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911.
912.
913.
bor1-1, an Arabidopsis thaliana mutant that requires a high level of boron. 总被引:3,自引:0,他引:3
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K Noguchi M Yasumori T Imai S Naito T Matsunaga H Oda H Hayashi M Chino T Fujiwara 《Plant physiology》1997,115(3):901-906
bor1-1 (high boron requiring), an Arabidopsis thaliana mutant that requires a high level of B, was isolated. When the B concentration in the medium was reduced to 3 microM, the expansion of rosette leaves was severely affected in bor1-1 but not in wild-type plants. In a medium containing 30 microM B the mutant grew normally but showed female sterility, whereas the wild type was able to set seeds. These defects of the bor1-1 mutant were not detected with supplementation of 100 microM B. In vivo concentrations of B in bor1-1 mutants were lower than those of the wild type, especially in the inflorescence stems. Tracer experiments using 10B suggested that the mutant has defects in uptake and/or translocation of B. The mutation was mapped on the lower arm of chromosome 2. 相似文献
914.
Forty-six immunoglobulin VH gene sequences of rainbow trout were compiled to analyze the extent of variations and the frequency of nucleotide changes
in CDRs and FRs. The results show that the frequency of nonsynonymous (amino acid replacing) changes (Ka) are on average 4.9
times higher in complementarity determining regions (CDRs) than in FRs, thus contributing more diversity in CDRs. Unexpectedly,
however, the frequency of synonymous (silent) changes (Ks) show the same tendency: it was 5.3 times higher in CDRs than in
framework regions (FRs). The distribution of Ks/Ka ratios of each comparison shows no segregation between CDRs and FRs. The
same analysis applied to five germline VH genes of Heterodontus francisci shows the same result as was found with the rainbow trout. In contrast, the results from mouse data show that, while the
CDR/FR ratio for Ka is much higher (7.4), the CDR/FR ratio for Ks is only slightly higher (1.8). The distribution of Ks/Ka
ratios in mouse indicates clear segregation between CDRs and FRs. This suggests that CDR germline diversity is largely generated
by gene conversion in VHs of lower vertebrates such as rainbow trout or shark. This mechanism might be advantageous to lower vertebrates in generating
V gene diversity faster than other mechanisms such as point mutation and selection.
Received: 10 July 1996 / Revised: 9 September 1996 相似文献
915.
Hiroaki Sudo Akiyo Yamada Noriyuki Nakamura Tadashi Matsunaga 《Biotechnology letters》1997,19(8):783-786
Among 8 strains of typical marine and freshwater photosynthetic bacteria, a Chromatium sp., which is known to flocculate upon the addition of seawater, had the highest intracellular phosphorus content of 0.865 mmol P/mg dry wt with a ratio of polyphosphate to phosphate (poly-Pi/Pi) of 2.14. Intracellular phosphorus content increased withincreasing NaCl concentration up to 260 mM. The poly-Pi/Pi value was also the highest in the medium containing 260 mM NaCl. Sodium cation in seawater enhanced intracellular phosphorus accumulation in this bacterium. 相似文献
916.
Toshio Aoki Hideki Matsumoto Youichi Asako Yuji Matsunaga Koichiro Shimomura 《Plant cell reports》1997,16(5):282-286
Hairy root cultures ofAtropabelladonna were established by transformation withAgrobacterium rhizogenes 15834. Five clones of them were employed to study the production of hyoscyamine, the main constituent of the plant, together with other tropane alkaloids. The growth and alkaloid production of each clone were differently affected by basal liquid culture media tested. The transgenic plants regenerated from each clone of the hairy roots had different phenotypes and diverse alkaloid productivity both in the cultured condition and in productivitiy both in the cultured condition and in hydroponics.Abbreviations ANOVA
analysis of variance
- B5 medium
Gamborg B5 medium
- BA
N6-benzyladenine
- B.S.
Balanced Solution
- dw
dry weight
- EC
electric conductivity
- fw
fresh weight
- GC/MS
gas chromatography-mass spectrometry
- HPLC
high performance liquid chromatography
- MS medium
Murashige and Skoog medium
- NAA
naphthalene-l-acetic acid
- PCR
polymerase chain reaction
- SDS
sodium dodecyl sulfate
- TMS
trimethylsilyl
- WP medium
Woody Plant medium 相似文献
917.
A vector, pUK318, was constructed to allow the expression of foreign genes in the marine photosynthetic bacterium Rhodobacter sp. NKPB 0021. This strain has been cured of its two endogenous plasmids. pUK318 consists of a 2.3-kb PstI-BamHI restriction fragment, containing a marine Rhodobacter plasmid replication region, cloned into pUC18. This fragment was derived from plasmid pRD31, a 3.1-kb endogenous plasmid purified from the marine strain Rhodobacter sp. NKPB 043402. A kanamycin resistance gene from Tn903 was cloned into the PstI restriction site to provide antibiotic selection. pUK318 was transferred to Rhodobacter sp. NKPB 0021 by transformation, and efficiencies of 7.2 x 10(-5) were obtained. Furthermore, pUK318 was stably maintained when transformants were grown either heterotrophically or photosynthetically in the absence of antibiotics. pUK318 was used to express the Escherichia coli chloramphenicol acetyl transferase (CAT) gene in Rb. NKPB 0021. Transformants expressed a maximum CAT activity of 1.12 mmol/min/g dry cells. In addition, the DNA region essential for pUK318 replication in Rb. NKPB 0021 was localized to a 1.36-kb HincII-PstI fragment. This is the first report of a plasmid vector containing a marine Rhodobacter-specific replicon that allows stable expression of foreign genes in the absence of antibiotic selection. 相似文献
918.
919.
920.
Koji Sode Masahiro Tatara Shigeo Ogawa Tadashi Matsunaga 《FEMS microbiology letters》1992,99(1):73-78
Clinical isolate of Vibrio mimicus were examined for production of cell-associated hemagglutinin (HA) and pili and for adherence to formalin-fixed human intestinal mucosa. V. mimicus grown on CFA agar for 3 h at 37 degrees C possessed HA and adhered better to the mucus layer than to the epithelial cell surface. A significant correlation was found between the HA titers and adherence ability to the epithelial cell surface of villi (P less than 0.05); adherence to the ileal lymphoid follicle-associated epithelium occurred at higher levels. In contrast, V. mimicus grown on CFA agar for 20 h at 37 degrees C exhibited lower levels of HA and reduced adherence ability. The production of pili was more pronounced after 20 h of incubation than after 3 h of incubation. In comparison with V. cholerae 01 and V. cholerae non-01 cultured under similar conditions, V. mimicus showed inferior adherence, but with similar HA production or piliation. 相似文献