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BACKGROUND: It has been reported that the concentration of Dermatophagoides sp. population, the main trigger of asthma in sensitized atopic subjects, is inversely related with altitude and probably directly with humidity and that this population are scarcely found over 1750 m above sea level. OBJECTIVE: We studied the presence of Dermatophagoides sp. in a Venezuelan community between 2040 and 2600 m above sea level, and also the IgE response to D. pteronnyssinus and D. farinae in atopic subjects living on that region. METHODS: The presence of Dermatophagoides sp. was determined by microscopic identification of mites in dust, obtained by brushing the mattresses surface in 93 randomly selected houses between 2040 and 2600 m above sea level. The indoor relative humidity was also measured. The specific IgE serum levels were studied in 65 subjects classified as asthmatics, allergic non-asthmatics and non-allergic. RESULTS: A mean concentration of 188 mites/g of room dust was determined in 82.4% of houses with an indoor relative humidity ranging from 89% and 92% independently of altitude. The density of Dermatophagoides sp. was sufficiently high to sensitize the atopic subjects, IgE levels were 6.8 PRU mean value for asthmatic, against 0.38 PRU in non-atopic. CONCLUSIONS: We conclude that: (a) Dermatophagoides sp. can be found up to 2600 m above sea level in a Venezuelan neotropical region where a high indoor relative humidity is characteristic of most dwellings; (b) sensitization by D. pteronyssinus and D. farinae were demonstrated in atopic subjects resident at that region.  相似文献   

3.
A new genus and two new species of fossil Fuziidae are described and illustrated: Parvifuzia gen. nov., P. marsa sp. nov. and P. brava sp. nov.. Both species were collected from the Middle Jurassic Jiulongshan, Formation of Daohugou, Inner Mongolia of China. In conjunction with Fuzia Vr(s)ansk(y),Liang et Ren, 2009, the present findings allow us to demonstrate that members of the family were morphologically diverse, with body length ranging from medium (17 mm) in Fuzia to small (9.7 mm) in the present genus. Wing venation of F. dadao is complicated, but simple in the present species, and apex of male's cerci are sharp and forceps-like in F. dadao, but strongly curved inward and round in the new genus.  相似文献   

4.
Mutations at the disconnected (disco) locus of Drosophila melanogaster disrupt neural cell patterning in the visual system, leading to the loss of many optic lobe neurons. Drosophila's presumptive circadian pacemaker neurons--the dorsal and ventral lateral neurons--are usually among the missing cells, and most disco flies are behaviorally arrhythmic. In this study, I show that ventral lateral neurons (LNvs) are occasionally present and provoke robust circadian rhythmicity in disco mutants. Of 357 individual disco flies four animals with robust circadian rhythmicity were found. All four retained LNvs together with terminals in the superior protocerebrum. Residual or bi-circadian rhythmicity was found in about 20% of all flies; the remaining flies were completely arrhythmic. One of the flies with residual rhythmicity and two of the arrhythmic flies also had some LNvs stained. However, these flies lacked the LNv fibers in the superior protocerebrum. The results suggest that the presence of single LNvs is sufficient to provoke robust circadian rhythmicity in locomotor activity if the LNv terminals reach the superior protocerebrum. The presence of residual or bi-circadian rhythmicity in 20% of the flies without LNvs indicates that also other cells contribute to the rhythmic control of locomotor activity.  相似文献   

5.
The prevalence of ruminant trypanosomosis and tsetse flies was investigated in Katsina-Ala Local Government Area--a sleeping sickness endemic area--between the valleys of River Benue, Katsina-Ala and Donga in Central Nigeria. Analysis of three hundred and twenty blood samples showed that among semi-nomadic animals, about one cattle (21.3%; 0.213, confidence interval C1 +/- 0.06) and two sheep (38.0%; 0.380, C1 +/- 0.10) out of five carried mature trypanosome infections. Significantly lower (P < 0.05) values (12.5%; 0.125, C1 +/- 0.08) were recorded among peri-domestic West African Cross Red Sokoto (WAD x RS) goats. Trypanosoma vivax was the most prevalent species encountered; it was diagnosed in 10.3% of the ruminant population and responsible for 42.8% of the infections in all animals. Corresponding figures for T. congolense were 5.9% and 24.6%, respectively. T. brucei infections were low in cattle (1.8%) and absent in goats. Males and young stock had lower infection but the difference was not significant (P > 0.05) except between the ages in cattle. Glossina tachinoides was the only tsetse species encountered and responded to acetone odour attractant in biconical traps.  相似文献   

6.
In this paper, we studied three species of prosimian primate (Propithecus diadema edwardsi, Eulemur fulvus rufus, and Eulemur rubriventer) from June-July 1995 at the Ranomafana National Park to answer three questions: 1) how they handle and process seeds, 2) how the physical properties of seeds influence seed handling and seed fate, and 3) whether handling and processing patterns influence seed dispersal. Seeds from five plant species were collected from feces and examined for external damage (punctures and scrapes), weighed, measured, and checked daily for germination. P. d. edwardsi masticated seeds into two or more pieces while feeding. Seed fragments were either dropped under the parent tree or chewed and swallowed; seeds never emerged as recognizable units in feces. In contrast, both Eulemur species either dropped or swallowed seeds whole while feeding. E. rubriventer passed seeds that were longer, wider, and heavier than seeds passed by E.f. rufus. Although seeds emerged as separate units when passed by both Eulemur species, 65 Protorhus sp. seeds were scraped and/or punctured prior to being swallowed. Based on physical property tests, Protorhus seeds were more susceptible to mastication than undamaged seeds from Eugenia sp., Cissus sp., and Chrysophyllum madagascariensis. H. madagascariensis seeds also were undamaged but had physical properties comparable to Protorhus and may avoid being masticated due to their small size (2-3 mm). All damaged seeds were moldy or rotten within 6 days, and only 15% of the undamaged seeds passed by E. rubriventer germinated. None of the seeds passed by E.f. rufus germinated. Eulemur species also rested in the same tree after feeding and defecated prior to a new feeding bout or before moving, so seeds were most likely to be dispersed under the parent tree. Consequently, we concluded that these primate species do not appear to serve as effective seed dispersers for these plant species at this time of year.  相似文献   

7.
Meiotically driven sex chromosomes can quickly spread to fixation and cause population extinction unless balanced by selection or suppressed by genetic modifiers. We report results of genetic analyses that demonstrate that extreme female-biased sex ratios in two sister species of stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei, are due to a meiotic drive element on the X chromosome (Xd). Relatively high frequencies of Xd in C. dalmanni and C. whitei (13-17% and 29%, respectively) cause female-biased sex ratios in natural populations of both species. Sex ratio distortion is associated with spermatid degeneration in male carriers of Xd. Variation in sex ratios is caused by Y-linked and autosomal factors that decrease the intensity of meiotic drive. Y-linked polymorphism for resistance to drive exists in C. dalmanni in which a resistant Y chromosome reduces the intensity and reverses the direction of meiotic drive. When paired with Xd, modifying Y chromosomes (Ym) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny. The absence of sex ratio distortion in closely related monomorphic outgroup species suggests that this meiotic drive system may predate the origin of C. whitei and C. dalmanni. We discuss factors likely to be involved in the persistence of these sex-linked polymorphisms and consider the impact of Xd on the operational sex ratio and the intensity of sexual selection in these extremely sexually dimorphic flies.  相似文献   

8.
Mating speed of flies which have been aged either in the light, in the dark or in a light-and-dark cycle was measured using two strains, Rochester (R) and Salvador (S), of Drosophila mercatorum. A significant difference in mating tendency depending on the condition of pretreatment was found between R and S strains, while both strains showed a similar pattern of the diurnal rhythm in the light-and-dark cycle. Compared under the same conditions, S flies usually showed a higher mating speed than R flies. Mating speed seems to be affected by at least two different genetic systems. One of them is the genetic system determining absolute speed of mating. Another is the genetic system determining sensitivity to the environmental conditions. There may be considerable differentiation in both systems between R and S strains.  相似文献   

9.
The Sarcophagidae (Flesh) of Saudi Arabia are reviewed based on collections of adult flies. Ten species of sarcophagid flies were recorded of which five are considered to be new record in Saudi Arabia. Checklist and information are given for each species concerning its geographical distributions and other observations.  相似文献   

10.
During 1994, 129 specimens of chub (Leuciscus cephalus L.) from two localities, polluted--Bolelouc, 80th river kilometer, near the city of Olomouc, and unpolluted--Brodské, 225th river kilometer, near the Lanzhot on the Morava river, were examined for metazoan parasites. Altogether 38 metazoan parasite species including helminths, leeches and glochidia belonging to 14 genera were found, 34 in the case of unpolluted locality (Brodské) and 28 in the polluted one (Bolelouc). In both localities, 24 parasite species (Dactylogyrus folkmanovae, D. naviculoides, D. prostae, D. vistulae, D. vranoviensis, Gyrodactylus carassii, G. gasterostei, G. gracilihamatus, G. scardiniensis, G. vimbi, Gyrodactylus sp., Paradiplozoon ergensi, P. homoion, P. megan, Paradiplozoon sp., Caryophyllaeus brachycollis, Diplostomum spathaceum--larval stage, Philometra abdominalis, Acanthocephalus anguillae, Pomphorhynchus laevis and Glochidium sp.) were found, 10 (D. crucifer, D. nanoides, G. hemibarbi, G. lamberti, G. leucisci, G. lomi, P. rutili, C. fennica, A. imitans, S. bramae) were identified solely in the unpolluted locality Brodské and 4 (D. fallax, G. laevis, P. ovata, G. kearni) parasite species were found only in the polluted locality Bolelouc. Differences in parasite species richness, the level of dominance, the structure of core and in satellite species were observed. Current methods of statistical evaluation were used.  相似文献   

11.
The presence of Leishmania donovani DNA in sand flies caught in Indian kala-azar patients' dwellings during the epidemic of 1990-1992 was studied using the polymerase chain reaction (PCR). Amplification of miniexon-derived RNA genes and gpG3 mRNA was achieved in single Phlebotomus argentipes, P. papatasi, and Sergentomyia babu flies. The data suggest the possible involvement of multiple sandfly species in kala-azar transmission.  相似文献   

12.
Arthrobacter spp. are very widely distributed in the environment (e.g., soil) but have not been described as causing disease in humans. Over a 6-year period, two reference laboratories isolated or received 11 strains which were eventually identified as belonging to the genus Arthrobacter. These strains had been initially identified as Centers for Disease Control and Prevention coryneform group B-1 and B-3 bacteria (whitishgrayish colonies of 2 mm or greater in diameter after 24 h of incubation, respiratory metabolism, absent or weak acid production from sugars, and hydrolysis of gelatin). However, chemotaxonomic investigations revealed lysine as the diamino acid of the cell wall and the presence of branched cellular fatty acids (with anteiso-pentadecanoic acid predominating) which was compatible with an assignment of the 11 isolates to the genus Arthrobacter only. Peptidoglycan and 16S rRNA gene sequence analyses demonstrated that three of the strains studied were representatives of a new Arthrobacter species for which the name Arthrobacter cumminsii sp. nov. is proposed and that one other strain represented a second new Arthrobacter species for which the name Arthrobacter woluwensis sp. nov. is proposed. This report is the first on the isolation of Arthrobacter spp. from clinical specimens.  相似文献   

13.
We measured metabolic rates of adult male Drosophila melanogaster allowed to evolve in the laboratory at 18 and 25 degrees C and compared these with measurements of metabolic rates of flies collected along a latitudinal gradient in Australia. Metabolic rates of flies that had evolved in the laboratory at low temperature were 5-7% higher than those of flies allowed to evolve at high temperature. Metabolic rates of field collected increased with latitude when measured at 18 degrees C but not at higher temperature (25 degrees C) and were about 9% greater in high latitude (approximately 41'00) flies than low latitude (16'53) flies. Metabolic rate was strongly influenced by measurement temperature; estimated Q10s ranged from 1.79 to 2.5 for measurements made at 18 and 25 degrees C. Metabolic rate scaled isometrically with body mass; the estimated slope of a ln-ln regression of metabolic rate and body mass was 1.03 +/- 0.1. We used our measures of metabolic rate and activity to estimate the minimum cost of transport (MCOT) while walking. The estimates of MCOT have high standard errors (lab, 34.30 +/- 14.2 ml O2/g/km; and field, 38.0 +/- 17.0 ml O2/g/km); however, they differ by only 3-9% from predicted values based on allometric relationships reported in the literature.  相似文献   

14.
Sequence relationships and functional aspects were analysed in the P element homologues of Drosophila subobscura (Ds) and D. guanche (Dg). In both species, the P homologues are clustered at a single genomic position. They lack the characteristic terminal structures of actively transposing P elements, but they have the coding capacity for a 66-kDa 'repressor-like' protein. Two different types of cluster units (G-type and A-type) can be distinguished. The A-type unit, which is present in multiple copies, is transcribed in adult flies. In contrast, the G-type unit has a much lower copy number and is apparently not expressed. In Dg, the isolated G-type sequence carries a 420-bp insertion in the promoter region, which is probably responsible for inactivation. Sequence comparisons of different cluster units show that differentiation of the two types precedes the lineage split of these species. Substitution rates of the deduced proteins reveal two distinct subregions: high variability at the N terminus and strong sequence conservation in the rest of the protein. The variable region contains motifs characteristic of DNA-binding proteins. Adaptive diversification of the cluster units towards specific binding properties might be a plausible explanation for variability in the N-termini. Both unit types have lost the weak promoter region characteristic of P transposons. In the A-type unit, a new promoter has been formed which is apparently composed of parts of insertion sequences derived from two different mobile elements.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
The polymerase chain reaction was used to characterize the trypanosomes infecting Glossina morsitans submorsitans and G. tachinoides in the game ranch of Nazinga, Burkina Faso, situated near an agropastoral zone. Dissection of 435 tsetse flies, and PCR analysis of 166 infected flies were conducted to assess the epidemiological situation. Trypanosomes of the Nannomonas subgenus were the most abundant in the two tsetse species (80.4% and 73.7% of identified infections in G. m. submorsitans and G. tachinoides respectively). T. vivax and T. brucei infection rates were comparable between the two tsetse species. Mature infection pattern identified by PCR differed from overall infections, mainly because T. simiae infections did not mature, whereas T. vivax represented the predominant taxon. Parasitological and PCR results showed some discrepancies; possibly some typical Duttonella strains could not be recognized by the sets of primers used. The technologies used in this work helped to determine the high trypanosomosis risk in this area.  相似文献   

16.
Male-male courtship behavior was recently reported to be induced in large populations of Drosophila (e.g., 600-1500 flies) by ectopic expression of the white (w) gene. Little is known about the basis of this behavior; in male-female courtship, sensory cues are believed to play an important role. Previous data are consistent with the possibility that misexpression of w causes abnormal reception or processing of sensory information. We show here that w-induced male-male courtship occurs in isolated pairs of flies. Thus the behavior does not depend on sensory cues found only among large populations of flies, or on cues produced only by a small subset of such populations. This finding enabled quantitative analysis of mechanisms that underlie the behavior. Specifically, male-male courtship does not depend on the reception of olfactory information, nor on the reception or generation of auditory cues, as determined by surgical ablation of antennae, maxillary palps, or wings. Although the rapid onset of the behavior following w induction suggested that its basis could lie in a modulation of sensory physiology, we found visual, olfactory, and gustatory function to be normal in physiological or behavioral tests. The only sensory deprivation to produce an effect on male-male courtship was testing under dim red light; the percentage of flies courting another male was reduced to one-fourth of control values. A striking age dependence of the behavior is also documented: courtship between paired male mini-w+ flies was not observed in tests of very young (1-day-old) flies, but occurs at high levels between the ages of 1 and 4 weeks.  相似文献   

17.
The principal objective of this study was to test the hypothesis that acclimatization to moderate altitude (2,500 m) plus training at low altitude (1,250 m), "living high-training low," improves sea-level performance in well-trained runners more than an equivalent sea-level or altitude control. Thirty-nine competitive runners (27 men, 12 women) completed 1) a 2-wk lead-in phase, followed by 2) 4 wk of supervised training at sea level; and 3) 4 wk of field training camp randomized to three groups: "high-low" (n = 13), living at moderate altitude (2,500 m) and training at low altitude (1,250 m); "high-high" (n = 13), living and training at moderate altitude (2,500 m); or "low-low" (n = 13), living and training in a mountain environment at sea level (150 m). A 5,000-m time trial was the primary measure of performance; laboratory outcomes included maximal O2 uptake (VO2 max), anaerobic capacity (accumulated O2 deficit), maximal steady state (MSS; ventilatory threshold), running economy, velocity at VO2 max, and blood compartment volumes. Both altitude groups significantly increased VO2 max (5%) in direct proportion to an increase in red cell mass volume (9%; r = 0.37, P < 0.05), neither of which changed in the control. Five-kilometer time was improved by the field training camp only in the high-low group (13.4 +/- 10 s), in direct proportion to the increase in VO2 max (r = 0.65, P < 0.01). Velocity at VO2 max and MSS also improved only in the high-low group. Four weeks of living high-training low improves sea-level running performance in trained runners due to altitude acclimatization (increase in red cell mass volume and VO2 max) and maintenance of sea-level training velocities, most likely accounting for the increase in velocity at VO2 max and MSS.  相似文献   

18.
It has been shown that fluctuation of human heartbeat intervals [heart rate variability (HRV)] reflects variations in cardiac autonomic nervous system activity. The present study was designed to investigate whether the acute exposure to moderate levels of simulated altitude and the resultant hypoxia could modify HRV during exercise. Seven healthy men completed one resting measurement in the upright sitting position and two submaximal steady-state cycle ergometer exercises at intensities equivalent to 25 and 50% of their estimated maximal work rate. Experiments were conducted in random order at altitude equivalents of 500, 1,500, 2,500, and 3,500 m within 2 h of exposure to that altitude. Beat-to-beat HRV was measured continuously during the tests. HRV data were analyzed by "coarse-graining spectral analysis" (Y. Yamamoto and R.L. Hughson, Physica 68D: 250-264, 1993) to break down their total power (PT) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low (0.0- to 0.15-Hz; PL)- and high (> 0.15-Hz; PH)-frequency components, and the indicators of relative sympathetic (SNS) and parasympathetic (PNS) nervous system activities were calculated by PL/PH and PH/PT, respectively. The fractal component was used to calculate the spectral exponent (beta) to evaluate the overall "irregularity" of HRV. The effects of exercise intensity (increase in heart rate, SNS indicator, and beta and decrease in PNS indicator) were significant (P < 0.05) at all altitude levels. The altitude effects (increase in heart rate and SNS indicator and decrease in PNS indicator) were found only during exercise at 3,500 m (P < 0.05). There was no significant effect of altitude on beta (P > 0.05). These data indicate that acute effects of altitude exposure on HRV were found 1) during exercise at moderate altitude (> 2,500 m) and 2) mainly for the harmonic components of HRV.  相似文献   

19.
Migration of first-stage larvae (L1) from faeces to soil is a crucial stage in the life-history of protostrongylids transmitted via land snails. Migration of Muellerius cf. capillaris and a Cystocaulus sp. L1 from fresh Nubian ibex (Capra ibex nubiana) faeces (48-50% water content, W.C.) to substrate soils (at 100% r.h., 26 degrees C) was measured experimentally using dry (3 +/- 1% W.C.), wet (31 +/- 0.43% W.C.) and flooded (48.4 +/- 2.45% W.C.) soils. The highest migration rates (90.4 +/- 1.6% migration) in both species occurred on flooded soils when the faecal pellet W.C. reached 90%. The next highest migration rates (43.2 +/- 3.6% migration, at 60% faecal W.C.) were on the wet soils and no migration occurred on dry soil or dry-substrate papers. Migration rates did not differ significantly (P > 0.05) between species. Active Theba pisana were not infected by M. cf. capillaris L1 on dry infested soils, but were infected following rehydration of the same soils. By day 10, L1 of M. cf. capillaris demonstrated lower survival rates in water and in 97% and 76% r.h. (74.5%, 15.2% and 1.9%, respectively) than the Cystocaulus sp. (97.5%, 43.8%, 43.3%) and Protostrongylus sp. (97.9%, 43.2%, 23.8%, P < 0.05). All three nematodes had a remarkably high survival rate (> 99% overall survival, by day 10) when exposed directly to 0% r.h. at 23 degrees C. Results demonstrate the ability of L1 to survive extreme desiccation through anhydrobiosis. Migration of L1 from faeces to soil can take place only during rains which coincide with peak activity of land snails in desert habitat.  相似文献   

20.
Short or long-term athletic training has been associated with left ventricular (LV) morphological adaptations, including increases in wall thickness, cavity dimension and estimated LV mass. A limitation of previous studies assessing the 'athlete heart' was that exercise training was performed at sea level. Since the 1968 Olympic summer games a popular method of maximizing athletic performance has been to use altitude training (AT) as a means of improving sea level performance. However, the effects of short term AT and taper training on LV morphology have not been well studied. Based on this limitation, the effects of three weeks of intense AT (1848 m) or low level control training (CT) (1050 m) followed by two weeks of taper training were investigated in 15 elite swimmers between 16 and 21 years of age. Short term AT or CT training followed by two weeks of taper training was not associated with alterations in LV diastolic cavity dimension (AT pre 53.3 +/- 2.8 mm versus post 52.6 +/- 4.3 mm; CT pre 52.9 +/- 3.7 mm versus post 51.2 +/- 4.0 mm), ventricular septal wall thickness (AT pre 9.6 +/- 1.0 mm versus post 9.4 +/- 1.1 mm; CT pre 8.4 +/- 1.2 mm versus post 8.6 +/- 1.1 mm), estimated LV mass (AT pre 186.4 +/- 45.8 g versus post 190.0 +/- 48.2 g; CT pre 159.1 +/- 35.8 g versus post 160.1 +/- 40.8 g) or fractional shortening (AT pre 36.8 +/- 3.5% versus post 34.8 +/- 2.7%; CT pre 32.6 +/- 5.0% versus post 32.8 +/- 4.7%). However, a main time effect, independent of training intervention, was observed for posterior wall thickness (pre 8.7 +/- 1.4 mm versus post 9.3 +/- 1.1 mm, P < 0.05). Therefore, with the exception of posterior wall thickness, short term AT followed by two weeks of taper training appears not to be associated with alterations in LV morphology or systolic function.  相似文献   

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