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111.
DNA, RNA, protein and heterochromatin changes during embryo development and germination of soybean (Glycine max L.) 总被引:2,自引:0,他引:2
DNA, RNA, protein and heterochromatin were measured cytophotometrically in developing soybean (Glycine max) seeds. The average 2C DNA content for the soybean genome was 2.64 pg. The amounts of nuclear DNA in embryo axes showed no significant change during embryo development, whereas the DNA content in cotyledon nuclei increased significantly from 3.58 pg to 5.49 pg. The number of endopolyploid nuclei increased from 26% to 48% and the DNA content from 4.45 to 5.49 pg after cessation of cell division. The changes in RNA and protein content during embryo development were in general similar to those in DNA content. This can be interpreted that increased DNA levels in soybean cotyledons generated during embryogeny increase the protein synthesizing capacity. During the first 15 days of germination, the number of endopolyploid nuclei in cotyledons declined from 46% to 4%, and this decline is interpreted as DNA degradation providing a ready source of nucleosides and phosphates during early embryo growth. A later decline, however, between 15 and 20 days after germination, was age related similar to leaf senescence, because the percentage of endopolyploid nuclei remained unchanged while the number of non-viable cells increased. In senescing cotyledons, 73% and 80% of RNA and protein but only 20% of DNA were lost, as compared to dormant cotyledons. The heterochromatin (condensed chromatin) measurements indicated that nuclei of metabolically inactive dormant and senescent cotyledon nuclei contained an average of 33% more heterochromatin than nuclei from the green cotyledons of seedlings. 相似文献
112.
Incidence of lysogeny, colicinogeny, and drug resistance in enterobacteria isolated from sewage and from rectum of humans and some domesticated species. 总被引:2,自引:1,他引:1
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Enterobacteria were isolated by streaking swabs of sewage and rectal swabs from human volunteers from domesticated animals. Thirty strains of human origin were identified as Escherichia coli. Out of 1,367 rectal isolates of animal origin, 21% were lysogenic (phi+), 29% were colicinogenic (col+), and 7% were col+ phi+. Out of 85 rectal samples more than 60% harbored variable numbers of col+ or phi+ bacteria. Lysogens harboring homoimmune prophages were detectable in six out of eight human subjects in sequential samples taken at weekly intervals. Chickens in Hong Kong are fed on antibiotic-containing feeds; the avian isolates contained the highest frequency (98%) of drug-resistant bacteria, whereas only 39% of the bovine and 61% of the human isolates were drug resistant. Transmissible drug resistance was demonstrable in sewage isolates and those from animal sources; the highest frequency (58%) of resistance donors was shown by the avian isolates, and the lowest (9%) was shown by the bovine isolates. Unselected marker analysis has shown that a vast majority of multiply resistant donors of diverse origins are able to transmit multiple resistance. 相似文献
113.
Age-related DNA changes in soybean ( Glycine max L. cv. Ransom) cotyledon nuclei were investigated by Feulgen cytophotometry and cloned DNA probes. The amount of nuclear DNA in 17-day-old senescing cotyledons was 23% lower than that of 5-day-old young cotyledons. In order to understand the nature of senescence-related DNA loss, fragments of repetitive DNA from young cotyledons were cloned into Escherichia coli HB101 cells by DNA recombination. The cloned DNA probed changes in specific repeated nucleotide sequences in senescing cotyledons. The colony hybridization between cloned DNA and [32 P]-labeled total DNA from 5- and 17-day cotyledons indicated loss of specific repeated sequences. The selected sequences of repeated DNA further showed a loss in their copy numbers. The study suggested that some repetitive DNA sequences were degraded selectively in the genome of senescing cotyledons. 相似文献
114.
D. S. Virk A. S. Khehra Parminder S. Virk B. S. Dhillon 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,69(3):325-328
Summary For studying the inheritance of metric traits, diallel cross and factorial mating designs are commonly used. Since factorial mating design is less restrictive in crossing plans, the genetic information drawn from it was compared with that from a diallel cross. The comparison was made using graphical, genetic components and combining ability analyses for grain yield, grain weight and spike length in a field experiment of bread wheat (Triticum aestivum L.). Analyses were made on a nine parent diallel cross and a 4 × 5 factorial mating design which was sampled from the diallel cross. In general, there was a high degree of agreement between the results obtained from factorial mating design and diallel cross analyses showing thereby that the former provides almost equivalent genetic information to the latter. 相似文献
115.
The ether soluble extracts from stem and root tissues of malformed seedlings of mango showed four malformin-like substances on chromatograms in the corn root curvature test at Rf 0–0.1 (M1), 0.1–0.2 (M2), 0.8–0.9 (M9) and 0.9–1.0 (M10). M10 was identified as a malformin A-like substance(s). Stems and roots of malformed seedlings contained high levels of malformin A-like substance(s) (42.0 μg/g and 41.0 μg/g) respectively, which were absent in stems and roots of healthy seedlings. 相似文献
116.
Influence of Varied Phosphorus Supply on Growth and Xylem Sap Cytokinin Level of Sycamore (Platanus occidentalis L.) Seedlings 总被引:1,自引:1,他引:0
Dhillon SS 《Plant physiology》1978,61(4):521-524
Effects of varying levels of phosphorus (P) on sycamore (Platanus occidentalis L.) growth and on the endogenous cytokinin levels in the xylem sap were tested. The seedlings were grown in aerated nutrient solutions in the greenhouse. Photoperiod was held constant at 16 hours. Four P concentrations, 0.02, 0.10, 0.50, and 2 mm, were used. There were no P deficiency symptoms even at the lowest P concentration. The maximum growth occurred in seedlings grown in 0.10 mm P. The greatest dry matter yield as well as stem height, stem diameter, and leaf area were produced at 0.10 or 0.50 mm P. The amount of cytokinin in xylem sap for each harvest during P nutrition followed closely the dry matter values, stem height, stem diameter, and leaf area. 相似文献
117.
E K Dhillon T S Dhillon Y Y Lam A H Tsang 《Applied and environmental microbiology》1980,39(5):1046-1053
Temperate coliphages were recovered from sewage, mammalian feces, and lysogenic strains of Escherichia coli. A total of 32 phages of independent origin were divided into six groups by applying the criteria of host range, antigenic homology, and the ultraviolet inducibility of the prophage. The demonstration of genetic interactions in some cases has confirmed the classification scheme. Nine phages were assigned to the P2 family and 19 to the lambda family. The remaining four isolates may represent some novel phylogenetic types. Phages recovered from the lysogenic strains of E. coli were all found to be P2 related, whereas a majority of the phages recovered as cell-free plaque-forming units were assignable to the lambda family. It is proposed that the biological attributes of the phages belonging to the two principal families are reflected in the distribution patterns observed. The virions of phage HK256 show multiple tail fibers and may thus represent a "new" virion form among the temperate coliphages. 相似文献
118.
Toru Nagasawa Gurdev Singh Dhillon Takafumi Ishii Hideaki Yamada 《Journal of biotechnology》1985,2(6):365-377
The regulatory properties of serine-O-transacetylase and O-acetylserine sulfhydrylase have been investigated with 3-chloro-l-alanine resistant Bacillus sphaericus L-118. The enhancement of O-acetylserine sulfhydrylase formation by 3-chloro-l-alanine was observed and this effect was counteracted by corepressor l-cysteine. O-Acetylserine sulfhydrylase occurring in B. sphaericus L-118 can catalyse β-replacement reaction of 3-chloro-l-alanine in the presence of a high concentration of sodium hydrosulfide to form l-cysteine. The optimal reaction conditions for l-cysteine production were studied using resting cells. Under optimal conditions, about 80% of the added 3-chloro-l-alanine could be converted to l-cysteine. The highest yield achieved was 70 mg of l-cysteine per 1.0 ml of the reaction mixture. 相似文献
119.
120.