54 research outputs found
Effect of period of milk production and ripening on quality traits of Asiago cheese
After 6 and 12 months of ripening, samples of Asiago d'Allevo were analyzed for quality traits. Cheeses were produced during 3 periods using milk from cows fed a total mixed ration (TMR, May) or grazing on alpine pasture (AG) in early (July) and late (Sept.) summer. Data were submitted to ANOVA considering ripening, milk production period and farm as main effects, and whole cheese weight as covariate. During ripening, pH of AGcheese was significantly lower than that of TMR-cheese; crude fat and protein significantly increased. According to period, July-samples showed the significantly lowest value of dry matter (DM), maybe due to a lower crude fat content; however, variability in skimming method could have altered proximate composition. No texture differences were found, although increasing weight of whole cheese significantly reduced max shear force as result of a lower DM content. Lightness (L*) and yellowness (b*) significantly decreased during ripening. AG feeding system caused a lower L* and higher b* than TMR one, probably as a consequence of a different amount of milk pigments. Cheese varied also within AG season: Sept.-samples showed the lowest L* value and the highest b*
PKA regulatory subunits mediate synergy among conserved G-protein-coupled receptor cascades
G-protein-coupled receptors sense extracellular chemical or physical stimuli and transmit these signals to distinct trimeric G-proteins. Activated Gα-proteins route signals to interconnected effector cascades, thus regulating thresholds, amplitudes and durations of signalling. Gαs- or Gαi-coupled receptor cascades are mechanistically conserved and mediate many sensory processes, including synaptic transmission, cell proliferation and chemotaxis. Here we show that a central, conserved component of Gαs-coupled receptor cascades, the regulatory subunit type-II (RII) of protein kinase A undergoes adenosine 3′-5′-cyclic monophosphate (cAMP)-dependent binding to Gαi. Stimulation of a mammalian Gαi-coupled receptor and concomitant cAMP-RII binding to Gαi, augments the sensitivity, amplitude and duration of Gαi:βγ activity and downstream mitogen-activated protein kinase signalling, independent of protein kinase A kinase activity. The mechanism is conserved in budding yeast, causing nutrient-dependent modulation of a pheromone response. These findings suggest a direct mechanism by which coincident activation of Gαs-coupled receptors controls the precision of adaptive responses of activated Gαi-coupled receptor cascades
Control of mitochondria dynamics and oxidative metabolism by cAMP, AKAPs and the proteasome.
Mitochondria are highly specialized organelles and major players in fundamental aspects of cell physiology. In yeast, energy metabolism and coupling of mitochondrial activity to growth and survival is controlled by the protein kinase A pathway. In higher eukaryotes, modulation of the so-called A-kinase anchor protein (AKAP) complex regulates mitochondrial dynamics and activity, adapting the oxidative machinery and the metabolic pathway to changes in physiological demand. Protein kinases and phosphatases are assembled by AKAPs within transduction units, providing a mechanism to control signaling events at mitochondria and other target organelles. Ubiquitin-mediated proteolysis of signal transducers and effectors provides an additional layer of complexity in the regulation of mitochondria homeostasis. Genetic evidence indicates that alteration of one or more components of these biochemical pathways leads to mitochondrial dysfunction and human diseases. In this review, we focus on the emerging role of AKAP scaffolds and the proteasome pathway in the control of oxidative metabolism, organelle dynamics and the mitochondrial signaling network. These aspects are crucial elements for maintaining a proper energy balance and cellular lifespan
Evaluation of fast PCR reagents for rapid and sensitive detection of human herpesvirus 8.
The potential advantage of using fast PCR to detect human herpesvirus 8 (HHV-8) was tested by running
a rapid cycling protocol (5 s-steps) in one standard and two fast ramping thermal cyclers to evaluate
the performance of 8 different fast reagents. Under this extremely short time profile, assay sensitivity
comparable to that of the original protocol was maintained using fast reagents from five suppliers. Reproducibility
was higher using fast ramping thermal cyclers, suggesting that fast chemistry may be better
matched with advanced instruments. Few fast reagents showed a 2-log-increase in sensitivity and good
consistency, that allowed the substitution of the standard nested PCR method with the fast, single round
technique. Overall, these studies indicate that some of the fast reagents tested may be used to perform a
highly sensitive and reproducible HHV-8 detection with a considerable time saving
Test in vitro per Valutare l'attivit\ue0 antiossidante e antimicrobica di un estratto vegetale
The results of two tests in vitro to evaluate
antioxidant and antimicrobial activity of
grape marc extract are presented. Bovine
lymphocytes are incubated for 24 hours in
presence of various extract concentrations (5
to 10.5 mg/mL) and subsequently stressed
by addition of 15 \u3bcM (CuOH) hydroperoxide
cumene solution. The intracellular production
of ROS (reactive oxygen substances) are
detected by partially modified method of
DCF-DA (2,7 dichlorofluorescein diacetate),
proposed by Rosenkranz et al. (1992).
The antimicrobial activity test is carried
out on agar plate inoculated by Bacillus
stearothermophilus var. calidolactis C 953
spore. The appearance of a halo of inhibition
after 24 hours of incubation confirmed the
extract antimicrobial activity
Protein-tyrosine phosphatase PTPD1 regulates focal adhesion kinase autophosphorylation and cell migration
PTPD1 is a cytosolic nonreceptor tyrosine phosphatase and a positive regulator of the Src-epidermal growth factor transduction pathway. We show that PTPD1 localizes along actin filaments and at adhesion plaques. PTPD1 forms a stable complex via distinct molecular modules with actin, Src tyrosine kinase, and focal adhesion kinase (FAK), a scaffold protein kinase enriched at adhesion plaques. Overexpression of PTPD1 promoted cell scattering and migration, short hairpin RNA-mediated silencing of endogenous PTPD1, or expression of PTPD1 mutants lacking either catalytic activity (PTPD1(C1108S)) or the FERM domain (PTPD1(Delta 1-325)) significantly reduced cell motility. PTPD1 and Src catalytic activities were both required for epidermal growth factor-induced FAK autophosphorylation at its active site and for downstream propagation of ERK1/2 signaling. Our findings demonstrate that PTPD1 is a component of a multivalent scaffold complex nucleated by FAK at specific intracellular sites. By modulating Src-FAK signaling at adhesion sites, PTPD1 promotes the cytoskeleton events that induce cell adhesion and migration
Angiotensin-Converting Enzyme Inhibitory Activity of Water-Soluble Extracts of Asiago d’Allevo Cheese
The angiotensin-converting enzyme (ACE) inhibitory activity of water-soluble extracts
(WSE) from Asiago cheeses was assayed in two cheese production systems and with
different ripening times. The WSE were ultrafiltered through 10 kDa and 3 kDa cut-off
membranes to evaluate the ACE inhibitory activity of long and short peptides, respectively.
The cheese production systems had no significant effect on the ACE inhibitory activity,
whereas 6-month-old cheeses had higher inhibitory potency than the more ripened ones.
Moreover, the fraction containing peptides smaller than 3 kDa made a more considerable
contribution to ACE inhibitory activity than the fraction smaller than 10 kDa, suggesting an
inhibitory effect due to short peptides. The peptidic fraction was characterized using RPHPLC
coupled to mass spectrometric detection. Simulated gastrointestinal digestion was
carried out to evaluate the effects of digestive enzymes on the generation of bioactive
peptides, but this did not significantly affect the inhibitory activity
Expression of the ring ligase PRAJA2 in thyroid cancer
In thyroid cells, binding of TSH to its receptor increases cAMP levels, sustaining thyrocytes growth and hormone production. The main cAMP effector enzyme is protein kinase A (PKA). Praja2 is a widely expressed RING (Really Interesting New Gene) ligase, which degrades the regulatory subunits of PKA, thus controlling the strength and duration of PKA signaling in response to cAMP. Differentiated thyroid cancer expresses a functional TSH receptor, and its growth and progression are positively regulated by TSH and cAMP signaling
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