A pair of enantiomeric 5-oxabicyclic[4.3.0]lactam derivatives and one new polyketide from the marine-derived fungus Penicillium griseofulvum

A pair of enantiomeric 4-oxabicyclic[4.3.0]lactam derivatives, (+)- and (?)-penicilactam A (1), and one new polyketide derivative penicitrinone F (2) were isolated from the marine-derived fungus Penicillium griseofulvum GT-10. Their structures and absolute configurations were elucidated through extensive spectroscopic analyses combined with the calculated ECD spectra. Penicitrinone F (2) had moderate inhibitory activity towards Bacillus subtilis with a MIC value of 6.3 μM.     

Enzymatic formation of an unnatural methylated triketide by plant type III polyketide synthases

Octaketide synthase, a novel plant-specific type III polyketide synthase from Aloe arborescens, efficiently accepted (2RS)-methylmalonyl-CoA as a sole substrate to produce 6-ethyl-4-hydroxy-3,5-dimethyl-2-pyrone. On the other hand, a tetraketide-producing chalcone synthase from Scutellaria baicalensis and a diketide-producing benzalacetone synthase from Rheum palmatum also yielded the unnatural methylated C₉ triketide pyrone as a single product by sequential decarboxylative condensations of three molecules of (2RS)-methylmalonyl-CoA.     

Microbial pretreatment of biomass

Typical pretreatment requires high-energy (steam and electricity) and corrosion-resistant, high-pressure reactors. A review of the literature suggests that fungal pretreatment could potentially lower the severity requirements of acid, temperature and time. These reductions in severity are also expected to result in less biomass degradation and consequently lower inhibitor concentrations compared to conventional thermochemical pretreatment. Furthermore, potential advantages of fungal pretreatment of agricultural residues, such as corn stover, are suggested by its effectiveness in improving the cellulose digestibility of many types of forage fiber and agricultural wastes. Our preliminary tests show a three- to five-fold improvement in enzymatic cellulose digestibility of corn stover after pretreatment with Cyathus stercoreus; and a ten- to 100-fold reduction in shear force needed to obtain the same shear rate of 3.2 to 7 rev/s, respectively, after pretreatment with Phanerochaete chrysosporium.     

Mesoporous cadmium sulfide nanoparticles derived from a new cadmium anthranilato complex: Characterization and induction of morphological abnormalities in pathogenic fungi

A cadmium complex of the general formula Cd(C₁₃H₉O₂NCl)₂(H₂O)₂ {C₁₃H₉O₂NCl = 2-(4-chlorophenylamino)benzoate} was synthesized and characterized regarding its CHN data, solution molar conductivity and spectroscopic (UV–Vis. and IR) properties. Cadmium sulfide nanoparticles (CdS NPs) were grown form the microcrystalline complex and thiourea via a hydrothermal route. The as-prepared NPs were assigned based on X-ray powder diffraction (PXRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and Brunauer – Emmett – Teller (BET) surface area measurements. The CdS absorption and emission spectra were also recorded that revealed an energy gap of 2.47 eV and large Stokes shift of 130 nm. For the as-prepared NPs, the measurements have also indicated a mesoporous structure and an average particle size of 20–28 nm associated with an average pore diameter of 11.21 nm. The as-synthesized CdS NPs acted as antifungal controlling agent against human and plant pathogenic fungi of serious environmental and health concerns. The NPs at concentration of 200 ppm inhibited several fungi with inhibition efficiency of 100% against Aspergillus ustus Au-28. The nanoparticles induced morphological abnormalities in fungal mycelia, conidia and vesicle. Additionally, they inhibited the conidia septum formation, accelerated the chlamydospores generation and enlarged the yeast cells.     

A field scale model for the spread of fungal diseases in crops: the example of a powdery mildew epidemic over a large vineyard

The aim of this article is to derive an asymptotic two‐scale model for the propagation of a fungal disease over a large vineyard. The original model is based on a singularly perturbed system of two linear reaction‐diffusion equations coupled with a set of nonlinear ordinary differential equations in a highly heterogeneous medium. We prove the well‐posedness of the asymptotic model and obtain a convergence result confirmed by numerical simulations. Copyright © 2014 John Wiley & Sons, Ltd.     

Biodegradation of γ-sterilised biomedical polyolefins under composting and fungal culture environments

Polyolefin-based commodities are widely used as biomedical devices and food packaging after γ-sterilisation. The aim of the present work was to study the effect of γ-sterilisation on the biodegradation of polyolefins. Films of isotactic polypropylene, high-density polyethylene and ethylene-propylene (EP) copolymers were sterilised under γ-radiation with doses of 10 and 25 kGy. Neat and sterilised samples were incubated in compost and fungal culture environments. The changes in functional groups, surface morphology and chain scission in polymer chains were characterized by FTIR spectroscopy, SEM and viscometric measurements, respectively. A gradual decrease in intrinsic viscosity [η] and increase in carbonyl and hydroxyl regions in FTIR spectra were found for the γ-sterilised samples as a function of increasing dose. Polypropylene was found to be more susceptible to both radio-oxidation and biodegradation. It was observed that in case of ethylene-propylene copolymers, extent of γ-sterilisation and/or biodegradation depends on the composition and distribution of comonomers. Important surface erosion was detected by SEM, for higher sterilisation doses, after composting.     

Aloeresin H, a new polyketide constituent of Cape aloe

A new constituent, aloeresin H (1), was isolated from Cape aloe, a bittering and laxative agent. Its structure was elucidated by degradation experiments combined with 1D and 2D NMR data. Aloeresin H represents the first C,C-diglucoside discovered in commercial samples of the drug and its polyketide origin can be interpreted in terms of two-chain condensation. Possible conformations of the virtual aglycone were obtained as energy minima by quantum mechanical calculations and were found to be consistent with particular NOE associations observed in the original glucoside.     

Influence of the thermal modification of controlled porosity glass on the affinity chromatography of fungal proteins

Summary The properties and the coverage density of chemically bonded phases depend among others on the properties of their supports. Controlled-porosity glasses (CPG) are materials used as a support of bio-active ligands. Their network mainly consist of SiO₂ as well as of a small amount of B₂O₃ and Na₂O. The characteristic feature of porous glasses is the possibility of a change in the surface boron concentration leading to the change of the properties of their surface.This paper deals with the results of the separation of fungal proteins on packings consisting of vanillin bonded to CPG with different boron concentration on its surface. It appears from the data obtained that the changes in the affinity of the fungal proteins to the packing are related to the extend of the thermal treatment of the CPG. The protein fractions separated by chromatography were confirmed to be homogeneous by poly-acryloamide gel disc electrophoresis.     

New Kendomycin Derivative Isolated from Streptomyces sp. Cl 58-27

In the course of screening new streptomycete strains, the strain Streptomyces sp. Cl 58-27 caught our attention due to its interesting secondary metabolite production profile. Here, we report the isolation and characterization of an ansamycin natural product that belongs structurally to the already known kendomycins. The structure of the new kendomycin E was elucidated using NMR spectroscopy, and the corresponding biosynthetic gene cluster was identified by sequencing the genome of Streptomyces sp. Cl 58-27 and conducting a detailed analysis of secondary metabolism gene clusters using bioinformatic tools.