| 1. |
- Aulitto, Martina, et al.
(författare)
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Thermus thermophilus as source of thermozymes for biotechnological applications: homologous expression and biochemical characterization of an alpha-galactosidase
- 2017
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Ingår i: Microbial Cell Factories. - : Springer Science and Business Media LLC. - 1475-2859. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The genus Thermus, which has been considered for a long time as a fruitful source of biotechnological relevant enzymes, has emerged more recently as suitable host to overproduce thermozymes. Among these, alpha-galactosidases are widely used in several industrial bioprocesses that require high working temperatures and for which thermostable variants offer considerable advantages over their thermolabile counterparts. Results: Thermus thermophilus HB27 strain was used for the homologous expression of the TTP0072 gene encoding for an a-galactosidase (TtGalA). Interestingly, a soluble and active histidine-tagged enzyme was produced in larger amounts (5 mg/L) in this thermophilic host than in Escherichia coli (0.5 mg/L). The purified recombinant enzyme showed an optimal activity at 90 degrees C and retained more than 40% of activity over a broad range of pH (from 5 to 8). Conclusions: TtGalA is among the most thermoactive and thermostable a-galactosidases discovered so far, thus pointing to T. thermophilus as cell factory for the recombinant production of biocatalysts active at temperature values over 90 degrees C.
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| 2. |
- Carbonaro, Miriam, et al.
(författare)
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Exploration of three Dyadobacter fermentans enzymes uncovers molecular activity determinants in CE15
- 2024
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Ingår i: Applied Microbiology and Biotechnology. - 1432-0614 .- 0175-7598. ; 108:1
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Tidskriftsartikel (refereegranskat)abstract
- Glucuronoyl esterases (GEs) are serine-type hydrolase enzymes belonging to carbohydrate esterase family 15 (CE15), and they play a central role in the reduction of recalcitrance in plant cell walls by cleaving ester linkages between glucuronoxylan and lignin in lignocellulose. Recent studies have suggested that bacterial CE15 enzymes are more heterogeneous in terms of sequence, structure, and substrate preferences than their fungal counterparts. However, the sequence space of bacterial GEs has still not been fully explored, and further studies on diverse enzymes could provide novel insights into new catalysts of biotechnological interest. To expand our knowledge on this family of enzymes, we investigated three unique CE15 members encoded by Dyadobacter fermentans NS114T, a Gram-negative bacterium found endophytically in maize/corn (Zea mays). The enzymes are dissimilar, sharing ≤ 39% sequence identity to each other' and were considerably different in their activities towards synthetic substrates. Combined analysis of their primary sequences and structural predictions aided in establishing hypotheses regarding specificity determinants within CE15, and these were tested using enzyme variants attempting to shift the activity profiles. Together, the results expand our existing knowledge of CE15, shed light into the molecular determinants defining specificity, and support the recent thesis that diverse GEs encoded by a single microorganism may have evolved to fulfil different physiological functions. KEY POINTS: • D. fermentans encodes three CE15 enzymes with diverse sequences and specificities • The Region 2 inserts in bacterial GEs may directly influence enzyme activity • Rational amino acid substitutions improved the poor activity of the DfCE15A enzyme.
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| 3. |
- Carbonaro, Miriam, et al.
(författare)
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Genomic mining of Geobacillus stearothermophilus GF16 for xylose production from hemicellulose-rich biomasses using secreted enzymes
- 2024
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Ingår i: New Biotechnology. - 1876-4347 .- 1871-6784. ; 82, s. 14-24
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Tidskriftsartikel (refereegranskat)abstract
- The valorization of lignocellulosic biomass, derived from various bio-waste materials, has received considerable attention as a sustainable approach to improve production chains while reducing environmental impact. Microbial enzymes have emerged as key players in the degradation of polysaccharides, offering versatile applications in biotechnology and industry. Among these enzymes, glycoside hydrolases (GHs) play a central role. Xylanases, in particular, are used in a wide range of applications and are essential for the production of xylose, which can be fermented into bioethanol or find use in many other industries. Currently, fungal secretomes dominate as the main reservoir of lignocellulolytic enzymes, but thermophilic microorganisms offer notable advantages in terms of enzyme stability and production efficiency. Here we present the genomic characterization of Geobacillus stearothermophilus GF16 to identify genes encoding putative enzymes involved in lignocellulose degradation. Thermostable GHs secreted by G. stearothermophilus GF16 were investigated and found to be active on different natural polysaccharides and synthetic substrates, revealing an array of inducible GH activities. In particular, the concentrated secretome possesses significant thermostable xylanase and β-xylosidase activities (5 ×103 U/L and 1.7 ×105 U/L, respectively), highlighting its potential for application in biomass valorization. We assessed the hemicellulose hydrolysis capabilities of various agri-food wastes using the concentrated secretome of the strain cultivated on xylan. An impressive 300-fold increase in xylose release compared to a commercially available cocktail was obtained with the secretome, underscoring the remarkable efficacy of this approach.
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| 4. |
- Dorofte, Luiza, 1982-, et al.
(författare)
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Low level of interobserver concordance in assessing histological subtype and tumor grade in patients with penile cancer may impair patient care
- 2022
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Ingår i: Virchows Archiv. - : Springer. - 0945-6317 .- 1432-2307. ; 480:4, s. 879-886
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Tidskriftsartikel (refereegranskat)abstract
- Differentiation between penile squamous cell carcinoma patients who can benefit from limited organ-sparing surgery and those at significant risk of lymph node metastasis is based on histopathological prognostic factors including histological grade and tumor histological subtype. We examined levels of interobserver and intraobserver agreement in assessment of histological subtype and grade in 207 patients with penile squamous cell carcinoma. The cases were assessed by seven pathologists from three hospitals located in Sweden and Italy. There was poor to moderate concordance in assessing both histological subtype and grade, with Fleiss kappas of 0.25 (range: 0.02-0.48) and 0.23 (range: 0.07-0.55), respectively. When choosing HPV-associated and non-HPV-associated subtypes, interobserver concordance ranged from poor to good, with a Fleiss kappa value of 0.36 (range: 0.02-0.79). A re-review of the slides by two of the pathologists showed very good intraobserver concordance in assessing histological grade and subtype, with Cohen's kappa values of 0.94 and 0.91 for grade and 0.95 and 0.84 for subtype. Low interobserver concordance could lead to undertreatment and overtreatment of many patients with penile cancer, and brings into question the utility of tumor histological subtype and tumor grade in determining patient treatment in pT1 tumors.
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| 5. |
- Ricci, Costantino, et al.
(författare)
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HPV Status and World Health Organization 2016 Classification of Penile Squamous Cell Carcinoma and Penile Intraepithelial Neoplasia : 206 Cases from a Single, Contemporary, Western Cohort of Patients with Emphasis on the "Discordant Cases"
- 2020
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Ingår i: Modern Pathology. - : Nature Publishing Group. - 0893-3952 .- 1530-0285. ; 33:Suppl 2, s. 960-961
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: Penile squamous cel carcinoma (pSCC) cancer has been considered a rare tumour in the western world. Although some conflicting results, the most recent meta-analyses report an increase in its incidence and in the percentage of HPV(+) cases in numerous western countries. This scenario mirrors what observed for HPV(+) oropharynx cancer and could be explained by changes in sexual practice and in exposure of men to HPV. In this study, we analyzed pathological features and HPV-DNA prevalence in a contemporary, western pSCC cohort.Design: This study enrolled 206 patients with pSCC from Örebro University. DNA was extracted from paraffin-embedded tumor tissue samples, and HPV-DNA genotyping were performed using PCR method Anyplex II HPV28. In a subset of cases, HPV-DNA was also assessed in penile intraepithelial neoplasia (PeIN), lymph node metastasis (LnM) or both (51%, 11.6% and 18.9%). All the cases have been histologically re-classified according to the WHO 2016 classification of pSCC.Results: HPV -DNA was detected in 92/206 (44.7%) pSCC, 78/141 (55.3%) PeIN and 28/61 LnM (45.9%), respectively. HPV16 was the predominant type, representing 78.3% for pSCC, 79.5% for PeIN and 96.4% for LnM. In 7.8% of the cases, more than a HPV genotype has been detected in the same specimen or in different specimens of the same patients. Curiously, we found 8.5% of cases (14/164) with discordance of HPV-DNA detection in different specimens from the same patient (pSCC, PeIN and/or /LnM). In HPV(+) pSCC the predominant histologic subtype was “warty” (41.3%); in HPV(-) pSCC it was “usual” (65.8%). For PeIN, “warty” was the predominant subtype in HPV(+) PeIN (39.7%) and “differentiated” in HPV(-) PeIN (79.4%). For pSCC, we observed disagreement between histology and HPV status in 23.8% of cases: 13.1% HPV(+)/Non-HPV -related histology and 10.7% HPV(-)/HPV-related histology.Conclusions: HPV -DNA was observed in a relevant portion of pSCC and PeIN in our case series, confirming an increasing role of HPV in the pathogenesis of this disease. These results are particularly relevant, as they reflect the current epidemiological trend in the western world. Future studies are needed to clarify the exact role of HPV in cases with discordance between histology and HPV status and in cases with disagreement of HPV detection in different specimens from the same patient (pSCC, PeIN and/or LnM).
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| 6. |
- Rizzo, Cinzia, et al.
(författare)
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IgG1 and IgG4 Antibody Responses to the Anopheles gambiae Salivary Protein gSG6 in the Sympatric Ethnic Groups Mossi and Fulani in a Malaria Hyperhendemic Area of Burkina Faso
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:4, s. e96130-
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Tidskriftsartikel (refereegranskat)abstract
- Human antibody response to the Anopheles gambiae salivary protein gSG6 has recently emerged as a potentially useful tool for malaria epidemiological studies and for the evaluation of vector control interventions. However, the current understanding of the host immune response to mosquito salivary proteins and of the possible crosstalk with early response to Plasmodium parasites is still very limited. We report here the analysis of IgG1 and IgG4 subclasses among anti-gSG6 IgG responders belonging to Mossi and Fulani from Burkina Faso, two ethnic groups which are known for their differential humoral response to parasite antigens and for their different susceptibility to malaria. The IgG1 antibody response against the gSG6 protein was comparable in the two groups. On the contrary, IgG4 titers were significantly higher in the Fulani where, in addition, anti-gSG6 IgG4 antibodies appeared in younger children and the ratio IgG4/IgG1 stayed relatively stable throughout adulthood. Both gSG6-specific IgG1 and IgG4 antibodies showed a tendency to decrease with age whereas, as expected, the IgG response to the Plasmodium circumsporozoite protein (CSP) exhibited an opposite trend in the same individuals. These observations are in line with the idea that the An. gambiae gSG6 salivary protein induces immune tolerance, especially after intense and prolonged exposure as is the case for the area under study, suggesting that gSG6 may trigger in exposed individuals a Th2-oriented immune response.
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