Caseinolytic activity of fruit extract from Opuntia ficus-indica on bovine, caprine, and ovine sodium caseinates

The rates and extents of hydrolysis of alpha(S)- and beta-caseins from bovine, caprine, and ovine sodium caseinates produced by an enzymatic extract of the fruit of Opuntia ficus-indica, (L.) Miller were evaluated and compared with those produced by a commercial animal rennet. A mechanistic model based on a pseudo-first-order enzymatic reaction, in the presence of first-order deactivation of the enzyme, was postulated and successfully fitted to the experimental data. The animal rennet exhibited higher enzymatic efficiency than the fruit extract, irrespective of the source (i.e., bovine, caprine, or ovine) and the type (i.e., alpha(S)- or beta-casein) of substrate. The enzymatic efficiency (k(cat)/K(m)) for alpha(S)-casein ranged from 72 to 220 and from 43 to 65 L g(-1) h(-1), and for beta-casein from 242 to 742 and from 55 to 164 L g(-1) h(-1), for the animal rennet and the enzymatic extract of O. ficus-indica, respectively. Finally, it was observed that beta-casein from caprine and ovine caseinates was degraded by O. ficus-indica faster than its alpha(S) counterpart, but the reverse was observed for bovine caseinate.     

Expression of a fungal hydrophobin in the Saccharomyces cerevisiae cell wall: effect on cell surface properties and immobilization

The aim of this work was to modify the cell surface properties of Saccharomyces cerevisiae by expression of the HFBI hydrophobin of the filamentous fungus Trichoderma reesei on the yeast cell surface. The second aim was to study the immobilization capacity of the modified cells. Fusion to the Flo1p flocculin was used to target the HFBI moiety to the cell wall. Determination of cell surface characteristics with contact angle and zeta potential measurements indicated that HFBI-producing cells are more apolar and slightly less negatively charged than the parent cells. Adsorption of the yeast cells to different commercial supports was studied. A twofold increase in the binding affinity of the hydrophobin-producing yeast to hydrophobic silicone-based materials was observed, while no improvement in the interaction with hydrophilic carriers could be seen compared to that of the parent cells. Hydrophobic interactions between the yeast cells and the support are suggested to play a major role in attachment. Also, a slight increase in the initial adsorption rate of the hydrophobin yeast was observed. Furthermore, due to the engineered cell surface, hydrophobin-producing yeast cells were efficiently separated in an aqueous two-phase system by using a nonionic polyoxyethylene detergent, C(12-18)EO(5).     

Hantavirus pulmonary syndrome in Uberaba,Minas Gerais,Brazil

This report describes the epidemiological and clinical-evolutive characteristics of eight patients with hantavirus pulmonary syndrome (HPS) in Uberaba, Minas Gerais, Brazil. A positive history of contact with rodents was present in 100% of the cases. The time between the onset of symptoms and hospital care was, on average, 3.6 days. All patients showed clinical and laboratory findings suggestive of HPS. Elevated urea and creatinine levels were observed in 6 (75%) cases, PO2 was < 60 mmHg in 100% of the cases, and a chest X-ray demonstrated a bilateral interstitial-alveolar infiltrate. The diagnosis was confirmed by the detection of IgM antibodies against Sin Nombre virus by ELISA. Three patients died as a direct consequence of HPS.     

Embryo recovery and pregnancy rates after the delay of ovulation and fixed time insemination in superstimulated beef cows

The aim of this study was to evaluate the effect of delaying ovulation subsequent to superstimulation of follicular growth in beef cows (Bos indicus) on embryo recovery rates and the capacity of embryos to establish pregnancies. Ovulation was delayed by three treatments using either progesterone (CIDR-B) or a GnRH agonist (deslorelin). Multiparous Nelore cows (n = 24) received three of four superstimulation treatments in an incomplete block design (n = 18 per group). Cows in Groups CTRL, P48 and P60 were treated with a CIDR-B device plus estradiol benzoate (EB, 4 mg, i.m.) on Day-5, while cows in Group D60 were implanted with deslorelin on Day-7. Cows were superstimulated with FSH (Folltropin-V, 200 mg), from Day 0 to 3, using twice daily injections in decreasing amounts. All cows were treated with a luteolytic dose of prostaglandin on Day 2 (08:00 h). CIDR-B devices were removed as follows: Group CTRL, Day 2 (20:00 h); Group P48, Day 4 (08:00 h); Group P60, Day 4 (20:00 h). Cows in Group CTRL were inseminated at 10, 20 and 30 h after first detected estrus. Ovulation was induced for cows in Group P48 (Day 4, 08:00 h) and Groups P60 and D60 (Day 4, 20:00 h) by injection of LH (Lutropin, 25 mg, i.m.), and these cows were inseminated 10 and 20 h after treatment with LH. Embryos were recovered on Days 11 or 12, graded and transferred to synchronized recipients. Pregnancies were determined by ultrasonography around Day 100. Data were analyzed by mixed procedure, Kruskal-Wallis and Chi-square tests. The number of ova/embryos, transferable embryos (mean +/- SEM) and pregnancy rates (%) were as follows, respectively: Group CTRL (10.8+/-1.8, 6.1+/-1.3, 51.5), P48 (12.6+/-1.9, 7.1+/-1.0, 52.3), P60 (10.5+/-1.6, 5.7+/-1.3, 40.0) and D60 (10.3+/-1.7, 5.0+/-1.2, 50.0). There were no significant differences among the groups (P > 0.05). It was concluded that fixed time AI in association with induced ovulation did not influence embryo recovery. Furthermore, pregnancy rates in embryos recovered from cows with delayed ovulation were similar to those in embryos obtained from cows treated with a conventional superstimulation protocol.     

Genome-wide nuclear morphology screen identifies novel genes involved in nuclear architecture and gene-silencing in Saccharomyces cerevisiae

Organisation of the cell nucleus is crucial for the regulation of gene expression but little is known about how nuclei are structured. To address this issue, we designed a genomic screen to identify factors involved in nuclear architecture in Saccharomyces cerevisiae. This screen is based on microscopic monitoring of nuclear pore complexes and nucleolar proteins fused with the green fluorescent protein in a collection of approximately 400 individual deletion mutants. Among the 12 genes identified by this screen, most affect both the nuclear envelope and the nucleolar morphology. Corresponding gene products are localised preferentially to the nucleus or close to the nuclear periphery. Interestingly, these nuclear morphology alterations were associated with chromatin-silencing defects. These genes provide a molecular context to explore the functional link between nuclear architecture and gene silencing.     

Bacteriocin production by spray-dried lactic acid bacteria

AIMS: Cell survival and antagonistic activity against Listeria innocua, Listeria monocytogenes and Staphylococcus aureus were investigated after spray-drying three bacteriocin-producing strains of lactic acid bacteria: Carnobacterium divergens, Lactobacillus salivarius and Lactobacillus sakei. METHODS AND RESULTS: Bacterial cell concentrates were spray-dried and stored at 4 degrees C and 18 degrees C and 0.3% ERH (equilibrium relative humidity). Enumeration and antagonistic activity were evaluated before and after spray-drying and at regular intervals during storage. CONCLUSIONS: A higher survival rate was obtained when survival was performed at 4 degrees C. With the exception of Carnobacterium divergens which lost the inhibitory activity against Staph. aureus after drying, antagonistic production was not affected by the process nor by the storage. Of the three species studied, Lact. salivarius showed the highest resistance to the spray-drying and storage processes. SIGNIFICANCE AND IMPACT OF THE STUDY: Spray-drying is a potentially useful process for large scale production of dried powders containing viable organisms with antagonistic activity against pathogens.     

Cardioprotective effects of phosphoramidon on myocardial structure and function in murine Chagas' disease

Chagas' disease is an important cause of cardiomyopathy. Endothelin-1, a vasoactive peptide has been implicated in the pathogenesis of chagasic cardiomyopathy. C57BL/6 x 129sv and CD1 mice were thus, infected with trypomastigotes of Trypanosoma cruzi (Brazil strain) and these infected mice were compared with infected mice treated with phosphoramidon. This compound inhibits endothelin-converting enzyme and neutral endopeptidases and does not affect the growth of the parasite in culture. Phosphoramidon was given in a dose of 10mg/kg for the initial 15 days post-infection None of the C57Bl/6 x 129sv mice died as a result of infection. However, there was marked myocardial inflammation and fibrosis in infected, untreated mice. The hearts of the infected, phosphoramidon-treated mice showed significantly less pathology. Cardiac magnetic resonance imaging of infected mice revealed right ventricular dilation that was less severe in those treated with phosphoramidon. Phosphoramidon-treated CD1 mice survived the acute infection. Transthoracic echocardiography demonstrated left ventricular dilation and reduced percent fractional shortening and relative wall thickness. These alterations were also attenuated as a result of phosphoramidon treatment. These data suggest that endothelin-1 contributes to the pathogenesis of chagasic cardiomyopathy and interventions that inhibit the synthesis of endothelin-1 and/or neutral endopeptidase might have a protective effect on myocardial structure and function in murine Chagas' disease.     

Expression and purification of the recombinant ConBr (Canavalia brasiliensis lectin) produced in Escherichia coli cells

ConBr, a D-glucose/D-mannose-specific lectin from Canavalia brasiliensis seeds, was produced in Escherichia coli from a (c)DNA clone subcloned to pET15b expression vector. The recombinant lectin (rConBr) was purified by one-step immobilized metal-affinity chromatography using an amino-terminal hexahistidine tag. By SDS-PAGE and Western blot, rConBr was highly pure with an apparent molecular mass of 37 kDa. N-terminal sequence analysis revealed a single sequence, confirming the identity of the expressed protein as the pre-pro-ConBr.     

Isolation and partial characterisation of a protein from buck seminal plasma (Capra hircus), homologous to spermadhesins

Spermadhesins are a family of secretory proteins expressed in the male genital tract of pig, horse and bull. Their function and structure have been widely studied, especially those isolated from boar. However, there are no data concerning spermadhesins isolated from buck. Buck seminal plasma was collected and subjected to ion exchange chromatography on DEAE-Sephacel column followed by chromatography in a C18 column coupled to a HPLC system. The purification of the protein was determined by SDS-PAGE and MALDI-TOF analysis exhibiting a molecular mass of 12.5 KDa and showed to be structurally homologous to spermadhesins from boar and stallion.