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31.
G. Manders W. C. Otoni F. B. d'Utra Vaz N. W. Blackball J. B. Power M. R. Davey 《Plant cell reports》1994,13(12):697-702
Leaf and stem explants of passionfruit (Passiflora eadulis fv flavicarpa) were co-cultivated with a disarmed strain of Agrobacterium tunefaciens harbouring the co-integrate vector pMON200. Four plants of passionfruit were regenerated from leaf explants on agar-solidified Murashige and Skoog (1962) based medium containing 4.43 M 6-benzyl-aminopurine and supplemented with 86 M kanamycin sulphate. The four plants were rooted by transfer to MS based medium with 14.7 M 3-indolebutyric acid and 2.68 M -naphthyleneacetic acid for 7 d, followed by MS based medium lacking growth regulators. Both media used for rooting contained 172 M kanamycin sulphate. Rooted plants were potted and grown to maturity. Three of the plants synthesised nopaline and expressed neomycin phosphotransferase activity; DNA dot blot and polymerase chain reaction analyses confirmed the presence of the neomycin phosphotransferase gene in three plants.Abbreviations BAP
6-benzylaminopurine
- CTAB
hexadecy-Itrimethylammonium bromide
- EDTA
ethylenediaminetetraacetic acid
- IBA
3-indolebutyric acid
- MS
Murashige and Skoog (1962)
- NAA
-naphthyleneacetic acid
- NPTII
neomycin phosphotransferase II
-
nptII
neomycin phosphotransferase II gene
- PCR
polymerase chain reaction
- SDS
sodium dodecyl sulphate
- Tris
tris(hydroxymethyl)aminomethane 相似文献
32.
Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews
(genus Sorex) for the region between the tRNA(Pro) and the conserved
sequence block-F revealed variable numbers of 79-bp tandem repeats. These
repeats were found in all 19 individuals sequenced, representing three
subspecies and one closely related species of the masked shrew group (Sorex
cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an
outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an
adjacent 76-bp imperfect copy of the tandem repeats. One individual was
heteroplasmic for length variants consisting of five and seven copies of
the 79-bp tandem repeat. The sequence of the repeats is conducive to the
formation of secondary structure. A termination-associated sequence is
present in each of the repeats and in a unique sequence region 5' to the
tandem array as well. Mean genetic distance between the masked shrew taxa
and the pygmy shrew was calculated separately for the unique sequence
region, one of the tandem repeats, the imperfect repeat, and these three
regions combined. The unique sequence region evolved more rapidly than the
tandem repeats or the imperfect repeat. The small genetic distance between
pairs of tandem repeats within an individual is consistent with a model of
concerted evolution. Repeats are apparently duplicated and lost at a high
rate, which tends to homogenize the tandem array. The rate of D- loop
sequence divergence between the masked and pygmy shrews is estimated to be
15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid
sequence evolution in shrews may be due either to their high metabolic rate
and short generation time or to the presence of variable numbers of tandem
repeats.
相似文献
33.
Michael Power D. George Dixon Geoffrey Power 《Journal of Aquatic Ecosystem Stress and Recovery (Formerly Journal of Aquatic Ecosystem Health)》1994,3(2):69-79
Risk is by no means a simple concept. Natural variability and definitional problems with the concept of probability complicate the measurement and use of risk as an analytical tool. Variability requires that risk assessment methods separate natural from total risk when attempting to estimate anthropogenic risk. Failure to do so results in the over estimation of anthropogenic risk and the eventual loss of credibility for risk assessment methodologies. The common frequentist approach to probability is not consistent with anything but a modelling approach to risk assessment. When combined with its ability to account for natural variability, incorporate laboratory-assay data and offer complete statistical and experimental control, modelling is a promising approach to risk assessment. Modelling, however, is not without its drawbacks. Initialization bias can result in the over, or under, estimation of both natural and anthropogenic risk. Furthermore, model estimates are time dependent. The convergence of natural and anthropogenic risk poses problems for modelling-based risk assessment and requires clear statements as to the importance of the time dimension in risk assessment. When combined, the drawbacks to modelling-based risk assessment argue that risk should never be stated as a scalar quantity. Instead, modelling-based risk assessment should provide estimates of the complete range of risk measures (total, natural, and anthropogenic) as well as indications of convergence time. Only then can the modelling-based approach be viewed as the most appropriate means of carrying out scientifically credible risk assessment. 相似文献
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36.
P.D. Franzmann B.M. Patterson T.R. Power P.D. Nichols G.B. Davis 《Journal of applied microbiology》1996,80(6):617-625
The city of Perth contains a number of sites that have been contaminated with hydrocarbons due to leakage from petroleum underground storage tanks. Microbial biomass in groundwater and sediment cores from above and below the water table, and from within and outside a plume of hydrocarbon contamination, was examined using phospholipid fatty acid methyl ester analysis. Microbial numbers, calculated from the phospholipid content, ranged from 0·9 × 106 to 7·8 × 106 ' Escherichia coli equivalent cells' g−1 dry wt of sediment. Over 96% of the microbial biomass was attached to the sediment and the proportion of attached cells did not decrease within the plume of contaminants. The amount of biomass within aquifer samples seemed to be related more to the proximity of the rhizosphere to the shallow aquifer, and other unknown urban inputs, rather than to the effects of the plume of contaminants. Fatty acids common to many bacterial groups dominated within the plume, and as such the analyses gave limited insight into microbial community structure. For site assessment of intrinsic remediation of shallow aquifers in urban areas, estimates of microbial biomass may not provide information that is readily applicable to plume management. 相似文献
37.
OBJECTIVE: To investigate explanations for social inequalities in health with respect to health related social mobility and cumulative socioeconomic circumstances over the first three decades of life. DESIGN: Longitudinal follow up. SETTING: Great Britain. SUBJECTS: Data from the 1958 birth cohort study (all children born in England, Wales, and Scotland during 3-9 March 1958) were used, from the original birth survey and from sweeps at 16, 23, and 33 years. MAIN OUTCOME MEASURES: Subjects'' own ratings of their health; social differences in self rated health at age 33. RESULTS: Social mobility varied by health status, with those reporting poor health at age 23 having higher odds of downward mobility than of staying in same social class. Men with poor health were also less likely to be upwardly mobile. Prevalence of poor health at age 33 increased with decreasing social class: from 8.5% in classes I and II to 17.7% in classes IV and V among men, and from 9.4% to 18.8% among women. These social differences remained significant after adjustment for effects of social mobility. Health inequalities attenuated when adjusted for social class at birth, at age 16, or at 23 or for self rated health at age 23. When adjusted for all these variables simultaneously, social differences in self rated health at age 33 were substantially reduced and no longer significant. CONCLUSIONS: Lifetime socioeconomic circumstances accounted for inequalities in self reported health at age 33, while social mobility did not have a major effect on health inequalities. 相似文献
38.
大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育 总被引:1,自引:0,他引:1
本实验用免疫组织化学ABC法研究了大鼠胼胝体内神经肽Y免疫反应阳性(NPY-IR)纤维的生后发育。结果发现,许多NPY-IR纤维在大鼠出生时便存在于胼胝体内。NPY-IR胼胝体纤维的密度在生后1周内继续逐渐增高,在第2周内达到最高峰。之后,NPY-IR胼胝体纤维的密度逐渐下降,至第3周末时接近成年时的水平,即仅有少量NPY-IR纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多NPY-IR胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。 相似文献
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40.
Alexander A. Kortt Robin E. Guthrie Mark G. Hinds Barbara E. Power Neva Ivancic J. Bruce Caldwell L. Clem Gruen Raymond S. Norton Peter J. Hudson 《Journal of Protein Chemistry》1995,14(3):167-178
The VH domain of anti-influenza neuraminidase antibody NC41, with and without a C-terminal hydrophilic marker peptide (FLAGTM), has been expressed in high yield (15–27 mg/L) inEscherichia coli. Both forms were secreted into the periplasm where they formed insoluble aggregates which were solubilized quantitatively with 2 M guanidine hydrochloride and purified to homogeneity by ion-exchange chromatography. The VH-FLAG was composed of three isoforms (pI values of 4.6, 4.9, and 5.3) and the VH molecule was composed of two isoforms with pI values of 5.1 and 6.7; the difference between the VH isoforms was shown to be due to cyclization of the N-terminal glutamine residue in the pI 5.1 isoform. At 20°C and concentrations of 5–10mg/ml the VH domain dimerized in solution and then partly precipitated, resulting in the broadening of resonances in its1H NMR spectrum. Reagents such as CHAPS,n-octylglucoside, and ethylene glycol, which presumably mask the exposed hydrophobic interface of the VH molecule, prevented dimerization of the VH and permitted good-quality NMR spectra on isotope-labeled protein to be obtained. 相似文献