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1.
Fusarium graminearum A 3/5 possesses a high affinity system (Km = 32 +/- 8 microM; mean +/- SE) for uptake of choline, which was shown to be energy-dependent and constitutive. The maximum rate of choline uptake by this system was repressed by ammonia and glucose, showing a three-fold increase in maximum activity after nitrogen (2 h) or carbon (4 h) starvation. The system was highly specific for choline with only dimethylethanolamine (Ki = 198 +/- 29 microM), betaine aldehyde (Ki = 95 +/- 14 microM) and chlorocholine (Ki = 352 +/- 40 microM) acting as competitive inhibitors. Hemicholinium-3 acted as a mixed (non-competitive) inhibitor (KIES = 1.9 +/- 0.6 microM; KIE = 3.6 +/- 1.9 microM). 相似文献
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Two morphologically distinct cell types of Coxiella burneti phase I have been separated on the basis of unique buoyant densities. When centrifuged to equilibrium in cesium chloride or density gradients of sucrose or Renografin, the cells band in two zones. Electron micrographs of ultrathin sections of the two cesium chloride-separated cell types indicate a considerable number of morphological differences. The lower-density cells are small, compact, and rodshaped and have very dense nucleoids. The cell type of highest density is larger, rounded, and more pleomorphic, and the nucleoid filaments are more dispersed. The two cell types are nearly identical in sedimentation rates, and both infect chick yolk sac cells and are lethal to chick embryos. They convert to a mixture of cell types when cultured separately. Treatment with Formalin induces all cells to band at the same position when centrifuged to equilibrium in cesium chloride. The cell type variance was found to be independent of the antigenic phase phenomenon of C. burneti. 相似文献
3.
Habitat selection by wintering male and female Snowy Owls on the Canadian prairies in relation to prey abundance and a competitor,the Great Horned Owl 下载免费PDF全文
Birds overwintering at high latitudes may find it challenging to meet their energy budgets when thermoregulatory costs are high and food availability is low. Snowy Owls (Bubo scandiacus), like most raptors, exhibit reversed sexual size dimorphism, so , if availability of high‐quality (food‐rich) habitats is limited, we predicted that larger and dominant females would use better ‐ quality habitat than males. During the winters of 2014–2015 and 2015–2016 in Saskatchewan , where many Snowy Owls overwinter annually, we measured prey (small mammal) abundance in fields with four types of cover, including cut stalks (stubble) of canola, grain and legume crops, and pasture, and related this estimate of quality to habitat selection by males and females. Small mammal abundance varied annually , but not among the three types of crop stubble. However, prey were less abundant in pastures than in the three types of crop cover in one of three years. Biweekly surveys of owls conducted during the two winters along a 60 ‐ km transect revealed weak selection for legume fields, especially by males. The home ranges of nine females with transmitters included proportionally less canola stubble than those of eight males with transmitters. Within home ranges, males avoided canola stubble and tended to use legume fields more, whereas females used all four habitat types in proportion to availability. Fewer Snowy Owls than expected were observed at locations along the transect within 800 m of Great Horned Owls (Bubo virginianus) and their associated habitats , suggesting that Snowy Owls also avoided these potential competitors on the landscape. Our results suggest that larger females outcompete smaller male Snowy Owls for home ranges in preferred habitat with less canola stubble because stubble‐free legume fields provide easier access to prey than canola fields with numerous rigid stalks. 相似文献
4.
A radioimmunoassay for the regulatory allylic steroid, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha HP)
J P Wiebe K J Barr K D Buckingham 《The Journal of steroid biochemistry and molecular biology》1991,38(4):505-512
The allylic steroid, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha HP), found in gonadal and brain tissues by radiotracer and chemical methods, had been shown to play a role in gametogenesis, gonadotropin secretion and brain excitability. Since no simple assay was available, a radioimmunoassay for 3 alpha HP was developed using [3H]3 alpha HP and an antiserum raised against 3 alpha HP-20-CMO conjugated to bovine serum albumin. The specificity of the assay for the 3 alpha allylic configuration of 3 alpha HP was confirmed by examining 32 other steroids; cross-reaction with steroids containing different configurations (including metabolites of 3 alpha HP such as progesterone) was less than 0.9%. A Scatchard plot indicated a Ka of 1.56 X 10(9) M-1. Inter- and intra-assay coefficients of variation were 13.1 and 4.5%, respectively. The sensitivity of the assay was 6 pg and the 50% intercept of the standard curve was approx. 123 pg. The measurement by RIA of 3 alpha HP from standard solutions and HPLC purified tissue extracts was confirmed qualitatively and quantitatively by GC/MS methods. The RIA method was employed to determine 3 alpha HP levels in cultured Sertoli cells and in serum of intact and ovariectomized adult rats. Although for most uses, chromatography would not be necessary, two possible methods are presented to enable the separation of 3 alpha HP from other interfering steroids prior to RIA. 相似文献
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Ann-Christin E. Brehler Wolfgang Hartmann Stefanie Wiebe Andrea Kerkhoff Christoph Schliemann Daniel Palmes Norbert Senninger Frank Lenze Hansjoerg Ullerich Wolfgang E. Berdel Torsten Kessler 《PloS one》2015,10(4)
Background
Perioperative chemotherapy increases the overall and progression-free survival of patients suffering from resectable adenocarcinomas of the lower esophagus, gastroesophageal junction and stomach (GEC). Comparing different chemotherapy regimens platin-based protocols with 5-fluorouracil (5-FU)/calcium folinate (CF) or oral fluoropyrimidines were favorable in terms of efficacy and side-effects. However, there is no consensus which regimen is the most efficacious.Methods
42 consecutive patients with resectable GEC (UICC II and III) were treated with 3 pre- and postoperative chemotherapy cycles each consisting of epirubicin, oxaliplatin and capecitabine (EOX). We analyzed the overall survival, progression-free survival and toxicity retrospectively in comparison to published data.Results
The median overall survival in our cohort was 29 months and the progression-free survival was 17 months. The most frequent grade 3 and 4 toxicities during preoperative chemotherapy were diarrhea (16.7%), leukocytopenia (9.5%) and nausea (9.5%); overall 38.1% of our patients suffered from grade 3 or 4 toxicity. Surgery was carried out in 83% of our patients, 69% of those achieved R0 resection.Conclusion
Comparing our data with the results of previously published randomized trials EOX is at least non-inferior with regard to overall survival, progression-free survival and toxicity. In conclusion, EOX is an appropriate perioperative therapy for patients with resectable GEC. 相似文献10.
Chun L. Li Matt P. Ashworth Andrzej Witkowski Przemys?aw D?bek Linda K. Medlin Wiebe H. C. F. Kooistra Shinya Sato Izabela Zg?obicka Krzysztof J. Kurzyd?owski Edward C. Theriot Jamal S. M. Sabir Mohammad A. Khiyami Mohammed H. Z. Mutwakil Meshaal J. Sabir Njud S. Alharbi Nahid H. Hajarah Song Qing Robert K. Jansen 《PloS one》2015,10(10)
Plagiogrammaceae, a poorly described family of diatoms, are common inhabitants of the shallow marine littoral zone, occurring either in the sediments or as epiphytes. Previous molecular phylogenies of the Plagiogrammaceae were inferred but included only up to six genera: Plagiogramma, Dimeregramma, Neofragilaria, Talaroneis, Psammogramma and Psammoneis. In this paper, we describe a new plagiogrammoid genus, Orizaformis, obtained from Bohai Sea (China) and present molecular phylogenies of the family based on three and four genes (nuclear-encoded large and small subunit ribosomal RNAs and chloroplast-encoded rbcL and psbC). Also included in the new phylogenies is Glyphodesmis. The phylogenies suggest that the Plagiogrammaceae is composed of two major clades: one consisting of Talaroneis, Orizaformis and Psammoneis, and the second of Glyphodesmis, Psammogramma, Neofragilaria, Dimeregramma and Plagiogramma. In addition, we describe three new species within established genera: Psammoneis obaidii, which was collected from the Red Sea, Saudi Arabia; and Neofragilaria stilus and Talaroneis biacutifrons from the Mozambique Channel, Indian Ocean, and illustrate two new combination taxa: Neofragilaria anomala and Neofragilaria lineata. Our observations suggest that the biodiversity of the family is strongly needed to be researched, and the phylogenetic analyses provide a useful framework for future studies of Plagiogrammaceae. 相似文献