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101.
Kateřina Kuželová Dana Grebeňová Michaela Pluskalová Daniel Kavan Petr Halada Zbyněk Hrkal 《Journal of cellular biochemistry》2009,106(4):673-681
The proteins of 14‐3‐3 family are substantially involved in the regulation of many biological processes including the apoptosis. We studied the changes in the expression of five 14‐3‐3 isoforms (β, γ, ε, τ, and ζ) during the apoptosis of JURL‐MK1 and K562 cells. The expression level of all these proteins markedly decreased in relation with the apoptosis progression and all isoforms underwent truncation, which probably corresponds to the removal of several C‐terminal amino acids. The observed 14‐3‐3 modifications were partially blocked by caspase‐3 inhibition. In addition to caspases, a non‐caspase protease is likely to contribute to 14‐3‐3's cleavage in an isoform‐specific manner. While 14‐3‐3 γ seems to be cleaved mainly by caspase‐3, the alternative mechanism is essentially involved in the case of 14‐3‐3 τ, and a combined effect was observed for the isoforms ε, β, and ζ. We suggest that the processing of 14‐3‐3 proteins could form an integral part of the programmed cell death or at least of some apoptotic pathways. J. Cell. Biochem. 106: 673–681, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
102.
Incubation behaviour of the Meadow Pipit (Anthus pratensis) in an alpine ecosystem of Central Europe
Incubation behaviour of the Meadow Pipit (Anthus pratensis) was investigated in mountainous conditions in Central Europe (the Krkonoše Mountains of the Czech Republic), in relation
to the time of day and weather. Twenty-four-hour recordings of incubation behaviour were made with a time-lapse video recorder
and mini-camera. The influences of year, nest, time of day, temperature, precipitation and previous bouts on session and recess
duration were then analysed. The incubation behaviour of Meadow Pipits in general did not differ from the behaviour of other
small female-only incubating passerines. Despite relatively cold climatic conditions in the study area, the mean length of
sessions and recesses (19.69 and 5.53 min), as well as nest-attentiveness (77.19%), agreed with values which are most often
found in other species. However, the Meadow Pipit incubation in the study area was, in terms of nest-attentiveness, more intensive
than in other surveyed populations of this species. Incubation behaviour was strongly influenced by the time of day—incubating
females increased nest-attentiveness during the morning and evening hours. After the time of day was filtered out, the influence
of temperature was found only on sessions (not recesses). Sessions were the longest when the air temperature was approximately
12–16°C and shortened when the temperature was lower or higher. Precipitation forced female Meadow Pipits to take longer sessions
and shorter recesses, which corresponds to their general tendency to give priority to the needs of the clutch ahead of their
own temporary feeding needs. 相似文献
103.
Petr Kovář Miroslav Pospíšil Petr Malý Zdeněk Klika Pavla Čapková Petra Horáková Marta Valášková 《Journal of molecular modeling》2009,15(11):1391-1396
The surface area of various types of montmorillonites (MMT) with different values of layer charge plays a very important role
in surface arrangement of methylene blue cations (MB). Photoluminescence measurements can be strongly or partially influenced
by this surface arrangement of cations. For these reasons and on the basis of our previous results, molecular simulations
were performed for various types of montmorillonites covered with methylene blue cations. Adsorption of methylene blue cations
on Na-Wyoming MMT surface is different from Ca-Cheto MMT. In the case of Wyoming with a lower layer charge, MB cations lie
parallel to the silicate layer for all investigated samples. On the other hand, Cheto surface is covered with a higher amount
of MB cations. The results obtained from molecular modeling indicate that MB lies parallel to low loading case and become
tilted with respect to layer for a higher loading. Moreover, a higher amount of MB cations covering the silicate layer are
much less energy-stable. A higher loading of MB cations leads to aggregates but at low loading MB cations degrade to monomers. 相似文献
104.
Klára J. Petrželková Hideo Hasegawa Chris C. Appleton Michael A. Huffman Colleen E. Archer Liza R. Moscovice Mwanahamissi Issa Mapua Jatinder Singh Taranjit Kaur 《American journal of primatology》2010,72(4):307-316
The release of any species into a novel environment can evoke transmission of parasites that do not normally parasitize the host as well as potentially introducing new parasites into the environment. Species introductions potentially incur such risks, yet little is currently known about the parasite fauna of introduced primate species over the long term. We describe the results of long‐term monitoring of the intestinal parasite fauna of an unprovisioned, reproducing population of chimpanzees introduced 40 years earlier (1966–1969) onto Rubondo Island in Lake Victoria, Tanzania, a non‐native habitat for chimpanzees. Two parasitological surveys (March 1997–October 1998 and October 2002–December 2005) identified Entamoeba spp. including E. coli, Iodamoeba buetschlii, Troglodytella abrassarti, Chilomastix mesnili, Trichuris sp., Anatrichosoma sp., Strongyloides spp., Strongylida fam. gen. sp., Enterobius anthropopitheci, Subulura sp., Ascarididae gen. sp., and Protospirura muricola. The parasite fauna of the Rubondo chimpanzees is similar to wild chimpanzees living in their natural habitats, but Rubondo chimpanzees have a lower prevalence of strongylids (9%, 3.8%) and a higher prevalence of E. anthropopitheci (8.6%, 17.9%) than reported elsewhere. Species prevalence was similar between our two surveys, with the exception of Strongyloides spp. being higher in the first survey. None of these species are considered to pose a serious health risk to chimpanzees, but continued monitoring of the population and surveys of the parasitic fauna of the two coinhabitant primate species and other animals, natural reservoir hosts of some of the same parasites, is important to better understand the dynamics of host–parasite ecology and potential long‐term implications for chimpanzees introduced into a new habitat. Am. J. Primatol. 72:307–316, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
105.
We measured the proliferation of roots into experimental nutrient patches in a grassland community, distinguishing roots of graminoids and forbs. Biomass, length, and specific length were estimated for roots of each of the two functional groups, collected from patches differing in nutrient concentration, and established at four different times during a season. The ratio of graminoid and forb roots was compared with the graminoid-forb ratio in the above-ground biomass. Plant roots proliferated more intensively into patches with higher nutrient concentration, but the roots of the two functional groups had a similar ability to target richer patches. Relative proportion of graminoids was higher below-ground than above-ground and changed during the season, being lowest after mowing. Specific root length was higher for graminoid species, but did not respond to nutrient concentration in patches for either functional group. This is the first study to provide comparative information about root morphological response for graminoids and forbs, measured in a real, semi-natural plant community. The study shows no significant overall difference in the ability of these two functional types to place roots into nutrient-rich patches, but indicates other important differences among the two functional groups. 相似文献
106.
107.
Petr Sklenář 《Plant Ecology》2006,184(2):337-350
Altitudinal variation of the zonal superpáramo vegetation was studied between 4300 and 4630 m to test a possible occurrence
of a fine altitudinal zonation within the superpáramo belt. A rectangular grid of 1 m2 sample plots was established; 25 replicate plots separated by a 3 m space were located along a 100 m long transect parallel
to the contours, and there were 17 such transects separated by 20 m of altitude. Species were scored using a 7-grade cover
scale and basic environmental data were gathered for each sample. Major changes occur over a short altitudinal range, at around
4400 m, which corresponds to a transition between the lower and upper superpáramo. Species richness sharply declines but species
turnover (per altitude) increases along the altitudinal gradient. The correlation between richness and bare ground or rock
cover is negative, but the correlation to rocks becomes positive above 4500 m. Species from lower altitudes tend to have narrower
altitudinal range, although a large number of species appear to be indifferent to altitude. Direct ordination analyses indicate
that high-altitude species show stronger correlation to environmental variables, especially rock, than species from lower
altitudes. TWINSPAN cluster analysis delimited 15 groups of samples. There is a change in the clustering pattern along the
altitudinal gradient from a horizontal (i.e., within altitude) to vertical (i.e., across altitude) arrangement of the cluster
groups, although this pattern is partly obscured at the highest altitudes due to a large number of empty samples. MANOVA tests
for samples from adjacent altitudinal levels indicate two distinct altitudinal breaks at lower altitudes, corresponding to
the Loricaria-belt in lower superpáramo and the transition between lower and upper superpáramo, while no indication of a zonation was found
in upper superpáramo. 相似文献
108.
Petr Šmarda 《Folia Geobotanica》2006,41(4):417-432
DNA ploidy level estimates are presented for 11 species and two natural hybrids ofFestuca sampled from 39 locations in Romania. Altogether 48 living samples (22 of them also as one-year-old herbarium specimens) and additional 65 one-year-old herbarium specimens were analyzed using flow cytometry with DAPI staining. The following DNA ploidy levels were assessed:F. callieri (4x),F. ovina (2x),F. pallens (2x),F. polesica (2x),F. pseudodalmatica (2x, 4x, 5x),F. pseudovaginata (2x),F. pseudovina (2x),F. pseudovina ×F. rupicola (4x),F. rupicola (6x),F. vaginata (2x),F. vaginata ×F. valesiaca (2x),F. valesiaca (2x) andF. xanthina (2x).Festuca pseudovaginata is reported for the flora of Romania for the first time. Measurements of one-year-old herbarium specimens produced significantly smaller sample/standard ratios (P<0.001) and higher coefficients of variance (P < 0.001) when compared with fresh plant samples. Several species exhibited marked intraspecific nuclear DNA content variability, documented by non-overlapping double-peaks or bimodal peaks in simultaneous measurements. A maximum difference of about 9.2% in relative DNA contents was observed inF. pallens, 5.5% inF. polesica, 4.2% inF. vaginata, and 3.8% inF. rupicola. DiploidF. xanhina (Festuca sect.Eskia) had 1.39–1.58 times higher monoploid relative DNA content in relation to the species of sectionFestuca. 相似文献
109.
The biogeography of naturalization in alien plants 总被引:9,自引:0,他引:9
Aim This paper reviews the main geographical determinants of naturalization in plants.
Location Global.
Methods Comparative studies of large data sets of alien floras are the main source of information on global patterns of naturalization.
Results Temperate mainland regions are more invaded than tropical mainland regions but there seems to be no difference in invasibility of temperate and tropical islands. Islands are more invaded than the mainland. The number of naturalized species in temperate regions decreases with latitude and their geographical ranges increase with latitude. The number of naturalized species on islands increases with temperature. Naturalized species contribute to floristic homogenization, but the phenomenon is scale-dependent.
Main conclusions Some robust patterns are evident from currently available data, but further research is needed on several aspects to advance our understanding of the biogeography of naturalization of alien plants. For example, measures of propagule pressure are needed to determine the invasibility of communities/ecosystems/regions. The patterns discussed in this paper are derived largely from numbers and proportions of naturalized species, and little is known about the proportion of introduced species that become naturalized. Further insights on naturalization rates, i.e. the proportion of aliens that successfully naturalize within regions, and on geographical and other determinants of its variation would provide us with better understanding of the invasion process. Comparative studies, and resulting generalizations, are almost exclusively based on numbers of species, but alien species differ in their impact on native biodiversity and ecosystem processes. 相似文献
Location Global.
Methods Comparative studies of large data sets of alien floras are the main source of information on global patterns of naturalization.
Results Temperate mainland regions are more invaded than tropical mainland regions but there seems to be no difference in invasibility of temperate and tropical islands. Islands are more invaded than the mainland. The number of naturalized species in temperate regions decreases with latitude and their geographical ranges increase with latitude. The number of naturalized species on islands increases with temperature. Naturalized species contribute to floristic homogenization, but the phenomenon is scale-dependent.
Main conclusions Some robust patterns are evident from currently available data, but further research is needed on several aspects to advance our understanding of the biogeography of naturalization of alien plants. For example, measures of propagule pressure are needed to determine the invasibility of communities/ecosystems/regions. The patterns discussed in this paper are derived largely from numbers and proportions of naturalized species, and little is known about the proportion of introduced species that become naturalized. Further insights on naturalization rates, i.e. the proportion of aliens that successfully naturalize within regions, and on geographical and other determinants of its variation would provide us with better understanding of the invasion process. Comparative studies, and resulting generalizations, are almost exclusively based on numbers of species, but alien species differ in their impact on native biodiversity and ecosystem processes. 相似文献
110.
Ping Wang Paul P.C.A. Menheere Arne Astrup Malene R. Andersen Marleen A. van Baak Thomas M. Larsen Susan Jebb Anthony Kafatos Andreas F.H. Pfeiffer J. Alfredo Martinez Teodora Handjieva‐Darlenska Petr Hlavaty Nathalie Viguerie Dominique Langin Wim H.M. Saris Edwin C.M. Mariman Diogenes consortium 《Obesity (Silver Spring, Md.)》2013,21(10):1997-2006