Biological activity of neolignans on the post-embryonic development of Chrysomya megacephala.

Phytochemicals endowed with hormonal, antihormonal, or toxic activity are potential agents for insect control. The effect of some neolignans on one of the most prevalent flies in urban areas, which constitutes a menace to public health, was investigated.

[Digestive tract microbiota in female Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae) from colonies feeding on blood meal and sucrose plus blood meal]. / Microbiota do trato digestivo de fêmeas de Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae) provenientes de colônia alimentadas com sangue e com sangue e sacarose.

There are very few reports on the microbiota of the digestive tract of sand flies, an important omission considering that blood is not the only meal ingested. Male and female sand flies obtain sugar meals from several sources, thereby increasing their chance of infection with microorganisms. Chances of contamination are higher when insects are bred in the laboratory, and this may affect the development of Leishmania spp. From the digestive tract of 300 sand fly females separated in two groups we isolated 10 species of bacteria in group 1 and 8 species in group 2. In group 1, Enterobacteriaceae of the following genera were identified: Serratia, Enterobacter, and Yokenella and the non-fermenters: Pseudomonas, Acinetobacter, and Stenotrophomonas. In group 2, the Enterobacteriaceae Enterobacter and Serratia were identified as well as the non-fermenters Acinetobacter, Stenotrophomonas, Burkolderia, and Pseudomonas.

Ecology of mosquitoes (Diptera: Culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. III. Daily biting rhythms and lunar cycle influence.

The ecology of mosquito species (Diptera: Culicidae) was studied in areas of the Serra do Mar State Park, State of São Paulo, Brazil. The influence of the lunar cycle and the daily biting rhythms of mosquito populations were analyzed. Systematized biweekly human bait collections were made in a silvatic environment for 24 consecutive months (January 1991 to December 1992). A total of 20,591 specimens of adult mosquitoes belonging to 55 species were collected from 545 catches. Sabethini species were captured exclusively during daylight periods, with the exception of Trichoprosopon digitatum, while members of Anophelinae predominated during nocturnal hours. Members of the subfamily Culicinae that were collected primary during nocturnal periods included Culex nigripalpus, Coquillettidia chrysonotum and Cq. venezuelensis while daytime catches included Psorophora ferox and Ps. albipes. Others members of culicines mosquitoes that were collected during both day and night included: Aedes serratus, Ae. scapularis and Ae. fulvus. Lunar cycles did not appear to influence the daily biting rhythms of most mosquito species in the area, but larger numbers of mosquitoes were collected during the new moon. Ae. scapularis were captured mainly during the full moon.

[Prevalence of microbiota in the digestive tract of wild females of Lutzomyia longipalpis Lutz & Neiva, 1912) (Diptera: Psychodidae)]. / Prevalência da microbiota no trato digestivo de fêmeas de Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae) provenientes do campo.

We dissected the digestive tract of 245 females in pools of 35 flies forming 7 groups. These flies were Lutzomyia longipalpis originating from Lapinha Cave, Lagoa Santa, Minas Gerais. Out of the 8 species of bacteria isolated there was a predominancy of Gram negative bacterias (GNB) in the group of non-fermenters of sugar belonging to the following species: Acinetobacter lwoffii, Stenotrophomonas maltophilia, Pseudomonas putida and Flavimonas orizihabitans. The group of GNB fermenters were: Enterobacter cloacae and Klebsiella ozaenae. In the Gram positive group we isolated the genera Bacillus thuringiensis and Staphylococcus spp.

The effects of choline supplementation on physical performance.

It has been reported that plasma choline levels decrease following certain types of strenuous exercise. Preliminary findings also suggest that a drop in plasma choline may limit physical performance, while choline supplementation may delay fatigue during prolonged efforts. A double-blind crossover design was used to determine the relationship between plasma choline and performance during and after 4 hr of strenuous exercise. Volunteers (N = 14) received either a placebo or treatment beverage (8.425 g choline citrate) prior to and midway through a 4-hr load carriage treadmill exercise (3% grade at 5.6 km/h 3 20 km) carrying a total load of 34.1 kg. Following the treadmill test, run time-to-exhaustion and squat tests were performed, and perceived exertion, plasma choline, glycerophosphocholine, and phosphatidylcholine were measured. Plasma choline levels increased 128% after the run-to-exhaustion with the choline supplemented beverage but remained unchanged with the placebo beverage. No significant effects were seen with choline supplementation on any outcome performance measure. Consequently, soldiers conditioned to carry heavy loads over long distances do not deplete plasma choline as a result of a prolonged exhaustive exercise under a placebo beverage, nor do they benefit from choline supplementation to delay fatigue under the same conditions.

Ecology of mosquitoes (Diptera: culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. I - monthly frequency and climatic factors.

The ecology of mosquitoes were studied (Diptera: Culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. Systematized monthly human bait collections were made three times a day, for periods of 2 or 3 h each, in sylvatic and rural areas for 24 consecutive months (January 1991 to December 1992). A total of 24, 943 specimens of adult mosquitoes belonging to 57 species were collected during 622 collective periods. Coquillettidia chrysonotum was the most frequent collected mosquito (45.8%) followed by Aedes serratus (6.8%), Cq. venezuelensis (6.5%), Psorophora ferox (5.2) and Ps. albipes (3.1%). The monthly averages of temperature and relative humidity were inserted in the ten-year average limits of maximum and minimum of the previous ten-years. Rainfall accompanied the curve of the ten-year averages. Those climatic factors were influential in the incidence of some species; temperature: Anopheles cruzii, An. mediopunctatus, Ae. scapularis, Ae. fulvus, Cq. chrysonotum, Cq. venezuelensis, Runchomyia reversa, Wyeomyia dyari, Wy. confusa, Wy. shannoni, Wy. theobaldi and Limatus flavisetosus; relative humidity: Ae. serratus, Ae. scapularis, Cq. venezuelensis and Ru. reversa; rainfall: An. cruzii, Ae. scapularis, Ae. fulvus, Cq. venezuelensis Ru. reversa, Wy. theobaldi and Li. flavisetosus.

Ecology of mosquitoes (Diptera: Culicidae) in areas of Serra do Mar State Park, State of São Paulo, Brazil. II - habitat distribution.

The mosquito (Diptera: Culicidae) ecology was studied in areas of Serra do Mar State Park, State of São Paulo, Brazil. Systematized biweekly human bait collections were made three times a day, for periods of 2 or 3 h each, in sylvatic and rural areas for 24 consecutive months (January 1991 to December 1992). A total of 24, 943 adult mosquitoes belonging to 57 species were collected during 622 collective periods. Aedes scapularis, Coquillettidia chrysonotum, Cq. venezuelensis, Wyeomyia dyari, Wy. longirostris, Wy. theobaldi and Wy. palmata were more frequently collected at swampy and at flooded areas. Anopheles mediopunctatus, Culex nigripalpus, Ae. serratus, Ae. fulvus, Psorophora ferox, Ps. albipes and the Sabethini in general, were captured almost exclusively in forested areas. An. cruzii, An. oswaldoi and An. fluminensis were captured more frequently in a residence area. However, Cx. quinquefasciatus was the only one truly eusynanthropic. An. cruzii and Ae. scapularis were captured feeding on blood inside and around the residence, indicating that both species, malaria and arbovirus vectors respectively, may be involved in the transmission of these such diseases in rural areas.

Gender comparison of peak oxygen uptake: repetitive box lifting versus treadmill running.

The gender differences in peak oxygen uptake (VO2peak) for various modes of exercise have been examined previously; however, no direct gender comparisons have been made during repetitive lifting (RL). In the present study the VO2peak between RL and treadmill running (TR) was compared between 20 men [mean (SD) age, height, body mass and body fat: 21 (3) years, 1.79 (0.06) m, 81 (9) kg, 19 (6)%, respectively] and 20 women [mean (SD) age, height, body mass and body fat: 21 (3) years, 1.63 (0.05) m, 60 (7) kg, 27 (6)%, respectively]. VO2peak (l x min[-1]), defined as the highest value obtained during exercise to volitional fatigue, was determined using discontinuous protocols with treadmill grade or box mass incremented to increase exercise intensity. For RL VO2peak, a pneumatically driven shelf was used to lower a loaded box to the floor, and subjects then lifted the box, at a rate of 15 lifts x min(-1). VO2peak (l x min(-1) and ml x kg(-1) x min[-1]) and minute ventilation (VE, l x min[-1]) were determined using an on-line gas analysis system. A two-way repeated measures analysis of variance revealed significant gender effects, with men having higher values for VO2peak (l x min(-1) and ml x kg(-1) x min[-1]) and VE, but women having higher values of the ventilatory equivalent for oxygen (VE/VO2). There were also mode of exercise effects, with TR values being higher for VO2peak (l x min(-1) and ml x kg(-1) x min[-1]) and VE and an interaction effect for VO2peak (l x min(-1) and ml x kg(-1) x min[-1]) and VE/VO2. The women obtained a greater percentage (approximately 84%) of their TR VO2peak during RL than did the men (approximately 79%). There was a marginal tendency for women to decrease and men to increase their VE/VO2 when comparing TR with RL. The magnitude of the gender differences between the two exercise modalities appeared to be similar for heart rate, VE and R, but differed for VO2peak (l x min(-1) and ml x kg(-1) x min[-1]). Lifting to an absolute height (1.32 m for the RL protocol) may present a different physical challenge to men and women with respect to the degree of involvement of the muscle groups used during lifting and ventilation.

[Prevalence of Anophelines (Diptera: Culicidae) during sunset in areas of the Itaipu Hydroelectric plant in Guaíra county, state of Paraná, Brazil]. / Prevalência de anofelinos (Diptera: Culicidae) no crepúsculo vespertino em áreas da Usina Hidrelétrica de Itaipu, no município de Guaíra, estado do Paraná, Brasil.

Systematic collections of anophelines were conducted from November 1994 to August 1995 from 18:00 to 20:00 hr using Shannon traps and human-bait along the lake margin which forms the Itaipu Hydroelectric reservoir, State of Paraná, Brazil. Species prevalence was studied at 15 min intervals. Anopheles albitarsis sensu latu and An. galvaoi, were the most frequently collected mosquitoes. All Anopheles species populations peaked between 18:45 and 19:30 hr. The observations illustrate the existence of a haematophagic activity cycle during the early evening hours: exogenous stimulus (the beginning of sunset)-->Shannon trap (light attraction)-->human bait (haematophagy)-->rest and digestion-->exogenous stimulus-->Shannon trap or surrounding vegetation. The greater abundance of An. albitarsis collected in human-bait and Shannon trap suggests it may be a potential malaria vector in the region.

[Bionomical aspects of the Squamatoides triviattus (Diptera, Sarcophagidae) under laboratory conditions]. / Aspectos bionômicos de Squamatoides trivittatus (Diptera, Sarcophagidae) sob condições de laboratório.

Experiments with Squamatoides trivitattus were carried out in two different controlled temperatures (16 +/- 1 degree C/50-60% RH and 27 +/- 1 degree C/70-80% RH). The viability of larvae and pupae at 27 degrees C was 89.82% and 92.75% respectively. Larvae did not develop at 16 degrees C. Larval development lasted for 20 +/- 4 hr, 16 +/- 8 hr and 60 +/- 7 hr for the first, second and third instars, respectively, completing a total of 96 +/- 6 hr. The mean pupal period lasted for 15.7 +/- 1.6 days. In longevity tables for the adults, life-expectancy for 50% of the colony submitted to 16 degrees C was of 1.78 weeks for males and 2.42 for females. At 27 degrees C a life-expectancy of 1.15 weeks for males and 0.78 week for females was recorded. The average life-spans for males and females at 16 degrees C were 3.5 +/- 2.0 and 3.8 +/- 2.6 weeks, respectively, and 1.9 +/- 1.2 weeks for both sexes. At 27 degrees C, the longevity recorded was of 2.1 +/- 1.3 weeks for males and 1.7 +/- 1.1 week for females.

The effect of different proportions of males and females over the Chrysomya albiceps (Wiedemann 1819) (Diptera, calliphoridae) biotic potential and longevity under laboratory conditions.

Chrysomya albiceps specimens were derived from colonies kept under laboratory conditions. The oviposition period, total number of eggs-mass and the weight of the eggs-mass (average/female) presented significant differences between colonies regarding the sexual ratio of 1 male/1 female (situation 1), when compared to the other ratios (1 male/3 female, situation II), (1 male/5 female, situation III), (3 male/1 female, situation IV) and (5 male/1 female, situation V). It was ascertained that the increase in the proportion of females, resulted in higher weight and greater number of ovipositions and lengthening of the period of oviposition, leads to a decrease in their lifespan.

[Behavior of caliptrate Diptera in relation to oviposition substrates under laboratory conditions in Rio de Janeiro, RJ, Brazil]. / Comportamento de dípteros muscóides frente a substratos de oviposição, em laboratório, no Rio de Janeiro, RJ, Brasil.

How adult females of calyptrate Diptera recognize the appropriate breeding substrate is a matter of controversy. Among holometabolic insects, the feeding opportunities of immature stages are generally determined by the adult female choice of an oviposition site. The ovipositional and larvipositional substrate preference for the synanthropic flies (Chrysomya megacephala, C. putoria, Phaenicia cuprina: Calliphoridae; Atherigona orientalis, Synthesiomyia nudiseta: Muscidae; Ravinia belforti, Parasacophaga ruficornis, Peckia chrysostoma: Sarcophagidae) is presented in this work. The substrate used for testing were the following: bovine minced meat, fish (sardine), bovine liver, shrimp, squid, human faeces and banana. Bovine minced meat was the ovipositional and larvipositional substrate preferred by seven species. Human faces were preferred by R. belforti.

[Biology of Triatoma nitida Usinger, 1939 in laboratory conditions (Hemiptera: Reduviidae)]. / Biologia do Triatoma nitida Usinger, 1939 em laboratório (Hemiptera: Reduviidae).

Triatoma nitida is a wild species occurring in Mexico and Central America. In order to establish the length of its life cycle and transmission potential, the following parameters were observed: the incubation period, the interval between hatching, or moulting, and the first feeding; the number of blood meals and the time of development. The time-lapse before the bite, the length of feeding and the interval between the end of the blood meal and defecation, as well as the site of defecation were also analyzed. Average length of the egg incubation period was 18.2 days. Time interval between the food source offering and the bite was less than 4 min in 60% of the analyzed cases, except in the fifth instar, where only 38% of the insects began feeding in less than 5 min. The blood-sucking period was long and rising until the fifth instar, decreasing in adults, and ranging from 1 min to 2 and a half hours. Only 26% of the blood meals were followed by defecations within 20 min. The average length of the life cycle was 897.5 days.

Energy cost of wearing chemical protective clothing during progressive treadmill walking.

While chemical protective (CP) clothing is known to adversely affect physical performance, few data exist regarding the physiological response of wearing US military CP clothing during incremental, dynamic exercise. To quantify the effects of CP clothing on energy cost and to test the hypothesis that the mask contributes little to this effect, oxygen uptake (VO2) and ventilation (VE) were determined in 14 male soldiers who walked on a treadmill at 1.56 m.s-1 for 20 min each at 0, 5, and 10% grades in three clothing conditions: BDU (battledress uniform only), MASK (BDU + M-17 protective mask), and CP clothing (MASK + overgarment, gloves and boots). In BDU's, exercise intensities expressed as %VO2max were 29, 42, and 59% at the three grades, respectively. VO2 was significantly (p < 0.01) greater at all grades (range 13 to 18%) in CP clothing compared to BDU. However, no differences in VO2 were seen between BDU and MASK at any level of exercise. VE was significantly higher at the two highest grades in CP clothing compared to BDU but when expressed relative to VO2 (VE/VO2) was significantly lower at 0% and 5% grades but not at 10%. In the MASK condition, VE was significantly lower at the 10% grade and VE/VO2 was significantly lower at all grades compared to BDU. The results show that despite the mask induced hypoventilation, VO2 is unaffected at exercise intensities up to 60% of VO2max.(ABSTRACT TRUNCATED AT 250 WORDS)

Lethal effect of a bait for Rhodnius prolixus (Hemiptera: Reduviidae), the vector of Chagas' disease, containing hexachlorocyclohexane (HCH), under laboratory conditions.

The lethal effect of a bait containing an aqueous hexachlorocyclohexane (HCH) suspension at the concentration of 1g/l and maintained at room temperature was studied in the laboratory over a period of 12 weeks. The suspension was placed in a latex bag hanging inside a 1000-ml beaker tightly covered with nylon netting, and left there with no changes for 85 days. Sixteen groups of R. prolixus bugs, consisting on average of 30 specimens each, were successively exposed to the bait and observed at different intervals for one week each. The mortality rate was 100% for all groups, except for the 16th, whose mortality rate was 96.7%. As the groups succeeded one another, mortality started to occur more rapidly and was more marked at the 6- and 24-h intervals. Later tests respectively started at 6:00 a.m. and 6:00 p.m. showed that diurnal and nocturnal periodicity in the offer of food had no effect on mortality. First- and 2nd- instar nymphs and adults male were more sensitive and 5th- instar nymphs were more resistant to the active principle of the bait.

Lethality of triatomines (Hemiptera: Reduviidae), vectors of Chagas' disease, feeding on blood baits containing synthetic insecticides, under laboratory conditions.

A laboratory study was conducted to test the toxicity of synthetic insecticides added to defibrinated sheep blood kept at room temperature and offered as food to the following triatomine species: Triatoma infestans, Panstrongylus megistus, Triatoma vitticeps, Triatoma pseudomaculata, Triatoma brasiliensis and Rhodnius prolixus. The insecticides used, at a concentration of 1 g/l, were: HCH, DDT, Malathion and Trichlorfon, and the lethalithy observed at the end of a 7-day period varied according to the active principle of each. HCH was the most effective by the oral route, killing 100% of the insects, except P. megistus (95.7%) and T. pseudomaculata (94.1%). Trichlorfon killed the insects at rates ranging from 71.8% (T. vitticeps) to 98% (R. prolixus). Malathion was slightly less efficient, killing the insects at rates from 56.8% (T. vitticeps) to 97% (T. brasiliensis). DDT was the least effective, with a killing rate of 10% (T. vitticeps) to 75% (T. brasiliensis). Since the tests were performed at room temperature, we suggest that baits of this type should be tried for the control of triatomines in the field.

Physiological responses to prolonged treadmill walking with external loads.

Limited information is available regarding the physiological responses to prolonged load carriage. This study determined the energy cost of prolonged treadmill walking (fixed distance of 12 km) at speeds of 1.10 m.s-1, 1.35 m.s-1, and 1.60 m.s-1, unloaded (clothing mass 5.2 kg) and with external loads of 31.5 and 49.4 kg. Fifteen male subjects performed nine trials in random order over a 6-week period. Oxygen uptake (VO2) was determined at the end of the first 10 min and every 20 min thereafter. A 10-min rest period was allowed following each 50 min of walking. No changes occurred in VO2 over time in the unloaded condition at any speed. The 31.5 and 49.4 kg loads, however, produced significant increases (ranging from 10 to 18%) at the two fastest and at all three speeds, respectively, even at initial exercise intensities less than 30% VO2max. In addition, the 49.4 kg load elicited a significantly higher (P less than 0.05) VO2 than did the 31.5 kg load at all speeds. The measured values of metabolic cost were also compared to those predicted using the formula of Pandolf et al. In trials where VO2 increased significantly over time, predicted values underestimated the actual metabolic cost during the final minute by 10-16%. It is concluded that energy cost during prolonged load carriage is not constant but increases significantly over time even at low relative exercise intensities. It is further concluded that applying the prediction model which estimates energy expenditure from short-term load carriage efforts to prolonged load carriage can result in significant underestimations of the actual energy cost.

Effect of precocene II, ecdysone and juvenile Hormone on the glicogen concentration in pupae of Stomocys calcitram (Diptera muscidae)

Larvas de terceiro instar de Stomoxys calcitrans (L.) foram tratadas com precoceno II, ecdisona e hormônio juvenil. O desenvolvimento ocorreu até acontecer a pupaçäo, quando os níveis de glicogênio foram determinados. A administraçäo daquelas três substâncias interferiu na concentraçäo de glicogênio. O precoceno II causou uma diminuiçäo enquanto a ecdisona e o hormônio juvenil um aumento. A ecdisona administrada junto com o precoceno II reverteu o efeito do último, o que näo aconteceu quando o precoceno foi administrado junto com o hormônio juvenil. A ecdisona, administrada junto com o hormônio juvenil, causou reduçäo na concentraçäo do glicogênio

An analysis of aerobic capacity in a large United States population.

This study presents a description of aerobic capacity in a large US population comprised of 1,514 men and 375 women. Such influencing factors as age, training state, occupation, and body composition were evaluated. The population consisted of new recruits entering the US Army from civilian life as well as soliders in a variety of assignments and physical training programs. Age ranged from 17 to 55 yr. With the exception of one older group, aerobic capacity was determined as maximal O2 uptake measured directly by the Douglas bag technique during a standard discontinuous treadmill running procedure. New male and female recruits representing a young civilian population entered the service with maximal O2 uptake of 51 and 37 ml X kg body wt-1 X min-1, respectively, and thereafter increased 5% during initial basic training. The difference between genders, 30% on an absolute basis, was 14% when expressed as a function of fat-free weight. Aerobic capacity was less after occupational training and continued to decrease with age at an average yearly rate of 10%, or 0.5 ml X kg body wt-1 X min-1. Aerobic capacity varied with intensity of the occupational physical demand, except in groups with significant physical training programs. This first large US population study of aerobic capacity, using a direct treadmill procedure, demonstrates levels consistent with any previously reported population.

The effect of two years' training on aerobic power and muscle strength in male and female cadets.

During their first 2 years of training at the U.S. Military Academy, 11 male and 7 female cadets were studied on five occasions. VO2 max (1/min), lean body mass and body weight increased significantly in both groups. Percent body fat was significantly reduced only after the first summer of training and then returned to initial values. VO2 max (ml/kg.min) did not change in males during the study. However, females increased significantly after the initial 6 weeks of training (44.2 to 48.8 ml/kg.min). They remained at this level through the second summer of training. However, by the end of their second academic year, females' values dropped to 45.9 ml/kg.min. Maximal isometric strength measured 30-40% higher in males than in females. During the last year of training, arm and shoulder strength increased 10.2% in males, but was unchanged in females. Our results suggest that even extended military training did not enable females to significantly narrow the difference with male cadets in muscle strength and aerobic power.