622 research outputs found

    In vivo investigation of interactions between replisome components in Escherichia coli: An expanded model for the processivity switch

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    Background: Protein interactions within the replisome (a highly coordinated protein complex) are crucial to maintain temporal and spatial regulation for high fidelity DNA synthesis in Escherichia coli (E. coli). A key component of these interactions is the processivity switch, ensuring smooth transition of the replicative DNA polymerase III (Pol III) between Okazaki fragments on the lagging strand. Multiple interaction studies between replisome components have been performed to indicate the essential roles of Pol III (DnaE), β-clamp, DnaB helicase, DNA and the t (DnaX) subunit for this switch.Methods: Known interacting regions of both DnaE and various truncated versions of t were chosen for co-expression in E. coli. Differences in the growth pattern of cells co-expressing various truncated versions of DnaX and DnaE, on liquid and solid media were subsequently analyzed. Based on in vivo analyses to explore the interactions between these components, an expanded model for the processivity switch is presented here.Results: The analyses suggest that residues 481-643 of t are sufficient to establish a functional interaction with the DnaB helicase and DnaE during replication, while residues 461-480 of t interact with the C-terminal tail of DnaE to disengage Pol III from the β-clamp during processivity switching. We also propose that residues 430-460 of t are involved in sensing the DNA structure required for the processivity switch.Conclusion: These observations expand the current understanding of processivity switching and help dissect the regions of t utilized for binding to different replisome components such as DnaB helicase, polymerase and DNA.Keywords: Processivity Switch; Clamp Loader; DnaE; DnaX; DnaB Helicas

    Organisational Learning and Incident Response: Promoting Effective Learning Through The Incident Response Process

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    Effective response to information security incidents is a critical function of modern organisations. However, recent studies have indicated that organisations have adopted a narrow and technical view of incident response (IR), focusing on the immediate concern of detection and subsequent corrective actions. Although some reflection on the IR process may be involved, it is typically limited to technical issues and does not leverage opportunities to learn about the organisational security threat environment and to adapt incident response capabilities. Given the science of incident response is rooted in practice, it is not surprising that the same criticisms can be applied to much of IR literature. However, a review of literature in the area of organisational learning suggests that improvements can be made to the incident response process. This paper proposes that future incident response research must incorporate a learning focus, improve feedback timing on learning activities, facilitate double-loop learning and incorporate an informal learning perspective within both formal, procedural incident response processes as well as unstructured, informal environments

    MOLECULAR ANALYSIS OF THE CAMP- RESPONSE ELEMENT [CRE] ELEMENTS IN THE PROMOTER REGION AND EXON 1 OF THE SURVIVAL OF MOTOR NEURON 2 [SMN2] GENE IN MALAYSIAN SPINAL MUSCULAR ATROPHY PATIENTS; TO ELUCIDATE THEIR ROLE IN CIRCUMSCRIBING THE CLINICAL SEVERITY

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    Objective: In the Spinal muscular atrophy [SMA] genes [SMN1 and SMN2 genes]; the CRE-II elements at -400 bp in the promoter region of the SMN genes and CRE-I element at +108 bp in the exon 1 of the SMN genes, are reported to have a role in c-AMP induce expression of the SMN genes through its binding affinity to CREB-1. This study was designed to determine the role of CRE sites in the circumscribing the clinical severity of SMA. Methods: Direct sequencing was performed for the PCR products of the promoter regions of the SMA patients with homozygous deletion of SMN1, different copy number of SMN2 and NAIP non deletion. Results: No variation among the CRE-I and CRE-II sites was found in all the clinical types as compare to normal healthy control showing no role of CRE sites in circumscribing the clinical severity of SMA. Conclusion: There was no sequence variation found in the CRE binding sites in the three different clinical types of SMA reflecting no role of CRE binding sites in circumscribing the clinical severity of SMA

    Towards Governance of Information Security Incident Response

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    Organizations are increasingly digitizing their business models to complement or even replace physical contact with customers and suppliers. With this shift online comes an increase in information security attacks, which are occurring more frequently due to the increased attack surface, vulnerabilities in security controls, and a target-rich environment. Organizations prevent attacks however some attacks are still successful and result in security incidents that degrade operations. When an organization is successfully breached, the organization must respond to the incident as quickly as possible to ensure continued operations and business resilience. However, guidance is lacking for governance of the response function. In a thematic review, we find good governance plays a key role in smooth and efficient incident response and this paper extends knowledge about governance of information security incident response by identifying key governance concepts that improve incident response efforts within organizations

    Information Security Strategy in Organisations: Review, Discussion and Future Research Directions

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    Dependence on information, including for some of the world’s largest organisations such as governments and multi-national corporations, has grown rapidly in recent years. However, reports of information security breaches and their associated consequences continue to indicate that attacks are still escalating on organisations when conducting these information-based activities. Clearly, more research is needed to better understand how organisations should formulate strategy to secure their information. Through a thematic review of academic security literature, we (1) analyse the antecedent conditions that motivate the potential adoption of a comprehensive information security strategy, (2) the current perspectives of strategy and (3) the yields and benefits that could be enjoyed post-adoption. Our contributions include a definition of information security strategy. We argue for a paradigm shift to extend from internally-focussed protection of organisation-wide information towards a strategic view that considers the inter-organisational level. Our findings are then used to suggest future research directions

    A Theory on Information Security

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    This paper proposes a theory on information security. We argue that information security is imperfectly understood and aim to bring about an altered understanding of why efforts are made to engage in information security. The goal of information security is widely recognised as the confidentiality, integrity and availability of information however we argue that the goal is actually to simply create resources. This paper responds to calls for more theory in information systems, places the discussion in philosophical context and compares various definitions. It then identifies the key concepts of information security, describes the relationships between these concepts, as well as scope and causal explanations. The paper provides the theoretical base for understanding why information is protected, in addition to theoretical and practical implications and suggestions for future research

    Molecular surveillance of HCV mono-infection and HCV-HBV co-infection in symptomatic population at Hyderabad, Pakistan

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    Background: Pakistan is endemic to hepatitis B and C infections. Alarming rise in hepatitis C virus (HCV) infection has been noticed in some areas of Sindh with an increasing risk for co-infection frequency in this region.Objective: To estimate the burden of HBV/HCV infection in Hyderabad Pakistan. Methods: ELISA and Nucleic acid Amplification test were performed to detect viruses. SPSS and online calculator were used for statistical analysis.Results: From a total of 108 seropositive hepatitis patients, 36.1% (n=39) were found HCV RNA-positive. Non-significant differences were observed in the frequencies of HCV infection for both genders [OR=0.735, CI (95%) 0.307-1.761, p<0.05]. The percentage of HBV DNA detection among 108 HCV-seropositive cases was 17.9% (n=19). However, HCV-HBV co-infection in HCV-RNA positive cases was determined in 48.7% (n=19) cases with non-significant difference in both genders [OR=1.51, CI (95%) = 0.38 - 5.96, p< 0.05]. Analysis suggested weakly positive correlation between HCV mono-infection and HCV-HBV co-infection and age (r =0.184, and r =0.1231), respectively.Conclusion: The study demonstrates a high prevalence of HBV co-infection among active hepatitis C patients of Hyderabad.Keywords: HCV mono-infection, HCV-HBV co-infection, molecular surveillance, Nucleic acid Amplification Test, active hepatitis C, Hyderabad, Sindh

    Pain patterns in patients with polycystic kidney disease

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    Pain patterns in patients with polycystic kidney disease.BackgroundPain is a common problem in patients with polycystic kidney disease (PKD), but patterns have not been characterized as to frequency and severity. Physicians should be aware of pain problems so an approach to chronic pain management can be pursued.MethodsOne hundred seventy-one completed questionnaires out of 300 distributed to PKD patients whose renal function ranged from normal to end-stage renal disease (ESRD) were analyzed. Age at diagnosis of PKD was documented, and patients noted how the diagnosis was made. Location, severity, and frequency of pain were characterized. The Visual Analogue Scale (VAS) was used to measure pain intensity.ResultsThere were 94 females and 77 male respondents, with a mean age of 47.4 years. Initial diagnosis of PKD occurred at a mean age of 31.6 years. Caucasians comprised 92.2% of the respondents. Patients' symptoms, a family history of PKD, and discovery of PKD during evaluation for hypertension or hematuria were the most frequent factors that led to the diagnosis. Order of frequency of pain was: low back pain, abdominal pain, headache, chest pain, and leg pain. Severity of pain, documented by the VAS intensity, was 4 to 5/10 in the majority of patients.ConclusionPain, which can be diffuse, is the most frequent symptom that led to the diagnosis of PKD in patients who responded to this questionnaire, and occurs with greater frequency than generally appreciated. Physicians need to obtain a detailed history about pain in their PKD population so as to allow an approach to pain management

    Transesterification of Jatropha curcas Seed Oil: Reaction Parameters

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         This study was carried out to determine the reaction parameters of the fatty acid methyl ester (FAME) and yield produced from Jatropha curcas (J. curcas) oil by alkali transesterification. Optimum reaction parameters were observed at 1:6 w/w methanol to oil ratio, 0.5% w/w NaOH to oil molar ratio, 400 rpm agitation speed and 60 ⁰C with resulted in a yield of 99% crude biodiesel and 97.71% FAME
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