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991.
Disha-Gajanan Hiregange Andre Rivalta Tanaya Bose Elinor Breiner-Goldstein Sarit Samiya Giuseppe Cimicata Liudmila Kulakova Ella Zimmerman Anat Bashan Osnat Herzberg Ada Yonath 《Nucleic acids research》2022,50(3):1770
Giardiasis is a disease caused by the protist Giardia lamblia. As no human vaccines have been approved so far against it, and resistance to current drugs is spreading, new strategies for combating giardiasis need to be developed. The G. lamblia ribosome may provide a promising therapeutic target due to its distinct sequence differences from ribosomes of most eukaryotes and prokaryotes. Here, we report the cryo-electron microscopy structure of the G. lamblia (WB strain) ribosome determined at 2.75 Å resolution. The ribosomal RNA is the shortest known among eukaryotes, and lacks nearly all the eukaryote-specific ribosomal RNA expansion segments. In contrast, the ribosomal proteins are typically eukaryotic with some species-specific insertions/extensions. Most typical inter-subunit bridges are maintained except for one missing contact site. Unique structural features are located mainly at the ribosome’s periphery. These may be exploited as target sites for the design of new compounds that inhibit selectively the parasite’s ribosomal activity. 相似文献
992.
Barbara Ambrožič Turk Harry J. Swartz Richard H. Zimmerman 《Plant Cell, Tissue and Organ Culture》1994,38(1):11-17
Regeneration of adventitious shoots from leaves of several in vitro-cultured Rubus genotypes was affected by media components and incubation conditions. Leaves cultured at 20°C with a photosynthetic photon flux (PPF) of 40 mol m-2 s-1 had a higher regeneration frequency and more shoots per regenerating leaf than ones cultured at 25°C with a PPF of either 40 or 80 mol m-2 s-1. Thidiazuron (TDZ) was significantly more effective than benzyladenine. Medium containing 1 M TDZ had the highest percentage regeneration for leaves of Autumn Bliss, Canby, Summit and Sentry red raspberries, whereas leaves of MD-ETCE-1 blackberry hybrid responded more to 10 M TDZ. Higher regeneration frequencies were obtained with 0.5 M indolebutyric acid (IBA) than with 1 M, but no significant difference was observed between 0.5 M and no IBA in other experiments. More shoots per regenerating leaf formed on Murashige and Skoog (MS) and N6 media, than on half-strength MS, Anderson, or Woody Plant media for all genotypes tested. The youngest two expanding leaves near the shoot apex were the most regenerative and yielded the highest number of shoots per regenerating leaf.Abbreviations AND
Anderson (1980)
- BA
benzyladenine
- IBA
indolebutyric acid
- MS
Murashige & Skoog (1962)
- N6
Chu et al. (1975)
- NAA
naphthaleneacetic acid
- PPF
photosynthetic photon flux
- TDZ
thidiazuron (N-phenyl-N'-1, 2, 3-thiadiazol-5-ylurea)
- WPM
Woody Plant Medium [Lloyd & McCown (1980)] 相似文献
993.
994.
Asynchronous fluctuation of soil microbial biomass and plant litterfall in a tropical wet forest 总被引:4,自引:0,他引:4
Carbon availability often controls soil microbial growth and there is evidence that at regional scales soil microbial biomass is positively correlated with aboveground forest litter input. We examined the influence of plant litterfall on annual variation of soil microbial biomass in control and litter-excluded plots in a tropical wet forest of Puerto Rico. We also measured soil moisture, soil temperature, and plant litterfall in these treatment plots. Aboveground plant litter input had no effect on soil microbial biomass or on its pattern of fluctuation. Monthly changes in soil microbial biomass were not synchronized with aboveground litter inputs, but rather preceeded litterfall by one month. Soil microbial biomass did not correlate with soil temperature, moisture, or rainfall. Our results suggest that changes in soil microbial biomass are not directly regulated by soil temperature, moisture, or aboveground litter input at local scales within a tropical wet forest, and there were asynchronous fluctuation between soil microbial biomass and plant litterfall. Potential mechanisms for this asynchronous fluctuation include soil microbial biomass regulation by competition for soil nutrients between microorganisms and plants, and regulation by below-ground carbon inputs associated with the annual solar and drying-rewetting cycles in tropical wet forests. 相似文献
995.
Forrest H. Nielsen Terrence R. Shuler Thomas J. Zimmerman Michael E. Collings Eric O. Uthus 《Biological trace element research》1979,1(4):325-335
The interaction between nickel and iron was confirmed in rat metabolism. In a fully-crossed, two-way, three by four, factorially
designed experiment, female weanling rats were fed a basal diet supplemented with iron at 0, 25, 50, and 100 μg/g and with
nickel at 0, 5, and 50 μg/g. The basal diet contained about 10 ng of nickel and 2.3 μg of iron/g. After nine weeks, dietary
iron affected growth, hematocrit, hemoglobin, plasma cholesterol, and in liver affected total lipids, phospholipids, and the
contents of copper, iron, manganese, and zinc. By manipulating the iron content of the diet, effects of dietary nickel were
shown in rats that were not from dams fed a nickel-deprived diet. Nickel affected growth, hematocrit, hemoglobin, plasma alkaline
phosphatase activity, plasma total lipids, and in liver affected total lipids, and the contents of copper, manganese, and
nickel. The interaction between nickel and iron affected hematocrit, hemoglobin, plasma alkaline phosphatase activity, and
plasma phospholipids, and in liver affected size, content of copper, and perhaps of manganese and nickel. In severely iron-deficient
rats, the high level of dietary nickel partially alleviated the drastic depression of hematocrit and hemoglobin, and the elevation
of copper in liver. Simultaneously, high dietary nickel did not increase the iron level in liver and was detrimental to growth
and appearance of severely iron-deficient rats. In nickel-deprived rats fed the borderline iron-deficient diet (25 μg/g) hematocrit
and hemoglobin also were depressed. However, 5 μg Ni/g of diet were just as effective as 50 μg Ni/g of diet in preventing
those signs of nickel deprivation. The findings in the present study suggested that nickel and iron interact with each other
at more than one locus. 相似文献
996.
997.
Morbidity and mortality in infant mountain gorillas (Gorilla beringei beringei): A 46‐year retrospective review 下载免费PDF全文
998.
Earl G. Zimmerman Ronald L. Merritt Michael C. Wooten 《Biochemical Systematics and Ecology》1980,8(4):447-453
Genetic variation at 17 enzymic and other protein loci was examined for natural populations of stoneroller minnows, Campostoma oligolepis and C. anomalum. Species differences in levels of heterozygosity, standardized variance of gene frequencies and interpopulation heterogeneity appear to be a function of degree of demic isolation, rate of migration and potential for stochastic processes to structure genomes. 相似文献
999.
The effects of a diet rich in fish oil on human neutrophils: identification of leukotriene B5 as a metabolite 总被引:3,自引:0,他引:3
Diets that are enriched with fish oil have been shown to alter arachidonic acid metabolism via the cyclooxygenase pathway. Recently it has been shown that one of the major component fatty acids of fish oil, eicosapentaenoate (EPA), is a substrate for the leukotriene B (LTB) pathway when added exogenously to human neutrophils in vitro. We fed a diet that contained 8-10gm/day of EPA to four human subjects for three weeks and compared the arachidonate metabolism of their neutrophils to the same functions while the subjects were on their usual diet. The fish oil-supplementation increased neutrophil EPA content from undetectable levels to 7.4 +/- 2.4% (p less than 0.01, expressed as % of total fatty acid), and decreased arachidonate from 15.4 +/- 2.3% to 12.8 +/- 2.3% (p less than 0.05). Leukotriene B5 was identified as a metabolite during the fish oil-diet by its chromatographic profile and mass spectrum. During the experimental diet LTB4, decreased from 160 +/- 37 ng/10(7) neutrophils to 120 +/- 12 (p less than 0.05), and LTB5 increased from 0 to 39 +/- 9 ng/10(7) neutrophils (p less than 0.005). The diet had no effect on neutrophil aggregation or adherence to nylon fibers. 相似文献