Biology subjects

Zasada, I.

Publications and source records attributed to Zasada, I..

5 recordsLinked to original sources

bioRxiv2026

Toxic Effects of Solanum sisymbriifolium Extracts on Meloidogyne hapla and Meloidogyne chitwoodi

Plant-parasitic nematodes (PPNs) are among the most destructive agricultural pests worldwide, causing significant economic losses across diverse cropping systems. Soil fumigation, the most common management strategy, is costly, detrimental to soil health, and increasingly restricted due to environmental and regulatory concerns. As a result, there is a critical need for alternative, sustainable approaches for PPN control. Solanum sisymbriifolium is resistant to several Meloidogyne species and represents a promising source of natural nematicidal compounds. In this study, we evaluated the effects of S. sisymbriifolium extracts on Meloidogyne chitwoodi and M. hapla, two economically important nematodes. Compounds were extracted using solvents of increasing polarity and then reconstituted in water. The water-solubilized extracts were then used in bioassays to assess their effects on nematode egg hatching, egg viability, and second-stage juvenile (J2) survival. Egg hatching and J2 viability of both Meloidogyne species were consistently affected by compounds in the 1-butanol fraction. Further characterization of these compounds may enable the development of novel, environmentally sustainable alternatives to conventional nematode management strategies.

Plant Biology↗

bioRxiv2023

Diverse Plant-Parasitic Nematodes are Selectively Killed by Oxadiazole Thioether Pro-Nematicides

Left unchecked, plant-parasitic nematodes have the potential to devastate crops globally. Highly effective but non-selective nematicides are justifiably being phased-out, leaving farmers with limited options for managing nematode infestation. Here, we report our discovery of a 1,3,4-oxadiazole thioether scaffold called Cyprocide that selectively kills diverse plant-parasitic nematodes. Cyprocide is bioactivated into a lethal reactive electrophilic metabolite by specific nematode cytochrome P450 enzymes. Because Cyprocide fails to kill non-target organisms, we infer that the targeted lethality of this pro-nematicide derives from P450 substrate selectivity. Our findings demonstrate that Cyprocide is a selective nematicidal scaffold with broad-spectrum activity that holds the potential to help safeguard our global food supply.

genetics↗

bioRxiv2022

Selective Control of Parasitic Nematodes Using Bioactivated Nematicides

Parasitic nematodes are a major threat to global food security, particularly as the world amasses 10 billion people amidst limited arable land. Most traditional nematicides have been banned due to poor nematode-selectivity, leaving farmers with inadequate controls. Here, we use the model nematode Caenorhabditis elegans to identify a family of selective imidazothiazole nematicides, called selectivins, that undergo cytochrome p450-dependent bioactivation exclusively in nematodes. At low parts-per-million concentrations, selectivins perform comparably well with commercial nematicides to control root infection by Meloidogyne incognita - the worlds most destructive plant-parasitic nematode. Tests against a wide range of phylogenetically diverse non-target systems demonstrate that selectivins are more nematode-selective than nearly all marketed nematicides. Thus, selectivins are first-in-class bioactivated nematode controls that provide efficacy as well as much-needed nematode selectivity.

pharmacology and toxicology↗

bioRxiv2022

A Nematode-Selective Potentiator of Organophosphate and Carbamate Agrochemicals

Nematode parasites of humans, livestock and crops pose a significant burden on human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we present a pipeline that exploits multiple motor outputs of the model nematode C. elegans for nematicide discovery. This pipeline yielded multiple compounds that selectively kill and/or immobilize diverse nematode parasites. We focus on one compound that induces violent convulsions and paralysis that we call Nementin. We find that Nementin agonizes neuronal dense core vesicle release, which in turn agonizes cholinergic signaling. Consequently, Nementin synergistically enhances the potency of widely-used non-selective acetylcholinesterase inhibitors (AChEIs), but in a nematode-selective manner. Nementin therefore has the potential to reduce the environmental impact of toxic AChEI pesticides used to control nematode infections and infestations. Significance StatementParasitic nematodes pose a considerable burden to human health and food security. Small molecules that have traditionally been used to control these parasites have either been banned because of toxicity concerns or are being rendered ineffective because of the evolution of resistance. Significant gaps in our nematicidal toolkit are therefore becoming an alarming problem. Here, we describe our discovery of Nementin, a small molecule that disrupts the nematode nervous system but is ineffective against non-targeted organisms. We find that Nementin also enhances the activity of non-selective pesticides but does so in a nematode-selective manner. Hence, Nementin is an innovative solution to combat parasitic nematodes in a safe and phylum-selective manner. One-Sentence SummaryA C. elegans-based screening pipeline identifies a selective nematicide that also potentiates acetylcholinesterase inhibitors.

pharmacology and toxicology↗

bioRxiv2017

Whole genome sequences of the raspberry and strawberry pathogens Phytophthora rubi and P. fragariae

Phytophthora rubi and P. fragariae are two closely related oomycete plant pathogens that exhibit strong morphological and physiological similarities, but are specialized to infect different hosts of economic importance, namely raspberry and strawberry. Here, we report the draft genome sequences of these two Phytophthora species as a first step towards understanding the genomic processes underlying plant host adaptation in these pathogens.

genomics↗