SCAM Detective: Accurate Predictor of Small, Colloidally Aggregating Molecules.

Small, colloidally aggregating molecules (SCAMs) are the most common source of false positives in high-throughput screening (HTS) campaigns. Although SCAMs can be experimentally detected and suppressed by the addition of detergent in the assay buffer, detergent sensitivity is not routinely monitored in HTS. Computational methods are thus needed to flag potential SCAMs during HTS triage.

UDP-4-Keto-6-Deoxyglucose, a Transient Antifungal Metabolite, Weakens the Fungal Cell Wall Partly by Inhibition of UDP-Galactopyranose Mutase.

Can accumulation of a normally transient metabolite affect fungal biology? UDP-4-keto-6-deoxyglucose (UDP-KDG) represents an intermediate stage in conversion of UDP-glucose to UDP-rhamnose. Normally, UDP-KDG is not detected in living cells, because it is quickly converted to UDP-rhamnose by the enzyme UDP-4-keto-6-deoxyglucose-3,5-epimerase/-4-reductase (ER). We previously found that deletion of the gene in resulted in accumulation of UDP-KDG to levels that were toxic to the fungus due to destabilization of the cell wall.

BcXYG1, a Secreted Xyloglucanase from , Triggers Both Cell Death and Plant Immune Responses.

In search of cell death-inducing proteins, we found a xyloglucanase (BcXYG1) that induced strong necrosis and a resistance response in dicot plants. Expression of the gene was strongly induced during the first 12 h post inoculation, and analysis of disease dynamics using PathTrack showed that a strain overexpressing produced early local necrosis, supporting a role of BcXYG1 as an early cell death-inducing factor. The xyloglucanase activity of BcXYG1 was not necessary for the induction of necrosis and plant resistance, as a mutant of BcXYG1 lacking the xyloglucanase enzymatic activity retained both functions.

A four-gene operon in produces two rare spore-decorating sugars.

Bacterial glycan structures on cell surfaces are critical for cell-cell recognition and adhesion and in host-pathogen interactions. Accordingly, unraveling the sugar composition of bacterial cell surfaces can shed light on bacterial growth and pathogenesis. Here, we found that two rare sugars with a 3--methyl-6-deoxyhexose structure were linked to spore glycans in ATCC 14579 and ATCC 10876.

Rhamnose synthase activity is required for pathogenicity of the vascular wilt fungus Verticillium dahliae.

The initial interaction of a pathogenic fungus with its host is complex and involves numerous metabolic pathways and regulatory proteins. Considerable attention has been devoted to proteins that play a crucial role in these interactions, with an emphasis on so-called effector molecules that are secreted by the invading microbe to establish the symbiosis. However, the contribution of other types of molecules, such as glycans, is less well appreciated.

Genetic alteration of UDP-rhamnose metabolism in Botrytis cinerea leads to the accumulation of UDP-KDG that adversely affects development and pathogenicity.

Botrytis cinerea is a model plant-pathogenic fungus that causes grey mould and rot diseases in a wide range of agriculturally important crops. A previous study has identified two enzymes and corresponding genes (bcdh, bcer) that are involved in the biochemical transformation of uridine diphosphate (UDP)-glucose, the major fungal wall nucleotide sugar precursor, to UDP-rhamnose. We report here that deletion of bcdh, the first biosynthetic gene in the metabolic pathway, or of bcer, the second gene in the pathway, abolishes the production of rhamnose-containing glycans in these mutant strains.

Pen and Pal are nucleotide-sugar dehydratases that convert UDP-GlcNAc to UDP-6-deoxy-D-GlcNAc-5,6-ene and then to UDP-4-keto-6-deoxy-L-AltNAc for CMP-pseudaminic acid synthesis in Bacillus thuringiensis.

CMP-pseudaminic acid is a precursor required for the O-glycosylation of flagellin in some pathogenic Gram-negative bacteria, a process known to be critical in bacterial motility and infection. However, little is known about flagellin glycosylation in Gram-positive bacteria. Here, we identified and functionally characterized an operon, named Bti_pse, in Bacillus thuringiensis israelensis ATCC 35646, which encodes seven different enzymes that together convert UDP-GlcNAc to CMP-pseudaminic acid.