Abstract Malaria vaccination approaches using live Plasmodium parasites are currently explored, with either attenuated mosquito-derived sporozoites or attenuated blood-stage parasites. Both ...approaches would profit from the availability of attenuated and avirulent parasites with a reduced blood-stage multiplication rate. Here we screened gene-deletion mutants of the rodent parasite P. berghei and the human parasite P. falciparum for slow growth. Furthermore, we tested the P. berghei mutants for avirulence and resolving blood-stage infections, while preserving sporozoite formation and liver infection. Targeting 51 genes yielded 18 P. berghei gene-deletion mutants with several mutants causing mild infections. Infections with the two most attenuated mutants either by blood stages or by sporozoites were cleared by the immune response. Immunization of mice led to protection from disease after challenge with wild-type sporozoites. Two of six generated P. falciparum gene-deletion mutants showed a slow growth rate. Slow-growing, avirulent P. falciparum mutants will constitute valuable tools to inform on the induction of immune responses and will aid in developing new as well as safeguarding existing attenuated parasite vaccines.
Ecologists, particularly restoration ecologists, were early to recognise the challenges of historically unprecedented combinations of species and abiotic conditions brought about by human ...intervention. However, to date, this ecological understanding has paid limited attention to
sociocultural considerations. We propose the concept of novel natures to combine ecological and social dimensions in the perception and evaluation of novelty in nature, and to assist conservation and restoration decision-making in a time of rapid environmental change.
The malaria parasite Plasmodium depends on its actin‐based motor system for motility and host‐cell invasion. Actin‐depolymerization factors are important regulatory proteins that affect the rate of ...actin turnover. Plasmodium has two actin‐depolymerization factors which seem to have different functions and display low sequence homology to the higher eukaryotic family members. Plasmodium actin‐depolymerization factors 1 and 2 have been crystallized. The crystals diffracted X‐rays to maximum resolutions of 2.0 and 2.1 Å and belonged to space groups P3121 or P3221, with unit‐cell parameters a = b = 68.8, c = 76.0 Å, and P21212, with unit‐cell parameters a = 111.6, b = 57.9, c = 40.5 Å, respectively, indicating the presence of one or two molecules per asymmetric unit in both cases.
Actin regulation in the malaria parasite Sattler, Julia Magdalena; Ganter, Markus; Hliscs, Marion ...
European journal of cell biology,
11/2011, Letnik:
90, Številka:
11
Journal Article
Recenzirano
Many intracellular pathogens hijack host cell actin or its regulators for cell-to-cell spreading. In marked contrast, apicomplexan parasites, obligate intracellular, single cell eukaryotes that are ...phylogenetically older than the last common ancestor of animals and plants, employ their own actin cytoskeleton for active motility through tissues and invasion of host cells. A hallmark of actin-based motility of the malaria parasite is a minimal set of proteins that potentially regulate microfilament dynamics. An intriguing feature of the
Plasmodium motor machinery is the virtual absence of elongated filamentous actin
in vivo. Despite this unusual actin regulation sporozoites, the transmission stages that are injected into the mammalian host by
Anopheles mosquitoes, display fast (1–3
μm/s) extracellular motility. Experimental genetics and analysis of recombinant proteins have recently contributed to clarify some of the cellular roles of apicomplexan actin monomer- and filament-binding proteins in parasite life cycle progression. These studies established that the malaria parasite employs multiple proteins that bind actin to form pools of readily polymerizable monomers, a prerequisite for fast formation of actin polymers. The motile extracellular stages of
Plasmodium parasites are an excellent
in vivo model system for functional characterization of actin regulation in single cell eukaryotes.
In this investigation, we studied whether genetic variation and performance of the alpine plant species
Dianthus callizonus
differ between two different elevational zones of the southern Carpathians ...in Romania. We analysed 17 populations of the species from two study regions at 1700 and 2100 m above sea level in the Piatra Craiului Mountains applying AFLP analyses and morphological measurements. Following our results, population size differed between the two study regions and genetic variation within populations depended on population size. Population size and genetic variation within populations were higher in the study region located at 1700 m. By contrast, genetic variation between populations was nearly twice as large in the study region located at 2100 m. In a Mantel test, genetic and geographic distances between populations were clearly correlated. Moreover, individuals from the study region at 2100 m were significantly smaller, had fewer shoots, fewer flowers per shoot and produced seeds with a lower seed mass than individuals from the study region at 1700 m. The results of our study support the observation that changing environmental conditions along elevational gradients in mountain regions affect population size, genetic variation and performance of alpine plant species from different elevational zones, which should be considered in plant conservation.
Ecologists, particularly restoration ecologists, were early to recognise the challenges of historically unprecedented combinations of species and abiotic conditions brought about by human ...intervention. However, to date, this ecological understanding has paid limited attention to
sociocultural considerations. We propose the concept of novel natures to combine ecological and social dimensions in the perception and evaluation of novelty in nature, and to assist conservation and restoration decision-making in a time of rapid environmental change.
In the last two decades, translation has become a significant topic in literary and cultural studies as well as in the humanities at large. Following the disappearance of the hugely limiting Cold War ...bipolar division of the world, the emerging multi-polarity has provided a fresh impetus to not only engage in translation far beyond the traditional classical Eurocentric perspective but also to think about translation as a mode of acting in this new world. Following Emily Apter's fascinating metaphor of the "translation zone," the significance of translation and translation studies has been described as growing "in importance as the material and social structures of our world became more global; with the spread of financial, information, and military networks; with an increasing migration of peoples; and with war ..." (Berman 83n). Adapted from the source document
Metropolitan Research Jens Martin Gurr, Rolf Parr, Dennis Hardt / Jens Martin Gurr, Rolf Parr, Dennis Hardt
2022
eBook
Odprti dostop
Metropolitan research requires multidisciplinary perspectives in order to do justice to the complexities of metropolitan regions. This volume provides a scholarly and accessible overview of key ...methods and approaches in metropolitan research from a uniquely broad range of disciplines including architectural history, art history, heritage conservation, literary and cultural studies, spatial planning and planning theory, geoinformatics, urban sociology, economic geography, operations research, technology studies, transport planning, aquatic ecosystems research and urban epidemiology. It is this scope of disciplinary - and increasingly also interdisciplinary - approaches that allows metropolitan research to address recent societal challenges of urban life, such as mobility, health, diversity or sustainability.
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