RP-Department of Biological Sciences

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Assessment of Physicochemical Changes during Composting Rice Straw with Chicken and Donkey Manure
(Springer Science + Business Media, 2019) Karanja, Anncarol W.; Njeru, Ezekiel M.; Maingi, John M.
Purpose Traditional methods of composting are limited in timely production of good-quality compost due to recalcitrant nature of materials of plant origin. This study focused on evaluating the use chicken and donkey manure as starter cultures to biostimulate bioconversion of rice straw into bioorganic fertilizer. Use of starter cultures would enhance composting as a strategy for rice straw management to enhance soil fertilization and reduce environmental pollution. Methods In this study, chicken manure and donkey manure were used as starter cultures to enhance bioconversion of recalcitrant and abundant rice straw in Mwea, the main rice-producing area in Kenya. Treatments of the study included rice straw co-composted with chicken manure (T1), rice straw co-composted with donkey manure (T2) and a control (T0) consisting of un-treated rice straw. Temperature, pH and electrical conductivity (EC) were monitored throughout the composting period. Resultant compost types were characterized in respect to their macro-nutrient concentrations, cation exchange capacity, pH and heavy metal content. Results Levels of temperature, pH and EC among the treatments of the study revealed signifcant diferences at 5% level of confdence using Tukey’s test. The three resultant compost types obtained were also physicochemically diferent as revealed by analysis of variance of cation exchange capacity, phosphorus, nitrogen and carbon content. Conclusion Results indicated that use of chicken and donkey manure signifcantly improved the composting process and the quality of resultant compost.
Biology of the Wild Silkmoth Anaphe panda (Boisduval) in the Kakamega Forest of Western Kenya
(Hindawi Publishing Corporation, 2012) Kioko, E. N.; Mueke, J. M.; Raina, S. K.; Mbahin, N.
A study on the life cycle of the silkmoth Anaphe panda (Boisduval) was conducted in two different habitats of the Kakamega Forest in western Kenya: Ikuywa, an indigenous forest, and Isecheno, a mixed indigenous forest. Eggs were laid in clusters, and the incubation period ranged from 40 to 45 days. Larvae fed on Bridelia micrantha (Hochst) and passed through seven instars. The developmental period took between 83 to 86 days in the dry season and 112 to118 days in the rainy season. The pupal period ranged between 158 and 178 days in the rainy season and, on the other hand, between 107 and 138 days in the dry season. But the later caught up in development with those that formed earlier. Moths emerged from mid-October until mid-May. Longevity of adult Anaphe panda moths took between 4 and 6 days, but generally females seemed to live longer than males. The moth also seems to have higher lifespan in the indigenous forest compared to the mixed indigenous forest.
Bionomics of the acarophagous ladybird beetle Stethorus tridens fed Tetranychus evansi
(Wiley, 2007-06-02) Ogol, C.K.P.O.; Fiaboe, K. K. M.; Gondim Jr, M. G. C.; De Moraes, G. J.; Knapp, M.
The bionomics of Stethorus tridens Gordon fed Tetranychus evansi Baker & Pritchard were studied in the laboratory. The number of prey consumed by S. tridens increased with increasing instar levels and the total mean number consumed during immature development was 184.1 ± 18.02 T. evansi nymphs per individual. For adult male and adult female, the daily consumption was 41.3 ± 0.80 and 67.8 ± 1.69 nymphs, respectively. Stethorus tridens successfully developed to adulthood between 20 and 30°C but failed at 10, 15 and 35°C. The lower thermal threshold for egg-to-adult development estimated via linear regression and the modified Logan model was 9.2 and 8.1°C, respectively. The optimum and maximum temperatures for egg-to-adult development were around 29–31 and 32.9°C, respectively. Egg to adult development time was 23.8 ± 0.24, 17.4 ± 0.22, 16.2 ± 0.22 and 12.1 ± 0.16 days at 20, 24, 27 and 30°C, respectively. At 27°C, the sex ratio, expressed as the proportion of females, was 0.54 and the mean preoviposition, oviposition and postoviposition periods were 10.3 ± 0.67, 31.2 ± 4.74 and 30.2 ± 5.24 days, respectively. The oviposition rate was 4.0 ± 0.16 eggs/female/day with a female mean longevity of 71.6 ± 6.19 days and an intrinsic rate of natural increase of 0.104. The potential of S. tridens as a candidate natural enemy of T. evansi is discussed.
Biotaxonomy of cassava green spider mites, Mononychellus spp. (Tetranychidae): “Life type” as a possible biological criterion for their identification
(Cambridge University Press, 2011-09-19) Ogol, C.K.P.O.; Oloo, G. W; Kambona, K.O.
The life patterns of cassava green spider mite populations were compared using characteristics of spinning behaviour and other associated biological parameters so as to determine the possibility of using these criteria for separating closely related forms or populations of Mononychellus complex of species. These included web structure and density, preferred site for oviposition, feeding, walking, defecation, quiescence, spinning behaviour during walking and type of egg cover. Of these, preferred site for feeding, walking, quiescence and spinning behaviour during walking were found to be consistent and could possibly be used in comparative studies on different mite populations. The surface structure of the leaves i.e. pubescence, and mite population density were found to affect some of the behaviour patterns. Detailed studies on the influence of other factors, such as host plant variety, stage of plant growth, age of leaf colonized, weather, etc. will be necessary to determine the usefulness of these biological criteria in separating sympatric and allopatric populations of the mite.
Chemistry & HIV and AIDS Integrated course module (Kenya)
(United Nations Educational Scientific and Cultural Organization, 2015) Ng'ang'a, Z. W; Imbuga, M; Thoruwa, L. C.; Ochanda, A.; Andam, A. B.; Kwofie, T. B.; Meyer, D
Correlation of melting temperature and cesium chloride buoyant density of bacterial deoxyribonucleic acid.
(American Society for Microbiology, 1970) Igambi, L.; Mandel, M.; Bergendahl, J.; Dodson, M. L. Jr.; Scheltgen, E.
Samples of bacterial deoxyribonucleic acid from bacteria having guanine plus cytosine (GC) contents in the range of 27 to 72 moles per cent GC were analyzed by optical melting (T(m)) and equilibrium buoyant density methods. The relation between these properties is shown to be linear. The relative value of 1.99 moles per cent GC per degree C change in T(m) is calculated, and a reference method for the calculation of GC contents relative to a standard is derived.
Dynamics of immature stages of Anopheles arabiensis and other mosquito species (Diptera: Culicidae) in relation to rice cropping in a rice agro-ecosystem in Kenya
(Wiley, 2006) Mwangangi, Joseph; Shililu, Josephat; Muturi, Ephantus; Gu, Weidong; Mbogo, Charles; Kabiru, Ephantus; Jacob, Benjamin; Githure, John; Novak, Robert
We determined changes in species composition and densities of immature stages of Anopheles arabiensis mosquitoes in relation to rice growth cycle in order to generate data for developing larval control strategies in rice ecosystems. Experimental rice paddies (6.3m x 3.15m) exposed to natural colonization of mosquitoes were sampled weekly for two rice growing cycles between February 2004 and March 2005. Overall, 21,325 Anopheles larvae were collected, of which 91.9% were 1st and 2nd instars and 8.1% were 3rd and 4th instars. An. arabiensis was the predominant species (84.1%) with other species, An. pharoensis (13.5%), An. funestus (2.1%), An. coustani (0.3%), and An. maculipalpis (0.1%) accounting for only a small proportion of the anophelines collected. Culex quinquefasciatus (65.7%) was the predominant species among the non-anopheline species. Others species collected included: C. annulioris (9.9%), C. poicilipes (7.3%), C. tigripes (7.2%), C. duttoni (0.6%), Aedes aegypti (5.3%), Ae. cumminsii (3.5%), and Ae. vittatus (0.7%). The densities of the major anopheline species were closely related to rice stage and condition of the rice field. An. arabiensis, the predominant species, was most abundant over a three-week period after transplanting. Low densities of larvae were collected during the late vegetative, reproductive, and ripening phases of rice. An increase in larval density ten days post-transplanting was found to correlate with the application of fertilizer (sulphate of ammonia). Culicine and aedine species densities were significantly higher during the post-harvesting period. Our results suggest that the transplanting stage is favorable for the growth of immature stages of An. arabiensis and provides a narrow window for targeted larval intervention in rice
Effect of Predation on Anopheles Larvae by Five Sympatric Insect Families in Coastal Kenya.
(Medknow Publications, 2013-03) Kabiru, Ephantus W.; Kokwaro, E. D.; Muiruri, S. K.; Mwangangi, J. M.; Carlson, J.; Githure, J.; Mbogo, C. M.; Beier, J. C.
BACKGROUND & OBJECTIVES: The use of insecticides to eliminate mosquito larvae from ground pools may disrupt atural predator-induced control of mosquito larvae. Detrimental effects on predators may be directly from toxicity or by eliminating prey organisms. Identifying the principal predators responsible for mosquito suppression is needed to select non-target indicator species for insecticide studies. In this study, we sought to determine trophic level interactions between predators and immature stages of Anopheles gambiae Giles mosquitoes under experimental conditions in the coastal region of Kenya. METHODS: To identify effective predation pattern, a series of prey choice experiments was conducted. The relative abilities of five common species of aquatic insects found in the malaria-endemic coastal region of Kenya were assessed in a series of experiments. Experiments were conducted in semi-field conditions at Jaribuni, near the sites of insect collection. RESULTS: In single predator experiments, notonectids consumed most of the mosquito larvae; hydrometrids consumed about half of the mosquito larvae in treatments. Veliids and gerrids had significant, but small effects on larval survivorship. Dytiscids did not have a significant effect on mosquito larvae survivorship. In a two-predator experiment, notonectids significantly decreased survivorship of dytiscids without a change in suppressive effects on mosquito larvae. Of the five common predators evaluated, notonectids were clearly the most voracious consumers of mosquito larvae. The predation pressure on mosquito larvae was not affected by the addition of additional prey items, consisting of small dytiscid beetles. The importance of this notonectid species in coastal Kenya suggests that it would be a valuable non-target indicator species for insecticide studies. Hydrometrids were also efficient at consuming mosquito larvae. INTERPRETATION & CONCLUSION: Of the five common predators from the Kenyan coast evaluated in this study, notonectids were the most voracious consumers of immature mosquitoes. Their predation pressure on mosquito larvae was not affected by the addition of additional prey items, consisting of small dytiscid beetles.
Effects of Canavalia ensiformis and Mucuna pruriens intercrops on Pratylenchus zeae damage and yield of maize in subsistence agriculture
(Kluwer Academic Publishers, 2006-06) Arim, O. J.; Waceke, J.W.; Waudo, S. W.; Kimenju, J. W.
Host status of four leguminous cover crops [Canavalia ensiformis (L.) DC. (Jack bean), Crotalaria ochroleuca G. Don (Sunnhemp), Lablab purpureus L. (Hyacinth bean) and Mucuna pruriens (L.) DC. (velvet bean)] to Pratylenchus zeae Filipjev and effects of intercropping C. ensiformis and M. pruriens with Pan5195, H627 and Emap11 maize cultivars on P. zeae population and disease severity on maize were determined in greenhouse and field tests. Pratylenchus zeae significantly (P<0.05) reduced growth of C. ochroleuca by 36% but had no effect on C. ensiformis, M. pruriens and L. purpureus. While C. ensiformis, M. pruriens and L. purpureus reduced P. zeae population, C. ochroleuca increased it. In the greenhouse test, intercropping maize with C. ensiformis significantly (P<0.05) improved maize growth by up to 34%, Nematode populations in the roots of maize intercropped with either C. ensiformis or M. pruriens were significantly (P<0.05) reduced by up to 32% while nematode disease severity in these intercropping systems was reduced by up to 26%. In the field test, intercropping Emap11, Pan5195 and H627 with C. ensiformis significantly (P<0.05) increased maize grain yield by 190, 29 and 22%, respectively. Intercropping H627 with M. pruriens significantly (P<0.05) increased maize grain yield by 12%, but grain yields of Pan5195 and Emap11 declined by 79 and 40%, respectively. Root necrosis and soil nematode populations in the C. ensiformis–maize intercrop declined by up to 50 and 30%, respectively. Under pure maize stands, soil nematode populations increased by up to 35% in 90 days relative to the initial nematode population of three nematodes g−1 of fresh soil.
Effects of glucocorticoids in Leishmania major infection
(2015) Osero, B. O.; Mosigisi, A.; Ogeto, T. K.; Mugambi, R.; Ingonga, J.; Karanja, R. M.; Gicheru, M. M.; Anjili, C.
Leishmania parasites activate NF-κB which induces Th2 expression and inactivates Th1 genes thus subverting the host defense response and promotes the survival and development of the parasite in macrophages. Macrophages were treated artificially with glucocorticoids and incubated with Leishmania promastigotes. Interleukin 1 β, Tumor necrosis factor- α and inhibitory nitric oxide synthase gene levels were measured using real time PCR and parasite development monitored in vitro. Tumor necrosis factor- α and nitric oxide synthase genes were down-regulated and Interleukin 1 β upregulated in macrophages treated with dexamethasone and hydrocortisone drugs when compared to those treated with lipopolysaccharide and untreated. Dexamethasone treated macrophages had significantly low number of amastigotes compared to hydrocortisone and lipopolysaccharide (p=0.0006). Dexamethasone showed high reduction of infection rates in macrophages as compared to hydrocortisone and lipopolysaccharide treated macrophages, however not significant (p=0.054). With further clinical studies in humans, dexamethasone may be used in the control of leishmaniasis. Keywords: Glucocorticoids, NF-kB, infection rates, amastigotes, macrophages
The efficacy of some medicinal plants used locally within Transmara west, Narok County, Kenya against selected Enterobacteria and Candida
(International Organization of Scientific Research, 2017) Nyang’au, Hesbon Omwoyo; Maingi, John; Kebira, Anthony
The bacterial family Enterobacteriaceae and fungal genus Candida have continued to be a great challenge worldwide including resistance to antibiotics and relapse of infections mediated by them. Among these organisms, Salmonella typhi, Shigella species, Klebsiella pneumoniae and Escherichia coli strains have emerged as the most frequent cause of diarrheal illnesses which account for an annual mortality rate of 4.6 million people worldwide and many other infections. Candida albicans has been reported as a causative agent of all types of candidiasis. In the present study, the efficacy of plants commonly used plants in Transmara west, Kenya against these microbes was investigated. An ethnobotanical survey using semi-structured questionnaire was done. Plant extracts were obtained through methanolic extraction. Antimicrobial susceptibility assay was done using Kirby Bauer disk diffusion technique. Minimum inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) for the bacterial test stains and Minimum Fungicidal Concentration (MFC) for C. albicans were determined using microtitre broth dilution method. Phytochemical tests were done using standard procedures. The study validates the ethno-medicinal use of Pterolobium stellatum, Rhamnus prinoides, Phyllanthus urinaria, Carissa edulis, Clutia abyssinica, Clerodendrum rotundifolium, Clerodendron myricoides and Dovyalis abyssinica and recommends consideration for the use of the studied plants as possible sources of antimicrobial agents in the development of drugs for treatment of Enterobacteria and Candida related infections.
Hepatitis B Virus Sero-profiles and Genotypes in HIV-1 Infected and Uninfected Injection and Non-injection Drug Users from Coastal Kenya
(BioMed Central, 2015) Kilongosi, Mark W.; Budambula, Valentine; Lihana, Raphael; Musumba, Francis O.; Nyamache, Anthony K.; Budambula, Nancy L. M.; Ahmed, Aabid A.; Ouma, Collins; Were, Tom
Background: Information about HBV sero-markers, infection stages and genotypes in HIV-1 infected and uninfected injection and non-injection drug users (IDUs) in Kenya remains elusive. Methods: A cross-sectional study examining HBV sero-marker, infection stages and genotypes was conducted among HIV-1 infected and uninfected, respectively, IDUs (n = 157 and n = 214) and non-IDUs (n = 139 and n = 48), and HIV-1 uninfected non-drug using controls (n = 194) from coastal, Kenya. HBV sero-marker and infection stages were based on HBV 5-panel rapid test plasma sero-reactivity. DNA was extracted from acute and chronic plasma samples and genotypes established by nested-PCR and direct sequencing. Results: HBsAg positivity was higher in HIV-1 infected IDUs (9.6 %) relative to HIV-1 uninfected IDUs (2.3 %), HIV-1 infected non-IDUs (3.6 %), HIV-1 uninfected non-IDUs (0.0 %) and non-drug users (2.6 %; P = 0.002). Contrastingly, HBsAb positivity was higher in HIV-1 uninfected IDUs (14.6 %) and non-IDUs (16.8) in comparison to HIV-1 infected IDUs (8.3 %), and non-IDUs (8.6 %), and non-drug users (8.2 %; P = 0.023). HBcAb positivity was higher in HIV-1 infected IDUs (10.2 %) compared to HIV-1 uninfected IDUs (3.3 %), HIV-1 infected non-IDUs (6.5 %), HIV-1 uninfected non-IDUs (2.1 %) and non-drug users (4.6 %; P = 0.038). Acute (5.7 %, 1.4 %, 0.0 %, 0.0 % and 1.5 %) and chronic (5.1 %, 0.9 %, 3.6 %, 0.0 % and 1.5 %) stages were higher in HIV-1 infected IDUs, compared to HIV-1 uninfected IDUs, HIV-1 infected and uninfected non-IDUs and non-drug users, respectively. However, vaccine type response stage was higher in HIV-1 uninfected IDUs (15.4 %) relative to HIV-1 infected IDUs (6.4 %), and HIV-1 infected (6.5 %), and uninfected (10.4 %) non-IDUs, and non-drug users (5.7 %; P = 0.003). Higher resolved infection rates were also recorded in HIV-1 uninfected IDUs (11.2 %) compared to HIV-1 infected IDUs (8.3 %), and HIV-1 infected (7.2 %), uninfected (6.3 %) non-IDUs, and non-drug users (6.7 %; P = 0.479), respectively. Only A1 genotype showing minimal diversity was detected among the study participants. Conclusion: HBV sero-markers and infection staging are valuable in diagnosis and genotyping of HBV infections. Among IDUs, higher HBsAg and HBcAb positivity in HIV-1 infected and higher HBsAb positivity in HIV-1 negative IDUs suggests frequent exposure. Additionally, HBV genotype A is the dominant circulating genotype in both high and low risk populations of Kenya.
Life tables, key factor analysis and density relations of natural populations of the spotted maize stemborer, Chilo partellus (Lepidoptera: Crambidae), under different cropping systems at the Kenyan coast
(Cambridge University Press, 2005-06) Ogol, C.K.P.O.; Midega, C. A.O.; Overholt, W. A.
Studies were conducted at Mtwapa, in the coastal area of Kenya, during the long and short rains of 1999 and 2000 to evaluate interaction of mortality factors in lowering Chilo partellus (Swinhoe) populations in diverse agroecosystems. Treatments consisted of hedgerows of leucaena only, gliricidia only, alternating rows of leucaena and gliricidia, and three plots without trees. During the cropping seasons, maize was planted between the hedgerows while a row of cowpea was planted between the rows of maize. One of the plots without trees was planted to an intercrop of maize and cowpea. The remaining two plots without trees were planted to maize alone, one of which was mulched. The treatments were laid out in a randomized complete block design with four replications. There was no evidence of enhanced mortality in the more diverse systems indicating that the vegetation structure and cultural treatments studied did not enhance activity levels of C. partellus mortality factors. The highest mortality occurred in the early and medium larval stages in all treatments. This mortality was attributable to ‘disappearance’, which represented mortality from sources other than parasitism. The total real generation mortality showed that from the initial cohort of first and second instar larvae, less than 10% of C. partellus survived to adult stage under field conditions in all the treatments. Mortality by Cotesia sesamiae Cameron and Cotesia flavipes (Cameron) was very minimal, indicating the parasitoids were not important mortality factors of C. partellus under the cropping systems studied. Their effects were also not influenced by the cropping systems studied.
Molecular Characterization of HIV Type 1 among HIV-Infected Respondents in a Cohort Being Prepared for HIV Phase III Vaccine Clinical Trials, Western Kenya.
(PubMed, 2011-03) Mbithi, J. N.; Oyaro, M.; Oyugi, F.; Laten, A.; Anzala, O.; Engelbrecht, S.
Kenya is one of the sub-Saharan African countries affected by HIV-1 infection and AIDS. We investigated HIV-1 genetic diversity in 130 individuals from Busia, Bungoma, and Kakamega in western Kenya as part of an HIV-1 vaccine feasibility study in preparation for Phase III efficacy clinical trials. After RNA extraction the partial gag (484 bp) and env (1297 bp) regions were amplified and directly sequenced. Phylogenetic analysis was done using MEGA version 4 and recombinants were identified using the jpHMM tool and phylogenetic analysis. HIV-1 sequences were amplified from 122 of the 130 samples, 118 (90.8%) from the gag region and 78 (60 %) from the env region and 74 samples (56.9%) from both the gag and env regions. Of these sequenced on both regions, 51.4% were subtype A, 9.4% subtype D, 1.4% subtype C, 4.1% subtype G, and 33.7% were discordant and thus possible recombinants, including A1/C, A1/D, A1/A2, and A2/C. The jpHMM tool indicated a further two samples with CD and BD breakpoints within the env gene and one within the gag gene (A1C). An additional sample had an A1D breakpoint in the gag gene, but the envelope was not amplified. HIV-1 subtype diversity in western Kenya should be considered in vaccines designed for clinical trials in this region and this genetic diversity should be continuously monitored.
Parasitoids of the African wild silkmoth, Gonometa postica (Lepidoptera: Lasiocampidae) in the Mwingi forests, Kenya
(Wiley, 2009-07) Mueke, J. M.; Fening, K. O.; Raina, S. K.
Gonometa postica Walker produces silk of high quality, but it is affected by parasitoids attack. A study on the parasitism of G. postica larvae and pupae on host and non-host plants were undertaken for the first and second generations, corresponding to the long (March–May) and short (October–December) rainy seasons in 2006 at six field sites, three each in the Imba and Mumoni forests of Mwingi, eastern Kenya. All freshly spun cocoons of G. postica were sampled at each site from a total of 100 trees of host plants and other non-host plants where they have migrated before pupation. The cocoons were kept individually in fine net-sealed plastic vials to determine percentage parasitism. Two dipterans and four hymenopteran larval–pupal parasitoids were identified from the two forests. The most common parasitoids were Palexorista sp. (Diptera: Tachinidae) and Goryphus sp. (Hymenoptera: Ichneumonidae) with parasitism ranging from 1.8 to 32.7% and 2.2 to 7.5%, respectively. Parasitism varied significantly according to host or non-host plants, seasons and sites. This study indicates that, of the six parasitoid species recovered, only two had a significant impact in reducing the quality of the cocoons.
Parental awareness of hearing impairment in their school-going children and healthcare seeking behaviour in Kisumu district, Kenya
(Elsevier, 2007-03) Otieno, S.; Ogol, C.K.P.O.; Omondi, D.; Macharia, I.
Background Hearing-impaired children who are identified early and appropriately managed have improved outcomes in speech, language, cognitive and social development. Enhanced parental awareness of their child's hearing disability, behavioral, developmental and psychosocial limitations is essential to sustaining timely detection and appropriate intervention. Additionally, availability of services for diagnosis, treatment and habilitation would improve the demand for pedaudiological care in this community. Objective To describe level of parental awareness of childhood HI and the pattern of access to and utilization of ambulatory care services. Subjects Thirty-three parents of lower primary school-going children who failed audiometric screening from sampled schools in Kisumu district, western Kenya. Main outcome measures First person to detect HI, age of child at first suspicion of HI, source of ambulatory health care and use of the health care facilities. Results The prevalence of HI was 2.48%. Most parents/guardians (69.7%) were aware of their child's hearing impairment. Of these, 63.6% were first to detect HI in the pupils, while 30.3% were detected by screen. Most children (57.2%) were first recognized with (HI) after age 2 years. The mean age at identification was 5.5 years. The median travel distance to the preferred health care facility was 2 km (IQR 1–2.5). Parents seldom sought or lacked help for their hearing-impaired children. Of 27.3% who asked for hearing assessment, 9.1% received some counsel on HI and 12.1% received medication, one (3%) was referred for audiological assessment and none used a hearing aid. Use of health facilities for maternal care was (65.7%) and immunization (62.9%). Conclusions Despite adequate parental awareness of chronic childhood disability, health facilities were underutilized. This indicates the need to further stimulate and maintain a desirable level of uptake of services for diagnosis, treatment and habilitation of childhood HI, while sustaining delivery of effective and acceptable high quality paediatric care.
Physico-chemical Analysis, Microbial Isolation, Sensitivity Test of the Isolates and Solar Disinfection of Water Running in Community Taps and River Kandutura in Nakuru North Sub-county, Kenya
(Academic Journals, New York, 2015) Waithaka, Paul N.; Maingi, John Muthini; Nyamache, Anthony Kebira
Nakuru North sub-county is a peri-urban area which has both dry and wet seasons. Its residents rely mostly on untreated water sources for daily water needs due to unreliable water supply from the urban council. However, this water has not been evaluated on its quality despite residents solely depending on it. This study was aimed at determining the physico-chemical and bacteriological quality of water drawn from River Kandutura and water taps in Nakuru North subcounty. In addition, the study was aimed at carrying out sensitivity test of the isolates to antibiotics and determining effectiveness of solar disinfection in water treatment. A total of 510 water samples; river (255) and taps (255) were collected and analyzed between January and December 2013. Antimicrobial sensitivity test was carried out using Kirby Bauer disk diffusion test. Out of five hundred and ten (510) samples examined for microorganisms, 36.86 % (188/510) were positive for E. coli, Shigella and Salmonella. Water used by Nakuru North sub-county residents is highly contaminated thus posing public health risk. Solar disinfection experiment indicated a possibility of effective decontamination of water up on exposure to sun light for 3-5 h. E. coli showed the highest resistance (26.3 %) followed by Salmonella (17.4 %) while Shigella showed the least (17.1 %). However, there was no significant deference (p=0.98) in resistance among total coliforms, Total heterotrophic and Salmonella at 0.05 level of significant. There is a need to enforce laws and policies on proper waste disposal as part of water pollution control
Plant parasitic nematodes: a threat to vegetable production in Kenya
(African Crop Science Society, 2011) Maina, J. M.; Waceke, J. W.; Kariuki, G. M.
A survey of plant parasitic nematodes (PPN) associated with cabbage was carried out in selected agro-ecological zones (AEZs) in Kenya to determine PPN density, distribution and farmer’s awareness of nematodes associated problem. Sixty cabbage farms were sampled and nematode assays on root and soil samples were carried out. Nematode population density differed significantly (P<0.05) across all the AEZs with Upper highland 1 (UH1a) recording the highest PPN population and UM1 recording the lowest. Nematodes from cabbage roots also differed significantly (P<0.05) across AEZs with Upper highland 1 (UH1b) recording the highest population density of 60 nematode 10g-1 of dry roots and UM1 having 1.2 nematodes 10g-1 of dry roots. Pratylenchus was the most abundant nematode in all AEZs. Only 3% of sampled farmers were aware of nematodes associated problems and none of them applied any nematode management practice. Key words: Agro-ecological zones, cabbage, farmer’s awareness
Profiling Antibiotic Resistant Bacteria and Antibiotic Residues in Raw Chicken Products Sold Around Kenyatta University, Kenya
(International Journal of Applied Biology, 2020) Nganga, Daniel Kamua; Musonye, Harry Asena; Kamande, Patrick Kamau; Kamau, Lucy Muthoni
Antibiotic resistant bacteria and antibiotic residues are a serious safety problem for animal food products. Poultry products have been long recognized as a reservoir for antibiotic resistant commensals and pathogens. Antibiotic residues ingested via food animal products expose gut micro-flora to low concentrations of antibiotics, which promote antibiotic resistance. However, there is limited knowledge regarding the potential of chicken products to act as a transmission corridor for the spread of the antibiotic resistant bacteria and antibiotic residues. The present study aimed at profiling antibiotic resistant bacteria and antibiotic residues in raw chicken products sold around Kenyatta University, Kenya. A total of 32 meat and egg samples were randomly collected from two study sites; KM and KU. Antibiotic residues in the study samples were detected using two microbiological techniques with Bacillus subtilis , Staphylococcus aureus, Escherichia coli , and Salmonella typhi as test organisms. Selective and differential media were used to isolate Escherichia coli , Salmonella and Shigella from the samples. Antibiotic susceptibility testing of these isolates against commonly used antibiotics was done using Kirby-Bauer antibiotic discs diffusion method. Of the total samples tested, 87.50% meat and 100% egg samples showed presence of antibiotic residues. The mean colony forming units (CFUs) of meat samples from KM (190.25 x 10² CFU) was higher than that of KU (104.96 x 10² CFU). Eggs from KM showed contamination (158.88 x 10² CFU) than those sampled (108.29 x 10² CFU) within the university outlets. Escherichia coli , Salmonella and Shigella, were resistant to ampicillin. Escherichia coli showed intermediate resistance to tetracycline while Escherichia coli and Shigella showed intermediate resistance to amikacin. This study reveals the presence of antibiotic residues and antibiotic resistant bacteria in chicken meat and eggs sold in the study area. Knowledge generated from this study is helps to develops effective strategies to control antibiotic resistance. ISSN : 2580-2410 eISSN : 2580-2119 Profiling Antibiotic Resistant Bacteria and Antibiotic Residues in Raw Chicken Products Sold around Kenyatta University, Kenya Daniel Kamua Nganga1*, Harry Asena Musonye1, Patrick Kamau Kamande2, Lucy Muthoni Kamau 3 1 Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, Nairobi, Kenya 2 Department of Food Nutrition and Dietetics, Kenyatta University, Nairobi, Kenya 3 Department of Animal Health and Production, Kenyatta University, Nairobi, Kenya Introduction The burden of antibiotic resistance (ABR) has a negative impact on the health and socio-economic status of the people (Ferri et al., 2017). The emergency and spread of ABR is O PEN ACCESS International Journal of Applied Biology
Response of a wild-type and modern cowpea cultivars to arbuscular mycorrhizal inoculation in sterilized and non-sterilized soil
(Taylor & Francis, 2018) Oruru, Marjorie Bonareri; Njeru, Ezekiel Mugendi; Pasquet, Remy; Runo, Steve
Cowpea is an important crop that serves as a legume and vegetable source to many smallholder farmers in sub-Saharan Africa. Soil fertility is a significant limitation to its production thus; inoculation with beneficial soil biota such as arbuscular mycorrhizal fungi (AMF) could improve its performance. However, plant–AMF interaction could vary based on crop cultivar hence affecting overall crop production. The present study aimed at determining the effect of AMF inoculation and soil sterilization on root colonization and growth of a wild-type and three modern cowpea cultivars grown by smallholder farmers in Kenya. Potted cowpea plants were inoculated with a commercial AMF inoculum comprising of Rhizophagus irregularis, Funneliformis mosseae, Glomus aggregatum and Glomus etunicatum and maintained in a greenhouse for 40 days. After harvesting, mycorrhizal colonization, nodule number and dry weight, root and shoot dry weights, nitrogen (N,) phosphorus (P) and potassium (K) content were determined. Interestingly, the modern cultivars showed significantly (p < 0.001) higher root colonization, nodulation, shoot P and N compared to the wild-type cultivar. Moreover, a strong positive correlation between AMF root colonization and shoot P (r2 D 0.73, 0.90, p < 0.001), AMF root colonization and shoot N (r2 D 0.78; 0.89, p < 0.001) was observed in both sterilized and non-sterilized soil, respectively. Soil sterilization affected root colonization and growth parameters with plants grown in non-sterilized soil performing better than those grown in sterilized soil. This study provides major evidence that modern cowpea cultivars are still responsive to mycorrhizal inoculation suggesting that modern breeding programs are not deleterious AMF symbiosis.

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