First isolation and characterization of clinical signs of polymicrobial infection by Aeromonas jandiae, Aeromonas hydhophila and Edwardsiella tarda in disease outbreak of fingerlings Arapaima gigas (pirarucu).

The topic of bacterial polymicrobial infection, still little studied in fish farming, has been demonstrating to be an important cause of economic losses in aquiculture. The Brazilian national production of Arapaima gigas, Schinz 1822 (pirarucu) in 2014 was around 12 tons. In Brazil, there is little information on the diversity of bacteria in aquatic ecosystems, mainly on the pirarucu microbiota, as well as on the bacteria that cause diseases in this fish of great importance for Brazilian and Amazonian aquaculture. However, identification and characterization of diseases caused by bacteria are of great importance for the sustainability of productive chain of fish farming. The aim of this study was to report the first polymicrobial outbreak in newly acquired pirarucus from commercial fish farming, which resulted in significant financial losses, which resulted mortality of approximately 1,400 farmed fingerlings. Fish with and without external signs of bacteriosis were collected for bacteriological analyzes. The isolated bacterial strains were characterized according to traditional taxonomical analyses and were identified as Aeromonas jandaei, Aeromonas hydrophila, and Edwardsiella tarda. In the pirarucus tegument with aeromonose and edwardsielose, lesions that varied in shape, extension and size were observed, and such lesions occurred mainly in the tail and fins of the fish. Anorexia, loss of balance with erratic movement, reduction of respiratory movements, depigmentation along the body with hemorrhagic foci, necrotic hemorrhages in internal organs such as kidney, liver and modified swimming bladder were found. In addition, to splenomegaly and ascites containing mucous-yellow fluid, deposition of sanguineous fluid in the abdominal cavity, hyperemia, enlargement of the gallbladder, abdominal cavity with swelling and small areas of liver hemorrhage were observed. These characterization of clinical signs related with polymicrobial infections can help fish farmers in the early identification of diseases, allowing thus the appropriate management of treatment. Therefore, further studies are needed to better understand the immune response of these fish during mixed bacterial infections, because these may have a major impact on the development of new strategies for disease control and vaccination programs in this fish to mitigate the bacteriosis in fish farms

The Use of Phage-Displayed Peptide Libraries to Develop Tumor-Targeting Drugs

Monoclonal antibodies have been successfully utilized as cancer-targeting therapeutics and diagnostics, but the efficacies of these treatments are limited in part by the size of the molecules and non-specific uptake by the reticuloendothelial system. Peptides are much smaller molecules that can specifically target cancer cells and as such may alleviate complications with antibody therapy. Although many endogenous and exogenous peptides have been developed into clinical therapeutics, only a subset of these consists of cancer-targeting peptides. Combinatorial biological libraries such as bacteriophage-displayed peptide libraries are a resource of potential ligands for various cancer-related molecular targets. Target-binding peptides can be affinity selected from complex mixtures of billions of displayed peptides on phage and further enriched through the biopanning process. Various cancer-specific ligands have been isolated by in vitro, in vivo, and ex vivo screening methods. As several peptides derived from phage-displayed peptide library screenings have been developed into therapeutics in current clinical trials, which validates peptide-targeting potential, the use of phage display to identify cancer-targeting therapeutics should be further exploited