24 results on '"Unachukwu N"'
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2. Attitudes and Practices of Insecticide Treated Bed Nets Usage among Rural Dwellers in Oyo State, Nigeria
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Ekeleme, N. C., primary, Ijioma, C. E., additional, Unachukwu, N. A., additional, Ejikem, P. I., additional, Areh, J. E., additional, Ogwu, C. I., additional, Jeffery, E. O., additional, Esangbedo, I. J., additional, Amuta, A. C., additional, Ojiri, P. C., additional, Amoji, N. O., additional, Aminu-Ayinde, O. E., additional, Amadi, E. S., additional, Onyeukwu, N., additional, Abali, I. O., additional, and Airaodion, A. I., additional
- Published
- 2023
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3. Classification of elite cassava varieties (Manihot esculenta Crantz) cultivated in Benin Republic using farmers’ knowledge, morphological traits and simple sequence repeat (SSR) markers
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Agre, A. P., Bhattacharjee, R., Rabbi, I. Y., Alaba, O. A., Unachukwu, N. N., Ayenan, M. A. T., Loko, Y. L., Bauchet, G. J., and Dansi, A.
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- 2017
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4. Neuroendocrine tumors and Survival- a meta-analysis
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Khayyat, A, primary, Asad, M, additional, Aslam, A, additional, Rabbani, R, additional, Fabara, S, additional, Chandramohan, S, additional, Unachukwu, N, additional, Nasyrlaeva, B, additional, Chowdary, S, additional, Hammoud, G, additional, and Jaiswal, R, additional
- Published
- 2021
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5. Assessment of genetic diversity of selected cowpea landraces from Nigeria based on simple sequence repeat markers
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Iseghohi, I.O., primary, Adesoye, A.I., additional, Oludare, D.A., additional, Agunbiade, F.V., additional, and Unachukwu, N., additional
- Published
- 2020
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6. Effect of storage environment on carrot root rots and biochemical changes during storage
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Odebode, A. C. and Unachukwu, N. E.
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- 1997
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7. Transcriptome analysis oF a tropical maize inbred line reveals a NOVEL mechanism of tolerance to Striga hermonthica
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Marcotrigiano A. R., Unachukwu N., Reehemat O.S., Abdulsalam T., Gedil M., Menkir A., Gisel A., Ricciardi L., and Stavolone L.
- Subjects
no key words - Abstract
Maize is a major staple cereal in sub-Saharan Africa. Its cultivation is highly affected by the parasitic weed Striga hermonthica, an important biotic constraint to production in Africa. Considerable efforts have been invested in breeding for Striga resistance in cereals, however, the level of protection achieved to date is incomplete and the resistance is mainly determined by the coexistence of several mechanisms controlled by multigenic and quantitative systems. A maize inbred line (ZD05) showing significant tolerance to the Striga parasite was previously identified at the International Institute of Tropical Agriculture (IITA) in Nigeria but the underlying mechanisms of resistance is yet unknown. To gain insights into the molecular basis of such resistance, we performed RNAseq profiling of the tolerant (ZD05) and a susceptible (5057) maize genotype, both infested (I) and un-infested (U) with Striga hermontica, and at three different time points. Transcriptome analysis revealed that the resistance reaction was characterized by differential expression of genes involved in cell wall rearrangement and in secondary metabolism. Unexpectedly, we also detected differential regulation of genes involved in the hydroxamic acids pathway (DIMBOA). To assess the allelophatic effects of hydroxamic acids against Striga, in the susceptible and the tolerant maize inbred lines, we performed biological quantitative tests of root extracts under different experimental conditions. The level of parasitization resulted correlate to the DIMBOA content in roots subject to different treatments, and the resistant line showed higher concentration of this compound compared to susceptible line. Furthemore, in vitro striga seed germination was depleted upon increasing concentrations of DIMBOA. Finally, the expression levels of candidate genes, was confirmed by quantitative real-time PCR in an independent experiment. These results suggest that ZD05 resists to Striga infection using multiple biochemical and physiological mechanisms implying that the resistance is likely polygenic. The importance of the DIMBOA pathway in the mechanism of resistance to Striga in maize is being confirmed by loss-of-function experiments.
- Published
- 2019
8. Genetic diversity and population structure of Striga hermonthica populations from Kenya and Nigeria
- Author
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Unachukwu, N N, primary, Menkir, A, additional, Rabbi, I Y, additional, Oluoch, M, additional, Muranaka, S, additional, Elzein, A, additional, Odhiambo, G, additional, Farombi, E O, additional, and Gedil, M, additional
- Published
- 2017
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9. The Effect of Smart Government on Governance in Covid-19 Era
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Unachukwu Nnedi Obianuju, Mercy Ejovwokeoghene Ogbari, and George Uzoma K. Chima
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smart city ,smart government ,smart governance ,citizen centricity ,efficiency. ,Political science ,Social Sciences - Abstract
The research work looked at the relationship between various dimensions of smart government which are citizen centricity, efficiency, effectiveness and the dimensions of smart governance being strategic dimension, networking and collaboration between institutions. This study made use of a quantitative analytical cross-sectional design. The study made use of the Stakeholder theory. It also made use of the purposive, convenience and simple random sampling technique. A survey was designed for the respondents which was inclusive of one hundred and thirty (130) postgraduate students of Covenant University, Ota, Ogun state and the Statistical package for social sciences was used in running the analysis. According to the findings of this study, smart government could be regarded a foundation for establishing governance by utilizing advanced information and technology for good governance, which is characterized by multiple interrelationships between individuals, government and other decision makers. The sample size and analyses focused majorly on the Postgraduate students of Covenant University. From the findings, the students assert that the governments use of ICT platforms has been able to enhance the resilience of the government and organisations as they have been able to develop a means to cope, adapt and adjust to this global change. The efficient and effective use of ICT, allowed for networking and collaborative interaction between government and other state and the governments and organizations. This implies that governments ability to take smart and strategic actions in the face of unforeseen and unpredictable challenges through the use of ICT has proven a candid means for the government to efficiently and effectively run any nation state. The findings focus on examining the effect of smart government on governance. The paper is significant in giving insightful directives on the realities of running government in a continuous dynamic environment which factors are unpredictable and gives a guide on how government should be run in the face of untold challenges.
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- 2022
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10. Classification of elite cassava varieties (<italic>Manihot esculenta</italic> Crantz) cultivated in Benin Republic using farmers’ knowledge, morphological traits and simple sequence repeat (SSR) markers.
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Agre, A. P., Bhattacharjee, R., Rabbi, I. Y., Alaba, O. A., Unachukwu, N. N., Ayenan, M. A. T., Loko, Y. L., Bauchet, G. J., and Dansi, A.
- Abstract
Cassava (
Manihot esculenta Crantz) is an important food security crop or resource for poor rural communities particularly in Africa. The crop’s ability to produce high yields even under poor conditions and storability of its roots underground for longer periods or until needed makes it a model ‘food security crop’. In Benin Republic, cassava has been recognized as one of the major crop contributing towards dynamic value chains generating incomes for small-holder farmers. The crop is grown all over the country, however, the increased production are mainly recorded from far south and central parts of the country. Genetic improvement of cassava in Benin Republic is limited because of poor knowledge of genetic diversity present within the country. The main objective of this study was to assess the genetic diversity and relationships among elite cassava varieties collected from different regions of Benin using fluorescently labelled simple sequence repeat (SSR) markers and to compare the results with farmer’s knowledge and morphological traits. A total of 96 cultivars collected from major cassava growing areas such as Southern and Central Benin were classified into 24 different groups using farmers’ knowledge, while classification based on 18 morphological traits resulted in five groups. In total, sixteen SSR markers were tested for molecular analysis of the ninety-six cassava varieties. Among the sixteen, twelve SSR markers gave good banding pattern and were used to genotype the varieties. An average of 3.58 and 0.47 for number of alleles and polymorphism information content respectively was observed. The observed heterozygosity (Ho ) ranged from 0.23 to 1.0 with an average of 0.66 indicating moderate level of diversity among the cultivars. Based on the proportion of shared alleles and hierarchical clustering, the 96 elite cassava varieties were classified as 74 unique varieties. Principal component analysis and analysis of molecular variance revealed no significant variation between the regions thus, explaining regular exchange of planting materials among cassava farmers across various regions. The moderate level of genetic diversity in famer’s field, revealed in the present study, is a good indication of the need for broadening the genetic base of cassava in Benin Republic and establishing a formal breeding program in the country. [ABSTRACT FROM AUTHOR]- Published
- 2018
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11. Approaches and progress in breeding drought-tolerant maize hybrids for tropical lowlands in west and central Africa.
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Menkir A, Dieng I, Gedil M, Mengesha W, Oyekunle M, Riberio PF, Adu GB, Yacoubou AM, Coulibaly M, Bankole FA, Derera J, Bossey B, Unachukwu N, Ilesanmi Y, and Meseka S
- Subjects
- Africa, Central, Africa, Western, Tropical Climate, Adaptation, Physiological genetics, Hybridization, Genetic, Zea mays genetics, Zea mays physiology, Droughts, Plant Breeding
- Abstract
Drought represents a significant production challenge to maize farmers in West and Central Africa, causing substantial economic losses. Breeders at the International Institute of Tropical Agriculture have therefore been developing drought-tolerant maize varieties to attain high grain yields in rainfed maize production zones. The present review provides a historical overview of the approaches used and progress made in developing drought-tolerant hybrids over the years. Breeders made a shift from a wide area testing approach, to the use of managed screening sites, to precisely control the intensity, and timing of drought stress for developing drought-tolerant maize varieties. These sites coupled with the use of molecular markers allowed choosing suitable donors with drought-adaptive alleles for integration into existing elite maize lines to generate new drought-tolerant inbred lines. These elite maize inbred lines have then been used to develop hybrids with enhanced tolerance to drought. Genetic gains estimates were made using performance data of drought-tolerant maize hybrids evaluated in regional trials for 11 years under managed drought stress, well-watered conditions, and across diverse rainfed environments. The results found significant linear annual yield gains of 32.72 kg ha
-1 under managed drought stress, 38.29 kg ha-1 under well-watered conditions, and 66.57 kg ha-1 across multiple rainfed field environments. Promising hybrids that deliver high grain yields were also identified for areas affected by drought and variable rainfed growing conditions. The significant genetic correlations found among the three growing conditions highlight the potential to exploit the available genetic resources and modern tools to further enhance tolerance to drought in hybrids., (© 2024 International Institute of Tropical Agriculture. The Plant Genome published by Wiley Periodicals LLC on behalf of Crop Science Society of America.)- Published
- 2024
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12. Hydroxamic acids: New players in the multifactorial mechanisms of maize resistance to Striga hermonthica.
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Marcotrigiano AR, Carluccio AV, Unachukwu N, Adeoti SR, Abdulsalam T, Gedil M, Menkir A, Gisel A, and Stavolone L
- Subjects
- Zea mays genetics, Plant Breeding, Crops, Agricultural, Down-Regulation, Striga genetics
- Abstract
Striga hermonthica is the most widespread and destructive plant parasite infesting maize and other major crops in sub-Saharan Africa where it causes severe yield losses and threatens food security. Several tolerant maize lines supporting reduced S. hermonthica emergence have been deployed. However, the molecular bases of such resistance are yet poorly understood. Based on a time course comparative gene expression analysis between susceptible and resistant maize lines we have confirmed resistance mechanisms known to be activated upon plant parasite infestation and identified potential novel players worth further investigation e.g. iron homeostasis and mitochondrial respiration-related genes. Most intriguingly, we show a previously unknown strategy of maize post-attachment resistance based on DIMBOA accumulation in S. hermonthica-infested maize roots. S. hermonthica infestation triggers positive regulation of gene expression in the hydroxamic acid (HA) pathway culminating with an accumulation of benzoxazinoids (BX), known for their antifeedant, insecticidal, antimicrobial, and allelopathic activities. We demonstrate that HA root content is positively correlated with S. hermonthica resistance in the resistant parent and its progenies and in unrelated maize lines. Downregulation of HA genes causes increased susceptibility to S. hermonthica infestation in loss-of-function maize mutants. While the mechanism of BX action in parasitic plant resistance is yet to be uncovered, the potential of this discovery for developing effective control and breeding strategies is enormous., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)
- Published
- 2023
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13. Revascularization Modalities in Acute Coronary Syndrome: A Review of the Current State of Evidence.
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Surve TA, Kazim MA, Sughra M, Mirza AMW, Murugan SK, Shebani KAM, Karishma F, Trada IJ, Mansour M, Asif K, Kaur L, Kamal A, Unachukwu N, and Naveed A
- Abstract
Acute coronary syndrome (ACS) stands as a leading global cause of mortality, underscoring the importance of effective prevention, early diagnosis, and timely intervention. While medications offer benefits to many patients, revascularization procedures such as coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), and emerging hybrid approaches remain pivotal for ACS management. This review delves into the 2018 ESC/EACTS guidelines alongside an analysis of existing literature to shed light on the spectrum of revascularization methods. While both CABG and PCI demonstrate promising outcomes, the optimal choice between the two hinges on a comprehensive assessment of individual patient factors, anatomical complexity guided by advanced imaging, comorbidities, and age. The determination of whether to pursue culprit or total revascularization, as well as immediate or staged revascularization, is contingent upon various factors, including age, disease complexity, and clinical outcomes. This evidence-based decision-making process is orchestrated by a multidisciplinary heart team grounded in ongoing clinical evaluation. The primary objective of this review is to provide valuable insights into revascularization strategies and scrutinize the congruence of current guidelines with recent advancements in the field., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Surve et al.)
- Published
- 2023
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14. Heterotic grouping of provitamin A-enriched maize inbred lines for increased provitamin A content in hybrids.
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Maazou AS, Gedil M, Adetimirin VO, Unachukwu N, Mengesha W, Meseka S, and Menkir A
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- Plant Breeding, Academies and Institutes, Agriculture, Edible Grain, Zea mays genetics, Provitamins
- Abstract
Background: The establishment of heterotic groups of inbred lines is crucial for hybrid maize breeding programs. Currently, there is no information on the heterotic patterns of the Provitamin A (PVA) inbred lines developed in the maize improvement program of the International Institute of Tropical Agriculture (IITA) to form productive PVA enriched hybrids for areas affected by vitamin A deficiency. This study assessed the feasibility of classifying PVA-enriched inbred lines into heterotic groups based on PVA content without compromising grain yield in hybrids. Sixty PVA inbred lines were crossed to two testers representing two existing heterotic groups. The resulting 120 testcrosses hybrids were evaluated for two years at four locations in Nigeria., Results: The two testers effectively classified the inbred lines into two heterotic groups. The PVA-based general combining ability and specific combining ability (HSGCA) method assigned 31 and 27 PVA enriched maize inbred lines into HGB and HGA, respectively, leaving two inbred lines not assigned to any group. The yield-based HSGCA method classified 32 inbred lines into HGB and 28 inbred lines into HGA. Both PVA and yield-based heterotic grouping methods assigned more than 40% of the inbred lines into the same heterotic groups. Even though both PVA and yield-based heterotic grouping of the inbred lines differed from the clusters defined by the DArTag SNP markers, more than 40% of the inbred lines assigned to HGA were present in Cluster-1 and 60% of the inbred lines assigned to HGB were present in Cluster-3. Interestingly, the inbred lines assigned to the same heterotic groups based on PVA content and grain yield were distributed across the three Ward's clusters. The PVA-based HSGCA was identified as the most effective heterotic grouping method for breeding programs working on PVA biofortification., Conclusions: Selecting PVA enriched maize inbred lines with diverse genetic backgrounds from the three marker-based clusters may facilitate the development of productive hybrids with high PVA content and for generating source populations to develop more vigorous maize inbred lines with much higher concentrations of PVA., (© 2023. The Author(s).)
- Published
- 2023
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15. Author Correction: Genetic structure analysis and identifying key founder inbred lines in diverse elite sub-tropical maize inbred lines.
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Gedil M, Maazou AS, Zebire DA, Garcia-Oliveira AL, Unachukwu N, Petroli C, Hearne S, Everett LA, Kim SK, and Menkir A
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- 2023
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16. Genetic structure analysis and identifying key founder inbred lines in diverse elite sub-tropical maize inbred lines.
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Gedil M, Maazou AS, Zebire DA, Garcia-Oliveira AL, Unachukwu N, Petroli C, Hearne S, Everett LA, Kim SK, and Menkir A
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- Provitamins, Plant Breeding, Phenotype, Genetic Variation, Zea mays genetics, Polymorphism, Single Nucleotide
- Abstract
Understanding the genetic relationships between the key founder inbred lines and derived inbred lines could provide insight into the breeding history and the structure of genetic diversity of the available elite inbred lines with desirable target traits. The maize improvement program at the International Institute of Tropical Agriculture (IITA) analyzed the pedigree information of 623 sub-tropical maize inbred lines generated at the IITA maize breeding program to identify the key founder inbred lines. We also used 5032 SNP markers to assess the genetic similarities of the founder inbred lines with their progenies subsequently developed for specific target traits. The results of pedigree analysis and SNP markers-based similarity scores identified 20 key founder inbred lines with significant contributions to the development of drought tolerant, early maturing, productive, Striga resistant, provitamin A enriched, and quality protein maize inbred lines. In our breeding program, line TZMi501 belonging to a flint heterotic group (HGA), and TZMi407-S and TZMi214, representing the dent heterotic group (HGB), were identified as the most useful founder inbred lines. The 623 inbred lines were consistently separated into four clusters based on Ward's hierarchical clustering, structure, and principal component analyses, with the 20 founder inbred lines spread into all clusters. The founder inbred lines were more genetically related to the productive inbred lines but showed genetic divergence from the provitamin A enriched inbred lines. These results provide a better understanding of the breeding history of the sub-tropical maize inbred lines to facilitate parental selection aligned to existing heterotic groups for use in breeding programs targeting the improvement of essential traits in maize., (© 2023. The Author(s).)
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- 2023
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17. Association of Smoking and E-Cigarette in Chronic Liver Disease: An NHANES Study.
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Chakinala RC, Dawoodi S, Fabara SP, Asad M, Khayyat A, Chandramohan S, Aslam A, Unachukwu N, Nasyrlaeva B, Jaiswal R, Chowdary SB, Malik P, and Rabbani R
- Abstract
Background: There is an increased trend of e-cigarette but the toxic effects of e-cigarette metabolites are not widely studied especially in liver disease. Hence, we aimed to evaluate the prevalence and patterns of recent e-cigarette use in a nationally representative sample of US adults and adolescents and its association amongst respondents with liver disease., Methods: We conducted a retrospective cross-sectional study using National Health and Nutrition Examination Survey (NHANES) database from 2015 to 2018. The self-reported NHANES questionnaire was used to assess liver disease (MCQ160L, MCQ170L and MCQ 510 (a-e)), e-cigarette use (SMQ900) and traditional smoking status (SMQ020 or SMQ040). We conducted univariate analysis and multivariable logistic regression models to predict the association of e-cigarette use, traditional smoking and dual smoking amongst the population with liver disease., Results: Out of total 178,300 respondents, 7,756 (4.35%) were e-cigarette users, 48,625 (27.27%) traditional smoking, 23,444 (13.15%) dual smoking and 98,475 (55.23%) non-smokers. Females had a higher frequency of e-cigarette use (49.3%) compared to dual (43%) and traditional smoking (40.8%) (P < 0.0001). Respondents with a past history of any liver disease have lower frequency of e-cigarette use compared to dual and traditional smoking, respectively (2.4% vs. 6.4% vs. 7.2%; P < 0.0001). In multivariate logistic regression models, we found that e-cigarette users (odds ratio (OR): 1.06; 95% confidence interval (CI): 1.05 - 1.06; P < 0.0001) and dual smoking (OR: 1.50; 95% CI: 1.50 - 1.51; P < 0.0001) were associated with higher odds of having history of liver disease compared to non-smokers., Conclusion: Our study found that despite the low frequency of e-cigarette use in respondents with liver disease, there was higher odds of e-cigarette use amongst patients with liver disease. This warrants the need for more future prospective studies to evaluate the long-term effects and precise mechanisms of e-cigarette toxicants on the liver., Competing Interests: The authors declare no conflict of interest., (Copyright 2022, Chakinala et al.)
- Published
- 2022
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18. Cardiac Sarcoidosis Diagnostic Challenges and Management: A Case Report and Literature Review.
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Jaiswal R, Vaisyambath L, Khayyat A, Unachukwu N, Nasyrlaeva B, Asad M, Fabara SP, Balan I, Kolla S, and Rabbani R
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Sarcoidosis can be presented as cardiac sarcoidosis (CS), which is challenging to diagnose due to its clinical silence. Ventricular arrhythmias and atrioventricular blocks can be fatal and cause sudden death in patients with cardiac sarcoidosis. Five percent of sarcoidosis patients have clinically evident cardiac sarcoidosis. However, autopsy reports and imaging studies have shown a higher prevalence of cardiac involvement. Early recognition is important to prevent such detrimental consequences. Cardiac sarcoidosis is increasingly being diagnosed owing to increased awareness among physicians and new diagnostic tools like MRI and positron emission tomography (PET) scan replacing traditional endomyocardial biopsy. A definitive diagnosis of CS remains challenging due to the non-specific clinical findings that can present similar symptoms of common cardiac disease; therefore, the imaging and biopsies are substantial for diagnosis confirmation. Pharmacological and Implantable devices are two main therapeutic approaches in cardiac sarcoidosis, in which steroids and pacemaker therapy have shown better outcomes. This review summarizes the available data related to the prevalence, prognosis, diagnosis, and management of cardiac sarcoidosis., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Jaiswal et al.)
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- 2022
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19. Genetic diversity and population structure of an African yam bean (Sphenostylis stenocarpa) collection from IITA GenBank.
- Author
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Shitta NS, Unachukwu N, Edemodu AC, Abebe AT, Oselebe HO, and Abtew WG
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- Africa South of the Sahara, Agriculture, Databases, Nucleic Acid, Genetic Variation, Plant Breeding, Polymorphism, Single Nucleotide, Sphenostylis chemistry
- Abstract
African yam bean, AYB (Sphenostylis stenocarpa), is an underutilized legume of tropical Africa. AYB can boost food and nutritional security in sub-Saharan Africa through its nutrient-rich seeds and tubers. However, inadequate information on germplasm with desirable agro-morphological traits, including insufficient data at the genomic level, has prevented the full exploitation of its food and breeding potentials. Notably, assessing the genetic diversity and population structure in a species is a prerequisite for improvement and eventual successful exploitation. The present study evaluated the population structure and genetic diversity of 169 accessions from the International Institute of Tropical Agriculture (IITA) collection using 26 phenotypic characters and 1789 single nucleotide polymorphism (SNP) markers. The phenotypic traits and SNP markers revealed their usefulness in uniquely distinguishing each AYB accession. The hierarchical cluster of phenotypes grouped accessions into three sub-populations; SNPs analysis also clustered the accessions into three sub-populations. The genetic differentiation (F
ST ) among the three sub-populations was sufficiently high (0.14-0.39) and significant at P = 0.001. The combined analysis revealed three sub-populations; accessions in sub-population 1 were high yielding, members in sub-population 2 showed high polymorphic loci and heterozygosity. This study provides essential information for the breeding and genetic improvement of AYB., (© 2022. The Author(s).)- Published
- 2022
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20. Genetic Diversity and Population Structure of Cowpea [ Vigna unguiculata (L.) Walp.] Germplasm Collected from Togo Based on DArT Markers.
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Gbedevi KM, Boukar O, Ishikawa H, Abe A, Ongom PO, Unachukwu N, Rabbi I, and Fatokun C
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- Phylogeny, Polymorphism, Single Nucleotide, Seed Bank, Togo, Genetic Variation, Genetics, Population, Vigna genetics
- Abstract
Crop genetic diversity is a sine qua non for continuous progress in the development of improved varieties, hence the need for germplasm collection, conservation and characterization. Over the years, cowpea has contributed immensely to the nutrition and economic life of the people in Togo. However, the bulk of varieties grown by farmers are landraces due to the absence of any serious genetic improvement activity on cowpea in the country. In this study, the genetic diversity and population structure of 255 cowpea accessions collected from five administrative regions and the agricultural research institute of Togo were assessed using 4600 informative diversity array technology (DArT) markers. Among the regions, the polymorphic information content (PIC) ranged from 0.19 to 0.27 with a mean value of 0.25. The expected heterozygosity (He) varied from 0.22 to 0.34 with a mean value of 0.31, while the observed heterozygosity (Ho) varied from 0.03 to 0.07 with an average of 0.05. The average inbreeding coefficient (F
IS ) varied from 0.78 to 0.89 with a mean value of 0.83, suggesting that most of the accessions are inbred. Cluster analysis and population structure identified four groups with each comprising accessions from the six different sources. Weak to moderate differentiation was observed among the populations with a genetic differentiation index varying from 0.014 to 0.117. Variation was highest (78%) among accessions within populations and lowest between populations (7%). These results revealed a moderate level of diversity among the Togo cowpea germplasm. The findings of this study constitute a foundation for genetic improvement of cowpea in Togo., Competing Interests: The authors declare no conflicts of interest.- Published
- 2021
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21. Genetic Diversity and Population Structure of Maize Inbred Lines with Varying Levels of Resistance to Striga Hermonthica Using Agronomic Trait-Based and SNP Markers.
- Author
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Stanley A, Menkir A, Paterne A, Ifie B, Tongoona P, Unachukwu N, Meseka S, Mengesha W, and Gedil M
- Abstract
Striga hermonthica is a serious biotic stress limiting maize production in sub-Saharan Africa. The limited information on the patterns of genetic diversity among maize inbred lines derived from source germplasm with mixed genetic backgrounds limits the development of inbred lines, hybrids, and synthetics with durable resistance to S. hermonthica . This study was conducted to assess the level of genetic diversity in a panel of 150 diverse maize inbred lines using agronomic and molecular data and also to infer the population structure among the inbred lines. Ten Striga -resistance-related traits were used for the phenotypic characterization, and 16,735 high-quality single-nucleotide polymorphisms (SNPs), identified by genotyping-by-sequencing (GBS), were used for molecular diversity. The phenotypic and molecular hierarchical cluster analyses grouped the inbred lines into five clusters, respectively. However, the grouping patterns between the phenotypic and molecular hierarchical cluster analyses were inconsistent due to non-overlapping information between the phenotypic and molecular data. The correlation between the phenotypic and molecular diversity matrices was very low (0.001), which is in agreement with the inconsistencies observed between the clusters formed by the phenotypic and molecular diversity analyses. The joint phenotypic and genotypic diversity matrices grouped the inbred lines into three groups based on their reaction patterns to S. hermonthica, and this was able to exploit a broad estimate of the actual diversity among the inbred lines. The joint analysis shows an invaluable insight for measuring genetic diversity in the evaluated materials. The result indicates that wide genetic variability exists among the inbred lines and that the joint diversity analysis can be utilized to reliably assign the inbred lines into heterotic groups and also to enhance the level of resistance to Striga in new maize varieties.
- Published
- 2020
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22. Genetic diversity and population structure of a mini-core subset from the world cowpea (Vigna unguiculata (L.) Walp.) germplasm collection.
- Author
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Fatokun C, Girma G, Abberton M, Gedil M, Unachukwu N, Oyatomi O, Yusuf M, Rabbi I, and Boukar O
- Subjects
- Computational Biology methods, Databases, Genetic, Molecular Typing, Phylogeny, Seed Bank, Seeds, Vigna classification, Genetic Variation, Genetics, Population, Vigna genetics
- Abstract
The International Institute of Tropical Agriculture maintains the world's largest collection of cowpea germplasm of over 15,000 accessions. A sub-set of 298 lines from the loosely composed mini core collection of 370 landraces were genotyped based on genotyping by sequencing (GBS). Ward's minimum variance hierarchical cluster analysis, model-based ancestry analysis and discriminant analysis of principal component (DAPC) were carried out on this sub-set. Three clusters were identified by the different clustering methods. Principal component analysis further supported the three clusters especially when accessions are scattered along the axes of the first two principal components. The first two principal components explained a total of 22.30% of the variation. Cluster one comprises 115 accessions from the largest number of countries and has the highest gene diversity, heterozygosity and polymorphic information content (PIC) values. Cluster two is made up of 102 accessions, 90 percent of which are from West and Central Africa. Analysis of molecular variance shows that the most variation is among accessions and lowest among clusters. No cluster is made exclusively of accessions from a single country. Based on SNP markers, the sub set of cowpea mini core germplasm collection used in this study encompasses the diversity in the crop.
- Published
- 2018
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23. Genetic Gains in Grain Yield of a Maize Population Improved through Marker Assisted Recurrent Selection under Stress and Non-stress Conditions in West Africa.
- Author
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Abdulmalik RO, Menkir A, Meseka SK, Unachukwu N, Ado SG, Olarewaju JD, Aba DA, Hearne S, Crossa J, and Gedil M
- Abstract
Marker-assisted recurrent selection (MARS) is a breeding method used to accumulate favorable alleles that for example confer tolerance to drought in inbred lines from several genomic regions within a single population. A bi-parental cross formed from two parents that combine resistance to Striga hermonthica with drought tolerance, which was improved through MARS, was used to assess changes in the frequency of favorable alleles and its impact on inbred line improvement. A total of 200 testcrosses of randomly selected S
1 lines derived from the original (C0 ) and advanced selection cycles of this bi-parental population, were evaluated under drought stress (DS) and well-watered (WW) conditions at Ikenne and under artificial Striga infestation at Abuja and Mokwa in Nigeria in 2014 and 2015. Also, 60 randomly selected S1 lines each derived from the four cycles (C0 , C1 , C2 , C3 ) were genotyped with 233 SNP markers using KASP assay. The results showed that the frequency of favorable alleles increased with MARS in the bi-parental population with none of the markers showing fixation. The gain in grain yield was not significant under DS condition due to the combined effect of DS and armyworm infestation in 2015. Because the parents used for developing the bi-parental cross combined tolerance to drought with resistance to Striga , improvement in grain yield under DS did not result in undesirable changes in resistance to the parasite in the bi-parental maize population improved through MARS. MARS increased the mean number of combinations of favorable alleles in S1 lines from 114 in C0 to 124 in C3 . The level of heterozygosity decreased by 15%, while homozygosity increased by 13% due to the loss of some genotypes in the population. This study demonstrated the effectiveness of MARS in increasing the frequency of favorable alleles for tolerance to drought without disrupting the level of resistance to Striga in a bi-parental population targeted as a source of improved maize inbred lines.- Published
- 2017
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24. Genetic Gains in Yield and Yield Related Traits under Drought Stress and Favorable Environments in a Maize Population Improved Using Marker Assisted Recurrent Selection.
- Author
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Bankole F, Menkir A, Olaoye G, Crossa J, Hearne S, Unachukwu N, and Gedil M
- Abstract
The objective of marker assisted recurrent selection (MARS) is to increase the frequency of favorable marker alleles in a population before inbred line extraction. This approach was used to improve drought tolerance and grain yield (GY) in a biparental cross of two elite drought tolerant lines. The testcrosses of randomly selected 50 S
1 lines from each of the three selection cycles (C0 , C1 , C2 ) of the MARS population, parental testcrosses and the cross between the two parents (F1 ) were evaluated under drought stress (DS) and well watered (WW) well as under rainfed conditions to determine genetic gains in GY and other agronomic traits. Also, the S1 lines derived from each selection types were genotyped with single nucleotide polymorphism (SNP) markers. Testcrosses derived from C2 produced significantly higher grain field under DS than those derived from C0 with a relative genetic gain of 7% per cycle. Also, the testcrosses of S1 lines from C2 showed an average genetic gain of 1% per cycle under WW condition and 3% per cycle under rainfed condition. Molecular analysis revealed that the frequency of favorable marker alleles increased from 0.510 at C0 to 0.515 at C2 , while the effective number of alleles (Ne ) per locus decreased from C0 (1.93) to C2 (1.87). Our results underscore the effectiveness of MARS for improvement of GY under DS condition.- Published
- 2017
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