g-irradiation and thermal treatments have been used to produce sterilized cross-linked films. Formulations containing variable concentrations of calcium caseinate and whey proteins (whey protein isolate (WPI) and commercial whey protein concentrate) or mixture of soya protein isolate (SPI) with WPI was investigated on the physico-chemical properties of these films. Results showed that the mechanical properties of cross-linked films improved significantly the puncture strength for all types of films. Size-exclusion chromatography showed for no cross-linked proteins, a molecular mass of around 40 kDa. The soluble fractions of the cross-linked proteins molecular distributions were between 600 and 3800 kDa. g-irradiation seems to modify to a certain extent the conformation of proteins which will adopt structures more ordered and more stable, as suggested by X-ray diffraction analysis. Microstructure observations showed that the mechanical characteristics of these films are closely related to their microscopic structure. Water vapor permeability of films based on SPI was also significantly decreased when irradiated. Microbial resistance was also evaluated for cross-linked films. Results showed that the level of biodegradation of cross-linked films was 36% after 60 d of fermentation in the presence of Pseudomonas aeruginosa. r

An economic ferulic acid recovery from biomass via biological methods is of interest for a number of reasons. Ferulic acid is a precursor to vanillin synthesis. It is also a known antioxidant with potential food and medical applications. Despite its universal presence in all plant cell wall material, the complex structure of the plant cell wall makes ferulic acid recovery from biomass a challenging bioprocess. Previously, without pretreatment, very low (3-13%) recovery of ferulic acid from corn residues was achieved. We report here the discovery of a filamentous fungus Neosartorya spinosa NRRL185 capable of producing a full complement of enzymes to release ferulic acid and the development of an enzymatic process for a complete recovery of ferulic acid from corn bran and corn fibers. A partial characterization of the extracellular proteome of the microbe revealed the presence of at least seven cellulases and hemicellulases activities, including multiple iso-forms of xylanase and ferulic acid esterase. The recovered ferulic acid was bio-converted to vanillin, demonstrating its potential application in natural vanillin synthesis. The enzymatic ferulic acid recovery accompanied a significant release of reducing sugars (76-100%), suggesting much broader applications of the enzymes and enzyme mixtures from this organism.

No abstract

The association of carboxymethyl starch (CMS) and alginate is proposed as a novel matrix for the entrapment of bioactive agents in microspheres affording their protection against gastrointestinal degradation. In this study, the enzyme diamine oxidase (DAO) from white pea (Lathyrus sativus) was immobilized by inclusion in microspheres formed by ionotropic gelation of CMS/alginate by complexation with Ca2+. The association of CMS to alginate generated a more compact structure presenting a lesser porosity, thus decreasing the access of gastric fluid inside the microspheres and preventing the loss of entrapped enzyme. Moreover, the immobilized enzyme remained active and was able to oxidize the polyamine substrates even in the presence of degrading proteases of pancreatin. The inclusion yield in terms of entrapped protein was of about 82%–95%. The DAO entrapped in calcium CMS/alginate beads retained up to 70% of its initial activity in simulated gastric fluid (pH 2.0). In simulated intestinal fluid (pH 7.2) with pancreatin, an overall retention of 65% of activity for the immobilized DAO was observed over 24 H, whereas in similar conditions the free enzyme was totally inactivated. Our project proposes the vegetal DAO as an antihistaminic agent orally administered to treat food histaminosis and colon inflammation.

No abstract

Background: The 5-HT1B receptor (5-HT1BR) agonist, CP94253, enhances cocaine intake during maintenance of self-administration (SA) but attenuates intake after 21 days of forced abstinence in male rats. Aims: We examined whether CP94253 attenuates cocaine intake in female rats after a period of abstinence, and if these attenuating effects persist or revert to enhancing cocaine intake during resumption (i.e. relapse) of daily cocaine SA. Methods: Male and female rats trained to lever press on a fixed ratio 5 schedule of cocaine reinforcement underwent ⩾21 days of forced abstinence. They were then tested for the effects of CP94253 (5.6 mg/kg, SC) or vehicle on cocaine SA. During the test session, rats had 1-h access to the training dose of cocaine (0.75 mg/kg, IV) followed by 1-h access to a lower cocaine dose (0.075 mg/kg, IV). Rats then resumed cocaine SA for 15 days to mimic relapse and were retested as done previously. Subsequently, rats underwent abstinence again (21–60 days) and were tested for CP94253 effects on locomotion and cue reactivity (i.e. responding for light/tone cues previously paired with cocaine infusions). Results: Regardless of sex, CP94253 decreased cocaine intake after abstinence and during resumption of SA and decreased cue reactivity while having no effect on locomotion. Conclusions: CP94253 decreases cocaine intake and cocaine seeking in both males and females even after resumption of cocaine SA. These findings suggest that the inhibitory effects of CP94253 observed after abstinence are long-lasting, and therefore, 5-HT1BR agonists may have clinical efficacy as anti-relapse medications for cocaine use disorders.

Erms are proteins that methylate the adenine (A2058) in Escherichia coli 23S rRNA, which results in resistance to macrolide, lincosamide, and streptogramin B antibiotics. In a previous report, ErmN appeared to be more susceptible to contaminating proteases in DNase I. To determine the underlying mechanism, cleavage with chymotrypsin over time was investigated. ErmN possesses unusually high-susceptibility recognition site (F45) as evidenced by a band (band 1) that represented greater than 80% of the total band intensity at 30 s. The exposure rate of the hydrophobic core was more than 67-fold and 104-fold faster in ErmN than those in ErmS and ErmE, respectively. After cleavage at F45, some of the hydrophobic interactions were disrupted. Further digestion of band 1 occurred through the exposed F163 with a half-life of 3.18 min. After 30 min, less than 1% of ErmN remained. On the basis of the structure of ErmC′, the location of F45 was presumed to be in an α helix at the bottom of a cavity. Both substitution of most common amino acids such as isoleucine, valine, or leucine with phenylalanine (ErmH, ErmI, ErmN, and ErmZ out of the 37 known Erms) and the apparent added flexibility, which could result from the additional loop region attached to phenylalanine that is four to nine amino acids longer (ErmI, ErmN, and ErmZ, which form one cluster in the phylogenetic tree), could cause unusually high susceptibility. The unexpectedly high susceptibility among the homologous proteins could indicate that caution should be taken not to misinterpret the observations when conducting any procedure in which protease or protease contamination is involved.

No abstract