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S Rossetti

Publications and source records attributed to S Rossetti.

At least 19 recordsLinked to original sources
PubMed2006

RAR-mediated epigenetic control of the cytochrome P450 Cyp26a1 in embryocarcinoma cells.

Retinoic acid (RA) is a signaling molecule that plays a pivotal role in major cellular processes and vertebrate development. RA action is mediated by specialized transcription factors, the nuclear RA receptors (RARs), which regulate the transcription of genes containing a RA-responsive element (RARE). Here we demonstrate that the genes for the RA-receptor RARbeta2 and the cytochrome P450 RA-specific hydrolase Cyp26a1 involved in RA catabolism are coordinately regulated by RA. We found that both RARbeta2 and Cyp26a1 genes are epigenetically silenced in the absence of DNA methylation in RAC65, a P19 embryocarcinoma cell line derivative carrying a dominant-negative RARalpha mutant and resistant to the growth-inhibitory and differentiation effects of RA. In response to RA, RARbeta2 transcription is epigenetically regulated by RARalpha. Similarly, we found that Cyp26a1 transcription is epigenetically regulated by RARbeta2. Knocking down RARbeta2 transcription by RNA interference in wild-type P19 cells, with an intact RARalpha, induced Cyp26a1 transcriptional repression in the absence of DNA methylation. Concomitantly, cells developed RA resistance and did not undergo RA-induced neuron differentiation. Apparently, RARalpha, RARbeta2 and Cyp26a1 are components of a RA-regulated gene network. Factors affecting an upstream gene of the network can trigger repressive chromatin changes -- which are propagated in a domino fashion - at downstream genes of the network. This study also shows that chromatin inactivity, and consequent transcriptional silencing, can be achieved in the absence of DNA methylation.

Animals↗
PubMed2006

Optical and mechanical shrinkage effects in dye-doped photonic bandgap structures based on organic materials.

In this work we study the effects of the optical shrinkage in polymer and liquid crystal (LC) mixtures optimized for their use as active media in compact plastic laser devices. These mixtures are characterized by the presence of the rhodamine 6G as an active dye. Modifications in the reflection properties of the gratings as a function of the active dye concentration have been determined experimentally and a detailed theoretical simulation of the optical transmittance properties of these devices is provided. Moreover, the comparison between two different experimental approaches clarifies the contribution to the optical shrinkage due to the presence of the active dye. In principle this approach allows determining the linear mechanical shrinkage by separating the contribution to optical shrinkage due to photochemical transformations from that due to mechanical effects.

Journal Article↗
PubMed2006

Description of filamentous bacteria present in industrial activated sludge WWTPs by conventional and molecular methods.

Conventional cultivation methods and molecular approaches were utilised to describe the filamentous bacterial population of industrial activated sludge WWTPs. In total 43 strains were isolated by micromanipulation and were affiliated with 12 different species, comprising two new species and a new genus. In particular, a new species of Microthrix, a new genus of a filamentous Alphaproteobacteria morphologically similar to Nostocoida limicola, and a new filamentous species closely related to the opportunistic pathogen Propionibacterium propionicum were obtained. Despite the high number of isolates, the cultivation approach was unable to describe the filamentous bacteria most common in industrial WWTP. A culture-independent approach, termed the cell sorting/RT-PCR method, was therefore applied to identify fastidious or non-culturable filamentous microrganisms from different industrial plants. By this method the relevant filaments were micromanipulated and their 16S rDNA genes were amplified by RT-PCR. This approach was highly efficient. In total 31 16S rRNA sequences were obtained and 16 of them were used for the design of new specific oligonucleotide probes that highlighted dominant filaments in industrial activated sludge plants.

Bacteria↗
PubMed2006

Microbial community analysis with a high PHA storage capacity.

Activated sludge was submitted to aerobic dynamic substrate feeding for the production of biodegradable plastics. Two sequencing batch reactors were operated with acetate or propionate as sole carbon substrates. With acetate a homopolymer of polyhydroxybutyrate (PHB) was obtained and with propionate a copolymer of hydroxybutyrate and hydroxyvalerate P(HB/HV) was produced. Three main morphotypes were identified in both sludges: two belong to the Alphaproteobacteria class and the third to the Betaproteobacteria class. Bacilli belonging to Betaproteobacteria were shown by FISH analysis, applied in combination with Nile Blue post-staining, to be the main responsible for PHAs storage. The latter were affiliated to Azoarcus genus within Betaproteobacteria.

Alkanes↗
PubMed2006

Simultaneous biological removal of sulphide and nitrate by autotrophic denitrification in an activated sludge system.

The feasibility of an autotrophic denitrification process in an activated sludge reactor, using sulphide as the electron donor, was tested for simultaneous denitrification and sulphide removal. The reactor was operated at nitrate (N) to sulphide (S) ratios between 0.5 and 0.9 to evaluate their effect on the N-removal efficiency, the S-removal efficiency and the product formation during anoxic oxidation of sulphide. One hundred per cent removal of both nitrate and sulphide was achieved at a NLR of 7.96 mmol N-L(-1) x d(-1) (111.44 mg NO3- -N x L(-1) x d(-1)) and at a N/S ratio of 0.89 with complete oxidation of sulphide to sulphate. The oxygen level in the reactor (10%) was found to influence the N-removal efficiency by inhibiting the denitrification process. Moreover, chemical (or biological) oxidation of sulphide with oxygen occurred, resulting in a loss of the electron donor. FISH analysis was carried out to study the microbial population in the system.

Nitrates↗
PubMed2005

Anaerobic transformation of tetrachloroethane, perchloroethylene, and their mixtures by mixed-cultures enriched from contaminated soils and sediments.

The focus of this research was to investigate the anaerobic transformation of tetrachloroethane (TeCA), perchloroethylene (PCE), and their mixtures by mixed cultures enriched from contaminated soils or sediments. Batch transformation studies were conducted using TeCA (60 microM), PCE (60 microM), or TeCA + PCE (each added at 60 microM) as electron acceptor(s) and H2 + acetate (each added at 3 mM) or butyrate (3mM) as electron donor(s). A Dehalococcoides spp.-containing, sediment-enrichment dechlorinated PCE rapidly to ethene (ETH) but slowly and incompletely dechlorinated TeCA. Moreover, when present in mixture with PCE, TeCA disrupted the ability of Dehalococcoides to dechlorinate vinyl chloride. In contrast, the soil-enrichment culture was able to completely dechlorinate TeCA and PCE to ETH, both when added as single contaminants and when added as a mixture.

Acetates↗
PubMed2004

Caroli's disease: prenatal diagnosis, postnatal outcome and genetic analysis.

Caroli's disease is a rare autosomal recessive condition characterized by cystic dilatation of the intrahepatic bile ducts and infantile polycystic kidney disease. We report a case with Caroli's disease detected prenatally at 33 weeks' gestation with fetal ultrasound findings of a cystic liver mass and echogenic kidneys. Postnatal investigation confirmed enlarged and echogenic kidneys with dilatation of the intrahepatic bile ducts consistent with the diagnosis of Caroli's disease. Genetic analysis of the gene, PKHD1, associated with autosomal recessive polycystic kidney disease (ARPKD) showed that the patient had compound heterozygous mutations, confirming that this early onset Caroli's disease was part of the spectrum of ARPKD. To our knowledge this is the third case of Caroli's disease detected prenatally and the first in which the infant survived.

Caroli Disease↗
PubMed2004

The use of the anti-tumour necrosis factor monoclonal antibody--infliximab--to treat ulcerative colitis: implications and trends beyond the available data.

The monoclonal antibody to the tumour necrosis factor--infliximab--has recently been added to the list of off-label therapeutic means for ulcerative colitis. We conducted a descriptive analysis of the results from studies on the use of the drug published so far. A total of 187 patients qualified for analysis. They were divided into four main categories, including steroid-refractory and responsive adults and children. The median frequencies of an early and a sustained response were 77 and 44.5%. These data suggest that adult non-steroid-refractory, and paediatric patients may respond with the highest frequency. While it is obligatory to wait for the yield of the ongoing controlled trials before any conclusion on these indications is drawn, the data provide seminal ideas to further investigations, including the hypothesis to inaugurate with infliximab a top-down strategy for the treatment of inflammatory bowel disease.

Antibodies, Monoclonal↗
PubMed2004

[Need for hospital admission in patients with ulcerative colitis during maintenance with azathioprine].

AIM: The aim of this study is to analyse the clinical course of ulcerative colitis during maintenance therapy with azathioprine, a drug which is still not proved to be able to modify the natural history of the disease. METHODS: A retrospective study is made of data regarding the frequency of hospital admission for patients with ulcerative colitis referring to a gastroenterological Day-Hospital between 1991 and 2000. The disease history of these patients has been divided into 2 sections: one preceding and the other following an index-event, identified as the beginning of a maintenance regimen with azathioprine; this allowed to find possible differences in the clinical course after the index-event. Patients were controls of themselves. RESULTS: Seventeen patients qualified for analysis. Remission from an acute severe attack of ulcerative colitis was reached by intravenous or oral cyclosporine for 14 of them and by prednisone for 3 of them. The maintenance treatment with azathioprine, which started in all but 1 patient (intention-to-treat), showed a reduction in the number of hospital admissions, decreasing from a mean of 2.12+/-0.69 in the preceding 4.2+/-4.3 years to a mean of 0.12+/-0.33 in the following 5.8+/-2.5 years (p=0.000). CONCLUSIONS: Patients undergoing maintenance therapy with azathioprine showed face fewer relapses needing hospitalisation than those without azathioprine.

Adolescent↗
PubMed2003

Detection and quantitative estimation of Dehalococcoides spp. in a dechlorinating bioreactor by a combination of fluorescent in situ hybridisation (FISH) and kinetic analysis.

The unique capacity of Dehalococcoides ethenogenes of completely dechlorinating the common groundwater pollutant tetrachloroethene (PCE) to the harmless ethene makes this microorganism very attractive for application in natural or engineered bioremediation systems. In this study, the qualitative and quantitative determination of Dehalococcoides spp. in a lab-scale bioreactor was performed based on the combination of fluorescent in situ hybridisation (FISH) for specific detection, and kinetic batch tests at non-limiting hydrogen and PCE concentration for quantitative determination. The dechlorinating bioreactor was operated at a high and constant PCE loading rate of 255 micromol PCE [g volatile suspended solids (VSS)](-1) day(-1). Pale coccoid cells resembling the distinctive morphotype of D. ethenogenes were present in the microbial culture. These cocci hybridised with both eubacterial probes and the Dhe1259t probe recently designed for detecting Dehalococcoides spp. Positive hybridisation was also observed when the DHC1377 reverse primer was used as a specific probe and applied to the dechlorinating microbial consortium. The maximum dechlorination rate obtained under non-limiting hydrogen and PCE concentrations was 3.22 +/- 0.08 mmol Cl(-) l(-1 )day(-1). From the specific activity of D. ethenogenes [i.e. 0.055 +/- 0.008 mmol Cl(-) (mg VSS)(-1) day(-1)], as reported from pure culture study, this observed maximum rate corresponded to a concentration of this bacterium in the mixed liquor of the bioreactor of 59.0+/-10.4 mg VSS.l(-1) (41.5+/-11.2% of overall VSS). This calculated relative abundance of D. ethenogenes was in agreement with the percentage of methanol (in terms of reducing equivalents) channeled to reductive dechlorination (approximately 30%) supporting the assumption that most reductive dechlorination was actually due to this microorganism.

Biodegradation, Environmental↗
PubMed2002

"Microthrix parvicella": a new approach for kinetic and physiological characterization.

Two strains of "Microthrix parvicella" (RN1 and 4B strains) have been physiologically and kinetically characterized by utilizing a new technique particularly suitable for slow growing bacteria. The proposed method is based on the Total Extended Filament Length (TEFL) measure on filaments grown on agar surfaces. This allows us to study more easily and rapidly slow growing bacteria under many different conditions without altering the growth environment during the test. "Microthrix parvicella" appears to have versatile physiological capabilities allowing effective competition against other bacteria in the complex biocenosis of activated sludge. Main peculiarities of this organism are its storage capabilities under an aerobic/anoxic/anaerobic reaction environment, the resistance to long periods of anoxic/anaerobic conditions, the possibility of growing with appreciable kinetics at very low temperatures. In the kinetic characterization low Ks values have been observed; this finding supports the assumption that "Microthrix parvicella" is a "Ks- strategist" with high substrate affinity. Kinetics tests performed in a mixed population of activated sludge bacteria and on pure culture of filaments isolated from the same sludge sample showed that no beneficial effect on the growth rates of "Microthrix parvicella" seems attributable to the presence of activated sludge. This last result confirms the validity of pure culture studies for this microorganism and the reliability of physiological and kinetic data so evaluated in describing real systems.

Actinobacteria↗
PubMed2002

Phylogenetic analysis and in situ identification of "Nostocoida limicola"-like filamentous bacteria in activated sludge from industrial wastewater treatment plants.

The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened activated sludge samples from different industries with sometimes severe bulking sludge problems. A special focus was paid to filaments which resembled "Nostocoida limicola", a filamentous bacterium which was found to be present in many WWTPs. These filamentous bacteria are hardly cultivable and only one strain was obtained and maintained in co-culture with a yeast. The 16S rRNA sequences of several other "Nostocoida limicola"-like filamentous bacteria from different sludge samples were obtained by micromanipulation and different molecular-biological methods. The sequences were phylogenetically analyzed and specific molecular probes were developed and applied. The results clearly demonstrate that "Nostocoida limicola"-like filaments from industrial WWTPs are different from all other "Nostocoida limicola" types investigated so far. Our strains are affiliated to the alpha-subclass of Proteobacteria.

DNA Primers↗
PubMed2001

Synthesis of intracellular storage polymers by Amaricoccus kaplicensis, a tetrad forming bacterium present in activated sludge.

AIMS: The study investigated the physiology of Amaricoccus kaplicensis to determine whether it could outcompete polyphosphate accumulating bacteria in activated sludge systems removing phosphorus, by preferentially assimilating substrates in the anaerobic stages of these processes. METHODS AND RESULTS: The storage processes were investigated under anaerobic, anoxic and aerobic conditions in both batch and periodically fed cultures in an aerobic sequencing batch reactor (SBR). Amaricoccus kaplicensis showed a high capacity for storing aerobically large amounts of acetate as poly beta-hydroxybutyrate (PHB) at high rates. However, no acetate assimilation under anaerobic conditions and very slow assimilation under anoxic conditions could be detected. CONCLUSION: Amaricoccus kaplicensis in pure culture does not behave as polyphosphate accumulating bacteria competitor; therefore it is difficult to understand why anaerobic/aerobic systems often contain such large numbers of Amaricoccus cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Amaricoccus kaplicensis is probably not responsible for the failure of activated sludge systems removing phosphorus, and other organisms capable of anaerobic substrate assimilation should be sought.

Acetates↗
PubMed2000

Mutation analysis of the entire PKD1 gene: genetic and diagnostic implications.

Mutation screening of the major autosomal dominant polycystic kidney disease (ADPKD) locus, PKD1, has proved difficult because of the large transcript and complex reiterated gene region. We have developed methods, employing long polymerase chain reaction (PCR) and specific reverse transcription-PCR, to amplify all of the PKD1 coding area. The gene was screened for mutations in 131 unrelated patients with ADPKD, using the protein-truncation test and direct sequencing. Mutations were identified in 57 families, and, including 24 previously characterized changes from this cohort, a detection rate of 52.3% was achieved in 155 families. Mutations were found in all areas of the gene, from exons 1 to 46, with no clear hotspot identified. There was no significant difference in mutation frequency between the single-copy and duplicated areas, but mutations were more than twice as frequent in the 3' half of the gene, compared with the 5' half. The majority of changes were predicted to truncate the protein through nonsense mutations (32%), insertions or deletions (29.6%), or splicing changes (6.2%), although the figures were biased by the methods employed, and, in sequenced areas, approximately 50% of all mutations were missense or in-frame. Studies elsewhere have suggested that gene conversion may be a significant cause of mutation at PKD1, but only 3 of 69 different mutations matched PKD1-like HG sequence. A relatively high rate of new PKD1 mutation was calculated, 1.8x10-5 mutations per generation, consistent with the many different mutations identified (69 in 81 pedigrees) and suggesting significant selection against mutant alleles. The mutation detection rate, in this study, of >50% is comparable to that achieved for other large multiexon genes and shows the feasibility of genetic diagnosis in this disorder.

Alleles↗
PubMed2000

'Candidatus Nostocoida limicola', a filamentous bacterium from activated sludge.

Five strains of 'Candidatus Nostocoida limicola' were isolated by micromanipulation from two activated sludge plants. Two (Ben17 and Ben18) were from Sunbury, Victoria, Australia, and three (Ben67, Ver1 and Ver2) were from Verona, Italy. The near complete 16S rDNA sequences were determined for five strains and the phylogenetic location of this important bulking filament in the actinomycete subphylum is reported for the first time. Phylogenetically, the Ben strains formed one group with 99.4% 16S rDNA similarity, and the Ver strains formed another with 99.9% 16S rDNA similarity. The mean similarity between the two groups was 97.4%. By 16S rDNA comparison, the closest relative to all strains was Terrabacter sp. strain DPO1361 (95.0-95.5% identical). On R2A medium, all strains generally grew as short filaments or clumps of cocci, whereas on glucose sulfide (GS) medium, all grew as irregular twisting filaments comprising Gram-positive and Gram-negative cells, which is close to their in situ morphology. Polyphosphate was stored either as granules (R2A) or throughout the trichomes (GS). None of the strains could grow without added nitrogen, reduce nitrate to nitrogen gas or grow anaerobically, whereas all could grow at 15-30 degrees C, produce catalase and reduce nitrate to nitrite. All were inactive in the Hugh & Leifson test. This paper describes 'Candidatus Nostocoida limicola'.

Actinomycetales↗
PubMed2000

Phylogenetic characterization and in situ detection of a Cytophaga-Flexibacter-Bacteroides phylogroup bacterium in Tuber borchii vittad. Ectomycorrhizal mycelium.

Mycorrhizal ascomycetous fungi are obligate ectosymbionts that colonize the roots of gymnosperms and angiosperms. In this paper we describe a straightforward approach in which a combination of morphological and molecular methods was used to survey the presence of potentially endo- and epiphytic bacteria associated with the ascomycetous ectomycorrhizal fungus Tuber borchii Vittad. Universal eubacterial primers specific for the 5' and 3' ends of the 16S rRNA gene (16S rDNA) were used for PCR amplification, direct sequencing, and phylogenetic analyses. The 16S rDNA was amplified directly from four pure cultures of T. borchii Vittad. mycelium. A nearly full-length sequence of the gene coding for the prokaryotic small-subunit rRNA was obtained from each T. borchii mycelium studied. The 16S rDNA sequences were almost identical (98 to 99% similarity), and phylogenetic analysis placed them in a single unique rRNA branch belonging to the Cytophaga-Flexibacter-Bacteroides (CFB) phylogroup which had not been described previously. In situ detection of the CFB bacterium in the hyphal tissue of the fungus T. borchii was carried out by using 16S rRNA-targeted oligonucleotide probes for the eubacterial domain and the Cytophaga-Flexibacter phylum, as well as a probe specifically designed for the detection of this mycelium-associated bacterium. Fluorescent in situ hybridization showed that all three of the probes used bound to the mycelium tissue. This study provides the first direct visual evidence of a not-yet-cultured CFB bacterium associated with a mycorrhizal fungus of the genus Tuber.

Ascomycota↗
PubMed1999

Polycystin-1 expression in PKD1, early-onset PKD1, and TSC2/PKD1 cystic tissue.

BACKGROUND: The mutational mechanism responsible for cyst formation in polycystic kidney disease 1 gene (PKD1) remains controversial, with data indicating a two-hit mechanism, but also evidence of polycystin-1 expression in cystic tissue. METHODS: To investigate this apparent paradox, we analyzed polycystin-1 expression in cystic renal or liver tissue from 10 patients with truncating PKD1 mutations (including one early-onset case) and 2 patients with severe disease associated with contiguous deletions of TSC2 and PKD1, using monoclonal antibodies (mAbs) to both extreme N-(7e12) and C-terminal (PKS-A) regions of the protein. Truncation of the C-terminal epitope from the putative mutant proteins in each case allowed exclusive assessment of the nontruncated protein with PKS-A. RESULTS: In adult PKD1 tissue, the majority of cysts (approximately 80%) showed polycystin-1 expression, although staining was absent in a variable but significant minority (approximately 20%), in spite of the normal expression of marker proteins. Unlike adult PKD1, however, negative cysts were rarely found in infantile PKD1 or TSC2/PKD1 deletion cases. CONCLUSIONS: If a two-hit mutational mechanism is operational, these results suggest that the majority of somatic mutations in adult PKD1 are likely to be missense changes. The low level of polycystin-1-negative cysts in the three "early-onset" cases, however, suggests that a somatic PKD1 mutation may not always be required for cyst formation.

Adult↗