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971.
A García-Fernández A Lázaro-Nogal A Traveset F Valladares 《American journal of botany》2012,99(8):e307-e309
? Premise of the study: The main aim of this study was to isolate and characterize microsatellite loci in Cneorum tricoccon (Cneoraceae), a Mediterranean shrub relict of the early Tertiary, which inhabits western Mediterranean islands and coasts. Microsatellites will be useful for investigating biogeography and landscape genetics across the species distribution range, including current or past gene flow. ? Methods and Results: Seventeen microsatellite loci were characterized, of which 10 were polymorphic and amplified for a total of 56 alleles in three populations of C. tricoccon. The markers revealed average coefficients of expected heterozygosity (H(e) = 0.425), observed heterozygosity (H(o) = 0.282), and inbreeding coefficient value per population (F(IS) = 0.408). ? Conclusions: These microsatellite primers will potentially be useful in the study of population and landscape genetics, conservation status of isolated populations, island-continental distribution, current or historical movements between populations, and in the investigation of the consequences of dispersal mechanisms of these plants. 相似文献
972.
Yan S Bleuler-Martinez S Plaza DF Künzler M Aebi M Joachim A Razzazi-Fazeli E Jantsch V Geyer R Wilson IB Paschinger K 《The Journal of biological chemistry》2012,287(34):28276-28290
The modification of α1,6-linked fucose residues attached to the proximal (reducing-terminal) core N-acetylglucosamine residue of N-glycans by β1,4-linked galactose ("GalFuc" epitope) is a feature of a number of invertebrate species including the model nematode Caenorhabditis elegans. A pre-requisite for both core α1,6-fucosylation and β1,4-galactosylation is the presence of a nonreducing terminal N-acetylglucosamine; however, this residue is normally absent from the final glycan structure in invertebrates due to the action of specific hexosaminidases. Previously, we have identified two hexosaminidases (HEX-2 and HEX-3) in C. elegans, which process N-glycans. In the present study, we have prepared a hex-2;hex-3 double mutant, which possesses a radically altered N-glycomic profile. Whereas in the double mutant core α1,3-fucosylation of the proximal N-acetylglucosamine was abolished, the degree of galactosylation of core α1,6-fucose increased, and a novel Galα1,2Fucα1,3 moiety attached to the distal core N-acetylglucosamine residue was detected. Both galactosylated fucose moieties were also found in two parasitic nematodes, Ascaris suum and Oesophagostomum dentatum. As core modifications of N-glycans are known targets for fungal nematotoxic lectins, the sensitivity of the C. elegans double hexosaminidase mutant was assessed. Although this mutant displayed hypersensitivity to the GalFuc-binding lectin CGL2 and the N-acetylglucosamine-binding lectin XCL, the mutant was resistant to CCL2, which binds core α1,3-fucose. Thus, the use of C. elegans mutants aids the identification of novel N-glycan modifications and the definition of in vivo specificities of nematotoxic lectins with potential as anthelmintic agents. 相似文献
973.
Luciana F. Alves Marco A. Assis Juliano van Melis Ana L. S. Barros Simone A. Vieira Fernando R. Martins Luiz A. Martinelli Carlos A. Joly 《Ecological Research》2012,27(2):323-332
Lianas play a key role in forest structure, species diversity, as well as functional aspects of tropical forests. Although
the study of lianas in the tropics has increased dramatically in recent years, basic information on liana communities for
the Brazilian Atlantic Forest is still scarce. To understand general patterns of liana abundance and biomass along an elevational
gradient (0–1,100 m asl) of coastal Atlantic Forest, we carried out a standard census for lianas ≥1 cm in five 1-ha plots
distributed across different forest sites. On average, we found a twofold variation in liana abundance and biomass between
lowland and other forest types. Large lianas (≥10 cm) accounted for 26–35% of total liana biomass at lower elevations, but
they were not recorded in montane forests. Although the abundance of lianas displayed strong spatial structure at short distances,
the present local forest structure played a minor role structuring liana communities at the scale of 0.01 ha. Compared to
similar moist and wet Neotropical forests, lianas are slightly less abundant in the Atlantic Forest, but the total biomass
is similar. Our study highlights two important points: (1) despite some studies have shown the importance of small-scale canopy
disturbance and support availability, the spatial scale of the relationships between lianas and forest structure can vary
greatly among tropical forests; (2) our results add to the evidence that past canopy disturbance levels and minimum temperature
variation exert influence on the structure of liana communities in tropical moist forests, particularly along short and steep
elevational gradients. 相似文献
974.
Jose Alexandre F. Diniz‐Filho Luis Mauricio Bini Thiago Fernando Rangel Ignacio Morales‐Castilla Miguel Á. Olalla‐Tárraga Miguel Á. Rodríguez Bradford A. Hawkins 《Ecography》2012,35(3):239-249
Among the statistical methods available to control for phylogenetic autocorrelation in ecological data, those based on eigenfunction analysis of the phylogenetic distance matrix among the species are becoming increasingly important tools. Here, we evaluate a range of criteria to select eigenvectors extracted from a phylogenetic distance matrix (using phylogenetic eigenvector regression, PVR) that can be used to measure the level of phylogenetic signal in ecological data and to study correlated evolution. We used a principal coordinate analysis to represent the phylogenetic relationships among 209 species of Carnivora by a series of eigenvectors, which were then used to model log‐transformed body size. We first conducted a series of PVRs in which we increased the number of eigenvectors from 1 to 70, following the sequence of their associated eigenvalues. Second, we also investigated three non‐sequential approaches based on the selection of 1) eigenvectors significantly correlated with body size, 2) eigenvectors selected by a standard stepwise algorithm, and 3) the combination of eigenvectors that minimizes the residual phylogenetic autocorrelation. We mapped the mean specific component of body size to evaluate how these selection criteria affect the interpretation of non‐phylogenetic signal in Bergmann's rule. For comparison, the same patterns were analyzed using autoregressive model (ARM) and phylogenetic generalized least‐squares (PGLS). Despite the robustness of PVR to the specific approaches used to select eigenvectors, using a relatively small number of eigenvectors may be insufficient to control phylogenetic autocorrelation, leading to flawed conclusions about patterns and processes. The method that minimizes residual autocorrelation seems to be the best choice according to different criteria. Thus, our analyses show that, when the best criterion is used to control phylogenetic structure, PVR can be a valuable tool for testing hypotheses related to heritability at the species level, phylogenetic niche conservatism and correlated evolution between ecological traits. 相似文献
975.
Jiska Jebbink Astrid Wolters Febilla Fernando Gijs Afink Joris van der Post Carrie Ris-Stalpers 《生物化学与生物物理学报:疾病的分子基础》2012,1822(12):1960-1969
Preeclampsia is characterised by new onset hypertension and proteinuria and is a major obstetrical problem for both mother and foetus. Haemolysis elevated liver enzymes and low platelets (HELLP) syndrome is an obstetrical emergency and most cases occur in the presence of preeclampsia. Preeclampsia and HELLP are complicated syndromes with a wide variety in severity of clinical symptoms and gestational age at onset. The pathophysiology depends not only on periconceptional conditions and the foetal and placental genotype, but also on the capability of the maternal system to deal with pregnancy. Genetically, preeclampsia is a complex disorder and despite numerous efforts no clear mode of inheritance has been established. A minor fraction of HELLP cases is caused by foetal homozygous LCHAD deficiency, but for most cases the genetic background has not been elucidated yet. At least 178 genes have been described in relation to preeclampsia or HELLP syndrome. Confined placental mosaicism (CPM) is documented to cause early onset preeclampsia in some cases; the overall contribution of CPM to the occurrence of preeclampsia has not been adequately investigated yet. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure. 相似文献
976.
Luiz Fernando Mendes Luiz A. S. Vale Aline Paternostro Martins Nair Sumie Yokoya Eliane Marinho-Soriano Pio Colepicolo 《Journal of applied phycology》2012,24(6):1419-1426
In the present study, the daily relative growth rates (DRGR, in percent per day) of the red macroalga Gracilaria domingensis in synthetic seawater was investigated for the combined influence of five factors, i.e., light (L), temperature (T), nitrate (N), phosphate (P), and molybdate (M), using a statistical design method. The ranges of the experimental cultivation conditions were T, 18–26°C; L, 74–162?μmol photons m?2?s?1; N, 40–80?μmol?L?1; P, 8–16?μmol?L?1; and M, 1–5?nmol?L?1. The optimal conditions, which resulted in a maximum growth rate of ≥6.4% d?1 from 7 to 10?days of cultivation, were determined by analysis of variance (ANOVA) multivariate factorial analysis (with a 25 full factorial design) to be L, 74?μmol photons m?2?s?1; T, 26°C; N, 80?μmol?L?1; P, 8?μmol?L?1; and M, 1?nmol?L?1. In additional, these growth rate values are close to the growth rate values in natural medium (von Stosch medium), i.e., 6.5–7.0% d?1. The results analyzed by the ANOVA indicate that the factors N and T are highly significant linear terms, X L, (α?=?0.05). On the other hand, the only significant quadratic term (X Q) was that for L. Statistically significant interactions between two different factors were found between T vs. L and N vs. T. Finally, a two-way (linear/quadratic interaction) model provided a quite reasonable correlation between the experimental and predicted DRGR values (R adjusted 2 ?=?0.9540). 相似文献
977.
Antimicrobial lipopeptaibol trichogin GA IV: role of the three Aib residues on conformation and bioactivity 总被引:1,自引:0,他引:1
The lipopeptaibol trichogin GA IV is a natural, non-ribosomally synthesized, antimicrobial peptide remarkably resistant to the action of hydrolytic enzymes. This feature may be connected to the multiple presence in its sequence of the non-coded residue α-aminoisobutyric acid (Aib), which is known to be responsible for the adoption of particularly stable helical structures already at the level of short peptides. To investigate the role of Aib residues on the 3D-structure and bioactivity of trichogin GA IV, we synthesized and fully characterized four analogs where one or two Aib residues are replaced by L-Leu. Our extensive conformational studies (including an X-ray diffraction analysis) and biological assays performed on these analogs showed that the Aib to L-Leu replacements do not affect the resistance to proteolysis, but modulate the bioactivity of trichogin GA IV in a 3D-structure related manner. 相似文献
978.
Sunetra Sase Deeba Khan Fernando Sialana Harald H?ger Nina Russo-Schlaff Gert Lubec 《Amino acids》2012,43(6):2285-2292
Modafinil has been shown to modify behavioural and cognitive functions and to effect several brain receptors. Effects, however, were not observed at the receptor protein complex level and it was therefore the aim of the study to train mice in the multiple T-Maze (MTM) as a paradigm for spatial memory and to determine paralleling brain receptor complex levels. Sixty C57BL/6J mice were used in the study and divided into four groups (trained drug injected; trained vehicle injected; yoked drug injected; yoked vehicle injected). Animals obtained training for 4?days and were killed 6?h following the last training session on day 4. Hippocampi were dissected from the brain, membrane fractions were prepared by ultracentrifugation and were run on blue-native gels and immunoblotted with antibodies against major brain receptors. Modafinil treatment led to decreased latency and increased average speed, but not to changes in pathlength and number of correct decisions in the MTM. Drug effects were modifying receptor complexes of GluR1, GluR2, D2 and NR1. Training effects on receptor complex levels were observed for GluR3, D1 and nicotinic acetylcholine receptor alpha 7 (Nic7). GluR1 levels were correlating with GluR2 and D1 levels were correlating with D2 and NR1. Involvement of the glutamatergic, NMDA, dopaminergic and nicotinergic system in modafinil and memory training were herein described for the first time. A brain receptor complex pattern was revealed showing the concerted action following modafinil treatment. 相似文献
979.
The availability of most edible ectomycorrhizal mushrooms depends on their natural fructification. Sporocarp formation of
these fungi is linked to habitat characteristics and climate conditions, but these data alone do not explain all the trends
of fungal fruiting and dynamics. It could be hypothesized that the amount of soil mycelia could also be related to the production
of carpophores. Soil samples (five cylinders of 250 cm3 per plot) were taken monthly, from September to November, in five fenced permanent plots (5 × 5 m) in Pinar Grande (Soria,
Spain), a Pinus sylvestris stand situated in the north of the Sistema Ibérico mountain range. Plots were chosen to establish a gradient of Boletus edulis productivity from 0 to 38.5 kg/ha year, according to the mean fresh weight of sporocarps collected during the last 10 years.
B. edulis ectomycorrhizal root tips were identified in each soil sample according to its morphology and counted. DNA extractions were
performed with the PowerSoilTM DNA Isolation Kit and quantification of extraradical soil mycelium by real-time polymerase chain reaction using specific
primers and a TaqMan? probe. The concentration of soil mycelium of B. edulis (mg mycelium/g soil) did not differ significantly between plots (p = 0.1397), and sampling time (p = 0.7643) within the fructification period. The number of mycorrhizal short roots per soil volume showed significant differences
between the plots (p = 0.0050) and the three sampling times (p < 0.0001). No significant correlation between the number of mycorrhizas and the productivity of the plot (kg of B. edulis/ha year) was detected (p = 0.615). A statistically significant positive correlation (p = 0.0481) was detected between the concentration of mycelia of B. edulis in the soil samples and the presence of short roots mycorrhizal with B. edulis in these samples. The productivity of the plots, in terms of sporocarps produced during the last 10 years, was not correlated
either with the concentration of soil mycelium or with the presence or abundance of ectomycorrhizas. 相似文献
980.