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31.
Two secreted signaling molecules, wingless (wg) and decapentaplegic (dpp), are required to specify the heart in Drosophila. wg and dpp are also required to specify other cell types within the mesoderm and in many other regions of the embryo. Because the spatial patterns of wg and dpp are dynamic, different populations of mesodermal cells are exposed to different combinations of wg and/or dpp at different times. To determine whether the patterns of wg and dpp expression provide unique positional information for the specification of heart precursors, we altered these patterns. Our data suggest that wg and dpp contribute progressively to the elaboration of the expression pattern of the mesoderm-specific homeobox-containing gene tinman (tin), and that the overlap of wg and dpp at an early stage (9) as well as at a later stage (11) in the presence of tin-expressing cells directs cardiac-specific differentiation. Furthermore, ectopic tin expression in the ectoderm at wg/dpp intersects (the primordia of the thoracic imaginal disks) also leads to cardiac-specific differentiation, suggesting that tin confers mesoderm-specificity to the wg/dpp response. We conclude that ectopic heart can be generated by altering the patterns of wg and dpp within the tin-expressing mesoderm, or by ectopic induction of tin within the wg- and dpp-expressing ectoderm. 相似文献
32.
Per?GP?EricsonEmail author Ida?Envall Martin?Irestedt Janette?A?Norman 《BMC evolutionary biology》2003,3(1):16
Background
Phylogenetic hypotheses of higher-level relationships in the order Charadriiformes based on morphological data, partly disagree with those based on DNA-DNA hybridisation data. So far, these relationships have not been tested by analysis of DNA sequence data. Herein we utilize 1692 bp of aligned, nuclear DNA sequences obtained from 23 charadriiform species, representing 15 families. We also test earlier suggestions that bustards and sandgrouses may be nested with the charadriiforms. The data is analysed with methods based on the parsimony and maximum-likelihood criteria. 相似文献33.
34.
The legend for Fig. 6 should read "Collective silos ("Cenobio de Valeron," Gran Canaria)." instead of "Collective silos ("Cueva del Rey," Tejeda, Gran Canaria)." 相似文献
35.
Applications of supercritical fluid extraction and chromatography in forensic science 总被引:2,自引:0,他引:2
Radcliffe C Maguire K Lockwood B 《Journal of biochemical and biophysical methods》2000,43(1-3):261-272
Supercritical fluid technology is a rapidly expanding analytical technique. Here we give a brief insight into the background of supercritical fluid technology and how supercritical fluid extraction and supercritical fluid chromatography work in analysis. The applications of these two techniques in forensic science are known to be important. The main area of forensic use of supercritical fluid technology is in the sample preparation and separation of drugs of abuse particularly opiates, cannabinoids, cocaine and sedatives. Supercritical fluid technology can be used for both time-of-death-related drug analysis and for obtaining information relating to long term drug abuse. We also give a review of the use of supercritical fluids in two other major forensic areas, fingerprinting and the extraction and separation of explosives from both bombing events and gunshot residues. Overall we show that supercritical fluid technology is fast becoming a major part of forensic investigations and that it is an invaluable analysis technique. 相似文献
36.
Yasmin Husaini Glen P. Lockwood Trung V. Nguyen Vicky Wang-Wei Tsai Mohammad G. Mohammad Pamela J. Russell David A. Brown Samuel N. Breit 《PloS one》2015,10(2)
The divergent TGF-β superfamily member, macrophage inhibitory cytokine-1 (MIC-1/GDF15), is overexpressed by most cancers, including prostate cancer (PCa). Whilst its circulating levels are linked to cancer outcome, the role MIC-1/GDF15 plays in cancer development and progression is incompletely understood. To investigate its effect on PCa development and spread, we have used TRAMP prostate cancer prone mice bearing a germline deletion of MIC-1/GDF15 (TRAMPMIC-/-). On average TRAMPMIC-/- mice died about 5 weeks earlier and had larger prostatic tumors compared with TRAMP mice that were wild type for MIC-1/GDF15 (TRAMPMIC+/+). Additionally, at the time of death or ethical end point, even when adjusted for lifespan, there were no significant differences in the number of mice with metastases between the TRAMPMIC+/+ and TRAMPMIC-/- groups. However, consistent with our previous data, more than twice as many TRAMP mice overexpressing MIC-1/GDF15 (TRAMPfmsmic-1) had metastases than TRAMPMIC+/+ mice (p<0.0001). We conclude that germ line gene deletion of MIC-1/GDF15 leads to increased local tumor growth resulting in decreased survival consistent with an overall protective role for MIC-1/GDF15 in early primary tumor development. However, in advancing disease, as we have previously noted, MIC-1/GDF15 overexpression may promote local invasion and metastatic spread. 相似文献
37.
David J. Chandler Kristian S. Hansen Bhabananda Mahato Joydeepa Darlong Annamma John Diana N. J. Lockwood 《PLoS neglected tropical diseases》2015,9(1)
Background
Erythema nodosum leprosum (ENL) is a common immune-mediated complication of lepromatous (LL) and borderline lepromatous (BL) leprosy. Most patients experience chronic or multiple acute ENL over many years during an economically active period of their lives. Understanding the economic burden of ENL is essential to provide effective patient support, yet this area has not been investigated.Methods
Ninety-one patients with LL or BL leprosy attending a leprosy hospital in Purulia district of West Bengal, India, were interviewed using a structured questionnaire. Cases (n = 53) were identified as those who had one or more episodes of ENL within the last 3 years. Controls (n = 38) had LL or BL leprosy but no history of ENL. Data were collected on household income, direct and indirect costs, and coping strategies.Findings
The total household cost was Rs 1543 per month or 27.9% (IQR 13.2-52.6) of monthly household income for cases, and Rs 237 per month or 4.9% (IQR 1.7-13.4) of monthly household income for controls. Indirect costs accounted for 65% of total household costs for cases. Direct costs accounted for the remaining 35% of household costs, and resulted almost entirely from treatment-seeking in the private sector. Total household costs exceeded 40% of household income for 37.7% of cases (n = 20) and 2.6% of controls (n = 1) [1 USD = 59 INR].Interpretation
Households affected by ENL face significant economic burden and are at risk of being pushed further into poverty. Health policy should acknowledge the importance of private sector provision and the significant contribution to total household costs of lost productivity (indirect cost). Further work is needed to explore this area and identify solutions. 相似文献38.
Crimmins DL Brada NA Lockwood CM Griest TA Waldemer RJ Cervinski MA Ohlendorf MF McQuillan JJ Ladenson JH 《Biotechnology and applied biochemistry》2010,57(4):127-138
Recombinant GST (glutathione transferase) proteins are widely used as immunogens to generate polyclonal antibodies. Advantages of using GST proteins include: commercially available cloning vectors, vast literature for protein expression in Escherichia coli, the ease of protein purification, immunogen can be used as an ELISA standard and GST can be removed in some systems. However, there are disadvantages: GST oligomerization, inclusion body formation and target protein insolubility after GST removal. Perhaps the most detrimental is the significant generation of anti-GST antibodies by the host animal. A two-column procedure using a glutathione-GST column and a glutathione-(GST-protein) column can yield affinity-purified anti-(GST-protein) polyclonal antibody. Several passes over the first column are often required, though, to completely extract the anti-GST antibodies from the immune sera. We reasoned that knowledge of the target protein linear epitope(s) would allow construction of a peptide affinity resin for a single-pass 'one and done' purification termed ETRAP (efficient trapping and purification). In the present paper, we describe our efforts and present data on rabbits and sheep immunized with GST proteins having target protein molecular masses of ~8, 21 and 33?kDa. The titre and purity of the target antibodies using the ETRAP protocol were comparable to the more laborious multi-column purifications but with a considerable saving in time. 相似文献
39.
40.
Comparative Biogeography of Grasshoppers (Orthoptera: Acrididae) in North America and Siberia: Applications to the Conservation of Biodiversity 总被引:2,自引:0,他引:2
The objective of this study was to apply knowledge of holarctic grasshopper biogeography in representative, temperate ecosystems (Russia, South Siberia, Sayans region; 685,000km2 and USA, Wyoming; 272,000km2) to develop a comparative basis for understanding and conserving insect biodiversity. Maps of species distributions and vegetation zones were digitized, and a Geographic Information System was used to identify habitats with the greatest biodiversity and to characterize this diversity as a function of selected attributes. With respect to subfamilies, the greatest differences were in cold, mesic zones, where gomphocerines and melanoplines were dominant in Sayans and Wyoming, respectively. In terms of mobility, the Sayans has more flightless species and individuals, with the taiga supporting the greatest frequency of flightless acridids in both countries. With regard to feeding types, the diversity and richness of graminivores and forbivores were similar in the two regions, but mixed feeders were much more frequent in Wyoming. In the Sayans and Wyoming, pest species were most common in boreal and prairie zones, respectively. Ecoregions with a high diversity of pests also supported a high diversity of rare species. Shrub and desert zones supported many rare species in both countries. Thus, in terms of conservation, the Sayans' acridofauna appears to be at greater risk in terms of ecological vulnerability; acridid biodiversity is dispersed among habitats, with high frequencies of flightless and oligophagous species. The acridofauna of Wyoming could be conserved in fewer habitats than in the Sayans, but these habitats are subject to considerable human disturbance. 相似文献