Publications by authors named "Peter J O"

6 Publications

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Root Exudates Alter the Expression of Diverse Metabolic, Transport, Regulatory, and Stress Response Genes in Rhizosphere .

Front Microbiol 2021 14;12:651282. Epub 2021 Apr 14.

School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States.

Plants live in association with microorganisms that positively influence plant development, vigor, and fitness in response to pathogens and abiotic stressors. The bulk of the plant microbiome is concentrated belowground at the plant root-soil interface. Plant roots secrete carbon-rich rhizodeposits containing primary and secondary low molecular weight metabolites, lysates, and mucilages. These exudates provide nutrients for soil microorganisms and modulate their affinity to host plants, but molecular details of this process are largely unresolved. We addressed this gap by focusing on the molecular dialog between eight well-characterized beneficial strains of the group and , a model for economically important food, feed, forage, and biomass crops of the grass family. We collected and analyzed root exudates of and demonstrated the presence of multiple carbohydrates, amino acids, organic acids, and phenolic compounds. The subsequent screening of bacteria by Biolog Phenotype MicroArrays revealed that many of these metabolites provide carbon and energy for the strains. RNA-seq profiling of bacterial cultures amended with root exudates revealed changes in the expression of genes encoding numerous catabolic and anabolic enzymes, transporters, transcriptional regulators, stress response, and conserved hypothetical proteins. Almost half of the differentially expressed genes mapped to the variable part of the strains' pangenome, reflecting the importance of the variable gene content in the adaptation of to the rhizosphere lifestyle. Our results collectively reveal the diversity of cellular pathways and physiological responses underlying the establishment of mutualistic interactions between these beneficial rhizobacteria and their plant hosts.
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http://dx.doi.org/10.3389/fmicb.2021.651282DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079746PMC
April 2021

May Measurement Month 2018: an analysis of blood pressure screening results from Nigeria.

Eur Heart J Suppl 2020 Aug 28;22(Suppl H):H96-H99. Epub 2020 Aug 28.

Department of Medicine, University of Ilorin, Old Jebba Road, Ilorin 240003, Nigeria.

Hypertension remains the dominant cardiovascular risk factor worldwide. May Measurement Month (MMM) is an annual global programme of the International Society of Hypertension aimed at screening for undetected hypertension in the general population. We report the outcome of MMM 2018 in Nigeria. An opportunistic screening of adults aged at least 18 years was conducted in the six geopolitical zones of Nigeria in the month of May, 2018. Screening for hypertension was done by trained volunteers with the use of validated digital and mercury sphygmomanometers following the MMM protocol. Hypertension was defined as blood pressure (BP) ≥140/90 mmHg or the use of BP-lowering medication. There were 6398 participants (53.0% female) with a mean (SD) age of 41.7 (15.0) years. Hypertension was present in 36.4% of the participants with 51.1% of the hypertensives aware of their status, 41.8% on medication, of whom 43.1% were controlled. Overall, only 18.0% of all hypertensive participants had their BP under control. The proportion with hypertension is high, and awareness, treatment, and control rates are low. Concerted efforts are needed to improve awareness and treatment of hypertension in Nigeria in order to reduce the high rate of complications associated with uncontrolled BP.
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http://dx.doi.org/10.1093/eurheartj/suaa038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7455261PMC
August 2020

Differential hnRNP D isoform incorporation may confer plasticity to the ESSV-mediated repressive state across HIV-1 exon 3.

Biochim Biophys Acta Gene Regul Mech 2017 Feb 3;1860(2):205-217. Epub 2016 Dec 3.

Institute of Virology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany; Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany. Electronic address:

Even though splicing repression by hnRNP complexes bound to exonic sequences is well-documented, the responsible effector domains of hnRNP proteins have been described for only a select number of hnRNP constituents. Thus, there is only limited information available for possible varying silencer activities amongst different hnRNP proteins and composition changes within possible hnRNP complex assemblies. In this study, we identified the glycine-rich domain (GRD) of hnRNP proteins as a unifying feature in splice site repression. We also show that all four hnRNP D isoforms can act as genuine splicing repressors when bound to exonic positions. The presence of an extended GRD, however, seemed to potentiate the hnRNP D silencer activity of isoforms p42 and p45. Moreover, we demonstrate that hnRNP D proteins associate with the HIV-1 ESSV silencer complex, probably through direct recognition of "UUAG" sequences overlapping with the previously described "UAGG" motifs bound by hnRNP A1. Consequently, this spatial proximity seems to cause mutual interference between hnRNP A1 and hnRNP D. This interplay between hnRNP A1 and D facilitates a dynamic regulation of the repressive state of HIV-1 exon 3 which manifests as fluctuating relative levels of spliced vpr- and unspliced gag/pol-mRNAs.
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http://dx.doi.org/10.1016/j.bbagrm.2016.12.001DOI Listing
February 2017

Genomic HEXploring allows landscaping of novel potential splicing regulatory elements.

Nucleic Acids Res 2014 21;42(16):10681-97. Epub 2014 Aug 21.

Institute for Virology, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany

Effective splice site selection is critically controlled by flanking splicing regulatory elements (SREs) that can enhance or repress splice site use. Although several computational algorithms currently identify a multitude of potential SRE motifs, their predictive power with respect to mutation effects is limited. Following a RESCUE-type approach, we defined a hexamer-based 'HEXplorer score' as average Z-score of all six hexamers overlapping with a given nucleotide in an arbitrary genomic sequence. Plotted along genomic regions, HEXplorer score profiles varied slowly in the vicinity of splice sites. They reflected the respective splice enhancing and silencing properties of splice site neighborhoods beyond the identification of single dedicated SRE motifs. In particular, HEXplorer score differences between mutant and reference sequences faithfully represented exonic mutation effects on splice site usage. Using the HIV-1 pre-mRNA as a model system highly dependent on SREs, we found an excellent correlation in 29 mutations between splicing activity and HEXplorer score. We successfully predicted and confirmed five novel SREs and optimized mutations inactivating a known silencer. The HEXplorer score allowed landscaping of splicing regulatory regions, provided a quantitative measure of mutation effects on splice enhancing and silencing properties and permitted calculation of the mutationally most effective nucleotide.
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http://dx.doi.org/10.1093/nar/gku736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4176321PMC
January 2015

Spectrum of Echocardiographic Abnormalities among 168 Consecutive Referrals to an Urban Private Hospital in South-Western Nigeria.

Clin Med Insights Cardiol 2014 31;8:35-8. Epub 2014 Mar 31.

Department of Medicine, Ladoke Akintola University Teaching Hospital, Osogbo, Nigeria.

Trans-thoracic echocardiography (TTE) is an important non-invasive cardiac examination that provides structural and functional information. It is useful in the diagnosis of cardiac diseases and often guides the management and follow-up of patients with cardiovascular diseases (CVD). The study aimed to present an audit of the echocardiograms performed in an urban private hospital over a two-year period in order to define the pattern of cardiac diseases in our center. Echocardiogram reports of 168 consecutive patients performed between May 2011 and April 2013 at an organized private sector hospital in Lagos, south-west Nigeria were reviewed. Studies were performed with a Toshiba Nemio XG ultrasound machine. The data obtained were analyzed for mean age, sex, clinical indications, and echocardiographic diagnosis in the study subjects. A total of 168 echocardiography reports were examined, comprising of 92 males (54.8%) and 76 females (45.2%). The age range of the subjects was 10-76 years (mean 42.5 ± 12.1 years). The commonest indication for echocardiography was systemic hypertension and hypertension related causes (38.1%), followed by abnormal resting electrocardiogram (14.9%). Routine annual medical screening was the next most common indication, representing 13.1% of the indications for echocardiography. The other indications are as presented in Table 1. The echocardiogram was normal in 64.3% of the subjects. The commonest abnormality detected was hypertensive heart disease (HHD); accounting for 9.6% of the subjects studied. Isolated atrial enlargement (left, right, or bi-atrial) was the next most common abnormality accounting for 6% of the echocardiographic diagnosis. Pulmonary hypertension was the next most common diagnosis accounting for 4.8% of our findings. The other echocardiographic diagnoses are as listed in Table 2. Hypertension represents the commonest indication for echocardiography. Normal echocardiogram was the commonest echocardiographic finding while HHD was the commonest echocardiographic abnormality. The prevalence of ischemic heart disease by echocardiography was 2.4%. There was no case of rheumatic heart disease (RHD). The prevalence of hypertrophic cardiomyopathy (HCM) was 1.2%. Ease of access to echocardiography may influence the findings in an echocardiographic audit and policy makers should incorporate appropriateness criteria into their guidelines for reimbursement.
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http://dx.doi.org/10.4137/CMC.S14320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3972076PMC
April 2014

The new face of rheumatic heart disease in South West Nigeria.

Int J Gen Med 2013 23;6:375-81. Epub 2013 May 23.

Department of Medicine, College of Health Sciences, Osun State University, Osogbo, Osun State, Nigeria ; Department of Medicine, LAUTECH Teaching Hospital, Osogbo, Osun State, Nigeria.

Purpose: To determine the current prevalence of rheumatic heart disease (RHD), clinical features, types of valvular lesions, complications and mortality, at Ladoke Akintola University of Technology (LAUTECH) Teaching Hospital, Osogbo, South West Nigeria.

Methods: We conducted a retrospective, descriptive study of all the cases of RHD seen in the medical outpatient clinics and wards of LAUTECH for 9 years, from January 2003 to December 2011. Statistical analysis of data obtained was done using SPSS 16.

Results: The total number of attendees of all the medical outpatient clinics during the 9-year period was 67,378, with a subset of 9423 attending the cardiology clinic. There were 11 cases of RHD, which translates to a prevalence of 0.16/1000 and 1.2/1000 for medical outpatient clinics and the cardiology clinic respectively. The mean age of the patients was 25.64 ± 9.65 years, age range 14-40 years and male to female ratio of 1:1.2. The most common valve affected was mitral (90.9%), followed by the aortic (36.4%), and the tricuspid (18.2%). Mitral and aortic lesions coexisted in 18.2% of the patients, and late presentation was common in all RHD cases. Heart failure was the most common complication (90.9%). Other complications were secondary pulmonary hypertension (36.4%), infective endocarditis (27.3%), atrial fibrillation (27.3%), cardioembolic cerebrovascular disease (18.2%), and atrial flutter (9.1%). Mortality was 9.1%, while only one patient (9.1%) had definitive surgery. Financial constraints precluded others from having definitive surgery.

Conclusion: The prevalence of RHD has declined considerably as a result of improvements in the primary health care delivery system, with widespread use of appropriate antibiotic therapy for sore throats resulting in the prevention of rheumatic fever and RHD. However, late presentation is still very common, hence we advocate a more aggressive drive to make the Drakensberg declaration on the control of rheumatic fever and rheumatic heart disease functional in our practice area.
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http://dx.doi.org/10.2147/IJGM.S44289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666550PMC
June 2013
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