Francisco Hiran Farias Costa

Agglutination of Enzyme Treated Erythrocytes by Brazilian Marine Algal Extracts.

Hemagglutinating activity of twenty-seven species of Brazilian marine algae (sixteen red, seven green and four brown) was determined using trypsin, papain, bromelain and subtilisin treated erythrocytes of human A, B, O and AB groups, in addition to those of chicken, goat, pig and rabbit. The treatment with trypsin was more effective for rabbit erythrocytes, while human red blood cells showed better agglutination when treated by papain, bromelain and subtilisin. Rabbit erythrocytes were agglutinated by twelve red, two green and one brown algal extracts. Enantioeladia duperreyi and Bryothamnion triquetrum extracts showed the highest agglutination of human treated erythrocytes

A new isolation procedure and further characterisation of the lectin from the red marine alga Ptilota serrata

Ptilota serrata has been shown previously to contain a lectin (PSL) which is non-specific for human blood groups. We report here a new isolation procedure for PSL using a single step affinity chromatography technique on cross-linked guar gum and further characterisation studies. PSL was inhibited by galactose and its derivatives. The carbohydrates o-nitrophenyl-N-acetyl-α-D-galactoside, p-nitrophenyl-N-acetyl-β-D-galactoside and lactose were strong inhibitors. The glycoproteins porcine stomach mucin, asialo bovine mucin and asialofetuin were also inhibitory. The Mr of PSL, determined by gel filtration, was 55,470. SDS-PAGE revealed one single protein band with Mr of 18,390, indicating the native protein to be a trimer of apparently identical subunits. PSL was shown to contain large amounts of acidic and hydroxyl amino acids but low in basic amino acids.

Induction and inhibition of human lymphocyte transformation by the lectin from the red marine alga Amansia multifida

Lectins are powerful stimulants of quiescent peripheral blood lymphocytes. They can induce blast transformation leading to mitosis of these cells in vitro. We report here the dose-dependent proliferative curve for human peripheral blood monouclear cells (PBMC) stimulated by the lectin amansin, from Amansia multifida. Amansin stimulated proliferation of (PBMC) at relatively low concentrations (3.12 to 12.5 µg mL-1). We observed also a gradual reduction in mitogenic capacity with progressive increase in the lectin concentration above 12.5 µg mL-1. This decrease in the mitogenic potential did not result from a toxic effect on the cells, and was predominant at a lectin concentration above 50 µg mL-1. This decrease in lymphocyte proliferation could be blocked by avidin and could not be overcome by IL-2 or another lectin (Con Br) at stimulatory concentrations. Additionally, we observed that cells incubated at stimulatory concentrations of amansin produced IFN-γ. Analysis of the culture supernatants established a direct correlation between the IFN-γ and the mitogenic and anti-mitogenic capacity of amansin.

A new survey of Brazilian marine algae for agglutinins

Aqueous protein extracts from 30 Brazilian marine algae were examined for haemagglutinating activity using native and enzyme-treated rabbit, chicken, sheep and human erythrocytes. Most extracts agglutinated at least one of the blood cells used. Sheep and rabbit erythrocytes were more suitable for detection of the agglutinating activity. The minimum protein concentration necessary to produce positive agglutination was usually lower with enzyme-treated erythrocytes than native ones. The five algal protein extracts showing the greatest haemagglutination titre were tested for sugar-binding specificity. Only the activity present in the green alga Cauler pacupressoides was inhibited by simple sugars and not by the glycoproteins tested. The activity of the other four extracts was inhibited by at least one of the glycoproteins utilised.

Differential induction of HSP-70 expression in response to IHHNV in white shrimp Litopenaeus vannamei naturally co-infected with IHHNV and IMNV

Brazil is becoming one of the main global producers of the shrimp Litopenaeus vannamei. Worldwide outbreaks of viral disease place this aquaculture industry at risk, causing episodic economical loss. The primary viruses for L. vannamei, particularly in northeastern Brazil, are the infectious hypodermal and hematopoietic necrosis virus (IHHNV) and the infectious myonecrosis virus (IMNV). After a period of unusual rainfall, we detected that farmed shrimp developing IMN or IHHN disease were co-infected with both viruses, and the disease outcome resulted from reciprocal IHHNV and IMNV proliferation. To comprehend how the key molecules of innate immunity respond to this double infection, the levels of HSP-70, crustin, penaeidin-3a, and C-type lectin-br1 were assessed by quantitative PCR. HSP-70 expression was expressively up-regulated by IHHNV infection in the gills of double-infected shrimp but not by IMNV infection; the other transcripts were not significantly altered. These findings implicate the HSP-70 as a differential modulator of viral co-infection in shrimp.

Low Salinity Facilitates the Replication of Infectious Myonecrosis Virus and Viral Co-Infection in the Shrimp Litopenaeus Vannamei

The white leg shrimp Litopenaeus vannamei has been converted commercially into the most predominant cultivated shrimp species in the world. However, such shrimp’s intensive farming worldwide propitiates outbreaks of epizootic diseases, primarily of viral etiology. In the principal Brazilian region of shrimp production, it is known that a reduction in the salinities of culture ponds causes the appearance of viral diseases. In the present work, we investigate the replication of the infection myonecrosis virus (IMNV) in controlled levels of salinity during the first 12 hours of infection. Using quantitative real-time PCR and statistical analysis, we verify that low salinity positively facilitates IMNV replication and proliferation by decreasing the generation time from 57.4 min (at 35 g L-1, optimum salinity) to 25.2 min at (5 g L-1, stressing concentration). Similarly, a positive relationship was demonstrated between a decrease in salinity and the reduction in the generation time of persistent infectious hypodermal and hematopoietic necrosis virus, a virus that usually co-infects shrimp in farm ponds.

Technical and Environmental Analysis of Shrimp Farming in the Coreau River Estuary, Ceara State, Brazil

Compared with other countries, the Brazilian shrimp aquaculture had a moderate development occupying an area of less than 20,000 hectares. Despite the importance of shrimp farming in rural economy developing, many critics unproven technical and/or scientific have been made due to possible environmental and social impacts of this industry. The objective of this study was to evaluate the technical, social and environmental aspects of shrimp farming in the Coreau river estuary, Ceara, Brazil. The focus was on the operating characteristics of shrimp farms. Results indicate that no shrimp farm was constructed on mangrove areas and no significant environmental impacts regarding water pollution were detected. However, it is interesting to identify technologically and economically feasible options for to resolve or mitigate the negative environmental impact of a future expansion of shrimp farms in this region.