The invasion of Austria by the alien vascular plant Ambrosia artemisiifolia (Asteraceae) is analysed in detail, based on a survey of available records. In total, 697 records were collated. The first record for Austria is a herbarium specimen collected in 1883. Up to the end of the 1940s, records were rare and only of casual populations resulting from long-distance dispersal. Since the 1950s, the number of records has increased exponentially, and more than one third of all records (242) were collected in the last 5-year period (2001–2005) included in the survey. The first naturalized population was recorded in 1952, nearly 70 years after the first record of a casual population. Recently, the number of naturalized populations increased considerably faster than that of casual populations. Several pathways (contaminated crops and bird seed, agricultural machines, transport of soil) have contributed to the high levels of propagule pressure and this successful invasion. Ambrosia artemisiifolia has undergone a niche expansion during the invasion process. Up to 1950, most records were from sites along railway routes, whereas in the period 1950–1974 itwas mostly ruderal habitats, not associated with traffic infrastructure, which were colonized. Since the 1970s, records from roadsides have increased strongly and now dominate. Fields were colonized first in the 1970s and since then have gained in importance. The distribution of naturalized populations was related to environmental and climatic variables by means of a generalized linear model. Their distribution in Austria is closely related to temperature. Landscape variables, describing aspects of habitat availability (topography, land use, major street density) also significantly explain the current distribution of A. artemisiifolia. Suitable habitats currently occur mainly in the eastern and southeastern lowlands. We conclude that global warming will disproportionally enhance the invasion success of A. artemisiifolia in Austria, even if there is only a slight increase in temperature, as significant areas of agricultural land in Austria are currently only slightly too cool for A. artemisiifolia. The widespread occurrence of this species will have serious consequences for human health and agriculture.
Free radicals and proinflammatory cytokines from phagocytes have been implicated in the pathogenesis of endotoxic shock, a disease with high mortality caused by Gram-negative bacterial endotoxin. In the present study, male BALB/c and Swiss mice received intraperitoneally lipopolysaccharide (LPS) at 100 mg/kg and 150 mg/kg, respectively, that led to a lethal endotoxic shock (100 % of mortality before 30 h). Swiss mice injected with 100 mg/kg, that did not show lethal endotoxic shock, were also studied. Peritoneal macrophages were obtained from animals at 2, 4, 12 or 24 h after injection of LPS or saline (control) solutions. Superoxide anion and tumor necrosis factor (TNFα) production were determined in these cells as well as other functions such as adherence capacity, chemotaxis and phagocytosis. The increase in superoxide anion production after endotoxin injection was higher in cells from mice with lethal shock than in those with non-lethal shock. However, the enhancement of TNFα production was similar in all cases, although in Swiss mice the highest levels of TNFα were observed at 1.5 h after endotoxin injection, while in BALB/c mice they occurred at 2 h after LPS injection. This oxidative stress was also revealed by the other functions analyzed, since adherence to substrate and phagocytosis were stimulated and chemotaxis was decreased after endotoxin injection as compared to controls, the differences being even more significant in animals with lethal shock. These data suggest that these changes, mainly the increased production of free radicals even more than the TNFα release, could be involved in mouse mortality caused by LPS., V. M. Víctor, M. de la Fuente., and Obsahuje bibliografii
Chloroplast polypeptide composition of rice plants {Oryza sativa L. cv. Safari) exposed for 30 d to increasing Cu ion concentrations in a hydroponie growth medium was analyised. The conventional discontinuous SDS-aerylamide gel electrophoretic systém, the SDS PhastGel (Pharmacia Fine Chemicals) gradient 10-15 and tíie 5-8 pH range polyaciylamide isoelectric focusing of the PhastSystem separation and development technique were ušed. With Cu levels greater than 0.25 g m'^ die polypeptide bands with apparent molecular masses of 42/41, 33/32, 21/20 and 19/18 kDa deereased in the PhastSystem separation and development systém, whereas with the conventional discontinuous SDS buffer systém gel electrophoresis all these bands disappeared except the 33/32 kDa band. Also, under the latter systém excess Cu deereased the 56/55, 55/54, 26 and 22 kDa bands which was not shown by the PhastSystem separation and development technique. Furthermore, in the discontinuous SDS-PAGE high Cu levels induced the disappearance of the 16.5, 14.5 and 12 kDa bands, which were again not shown by the PhastSystem separation and development technique; yet the opposite oceurred with the 49 kDa band of the gel profiles. Polyacrylamide isoelectric focusing of thyiakoid membranes showed in all Cu treatments two major bands at pl 7.7 and <5 and a minor one at pl 6.48. At Cu concentrations lower than 1.25 g m'^ two additional smáli bands appeared (pl 5.5 and 5.18); and at Cu concentrations greater than 0.25 g m'^ these smáli bands were replaced by four different ones (pl 6.7, 6.05, 5.35, 5.25).
The mixture of volatile compounds emitted by Brassica oleracea var. sabauda changed significantly in response to feeding and/or oviposition by Murgantia histrionica (Heteroptera: Pentatomidae). Volatiles were collected from (1) healthy plants and those with (2) feeding punctures, (3) a combination of feeding punctures and oviposition, (4) feeding punctures and one hatched egg mass and (5) plants bearing only an egg mass. In the case of plants with feeding punctures or feeding punctures plus an egg mass, the volatiles were also collected at different time intervals after plants were subjected to these two treatments (0-24 h, 24-48 h and 48-72 h). Gas chromatographic and gas chromatograph-mass spectrometric analysis showed that the percent emission of several compounds changed significantly from plants subjected to the feeding and oviposition or just oviposition. Percentage of terpenes generally decreased after feeding and oviposition, although the percentage emission of (E)-β-caryophyllene from these plants and those with just feeding punctures significantly increased. Plants with just an egg mass emitted linalool de novo but not (E)-β-ocimene. The emission of jasmonates, mainly methyl jasmonate, increased from plants with feeding punctures plus an egg mass compared to those with only an egg mass. Higher percentages of the volatile glucosinolate derivatives (VGSs), mainly 4-methoxy-3-indolylacetonitrile, were emitted by plants with feeding punctures and an egg mass. The percentage emission of most of these compounds increased during the first 24 h after the treatment and then decreased over the next 24 h, except for methyl jasmonate, which remained high also 48-72 h later. The possible ecological roles of such volatiles in plant interactions with the second and third trophic levels are discussed.
A comparison between maximum quantum yield of PSII photochemistry (Fv/Fm) and chlorophyll fluorescence decrease ratio (Rfd) for low and high temperature resistance was assessed in a seasonal study of the acclimation in Pterocephalus lasiospermus. Analyzing the regression adjustment of both parameters and the lethal temperatures (LT50), Rfd resulted in being a more sensitive indicator for low and high temperature treatments, since the thermic resistance estimated with Rfd parameter was never higher than those estimated with Fv/Fm. Furthermore, the use of Fv/Fm led to an overestimation of the acclimation phenomena, with 6ºC of a maximum difference between both parameters. Using Rfd as the indicator parameter, P. lasiospermus acclimated to low temperatures but it kept on being a sensitive species (the lowest LT50 values only achieved -9.9 ± 0.3ºC). However, no heat acclimation was observed (LT50 around 43.5ºC). Thus, according to Rfd evaluation of the thermic threshold, this species could be in risk of damage at low temperatures in this alpine ecosystem., A. V. Perera-Castro, P. Brito, A. M. González-Rodríguez., and Obsahuje bibliografii
Tissue differentiation and proliferation throughout fetal development interconnect with changes in the oxidative phosphorylation system (OXPHOS) on the cellular level. Reevaluation of the expression data revealed a significant increase in COX4 and MTATP6 liver transcription levels after the 22nd gestational week (GW) which inspired us to characterize its functional impact. Specific activities of cytochrome c oxidase (COX), citrate synthase (CS), succinate-coenzyme Q reductase (SQR) and mtDNA determined by spectrophotometry and RT-PCR were studied in a set of 25 liver and 18 skeletal muscle samples at 13th to 29th GW. Additionally, liver hematopoiesis (LH) was surveyed by light microscopy. The mtDNA content positively correlated with the gestational age only in the liver. The activities of COX, CS and SQR in both liver and muscle isolated mitochondria significantly decreased after the 22nd GW in comparison with earlier GW. A continuous decline of LH, not correlating with the documented OXPHOS-specific activities, was observed from the 14th to the 24th GW indicating their exclusive reflection of liver tissue processes. Two apparently contradictory processes of increasing mtDNA transcription and decreasing OXPHOS-specific activities seem to be indispensable for rapid postnatal adaptation to high energy demands. The inadequate capacity of mitochondrial energy production may be an important factor in the mortality of children born before the critical developmental point of the 22nd GW., H. Kolarová, J. Křížová, M. Hůlková, H. Hansiková, H. Hůlková, V. Smid, J. Zeman, T. Honzík, M. Tesarová., and Seznam literatury
French bean (Phaseolus vulgaris L.) cotyledons lost most of their reserve substances during several early days of germination and turned green. In cotyledon mesophyll cells of one-week-old seedlings, plastids were represented predominantly by amyloplasts (starch grains) and chloroamyloplasts, and the cells appeared to be metabolically highly active. Cell heterogeneity associated with distance of the cells from cotyledon vascular bundles was evident. Only mesophyll cells near to the bundles were rich in plastids. In two-weeks-old intact bean plants, the cotyledons were yellow and shrunken, and their cells were nearly "empty". The plastids in them were represented by senescent plastids (gerontoplasts) only. In the gerontoplasts as well as freely in cytosol, fluorescent lipoid inclusions were accumulated. This cotyledon development was more or less independent of irradiance. In "decapitated" bean plants, senescence of mesophyll cells and plastids was slowed down considerably, and the life span of the cotyledons was prolonged. and J. Kutík, N. Wilhelmová, J. Snopek.
Chlorophyll (Chl) fluorescence technique was ušed to monitor Cu damage in photosynthetic process in intact leaves of a Cu-tolerant {Silene conipacla) and a non- Cu-tolerant {Thlaspi ochroleucum) species. The initial fluorescence level (Fq) increased whereas the variable fluorescence (Fy) decreased in T. ochroleucum under low and high Cu-dose, suggesting injuries both in reaction centie level and in photooxidizing side of photosystem 2 (PS2). The photochemistiy activity of PS2, Fy/Fp, revealed a slight increase under 8 pM Cu in both species, while at 160 pM of Cu a strong inhibition in T. ochroleucum was observed. The Fp/F() ratio appeared to increase under low Cu dose, however the high Cu dose in nutrient solution resulted in damage to the thylakoid structure affecting the PS2 donor and acceptor side, mainly in T. ochroleucum. The slow part of the Chl fluorescence induction cuiwe was affected more by Cu stress, than the fast one. At low Cu concentration the Rfd value increased in S. compacla but decreased in T. ochroleucum. Fligh Cu dose induced an almost complete inhibition of this parameter, that was more severe in the non-tolerant plants. Yet, low Cu dose enhanced the Chl content in S. compacla but on exposure to 160 pM Cu the symptoms of chlorosis were more visible in T. ochroleucum. Thus, excess of Cu has direct negative effects on the photosynthetic electron transport that may be accounted for by the destruction of the photosynthetic pigments.
Water availability is a major limiting factor in desert ecosystems. However, a winter snowfall role in the growth of biological soil crusts is still less investigated. Here, four snow treatments were designed to evaluate the effects of snow depth on photosynthesis and physiological characteristics of biological soil crusts. Results showed that snow strongly affected the chlorophyll fluorescence properties. The increased snow depth led to increased contents of photosynthetic pigments and soluble proteins. However, all biological soil crusts also exhibited a decline in malondialdehyde and soluble sugar contents as snow increased. Results demonstrated that different biological soil crusts exhibited different responses to snow depth treatment due to differences in their morphological characteristics and microhabitat. In addition, interspecies differentiation in response to snow depth treatment might affect the survival of some biological soil crusts. Further, this influence might lead to changes in the structural composition and functional communities of biological soil crusts., R. Hui, R. M. Zhao, L. C. Liu, Y. X. Li, H. T. Yang, Y. L. Wang, M. Xie, X. Q. Wang., and Obsahuje bibliografii