Building the cell wall is flipping difficult The of bacteria constructed from a polysaccharide called peptidoglycan (PG). It forms matrix that surrounds cells and essential for integrity cytoplasmic membrane. Many our most successful antibiotics target PG synthesis. synthetic pathway involves assembly sugar building blocks on lipid carrier at inner face reactions produce this so-called II precursor enzymes catalyze them have been known decades. However, identity flippase enzyme “flips” in...

The soil bacterium Bacillus subtilis forms biofilms on surfaces and at air-liquid interfaces. It was previously reported that these disassemble late in their life cycle conditioned medium from late-stage inhibits biofilm formation. Such contained a mixture of D-leucine, D-methionine, D-tryptophan, D-tyrosine to inhibit formation via the incorporation D-amino acids into cell wall. Here, we show L-amino were able specifically reverse inhibitory effects cognate acids. We also inhibited growth...

The peptidoglycan precursor, Lipid II, produced in the model Gram-positive bacterium Bacillus subtilis differs from II found Gram-negative bacteria such as Escherichia coli by a single amidation on peptide side chain. How this difference affects cross-linking activity of penicillin-binding proteins (PBPs) that assemble cells has not been investigated because B. was previously available. Here we report synthesis and its use purified PBP1 E. PBP1A. While enzymes both organisms assembled into...

Penicillin-binding proteins (PBPs) are involved in the synthesis and remodeling of bacterial peptidoglycan (PG). Staphylococcus aureus expresses four PBPs. Genetic studies S. have implicated PBP4 formation highly cross-linked PG, but biochemical not reached a consensus on its primary enzymatic activity. Using synthetic Lipid II, we show here that preferentially acts as transpeptidase (TP) vitro. Moreover, it is PBP primarily responsible for incorporating exogenous d-amino acids into cellular...

In Escherichia coli, the bifunctional penicillin-binding proteins (PBPs), PBP1A and PBP1B, play critical roles in final stage of peptidoglycan (PG) biosynthesis. These synthetic enzymes each possess a PG glycosyltransferase (PGT) domain transpeptidase (TP) domain. Recent genetic experiments have shown that PBP1B require an outer membrane lipoprotein, LpoA LpoB, respectively, to function properly vivo. Here, we use complementary assays show LpoB increase PGT TP activities their cognate PBPs,...

Laboratory experiments were conducted to unravel synthetic routes form three C2H4O isomers—acetaldehyde (CH3CHO), ethylene oxide (c-C2H4O), and vinyl alcohol (CH2CHOH)—in extraterrestrial ices via electronic energy transfer processes initiated by electrons in the track of MeV ion trajectories. Here we present results electron irradiation on a 2 : 1 mixture carbon dioxide (CO2) (C2H4). Our studies suggest that suprathermal oxygen atoms can add carbon-carbon π bond an molecule initially...

We conducted a screening campaign to investigate fungi as source for new antimalarial compounds. A subset of our fungal collection comprising Chinese mangrove endophytes provided over 5000 lipophilic extracts. developed an accelerated discovery program based on small-scale cultivation crude extract and high-throughput malaria assay. Criteria hits were high priority subjected scale-up cultivation. Extracts from large scale fractionated these fractions both in vitro cytotoxicity screening....

Polyamines (PAs) are ubiquitous polycations found in plants and other organisms that essential for growth, development, resistance against abiotic biotic stresses. The role of PAs plant disease depends on the relative abundance higher [spermidine (Spd), spermine (Spm)] vs. diamine putrescine (Put) PA catabolism. With respect to pathogen, required achieve successful pathogenesis host. Maize is an important food feed crop, which highly susceptible Aspergillus flavus infection. Upon infection,...

Introduction Aspergillus flavus is an opportunistic pathogenic fungus that infects oilseed crops worldwide. When colonizing plants, it produces mycotoxins, including carcinogenic compounds such as aflatoxins. Mycotoxin contamination results in important economic and health impact. The design of new strategies to control A. colonization mycotoxin paramount. Methods biocontrol potential a promising isolate Pseudomonas spp., 20EI1 against was assessed using bioassays microscopy. To further...

Forkhead transcription factors regulate several important biological processes in many eukaryotic species including fungi. Bioinformatic analysis of the Aspergillus flavus genome revealed four putative forkhead factor genes. Genetic disruption (AFLA_005634), a homolog nidulans fhpA/fkhA gene (AN4521), that fhpA is negative regulator both asexual spore production and aflatoxin B1 A. flavus. Furthermore, caused complete loss sclerotial formation. Overexpression to become more sensitive sodium...

Aflatoxins are carcinogenic and mutagenic mycotoxins that contaminate food feed. The objective of our research is to predict aflatoxin outbreaks in Texas-grown maize using dynamic geospatial data from remote sensing satellites, soil properties data, meteorological by an ensemble models. We developed three model pipelines: two included mechanistic models use weekly risk indexes (ARIs) as inputs, one a weather-centric model; all incorporated inputs. For the mechanistic-dependent models, ARIs...

Target-based drug discovery for Alzheimer's disease (AD) centered on modulation of the amyloid β peptide has met with limited success. Therefore, recent efforts have focused targeting microtubule-associated protein tau. Tau pathologically accumulates in more than 15 neurodegenerative diseases and is most closely linked postsymptomatic progression AD. We endeavored to identify compounds that decrease tau stability rather prevent its aggregation. An extract from Myrica cerifera...

The bacterial cell wall precursor, Lipid II, has a highly conserved structure among different organisms except for differences in the amino acid sequence of peptide side chain. Here, we report an efficient and flexible synthesis canonical II precursor required assembly Gram-negative peptidoglycan (PG). We use rapid LC/MS assay to analyze PG glycosyltransfer (PGT) transpeptidase (TP) activities Escherichia coli penicillin binding proteins PBP1A PBP1B show that native m-DAP residue chain is...

Aspergillus flavus is a soil-borne saprophyte and an opportunistic pathogen of both humans plants. This fungus not only causes disease in important food feed crops such as maize, peanut, cottonseed, tree nuts but also produces the toxic carcinogenic secondary metabolites (SMs) known aflatoxins. Polyamines (PAs) are ubiquitous polycations that influence normal growth, development, stress responses living organisms have been shown to play significant role fungal pathogenesis. Biosynthesis...

We have isolated meridianins A, B, C, and E from the Antarctic tunicate Synoicum sp. In process of verifying structure these compounds it was noted that physical data reported for bore a striking resemblance to psammopemmins. The psammopemmins are alkaloids bearing similar structures meridianins, but sponge Psammopemma To verify originally proposed psammopemmin compound synthesized. By comparing 1H 13C NMR synthetic A with meridianin we infer correct is actually A.

Homeobox proteins, a class of well conserved transcription factors, regulate the expression targeted genes, especially those involved in development. In filamentous fungi, homeobox genes are required for normal conidiogenesis and fruiting body formation. present study, we identified eight (hbx) aflatoxin-producing ascomycete, Aspergillus flavus, determined their respective role growth, conidiation sclerotial production. Disruption seven had little to no effect on fungal growth However,...

Aspergillus flavus is a saprophytic fungus that may colonize several important crops, including cotton, maize, peanuts and tree nuts. Concomitant with A. colonization its potential to secrete mycotoxins, of which the most prominent aflatoxin. Temperature, water activity (aw) carbon dioxide (CO2) are three environmental factors shown influence fungus-plant interaction, predicted undergo significant changes in next century. In this study, we used RNA sequencing better understand transcriptomic...

Maize (Zea mays L.) is a crop of major economic and food security importance globally. The fall armyworm (FAW), Spodoptera frugiperda, can devastate entire maize crops, especially in countries or markets that do not allow the use transgenic crops. Host-plant insect resistance an economical environmentally benign way to control FAW, this study sought identify lines, genes, pathways contribute FAW. Of 289 lines phenotyped for FAW damage artificially infested, replicated field trials over 3...