome applicable directly onto filamentous fungi cultured
in a single Petri dish. The method comprises solid-phase extraction (SPE) of peptaibiotics followed by on-line reversed-phase
HPLC coupled to an ion trap electrospray tandem mass spectrometer (ES-MS). The presence of these peptides is indicated by
characteristic mass differences of Δm = 85.1 Da representing Aib-residues which can be observed in the b-series of acylium fragment ions resulting from ES-MS. Partial sequences can be deduced from the data and compared with structures
compiled in electronic peptaibol data bases. The judgement is possible whether or not structures are novel, already known
or related to known structures. Suitability of the method is demonstrated with the analysis of strains of Trichoderma and its teleomorph Hypocrea. New sequences of peptaibiotics are presented and those being related to established 10- to 18-residue peptaibols trichovirin,
trichogin and trichotoxin, which have been described in the literature. 相似文献
17.
M.A. Sobrado 《Photosynthetica》1999,36(4):547-555
In leaves of the mangrove species Avicennia germinans (L.) L. grown in salinities from 0 to 40 ‰, fluorescence, gas exchange, and δ13C analyses were done. Predawn values of Fv/Fm were about 0.75 in all the treatments suggesting that leaves did not suffer chronic photoinhibition. Conversely, midday Fv/Fm values decreased to about 0.55-0.60 which indicated strong down-regulation of photosynthesis in all treatments. Maximum photosynthetic
rate (P
max) was 14.58 ± 0.22 μmol m-2 s-1 at 0 ‰ it decreased by 21 and 37 % in plants at salinities of 10 and 40 ‰, respectively. Stomatal conductance (g
s) was profoundly responsive in comparison to P
max which resulted in a high water use efficiency. This was further confirmed by δ13C values, which increased with salinity. From day 3, after salt was removed from the soil solution, P
max and g
s increased up to 13 and 30 %, respectively. However, the values were still considerably lower than those measured in plants
grown without salt addition.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
Mühling J Nickolaus KA Halabi M Fuchs M Krüll M Engel J Wolff M Matejec R Langefeld TW Welters ID Menges T Dehne MG Sablotzki A Hempelmann G 《Amino acids》2005,29(3):289-300
Summary. The objective of this study was to determine the dose as well as duration of exposure-dependent effects of L-alanyl-L-glutamine,
arginine or taurine on polymorphonuclear neutrophil (PMN) free α-keto acid profiles and, in a parallel study, on PMN immune
functions. Exogenous L-alanyl-L-glutamine significantly increased PMN α-ketoglutarate, pyruvate PMN superoxide anion (O2−) generation, hydrogen peroxide (H2O2) formation and released myeloperoxidase (MPO) activity. Arginine also led to significant increases in α-ketoglutarate, pyruvate,
MPO release and H2O2 generation. Formation of O2− on the other hand was decreased by arginine. Incubation with taurine resulted in lower intracellular pyruvate and α-ketobutyrate
levels, decreased O2− and H2O2 formation and a concomitant significantly increased MPO activity. We therefore believe that considerable changes in PMN free-α-keto-acid
profiles, induced for example by L-alanyl-L-glutamine, arginine or taurine, may be one of the determinants in cell nutrition
that considerably modulates the immunological competence of PMN. 相似文献
19.
Yamasaki M Nishida E Nou S Tachibana H Yamada K 《In vitro cellular & developmental biology. Animal》2005,41(7):239-244
Summary This study was performed to evaluate the isomer-specific cytotoxic effects of conjugated linoleic acid (CLA) on rat hepatoma
dRLh-84 cells in vitro. A 10trans,12cis (10t,12c)-CLA showed a strong cytotoxic effect on dRLh-84 cells in culture, whereas no such effect was observed with 9cis,11trans (9c,11t)-CLA or linoleic acid. The optimum concentration for induction of cytotoxity by 10t,12c-CLA was 5 to 10 μM, but the effect was alleviated at higher concentrations. Coincubation with oleic or palmitoleic acid and 10t,12c-CLA cancelled the cytotoxic effect, but other major saturated or polyunsaturated fatty acids and eraidic acid did not interfere
with 10t,12c-CLA-induced cytotoxity. The cytotoxic effect was also alleviated by α-tocopherol (α-toc) and α-tocotrienol but not by any
other antioxidant regent examined. Significant cytotoxity of 10t,12c-CLA was detected after only a 15-min incubation, and the most noticeable effect was seen after 3 h. After incubation with
10t,12c-CLA at 10 μM, an additional 90 μM, an additional 90 μM of 10t,12c-CLA or 100 μM of α-toc was also able to alleviate the cytotoxity. When cells were treated with 10 μM 10t,12c-CLA for more than 48 h, treatment with additional CLA or α-toc could not prevent cell death. 相似文献
20.
Stephan Niland Anja Cremer Katja Herzhoff Betty V. Nusgens Charles M. Lapière Thomas Krieg Beate Eckes 《In vitro cellular & developmental biology. Animal》2001,37(9):606-612
In order to characterize a fibroblast cell line representing normal human skin fibroblasts in three-dimensional cultures, we compared the fibroblast line MSU-1.1, derived from human foreskin and immortalized by v-myc, to primary human dermal fibroblasts (NDF). Our results demonstrate that in contrast to NDF, all MSU-1.1 fibroblasts die within 3-4 d when cultured within three-dimensional contractile collagen matrices. Also, in contrast to NDF. MSU-1.1 cells die markedly in anchored collagen gels as well. Death is due to apoptosis and is attenuated by addition of antibodies against collagen-recognizing receptors alpha1beta1 and alpha2beta1. Apoptosis of NDF in collagen lattices was repressed by an inhibitor of caspase-1, which was ineffective on apoptosis of MSU-1.1. Further, apoptosis by MSU-1.l fibroblasts was also observed in anchored, i.e., restrained collagen lattices, an environment that supports proliferation of NDF. 相似文献