Alternative sigma factors play a key role in the physiology of Bacillus anthracis by regulating the transcription of the appropriate genes required for adaptation and survival. Under specific conditions, alternative sigma factors activate transcription by binding to the promoter of the genes relevant to the condition and initiate synthesis of RNA. Here we report that the transcription of predicted sigI gene in B. anthracis, BAS3231, is induced by elevated temperatures and involved in the regulation of virulence gene expression. We show that BAS3231 is required for cell viability at elevated temperatures. We have also demonstrated that mutation in the BAS3231 gene results in a decrease in virulence gene expression. Our study provides new insight into the role of alternative sigma factors in B. anthracis.

This thesis presents an overview of the simulation, design, and measurement of state-of-the-art Silicon-Germanium Heterojunction Bipolar Transistor (SiGe HBT) variable gain amplifier (VGA). The VGA design trade-off space is presented and methods for achieving an optimized design are discussed. We demonstrate in this thesis that SiGe HBT VGA has the capability to meet the demanding needs for the next generation wireless systems.

RNA polymerase (RNAP) is a key enzyme in regulation of bacterial gene expression. RNAP is multi-subunit enzyme and its σ subunits (factors) are used for DNA recognition. Regulation of RNAP complexed with the major σ factor has been thoroughly studied; in contrast, mechanisms of regulation of RNAP containing alternative σ factors are much less understood. This thesis is focused mainly on the model organism Bacillus subtilis and its alternative σ factors σF , σG , σI a σK . We studied the ability of RNAP in complex with these factors to recognize promoter sequences, to initiate transcription in dependence on the concentration of the initiating nucleoside triphosphate (iNTP), and to interact with selected proteins. For σF , a promoter regulated by the concentration of iNTP was discovered; for σI , to the contrary, this mechanism was not observed. In the case of σG -dependent transcription we were not able to examine regulation by the concentration of iNTP. Nevertheless, stimulation of σG -dependent transcription by a protein called YlyA, previously described in the literature, was confirmed. This stimulation was newly identified also for σF -dependent transcription. Further, we examined possible functional interaction between HelD and σK , but this link was not confirmed. Finally, this thesis...

The problem with which this study is concerned is to determine if the System of Interactive Guidance and Information (SIGI), which is a computer-based career guidance system that is employed with non-handicapped individuals, can be adapted to serve the needs of physically handicapped individuals. One hundred forty eight career and guidance professionals responded to a survey instrument, which was designed by the investigator, indicating their perceptions of the limiting effects of twelve specified handicapping conditions on the SIGI-programmed occupations. These respondents also listed their specific occupations, average time spent in career counseling with each handicapped individual, resources used in career counseling, incidence of use of SIGI, and opinions of needed changes to SIGI to make it a viable instrument in counseling the handicapped.