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1.
Unfed adult Amblyomma americanum were exposed to the entomopathogenic fungus Beauveria bassiana and placed in the field. Ticks exposed to the fungus experienced higher mortality than those in the control group (P = 0.001). It is recommended that for inclusion in a tick management program, the fungus be applied in the late evening during the months March through June as this is when ticks are most active and conditions suitable for fungal activity occur.  相似文献   

2.
The life cycle of Amblyomma auricularium (Conil) is reported for the first time, using rabbits as experimental host. Developmental periods of free-living stages were observed in an incubator at 27 ± 1°C, 80 ± 10% RH and 24 h darkness. The complete life cycle, including pre-feeding periods for each parasitic stage, ranged from 97 to 162 days. The overall sex ratio was 1.16:1 (M:F). Feeding and premolt periods, molting success, and engorgement weight of nymphs were statistically different between males and females (P < 0.01), but because their ranges overlapped, they cannot be used to predict the sex with accuracy. The potential role of rabbits as experimental hosts for rearing A. auricularium in the laboratory is discussed.  相似文献   

3.
Three Australian native animal species yielded 60 samples composed of three indigenous ticks. Hosts included twelve koalas, two echidnas and one wombat from Victoria, and ticks were of the species Ixodes tasmani (n = 42), Bothriocroton concolor (n = 8) and B. auruginans (n = 10), respectively. PCR screening and sequencing detected a species of Coxiella, sharing closest sequence identity to C. burnetii (>98%), in all B. auruginans, as well as a species of Rickettsia, matching closest to R. massiliae, in 70% of the same samples. A genotype sharing closest similarity to Rickettsia bellii (>99%) was identified in three female B. concolor collected from one of the echidnas. Three samples of I. tasmani, taken from three koalas, yielded different genotypes of Rickettsiella. These results represent the first detection of the three genera in each tick species and identify a high level of previously undetected bacterial diversity in Australian ticks.  相似文献   

4.
Conidia of the entomopathogenic fungus, Metarhizium anisopliae, in oil/water formulation (1 × 108 conidia/ml) were sprayed at 3 weekly intervals on Rhipicephalus evertsi evertsi and Rhipicephalus (Boophilus) decoloratus ticks while feeding on Afrikana bulls grazing in paddocks for a period of 1 year. The fungus reduced the on-host tick populations by 83% 3 month after commencement of the experiment. The formulation by itself had only minimal effect on the tick population. Tick populations and fungal efficacy were highest at the peaks of rainfall and relative humidity or soon thereafter. Fed and unfed adult R. e. evertsi and R. (B.) decoloratus collected at the end of the experiment from the fungus-sprayed and from the control cattle and incubated in the laboratory exhibited a mortality of 93% in oil formulated conidia and 14% in oil control. The corresponding mortality in R. (B.) decoloratus was 100% in fungus and 11% in oil control. Ticks on the fungus-sprayed groups had significantly higher mortality (P < 0.05) than on the control groups. Furthermore, no significant difference (P < 0.05) was observed in fungus-induced mortality between the two tick species. Mortalities induced by Triton X-100 (0.05%), sunflower oil (20%) and water alone were low, suggesting that they were non-toxic to ticks at the concentrations used and no significant difference was observed among them. No physical or behavioral abnormalities were observed in the fungus-sprayed cattle at any time during the course of the experiment. All groups of cattle gained weights during the experimental period.  相似文献   

5.
The viability of a formulation of Duddingtonia flagrans was assessed in the control of parasite gastrointestinal nematodes of cattle. Two groups (A and B) of eight crossbred Holstein × Zebu cattle, approximately one year old, were placed in Brachiaria decumbens pasture. Each animal in group B (treated) received orally 20 g sodium alginate pellets containing mycelial mass of the D. flagrans fungus, while the animals in the group A (control) received pellets without fungus for seven months, starting in March 2005. The egg per gram of feces counting the gastrointestinal nematodes showed a difference (P < 0.05) in the treated group in June, July and August, with reductions of 58% (June), 47% (July) and 51% (August) compared to the control group. The infective larvae recovered in the pastures collected up to 20 cm from distance of the fecal dung in group B differed (P < 0.01) from the larvae recovered in group A. At the end of the experimental period, the animals in group B presented a greater weight gain (P < 0.01) compared to the untreated group (A). The treatment of cattle with pellets containing the D. flagrans nematophagous fungus, at the dose and duration used was effective in controlling the infective larvae of gastrointestinal nematodes of cattle.  相似文献   

6.
Logistic regression analysis was used to analyse sex allocation in a population of the leaf-cutting ant Acromyrmex balzani occurring in a pasture in southern Brazil. The field sample consisted of 151 fungus-garden chambers (18 queenright and 133 queenless), belonging to 50 nests with three vertically stacked chambers per nest on average. Taking nest chamber as the unit of analysis, seven predictor variables were considered: sampling date, chamber depth, chamber volume, weight of fungus garden, presence of a queen, number of large workers, and number of small to medium workers. The population-level numerical proportion of females was 0.548 and the inferred proportional energetic investment in females 0.672. The former was not significantly different from 0.5 (P=0.168), but the latter was (P=0.0003). The proportional investment in females per fungus garden increased with the number of large workers present (P=0.0002) and decreased with the dry weight of the fungus garden (P=0.012). This implies that resource acquisition through foraging is likely to be a major proximate determinant of sex allocation. The negative correlation between female bias and fungus garden weight might be due to developing adult females requiring more food than males, but this hypothesis could not be confirmed by direct statistical evidence.  相似文献   

7.
Lu L  Sheng H  Li H  Gan W  Liu C  Zhu J  Loos RJ  Lin X 《Human genetics》2012,131(3):505-512
Recent studies have identified common variants in or near GC, CYP2R1 and NADSYN1/DHCR7 to be associated with 25-hydroxyvitamin D [25(OH)D] levels in European populations. We aimed to examine whether these variants also influence 25(OH)D levels in Chinese. Seven common variants were successfully genotyped and tested for associations with plasma 25(OH)D levels in a population-based cohort of 3,210 Chinese Hans from Beijing and Shanghai. Six common variants at GC (rs4588, rs7041, rs2282679 and rs1155563) and NADSYN1/DHCR7 (rs3829251 and rs1790349) loci were all significantly associated with lower plasma 25(OH)D levels (−0.036 ≤ β ≤ −0.076 per risk-allele, P ≤ 5.7 × 10−5), while CYP2R1-rs2060793 showed a trend toward association with 25(OH)D levels in the Shanghai subpopulation (P = 0.08), but not in the Beijing subpopulation (P = 0.82). Haplotype-based association analyses of the four GC variants showed that only the haplotype that contained all risk-alleles (TACC) was significantly associated with lower plasma 25(OH)D levels (β = −0.085, P = 2.3 × 10−9), while the haplotype containing the risk-alleles of rs4588 and rs2282679 (TATC) was marginally associated with lower 25(OH)D levels (β = −0.054, P = 0.0562) when compared with GCTA haplotype carrying the four protective alleles. Most notably, conditional analyses showed that only GC-rs4588 and GC-rs2282679 (r 2 = 0.97) remained significantly associated with 25(OH)D concentrations (P ≤ 1.9 × 10−5) after adjusting for the other two SNPs in GC. In conclusion, GC and NADSYN1/DHCR7 loci individually and collectively contribute to variation in plasma vitamin D levels in Chinese Hans.  相似文献   

8.
The present study was done to determine the modulation effect(s) of polymorphisms of XRCC1, GSTM1, and GSTT1 on concentration of serum testosterone in females exposed to natural sour gas. Also we examine whether chronic exposure to natural gas containing sulfur compounds act as natural selection force on XRCC1 polymorphisms. The present study was performed on 68 healthy unrelated female students living in polluted areas of MIS. Also for investigating the effect of natural selection on XRCC1 polymorphism, a study was performed on two groups of healthy individuals of MIS citizens. The first and second groups including 94 (age range 30–85 years) and 187 individuals (age range 5–20 years), respectively. First and second groups were born and were not born in contaminated areas of the MIS, respectively. There was no significant difference between genotypes of XRCC1 for concentration of serum testosterone. Although GSTT1-null genotype had higher level of serum testosterone in comparison with the present genotype (t = 2.392, df = 66, P = 0.023), a borderline difference between genotypes of GSTM1 for serum testosterone was observed (t = 1.928, df = 66, P = 0.058). Analysis of variance revealed significant difference between combination genotypes of GSTM1 and GSTT1 for serum testosterone (F = 4.167; df = 3, 64; P = 0.009). The Duncan post hoc test indicated that the combination genotype of “present GSTM1/null GSTT1” had significant higher level of testosterone. There is no evidence that XRCC1 polymorphisms have advantage/disadvantage when population exposed to natural sour gas. The polymorphisms of GSTM1 and GSTT1 modulate serum testosterone concentration in young females exposed to natural sour gas.  相似文献   

9.
Two extracellular chitinases were purified from Paecilomyces variotii DG-3, a chitinase producer and a nematode egg-parasitic fungus, to homogeneity by DEAE Sephadex A-50 and Sephadex G-100 chromatography. The purified enzymes were a monomer with an apparent molecular mass of 32 kDa (Chi32) and 46 kDa (Chi46), respectively, and showed chitinase activity bands with 0.01% glycol chitin as a substrate after SDS-PAGE. The first 20 and 15 N-terminal amino acid sequences of Chi32 and Chi46 were determined to be Asp-Pro-Typ-Gln-Thr-Asn-Val-Val-Tyr-Thr-Gly-Gln-Asp-Phe-Val-Ser-Pro-Asp-Leu-Phe and Asp-Ala-X-X-Tyr-Arg-Ser-Val-Ala-Tyr-Phe-Val-Asn-Trp-Ala, respectively. Optimal temperature and pH of the Chi32 and Chi46 were found to be both 60°C, and 2.5 and 3.0, respectively. Chi32 was almost inhibited by metal ions Ag+ and Hg2+ while Chi46 by Hg2+ and Pb2+ at a 10 mM concentration but both enzymes were enhanced by 1 mM concentration of Co2+. On analyzing the hydrolyzates of chitin oligomers [(GlcNAc) n , n = 2–6)], it was considered that Chi32 degraded chitin oligomers as an exo-type chitinase while Chi46 as an endo-type chitinase.  相似文献   

10.
Field trials were conducted to evaluate the efficacy of wheat bran bait formulations of Paranosema locustae and Metarhizium anisopliae for controlling grasshoppers in southeast Niger. Treatments consisted of wheat bran baits mixed with M. anisopliae, P. locustae + M. anisopliae or with P. locustae spores and P. locustae + sugar. Oedaleus senegalensis, Pyrgomorpha cognata and Acrotylus blondeli were the predominant species at the time of application representing ca. 94% of the total population. Bran application was done when O. senegalensis (ca. 75% of the population) was at its early developmental stages, with first, second and third instars accounting for 64–85%. Grasshopper population reduction, P. locustae prevalence and level of infections in the predominant species were monitored. Manual application of P. locustae and M. anisopliae formulated in wheat bran has proven to induce consistent pathogen infection in grasshopper populations. Population density over the three weeks monitoring, typically decreased by 44.7 ± 6.9%, 52.8 ± 8.4%, 73.7 ± 5.5% and 89.1 ± 1.8% in P. locustae, P. locustae + sugar, M. anisopliae and P. locustae + M. anisopliae treated plots respectively. Paranosema locustae prevalence in surviving adult grasshoppers at 28 after application was 48.1 ± 2.3%, 28.9 ± 4.8% and 27.4 ± 3.7%, with infection level of 6.2 ± 0.8 × 106, 2.3 ± 0.3 × 104 and 2.1 ± 0.3 × 103 spores mg−1 host weight in O. senegalensis, A blondeli and P. cognate respectively. Other species that each accounted for <2% of the community, namely Aiolopus thalassinus, A. simulatrix, Acorypha glaucopsis, Acrotylus patruelis, Anacridium melanorhodon, Diabolocatantops axillaris, Kraussaria angulifera and Schistocerca gregaria were found to show sign of infection. The results from this study suggest that wheat bran application of M. anisopliae and P. locustae alone or in combination, targeting early instars grasshopper could be a valuable option in grasshopper control programs.  相似文献   

11.
Despite the efficacy of antibiotics as well as bacteriophages in treatment of bacterial infections, their role in treatment of biofilm associated infections is still under consideration especially in case of older biofilms. Here, efficacy of bacteriophage alone or in combination with amoxicillin, for eradication of biofilm of Klebsiella pneumoniae B5055 has been assessed. Planktonic cells as well as biofilm of K. pneumoniae B5055 grown in 96-well microtiter plates were exposed to bacteriophage and amoxicillin at various Multiplicity of Infections (MoIs) as well as at three different antibiotic concentrations (512, 256 and 128 μg/ml), respectively. After exposure to 256 μg/ml (MIC) of amoxicillin, bacterial load of planktonic culture as well as 1-day-old biofilm was reduced by a log factor of 4.1 ± 0.31 (P = 0.008) and 1.24 ± 0.27 (P < 0.05), respectively but reduction in the bacterial load of mature biofilm (8-day-old) was insignificant (P = 0.23). When 8-day-old biofilm was exposed to higher antibiotic concentration (512 μg/ml) or phage alone (MoI = 0.01) a log reduction of 2.97 ± 0.11 (P = 0.182) and 3.51 ± 0.19 (P = 0.073), respectively was observed. While on exposing to a combination of both the amoxicillin and phage, a significant reduction (P < 0.01) in bacterial load of the biofilm was seen. Hence, when antibiotic was used in combination with specific bacteriophage a greater destruction of the biofilm structure suggested that the phages could be used successfully along with antibiotic therapy. An added advantage of the combination therapy would be its ability to check formation of resistant mutants that otherwise develop easily upon using phage or antibiotic alone.  相似文献   

12.
An investigation of the risk of human tick infestation, together with the prevalence of Borrelia burgdorferi s.l. infection, was conducted in a sylvatic habitat in western Germany to provide data needed for future risk-benefit evaluations of acaricides used for clothing impregnation. Additionally, data were collected on behavioural changes in Borrelia burgdorferi s.l.-infected adult female I. ricinus ticks and the possible impact of such changes on host-finding efficacy. The risk of I. ricinus-infestation was determined by collecting from the protective clothing of volunteers and by dragging in known tick-infested sites in the Kühkopf Mountain area, Koblenz, Germany, from June through October 2006. The overall tick infestation rate per person per hour was 7.4 ± 5.5, with the following sex- and stage-specific differences: males 0.32 ± 0.37, females 1.1 ± 1.2, nymphs 3.6 ± 4.4, larvae 2.4 ± 3.5. Concurrent dragging revealed an average 19.4 ± 16.2 times higher infestation rate as well as a markedly lower infection rate with borreliae in adult I. ricinus ticks when compared to ticks collected from exposed human volunteers. Although the difference in infection rates was statistically significant (P < 0.023) only in adult female ticks, our data indicate that B. burgdorferi s.l. infection may increase host-finding efficacy in adult I. ricinus. The overall exposure risk was 1.0 B. burgdorferi s.l.-infected ticks per person per hour of exposure, or 0.25 ticks per 100 m walking distance in the study area.  相似文献   

13.
Gammarus lacustris and Hyalella azteca (hereafter G. lacustris and H. azteca, respectively) are important components of secondary production in wetlands and shallow lakes of the upper Midwest, USA. Within the past 50 years, amphipod densities have decreased while occurrences of fish and intensity of agricultural land use have increased markedly across this landscape. We investigated influences of fish, sedimentation, and submerged aquatic vegetation (SAV) on densities of G. lacustris and H. azteca in semipermanent and permanent wetlands and shallow lakes (n = 283) throughout seven eco-physiographic regions of Iowa, Minnesota, and North Dakota during 2004–2005. G. lacustris and H. azteca densities were positively correlated with densities of SAV (P < 0.001 and P < 0.001, respectively). Both species were negatively correlated with densities of large fish (non-Cyprinidae; P = 0.01 and P = 0.013, respectively) and with high densities of fathead minnows (Pimephales promelas; P < 0.001 and P = 0.033, respectively). H. azteca densities also were negatively correlated with densities of small fish (e.g., other minnows [Cyprinidae] and sticklebacks [Gasterosteidae]; P = 0.048) and common carp (Cyprinus spp.; P = 0.022). G. lacustris densities were negatively correlated with high levels of suspended solids (an index for sedimentation; P < 0.001). H. azteca densities were positively correlated with the width of upland-vegetation buffers (P = 0.004). Our results indicate that sedimentation and fish reduce amphipod densities and may contribute to the current low densities of amphipods in the upper Midwest. Thus, removing/excluding fish, and providing a thick buffer of upland vegetation around wetlands may help restore amphipod densities and wetland and water quality within this landscape.  相似文献   

14.
15.
The consortium of Bacillus cereus (DQ002384), Serratia marcescens (AY927692) and Serratia marcescens (DQ002385) were used for pentachlorophenol (PCP) degradation. The consortia showed better overall removal efficiencies than single strains by utilization of PCP as a carbon and energy source confirmed by pH dependent dye indicator bromocresol purple (BCP) in mineral salt media (MSM). Mixed culture was found to degrade up to 93% of PCP (300 mg/l) as compared to single strains (62.75–90.33%), at optimized conditions (30 ± 1°C, pH 7 ± 0.2, 120 rpm) at 168 h incubation. PCP degradation was also recorded at 20°C (62.75%) and 37°C (83.33%); pH 6 (70%) and pH 9 (75.16%); 50 rpm (73.33%) and 200 rpm (91.63%). The simultaneous release of chloride ion up to 90.8 mg/l emphasized the bacterial dechlorination in the medium. GC–MS analysis revealed the formation of low molecular weight compound, i.e., 6-chlorohydroxyquinol, 2,3,4,6-tetrachlorophenol and tetrachlorohydroquinone, from degraded sample as compared to control.  相似文献   

16.
17.
Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml−1 L-tryptophan ranges from 0.60 to 3.0 μg IAA ml−1 as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. Rhizospheric isolates exhibit relatively more IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC–MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production by Bacillus spp. (GC–MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata.  相似文献   

18.
Rhipicephalus sanguineus ticks (n = 63) collected from five dogs (two adults and three puppies) housed in a kennel were screened for Ehrlichial agents (Ehrlichia canis, E. chaffeensis, and E. ewingii) using a species-specific multicolor real-time TaqMan PCR amplification of the disulphide bond formation protein (dsb) gene. Ehrlichia chaffeensis DNA was detected in 33 (56%) ticks, E. canis DNA was detected in four (6%) ticks, and one tick was coinfected. The E. chaffeensis and E. canis nucleotide sequences of the amplified dsb gene (374 bp) obtained from the Cameroonian R. sanguineus ticks were identical to the North American genotypes.  相似文献   

19.
Potato late blight disease, which is caused by the fungus Phytophthora infestans, results in considerable loss of potato crop yield worldwide. Developing new bio-agents to control this disease is desirable. Xenocoumacin 1 (Xcn1) is an antibacterial substance from the entomopathogenic nematode symbiotic bacterium, Xenorhabdus nematophila var. pekingensis. In this study, we evaluated the antifungal activity of Xcn1, along with its potential activity against Phytophthora infestans, in vitro and in vivo. The results showed that Xcn1 exhibits strong antifungal activity against five species of Phytophthora, with EC50 values ranging from 0.25 to 4.17 μg/mL. Xcn1 not only inhibited mycelial growth of P. infestans, reaching 100% inhibition at 1.5 μg/mL of Xcn1, but also suppressed sporangia production. Xcn1 also showed potent in vivo activity against P. infestans, with 92.63% and 80.27% in detached plants and potted plants, respectively, in comparison with the control. Therefore, Xcn1 has antibiotic activities against P. infestans both in vitro and in vivo.  相似文献   

20.
HESX1 plays a key role in the development of the forebrain and pituitary gland and produces potential effects on performance traits. The objective of this study was to detect and assess the associations of the possible polymorphisms of six loci within HESX1 gene with performance traits in Chinese 1,119 goats. Only one novel SNP (NM_001494116:g.307049A > G) locating on IVS1 + 348A > G was identified and detected by HaeIII forced-RFLP-PCR. The frequencies of allele “G” varied from 0.025 to 0.245 in analyzed populations with the Hardy–Weinberg equilibrium (P > 0.05). Genotypic and allelic frequencies were found to be significantly different in four breeds (χ2 = 147.674, df = 6, P < 0.001; χ2 = 157.250, df = 3, P < 0.001, respectively), implying that the distribution of genotypic and allelic frequencies of goat HESX1 gene was significantly associated with different goat utilities (cashmere, meat and dairy). Association analysis results revealed no significant effects of caprine HESX1 gene on body sizes in XNSN population (P > 0.05) and cashmere traits in IMWC population (P > 0.05). Significant statistical of HESX1 gene with body weight was found (*P < 0.05). The genotype AA showed significantly higher body weight than those of AG in 2-year-old age (*P < 0.05), while the AA genotype was senior to AG genotype in 4-year-old body weight trait (*P < 0.05). These suggestions indicated that the HESX1 gene has significant effect on goat body weight depending on ages, which is accordance with the function repressor of the HESX1.  相似文献   

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