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Whole effluent toxicity is most often considered as a static parameter. However, toxicity might change as degradation processes, especially biodegradation goes by and intermediate products appear. These intermediates can even be more toxic than the original effluent was, posing higher risk to the ecosystem of the recipient water body. In our test series it was assessed how toxicity of a municipal wastewater sample changes during biodegradation taking into consideration different temperature regimes (10, 20 and 30 °C). Results proved our null hypothesis: after the high initial toxicity of the fresh effluent sample toxicity did show a further increase. Biodegradation resulted in toxicity reduction only after an approx. 2 week-period.
Species richness, resource availability, and disturbance are the primary factors considered in assessing the invasibility of plant communities. Nonetheless, the density of individuals in a community is a common and easy trait to measure. The ecological significance of the density of both native and invasive tree species was assessed using a systematic review and formal meta-analysis. The densities of recipient communities and invasive exotic tree species in novel ranges were identified in the published literature. In addition, we compared by means of a meta-analysis: (i) densities of invasive versus native species in invaded communities; (ii) densities of native species in invaded versus uninvaded communities; and (iii) densities of invasive species along distance gradients from initial locus of invasion. Invasive trees were found at higher densities than native species in recipient communities. Invasions by woody species were also recorded in communities with relatively low densities of natives suggesting that (i) low density forests may be more susceptible to invasion and/or (ii) density of the recipient community may be reduced during the invasion process. In addition, comparison of native species densities between invaded and uninvaded stands from the same community suggests that invasive trees negatively affect density of native trees once established. Therefore, the widely reported low density and often richness of native plants in invaded communities cannot be directly linked to ecosystem susceptibility to invasion without considering concomitant impacts. These findings suggest that density is a key preliminary determinant or factor which should be considered when assessing tree invasion dynamics.
Although significant progress has been made on Agrobacterium-mediated wheat transformation, current methodologies using immature embryos as recipient tissues are labor intensive, time consuming and expensive. The use of mature embryos as explants is increasingly being recognized as an optimal method for developing regenerable cell lines during wheat transformation. Therefore, we have developed an Agrobacterium-based transformation protocol using mature embryos while adjusting several factors that influence genetic transformation efficiency. In this study, we focussed on acetosyringone concentrations, genotypes and different types of mature embryos (intact or longitudinally halved-embryos or fragmented into four latitudinal pieces) used as a source of explants for the genetic transformation. A. tumefaciens strain EHA101 harboring the plasmid vector pTF101.1 carrying the barley HVA1 gene and bar-selectable marker gene were used. Mature intact-embryos and longitudinally halved-embryos yielded the highest number of putative transgenic plantlets on the selection medium. However, no plantlets were obtained from latitudinal fragmented mature embryos. ‘Amal’ and ‘Rajae’ genotypes regenerated the highest number of putative transgenic plants and 200 μM acetosyringone was found to be the optimal concentration for their transformation. A total of 47 transgenic plants were selected with 11 plantlets showing resistance to leaf painting. Molecular analysis revealed that 1% and 0.66% of T0 regenerated plantlets were successfully transformed and carried the HVA1 gene for the ‘Amal’ and ‘Rajae’ genotypes, respectively. Additional analysis shows the transgene is stably inherited in the T1 generation. Based on the results, we conclude that among the influencing factors tested, genotypes, mature embryo explant types and acetosyringone concentration contribute significantly to the success of bread wheat transformation.
Birdseye primrose (Primula farinosa subsp. alpigena) is a strictly protected plant species of the Hungarian flora. Natural occurrences of the species are known from two fen meadows situated in a tectonic depression accompanying Lake Balaton. The restoration and management of recipient vegetation have a great importance because of the wide range fluctuation in number of individuals of the species for several years. In 2001 coenological behaviour was examined in classical and meso scale. Field data were collected by modified Zürich-Montpellier method and 1 m × 1 m quadrats as transects marked by environmental gradients with cover estimation by eye collecting presence-absence and quantitative data. Examining the classical and transect quadrats ecological indication, preferences and significance between species and habitats were revealed focusing on Birdseye primrose. In addition 8 soil parameters were analysed in Primula rich and Primula free sites of the habitats. The aim of our investigation was to broaden the knowledge about the biotic and abiotic habitat preferences of Birdseye primrose. According to our results not only the textural features (e.g. species composition, abundance) are insufficiant to save this species from extinction but the pattern and physiognomy of vegetation have more significance. The tussock-fen window complex provides prominent situation with its nudum surfaces offering favourable abiotic conditions and low competition. The effects of other characteristics of preferential sites (e.g. gap size, litter or moss cover) in micro scale are substantial in all probability. With this knowledge restoration and managing plan were executed focusing on two aspects: the maintenance of population size via directed seed dispersion and plantation and controlling of biotic as well as abiotic factors in the natural habitats.
Naturalization is the introduction and establishment of a nonnative species with sustainable populations in a novel environment. The success of nonnative species may be influenced by their relatedness to the native flora. Darwin proposed that if a nonnative plant species is introduced into an environment without native congeners, the nonnative species will have a greater chance of becoming naturalized. To test Darwin’s naturalization hypothesis, we compiled a Kentucky plant database consisting of 821 vascular plant species and subsequently selected species traits and distribution information to determine the effect of congeneric species and traits on the probability of successful naturalization and invasion. The predictors used include reproductive traits, growth form, abundance, habitat type, native congeners, and biogeographical origin. We fit three sets of generalized linear mixed models (GLMMs) with a binomial family and a logit link. Backward selection based on minimizing the Akaike Information Criterion (AIC) was used in the analyses. Our results from these three sets of models clearly indicate that the validity of Darwin’s hypothesis is invasion stage dependent. More specific, the naturalized and invasive models (predicting the probability of being naturalized and invasive respectively) did not support Darwin’s naturalization hypothesis. The number of native congeners had no effect on the likelihood that a particular species would naturalize and become invasive. Our results suggest that Darwin’s naturalization hypothesis is more relevant during the early stage of establishment as demonstrated by the native model (predicting the probability of being native) and it becomes irrelevant during the late stages of invasion as indicated by the naturalized and invasive models. Thus, it can be generalized that biotic interactions, especially competition, is a critical determinant of initial success for nonnative species in the recipient communities. Once established, the fate of non-native species during the late stages of invasion may be more related to other factors such as biogeographic origin and habitat conditions. Furthermore, we found reproductive traits such as flowering phenology and flower type are associated with invasion success. We also recognized contrasting traits between native and nonnative species, indicating niche differentiation between these two groups of species. Niche overlapping was found as well among species regardless of the status of being native or otherwise. Our study provides a novel approach to advance the understanding of phylogenetic relatedness between nonnative species and native flora by integrating traits and niche concepts at the regional scale.
Nucci, M. (2003) Emerging moulds: Fusarium , Scedosporium and Zygomycetes in transplant recipients. Curr. Opin. Infect. Dis. 16 , 607–612. Nucci M. Emerging moulds
. 6. Crabol , Y. , Lortholary , O. ( 2014 ) Invasive mold infections in solid organ transplant recipients . Scientifica 2014 , 821969 . 7
) Fungal brain abscess in transplant recipients: epidemiologic, microbiologic, and clinical features. Clin. Transplant. 16 , 419–424. Pappas P. G. Fungal brain abscess in transplant
are involved in the parasite transmission to seronegative recipients. It is unclear whether T. gondii can be transmitted by surgical procedures other than organ transplant. It is also unknown whether the use of contaminated materials during surgery
species. ESX-4 The ESX-4 system is involved in the secretion of effectors that are required in the conjugation process, especially in the mycobacterial receiver strains. From a donor: recipient co-culture study, an ESX-1 mediated expression of ESX-4 genes
