Miniature cheeses made with blends of chymosin and a vegetable rennet from flowers of Silybum marianum: Enzymatic characterization of the flower-coagulant peptidase

Binary blends of S. marianum–flower extract and chymosin, as coagulant preparations, enabled the manufacture of miniature cheeses with distinctive characteristics compared to those of chymosin-renneted cheeses. The physicochemical parameters, sensory attributes of the cheeses, and in-vitro water-soluble antioxidant activity were analyzed and compared to those properties obtained from control chymosin-renneted cheeses. The preponderant proteolytic constituent in the flower extract was isolated in a two-step-purification protocol. The thus purified aspartic peptidase was maximally active at acidic pHs and exhibited a preference for peptide bonds between hydrophobic residues. Enzymologic characterization revealed differences in the kinetic parameters and specificity compared to other enzymes employed, such as rennet. S. marianum–flower extract, as a source of peptidase with distinctive characteristics, is a suitable substitute for chymosin in miniature-cheese production. The addition of vegetable rennet contributed to the development of an intense aroma and conferred antioxidant activity to the cheeses and wheys.Fil: Colombo, Maria Laura. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Fernández, Agustina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Cimino, Cecilia Verónica. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; ArgentinaFil: Liggieri, Constanza Silvina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; ArgentinaFil: Bruno, Mariela Anahí. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; ArgentinaFil: Faro, Carlos. Universidad de Coimbra; PortugalFil: Veríssimo, Paula C.. Universidad de Coimbra; PortugalFil: Vairo Cavalli, Sandra Elizabeth. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Ligninolytic enzyme ability and potential biotechnology applications of the white-rot fungus Grammothele subargentea

8 páginas, 4 figuras, 2 tablas -- PAGS nros. 368-375To get a better insight into the ligninolytic system of Grammothele subargentea, extracellular ligninolytic enzyme activities and ability to degrade synthetic dyes as well as Eucalyptus globulus wood were assayed in cultures grown on an agar medium with Cu2+ or dyes and on E. globulus wood chips. Laccase was the only ligninolytic enzyme detected. The fungus was able to decolorize different dyes, being the highest levels of laccase activity in cultures with Brilliant Green. Cultures on wood showed both ligninolytic activity and degradative ability on lipophilic extractives. An extracellular laccase with pI 3.5 and maximal activity at pH 4.0 and 50–55 8C was detected on liquid cultures containing 0.6 mM Cu2+. The enzyme extract was stable at pH 6.0–7.0 and up to 60 8C. A laccase-mediator system using a G. subargentea laccase crude extract and 1- hydroxybenzotriazole as mediator improved the tensile strength of a paper from recycled high-kappa-number pulp. # 2008 Elsevier Ltd. All rights reservedThis work was supported by Fundacio´n Antorchas (Proy. 14188-64) Argentina, and Agencia Nacional de Promocio´n Cientı´fica y Tecnolo´gica (PICT 14- 06962, BID 1201/OC-AR, ANPCYT 13404 BID 1201/OCAR), Argentina.Peer reviewe

Bloodstream infections in patients living with HIV in the modern cART era

Abstract Retrospective multicentre study aiming at analysing the etiology, characteristics and outcome of bloodstream infections (BSI) in people living with HIV (PLWHIV) in an era of modern antiretroviral therapy. Between 2008 and 2015, 79 PLWHIV had at least 1 BSI, for a total of 119 pathogens isolated. Patients were mainly male (72.1%), previous intravenous drug users (55.7%), co-infected with HCV or HBV (58.2%) and in CDC stage C (60.8%). Gram-positive (G+) pathogens caused 44.5% of BSI, followed by Gram-negative (G−), 40.3%, fungi, 10.9%, and mycobacteria, 4.2%. Candida spp. and coagulase-negative staphylococci were the most frequent pathogens found in nosocomial BSI (17% each), while E.coli was prevalent in community-acquired BSI (25%). At the last available follow-up, (mean 3.2 ± 2.7 years) the overall crude mortality was 40.5%. Factors associated with mortality in the final multivariate analysis were older age, (p = 0.02; HR 3.8, 95%CI 1.2–11.7) CDC stage C (p = 0.02; HR 3.3, 95%CI 1.2–9.1), malignancies, (p = 0.004; HR 3.2, 95%CI 1.4–7.0) and end stage liver disease (p = 0.006; HR 3.4, 95%CI 1.4–8.0). In conclusion, the study found high mortality following BSI in PLWHIV. Older age, neoplastic comorbidities, end stage liver disease and advanced HIV stage were the main factors correlated to mortality

Bloodstream infections in patients living with HIV infection in the recent cART era: did something change?\u201d.

Background: In the modern combined antiretroviral therapy (cART) era, non-AIDS defining infections are becoming an increasing cause of hospitalization of people living with HIV (PLWHIV). The present study aims to investigate the current epidemiology and clinical characteristics of bloodstream infections (BSI) in HIV-positive patients. Material and Methods: Retrospective multicentre study conducted in 2008-2015, enrolling all PLWHIV>18 years who developed a BSI. Results: A total of 114 episodes of BSI were recorded in 75 PLWHIV, followed for a mean period of 2.7 \ub1 2.6 years. All patients were hospitalized. Forty-six episodes (40%) were nosocomial, with significantly longer hospital stay compared to community-acquired episodes (59, Q34-110, median days, p<0.0001). The majority of patients PLWHIV included in the study were male (73.3%), previous intravenous drug users (58.7%), co-infected with HCV or HBV (60.0%) and in CDC stage C (58.7%). Gram-positive (G+) pathogens caused 46.5% of BSI, followed by Gram-negative (G-), 42.1%, and fungi (F), 11.4%. G- were prevalent among community-acquired BSI (48.5% vs 32.6%), while G+ were more frequent in nosocomial infections (48% vs 46%). Despite numbers are low, F were more often seen in hospitalized patients (9 of 13 episodes, p=0.03). The most frequently isolated pathogen was E.coli (18%), followed by Streptococcus spp (15%) and S. aureus (12%). Candida spp and coagulase negative staphylococci were the two most frequent pathogens found in nosocomial BSI (17% each), while E.coli was prevalent in community-acquired BSI (27%). Median CD4+ count (cells/mm3) was 165 (62-278) in the global population, varying from 226 (102-299) in G-, 161 (61-256) in G+ and 62 (35-175) in F BSI (p = 0.03 for trend). Mortality was 7% within the first two weeks, 13% within 30 days, 24% within 6 months and 38% within 1 year. The higher mortality was found in fungal BSI: 23% within 30 days (vs 13% in G- and 11.3% in G+), 46.1% within 6 months (vs 21% in G- and 21% in G+) and 62% at 1 year (vs 35% in G- and 34% in G+). At the last available follow-up, the overall crude mortality was 76%. Median time to death from BSI was 231 days (43-438). Fungal etiology, number of previous episodes of BSI, advanced CDC stage and older age resulted significantly associated with higher mortality in univariable model. Only advanced CDC stage and older age remained in the multivariable model (HR 1.0 95%CI 1.0-1.1, p=0.01 and HR 3.7, 95%CI 1.5-9.1, p=0.005). Conclusions: The study found high frequency of nosocomial episodes and a higher than expected frequency of G- as etiology of community-acquired BSI, with E.coli as main causative agent overall. For the first time Candida spp. has been found to be the most frequent cause of nosocomial BSI in PLWHIV. Older age and advanced HIV stage are the main factors correlated to mortality in our population

Interfacial Properties of Nanoparticle-Surfactant Systems

The utilisation of solid micro/nanoparticles particles in association with surfactants represents an attractive route to control drop/bubble coalescence or liquid film stability in foam and emulsion technology. In fact, the transfer/attachment of nanoparticles to liquid interfaces, driven by their partial wettability, strongly modifies the mechanical properties of the interfacial layers. At large surface coverage, particles can build solid-like barriers to coalescence, such as particle networks, while at low surface coverage, small particles segregating at the interface may play a role more similar to surfactants, affecting equilibrium and dynamic interfacial tension. Surfactant adsorption at the particle surface can be utilised to control such situations, by tuning the hydrophilic/hydrophobic character of the particles and then their ability to form interfacial layers. For these mixed particle-surfactant systems interfacial properties, such as dynamic interfacial tension are still poorly investigated. These studies, however, can bring important information on the undergoing dynamic processes associated with particles and surfactant transfer and organisation at the interface and are essential to understand how to achieve film stabilisation by the smallest amount of particles or surfactant. Previous investigations [1.2] have shown the effectiveness of dilational rheology in providing a better comprehension of dynamic mechanisms occurring in the interfacial layer. In some cases, rheological studies allow in fact the equilibrium and kinetic parameters related to the structure of the particle layer and to the particle interaction to be accessed. Here, we summarise results obtained for interfacial layers containing silica or alumina nanoparticles, which can be utilized as stabilisers for foams and/or emulsions. Different degree of hydrophobicity and, consequently, different affinity with the water/oil interfaces is obtained by using specific anionic or cationic surfactants. The results for a particular arrangement with the surfactant soluble only in the oil phase and hydrophilic particles dispersed in the aqueous phase, where the surfactant-nanoparticle interaction occurs only at the interface, is also reported. [1]. F. Ravera, E. Santini, G. Loglio, M. Ferrari, L. Liggieri, J. of Physical Chemistry B, /10,, 19543. 2006. [2]. F. Ravera, M. Ferrari, L. Liggieri , G. Loglio, E. Santini, A. Zanobini, Colloids Surf A. 323,, 99-108, 2006 1