Donatella Paffetti | Università degli Studi di Firenze (University of Florence) (original) (raw)

Papers by Donatella Paffetti

Research paper thumbnail of Evaluating impact of possible transgenic poplar cultivation on protected areas

Research paper thumbnail of The influence of forest management on beech (Fagus sylvatica L.) stand structure and genetic diversity

Forest Ecology and Management, 2012

© iForest -Biogeosciences and Forestry © SISEF http://www.sisef.it/iforest/ 105 iForest (2009) 2:... more © iForest -Biogeosciences and Forestry © SISEF http://www.sisef.it/iforest/ 105 iForest (2009) 2: 105-113 Citation: Nocentini S, 2009. Structure and management of beech (Fagus sylvatica L.) forests in Italy. iForest 0: 0-0 [online 2009. Structure and management of beech (Fagus sylvatica L.) forests in Italy. iForest 2: 105-113 [online: 2009-06-10] URL: http://www.sisef.it/iforest/show.php? id=499 Collection: COST Action E52 Meeting 2008 -Florence (Italy) Evaluation of beech genetic resources for sustainable forestry Guest Editors: Georg von Wühlisch, Raffaello Giannini Structure and management of beech (Fagus sylvatica L.) forests in Italy Nocentini S

Research paper thumbnail of Characterization, structure and genetic dating of an old-growth beech-fir forest in the northern Apennines (Italy)

Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2012

Research paper thumbnail of Pollen flow evaluation to implement a Quick Monitoring Index (QMI)

Research paper thumbnail of Identification and molecular characterization of LTR and LINE retrotransposable elements in Fagus sylvatica L

Iforest - Biogeosciences and Forestry, 2009

Research paper thumbnail of Influence of plant genotype on the selection of nodulating Sinorhizobium meliloti strains by Medicago sativa

Antonie van Leeuwenhoek, 1998

We analysed the genetic diversity of 270 Sinorhizobium meliloti strains isolated from nodules of ... more We analysed the genetic diversity of 270 Sinorhizobium meliloti strains isolated from nodules of three different Medicago sativa varieties, planted in three different Italian soils, combining the Analysis of Molecular Variance (AMOVA) with the Random Amplified Polymorphic DNA (RAPD) technique to estimate variance among RAPD patterns with the aim to draw an objective description of the population genetic structure. Results indicated that a general intraspecific genetic diversity was globally distributed among all the population, however a very high level of diversity was found among strains nodulating different Medicago sativa varieties. Moreover the distribution of the RAPD haplotypes among the plant varieties also showed to be non-random. The overall data indicated that the plant genotype is a major factor in shaping the genetic structure of this natural Rhizobium population.

Research paper thumbnail of Biodiversity of a Burkholderia cepacia population isolated from the maize rhizosphere at different plant growth stages

Applied and environmental microbiology, 1997

A Burkholderia cepacia population naturally occurring in the rhizosphere of Zea mays was investig... more A Burkholderia cepacia population naturally occurring in the rhizosphere of Zea mays was investigated in order to assess the degree of root association and microbial biodiversity at five stages of plant growth. The bacterial strains isolated on semiselective PCAT medium were mostly assigned to the species B. cepacia by an analysis of the restriction patterns produced by amplified DNA coding for 16S rRNA (16S rDNA) (ARDRA) with the enzyme AluI. Partial 16S rDNA nucleotide sequences of some randomly chosen isolates confirmed the ARDRA results. Throughout the study, B. cepacia was strictly associated with maize roots, ranging from 0.6 to 3.6% of the total cultivable microflora. Biodiversity among 83 B. cepacia isolates was analyzed by the random amplified polymorphic DNA (RAPD) technique with two 10-mer primers. An analysis of RAPD patterns by the analysis of molecular variance method revealed a high level of intraspecific genetic diversity in this B. cepacia population. Moreover, the ...

Research paper thumbnail of Persistence of toxins and cells of Bacillus thuringiensis subsp. kurstaki introduced in sprays to Sardinia soils

Soil Biology and Biochemistry, 2003

Sprays of commercial insecticidal preparations of the bacterium, Bacillus thuringiensis subsp. ku... more Sprays of commercial insecticidal preparations of the bacterium, Bacillus thuringiensis subsp. kurstaki (Btk), usually a mixture of cells, spores and parasporal crystals, have been used for the last 10 yr in Sardinia (Italy) to protect cork oak forests against the gypsy moth (Lymantria dispar L.). Until now, the protective antilepidopteran efficacies of each of the various spray treatments rather than their effects on the environment have been evaluated. Consequently, the persistence of Btk and its toxin, released in sprays (FORAY 48B w ), in soils of cork oak stands, located in Orotelli, Tempio Pausania and Calangianus (Sardinia), were investigated. In the Calangianus soil, the numbers of Btk remained essentially constant for 28 months (the longest time studied) after spraying, indicating that Btk was able to compete with the indigenous microbial community; the toxin was detected 28 months after spraying by immunological assay, but at a reduced concentration; and the larvicidal activity decreased essentially linearly to 14 months and then decreased markedly between 14 and 28 months. In the Tempio Pausania and Orotelli soils, cells of Btk were detected, whereas the toxin was not detected by immunological and larvicidal assays, 52 and 88 months (the longest times studied) after spraying, respectively. The numbers of Btk cells detected were probably too low to account for the presence of the toxin in all of the soils studied, as there was no correlation between numbers of Btk and toxin detected by immunological assays (correlation coefficient of 20.66) in the Calangianus soil. Our results indicated that Btk and its toxin introduced into soils in sprays can persist for long periods (at least 88 months for Btk and at least 28 months for its toxin). q

Research paper thumbnail of Indagini preliminari sulla variabilità genetica della beccaccia (Scolopax rusticola L.)

L'Italia Forestale e Montana, 2007

L'uso di marcatori molecolari su individui di Beccaccia offre la possibilità di evidenziare event... more L'uso di marcatori molecolari su individui di Beccaccia offre la possibilità di evidenziare eventuali gradi di parentela e, quindi, di avviare nuove pratiche di gestione. Mediante i marcatori RAPD e l'analisi di sequenze di zone non codificanti mitocondriali (mtDNA) su campioni prelevati in varie località italiane, gli autori hanno definito un quadro attendibile della variabilità genetica della specie, sia a livello di popolazione, sia di individui. Le sequenze di mtDNA hanno mostrato, tra l'altro, la diversa distribuzione degli aplotipi nelle località esaminate. Palazzuolo sul Senio (FI) è risultata quella con la minore presenza di aplotipi, a conferma di come le modifiche ambientali abbiano reso quest'area poco adatta alla sosta dello scolopacide. I marcatori RAPD, eseguiti solo sugli individui prelevati nelle località toscane, hanno fornito risultati che confermano le ipotesi che il volo migratorio delle beccacce venga realizzato da popolazioni geneticamente molto simili. Parole chiave: Caradriiformi; Scolopax; Beccaccia, RAPD; mtDNA.

Research paper thumbnail of Geographic distribution of genetic variability of Fagus sylvatica L. in southern Italian populations

Forest Genetics, 2004

... Giannnini, Institute of Plant Genetics, National Research Council, via Madonna del Piano, 1-5... more ... Giannnini, Institute of Plant Genetics, National Research Council, via Madonna del Piano, 1-50019 Sesto Fiorentino, Florence, Italy. ... Foresta Umbra (Vieste, FG) Monte Mauro (Castelmauro, CB) La Montagnola (Civitanova del Sannio, CB) Campitello Matese (S. Massimo, CB ...

Research paper thumbnail of Geographic distribution of chloroplast variation in Italian populations of beech ( Fagus sylvatica L.)

TAG Theoretical and Applied Genetics, 2004

The distribution of chloroplast DNA (cpDNA) variation in Italian beech ( Fagus sylvatica L.) popu... more The distribution of chloroplast DNA (cpDNA) variation in Italian beech ( Fagus sylvatica L.) populations was studied using PCR-RFLP and microsatellite markers. In total, 67 populations were analysed, and 14 haplotypes were identified by combining the two marker types. A remarkable subdivision of cpDNA diversity in Italian beech was found, as indicated by a high level of genetic differentiation ( G(st)=0.855). The highest level of total haplotype diversity ( h(t)=0.822) was estimated for southern Italian populations. The highest number of haplotypes was found in the central-southern region of the peninsula. The nested clade analysis provided evidence for past fragmentation events that may have been occurred during the Quaternary glaciations and had a major role in defining the genetic structure of the central-southern Italian beech populations. Only one haplotype apparently spread towards the north of Italy along the Apennine chain and reached the Italian slope of the western part of the Alps (Maritime Alps, Liguria). All haplotypes found along the Apennines remained trapped in the Italian peninsula. Southern and central Italy represent hotspots of haplotype diversity for Italian beech.

Research paper thumbnail of Characterization, structure and genetic dating of an old-growth beech-fir forest in the northern Apennines (Italy)

Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2012

Research paper thumbnail of Directed evolution experiments in histidine biosynthesis

Origins of Life and Evolution of the Biosphere, 1996

Research paper thumbnail of European discussion forum on transgenic tree biosafety

Nature Biotechnology, 2012

Research paper thumbnail of Different gene expression pattern of Populus alba L. genotypes under elevated UV-B radiation

Journal of Biotechnology, 2010

Research paper thumbnail of Genetic variation in Heterobasidion abietinum populations detected with the M13 minisatellite marker

Forest Pathology, 2007

Amplification profiles of the M13 minisatellite core sequence from 47 isolates of Heterobasidion ... more Amplification profiles of the M13 minisatellite core sequence from 47 isolates of Heterobasidion annosum s.l., collected mostly from Abies alba in different European countries, were analysed in comparison with profiles of four isolates of H. annosum s.s. and three isolates of H. parviporum. Genetic variation within and among groups of populations was studied by analysis of molecular variance. A dendrogram constructed with the Neighbor-Joining method differentiated the three species from each other. Isolates of H. abietinum from Balkan peninsula, Italian peninsula and French Pyrenees each separated into clusters according to geographical origin. Such clear geographic clustering was not detected among isolates from central Europe. The variations between H. abietinum isolates in relation to the migration history of Abies are discussed.

Research paper thumbnail of Genetic variation of Heterobasidion abietinum in Southern Europe and the Mediterranean Basin

Forest Pathology, 2011

Heterobasidion abietinum causes root and butt rot on Abies species occurring in central Europe an... more Heterobasidion abietinum causes root and butt rot on Abies species occurring in central Europe and the Mediterranean Basin in a distribution extending from Spain in the west to Turkey and Caucasia in the east. To investigate the genetic diversity within H. abietinum, 95 isolates from different regions were analysed with 61 polymorphic molecular markers. The markers showed genetic differentiation amongst the H. abietinum populations. The most diversified population is that on A. pinsapo in southern Spain, which is isolated from gene flow with other populations. Lower but still significant differences were found amongst other European populations. Isolates from Turkey showed little diversification compared with the south European isolates from east of the Alps. The genetic structure of the H. abietinum populations in relation to postglacial recolonization of Abies is discussed.

Research paper thumbnail of Factors affecting nitrogen fixation and nif gene transcription in Azospirillum brasilense

FEMS Microbiology Letters, 1994

The effect of environmental factors on nitrogenase activity and on transcription of nif genes in ... more The effect of environmental factors on nitrogenase activity and on transcription of nif genes in Azospirillum brasilense was investigated. Addition of ammonium, glutamine, oxygen, nitrate or nitrite together with either iron limitation or shift of temperature caused different levels of inhibition of nitrogenase activity. The nil mRNA was completely absent after addition of either ammonium or glutamine and after iron deprivation, while oxygen, nitrate or nitrite partially decreased the presence of nif mRNA. It is concluded that in A. brasilense the control of the nitrogenase switch-off is independent of the transcription of nif genes.

Research paper thumbnail of Amplification of bacterial DNA bound on clay minerals by the random amplified polymorphic DNA (RAPD) technique

Chromosomal DNA from 3ucilfus S&~&S, bound on the clay minerals, montmorillonite (Wyoming (W) and... more Chromosomal DNA from 3ucilfus S&~&S, bound on the clay minerals, montmorillonite (Wyoming (W) and Apache County (Ap)) and kaolinite (RI, was subjected to the random amplified polymorphic DNA (RAPD) technique. DNA bound on the clays was not amplified with 0.625, 1.875, 6.25, and 12.5 U of Tuq DNA polymerase, but amplification occurred when the clay-DNA complexes were diluted IO-and 20-fold or when 21 U of Taq DNA polymerase was added. DNA desorbed from the Ap-DNA and K-DNA equilibrium complexes was amplified with 0.625 U of Taq DNA polymerase, whereas amplification of DNA desorbed from the W-DNA complex occurred only after a IO-fold dilution or when 1.875 U of Tuq DNA polymerase was used. These observations indicate that clay minerals differentially affect the amplification process, probably by inhibiting the activity of Taq DNA polymerase.

Research paper thumbnail of Unexpected presence of Fagus orientalis complex in Italy as inferred from 45,000-year-old DNA pollen samples from Venice lagoon

BMC Evolutionary Biology, 2007

Background: Phylogeographic analyses on the Western Euroasiatic Fagus taxa (F. orientalis, F. syl... more Background: Phylogeographic analyses on the Western Euroasiatic Fagus taxa (F. orientalis, F. sylvatica, F. taurica and F. moesiaca) is available, however, the subdivision of Fagus spp. is unresolved and there is no consensus on the phylogeny and on the identification (both with morphological than molecular markers) of Fagus Eurasiatic taxa.

Research paper thumbnail of Evaluating impact of possible transgenic poplar cultivation on protected areas

Research paper thumbnail of The influence of forest management on beech (Fagus sylvatica L.) stand structure and genetic diversity

Forest Ecology and Management, 2012

© iForest -Biogeosciences and Forestry © SISEF http://www.sisef.it/iforest/ 105 iForest (2009) 2:... more © iForest -Biogeosciences and Forestry © SISEF http://www.sisef.it/iforest/ 105 iForest (2009) 2: 105-113 Citation: Nocentini S, 2009. Structure and management of beech (Fagus sylvatica L.) forests in Italy. iForest 0: 0-0 [online 2009. Structure and management of beech (Fagus sylvatica L.) forests in Italy. iForest 2: 105-113 [online: 2009-06-10] URL: http://www.sisef.it/iforest/show.php? id=499 Collection: COST Action E52 Meeting 2008 -Florence (Italy) Evaluation of beech genetic resources for sustainable forestry Guest Editors: Georg von Wühlisch, Raffaello Giannini Structure and management of beech (Fagus sylvatica L.) forests in Italy Nocentini S

Research paper thumbnail of Characterization, structure and genetic dating of an old-growth beech-fir forest in the northern Apennines (Italy)

Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2012

Research paper thumbnail of Pollen flow evaluation to implement a Quick Monitoring Index (QMI)

Research paper thumbnail of Identification and molecular characterization of LTR and LINE retrotransposable elements in Fagus sylvatica L

Iforest - Biogeosciences and Forestry, 2009

Research paper thumbnail of Influence of plant genotype on the selection of nodulating Sinorhizobium meliloti strains by Medicago sativa

Antonie van Leeuwenhoek, 1998

We analysed the genetic diversity of 270 Sinorhizobium meliloti strains isolated from nodules of ... more We analysed the genetic diversity of 270 Sinorhizobium meliloti strains isolated from nodules of three different Medicago sativa varieties, planted in three different Italian soils, combining the Analysis of Molecular Variance (AMOVA) with the Random Amplified Polymorphic DNA (RAPD) technique to estimate variance among RAPD patterns with the aim to draw an objective description of the population genetic structure. Results indicated that a general intraspecific genetic diversity was globally distributed among all the population, however a very high level of diversity was found among strains nodulating different Medicago sativa varieties. Moreover the distribution of the RAPD haplotypes among the plant varieties also showed to be non-random. The overall data indicated that the plant genotype is a major factor in shaping the genetic structure of this natural Rhizobium population.

Research paper thumbnail of Biodiversity of a Burkholderia cepacia population isolated from the maize rhizosphere at different plant growth stages

Applied and environmental microbiology, 1997

A Burkholderia cepacia population naturally occurring in the rhizosphere of Zea mays was investig... more A Burkholderia cepacia population naturally occurring in the rhizosphere of Zea mays was investigated in order to assess the degree of root association and microbial biodiversity at five stages of plant growth. The bacterial strains isolated on semiselective PCAT medium were mostly assigned to the species B. cepacia by an analysis of the restriction patterns produced by amplified DNA coding for 16S rRNA (16S rDNA) (ARDRA) with the enzyme AluI. Partial 16S rDNA nucleotide sequences of some randomly chosen isolates confirmed the ARDRA results. Throughout the study, B. cepacia was strictly associated with maize roots, ranging from 0.6 to 3.6% of the total cultivable microflora. Biodiversity among 83 B. cepacia isolates was analyzed by the random amplified polymorphic DNA (RAPD) technique with two 10-mer primers. An analysis of RAPD patterns by the analysis of molecular variance method revealed a high level of intraspecific genetic diversity in this B. cepacia population. Moreover, the ...

Research paper thumbnail of Persistence of toxins and cells of Bacillus thuringiensis subsp. kurstaki introduced in sprays to Sardinia soils

Soil Biology and Biochemistry, 2003

Sprays of commercial insecticidal preparations of the bacterium, Bacillus thuringiensis subsp. ku... more Sprays of commercial insecticidal preparations of the bacterium, Bacillus thuringiensis subsp. kurstaki (Btk), usually a mixture of cells, spores and parasporal crystals, have been used for the last 10 yr in Sardinia (Italy) to protect cork oak forests against the gypsy moth (Lymantria dispar L.). Until now, the protective antilepidopteran efficacies of each of the various spray treatments rather than their effects on the environment have been evaluated. Consequently, the persistence of Btk and its toxin, released in sprays (FORAY 48B w ), in soils of cork oak stands, located in Orotelli, Tempio Pausania and Calangianus (Sardinia), were investigated. In the Calangianus soil, the numbers of Btk remained essentially constant for 28 months (the longest time studied) after spraying, indicating that Btk was able to compete with the indigenous microbial community; the toxin was detected 28 months after spraying by immunological assay, but at a reduced concentration; and the larvicidal activity decreased essentially linearly to 14 months and then decreased markedly between 14 and 28 months. In the Tempio Pausania and Orotelli soils, cells of Btk were detected, whereas the toxin was not detected by immunological and larvicidal assays, 52 and 88 months (the longest times studied) after spraying, respectively. The numbers of Btk cells detected were probably too low to account for the presence of the toxin in all of the soils studied, as there was no correlation between numbers of Btk and toxin detected by immunological assays (correlation coefficient of 20.66) in the Calangianus soil. Our results indicated that Btk and its toxin introduced into soils in sprays can persist for long periods (at least 88 months for Btk and at least 28 months for its toxin). q

Research paper thumbnail of Indagini preliminari sulla variabilità genetica della beccaccia (Scolopax rusticola L.)

L'Italia Forestale e Montana, 2007

L'uso di marcatori molecolari su individui di Beccaccia offre la possibilità di evidenziare event... more L'uso di marcatori molecolari su individui di Beccaccia offre la possibilità di evidenziare eventuali gradi di parentela e, quindi, di avviare nuove pratiche di gestione. Mediante i marcatori RAPD e l'analisi di sequenze di zone non codificanti mitocondriali (mtDNA) su campioni prelevati in varie località italiane, gli autori hanno definito un quadro attendibile della variabilità genetica della specie, sia a livello di popolazione, sia di individui. Le sequenze di mtDNA hanno mostrato, tra l'altro, la diversa distribuzione degli aplotipi nelle località esaminate. Palazzuolo sul Senio (FI) è risultata quella con la minore presenza di aplotipi, a conferma di come le modifiche ambientali abbiano reso quest'area poco adatta alla sosta dello scolopacide. I marcatori RAPD, eseguiti solo sugli individui prelevati nelle località toscane, hanno fornito risultati che confermano le ipotesi che il volo migratorio delle beccacce venga realizzato da popolazioni geneticamente molto simili. Parole chiave: Caradriiformi; Scolopax; Beccaccia, RAPD; mtDNA.

Research paper thumbnail of Geographic distribution of genetic variability of Fagus sylvatica L. in southern Italian populations

Forest Genetics, 2004

... Giannnini, Institute of Plant Genetics, National Research Council, via Madonna del Piano, 1-5... more ... Giannnini, Institute of Plant Genetics, National Research Council, via Madonna del Piano, 1-50019 Sesto Fiorentino, Florence, Italy. ... Foresta Umbra (Vieste, FG) Monte Mauro (Castelmauro, CB) La Montagnola (Civitanova del Sannio, CB) Campitello Matese (S. Massimo, CB ...

Research paper thumbnail of Geographic distribution of chloroplast variation in Italian populations of beech ( Fagus sylvatica L.)

TAG Theoretical and Applied Genetics, 2004

The distribution of chloroplast DNA (cpDNA) variation in Italian beech ( Fagus sylvatica L.) popu... more The distribution of chloroplast DNA (cpDNA) variation in Italian beech ( Fagus sylvatica L.) populations was studied using PCR-RFLP and microsatellite markers. In total, 67 populations were analysed, and 14 haplotypes were identified by combining the two marker types. A remarkable subdivision of cpDNA diversity in Italian beech was found, as indicated by a high level of genetic differentiation ( G(st)=0.855). The highest level of total haplotype diversity ( h(t)=0.822) was estimated for southern Italian populations. The highest number of haplotypes was found in the central-southern region of the peninsula. The nested clade analysis provided evidence for past fragmentation events that may have been occurred during the Quaternary glaciations and had a major role in defining the genetic structure of the central-southern Italian beech populations. Only one haplotype apparently spread towards the north of Italy along the Apennine chain and reached the Italian slope of the western part of the Alps (Maritime Alps, Liguria). All haplotypes found along the Apennines remained trapped in the Italian peninsula. Southern and central Italy represent hotspots of haplotype diversity for Italian beech.

Research paper thumbnail of Characterization, structure and genetic dating of an old-growth beech-fir forest in the northern Apennines (Italy)

Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2012

Research paper thumbnail of Directed evolution experiments in histidine biosynthesis

Origins of Life and Evolution of the Biosphere, 1996

Research paper thumbnail of European discussion forum on transgenic tree biosafety

Nature Biotechnology, 2012

Research paper thumbnail of Different gene expression pattern of Populus alba L. genotypes under elevated UV-B radiation

Journal of Biotechnology, 2010

Research paper thumbnail of Genetic variation in Heterobasidion abietinum populations detected with the M13 minisatellite marker

Forest Pathology, 2007

Amplification profiles of the M13 minisatellite core sequence from 47 isolates of Heterobasidion ... more Amplification profiles of the M13 minisatellite core sequence from 47 isolates of Heterobasidion annosum s.l., collected mostly from Abies alba in different European countries, were analysed in comparison with profiles of four isolates of H. annosum s.s. and three isolates of H. parviporum. Genetic variation within and among groups of populations was studied by analysis of molecular variance. A dendrogram constructed with the Neighbor-Joining method differentiated the three species from each other. Isolates of H. abietinum from Balkan peninsula, Italian peninsula and French Pyrenees each separated into clusters according to geographical origin. Such clear geographic clustering was not detected among isolates from central Europe. The variations between H. abietinum isolates in relation to the migration history of Abies are discussed.

Research paper thumbnail of Genetic variation of Heterobasidion abietinum in Southern Europe and the Mediterranean Basin

Forest Pathology, 2011

Heterobasidion abietinum causes root and butt rot on Abies species occurring in central Europe an... more Heterobasidion abietinum causes root and butt rot on Abies species occurring in central Europe and the Mediterranean Basin in a distribution extending from Spain in the west to Turkey and Caucasia in the east. To investigate the genetic diversity within H. abietinum, 95 isolates from different regions were analysed with 61 polymorphic molecular markers. The markers showed genetic differentiation amongst the H. abietinum populations. The most diversified population is that on A. pinsapo in southern Spain, which is isolated from gene flow with other populations. Lower but still significant differences were found amongst other European populations. Isolates from Turkey showed little diversification compared with the south European isolates from east of the Alps. The genetic structure of the H. abietinum populations in relation to postglacial recolonization of Abies is discussed.

Research paper thumbnail of Factors affecting nitrogen fixation and nif gene transcription in Azospirillum brasilense

FEMS Microbiology Letters, 1994

The effect of environmental factors on nitrogenase activity and on transcription of nif genes in ... more The effect of environmental factors on nitrogenase activity and on transcription of nif genes in Azospirillum brasilense was investigated. Addition of ammonium, glutamine, oxygen, nitrate or nitrite together with either iron limitation or shift of temperature caused different levels of inhibition of nitrogenase activity. The nil mRNA was completely absent after addition of either ammonium or glutamine and after iron deprivation, while oxygen, nitrate or nitrite partially decreased the presence of nif mRNA. It is concluded that in A. brasilense the control of the nitrogenase switch-off is independent of the transcription of nif genes.

Research paper thumbnail of Amplification of bacterial DNA bound on clay minerals by the random amplified polymorphic DNA (RAPD) technique

Chromosomal DNA from 3ucilfus S&~&S, bound on the clay minerals, montmorillonite (Wyoming (W) and... more Chromosomal DNA from 3ucilfus S&~&S, bound on the clay minerals, montmorillonite (Wyoming (W) and Apache County (Ap)) and kaolinite (RI, was subjected to the random amplified polymorphic DNA (RAPD) technique. DNA bound on the clays was not amplified with 0.625, 1.875, 6.25, and 12.5 U of Tuq DNA polymerase, but amplification occurred when the clay-DNA complexes were diluted IO-and 20-fold or when 21 U of Taq DNA polymerase was added. DNA desorbed from the Ap-DNA and K-DNA equilibrium complexes was amplified with 0.625 U of Taq DNA polymerase, whereas amplification of DNA desorbed from the W-DNA complex occurred only after a IO-fold dilution or when 1.875 U of Tuq DNA polymerase was used. These observations indicate that clay minerals differentially affect the amplification process, probably by inhibiting the activity of Taq DNA polymerase.

Research paper thumbnail of Unexpected presence of Fagus orientalis complex in Italy as inferred from 45,000-year-old DNA pollen samples from Venice lagoon

BMC Evolutionary Biology, 2007

Background: Phylogeographic analyses on the Western Euroasiatic Fagus taxa (F. orientalis, F. syl... more Background: Phylogeographic analyses on the Western Euroasiatic Fagus taxa (F. orientalis, F. sylvatica, F. taurica and F. moesiaca) is available, however, the subdivision of Fagus spp. is unresolved and there is no consensus on the phylogeny and on the identification (both with morphological than molecular markers) of Fagus Eurasiatic taxa.