Response to short term ultraviolet stress in the reef-building coral "Pocillopora capitata" (Anthozoa: Scleractinia)

[EN]Coral reefs are impacted by a range of environmental variables that affect their growth and survival, the main factors being the high irradiance and temperature fluctuations. Specimens of Pocillopora capitata verrill 1864 were exposed to photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) for 32h under laboratory conditions. We examined lipid peroxidation (MDA), antioxidant enzyme activities (SOD, CAT, GPx and GST), chlorophyll a (Chl a), carotenoid pigments (CPs), mycosporine-like amino acids (MAAs), and expulsion of zooxanthellae. Our results revealed that corals exposed to UVR had relatively low levels of carotenoids and antioxidant enzyme activities compared to those exposed to PAR, as well as lower CPs/Chl a ratios. Although MAAs and CPs are rapidly produced as non-enzymatic antioxidants in response to UVR in corals, these were not sufficient, even in the dark phase of the experiment, to mitigate the damage caused by formation of reactive oxygen species (ROS), which caused breakdown of the symbiotic relationship between the zooxanthellae and the host animal to an extent 33 times greater than in the PAR treatment. In this study, it could be possible to distinguish that, parallel to the short-term adjustments, such as the amount of pigment in the algae or the sensitivity of the photosynthetic response reported in other species of coral, P. capitata exhibits at the enzymatic level a series of responses oriented to resist the effects derived from the propagation of ROS and, thus, to adapt to and maintain its reproductive capacity in shallow oceanic environments that commonly exhibit high UVR levels. Nevertheless, as a result of the inappropriate location of the artificial intercommunication structure of the Juluapan Lagoon with respect to the arrecifal area of study and therefore of the tides influence, other variables, such as the changes in short-term in turbidity, sediment inputs, nutrients, temperature and osmolarity, can act in combination and cause irreversible damage. The implementation of a management plan for the coralline reefs of the Mexican Pacific coast is required.[ES]Los arrecifes de coral se ven afectados por una serie de variables ambientales que afectan su crecimiento y supervivencia, siendo los principales factores la alta irradiación y las fluctuaciones de temperatura. Los especímenes de Pocillopora capitata Verrill 1864 fueron expuestos a radiación activa fotosintéticamente (PAR) y radiación ultravioleta (RUV) por 32h en condiciones de laboratorio. Nosotros determinamos las concentraciones de peroxidación lipídica (MDA), actividades de enzimas antioxidantes (SOD, CAT, GPx y GST), clorofila a (Chl a), pigmentos carotenoides (CPS), aminoácidos tipo micosporina (MAAS), y la expulsión de las zooxantelas. Nuestros resultados muestran que los corales expuestos a los rayos UV presentaban niveles relativamente bajos de carotenoides y actividad de las enzimas antioxidantes en comparación con los expuestos al PAR, así como tasas de CPs/Chl a bajas. Aunque MAAs y CPs se producen rápidamente como antioxidantes no enzimáticos en respuesta a la radiación ultravioleta en los corales, éstos no fueron suficientes, incluso en la fase oscura del experimento, para mitigar los daños causados por la formación de especies reactivas de oxígeno (ROS), lo que provocó una ruptura en la relación simbiótica entre las zooxantelas y el coral con una relación 33 veces mayor que en el tratamiento de PAR. A nivel enzimático, P capitata presentó una serie de ajustes orientados a resistir los efectos derivados de la propagación de ROS y con ello favorecer su adaptación y capacidad reproductiva en ambientes oceánicos caracterizados por altos niveles de UVR.SIThis project was supported by the PROMEP of the Secretary of Public Education, Mexico

Polyculture and growth of the Nile tilapia Oreochromis niloticus (Perciformes:Cichlidae) with shrimp Litopenaeus vannamei (Decapoda:Penaeidae) in sea water

Globally, the tilapia is the second most important group of commercial fish. Polyculture and growth were studied for 181 Nile tilapia, Oreochromis niloticus, in a seawater pond (30-37‰) at a density of 50 fish/m3 for six months (October to April) with 30 shrimp Litopenaeus vannamei at a density of 8 shrimp/m3 in two months (December-February) in an open tank of 3,6 m3. They were fed Camaronina”pellets” at libitum in the morning. The pond bottom was siphoned every other day, was maintained with constant aeration. Water exchange was 80% every two weeks. The temperature varied from 18 to 32oC. The tilapia grew from 72mm to 220mm, and 7g to 232g, survival was 92%. The total biomass was 38,6 kg. The shrimp grew from 6,8 g to 11,5 g and 102mm to 121mm. The survival rate was 100%. Total biomass was 219g. The feed conversion ratio (FCR) was 1,3:1,0 in both species. There was no problem between species; this polyculture is recommended.KEY WORDSPolyculture, growth, Litopenaeus vannamei, Oreochromis niloticus, biomass, densitySe estudió el policultivo y el crecimiento de 181 tilapias del Nilo Oreochromis niloticus en un estanque con agua de mar (30-37‰) a una densidad de 50 peces/m3 en seis meses (octubre a abril) con 30 camarones Litopenaeus vannamei a una densidad de 8 camarones/m3 en dos meses (diciembre-febrero) en un tanque abierto de 3,6 m3. Fueron alimentados “pellets” Camaronina at libitum en la mañana. El fondo del estanque fue sifonado cada tercer día, se mantuvo con aireación constante. El intercambio de agua fue del 80% cada dos semanas. El rango de temperatura varió de 18 a 32oC. La tilapia creció de 72mm a 220mm, y de 7g a 232g, la supervivencia fue del 92%. La biomasa total fue de 38,6 kg. El camarón creció de 6,8g y 102mm a 11,5g y 121mm. La tasa de supervivencia fue del 100%. La biomasa total fue de 219g. La tasa de conversión alimenticia (FCR) fue 1,3:1,0 en ambas especies. No hubo ningún problema entre las especies; se recomienda un policultivo de ambas. PALABRAS CLAVEPolicultivo, crecimiento, Litopenaeus vannamei, Oreochromis nilotica, biomasa, densidad, supervivenci

Lysosomal dysfunction impairs mitochondrial quality control and is associated with neurodegeneration in <i>TBCK</i> encephaloneuronopathy

Abstract Biallelic variants in the TBCK gene cause intellectual disability with remarkable clinical variability, ranging from static encephalopathy to progressive neurodegeneration (TBCK-Encephaloneuronopathy). The biological factors underlying variable disease penetrance remain unknown. Since previous studies had suggested aberrant autophagy, we tested whether mitophagy and mitochondrial function are altered in TBCK−/− fibroblasts derived from patients exhibiting variable clinical severity. Our data show significant accumulation of mitophagosomes, reduced mitochondrial respiratory capacity and mitochondrial DNA content, suggesting impaired mitochondrial quality control. Furthermore, the degree of mitochondrial dysfunction correlates with a neurodegenerative clinical course. Since mitophagy ultimately depends on lysosomal degradation, we also examined lysosomal function. Our data show that lysosomal proteolytic function is significantly reduced in TBCK−/− fibroblasts. Moreover, acidifying lysosomal nanoparticles rescue the mitochondrial respiratory defects in fibroblasts, suggesting impaired mitochondrial quality control secondary to lysosomal dysfunction. Our data provide insight into the disease mechanisms of TBCK Encephaloneuronopathy and the potential relevance of mitochondrial function as a biomarker beyond primary mitochondrial disorders. It also supports the benefit of lysosomal acidification strategies for disorders of impaired lysosomal degradation affecting mitochondrial quality control.</jats:p

Lysosomal dysfunction impairs mitochondrial quality control and predicts neurodegeneration in TBCKE

AbstractBiallelic variants in TBC1-domain containing kinase (TBCK) cause intellectual disability in children. It remains unclear how variants in TBCK lead to a neurodevelopmental disorder and what biological factors modulate the variability of clinical severity. Previous studies showed increased autophagosomes in patients sharing the truncating (p.R126X) Boricua homozygous TBCK variant, who exhibit a severe and progressive neurodegenerative phenotype. Since defects in mitophagy are linked to neurodegenerative disorders, we tested whether mitophagy and mitochondrial function are altered in TBCK-/- fibroblasts. Our data shows significant accumulation of mitophagosomes, reduced mitochondrial respiratory capacity, and mtDNA depletion. Furthermore, mitochondrial dysfunction correlates with the severity of the neurological phenotype. Since effective mitophagy and degradation of mitophagosomes ultimately depends on successful lysosomal degradation, we also tested lysosomal function. Our data shows that lysosomal proteolytic function is significantly reduced in TBCK-/- fibroblasts. Moreover, acidifying lysosomal nanoparticles rescue the mitochondrial respiratory defects, suggesting that impaired mitochondrial quality control secondary to lysosomal dysfunction, may play an important role in the pathogenicity of this rare neurodevelopmental disorder and predict the degree of disease progression and neurodegeneration.</jats:p