259 research outputs found
Molecular farming of human tissue transglutaminase in tobacco plants
In this study we have utilized Nicotiana tabacum with a molecular farming purpose in attempt of producing transgenic plants expressing the human tissue transglutaminase (htTG). Three plant expression constructs were used enabling targeting and accumulation of the recombinant protein into the plant cell cytosol (cyto), the chloroplasts (chl) and the apoplastic space (apo). Analysis of transgenic T(0) plants revealed that recombinant htTG was detectable in all three transgenic lines and the accumulation levels were in a range of 18-75 mu g/g of leaf material. In the T(1) generation, the recombinant htTG was still expressed at high level and a significant catalytic activity was detected into the leaf protein extracts. Southern blot analyses revealed that apo and chl plants of T(1) generation possess a high copy number of the recombinant htTG in their genome, while the cyto plants carry a single copy
Immobilization of two endoglucanases from different sources
Cellulases are a important family of
hydrolytic enzymes which catalyze the bond of cellulose
and other related cello-oligosaccharide derivates.
Industrial applications require enzymes highly stable and
economically viable in terms of reusability. These costs
can be reduced by immobilizing the cellulases, offering a
potential solution through enzyme recycling and easy
recovery. The covalent immobilization of enzymes is
reported here: one is commercial cellulase from
Aspergillus niger and other one is recombinant enzyme,
named CelStrep it because was isolated from a new
cellulolytic strain, Streptomyces sp. G12,. The optimal pH
for binding is 4.6 for both cellulases and the optimal
enzyme concentrations are 1 mg/mL and 5 mg/mL
respectively. The support for immobilization is a
poliacrylic matrix. Experiments carried out in this work
show positive results of enzyme immobilization in terms
of efficiency and stability and confirm the economic and
biotechnical advantages of enzyme immobilization for a
wide range of industrial applications
Structure and in vitro digestibility of grass pea (Lathyrus sativus L.) flour following transglutaminase treatment
The impact of transglutaminase (TG) modification on microstructure and in vitro protein and starch digestibility of grass pea flour was investigated. Results demonstrated that grass pea flour proteins act as effective substrate of TG. Microstructural results showed that the addition of TG produced a more compact structure likely due to TG-catalyzed heteropolymers. Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: grass pea flour incubated in the absence of TG>grass pea flour incubated in the presence of TG>raw flour. The TG-catalyzed heteropolymers were easily digested as demonstrated by in vitro oral and gastric digestion carried out under physiological conditions. Therefore, TG-modified grass pea flour can be considered as a new source of starch and proteins suitable for feeding a large spectrum of population
‘L’operazione militare israeliana “Guardiano delle mura” tra antinomie giuridiche e cicli di violenza armata. Note per un’interpretazione sistematica del crimine di guerra di attacco ‘deliberato’ a strutture civili’
Transglutaminase-catalyzed site-specific glycosidation of catalase with aminated dextran
An enzymatic approach, based on a transglutaminase-catalyzed coupling reaction, was investigated to modify bovine liver
catalase with an end-group aminated dextran derivative. We demonstrated that catalase activity increased after enzymatic glycosidation
and that the conjugate was 3.8-fold more stable to thermal inactivation at 55 ◦C and 2-fold more resistant to proteolytic
degradation by trypsin. Moreover, the transglutaminase-mediated modification also improved the pharmacokinetics behavior
of catalase, increasing 2.5-fold its plasma half-life time and reducing 3-fold the total clearance after its i.v. administration in
rats
Putrescine-polysaccharide conjugate as transglutaminase substrates and their possible use in producing crosslinked films
Putrescine (1,4-diaminobutane) was covalently linked to alginate and low-methoxyl pectin to synthesize new aminated polysaccharides. Both putrescine-pectin and -alginate conjugates, although the latter at higher concentrations, were found to be able to act as effective acyl acceptor transglutaminase substrates in vitro using both dimethylated casein and soy flour proteins as acyl donors. Monodansylcadaverine, a well known acyl acceptor transglutaminase substrate, dose-dependently counteracted the covalent binding of the aminated polysaccharides to the proteins. Putrescine-pectin conjugate was also tested to prepare, in combination with soy flour proteins, edible films in the presence of purified microbial transglutaminase. Characterization of the enzymatically crosslinked films showed a significant decreased water vapor permeability, with respect to the ones obtained with non-aminated pectin in the presence of transglutaminase, as well as improved mechanical properties, such as high extensibility. Possible biotechnological applications of hydrocolloid films containing putrescine-polysaccharide derivatives enzymatically crosslinked to proteins were suggested
Stabilization of Charged Polysaccharide Film Forming Solution by Sodium Chloride: Nanoparticle Z-Average and Zeta-Potential Monitoring
Different natural biopolymers are becoming the issue of an
expanding number of studies reporting their potential applications
in food, pharmaceutical and cosmetic technologies, as well as in
tissues engineering . In this respect, the utilization of charged
polysaccharides like chitosan (CH) or pectin (PEC) appears to be one
of the most interesting way in manufacturing of biodegradable new
materials
Biodegradable polymeric micro/Nano-structures with intrinsic antifouling/antimicrobial properties: Relevance in damaged skin and other biomedical applications
Bacterial colonization ofimplanted biomedical devicesis themain cause of healthcare-associated infections, estimated to be 8.8 million per year in Europe. Many infections originate from damaged skin, which lets microorganisms exploit injuries and surgical accesses as passageways to reach the implant site and inner organs. Therefore, an effective treatment of skin damage is highly desirable for the success of many biomaterial-related surgical procedures. Due to gained resistance to antibiotics, new antibacterial treatments are becoming vital to control nosocomial infections arising as surgical and post-surgical complications. Surface coatings can avoid biofouling and bacterial colonization thanks to biomaterial inherent properties (e.g., super hydrophobicity), specifically without using drugs, which may cause bacterial resistance. The focus of this review is to highlight the emerging role of degradable polymeric micro- and nano-structures that show intrinsic antifouling and antimicrobial properties, with a special outlook towards biomedical applications dealing with skin and skin damage. The intrinsic properties owned by the biomaterials encompass three main categories: (1) physical-mechanical, (2) chemical, and (3) electrostatic. Clinical relevance in ear prostheses and breast implants is reported. Collecting and discussing the updated outcomes in this field would help the development of better performing biomaterial-based antimicrobial strategies, which are useful to prevent infections
The crosstalk between FGF21 and GH leads to weakened GH receptor signaling and IGF1 expression and is associated with growth failure in very preterm infants.
BACKGROUND: Fibroblast growth factor 21 (FGF21) is an essential metabolic regulator that adapts to changes in nutritional status. Severe childhood undernutrition induces elevated FGF21 levels, contributing to growth hormone (GH) resistance and subsequent linear growth attenuation potentially through a direct action on chondrocytes. METHODS: In this study, we assessed expression of the components of both GH and FGF21 pathways in rare and unique human growth plates obtained from children. Moreover, we investigated the mechanistic interplay of FGF21 on GH receptor (GHR) signaling in a heterologous system. RESULTS: Chronic FGF21 exposure increased GH-induced GHR turnover and SOCS2 expression, leading to the inhibition of STAT5 phosphorylation and IGF-1 expression. The clinical significance of FGF21 signaling through GH receptors was tested in nutritionally driven growth failure seen in very preterm (VPT) infants right after birth. VPT infants display an immediate linear growth failure after birth followed by growth catch-up. Consistent with the in vitro model data, we show that circulating FGF21 levels were elevated during deflection in linear growth compared to catch-up growth and were inversely correlated with the length velocity and circulating IGF1 levels. CONCLUSIONS: This study further supports a central role of FGF21 in GH resistance and linear growth failure and suggests a direct action on the growth plate
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