FOSFATASA ALCALINA DE CAMARÓN: ESTRUCTURA, CARACTERÍSTICAS Y FUNCIONES/ SHRIMP ALKALINE PHOSPHATASE: STRUCTURE, CHARACTERISTICS, AND FUNCTIONS

Los estudios sobre la fosfatasa alcalina (FA) son escasos en especies de origen terrestre; existe poca información de esta enzima con respecto a las especies marinas, como el camarón. Los principales aspectos considerados en esta revisión son: la estructura, características y funciones de la fosfatasa alcalina presente en camarones (FAC), comparadas con sus homólogos de diferentes orígenes. Las tríadas del sitio activo de la FAC son muy similares a los de FA de origen bacteriano. Diversos agentes que actúan como inhibidores de la FA comercial, también pueden inhibir a la FAC. Las principales funciones de la FA en crustáceos, como el camarón, se relacionan con el proceso digestivo del organismo, participando en reacciones de transfosforilación, así como en el sistema inmunológico, en la que se ha asociado a la activación de los efectores celulares responsables del sistema de defensa del camarón, por lo que puede ser utilizado cómo un agente indicador de enfermedades en estos organismos. Por otro lado, debido a que las características químicas y estructurales de la FAC son similares a las de sus homólogos de origen bacteriano, se infiere que los usos y aplicaciones de la FAC pueden ser semejantes a las de origen bacteriano. ABSTRACT Studies on alkaline phosphatase (AP) are few on terrestrial species; there is little information of this enzyme with respect to marine species, especially shrimp. The main aspects considered in this review are structure, characteristics and functions present in shrimp alkaline phosphatase (SAP) compared with their equivalents from different sources. The triads of the SAP active site are very similar to those of AP of bacterial origin, these last being widely studied and used as a model. Several agents that act as inhibitors of the commercial AP, also can inhibit the SAP. Of the main functions of the AP in crustaceans, such as shrimp, are those related to the digestive process of the organism, participating in transphosphorylation reactions and the immune system, which has been associated with activation of cellular effectors responsible of shrimp defense system, so it can be used as an indicator of disease agent in this organism. Moreover, because the chemical and structural characteristics of the SAP are similar to those of their bacterial homologues, uses and applications of SAP can be similar to those of bacterial origin

Efecto Inhibitorio de Extractos Hidroalcoholicos de Larrea Tridentata Sobre Saprolegnia Sp

In recent years, the aquaculture sector has undergone rapid growth owing to its significance in food production. Nonetheless, freshwater fish industries are encountering significant hurdles, including diseases caused by Oomycetes, like Saprolegniae. This research project evaluates the impact of Larrea tridentata extract on inhibiting Saprolegnia Sp. through an in vitro bioassay. Saprolegnia strains were procured from fish afflicted with this Oomycete. Morphological methods were employed to identify the fungus, resulting in the isolation of two strains - S. parasitica and S. Ferax - which were tested in the inhibitory assay. The yield was found to be 167.5 mg/mL in methanol and 113 mg/mL in ethanol. Phytochemical analysis revealed the presence of phenols, flavonoids and tannins, as well as intense antioxidant activity. Concentrations above 50 mg/mL exhibited complete inhibition of the Oomycete. This suggests that the utilization of an ethanolic extract presents a promising option for implementation in aquatic organisms.En los últimos años, el sector acuícola ha experimentado un rápido crecimiento debido a su relevancia en la producción alimentaria. No obstante, las industrias de peces de agua dulce se enfrentan a grandes desafíos, incluyendo enfermedades causadas por Oomicetos, como Saprolegniae. En este proyecto se evaluó el efecto del extracto de Larrea tridentata sobre la inhibición de Saprolegnia Sp. mediante un bioensayo in vitro. Las cepas de Saprolegnia fueron obtenidas  de peces infectados con este Oomiceto. La identificación del hongo se realizo vía morfológica obteniéndose dos cepas S. parasítica y S. Ferax. Las cuales fueron usadas en el ensayo inhibitorio. El rendimiento fue de 167.5 mg/mL en metanol y 113 mg/mL en etanol, el análisis fitoquímico reveló la presencia de fenoles, flavonoides y taninos, así como una intensa actividad antioxidante. En cuanto a la inhibición del Oomiceto, se encontró que a una concentración arriba de 50 mg/mL presentaba una inhibición completa del microorganismo. Lo anterior permite concluir que el uso de extracto etanólico es una opción potencial para su uso en organismos acuáticos

Effect of commercial probiotics addition in a biofloc shrimp farm during the nursery phase in zero water exchange

In biofloc technology systems (BFT) the bacterial community plays the most important role at recycling the organic matter and metabolizing the toxic nitrogenous compounds. The aim of this study was to evaluate the effect of two groups of commercial probiotics on the abundance of viable heterotrophic bacteria (VHB), ammonia oxidizing bacteria (AOB) and Vibrio-like (VLB), nitrogenous compounds and productive parameters of whiteleg shrimp Litopenaeus vannamei in a commercial farm. The study was developed during nursery phase in zero water exchange. Two groups of probiotics (PB1 and PB2) and one control (PBN; no probiotic) were evaluated in three replics. Shrimp postlarvae (7.3 mg) were stocked in ponds (70 m3) at densities of 500 in./m2. Commercial probiotics (Efinol PT-Lab. Robles and Epicin ponds-Epicin hatcheries) were incubated for 36 h in bioreactors (1 m3) and supplied every 3 d in PB1 and PB2 treatments. Basic variables of water quality, nitrogenous compounds and bacterial groups were monitored. At the beginning of the experiment, the abundance of VHB was lower in the PBN treatment, but as the bioassay progressed, the densities were similar to PB1 and PB2. In general VLB showed similar tendency to VHB, but significant difference were determined among treatments. The AOB abundance was similar in all treatments. Nitrogenous compounds and productive parameters of shrimp did not show significant differences between treatments. In the PBN ponds the zero water exchange could have promoted benefical bacteria of the natural biota. The addition of probiotics did not improve the water quality nor productive response of L. vannamei. Keywords: Ammonia oxidizing bacteria, Biofloc, Heterotrophic bacteria, Shrimp nursery, Probiotics, Vibrio-like bacteri

Cromatografía de interacción hidrofóbica como método de separación de proteasas alcalinas de vísceras de Scomberomorus sierra

This study focused on recovering alkaline proteases from the viscera of Scomberomorus sierra through hydrophobic interaction chromatography. Three alkaline proteases were partially separated using this chromatographic technique; two of them, with molecular weights of 19 and 31 kDa, were identified as trypsin-like enzymes according to inhibition assays. The 31 kDa alkaline protease, the only isolated enzyme, was purified under following chromatographic conditions: ammonium sulfate 13% (w/v) and ethylene glycol 27% (w/v); this enzyme showed maximum activity at pH 9 – 10 and 50 – 60 °C and was strongly inhibited by soybean trypsin inhibitor (SBTI) and porcine trypsin inhibitor (TPI). A third alkaline protease with molecular weight of 20 kDa was partially separated and inhibited by tosyl phenylalanyl chloromethyl ketone (TPCK), showing optimum activity at pH 9 – 11 and 60 °C. These results show that the viscera of Scomberomorus sierra may be useful as source of proteases.Este estudio se enfocó en recuperar proteasas alcalinas de vísceras de Scomberomorus sierra  mediante cromatografía de interacción hidrofóbica. Tres proteasas alcalinas se lograron separar parcialmente usando esta técnica cromatográfica; dos de ellas con pesos moleculares de 19 y 31 kDa fueron identificadas como enzimas tipo tripsina de acuerdo a ensayos de inhibición. La proteasa alcalina con peso molecular de 31 kDa, única enzima aislada, fue purificada bajo las siguientes condiciones cromatográficas: sulfato de amonio l3% (p/v) y etilenglicol al 27% (p/v); esta enzima mostró actividad máxima a pH 9 – 10 y 50 – 60 °C y fue fuertemente inhibida por el inhibidor de tripsina de soya (SBTI) como por el inhibidor de tripsina porcina (TPI). Una tercera proteasa alcalina con peso molecular de 20 kDa fue parcialmente separada e inhibida por tosil fenilalanil clorometil cetona (TPCK), la cual mostró actividad óptima a pH 9 – 11 y 60 °C. Estos resultados muestran que las vísceras de Scomberomorus sierra podrían ser de utilidad como fuente de proteasas

Intestinal Lipase Characterization in Common Snook (<em>Centropomus undecimalis</em>) Juveniles

The common snook (Centropomus undecimalis) is a euryhaline fish with high commercial demand in the Mexican southeast, Caribbean, and South America. However, some aspects of its digestive physiology are still unknown, particularly in relation to lipid hydrolysis. Therefore, the characterization of the digestive lipase of this species was carried out. Our results show that the digestive lipase’s optimal temperature is 35 °C, being stable between 25 and 35 °C, and shows maximum activity at pH 9, with stability between pH 5 and 8. Different degrees of inhibition were presented by Orlistat (61.4%), Ebelactone A (90.36%), Ebelactone B (75.9%), SDS 1% (80.7%), SDS 0.1% (73.5%), and SDS at 0.01% (34.9%). Orlistat and Ebelactone A and B completely inhibited the lipase band in the zymogram, but not SDS addition. Lipase showed a molecular weight of 43.8 kDa. The high lipase activities in the digestive tract indicate the importance of lipids in the diet of C. undecimalis

High-Intensity Ultrasound Pulses Effect on Physicochemical and Antioxidant Properties of Tilapia (Oreochromis niloticus) Skin Gelatin

Ultrasonic pulses are considered green technology for the improvement of the functional properties of proteins. In this study, four high-intensity ultrasound pulse treatments (ultrasound-pulsed gelatin (UPG)-42, UPG-52, UPG-71, UPG-84, and non-pulsed control gelatin (CG)) were applied to tilapia (Oreochromis niloticus) skin gelatin in order to study their effect on its physicochemical and antioxidant properties; a non-treated gelatin was used as a control. UPGs showed a significant increase in soluble protein and surface hydrophobicity compared to the control gelatin, and no significant difference was found in the electrophoretic profiles. The effects on the secondary structure were studied by circular dichroism and infrared spectra, and these showed that the random coil conformation was the main component in all treatments and the ultrasonic treatments only affected the &alpha;-helix and &beta;-sheet proportion. Finally, the ABTS ((2,2&prime;-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (ferric reducing ability) assays demonstrated that ultrasound treatments could improve the antioxidant activity of gelatins as free radical scavengers and electron donors. These results suggest that high-intensity ultrasound pulse technology is useful to improve fish gelatin antioxidant properties, which could be associated with secondary structure disruption

Effect of Ultrasonic Pulses on the Functional Properties of Stickwater

Large volumes of waste are generated in the processing operations of the fishing industry. These effluents contain potentially useful proteins. However, it is necessary to concentrate them for utilization. The stickwater (SW) resulting from this operation was subjected to a protein-fractionation step, pH adjustment (acid + alkaline) and ultrasonic pulsing in order to aid in hydrolysis and evaluate its functional and nutritional properties. The protein fractions, as well as the protein hydrolysates present in the tail water, had a chemical composition of 54.85 ± 4.21 and 74.81 ± 3.89 protein (%), 0.8 ± 0.1 and 0.2 ± 0.015 fat (%), 7.21 ± 0.67% ash (%), respectively. The increase in low-molecular-weight peptides results in an increase in free-radical scavenging activity. However, the increase in ferric-reducing antioxidant power may be due to the HCl treatment performed by the company. An increase in the functional properties of the samples treated with ultrasonic pulses was observed. Therefore, the chemical, nutritional and functional characteristics of stickwater suggest its potential use as a food additive