Conference Presentations by Ulrike Kappler
The first recommendation of The Boyer Commission Report (1998) was that research-based learning b... more The first recommendation of The Boyer Commission Report (1998) was that research-based learning be made the standard experience for students at university. Two other key recommendations were that universities (i) link communication skills to coursework; and (ii) use information technology creatively. The Australian university system has come a long way since 1998, but if we compare our tertiary sector to the USA, we still have a long way to go before our students have large-scale access to apprenticeship-style UREs, and avenues for communicating their findings. The ALURE project has been funded for 2013-2015 under the OLT National Leadership initiative. It uses a Community of Practice (CoP) to develop and resource academics to help students conduct and communicate undergraduate research on a large scale. The current foci for the programme are science and maths students and the academics who teach them. In this showcase the project team will introduce a ‘checklist’ that has been developed to guide academics through necessary considerations when developing an ALURE. A number of our ALURE CoP members will present the undergraduate research programmes they have devised and championed. These programmes have been implemented in a variety of disciplines and some have been running for many years whilst others have recently completed their first implementation. The project has developed a method for evaluating the impact of the programmes and will present the outcomes achieved from the ALUREs that have been implemented by CoP members.
The practical laboratory is central to science education, and all undergraduate students will spend considerable time (up to half of their contact hours) in the teaching laboratory. For students who experience well-designed teaching programs, the teaching laboratory can be an exciting place of challenge, discovery, and collaboration. Too often, however, this is not the case. The learning objectives of an ALURE and the method for selecting the research topic allow variation in the amount of independence the students have and the level of creativity they are expected to contribute. Accordingly, a large-scale project in the undergraduate laboratory may allow students more scope to learn and practice varied laboratory skills, to synthesise a question themselves, and perhaps to design their own experimental methods. We submit that research experience for students, before they attempt to enter a professional research laboratory at the late second-, third-, or Honours-year level creates better, more productive students who are more confident working with the complexity and uncertainty associated with research. We will also highlight the additional support needs of students that arise from the additional level of independence and creativity inherent in an ALURE program.
Bookmarks Related papers MentionsView impact
Papers by Ulrike Kappler
Antioxidants
Sulfoxide-damage repair mechanisms are emerging as essential for the virulence of bacterial patho... more Sulfoxide-damage repair mechanisms are emerging as essential for the virulence of bacterial pathogens, and in the human respiratory pathogen Haemophilus influenzae the periplasmic MsrAB peptide methionine sulfoxide reductase is necessary for resistance to reactive chlorine species such as hypochlorite. Additionally, this enzyme has a role in modulating the host immune response to infection. Here, we have analysed the enzymatic properties of MsrAB, which revealed that both domains of the protein are catalytically active, with the turnover number of the MsrA domain being 50% greater than that for the MsrB domain. MsrAB was active with small molecular sulfoxides as well as oxidised calmodulin, and maximal activity was observed at 30°C, a temperature close to that found in the natural niche of H. influenzae, the nasopharynx. Analyses of differential methionine oxidation identified 29 outer membrane and periplasmic proteins that are likely substrates for MsrAB. These included the LldD la...
Bookmarks Related papers MentionsView impact
Trabajo presentado en las XII Jornadas de Formacion del Centro de Investigacion Biomedica en Red ... more Trabajo presentado en las XII Jornadas de Formacion del Centro de Investigacion Biomedica en Red de Enfermedades Respiratorias (CIBERES), celebradas en Madrid (Espana), el 27 de septiembre de 2019
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Phytopathology, 2018
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Molecules, 2021
The volatile organic sulfur compound allicin (diallyl thiosulfinate) is produced as a defense sub... more The volatile organic sulfur compound allicin (diallyl thiosulfinate) is produced as a defense substance when garlic (Allium sativum) tissues are damaged, for example by the activities of pathogens or pests. Allicin gives crushed garlic its characteristic odor, is membrane permeable and readily taken up by exposed cells. It is a reactive thiol-trapping sulfur compound that S-thioallylates accessible cysteine residues in proteins and low molecular weight thiols including the cellular redox buffer glutathione (GSH) in eukaryotes and Gram-negative bacteria, as well as bacillithiol (BSH) in Gram-positive firmicutes. Allicin shows dose-dependent antimicrobial activity. At higher doses in eukaryotes allicin can induce apoptosis or necrosis, whereas lower, biocompatible amounts can modulate the activity of redox-sensitive proteins and affect cellular signaling. This review summarizes our current knowledge of how bacterial and eukaryotic cells are specifically affected by, and respond to, al...
Bookmarks Related papers MentionsView impact
Frontiers in Microbiology, 2020
Mononuclear molybdoenzymes are highly versatile catalysts that occur in organisms in all domains ... more Mononuclear molybdoenzymes are highly versatile catalysts that occur in organisms in all domains of life, where they mediate essential cellular functions such as energy generation and detoxification reactions. Molybdoenzymes are particularly abundant in bacteria, where over 50 distinct types of enzymes have been identified to date. In bacterial pathogens, all aspects of molybdoenzyme biology such as molybdate uptake, cofactor biosynthesis, and function of the enzymes themselves, have been shown to affect fitness in the host as well as virulence. Although current studies are mostly focused on a few key pathogens such asEscherichia coli, Salmonella enterica, Campylobacter jejuni, andMycobacterium tuberculosis, some common themes for the function and adaptation of the molybdoenzymes to pathogen environmental niches are emerging. Firstly, for many of these enzymes, their role is in supporting bacterial energy generation; and the corresponding pathogen fitness and virulence defects appea...
Bookmarks Related papers MentionsView impact
Journal of Biological Chemistry, 2021
Cryptococcus neoformans is a fungus that causes life-threatening systemic mycoses. During infecti... more Cryptococcus neoformans is a fungus that causes life-threatening systemic mycoses. During infection of the human host, this pathogen experiences a major change in the availability of purines; the fungus can scavenge the abundant purines in its environmental niche of pigeon excrement, but must employ de novo biosynthesis in the purine-poor human CNS. Eleven sequential enzymatic steps are required to form the first purine base, IMP, an intermediate in the formation of ATP and GTP. Over the course of evolution, several gene fusion events led to the formation of multifunctional purine biosynthetic enzymes in most organisms, particularly the higher eukaryotes. In C. neoformans, phosphoribosyl-glycinamide synthetase (GARs) and phosphoribosyl-aminoimidazole synthetase (AIRs) are fused into a bifunctional enzyme, while the human ortholog is a trifunctional enzyme that also includes GAR transformylase. Here we functionally, biochemically, and structurally characterized C. neoformans GARs and AIRs to identify drug targetable features. GARs/AIRs are essential for de novo purine production and virulence in a murine inhalation infection model. Characterization of GARs enzymatic functional parameters showed that C. neoformans GARs/AIRs have lower affinity for substrates glycine and PRA compared with the trifunctional metazoan enzyme. The crystal structure of C. neoformans GARs revealed differences in the glycine- and ATP-binding sites compared with the Homo sapiens enzyme, while the crystal structure of AIRs shows high structural similarity compared with its H. sapiens ortholog as a monomer but differences as a dimer. The alterations in functional and structural characteristics between fungal and human enzymes could potentially be exploited for antifungal development.
Bookmarks Related papers MentionsView impact
Advances in Microbial Physiology, 2019
Sulfoxides occur in biology as products of the S-oxygenation of small molecules as well as in pep... more Sulfoxides occur in biology as products of the S-oxygenation of small molecules as well as in peptides and proteins and their formation is often associated with oxidative stress and can affect biological function. In bacteria, sulfoxide damage can be reversed by different types of enzymes. Thioredoxin-dependent peptide methionine sulfoxide reductases (MSR proteins) repair oxidized methionine residues and are found in all Domains of life. In bacteria MSR proteins are often found in the cytoplasm but in some bacteria, including pathogenic Neisseria, Streptococci, and Haemophilus they are extracytoplasmic. Mutants lacking MSR proteins are often sensitive to oxidative stress and in pathogens exhibit decreased virulence as indicated by reduced survival in host cell or animal model systems. Molybdenum enzymes are also known to reduce S-oxides and traditionally their physiological role was considered to be in anaerobic respiration using dimethylsulfoxide (DMSO) as an electron acceptor. However, it now appears that some enzymes (MtsZ) of the DMSO reductase family of Mo enzymes use methionine sulfoxide as preferred physiological substrate and thus may be involved in scavenging/recycling of this amino acid. Similarly, an enzyme (MsrP/YedY) of the sulfite oxidase family of Mo enzymes has been shown to be involved in repair of methionine sulfoxides in periplasmic proteins. Again, some mutants deficient in Mo-dependent sulfoxide reductases exhibit reduced virulence, and there is evidence that these Mo enzymes and some MSR systems are induced by hypochlorite produced by the innate immune system. This review describes recent advances in the understanding of the molecular microbiology of MSR systems and the broadening of the role of Mo-dependent sulfoxide reductase to encompass functions beyond anaerobic respiration.
Bookmarks Related papers MentionsView impact
Frontiers in Microbiology, 2019
Bookmarks Related papers MentionsView impact
Pathogens and Disease, 2019
Non-typeable Haemophilus influenzae (NTHi) is a major pathogen in upper and lower respiratory tra... more Non-typeable Haemophilus influenzae (NTHi) is a major pathogen in upper and lower respiratory tract infections in humans, and is increasingly also associated with invasive disease. We have examined two unrelated NTHi invasive disease isolates, R2866 and C188, in order to identify metabolic and physiological properties that distinguish them from respiratory tract disease isolates such as Hi2019. While the general use of the Hi metabolic network was similar across all three strains, the two invasive isolates secreted increased amounts of succinate, which can have anti-inflammatory properties. In addition, they showed a common shift in their carbon source utilization patterns, with strongly enhanced metabolism of nucleoside substrates, glucose and sialic acid. The latter two are major compounds present in blood and cerebrospinal fluid (CSF). Interestingly, C188 and R2866 also shared a reduced ability to invade or survive intracellularly in 16HBE14 bronchial epithelial cells relative to...
Bookmarks Related papers MentionsView impact
Biochimica et biophysica acta, 2018
A central conserved arginine, first identified as a clinical mutation leading to sulfite oxidase ... more A central conserved arginine, first identified as a clinical mutation leading to sulfite oxidase deficiency, is essential for catalytic competency of sulfite oxidizing molybdoenzymes, but the molecular basis for its effects on turnover and substrate affinity have not been fully elucidated. We have used a bacterial sulfite dehydrogenase, SorT, which lacks an internal heme group, but transfers electrons to an external, electron accepting cytochrome, SorU, to investigate the molecular functions of this arginine residue (Arg78). Assay of the SorT Mo centre catalytic competency in the absence of SorU showed that substitutions in the central arginine (R78Q, R78K and R78M mutations) only moderately altered SorT catalytic properties, except for R78M which caused significant reduction in SorT activity. The substitutions also altered the Mo-centre redox potentials (MoVI/V potential lowered by ca. 60-80mV). However, all Arg78 mutations significantly impaired the ability of SorT to transfer ele...
Bookmarks Related papers MentionsView impact
Genome announcements, Jan 23, 2017
Nontypeable Haemophilus influenzae is a persistent human respiratory pathogen known to be involve... more Nontypeable Haemophilus influenzae is a persistent human respiratory pathogen known to be involved in a range of acute and chronic respiratory diseases. Here, we report the genome sequences of three H. influenzae strains isolated from sputum, otitis media, and blood. Comparative analyses revealed significant differences in the gene contents including the presence of genes mediating antibiotic resistance.
Bookmarks Related papers MentionsView impact
The Journal of biological chemistry, Jul 30, 2017
There is significant clinical need for new antifungal agents to manage infections with pathogenic... more There is significant clinical need for new antifungal agents to manage infections with pathogenic species such as Cryptococcus neoformans Because the purine biosynthesis pathway is essential for many metabolic processes, such as synthesis of DNA and RNA and energy generation, it may represent a potential target for developing new antifungals. Within this pathway, the bifunctional enzyme adenylosuccinate (ADS) lyase plays a role in the formation of the key intermediates inosine monophosphate and AMP involved in the synthesis of ATP and GTP, prompting us to investigate ADS lyase in C. neoformans Here, we report that ADE13 encodes ADS lyase in C. neoformans We found that an ade13Δ mutant is an adenine auxotroph and is unable to successfully cause infections in a murine model of virulence. Plate assays revealed that production of a number of virulence factors essential for dissemination and survival of C. neoformans in a host environment was compromised even with the addition of exogeno...
Bookmarks Related papers MentionsView impact
Frontiers in microbiology, 2017
Concrete corrosion is one of the most significant problems affecting valuable sewer infrastructur... more Concrete corrosion is one of the most significant problems affecting valuable sewer infrastructure on a global scale. This problem occurs in the aerobic zone of the sewer, where a layer of surface corrosion develops on the exposed concrete and the surface pH is typically lowered from around 11-10 (pristine concrete) to pH 2-4. Acidophilic microorganisms become established as biofilms within the concrete corrosion layer and enhance the loss of concrete mass. Until recently, the acidophilic community was considered to comprise relatively few species of microorganisms, however, the biodiversity of the corrosion community is now recognized as being extensive and varying from different sewer environmental conditions. The diversity of acidophiles in the corrosion communities includes chemolithoautotrophs, chemolithoheterotrophs, and chemoorganoheterotrophs. The activity of these microorganisms is strongly affected by H2S levels in the sewer gas phase, although CO2, organic matter, and iro...
Bookmarks Related papers MentionsView impact
The Journal of biological chemistry, Feb 17, 2017
Over the last four decades the HIV pandemic and advances in medical treatments that also cause im... more Over the last four decades the HIV pandemic and advances in medical treatments that also cause immunosuppression have produced an ever-growing cohort of individuals susceptible to opportunistic pathogens. Of these, AIDS patients are particularly vulnerable to infection by the encapsulated yeast Cryptococcus neoformans Most commonly found in the environment in purine-rich bird guano, C. neoformans experiences a drastic change in nutrient availability during host infection, ultimately disseminating to colonize the purine-poor central nervous system. Investigating the consequences of this challenge, we have characterized C. neoformans GMP synthase, the second enzyme in the guanylate branch of de novo purine biosynthesis. We show that in the absence of GMP synthase, C. neoformans becomes a guanine auxotroph, the production of key virulence factors is compromised, and the ability to infect nematodes and mice is abolished. Activity assays performed using recombinant protein unveiled diffe...
Bookmarks Related papers MentionsView impact
Frontiers in microbiology, 2016
Haemophilus influenzae is a host adapted human mucosal pathogen involved in a variety of acute an... more Haemophilus influenzae is a host adapted human mucosal pathogen involved in a variety of acute and chronic respiratory tract infections, including chronic obstructive pulmonary disease and asthma, all of which rely on its ability to efficiently establish continuing interactions with the host. Here we report the characterization of a novel molybdenum enzyme, TorZ/MtsZ that supports interactions of H. influenzae with host cells during growth in oxygen-limited environments. Strains lacking TorZ/MtsZ showed a reduced ability to survive in contact with epithelial cells as shown by immunofluorescence microscopy and adherence/invasion assays. This included a reduction in the ability of the strain to invade human epithelial cells, a trait that could be linked to the persistence of H. influenzae. The observation that in a murine model of H. influenzae infection, strains lacking TorZ/MtsZ were almost undetectable after 72 h of infection, while ∼3.6 × 10(3) CFU/mL of the wild type strain were ...
Bookmarks Related papers MentionsView impact
ACS Infectious Diseases, 2016
Opportunistic fungal pathogens such as Cryptococcus neoformans are a growing cause of morbidity a... more Opportunistic fungal pathogens such as Cryptococcus neoformans are a growing cause of morbidity and mortality among immunocompromised populations worldwide. To address the current paucity of antifungal therapeutic agents, further research into fungal-specific drug targets is required. Adenylosuccinate synthetase (AdSS) is a crucial enzyme in the adeosine triphosphate (ATP) biosynthetic pathway, catalyzing the formation of adenylosuccinate from inosine monophosphate and aspartate. We have investigated the potential of this enzyme as an antifungal drug target, finding that loss of function results in adenine auxotrophy in C. neoformans, as well as complete loss of virulence in a murine model. Cryptococcal AdSS was expressed and purified in Escherichia coli and the enzyme's crystal structure determined, the first example of a structure of this enzyme from fungi. Together with enzyme kinetic studies, this structural information enabled comparison of the fungal enzyme with the human orthologue and revealed species-specific differences potentially exploitable via rational drug design. These results validate AdSS as a promising antifungal drug target and lay a foundation for future in silico and in vitro screens for novel antifungal compounds.
Bookmarks Related papers MentionsView impact
Uploads
Conference Presentations by Ulrike Kappler
The practical laboratory is central to science education, and all undergraduate students will spend considerable time (up to half of their contact hours) in the teaching laboratory. For students who experience well-designed teaching programs, the teaching laboratory can be an exciting place of challenge, discovery, and collaboration. Too often, however, this is not the case. The learning objectives of an ALURE and the method for selecting the research topic allow variation in the amount of independence the students have and the level of creativity they are expected to contribute. Accordingly, a large-scale project in the undergraduate laboratory may allow students more scope to learn and practice varied laboratory skills, to synthesise a question themselves, and perhaps to design their own experimental methods. We submit that research experience for students, before they attempt to enter a professional research laboratory at the late second-, third-, or Honours-year level creates better, more productive students who are more confident working with the complexity and uncertainty associated with research. We will also highlight the additional support needs of students that arise from the additional level of independence and creativity inherent in an ALURE program.
Papers by Ulrike Kappler
The practical laboratory is central to science education, and all undergraduate students will spend considerable time (up to half of their contact hours) in the teaching laboratory. For students who experience well-designed teaching programs, the teaching laboratory can be an exciting place of challenge, discovery, and collaboration. Too often, however, this is not the case. The learning objectives of an ALURE and the method for selecting the research topic allow variation in the amount of independence the students have and the level of creativity they are expected to contribute. Accordingly, a large-scale project in the undergraduate laboratory may allow students more scope to learn and practice varied laboratory skills, to synthesise a question themselves, and perhaps to design their own experimental methods. We submit that research experience for students, before they attempt to enter a professional research laboratory at the late second-, third-, or Honours-year level creates better, more productive students who are more confident working with the complexity and uncertainty associated with research. We will also highlight the additional support needs of students that arise from the additional level of independence and creativity inherent in an ALURE program.