The mechanism for the electrooxidation of procarbazine pharmaceutical preparation in alkaline media and its mathematical description

The mechanism for the electrooxidation of procarbazine in alkaline media has been proposed. The process is realized completely on the electrode surface and is adsorption-controlled. The oscillatory behavior in this case is more probable, than for neutral media and may be caused by influences of electrochemical oxidation and salt dissolution from the electrode surface

Математическое описание «политиофенового парадокса» для потенциостатической электрополимеризации электрохимически модифицированных тиофенов

The phenomenon of "polythiophene paradox" for insoluble polythiophenes based on electrochemically modified monomers has been described theoretically. The corresponding mathematical model was examined using linear theory of stability and bifurcation analysis. Stability conditions of steady state, monotonic and oscillatory instabilities have also been obtained.Явление «политиофенового парадокса» для нерастворимых политиофенов на основе электрохимически модифицированных мономеров было описано теоретически. Соответствующая математическая модель была рассмотрена с помощью линейной теории устойчивости и бифуркационного анализа. Условия устойчивости стационарного состояния, монотонной и автоколебательной неустойчивостей также были получены

Two subfamilies of murine retrotransposon ETn sequences

Early transposon (ETn) elements are 5.7-kb retrotransposons found in the murine genome. We have sequenced large portions of two ETn elements that have apparently transposed within the DNA of a murine myeloma cell line, P3.26Bu4. One of the transposed ETn elements has 5' and 3' long terminal repeats (LTRs) that are exact duplicates of each other and has a 6-bp target site duplication. These results suggest that this element, which inserted into an immunoglobulin [gamma]1 switch region, moved by a retrotransposition process. Our nucleotide sequences confirm that individual ETn elements are very similar to one another and lack open reading frames. However, the ETn sequences reported here and those previously described differ significantly near their 5' LTRs, including 200 bp of weak similarity and 240 bp of complete disparity. Southern hybridization analysis suggests that both subfamilies of ETn sequences are represented many times in the mouse genome. The possibility that the disparate sequences have a role in transposition by ETn elements is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28722/1/0000543.pd

Germline transcription of the murine immunoglobulin gamma-1 locus: Characterization of the promoter elements in transgenic mice.

During the murine immune response, mice can produce eight classes of antibody molecules. These classes are defined by the heavy chain constant regions which are encoded by genes found on chromosome 12. Naive B cells express antibodies of the IgM and IgD classes on their surfaces, but upon antigenic stimulation, the cells can change the class of antibody produced to one of the other six classes. This class switching is effected by a DNA recombination event between specialized DNA sequences (switch regions) found upstream of each of the constant region genes. After the recombination event, the gene encoding the antigen binding domain of the antibody is juxtaposed to the gene for a downstream heavy chain constant region. In part of this work, the insertion of an E.Tn element into the $\gamma$2a switch region of plasmacytoma P3.26Bu4 was characterized. The analysis suggested the involvement of switch recombination enzymes in this insertion of the retrotransposon. Prior to the recombination event, the constant region genes are transcribed in their germline configuration. This transcription initiates in a region upstream of the switch region and is induced by cytokines. The main part of this thesis investigated the cis-acting elements that regulate the germline transcription of the IgGl gene in a transgenic mouse system. We generated transgenic mice with promoter region fragments directing the transcription of reporter genes, and characterized their expression patterns. The promoter fragments included 3500, 2300, 1700, or 335 basepairs of sequences near the transcription start sites. Another construct contained 17 kilobases, beginning 2100 basepairs upstream of the start sites and extending downstream through the entire switch and constant regions. Our results indicated that the 17 kilobase construct contained all of the elements required for regulated transcription of the locus. All of the smaller constructs, including the 335 basepair promoter region construct, are transcribed almost exclusively in lymphoid cells; but they lack a negative element found in the 17 kilobase construct that prevents inappropriate expression.Ph.D.Microbiology and ImmunologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/103932/1/9423179.pdfDescription of 9423179.pdf : Restricted to UM users only

A hallmark of active class switch recombination: Transcripts directed by I promoters on looped-out circular DNAs

To specify when and where Ig class switch recombination (CSR) takes place, a good molecular marker closely associated with active CSR is required. CSR is accompanied by deletion of circular DNA from the Ig heavy chain locus. The circular DNA contains a DNA segment between Sμ and a target S region including its I promoter, which is driven by specific cytokine stimulation before CSR. We found that the specific I promoter is still active in looped-out circular DNA and directs production of I-Cμ transcripts termed “circle transcripts.” Reverse transcription–PCR demonstrated transient induction of specific circle transcripts upon CSR in a murine lymphoma cell line, CH12F3-2A, as well as spleen B cells. Production of the circle transcripts appeared to depend on expression of activation-induced cytidine deaminase (AID), an essential factor for CSR. A comparison of kinetics between circle transcripts and circular DNA showed more rapid disappearance of circle transcripts. Thus, circle transcripts may serve as a hallmark for active CSR in vitro and in vivo