1,721,102 research outputs found
Modelli di stress ossidativo per la medicina personalizzata delle patologie croniche epato-gastrointestinali umane: il modello della malattia diverticolare
Full text linkLa patofisiologia della malattia diverticolare non è ancora del tutto chiara, tuttavia recenti studi condotti su modelli ex-vivo di colon umano hanno evidenziato la presenza di stress ossidativo che interessa l’intero spessore della parete colica nonostante la sua origine resti ancora ignota. Lo scopo principale del progetto è lo studio approfondito sullo stress ossidativo nei diversi quadri clinici della malattia diverticolare che vanno dalla diverticolosi asintomatica alla malattia diverticolare complicata per chiarire il possibile ruolo patogenetico nei vari stadi di malattia e quindi identificare nuove possibile strategie terapeutiche. Nel dettaglio lo studio è stato condotto parallelamente sia in modelli ex-vivo di malattia che in-vivo per ricercare i biomarcatori diretti di danno ossidativo, sia biomarcatori che dimostrino la perdita di antiossidanti legati al danno. In ultimo, per rafforzare il valore traslazionale dello studio è stato predisposto un modello in-vitro con il fine di valutare il potere benefico dell’antiossidante N-acetil cisteina nella reversione del danno ossidativo. Complessivamente le analisi dei tessuti del modello ex-vivo condotte hanno evidenziato sia in campioni di diverticolosi che di malattia diverticolare complicata un incremento di fibrosi parallelamente alla perdita dell’architettura del muscolo, accompagnati dal rilievo dei marker di switch fenotipico a livello cellulare. Nei tessuti di entrambi i fenotipi della patologia è stato riscontrato l’incremento di marker ossidativi quali proteine ossidate e presenza di nitrotirosina, parallelamente alla perdita di molecole legate al mondo antiossidante come Tioredossina-1 e fattore di trascrizione nucleare eritroide-2. Queste alterazioni si accompagnano all’incremento del fattore di ipossia HIF-1a riscontrato sia nella diverticolosi che nella malattia diverticolare complicata. Le alterazioni ossidative riscontrate si confermano inoltre anche a livello sistemico nei sieri del modello in-vivo. In dettaglio, rispetto al controllo, i campioni di diverticolosi e malattia diverticolare complicata hanno evidenziato l’incremento di H2O2 parallelamente alla perdita del potere antiossidante e l’incremento di LPS circolante e zonulina. Considerando il ruolo preponderante del mitocondrio nella genesi della malattia diverticolare particolare rilevo è stato dato allo studio di questo organello. Analisi ex-vivo condotte tramite microscopia elettronica hanno evidenziato un incremento del numero di mitocondri nei campioni patologici e l’aumento di fenomeni quali frammentazione e fusione mitocondriale. Analisi della catena di trasporto degli elettroni hanno evidenziato l’alterazione del complesso proteico II e IV della catena facendo presupporre un danno di tipo funzionale confermato a livello cellulare dall’incremento della massa mitocondriale, perdita del potenziale di membrane e perdita di antiossidanti. In modo interessante l’analisi del modello in-vitro, che prevedeva l’incubazione delle cellule con N-acetil cisteina, ha mostrato dei dati positivi in merito al ripristino della funzionalità delle cellule e del contenuto di antiossidante sia nella diverticolosi che nella malattia diverticolare complicata in seguito all’incubazione con questo antiossidante. In conclusione, le informazioni ottenute da questo studio ci hanno permesso di confermare la presenza di cambiamenti morfologici nel muscolo dovuti a cambiamenti dello stato ossidativo e perdita di antiossidanti attraverso un modello ex-vivo. Si noti che tutti questi cambiamenti influenzano gradualmente sia la diverticolosi che la malattia diverticolare complessa, suggerendo per la prima volta che non si tratta di due patologie diverse, ma di due condizioni con lo stesso quadro clinico. Di fondamentale importanza traslazionale, i cambiamenti di cui sopra sono parzialmente reversibili mediante il trattamento con antiossidanti, aprendo potenzialmente nuove strade per l’uso terapeutico di queste molecole nel trattamento della MD
Update on the biopesticide regulation and development of protein-based products for the biocontrol of crop diseases
Full text linkIn the last decades, concerns on the negative drawbacks of chemical pesticides on human health and environment have raised interest in safer alternatives; biopesticides, such as biogenic elicitors, represent an encouraging solution. The regulatory approach in the European Union does not distinguish biopesticides as a specific category of plant protection, and for this reason they are subjected to the same regulations as synthetic chemicals, requiring several authorization steps for the final approval and marketing. Among others, protein-based products and peptide fragments can stimulate plant growth, and represent a wide category of elicitors able to reduce the symptoms of common crop diseases, by acting as stimulators of plant defence and influencing systemic resistance processes, which can be regarded as effective alternative to synthetic chemical pesticides. The final objective of the current doctoral project was to provide new insights on the use of bioactive protein-based products against crop diseases, to further develop new sustainable strategies for organic agricultural practices. More in details, as well as providing an updated overview of the regulatory procedures for the authorization of biopesticides, the specific goals of the present research were i) to characterize the mode of action of protein-based products against crop diseases and ii) to optimize a method for the low-cost production of bioactive protein-based products. For this purpose, we analysed the mechanisms of action of a protein derivative called nutrient broth (NB) against grapevine downy mildew (caused by Plasmopara viticola), focusing on its roles as resistance inducer and nutritional source for phyllosphere microbial populations (Chapter 2). We showed that NB reduced downy mildew symptoms and induced the expression of defence-related genes in greenhouse- and in vitro-grown plants, indicating the activation of grapevine defence processes. Furthermore, NB increased the number of culturable phyllosphere bacteria, and altered the composition of bacterial and fungal populations on grapevine leaves. Thus, modifications in the structure of leaf populations caused by NB application could partially contribute to downy mildew control by competition for space/nutrients with the pathogen or other biocontrol strategies. Particularly, changes in the abundance of phyllosphere microorganisms may provide a cont ribution to the resistance induction, partially affecting the hormone-mediated signalling pathways involved. Later, we optimized an experimental procedure to develop low-cost protein hydrolysates starting from plant agro-industrial by-products, since animal-derived protein derivatives may create concerns about food safety (Chapter 3). Particularly, we compared the effect of enzymatic and acid hydrolysis on different plant protein sources (soybean, rapeseed and guar protein meals), in terms of efficacy against the powdery mildew of Cucurbitaceae (caused on courgette plants by Podosphaera xanthii), investigating the potential contribution of amino acids and peptide fragment s generated during the hydrolysis to the activation of plant resistance. Our results showed that the original protein source affected the biocontrol properties of protein hydrolysates, and two hydrolysis processes improved the functional properties of guar protein meal against powdery mildew. A positive correlation was found between the efficacy and degree of hydrolysis of guar acid hydrolysates, suggesting that the hydrolysis method may enhance the functional properties of the original protein source. In addition, significant correlations were revealed between the efficacy of guar hydrolysates and concentrations of specific peptide fragments and amino acids, which may be involved in the regulation of the plant defence response. Specifically, guar enzymatic hydrolysates did not present a direct toxic effect against the germination of pathogenic conidia, suggesting a mode of action mainly based on the stimulation of plant resistance mechanisms, as observed for NB. The possibility of controlling crop diseases with the preventive foliar application of protein-based products represents an innovative approach, especially in a view of reducing harmful chemical pesticides in integrated pest management programs. However, further studies are required to fully clarify their modes of action and the impact on phyllosphere microorganisms under field conditions
Systems biology and metabolic engineering of Rhodococcus for bioconversion and biosynthesis processes
Full text linkRhodococcus spp. strains are widespread in diverse natural and anthropized environments thanks to their high metabolic versatility, biodegradation activities, and unique adaptation capacities to several stress conditions such as the presence of toxic compounds and environmental fluctuations. Additionally, the capability of Rhodococcus spp. strains to produce high value-added products has received considerable attention, mostly in relation to lipid accumulation. In relation with this, several works carried out omic studies and genome comparative analyses to investigate the genetic and genomic basis of these anabolic capacities, frequently in association with the bioconversion of renewable resources and low-cost substrates into triacylglycerols. This review is focused on these omic analyses and the genetic and metabolic approaches used to improve the biosynthetic and bioconversion performance of Rhodococcus. In particular, this review summarizes the works that applied heterologous expression of specific genes and adaptive laboratory evolution approaches to manipulate anabolic performance. Furthermore, recent molecular toolkits for targeted genome editing as well as genome-based metabolic models are described here as novel and promising strategies for genome-scaled rational design of Rhodococcus cells for efficient biosynthetic processes application
High pressure carbon dioxide on pork raw meat: Inactivation of mesophilic bacteria and effects on colour properties
No full textThe objective of the present study was the evaluation of the effectiveness of High Pressure Carbon Dioxide (HPCO2) as a non-thermal technology for the pasteurization of porcine raw meat. The inactivation kinetics of mesophilic bacteria were determined at 25, 35 and 40 °C, from 6 to 16 MPa and from 5 to 60 min. The effects of HPCO2 on the colour parameters in terms of L∗, a∗, b∗ and ΔE during and after the treatment were investigated by means of a spectroscopic apparatus. Data demonstrated that HPCO2 treatment assured at least 2 Log (CFU/cm2) reduction of mesophilic microorganisms, but induced significant colours alterations: lightness increased and redness decreased and the samples turned whitish and looked like “cooked”. The technology could hardly be exploited at industrial scale for raw meat pasteurization due to the colour modifications induced to the product
Supercritical carbon dioxide combined with high power ultrasound: An effective method for the pasteurization of coconut water
No full textEndonasal Endoscopic Approaches for Anterior Skull Base Meningiomas: Evaluation of Potential Benefits on Outcome Compared with Transcranial Approaches
No full textObjective: Identify potential advantages in endonasal surgical aspiration of this kind of lesion, considering several cases from our transcranial series, which could have been treated also by endoscopic route. Study Design: Midline anterior skull base meningiomas have been traditionally treated via transcranial approaches. Recently, the endoscopic endonasal approach has been introduced for the surgical treatment of such lesions. The actual advantages of the latter approach in terms of outcome are not clear yet. Methods: We analyzed a series of 94 patients treated for olfactory groove or tuberculum sellae meningiomas during the past 13 years. We selected 25 cases who had radiological characteristics that suggest resectability by endoscopic route. Inclusion criteria for the use of expanded endoscopic endonasal approaches are: size less than 4 cm; absence of carotid encasement, or cavernous sinus invasion; no optical nerves involvement, absence of optical canal invasion; extension not above the middle orbital line; anterior limits crista galli and frontal sinus; predominant midline location. We took into consideration several parameters regarding the postoperative course of our patients. Results: Transcranial microsurgical approaches are still the first choice for treatment of midline anterior skull base meningiomas because they allow treating lesions with any characteristics. Conclusion: Transcranial route offer a greater chance of complete removal and lower risk of CSF fistula
Some facts about the respiratory enzymes of Pseudomonas pseudoalcaligenes KF707 recently renamed as Pseudomonas furukawaii sp. nov., type strain KF707
No full textRecently proposed renaming the obligate aerobe Pseudomonas pseudoalcaligenes KF707 as Pseudomonas furukawiisp. nov. type strain KF707. Since the first quasi-complete genome sequence of KF707 was reported in 2012 (accession number: PRJNA83639) numerous reports on chemotaxis and function/composition of the respiratory redox chain of KF707 have been published, demonstrating that KF707 contains three cheA genes for aerobic motility, four cytochrome oxidases of c(c)aa3- and cbb3-type and one bd-type quinol oxidase. With this background in mind, it has been quite a surprise to read within Table 1 of the paper by Kimura et al. that strain KF707 is phenotypically characterized as cytochrome oxidase-negative. Further, Table 1 also reports that KF707 is b-galactosidase-positive, an affirmation that is not consistent with results documented in the current literature. In this present ‘Letter to the Editor’ we show that Kimura et al. have contradicted themselves and provided inaccurate information in respect to the respiratory phenotypic features of P. furukawii
Partial permeabilisation and depolarization of Salmonella enterica Typhimurium cells after treatment with pulsed electric fields and high pressure carbon dioxide
No full textInteraction of Rhodococcus with Metals and Biotechnological Applications
No full textIn studies of environmental stresses caused by metals, Rhodococcus species are routinely identified as part of a beneficial microbial rhizosphere community. These bacterial strains, inhabiting diverse ecological niches, possess a variety of enzymatic activities to carry out relevant biodegradation reactions, such as degradation of organic pollutants in some cases using them for both carbon and energy. In this context, most Rhodococcus strains have been found to have very high levels of metal resistance. Thus, these microorganisms are not only capable of metabolizing various organic pollutants in the presence of co-contaminating heavy metals, but they can also bioadsorb and/or bioconvert various metals and metalloids [metal(loid)s]. Indeed, some Rhodococcus exploit these metal(loid) compounds to generate biogenic nanoscale materials of intriguing physical-chemical properties, which can find applications in biotechnology.
This book chapter has the focus in overviewing the biotechnological relevance of the Rhodococcus genus relationship with metal(loid)s, the bioprocesses elicited by these microorganisms in handling metal(loid)s’ toxicity, and the importance of these actinomycetes in the context of the bioremediation and bionanotechnology fields
Characterization of methanotrophic microbial community in a soil sample from Terre Calde di Medolla (Italy)
No full textMethane-oxidizing bacteria (methanotrophs) have a ubiquitous distribution in the environment and play an important role in global climate warming by lowering methane emission into the atmosphere. “Terre Calde di Medolla” (literally, “Warm Earths of Medolla”) refers to a farming area, located near the town of Modena (Emilia-Romagna region, northern Italy), which has always been known for the relatively high temperatures of the soil. After the 2012 Emilia earthquake that affected this area, soil temperatures of 44°C were revealed (20–25°C above the local background value) together with diffuse soil fluxes of methane (CH4) and minor, though significant, of carbon dioxide (CO2). Ground heating and gas seepage appeared to be spatially correlated, thus suggesting a close relationship between the two phenomena.The aim of this work was to characterize the methanotrophic microbial community present in soil samples collected from this area using a cultivation-independent approach. We performed clone library analysis and terminal restriction fragment length polymorphism (T-RFLP) fingerprinting of the 16S rDNA and pmoA gene (coding for the alpha-subunit of the particulate methane monooxygenase). Results from 16S rDNA analysis showed that methanotrophic bacteria represented around 10% of the entire microbial community. In particular, bacteria belonging to Acidobacteria and Actinobacteria phyla were detected as well as members of Ammonifex, Sphingomonas and Bacillus genera.
Through the analysis of pmoA gene, Methylococcus, Methylocaldum and Methylomonas were found to be the dominant genera (around 90%) of the methanotrophic community under analysis. In addition to these Gammaproteobacteria, Methylocystis spp. were detected which belong to Alphaproteobacteria class. Further studies will define the correlation between the composition and the role of the methanotrophic microbial community and the peculiar characteristics of “Terre Calde di Medolla” soil
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