Biology Of Pathogen Research Articles

HISTORY OF MYCOLOGICAL RESEARCH AT ODESA (NOVOROSSIA) UNIVERSITY (1865–1890)

Introduction. The development of mycological research in the south of Ukraine in the mid-nineteenth century was caused by a number of factors: the emergence of mycology as a scientific field, the growth of the population, for which the medical aspects of studying fungi causing dangerous diseases of humans and animals were relevant; active development of agriculture, which was significantly damaged by fungal diseases of cultivated plants. With the opening of Novorossiysk University, its biologists began to pay attention to these problems. There are only fragmentary facts about their research in the literature, scattered in different sources, so we also considered it necessary to present the materials we found from their personal biographies. The aim of our work was to study the history of mycological research at Odesa (Novorossiysk) University in the third quarter of the nineteenth century. Research methods. We studied the minutes of the meetings of the Academic Council of the Imperial Novorossiysk University (INU), the Novorossiysk Society of Naturalists (NNS), the Society of Agriculture of Southern Russia (SSAR), and the Odesa Branch of the Imperial Russian Society of Horticulture (OVIRTS); we studied the scientific publications of these institutions and societies; and we clarified the biographical data of little-known scientists from the documents of various institutions. In order to create a single holistic picture of the development of mycological research in the second half of the nineteenth century, the chronology of the accumulation of new knowledge in this field was studied. Main results. At the initial stage of mycological research at Odesa University (in the second half of the nineteenth century) in the south of Ukraine, the attention of scientists (M. K. Sredynskyi, I. F. Koshchuk, V. F. Khmelevskyi) was focused on the study of mycological diversity in the region. They studied (I. F. Koshchug, V. F. Khmelevskyi, I. M. Krasylshchyk) diseases of agricultural plants caused by parasitic fungi and methods of controlling them, the biology of individual pathogens of these diseases (L. S. Tsenkovskyi, Y. Y. Valts, L. A. Rishavi). For the first time in the south of Ukraine, fungi-parasites of harmful insects (bread beetle and beet weevil) were studied and the method of their reproduction and use in biological control of these insects was introduced (I. I. Mechnikov, I. M. Krasylshyk, V. I. Shmankevych, O. O. Yanovych, O. I. Pohibko and E. L. Rekalo).

Integrated Applied Clinical Pharmacology in the Advancement of Rare and Ultra-Rare Disease Therapeutics.

The introduction of safe and effective rare/ultra-rare disease treatments is a focus of many biotherapeutic enterprises. Despite this increased activity, a significant unmet need remains, and the responsibility to meet this need is augmented by enhanced genomic, biologic, medical, analytical, and informatic tools. It is recognized that the development of an effective and safe rare/ultra-rare disease therapeutic faces a number of challenges with an important role noted for clinical pharmacology. Clinical pharmacology is foundationally an integrative discipline which must be embedded in and is interdependent upon understanding the pathogenic biology, clinical presentation, disease progression, and end-point assessment of the disease under study. This manuscript presents an overview and two case examples of this integrative approach, the development of C5-targeted therapeutics for the treatment of generalized myasthenia gravis and asfotase alpha for the treatment of hypophosphatasia. The two presented case examples show the usefulness of understanding the biological drivers and clinical course of a rare disease, having relevant animal models, procuring informative natural history data, importing assessment tools from relevant alternative areas, and using integrated applied clinical pharmacology to inform target engagement, dose, and the cascade of pharmacodynamic and clinical effects that follow. Learnings from these programs include the importance of assuring cross-validation of assays throughout a development program and continued commitment to understanding the relationship among the array of Pd end points and clinical outcomes. Using an integrative approach, substantive work remains to be done to meet the unmet needs of patients with rare/ultra-rare disease.

Identification and characterization of the causal agent of powdery mildew on native salmonberry and thimbleberry plants in British Columbia

Salmonberry (Rubus spectabilis) and thimbleberry (Rubus nutkanus) are important native berry plants for Indigenous communities and restoration sites in the coastal region of British Columbia (BC). Compared to cultivated berry plants, information on the diseases impacting native berry plant species is limited. In late August 2022, powdery mildew symptoms and signs were observed on field plots of salmonberry and thimbleberry plants at the Agassiz Research and Development Centre, BC. The disease symptoms progressed until the end of September. The morphology of conidiophores and conidia when examined under a compound and scanning electron microscope showed they matched with those of Podosphaera aphanis. DNA from diseased foliage was subjected to PCR amplification with primers representing the internal transcribed spacer (ITS) region of rDNA followed by sequencing. The corresponding sequences from both hosts showed >99% similarity to P. aphanis in GenBank and grouped with several accessions of P. aphanis following phylogenetic analysis. In artificially inoculated trials conducted in the greenhouse, powdery mildew symptoms developed within 3−4 weeks post-inoculation and P. aphanis isolates from salmonberry and thimbleberry were cross-pathogenic to each host. To our knowledge, this is the first study characterizing the powdery mildew pathogen infecting salmonberry and thimbleberry and demonstrating cross-pathogenicity to both hosts. The outcomes from this study provide insight into the biology of the powdery mildew pathogen infecting native Rubus spp.

Transoceanic pathogen transfer in the age of sail and steam

In the centuries following Christopher Columbus's 1492 voyage to the Americas, transoceanic travel opened unprecedented pathways in global pathogen circulation. Yet no biological transfer is a single, discrete event. We use mathematical modeling to quantify historical risk of shipborne pathogen introduction, exploring the respective contributions of journey time, ship size, population susceptibility, transmission intensity, density dependence, and pathogen biology. We contextualize our results using port arrivals data from San Francisco, 1850 to 1852, and from a selection of historically significant voyages, 1492 to 1918. We offer numerical estimates of introduction risk across historically realistic ranges of journey time and ship population size, and show that both steam travel and shipping regimes that involved frequent, large-scale movement of people substantially increased risk of transoceanic pathogen circulation.

Integrating bacterial molecular genetics with chemical biology for renewed antibacterial drug discovery.

The application of dyes to understanding the aetiology of infection inspired antimicrobial chemotherapy and the first wave of antibacterial drugs. The second wave of antibacterial drug discovery was driven by rapid discovery of natural products, now making up 69% of current antibacterial drugs. But now with the most prevalent natural products already discovered, ∼107 new soil-dwelling bacterial species must be screened to discover one new class of natural product. Therefore, instead of a third wave of antibacterial drug discovery, there is now a discovery bottleneck. Unlike natural products which are curated by billions of years of microbial antagonism, the vast synthetic chemical space still requires artificial curation through the therapeutics science of antibacterial drugs - a systematic understanding of how small molecules interact with bacterial physiology, effect desired phenotypes, and benefit the host. Bacterial molecular genetics can elucidate pathogen biology relevant to therapeutics development, but it can also be applied directly to understanding mechanisms and liabilities of new chemical agents with new mechanisms of action. Therefore, the next phase of antibacterial drug discovery could be enabled by integrating chemical expertise with systematic dissection of bacterial infection biology. Facing the ambitious endeavour to find new molecules from nature or new-to-nature which cure bacterial infections, the capabilities furnished by modern chemical biology and molecular genetics can be applied to prospecting for chemical modulators of new targets which circumvent prevalent resistance mechanisms.

Management and breeding for rust resistance in legumes

AbstractRust diseases are a major concern in legume production worldwide causing heavy losses especially in developing countries that depend on grain legumes as staple food. Fungal species from Uromyces, Phakopsora and Puccinia genera are the main causal agents of the various legume rust diseases. They induce up to 100% yield losses on susceptible cultivars and are emerging as a substantial threat to global food security. Developing durable resistance to rust has thus become a critical breeding objective alongside efforts to improve cultural and disease management practices. This review specifically focuses on the recent advances in understanding and enhancing genetic rust resistance across diverse legume crops. Key topics covered include: (i) the diversity and host range of the rust species affecting legumes; (ii) the disease management strategies from cultural practices to chemical control; (iii) the available screening methods for identifying new sources of resistance; (iv) the genetic basis of resistance, encompassing both major resistance genes and quantitative trait loci; (v) insights into gene regulation and effector molecules leading to legume-rust interactions; and (vi) emerging genomic-assisted breeding techniques that can accelerate the development of durable rust resistance in legumes. Overall, this review highlights the progress made to date and the remaining challenges in sustainably managing rust diseases across diverse legume crops through integrated approaches spanning pathogen biology, advanced phenotyping, genetic resistance, and molecular breeding.

Transcriptome study reveals tick immune genes restrict Babesia microti infection.

A systems biology approach was employed to gain insight into tick biology and interactions between vectors and pathogens. Haemaphysalis longicornis serves as one of the primary vectors of Babesia microti, significantly impacting human and animal health. Obtaining more information about their relationship is crucial for a comprehensive understanding of tick and pathogen biology, pathogen transmission dynamics, and potential control strategies. RNA sequencing of uninfected and B. microti-infected ticks resulted in the identification of 15056 unigenes. Among these, 1051 were found to be differentially expressed, with 796 being upregulated and 255 downregulated (P < 0.05). Integrated transcriptomics datasets revealed the pivotal role of immune-related pathways, including the Toll, Janus kinase/signal transducer and activator of transcription (JAK-STAT), immunodeficiency, and RNA interference (RNAi) pathways, in response to infection. Consequently, 3 genes encoding critical transcriptional factor Dorsal, Relish, and STAT were selected for RNAi experiments. The knockdown of Dorsal, Relish, and STAT resulted in a substantial increase in Babesia infection levels compared to the respective controls. These findings significantly advanced our understanding of tick-Babesia molecular interactions and proposed novel tick antigens as potential vaccine targets against tick infestations and pathogen transmission.

The Genetics and Molecular Biology of Pathogens in Agricultural Crops

Despite advances in science and technology, agricultural yield losses due to plant pathogens and pests currently account for 30% of global production [...]

WHOLE GENOME TARGETED ENRICHMENT AND SEQUENCING OF HUMAN-INFECTING CRYPTOSPORIDIUM spp.

Cryptosporidium spp. are protozoan parasites that cause severe illness in vulnerable human populations. Obtaining pure Cryptosporidium DNA from clinical and environmental samples is challenging because the oocysts shed in contaminated feces are limited in quantity, difficult to purify efficiently, may derive from multiple species, and yield limited DNA (<40 fg/oocyst). Here, we develop and validate a set of 100,000 RNA baits (CryptoCap_100k) based on six human-infecting Cryptosporidium spp. (C. cuniculus, C. hominis, C. meleagridis, C. parvum, C. tyzzeri, and C. viatorum) to enrich Cryptosporidium spp. DNA from a wide array of samples. We demonstrate that CryptoCap_100k increases the percentage of reads mapping to target Cryptosporidium references in a wide variety of scenarios, increasing the depth and breadth of genome coverage, facilitating increased accuracy of detecting and analyzing species within a given sample, while simultaneously decreasing costs, thereby opening new opportunities to understand the complex biology of these important pathogens.

Sex Pheromone Receptor Ste2 Orchestrates Chemotropic Growth towards Pine Root Extracts in the Pitch Canker Pathogen Fusarium circinatum

In ascomycetous fungi, sexual mate recognition requires interaction of the Ste2 receptor protein produced by one partner with the α-factor peptide pheromone produced by the other partner. In some fungi, Ste2 is further needed for chemotropism towards plant roots to allow for subsequent infection and colonization. Here, we investigated whether this is also true for the pine pitch canker fungus, Fusarium circinatum, which is a devastating pathogen of pine globally. Ste2 knockout mutants were generated for two opposite mating-type isolates, after which all strains were subjected to chemotropism assays involving exudates from pine seedling roots and synthetic α-factor pheromone, as well as a range of other compounds for comparison. Our data show that Ste2 is not required for chemotropism towards any of these other compounds, but, in both wild-type strains, Ste2 deletion resulted in the loss of chemotropism towards pine root exudate. Also, irrespective of mating type, both wild-type strains displayed positive chemotropism towards α-factor pheromone, which was substantially reduced in the deletion mutants and not the complementation mutants. Taken together, these findings suggest that Ste2 likely has a key role during the infection of pine roots in production nurseries. Our study also provides a strong foundation for exploring the role of self-produced and mate-produced α-factor pheromone in the growth and overall biology of the pitch canker pathogen.

A fluorescently-tagged tick kinin neuropeptide triggers peristalsis and labels tick midgut muscles

Ticks are blood-feeding arthropods that require heme for their successful reproduction. During feeding they also acquire pathogens that are subsequently transmitted to humans, wildlife and/or livestock. Understanding the regulation of tick midgut is important for blood meal digestion, heme and nutrient absorption processes and for aspects of pathogen biology in the host. We previously demonstrated the activity of tick kinins on the cognate G protein-coupled receptor. Herein we uncovered the physiological role of the kinin receptor in the tick midgut. A fluorescently-labeled kinin peptide with the endogenous kinin 8 sequence (TMR-RK8), identical in the ticks Rhipicephalus microplus and R. sanguineus, activated and labeled the recombinant R. microplus receptor expressed in CHO-K1 cells. When applied to the live midgut the TMR-RK8 labeled the kinin receptor in muscles while the labeled peptide with the scrambled-sequence of kinin 8 (TMR-Scrambled) did not. The unlabeled kinin 8 peptide competed TMR-RK8, decreasing confocal microscopy signal intensity, indicating TMR-RK8 specificity to muscles. TMR-RK8 was active, inducing significant midgut peristalsis that was video-recorded and evaluated with video tracking software. The TMR-Scrambled peptide used as a negative control did not elicit peristalsis. The myotropic function of kinins in eliciting tick midgut peristalsis was established.

Characterization of Ssc, an N-acetylgalactosamine-containing Staphylococcus aureus surface polysaccharide.

Surface polysaccharides play crucial roles in the biology and virulence of bacterial pathogens. Staphylococcus aureus produces four major types of polysaccharides that have been well-characterized. In this study, we identified a new surface polysaccharide containing N-acetylgalactosamine (GalNAc). This marks the first report of GalNAc-containing polysaccharide in S. aureus. Our discovery lays the groundwork for further investigations into the chemical structure, surface location, and role in pathogenesis of this new polysaccharide.

The Role of Cytokinins and Abscisic Acid in the Growth, Development and Virulence of the Pathogenic Fungus Stagonospora nodorum (Berk.).

Cytokinins (CKs) and abscisic acid (ABA) play an important role in the life of both plants and pathogenic fungi. However, the role of CKs and ABA in the regulation of fungal growth, development and virulence has not been sufficiently studied. We compared the ability of two virulent isolates (SnB and Sn9MN-3A) and one avirulent isolate (Sn4VD) of the pathogenic fungus Stagonospora nodorum Berk. to synthesize three groups of hormones (CKs, ABA and auxins) and studied the effect of exogenous ABA and zeatin on the growth, sporulation and gene expression of necrotrophic effectors (NEs) and transcription factors (TFs) in them. Various isolates of S. nodorum synthesized different amounts of CKs, ABA and indoleacetic acid. Using exogenous ABA and zeatin, we proved that the effect of these hormones on the growth and sporulation of S. nodorum isolates can be opposite, depends on both the genotype of the isolate and on the concentration of the hormone and is carried out through the regulation of carbohydrate metabolism. ABA and zeatin regulated the expression of fungal TF and NE genes, but correlation analysis of these parameters showed that this effect depended on the genotype of the isolate. This study will contribute to our understanding of the role of the hormones ABA and CKs in the biology of the fungal pathogen S. nodorum.

A giant virus infecting the amoeboflagellate Naegleria

Giant viruses (Nucleocytoviricota) are significant lethality agents of various eukaryotic hosts. Although metagenomics indicates their ubiquitous distribution, available giant virus isolates are restricted to a very small number of protist and algal hosts. Here we report on the first viral isolate that replicates in the amoeboflagellate Naegleria. This genus comprises the notorious human pathogen Naegleria fowleri, the causative agent of the rare but fatal primary amoebic meningoencephalitis. We have elucidated the structure and infection cycle of this giant virus, Catovirus naegleriensis (a.k.a. Naegleriavirus, NiV), and show its unique adaptations to its Naegleria host using fluorescence in situ hybridization, electron microscopy, genomics, and proteomics. Naegleriavirus is only the fourth isolate of the highly diverse subfamily Klosneuvirinae, and like its relatives the NiV genome contains a large number of translation genes, but lacks transfer RNAs (tRNAs). NiV has acquired genes from its Naegleria host, which code for heat shock proteins and apoptosis inhibiting factors, presumably for host interactions. Notably, NiV infection was lethal to all Naegleria species tested, including the human pathogen N. fowleri. This study expands our experimental framework for investigating giant viruses and may help to better understand the basic biology of the human pathogen N. fowleri.

Ergot of cereals: Toxins, pathogens and management

AbstractErgot is a fungal disease of many plants but is perhaps most commonly associated with domesticated grasses or cereals, such as rye, wheat, barley, oat, sorghum, millet, maize and rice. Ergot is of historical significance, having been reported for several millennia, but is also of concern in modern agricultural production systems. Caused by many different species within the genus Claviceps, the fungi cause the production of sclerotia, which are typically dark in colour, in place of healthy grain. The sclerotia contain toxins that can make the grain unsafe for consumption by humans or livestock. Ergot can be managed both preharvest as well as postharvest to minimize the presence of sclerotia and their associated toxins in food and feed systems. In this review, we provide a detailed update on our current knowledge of ergot on cereals, with a focus on recent advances in our understanding of fungal toxins and their regulation, pathogen biology and disease management.

A Comprehensive Review of Sclerotinia Stem Rot in Indian Mustard (Brassica juncea)

Indian mustard (Brassica juncea), an important oilseed crop, is highly susceptible to the devastating disease called Sclerotinia stem rot, caused by the fungus Sclerotinia sclerotiorum. This review paper provides a comprehensive summary of the present understanding of the disease, encompassing its epidemiology, pathogen biology, interactions between the host and pathogen, management strategies, and the latest advancements in research. There is an urgent need for effective disease management strategies, as evident by the financial consequences of Sclerotinia stem rot on the production of Indian mustard. This review aims to comprehensively analyze research articles to enhance our understanding of the disease and expedite the development of enduring solutions to mitigate it's impacts. Rapeseed mustard is susceptible to various pathogens, including fungi, bacteria, viruses, and phytoplasma. Sclerotinia stem rot is the most severe fungal disease affecting Indian mustard. Extensive studies and development have been conducted on the occurrence of Sclerotinia rot in rapeseed mustard. This study examines these endeavors in relation to disease cycle, epidemiology, pathogen taxonomy, nature, and control. Moreover, the study aims to present a comprehensive summary of potential future goals and research methodologies concerning Sclerotinia rot in rapeseed.

Morphology, Development, and Pigment Production of Talaromyces marneffei are Diversely Modulated Under Physiologically Relevant Growth Conditions.

Talaromyces marneffei is an opportunistic pathogenic fungus that mainly affects HIV-positive individuals endemic to Southeast Asia and China. Increasing efforts have been made in the pathogenic mechanism and host interactions understanding of this pathogen in the last two decades; however, there are still no conclusions on how T. marneffei was transmitted from the donor bamboo rats to humans. A perception that the failure of fungus isolation from soil was attributed to the low salt tolerance of T. marneffei. Therefore, the effect of environmental fluctuations in fungal growth and development is fundamental for the characterization of its origin and fungal biology understanding. Herein, we characterized high osmolarity, pH, metal ions, nutrients, and oxidative stress have versatile effects on T. marneffei hyphal or yeast growth, conidia generation, and pigment production. Among these, high pH, low glucose amounts, and the inorganic nitrogen ammonium tartrate stimulated the red pigment production, whereas high osmolarity, high pH, and the inorganic nitrogen sodium nitrate could significantly accelerate the conidia generation. Specifically, zinc starvation repressed conidia generation and prevented the wrinkled yeast colony formation, indicating the function of zinc regulators in pathogenicity regulation. Since conidia are recognized as the infectious propagules, the effects characterization of different environmental factors in T. marneffei morphology in this work will not only expand the growth and pathogenic biology understanding of the fungus but also provide more clues for the T. marneffei infection transmission origin investigation.

Detecting changes in generation and serial intervals under varying pathogen biology, contact patterns and outbreak response.

The epidemiological characteristics of SARS-CoV-2 transmission have changed over the pandemic due to emergence of new variants. A decrease in the generation or serial intervals would imply a shortened transmission timescale and, hence, outbreak response measures would need to expand at a faster rate. However, there are challenges in measuring these intervals. Alongside epidemiological changes, factors like varying delays in outbreak response, social contact patterns, dependence on the growth phase of an outbreak, and effects of exposure to multiple infectors can also influence measured generation or serial intervals. To guide real-time interpretation of variant data, we simulated concurrent changes in the aforementioned factors and estimated the statistical power to detect a change in the generation and serial interval. We compared our findings to the reported decrease or lack thereof in the generation and serial intervals of different SARS-CoV-2 variants. Our study helps to clarify contradictory outbreak observations and informs the required sample sizes under certain outbreak conditions to ensure that future studies of generation and serial intervals are adequately powered.

Stable and efficient microbubble-enhanced cold plasma activation for treatment of flowing water

Cold plasma technology has received immense attention in several fields including wastewater treatment, disinfection, food processing and storage, and agriculture due to its ability to produce reactive species at low energy input. However, the scalability of generation of plasma activated water (PAW) still remains a challenge. A microbubble-enhanced cold plasma activation (MB-CPA) technology leverages small bubbles for effectively interfacing plasma discharge in a gas phase and a flow of liquid media. In this study, we develop a stable and efficient approach for the continuous production of PAW by maximizing the transfer of active species generated during plasma discharge to water flow. Novel Venturi-type microbubble generators were designed for the production of PAW by maximizing the rapid transfer of active species generated during plasma discharge in air. Key geometrical features of the tubes including the position and the opening size of the air inlet were tuned, aiming to transfer active species in a wide range of liquid flow conditions. The performance of our flow systems was evaluated by using pure water, buffered saline, and real river water containing micro-pollutants. We found that MB-CPA can effectively eliminate chemical compounds such as dye and antibiotic residues, as well as biological pathogens like Gram-positive and Gram-negative bacteria. In a cell viability assay, the technology exhibited cytotoxic effects against cancerous cells, specifically HeLa and MCF-07 cell lines. This multi-functionality underscores the versatility of MB-CPA, positioning it as a multifaceted solution for both water and wastewater treatment. Our work shows that the designed MB-CPA system represents a promising and sustainable technological advancement, offering a green alternative for the widespread activation of water in various applications.

Biogenesis, germination, and pathogenesis of Cryptococcus spores.

SUMMARYSpores are primary infectious propagules for the majority of human fungal pathogens; however, relatively little is known about their fundamental biology. One strategy to address this deficiency has been to develop the basidiospores of Cryptococcus into a model for pathogenic spore biology. Here, we provide an update on the state of the field with a comprehensive review of the data generated from the study of Cryptococcus basidiospores from their formation (sporulation) and differentiation (germination) to their roles in pathogenesis. Importantly, we provide support for the presence of basidiospores in nature, define the key characteristics that distinguish basidiospores from yeast cells, and clarify their likely roles as infectious particles. This review is intended to demonstrate the importance of basidiospores in the field of Cryptococcus research and provide a solid foundation from which researchers who wish to study sexual spores in any fungal system can launch their studies.