Determination of moisture content and water activity in algae and fish by thermoanalytical techniques

The water content in seafoods is very important since it affects their sensorial quality, microbiological stability, physical characteristics and shelf life. In this study, thermoanalytical techniques were employed to develop a simple and accurate method to determine water content (moisture) by thermogravimetry (TG) and water activity from moisture content values and freezing point depression using differential scanning calorimetry (DSC). The precision of the results suggests that TG is a suitable technique to determine moisture content in biological samples. The average water content values for fish samples of Lutjanus synagris and Ocyurus chrysurus species were 76.4 ± 5.7% and 63.3 ± 3.9%, respectively, while that of Ulva lactuca marine algae species was 76.0 ± 4.4%. The method presented here was also successfully applied to determine water activity in two species of fish and six species of marine algae collected in the Atlantic coastal waters of Bahia, in Brazil. Water activity determined in fish samples ranged from 0.946 - 0.960 and was consistent with values reported in the literature, i.e., 0.9 - 1.0. The water activity values determined in marine algae samples lay within the interval of 0.974 - 0.979.

Chemical constituents from red algae Bostrychia radicans (Rhodomelaceae): new amides and phenolic compounds

This study describes the isolation and structural determination of two amides, isolated for the first time: N,4-dihydroxy-N-(2'-hydroxyethyl)-benzamide (0.019%) and N,4-dihydroxy-N-(2'-hydroxyethyl)-benzeneacetamide (0.023%). These amides, produced by the red macroalgae Bostrychia radicans, had their structures assigned by NMR spectral data and MS analyses. In addition, this chemical study led to the isolation of cholesterol, heptadecane, squalene, trans-phytol, neophytadiene, tetradecanoic and hexadecanoic acids, methyl hexadecanoate and methyl 9-octadecenoate, 4-(methoxymethyl)-phenol, 4-hydroxybenzaldehyde, methyl 4-hydroxybenzeneacetate, methyl 2-hydroxy-3-(4-hydroxyphenyl)-propanoate, hydroquinone, methyl 4-hydroxymandelate, methyl 4-hydroxybenzoate, 4-hydroxybenzeneacetic acid and (4-hydroxyphenyl)-oxo-acetaldehyde. This is the first report concerning these compounds in B. radicans, contributing by illustrating the chemical diversity within the Rhodomelaceae family.

Monostromatic green algae (Ulvales, Chlorophyta) of São Paulo and Paraná states (Brazil): distribution, growth, and reproduction

(Monostromatic green algae (Ulvales, Chlorophyta) of São Paulo and Paraná states (Brazil): distribution, growth, and reproduction). Culture studies were used for taxa identification and to understand aspects of the biology and physiology of monostromatic green blades growing in various sites along the coast of São Paulo state (23º30'-25ºl2'S, 45º10'-48ºW) and one site in Paraná state (25º35'S, 48º21'W), southeast and south Brazil, respectively. Possible variations of the growth rate, age of reproduction and life history were tested under different conditions of temperature, salinity and day length. Two species were found: Ulvaria oxysperma (Kützing) Bliding and Monostroma sp. The first one has been previously reported for many temperate and tropical estuaries around the world. Green monostromatic blades with the same life-history and ontogeny as Monostroma sp. have been reported so far only for the tropical coast of Brazil. Species are distinct in their ontogeny of the thallus (constant under different conditions) and limiting temperatures of survival. U. oxysperma grows and reproduces from 10 to 25ºC and dies when maintained at 30ºC; Monostroma sp. does not reproduce at 15ºC and survives at 30ºC. The different salinities and day lengths that were tested had no significant effect on either species.

The effect of water stress on seed germination of three terrestrial bromeliads from restinga

Bromeliad seedlings are rarely found on sandy coastal plains (restinga), limited, probably, by stressful conditions and/or specific abiotic requirements for germination. The effect of water stress on rate, time, synchronicity and spreading of germination was evaluated here for three terrestrial bromeliads from the restinga of Maricá using osmotic solutions of polyethyleneglicol 6000 (PEG 6000), from 0.0 to -0.26 MPa for 30 days. Water stress induced by PEG lowered rate and increased time and synchronicity values, besides the number of daily events of bromeliad seed germination, under water potentials between 0.00 to -0.14 MPa. No seeds germinated under water potentials lower than -0.14 MPa. These results reinforce a constant and/or high moisture requirement for bromeliad seeds to germinate. We conclude that bromeliads are not able to act as pioneer plants through germination outside the vegetation islands of the restinga of Maricá, due to the inability of seeds to germinate under lower water potential.

Corticolous cyanobacteria from tropical forest remnants in northwestern São Paulo State, Brazil

Cyanobacteria are common in aquatic environments but are also well-adapted to terrestrial habitats where they are represented by a diversified flora. The present study aimed to contribute to our taxonomic knowledge of terrestrial cyanobacteria by way of a floristic survey of the main components of corticolous communities found in seasonal semideciduous forest fragments. Samples of visible growths of Cyanobacteria, algae, and bryophytes found on tree bark were randomly collected and their taxonomies examined. Eighteen species of Cyanobacteria were found belonging to the genera Aphanothece, Chroococcus, Lyngbya, Phormidium, Porphyrosiphon, Hapalosiphon, Hassalia, Nostoc, Scytonema, and Stigonema. Many genera and species observed in the present work have been reported in previous surveys of the aerophytic flora in several regions of the world, although six species were described only on the basis of populations found in the forest fragments studied, which highlights the importance of taxonomic studies of cyanobacteria in these habitats.

Antinociceptive activity of sulfated carbohydrates from the red algae Bryothamnion seaforthii (Turner) Kütz. and B. triquetrum (S.G. Gmel.) M. Howe

We report the antinociceptive activity, determined by the writhing, formalin and hot-plate tests in mice, of crude (F0/60), lectin and carbohydrate fractions isolated by ammonium sulfate precipitation (0 to 60%) from Bryothamnion seaforthii and B. triquetrum, species of red algae. Not only fraction F0/60 but also lectins from both species significantly inhibited acetic acid-induced abdominal contractions after intraperitoneal or oral administrations. In the formalin test, lectins (1 and 5 mg/kg, ip, and 5 to 20 mg/kg, po) inhibited the 1st and 2nd phases (5 and 20 min, respectively), but the effect occurred predominantly on the 2nd phase. The effects of the lectins were totally or partially reversed by naloxone (2 mg/kg, sc) in the 1st and 2nd phases, respectively. Experiments performed with lectins in the absence and presence of avidin (1 mg/kg, ip) and D-mannose (1 mg/kg, ip) showed that avidin did not interfere with the effect of B. seaforthii lectin but partially reversed the effect of B. triquetrum lectin. D-Mannose completely reversed the effects of both species. F0/60 fractions from both algae significantly increased the latency time in response to thermal stimuli, and naloxone reversed antinociception, indicating the involvement of the opioid system in both the peripheral and central effects of the fractions. In the writhing test, the carbohydrate fractions were the most active, inhibiting the contractions by 71 and 79% (B. triquetrum) and by 46 and 69% (B. seaforthii) at doses of 1 and 5 mg/kg, ip, respectively. Sulfated carbohydrate fractions of B. seaforthii and B. triquetrum, containing only about 5% protein as contaminants, are probably responsible for the antinociceptive effects of these red algae.

The terrestrial Gastropoda Megalobulimus abbreviatus as a useful model for nociceptive experiments: effects of morphine and naloxone on thermal avoidance behavior

We describe the behavior of the snail Megalobulimus abbreviatus upon receiving thermal stimuli and the effects of pretreatment with morphine and naloxone on behavior after a thermal stimulus, in order to establish a useful model for nociceptive experiments. Snails submitted to non-functional (22ºC) and non-thermal hot-plate stress (30ºC) only displayed exploratory behavior. However, the animals submitted to a thermal stimulus (50ºC) displayed biphasic avoidance behavior. Latency was measured from the time the animal was placed on the hot plate to the time when the animal lifted the head-foot complex 1 cm from the substrate, indicating aversive thermal behavior. Other animals were pretreated with morphine (5, 10, 20 mg/kg) or naloxone (2.5, 5.0, 7.5 mg/kg) 15 min prior to receiving a thermal stimulus (50ºC; N = 9 in each group). The results (means ± SD) showed an extremely significant difference in response latency between the group treated with 20 mg/kg morphine (63.18 ± 14.47 s) and the other experimental groups (P < 0.001). With 2.5 mg/kg (16.26 ± 3.19 s), 5.0 mg/kg (11.53 ± 1.64 s) and 7.5 mg/kg naloxone (7.38 ± 1.6 s), there was a significant, not dose-dependent decrease in latency compared to the control (33.44 ± 8.53 s) and saline groups (29.1 ± 9.91 s). No statistically significant difference was found between the naloxone-treated groups. With naloxone plus morphine, there was a significant decrease in latency when compared to all other groups (minimum 64% in the saline group and maximum 83.2% decrease in the morphine group). These results provide evidence of the involvement of endogenous opioid peptides in the control of thermal withdrawal behavior in this snail, and reveal a stereotyped and reproducible avoidance behavior for this snail species, which could be studied in other pharmacological and neurophysiological studies.

Comparison of small mammal prevalence of Leishmania (Leishmania) mexicana in five foci of cutaneous leishmaniasis in the State of Campeche, Mexico

In the Yucatan Peninsula of Mexico, 95% of the human cases of Cutaneous Leishmaniasis are caused by Leishmania (Leishmania) mexicana with an incidence rate of 5.08 per 100,000 inhabitants. Transmission is limited to the winter months (November to March). One study on wild rodents has incriminated Ototylomys phyllotis and Peromyscus yucatanicus as primary reservoirs of L. (L.) mexicana in the focus of La Libertad, Campeche. In the present study, the prevalence of both infection and disease caused by L. (L.) mexicana in small terrestrial mammals were documented during five transmission seasons (1994-2004) in five foci of Leishmaniasis in the state of Campeche. Foci separated by only 100 km, with similar relative abundances of small mammals, were found to differ significantly in their prevalence of both symptoms and infection. Transmission rates and reservoir species seemed to change in space as well as in time which limited the implementation of effective control measures of the disease even in a small endemic area such as the south of the Yucatan Peninsula.

Antiviral activity of the green marine alga Ulva fasciata on the replication of human metapneumovirus

We evaluated the antiviral activity of the marine alga, Ulva fasciata, collected from Rasa beach and Forno beach, Búzios, Rio de Janeiro, Brazil on the replication of human metapneumovirus (HMPV). The algae extracts were prepared using three different methodologies to compare the activity of different groups of chemical composites obtained through these different methodologies. Four out of the six extracts inhibited nearly 100% of viral replication. The results demonstrated that the majority of the extracts (five out of six) possess virucidal activity and therefore have the ability to interact with the extracellular viral particles and prevent the infection. On the other hand, only two extracts (from Forno beach, obtained by maceration and maceration of the decoction) were able to interact with cell receptors, hindering the viral entry. Finally, only the extract of algae collected at Forno beach, obtained by maceration presented intracellular activity. To our knowledge, this is a pioneer study on antiviral activity of marine algae against HMPV. It is also the first on antiviral activity against HMPV ever done in Brazil. The study also shows the effect of different environment factors and different chemical procedures used to obtain the extract on its biological properties.

In vitro antimalarial activity and cytotoxicity of some selected cuban medicinal plants

Terrestrial plants have been demonstrated to be sources of antimalarial compounds. In Cuba, little is known about antimalarial potentials of plant species used as medicinals. For that reason, we evaluated the antimalarial activity of 14 plant species used in Cuba as antimalarial, antipyretic and/or antiparasitic. Hydroalcoholic extracts were prepared and tested in vitro for the antimalarial activity against Plasmodium falciparum Ghana strain and over human cell line MRC-5 to determine cytotoxicity. Parasite multiplication was determined microscopically by the direct count of Giemsa stained parasites. A colorimetric assay was used to quantify cytotoxicity. Nine extracts showed IC50 values lower than 100 µg/mL against P. falciparum, four extracts were classified as marginally active (SI < 4), one as partially active (Parthenium hysterophorus) exhibiting SI equal to 6.2 and two extracts as active (Bambusa vulgaris and Punica granatum), showing SI > 10. B. vulgaris showed the most potent and specific antiplasmodial action (IC50 = 4.7 µg/mL, SI = 28.9). Phytochemical characterization of active extracts confirmed the presence of triterpenoids in B. vulgaris and polar compounds with phenol free groups and fluorescent metabolites in both extracts as major phytocompounds, by thin layer chromatography. In conclusion, antimalarial use of B. vulgaris and P. hysterophorus was validated. B. vulgaris and P. granatum extracts were selected for follow-up because of their strong antimalarial activity.

MOLLUSCICIDAL AND LARVICIDAL ACTIVITIES OF Atriplex inflata AERIAL PARTS AGAINST THE MOLLUSK Galba truncatula, INTERMEDIATE HOST OF Fasciola hepatica

Fasciolosis is a widespread parasitosis of farm live-stock in many developing countries. For this reason, it is necessary to search for new substances against parasitic diseases caused by flukes. Indeed, a wide variety of terrestrial plants have been subjected to chemical and pharmacological screening in order to discover their potential for human medicinal use. The molluscicidal and larvicidal activities of Atriplex inflata were tested on Galba truncatula and Fasciola hepatica larval stages infecting this snail in Tunisia. Phytochemical tests were conducted on extracts in order to establish a meaningful relationship with molluscicidal and larvicidal activities. The molluscicidal activity was evaluated by subjecting snails to sample aqueous solutions. Accordingly, hexane, ethyl acetate, methanol and methanol-water (8:2, v-v) were used as extraction solvents. As a result, hexane and ethyl acetate extracts showed potent activity, according to the World Health Organization, giving LC50 = 7.59 mg/L and 6.69 mg/L for hexane extracts of leaves and fruits, respectively. Ethyl acetate extracts gave LC50 = 5.90 mg/L and 7.32 mg/L for leaves and fruits, successively. Molluscicidal activities of powders were less potent on snails, but active according to the World Health Organization. Hexane and ethyl acetate extracts from leaves and fruits gave potent larvicidal activities with a delay rate exceeding 45.50% (45.50- 98.92%). Phytochemical tests showed that these activities may be attributed to the presence of triterpenoids and/or sterols.

Molecular characterization of rabies virus isolated from non-haematophagous bats in Brazil

INTRODUCTION: Rabies is an important zoonosis that causes thousands of deaths worldwide each year. Although the terrestrial cycle, mainly transmitted by dogs, is controlled in Brazil, the aerial cycle remains a serious public health issue, besides the economic problem. In the aerial cycle, the haematophagous bat Desmodus rotundus is the main source of infection, where several different species of non-haematophagous bats can be infected and can transmit the virus. METHODS: The aim of this work was to study the epidemiological pattern of rabies using antigenic characterization with monoclonal antibodies and genetic characterization by reverse-transcriptase polymerase chain reaction followed by sequencing and phylogenetic analysis of non-haematophagous bats' and herbivorous animals' central nervous system samples from the western region of the State of São Paulo, Brazil. RESULTS: From 27 samples, 3 antigenic variants were identified: AgV-3, AgV-4, and AgV-6; and from 29 samples, 5 different clusters were identified, all belonging to the rabies virus species. CONCLUSIONS: Although only non-haematophagous bats were evaluated in the studied region, the majority of samples were from antigenic and genetic variants related to haematophagous bats Desmodus rotundus. Samples from the same antigenic variant were segregated in more than one genetic cluster. This study demonstrated the diversity of rabies virus genetic lineages presented and circulating in non-haematophagous bats in the studied region.

Detection of arboviruses of public health interest in free-living New World primates (Sapajus spp.; Alouatta caraya) captured in Mato Grosso do Sul, Brazil

Introduction A sero-epidemiological survey was undertaken to detect the circulation of arboviruses in free-living non-human primates. Methods Blood samples were obtained from 16 non-human primates (13 Sapajus spp. and three Alouatta caraya) that were captured using terrestrial traps and anesthetic darts in woodland regions in the municipalities of Campo Grande, Aquidauana, Jardim, Miranda and Corumbá in the State of Mato Grosso do Sul, Brazil. The samples were sent to the Instituto Evandro Chagas (IEC) in Ananindeua, Pará, Brazil, to detect antibodies against 19 species of arboviruses using a hemagglutination inhibition test (HI). Results Of the 16 primates investigated in the present study, five (31.2%) were serologically positive for an arbovirus. Of these five, two (12.5%) exhibited antibodies to the Flavivirus genus, one (6.2%) exhibited a monotypic reaction to Cacipacoré virus, one (6.2%) was associated with Mayaro virus, and one (6.2%) was positive for Oropouche virus. Conclusions Based on the positive serology observed in the present study, it was possible to conclude that arboviruses circulate among free-living primates. The viruses in the areas studied might have been introduced by infected humans or by primates from endemic or enzootic areas. Studies of this nature, as well as efficient and continuous surveillance programs, are needed to monitor viral activities in endemic and enzootic regions.

The algal flora of two distinct habitats along the Moa River in the state of Acre, Brazil

Twenty-eoght algal samples were collected in September-October, 1984, from two distinct habitats in the state of Acre, Brazil. Eleven were from the Moa River, and 17 were from a sulfur water spring which flows into the Moa River. A total of 74 species, representing 48 genera of algae, were identified from these samples. Forty-nine species were found in the Moa River and 67 in the sulfur water spring. Both coolection site had rich assemblages of cyanophycean algae, chlorophycean algae, and diatoms. Chlorophycean species dominated the algae flora at both sites, cut were more numerous at the sulfur water spring. There was also a definite difference in the relatives proportions of desmids to filamentous chlorophycean algae at the two sites.

Small mammal abundances in isolated and non-isolated primary forest reserves near Manaus, Brazil

Abundances of msmall terrestrial mammals were estimated in 10 and 100-ha, isolated and non-isolated primary forest reserves near, Manaus, Brazil between October 1983 and March 1984. The smalt mammal abundance pattern In a 10 ha reserve isolated fan appoximately three years differed significantly from that in othen reserves, primarily due to higher capture rates of Marmosa cinerea, Rhipidomys mastacalis, and Onyzomys paricola in the isolated reserve. Viet type and re-invasion potential may be important factors the small mammal communities in forest patches. Variation the small mammal community among othen reserves was pnimanlty due to variatton In the abundances of Proechimys and 0. capito. At least pant of this vantation was attributable to temporal efects, but variation due to reserve effects also was suggested. Small mammals were much more abundant in the reserves during the present study than in 1982.