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Fungi, with all their biological and enzymatic qualities, could have great potential being implemented in industrial processes. In this study, filamentous fungi from Sonsón-Antioquia region were isolated and characterized. A morphological characterization was carried out using taxonomic keys and additionally a biochemical characterization qualitatively evaluated the amylolytic, cellulolytic, lipolytic, proteolytic, catalase, peroxidase, and laccase capacity of the strains. Furthermore, isolated fungi were molecularly identified using the LSU region of the rDNA (28S). Among the strains identified, Trichoderma sp., Penicillium sp., Mucor sp. Aspergillus sp. and Lecythophora sp. genera were found and it was observed that the analyzed fungi present at least one of the seven enzymatic activities evaluated and some genera such as Trichoderma sp. and Aspergillus sp. present even six of them. Therefore, the isolated strains show desirable characteristics in food, paper, cosmetic, and textile industries, and in areas such as bioremediation and biological control.

Many examples of extreme virus resistance and posttranscriptional gene silencing of endogenous or reporter genes have been described in transgenic plants containing sense or antisense transgenes. In these cases of either cosuppression or antisense suppression, there appears to be induction of a surveillance system within the plant that specifically degrades both the transgene and target RNAs. We show that transforming plants with virus or reporter gene constructs that produce RNAs capable of duplex formation confer virus immunity or gene silencing on the plants. This was accomplished by using transcripts from one sense gene and one antisense gene colocated in the plant genome, a single transcript that has self-complementarity, or sense and antisense transcripts from genes brought together by crossing. A model is presented that is consistent with our data and those of other workers, describing the processes of induction and execution of posttranscriptional gene silencing.

Gene silencing is an important but little understood regulatory mechanism in plants. Here we report that a viral sequence, initially identified as a mediator of synergistic viral disease, acts to suppress the establishment of both transgene-induced and virus-induced posttranscriptional gene silencing. The viral suppressor of silencing comprises the 5′-proximal region of the tobacco etch potyviral genomic RNA encoding P1, helper component-proteinase (HC-Pro) and a small part of P3, and is termed the P1/HC-Pro sequence. A reversal of silencing assay was used to assess the effect of the P1/HC-Pro sequence on transgenic tobacco plants (line T4) that are posttranscriptionally silenced for the uidA reporter gene. Silencing was lifted in offspring of T4 crosses with four independent transgenic lines expressing P1/HC-Pro, but not in offspring of control crosses. Viral vectors were used to assess the effect of P1/HC-Pro expression on virus-induced gene silencing (VIGS). The ability of a potato virus X vector expressing green fluorescent protein to induce silencing of a green fluorescent protein transgene was eliminated or greatly reduced when P1/HC-Pro was expressed from the same vector or from coinfecting potato virus X vectors. Expression of the HC-Pro coding sequence alone was sufficient to suppress virus-induced gene silencing, and the HC-Pro protein product was required for the suppression. This discovery points to the role of gene silencing as a natural antiviral defense system in plants and offers different approaches to elucidate the molecular basis of gene silencing.

The changes in protein degradation behavior in fish surimi upon addition of different protease inhibitors were examined, with the aim of identifying the proteases involved in the modori reaction in different species and grades of fish and at different temperatures. The modori reactions at 40, 50, and 60°C in four frozen surimi samples: grades FA and KA blue grenadier and grades SA and RA Alaska pollock were investigated. In the grade FA blue grenadier surimi, the modori reaction primarily involved metalloproteases at 40°C, serine proteases and cysteine proteases at 50°C, and cysteine proteases at 60°C. The reaction in the grade KA blue grenadier surimi involved multiple proteases at 40°C, and metalloproteases and cysteine proteases at 50 and 60°C. In the Alaska pollock surimi, multiple proteases were suggested to be equally involved in the modori reaction at 40, 50, and 60°C in both grades SA and RA samples.

Plants respond to physical injury, such as that caused by foraging insects, by synthesizing proteins that function in general defense and tissue repair. In tomato plants, one class of wound-responsive genes encodes proteinase inhibitor (pin) proteins shown to block insect feeding. Application of many different factors will induce or inhibit pin gene expression. Ethylene is required in the transduction pathway leading from injury, and ethylene and jasmonates act together to regulate pin gene expression during the wound response

The het-s locus of Podospora anserina is a heterokaryon incompatibility locus. The coexpression of the antagonistic het-s and het-S alleles triggers a lethal reaction that prevents the formation of viable heterokaryons. Strains that contain the het-s allele can display two different phenotypes, [Het-s] or [Het-s*], according to their reactivity in incompatibility. The detection in these phenotypically distinct strains of a protein expressed from the het-s gene indicates that the difference in reactivity depends on a posttranslational difference between two forms of the polypeptide encoded by the het-s gene. This posttranslational modification does not affect the electrophoretic mobility of the protein in SDS/PAGE. Several results suggest a similarity of behavior between the protein encoded by the het-s gene and prions. The [Het-s] character can propagate in [Het-s*] strains as an infectious agent, producing a [Het-s*] to [Het-s] transition, independently of protein synthesis. Expression of the [Het-s] character requires a functional het-s gene. The protein present in [Het-s] strains is more resistant to proteinase K than that present in [Het-s*] mycelium. Furthermore, overexpression of the het-s gene increases the frequency of the transition from [Het-s*] to [Het-s]. We propose that this transition is the consequence of a self-propagating conformational modification of the protein mediated by the formation of complexes between the two different forms of the polypeptide

Functional properties and antioxidant activities of protein hydrolysates from tuna (Thunnus thynnus) heads (THPHs), with different degrees of hydrolysis, obtained by treatment with Bacillus mojavensis A21 alkaline proteases and Alcalase, were investigated. Protein content of all freeze-dried THPHs ranged from 73.74 ± 0.5 to 78.56 ± 1.2%. The THPHs had excellent solubility, compared to untreated tuna head proteins and possessed interfacial properties, which were governed by their concentrations. Similarly, at a degree of hydrolysis (DH) of 12 and 15%, greater than 90% nitrogen solubility was observed at all experimental pH values tested. The emulsifying activity index (EAI) and emulsion stability index (ESI) of both hydrolysates at different DHs decreased (p less than 0.05) with increasing DH. At low DH (5%), hydrolysates exhibited strong emulsifying properties. All THPHs produced by the A21 proteases generally showed higher antioxidative activity than that of the Alcalase protein hydrolysates. The highest DPPH radical-scavenging activity (78 ± 2.1% at 3 mg/mL) was obtained with a DH of 15%. The IC∧50 value for the β-carotene bleaching assay was 0.5 ± 0.03 mg/mL. Alcalase (DH = 12%) and A21 (DH = 15%) protein hydrolysates contained glutamic acid/glutamine and arginine as the major amino acids, followed by lysine, aspartic acid/ asparagine, histidine, valine, phenylalanine, and leucine. In addition, the THPHs had a high percentage of essential amino acids, which made up 50.52 and 50.47%, of the protein hydrolysates obtained by the Alcalase and A21 proteases, respectively. Therefore, THPHs can be used as a promising source of functional peptides with antioxidant properties.

Partial characterizations of digestive proteases were studied in three life stages of spotted rose snapper: early (EJ), middle (MJ) and late juvenile (LJ) with corresponding average weights of 21.3 ± 2.6 g (3 months after hatching, MAH), 190 ± 4.4 g (7 MAH), and 400 ± 11.5 g (12 MAH). At sampling points, the digestive tract was dissected into the stomach (St), pyloric caeca (PC), and the intestine in three sections (proximal (PI), middle (MI) and distal intestine (DI)). The effect of pH and temperature and specific inhibitors were evaluated for acid and alkaline proteases. Total acid and alkaline protease activity showed a tendency to increase with juvenile life stage of fish while trypsin activity decreased. Differences were found in acid and alkaline protease activities at different pH and temperatures during juvenile stages. Pepstatin A inhibited total activity in the stomach extract in all juvenile stages. Activity in total alkaline protease inhibition was significantly higher in EJ using TLCK, PMSF, SBTI, Phen and Ovo than in MJ and LJ, while no significant differences were found with TPCK inhibition. Therefore increases in protease activities with fish growth through juvenile stages in which a substitution or diversification in the type of alkaline enzymes exist. These results lead a better comprehension of changes in digestive potential of Lutjanidae fish.

Many foods are prepared using egg white, most of them being based on the foaming properties of egg white which are due to albumen proteins ability to encapsulate and retain air. Therefore, many scientists aim to find new methods to improve the volume and the stability of egg white foam. This paper is a review of various factors affecting the foaming ability of egg white.

The potential contribution of mechanical disruption by ultrasonics and endogenous proteolytic enzymes on the tenderisation of hen muscle were investigated. The importance of endogenous enzymes was evaluated using various specific inhibitors. Freshly obtained breast muscles of culled hens (6 groups) were treated with different proteolytic enzyme inhibitors and/or ultrasonics, each group was treated with different methods, and then stored at 4 deg C for 0, 1, 3, and 7 days. Shear force decreased by 1.19 kg, and shear force and cooking loss were reduced by 0.69 kg and 4.27%, respectively, in the incorporated group treatment. The calpastatin activity was affected by almost all treatments. Our results suggest that ultrasonics and endogenous proteases contributed to muscle degradation, thereby improving hen meat tenderness and decreasing the cooking loss. Muscle degradation, tenderness, and water-retaining properties of hens were improved by a combination of ultrasound and exogenous proteolytic enzyme inhibitors.