The internet-based fungal pathogen database: a proposed model

ABSTRACT A better understanding of the phenotypic and genetic diversity of significant agricultural pathogens and how their populations change in the field is critical for designing successful, long-term disease management strategies. Although efforts to determine the genetic diversity of plant pathogens have substantially increased in recent years, mainly due to the availability of various molecular tools, complementary efforts to archive and integrate the resulting data have been very limited. As a consequence, it is often difficult to compare the available data from various laboratories because the data have been generated by diverse tools, often preventing any direct comparisons, and are saved in a format that is unsuitable for comparative studies. The establishment of an internet-based database that cross-links the digitized genotypic and phenotypic information of individual pathogens at both the species and population levels may allow us to effectively address these problems by coordinating the generation of data and its subsequent archiving. We discuss the needs, benefits, and potential structure of such a database.     

Cerebrospinal angiostrongyliasis in five captive tamarins (Sanguinus spp)

Four cotton-top tamarins ( Sanguinus oedipus oedipus ) and one emperor tamarin ( S imperator subgrisescens ) housed in a zoo became depressed, anorexic, paraparetic and eventually paralysed. The animals died within 5 days to 18 months of the appearance of clinical signs. Histological examination showed nonsuppurative and eosinophilic meningoencephalitis, and metastrongyle nematode larvae were found within subarachnoid spaces of all animals and within the spinal cord of one. Intact larvae with features consistent with Angiostrongylus cantonensis were recovered from the brain of one animal. This parasite is the classical cause of eosinophilic meningoencephalitis in many parts of the world and the diagnosis can be strongly suspected on clinical grounds. In endemic areas like south-east Queensland, protection of captive animals against infection with A cantonensisi s a difficult balance between providing a stimulating, natural setting and eliminating potentially infectious definitive, intermediate and paratenic hosts… This is the first report of cerebrospinal angiostrongyliasis in tamarins and nonhuman primates in Australia.     

A review of the known unknowns in the early stages of septoria tritici blotch disease of wheat

Septoria tritici blotch (STB) disease of wheat is caused by the fungal pathogen Zymoseptoria tritici. It is the most important foliar disease of wheat in western Europe and affects wheat cultivation worldwide. The combination of intensive fungicide usage, a polycyclic asexual life cycle and an active sexual cycle has led to the emergence of fungal strains resistant/tolerant to all the major classes of fungicides used in its control. The hallmark of this disease is a long, symptomless latent phase that precedes the onset of visible symptoms. Understanding the processes that occur during the symptomless phase of infection is paramount in developing alternative strategies for disease control; however, large gaps in our knowledge of the disease remain. The known unknowns of the latent stage of infection can be summarized in three questions. Does the fungus initiate or manipulate host defences to trigger programmed cell death in order to facilitate nutrient acquisition or is the host acting exclusively? Does the fungus feed during both the latent phase and the necrotrophic phase like a true hemibiotroph? Does the long latent phase serve a beneficial function for the fungus or is it simply an artefact of evolution? This review aims to distil observations made during studies that have directly or indirectly contributed to answering these questions and points towards their most likely answers.     

Factors associated with Echinococcus multilocularis infection in coyotes in southern Ontario

Echinococcus multilocularis was recently reported in wild canids across southern Ontario, a newly recognized endemic area in Canada. In such areas, a comprehensive understanding of factors associated with infection in definitive hosts (wild canids) is critical for mitigating risk of transmission to humans. However, little is known about the transmission dynamics of the parasite in definitive hosts for this region. A study was therefore carried out to investigate the association of host‐level (sex, body condition), environmental (southern Ontario region, land cover), temporal (season, hunting season, calendar year) and extraneous factors (submitter type) with E. multilocularis infection in coyotes in southern Ontario. Between November 2015 and March 2017, 416 coyotes were collected from across the region as part of a study that investigated the prevalence and distribution of the parasite in wild canids; approximately 24% of coyotes were positive for E. multilocularis. Associations between infection and factors of interest were assessed via a mixed‐effects logistic regression model with a random intercept for submitter to account for clustering. Coyotes with poor body condition were at greater odds of E. multilocularis infection than those in good condition (odds ratio [OR] 2.14; 95% CI: 1.08–4.26; p = .030). A negative association was observed between infection in coyotes and the proportion of natural land in a coyote's estimated home range (OR: 0.67; 95% CI: 0.52–0.85; p = .001). Coyotes from the western region of southern Ontario had lower odds of infection compared to coyotes from the central region (OR: 0.26; 95% CI: 0.12–0.55; p < .001). These results can be used to help guide future public health prevention strategies for human alveolar echinococcosis.     

Genetic analysis of digestive physiology using fluorescent phospholipid reporters

Zebrafish are a valuable model for mammalian lipid metabolism; larvae process lipids similarly through the intestine and hepatobiliary system and respond to drugs that block cholesterol synthesis in humans. After ingestion of fluorescently quenched phospholipids, endogenous lipase activity and rapid transport of cleavage products results in intense gall bladder fluorescence. Genetic screening identifies zebrafish mutants, such as fat free, that show normal digestive organ morphology but severely reduced phospholipid and cholesterol processing. Thus, fluorescent lipids provide a sensitive readout of lipid metabolism and are a powerful tool for identifying genes that mediate vertebrate digestive physiology.     

The distribution of active force generators controls mitotic spindle position

During unequal cell divisions a mitotic spindle is eccentrically positioned before cell cleavage. To determine the basis of the net force imbalance that causes spindle displacement in one-cell Caenorhabditis elegans embryos, we fragmented centrosomes with an ultraviolet laser. Analysis of the mean and variance of fragment speeds suggests that the force imbalance is due to a larger number of force generators pulling on astral microtubules of the posterior aster relative to the anterior aster. Moreover, activation of heterotrimeric guanine nucleotide- binding protein (Gprotein) alpha subunits is required to generate these astral forces.