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11.
Summary We have examined DNA restriction fragment length polymorphisms (RFLP) of the Ha-ras-1 gene in DNA from 118 lung cancer patients and 123 unaffected controls. When DNA samples were digested with MspI/ HpaII restriction endonucleases. Southern blot analysis demonstrated 4 common, 4 intermediate and 7 different rare alleles in the combined population after hybridization to the pGDa1 probe. Six of the rare alleles were unique for the lung cancer group and 1 rare allele for the control group. The frequency of rare alleles in lung cancer patients (10/236) was significantly different (P<0.01) from the control group (1/246). The lung cancer group also had a significantly lower frequency of the common 2.57 kb fragment than the controls (P<0.02). The results thus indicate that Ha-ras genotyping may be of value in lung cancer risk assessment.  相似文献   
12.
Schrankia nuttalii flowers through late spring on the tallgrass prairie. Although each stem produces an average of 26 capitate inflorescences only 12% of those inflorescences will open each day to disperse and receive polyads. Each inflorescence may live up to 48 hours but anthers abscise by late afternoon on the first day and the filaments change color and lose their scent. The 78–93 florets comprising each inflorescence open synchronously before dawn or during early morning hours. First day inflorescences ofS. nuttallii are herkogamous and fragrant. They are nectarless. Bombyliid flies and male bees are infrequent floral foragers so the major pollinators include female bees representing five families;Anthophoridae, Apidae, Colletidae, Halictidae, andMegachilidae. All foraging insects ignore second day inflorescences although stigmas are still receptive. Although 97% of all bees collected onS. nuttallii carrySchrankia polyads in their scopae or corbiculae 59% also carry the pollen/pollinaria of one or more coblooming angiosperms. At least 98% of all bees carrying mixed pollen loads incorporate the pollen/pollinaria of one or more nectariferous taxa (e.g.Asclepias spp.,Asteraceae, Convolvulaceae, Delphinium spec., etc.). Species of halictid bees are more likely to carry pure loads ofS. nuttallii polyads (70%) than bees of the four remaining families. Due to the nectarless florets and high degree of polylectic foraging bee-pollination inS. nuttallii converges more closely with the pollination systems of some AustralianAcacia spp. than with most other xeric/tropical genera of mimosoids studied in the western hemisphere.  相似文献   
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Protoplasts were isolated from anther-derived suspension cultures of commercial wheat (Triticum aestivum L. cv. Chris). The protoplasts were released enzymatically and isolated by centrifugation on a sucrose cushion. The isolated protoplasts were initially cultured in a liquid medium in the dark. Numerous microcalli were produced under these conditions, some of which differentiated into globular embryos. Upon transfer to a solid medium and exposure to 16h/8h light/dark cycle, the protocalli proliferated and many of the somatic embryos matured. Complete plantlets were obtained and maintained in sterile culture.Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid - MES 2-[N-morpholino] ethanesulfonic acid  相似文献   
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Abstract Extended survival of Legionella pneumophila , using both a clinical and an environmental isolate, was studied in drinking water, creek water, and estuarine water microcosms. Legionella populations were monitored by acridine orange direct counts (AODC) and viable count on buffered charcoal yeast extract agar amended with alpha-ketoglutarate (BCYEα). Initial colony counts of the clinical isolate in drinking and creek water microcosms were 2 × 108 cfu/ml and, after incubation for 1.5 years, the plate counts decreased to 3 × 106 cfu/ml. The AODC counts, however, did not change significantly. The clinical isolate in estuarine water decreased in plate counts to 102 (cfu/ml) over the same period. After incubation for 1.5 years at 15°C in the microcosms, Legionella plate counts of creek and drinking water decreased by two logs. Direct microscopic examination of aliquots removed from all microcosms revealed the presence of small bacilli, large bacilli and rare filamentous cells. The environmental isolate demonstrated only one colony morphology upon culture on BCYEα. Interestingly, after four months incubation in the microcosm, upon plating the clinical isolate on BCYEα, two distinct colony types were evident. Examination by immunofluorescent staining employing a monoclonal antibody against L. pneumophila revealed both bacillus and filamentous forms. The total cellular proteins of both morphotypes were examined by sodium dodecyl sulfate polyacrylyamide gel electrophoresis (SDS-PAGE), demonstrating identical protein patterns. Those Legionella cells remaining culturable during 1.5 years of incubation grew rapidly when transferred to BCYEα. Incubation was continued and it was found that some strains of L. pneumophila serogroup 1 can remain viable for longer than 2.4 years under low-nutrient conditions.  相似文献   
17.
6′-O-(E-4-hydroxycinnamoyl) Desglucouzarin, the first cardenolide containing a cinnamoyl ester moiety, has been isolated from the ethanolic extract of the milkweed, Asclepias asperula. In addition, five known cardenolides were isolated and identified from A. asperula and A. viridis.  相似文献   
18.
The effects of humic substances on in vitro culture of Golden Delicious apple are reported. Potassium humate (KH) when used in proliferation showed a negative interaction with BA while it enhanced rooting when IBA was not present in the culture medium. In the presence of IBA, KH increased root number and reduced root growth. The highest concentration tested, 500 mg l-1, caused a drastic reduction in root system development. 50 mg l-1 KH hastened rooting and plants grew more rapidly when transferred to soil.  相似文献   
19.
DEAE-cellulose column chromatography of Neurospora crassa soluble mycelial extracts leads to the resolution of three major protein kinase activity peaks designated PKI, PKII, and PKIII.PKII activity is stimulated by Ca2+ and Neurospora or brain calmodulin. Maximal stimulation was observed at 2 µM-free Ca2+ and 1 µg/ml of the modulator. The stimulatory effect of the Ca2+-calmodulin complex was blocked by EGTA and by some calmodulin antagonists such as phenothiazine drugs or compound 48/80.PKII phosphorylates different proteins, among which histone II-A at a low concentration and CDPKS, the synthetic peptide specific for Ca2+-calmodulin dependent protein kinases, are the best substrates. Some phosphorylation can be detected in the absence of any exogenous acceptor. PKII activity assayed in the presence of histone II-A or in the absence of exogenous phosphate acceptor (autophosphorylation) co-elute in a DEAE-cellulose column at 0.28 M NaCl. As result of the autophosphorylation reaction of the purified enzyme a main phosphorylated component of 70 kDa was resolved by SDS-polyacrylamide gel electrophoresis. It is possible that this component is an active part of this enzyme.  相似文献   
20.
Summary In addition to bovine pancreatic trypsin inhibitor (BPTI), three BPTI-related molecular forms (isoinhibitors I, II and III) were isolated from bovine lung by affinity chromatography on immobilized trypsin and subsequently purified by Fast Protein Liquid Chromatography. These inhibitors are identical to the isoinhibitors previously isolated from bovine spleen. Their localization in bovine lung was studied by immunohistochemical techniques, using two different immunoglobulin preparations, selectively recognizing BPTI or the other molecular forms.BPTI-related immunoreactivity was found to be restricted to isolated cells, often identified as mast cells by Toluidine Blue staining. In contrast, isoinhibitor-related immunoreactivity, which also occurs in the mast cells, is present in a number of other cell types. These types include: (i) the smooth muscle cells of different calibre vessels, (ii) the ciliated cells of the bronchial epithelium and the related mucus, and (iii) many cells at alveolar level.Comparison of these data with previous results obtained for bovine spleen suggest multiple physiological roles for these inhibitors.  相似文献   
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