1,721,039 research outputs found
Caratterizzazione fitochimica dei semi di Theobroma cacao L. per valutare la provenienza geografica, la varietà e il processo di fermentazione di differenti cultivar
No full textNelle piante, produzione, profilo e contenuto dei metaboliti secondari dipendono da un ampio numero di fattori, tra cui il genotipo, le condizioni climatiche e agronomiche, la raccolta, la fase di stoccaggio e di lavorazione. Questi fattori influiscono sulla qualità dei prodotti derivati e quindi sul loro valore economico.
L’obiettivo di questo lavoro è stato quello di studiare i semi di Theobroma cacao L., utilizzati per la produzione del cioccolato e del burro di cacao, mediante la determinazione del contenuto della componente polifenolica, xantinica e lipidica in base a diversi fattori, cioè zona geografica di raccolta, varietà o cultivar, tipo di fermentazione e filiera di lavorazione. Sono stati utilizzati molteplici dispositivi analitici per ottenere informazioni complementari e quindi il più possibile complete, per definire un quadro metabolico completo in confronto con gli studi in letteratura generalmente limitati ad una classe di metaboliti
Analisi di multi ingredienti di origine vegetale mediante un nuovo metodo basato sul fingerprint HPTLC
No full textAnalysis of multi-ingredient food supplements by fingerprint HPTLC approach
Full text linkThe increase of import/export of every kind of herbal products calls urgently for adequate controls. Analysis of herbal food supplement (botanicals) is a difficult task, like in the composition determination of a multi-ingredient product, where several botanical drugs were used. Actually, this is an important argument in consideration of health security. The authors reported the results of an analytical approach based on HPTLC (high performance thin layer chromatography) fingerprints comparison and tailored to determine the composition of marketed multi-ingredient botanicals. The method gave positive data in case of the presence
of 3-5 species, whereas difficulties were recorded when the number of plants is increased
The role of CpsABCD in Streptococcus agalactiae capsule biosynthesis
Full text linkStreptococcus agalactiae or group B Streptococcus (GBS) is a Gram-positive bacterium asymptomatically colonizing 15-35% of women in the gastrointestinal and urogenital tracts. During delivery, neonates born to mothers who carry GBS can be infected themselves and develop severe diseases such as sepsis, pneumonia and meningitis. Pre-partum screenings and prophylactic treatment with antibiotics have reduced the incidence of neonatal GBS disease to 0.04% in USA. But still, in the western world, S. agalactiae represents the major cause of bacterial meningitis in newborns and half of the infected suffer long-term neurodevelopmental defects. Moreover, GBS has also emerged as a pathogen in other patient populations such as the elderly, pregnant women, diabetics and individuals who are immunocompromised. Vaccines based on the capsule polysaccharide (CPS) of this pathogen are currently under development.
The CPS is the main virulence factor of GBS, preventing complement deposition and opsonophagocytosis. The production of a CPS is ubiquitous in bacteria, and the Wzy pathway constitutes one of the prototypical mechanisms to produce these structures. This pathway has been characterized in detail in S. pneumoniae. Briefly, the repeating units of sugars composing the CPS are synthesized inside the cell by a group of glycosyltransferases. The repeating units are then flipped outside the membrane and incorporated into the growing polysaccharide chain by a polymerase. Lastly, the polysaccharide is attached to the cell wall peptidoglycan to create the CPS layer surrounding the bacterium. All the enzymes involved in this process are encoded in a single operon.
The aim of this work is to investigate the role of the CpsABCD proteins encoded in the cps operon of GBS. These proteins are highly conserved in all GBS serotypes, as well as in some other related bacteria, but they are not involved in the synthesis of the basic repeating units of sugars. CpsA is reported to be a transcriptional regulator and/or an enzyme attaching the CPS to the cell wall. CpsBCD homologous proteins in S. pneumoniae constitute a putative phosphoregulatory system, but their role in GBS capsule biosynthesis is unclear. To investigate the role of these proteins we developed twelve knockout and functional GBS mutant strains and we examined them for CPS quantity, size, and attachment to the cell surface, as well as CpsD phosphorylation. Moreover, we used a bacterial two hybrid assay to investigate interdependencies between these proteins.
We observed that in GBS CpsB, C and D constitute a phosphoregulatory system where the CpsD autokinase phosphorylates its C-terminal tyrosines in a CpsC-dependent manner. These Tyr residues are also the target of the cognate CpsB phosphatase. Analysis of cps operon transcription by qRT-PCR on the mutant strains suggested that CpsABCD are not involved in transcriptional regulation of this operon. Furthermore, all the mutant strains retained the capability to produce a CPS, confirming that these proteins are not involved in the synthesis of polysaccharides, however, differences in CPS length and attachment to the cell wall were observed. In particular, we observed that the CpsC extracellular domain appeared necessary for the production of high molecular weight polysaccharides and that the LytR domain of CpsA is required for the attachment of the CPS to the bacterial cell surface. Protein-protein interactions between CpsD and CpsC and between CpsA and CpsC were observed.
These results allowed us to propose tentative roles for the proteins and their interdependencies. We propose a model where these proteins are fine-tuning the steps terminating the CPS biosynthesis, i.e. the balance between polymerization and attachment to the cell wall. In said model, CpsA competes with the CPS polymerase and attaches the CPS to the cell wall. This interplay depends on the cyclic phosphorylation of the CpsCD complex which modulates the activity of CpsA balancing the two competing activities.
Ultimately, to investigate how differences in CPS length, amount and localization impact on S. agalactiae ability to interact with cells, an in vitro adhesion-invasion assay, using lung epithelial cells have been tested. Our results showed that strains with CPS length different from the wild type were defective in associations to cells. Moreover, strains lacking the capsule or producing very little CPS were more efficient in invading cells irrespective of the CPS length
La rappresentazione del cambiamento climatico nel videogioco Death Stranding: un'analisi dell'impatto sulla consapevolezza dei giocatori attraverso il dialogo nelle community.
No full textNeem (Azadirachta indica A. Juss) Oil to Tackle Enteropathogenic Escherichia coli
Full text linkNeem (Azadirachta indica A. Juss) oil (NO) was assayed against forty-eight isolates of Escherichia coli by standardised disc diffusion test and microdilution test. By molecular biology characterization, fourteen isolates resulted in diarrheagenic E. coli with sixteen primer pairs that specifically amplify unique sequences of virulence genes and of 16S rRNA. The NO showed biological activity against all isolates. The bacterial growth inhibition zone by disc diffusion method (100 μL NO) ranged between 9.50 ± 0.70 and 30.00 ± 1.00 mm. The antibacterial activity was furthermore determined at lower NO concentrations (1 : 10–1 : 10,000). The percent of growth reduction ranged between 23.71 ± 1.00 and 99.70 ± 1.53. The highest bacterial growth reduction was 1 : 10 NO concentration with 50 μL of bacterial suspension (ca. 1 × 106 CFU/mL). There is significant difference between the antibacterial activities against pathogenic and nonpathogenic E. coli, as well as NO and ciprofloxacin activities. Viable cells after the different NO concentration treatments were checked by molecular biology assay using PMA dye. On the basis of the obtained results, NO counteracts E. coli and also influences the virulence of E. coli viable cells after NO treatment. The NO metabolomic composition was obtained using fingerprint HPTLC
The HPTLC approach to metabolomic determination of neem products composition
No full textAlthough seeds are the only part commercially used, determination of composition of neem marketed products is a complicated matter. Natural variability and different process methods play a key role in this variability, mainly derived from the enormous quantity of different constituents present. The chemical complexity is the necessary pre-requisite for a great quantity of possible applications. An adequate method to determine the chemical composition, as complete as possible, must be performed. Here we report the application of HPTLC fingerprint method on analysis of different neem products and derived extracts
HPTLC fingerprint analysis of plant staminal cell products
Full text linkUtilization of natural products is radically changing. Changes were mainly due to the outcome in the market of a plethora of new food supplements, and in particular those generally named botanicals for their common plant origin. The validation of these novel products needs powerful analytical devices tailored for the study of herbal extracts in order to assess composition and face their natural complexity as a resource. The last item is important and crucial for the capacity and utility of the analytical results that means that each product should be analyzed with the right approach. Having in mind these arguments, we selected HPTLC as useful tool for the analysis of products based on plant staminal (stem) cells. Nowadays these products, generally named bud-derivatives, are waiting scientific validation to obtain their own place into food supplements regulation, after gained that in the market. Our analyses, based on HPTLC fingerprints, were able to show bud-derivatives complex compositions that resulted very similar, but also in part different, to those of the corresponding leaf hydro-alcoholic extract
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