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31.
All monodeoxygenated galactoses were treated with galactokinase, and for the 2-, 3-, and 4-deoxy compounds, transformation into the corresponding galactopyranosyl phosphates could be observed. In case of the 2-deoxy derivative, further reaction via UDP-2-deoxy-d-lyxo-hexose (UDP-2-deoxygalactose), which was also obtained chemically, the multiple enzymatic system could be employed to prepare 2′-deoxy-N-acetyllactosamine. 相似文献
32.
EM Tazi I Lalya MF Tazi Y Ahellal H M'rabti H Errihani 《World journal of surgical oncology》2010,8(1):1-3
Goblet cell carcinoid of the large intestine is a rare neoplasm, usually located in ascending colon and rectum. A 60-year-old male patient underwent surgery after the diagnosis of acute abdomen. Exploratory laparotomy revealed perforation with a diameter of 1 cm at the site of the previously performed gastroenterostomy and dilatation of the right colic flexure, secondary to a solid obstructive mass located in the mid-portion of transverse colon. Histopathological investigation of the biopsies, taken from the gastroenterostomy site and the tumor, revealed mixed carcinoid-adenocarcinoma with carcinoid component, predominantly composed of goblet cells. Three cycles of FOLFOX-4 protocol was administered. Following respiratory distress secondary to pulmonary metastasis, the patient's condition deteriorated and subsequently died in the fourth postoperative month. Our aim with this paper is to point out that more cases should be reported for more effective diagnosis, histopathological study, clinical investigation, treatment and prognosis of this specific neoplasm. 相似文献
33.
Glutamine synthetase of Klebsiella aerogenes: properties of glnD mutants lacking uridylyltransferase. 总被引:2,自引:12,他引:2 下载免费PDF全文
F Foor R J Cedergren S L Streicher S G Rhee B Magasanik 《Journal of bacteriology》1978,134(2):562-568
The glnD mutation of Klebsiella aerogenes is cotransducible by phage P1 with pan (requirement for pantothenate) and leads to a loss of uridylytransferase and uridylyl-removing enzyme, components of the glutamine synthetase adenylylation system. This defect results in an inability to deadenylylate glutamine synthetase rapidly and in a requirement for glutamine for normal growth. Suppression of the glnD mutation are located at the glutamine synthetase structural gene glnA. 相似文献
34.
Jason J. Luke Pierre L. Triozzi Kyle C. McKenna Erwin G. Van Meir Jeffrey E. Gershenwald Boris C. Bastian J. Silvio Gutkind Anne M. Bowcock Howard Z. Streicher Poulam M. Patel Takami Sato Jeffery A. Sossman Mario Sznol Jack Welch Magdalena Thurin Sara Selig Keith T. Flaherty Richard D. Carvajal 《Pigment cell & melanoma research》2015,28(2):135-147
Uveal melanoma is the most common intraocular malignancy although it is a rare subset of all melanomas. Uveal melanoma has distinct biology relative to cutaneous melanoma, with widely divergent patient outcomes. Patients diagnosed with a primary uveal melanoma can be stratified for risk of metastasis by cytogenetics or gene expression profiling, with approximately half of patients developing metastatic disease, predominately hepatic in location, over a 15‐yr period. Historically, no systemic therapy has been associated with a clear clinical benefit for patients with advanced disease, and median survival remains poor. Here, as a joint effort between the Melanoma Research Foundation's ocular melanoma initiative, CURE OM and the National Cancer Institute, the current understanding of the molecular and immunobiology of uveal melanoma is reviewed, and on‐going laboratory research into the disease is highlighted. Finally, recent investigations relevant to clinical management via targeted and immunotherpies are reviewed, and next steps in the development of clinical therapeutics are discussed. 相似文献
35.
36.
Regulation of Nitrogen Fixation in Klebsiella pneumoniae: Evidence for a Role of Glutamine Synthetase as a Regulator of Nitrogenase Synthesis 总被引:19,自引:34,他引:19 下载免费PDF全文
Stanley L. Streicher K. T. Shanmugam Frederick Ausubel Carlo Morandi Richard B. Goldberg 《Journal of bacteriology》1974,120(2):815-821
Mutations causing constitutive synthesis of glutamine synthetase (GlnC(-) phenotype) were transferred from Klebsiella aerogenes into Klebsiella pneumoniae by P1-mediated transduction. Such GlnC(-) strains of K. pneumoniae have constitutive levels of glutamine synthetase. Two of three GlnC(-) strains of K. pneumoniae studied, each containing independently isolated mutations that confer the GlnC(-) phenotype, continue to synthesize nitrogenase in the presence of NH(4) (+). One strain, KP5069, produces 30% as much nitrogenase when grown in the presence of 15 mM NH(4) (+) as in its absence. The GlnC(-) phenotype allows the synthesis of nitrogenase to continue under conditions that completely repress nitrogenase synthesis in the wild-type strain. Glutamine auxotrophs of K. pneumoniae, that do not produce catalytically active glutamine synthetase, are unable to synthesize nitrogenase during nitrogen limited growth. Complementation of K. pneumoniae Gln(-) strains by an Escherichia coli episome (F'133) simultaneously restores glutamine synthetase activity and the ability to synthesize nitrogenase. These results indicate a role for glutamine synthetase as a positive control element for nitrogen fixation in K. pneumoniae. 相似文献
37.
Polygalacturonase inhibiting protein (PGIP) is localized in plant cell walls and plays an important role both in pectic substance metabolism and in prevention of the penetration of phytopathogenic microorganisms. Apparently, PGIP is responsible for the specificity of cell--cell interactions during pollination or inoculation by fungi nonpathogenic for the particular plant. PGIPs from different plants share a basic common structure. They are rather thermostable glycoproteins enriched with leucine and contain about 20% carbohydrates; the molecular weight varies between 37-54 kD. The synthesis of PGIP is encoded by one gene, and its expression is stimulated by injury and fungal infection. The resistance of plant tissues to infection frequently correlates with PGIP expression and with inhibiting action on fungal PG. Thus, PGIP is believed to be useful for gene engineering to obtain transgenic plants resistant to fungal infection or retaining commercial value during storage. 相似文献
38.
First-egg date fluctuations for the Pied Flycatcher Ficedula hypoleuca in the woodlands of mid-Wales in the twentieth century 总被引:1,自引:1,他引:0
EM. SLATER 《Ibis》1999,141(3):497-499
39.
Liyan Jiang Jiaqi Huang Brandon W. Higgs Zhibin Hu Zhan Xiao Xin Yao Sarah Conley Haihong Zhong Zheng Liu Philip Brohawn Dong Shen Song Wu Xiaoxiao Ge Yue Jiang Yizhuo Zhao Yuqing Lou Chris Morehouse Wei Zhu Yinong Sebastian Meggan Czapiga Vaheh Oganesyan Haihua Fu Yanjie Niu Wei Zhang Katie Streicher David Tice Heng Zhao Meng Zhu Lin Xu Ronald Herbst Xinying Su Yi Gu Shyoung Li Lihua Huang Jianren Gu Baohui Han Bahija Jallal Hongbing Shen Yihong Yao 《PLoS genetics》2016,12(4)
40.
Glutamine synthetase of Streptomyces cattleya: purification and regulation of synthesis 总被引:3,自引:0,他引:3
Glutamine synthetase (GS; EC 6.3.1.2) from Streptomyces cattleya was purified using a single affinity-gel chromatography step, and some of its properties were determined. Levels of GS in S. cattleya cells varied by a factor of 8 depending upon the source of nitrogen in the growth medium. Of 24 nitrogen sources examined only glutamine or NH4Cl utilization resulted in very low GS activity. Addition of NH4Cl to a culture with high GS levels appeared to stop further synthesis and resulted in a progressive decrease in the specific activity of the enzyme. The GS inhibitor methionine sulphoximine (MSX) inhibited GS activity but had no effect on exponentially growing cells. The presence of MSX either lengthened or shortened the period between spore inoculation and initiation of exponential growth, depending on the source of nitrogen. In glutamine minimal medium MSX produced earlier and more efficient spore germination while in glutamate or nitrate minimal medium germination was delayed by its presence. 相似文献