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Full-Text Articles in Life Sciences
Properties Of The Merozygotes Associated With A Sulfonamide-Resistant Mutation In Pneumococcus, Mary Lee Stewart Ledbetter
Properties Of The Merozygotes Associated With A Sulfonamide-Resistant Mutation In Pneumococcus, Mary Lee Stewart Ledbetter
Student Theses and Dissertations
Unstable prokaryotic strains arise occasionally under a variety of circumstances and with a variety of properties which make them amenable to genetic and physiological analysis at different levels of precision. A review of a number of such unstable systems, initially identified on the basis of a regular segregation to phenotypically non-parental types, has led to the recognition of a series of criteria for the systematic analysis of such strains. These criteria are applied to a sulfanilamideresistant mutant of pneumococcus which regularly segregates to strains sensitive to sulfanilamide and resistant to p-nitrobenzoic acid, another analogue of paraminobenzoic acid.
The Biogenesis Of Peroxisomal Catalase In Rat Liver, Paul Bernard Lazarow
The Biogenesis Of Peroxisomal Catalase In Rat Liver, Paul Bernard Lazarow
Student Theses and Dissertations
Rat liver peroxisomal catalase was purified to homogeneity. The starting material was purified peroxisomes, The purity of the final preparation was judged by Sephadex G-200 chromatography, SDS gel electrophoresis, spectral analysis, and immunochemical means. Two sera containing anticatalase antibodies were prepared. The first, a rabbit serum, contained a minor impurity. The anticatalase was purified forty times by affinity chromatography and the contaminating antibodies were thereby removed. The second serum, prepared in a goat, was proved to be monospecific by immunodiffusion and immunoelectrophoresis.
A Mineralocorticoid-Dependent Effect Of Prestress On Avoidance Responding In Rats, Peter Gray
A Mineralocorticoid-Dependent Effect Of Prestress On Avoidance Responding In Rats, Peter Gray
Student Theses and Dissertations
Rats made more free-operant avoidance responses if they were given a brief prestress 30 min before the test than if they were undisturbed before the test. This effect of prestress occurred in normal rats whether foot shock, air blast, or simple handling served as the prestress. The effect did not, however, occur in adrenalectomized rats. The effect also did not occur in intact rats who were maintained on 1.5% NaCl drinking fluid, a procedure which is known to inhibit mineralocorticoid secretion. Injection of mineralocorticoid, in either adrenalectomized rats or intact NaCl-maintained rats, renewed the effect of prestress and had no …
An Analysis Of Spatial Summation In The Receptive Fields Of Goldfish Retinal Ganglion Cells, Michael William Levine
An Analysis Of Spatial Summation In The Receptive Fields Of Goldfish Retinal Ganglion Cells, Michael William Levine
Student Theses and Dissertations
The axons of retinal ganglion cells convey the signals from which the brain constructs its visual percept of the world. The considerable processing done in the retina is implicit in these signals; it is therefore desirable to understand this processing in some detail. Only one aspect of retinal processing is considered--the spatial interactions within either the center or the surround of the receptive field of the ganglion cell. A generalized model for this restricted processing is proposed: the independent signals in each of two separately stimulated areas may undergo non-linear transformation; the two areas may interact at one or several …
Purification And Properties Of Bacteriophage F2 Replicase, Nina V. Fedoroff
Purification And Properties Of Bacteriophage F2 Replicase, Nina V. Fedoroff
Student Theses and Dissertations
The present dissertation concerns the purification and properties of an RNA-dependent ribonucleotide-polymerizing enzyme (RNA replicase) produced during infection of E. coli with the RNA bacteriophage f2. Studies on the RNA replicase of the distantly-related bacteriophage Q3 have established the feasibility of using a simplified assay for replicase activity based on the ability of the enzyme to polymerize GTP in the presence of polycytidylic acid template. A similar poly Cdependent poly G polymerase activity is detectable in E. coli infected with bacteriophage f2. The f2 poly G polymerase has been purified by ion exchange chromatography on DEAE cellulose, affinity chromatography on …
Patterns Of Electrical Communication Among Gymnotoid Fish, Carl Douglas Hopkins
Patterns Of Electrical Communication Among Gymnotoid Fish, Carl Douglas Hopkins
Student Theses and Dissertations
This paper presents the results of a twelve-month field study of the behavior and ecology of gymnotid fish from the Rupununi District of Guyana, South America, and from Trinidad, W.I. There are 13 species of gymnotids in the Rupununi District, of which six to eight species occur frequently in the main study area in Moco-moco Creek. All species produce electrical discharges which are presumably used for object location and for electrical communication. Gymnotids are active at night and inactive during the day. Some species tend to specialize on the types of daytime hiding places selected, while others generalize. Eigenmannia virescens …