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Biomedical subjects

F Federici

Publications and source records attributed to F Federici.

At least 19 recordsLinked to original sources
PubMed2006

Role of autochthonous filamentous fungi in bioremediation of a soil historically contaminated with aromatic hydrocarbons.

Nine fungal strains isolated from an aged and heavily contaminated soil were identified and screened to assess their degradative potential. Among them, Allescheriella sp. strain DABAC 1, Stachybotrys sp. strain DABAC 3, and Phlebia sp. strain DABAC 9 were selected for remediation trials on the basis of Poly R-478 decolorization associated with lignin-modifying enzyme (LME) production. These autochthonous fungi were tested for the abilities to grow under nonsterile conditions and to degrade various aromatic hydrocarbons in the same contaminated soil. After 30 days, fungal colonization was clearly visible and was confirmed by ergosterol determination. In spite of subalkaline pH conditions and the presence of heavy metals, the autochthonous fungi produced laccase and Mn and lignin peroxidases. No LME activities were detected in control microcosms. All of the isolates led to a marked removal of naphthalene, dichloroaniline isomers, o-hydroxybiphenyl, and 1,1'-binaphthalene. Stachybotrys sp. strain DABAC 3 was the most effective isolate due to its ability to partially deplete the predominant contaminants 9,10-anthracenedione and 7H-benz[DE]anthracen-7-one. A release of chloride ions was observed in soil treated with either Allescheriella sp. strain DABAC 1 or Stachybotrys sp. strain DABAC 3, suggesting the occurrence of oxidative dehalogenation. The autochthonous fungi led to a significant decrease in soil toxicity, as assessed by both the Lepidium sativum L. germination test and the Collembola mortality test.

Anthraquinones↗
PubMed2004

Identification method based on PCR combined with automated ribotyping for tracking probiotic Lactobacillus strains colonizing the human gut and vagina.

AIMS: A molecular methodology based on PCR-associated automated ribotyping was developed to specifically detect the Lactobacillus strains of two probiotic products (an orally administered lyophilized preparation and vaginal tablets) in human faeces and vaginal swabs. METHODS AND RESULTS: The 16S-23S rDNA sequences and the ribotype profiles of the probiotic lactobacilli were characterized and new species-specific primer sets were designed. The identification of faecal and vaginal lactobacilli isolated from subjects administered with the probiotic products was performed by using PCR with species-specific primers followed by strain-specific automated ribotyping. CONCLUSIONS: The PCR-ribotyping identification allowed to study the colonization patterns of the probiotic lactobacilli in the human gut and vagina evidencing the strains with the best survival capability. SIGNIFICANCE AND IMPACT OF THE STUDY: The proposed molecular method represents a powerful tool of strain-specific identification, useful for differentiating exogenous from indigenous strains in any microbial ecosystem and for rationally choosing probiotic bacteria with the best chance of survival in the host.

Colony Count, Microbial↗
PubMed2004

The glucose oxidase of Penicillium variabile P16: gene cloning, sequencing and expression.

AIMS: Isolation and characterization of the glucose oxidase (GOX)-encoding gene from a Penicillium variabile strain (P16) having a high level of GOX activity and comparison of its expression with that of another strain of P. variabile (NRRL 1048) characterized by low GOX activity. METHODS AND RESULTS: The gene, isolated by PCR consisted of 1818 bp encoding 605 amino acid residues. Gene expression was analysed by Northern blotting and compared with that of P. variabile NRRL 1048. The higher GOX activity of strain P16 appeared likely because of de novo mRNA synthesis. Southern blotting analyses of the genomic DNA showed that the hybridization pattern of the two strains differed for the size of hybridizing fragment detected by the probe and slightly for their signal intensity. CONCLUSIONS: The GOX-encoding gene of P. variabile P16 was isolated and characterized to identify the molecular bases of its high level of expression and in view of improving enzyme production by developing a process based on heterologous expression. SIGNIFICANCE AND IMPACT OF THE STUDY: GOX-encoding genes can be subjected to high difference in their expression levels. The P16 strain of P. variable producing large amount of GOX as well as its encoding gene might be exploited for industrial applications.

Amino Acid Sequence↗
PubMed2001

Immobilized cell technology applied in solubilization of insoluble inorganic (rock) phosphates and P plant acquisition.

This paper reviews current knowledge of the production of organic acids by immobilized microorganisms with a simultaneous solubilization of rock phosphate in fermentation and soil conditions. The most widely applied methods are based on the passive immobilization in preformed porous carriers and entrapment of the microbial cells in natural gels. In general, immobilized systems show higher acid producing and rock phosphate solubilizing activity than freely suspended cells. The potential of gel-entrapped P-solubilizers and mycorrhizal fungi as microbial soil inoculants is also pointed out. Some advantages and constraints of using immobilized cells are discussed and a special emphasis on further research is given.

Cells, Immobilized↗
PubMed2001

The chitinolytic activity of Penicillium janthinellum P9: purification, partial characterization and potential applications.

AIMS: To purify and characterize the chitinolytic activity of Penicillium janthinellum P9 and to evaluate possible uses of the purified enzymes in the control of fungal growth and spore germination. METHODS AND RESULTS: The chitinolytic activity of P. janthinellum P9 was associated to two beta-N-acetyl-hexosaminidases (CHI1 and CHI2) that were purified by preparative isoelectric focusing and preparative electrophoresis and partially characterized. Treatment of test fungi with purified enzyme solutions caused reduced spore germination, reduction of hyphal length and mycelial damage. The combined action of the two enzymes and a systemic fungicide completely inactivated pests and food-spoiling moulds such as Fusarium solanii, P. canescens and Cladosporium cladosporioides. Treatment with the two enzymes increased germination of freeze-dried fungal spores. CONCLUSION: The chitinolytic activity of P. janthinellum P9 is associated with two extracellular beta-N-acetyl-hexosaminidases that can cause damage to the cell walls of other fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: This appears to be the first report on the characterization of extracellular chitinolytic enzymes produced by a Penicillium strain. The results of this study might have some impact in the applied research field.

Antifungal Agents↗
PubMed2001

Two-photon microscopy and spectroscopy based on a compact confocal scanning head.

We have combined a confocal laser scanning head modified for TPE (two-photon excitation) microscopy with some spectroscopic modules to study single molecules and molecular aggregates. The behavior of the TPE microscope unit has been characterized by means of point spread function measurements and of the demonstration of its micropatterning abilities. One-photon and two-photon mode can be simply accomplished by switching from a mono-mode optical fiber (one-photon) coupled to conventional laser sources to an optical module that allows IR laser beam (two-photon/TPE) delivery to the confocal laser scanning head. We have then described the characterization of the two-photon microscope for spectroscopic applications: fluorescence correlation, lifetime and fluorescence polarization anisotropy measurements. We describe the measurement of the response of the two-photon microscope to the light polarization and discuss fluorescence polarization anisotropy measurements on Rhodamine 6G as a function of the viscosity and on a globular protein, the Beta-lactoglobulin B labeled with Alexa 532 at very high dilutions. The average rotational and translational diffusion coefficients measured with fluorescence polarization anisotropy and fluorescence correlation methods are in good agreement with the protein size, therefore validating the use of the microscope for two-photon spectroscopy on biomolecules.

Animals↗
PubMed2000

Effect of pH and stirring rate on itaconate production by Aspergillus terreus.

The production of itaconic acid from glucose-based media by Aspergillus terreus NRRL 1960 was found to be controlled by stirring rate and pH. When the phosphorous (P) level in the production medium was reduced to less than 10 mg l(-1), the fungal mycelium exhausted its primary growth and started to excrete itaconic acid, while it continued its secondary growth at the expense of ammoniacal nitrogen. The fermentation exhibited a mixed-growth-associated product formation kinetics, the non-growth associated production term (mI) being practically zero only when the pH was left free to change from 3.4 down to 1.85. On the contrary, when the pH was kept reducing up to a constant value by automatic addition of KOH 4 mol l(-1), the itaconate yield coefficient on the initial glucose supplied (Y(I/So)) and mI and were 0.53 g g(-1) and 0.028 h(-1) at pH 2.4 and 320 rev min(-1) and 0.5 g g(-1) and 0.036 h(-1) at pH 2.8 and 400 rev min(-1), respectively. Although the differences between mI and Y(I/So) were statistically insignificant at the 95% confidence level, the net difference in the corresponding yield coefficients for itaconic acid on mycelial biomass resulted in a maximum itaconate production rate of 0.41 g l(-1) h(-1) at pH 2.8 and 400 rev min(-1), thus showing that this operating condition is no doubt optimal for the process under study.

Aspergillus↗
PubMed2000

Repeated-batch production of pigments by immobilised Monascus purpureus.

Extracellular pigment production by immobilised Monascus purpureus C322 has been studied in repeated-batch processes using different immobilising carriers such as Ca-alginate, polyurethane sponge, active carbon and pearlite. With Ca-alginate, pigment production was maximum (30.5 UA470 as process mean production, three batches) while the cell leakage was negligible (0.4 g 1(-1) free biomass) and the bead mechanical stability good; with this carrier, an extended repeated-batch fermentation (nine batches, 55 days) was carried out: the process pigment productivity was 3.87 UA470 day(-1).

Alginates↗
PubMed2000

Synthesis, X-ray powder structure, and magnetic properties of the new, weak ferromagnet iron(II) phenylphosphonate.

A new molecule-based weak ferromagnet of formula Fe[C6H5PO3].H2O was synthesized. It was characterized by thermogravimetric analysis and UV-visible and infrared spectroscopy, and the magnetic properties were studied using a superconducting quantum interference device magnetometer. The crystal structure of the compound was determined "ab initio" from X-ray powder diffraction data and refined by the Rietveld method. The crystals of Fe[C6H5PO3].H2O are orthorhombic, space group Pmn2(1), with a = 5.668(8) A, b = 14.453(2) A, c = 4.893(7) A, and Z = 2. The title compound is isostructural with the previously reported lamellar M[C6H5PO3].H2O, M = Mn(II), Zn(II), and Cd(II). The inorganic layers are made of Fe(II) ions octahedrally coordinated by five phosphonate oxygen atoms and one from oxygen of the water molecule. These layers are then separated by bilayers of the phenyl groups, and van der Waals contacts are established between them. The refinement has shown that the phenyl rings are disordered in the lattice. The oxidation state of the metal ion is +2, and the electronic configuration is d6 (S = 2) high-spin, as determined from dc magnetic susceptibility measurements from 150 K to room temperature. Below 100 K, the magnetic moment of Fe[C6H5PO3].H2O rises rapidly to a maximum at TN = 21.5 K, and then it decreases again. The peak at TN is associated with the 3D antiferromagnetic long-range ordering. Below the critical temperature, the title compound behaves as a "weak" ferromagnet, which represents the third type of magnetic materials characterized by having a finite zero-field magnetization, ferromagnets and ferrimagnets being the other two types. The large coercive field (i.e., 6400 G) observed in the hysteresis loop at T = 10 K is rare in molecule-based materials; it can be ascribed to a pronounced spin-orbit coupling for the 5T2g ground state of the Fe(II) ion in the octahedral environment.

Journal Article↗
PubMed2000

High-rate aerobic treatment of winery wastewater using bioreactors with free and immobilized activated sludge.

COD (chemical oxygen demand) removal rate and efficiency of winery wastewater (WW) aerobic treatments were evaluated in an air-bubble column bioreactor using self-adapted microbial populations either free or immobilized on polyurethane particles and in a packed-bed bioreactor immobilized on Raschig rings. The bioreactors were fed continuously for up to 12 months using WW of different origins and with different pollution loads (COD range, 0.8-11.0 kg.m(-3)): the maximum loading rate was approx. 8.8 kg-COD m(-3).d(-1). The highest COD removal rate (6.6 kg.m(-3).d(-1)) was obtained with free activated sludge in the bubble column bioreactor; treatment efficiency and hydraulic retention time were >90% and approx. 0.8 d, respectively. The microbial populations in the three reactors were characterized.

Journal Article↗
PubMed1999

Inactivation of Mucor plumbeus by the combined actions of chitinase and high hydrostatic pressure.

Sporangiospores were treated with high hydrostatic pressure and/or fungal chitinase in order to study the inhibition of germination and growth of the food spoiling mold Mucor plumbeus. Total fungal inhibition was obtained either at 4.0 kbar or by 10 U/ml of chitinase from Penicillium janthinellum. A pretreatment with 1 U/ml of the same chitinase reduced the pressure necessary to obtain complete spore inhibition to 3 kbar.

Chitinases↗
PubMed1999

Production and properties of the linamarase and amygdalase activities of Penicillium aurantiogriseum P35.

The effects of medium composition on the production of beta-glucosidase (amygdalase and linamarase) by Penicillium aurantiogriseum P35 were studied and the medium optimized as follows (g/l of deionized water): pectin, 10.0; (NH4)2SO4, 8.0; KH2PO4, 8.0; Na2HPO4, 2.8; MgSO4.7H2O, 0.5; yeast extract, 4.0; initial pH 6.0. When grown in a bench fermenter on this medium, the fungus produced 50.5 mU of amygdalase and 9.4 mU of linamarase per ml of culture broth. Two beta-glucosidases (PGI and PGII), each having amygdalase and linamarase activities, were recovered from the culture broth and purified; their relative molecular weights, as native enzymes, were estimated to be about 247,000 and 147,000, respectively. Both enzymes showed the same optimum pH (6.0) but different optimum temperatures (55 and 60 degrees C for PGI and PGII, respectively). Thermostability (10 min at 60 degrees C) and half-life of enzyme activity (7 hours at 60 degrees C) of PGII were higher than those of PGI (10 min at 50 degrees C and 2 hours at 55 degrees C, respectively). A wide range of cyanogenic glycosides (such as tetraphyllin B, epivolkenin, gynocardin, passibiflorin, prunasin, taxiphyllin, amygdalin, lucumin, sambunigrin, dhurrin, linamarin and cardiospermin sulfate) were hydrolyzed by both enzymes.

Bioreactors↗
PubMed1998

Amygdalin degradation by Mucor circinelloides and Penicillium aurantiogriseum: mechanisms of hydrolysis.

Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35 produce extracellular beta-glycosidases that are active on the cyanogenic glycoside amygdalin. From the culture broths of M. circinelloides, only one beta-glycosidase could be identified, while two different enzymes - both having amygdalase activity - were found in culture broths of P. aurantiogriseum. The study of the mechanism of hydrolysis of the beta-bis-glycoside amygdalin with purified enzymes from the two organisms indicated a possible sequential (two-step) reaction. In all cases, the first step of hydrolysis from amygdalin to prunasin was very rapid, while the second step from prunasin to cyanohydrin was much slower. No cyanohydrin lyase activity was found in the culture broths of either fungus.

Amygdalin↗
PubMed1998

Chitinolytic activity at low temperature of an Antarctic strain (A3) of Verticillium lecanii.

The chitinolytic activity of Verticillium cfr. lecanii A3, a strain isolated from continental Antarctica, was compared to those of two selected strains of Trichoderma harzianum. After 72 h of incubation at 25 degrees C in media containing chitin as the sole carbon source, all strains showed the same enzyme activity (ca. 230 mU/ml); at 15 degrees C, the levels of enzyme activity of the three strains were similar to those obtained at 25 degrees C. At 5 degrees C, in contrast, the activity of V. lecanii was ca. 4 times higher than those of both strains of T. harzianum (203 and 57 mU/ml, respectively; incubation time 144 h). The chitinase of V. lecanii, purified by preparative isoelectric focusing and ion-exchange chromatography, was shown to be a glycoprotein with apparent molecular weight of 45 kDa and isoelectric point of 4.9. The enzyme was active over a broad range of temperatures (5-60 degrees C): at 5 degrees C, its relative activity was still 50% of that recorded at 40 degrees C (optimal temperature). V. lecanii and its purified chitinase showed clear inhibitory effects on the growth of some test moulds such as Mucor plumbeus, Cladosporium cladosporioides, Aspergillus versicolor and Penicillium verrucosum: observations under the light and scanning electron microscopes revealed that growth inhibition was accompanied by mycelial damage and cell lysis.

Antarctic Regions↗
PubMed1996

Two-step hydrolysis of amygdalin in molds.

Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35, characterized by extracellular beta-glucosidase activity on cyanogenic glycosides, hydrolyse amygdalin by a two-step reaction mechanism being the first step of hydrolysis, from amygdalin to prunasin, very rapid (15 min) and the second one, from prunasin to mandelonitrile, much slower (120 min).

Acetonitriles↗
PubMed1993

2,2'-Bipyridyl-6-carbothioamide and its ferrous complex: their in vitro antitumoral activity related to the inhibition of ribonucleotide reductase R2 subunit.

2,2'-Bipyridyl-6-carbothioamide (BPYTA), a synthetic compound with antitumoral activity, is characterized by chelating properties because of the N*-N*-S* tridentate ligand system and is therefore comparable to alpha-(N)-heterocyclic carboxaldehyde thiosemicarbazones which are potent inhibitors of ribonucleotide reductase (RR). Electron paramagnetic resonance studies on the small subunit of mouse recombinant RR (R2) demonstrated that BPYTA can destroy the R2 tyrosyl radical only if Fe(II) is present (73% destruction at 50 microM, after 20 min of contact). The R2 inhibition was reversible and time dependent. Studies on tumoral lines confirmed that the main cell target of BPYTA is RR and demonstrated that the iron-complexed form compared to the nonchelated form has some difficulty in crossing the cell membrane. Spectrophotometric and electron paramagnetic resonance studies clearly indicated that BPYTA chelates iron only when this is reduced and that the BPYTA-Fe(II) complex is stable in the presence of oxygen. From reported results we conclude that BPYTA is a powerful RR inhibitor (R2 subunit) which has a different mechanism of action from that of Desferal. It has some properties in common with alpha-(N)-heterocyclic carboxaldehyde thiosemicarbazones, but they are not identical. It would be interesting to do further studies on the BPYTA mechanism of action and evaluate the in vivo antitumoral activity of the preformed complex.

2,2'-Dipyridyl↗