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21.
A marked increase in the isolation of Group B streptococci from patients in the University Hospital, Saskatoon, has been noted over the past four years, and no change in technical methods has been found to explain this increase. Group B streptococci have been isolated from 242 patients, in 53 of whom the streptococcus was considered the cause of the infection. Infections occurred predominantly in the urinary tract, female genital tract and upper respiratory tract. There was a low incidence of infections in newborn infants, and only four infections were in patients under 1 year old. Infections were more frequent in women than men and in patients over 40 years of age. No particular affinity of Group B streptococci for diabetics was demonstrated. 相似文献
22.
Conclusions Incubation of competent cells ofB. subtilis with a DNA-like subviral entity from vaccinia virus leads to the formation of complete vaccinia virus in the bacteria. The significance of this finding in regard to the concept of a universal genetic code is discussed.With 2 Figures in the TextA preliminary report of these results was presented at the XI. International Congress of Genetics in The Hague, September, 1963.Habilitandenstipendiat 1962/63 of Deutsche Forschungsgemeinschaft. 相似文献
23.
C. A. Gibson G. B. Landerkin Pamela M. Morse 《Applied and environmental microbiology》1966,14(4):665-669
Three single-strain cultures, Streptococcus lactis C2, S. cremoris R1, and S. diacetilactis DRC2, were frozen and stored in skim milk, in skim milk containing apple juice, and in skim milk containing one of the following additives: glycerol (10%, v/v), dimethyl sulfoxide (10%, v/v), l-malic acid (0.5 and 2.0%, w/v), acetamide (0.5 and 2.0%, w/v), or succinimide (0.5 and 2.0%, w/v). Cultures were frozen and stored at -23.3 C, frozen and stored at -196 C in liquid nitrogen, or frozen at -196 C and stored at -23.3 C. Cultures frozen and stored at -196 C in liquid nitrogen gave the greatest recovery of viable cells. The number of cells surviving after storage at -23.3 C was greater when the cells had been frozen in liquid N2 than when they had been frozen at -23.3 C. All strains stored at -23.3 C showed a decrease in numbers of surviving cells; additives, particularly l-malic acid and apple juice, were advantageous in preserving the viability of the S. lactis C2 and S. cremoris R1 strains, but had little or no effect on the survival of S. diacetilactis DRC2. l-Malic acid and apple juice stimulated acid production for all cultures in activity tests following incubation after thawing, whereas glycerol and dimethyl sulfoxide retarded its development. 相似文献
24.
Yuhsi Matuq Pamela S. Adams Nozomu Nishi Hidetaro Yasumitsu John W. Crabb Robert J. Matusik Wallace L. McKeehan 《In vitro cellular & developmental biology. Plant》1989,25(6):581-584
Summary Rat prostate extracts contain an abundant 20–22 kilodalton heparin-binding protein with near identical chromatographic properties,
but only 0.2–1% of the mitogenic activity, of bovine brain heparin-binding growth factor-1 (acidic fibroblast growth factor).
Amino terminal amino acid sequence (met-met-thr-asp-lys-asn-leu-lys-lys-lys-ile-glu-gly-asn-trp-arg-thr-val-tyr-leu-ala-ala-ser-?-val-glu-lys-ile-asn-glu-gly-ser-pro)
and immunochemical analysis revealed that the protein is identical to the androgen-dependent protein “probasin”.
This work was supported in part by NCI grant CA37589 (W. L. M., J. W. C.) and the Medical Research Council of Canada (R. J.
M.). 相似文献
25.
Gary Gibson Pamela Nielsen Victoria Mykytyn Ken Carlson John Blass 《Neurochemical research》1989,14(1):17-24
To further elucidate the molecular basis of the selective damage to various brain regions by thiamin deficiency, changes in enzymatic activities were compared to carbohydrate flux through various pathways from vulnerable (mammillary bodies and inferior colliculi) and nonvulnerable (cochlear nuclei) regions after 11 or 14 days of pyrithiamin-induced thiamin deficiency. After 11 days,large decreases (–43 to –59%) in transketolase (TK) occurred in all 3 regions; 2-ketoglutarate dehydrogenase (KGDHC) declined (–45%), but only in mammillary bodies; pyruvate dehydrogenase (PDHC) was unaffected. By day 14, TK remained reduced by 58%–66%; KGDHC was now reduced in all regions (–48 to –55%); PDHC was also reduced (–32%), but only in the mammillary bodies. Thus, the enzyme changes did not parallel the pathological vulnerability of these regions to thiamin deficiency.14CO2 production from14C-glucose labeled in various positions was utilized to assess metabolic flux. After 14 days, CO2 production in the vulnerable regions declined severely (–46 to 70%) and approximately twice as much as those in the cochlear nucleus. Also by day 14, the ratio of enzymatic activity to metabolic flux increased as much as 56% in the vulnerable regions, but decreased 18 to 30% in the cochlear nuclei. These differences reflect a greater decrease in flux than enzyme activities in the two vulnerable regions. Thus, selective cellular responses to thiamin deficiency can be demonstrated ex vivo, and these changes can be directly related to alterations in metabolic flux. Since they cannot be related to enzymatic alterations in the three regions, factors other than decreases in the activity of these TPP-dependent enzymes must underlie selective vulnerability in this model of thiamin deficiency.Abbreviations KGDHC
2-ketoglutarate dehydrogenase complex EC 1.2.4.2., EC 2.3.1.61, EC 1.6.4.3.
- PDHC
pyruvate dehydrogenase complex EC 1.2.4.2., EC 2.3.1.12, EC 1.6.4.3
- TK
transketolase (EC 2.2.1.1)
- TPP
thiamin pyrophosphate 相似文献
26.
Pamela Matson 《Oecologia》1990,85(2):241-246
Summary Plant nutrient status and physiological processes were examined in relation to soil nutrient characteristics under individuals of five species colonizing a young cinder deposit in Hawaii Volcanoes National Park. Two exotic species, Buddeleja asiatica and Myrica faya, had high photosynthetic rates and high nitrogen concentrations and relatively easily decomposed leaves; soils under them had high concentrations of nitrogen, cations, and organic matter and high rates of net nitrogen mineralization. At the other extreme, the natives Metrosideros polymorpha and Vaccinium reticulatum had low plant concentrations and photosynthetic rates, and low concentrations and turnover rates of N in the soil. Thus, a strong correlation exists between soil processes and plant processes, suggesting a positive feedback cycle. 相似文献
27.
Transformed plants with elevated levels of chloroplastic SOD are not more resistant to superoxide toxicity 总被引:29,自引:0,他引:29
The petunia nuclear gene which encodes the chloroplast isozyme of superoxide dismutase, SOD-1, has been fused with an efficient rbcS promoter fragment and 3 flanking region and introduced into tobacco and tomato cells. Transformed plants carrying this chimeric gene have up to 50-fold the levels of SOD-1 which occur in wild-type plants. However, tobacco plants with 30-to 50-fold the normal SOD-1 activity do not exhibit resistance to the light-activated herbicide paraquat. Similarly, tomato plants with 2-to 4-fold increases in SOD-1 do not exhibit tolerance to photoinhibitory conditions known to increase superoxide levels (high light, low temperatures and low CO2 concentrations). Our data indicate that increasing the chloroplastic SOD level in a plant cell is not sufficient to reduce the toxicity of superoxide. 相似文献
28.
Free amino acid levels and the regulation of nitrate uptake in maize cell suspension cultures 总被引:4,自引:2,他引:2
The ability of individual amino acids to regulate nitrate uptakeand induction was studied in a Zea mays embryo cell line grownin suspension culture. The maize cells exhibited a marked preferencefor absorbing amino acids over nitrate when both were presentin culture medium. The addition of an individual amino acid(2 mM glutamine, glycine, aspartic acid, or arginine) to theculture medium with 1 mM nitrate completely inhibited nitrateuptake and resulted in a cycle of low levels of nitrate influxfollowed by efflux to the growth medium. Glutamine was readilyabsorbed by the cells and was particularly effective in supportingoptimum cell growth in the absence of an inorganic nitrogensource as compared to the three other amino acids evaluated.However, neither glutamine nor any of the remaining 19 proteinaceousamino acids appeared to be solely responsible for regulationof nitrate uptake and induction. The ability of amino acidsto regulate nitrate uptake and assimilation appears to be morerelated to their overall levels in the cell rather than to anaccumulation of a specific amino acid. Key words: Amino acids, nitrate uptake, maize, regulation, cell suspension culture 相似文献
29.
Elizabeth A. Kingsley Teresa E. Carter Kevin D. Barrow Pamela J. Russell 《Cancer immunology, immunotherapy : CII》1996,41(6):348-354
A monoclonal antibody, BLCA-8, was raised against the human bladder cancer cell line, UCRU-BL-17CL. By flow cytometry and immunoperoxidase staining, this antibody was found to possess high specificity for bladder tumours, some reactivity with fetal tissues, and no reactivity with normal bladder, or any normal or malignant tissue. This high specificity and the stability of the antigen to the urinary environment suggest that BLCA-8 may have potential for use as an anti-bladder-cancer therapeutic agent. By thin-layer chromatography and autoradiography, BLCA-8 was found to bind four components within the neutral lipid fraction of a bladder cancer cell line, UCRU-BL-17/23. These components hadR
F values of 0.22, 0.16/0.15 (doublet), 0.12 and 0.08, and migrated below globoside, indicating the presence of more than four sugars. By enzyme-linked immunosorbant assay and thin-layer chromatography it was found that the binding of BLCA-8 to the lipid extract was increased by both mild alkaline hydrolysis and enzymatic treatments, indicating that adjacent phospholipids and glycolipids interfere with the accessibility of the antibody-binding site. Full biochemical characterisation of the BLCA-8 antigen is currently underway. 相似文献
30.
Gregory M. Plunkett Douglas E. Soltis Pamela S. Soltis 《American journal of botany》1996,83(4):499-515
The two families of the order Apiales (Apiaceae and Araliaceae) represent a classic example of the difficulty in understanding evolutionary relationships between tropical-temperate family pairs. In Apiales, this problem is further compounded by phylogenetic confusion at almost every taxonomic level, including ordinal, interfamilial, and infrafamilial, due largely to difficulties in understanding trends in morphological evolution. Phylogenetic analyses of rbcL sequences were employed to resolve relationships at the ordinal and familial levels. The results of the ordinal analysis confirm the placement of Apiales in an expanded subclass Asteridae as the sister group to Pittosporaceae, and refute the traditional alliance of Apiales with Cornales and Rosidae. This study has also resolved relationships of a number of enigmatic genera, suggesting, for example, that Melanophylla, Aralidium, Griselinia, and Toricellia are close relatives of Apiales. Clarification of phylogenetic relationships has concomitantly provided insights into trends of morphological evolution, and suggests that the ancestral apialean taxon was probably bicarpellate, simple-leaved, woody, and paleotropical. Phylogenetic analysis at the family level suggests that apiaceous subfamily Hydrocotyloideae, often envisioned as an intermediate group between Apiaceae and Araliaceae, is polyphyletic, with some hydrocotyloids closely allied with Araliaceae rather than Apiaceae. With the exception of some hydrocotyloids, Apiaceae appear to be monophyletic. The relationship between Apiaceae and Araliaceae remains problematic. Although the shortest rbcL trees suggest that Apiaceae are derived from within a paraphyletic Araliaceae, this result is only weakly supported. 相似文献