Bio

Personal Information

Present Appointment: Director and Senior Lecturer, Centre for Biotechnology and Bioinformatics,
University of Nairobi-KENYA

Highest Qualification Profile

1. Doctor of Philosophy in Biotechnology
2. Post Doctoral Research-Bioprocessing-Fermentation and optimization of bioproducts and processes using bioreactors
at the Bioprocess Research Unit-University of Cape town

Areas of specialization

Biotechnology, Industrial or applied Microbiology/Fermentation Technology

Research Interests

Publications


2021

Jekayinoluwa T, Tripathi JN, Dugdale B, Obiero G, E M, Dale J, L T.  2021.  Transgenic Expression of dsRNA Targeting the Pentalonia nigronervosa acetylcholinesterase Gene in Banana and Plantain Reduces Aphid Populations. Plants.. 10 (4)(613):1-18.

2020

Omwenga, I, Aboge GO, Mitema ES, Obiero G, Ngaywa C, Ngwili N, Wamwere G, Wainaina M, Bett B.  2020.  Antimicrobial Usage and Detection of Multidrug-Resistant , Including Methicillin-Resistant Strains in Raw Milk of Livestock from Northern Kenya., 2020 Nov 12. Microbial drug resistance (Larchmont, N.Y.). Abstract

The association of antimicrobial usage (AMU) with prevalence of antimicrobial-resistant (AMR) , including methicillin-resistant (MRSA) in livestock raw milk consumed by pastoralists in Kenya remains unclear. We investigated the relationship between AMU and emergence of multidrug-resistant (MDR) , including MRSA in raw milk of livestock. AMU data were obtained using sales records from veterinary pharmacies. was isolated from 603 milk samples from various livestock species, including sheep, goat, cow, and camel reared in Isiolo and Marsabit counties in Kenya. Resistant phenotypes and genotypes were determined by disc diffusion and molecular methods, respectively. Correlation between AMU and occurrence of resistance was determined by Pearson's correlation coefficient () method. The consumption of various antimicrobial classes were as follows; 4,168 kg of oxytetracycline, 70 kg of sulfonamides, 49.7 kg of aminoglycosides, 46 kg of beta-lactams, 39.4 kg of macrolides, and 0.52 kg for trimethoprim. The isolates were mainly resistant to tetracycline (79%), ampicillin (58%), and oxacillin (33%), respectively. A few isolates (5-18%) were resistant to clindamycin, cephalexin, erythromycin, kanamycin, and ciprofloxacin. Most of the MDR- isolates were MRSA (94%). The genetic determinants found in the AMR isolates included K/M (96.5%/19%) for tetracycline, (79%) for penicillin, (53%) for aminoglycosides, A (41%) for oxacillin, and A/A (24%/7%) for macrolides. Oxytetracycline usage was correlated to K/M ( = 0.62/1) detection, penicillins to A/ ( = 0.86/0.98), aminoglycoside to ( 0.76/-13), and macrolide usages for detection of A/A ( = 0.94/0.77). AMU appeared to be associated with occurrence of MDR-SA and the M detection. Consumption of raw milk contaminated with MRSA could pose a serious public health risk in pastoral communities in northern Kenya.

Jekayinoluwa, T, Tripathi JN, Obiero G, Muge E, Tripathi L.  2020.  Phytochemical Analysis and Establishment of Embryogenic Cell Suspension and -mediated Transformation for Farmer Preferred Cultivars of West African Plantain ( spp.)., 2020 Jun 24. Plants (Basel, Switzerland). 9(6) Abstract

Banana and plantain are among the foremost staple food crops providing food and livelihood to over 500 million people in tropical countries. Despite the importance, their production is hampered due to several biotic and abiotic stresses. Plant tissue culture techniques such as somatic embryogenesis and genetic transformation offer a valuable tool for genetic improvement. Identification and quantification of phytochemicals found in banana and plantain are essential in optimizing in vitro activities for crop improvement. Total antioxidants, phenolics, flavonoids, and tannins were quantified in various explants obtained from the field, as well as in vitro plants of banana and plantain cultivars. The result showed genotypic variation in the phytochemicals of selected cultivars. The embryogenic cell suspensions were developed for three farmer-preferred plantain cultivars, Agbagba, Obino l'Ewai, and Orishele, using different MS and B5-based culture media. Both culture media supported the development of friable embryogenic calli (FEC), while MS culture media supported the proliferation of fine cell suspension in liquid culture media. The percentage of FEC generated for Agbagba, Obino l'Ewai, and Orishele were 22 ± 24%, 13 ± 28%, and 9 ± 16%, respectively. Cell suspensions produced from FECs were successfully transformed by -mediated transformation with reporter gene constructs and regenerated into whole plants.

2019

Kinyanyi, Amwayi, Wamalwa, M;, Obiero, G.O.  2019.  Comparative in silico study of congocidine congeners as potential inhibitors of African swine fever virus. Plos One. 14(8)

2018

Kinyanyi, D, Obiero G, Amwayi P, Mwaniki S.  2018.  In silico structural and functional prediction of African swine fever virus protein-B263R reveals features of a TATA-binding protein. PeerJ Inc.. 6(3):e4396. Abstract

African swine fever virus (ASFV) is the etiological agent of ASF, a fatal hemorrhagic fever that affects domestic pigs. There is currently no vaccine against ASFV, making it a significant threat to the pork industry. The ASFV genome sequence has been published; however, about half of ASFV open reading frames have not been characterized in terms of their structure and function despite being essential for our understanding of ASFV pathogenicity. The present study reports the three-dimensional structure and function of uncharacterized protein, pB263R (NP_042780. 1), an open reading frame found in all ASFV strains. Sequence-based profiling and hidden Markov model search methods were used to identify remote pB263R homologs. Iterative Threading ASSEmbly Refinement (I-TASSER) was used to model the three-dimensional structure of pB263R. The posterior probability of fold family assignment was calculated using TM-fold, and biological function was assigned using TM-site, RaptorXBinding, Gene Ontology, and TM-align. Our results suggests that pB263R has the features of a TATA-binding protein and is thus likely to be involved in viral gene transcription.

2017

Mwafulirwa, GAS, Obiero G, Mpeketula P.  2017.  Isolation of indigenous glyphosate degrading microbes from selected agro ecological zones of Malawi. Research Journal of Recent Sciences. 6(12):1-8.
J.M.Mahasi, H.A.Ogot, Okoth SA, G.O.Obiero.  2017.  Assesment of Asian soybean rust (Phakopsora pachyrhizi) disease severity in selected districts of Western Kenya. International Journal of Agronomy and Agricultural Research. 11(2):50-53.
Jakubowski, H, Xie J, Mitra AK, Ghooi R, Hosseinkhani S, Alipour M, Hajipour B, Obiero G.  2017.  The Global Ethics Corner: foundations, beliefs, and the teaching of biomedical and scientific ethics around the world. Biochemistry and Molecular Biology Education. 45(5):385-395. Abstract

The profound advances in the biomolecular sciences over the last decades have enabled similar advances in biomedicine. These advances have increasingly challenged our abilities to deploy them in an equitable and ethically acceptable manner. As such, it has become necessary and important to teach biomedical and scientific ethics to our students who will become the researchers, medical professionals, and global citizens of the future. As advances in the biosciences and medicine are made, developed, and used across the globe, our survival on an endangered planet requires global dialog and consensual action. To that end, a group of us from around the world have come together to describe the differing foundations of our ethical beliefs, and how ethical issues in biomedicine and in science are described and confronted in our countries. We hope to show the commonality in our beliefs and practices.

2014

Smit, M, Obiero G, Andreas Shiningavamwe, Albertyn J, Jean-Marc.  2014.  Heterologous expression of the benzoate para-hydroxylase encoding gene (CYP53B1) from Rhodotorula minuta by Yarrowia lipolytica. Applied Microibiology and Biotechnology. 72(2):323-329.

2009

Wanjala W Cornelius, Teresa Akeng'a, George O Obiero, Lutta KP.  2009.  Antifeedant Activities of the Erythrinaline Alkaloids from Erythrina latissima against Spodoptera littoralis (Lepidoptera noctuidae). Records of Natural Products. 3(2):96. Abstract

The antifeedant activities of the Erythrina alkaloids from the seeds, seed pods and flowers of Erythrina latissima were investigated in laboratory dual-choice bioassays using third-instar Spodoptera littoralis (Boisduval) larvae. The new compound (+)-11β-methoxy-10-oxoerysotramidine (1) from the flowers, showed potent dose dependant activity at concentration 500≥ ppm while (+)-10, 11-dioxoerysotramidine (2) also new from the flowers showed potent dose dependant activity at concentration 100≥ ppm. Three known compounds (+)-erysotrine,(+)-erysotramidine,(+)-erythraline,(+)-11β-hydroxyerysotramidine showed potent dose dependant antifeedant activity at concentrations 100≥ ppm while (+)-10, 11-dioxoerysotrine and (+)-11βhydroxyerysotramidine also a known compounds showed potent dose dependant antifeedant activity at concentrations 300≥ ppm. Three known compounds (+)-11β-methoxyerysotramidine,(+)-8-oxoerythraline and (+)-15 (16) β-D-glucoerysodine showed no appreciable change in antifeedant activity with concentration change.

Wanjala W Cornelius, Akeng’a T, George O Obiero, Lutta KP.  2009.  Institute of Tropical Medicine and Infectious Diseases, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000-00200, Nairobi, KENYA.. Records of Natural Products. 3(2) Abstract

The antifeedant activities of the Erythrina alkaloids from the seeds, seed pods and flowers of Erythrina latissima were investigated in laboratory dual-choice bioassays using third-instar Spodoptera littoralis (Boisduval) larvae. The new compound (+)-11β-methoxy-10-oxoerysotramidine (1) from the flowers, showed potent dose dependant activity at concentration>= 500 pm while (+)-10, 11-dioxoerysotramidine (2) also new from the flowers showed potent dose dependant activity at concentration>= 100 ppm. Three known compounds (+)-erysotrine,(+)-erysotramidine,(+)-erythraline,(+)-11β-hydroxyerysotramidine showed potent dose dependant antifeedant activity at concentrations>= 100 ppm while (+)-10, 11-dioxoerysotrine and (+)-11 b-hydroxyerysotramidine also a known compounds showed potent dose dependant antifeedant activity at concentrations>= 100 ppm.

Mabetsela, N, Marx, S, G.O O.  2009.  Optimization of enzymatic conversion of maize stover to bioethanol. South African Chemica l Engineering Congress. :BookofAbstracts,141., Sommerset West, South Africa
Nquma, TY, Sanette Marx, Obiero G.  2009.  Optimisation of ethanol yield from cassava, 20th-23rd Sept. South African Chemical Engineering Congress. :BookofAbstracts,128., Sommerset west, South Africa
Wanjala W Cornelius, Teresa Akeng'a, George O Obiero, Lutta. KP.  2009.  ). Antifeedant activities of Erythrinaline alkaloids from Erythrina latissima against Sporodoptera littoralis (Lepidoptera noctuidae).. Records of Natural Products. 3(2):96-103.

2008

Cris Theron, Khajamohiddin Syed, Andreas Shiningavamwe, Evodia Setati, Obiero G, Newlande van Rooyen, Limpho Ramarobi, Simbarashe Mabwe, Jacobus Albetyn,. J-M.  2008.  Yarrowia Lipolytica as a host for heterologous expression of cytochrome P450 monoxygenase. Biotrans 2007 conference . , Oviedo, Spain
Obiero, G, Martha Smit,. SHTL.  2008.  Bioconversion of linear alkanes to dicarboxylic acids using genetically engineered yeast strains, 2008. Bio-08 conference.
Cris Theron, Khajamohiddin Syed, Andreas Shiningavamwe, Evodia Setati, Obiero G, Newlande van Rooyen, Limpho Ramarobi, Simbarashe Mabwe, Jacobus Albetyn, Jean-Marc Nicaud,. MS.  2008.  Yarrowia Lipolytica as a host for heterologous expression of cytochrome P450 monoxygenase. Bio-08 conference . , Grahamstown, South Africa

2007

Harrison, L.J.S, Obiero, G.O, Gumede, SP, Highes, A, McMahon, A.R, Rawatlal, R, MS S.  2007.  Activation of Linear Alkanes to Oxygenated Intermediates and Products using Genetically Engineered Yeast streams. Catalysis Conference of South Africa (CATSA). , Richards Bay, South Africa

2006

Obiero, GO.  2006.  Evaluation of Yarrowia lipolytica as a host for cytochrome P450 monooxygenase expression. University of the Free State. Abstract

Biohydroxylation reactions are catalyzed by various types of hydroxylating enzymes (Ayala and Torres, 2004) which include dioxygenases, lipooxygenases as well as CYP450 monooxygenases. These particular hydroxylation reactions have several advantages over chemical synthesis. Several microorganisms including yeasts have the ability to hydroxylate various substrates. The exploitation of microbial hydroxylations for the production of industrially useful products such as pharmaceuticals is a more recent development (Holland et al., 2000). Yeasts from the genera Schizosaccharomyces, Pichia, Saccharomyces and Yarrowia have all been used to express foreign CYP450 genes (Mukarami et al., 1990; Nthangeni et al., 2004) since they offer an advantage especially when a eukaryotic environment is required for the functional expression of the heterologous gene (Blanquet et al., 2003). A recent evaluation of several yeasts revealed that Y. lipolytica is, a highly attractive alternative host for secretion and expression cloning (Muller et al., 1998; Juretzek et al., 2001). However, a literature search on successful expression of CYP450s in Y. lipolytica yielded only six cases. Three of these were done in our laboratory. In most of the reported cases, the recombinant CYP450 activities were never evaluated in terms of whole cell biotransformations. It was therefore the aim of this study to evaluate Y. lipolytica as a recombinant whole-cell biocatalyst for hydroxylation reactions by using available Y. lipolytica strains overexpressing different CYP450s which were (i) CYP1A1 coding for polyaromatic hydrocarbon hydroxylase (ii) CYP53B1 coding for benzoate.

Obiero, G.O, MS S.  2006.  Biotransformation of phenylnonane using Yarrowia lipolytica overexpressing a benzoate para-hydroxylase from R. minuta., 4th-(th April, 2. 14th Congress of the South African Microbiology Society. , Pretoria, South Africa
Shiningavamwe, AN, Obiero, G.O, Albetyn, K, Nicaud J-M, Smit MS.  2006.  Heterologous expression of the benzoate para-hydroxylase encoding gene (CYP53B1) from Rhodotorula minuta by Yarrowia lipolytic. Journal of Applied Biotechnology and Biotechnology. 72:323-329.

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