Schistosomicidal Activity of the Essential Oil of Ageratum conyzoides L. (Asteraceae) against Adult Schistosoma mansoni Worms

The in vitro schistosomicidal effects of the essential oil of Ageratum conyzoides L. (Ac-EO) against adult worms of Schistosoma mansoni is reported in this paper. Concerning this activity, Ac-EO was considered to be active, but less effective than the positive control (praziquantel, PZQ) in terms of separation of coupled pairs, mortality, decrease in motor activity, and tegumental alterations. However, Ac-EO caused an interesting dose-dependent reduction in the number of eggs of S. mansoni. Precocene I (74.30%) and (E)-caryophyllene (14.23%) were identified as the two major constituents of Ac-EO. These compounds were tested individually and were found to be much less effective than Ac-EO and PZQ. A mixture of the two major compounds in a ratio similar to that found in the Ac-EO was also less effective than Ac-EO, thus revealing that there are no synergistic effects between these components. These results suggest that the essential oil of A. conyzoides is very promising for the development of new schistosomicidal agents.

A small area 8 bits 50 MHz CMOS DAC for Bluetooth transmitter

This paper presents a small-area CMOS current-steering segmented digital-to-analog converter (DAC) design intended for RF transmitters in 2.45 GHz Bluetooth applications. The current-source design strategy is based on an iterative scheme whose variables are adjusted in a simple way, minimizing the area and the power consumption, and meeting the design specifications. A theoretical analysis of static-dynamic requirements and a new layout strategy to attain a small-area current-steering DAC are included. The DAC was designed and implemented in 0.35 mu m CMOS technology, requiring an active area of just 200 mu m x 200 mu m. Experimental results, with a full-scale output current of 700 mu A and a 3.3 V power supply, showed a spurious-free dynamic range of 58 dB for a 1 MHz output sine wave and sampling frequency of 50 MHz, with differential and integral nonlinearity of 0.3 and 0.37 LSB, respectively.

Schistosomicidal Evaluation of Zanthoxylum naranjillo and its Isolated Compounds against Schistosoma mansoni Adult Worms

Chemical investigation of the EtOAc fraction (EF) obtained from the ethanolic extract of Zanthoxylum naranjillo (Rutaceae) leaves (EE) by preparative HPLC resulted in the isolation of protocatechuic acid (1), gallic acid (2), p-hydroxybenzoic acid (3), and 5-O-caffeoylshikimic acid (4). This is the first time that the presence of compounds 1-4 in Z. naranjillo has been reported. Compounds 1-4, the EE, and EF were tested in vitro against Schistosoma mansoni adult worms. The results showed that the S. mansoni daily egg production decreased by 29.8%, 13.5% 28.4%, 17.7%, 16.3%, and 6.4%, respectively. Compounds 1 and 3 were also able to separate adult worm pairs into male and female. This activity may be correlated with the reduction in egg production, since 1 and 3 showed better inhibitory properties compared with 2 and 4.

Australian Glow-worms in Caves

Glow-worms are the larvae of a fly from the family Keroplatidae. Their closest relatives are the “fungus flies” that seek out mushrooms for their larvae to consume. Glow-worms have gone out on an evolutionary limb, albeit a successful one. They have lost their association with fungi and have instead become carnivorous. The unique feature of glow-worms is their ability to bioluminesce—to produce light.

Glow worms as a tourist attraction in Springbrook National Park: Visitor attitudes and economic issues

nsect-based tourism mainly caters to a niche market, but its popularity has been growing in recent years. Despite its popularity this form of tourism has remained under-researched and in a sense its contribution to the tourism industry has gone mostly unnoticed. This paper reports the results of a study undertaken on one form of popular insect-based tourism, namely glow worms. The study was undertaken in Springbrook National Park (Natural Bridge section) southeast Queensland, which has one of the largest glow worm colonies in Australia that attracts thousands of visitors each year. A study of this form of tourism is important and useful for several reasons. It is important to understand this hitherto under-studied tourism activity to determine the type of visitors, their socio-economic attributes, economic benefits to the local economy, visitors’ knowledge of glow worms, education imparted, visitor satisfaction of glow worm viewing and visitor attitudes for the introduction of a user fee system to view glow worms. An understanding of these issues could not only help to better manage this valuable biological resource, but can be used to develop the industry to cater to a growing number of visitors. Tourism in glow worms can potentially be used not only to educate the public on the threats affecting glow worms and their colonies, but could also be used to conserve them. Lessons learnt from glow worms as an attraction to Springbrook National Park can be used to better manage and further develop other existing and new glow worm sites in Australia and elsewhere for tourism. Furthermore, it could provide some guidance for the management and development of other forms of current insect-based tourism activities (eg. butterflies) and develop new tourism ventures based on species such as stick insects and jewel beetles for which Australia is well known (Reader’s Digest, 1997)

In vitro schistosomicidal effects of some phloroglucinol derivatives from Dryopteris species against Schistosoma mansoni adult worms

The rhizomes of Dryopteris species have popularly been used as vermifuge in flatworm infections. The aim of this work was to evaluate the in vitro schistosomicidal activity of some phloroglucinol compounds, obtained from the rhizomes of Dryopteris species, against Schistosoma mansoni adult worms. All worm pairs were dead after 24 h of incubation with aspidin 25 to 100 mu M (1), flavaspidic acid 50 and 100 mu M (2), methylene-bis-aspidinol 100 mu M (3), and desaspidin 25 to 100 mu M (4). Worms incubated with 1 (25 to 100 mu M) and 2 (50 to 100 mu M) showed decrease motor activity with tegumental alterations, while 3 (100 mu M) and 4 (10 to 100 mu M) showed decrease motor activity without tegumental alterations. Desaspidinol (5) and filicinic acid (6), at the tested concentrations (10 to 100 mu M), did not show activity against adult worms of S. mansoni. Praziquantel (10 mu M), used as positive control, caused death of the parasites and tegumental alterations without separation of worms. In the groups treated with 100 A mu M of compounds 1-4, the viability of the adult worms was similar to the positive control group, in which the worms were dead. Also, both the egg productions and the development of eggs produced by the adult worms were inhibited by the incubation with compounds 1-4 (10 and 100 mu M) in comparison with the negative control (RPMI 1640 medium). It is suggested that the in vitro schistosomicidal effects of phloroglucinols derivatives 1, 2, 3, and 4 may be related to the inhibition of oxidative phosphorylation pathway in S. mansoni. The present results confirmed the traditional indications of rhizomes from Dryopteris species, which possess phloroglucinol compounds, in the treatment of tapeworm infections.

In vitro schistosomicidal activity of curcumin against Schistosoma mansoni adult worms

The in vitro schistosomicidal activity of curcumin (doses ranging from 5 to 100 mu M) was carried out against Schistosoma mansoni adult worms. Curcumin (at 50 and 100 mu M) caused death of all worms. When tested at the doses of 5 and 20 mu M, it decreased the worm viability in comparison with negative (Roswell Memorial Park Institute (RPMI) 1640 medium alone or RPMI 1640 medium with 10% dimethyl sulfoxide) and positive (heat-killed worms at 56A degrees C or praziquantel 10 mu M) control groups. All pairs of coupled adult worms were separated into individual male and female by the action of curcumin at the doses of 20 to 100 mu M. When tested at 5 and 10 mu M, curcumin reduced egg production by 50% in comparison with the positive control group. It is the first time that the schistosomicidal activity has been reported for curcumin.

Dam worms

Human and animal infection rates with the Oriental schistosome have steadily declined in China over the last half-century, but the Three Gorges Dam may reverse this decline by creating new, or enlarging existing, ideal environments for the worm and its aquatic snail intermediate host.

: acquired resistance in mice by implantation of young irradiated worms into the portal system

In two distinct experiments, immature S. mansoni worms (LE strain, Belo Horizonte, Brazil), aged 20 days, obtained from the portal system of white outbred mice, were irradiated with 14 and 4 Krad, respectively. Afterwards, the worms were directly inoculated into the portal vein of normal mice. Inoculation was performed with 20 irradiated worms per animal. Fifty days after inoculation, the mice that received 4 and 14 Krad-irradiated worms and their respective controls were infected with S. mansoni cercariae (LE strain), by transcutaneous route. Twenty days after this challenge infection, the animals were sacrificed and perfused for mature irradiated (90-day-old) and immature (20-day-old) worm counts. Analysis of the results showed that statistically significant protection against cercariae occurred in both groups with irradiated worms.

Immunoelectrophoretic study on common antigens of São Lourenço da Mata and Belo Horizonte strains of Schistosoma mansoni adult worms and Biomphalaria snails

Immunoelectrophoretic studies on common antigens were carried out by using rabbits sera immunized against São Lourenço da Mata and Belo Horizonte strains of Schistosoma mansoni adult worms and antigens of Biomphalaria glabrata pigmented (Jaboatão - PE); B. glabrata albino (Belo Horizonte - MG) and B. straminea (São Lourenço da Mata, PE). Furthermore, the reverse approach was proceeded, namely, sera anti Biomphalaria snails produced in rabbits were tested against both strains of Schistosoma adult worm antigens. The analysis of the common antigens between the SLM strains of S. mansoni adult worm and B. glabrata pigmented showed 8 to 9 precipitin bands, 3 bands with B. glabrata albino and only 1 band with B. straminea crude extracts. On the other hand, the BH strain of S. mansoni adult worm antisera produced 6 to 7 bands with B. glabrata pigmented, 5 bands with B. glabrata albino and 1 band with B. straminea antigenic extract. Biomphalaria snails crude extracts were fractionated by Sephadex G-100 column and three fractions were collected from each snail strain. The fractions were tested with anti SLM and BH strains of S. mansoni adult worm sera by immunoelectrophoresis. The common antigens fractionated from Biomphalaria snails crude extracts and those found for both strains of S. mansoni adult worm mostly existed in the first fraction and they were estimated to have molecular weight over 158,000 daltons. In our laboratory, it was found a relationship between the antigenic similarities and experimental infection rates of S. mansoni towards Biomphalaria snails so that more bands were seen with increasing infection rates of S. mansoni.

Comparative study on the localization of adult Schistosoma mansoni worms in albino mice anesthetized with pentobarbital sodium, ether or chlorophorm

The effect of anesthetic drugs on the localization of adult worms in albino mice was compared. The animals with 56 days of infection were anesthetized with pentobarbital sodium, ether or chlorophorm. Perfusion was carried out immediately after, recovering the worms and classifying them in relation to their localization on the liver or portal vein and the mesenteric veins. Our results showed that pentobarbital sodium produced a greater displacement of the worms to the liver (89%) than ether (76%) and chlorophorm (34%) did, when compared to the control group (22%). The difference between pentobarbital sodium and ether was significant (p < 0.05). We suggest that anesthetic drugs may not be used in studies on the distribution of adult worms in several hosts.

Determinantes à receptividade ao bluetooth marketing pelo consumidor português

Dissertação de Mestrado apresentada ao Instituto Superior de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Marketing Digital, sob orientação do Mestre Paulo Gonçalves e da Doutora Madalena Vilas Boas Esta versão não contém as críticas e sugestões dos elementos do júri

Schistosoma mansoni: the sex ratios of worms in animals infected with cercariae from three species of Biomphalaria

The ratios of male to female worms of Schistosoma mansoni were determined in mice infected with cercariae from LE, SJ and AL strains shed by mollusc hosts of the parasite in Brazil. The sex ratios of worms in the animals were similar with cercariae from Biomphialaria glabrata and B. tenagophila varying from 1.1:1 to 1.6:1 with LE and AL strains and 1:1.1 with SJ. In the animals infected with cercariae from B. straminea the ratio of male to female worms was similar to those obtained using cercariae shed from the other two species of molluscs, 1.5:1 with LE strain. Inoculations by AL and SJ cercariae resulted in sex ratios of 3.1:1 and 6:1 respectively. The normal sex ratios of worms established in Brazil in animals inoculated with cercariae from B. glabrata and B. tenagophila is from 1:1 to 2:1. The higher number of male worms that developed from cercariae of the AL and SJ strains obtained from B. straminea indicate a lower compatibility of the snail concerning these strains of S. mansoni.