Identification of a cis-acting factor modulating the transcription of FUM1, a key fumonisin-biosynthetic gene in the fungal maize pathogen Fusarium verticillioides.

Fumonisins, toxic secondary metabolites produced by some Fusarium spp. and Aspergillus niger, have strong agro-economic and health impacts. The genes needed for their biosynthesis, named FUM, are clustered and co-expressed in fumonisin producers. In eukaryotes, coordination of transcription can be attained through shared transcription factors, whose specificity relies on the recognition of cis-regulatory elements on target promoters. A bioinformatic analysis on FUM promoters in the maize pathogens Fusarium verticillioides and Aspergillus niger identified a degenerated, over-represented motif potentially involved in the cis-regulation of FUM genes, and of fumonisin biosynthesis. The same motif was not found in various FUM homologues of fungi that do not produce fumonisins. Comparison of the transcriptional strength of the intact FUM1 promoter with a synthetic version, where the motif had been mutated, was carried out in vivo and in planta for F. verticillioides. The results showed that the motif is important for efficient transcription of the FUM1 gene.

Transcription of genes in the biosynthetic pathway for fumonisin mycotoxins is epigenetically and differentially regulated in the fungal maize pathogen Fusarium verticillioides.

When the fungal pathogen Gibberella moniliformis (anamorph, Fusarium verticillioides) colonizes maize and maize-based products, it produces class B fumonisin (FB) mycotoxins, which are a significant threat to human and animal health. FB biosynthetic enzymes and accessory proteins are encoded by a set of clustered and cotranscribed genes collectively named FUM, whose molecular regulation is beginning to be unraveled by researchers. FB accumulation correlates with the amount of transcripts from the key FUM genes, FUM1, FUM21, and FUM8. In fungi in general, gene expression is often partially controlled at the chromatin level in secondary metabolism; when this is the case, the deacetylation and acetylation (and other posttranslational modifications) of histones are usually crucial in the regulation of transcription. To assess whether epigenetic factors regulate the FB pathway, we monitored FB production and FUM1, FUM21, and FUM8 expression in the presence of a histone deacetylase inhibitor and verified by chromatin immunoprecipitation the relative degree of histone acetylation in the promoter regions of FUM1, FUM21, and FUM8 under FB-inducing and noninducing conditions. Moreover, we generated transgenic F. verticillioides strains expressing GFP under the control of the FUM1 promoter to determine whether its strength under FB-inducing and noninducing conditions was influenced by its location in the genome. Our results indicate a clear and differential role for chromatin remodeling in the regulation of FUM genes. This epigenetic regulation can be attained through the modulation of histone acetylation at the level of the promoter regions of the key biosynthetic genes FUM1 and FUM21, but less so for FUM8.

The ITS region as a taxonomic discriminator between Fusarium verticillioides and Fusarium proliferatum.

The maize pathogens Fusarium verticillioides (Fv) and Fusarium proliferatum (Fp) are morphologically very similar to one another, so Fp isolates have been often mistaken as Fusarium moniliforme (the former name of Fv). The only presently accepted morphological discriminator between these species is the presence/absence of polyphialides. Here, a collection of 100 Fusarium strains, isolated from infected maize kernels on plants grown in north-western Italy, were assigned as Fv or Fp on the basis of the presence/absence of polyphialides. This classification was tested on a subset of isolates by sexual crosses, ITS and calmodulin sequencing and AFLP profiling. An ITS-RFLP assay was extended to the full collection and to a number of Fv and Fp isolates of different geographical origin and hosts. The ITS region is proposed as taxonomically informative for distinguishing between Fp and Fv.

[Vascular pathology of surgical interest in drug addicts]. / Patologie vascolari di interesse chirurgico nei tossicodipendenti.

The incidence of vascular complications due to drug abuse is at present increasing due to new types of drugs and to the different ways of intake of such substances. The vascular complications related to drug abuse may affect venous, arterious and lymphatic districts and in particular: ischemia following intra-arterial injections, arterious and venous pseudoaneurysm, vasculitis, aneurysms, aortic dissections, abscesses complicated by erosions of vessels, arteriovenous fistulas, compartment syndrome, superficial and deep venous thrombosis, septic trombophlebitis, puffy hand syndrome. The scientific knowledge in this matter is incomplete because of the new pathological cases and the lack of information regarding the efficacy of different treatments. The authors report four patients affected by vascular pathologies due to drug abuse. In one case, a heroin addict has undergone multiple fasciotomies for compartimental syndrome arising because the patient maintained an innatural posture for several hours during an overdose coma. In a second case, a segmental right subclavear deep venous thrombosis has been treated by pharmacological therapy with satisfactory functional recovery of the arm. A third patient has been successfully submitted to intra-arterial pharmacological vasodilatation for generalised lower limbs vasospasm caused by drug abuse. In the last case, the voluntary swallowing of a great dose of cocaine caused the patient's death after multiple ischemic and hemorrhagic cerebral episodes. After the description of these cases, a review of the recent literature and some observations on this topic are presented. A better knowledge of vascular complications due to drug abuse should improve the therapeutical approach of these patients.

Variability of plasma viscosity in monoclonal IgM gammopathies.

Hyperviscosity syndromes can caused by both plasmatic and cellular factors. We have studied 20 patients affected by IgM gammopathy of different origin and 12 healthy subjects matched for sex and age, in order to evaluate the relation between paraprotein levels and plasma viscosity. We have observed a significant plasma viscosity increase only in 14 patients with monoclonal IgMk gammopathy. In the same patients was also evident an hyperviscosity syndrome. In the other 6 patients, with monoclonal IgM or polyclonal gammopathy and without clinical symptoms, plasma viscosity was only slightly increased. We have also observed a significant correlation between IgM and light chains (kappa, lambda) serum level and increased plasma viscosity. These results suggest that one can't consider all IgM gammopathies as cause of hyperviscosity syndrome.

[Erythrocyte filterability and relative viscosity in liver cirrhosis and chronic hepatitis]. / Filtrazione eritrocitaria e viscosità relativa nella cirrosi epatica e nella epatite cronica.

Fifty patients with liver disease, of whom twenty-four had chronic active hepatitis and twenty-three had liver cirrhosis, were studied and compared with thirty-nine age- and sex-matched controls. Whole blood, plasma and their relative viscosities and the main factors capable of influencing these parameters (Ht, fibrinogen, triglycerides, cholesterol, plasma glucose, total proteins and gamma-globulins) were tested. Whole blood filterability time and velocity of red blood cells (VRBC) were also determined. In ten patients deformability of erythrocytes was determined both in whole blood and in suspensions of RBC in buffer at a Ht of 10%. Whole blood filterability time was significantly increased in all subjects with liver disease. Corrected filterability time was increased only in the cirrhotic group associated with a significant decrease of Ht and fibrinogen and a slight increase in gamma globulins and plasma viscosity. Whole blood viscosity was in the normal range while relative viscosity was decreased in all patients. These findings suggest that both shape alterations of red cells (such as echinocytic shape) and modifications of plasma proteins probably lead to a decrease of red cell filtration in cirrhotic patients.

Low incidence of familial occurrence of thrombocythaemia and/or thrombocytosis.

Several reports have been published about familial polycythaemia vera (PV) but no information is available about the incidence of thrombocytosis in the same family. In our population of thrombocytosic patients, both with primary thrombocytosis (133 cases) and secondary (37 cases), we found only two family related subjects. One of them had PV and the other essential thrombocytosis (ET). Our results seem to indicate that familial thrombocytosis is a rare phenomenon, much less frequent then familial thrombocytopenia.

Study on a new chromogenic substrate for the prothrombin time determination.

The aim of our study was to evaluate the possibility of using a chromogenic substrate for the prothrombin time determination. The reagent used by us (Chromoquick) is composed of a human placenta thromboplastin and chromogenic substrate (Tos-Gly-Pro-Arg-5-amino-2-nitrobenzoic acid-isopropylamide), calcium chloride and a buffer. Normal subjects, patients with liver disease, patients on oral anticoagulant therapy, patients on heparin therapy, heterozygous and homozygous patients for prothrombin complex defects and other miscellaneous conditions have been investigated. The results of chromoquick have been related with standard prothrombin time obtained using a human placenta thromboplastin (Thromborel) and rabbit brain and lung thromboplastin (Simplastin). The normal range was 18-23 s for chromoquick and 13.5-15.5 s for the standard prothrombin times using Thromborel and Simplastin. In all groups of patients examined we noticed a significant correlation between the chromogenic and the classic prothrombin times with r values varying between +0.505 and +0.947. The statistical significance resulted from p values varying between less than 0.05 and less than 0.001. Only in the case of some heterozygotes for prothrombin complex factor defects the values obtained have not been unequivocal in the sense that in a few instances the heterozygotes seemed to escape detection. Therefore, it seems that the introduction of chromogenic substrates in laboratory practice for the prothrombin time determination is possible and can offer considerable advantages like standardization and automation. The only disadvantage may be caused by costs involved.