Aspartic proteinases (AP) play major roles in physiologic and pathologic scenarios in a wide range of organisms from vertebrates to plants or viruses. The present work deals with the purification and characterisation of four new APs from the cardoon Cynara cardunculus L., bringing the number of APs that have been isolated, purified and biochemically characterised from this organism to nine. This is, to our knowledge, one of the highest number of APs purified from a single organism, consistent with a specific and important biological function of these protein within C. cardunculus. These enzymes, cardosins E, F, G and H, are dimeric, glycosylated, pepstatin-sensitive APs, active at acidic pH, with a maximum activity around pH 4.3. Their primary structures were partially determined by N- and C-terminal sequence analysis, peptide mass fingerprint analysis on a MALDI-TOF/TOF instrument and by LC-MS/MS analysis on a Q-TRAP instrument. All four enzymes are present on C. cardunculus L. pistils, along with cyprosins and cardosins A and B. Their micro-heterogeneity was detected by 2D-electrophoresis and mass spectrometry. The enzymes resemble cardosin A more than they resemble cardosin B or cyprosin, with cardosin E and cardosin G being more active than cardosin A, towards the synthetic peptide KPAEFF(NO(2))AL. The specificity of these enzymes was investigated and it is shown that cardosin E, although closely related to cardosin A, exhibits different specificity.
In this study we assessed the occurrence, diversity and conjugative potential of plasmids in integron‐carrying Aeromonas and Enterobacteriaceae from wastewaters. Sixty‐six strains were included as donors in mating assays using rifampicin‐resistant Escherichia coli and Pseudomonas putida recipient strains. The diversity of plasmids from donors and transconjugants (resistant to tetracycline or streptomycin) was evaluated by restriction analysis and replicon typing targeting 19 incompatibility groups. Restriction patterns revealed a diverse plasmid pool present in these strains. Plasmids were assigned to FrepB (Aeromonas salmonicida, Aeromonas veronii, Aeromonas sp., E. coli, Enterobacter sp.), FIC (A. salmonicida, Aeromonas sp.), FIA (Shigella sp.), I1 (A. veronii, Aeromonas sp., E. coli), HI1 (E. coli) and U (Aeromonas media) replicons. Nevertheless, 50% of the plasmids could not be assigned to any replicon type. Among integron‐positive transconjugants, FrepB, I1 and HI1 replicons were detected. Results showed that wastewaters enclose a rich plasmid pool associated with integron‐carrying bacteria, capable of conjugating to different bacterial hosts. Moreover, replicons detected in this study in Aeromonas strains expand our current knowledge of plasmid diversity in this genus.
-Background -Postoperative liver failure consequent to insufficiency of remnant liver is a feared complication in patients who underwent extensive liver resections. To induce rapid and significant hepatic hypertrophy, associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been recently developed for patients which tumor is previously considered unresectable. Aim -To present the Brazilian experience with ALPPS approach. Method -Were analyzed 39 patients who underwent hepatic resection using ALPPS in nine hospitals. The procedure was performed in two steps. The first operation was portal vein ligation and in situ splitting. In the second operation the right hepatic artery, right bile duct and the right hepatic vein were isolated and ligated. The extended right lobe was removed. There were 22 male (56.4%) and 17 female (43.6%). At the time of the first operation, the median age was 57.3 years (range: 20-83 years). Results -The most common indication was liver metastasis in 32 patients (82.0%), followed by cholangiocarcinoma in three (7.7%). Two patients died (5.2%) during this period and did not undergo the second operation. The mean interval between the first and the second operation was 14.1 days (range: 5-30 days). The volume of the left lateral segment of the liver increased 83% (range 47-211.9%). Significant morbidity after ALPPS was seen in 23 patients (59.0%). The mortality rate was 12.8% (five patients). Conclusion -The ALPPS approach can enable resection in patients with lesions previously considered unresectable. It induces rapid liver hypertrophy avoiding liver failure in most patients. However still has high morbidity and mortality.RESUMO -Racional -Insuficiência hepática pós-operatória devido à remanescente hepático pequeno tem sido complicação temida em pacientes que são submetidos à ressecção hepática extensa. A ligadura da veia porta associada à bipartição do fígado para hepatectomia em dois estágios (ALPPS) foi desenvolvida recentemente com a finalidade de induzir rápida e significante regeneração do fígado para pacientes em que o tumor é previamente considerado irressecável. Objetivo -Apresentar a experiência brasileira com o ALPPS. Método -Foram analisados 39 pacientes submetidos ao procedimento ALPPS em nove hospitais. Ele foi realizado em duas etapas. A primeira operação consistiu em ligadura do ramo direito da veia porta e bipartição hepática. Na segunda, os ramos direito da artéria hepática, via biliar e veia hepática foram ligados e o lobo hepático direito estendido foi removido.
The structural stability of cardosin A, a plant aspartic proteinase (AP) from Cynara cardunculus L., has been investigated by high-sensitivity differential scanning calorimetry, intrinsic fluorescence and circular dichroism spectroscopy, and enzymatic activity assays. Even though the thermal denaturation of cardosin A is partially irreversible, valid thermodynamic data can be obtained within a wide pH region. Also, although cardosin A is a heterodimeric enzyme its thermal denaturation occurs without simultaneous dissociation to unfolded monomers. Moreover, in the 3-7 pH region the excess heat capacity can be deconvoluted into two components corresponding to two elementary two-state transitions, suggesting that the two polypeptide chains of cardosin A unfold independently. Detailed thermodynamic and structural investigations of cardosin A at pH = 5.0, at which value the enzyme demonstrates maximum stability and enzymatic activity, revealed that after thermal denaturation the polypeptide chains of this protein retain most of their secondary structure motifs and are not completely hydrated.
Platforms with liquid cores are extensively explored as cell delivery vehicles for cell-based therapies and tissue engineering. However, the recurrence of synthetic materials can impair its translation into the clinic. Inspired by the adhesive proteins secreted by mussels, liquefied capsule is developed using gelatin modified with hydroxypyridinones (Gel-HOPO), a catechol analogue with oxidant-resistant properties. The protein-based liquefied macrocapsule permitted the compartmentalization of living cells by an approachable and non-time-consuming methodology resorting to i) superhydrophobic surfaces as a processing platform of hydrogel beads, ii) gelation of gelatin at temperatures < 25°C, iii) iron coordination of the hydroxypyridinone (HOPO) moieties at physiological pH, and iv) core liquefaction at 37°C. With the design of a proteolytically degradable shell, the possibility of encapsulating human adipose-derived mesenchymal stem cells (hASC) with and without the presence of polycaprolactone microparticles ( PCL) is evaluated. Showing prevalence toward adhesion to the inner shell wall, hASC formed a monolayer evidencing the biocompatibility and adequate mechanical properties of these platforms for proliferation, diminishing the need for PCL as a supporting substrate. This new protein-based liquefied platform can provide biofactories devices of both fundamental and practical importance for tissue engineering and regenerative medicine or in other biotechnology fields.
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