Antigen Presentation and Autophagy in Teleost Adaptive Immunity

Infectious diseases are a burden for aquaculture. Antigen processing and presentation (APP) to the immune effector cells that fight pathogens is key in the adaptive immune response. At the core of the adaptive immunity that appeared in lower vertebrates during evolution are the variable genes encoding the major histocompatibility complex (MHC). MHC class I molecules mainly present peptides processed in the cytosol by the proteasome and transported to the cell surface of all cells through secretory compartments. Professional antigen-presenting cells (pAPC) also express MHC class II molecules, which normally present peptides processed from exogenous antigens through lysosomal pathways. Autophagy is an intracellular self-degradation process that is conserved in all eukaryotes and is induced by starvation to contribute to cellular homeostasis. Self-digestion during autophagy mainly occurs by the fusion of autophagosomes, which engulf portions of cytosol and fuse with lysosomes (macroautophagy) or assisted by chaperones (chaperone-mediated autophagy, CMA) that deliver proteins to lysosomes. Thus, during self-degradation, antigens can be processed to be presented by the MHC to immune effector cells, thus, linking autophagy to APP. This review is focused on the essential components of the APP that are conserved in teleost fish and the increasing evidence related to the modulation of APP and autophagy during pathogen infection.Versión del editor2,46

Placing the COVID-19 Pandemic in a Marine Ecological Context: Potential Risks for Conservation of Marine Air-Breathing Animals and Future Zoonotic Outbreaks

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Inmunodominancia y procesamiento de epítopos de la glicoproteína F del virus respiratorio sincitial humano reconocidos por linfocitos T citotóxicos CD8+ murinos

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 16-06-2006Human respiratory syncytial virus (RSV) is a major cause of respiratory infection in children and in the elderly. The RSV fusion (F) glycoprotein has long been recognized as a vaccine candidate as it elicits cytotoxic T lymphocyte (CTL) and antibody responses. Two murine H-2Kd-restricted CTL epitopes (F85-93 and F92-106) are known in the F protein of the A2 strain of RSV. We generated F-specific CTL lines using BCH4 fibroblasts that are persistently infected with the Long strain of human RSV as stimulators and found that in this strain only the F85-93 epitope is conserved. Motif based epitope prediction programmes and an F2 chain deleted F protein encoded in a recombinant vaccinia virus (rVV) enabled us to identify a new epitope in the Long strain, F249-258, which is presented by Kd as a 9mer (TYMLTNSEL) or a 10mer (TYMLTNSELL) peptide. F249-258-specific CTL are induced in vivo during the immune response to RSV or to vvF, a rVV encoding the entire F protein. The immunodominance pattern between epitopes F85-93 and F249-258 was assessed by quantifying CD8+ T-lymphocyte responses to epitopes F85-93 and F249-258. Our results show CD8+ T-lymphocyte responses are strongly skewed to F85-93 in in vitro multispecific CTL lines and in vivo during a secondary response to vvF. However, no hierarchy in CD8+ T-lymphocyte responses to F85-93 and F249-258 epitopes was observed in vivo during a primary response. Processing and presentation of epitopes F85-93 and F249-258 was studied and major differences in presentation pathways were found depending on the epitope and on the viral context of the antigen. Epitope F85-93 is presented through an endogenous pathway dependent on the transporters associated with antigen processing (TAP) when the F protein is in either RSV or rVV context. The proteasome mediates this pathway in cells infected with rVV encoding either native F protein, a cytosolic form, or a form that is retained before the mid-Golgi. Moreover, in rVV-infected cells, an additional endogenous TAP-independent presentation pathway is also functioning for this epitope. In contrast, epitope F249-258 is mainly presented through two TAP-independent pathways when the F protein is expressed from RSV or rVV, that differ in that presentation is endogenous or mostly exogenous, respectively. Our results contribute to the study in murine models of the role of CTL in the immune response to RSV F protein, and underscore the diversity of MHC class I processing pathways available for presentation of epitopes to CTL

Reservoirs of Red-Spotted Grouper Nervous Necrosis Virus (RGNNV) in Squid and Shrimp Species of Northern Alboran Sea

The production of the aquaculture industry has increased to be equal to that of the world fisheries in recent years. However, aquaculture production faces threats such as infectious diseases. Betanodaviruses induce a neurological disease that affects fish species worldwide and is caused by nervous necrosis virus (NNV). NNV has a nude capsid protecting a bipartite RNA genome that consists of molecules RNA1 and RNA2. Four NNV strains distributed worldwide are discriminated according to sequence homology of the capsid protein encoded by RNA2. Since its first description over 30 years ago, the virus has expanded and reassortant strains have appeared. Preventive treatments prioritize the RGNNV (red-spotted grouper nervous necrosis virus) strain that has the highest optimum temperature for replication and the broadest range of susceptible species. There is strong concern about the spreading of NNV in the mariculture industry through contaminated diet. To surveil natural reservoirs of NNV in the western Mediterranean Sea, we collected invertebrate species in 2015 in the Alboran Sea. We report the detection of the RGNNV strain in two species of cephalopod mollusks (Alloteuthis media and Abralia veranyi), and in one decapod crustacean (Plesionika heterocarpus). According to RNA2 sequences obtained from invertebrate species and reported to date in the Mediterranean Sea, the strain RGNNV is predominant in this semienclosed sea. Neither an ecosystem- nor host-driven distribution of RGNNV were observed in the Mediterranean basin.Versión del edito

Physiological and training characteristics of recreational marathon runners

Purpose: The aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5–3 h, 3–3.5 h, 3.5–4 h, 4–4.5 h and >4.5 h). Materials and methods: A total of 97 recreational marathon runners (age 42.4 ± 9.9 years; mass 69.2 ± 11.3 kg; stature 172.8 ± 9.1 cm), with a marathon finish time of 229.1 ± 48.7 min, of whom n = 34 were female and n = 63 were male, completed an incremental treadmill test for the determination of lactate threshold (LT1), lactate turn point (LT2) and running economy (RE). Following a 7-min recovery, they completed a test to volitional exhaustion starting at LT2 for the assessment of VO2max. In addition, all participants completed a questionnaire gathering information on their current training regimes exploring weekly distances, training frequencies, types of sessions, longest run in a week, with estimations of training speed, and load and volume derived from these data. Results: Training frequency was shown to be significantly greater for the 2.5–3 h group compared to the 3.5–4 h runners (P 4.5 h group (P = 0.004), while distance per session (km⋅session–1) was significantly greater for the 2.5–3 h group (16.1 ± 4.2) compared to the 3.5–4 h group (15.5 ± 5.2; P = 0.01) and >4.5 h group (10.3 ± 2.6; P = 0.001). Race speed correlated with LT1 (r = 0.791), LT2 (r = 0.721) and distance per session (r = 0.563). Conclusion: The data highlight profound differences for key components of marathon running (VO2max, LT1, LT2, RE and % VO2max) within a group of recreational runners with the discriminating training variables being training frequency and the absolute training speed

Slingshot prominence evolution for a solar-like star

Funding: UK STFC grant (ST/M001296/1) (CVD, MJ).Although the present-day Sun rotates too slowly to exhibit centrifugally supported ‘slingshot prominences’, at some time during its past it may have formed these clouds of cool gas and ejected them into the interplanetary medium. We determine the time period for this behaviour using a rotation evolution code to derive the properties of the formation and ejection of slingshot prominences during the lifetime of a star similar to our Sun. The mass, mass-loss rate, and rate of ejection of these prominences are calculated using the analytical expression derived in our previous work. We find that for stars with an initial rotation rate larger than 4.6Ω⊙⁠, about half of all solar mass stars, slingshot prominences will be present even after the star reaches the main-sequence phase. In a fast rotator, this means that prominences can form until the star reaches ∼800 Myr old. Our results also indicate that the mass and lifetime of this type of prominence have maximum values when the star reaches the zero-age main sequence at an age of ∼40 Myr for a solar mass star.Publisher PDFPeer reviewe

Detection of Red-spotted grouper nervous necrosis virus (RGNNV) in shrimp and squid of the Mediterranean Sea

The quest for sustainable fisheries and procurement of food supply has increased aquaculture production up to the world fisheries capture. Viral encephalopathy and retinopathy (VER), also known as viral nervous necrosis (VNN), is caused by nervous necrosis virus (NNV) and results in high mortality of larvae and juveniles of continuous increasing amount of fish species. The disease causes vacuolation and necrosis of the central nervous system. The virus has a nude capsid protecting a bipartite RNA genome that consists of positive stranded molecules RNA1 and RNA2. Four NNV genotype strains distributed worldwide are discriminated according to sequence homology of the capsid protein encoded by RNA2. Preventive treatments prioritize the RGNNV (Redspotted grouper nervous necrosis virus) genotype that has the highest optimum temperature for replication and the broadest range of susceptible species. A flow of NNV between wild and cultured fish had been demonstrated, and reservoirs of NNV have been reported in invertebrates, raising concern on the spreading of NNV in the mariculture industry through contaminated food. The present study aimed to contribute in the surveillance of reservoirs of NNV in invertebrates of the unexplored western Mediterranean Sea. We report the detection of the RGNNV strain in two species of squid (Alloteuthis media and Abralia veranyi), and in one shrimp (Plesionika heterocarpus) collected in 2015 in the Alboran Sea. According to RNA2 sequences obtained from invertebrates and reported to date in the Mediterranean Sea, the strain RGNNV is predominant in this semi-enclosed sea. Our results suggest that RGNNV distribution is apparently independent of host species and ecosystem, and similar between invertebrates and fish species that feed on invertebrates, calling for an increase in surveillance of NNV reservoirs in the wild.European Association of Fish Pathologists. PathoVe

Detection of Red-spotted grouper nervous necrosis virus (RGNNV) in shrimp and squid of the Mediterranean Sea

The quest for sustainable fisheries and procurement of food supply has increased aquaculture production up to the world fisheries capture. Viral encephalopathy and retinopathy (VER), also known as viral nervous necrosis (VNN), is caused by nervous necrosis virus (NNV) and results in high mortality of larvae and juveniles of continuous increasing amount of fish species. The disease causes vacuolation and necrosis of the central nervous system. The virus has a nude capsid protecting a bipartite RNA genome that consists of positive stranded molecules RNA1 and RNA2. Four NNV genotype strains distributed worldwide are discriminated according to sequence homology of the capsid protein encoded by RNA2. Preventive treatments prioritize the RGNNV (Redspotted grouper nervous necrosis virus) genotype that has the highest optimum temperature for replication and the broadest range of susceptible species. A flow of NNV between wild and cultured fish had been demonstrated, and reservoirs of NNV have been reported in invertebrates, raising concern on the spreading of NNV in the mariculture industry through contaminated food. The present study aimed to contribute in the surveillance of reservoirs of NNV in invertebrates of the unexplored western Mediterranean Sea. We report the detection of the RGNNV strain in two species of squid (Alloteuthis media and Abralia veranyi), and in one shrimp (Plesionika heterocarpus) collected in 2015 in the Alboran Sea. According to RNA2 sequences obtained from invertebrates and reported to date in the Mediterranean Sea, the strain RGNNV is predominant in this semi-enclosed sea. Our results suggest that RGNNV distribution is apparently independent of host species and ecosystem, and similar between invertebrates and fish species that feed on invertebrates, calling for an increase in surveillance of NNV reservoirs in the wild.European Association of Fish Pathologists. PathoVe

Genetic connectivity between Atlantic bluefin tuna (ABFT) Larvae Spawned in the GOM and MED

Highly migratory Atlantic bluefin tuna (ABFT) is managed as two stocks, Western and Eastern. Western ABFT spawn mainly in the Gulf of Mexico (GOM) and Eastern ABFT in the Mediterranean Sea (MED) (1). Understanding connectivity between ABFT populations is important for conservation and management of this valuable fishery resource that has been exploited for centuries. ABFT are highly mixed, with multiple disciplines supporting weak structuring between Western and Eastern stocks (1). Concerning genetics, subtle structuring of ABFT populations across the Atlantic Ocean has been the conclusion of studies describing genetic tools for traceability (2,3). Larval fish provide the genetic signal of successful breeders and have occasionally been genetically characterized with juveniles (young-of-the-year, YOY) collected in nursery areas. For the first time, cooperative field collection of tuna larvae during 2014 in the main spawning area for each stock enabled us to assess the structuring of ABFT genetic diversity in a precise temporal and spatial frame exclusively through larvae (5). Partitioning of genetic diversity at nuclear microsatellite loci and in the mitochondrial control region resulted in low significant fixation indices. Individual-based clustering analysis of larval ABFT genetic diversity indicate apparent connectivity between the GOM and MED spawning grounds that could support the hypothesis of mixing of breeders belonging to different stocks.This collaborative study was supported by "ECOLATUN" PROJECT CTM2015-68473-R (MINECO/FEDER) funded by Spanish Ministry of Economy and Competitiveness; "TUNAGEN" project funded by IEO; and "BLUEFIN" project financed by IEO and Balearic Island Observing and Forecasting System (SOCIB). This research was funded by NASA (NNX11AP76G S07), the NOAA National Marine Fisheries Science Service through the Southeast Fisheries Science Center, as well as by Cooperative Institute for Marine and Atmospheric Studies under Cooperative Agreement NA15OAR43200064 at the University of Miami. There was no additional external funding received for this study. The scientific results and conclusions, as well as any views or opinions expressed herein, are those of the author(s) and do not necessarily reflect those of NOAA or the Department of Commerce

Characterization of the plankton community composition in Málaga Bay (NW Alboran Sea) by means of integrative taxonomy.

The Alboran Sea is highly dynamic from a hydrographical point of view. Depending on the strength of the currents and the direction of the wind the surface coastal water masses can be either of Atlantic or Mediterranean origin. This variability affects both the phytoplankton and zooplankton components of the community inhabiting the Bay of Málaga. In addition, fish larvae distribution varies with the diel cycle, affecting zooplankton distribution in shallow waters. In order to provide a first insight into the variability of the planktonic community composition in the area during a 24 hour cycle, we applied an integrative approach combining morphological and molecular tools