Charissa de bekker

Charissa de bekker
University of Central Florida | UCF · Department of Biology

PhD

About

48
Publications
26,441
Reads
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1,348
Citations
Citations since 2016
21 Research Items
964 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Introduction
I am interested in the complexity of fungi displayed by their very dynamic transcriptome and metabolome. I currently study heterogeneous mechanisms employed by the entomopathogenic fungus Ophiocordyceps unilateralis, which is able to control the behavior of Camponotus ants upon infection, causing them to bite into vegetation before dying. By focussing on the fungal compounds causing this behavior, I aim to elucidate the complex mechanisms behind adaptive parasite manipulation of host behavior.
Additional affiliations
December 2016 - present
University of Central Florida
Position
  • Professor (Assistant)
Description
  • Molecular mechanisms underlying behavioral manipulation in Ophiocordyceps-ant interactions
September 2015 - December 2016
Ludwig-Maximilians-University of Munich
Position
  • Alexander von Humboldt Research Fellow
Description
  • Molecular mechanisms underlying behavioral manipulation in Ophiocordyceps-ant interactions
August 2014 - August 2015
Ludwig-Maximilians-University of Munich
Position
  • Post-doctoral Marie Curie Fellow
Description
  • Heterogeneous mechanisms underlying Ophiocordyceps- ant interactions
Education
October 2006 - September 2010
Utrecht University
Field of study
  • Biology
September 2004 - August 2006
Utrecht University
Field of study
  • Biomolecular Sciences
September 2001 - August 2004
Utrecht University
Field of study
  • Biology

Publications

Publications (48)
Article
Full-text available
Background: A compelling demonstration of adaptation by natural selection is the ability of parasites to manipulate host behavior. One dramatic example involves fungal species from the genus Ophiocordyceps that control their ant hosts by inducing a biting behavior. Intensive sampling across the globe of ants that died after being manipulated by Op...
Article
Full-text available
Co-evolution of parasites and their hosts has led to certain parasites adaptively manipulating the behavior of their hosts. Although the number of examples from different taxa for this phenomenon is growing, the mechanisms underlying parasite-induced manipulation of hosts’ behavior are still poorly understood. The development of laboratory infectio...
Article
Full-text available
Fungal entomopathogens rely on cellular heterogeneity during the different stages of insect host infection. Their pathogenicity is exhibited through the secretion of secondary metabolites, which implies that the infection life history of this group of environmentally important fungi can be revealed using metabolomics. Here metabolomic analysis in c...
Article
Full-text available
Single cell profiling was performed to assess differences in RNA accumulation in neighboring hyphae of the fungus Aspergillus niger. A protocol was developed to isolate and amplify RNA from single hyphae or parts thereof. Microarray analysis resulted in a present call for 4 to 7% of the A. niger genes, of which 12% showed heterogeneous RNA levels....
Article
1. Ophiocordyceps fungi manipulate the behavior of their ant hosts to produce a summit disease phenotype, thereby establishing infected ant cadavers onto vegetation at elevated positions suitable for fungal growth and transmission. Multiple environmental and ecological factors have been proposed to shape the timing, positioning, and outcome of thes...
Preprint
Full-text available
Ophiocordyceps fungi manipulate the behavior of their ant hosts to produce a summit disease phenotype, thereby establishing infected ant cadavers onto vegetation at elevated positions suitable for fungal growth and transmission. Multiple environmental and ecological factors have been proposed to shape the timing, positioning, and outcome of these m...
Preprint
Full-text available
Parasites and their hosts often share intimate coevolutionary relationship that can lead to bizarre phenotypes over time. Ophiocordyceps is one such genus that has evolved to manipulate the behavior of its various insect and arachnid hosts, the clearest examples of which are found in ants of the Camponotus tribe, colloquially known as zombie ants....
Preprint
Full-text available
Parasitic fungi are known to produce proteins that modulate virulence, alter host physiology, and trigger host responses. Due to their various effects on the host, these proteins are often considered a type of "effector" molecule, many of which act via protein-protein interactions (PPIs) between host and parasite. Cross-species PPIs between Ophioco...
Article
Full-text available
Ophiocordyceps fungi manipulate ant behavior as a transmission strategy. Conspicuous changes in the daily timing of disease phenotypes suggest that Ophiocordyceps and other manipulators could be hijacking the host clock. We discuss the available data that supports the notion that Ophiocordyceps fungi could be hijacking ant host clocks and consider...
Article
Full-text available
Background Circadian clocks allow organisms to anticipate daily fluctuations in their environment by driving rhythms in physiology and behavior. Inter-organismal differences in daily rhythms, called chronotypes, exist and can shift with age. In ants, age, caste-related behavior and chronotype appear to be linked. Brood-tending nurse ants are usuall...
Article
Full-text available
Transmission is a crucial step in all pathogen life cycles. As such, certain species have evolved complex traits that increase their chances to find and invade new hosts. Fungal species that hijack insect behaviors are evident examples. Many of these "zombie-making" entomopathogens cause their hosts to exhibit heightened activity, seek out elevated...
Article
Many parasites have evolved strategies to exploit host behaviour for successful transmission. Ophiocordyceps manipulations of carpenter ant behaviour represent an evident example. Manipulated ants are coerced to ascend vegetation and clamp down their mandibles in a stereotypical ‘death-grip’ bite. The fungus then kills the ant, sprouts a stalk and...
Preprint
Full-text available
Fungal hyperparasites can impact ecosystem composition and disease dynamics by modulating their parasite hosts’ population size and transmission rate. Despite their perceived ecosystem impacts and potential to be applied in disease control efforts, hyperparasites are vastly understudied. In this integrative study we formally describe a new genus an...
Preprint
Background Circadian clocks allow organisms to anticipate daily fluctuations in their environment by driving rhythms in physiology and behavior. Inter-organismal differences in daily rhythms, called chronotypes, exist and can shift with age. In ants, age, caste-related behavior and chronotype appear to be linked. “Around-the-clock” active nurse ant...
Article
Full-text available
Ant-infecting Ophiocordyceps fungi are globally distributed, host manipulating, specialist parasites that drive aberrant behaviors in infected ants, at a lethal cost to the host. An apparent increase in activity and wandering behaviors precedes a final summiting and biting behavior onto vegetation, which positions the manipulated ant in a site bene...
Preprint
Full-text available
A bstract The ant-infecting Ophiocordyceps fungi are globally distributed, host manipulating, specialist parasites that drive aberrant behaviors in infected ants, at a lethal cost to the host. An apparent increase in activity and wandering behaviors precedes a final summiting and biting behavior on to vegetation, positioning the manipulated ant in...
Article
Ophiocordyceps-infected ants display a substrate biting behavior that aids parasite transmission. World-wide research into this behavioral manipulation has led to new fungal species descriptions, annotated genomes, and detailed field observations. Experimentally tractable modified ant behaviors and the development of infection techniques have enabl...
Article
Biological rhythms coordinate organisms’ activities with daily rhythms in the environment. For parasites, this includes rhythms in both the external abiotic environment and the within-host biotic environment. Hosts exhibit rhythms in behaviours and physiologies, including immune responses, and parasites exhibit rhythms in traits underpinning virule...
Article
Specialized parasites can modify host behavior to benefit transmission and reproduction. Such behavior is considered an extended phenotype of the parasite. The interactions between certain ant species and fungi of the genus Ophiocordyceps form an evident example. Once infected by Ophiocordyceps camponoti-atricipis, Camponotus atriceps ants die, bit...
Article
Full-text available
Social insect colonies function cohesively due, in part, to altruistic behaviors performed towards related individuals. These colonies can be affected by parasites in two distinct ways, either at the level of the individual or the entire colony. As such, colonies of social insects can experience conflict with infected individuals reducing the cohes...
Article
Full-text available
Genome biology approaches have made enormous contributions to our understanding of biological rhythms, particularly in identifying outputs of the clock, including RNAs, proteins, and metabolites, whose abundance oscillates throughout the day. These methods hold significant promise for future discovery, particularly when combined with computational...
Article
Full-text available
Various parasite-host interactions that involve adaptive manipulation of host behavior display time-of-day synchronization of certain events. One example is the manipulated biting behavior observed in Carpenter ants infected with Ophiocordyceps unilateralis sensu lato. We hypothesized that biological clocks play an important role in this and other...
Article
Full-text available
Much can be gained from revealing the mechanisms fungal entomopathogens employ. Especially intriguing are fungal parasites that manipulate insect behavior because, presumably, they secrete a wealth of bioactive compounds. To gain more insight into their strategies, we compared the genomes of five ant-infecting Ophiocordyceps species from three spec...
Article
Parasites can manipulate the behavior of their hosts in ways that increase either their direct fitness or transmission to new hosts. The Kingdom Fungi have evolved a diverse array of strategies to manipulate arthropod behavior resulting in some of the most complex and impressive examples of behavioral manipulation by parasites. Here we provide an o...
Article
Full-text available
Adaptive manipulation of animal behavior by parasites functions to increase parasite transmission through changes in host behavior. These changes can range from slight alterations in existing behaviors of the host to the establishment of wholly novel behaviors. The biting behavior observed in Carpenter ants infected by the specialized fungus Ophioc...
Article
Full-text available
Colonies of Aspergillus niger are characterized by zonal heterogeneity in growth, sporulation, gene expression and secretion. For instance, the glucoamylase gene glaA is more highly expressed at the periphery of colonies when compared to the center. As a consequence, its encoded protein GlaA is mainly secreted at the outer part of the colony. Here,...
Article
Full-text available
Fungi are widely used as cell factories for the production of pharmaceutical compounds, enzymes and metabolites. Fungi form colonies that consist of a network of hyphae. During the last two decades it has become clear that fungal colonies within a liquid culture are heterogeneous in size and gene expression. Heterogeneity in growth, secretion, and...
Article
Full-text available
Black pigmented conidia of give rise to micro-colonies when incubated in liquid shaken medium. These micro-colonies are heterogeneous with respect to gene expression and size. We here studied the biophysical properties of the conidia of a control strain and of strains in which the or gene is inactivated. These strains form fawn-, olive-, and brown-...
Article
Mushrooms represent the most conspicuous structures of fungi. Their development is being studied in the model basidiomycete Schizophyllum commune. The genome of S. commune contains 472 genes encoding predicted transcription factors. Of these, fst3 and fst4 were shown to inhibit and induce mushroom development respectively. Here, we inactivated five...
Article
Full-text available
The fungus Aspergillus niger forms (sub)millimeter microcolonies within a liquid shaken culture. Here, we show that such microcolonies are heterogeneous with respect to size and gene expression. Microcolonies of strains expressing green fluorescent protein (GFP) from the promoter of the glucoamlyase gene glaA or the ferulic acid esterase gene faeA...
Article
Colonization of a substrate by fungi starts with the invasion of exploring hyphae. These hyphae secrete enzymes that degrade the organic material into small molecules that can be taken up by the fungus to serve as nutrients. We previously showed that only part of the exploring hyphae of Aspergillus niger highly express the glucoamylase gene glaA. T...
Article
Full-text available
Mycelial fungi use hyphae to colonize substrates. These hyphae secrete enzymes that convert complex polymers into breakdown products that can be taken up to serve as nutrients. Using GFP as a reporter it has been shown that exploring hyphae of Aspergillus niger are heterogenic with respect to expression of the glucoamylase gene glaA; some hyphae st...
Article
Schizophyllum commune is the only mushroom-forming fungus in which targeted gene deletions by homologous recombination have been reported. However, these deletions occur with a low frequency. To overcome this, the ku80 gene of S. commune was deleted. This gene is involved in the nonhomologous end-joining system for DNA repair. The Deltaku80 strain...
Article
Full-text available
Phleomycin is mutagenic by introducing double-strand breaks in DNA. The ble gene of Streptoalloteychus hindustanus, which confers resistance to this substance, is widely used as a selection marker for transformation. Schizophyllum commune grows on 25 μg of phleomycin ml−1 after introduction of a resistance cassette based on the ble gene. However, w...
Article
Novozym 234 has been traditionally used to prepare protoplasts for genetic transformation of fungi. Since it is no longer on the market, a new enzyme cocktail was defined to protoplast Aspergillus niger. The cocktail consists of lysing enzymes from Trichoderma harzianum, chitinase from Streptomyces griseus and beta-glucuronidase from Helix pomatia.
Article
Full-text available
Fungal mycelia are exposed to heterogenic substrates. The substrate in the central part of the colony has been (partly) degraded, whereas it is still unexplored at the periphery of the mycelium. We here assessed whether substrate heterogeneity is a main determinant of spatial gene expression in colonies of Aspergillus niger. This question was addre...
Article
Full-text available
The bacterial septum-located DNA translocase FtsK coordinates circular chromosome segregation with cell division. Rapid translocation of DNA by FtsK is directed by 8-base-pair DNA motifs (KOPS), so that newly replicated termini are brought together at the developing septum, thereby facilitating completion of chromosome segregation. Translocase func...

Questions

Questions (2)
Question
I am trying to identify proteins by running them on gel, silver staining, destaining, in-gel trypsin digestion, followed by peptide extraction and MS analysis. I have been doing this for the identification of single bands but I am wondering if it will work just as well for whole lanes at once, that contain a lot of bands.
Question
I have field samples that I freeze in liquid nitrogen to stop all processes at a certain time point and want to use for transcriptomics. However, I will have to ship them which probably can't be done frozen since I don't know how long they will sit at the border so they might perish. Is it a good idea to keep them in ethanol for instance?

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