A new role for veratryl alcohol: regulation of synthesis of lignocellulose-degrading enzymes in the ligninolytic ascomyceteous fungus, Botryosphaeria sp.; influence of carbon source

A new physiological role for veratryl alcohol in fungi important in the biodegradation of the lignified plant cell wall is presented. Botryosphaeria sp., grown on starch, pectin, cellulose or xylan produced amylase, pectinase, cellulase, xylanase and laccase, whereas glucose and xylose repressed the synthesis of cellulase and xylanase, but not laccase. When cultured on each of these substrates in the presence of veratryl alcohol, laccase activity increased but the activities of amylase, pectinase, cellulase and xylanase significantly decreased. Basal medium containing softwood kraft lignin in the presence of veratryl alcohol induced laccases above constitutive levels. Ethyl alcohol also stimulated laccase production.     

Aerenchyma formation and recovery from hypoxia of the flooded root system of nodulated soybean

BACKGROUND AND AIMS: Flooding results in hypoxia of the root system to which N2 fixation of nodulated roots can be especially sensitive. Morphological adaptions, such as aerenchyma formation, can facilitate the diffusion of oxygen to the hypoxic tissues. Using soybean, the aim of the study was to characterize the morphological response of the nodulated root system to flooding and obtain evidence for the recovery of N metabolism. METHODS: Sections from submerged tissues were observed by light microscopy, while sap bleeding from the xylem was analysed for nitrogenous components. KEY RESULTS: Flooding resulted in the rapid formation of adventitious roots and aerenchyma between the stem (immediately above the water line), roots and nodules. In the submerged stem, taproot, lateral roots and adventitious roots, lysigenous aerenchyma arose initially in the cortex and was gradually substituted by secondary aerenchyma arising from cells derived from the pericycle. Nodules developed aerenchyma from cells originating in the phellogen but nodules situated at depths greater than 7-8 cm showed little or no aerenchyma formation. As a result of aerenchyma formation, porosity of the taproot increased substantially between the 4th and 7th days of flooding, coinciding with the recovery of certain nitrogenous products of N metabolism of roots and nodules transported in the xylem. Thus, on the first day of flooding there was a sharp decline in xylem ureides and glutamine (products of N2 fixation), together with a sharp rise in alanine (product of anaerobic metabolism). Between days 7 and 10, recovery of ureides and glutamine to near initial levels was recorded while recovery of alanine was partial. CONCLUSIONS: N metabolism of the nodulated soybean root system can recover at least partially during a prolonged period of flooding, a process associated with aerenchyma formation.     

Overexpression of NRPS4 leads to increased surface hydrophobicity in fusarium graminearum

The plant pathogen Fusarium graminearum is the infamous cause of Fusarium head blight worldwide resulting in significant losses of yield and reduced grain feed quality. It also has the potential to produce a range of small bioactive peptides produced by the non ribosomal peptide synthetases (NRPSs). Most of these are unknown as F. graminearum contains 19 NRPS encoding genes, but only three have been assigned products. For the first time, we use deletion and overexpression mutants to investigate the functions and product of NRPS4 in F. graminearum. Deletion of NRPS4 homologues in Alternaria brassicicola and Cochloibolus heterostrophus has been shown to result in mutants unable to repel water. In a time study of surface hydrophobicity we observed that water droplets could penetrate 7 d old colonies of the NRPS4 deletion mutants. Loss in ability to repel water was first observed on 13 d old cultures of the wild type strain, whereas the overexpression strain remained water repellant throughout the 38 d time study. The conidia of both mutants were examined and those of the overexpression mutant showed distinct morphological differences in form of collapsed cells. These observations might suggest that the peptide product of NRPS4 could be an architectural factor in the cell walls of Fusarium or an indirect regulator of hydrophobicity.     

Melanoma Inhibitory Activity (MIA) increases the invasiveness of pancreatic cancer cells

Background  

Melanoma inhibitory activity (MIA) is a small secreted protein that interacts with extracellular matrix proteins. Its over-expression promotes the metastatic behavior of malignant melanoma, thus making it a potential prognostic marker in this disease. In the present study, the expression and functional role of MIA was analyzed in pancreatic cancer by quantitative real-time PCR (QRT-PCR), immunohistochemistry, immunoblot analysis and ELISA. To determine the effects of MIA on tumor cell growth and invasion, MTT cell growth assays and modified Boyden chamber invasion assays were used.     

A Persistence Detector for Metabolic Network Rewiring in an Animal

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Handling and environmental enrichment do not rescue learning and memory impairments in alphaCamKII(T286A) mutant mice

Environmental enrichment and postnatal handling have been shown to improve learning and memory in the Morris water maze, and to rescue impairments caused by genetic modification, age or genetic background. Mice with a targeted point mutation that prevents autophosphorylation at threonine-286 of the α-isoform of the Ca²⁺/calmodulin-dependent kinase II have impaired hippocampus-dependent and -independent strategy learning and memory in the water maze. We have investigated whether these impairments can be rescued with a combination of postnatal handling and environmental enrichment in a hybrid genetic background. Severe impairments were seen in acquisition and probe trials in both enriched and nonenriched mutants, indicating that enrichment did not rescue the learning and memory impairments. However, enrichment did rescue a specific performance deficit; enhanced floating behaviour, in the mutants. In summary, we have shown the lack of autophosphorylation of the α-isoform of the Ca²⁺/calmodulin-dependent kinase II prevents enrichment-induced rescues of strategy learning and memory impairments. Furthermore, we have established that there are enrichment mechanisms that are independent of this autophosphorylation.