Marco Antonio López-Torres

Effluents of Shrimp Farms and Its Influence on the Coastal Ecosystems of Bahía de Kino, Mexico

The impact on coastal ecosystems of suspended solids, organic matter, and bacteria in shrimp farm effluents is presented. Sites around Bahía de Kino were selected for comparative evaluation. Effluent entering Bahia Kino (1) enters Laguna La Cruz (2). A control site (3) was outside the influence of effluents. Water quality samples were collected every two weeks during the shrimp culture period. Our data show that the material load in shrimp farm effluents changes biogeochemical processes and aquatic health of the coastal ecosystem. Specifically, the suspended solids, particulate organic matter, chlorophyll a, viable heterotrophic bacteria, and Vibrio-like bacteria in the bay and lagoon were two- to three-fold higher than the control site. This can be mitigated by improvements in the management of aquaculture systems.

Evaluation of the productive and physiological responses of Litopenaeus vannamei infected with WSSV and fed diets enriched with Dunaliella sp.

An experimental investigation was performed to evaluate the productive and physiological responses of Litopenaeus vannamei that were infected with WSSV and fed diets enriched with Dunaliella sp., which had a high β-carotene content induced by nitrogen reduction in the culture medium. A basal diet containing 35% crude protein and experimental diets T1 and T2, which included 1% and 2% microalgae meal, respectively, were evaluated. Positive (infected juveniles) and negative (non-infected) controls were also evaluated. Survival was significantly higher (80%) in the two treatment groups compared to the positive control group (56%). In the negative control group, survival was 100%. Some variation was recorded for hemolymph metabolites among treatments and at distinct times post-infection; although the tendencies were not clear, some metabolites (glucose and triglycerides) appeared to decrease on the last days of the trial, probably due to their use as energy for the shrimp to thrive despite the infection. The results of the study suggest a positive effect of the dietary inclusion of Dunaliella meal on shrimp survival and an unclear effect on hemolymph metabolites.

The Pacific oyster (Crassostrea gigas) Hsp70 modulates the Ostreid herpes virus 1 infectivity

Abstract The Ostreid herpes virus type 1 (OsHV‐1) is one of the most devastating pathogen in oyster cultures. Among several factors, as food limitation, oxygen depletion, salinity and temperature variations, episodes of “summer mortality” of the Pacific oyster Crassostrea gigas have also been associated with OsHV‐1 infection. Mortalities of C. gigas spat and juveniles have increased significantly in Europe, and contemporary mortality records of this mollusk in México have been associated with the occurrence of OsHV‐1. In the present study, the expression of the heat shock protein 70 gene from the Pacific oyster correlates with the abundance of DNA polymerase transcripts from the OsHV‐1. This may suggest that the induction on the expression of the Pacific oyster hsp70 may potentially participate in the immune response against the virus. Furthermore, this study reports for the first time a TEM representative image of the OsHV‐1 in aqueous solution, which possesses an icosahedral shape with a diameter of 70 nm × 100 nm. Finally, the examined sequence encoding the ORF4 of the OsHV‐1 isolate from northwest Mexico showed specific sequence variations when compared with OsHV‐1 isolates from distant geographical areas. Graphical abstract Figure. No Caption available. HighlightsWe studied the effect of OsHV‐1 on the expression of C. gigas hsp70.Hsp70 never returned to it amount of mRNA control organism level.Hsp70 levels were related to the infection level.In situ detection of host and pathogen genes in same tissues.First negative aqueous TEM images of the OsHV‐1.

Proteínas transmembranales de organismos tipo rickettsia (OTR) en animales acuáticos: Factores de adherencia, invasión e infección

Besides participating in the transport of essential compounds and as recipients of phages, transmembrane proteins of rickettsia-like organisms (RLO), play an important role in the infection process of commercially important organisms such as fish, mollusk and crustaceans. Recently a new classification of RLO which divides them into four groups was reported: ancestral, typhus, the spotted fever and transitional. To date, only the typhus (TG) and spotted fever (SFG) groups have been reported as pathogenic of marine organisms. The outer membrane surface of the TG group has antigens type 0, 1, 2, 4, 5 (Sca0, Sca1, Sca2, Sca4, Sca5). Sca0 are also known as outer membrane proteins A (OmpA) and Sca5 as outer membrane proteins B (OmpB). Other outer membrane proteins such as enzymes called translocase (Tlc) have been detected, including translocase 1, 4 and 5 (Tlc1, Tlc4 and Tlc5). All these proteins (except for Sca0) have been detected in the SFG group. These proteins vary in features and functions. However, the information of RLO affecting marine organisms is not as common as that of terrestrial mammals. An analysis of the state of the art on the study of transmembrane proteins of RLO in marine organisms is performed in this review; additionally, the hypothetical infection mechanism of these RLO is inferred by using this information together with that reported of RLO affecting terrestrial organisms.