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1.
Indirect evidence suggests that legumes can adjust rapidly theresistance of their root nodules to O2 diffusion. Here we describeexperiments using O2 specific micro-electrodes and dark fieldmicroscopy to study directly the operation of this diffusionbarrier. The O2 concentration sensed by the electrode decreasedsharply in the region of the inner cortex and was less than1.0 mmol m3 throughout the infected tissue in nodulesof both pea (Pisum sativum) and french bean (Phaseolus vulgaris).In a number of experiments the ambient O2 concentration wasincreased to 40% while the electrode tip was just inside theinner cortex. In 13 out of 21 cases the O2 concentration atthis position either remained low and unchanged or increasedirreversibly to near ambient values. In the remaining casesthe O2 concentration increased after 1 to 2.5 min and then decreasedto its former value. These results are ascribed to an increasein resistance of the barrier in response to increased O2 fluxinto the nodule. It was shown microscopically that air spacesboth at the boundary between the infected zone and the innercortex, and within the infected zone started to disappear 3min after nodules were exposed to high ambient O2 concentrationsand had disappeared completely after 8 min. These spaces werenot changed by exposure of the nodule for 10 min to either N2or air. Key words: Oxygen, root nodules, air spaces 相似文献
2.
Evolution of the 28S ribosomal RNA gene in anurans: regions of variability and their phylogenetic implications 总被引:1,自引:0,他引:1
Fifteen restriction sites were mapped to the 28S ribosomal RNA gene of
individuals representing 54 species of frogs, two species of salamanders, a
caecilian, and a lungfish. Eight of these sites were present in all species
examined, and two were found in all but one species. Alignment of these
conserved restriction sites revealed, among anuran 28S rRNA genes, five
regions of major length variation that correspond to four of 12 previously
identified divergent domains of this gene. One of the divergent domains
(DD8) consists of two regions of length variation separated by a short
segment that is conserved at least throughout tetrapods. Most of the
insertions, deletions, and restriction-site variations identified in the
28S gene will require sequence-level analysis for a detailed reconstruction
of their history. However, an insertion in DD9 that is coextensive with
frogs in the suborder Neobatrachia, a BstEII site that is limited to
representatives of two leptodactylid subfamilies, and a deletion in DD10
that is found only in three ranoid genera are probably synapomorphies.
相似文献
3.
K. Hosaka G. A. de Zoeten R. E. Hanneman Jr. 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,75(5):741-745
Summary The chloroplast DNA (ctDNA) of Solanum tuberosum ssp. tuberosum (T type) and S. chacoense (W type) yield five different restriction fragment patterns with five different restriction endonucleases. DNA-DNA hybridization tests revealed that these differences were all caused by one physical deletion (about 400 bp in size) in the ctDNA of ssp. tuberosum. This suggests that T type ctDNA of the common potato and of Chilean tuberosum originated from W type ctDNA. The deleted region of the T type ctDNA is probably not concerned with gene-cytoplasmic male sterility.Reference to a specific brand or firm name does not constitute endorsement by the U.S. Department of Agriculture over others of a similar nature not mentioned 相似文献
4.
Summary The phenomenon of interspecific incompatibility between various wild tuber-bearing and closely related non-tuber-bearing Solanum species was studied. One area of investigation included an examination of possible protein interactions in the incompatibility reaction using SDS electrophoresis. Pollen tube inhibition and morphology were examined in conjunction with biochemical analysis. Two sets of crosses were examined: interspecific tuber-bearing species crosses and interspecific tuber-bearing × non-tuber-bearing species crosses. These crosses had consistent pollen tube inhibition in the upper one-third of the style. The upper third of the styles of incompatibly pollinated, compatibly pollinated, and unpollinated styles was studied under fluorescence microscopy to observe pollen tube growth and morphology. Interspecific tuber-bearing × non-tuber-bearing species crosses demonstrated consistent pollen tube inhibition just below the stigma with frequent pollen tube swelling and bursting and extensive callose deposition along the pollen tube wall. Interspecific tuber-bearing species crosses had pollen tube inhibition further down the style with pollen tube tip tapering and extensive callose deposition. Stylar proteins of the lower two-thirds of the styles were analyzed with SDS electrophoresis. No unique protein differences were found to be specifically associated with the interspecific incompatibility reaction in this portion of the style.Cooperative investigation of the U.S. Department of Agriculture, Agricultural Research Service, and the Wisconsin Experiment Station. Supported in part by the USDA, Cooperative States Research Service Competitive grant no. 83-CRCR-1-1253 相似文献
5.
J. B. Bamberg R. E. Hanneman Jr. 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(2):161-166
Summary Endosperm Balance Number (EBN) is a genetic, dose-dependent crossability system functioning in tuber-bearing Solanum species. Each species has been assigned 1EBN, 2EBN, or 4EBN. Species thus designated cross only within their EBN group. Doubling of chromosome number also doubles the EBN. The ploidy: EBN ratio is not consistent among Solanum species. Some diploids are 2EBN while others are 1EBN. Some tetraploids are 4EBN while others are 2EBN. Species from Mexico typically have EBNs that are one-half of their ploidy [e.g. 2x(1EBN), 4x(2EBN)]. Hybrids of Mexican species and a South American species, 2x(1EBN) S. Commersonii, and its 4x(2EBN) colchicine derivative were made and crossed to 1, 2, and 4EBN standard testers to determine the relationship of the genetic organization of EBN among and within these species. Diploid hybrids crossed only to 1EBN standard testers. Hybrids of 4x(2EBN) S. commersonii and 4x(2EBN) Mexican species crossed almost exclusively to 2EBN standard testers. Complex tetraploid hybrids involving S. commersonii, S. stenophyllidium (a Mexican diploid), and Mexican tetraploids of series Longipedicellata also crossed only to 2EBN testers. The apparent lack of recombination and segregation for EBN in these hybrids indicates that the genomes of the Mexican diploid and tetraploid species carry EBN in a way genetically similar to that of the South American species S. Commersonii.Cooperative investigation of the U.S. Department of Agriculture, Agricultural Research Service and the Wisconsin Experiment Station. Supported in part by the USDA/Cooperative States Research Service Competitive Grant No. 83-CRCR-1-1253 相似文献
6.
Genetic control of Endosperm Balance Number (EBN) in the Solanaceae based on trisomic and mutation analysis. 总被引:3,自引:0,他引:3
The genetic control of Endosperm Balance Number (EBN) was studied using trisomics and induced mutation. In order to induce and detect a change in a factor determining the EBN of the male, pollen from tetraploid Datura was irradiated and used to pollinate diploids. No triploids were produced in over 70 000 fertilizations. At least 70 would have been expected if the deletion of the function of a single gene could change the EBN. An attempt was made to find a particular chromosome that could alter the EBN of the female when it was present as the extra chromosome in 2x + 1 x 4x crosses. In tests of trisomics in both Datura and Solanum (potato) no chromosome could be found that changed the EBN. Therefore, it is concluded that more than one gene and more than one chromosome is involved in determining EBN. Key words : crossing barriers, endosperm, Datura, potato, speciation. 相似文献
7.
M. K. Ehlenfeldt R. E. Hanneman Jr 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,83(3):367-372
Summary Accessions of eight Lycopersicon species and five yellow-flowered Solanum species were used as males in crosses with 2x and 4x L. esculentum to observe seed set and progeny ploidy. Species which failed in crosses to L. esculentum were crossed as males to 2x and 4x L. peruvianum. In cases of low seed set, chromosome counts were undertaken to establish the nature of the progeny. Endosperm Balance Number (EBN) relationships were determined for the crossability groups. Results support the basic concept of an L. esculentum crossability complex and an L. peruvianum crossability complex. Within the L. esculentum complex, all EBNs appear identical with a value of 2. Within the L. peruvianum complex, more variability appears to exist. The EBN values of this group are higher, and may be approximately double those of the L. esculentum complex. The EBN of L. peruvianum var humifusum appears to be somewhat lower than other L. peruvianum types. The EBN values of S. lycopersicoides, S. rickii, S. ochranthum and S. juglandtfolium could not be determined experimentally. Differential aspects of Lycopersicon and tuber-bearing Solanum evolution may be interpreted on the basis of endosperm compatibility.Co-operative investigation of the Vegetable Crops Research Unit, U.S. Department of Agriculture, Agricultural Research Service, and the Wisconsin Agricultural Experiment Station 相似文献
8.
Tumor infiltrating lymphocytes (TIL), especially T-cells, have both prognostic and therapeutic applications. The presence of CD8+ effector T-cells and the ratio of CD8+ cells to FOXP3+ regulatory T-cells have been used as biomarkers of disease prognosis to predict response to various immunotherapies. Blocking the interaction between inhibitory receptors on T-cells and their ligands with therapeutic antibodies including atezolizumab, nivolumab, pembrolizumab and tremelimumab increases the immune response against cancer cells and has shown significant improvement in clinical benefits and survival in several different tumor types. The improved clinical outcome is presumed to be associated with a higher tumor infiltration; therefore, it is thought that more accurate methods for measuring the amount of TIL could assist prognosis and predict treatment response. We have developed and validated quantitative immunohistochemistry (IHC) assays for CD3, CD8 and FOXP3 for immunophenotyping T-lymphocytes in tumor tissue. Various types of formalin fixed, paraffin embedded (FFPE) tumor tissues were immunolabeled with anti-CD3, anti-CD8 and anti-FOXP3 antibodies using an IHC autostainer. The tumor area of stained tissues, including the invasive margin of the tumor, was scored by a pathologist (visual scoring) and by computer-based quantitative image analysis. Two image analysis scores were obtained for the staining of each biomarker: the percent positive cells in the tumor area and positive cells/mm2 tumor area. Comparison of visual vs. image analysis scoring methods using regression analysis showed high correlation and indicated that quantitative image analysis can be used to score the number of positive cells in IHC stained slides. To demonstrate that the IHC assays produce consistent results in normal daily testing, we evaluated the specificity, sensitivity and reproducibility of the IHC assays using both visual and image analysis scoring methods. We found that CD3, CD8 and FOXP3 IHC assays met the fit-for-purpose analytical acceptance validation criteria and that they can be used to support clinical studies. 相似文献
9.
KB Cullberg T Christiansen SK Paulsen JM Bruun SB Pedersen B Richelsen 《Obesity (Silver Spring, Md.)》2013,21(3):454-460
Background:
Vascular growth is a prerequisite for adipose tissue (AT) development and expansion. Some AT cytokines and hormones have effects on vascular development, like vascular endothelial growth factor (VEGF‐A), angiopoietin (ANG‐1), ANG‐2 and angiopoietin‐like protein‐4 (ANGPTL‐4).Methods:
In this study, the independent and combined effects of diet‐induced weight loss and exercise on AT gene expression and proteins levels of those angiogenic factors were investigated. Seventy‐nine obese males and females were randomized to: 1. Exercise‐only (EXO; 12‐weeks exercise without diet‐restriction), 2. Hypocaloric diet (DIO; 8‐weeks very low energy diet (VLED) + 4‐weeks weight maintenance diet) and 3. Hypocaloric diet and exercise (DEX; 8‐weeks VLED + 4‐weeks weight maintenance diet combined with exercise throughout the 12 weeks). Blood samples and fat biopsies were taken before and after the intervention.Results:
Weight loss was 3.5 kg in the EXO group and 12.3 kg in the DIO and DEX groups. VEGF‐A protein was non‐significantly reduced in the weight loss groups. ANG‐1 protein levels were significantly reduced 22‐25% after all three interventions (P < 0.01). The ANG‐1/ANG‐2 ratio was also decreased in all three groups (P < 0.05) by 27‐38%. ANGPTL‐4 was increased in the EXO group (15%, P < 0.05) and 9% (P < 0.05) in the DIO group. VEGF‐A, ANG‐1, and ANGPTL‐4 were all expressed in human AT, but only ANGPTL‐4 was influenced by the interventions.Conclusions:
Our data show that serum VEGF‐A, ANG‐1, ANG‐2, and ANGPTL‐4 levels are influenced by weight changes, indicating the involvement of these factors in the obese state. Moreover, it was found that weight loss generally was associated with a reduced angiogenic activity in the circulation. 相似文献10.
Reza?Yousefi-NooraieEmail author Maureen?Dobbins Alexandra?Marin Robert?Hanneman Lynne?Lohfeld 《Implementation science : IS》2016,10(1):166