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The restriction deficient mutant 8195 of Acholeplasma laidlawii strain JA1 was transformed by the promiscuous streptococcal plasmid vector pNZ18 at a frequency of 4 x 10(-4)/cfu. The plasmid was maintained without structural rearrangements but was lost in the absence of a selection pressure, i.e. kanamycin or neomycin. Transformed primary colonies were easily recognized due to a different colony morphology. Replica filter plating, previously not obtained with mycoplasmas, was achieved using pNZ18 as a marker by incubating the replica filters with the cell side down on the new agar plates. These findings should greatly facilitate the genetic and functional analysis of A. laidlawii. 相似文献
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K. -M. Exo F. Bairlein S. Klaus E. Bezzel W. Epple und B. Nicolai 《Journal of Ornithology》1999,140(3):367-376
Ohne Zusammenfassung 相似文献
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Identification of an Obese Eating Style in 4‐year‐old Children Born at High and Low Risk for Obesity
Robert I. Berkowitz Renee' H. Moore Myles S. Faith Virginia A. Stallings Tanja V.E. Kral Albert J. Stunkard 《Obesity (Silver Spring, Md.)》2010,18(3):505-512
This study tested whether children's eating behavior and parental feeding prompts during a laboratory test meal differ among children born at high risk (HR) or low risk (LR) for obesity and are associated with excess child weight gain. At 4 years of age, 32 HR children (mean maternal prepregnancy BMI = 30.4 kg/m2) and 29 LR children (maternal BMI = 19.6 kg/m2) consumed a test meal in which their eating behavior was assessed, including rate of caloric consumption, mouthfuls/min, and requests for food. Parental prompts for the child to eat also were measured at year 4, and child body composition was measured at ages 4 and 6 years. T‐tests, and logistic and multiple regression analyses tested study aims. Results indicated that HR and LR children did not differ in eating rate or parental feeding prompts. Greater maternal BMI, child mouthfuls of food/min, and total caloric intake/min during the test meal predicted an increased risk of being overweight or obese at age 6, whereas greater active mealtime was associated with a reduced risk of being overweight or obese. Regression analyses indicated that only mouthfuls of food/min predicted changes in BMI from 4 to 6 years, and mouthfuls of food/min and gender predicted 2‐year changes in sum of skinfolds and total body fat. Thus, a rapid eating style, characterized by increased mouthfuls of food/min, may be a behavioral marker for the development of childhood obesity. 相似文献
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Igor A. Mikhailopulo Nicolai E. Poopeiko Grigorii G. Sivets Natalia B. Khripach 《Nucleosides, nucleotides & nucleic acids》2013,32(3-5):383-384
Abstract Oxidation of 1a with DMSO-acetic or trifluoroacetic anhydride led to the formation of a mixture of epimeric gem-diols 2 and 3 in the ratios of ?3:1 and ?7:1, respectively. Reduction of this mixture with NaBH4 followed by benzoylation and chromatography afforded 4a and 5a. 相似文献
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Dmitri Shcherbakov Rashid Akbergenov Tanja Matt Peter Sander Dan I. Andersson Erik C. Böttger 《Molecular microbiology》2010,77(4):830-840
Drug resistance in Mycobacterium tuberculosis is a global problem, with major consequences for treatment and public health systems. As the emergence and spread of drug‐resistant tuberculosis epidemics is largely influenced by the impact of the resistance mechanism on bacterial fitness, we wished to investigate whether compensatory evolution occurs in drug‐resistant clinical isolates of M. tuberculosis. By combining information from molecular epidemiology studies of drug‐resistant clinical M. tuberculosis isolates with genetic reconstructions and measurements of aminoglycoside susceptibility and fitness in Mycobacterium smegmatis, we have reconstructed a plausible pathway for how aminoglycoside resistance develops in clinical isolates of M. tuberculosis. Thus, we show by reconstruction experiments that base changes in the highly conserved A‐site of 16S rRNA that: (i) cause aminoglycoside resistance, (ii) confer a high fitness cost and (iii) destabilize a stem‐loop structure, are associated with a particular compensatory point mutation that restores rRNA secondary structure and bacterial fitness, while maintaining to a large extent the drug‐resistant phenotype. The same types of resistance and associated mutations can be found in M. tuberculosis in clinical isolates, suggesting that compensatory evolution contributes to the spread of drug‐resistant tuberculosis disease. 相似文献
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E. Bezzel J. Nicolai R. Prinzinger H. Utschick und S. Schuster 《Journal of Ornithology》1979,120(1):106-115
Ohne Zusammenfassung 相似文献