Shifting from or supplementing traditional cultures by offering PCR infectious disease testing can be challenging for a laboratory. The addition of this testing is not just a change for the lab, but also for the ordering physicians used to conventional methods. However, that also offers an opportunity to add value to your customers and your lab if you focus on answering three basic questions: Is it good science? Will they use it? And will you get paid? The goal of this presentation is to help answer those questions and to aid in developing practical strategies when on boarding this technology through the example of Wise Diagnostic Systems.

Laboratories performing diagnostic testing for infectious diseases have an obligation to meet the needs of multiple patient populations. With infectious disease, time it takes for reporting can have many implications, mainly in terms of infection control, prevention of spread, reduction of healthcare and other associated costs and applying the right treatment in a timely manner. In addition, laboratories must be equipped with testing mechanisms that are sensitive, specific and affordable to their operation.

Putting our focus on gastrointestinal diseases, stool culture has for long been the standard in diagnosing an infection. However, in recent years, many laboratories have started adopting PCR-based panels to test for infections with gastrointestinal pathogens. But what would be a good way to transition from stool culture to PCR?

With molecular testing being adopted as the first stop for testing for many infectious diseases, it is important to discuss best practices and how introducing molecular testing for gastrointestinal infections can allow laboratories to operate efficiently, while at the same time fulfilling the needs of the public. Join us for a discussion with Dr Michael Perry, Deputy Lead Scientist at the UK Anaerobe Reference Unit, Public Health Wales Microbiology Cardiff, to learn from his experience leading an important laboratory and what best practices can by adopted for laboratorians looking to transition from culture to molecular diagnostics.

Learning Objectives:

1. Identify the differences, advantages, and disadvantages of stool culture and PCR diagnostics.

2. Demonstrate how to effectively transition from culture to PCR.

3. Identify how can laboratories increase their readiness to respond to outbreaks.

RNA viruses use a variety of interactions with host proteins to gain entry, to evade immune responses, to promote viral replication, and to promote viral egress and spread. These interactions with virally encoded proteins often modulate cell-intrinsic and cell-extrinsic host signaling pathways. Our recent genome-wide ‘omics studies identified a number of host factors that are important for RNA viral infections, including an LDL family receptor that promotes vector-borne viral infections. Our results coupled with emerging data from the field reveal that multiple bunyavirus infections are facilitated by LDL related protein 1 (Lrp1) and its family members. Following our initial observation, we have pursued biochemical and structural studies to define how Lrp1 interaction with viral factors contributes to infection in vitro and in vivo. Deletion of Lrp1 in cells result in significant reduction in infection. In mice, tissue specific deletion of Lrp1 prevented hepatic infection, but did not prevent death, suggesting a role for non-hepatic Lrp1 in systemic dissemination, including neuroinvasion. The impact of LDL related receptor use by bunyaviruses will be discussed in the context of tropism and dissemination. Our findings will be further compared to emerging data that support the potential use of other LDL family proteins by a diverse group of viruses. Collectively, these studies provide new insights into vector-borne viral infections and provide previously unrecognized opportunities to define therapeutic targets.

Learning Objectives:

1. Demonstrate how molecular mechanisms control viral entry.

2. Demonstrate how biochemical and cell biological tools provide insights into host-pathogen interactions.

3. Define pros and cons of a reductionist approach to work with pathogens and how insights from such can provide potential clinical insights.

Borrelia burgdorferi, the causative agent of Lyme disease, cycles between an Ixodes spp. vector and a vertebrate reservoir host, typically small rodents. Humans become infected when they intrude upon this enzootic cycle, providing a blood meal for an infected tick. To sustain its dual-host lifestyle, B. burgdorferi employs elegant regulatory mechanisms to remodel its transcriptome in response to tick- and mammalian host-derived signals, a process collectively referred to as ‘host-adaptation’. The majority of differentially-expressed genes involved host-adaptation by Lyme disease spirochetes are controlled by two regulatory pathways. The first centers on the Hk1/Rrp1 two component system, which acts through c-di-GMP and is required for spirochete survival during the tick feeding. The second pathway, BosR/Rrp2/RpoN/RpoS, where RpoS is the effector sigma factor, is activated in ticks and upregulates genes required for tick transmission and mammalian infection. Notably, RpoS also functions, either directly or indirectly, to repress the expression of tick-phase borrelial genes following transmission, leading to its designation as the ‘gatekeeper’. Using a novel RNAseq enrichment technique, we compared the transcriptomes of wild-type and rpoS mutant strains in ticks and mammals. These analyses established that the contours of differentially expressed genes differ dramatically during the tick and mammalian host phases of the enzootic cycle and that RpoS-dependent gene regulation is modulated by the presence/absence of c-di-GMP. Unexpectedly, we also found that BosR, a FUR family regulator, and the c-di-GMP effector PlzA reciprocally regulate RpoS’s gatekeeper function in mammals and ticks, respectively.

Learning Objectives:

1. Demonstrate an understanding of the enzootic cycle that maintains Borrelia burgdorferi, the causative agent of Lyme disease, in nature.

2. Demonstrate a basic understanding of how Borrelia burgdorferi senses and responds to environmental signals encountered in ticks and mammals.

3. Summarize how the two major transcriptional regulatory pathways encoded by Borrelia burgdorferi coordinate the expression of genes required for tick-to-mammal transmission and persistence in mammals, including humans.

Helicobacter pylori is the primary cause of 78% of gastric cancer cases, providing an opportunity to prevent cancer by controlling a single bacterial pathogen within the complex gastric microbiota. Worldwide, over 750,000 deaths are due to gastric cancer annually, and increasing H. pylori antibiotic resistance threatens control strategies. We developed highly selective antimicrobial agents against H. pylori by fusing an H. pylori-binding guide peptide (MM1) to broad spectrum antimicrobial peptides. The common dairy probiotic Lactococcus lactis was then engineered to secrete these guided antimicrobial peptides (gAMPs). When co-cultured in vitro with H. pylori, the gAMP probiotics were at least 10-fold less toxic against off-target bacteria while remaining fully toxic against the targeted H. pylori. The MM1 guide was shown to specifically bind to H. pylori and not off-target bacteria using a guide-GFP fusion protein and flow cytometry. These highly selective gAMP probiotics were then tested by oral gavage in mice infected with H. pylori. As a therapy, the probiotics outperformed antibiotic treatment, effectively eliminating H. pylori in just five days, and also protected mice from challenge infection as a prophylactic. As expected, the gAMP probiotics were as toxic against H. pylori as the unguided AMP probiotics, though both guided and unguided AMPs were effective in restoring the microbiome diversity, indicating that simply alleviating the dysbiosis of H. pylori infection was the major factor in diversity restoration. Given the commercial success of the engineered probiotic from Zbiotics, there may commercial space for highly selective yet inexpensive antimicrobials such as the one presented here.

Learning Objectives:

1. Evaluate the potential of the newly emerging technology of probiotics engineered to deliver therapeutic peptides for different applications. For which applications would this technology be inappropriate?

2. Determine the risks associated with continued antibiotic use versus the use of probiotics engineered to deliver antimicrobial peptides specifically targeting bacterial pathogens.

3. Evaluate the potential for (or currently actual) commercial availability of engineered probiotics.

Antimicrobial resistance is an important and pressing challenge for global human health. Several obstacles in understanding, diagnosing, and treating antimicrobial resistance limit our ability to address this growing challenge in the clinic. Here we discuss recent innovations in machine learning that are poised to address each of these obstacles.

Learning Objectives:

1. Recognize mechanisms underlying antimicrobial efficacy and resistance.

2. Identify critical obstacles in addressing the problem of antimicrobial resistance.

3. Define cutting-edge machine learning approaches to diagnosing and treating resistance.

Globally, women are disproportionately affected by sexually transmitted infections (STI) including HIV. The immune system of the female reproductive tract (FRT) balances the unique role of providing protection against pathogens while ensuring successful reproduction to occur. FRT immunity is multi-layered and intricately regulated by sex hormones estrogen and progesterone. The vaginal microbiome plays a major role in the protection of the FRT and dysbiosis of the microbiome can lead to bacterial vaginosis, which makes women susceptible to HIV/STI. The objective of this presentation is to provide an overview of the innate immune responses of the human FRT and discuss how microbial dysbiosis can compromise women’s health.

Learning Objectives:

1. Demonstrate understanding of the basic concepts of innate immunity in the human female reproductive tract.

2. Explain how vaginal microbial dysbiosis compromises women’s health.

3. Summarize the mechanisms of how vaginal microbiome dysbiosis can impact the risk of HIV acquisition.

Human respiratory syncytial virus (RSV) remains a significant public health concern, particularly for vulnerable populations such as infants, young children, and immunocompromised individuals. In this webinar we focus on the crucial role of RSV antigens and antibodies in research, and the development of diagnostics, therapeutics, and vaccines against RSV. We will provide a comprehensive overview of RSV, highlighting its epidemiology, clinical manifestations, and associated complications. Through this talk, we aim to showcase the power of recombinant antigens and antibodies in enhancing RSV detection, characterization, and understanding of viral pathogenesis.

Learning Objectives:

1. Outline the human respiratory syncytial virus (RSV) and its impact on public health.

2. Identify RSV’s major antigens such as the fusion (F) protein, attachment (G) protein, and matrix (M) protein and their functions.

3. Discuss biomedical research on RSV and the crucial role of recombinant antigens and antibodies.

4. Discuss RSV vaccine development: challenges and future directions.

Human skin is characterized by a limited number of phyla including, Actinomycetota, Bacillota and Pseudomonadota. In particular, Staphylococcus (Bacillota) and Corynebacterium (Actinomycetota) are dominant genera present on the skin. While clinically relevant members of these taxa are well characterized (e.g., S. aureus), some coagulase-negative Staphylococci and non-diphtheria Corynebacteria remain under-sequenced. We analyzed 16S rRNA V1-V3 marker data from 23 healthy volunteers to identify species from these two genera that were both abundant and prevalent on healthy human skin. S. capitis, S. epidermidis and S. hominis were the dominant Staphylococcus species on skin, found on 100% of subjects. We sequenced 126 genomes from these species to fill out the taxonomic tree and build a genus-wide pangenome. The genus-core consisted of 1660 genes (21%) which included pathways with a predicted functions in skin colonization. The remaining 79% of genes in the pangenome catalog were present in only a subset of genomes and included pathways involved in amino acid and cofactor metabolism. 16S rRNA gene analysis also identified Corynebacterium tuberculostearicum at 94% of body sites and 100% of individuals. We sequenced a collection of 23 Corynebacterium genomes that, when placed in the context of a whole genome phylogenetic tree, support the hypothesis that C. tuberculostearicum is a species complex rather than a single species. In addition, we propose that four of our strains belong to a new species with a strong niche-specificity for sites on the feet. The expanded genome collection, when compared to existing public references, facilitated the mapping of 24% more C. tuberculostearicum species complex metagenomic reads across body sites and individuals. In summary, genome sequencing of four prevalent skin-associated species contributes to a more complete catalog of skin bacteria and improves our understanding of microbial diversity on the skin. 

Learning Objectives: 

1. Describe key features and taxa of the skin microbiome.

2. Discuss the functional diversity of coagulase-negative Staphylococcus on the skin.

3. Recognize genomic and pangenomic features of specialization on the skin.

Emerging viruses like SARS, SARS-CoV-2, MERS-CoV, Hendra, Nipah, West Nile, sin nombre, LuJo, MERS, Powassan, dengue, chikungunya, zika, Ebola, and Marburg pose a growing threat to public health. Rapid and earlier discovery of these viruses before/upon their entry into the human population could have facilitated rapid identification, blood supply protection, prevention of human-to-human transmission, containment, and targeted drug/vaccine design to curtail disease spread. The weight of emerging infectious disease burden is exacerbated by endemic viral and bacterial infections, as well as the challenge of antimicrobial resistance (AMR). Unveiling and characterizing new viruses in humans and wildlife, including bats, rodents, live-stock and non-human primates, especially viruses with zoonotic potential are essential for future pandemic prevention. Our understanding of viral diversity, distribution, and circulation is still limited, thus finding any novel and an unknown virus is difficult and require sensitive highthroughput discovery tools.

We pioneered state-of-the-art; 1] molecular detection tools: VirCapSeq-VERT (for viruses) and BacCapSeq (for bacteria and AMR), both exhibit ~3-4 logs increased sensitivity than standard unbiased highthroughput sequencing, and 2] highthroughput serology: NGSeroDx, that enables indirect detection by identifying intricate immune responses against microbial infections. These technologies have the potential to revolutionize clinical microbiology, infectious disease research, and public health efforts by contributing to enhanced preparedness for health emergencies and identification of novel infectious agents. Operational simplicity and rapid turnaround make them valuable tools by advancing pathogen discovery, rapid detection, and characterization of all known and novel viral and bacterial infections in less than 24 hours. We can also apply these tools for rapid and efficient clinical diagnosis for timely clinical interventions. Recently VirCapSeq-VERT obtained NYSDOH-CLEP approval for clinical testing, and other methods are also in process of obtaining regulatory approvals for clinical uses.  We also foster wider use of our tools by comprehensive global collaboration through the Global Alliance for Preventing Pandemics (GAPP) program.

Learning Objects:

1. Evaluate cutting-edge molecular and serological diagnostic technologies, VirCapSeq-VERT, BacCapSeq, and NGSeroDx for the simultaneous detection of viral and bacterial infections with high sensitivity and specificity.

2. Recognize sustainable global infrastructure for microbial discovery, surveillance, diagnostics, and response through capacity building and the pursuit of research questions that focus on the emerging infections, zoonoses, potential pathogenesis of unexplained illnesses and cross-species transmission of infectious diseases.

3. Discover a secure cloud-based system for data processing and analysis, enabling seamless communication and sharing of sequencing data and expertise within the network and with stakeholders and public health agencies worldwide. This system will promote situational awareness, track pathogen evolution, and aid in identifying sites for sample collection and clinical trials.

The tumor-associated microbiota is an inherent component of the tumor microenvironment across various human cancer types1. Although members of tumor-associated microbiomes can be identified through 16S rRNA analysis, physical access to bacterial isolates facilitates functional and mechanistic studies to determine the role of these bacterial species in cancer initiation, progression, and patient response to treatment. Here, through complimentary application of large-scale culturing techniques and bacterial single-cell whole genome sequencing approaches, we isolated three novel bacterial species across four tumor tissue samples from patients with colorectal cancer, including a novel Fusobacterium species2. Utilizing PacBio Single Molecule Real Time (SMRT) sequencing we obtained complete genomes for all three novel bacterial species, which facilitated comparative genomics to identify the nearest species neighbors and bioinformatic analyses to distinguish genetic factors that are uniquely present in these tumor isolates. These analyses will inform future mechanistic studies to understand the capabilities and roles of these novel bacterial species.

Learning Objectives:

1. Describe the advantages and disadvantages of various techniques and technologies to identify and culture bacterial species from a tissue-associated microbial community.

2. Explain why physical access to bacterial isolates can be a powerful advantage to microbiologists.

3. Discuss at least two approaches by which the novelty of a bacterial species can be confirmed.

The arenaviruses are an important group of pathogens that includes several agents of severe human disease, with symptoms that include hemorrhagic fever and neurological complications; however, closely related family members are often apathogenic. The basis for this difference remains poorly understood, although regulation of host cell responses appears to play an important role. Our work has revealed differences in the ability of highly pathogenic arenaviruses (i.e. Junín virus) and their closely-related apathogenic relatives (i.e. Tacaribe virus) to regulate the induction of apoptosis during infection, and this has led us to study both the mechanism involved and its consequences for virus biology. In addition to identifying key proapoptotic factors responsible for triggering apoptosis in response to infection (i.e. p53, Puma, Noxa), we have recently demonstrated the upregulation of stress-activated protein kinases that appear to contribute to this process (i.e. p38, JNK), and identified the upstream viral and host interaction partners responsible for activation of this cascade. Interestingly, these studies revealed that activation of kinases during infection appears to be crucial for virus infection, while the late-stages of apoptotic cell death itself are not. Supporting this, we have also shown that the pathogenic Junín virus actively suppresses caspases activation by sacrificing a subset of its nucleoprotein as a decoy substrate for caspase cleavage - a process that appears to play a role in the regulation of the antiviral response to infection. This is consistent with our work in primary targets cells where we see dramatic differences in the regulation of innate immunity between these viruses, and also with differences in outcome in animal models (as well as in humans). Taken together these studies advance out understanding of the virus-host interface and its role in disease outcome.

Learning Objectives:

1. Describe the two key pathways responsible for the regulation of apoptotic cell death

2. Summarize the changes in the host cell that trigger apoptosis in response to arenavirus infection

3. Explain how differences in the apoptosis regulatory mechanisms of arenaviruses contribute to different disease outcomes

Adjuvant discovery is largely devoted toward the development of vaccines meant to elicit prophylactic humoral immunity.  While useful against infectious diseases, this mode of adaptive immunity is generally insufficient for promoting therapeutic immunity against chronic diseases and cancer. Therapeutic intervention requires the generation of robust cellular immunity, a challenge that requires a change in our approach to the use of adjuvants and our approach to adjuvants and vaccination.  This talk with address the need for T cells in successful therapeutic intervention in cancer, the capacity of vaccines to generate the frequency of T cells needed, and changes to vaccine adjuvant design and delivery that could be implemented to augment vaccine-elicited cellular immunity.

Learning objectives:

1. Demonstrate understand for the immunological demands for eliciting cellular immunity appropriate for therapeutic intervention.

2. Recognize current approaches to adjuvant-elicited cellular immunity.

3. Identify biological and practical considerations for improving the use of adjuvants in therapeutic intervention.

Intestinal epithelial cells lining the surface of our gastro-intestinal tract form a tight monolayer which serves as the primary barrier separating us from the luminal content of the gut. The lumen of the gut is home to a very complex commensal bacterial microbiota but also contains potential enteric viral (e.g. Rotavirus, Norovirus), bacterial (e.g Salmonella) and eukaryotic unicellular pathogens (e.g. Cryptosporidium). An important biochemical feature of our gastro-intestinal tract is the near absence of oxygen in the lumen of the gut known as the hypoxia environment. While it well established that hypoxia is critical to maintain a healthy microbiota, how the low oxygen environment impacts the response of intestinal epithelial cells to enteric pathogens remains unexplored. Here, we employed both intestinal cell lines and human intestinal organoids to monitor how hypoxia impacts the intrinsic immune response generated by intestinal epithelial cells upon enteric virus infection. We found that hypoxia decreased the induction of both type I and III interferons which are key cytokines controlling virus infection, replication, and spread. We could show that under low oxygen conditions, intestinal epithelial cells are more susceptible to viral infection. Under hypoxia, enteric virus replication is significantly increased, and cells generate more de-novo infectious progeny virus particles compared to intestinal epithelial cells grown in normal levels of oxygen (normoxia). Interestingly, we observed the same inhibition of interferon expression in non-infected cells showing that hypoxia dampens the basal immune response of cells directly impacting their steady state susceptibility to virus infection. We identified the mechanisms leading to this hypoxia-mediated inhibition of immune response and impairing the activity or expression of the key proteins regulating these processes restore the proper immune response and control of enteric virus infection by intestinal epithelial cells under hypoxia. Importantly, we could show that this hypoxia-mediated inhibition of immune response is not limited to enteric viruses but also applies to enteric bacterial pathogens (Salmonella) and eukaryotic unicellular enteric pathogens (Cryptosporidium).

Our results demonstrate that hypoxia plays a key role in regulating the response of intestinal epithelial cells to enteric pathogens. While this hypoxia-mediated down regulation of immune response appears at first to be bad for the host to as it may favor enteric pathogen infection, we suggest that it participates in maintaining gut homeostasis. Indeed, oxygen levels vary along the crypt/villi structures formed by the epithelium with the tip of the villi being located under hypoxia while the crypts structures are located under normoxic conditions of oxygen. As such, we propose that along the crypt/villi structure a gradient of immune response is established to allow efficient protection of the stem cells located in the crypts (normoxia) and to blunt the response against the microbiome at the tip of the villi.

Learning objectives:

1. Define the intrinsic innate immune response generate by intestinal epithelial cells to fight enteric viruses.

2. Explain the difference between type I and type III interferons.

3. Discuss how low oxygen levels impair intrinsic innate immune response and how this, in turn, favors pathogen infection.

The COVID-19 pandemic is a dramatic reminder of the problems that viral zoonoses can cause worldwide. The rapid development of vaccines and antivirals against SARS-CoV-2 was only possible because the structural and functional biology of other coronaviruses was already known. This knowledge is often lacking for other emerging viruses. An illustration is the supergroup of arthropod-borne viruses (arboviruses), whose spread is accelerated by global warming and human activities. Yet these viruses have a high potential for emergence in humans and livestock. Ideally, preventing the spread of arboviruses and other zoonotic viruses requires approaches that target early stages of transmission and virus-host cell interactions, which is precisely the focus of this lecture. First, I will introduce arboviruses and explain why it is biologically relevant to study these viruses. We will then briefly discuss the complex life cycle of arboviruses in both arthropods and mammals, which vary significantly in their molecular and cellular biology. I will then provide general principles on the transmission of these viruses to human and mammalian hosts by their arthropod vectors. Finally, we will discuss in detail how this vector-host transition is used by arboviruses at the molecular and cellular levels to promote their transmission and spread.

Learning Objectives:

1. Describe the biological relevance of studying arboviruses, including their potential for spillover into human and livestock populations.

2. Explain the complex life cycles of arboviruses within arthropod and mammalian hosts, highlighting the significant variations in molecular and cellular biology involved.

3. Analyze and discuss the molecular and cellular mechanisms employed by arboviruses during the vector-host transition, specifically focusing on their strategies for transmission and spread.

The immune system evolved to protect us against pathogen invasion and to maintain tissue homeostasis. Fundamental for these functions are the interferons (IFNs), a group of cytokines that belongs to three major families: IFN-I, IFN-II, and IFN-III. The amount of interferons produced during an immune response is well known to determine the balance between anti-microbial functions and interferon-mediated diseases, known as interferonopathies. Here, we will discuss how, beside the amount, the type of IFN produced, as well as the location and timing of their production, affect the immune response in the respiratory tract during a viral infection. Furthermore, we will present data that demonstrate how the production of IFNs in a specific anatomical location can be exploited to design new adjuvants that increase the efficacy of vaccines against life-threatening virus infections, such as SARS-CoV-2, or Influenza A Virus.

Learning Objectives:

1. Discuss the advantages and disadvantages of the responses induced by interferons during COVID-19.

2. Discuss how the physical properties of microbial ligands affect the immune response in the lymph node.

3. Discuss how the immune system balance anti-microbial and tissue damaging responses.

A significant increase in agricultural production is needed to meet the demand for food to feed the expected ~10 billion people by 2050. This increased agricultural output will also require sustainable and environmentally friendly practices including reducing or eliminating reliance on chemical fertilizers, which are also source of environmental pollution. One of the potential solutions to this global challenge is to inoculate plants with beneficial microorganisms that are able to promote plant growth by a variety of mechanisms. Plant growth promoting rhizobacteria or PGPR are a diverse group of beneficial soil bacteria that are currently used as bio-inoculants and/or bio-fertilizers when inoculated to crops. A prerequisite to promoting plant growth is the ability to colonize the root surfaces. The root surfaces and the zone around the roots under the influence of plant secretion, a.k.a. the rhizosphere, is a spatially and chemically heterogenous environment and bacteria must be able to successfully navigate in the rhizosphere to colonize root surfaces. Bacterial motility and chemotaxis have been repeatedly shown in experiments to be required for a successful colonization of plant root surfaces by rhizosphere bacteria, including PGPR. The chemotaxis function is also enriched in soil and root bacterial metagenomes compared to the human gut or the oceans metagenomes. The presentation will compare and contrast recent approaches and improved tools to study bacterial chemotaxis in real time in the rhizosphere using model PGPR. The insight gained from the recent studies regarding the role of chemotaxis and root surface colonization in some of the PGPR will also be discussed.

Learning Objectives: 

1. Describe roles that plant growth promoting rhizobacteria (PGPR) have in sustainable agricultural practices.

2. Explain the role of bacterial chemotaxis in navigating the rhizosphere and in plant root surface colonization.

3. Cite examples of spatial and temporal gradient chemotaxis assays.

4. Compare and contrast the sensitivity of the different assays for studying bacterial chemotaxis in PGPR.

5. Cite examples of evidence for chemotaxis in supporting plant root colonization in PGPR.

The encapsulated fungus Cryptococcus neoformans is the most common cause of fungal meningitis, with the highest rate of cryptococcosis found in AIDS patients. Despite antifungal treatment, cryptococcal meningitis is known for its high morbidity and mortality rates due to its difficult eradication from the brain. C. neoformans’ capsule contributes directly to its pathogenesis; specifically, its main component, glucuronoxylomannan (GXM), has been associated with disruption of the blood-brain barrier (BBB) and invasion of the brain. Microglia are the main form of active immune defense in the central nervous system (CNS). These cells are critical for combating CNS-invading microbes, including C. neoformans, but the specific function(s) of microglia required to counteract GXM’s BBB damage and C. neoformans invasion is/are poorly understood. Identification of the mechanisms by which C. neoformans GXM alters the BBB integrity and microglia cell functions will provide novel insights into the neurotropism of this deadly infection and may offer new therapeutic opportunities and preventive measures for combating cerebral cryptococcosis, a disease that kills ~200,000 AIDS patients annually around the world.

Learning objectives:

1. Outline the impact of fungal brain infections on susceptible hosts.

2. Define the virulence factors of Cryptococcus neoformans.

3. Describe the effects of C. neoformans capsule on microglial responses and function.

Malaria is a life-threatening disease that is caused by unicellular eukaryotic parasites of the genus Plasmodium, with P. falciparum being responsible for the most severe form of human malaria. In the clinically relevant blood stage of infection, the parasite proliferates inside erythrocytes via an unusual cell cycle called schizogony. A hallmark of schizogony is the presence of multinucleated cells where the nuclei divide asynchronously despite residing in a common cytoplasm. To investigate the mechanistic basis of schizogony and its molecular determinants, we combine long-term live-cell imaging, genetic, and proteomic approaches as well as mathematical modelling. Our recent work determined how DNA replication and nuclear division are integrated during schizogony and we quantified the dynamics of nuclear multiplication throughout schizogony. This indicates that asynchronous nuclear cycles in the multinucleated schizont facilitate rapid P. falciparum proliferation. We also provide evidence that in P. falciparum early mitotic events a linked to the onset of S-phase, which may compensate for the absence of canonical cell cycle checkpoints. Together, our work on P. falciparum proliferation can highlight targets for chemotherapeutic intervention to curb malaria.

Learning Objectives: 

1. Define the unusual mode of proliferation of the malaria-causing parasite Plasmodium falciparum.

2. Discuss the advantages of P. falciparum’s unusual mode of proliferation.

3. Associate molecular determinants with specific features of P. falciparum proliferation.