Department of Biological Sciences

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Antimalarial pyronaridine resistance may be associated with elevated MDR-1 gene expression profiles but not point mutation in Plasmodium berghei ANKA isolates
(African Journal of Biochemistry Research, 2020-08) Kimani, Shadrack Kanyonji; Shume, Jacob Manyiwa
The selection of resistance is inevitable whenever chemotherapy is necessary for pathogen control. Notably, Plasmodium falciparum has developed multifaceted means to overcome the toxicity of nearly all antimalarial medicines. To bypass this challenge, not only should novel drugs be developed, but the resistance mechanisms to new and existing drugs need should be fully explored. Pyronaridine is a companion drug in Pyramax® , a blend of artesunate (ASN)-pyronaridine (PRD) which is the WHO prequalified alternative for malaria treatment in the African setting. However, half-life mismatch predisposes the PRD to swift emergence of resistance especially in high malaria transmission settings. However, there are no well-characterized PRD-resistant parasite lines. Previously, stable PRD- resistant P. berghei ANKA lines were selected by in vivo drug pressure and preliminary results showed crossresistance with quinolines, therefore, hypothetically the activity of PRD and chloroquine or other quinolines may be comparable, hence, the resistance mechanisms may be parallel. Consequently, genetic polymorphisms and expression profiles of PbMDR-1 that could be associated with pyronaridine resistance were examined by PCR amplification, sequencing and transcript quantification by RT-qPCR. The transcripts level increased during resistance selection while translated PbMDR-1 sequence alignment of PRD-sensitive and PRD-resistant was the same, the expression may be linked to PRD resistance but not mutations.
Antimalarialpyronaridine resistance may be associated with elevated MDR-1 gene expression profiles but not point mutation in Plasmodium bergheiANKA isolates
(African Journal of Biochemistry Research, 2020-08) Kimani, Shadrack Kanyonji; Shume, Jacob Manyiwa
Theselectionofresistance is inevitable whenever chemotherapy isnecessaryforpathogencontrol. Notably, Plasmodiumfalciparum has developed multifacetedmeans to overcomethetoxicityof nearly allantimalarial medicines. To bypass this challenge,not only should novel drugs be developed, but the resistance mechanisms tonewandexisting drugs need should be fullyexplored.Pyronaridine is a companion drug inPyramax®, a blend of artesunate (ASN)-pyronaridine (PRD) whichistheWHOprequalifiedalternative for malariatreatment in the Africansetting. However, half-life mismatch predisposes thePRDto swiftemergence of resistanceespeciallyin high malaria transmission settings. However, there are no well-characterized PRD-resistant parasite lines. Previously, stable PRD-resistant P. bergheiANKA lines were selected by in vivo drug pressure and preliminary results showed cross-resistance with quinolines, therefore, hypothetically theactivityof PRDand chloroquine or other quinolinesmay be comparable, hence, the resistance mechanisms may be parallel. Consequently, genetic polymorphisms and expressionprofiles of PbMDR-1 that could be associated with pyronaridine resistance wereexamined by PCR amplification, sequencingand transcript quantification byRT-qPCR.The transcripts level increased during resistanceselectionwhiletranslated PbMDR-1sequence alignment of PRD-sensitive and PRD-resistant was the same, theexpressionmay be linked toPRD resistance but not mutations
Antimicrobial acitivity of extracts from Tephrosiavogelii Hook F.
(Jomo Kenyatta University of Agriculture & Technology (JKUAT), Kenya, 2006) Wanga, B. N.; Akenga, T.; Imbuga, M.; Gitonga, L.; Olubayo, F.; Namungu, P.
The dichloromethane extracts of the root and leaf of Tephrosia vogelii Hook F. (Family: Papilionaceae) grown in Kenya, were subjected to antimicrobial assays against Staphylococcus aureus, Escherichia coli and Fusarium phoseolida. The minimum inhibition concentrations (MIC) ranged between 0.25 to 6.4 μg/ml for all the microorganisms tested. The crude root and leaf extracts were also toxic to the brine shrimps, organisms used as indicators of toxicity (LC50: 0.960; 0.958μg/ml,respectively). Chromatographic separation led to the identification of (6aß, 12aß, 5'ß)-6a, 12a, 4',5'-tetra hydro-2,3-dimethoxy 5'-ß- isopropenyl–furano (3',2': 8,9)-6H-rotoxen-12-one, (rotenone) in 9.75% yield, (roots), and 11.75% (leaves). Characterisation was achieved by use of spectroscopic techniques and comparison with rotenone standard and literature data. Novel HPLC conditions for purification of rotenoids were established. The MIC of rotenone against the tested microbes was found to be 5.2 and 1.0 μg/ml for Staphylococcus aureus and Escherichia coli respectively, while the LC50 against the brine shrimps was found to be 3.20 μg/ml. The findings indicate that the extracts of T. vogelii contain metabolites that have antimicrobial activity comparable to other medicinal plants.
Bioecology of thrips in French bean growing ecosystem in Kenya
(2012-10-31) Gitonga, Linus Muthuri
Studies on the bioecology ofthrips on French beans were carried out at Machakos, Kaguru and JKUAT. The general objectives of this study were twofold, namely to study the biology and population dynamics of thrips on French beans and to identify and evaluate indigenous natural enemies of the thrips. Two thrips species, M sjostedti and F occidentalis were found throughout the year on French bean crops in all localities of the study. Their population peaks occurred at different times in the course of the year. Populations of M sjostedti peaked after the rains while those of F occidentalis occurred during the hot and dry months of the year at all the localities. Studies on the movements of thrips, into and out of the French bean crops showed that colonization by both species begins soon after germination and that both species preferred the flowers to other plant parts. F occidentalis was found to thrive equally well on the leaves, unlike M sjostedti which only inhabited flower buds and flowers. During the pre-flowering phase ofthe crop, M sjostedti were found on the terminal buds from where they moved to the flowers immediately after the onset of flowering. Most first instar larvae emerged from the pods and flowers. Petioles, leaves, flower buds, flowers and pods were used as oviposition substrates by the thrips.to varying extents. Analysis of the spatial distribution showed both species to be significantly aggregated in the respective plant parts. Laboratory studies indicated that developmental period decreased with an increase in temperature for all the stages of M sjostedti and F. occidentalis. Developmental threshold temperatures were calculated as 9.6 and 9.0 for M sjostedti and F. occidentalis respectively. Development from egg to adult required 212.0 and 256.8 Degree Days for M sjostedti and F. occidentalis respectively. However, at 15?C and 300C, mortality rates for all the developmental stages were higher for M sjostedti than F. occidentalis. The highest mortalities were recorded for the first instar larvae for both species, ranging from 15% to 42% and 11 % to 30% for M sjostedti and F. occidentalis respectively. Pre-pupae and pupae had the lowest mortality rates. An indigenous anthocorid bug, Orius albidipennis was found throughout the year in all the three field sites. Studies on the functional responses of 0. albidipennis to M sjostedti showed that more second instar larvae than adult M sjostedti were killed at all the temperature profiles and densities. With increase in temperature, more second instar larvae and adult M sjostedti were killed. High f2 values shows that both Types I and IT functional responses provided good fit for the data at 15?C, 25?C and 28?C. Attack rates also increased with an increase in temperature. Mortality rates of the 0. albidipennis nymphal instars decreased from the first to the 5th instar at all the temperatures. The mortality rates at 25?C were lower than at 20?C and 30?C for all the nymphal instars except the first instar. Temperatures had a significant effect on the pre-oviposition period, which decreased with an increase in temperature. The eggs took long to hatch at 20?C. Developmental periods of each of the nymphal instars decreased with an increase in temperature. An indigenous larval endoparasitoid of thrips, Ceranisus menes, was found throughout the year in the three localities and its population peaks occurred in the late and early months of the year, from October to April. A closer correlation was found between C. menes and F. occidentalis than with M sjostedti. At JKUAT, percentage parasitism, over the entire crop cycle, ranged from 3.5% to 19.5% and peaked in the months of Marchi April. The lowest percentage parasitism coincided with the period of the highest M sjostedti infestation on French beans. Linear regression analysis showed a density dependence relationship between parasitism and larval density. Laboratory experiments showed that C. menes successfully parasitized and completed development in both M sjostedti and F. occidentalis. Developmental times of C. menes in M sjostedti and F. occidentalis were not significantly different.
Biological impact of the exotic parasitoid, Diadegma semiclausum (Hellen), of diamondback moth, Plutella xylostella L., in Kenya
(Karatina University, 2006-08) Momanyi, Caleb; Loehr, Bernhard; Gitonga, Linus
Diadegma semiclausum (Hellen) was introduced to Kenya from Taiwan for the control of diamondback moth (DBM), Plutella xylostella L., and released for the first time in July 2002. Seven and twelve months after release, field mortality studies using the cage exclusion method were conducted at two release sites (Werugha/Taita Hills and Tharuni/Central Kenya). Four treatments were applied: fully closed and partially open cages, both with and without glue applied to the base of the plants for the exclusion of crawling predators. During this time interval, parasitism of exposed larvae rose from 15 to 60% at Werugha and from 8 to 18% at Tharuni, with a concomitant decrease of parasitism by indigenous parasitoids. Crawling predators did not seem to have an effect on mortality. Unexplained mortality increased by half between the first and second experiment at both sites, indicating additional mortality due to the parasitoid. A subsequent field simulation with different parasitoid populations showed that in the presence of parasitoids more larvae died because of abandoning the plant than due to parasitism. Dissections of larvae on the ground showed most were parasitized. Thus, it appears that mortality due to D. semiclausum is more than twice the measured rate of parasitism. Additional information on parasitism was collected from concurrently executed DBM yield loss trials. Parasitism by D. semiclausum was in the same range as in the cage exclusion method. Seven months after release, local parasitoids were present at Werugha and dominant at Tharuni, after one year, they were almost completely displaced at both locations.
Catalytic degradation of methylene blue by iron nanoparticles synthesized using Galinsoga parvifora, Conyza bonariensis and Bidens pilosa leaf extracts
(Springer Nature Switzerland, 2019-09) Makhanu, David Sujee; Kareru, Patrick Gachoki; Wanakai, Sammy Indire; Madivoli, Edwin Shigwenya; Maina, Ernest Gachui; Nyabola, Augustine Otieno
Green synthesized metallic nanoparticles are environmentally friendly, bio-compatible, and highly stable. The aim of this study was to synthesize iron nanoparticles (FeNPs) from FeCl3 solution using aqueous leaf extracts of Galinsoga parvifora (Gp), Conyza bonariensis (Cb) and Bidens pilosa (Bp) and use them in degradation of methylene blue dye. The iron nanoparticles were characterized using UV–Vis spectrophotometer, FT-IR spectrophotometer, X-ray Fluorescence (EDXRF), X-ray difractometer (XRD), and scanning electron microscope (SEM). Phytochemical screening for presence of secondary metabolites revealed presence of phenolics, phytosterols and favonoids. The total phenolic and favonoid content in Galinsoga parvifora, Conyza bonariensis and Bidens pilosa leaf extracts were 57.67±1.27, 117.13±0.03, 126.27±0.013 mg Gallic Equivalent/g of Dry Weight (mg GAE/g DW) and 39.00±0.56, 45.50±0.59, 33.13±0.81 mg Rutin Equivalent/g of Dry Weight (mg RE/g DW) respectively. The UV–Vis spectrum of FeCl3 had a shoulder at 320 nm, which disappeared upon addition of G. parvifora, C. bonariensis and B. pilosa extracts confrming formation of iron nanoparticles. Evaluation of iron content of the synthesized nanoparticles revealed that the iron content in G. parvifora, C. bonariensis and B. pilosa extracts was 51, 47 and 44% respectively. XRD data revealed presence of a large amorphous coating that masked iron peaks, though 2 theta values observed have been reported to be of iron oxides. Methylene blue degradation studies revealed that CbNPs, BpNPs and GpNPs synthesized were good biocatalysts as they degraded the dye by 86, 84.3 and 92% respectively. Therefore, green synthesized iron nanoparticles is cost efective and environmentally safe in providing insight in the environmental removal of dyes.
Compatibility of Metarhizium anisopliae isolate ICIPE 69 with agrochemicals used in French bean production
(Journal of Pest Management, 2012-04) Niassy, S.; Maniania, N.K; Subramanian, S.; Gitonga, L.M.; Maranga, R.; Obonyo, A.B.; Ekesi, S.
The compatibility of the Metarhizium anisopliae (Metschnikoff) Sorokin isolate ICIPE 69, which is being developed as a biopesticide for the control of Frankliniella occidentalis Pergande, was assessed under laboratory conditions with 12 agrochemicals including 5 insecticides (thiamethoxam, L-cyhalothrin, imidacloprid, chlorpyrifos, diazinon), 1 botanical insecticide (azadirachtin), 2 acaricides (abamectin, spiromesifen), and 3 fungicides (carbendazim, copper hydroxide, probineb) used in French bean production. The insecticides abamectin and imidacloprid were highly compatible with M. anisopliae; thiamethoxam was compatible, whereas azadirachtin and L-cyahalothrin were toxic to the fungus, adversely affecting vegetative growth and sporulation. The acaricide spiromesifen was moderately toxic, while the fungicides carbendazim, probineb, and copper-hydroxide were very toxic to the fungus. The combination of the M. anisopliae isolate ICIPE 69 with imidacloprid or thiamethoxam did not result in any synergistic or antagonistic effects to larvae of F. occidentalis. However, the combination of lower concentrations of the fungus with thiamethoxam resulted in a shorter lethal time (LT50) compared with individual treatments. Our results suggest that application of the fungus with agrochemicals has to be assessed carefully prior to any field intervention.
Current Status of Soil-Transmitted Helminths among School Children in Kakamega County, Western Kenya Prevalence and Intensity of Intestinal Parasites in School age Children in Thika District, Kenya
(Hindawi Publishing Corporation, 2016-02-17) Ngonjo, Teresia; Okoyo, Collins; Andove, Julius; Simiyu, Elses; Lelo, Agola Eric; Kabiru, Ephantus; Kihara, Jimmy; Mwandawiro, Charles
Background. School age children are at high risk of soil-transmitted helminth (STH) worldwide. In Kenya, STH infections in children remain high despite the periodic administration of anthelmintic drugs. Our study assessed the prevalence and intensity of STH in primary school-aged children in Kakamega County, western Kenya. Methodology. We carried out a cross-sectional study on a population of 731 children attending 7 primary schools in March 2014. Children aged 4–16 years were examined for STH by the quantitative Kato-Katz technique. Infection intensities were expressed as eggs per gram (epg) of faeces. Findings. Among 731 school children examined for STH, 44.05% were infected. Highest prevalence of STH was in Shitaho primary school where 107 participants were examined and 62.6% were infected with mean intensity of 11667 epg. Iyenga had the least prevalence where 101 participants were examined and 26.7% were infected with mean intensity of 11772 epg. A. lumbricoides was the most prevalent STH species with 43.5% infected, while hookworm infections were low with 1.8% infected. Conclusion. Prevalence of STHs infections in Kakamega County remains high. We recommend guidelines and other control strategies to be scaled up to break transmission cycles.
The economics and gender factor in soya bean production and profitability in Kenya: a case of smallholder farms in Western Kenya
(Int. J. Agricultural Resources, Governance and Ecology, 2017) Mutoni, Christine K.; Esilaba, Anthony O.; Mabele, Robert B.; Nyongesa, Dave
Soya-bean is among world’s major crops, cultivated for its high oil, proteins content and its ability in soil-fertility amendments. The study assessed the determinants, constraints and profitability/gross-margins of soya-bean production in Western Kenya. Multistage sampling technique and field surveys were used in data-collection process covering 370 households. Regression, gender, profitability and gross-margins were the analyses done. Results indicated gross-margins of soya-bean production within the study sites differed significantly from zero (KES 13,401-20,545); it was profitable because net profits ranged from KES 9243–13,548 for 2010. All gender-cadres shared in soya-bean production activities (5.0–18.0%). The mean technical-, allocative- and economic-efficiencies obtained were 0.78, 65 and 0.59 respectively. Smallholders/farmers’ economic-inefficiencies arose from many negativelysigned and statistically significant factors/coefficients with p-values of 0.0000– 0.0240. Increased use of these factors and county governments and other stakeholders’ interventions would positively impact smallholders’ efficiency resulting into higher output and profitability.
Evidence for Potential of Managing Some African Fruit Fly Species (Diptera: Tephritidae) Using the Mango Fruit Fly Host-Marking Pheromone
(JOURNAL OF ECONOMIC ENTOMOLOGY, 2012-12) Kachigamba, D.L.; Ekesi, S.; Ndung'u, M.; Gitonga, L.M.; Teal, P.E.A.; Torto, B.
We investigated conspecific and heterospecific oviposition host discrimination among four economically important fruit fly pests of mango in Africa (Ceratitis capitata, Wiedemann; C. fasciventris, Bezzi; C. rosa, Karsch, and C. cosyra, Walker) with regard to host-marking behavior and fecal matter aqueous solutions. The objective of the study was to get insight into the potential of managing these pests using the host-marking technique. Observations were done on mango slices marked by the flies and treated with aqueous solutions of fecal matter of the flies, respectively. In both host-marking and fecal matter experiments, C. cosyra, which is the most destructive species of the four on mango, was exceptional. It only discriminated against hosts treated with its fecal matter but with lower sensitivity while C. capitata and C.fasciventris discriminated against hosts marked by it or treated with its fecal matter and with higher sensitivity. Our results provide evidence for potential of managing some of the major fruit fly species infesting mango in Africa using the host-marking pheromone of the mango fruit fly, C. cosyra.
Functional response of Orius albidipennis (Hemiptera: Anthocoridae) to Megalurothrips sjostedti (Thysanoptera: Thripidae)
(Karatina University, 2002-05-02) Gitonga (a), Linus M.; Löhrb (b), B.; Magambo (a), J. K.; Mueke (c), J. M.
A locally available anthocorid predator, Orius albidipennis Reuter, was evaluated as a candidate biocontrol agent for Megalurothrips sjostedti Trybom, a major pest of French beans, Phaseolus vulgaris (L), in Kenya. The functional response of adult O. albidipennis to larval and adult M. sjostedti was studied at 15, 25, and 28 °C and densities of 5, 10, 20, and 30 larval and adult M. sjostedti per cage, over 24 h. More larvae and adult M. sjostedti were killed at the higher densities and with an increase in temperature. The data provided good fit to both type I and II functional response models. Attack rates increased with temperature for both the second instar larva and adult M. sjostedti. Handling times for the larvae decreased with an increase in temperature while those for the adults increased with increase in temperature. The implications of these results are discussed.
Functional response of Orius albidipennis (Hemiptera: Anthocoridae) to Megalurothrips sjostedti (Thysanoptera: Thripidae)
(Karatina University, 2002-05-02) Gitonga, Linus M.; overhalt, W.A.; Löhr, B.; Magambo, J. K.; Mueke, J. M.
A locally available anthocorid predator, Orius albidipennis Reuter, was evaluated as a candidate biocontrol agent for Megalurothrips sjostedti Trybom, a major pest of French beans, Phaseolus vulgaris (L), in Kenya. The functional response of adult O. albidipennis to larval and adult M. sjostedti was studied at 15, 25, and 28 °C and densities of 5, 10, 20, and 30 larval and adult M. sjostedti per cage, over 24 h. More larvae and adult M. sjostedti were killed at the higher densities and with an increase in temperature. The data provided good fit to both type I and II functional response models. Attack rates increased with temperature for both the second instar larva and adult M. sjostedti. Handling times for the larvae decreased with an increase in temperature while those for the adults increased with increase in temperature. The implications of these results are discussed.
Green synthesis of copper oxide nanoparticles and its efficiency in degradation of rifampicin antibiotic.
(Springer, 2023-08-28) Nzilu, Dennis Mwanza; Madivoli, Edwin Shigwenya; Makhanu, David Sujee; Wanakai, Sammy Indire; Kiprono, Gideon Kirui; Kareru, Patrick Gachoki
In recent ages, green nanotechnology has gained attraction in the synthesis of metallic nanoparticles due to their cost-effectiveness, simple preparation steps, and environmentally-friendly. In the present study, copper oxide nanoparticles (CuO NPs) were prepared using Parthenium hysterophorus whole plant aqueous extract as a reducing, stabilizing, and capping agent. The CuO NPs were characterized via UV–Vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS). The UV–Vis spectra of CuO NPs showed a surface plasmonic resonance band to occur at 340 nm. FTIR analysis revealed the presence of secondary metabolites on the surface of CuO NPs, with a characteristic Cu–O stretching band being identified at 522 cm−1. Scanning electron micrographs and transmission electron micrographs showed that CuO NPs were nearly spherical, with an average particle of 59.99 nm obtained from the SEM micrograph. The monoclinic crystalline structure of CuO NPs was confirmed using XRD, and crystallite size calculated using the Scherrer-Debye equation was found to be 31.58 nm. DLS showed the presence of nanoparticle agglomeration, which revealed uniformity of the CuO NPs. Furthermore, the degradation ability of biosynthesized nanoparticles was investigated against rifampicin antibiotic. The results showed that the optimum degradation efficiency of rifampicin at 98.43% was obtained at 65℃ temperature, 50 mg dosage of CuO NPs, 10 mg/L concentration of rifampicin solution, and rifampicin solution at pH 2 in 8 min. From this study, it can be concluded that CuO NPs synthesized from Parthenium hysterophorus aqueous extract are promising in the remediation of environmental pollution from antibiotics. In this light, the study reports that Parthenium hysterophorus-mediated green synthesis of CuO NPs can effectively address environmental pollution in cost-effective, eco-friendly, and sustainable ways.
Host plant resistance among tomato accessions to the spider mite Tetranychusevansi in Kenya
(Springer, 2011-04-11) Onyambus, G. K.; Maranga, R. O.; Gitonga, L. M.; Knapp, M.
The spider mite Tetranychus evansi has a broad range of host plants. Control of T. evansi has been a big challenge to tomato farmers due to its fast rate of reproduction, development of resistance to chemical pesticides and its ability to use weeds as alternative hosts when the tomato plants are not available. The aim of the current study was to determine the host plant acceptance and the relative contributions of trichomes in the control of the red spider mite by comparing the survival, development and oviposition rates of the red spider mite on eight tomato accessions. Leaflets from eight tomato varieties were assayed with the spider mites to determine the egg laying capacity and developmental time of the spider mites on the tomato accessions as well as the trichome densities. Densities of trichome types I, IV, V and VI varied among the tomato accessions. Variation in types I, IV and VI accounted for most of the variation in mite responses. The varieties with high densities of types IV and VI had the highest fecundity and mite development did not go beyond the larval stage. The developmental time varied significantly among the tomato accessions. The results indicated that the higher the density of trichome type I the lower the adult survival. The findings indicated possible resistance of some of the tested tomato accessions against T. evansi which is partially associated with trichomes types and density.
Influence of work environment on organizational performance in government ministries in Kenya
(strategic Journals, 2015-10-16) Gitonga, L.; Gachunga, H.
Work environment has both positive and negative effects on the psychological and welfare of employees. The Kenyan government acknowledges that over the years there has been poor performance in the public sector, thus hindering service delivery which affect the realization of sustainable economic growth. The general objective of the study was to establish the influence of work environment on organizational performance in government ministries in Kenya. The target population was drawn from 6 government ministries based on the performance contracting reports of 2012. The total population was 7913 and the sample size was 367 according to (Krecie and morgan 1970) table. Stratified random sampling technique was employed in selecting the sample. The study adopted descriptive research design and primary data was collected using a questionnaire in the selected government ministries. A pilot study was done to test the validity and reliability of the instrument for data collection. Data was analysed by SPSS version 21. The study employed quantitative analysis techniques and correlated and generated findings showing that the variables were significantly and positively influenced organizational performance in government ministries in Kenya. Psychosocial environment was the most significant factor and had a positive significant relationship at 5% level of significance. The study recommends that there is need to ensure effective policies to enhance organizational performance in government ministries in Kenya as established in the study.
Interaction between Phaedrotoma scabriventris Nixon and Opius dissitus Muesebeck (Hymenoptera: Braconidae): endoparasitoids of Liriomyza leafminer
(African Entomology, 2015) Foba, C.N; Langat, Z.O.; Gitonga, L.M.; Akutse, K.S.; Fiaboe, K.K.M.
The exotic parasitoid, Phaedrotoma scabriventris Nixon, was imported from Peru for the biological control of invasive Liriomyza species in vegetable and ornamental crops in Kenya where Opius dissitus Muesebeck is the most abundant indigenous Liriomyza parasitoid. Both species are solitary larva-pupal endoparasioids attacking the same larval stage. In order to assess whether these two species compete or co-exist, an interaction study involving sole, sequential and simultaneous releases of the two species on polyphagous Liriomyza huidobrensis (Blanchard) was conducted in the laboratory at the International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya. Simultaneous releases of 50 individuals each of the two parasitoids resulted in significantly higher total parasitism rate (61.96 ± 4.60) than in the single release of P. scabriventris (34.94 ± 8.50). Simultaneous release of 25 individuals of each species resulted in a parasitism rate (44.52 ± 2.75) similar to that obtained for single releases of 50 individuals of O. dissitus (42.57 ± 3.35) and P. scabriventris (34.94 ± 8.50). No significant effect was observed in total parasitism between sequential and single releases of 50 individuals of each species. The specific parasitism rate of each parasitoid species in the simultaneous release of 50 individuals of each species was not significantly different from when each species was released alone. The first introduced parasitoid in sequential releases achieved the same parasitism rate as when released alone. However, the second released species gave a significantly lower parasitism rate than when released alone and compared to the first released species. The F1 progeny sex ratio was balanced for P. scabriventris but male-biased in O. dissitus. The sex ratios of both parasitoid species were not significantly affected, neither in simultaneous nor sequential releases, except in one of the sequential release where P. scabriventris was released second, with its sex ratio significantly female-biased. Non-reproductive host mortality was not important for both parasitoids when used alone and in combined releases compared to the natural mortality observed in the control. These findings suggest that P. scabriventris has no detrimental effect on O. dissitus and its release into Kenya’s agricultural ecosystems will enhance the management of Liriomyza leafminer.
Interaction between Phaedrotomascabriventris Nixon and Opiusdissitus Muesebeck (Hymenoptera: Braconidae) : endoparasitoids of Liriomyza leafminer
(Sabinet African Journals, 2015-03-01) Foba, C.N.; Akutse, K.S.; Fiaboe, K.K.M.; Lagat, Z.O.; Gitonga, L.M.
The exotic parasitoid, Phaedrotoma scabriventris Nixon, was imported from Peru for the biological control of invasive Liriomyza species in vegetable and ornamental crops in Kenya where Opius dissitus Muesebeck is the most abundant indigenous Liriomyza parasitoid. Both species are solitary larva-pupal endoparasioids attacking the same larval stage. In order to assess whether these two species compete or co-exist, an interaction study involving sole, sequential and simultaneous releases of the two species on polyphagous Liriomyza huidobrensis (Blanchard) was conducted in the laboratory at the International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya. Simultaneous releases of 50 individuals each of the two parasitoids resulted in significantly higher total parasitism rate (61.96 ± 4.60) than in the single release of P. scabriventris (34.94 ± 8.50). Simultaneous release of 25 individuals of each species resulted in a parasitism rate (44.52 ± 2.75) similar to that obtained for single releases of 50 individuals of O. dissitus (42.57 ± 3.35) and P. scabriventris (34.94 ± 8.50). No significant effect was observed in total parasitism between sequential and single releases of 50 individuals of each species. The specific parasitism rate of each parasitoid species in the simultaneous release of 50 individuals of each species was not significantly different from when each species was released alone. The first introduced parasitoid in sequential releases achieved the same parasitism rate as when released alone. However, the second released species gave a significantly lower parasitism rate than when released alone and compared to the first released species. The F1 progeny sex ratio was balanced for P. scabriventris but male-biased in O. dissitus. The sex ratios of both parasitoid species were not significantly affected, neither in simultaneous nor sequential releases, except in one of the sequential release where P. scabriventris was released second, with its sex ratio significantly female-biased. Non-reproductive host mortality was not important for both parasitoids when used alone and in combined releases compared to the natural mortality observed in the control. These findings suggest that P. scabriventris has no detrimental effect on O. dissitus and its release into Kenya's agricultural ecosystems will enhance the management of Liriomyza leafminer.
Knowledge Levels of Breast Cancer Among Women of Reproductive Age in Kenya, a Case Study of Kitui County
(Central African Journal of Public Health, 2020) Koech, Cheruiyot Fred; Nzioki, Mativo; Karama, Mohammed; Muinde, Fridah Ndinda
Background: Breast cancer is one of the leading causes of mortality among women in the world today. Therefore there is need for concerted efforts to advance interventions that seek to mitigate challenges associated with its screening. In Kenya, breast cancer accounts for 23% of cancerous diseases that affect women. The purpose of this study was to determine the knowledge levels on breast cancer among women of reproductive age in Kitui County, roll out community based health education intervention (CBHI) targeted at enhancing breast cancer knowledge, and finally to assess the effect of the CBHI on knowledge levels. Methods: The study design adopted was quasi-experimental. This was adopted because it enables researchers to evaluate causal relationships when interventions or agents of causation are induced. This study was undertaken with the causal mechanism being the rollout of CBHI and the impact in knowledge of breast cancer. Two groups were evaluated; intervention and control groups. The knowledge among these groups was evaluated between two time intervals; end line and at baseline. Data was collected using questionnaire instruments, analyzed using SPSS v23 and presented in form of tables and frequencies. Inferential analysis was achieved through binary logistic regression and Difference in Difference scores. Results: The individual score analysis on different aspect of breast cancer knowledge and awareness indicated that there was a direct positive impact of the CBHI on the knowledge on breast cancer among the respondents. Significant changes observed upon the implementation of CBHI on breast cancer included; respondents in the intervention group who knew at least two danger signs for breast cancer increased to 3.8 (Adj. OR=3.895, P<0.05, 95%CI: 2.538-5.979), those who knew the age related risks associated with breast cancer increased by 4.1 (Adj. OR=4.128, P<0.05, 95%CI: 2.940-5.797), and finally, those who knew at least one Breast cancer screening method increased 7 fold among the intervention group after the rollout of CBHI (Adj. OR=7.011, P<0.05, 95%CI: 4.138-11.880). Conclusion: The impact of CBHI on knowledge of breast cancer was significant. As a result, more people in the intervention group were cognizant of different warning signs of breast cancer, breast cancer screening methods, and that these opportunities facilitate early detection of breast cancer. The actionable strategies recommended by this study is implementation of community based strategies to enhance knowledge levels on breast cancer in order to improve screening uptake and therefore early detection of breast cancer.
Liriomyza Leafminer (Diptera: Agromyzidae) Parasitoid Complex in Different Agroecological Zones, Seasons, and Host Plants in Kenya
(Environmental Entomology, 2015) Gitonga, L. M.; Foba, C. N.; Salifu, D.; Lagat, Z. O.; Akutse, K. S.; Fiaboe, K. K. M.
Liriomyza leafminers (Diptera: Agromyzidae) are severe pests of vegetables and ornamentals worldwide. Previous studies revealed low leafminer parasitism across different agroecological zones in Kenya. The present paper reports on the composition of leafminer parasitoids at different elevations, in different seasons, and on different host crops. Surveys were conducted monthly from January to November 2012, and nine parasitoid species were recovered. Total mean parasitism in the study sites was 31.23 6 1.03% from a total of 20 different vegetable Liriomyza-infested crops belonging to seven families. Diglyphus isaea (Walker) (Hymenoptera: Eulophidae), Phaedrotoma scabriventris, a newly released parasitoid, and Opius dissitus Muesebeck (Hymenoptera: Braconidae) were the most abundant at all elevations, accounting for 67.3, 18.6, and 9.2% of total parasitoids, respectively. Elevation, season, and host crop significantly affected the parasitoid species present and their abundance. Diglyphus isaea was more abundant at the high- and mid-elevations at all seasons compared with the low-elevation, whereas the lower-elevation favored higher abundance of P. scabriventris and O. dissitus during the long rainy season compared with the high- and mid-elevations at all seasons. Of all the host crops surveyed, parasitoids were more abundant on tomato, local kidney bean, snow pea and French bean than other crops. The total parasitism rate observed in this study suggests a considerable improvement in leafminer parasitism compared with previous surveys in Kenya. The implications of these findings for leafminer management in vegetable and ornamental production in Kenya are discussed
The monotypic genus Bulborrhizina belongs to Bulbothrix sensu lato (Parmeliaceae, Ascomycota)
(The American Bryological and Lichenological Society, Inc. - The Bryologist, 2015) Kirika, Paul, M.; Leavitt, Steven, D.; Divakar, Pradeep, K.; Crespo, Ana; Gatheri, Grace; Mugambi, George; Lumbsch, Thorsten, H.
The phylogenetic position of the monotypic genus Bulborrhizina is studied using molecular data from three loci (mtSSU, nuLSU and ITS) aligned with sequences from 95 other samples of parmelioid lichens. Bulborrhizina africana clusters within the predominantly paleotropical Bulbothrix ‘clade II’ with strong support. However, its relationships within this clade remain uncertain. The morphological characters used to circumscribe Bulborrhizina are interpreted as adaptations to the habitat of this species in semi-arid regions of eastern Africa. A formal synonymy of the genus Bulborrhizina with either Bulbothrix or Parmelinella is postponed until sequences of the type species of Bulbothrix become available that will allow us to identify which of the two clades of species currently placed in Bulbothrix represents Bulbothrix s.str.