School of Health Science and Technology
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Item Antimutagenic effect of Kenyan Tea cultivars in a bacterial test system(2014) Mbuthia, Karori; Wachira, Francis; Ngure, Raphael; Mireji, Paul O; Wachira, SabinaThe antimutagenic effects of the aqueous tea extracts from Kenyan black, green and purple cultivars were evaluated by the Ames te st using Salmonella typhimurium tester strains TA 1538. Results obtained showed that tea had no toxicity or mutagenic activity at a concentration of 20% (w/v) unlike the mut agen sodium azide. However, using the formulae, percentage inhibition = [1 - T/M] ×10 0 where T is number of revertants per plate in presence of mutagen and test sample and M is number of revertants per plate in positive control, tea extracts had a significant (P<0.05) antimutagenic activity where the percent inhibition was 65% for green te a, 38% for purple tea and 19.17% for black tea. This was attributed to the radical scavenging activity of polyphenols. There is need therefore to carry out further research to help understand the precise mechanism of action especially for black and purple teas, and to explore other beneficial effects that these polyphenols may have, before they can be adopted for therapeutic use.Item Aquaporins Are Critical for Provision of Water during Lactation and Intrauterine Progeny Hydration to Maintain Tsetse Fly Reproductive Success(2014) Benoit, Joshua B; Hansen, Immo A; Attardo, Geoffrey M; Michalková, Veronika; Mireji, Paul O; Bargul, Joel L; Drake, Lisa L; Masiga, Daniel K; Aksoy, SerapTsetse flies undergo drastic fluctuations in their water content throughout their adult life history due to events such as blood feeding, dehydration and lactation, an essential feature of the viviparous reproductive biology of tsetse. Aquaporins (AQPs) are transmembrane proteins that allow water and other solutes to permeate through cellular membranes. Here we identify tsetse aquaporin (AQP) genes, examine their expression patterns under different physiological conditions (blood feeding, lactation and stress response) and perform functional analysis of three specific genes utilizing RNA interference (RNAi) gene silencing. Ten putative aquaporins were identified in the Glossina morsitans morsitans (Gmm) genome, two more than has been previously documented in any other insect. All organs, tissues, and body parts examined had distinct AQP expression patterns. Two AQP genes, gmmdripa and gmmdripb ( = gmmaqp1a and gmmaqp1b) are highly expressed in the milk gland/fat body tissues. The whole-body transcript levels of these two genes vary over the course of pregnancy. A set of three AQPs (gmmaqp5, gmmaqp2a, and gmmaqp4b) are expressed highly in the Malpighian tubules. Knockdown of gmmdripa and gmmdripb reduced the efficiency of water loss following a blood meal, increased dehydration tolerance and reduced heat tolerance of adult females. Knockdown of gmmdripa extended pregnancy length, and gmmdripb knockdown resulted in extended pregnancy duration and reduced progeny production. We found that knockdown of AQPs increased tsetse milk osmolality and reduced the water content in developing larva. Combined knockdown of gmmdripa, gmmdripb and gmmaqp5 extended pregnancy by 4–6 d, reduced pupal production by nearly 50%, increased milk osmolality by 20–25% and led to dehydration of feeding larvae. Based on these results, we conclude that gmmDripA and gmmDripB are critical for diuresis, stress tolerance and intrauterine lactation through the regulation of water and/or other uncharged solutes.Item Biological cost of tolerance to heavy metals in the mosquito Anopheles gambiae(2010) Mireji, PO; Keating, J; Hassanal, A; Mbogo, CM; Muturi, MN; Githure, JI; Beier, JCThe global rate of heavy metal pollution is rapidly increasing in various habitats. Anopheles malaria vector species (Diptera: Culicidae) appear to tolerate many aquatic habitats with metal pollutants, despite their normal proclivity for ‘clean’ water (i.e. low levels of organic matter). Investigations were conducted to establish whether there are biological costs for tolerance to heavy metals in Anopheles gambiae Giles sensu stricto and to assess the potential impact of heavy metal pollution on mosquito ecology. Anopheles gambiae s.s. were selected for cadmium, copper or lead tolerance through chronic exposure of immature stages to solutions of the metals for three successive generations. Biological costs were assessed in the fourth generation by horizontal life table analysis. Tolerance in larvae to cadmium (as cadmium chloride, CdCl2), copper [as copper II nitrate hydrate, Cu(NO3)2 2.5 H2O] and lead [as lead II nitrate, Pb(NO3)2], monitored by changes in LC50 concentrations of the metals, changed from 6.07 µg/L, 12.42 µg/L and 493.32 µg/L to 4.45 µg/L, 25.02 µg/L and 516.69 µg/L, respectively, after three generations of exposure. The metal-selected strains had a significantly lower magnitude of egg viability, larval and pupal survivorship, adult emergence, fecundity and net reproductive rate than the control strain. The population doubling times were significantly longer and the instantaneous birth rates lower in most metal-selected strains relative to the control strain. Our results suggest that although An. gambiae s.s. displays the potential to develop tolerance to heavy metals, particularly copper, this may occur at a significant biological cost, which can adversely affect its ecological fitness.Item Blood Meal Analysis and Virus Detection in Blood-Fed Mosquitoes Collected During the 2006–2007 Rift Valley Fever Outbreak in Kenya(2014) Lutomiah, Joel; Omond, David; Masiga, Daniel; Mutai, Collins; Mireji, Paul O; Ongus, Juliette; Linthicum, Ken J; Sang, RosemaryBackground: Rift Valley fever (RVF) is a zoonosis of domestic ruminants in Africa. Blood-fed mosquitoes collected during the 2006–2007 RVF outbreak in Kenya were analyzed to determine the virus infection status and animal source of the blood meals. Materials and Methods: Blood meals from individual mosquito abdomens were screened for viruses using Vero cells and RT-PCR. DNA was also extracted and the cytochrome c oxidase 1 (CO1) and cytochrome b (cytb) genes amplified by PCR. Purified amplicons were sequenced and queried in GenBank and Barcode of Life Database (BOLD) to identify the putative blood meal sources. Results: The predominant species in Garissa were Aedes ochraceus, (n=561, 76%) and Ae. mcintoshi, (n=176, 24%), and Mansonia uniformis, (n=24, 72.7%) in Baringo. Ae. ochraceus fed on goats (37.6%), cattle (16.4%), donkeys (10.7%), sheep (5.9%), and humans (5.3%). Ae. mcintoshi fed on the same animals in almost equal proportions. RVFV was isolated from Ae. ochraceus that had fed on sheep (4), goats (3), human (1), cattle (1), and unidentified host (1), with infection and dissemination rates of 1.8% (10/561) and 50% (5/10), respectively, and 0.56% (1/176) and 100% (1/1) in Ae. mcintoshi. In Baringo, Ma. uniformis fed on sheep (38%), frogs (13%), duikers (8%), cattle (4%), goats (4%), and unidentified hosts (29%), with infection and dissemination rates of 25% (6/24) and 83.3% (5/6), respectively. Ndumu virus (NDUV) was also isolated from Ae. ochraceus with infection and dissemination rates of 2.3% (13/561) and 76.9% (10/13), and Ae. mcintoshi, 2.8% (5/176) and 80% (4/5), respectively. Ten of the infected Ae. ochraceus had fed on goats, sheep (1), and unidentified hosts (2), and Ae. mcintoshi on goats (3), camel (1), and donkey (1). Conclusion: This study has demonstrated that RVFV and NDUV were concurrently circulating during the outbreak, and sheep and goats were the main amplifiers of these viruses respectively.Item Can we exploit and adapt indigenous knowledge and ethno-botanicals for a healthy living in the face of emerging diseases like Ebola in Africa(American Journal of Clinical and Experimental Medicine, 2015-02-14) Suki, K. K. MwendwaIn this essay, we attempted to catalogue and describe African indigenous knowledge, in contributing to sustainable health development in Sub Saharan Africa. In the face of poverty and threats of diseases such as ebola.We also describe how biotechnology can enhance cultural mechanism for improved health care. A snap shot of certain cultural habits that promote disease dissemination that would have to be modified is described. This report is basically a descriptive essay and partly based on a survey and collection of indigenous practices in Cameroon, and some cultures across countries in SSA. Some of the traditional knowledge relevant to disease transmission and control may form basis for experimentation, validation, development and application of appropriate medical biotechnologies for cheap, low tech disease control strategies and healthy living through a number of ethnobotanicals medicines, such as Occimum basilicum popularly called holy basil and in Kom language known as afuaih toh by many ethnicities of the Tikar in Ghana, Uganda, Gabon, parts of Kenya and Tanzania, Equitorial Guinea, Ethiopia, and Madagascar, who believe that the aromatic smell it emits dispels not only evil spirits but certain diseases such as HIV, Ebola and disease vectors. Such indigenous knowledge and science, with simple skills and familiarity, applied as an innovative approach to hygiene, medical challenges and disease control. Understand the practices, and see how to introduce interventions (incremental interventions), with existing indigenous knowledge enhanced with present science and technology, which you see can be applied to resolving present and possible outbreaks like Ebola. Generally called Macepo, tribes in Bukuru in northern Nigeria often used it to preserve dead bodies in remote villages where neither hospital nor morgue exist for days pending burial. Could scientific attention validate the use of African indigenous knowledge in Ebola prevention or future emerging diseases so that Africans can carry out safe burials within the context of their culture without risk of disease spread? We noted the believe amongst most ethnic groups regarding the use of Occimum basilicum, and leaf powder of some indigenous plants as a preservative for corpse or crops and insect repellent.This could serve as excellent platforms for mitigation and control of outbreaks such as Ebola.Item Changes in genotypes of Plasmodium falciparum human malaria parasite following withdrawal of chloroquine in Tiwi, Kenya(Elsevier, 2012) Mang’era, Clarence M.; Mbai, Fiona N; Omedo, Irene A; Mireji, Paul O; Omar, Sabah AChloroquine (CQ) drug was withdrawn in 1998 as a first-line treatment of uncomplicated malaria in Kenya. This was in response to resistance to the drug in Plasmodium falciparum malaria parasite. Investigations were conducted to determine prevalence of CQ resistance genotypes in the parasites in Tiwi, a malaria endemic town in Kenya, before and about a decade after the withdrawal of the drug. Blood samples were collected and spotted on filter papers in 1999 and 2008 from 75 and 77 out-patients respectively with uncomplicated malaria. The sampling was conducted using finger pricking technique. DNA was extracted from individual spots in the papers and screened for the presence of P. falciparum chloroquine resistance transporter (Pfcrt) and multi drug resistance (Pfmdr-1) markers using nested PCR. Nature of mutations (haplotypes) in the Pfcrt and Pfmdr-1 markers in the samples were confirmed using dot blot hybridization technique. Changes in pattern of CQ resistance in the parasite samples in 1999 and 2008 were assessed by Chi Square test. There was a significant (P < 0.05) reduction in CQ resistant genotypes of the parasite between 1999 and 2008. Pfmdr and Pfcrt CQ resistant genotypes in 2008 reduced to 54.10 and 63.64% respectively, from 75.39 and 88.0% respectively in 1999. This reduction was accompanied by emergence of Pfcrt specific CQ sensitive (IEK) and intermediate/partially CQ resistant (MET) haplotypes. Results suggest significant reversal of the phenotype of the parasite from chloroquine resistant to wild/sensitive type. The novel haplotypes indicates transitional phase of the parasite to the wild type. Current prevalence of chloroquine resistant genotype is definitely above the threshold for efficacious re-introduction of chloroquine for treatment of malaria in Tiwi.Item Chemosensory receptors in tsetse flies provide link between chemical and behavioural ecology(2014) Masiga, Daniel; Obiero, George; Macharia, Rosaline; Mireji, Paul O; Christoffels, AlanTsetse flies survive in a variety of environments across tropical Africa, often rising to large numbers, despite their low birth rate of one offspring every seven to nine days. They use olfactory receptors to process chemical signals in their environments to find food, escape from predators, and locate suitable larviposition sites. We discuss the identification of odorant and gustatory receptors in Glossina morsitans morsitans and the role genomics could play in management of nuisance insectsItem Coenzyme Q10 prevented full blown splenomegaly and decreased melarsoprol-induced reactive encephalopathy in mice infected with Trypanosoma brucei rhodesiense(2014) Nyariki, James Nyabuga; Thuita, John Kibuthu; Nyambati, Grace Kemunto; Isaac, Alfred OrinaObjective: To establish the modulatory effects of coenzyme Q10 on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalopathy (PTRE). Methods: Female Swiss white mice were orally administered with 200 mg/kg of coenzyme Q10 after which they were intraperitoneally inoculated with Trypanasoma brucei rhodesiense (T. b. rhodesiense). The resultant infection was allowed to develop and simulate all phases of human African trypanosomiasis and PTRE. Parasitaemia development, packed cell volume, haematological and pathological changes were determined. Results: A histological study in the brain tissue of T. b. rhodesiense infected mice demonstrated neuroinflammatory pathology which was highly amplified in the PTRE-induced groups. A prominent reduction in the severity of the neuroinflammatory response was detected when coenzyme-Q10 was administered. Furthermore, the mean tissue weight of spleen to body ratio in coenzyme Q10 supplemented group was significantly (P<0.05) different compared to unsupplemented groups, and clearly indicated that coenzyme Q10 prevented full blown splenomegaly pathogenesis by T. b. rhodesiense. A significant (P<0.05) increase in hemoglobin levels and red blood cells was observed in coenzyme Q10 mice compared to those infected and un-supplemented with coenzyme Q10. Conclusions: The capacity of coenzyme Q10 to alter the pathogenesis of T. b. rhodesiense infection in mice and following treatment with melarsoprol, may find application by rendering humans and animals less susceptible to deleterious effects of trypanosome infection such as splenomegaly and melarsoprol-induced PTRE and neurotoxicity.Item Deciphering the reproductive protein-protein interaction network in Anopheles gambiae with Drosophila melanogaster as a framework(2011) Achinko, Daniel; Mireji, Paul O; Catteruccia, Flaminia; Masiga, DanProtein-protein interactions (PPIs) are the most fundamental biological processes at the molecular level. The experimental methods for testing PPIs are time-consuming and are limited by analogs for many reactions. As a result, a computational model is necessary to predict PPIs and to explore the consequences of signal alterations in biological pathways. Reproductive control of the vector Anopheles gambiae using transgenic techniques poses a serious challenge. To meet this challenge, it would help to define the biological network involving the male accessory gland (MAG) proteins responsible for successful formation of the mating plug [1]. This plug forms in the male and is transferred to the female during mating, hence initiating the PPIs in both sexes. As is the case in Drosophila melanogaster, a close relative of A. gambiae, some MAG proteins responsible for the formation of the mating plug have been shown to alter the post-mating behavior of females.Item Differential induction of proteins in Anopheles gambiae sensu stricto (Diptera: Culicidae) larvae in response to heavy metal selection(2006) Mireji, Paul O; Keating, Joseph; Kenya, Eucharia; Mbogo, Charles; Nyambaka, Hudson; Osir, Ellie; Githure, John; Beier, JohnInvestigations were conducted to establish the magnitude and pattern of differential expression of proteins due to generational selection of third instar Anopheles gambiae s.s. Giles larvae by cadmium, copper and lead heavy metals, the three possible common urban pollutants. A susceptible strain of A. gambiae s.s. third instar larvae was separately placed under selection pressure with cadmium, copper and lead at LC30 and controls through five generations. First, third and fifth generation selection survivors were screened for differentially expressed proteins relative to non-exposed control by two-dimensional gel electrophoresis. Distribution patterns of the spots were analyzed by χ2 or Fishers' exact test and variations in expressions between and within generations by ANOVA. Most differentially expressed spots were acidic and of low molecular weight among all metals and generations. Type of heavy metal and generation were the main indicators of variations in differential expressions. Variation between generations was most significant among cadmium-selected populations of which the most number of spots were induced in the fifth generation. Most spots were induced in the copper-selected population in the third generation. The induced protein spots may be the products from respective genes that respond to heavy metals and counter their toxicity, thus building A. gambiae s.s. tolerance to these pollutants. The differential pattern and magnitude of expressed spots have potential application as molecular markers for assessment of anopheline adaptation status to heavy metals, and provide insight into the extent of environmental pollutionItem Effects of Dietary Decosahexaenoic Acid (DHA) on eNOS in Human Coronary Artery Endothelial Cells(2008) Stebbins, Charles L; Stice, James P; Hart, Michael; Mbai, Fiona N; Knowlton, Anne AEndothelial dysfunction occurs in heart disease and may reduce functional capacity via attenuations in peripheral blood flow. Dietary decosahexaenoic acid (DHA) may improve this dysfunction, but the mechanism is unknown. This study determined if DHA enhances expression and activity of eNOS in cultured human coronary artery endothelial cells (HCAEC). HCAEC from 4 donors were treated with 5 nM, 50 nM, or 1 μM DHA for 7 days to model chronic DHA exposure. A trend for increased expression of endothelial nitric oxide synthase (eNOS) and phospho-eNOS was observed with 5 and 50 nM DHA. DHA also enhanced expression of 2 proteins instrumental in activation of eNOS: phospho-Akt (5 and 50 nM) and HSP90 (50 nM and 1 μM). Vascular endothelial growth factor–induced activation of Akt increased NOx in treated (50 nM DHA) versus untreated HCAEC (9.2 ± 1.0 vs 3.3 ± 1.1 μmol/μg protein/μL). Findings suggest that DHA enhances eNOS and Akt activity, augments HSP90 expression, and increases NO bioavailability in response to Akt kinase activationItem Evaluation of the Anticonvulsant Activity of the Leaf Methanol Extract of Crassula arborescens (Mill.) Willd. (Crassulaceae) in Mice(2014) Amabeoku, George Jimboyeka; Mbamalu, Oluchi Nneka; Davids, Tasneem; Fakude, Samukelisiwe; Gqwaka, Anda; Mbai, Fiona N; Pieterse, Reighman; Shaik, AneesaCrassula arborescens (Mill.) Willd. subsp. Arborescens is widely used for the treatment of various ailments including diarrhoea, corns, epilepsy and as a purgati ve. However, no information exists in any literature to verify the acclaimed effecti veness of C. arborescens in the treatment of the various ailments. The study, therefore, intended to investigate the anticonvulsant activity of the leaf methanol extract of C. arborescens in mice. Acute toxicity study and phytochemical qualitative analysis of the plant extracts were also carried out. Chemically-induc ed convulsion methods were used to assess the anticonvulsant activity of C. arborescens . Standard methods were used for the acute t oxicity study and phytochemical analysis of the chemical compone nts of the plant extr act. PTZ (pentylenetetrazole), bicuculline, picrotoxin, NMDLA (N-methy l-DL-aspartic acid) or strychnine produced tonic convulsions i n all the mice used. Leaf methanol extract of Crassula arborescens , muscimol, phenobarbitone or di azepam significantly antagonised PTZ, bicuculline or picr otoxin-induced convulsion. C. arborescens or LY233053 significantly antagonised NMDLA-induced tonic convulsion. C. arborescens or phenobarbitone signifi cantly antagonised strychni ne-elicited tonic convulsi on. Phenytoin or DMSO (dimethylsulfoxide) did not significantly affect the tonic convulsion produced by PTZ, bicuculline, picrotoxin, NMDLA or strychnine. The LD 50 value obtained from intraperitoneal administration of C. arborescens was 781.6 mg/kg while that following oral administration of the plant extract was over 4,000 mg/kg. The phytochemical qualitativ e analysis done showed the presence of flavonoids, tannins, reducing sugar, saponins and triterpene steroids. The data obta ined in the study show that the leaf methan ol extract of Crassula arborescens has anticonvulsant activity which may be underpinned by GABAergic, glutaminergic and glycinergic mechanisms. The high LD 50 value obtained following the oral administra tion of the plant extract shows that the leaf methanol extract is non-toxic to animals.Item Expression of metallothionein and [alpha]-tubulin in heavy metal-tolerant(2010) Mireji, PO; Keating, J; Hassanali, A; Impoinvil, DE; Mbogo, CM; Muturi, MN; Nyambaka, H; Kenya, EU; Githure, JI; Beier, JCItem Expression of metallothionein and α-tubulin in heavy metal-tolerant Anopheles gambiae sensu stricto (Diptera: Culicidae)(2010) Mireji, Paul O; Keating, Joseph; Hassanali, Ahmed; Impoinvil, Daniel E; Mbogo, Charles M; Muturi, Martha N; Nyambaka, Hudson; Kenya, Eucharia U; Githure, John I; Beier, John CAnopheles mosquitoes have been shown to adapt to heavy metals in their natural habitats. In this study we explored the possibility of using Anopheles gambiae sensu stricto as bio-reporters for environmental heavy metal pollution through expressions of their metal-responsive metallothionein and α-tubulin genes. The study was undertaken with third instar larvae after selection by cadmium, copper, or lead at LC30 through five successive generations. Expression levels were determined in the 5th generation by semi-quantitative RT-PCR on the experimental and control populations. The data were analyzed using one-way ANOVA. The highest metallothionein (F3, 11=4.574, P=0.038) and α-tubulin (F3, 11=12.961, P=0.002) responses were observed in cadmium-tolerant treatments. There was significantly higher expression of metallothionein in cadmium or copper treatments relative to the control (P=0.012), and in cadmium than in lead treatments (P=0.044). Expressions of α-tubulin were significantly higher in cadmium than in control treatments (P=0.008). These results demonstrate the capacity of An. gambiae s.s. to develop tolerance to increased levels of heavy metal challenge. The results also confirm the potential of heavy metal-responsive genes in mosquitoes as possible bio-indicators of heavy metal environmental pollution. How the tolerance and expressions relate to An. gambiae s.s. fitness and vectorial capacity in the environment remains to be elucidated.Item Field Responses of Tsetse Flies (Glossinidae) and Other Diptera to Oils in Formulations of Deltamethrin(2003) Mireji, PO; Mabveni, AM; Dube, BN; Ogembo, JG; Matoka, CM; Mangwiro, TNCInvestigations were conducted to establish field responses of Glossina pallidipes, G. m. morsitans, muscoids and tabanids to castor, raw linseed, paraffin and chlorinated paraffin oils in deltamethrin suspension concentrate (sc) formulation, through randomised Latin square experiments. Tsetse landing responses on targets treated with 400 ml/m2 of any of the oils in 2 g/m2 deltamethrin formulation were significantly lower than on non-oil-containing deltamethrin formulations, for both G. pallidipes (F(4,32) = 4.855, P = 0.00357) and G. m. morsitans (F(4,32)=2.421, P = 0.06862). The landing response indices, relative to the control formulation without oil, were 0.60, 0.70, 0.61 and 0.41 in G. pallidipes and 0.92, 0.82, 0.75 and 0.42 in G. m. morsitans and for paraffin, chlorinated paraffin, castor and raw linseed oils respectively. Glossina pallidipes and G. m. morsitans landing responses were inversely proportional to raw linseed oil concentrations. None of the oils significantly affected muscoid (F(4/32) = 1.6959, P = 0.1753) or tabanid (F(4,32) = 1.7546, P = 0.1624) landing response, or tsetse fly resting persistence (F(4,32) = 0.9641, P = 0.4406) on the targets. The reduced tsetse fly response to targets treated with any of the oils can be attributed to adverse effect of the oil treatments on the tsetse fly olfactory responses to the targets. Since the oil formulations reduce target efficiency by reducing tsetse responses to the targets, application of the oil formulations on targets deployed in G. pallidipes and G. m. morsitans control programmes is not recommended.Item Gender differences in cardiovascular disease: The effects of estrogen(2005) Mbai, Fiona N; Hamilton, Karyn L; Knowlton, Anne AEstrogen and its therapeutic application in cardiovascular disease are highly controversial. There has been a paucity of basic research on estrogen and its molecular effects, which has weakened the underpinnings of clinical trials of estrogen treatment. In the past 10 years, much has been discovered about both the genomic and nongenomic effects of estrogen. The identification of at least three distinct receptors for estrogen, as well as the development of drugs with varying binding affinities for different receptors, has created exciting therapeutic possibilities.Item Genome Sequence of the Tsetse Fly (Glossina morsitans): Vector of African Trypanosomiasis(2014) Marucha, KK; Masiga, DK; Meuti, ME; Mireji, POTsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein–encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.Item Heavy metals in mosquito larval habitats in urban Kisumu and Malindi, Kenya, and their impact(2008) Mireji, PO; Keating, Joseph; Hassanali, Ahmed; Mbogo, Charles M; Nyambaka, Hudson; Kahindi, Samuel; Beierf, John CConcentrations and distribution of cadmium, chromium, copper, iron, lead, manganese and zinc in mosquito larval habitats in urban Kisumu and Malindi, Kenya and their effect on the presence of Anopheles gambiae, Aedes aegypti, Culex quinquefasciatus and Anopheles funestus larvae were investigated. Manganese and iron were the most prevalent heavy metals in water of larval habitats in urban Kisumu and Malindi, respectively. Iron was the most prevalent heavy metal in bottom sediments in larval habitats in both cities. The highest concentrations of all heavy metals, except cadmium and iron, were recorded in the poorly planned–well drained stratum in the two cities. All heavy metals were more concentrated in human-made than in natural larval habitats. Copper was positively associated with the presence of Ae. aegypti, and lead was associated with the presence of An. gambiae and Ae. aegypti in urban Kisumu. Absence of significant correlation between the other metals and mosquito species in both cities, despite relatively high concentrations, suggest that the local larval populations, including key malaria vectors have adapted to the detected levels of these metals.