Fungal Pathogens in Grasslands

Grasslands are major primary producers and function as major components of important watersheds. Although a concise definition of grasslands cannot be given using a physiognomic or structural approach, grasslands can be described as vegetation communities experiencing periodical droughts and with canopies dominated by grasses and grass-like plants. Grasslands have a cosmopolitan distribution except for the Antarctic region. Fungal interactions with grasses can be pathogenic or symbiotic. Herbivorous mammals, insects, other grassland animals, and fungal pathogens are known to play important roles in maintaining the biomass and biodiversity of grasslands. Although most pathogenicity studies on the members of Poaceae have been focused on economically important crops, the plant-fungal pathogenic interactions involved can extend to the full range of ecological circumstances that exist in nature. Hence, it is important to delineate the fungal pathogen communities and their interactions in man-made monoculture systems and highly diverse natural ecosystems. A better understanding of the key fungal players can be achieved by combining modern techniques such as next-generation sequencing (NGS) together with studies involving classic phytopathology, taxonomy, and phylogeny. It is of utmost importance to develop experimental designs that account for the ecological complexity of the relationships between grasses and fungi, both above and below ground. In grasslands, loss in species diversity increases interactions such as herbivory, mutualism, predation or infectious disease transmission. Host species density and the presence of heterospecific host species, also affect the disease dynamics in grasslands. Many studies have shown that lower species diversity increases the severity as well as the transmission rate of fungal diseases. Moreover, communities that were once highly diverse but have experienced decreased species richness and dominancy have also shown higher pathogenicity load due to the relaxed competition, although this effect is lower in natural communities. This review addresses the taxonomy, phylogeny, and ecology of grassland fungal pathogens and their interactions in grassland ecosystems.

Evaluation measure for group-based record linkage

INTRODUCTION

The robustness of record linkage evaluation measures is of high importance since linkage techniques are assessed based on these. However, minimal research has been conducted to evaluate the suitability of existing evaluation measures in the context of linking groups of records. Linkage quality is generally evaluated based on traditional measures such as precision and recall. As we show, these traditional evaluation measures are not suitable for evaluating groups of linked records because they evaluate the quality of individual record pairs rather than the quality of records grouped into clusters.

OBJECTIVES

We set out to highlight the shortcomings of traditional evaluation measures and then propose a novel method to evaluate clustering quality in the context of group-based record linkage.

METHODS

The proposed linkage evaluation method assesses how well individual records have been allocated into predicted groups/clusters with respect to ground-truth data. We first identify the best representative predicted cluster for each ground-truth cluster and, based on the resulting mapping, each record in a ground-truth cluster is assigned to one of seven categories. These categories reflect how well the linkage technique assigned records into groups.

RESULTS

We empirically evaluated our proposed method using real-world data and showed that it better reflects the quality of clusters generated by three group-based record linkage techniques. We also showed that traditional measures such as precision and recall can produce ambiguous results whereas our method does not.

CONCLUSIONS

The proposed evaluation method provides unambiguous results regarding the assessed group-based record linkage approaches. The method comprises of seven categories which reflect how each record was predicted, providing more detailed information about the quality of the linkage result. This will help to make better-informed decisions about which linkage technique is best suited for a given linkage application.

Cytotoxic effects of ergone, a compound isolated from Fulviformes fastuosus

BACKGROUND

Mushrooms inspired the cuisines of many cultures and conventional medicaments for cancer. However, a substantial number of mushroom species are yet unexplored, possessing an unknown chemical, biological and pharmacological profiles. Fulviformes fastuosus is a terrestrial mushroom, which is commonly found in Sri Lankan woodlands. The current study was aimed at isolation and characterization of a potent cytotoxic compound from F. fastuosus and investigating the apoptotic effect induced by the active principle against cancer and normal cell lines.

METHODS

Bioactivity guided isolation of active principles from the methanol extract of F. fastuosus was performed by a rapid extraction and isolation method using different chromatographic techniques. Potential cytotoxic compound was identified using one and two dimensional nuclear magnetic resonance spectroscopy and mass spectrometry. Isolated compound was screened for in vitro cytotoxicity against Hepatocellular carcinoma (HepG-2), Muscle rhabdomyosarcoma (RD) and Rat Wistar liver normal (CC-1) cell lines using 3 4, 5-(dimethylthiazol-2-yl) 2-5-diphenyl tetrazolium bromide (MTT) cell viability assay. Apoptotic features of cells were observed via microscopic examination and ethidium bromide/acridine orange fluorescent staining.

RESULTS

The interpretation of spectral data resulted in the identification of the chemical structure as ergosta-4,6,8 (14),22-tetraen-3-one (ergone). Ergone exhibited promising cytotoxic properties against RD cells with less cytotoxicity effect on CC-1 cells. In addition, ergone also possesses a strong cytotoxic effect against HepG-2 cells showing low toxic level for CC-1 cells. Apoptotic features of treated cells were detected via morphological characterization and ethidium bromide/acridine orange staining.

CONCLUSION

The present study elaborates the isolation of a potent cytotoxic compound; ergone, from F. fastuosus via a rapid and efficient isolation method. Importantly, ergone has exhibited greater cytotoxic activity against RD cells with high selectivity index compared to cytotoxicity against HepG-2 cells. Ergone can be used in the development of therapeutic strategies for curbing rhabdomyosarcoma.