James Nyirenda

University of Zambia | UNZA · Department of Chemistry

Water contamination by heavy metals and organic waste presents a great challenge in developing countries, thereby hampering access to safe water. In this work, activated carbons were prepared from Zea mays cob (MC), Anacardium occidentale (cashew nut shells-CNS), sawdust from Pinus oocarpa (SPO) and Pterocarpus angolensis (SPA) biomass waste found...

We report synthesis and characterization of an activated carbon-supported silver-silica nanocomposite (AC-Ag-SiO2) for removal of Cu²⁺, Pb²⁺, Cd²⁺ and Zn²⁺ ions from single and multi-metal aqueous solutions. Characterization experiments included Atomic force microscopy (AFM), Ultraviolet–visible spectrophotometry (UV–Vis), Fourier transform Infrare...

Cashew nutshell liquid (CNSL) is a cheap source of natural phenolic compounds that have numerous applications. These phenolic compounds have chemical structures with chromophores similar to those found in synthetic chemical UV-filters, which are present in commercial sunscreen products (SSPs). Thus, this study investigated the impact of solvents on...

Ethnopharmacological relevance Anemia is a very serious condition in Zambia. One of the plants that has been used traditionally is Phyllanthus muellerianus where different parts of shrub are used to treat a number of diseases in Zambian folklore medicine. Earlier studies have investigated medicinal properties of its aqueous root extracts. This stud...

In this paper, we report extraction of cashew nut shell liquid (CNSL) from cashew nut shell waste (CNSW) and further use of residues for generation of activated carbon for removal of heavy metals and methylene blue (MB). Solvent extraction yielded 24.6 ± 0.4%, 38.2 ± 0.4% and 40.1 ± 0.9% for petroleum ether, hexane and ethanol respectively. Phytoch...

In this paper, we report on the development and optimization of a copper anode material coated with a thin polyaniline layer for use in a microbial fuel cell. The polyaniline materials were optimized in terms of their conductivity. The synthesis was carried out using hydrochloric acid, sulfuric acid, and formic acid as dopants. The materials were c...

Biodegradation is the breakdown of complex organic compounds into simpler molecules like carbon dioxide and water by microorganisms like bacteria and fungi. Biodegradation studies of pharmaceuticals are initially done to assess which pharmaceuticals are persistent in the environment. Whole pharmaceuticals or their metabolites are excreted from the...

Recently, there has been an increased interest in bridging the knowledge gap in the occurrence and fate of pharmaceuticals in African urban water cycles. In this study, the occurrence of 7 antibiotics and 3 antiretrovirals in source-separated urine, groundwater, wastewater and surface water of the peri-urban area of Chunga in Lusaka, Zambia, was st...

Recently, there has been an increased interest in bridging the knowledge gap in the occurrence and fate of pharmaceuticals in African urban water cycles. In this study, the occurrence of 7 antibiotics and 3 antiretrovirals in source-separated urine, groundwater, wastewater and surface water of the peri-urban area of Chunga in Lusaka, Zambia, was st...

Lannea edulis (Sond.) Engl. commonly known as wild grape is used traditionally for the treatment of diabetes. It is only found in Eastern and Southern Africa. Phytochemical screening, antihyperglycemic and antihyperlipidemic effects of aqueous extracts of L. edulis in alloxan induced diabetic rats were carried out. We report herein the findings of...

Lannea edulis (Sond.) Engl. commonly known as wild grape is used traditionally for the treatment of diabetes. It is only found in Eastern and Southern Africa. Phytochemical screening, antihyperglycemic and antihyperlipidemic effects of aqueous extracts of L. edulis in alloxan induced diabetic rats were carried out. We report herein the findings of...

Background: The root of Steganotaenia araliacea is used for assisting labour in folk medicine. Recent reports indicate that the root could possess uterotonic substances. Objectives: The study aimed to evaluate three methods for the extraction of uterotonic principles from the root of S. araliacea growing in Zambia. Methods: Roots of the plant wer...

Even though some studies have shown that copper (Cu), copper oxide (CuO) and zinc oxide (ZnO) nanoparticles (NPs) are toxic to a number of organisms, fewer studies have investigated toxicity of these NPs in actual soils. This study investigated the effect of Cu, CuO and ZnO NPs in both urban and artificial soils. The aim was to examine the differen...

Some heavy metals (HMs) are of biological importance in animal life while others are important trace elements for plant growth and in higher animals. Despite various uses, their biotoxic effects arise once accumulation levels in animal bodies go beyond maximum permissible limits. Heavy Metal contamination is an environmental problem worldwide. This...

Asparagine-linked glycosylation of proteins is widespread not only in eukaryotes but also in archaea and some eubacteria. The oligosaccharyl transfer reaction is catalyzed by a membrane-bound enzyme, oligosaccharyltransferase (OST). The donor substrate is the lipid-linked oligosaccharide (LLO), and the acceptor is the asparagine residues in the N-g...

The genome of the hyperthermophilic archaeon, Archaeoglobus fulgidus, contains three paralogous AglB genes that encode oligosaccharyltransferase (OST) proteins. The OST enzymes catalyze the transfer of an oligosaccharide chain from lipid-linked oligosaccharides (LLO) to asparagine residues in proteins. The detergent-solubilized membrane fractions p...

Significance Asparagine-linked glycosylation is one of the most ubiquitous posttranslational protein modifications in all kingdoms of life. A membrane enzyme, oligosaccharyltransferase (OST), catalyzes the transfer of sugar chains onto the asparagine residues of the Asn-X-Ser/Thr sequon in acceptor proteins. We determined the structures of an archa...

Oligosaccharyltransferase (OST) is a membrane-bound enzyme that catalyzes the transfer of an oligosaccharide to an asparagine residue in glycoproteins. It possesses a binding pocket that recognizes Ser and Thr residues at the +2 position in the N-glycosylation consensus, Asn-X-Ser/Thr. We determined the crystal structures of the C-terminal globular...

Protein N-glycosylation occurs in the three domains of life. Oligosaccharyltransferase (OST) transfers glycan to asparagine in the N-glycosylation sequon. The catalytic subunit of OST is called STT3 in eukaryotes, AglB in archaea, and PglB in eubacteria. The genome of a hyperthermophilic archaeon, Archaeoglobus fulgidus, encodes three AglB paralogs...

Oligosaccharyltransferase (OST) catalyzes the transfer of an oligosaccharide from a lipid donor to an asparagine residue in nascent polypeptide chains. In the bacterium Campylobacter jejuni, a single-subunit membrane protein, PglB, catalyzes N-glycosylation. We report the 2.8 A resolution crystal structure of the C-terminal globular domain of PglB...