Differences of susceptibility of five triatomine species to pyrethroid insecticides - implications for Chagas disease vector control

As pyrethroids are presently the favored group of insecticides to control triatomines, we performed a series of bioassays to determine the intrinsic activity of some of the main compounds used in the control campaigns, against five of the main species of triatomines to be controlled. Comparing the insecticides it can be seen that lambdacyhalothrin is more effective than the other three pyrethroids, both considering the LD50 and 99 for all the three species with comparable results. On Triatoma infestans the LD50 of lambdacyhalothrin was followed by that of alfacypermethrin, cyfluthrin and deltamethrin. On Rhodnius prolixus the sequence, in decreasing order of activity, was lambdacyhalothrin, alfacypermethrin, deltamethrin and cyfluthrin. Some modifications can be seen when we compare the LD99, that has more to see to what happens in the field. T. brasiliensis showed to be as sensible to lambdacyhalothrin as T. infestans, the most susceptible for this product. By the other side T. sordida is the least susceptible considering the LD99 of this insecticide.     

Expression and purification of the recombinant SALT lectin from rice (Oryza sativa L.)

The SALT protein is a 14.5 kDa mannose-binding lectin, originally described as preferentially expressed in rice plant roots in response to NaCl stress. Recombinant SALT lectin was produced in Escherichia coli from a cDNA clone encoding protein. After isopropyl-beta-d-thiogalactopyranoside induction, the expression level achieved was 23% of the soluble protein. The recombinant agglutinin was purified by a single-step process by dialyses against a high concentrated salt solution. After purification, hemagglutination assays of rabbit erythrocytes revealed that the recombinant SALT protein is a potent agglutinin (0.078 microg ml(-1) minimal concentration). The purified recombinant lectin was also used for comparative estimation of native protein amounts in protein extracts from rice plants by Western blot assay.     

Modeling of a bipedal locomotor using coupled nonlinear oscillators of Van der Pol

 Research to date points to an understanding of human biped locomotion that has been primarily experimental in nature largely due to the complexity of the process. In view of the new, exciting possibilities of programmed electrostimulation of artificial muscles to generate motion (locomotion), a critical study at the theoretical level is greatly warranted. There is strong evidence that many biological clocks consist of a population of mutually coupled oscillators [Pavlidis T (1973) Biological oscillators, Academic; Johnsson A (1978) Zur Biophysik biologischer Oszillatoren. In: Biophisik, Springer]. In this work, a form of bipedal locomotion is simulated by using mutually coupled nonlinear oscillators. A planar model, which includes three out of the six determinants of gait that characterize the human locomotion, was adopted. Received: 4 August 2002 / Accepted: 12 November 2002 / Published online: 7 March 2003 Correspondence to: M. S. Dutra (e-mail: max@serv.com.ufrj.br) Acknowledgements. The authors would like to express their gratitude to CNPq, CAPES, and FAPERJ for the financial support provided during the course of this research.     

Application of protease from Nocardiopsis sp. as a laundry detergent additive

The application of protease as a laundry detergent additive from a newly isolated Nocardiopsis sp., isolated from a soil sample collected in Northeast Brazil is reported. The optimal pH and temperature for protease activity were pH 10.5 and 50 °C, respectively. The enzyme was stable in a long-term incubation, showed 73.5% of initial activity at pH 10.5 and 61.7% at pH 12.0 for 120 min. Approximately 60% of initial activity remained after 120 min at 50 °C or after 30 min at 80 °C. Almost 87% of enzyme activity was retained in the presence of 10% (v/v) of peroxide at 40 °C, after 1 h. The protease also was stable in the presence of oxidants and surfactants such as SDS, saponin, Tween 20 and Tween 80 after 30 min. In the presence of Omo^®, the enzyme retained 64% of its activity at 40 °C for 1 h. An increase in the proteolytic activity (6–17%) was observed with K⁺, Na⁺, and Mg⁺⁺ ions. At pH 8.0, the protease hydrolysed casein maximally (50 U/mg).     

Protective properties of butanolic extract of the Calendula officinalis L. (marigold) against lipid peroxidation of rat liver microsomes and action as free radical scavenger

Calendula officinalis (marigold) has many pharmacological properties. It is used for the treatment of skin disorders, pain and also as a bactericide, antiseptic and anti-inflammatory. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are known to participate in the pathogenesis of various human diseases and may be involved in the conditions which C. officinalis is used to treat. The aim of this study was to investigate the relationship between the beneficial properties of this plant and its antioxidant action. The butanolic fraction (BF) was studied because it is non-cytotoxic and is rich in a variety of bioactive metabolites including flavonoids and terpenoids. Superoxide radicals (O(2)(*-)) and hydroxyl radicals (HO(*)) are observed in decreasing concentrations in the presence of increasing concentrations of BF with IC(50) values of 1.0 +/- 0.09 mg/ml and 0.5 +/- 0.02 mg/ml, respectively, suggesting a possible free radical scavenging effect. Lipid peroxidation in liver microsomes induced by Fe(2+)/ascorbate was 100% inhibited by 0.5 mg/ml of BF (IC(50) = 0.15 mg/ml). Its total reactive antioxidant potential (TRAP) (in microM Trolox equivalents) was 368.14 +/- 23.03 and its total antioxidant reactivity (TAR) was calculated to be 249.19 +/- 14.5 microM. The results obtained suggest that the butanolic fraction of C. officinalis possesses a significant free radical scavenging and antioxidant activity and that the proposed therapeutic efficacy of this plant could be due, in part, to these properties.     

Role of vascularization in determining the time of hypoxic-ischemic encephalopathy in the neonate

OBJECTIVE: To examine the role of vascularization in determining the time of hypoxic-ischemic encephalopathy (HIEP). STUDY DESIGN: Brain sections of 126 neonatal autopsy cases were examined for edema, gliosis, congestion, inflammation and ischemia. Capillary vessels were examined with both reticulum stains and antibody against CD34. Vascular surface density (VSD) and number of vessels per stroma (NVES) were calculated by stereologic methods. RESULTS: Among 126 cases, 64 were male (50.8%) and 62 female (49.2%). In 25 cases HIEP was observed; 14 had a pregnancy history of hypertension, eclampsia or diabetes mellitus in the mother, with fetal distress or underdeveloped features. Statistically, NVES was strongly related to primary HIEP. However, the HIEP and non-HIEP cases revealed no differences in NVES and VSD means. CONCLUSION: Vascularization, especially NVES, helps in determining whether an HIEP case is pregnancy related or due to end-stage changes of dying, but is not an indicator of HIEP.     

Redescription of Nyssomyia intermedia (Lutz & Neiva, 1912) and Nyssomyia neivai (Pinto, 1926) (Diptera: Psychodidae)

The phlebotomine sand flies Nyssomyia intermedia and Nyssomyia neivai are the probable vectors of American tegumentary leishmaniasis in the Southern and Southeastern regions of Brazil. These species form a complex, being difficult to separate between either females or males of the two members based on recognized morphological characteristics. Both N. intermedia and N. neivai are redescribed here in the search for characters that facilitate their correct identification. It was possible to differentiate females by means of spermathecal characteristics. Males could be separated with confidence by the tips of the genital filaments, which have the form of a deep spoon, the angle of the concavity being well accentuated in N. intermedia and much shallower in N. neivai.     

Modeling a particular decision process by using a modulatory activation function

Neuronal groups projecting widely in the brain are being experimentally associated to attention and mood changes. Those groups are known to exert a modulatory effect over other larger groups. On the other hand, some people think of the brain functions as being performed by specialized modular systems. In this work, we propose an architecture of modular nature to explore a particular decision process. We show the importance of the modulatory effect of a special evaluation segment in that process.     

Which Extent is Plasticity to Light Involved in the Ecotypic Differentiation of a Tree Species from Savanna and Forest?

Light intensity and heterogeneity are some of the main environmental factors that differ between forest and savanna habitats, and plant species from these habitats form distinct functional types. In this study, we tested the hypothesis that not only differences in morphological and physiological traits but also phenotypic plasticity in response to light are involved in adaptation to forest and savanna habitats by investigating ecotypic differentiation between populations of Plathymenia reticulata (Leguminosae: Mimosoideae), a tree from the Brazilian Atlantic Forest and the Brazilian Cerrado (savanna). Seeds from four natural populations (one from each biome core area and two from ecotonal regions) were grown in a common garden with four light treatments. Fifteen morphological and physiological characteristics were evaluated until individuals reached 6 mo old. Comparisons among populations showed differences for seven traits in at least one light treatment. These differences pointed to local adaptation to different biomes. Populations showed different levels of phenotypic plasticity in response to light in seven traits. Higher plasticity was found either in the forest core population or ecotonal populations; lower values were found in the cerrado core population. Lower plasticity in the cerrado population emphasizes the stress resistant syndrome, as lower plasticity is probably advantageous in a habitat where a conservative resource use is crucial. Higher plasticity in forest individuals suggests higher ability in exploiting the light heterogeneity in this habitat. Also, higher plasticity in ecotonal populations can be important to ensure the maintenance of P. reticulata in these temporally and spatially dynamic areas. Abstract in Portugese is available at http://www.blackwell‐synergy.com/loi/btp .     

A New Anaesthetic Protocol for Adult Zebrafish (Danio rerio): Propofol Combined with Lidocaine

Background

The increasing use of zebrafish model has not been accompanied by the evolution of proper anaesthesia for this species in research. The most used anaesthetic in fishes, MS222, may induce aversion, reduction of heart rate, and consequently high mortality, especially during long exposures. Therefore, we aim to explore new anaesthetic protocols to be used in zebrafish by studying the quality of anaesthesia and recovery induced by different concentrations of propofol alone and in combination with different concentrations of lidocaine.

Material and Methods

In experiment A, eighty-three AB zebrafish were randomly assigned to 7 different groups: control, 2.5 (2.5P), 5 (5P) or 7.5 μg/ml (7.5P) of propofol; and 2.5 μg/ml of propofol combined with 50, (P/50L), 100 (P/100L) or 150 μg/ml (P/150L) of lidocaine. Zebrafish were placed in an anaesthetic water bath and time to lose the equilibrium, reflex to touch, reflex to a tail pinch, and respiratory rate were measured. Time to gain equilibrium was also assessed in a clean tank. Five and 24 hours after anaesthesia recovery, zebrafish were evaluated concerning activity and reactivity. Afterwards, in a second phase of experiments (experiment B), the best protocol of the experiment A was compared with a new group of 8 fishes treated with 100 mg/L of MS222 (100M).

Results

In experiment A, only different concentrations of propofol/lidocaine combination induced full anaesthesia in all animals. Thus only these groups were compared with a standard dose of MS222 in experiment B. Propofol/lidocaine induced a quicker loss of equilibrium, and loss of response to light and painful stimuli compared with MS222. However zebrafish treated with MS222 recovered quickly than the ones treated with propofol/lidocaine.

Conclusion

In conclusion, propofol/lidocaine combination and MS222 have advantages in different situations. MS222 is ideal for minor procedures when a quick recovery is important, while propofol/lidocaine is best to induce a quick and complete anaesthesia.