Spectrophotometric-Based Assay to Quantify Relative Enzyme-Mediated Degradation of Commercially Available Bioplastics.

We present a spectrophotometric-based assay to identify enzymes that degrade commercially available bioplastics. Bioplastics comprise aliphatic polyesters with hydrolysis-susceptible ester bonds and are proposed as a replacement for petroleum-based plastics that accumulate in the environment. Unfortunately, many bioplastics can also persist in environments including seawater and waste centers.

Octopamine receptor gene influences social grouping in the masked birch caterpillar.

Objective: Group-living plays a key role in the success of many insects, but the mechanisms underlying group formation and maintenance are poorly understood. Here we use the masked birch caterpillar, Drepana arcuata, to explore genetic influences on social grouping. These larvae predictably transition from living in social groups to living solitarily during the 3rd instar of development.

A metabolomic study of vegetative incompatibility in Cryphonectria parasitica.

Vegetative incompatibility (VI) is a form of non-self allorecognition in filamentous fungi that restricts conspecific hyphal fusion and the formation of heterokaryons. In the chestnut pathogenic fungus, Cryphonectria parasitica, VI is controlled by six vic loci and has been of particular interest because it impedes the spread of hypoviruses and thus biocontrol strategies. We use nuclear magnetic resonance and high-resolution mass spectrometry to characterize alterations in the metabolome of C.

Propionic acid disrupts endocytosis, cell cycle, and cellular respiration in yeast.

Objective: We previously identified propionic acid as a microbially-produced volatile organic compound with fungicidal activity against several pathogenic fungi. The purpose of this work is to better understand how propionic acid affects fungi by examining some of the effects of this compound on the yeast cell.

Results: We show that propionic acid causes a dramatic increase in the uptake of lucifer yellow in yeast cells, which is consistent with enhanced endocytosis.

Transcriptome analysis implicates secondary metabolite production, redox reactions, and programmed cell death during allorecognition in Cryphonectria parasitica.

The underlying molecular mechanisms of programmed cell death associated with fungal allorecognition, a form of innate immunity, remain largely unknown. In this study, transcriptome analysis was used to infer mechanisms activated during barrage formation in vic3-incompatible strains of Cryphonectria parasitica, the chestnut blight fungus. Pronounced differential expression occurred in barraging strains of genes involved in mating pheromone (mf2-1, mf2-2), secondary metabolite production, detoxification (including oxidative stress), apoptosis-related, RNA interference, and HET-domain genes.

Transcriptome analysis of a social caterpillar, Drepana arcuata: De novo assembly, functional annotation and developmental analysis.

The masked birch caterpillar, Drepana arcuata, provides an excellent opportunity to study mechanisms mediating developmental changes in social behaviour. Larvae transition from being social to solitary during the 3rd instar, concomitant with shifts in their use of acoustic communication. In this study we characterize the transcriptome of D.

Volatile organic compounds kill the white-nose syndrome fungus, , in hibernaculum sediment.

, the fungal pathogen that causes white-nose syndrome, has killed millions of bats across eastern North America and continues to threaten new bat populations. The spread and persistence of has likely been worsened by the ability of this fungus to grow as a saprotroph in the hibernaculum environment. Reducing the environmental growth of may improve bat survival.

Mode of action of nisin on .

Nisin is a class I polycyclic bacteriocin produced by the bacterium , which is used extensively as a food additive to inhibit the growth of foodborne Gram-positive bacteria. Nisin also inhibits growth of Gram-negative bacteria when combined with membrane-disrupting chelators such as citric acid. To gain insight into nisin's mode of action, we analyzed chemical-genetic interactions and identified nisin-sensitive strains in the Keio library of knockout mutants.

Clonal evolution and genome stability in a 2500-year-old fungal individual.

Individuals of the basidiomycete fungus Armillaria are well known for their ability to spread from woody substrate to substrate on the forest floor through the growth of rhizomorphs. Here, we made 248 collections of A. gallica in one locality in Michigan's Upper Peninsula.

Echinacea biotechnology: advances, commercialization and future considerations.

Context: Plants of the genus Echinacea (Asteraceae) are among the most popular herbal supplements on the market today. Recent studies indicate there are potential new applications and emerging markets for this natural health product (NHP).

Objective: This review aims to synthesize recent developments in Echinacea biotechnology and to identify promising applications for these advances in the industry.

Zinc oxide and silver nanoparticles toxicity in the baker's yeast, Saccharomyces cerevisiae.

Engineered nanomaterials (ENMs) are increasingly incorporated into a variety of commercial applications and consumer products; however, ENMs may possess cytotoxic properties due to their small size. This study assessed the effects of two commonly used ENMs, zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs), in the model eukaryote Saccharomyces cerevisiae. A collection of ≈4600 S.

Balancing selection at nonself recognition loci in the chestnut blight fungus, Cryphonectria parasitica, demonstrated by trans-species polymorphisms, positive selection, and even allele frequencies.

Balancing selection has been inferred in diverse organisms for nonself recognition genes, including those involved in immunity, mating compatibility, and vegetative incompatibility. Although selective forces maintaining polymorphisms are known for genes involved in immunity and mating, mechanisms of balancing selection for vegetative incompatibility genes in fungi are being debated. We hypothesized that allorecognition and its consequent inhibition of virus transmission contribute to the maintenance of polymorphisms in vegetative incompatibility loci (vic) in the chestnut blight fungus, Cryphonectria parasitica.

The sensitivity of the yeast, , to acetic acid is influenced by and .

The presence of acetic acid during industrial alcohol fermentation reduces the yield of fermentation by imposing additional stress on the yeast cells. The biology of cellular responses to stress has been a subject of vigorous investigations. Although much has been learned, details of some of these responses remain poorly understood.

Microbial inhibitors of the fungus Pseudogymnoascus destructans, the causal agent of white-nose syndrome in bats.

Pseudogymnoascus destructans, the fungus that causes white-nose syndrome in hibernating bats, has spread across eastern North America over the past decade and decimated bat populations. The saprotrophic growth of P. destructans may help to perpetuate the white-nose syndrome epidemic, and recent model predictions suggest that sufficiently reducing the environmental growth of P.

Antifungal Saponins from the Maya Medicinal Plant Cestrum schlechtendahlii G. Don (Solanaceae).

Bioassay-guided fractionation of the crude extract (80% EtOH) of the leaves of Cestrum schlechtendahlii, a plant used by Q'eqchi' Maya healers for treatment of athlete's foot, resulted in the isolation and identification of two spirostanol saponins (1 and 2). Structure elucidation by MS, 1D-NMR, and 2D-NMR spectroscopic methods identified them to be the known saponin (25R)-1β,2α-dihydroxy-5α-spirostan-3-β-yl-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-galactopyranoside (1) and new saponin (25R)-1β,2α-dihydroxy-5α-spirostan-3-β-yl-O-β-D-galactopyranoside (2). While 2 showed little or no antifungal activity at the highest concentration tested, 1 inhibited growth of Saccharomyces cerevisiae (minimum inhibitory concentration (MIC) of 15-25 μM), Candida albicans, Cryptococcus neoformans, and Fusarium graminearum (MIC of 132-198 μM).

Metabolism of n-C10:0 and n-C11:0 fatty acids by Trichoderma koningii, Penicillium janthinellum and their mixed culture: I. Biomass and CO2 production, and allocation of intracellular lipids.

The capacity of two soil fungi, Trichoderma koningii and Penicillium janthinellum, to oxidize n-C10:0 and n-C11:0 fatty acids to CO2 and store intracellular lipids during growth is unknown. This article reports for the first time the metabolism of decanoic acid (DA, C10:0), undecanoic acid (UDA, n-C11:0), a mixture of the acids (UDA+DA) and a mixture of UDA+ potato dextrose broth (PDB) by T. koningii and P.

Elimination of bioweapons agents from forensic samples during extraction of human DNA.

Collection of DNA for genetic profiling is a powerful means for the identification of individuals responsible for crimes and terrorist acts. Biologic hazards, such as bacteria, endospores, toxins, and viruses, could contaminate sites of terrorist activities and thus could be present in samples collected for profiling. The fate of these hazards during DNA isolation has not been thoroughly examined.

Antimicrobial and P450 inhibitory properties of common functional foods.

Purpose: To study the effect of functional foods on human cytochrome P450 (CYP) and the gut bacterial microflora that may potentially affect drug metabolism and ultimately affect human health and wellness.

Methods: This study examined a variety of food plants from the Apiaceae, Fabaceae, and Lamiaceae families for their inhibitory potential on cytochrome 2D6-, 3A4-, 3A5-, and 3A7-mediated metabolism. The antimicrobial effects of these samples were also investigated with 7 selected bacterial surrogate species to determine potential effects on the gut microflora.

Experimental evolution of bet hedging under manipulated environmental uncertainty in Neurospora crassa.

All organisms are faced with environmental uncertainty. Bet-hedging theory expects unpredictable selection to result in the evolution of traits that maximize the geometric-mean fitness even though such traits appear to be detrimental over the shorter term. Despite the centrality of fitness measures to evolutionary analysis, no direct test of the geometric-mean fitness principle exists.

A global investigation of gene deletion strains that affect premature stop codon bypass in yeast, Saccharomyces cerevisiae.

Protein biosynthesis is an orderly process that requires a balance between rate and accuracy. To produce a functional product, the fidelity of this process has to be maintained from start to finish. In order to systematically identify genes that affect stop codon bypass, three expression plasmids, pUKC817, pUKC818 and pUKC819, were integrated into the yeast non-essential loss-of-function gene array (5000 strains).

The antifungal eugenol perturbs dual aromatic and branched-chain amino acid permeases in the cytoplasmic membrane of yeast.

Eugenol is an aromatic component of clove oil that has therapeutic potential as an antifungal drug, although its mode of action and precise cellular target(s) remain ambiguous. To address this knowledge gap, a chemical-genetic profile analysis of eugenol was done using ∼4700 haploid Saccharomyces cerevisiae gene deletion mutants to reveal 21 deletion mutants with the greatest degree of susceptibility. Cellular roles of deleted genes in the most susceptible mutants indicate that the main targets for eugenol include pathways involved in biosynthesis and transport of aromatic and branched-chain amino acids.

Thymol antifungal mode of action involves telomerase inhibition.

The antifungal mode of action of thymol was investigated by a chemical-genetic profile analysis. Growth of each of ~4700 haploid Saccharomyces cerevisiae gene deletion mutants was monitored on medium with a subinhibitory concentration (50 μg/ml) of thymol and compared to growth on non-thymol control medium. This analysis revealed that, of the 76 deletion mutants with the greatest degree of susceptibility to thymol, 29% had deletions in genes involved in telomere length maintenance.

Disruption of protein synthesis as antifungal mode of action by chitosan.

The antimicrobial activity of chitosan has been acknowledged for more than 30 years and yet its mode-of-action remains ambiguous. We analyzed chemical-genetic interactions of low-molecular weight chitosan using a collection of ≈ 4600 S. cerevisiae deletion mutants and found that 31% of the 107 mutants most sensitive to chitosan had deletions of genes related primarily to functions involving protein synthesis.

Trans-species activity of a nonself recognition domain.

Background: The ability to distinguish nonself from self is a fundamental characteristic of biological systems. In the filamentous fungus Neurospora crassa, multiple incompatibility genes mediate nonself recognition during vegetative growth. One of these genes, un-24, encodes both nonself recognition function and the large subunit of a type I ribonucleotide reductase, an evolutionarily conserved enzyme that is essential for the conversion of NDP precursors into dNDPs for use in DNA synthesis.

Large-scale investigation of oxygen response mutants in Saccharomyces cerevisiae.

A genome-wide screen of a yeast non-essential gene-deletion library was used to identify sick phenotypes due to oxygen deprivation. The screen provided a manageable list of 384 potentially novel as well as known oxygen responding (anoxia-survival) genes. The gene-deletion mutants were further assayed for sensitivity to ferrozine and cobalt to obtain a subset of 34 oxygen-responsive candidate genes including the known hypoxic gene activator, MGA2.