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21.
Van der Woude syndrome (VWS) is the most frequent form of syndromic clefting. Linkage analysis has localized the gene between D1S245 and D1S414, an interval of 4.1 cM with the following order of loci: centromere–D1S245/D1S471–D1S491–D1S205–D1S414–telomere. A microdeletion around D1S205 aided in narrowing the critical region to D1S491–D1S414 by heterozygosity testing. In this study, the location was refined by detection of a recombinant with D1S205 in a new family, indicating that VWS lies between D1S491 and D1S205, a 1.6-cM interval. A roughly 3.5-Mb YAC contig was built from D1S245 through D1S414, encompassing the interval D1S491–D1S205 in level 1 or level 2 paths. Clones were assembled by sequence tagged site (STS) content using the five polymorphic markers from above, four novel STSs identified from YAC ends, and a new STS derived from probe CRI-L461 (D1S70). D1S70 was assigned to the critical region. One single YAC, yCEPH785B2, contains both flanking STSs (D1S491, D1S205). STS content mapping suggests neither chimerism nor deletion of yCEPH785B2 but does suggest that the maximum size of the critical region is approximately 850 kb. All STSs were tested for their presence on a somatic cell hybrid containing the microdeleted chromosome 1 as the sole human chromosome 1 component. Both the proximal and distal ends of the microdeletion mapped to the 850-kb YAC, yCEPH785B2. Therefore, the microdeletion overlapped the critical region, confirming the genetic recombinant data. 相似文献
22.
Plant regeneration via somatic embryogenesis in ginger 总被引:5,自引:0,他引:5
A. Kackar S. R. Bhat K. P. S. Chandel S. K. Malik 《Plant Cell, Tissue and Organ Culture》1993,32(3):289-292
Embryogenic callus cultures of ginger were induced from young leaf segments taken from in vitro shoot cultures. Among the four auxins tested in Murashige & Skoog medium, dicamba at 2.7 M was most effective in inducing and maintaining embryogenic cultures. Efficient plant regeneration was achieved when embryogenic cultures were transferred to Murashige & Skoog medium containing 8.9 M benzyladenine. Histological studies revealed various stages of somatic embryogenesis characteristic of the monocot system. The in vitro-raised plants have been established in soil.Abbreviations BA
benzyladenine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- IAA
indole-3-acetic acid
- MS
Murashige and Skoog
- NAA
naphthaleneacetic acid 相似文献
23.
24.
Cotton ovules collected during late September with prevalent night cool temperature (15°C), cultured at 30°C/15°C i.e. cycling temperatures in Beasley and Ting medium had very few epidermal cells showing bulging. Supplementing cultures with guaianolide derivative I (E-13 methyldehydrocostus lactone) promoted fibre initiation. At—1 day preanthesis (DPA), IAA oxidase activity declined in guaianolide-treated cultures but increased during the elongation phase and was enhanced during the secondary wall thickening phase. However, o-diphenol oxidase activity was adversely affected during the fibre initiation phase. The activities of all the other enzymes studied viz. acid invertase, phenylalanine ammonia lyase, -glucosidase and IAA oxidase increased, except -galactosidase, during the later phase in comparison with the controls. The present study indicates that guaianolide derivative I triggers early initiation and promotes fibre elongation by regulatin o-diphenols and IAA-oxidation levels, which in turn check wall loosening. Considerable enhancement in the soluble acid invertase activity by this compound suggests its role in apoplastic sucrose hydrolysis, thereby preventing its accumulation.Abbreviations DPA
days pre anthesis
- DAC
days after culturing
- DAA
days after anthesis 相似文献
25.
Shlomit Katz Zvy Dubinsky Chana Rothmann Zvi Malik Michael Friedlander 《Journal of phycology》1997,33(3):425-432
The novel method of Fourier transform multi-pixel spectroscopy was used for the nondestructive analysis of and comparison of pigmentation in different regions of live thalli of the red alga Porphyra linearis. Because the thallus in this alga consists of a monolayer of nonoverlapping cells, we were able to analyze the pigmentation of single cells by combining light absorbance with natural fluorescence data. From the image of each cell in the vegetative male and female reproductive and holdfast regions, more than 4 ± 104 fluorescence and absorbance spectra were obtained. Specific pigments in the different regions were localized by the use of a software program of similarity mapping followed by image construction. The reconstructed images revealed subcellular localization of each pigment according to specific spectroscopic fingerprints. The results showed that the vegetative and female reproductive cell types had a significantly higher content of phycoerythrin than of phycocyanin, and quite similar chlorophyll a levels. Most of the holdfast cells were poorly pigmented, but had more chlorophyll a than phycoerythrin or phycocyanin. The male reproductive cells contained only traces of pigments. Thus, by using Fourier transform multipixel spectroscopy, we were able to characterize the pigmentation of different regions of the thallus and follow the distribution patterns of the different pigments on the subcellular level along the differentiation gradient of the alga. 相似文献
26.
Recombinant adeno-associated virus mediates a high level of gene transfer but less efficient integration in the K562 human hematopoietic cell line. 总被引:7,自引:4,他引:3 下载免费PDF全文
P Malik S A McQuiston X J Yu K A Pepper W J Krall G M Podsakoff G J Kurtzman D B Kohn 《Journal of virology》1997,71(3):1776-1783
We tested the ability of a recombinant adeno-associated virus (rAAV) vector to express and integrate exogenous DNA into human hematopoietic cells in the absence of selection. We developed an rAAV vector, AAV-tNGFR, carrying a truncated rat nerve growth factor receptor (tNGFR) cDNA as a cell surface reporter under the control of the Moloney murine leukemia virus (MoMuLV) long terminal repeat. An analogous MoMuLV-based retroviral vector (L-tNGFR) was used in parallel, and gene transfer and expression in human hematopoietic cells were assessed by flow cytometry and DNA analyses. Following gene transfer into K562 cells with AAV-tNGFR at a multiplicity of infection (MOI) of 13 infectious units (IU), 26 to 38% of cells expressed tNGFR on the surface early after transduction, but the proportion of tNGFR expressing cells steadily declined to 3.0 to 3.5% over 1 month of culture. At an MOI of 130 IU, nearly all cells expressed tNGFR immediately posttransduction, but the proportion of cells expressing tNGFR declined to 62% over 2 months of culture. The decline in the proportion of AAV-tNGFR-expressing cells was associated with ongoing losses of vector genomes. In contrast, K562 cells transduced with the retroviral vector L-tNGFR expressed tNGFR in a constant fraction. Integration analyses on clones showed that integration occurred at different sites. Integration frequencies were estimated at about 49% at an MOI of 130 and 2% at an MOI of 1.3. Transduction of primary human CD34+ progenitor cells by AAV-tNGFR was less efficient than with K562 cells and showed a declining percentage of cells expressing tNGFR over 2 weeks of culture. Thus, purified rAAV caused very high gene transfer and expression in human hematopoietic cells early after transduction, which steadily declined during cell passage in the absence of selection. Although the efficiency of integration was low, overall integration was markedly improved at a high MOI. While prolonged episomal persistence may be adequate for gene therapy of nondividing cells, a very high MOI or improvements in basic aspects of AAV-based vectors may be necessary to improve integration frequency in the rapidly dividing hematopoietic cell population. 相似文献
27.
Genetic variation at the Major Histocompatibility Complex locus DQ beta was
analyzed in 233 beluga whales (Delphinapterus leucas) from seven
populations: St. Lawrence Estuary, eastern Beaufort Sea, eastern Chukchi
Sea, western Hudson Bay, eastern Hudson Bay, southeastern Baffin Island,
and High Arctic and in 12 narwhals (Monodon monoceros) sympatric with the
High Arctic beluga population. Variation was assessed by amplification of
the exon coding for the peptide binding region via the polymerase chain
reaction, followed by either cloning and DNA sequencing or single-stranded
conformation polymorphism analysis. Five alleles were found across the
beluga populations and one in the narwhal. Pairwise comparisons of these
alleles showed a 5:1 ratio of nonsynonymous to synonymous substitutions per
site leading to eight amino acid differences, five of which were
nonconservative substitutions, centered around positions previously shown
to be important for peptide binding. Although the amount of allelic
variation is low when compared with terrestrial mammals, the nature of the
substitutions in the peptide binding sites indicates an important role for
the DQ beta locus in the cellular immune response of beluga whales.
Comparisons of allele frequencies among populations show the High Arctic
population to be different (P < or = .005) from the other beluga
populations surveyed. In these other populations an allele, Dele-DQ
beta*0101-2, was found in 98% of the animals, while in the High Arctic it
was found in only 52% of the animals. Two other alleles were found at high
frequencies in the High Arctic population, one being very similar to the
single allele found in narwhal.
相似文献
28.
The ATP content of 7-day-old Avena sativa leaves during senescence in dark and in light, and after treatment with cytokinins and other reagents, has been determined by the luciferin-luciferase method. Special care was taken to avoid decomposition of the ATP, and a detailed procedure is presented for ATP analysis at the picomole level. Preliminary experiments with several inhibitors of photophosphorylation suggest, though not conclusively, that the delaying effect of light on senescence is mediated by photophosphorylation. The ATP values of the leaves senescing in darkness are found to increase in parallel with the large increase in respiratory rate, and kinetin prevents this increase just as completely as it prevents the respiratory rise. It is concluded that the respiratory increase in senescence cannot be simply due to uncoupling. In light the ATP level also rises, though more slowly, and again kinetin prevents this rise. l-Serine, which promotes dark senescence, does not significantly modify the dark ATP level, but both arginine and kinetin, which antagonize the action of serine on senescence, greatly lower the ATP level below that on serine alone. Cycloheximide has a similar effect, and the combination of cycloheximide and kinetin lowers the ATP level drastically. Fusicoccin, which opens stomata in the dark, correspondingly maintains the ATP at a low level. Thus, in general, a low level of ATP is associated with the prevention of dark senescence, i.e. probably with ATP utilization, and the ATP level at any time may thus be determined more by the rate of utilization than by the efficiency of respiratory coupling. 相似文献
29.
30.
In vivo and in vitro activities of nitrate reductase were assayedin Crotalaria juncea pollen suspension cultures. This enzymewas found to be substrate-inducible and enhanced activity wasobserved when it was extracted with cysteine buffer or incubatedwith NADH (0.6 mM) at 25?C or when the germinated pollen grainswere treated with red light for 10 min. Enzymes of ammonia assimilation,glutamate dehydrogenase and glutamate synthetase, and also thepentose phosphate-shunt enzyme, glucose-6-phosphate dehydrogenase,which catalyzes the step that provides reducing power to thesystem, are described. (Received October 20, 1977; ) 相似文献