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71.
Margaret L. Van Keuren Galina B. Gavrilina Wanda E. Filipiak Michael G. Zeidler Thomas L. Saunders 《Transgenic research》2009,18(5):769-785
Transgenic mice are widely used in biomedical research to study gene expression, developmental biology, and gene therapy models.
Bacterial artificial chromosome (BAC) transgenes direct gene expression at physiological levels with the same developmental
timing and expression patterns as endogenous genes in transgenic animal models. We generated 707 transgenic founders from
86 BAC transgenes purified by three different methods. Transgenesis efficiency was the same for all BAC DNA purification methods.
Polyamine microinjection buffer was essential for successful integration of intact BAC transgenes. There was no correlation
between BAC size and transgenic rate, birth rate, or transgenic efficiency. A narrow DNA concentration range generated the
best transgenic efficiency. High DNA concentrations reduced birth rates while very low concentrations resulted in higher birth
rates and lower transgenic efficiency. Founders with complete BAC integrations were observed in all 47 BACs for which multiple
markers were tested. Additional founders with BAC fragment integrations were observed for 65% of these BACs. Expression data
was available for 79 BAC transgenes and expression was observed in transgenic founders from 63 BACs (80%). Consistent and
reproducible success in BAC transgenesis required the combination of careful DNA purification, the use of polyamine buffer,
and sensitive genotyping assays. 相似文献
72.
Nest-mate recognition template of guard honeybees (Apis mellifera) is modified by wax comb transfer 下载免费PDF全文
Couvillon MJ Caple JP Endsor SL Kärcher M Russell TE Storey DE Ratnieks FL 《Biology letters》2007,3(3):228-230
In recognition, discriminators use sensory information to make decisions. For example, honeybee (Apis mellifera) entrance guards discriminate between nest-mates and intruders by comparing their odours with a template of the colony odour. Comb wax plays a major role in honeybee recognition. We measured the rejection rates of nest-mate and non-nest-mate worker bees by entrance guards before and after a unidirectional transfer of wax comb from a 'comb donor' hive to a 'comb receiver' hive. Our results showed a significant effect that occurred in one direction. Guards in the comb receiver hive became more accepting of non-nest-mates from the comb donor hive (rejection decreased from 70 to 47%); however, guards in the comb donor hive did not become more accepting of bees from the comb receiver hive. These data strongly support the hypothesis that the transfer of wax comb increases the acceptance of non-nest-mates not by changing the odour of the bees, but by changing the template used by guards. 相似文献
73.
Summary All forests, including commercial plantations, provide a range of habitats for conserving and enhancing elements of native biodiversity. However, the biodiversity values of commercial plantations will depend on the management practices adopted on site, as well as the landscape context of the plantation. The present study describes a generic, quantitative method for assessing the potential biodiversity benefits that might be derived from a plantation, depending on the management practices adopted. This method is based on existing ecological design and management principles. The Plantation Biodiversity Benefits Score (PBBS) was designed to be repeatable and practical to apply. The method can be used either as a stand-alone tool or as part of an integrated framework to assess and compare the commercial and environmental benefits that can be derived from different layouts, management practices and locations of plantations anywhere in Australia. 相似文献
74.
Esophageal temperature threshold for sweating decreases before ovulation in premenopausal women 总被引:1,自引:0,他引:1
The purpose ofthis study was to test the hypothesis that regulated body temperatureis decreased in the preovulatory phase in eumenorrheic women. Six womenwere studied in both the preovulatory phase (Preov-2;days 9-12), which was 1-2days before predicted ovulation when 17-estradiol(E2) was estimated to peak, andin the follicular phase (F; days2-6). The subjects walked on a treadmill (~225W · m2)in a warm chamber (ambient temperature = 30°C; dew-pointtemperature = 11.5°C) while heavily clothed.E2, esophageal temperature(Tes), local skin temperatures,and local sweating rate were measured. The estimate of when theE2 surge would occur was correctfor four of six subjects. In these four subjects,E2 increased(P 0.05) from 42.0 ± 24.5 pg/mlduring F to 123.2 ± 31.3 pg/ml during Preov-2. RestingTes was 37.02 ± 0.20°Cduring F and 36.76 ± 0.28°C during Preov-2(P 0.05). TheTes threshold for sweating wasdecreased (P 0.05) from 36.88 ± 0.27°C during F to 36.64 ± 0.35°C during Preov-2. Both meanskin and mean body temperatures were decreased during rest in Preov-2group. The hypothesis that regulated body temperature is decreasedduring the preovulatory phase is supported. 相似文献
75.
Devin C Koestler Brock C Christensen Margaret R Karagas Carmen J Marsit Scott M Langevin Karl T Kelsey John K Wiencke E Andres Houseman 《Epigenetics》2013,8(8):816-826
The potential influence of underlying differences in relative leukocyte distributions in studies involving blood-based profiling of DNA methylation is well recognized and has prompted development of a set of statistical methods for inferring changes in the distribution of white blood cells using DNA methylation signatures. However, the extent to which this methodology can accurately predict cell-type proportions based on blood-derived DNA methylation data in a large-scale epigenome-wide association study (EWAS) has yet to be examined. We used publicly available data deposited in the Gene Expression Omnibus (GEO) database (accession number GSE37008), which consisted of both blood-derived epigenome-wide DNA methylation data assayed using the Illumina Infinium HumanMethylation27 BeadArray and complete blood cell (CBC) counts among a community cohort of 94 non-diseased individuals. Constrained projection (CP) was used to obtain predictions of the proportions of lymphocytes, monocytes and granulocytes for each of the study samples based on their DNA methylation signatures. Our findings demonstrated high consistency between the average CBC-derived and predicted percentage of monocytes and lymphocytes (17.9% and 17.6% for monocytes and 82.1% and 81.4% for lymphocytes), with root mean squared error (rMSE) of 5% and 6%, for monocytes and lymphocytes, respectively. Similarly, there was moderate-high correlation between the CP-predicted and CBC-derived percentages of monocytes and lymphocytes (0.60 and 0.61, respectively), and these results were robust to the number of leukocyte differentially methylated regions (L-DMRs) used for CP prediction. These results serve as further validation of the CP approach and highlight the promise of this technique for EWAS where DNA methylation is profiled using whole-blood genomic DNA. 相似文献
76.
Teklehaimanot?HaileselassieEmail author Margaret?mollel Io?Skogsmyr 《Evolutionary ecology》2005,19(3):275-288
Plants have evolved many mechanisms to increase the chance of gene dispersal mainly through pollen and environmental factors play an important role. Understanding the mechanism behind gene dispersal is therefore crucial in the correct evaluation of the use of genetically modified crops for cultivation. In this paper we address the question of weather nutrient availability for the female affects the outcome of pollen competition between two pollen donor cultivars of Cucumis sativus. We do this by carrying out controlled crosses of female plants grown at three different nutrient levels. We separated the effect of a specific donor from the effect of pollen tube growth rate by using reversed crosses of fast and slow pollen. Our results show that female effects on siring ability vary with nutrient level. Pollen with a high pollen tube growth rate was more successful when nutrient availability for the female was high. This could be the result of selection on the female to adjust preference according to environmental circumstances. Pollen tube growth rate was measured under nutrient rich circumstances, thus high performers possessed traits adapted to a nutrient rich situation. Due to trade-off effects, these traits might not be advantageous in poor environments. Instead, individuals adapted to low nutrient circumstances will have a higher pollen tube growth rate. If siring ability varies with the environment of the recipient plant, this means that assessments of gene flow must account for this variation and include both pollen donors and recipient plants subjected to a range of environmental circumstances. In risk assessments of transgenic plants, plants are often kept under experimental, homogenous conditions. If our results also apply to other species, estimates of gene flow under constant conditions may be misleading. Selection on siring ability and female preference have fundamental effects on gene flow and need to be considered in risk assessments of transgenic plants.Co-ordinating editor: I. Olivieri 相似文献
77.
78.
Background
Patients with New World cutaneous leishmaniasis (NWCL) caused by Leishmania Viannia are treated with parenteral sodium stibogluconate (SbV) to reduce the risk of development of mucocutanous leishmaniasis. Our centre manages patients with NWCL on an outpatient-basis. This study was conducted to assess the safety and efficacy of this approach.Methodology
We reviewed records of 67 consecutive NWCL patients, aged 17–61 years, treated as day-cases with 20 mg/kg/day SbV for up to 28 days at our UK centre. Data had been collected in a standardised format at the time of treatment using a care-record tool. Patients reported adverse-effects daily using a structured questionnaire. Blood tests and electrocardiograms were performed twice weekly to monitor for toxicity.Principal Findings
Parenteral SbV treatment was associated with an early, significant suppression of mean lymphocyte and platelet counts. By day four of treatment, lymphocytes reduced by 0.53×109/L (CI 0.29×109/L to 0.76×109/L, p<0.001), and platelets by 31,000/µL (CI 16,000/µL to 46,000/µL, p<0.001). SbV was further associated with significant elevation of serum alanine transaminase concentrations, with a mean peak rise of 107 iu/L by day 13 (CI 52 iu/L to 161 iu/L, p<0.001). These disturbances were temporary and did not result in adverse clinical events. Patient-described symptoms were cumulative and at three weeks of treatment, 59.6% of patients experienced myalgia and 29.8% malaise. Treatment adherence and clinical outcomes were comparable to inpatient treatment studies. A total of 1407 individual doses of SbV resulted in only 26 nights'' hospital admission, a saving of 1381 bed-days compared to inpatient treatment.Conclusions/Significance
In specialist centres, NWCL patients aged below 65 years and without co-morbidities can be safely and effectively treated without hospital admission. This reduces the cost of treatment, and is much preferred by patients. Twice weekly blood and electrocardiographic monitoring may be surplus to requirement in clinically well, low-risk patients. 相似文献79.
Emerging roles for natural microRNA sponges 总被引:2,自引:0,他引:2
80.
David K. Clarke Farooq Nasar Siew Chong J. Erik Johnson John W. Coleman Margaret Lee Susan E. Witko Cheryl S. Kotash Rashed Abdullah Shakuntala Megati Amara Luckay Becky Nowak Andrew Lackner Roger E. Price Peter Little Narender Kalyan Valerie Randolf Ali Javadian Timothy J. Zamb Christopher L. Parks Michael A. Egan John Eldridge Michael Hendry Stephen A. Udem 《Journal of virology》2014,88(12):6690-6701