Abstract Composite water and sediment samples were taken from Nkenye stream at five different sampling stations during wet and dry seasons. Water quality parameters were analyzed using standard methods to ascertain the effect of human activities on the water quality. The variations in the physicochemical and biological parameters were observed from station to station both in the dry and wet seasons. These variations were attributed to human activities. Results showed significant seasonal var...
Abstract The soda lakes of Kenya provide an extreme environment where diverse groups of microorganisms thrive. They are characterized by great variation in temperature, halophillic and alkaliphilic- extreme conditions. Lake Sonachi has been the study site for this research. The study sort to isolate, characterize and identify fungi, screen for potential exo-enzymes and secondary metabolites production that may be of industrial application. Malt extract agar was used in the isolation of fungi...
Abstract Dissipation of hexazinone in Zeolite X treated wastewater followed pseudo first-order kinetics giving a calculated half-life of 41 days compared to a half-life of 144 days in untreated wastewater. The herbicide degraded faster (0.0067 h-1) in treated than in nonzeolite- treated wastewater (0.0027 h-1) forming products A, B, C, D and E within the first 12 h. Zeolite X effectively catalyzed the formation of product A compared to the rest. Calculated rate constants for formation of pro...
Abstract Although pubescence has traditionally been considered to be related to the water economy of plants, the results are ambivalent and vary between different species. We tested two contrasting hypotheses for the functional significance of leaf pubescence of Proteaceae species from the Cape Floristic Region. First, we hypothesised that pubescence is a xeromorphic trait that conserves water by increasing the boundary layer resistance to diffusion. Water loss was measured in two morphotype...
Abstract In this study five aqueous extracts; Bidens pilosa, Strychnos henningsii, Aspilia pluriseta, Catha edulis and Erythrina abyssinica were screened for anti-diabetic activity and their in vivo safety evaluated. The anti-diabetic activity was assessed by intraperitoneally injecting varying doses of aqueous extracts of the five plants into alloxanised mice. Toxicity was determined by injecting normal mice with 450mg of the plant extract / kg body weight and observing the effects of the e...
Abstract Marine sediment, seawater and several species of seaplants along the Kenya- Mombasa coastal region were analyzed to determine the levels of heavy metals by AAS and EDXRF and organochlorine pesticides (OCPs) by GLC-ECD. In marine sediments, there were high levels of manganese (1100 mg/L) at Vanga, compared to other study sites. In seawater, the heavy metals were detected in levels higher than those considered as natural in the ocean and the range was 0.01–0.30 mg/L. OCPs were detec...
Abstract Metal pollution and its health effects present a challenge currently facing the developing countries. Metal poisoning is usually difficult and expensive to assess or screen in these countries due to limited resources, which means that policies, guidelines, regulations and institutional managements are limited. Hair and nail as biopsy materials were suggested as more attractive biomarkers in assessing heavy metals environmental exposure. This paper deals with quantitative determinati...
Abstract The methanolic extract of the fresh root bark and berries of Solanum aculeastrum showed significant activity against host snails of schistosomiasis. The berries extract was more potent with 100% snail kill at 50 ppm. Fractionation increased activity with 100% mortality at 20 ppm. The aqueous and methanolic extracts of the berries showed moderate antimicrobial activity, increasing by fractionation.
Abstract This study was to compare the total phenolic (TP) content in extracts from eleven plant materials collected at different geographical locations in Kenya, Nigeria, and USA. These plants have been selected because the majority of them are highly pigmented, from yellow to purple, and would therefore have economic value in industries for producing antioxidants and surfactants. Two of them were collected from the industrial and domestic waste outlets. Each analysis was achieved using the...
Abstract Sixty organic and aqueous extracts of eleven plants used for the control of malaria by local communities in Kisii District, Kenya were screened for in vitro anti-plasmodial activity. The plants selection was based on existing ethnobotanical information and interviews with local communities. The extracts were tested against chloroquine sensitive and resistant laboratory adapted strains of Plasmodium falciparum. The study revealed that 63.6% of the plants were active (IC50 ≤ 100 μg...
Abstract Syntrophobotulus glycolicus Friedrich et al. 1996 is currently the only member of the genus Syntrophobotulus within the family Peptococcaceae. The species is of interest because of its isolated phylogenetic location in the genome-sequenced fraction of tree of life. When grown in pure culture with glyoxylate as carbon source the organism utilizes glyoxylate through fermentative oxidation, whereas, when grown in syntrophic co-culture with homoacetogenic or methanogenic bacteria, it is...
Abstract Trebouxiophytes of the Dictyosphaerium–morphotype from inland waters of Africa were studied using a polyphasic approach of SSU and ITS rDNA phylogeny, secondary structure of the ITS and observations made with a light microscope. Although the morphological criteria for differentiating species and genera are scarce, the genetic diversity of these algae was very high. Based on our genetic analysis findings, we described four new genera containing five new species: Compactochlorella d...
Abstract The last two decades have witnessed increasing episodes of lesser flamingo die-offs in East Africa. Based on data on phytoplankton composition, biomass, and flamingo population density in three alkaline-saline lakes of Kenya (Bogoria, Nakuru, and Oloidien) in 2001–2010, this study explored the link between sudden flamingo deaths and fluctuations in algal food quantity and quality. The phytoplankton biomass ranged from 13 to 768 mg Æ L)1. Similarly, flamingo numbers varied widely ...
Abstract PCR-based denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene fragments was used to identify the cyanobacterial phylotypes in sediments and plankton of saline–alkaline and freshwater lakes of Kenya. The detection of the aminotransferase domain located on modules mcyE and ndaF using specific molecular markers confirmed the presence of potential toxin-producing cyanobacteria. The eight nucleotide sequences obtained from DGGE bands were placed in three divergent ...
Abstract Cyanobacterial mats at hot springs on the shore of the alkaline Lake Bogoria, Kenya, were investigated regarding species community and cyanobacterial toxin content. The hepatotoxins microcystin-LR, -RR, -LF and -YR, and the neurotoxin anatoxin-a were present. The mats were dominated by Phormidium terebriformis, Oscillatoria willei, Spirulina subsalsa and Synechococcus bigranulatus. The concentration of microcystins in mat samples, ranged from 221 to 845 microg microcystin-LR equival...