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41.
Branch internodes of mature plants and stem internodes of seedlings of Fortunella hindsii flowered in vitro on half-strength MT (Murashige and Tucker 1969) basal medium supplemented with benzyladenine, adenine, 6---dimethylallylaminopurine and kinetin. The highest percentage of flowering was achieved with explants originating from branch internodes of flowering plants close to the apex on half-strength MT basal medium containing 5% sucrose and 0.01 mg 1–1 BA in light. Exposure to darkness for more than 3 weeks followed by re-exposure to light reduced flowering. Flowering required a 4-day exposure to BA, but shoot formation could be initiated even without exposure to BA. First branch internode segments on MT basal medium containing 5% sucrose were prolific in flower (85%) production. The sucrose treatment affected the flower bud size distribution. There were about 13 flower buds per culture in the largest size category (>5 mm). 相似文献
42.
Drought is an important environmental factor that can affect rhizobial competition and N2 fixation. Three alfalfa (Medicago sativa L. and M. falcata L.) accessions were grown in pots containing soil from an irrigated (Soil 1) and a dryland (Soil 2) alfalfa field in northern
Utah, USA. Mutants of three strains of Rhizobium meliloti Dang. from Pakistan (UL 136, UL 210, and UL 222) and a commercial rhizobial strain 102F51a were developed with various levels
of resistance to streptomycin. Seeds inoculated with these individual streptomycin-resistant mutants were sown in the two
soils containing naturalized rhizobial populations. Soils in the pots were maintained at −0.03, −0.5, and −1.0 MPa. After
10 weeks, plants were harvested and nodule isolates were cultured on agar medium with and without streptomycin to determine
nodule occupancy (proportion of the nodules occupied by introduced rhizobial strains). Number of nodules, nodule occupancy,
total plant dry weight, and shoot N were higher for Soil 1 than Soil 2. Number of nodules, plant dry weight, and shoot N decreased
as drought increased from −0.03 to −1.0 MPa in the three alfalfa accessions. Rhizobial strains UL 136 and UL 222 were competitive
with naturalized alfalfa rhizobia and were effective at symbiotic N2 fixation under drought. These results suggest that nodulation, growth, and N2 fixation in alfalfa can be improved by inoculation with competitive and drought-tolerant rhizobia and may be one economically
feasible way to increase alfalfa production in water-limited environments.
Joint contribution from USDA-ARS and the Utah Agric. Exp. Sta., Utah State Univ., Logan, UT 84322-4810, USA. Journal Paper
No. 4931.
Joint contribution from USDA-ARS and the Utah Agric. Exp. Sta., Utah State Univ., Logan, UT 84322-4810, USA. Journal Paper
No. 4931. 相似文献
43.
Globoid cell leukodystrophy, or Krabbe disease, is a severe, autosomal recessive disorder resulting from a deficiency of galactocerebrosidase (GALC) activity. GALC is responsible for the lysosomal catabolism of certain galactolipids, including galactosylceramide and psychosine. In addition to the human patients, there are several naturally occurring animal models for this disease, including the twitcher mouse, West Highland White terriers (WHWT), and Cairn terriers. All species have deficient GALC activity and have the characteristic pathological findings in the nervous system. We now describe the cloning of the canine GALC cDNA and the identification of the disease-causing mutation in both terrier breeds. The 2007-bp open reading frame is 88% identical to that in human, and the deduced amino acid sequence is about 90% identical. However, the 3′-untranslated region is about 1 kb shorter than that in the human. Two nucleotide changes were found in affected dogs, an A to C transversion at cDNA position 473 (Y158S) and a C to T transition at position 1915 (P639S). Expression studies in COS-1 cells demonstrated that the A to C change at 473 is the disease-causing mutation. A rapid test for the identification of the genotype at that position has been developed, and over 100 WHWT and Cairn terriers have been screened. This will allow breeders to mate their dogs selectively and will permit the establishment of a colony of dogs for use in therapy trials. 相似文献
44.
45.
H. A. H. Hasan 《Folia microbiologica》1994,39(4):365-367
Miconazole (MC), an effective drug used in medicine as a topical broad-spectrum antifungal agents for treating tinea, aspergilloses
and candidoses, was used for studying its effect on sterols, ochratoxin A and B biosynthesis byAspergillus ochraceus in vitro. Sterol biosynthesis and production of ochratoxin A and B were inhibited by MC when added into the culture medium together
with the inoculum. MC, addition 2 d after culture inoculation, inhibited sterol biosynthesis after 5, 9 and 14 d, ochratoxin
A production after 5 and 9 d and ochratoxin B production after 9 d of incubation. However, at 10, 50 and 100 ppm concentrations
it induced a significant accumulation of both toxins after 14 d of incubation. 相似文献
46.
Endogenous gibberellins (GAs) were extracted and purified from apical buds of Eucalyptus nitens (Deane and Maid.) Maid. and the cambial region of E. globulus (Labill.). then analysed by capillary gas chromatography-mass spectrometry. GA1 GA19 GA20 and GA29 were identified by full scan mass spectra. Kovats retention indices and high resolution selected ion monitoring. Using deuterated internal standards. GA1 . GA19 . GA20 and putative GA29 and GA53 were quantified in the apical buds, while GA4 . GA8 . GA9 and GA44 were shown to be either absent or present at very low levels. From the cambial region. GA1 and GA20 were quantified at levels of 0.30 ng (g fresh weight)-1 and 8.8 ng (g fresh weight)-1 respectively. These data suggest that the early 13-hydroxylation pathway is the dominant pathway for GA biosynthesis in Eucalyptus . 相似文献
47.
Mohammad B. Rashid Katsuhiko Shirahige Naotake Ogasawara Hiroshi Yoshikawa 《Gene》1994,150(2):213-220
We have analyzed the relationship between autonomously replicating sequence (ARS) structure and function for three ARS (ARS605, ARS607 and ARS609) from chromosome VI of Saccharomyces cerevisiae by systematic XhoI-linker mutation in the ARS consensus sequence (ACS) and flanking sequences. All mutations that encroached upon the ACS destroyed ARS activity. DNA sequences stimulative for ARS function were identified on either side of the ACS of ARS605 and only on the 3'-side of the ACS of ARS607. In ARS609, however, no such stimulative sequences were observed. Base substitutions complementary to the wild-type sequence of those stimulative regions, in ARS605 and ARS607, that did not change the AG of unwinding nor affected ARS activity suggests that these regions have, at least, a function as DNA-unwinding elements (DUE). ARS605, ARS607 and ARS609 DNA are of low AG value and showed hypersensitivity to single-strand-specific nuclease when inserted in negatively supercoiled plasmid. Linker mutations inhibitory for ARS activity (5L11 and 7L14) also caused significant changes in local nucleotide (nt) sensitivity within the ACS and its adjoining regions. Complementary base substitutions, however, did not affect these changes in local nt sensitivity. These results imply that the stimulative regions flanking the ACS are necessary to produce an optimum conformation around the ACS which may be important for full ARS activity. 相似文献
48.
49.
H. A. H. Hasan 《Folia microbiologica》1993,38(4):295-298
The effect of fungicides on the production of aflatoxin byAspergillus flavus IMI 89717, diacetoxyscirpenol and zearalenone byFusarium graminearum was studied. In a yeast extract - sucrose medium, dicloran, iprodione and vinclozolin fungicides significantly inhibited
mycelial growth ofA. flavus at 250 ppm and significantly decreased aflatoxin production at 100, 250 and 500 ppm, respectively. In potato — dextrose broth,
these fungicides diminished the mycelial growth ofF. graminearum and production of diacetoxyscirpenol and zearalenone at 100 ppm. Sensitivity of toxigenic mycelia to fungicides increased
approximately five-fold in a yeast extract-starch medium with an appreciable reduction in sugar uptake andα-amylase activity. 相似文献
50.
Mohsen A. F. El-Hazmi Hassan M. Bahakim Arjumand S. Warsy Abdulkarim Al-Momen Abdullah Al-Wazzan Ibrahim Al-Fawwaz Sameer Huraib Mohammad Harakati 《Molecular and cellular biochemistry》1993,124(1):17-22
Sickle cell anaemia (SCA) exhibits significant variations in clinical presentation in different populations for which several genetic factors including SCA-associated -and -thalassaemias, G-6-PD deficiency and elevated Hb F level have been implicated as possible ameliorating factors. Saudi Arabia is unique in that mild and severe forms of the disease occur at a high frequency. We investigated the G/A ratio and Hb F level and correlated these values with the severity of SCA. The results showed that Hb F level varies significantly in both groups of patients with no evident correlation with the mild clinical manifestations. However, G/A ratio correlated significantly with the disease severity where a high ratio was observed in patients with the mild and a low ratio in patients with the severe disease. The results are evaluated and discussed in the light of correlation studies and regression analysis. 相似文献