Cartographic research in EREP program for small scale mapping

The author has identified the following significant results. Skylab photography is suitable for producing planimetric maps with graphical representation of landform at scales up to 1:100,000. It cannot supply all the detail necessary for maps at this scale, but it may be used to produce a sound framework which can be completed by detail from other sources. Its principal cartographic use is for original mapping of undeveloped areas of the world, but it would also be useful for the revision of existing maps and for monitoring extensive urban changes

Architecture of Escherichia coli promoters that respond to reactive nitrogen species

This study examined the regulation of two genes, hcp and ogt, that are reported to be involved in protection from the mutagenic effects of reactive nitrogen species in Escherichia coli. Biochemical techniques were used to investigate promoter activity and the effects of the transcription factors that are reported to regulate expression of the hcp and ogt genes, namely NarL / NarP, FNR and NsrR. Transcription activation by NarL was then studied using semi-synthetic promoters. The hcp gene was found to be positively regulated by FNR and negatively regulated by NsrR. Contrary to previous reports, NarL and NarP were found to have little direct effect on expression of hcp, however, an indirect effect of NarL was detected. This study demonstrates that the indirect effect on hcp regulation of NarL is related to repression by NsrR and suggests that NarL is involved in the generation of reactive nitrogen species. The ogt gene was confirmed to be activated by NarL independently of FNR. Studies focused on characterising the different classes by which NarL / NarP can activate promoter activity independently of FNR. NarL was found to activate by class I, II and III mechanisms, whilst NarP was capable of class II activation only. Activation by NarL was studied and a library of alanine substitutions in the carboxyl terminal domain (CTD) of the α subunit of RNA polymerase was used to demonstrate direct interaction between NarL and RNA polymerase. NarL, the CTD of NarL, NarXL, NarP and the CTD of NarP were expressed from plasmids and transcription activation studied in cells lacking chromosomal narL and narP. Full-length NarL activated by Class I, II and III mechanisms, whilst the CTD of NarL only activated by class II mechanisms. Both the full-length NarP and the CTD of NarP only activated by class II mechanisms

Cyber threat intelligence sharing: Survey and research directions

Cyber Threat Intelligence (CTI) sharing has become a novel weapon in the arsenal of cyber defenders to proactively mitigate increasing cyber attacks. Automating the process of CTI sharing, and even the basic consumption, has raised new challenges for researchers and practitioners. This extensive literature survey explores the current state-of-the-art and approaches different problem areas of interest pertaining to the larger field of sharing cyber threat intelligence. The motivation for this research stems from the recent emergence of sharing cyber threat intelligence and the involved challenges of automating its processes. This work comprises a considerable amount of articles from academic and gray literature, and focuses on technical and non-technical challenges. Moreover, the findings reveal which topics were widely discussed, and hence considered relevant by the authors and cyber threat intelligence sharing communities

Unusual organization, complexity and redundancy at the Escherichia coil hcp-hcr operon promoter

International audienceExpression from the Escherichia coli hcp-hcr operon promoter is optimally induced during anaerobic conditions in the presence of nitrite. This expression depends on transcription activation by FNR, which binds to a target centred at position ‑72.5 upstream of the transcript start site. Mutational analysis was exploited to identify the corresponding -10 and -35 hexamer elements. A DNA site for NarL and NarP, located at position ‑104.5, plays only a minor role, whilst NsrR binding to a DNA target centred at position +6 plays a major role in induction of the hcp‑hcr operon promoter. Electromobility shift assays show that NsrR binds to this target. The consequences of this for the kinetics of induction of the hcp‑hcr operon are discussed

Activation by NarL at the <i>Escherichia coli ogt</i> promoter

The Escherichia coli NarX/NarL two-component response-regulator system regulates gene expression in response to nitrate ions and the NarL protein is a global transcription factor, which activates transcript initiation at many target promoters. One such target, the E. coli ogt promoter, which controls the expression of an O6-alkylguanine-DNA-alkyltransferase, is dependent on NarL binding to two DNA targets centred at positions −44.5 and −77.5 upstream from the transcript start. Here, we describe ogt promoter derivatives that can be activated solely by NarL binding either at position −44.5 or position −77.5. We show that NarL can also activate the ogt promoter when located at position −67.5. We present data to argue that NarL-dependent activation of transcript initiation at the ogt promoter results from a direct interaction between NarL and a determinant in the C-terminal domain of the RNA polymerase α subunit. Footprinting experiments show that, at the −44.5 promoter, NarL and the C-terminal domain of the RNA polymerase α subunit bind to opposite faces of promoter DNA, suggesting an unusual mechanism of transcription activation. Our work suggests new organisations for activator-dependent transcription at promoters and future applications for biotechnology.</jats:p

Cyber threat information sharing: Perceived benefits and barriers

The literature on cyber security information sharing enumerates an extensive list of potential benefits for organisations in both the public and private sectors. However, despite the potential benefits, successful cyber security information sharing has been difficult to achieve. We report upon a study that sought to measure the extent to which the benefits and barriers suggested by the cyber security information sharing literature are reflected in the attitudes of practising security managers and analysts. A self-administered online survey was used. The survey consisted of: several questions about the participants’ experience with cyber security information sharing; and two sets of Likert-type scale items to measure the respondents’ attitudes regarding the benefits and barriers identified in the literature. Our findings aim to highlight the gap between the theory and practice of information sharing and provide input for future research into design principles for information sharing systems and ways to mitigate threat information sharing challenges

Activation by NarL at the Escherichia coli ogt promoter

The Escherichia coli NarX/NarL two-component response-regulator system regulates gene expression in response to nitrate ions and the NarL protein is a global transcription factor, which activates transcript initiation at many target promoters. One such target, the E. coli ogt promoter, which controls the expression of an O6-alkylguanine-DNA-alkyltransferase, is dependent on NarL binding to two DNA targets centred at positions -44.5 and -77.5 upstream from the transcript start. Here, we describe ogt promoter derivatives that can be activated solely by NarL binding either at position -44.5 or position -77.5. We show that NarL can also activate the ogt promoter when located at position -67.5. We present data to argue that NarL-dependent activation of transcript initiation at the ogt promoter results from a direct interaction between NarL and a determinant in the C-terminal domain of the RNA polymerase α subunit. Footprinting experiments show that, at the -44.5 promoter, NarL and the C-terminal domain of the RNA polymerase α subunit bind to opposite faces of promoter DNA, suggesting an unusual mechanism of transcription activation. Our work suggests new organisations for activator-dependent transcription at promoters and future applications for biotechnology

A cryptic promoter in theLEE1regulatory region of enterohaemorrhagicEscherichia coli: promoter specificity in AT-rich gene regulatory regions

Transcription of the LEE1 operon in the locus of enterocyte effacement of enterohaemorrhagic Escherichia coli is due to the P1 promoter. Mutational and biochemical analyses reveal the existence of an overlapping promoter, designated P1A, which can drive transcript initiation 10 bp upstream of the P1 promoter transcript start point. Because of the overlap between P1 and P1A, P1A activity is unmasked only when the P1 promoter is inactivated by mutation. In the present paper, we report that mutation of the P1–10 element is less effective in unmasking P1A promoter activity than mutation of the P1–35 element. This suggests that the P1 promoter −35 element, which corresponds to the consensus, can sequester RNA polymerase even when P1 is inactive and thereby prevent RNA polymerase from serving the P1A promoter. We propose that such promoter elements may play a role in enforcing specificity in bacterial regulatory regions that contain alternative possible promoters