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A 38.5 kDa alkaline protease from pyloric caeca of tambaqui (Colossoma macropomumj, a tropical freshwater fish, was partially purified in three steps: thermal treatment (45Cfor 30 min), salting‐out (ammonium sulfate at 40–80% of saturation) and gel filtration (Sephadex G‐75), The purification and yield were 51.2‐fold and 40%, respectively. The effects of pH, temperature, inhibitors, and substrates on proteolytic activities of partially purified enzyme were investigated. The optimum pH was 9.5, while the optimum temperature was 60C. This alkaline proteolytic activity remained unaltered after 30 min incubation at 55C. Active site inhibition provided additional evidence that this activity is attributed to a trypsin‐like enzyme.

SUMMARYA serological survey of Toxoplasma gondii infection in blood donors was carried out in order to identify seroprevalence in Recife, Brazil. Sera from 160 individuals (119 male and 41 female) were evaluated by using a Toxoplasma IgG-antibody enzyme immunoassay (Denka Seiken Co., LTD., Tokyo, Japan). The seropositive percentual for males (79.0%) showed to be higher (p ≤ 0.05) than for females (63.4%). This percentage increases with age, ranging from 18.2% to 92.6% for individuals aging under 20 and 40-50 years old, respectively. For women of childbearing age (18-40 years) it was found a prevalence of 51.6%. KEYWORDS:Toxoplasmosis; Seroepidemiology; Human; Recife, Brazil.Toxoplasmosis is a disease caused by the ubiquitous protozoan parasite Toxoplasma gondii 5 . Most T. gondii infections among humans occur by ingestion of tissue cysts from infected meat or oocysts from soil, or by congenital transmission through the placenta 3,10 . According to NETO et al. 14 , Brazil presents the highest prevalence of congenital toxoplasmosis reported so far. Blood samples (140,914) from all over the country were tested for IgM-class antibodies and 47 cases confirmed. This finding suggests a prevalence of 1 per 3,000 births.Although toxoplasmosis is a worldwide dispersed infection, seropositivity levels vary widely among different regions of the globe 7 . The prevalence rates change according to socio-cultural habits, geographic factors, climate and transmission route, and typically rise with age 4,7 . In Brazil, prevalence studies have been carried out, mainly in the Amazon and southeast regions during the 70-80's. Seroprevalence ranged from 40-80%, with increasing levels according to age, low socioeconomic status, rural dwelling and raw meat cooking practices 16 .Serological surveys indicate that about 80% of all primary infections are asymptomatic, due to the immune system effectiveness, but variable levels of the disease can affect immunocompromised individuals 4 . The epidemic of Acquired Immune Deficiency Syndrome (AIDS) has created an expanding population of susceptible individuals. Usually, people suffering from both AIDS and toxoplasmosis have been exposed to the Toxoplasma parasite earlier in life and the HIV infection simply allowed the Toxoplasma parasite to grow unchecked. The concomitant occurrences should be considered by public health policies especially in those countries with high toxoplasmosis prevalence where AIDS is concurrent with economic and public health problems 15 . GUIMARÃES9 estimated the annual incidence of reported AIDSassociated opportunistic infections among AIDS cases at the national level in Brazil from 1980 through May 1999. The overall cumulative incidence rates/100 reported AIDS cases were: candidiasis -59, tuberculosis -26, Pneumocystis carinii pneumonia -23, neurotoxoplasmosis -15, Kaposi sarcoma -5, cryptococcal meningitis -4 and protozoa infections -4.In 2000, Recife occupied the 11 th position in number of AIDS cases reported (211) and 56 th in number of cases/100,000 inhabitants ...

A trypsin was purified from pyloric caeca of pirarucu (Arapaima gigas). The effect of metal ions and protease inhibitors on its activity and its physicochemical and kinetic properties, as well its N-terminal sequence, were determined. A single band (28.0 kDa) was observed by SDS-PAGE. Optimum pH and temperature were 9.0 and 65°C, respectively. The enzyme was stable after incubation for 30 min in a wide pH range (6.0-11.5) and at 55°C. The kinetic parameters K m , k cat and k cat /K m were 0.47 ± 0.042 mM, 1.33 s À1 and 2.82 s À1 mM À1 , respectively, using BApNA as substrate. This activity was shown to be very sensitive to some metal ions, such as Fe 2+ , Hg 2+ , Zn 2+ , Al 3+ , Pb 2+ , and was highly inhibited by trypsin inhibitors. The trypsin N-terminal sequence IVGGYECPRNSVPYQ was found. The features of this alkaline peptidase suggest that it may have potential for industrial applications (e.g. food and detergent industries).

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices.

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