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41.
Datasets from the mitochondrial gene regions NADH dehydrogenase subunit I (ND1) and cytochrome c oxidase subunit I (COI) of the 20 species in the New Zealand wolf spider (Lycosidae) genus Anoteropsis were generated. Sequence data were phylogenetically analysed using parsimony and maximum likelihood analyses. The phylogenies generated from the ND1 and COI sequence data and a previously generated morphological dataset were significantly congruent (p<0.001). Sequence data were combined with morphological data and phylogenetically analysed using parsimony. The ND1 region sequenced included part of tRNALeu(CUN), which appears to have an unstable amino-acyl arm and no TψC arm in lycosids. Analyses supported the existence of five species groups within Anoteropsis and the monophyly of species represented by multiple samples. A radiation of Anoteropsis species within the last five million years is inferred from the ND1 and COI likelihood phylograms, habitat and geological data, which also indicates that Anoteropsis arrived in New Zealand some time after it separated from Gondwana. 相似文献
42.
Animal aggregation is a general phenomenon in ecological systems. Aggregations are generally considered as an evolutionary advantageous state in which members derive the benefits of mate choice and protection against natural enemies, balanced by the costs of limiting resources and intraspecific competition. Many insects use chemical information to find conspecifics and to form aggregations. In this study, we describe a spatio-temporal simulation model designed to explore and quantify the effects of the strength of chemical attraction, on the colonization ability of a fruit fly (Drosophila melanogaster) population. We found that the use of infochemicals is crucial for colonizing an area. Fruit flies subject to an Allee effect that are unable to respond to chemical information could not successfully colonize the area and went extinct within four generations. This was mainly caused by very high mortality due to the Allee effect. Even when the Allee effect did not play a role, the random dispersing population had more difficulties in colonizing the area and is doomed to extinction in the long run. When fruit flies had the ability to respond to chemical information, they successfully colonized the orchard. This happened faster, for stronger attraction to chemical information. In addition, more fruit flies were able to find the resources and the settlement on the resources was much higher. This resulted in a reduced mortality due to the Allee effect for fruit flies able to respond to chemical information. Odor-mediated aggregation thus enhances the colonization ability of D. melanogaster. Even a weak attraction to chemical information paved the way to successfully colonize the orchard. 相似文献
43.
Federico Fogolari Haritha Haridas Alessandra Corazza Paolo Viglino Davide Corà Michele Caselle Gennaro Esposito Luigi E Xodo 《BMC structural biology》2009,9(1):64-20
Background
Independent surveys of human gene promoter regions have demonstrated an overrepresentation of G3X n1G3X n2G3X n3G3 motifs which are known to be capable of forming intrastrand quadruple helix structures. In spite of the widely recognized importance of G-quadruplex structures in gene regulation and growing interest around this unusual DNA structure, there are at present only few such structures available in the Nucleic Acid Database. In the present work we generate by molecular modeling feasible G-quadruplex structures which may be useful for interpretation of experimental data. 相似文献44.
Daniela Camargos Costa Ana Paula Madureira Lara Cotta Amaral Bruno Ant?nio Marinho Sanchez Luciano Teixeira Gomes Cor Jésus Fernandes Fontes Jean Ezequiel Limongi Cristiana Ferreira Alves de Brito Luzia Helena Carvalho 《Memórias do Instituto Oswaldo Cruz》2014,109(1):21-28
The polymerase chain reaction (PCR)-based methods for the diagnosis of malaria
infection are expected to accurately identify submicroscopic parasite carriers.
Although a significant number of PCR protocols have been described, few studies have
addressed the performance of PCR amplification in cases of field samples with
submicroscopic malaria infection. Here, the reproducibility of two well-established
PCR protocols (nested-PCR and real-time PCR for the Plasmodium 18
small subunit rRNA gene) were evaluated in a panel of 34 blood field samples from
individuals that are potential reservoirs of malaria infection, but were negative for
malaria by optical microscopy. Regardless of the PCR protocol, a large variation
between the PCR replicates was observed, leading to alternating positive and negative
results in 38% (13 out of 34) of the samples. These findings were quite different
from those obtained from the microscopy-positive patients or the unexposed
individuals; the diagnosis of these individuals could be confirmed based on the high
reproducibility and specificity of the PCR-based protocols. The limitation of PCR
amplification was restricted to the field samples with very low levels of
parasitaemia because titrations of the DNA templates were able to detect < 3
parasites/µL in the blood. In conclusion, conventional PCR protocols require careful
interpretation in cases of submicroscopic malaria infection, as inconsistent and
false-negative results can occur. 相似文献
45.
Dos Santos RA Batista J Rosa SI Torquato HF Bassi CL Ribeiro TA De Sousa PT Bessera AM Fontes CJ Da Silva LE Piuvezam MR 《Parasitology》2011,138(10):1224-1233
Leishmaniasis is one of the neglected diseases. High cost, systemic toxicity, and diminished efficacy due to development of resistance by the parasites has a negative impact on the current treatment options. Thus, the search for a new, effective and safer anti-leishmanial drug becomes of paramount importance. Compounds derived from natural products may be a better and cheaper source in this regard. This study evaluated the in vitro anti-leishmanial activity of Spiranthera odoratíssima (Rutaceae) fractions and isolated compounds, using promastigote and amastigote forms of different Leishmania species. J774 A.1 macrophage was used as the parasite host cell for the in vitro assays. Evaluations of cytoxicity, nitric oxide (NO), interleukin-10 and in silico analysis were carried out. In vitro experiments showed that the fruit hexanic fraction (Fhf) and its alkaloid skimmianine (Skm) have a significant (P<0·001) effect against L. braziliensis. This anti-L. braziliensis activity of Fhf and Skm was due to increased production of NO and attenuation of IL-10 production in the macrophages at concentrations ranging from 1·6 to 40·0 μg/ml. The in silico assay demonstrated significant interaction between Skm and amino acid residues of NOS2. Skm is thus a promising drug candidate for L. braziliensis due to its potent immunomodulatory activity. 相似文献
46.
Stefania Casagrande Cor Dijkstra James Tagliavini Vivian C. Goerlich Ton G. G. Groothuis 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(1):1-13
Recent studies have demonstrated that carotenoid-based traits are under the control of testosterone (T) by up-regulation of
carotenoid carriers (lipoproteins) and/or tissue-specific uptake of carotenoids. T can be converted to dihydrotestosterone
(DHT) and estradiol (E2), and variation in conversion rate may partly explain some contradictory findings in the literature.
Moreover, most studies on the effect of T on sexual signals have focused on the male sex only, while in many species females
show the same signal, albeit to a lesser extent. We studied the effects of T, DHT, and E2 treatment in male and female diamond
doves Geopelia cuneata in which both sexes have an enlarged red eye ring, which is more pronounced in males. We first showed that this periorbital
ring contains very high concentration of carotenoids, of which most are lutein esters. Both T and DHT were effective in enhancing
hue, UV-chroma and size in both sexes, while E2 was ineffective. However, E2 dramatically increased the concentration of circulating
lipoproteins. We conclude that in both sexes both color and size of the secondary sexual trait are androgen dependent. The
action of androgens is independent of lipoproteins regulation. Potential mechanisms and their consequences for trade-off are
discussed. 相似文献
47.
van Winden WA van Dam JC Ras C Kleijn RJ Vinke JL van Gulik WM Heijnen JJ 《FEMS yeast research》2005,5(6-7):559-568
Metabolic-flux analyses in microorganisms are increasingly based on (13)C-labeling data. In this paper a new approach for the measurement of (13)C-label distributions is presented: rapid sampling and quenching of microorganisms from a cultivation, followed by extraction and detection by liquid chromatography-mass spectrometry of free intracellular metabolites. This approach allows the direct assessment of mass isotopomer distributions of primary metabolites. The method is applied to the glycolytic and pentose phosphate pathways of Saccharomyces cerevisiae strain CEN.PK113-7D grown in an aerobic, glucose-limited chemostat culture. Detailed investigations of the measured mass isotopomer distributions demonstrate the accuracy and information-richness of the obtained data. The mass fractions are fitted with a cumomer model to yield the metabolic fluxes. It is estimated that 24% of the consumed glucose is catabolized via the pentose phosphate pathway. Furthermore, it is found that turnover of storage carbohydrates occurs. Inclusion of this turnover in the model leads to a large confidence interval of the estimated split ratio. 相似文献
48.
49.
Jagoba Malumbres-Olarte Barbara I. P. Barratt Cor J. Vink Adrian M. Paterson Robert H. Cruickshank Colin M. Ferguson Diane M. Barton 《Biological invasions》2014,16(11):2311-2322
As post-disturbance community response depends on the characteristics of the ecosystem and the species composition, so does the invasion of exotic species rely on their suitability to the new environment. Here, we test two hypotheses: exotic spider species dominate the community after burning; and two traits are prevalent for their colonisation ability: ballooning and body size, the latter being correlated with their dispersal ability. We established spring burn, summer burn and unburned experimental plots in a New Zealand tussock grassland area and collected annual samples 3 and 4 years before and after the burning, respectively. Exotic spider abundance increased in the two burn treatments, driven by an increase in Linyphiidae. Indicator analysis showed that exotic and native species characterised burned and unburned plots, respectively. Generalised linear mixed-effects models indicated that ballooning had a positive effect on the post-burning establishment (density) of spiders in summer burn plots but not in spring plots. Body size had a positive effect on colonisation and establishment. The ability to balloon may partly explain the dominance of exotic Linyphiidae species. Larger spiders are better at moving into and colonising burned sites probably because of their ability to travel longer distances over land. Native species showed a low resilience to burning, and although confirmation requires longer-term data, our findings suggest that frequent fires could cause long lasting damage to the native spider fauna of tussock grasslands, and we propose limiting the use of fire to essential situations. 相似文献
50.
Arjen B Blom Peter L van Lent Hanneke van Vuuren Astrid E Holthuysen Cor Jacobs Leo B van de Putte Jan G van de Winkel Wim B van den Berg 《Arthritis research & therapy》2000,2(6):489-15
We investigated the role of Fcγ receptors (FcγRs) on synovial macrophages in immune-complex-mediated arthritis (ICA). ICA
elicited in knee joints of C57BL/6 mice caused a short-lasting, florid inflammation and reversible loss of proteoglycans (PGs),
moderate chondrocyte death, and minor erosion of the cartilage. In contrast, when ICA was induced in knee joints of Fc receptor
(FcR) γ-chain-/- C57BL/6 mice, which lack functional FcγRI and RIII, inflammation and cartilage destruction were prevented. When ICA was elicited
in DBA/1 mice, a very severe, chronic inflammation was observed, and significantly more chondrocyte death and cartilage erosion
than in arthritic C57BL/6 mice. The synovial lining and peritoneal macrophages of na?ve DBA/1 mice expressed a significantly
higher level of FcγRs than was seen in C57BL/6 mice. Moreover, elevated and prolonged expression of IL-1 was found after stimulation
of these cells with immune complexes. Zymosan or streptococcal cell walls caused comparable inflammation and only mild cartilage
destruction in all strains. We conclude that FcγR expression on synovial macrophages may be related to the severity of synovial
inflammation and cartilage destruction during ICA. 相似文献