Chibundu N. Ezekiel

Prof. Chibundu N. Ezekiel

Department of Microbiology, Babcock University, Ilishan Remo, Ogun state, Nigeria
orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 August 2021 in Studies in Mycology
Verified
Journal Article
Open access
PCP.W. Crous
P.W. Crous
LLL. Lombard
L. Lombard
MSMarcelo Sandoval-Denis
Marcelo Sandoval-Denis
KSK.A. Seifert
K.A. Seifert
HSH.-J. Schroers
H.-J. Schroers
MTM. Thines
M. Thines
Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae. Thus, an alternate hypothesis, namely a very broad concept of the genus Fusarium was proposed. In doing so, however, a significant body of data that supports distinct genera in Nectriaceae based on morphology, biology, and phylogeny is disregarded. A DNA phylogeny based on 19 orthologous protein-coding genes was presented to support a very broad concept of Fusarium at the F1 node in Nectriaceae. Here, we demonstrate that re-analyses of this dataset show that all 19 genes support the F3 node that represents Fusarium sensu stricto as defined by F. sambucinum (sexual morph synonym Gibberella pulicaris). The backbone of the phylogeny is resolved by the concatenated alignment, but only six of the 19 genes fully support the F1 node, representing the broad circumscription of Fusarium. Furthermore, a re-analysis of the concatenated dataset revealed alternate topologies in different phylogenetic algorithms, highlighting the deep divergence and unresolved placement of various Nectriaceae lineages proposed as members of Fusarium. Species of Fusarium s. str. are characterised by Gibberella sexual morphs, asexual morphs with thin- or thick-walled macroconidia that have variously shaped apical and basal cells, and trichothecene mycotoxin production, which separates them from other fusarioid genera. Here we show that the Wollenweber concept of Fusarium presently accounts for 20 segregate genera with clear-cut synapomorphic traits, and that fusarioid macroconidia represent a character that has been gained or lost multiple times throughout Nectriaceae. Thus, the very broad circumscription of Fusarium is blurry and without apparent synapomorphies, and does not include all genera with fusarium-like macroconidia, which are spread throughout Nectriaceae (e.g., Cosmosporella, Macroconia, Microcera). In this study four new genera are introduced, along with 18 new species and 16 new combinations. These names convey information about relationships, morphology, and ecological preference that would otherwise be lost in a broader definition of Fusarium. To assist users to correctly identify fusarioid genera and species, we introduce a new online identification database, Fusarioid-ID, accessible at www.fusarium.org. The database comprises partial sequences from multiple genes commonly used to identify fusarioid taxa (act1, CaM, his3, rpb1, rpb2, tef1, tub2, ITS, and LSU). In this paper, we also present a nomenclator of names that have been introduced in Fusarium up to January 2021 as well as their current status, types, and diagnostic DNA barcode data. In this study, researchers from 46 countries, representing taxonomists, plant pathologists, medical mycologists, quarantine officials, regulatory agencies, and students, strongly support the application and use of a more precisely delimited Fusarium (= Gibberella) concept to accommodate taxa from the robust monophyletic node F3 on the basis of a well-defined and unique combination of morphological and biochemical features. This F3 node includes, among others, species of the F. fujikuroi, F. incarnatum-equiseti, F. oxysporum, and F. sambucinum species complexes, but not species of Bisifusarium [F. dimerum species complex (SC)], Cyanonectria (F. buxicola SC), Geejayessia (F. staphyleae SC), Neocosmospora (F. solani SC) or Rectifusarium (F. ventricosum SC). The present study represents the first step to generating a new online monograph of Fusarium and allied fusarioid genera (www.fusarium.org).

25 September 2017 in Critical Reviews in Food Science and Nutrition
Verified
Journal Article
Open access
JMJane Misihairabgwi
Jane Misihairabgwi
CEChibundu N. Ezekiel
Chibundu N. Ezekiel
MSMichael Sulyok
Michael Sulyok
GSG. S. Shephard
G. S. Shephard
RKR. Krska
R. Krska
Major staple foods in Southern Africa are prone to mycotoxin contamination, posing health risks to consumers and consequent economic losses. Regional climatic zones favor the growth of one or more main mycotoxin producing fungi, Aspergillus, Fusarium and Penicillium. Aflatoxin contamination is mainly reported in maize, peanuts and their products, fumonisin contamination in maize and maize products and patulin in apple juice. Lack of awareness of occurrence and risks of mycotoxins, poor agricultural practices and undiversified diets predispose populations to dietary mycotoxin exposure. Due to a scarcity of reports in Southern Africa, reviews on mycotoxin contamination of foods in Africa have mainly focused on Central, Eastern and Western Africa. However, over the last decade, a substantial number of reports of dietary mycotoxins in South Africa have been documented, with fewer reports documented in Botswana, Lesotho, Malawi, Mozambique, Zambia and Zimbabwe. Despite the reported high dietary levels of mycotoxins, legislation for their control is absent in most countries in the region. This review presents an up-to-date documentation of the epidemiology of mycotoxins in agricultural food commodities and discusses the implications on public health, current and recommended mitigation strategies, legislation, and challenges of mycotoxin research in Southern Africa.

1 May 2014 in Environment International
Verified
Journal Article
Closed access
CEChibundu N. Ezekiel
Chibundu N. Ezekiel
BWBenedikt Warth
Benedikt Warth
IOIsaac M. Ogara
Isaac M. Ogara
WAWilfred A. Abia
Wilfred A. Abia
VEVictoria C. Ezekiel
Victoria C. Ezekiel
RBRanajit Bandyopadhyay
Ranajit Bandyopadhyay

1 August 2018 in Analytica Chimica Acta
Verified
Journal Article
Open access
BSBojan Sarkanj
Bojan Sarkanj
CEChibundu N. Ezekiel
Chibundu N. Ezekiel
Paul C. TurnerPaul C. Turner
Paul C. Turner
Wilfred A. AbiaWilfred A. Abia
Wilfred A. Abia
MRMichael Rychlik
Michael Rychlik
BWBenedikt Warth
Benedikt Warth
There is a critical need to better understand the patterns, levels and combinatory effects of exposures we are facing through our diet and environment. Mycotoxin mixtures are of particular concern due to chronic low dose exposures caused by naturally contaminated food. To facilitate new insights into their role in chronic disease, mycotoxins and their metabolites are quantified in bio-fluids as biomarkers of exposure. Here, we describe a highly sensitive urinary assay based on ultra-high performance liquid chromatography - tandem mass spectrometer (UHPLC-MS/MS) and 13C-labelled or deuterated internal standards covering the most relevant regulated and emerging mycotoxins. Utilizing enzymatic pre-treatment, solid phase extraction and UHPLC separation, the sensitivity of the method was significantly higher (10-160x lower LODs) than in a previously described method used for comparison purpose, and stable isotopes provided compensation for challenging matrix effects. This method was in-house validated and applied to re-assess mycotoxin exposure in urine samples obtained from Nigerian children, adolescent and adults, naturally exposed through their regular diet. Owing to the methods high sensitivity, biomarkers were detected in all samples. The mycoestrogen zearalenone was the most frequently detected contaminant (82%) but also ochratoxin A (76%), aflatoxin M1 (73%) and fumonisin B1 (71%) were quantified in a large share of urines. Overall, 57% of 120 urines were contaminated with both, aflatoxin M1 and fumonisin B1, and other co-exposures were frequent. These results clearly demonstrate the advanced performance of the method to assess lowest background exposures (pg mL-1 range) using a single, highly robust assay that will allow for the systematic investigation of low dose effects on human health.

1 June 2017 in International Journal of Food Microbiology
Verified
Journal Article
Closed access
OOOluwawapelumi A. Oyedele
Oluwawapelumi A. Oyedele
CEChibundu N. Ezekiel
Chibundu N. Ezekiel
MSMichael Sulyok
Michael Sulyok
MAModupeade Christianah Adetunji
Modupeade Christianah Adetunji
BWBenedikt Warth
Benedikt Warth
RKRudolf Krska
Rudolf Krska

3 February 2020 in Comprehensive Reviews in Food Science and Food Safety
Verified
Journal Article
Open access
PDF file
OMOluwadamilola Mathew Makinde
Oluwadamilola Mathew Makinde
KAKolawole I. Ayeni
Kolawole I. Ayeni
MSMichael Sulyok
Michael Sulyok
RKRudolf Krska
Rudolf Krska
RARasheed Adeleke
Rasheed Adeleke
CEChibundu N. Ezekiel
Chibundu N. Ezekiel
Ready‐to‐eat foods (RTEs) are foods consumed without any further processing. They are widely consumed as choice meals especially by school‐aged children and the fast‐paced working class in most low‐ and middle‐income countries (LMICs), where they contribute substantially to the dietary intake. Depending on the type of processing and packaging material, RTEs could be industrially or traditionally processed. Typically, RTE vendors are of low literacy level, as such, they lack knowledge about good hygiene and food handling practices. In addition, RTEs are often vended in outdoor environments such that they are exposed to several contaminants of microbial origin. Depending on the quantity and type of food contaminant, consumption of contaminated RTEs may result in foodborne diseases and several other adverse health effects in humans. This could constitute major hurdles to growth and development in LMICs. Therefore, this review focuses on providing comprehensive and recent occurrence and impact data on the frequently encountered contaminants of microbial origin published in LMICs within the last decade (2009 to 2018). We have also suggested viable food safety solutions for preventing and controlling the food contamination and promoting consumer health.