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The expression of Spodoptera exigua P450 and UGT genes: tissue specificity and response to insecticides

Insect Science 2019年第2期26卷 199-216页

作者： Bo Hu Shu-Heng Zhang Miao-Miao Ren Xiang-Rui Tian Qi Wei david Kibe mburu Jian-Ya Su Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education) College of Plant Protection Nanjing Agricultural University Nanjing China

Cytochrome P450 and UDP-glucosyltransferase (UGT) as phase I and phase II metabolism enzymes, respectively, play vital roles in the breakdown of endobiotics and xenobiotics. Insects can in crease the expression of detoxificatio n enzymes to cope with the stress from xenobiotics including insecticides. However, the molecular mechanisms for insecticide detoxification in Spodoptera exigua remain elusive, and the genes conferring insecticide metabolisms in this species are less well reported. In this study, 68 P450 and 32 UGT genes were identified. Phylogenetic analysis showed gene expansions in CYP3 and CYP4 clans of P450 genes and UGT33 family of this pest. P450 and UGT genes exhibited specific tissue expression patterns. Insecticide treatments in fat body cells of S. exigua revealed that the expression levels of P450 and UGT genes were significantly influenced by challenges of abamectin, lambda-cyhalothrin, chlorantraniliprole, metaflumizone and indoxacarb. Multiple genes for detoxification were affected in expression levels after insecticide exposures. The results demonstrated that lambda-cyhalothrin, chlorantraniliprole, metaflumizone and indoxacarb induced similar responses in the expression of P450 and UGT genes in fat body cells;eight P450 genes and four UGT genes were co-up-regulated significantly, and no or only a few CYP/UGT genes were down-regulated significantly by these four insecticides. However, abamectin triggered a distinct response for P450 and UGT gene expression;more P450 and UGT genes were down-regulated by abamectin than by the other four compounds. In con elusion, P450 and UGT genes from S. exigua were identified, and different responses to abamectin suggest a different mechanism for insecticide detoxification.

关键词： abamectin cytochrome P450 monooxygenases gene expression insecticide Spodoptera exigua UDP-glycosyltransferase

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Short Term Leguminous Trees-Tillage Interactions and Their Effect on Soil-Water Content in a Semi-Arid Agroforestry Parkland

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Open Journal of Forestry 2015年第7期5卷 668-677页

作者： Chester Kalinda david mburu Kamau Ngamau Lwali A. Chisala Donald Zulu John Kihoro Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya The Copperbelt University Kitwe Zambia

Agricultural activities that encourage slashing, burning and ploughing greatly affect the soil structure and soil organic matter on which soil water retention depends. In this study, we hypothesized that inclusion of rotational leguminous tree species improves soil water retention in a semi-arid conservation agriculture system. In a study done in Kibwezi, semi-arid eastern Kenya, results showed that the amount of water retained in the different soil strata from plots with different tree species and tillage practices was highly significant (P = 0.032). Plots with planting basins and Gliricidia sepium and Faidherbia albida tree species retained more water in both the upper and lower strata. Plots with G. sepium tree species under planting basins and zero tillage under F. albida had significantly higher soil organic carbon levels than plots that were managed under ridges and ploughing (P = 0.002). On the other hand, bulk density in plots with planting basins and zero tillage and ridges ranged between 1.35 g/cm3 and 1.53 g/cm3. Conventional tillage plots had bulk density values of 1.65 g/cm3 and 1.72 g/cm3 in the upper and lower strata respectively. The time-dependent nature of rotational leguminous tree species on soil organic matter and soil water retention in the semi-arid conservation agriculture system highlights the importance of considering these species for improving organic carbon and water retention for improved crop production.

关键词： G. sepium F. albida T. candida Leguminous Tree Species Soil Organic Carbon Soil Water Retention Infiltration

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Assessment of the Impact of Environment Protection in Rwanda:A Case Study of Rugezi Marshland

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NASS Journal of Agricultural Sciences 2022年第1期4卷 49-55页

作者： Ntabakirabose Gaspard Harold Ogwal Jean Baptiste Habinshuti Musoni Protais Jeanne Pauline Munganyinka david Mwehia mburu Maniriho Festus Ministry of Agriculture and Animal Resources KigaliRwanda Department of Biological and Environmental Sciences School of Natural and Applied SciencesKampala International UniversityKampalaUganda Department of Materials Science and Engineering African University of Science and TechnologyAbujaNigeria Musanze District Ministry of Local GovernmentKigaliRwanda Department of Land Resources Planning and Management College of Agriculture&Natural ResourcesJomo Kenyatta University of Agriculture and Technology(JKUAT) NairobiKenya 6.College of AgricultureAnimal Sciences and Veterinary Medicine(UR-CAVM)University of RwandaKigaliRwanda

Environmental protection is one of the most important measures to achieve the long run and sustainability of living organisms in the *** study was conducted in Burera and Gicumbi districts with the main aim of assessing the impact of environment protection in Rwanda.A case study of Rugezi *** were collected using a structured questionnaire and analyzed using SPSS statistical software version 20 and STATA statistical software vision ***-farm income,occupation,educational level,age,and farm size,showed a positive relationship with Rugezi marchland *** such as value of product distance to Rugezi marchland,gender,and family size had a negative influence on Rugezi marchland *** study also indicated that factors such as water management,increase of grass species,increase of wild animals and birds,modern house construction,zero grazing keeping revealing a positive relationship with Rugezi marchland *** most serious problems encountered are the lack of occupation and low level of education.

关键词： Assessment Impact Environment protection Rugezi Marshland

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Long-term changes in the plant ecology of an African savanna landscape and the implications for ecosystem theory and conservation management

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Ecological Processes 2021年第1期10卷 213-224页

作者： david Western Victor N.Mose david Maitumo Caroline mburu African Conservation Centre P.O.Box 15289-00509NairobiKeny

Background:Studies of the African savannas have used national parks to test ecological theories of natural ecosystems,including equilibrium,non-equilibrium,complex adaptive systems,and the role of top-down and bottom-up physical and biotic *** such studies have excluded the impact of pastoralists in shaping grassland ecosystems and,over the last half century,the growing human impact on the world’s *** mounting human impact calls for selecting indicators and integrated monitoring methods able to track ecosystem changes and the role of natural and human *** study draws on five decades of monitoring the Amboseli landscape in southern Kenya to document the declining role of natural agencies in shaping plant ecology with rising human ***:We show that plant diversity and productivity have declined,biomass turnover has increased in response to a downsizing of mean plant size,and that ecological resilience has declined with the rising probability of extreme shortfalls in pasture *** signature of rainfall and physical agencies in driving ecosystem properties has decreased sharply with growing human *** compare the Amboseli findings to the long-term studies of Kruger and Serengeti national parks to show that the human influence,whether by design or default,is increasingly shaping the ecology of savanna *** look at the findings in the larger perspective of human impact on African grasslands and the world rangelands,in general,and discuss the implications for ecosystem theory and conservation policy and ***:The Amboseli study shows the value of using long-term integrated ecological monitoring to track the spatial and temporal changes in the species composition,structure,and function of rangeland ecosystems and the role of natural and human agencies in the process of *** study echoes the widespread changes underway across African savannas and world’s rangelands,concluding that some level

关键词： Savannas Plants Human dominance Macroecology Conservation

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Preference and adoption of Farmer Field School (FFS) Prosopis juliflora management practices: Experiences in Baringo District, Kenya

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Forestry Studies in China 2012年第4期14卷 283-290页

作者： Eunice NJOROGE Peter SIRMAH Francis mburu Eric KOECH Mugo MWARE Josiah CHEPKWONY School of Natural Resource Management Moi University School of Natural Resource Management Kabianga University

This research was carried out to evaluate the preference and adoption of harvesting, uprooting, stump burning, pruning and thinning practices for controlling the spread ofProsopisjuliflora （prosopis） within Marigat Division of the Baringo District, Kenya. A survey methodology was employed using a random sample of 25 Farmer Field School （FFS） members and 5 non=FFS members from each of the five locations of Marigat Division. In total, 100 FFS members and 25 non-FFS members participated in the study; addi- tional supplementary data were collected from the Kenya Forestry Research Institute （KEFRI）, a major facilitator and trainer of the identified FFS activities and practices in the study area since 2004. More than 80% of the local community never undertook any form of prosopis management practice; however, this changed after FFS training, indicating an acquisition and retention of knowledge which probably diffused to the non-FFS counterparts, through either formal or informal ways. Harvesting was the most preferred （100%） and stump burning the least preferred （46%） practice of managing the spread of prosopis. The success and preference of any prosopis management practice was attributed to wood and non-wood benefits derived from prosopis and growing of animal fodder and food crops on rehabilitated land. More than 80% of respondents attributed ineffectiveness of any prosopis management practice to coppicing and viable seed banks of the tree, while 50% highlighted a lack of consistency and integration in carrying out manage- ment practices. The reported negative attitude towards prosopis changed after training with none of the view to eradicate it. Labor intensity and frequent regeneration of seedlings were identified as the major challenges faced during the implementation of proso- pis management practices. In conclusion, the study shows that harvesting, uprooting, stump burning, pruning and thinning realized through consistent holistic integration contribute to containi

关键词： Prosopisjuliflora Farmer Field School management practices Baringo Kenya

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Effects of Post Eviction Resettlement on Land-Use and Cover Change in Uganda’s Oil Exploration Areas

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Journal of Environmental Protection 2017年第10期8卷 1144-1157页

作者： Joseph Ssekandi John mburu Oliver Wasonga Laban Macopiyo Francis Charles Department of Land Resource Management and Agricultural Technology University of Nairobi P.O. Nairobi Kenya Department of Plant Sciences [IPV] Norwegian Univ. Life Sciences &Aring s Norway Department of Agronomy & Horticulture Plant Science Univ. Nebraska Lincoln NE USA

Evaluation of the changes in land use and land cover change (LULCC) in respect to oil exploration across the Albertine region in Uganda has been focused around the exploration areas and protected areas, with no attention to the potential impacts of evictees’ activities on resettled areas. This study used LANDSAT images to analyze the land use and land cover changes (LULCC) among the period before eviction (2002 and 2005) at the climax of eviction and resettlements (2005-2011), and during the post-resettlement period (2011-2015) to quantify the impacts of resettlements on the environment. LANDSAT images were processed using ERDAS IMAGINE software and analyzed using ArcGIS 10.1 to determine LULCC in relation to post-eviction resettlement in the study area. Results from the study indicate. The results of the study indicate that vegetation reduced by 33.08 percent, woodland were converted into settlements by 48 percent while farmlands increased by 18.3 percent. Non vegetated areas increased during resettlements however they reduced five years after eviction which indicated the ability of the ecosystem to stabilize. The study proved that post eviction induced resettlements can yield potential environmental effects to resettled areas. It is important therefore to plan and implement other means of additional source of income and construction materials for evictees to abate vegetation clearance and hence rescue the woodland. The study also recommends maintenance of an optimum population and well-planned pre eviction resettlement schemes.

关键词： Land Use Land Cover Resettlement Woodlands Evictions

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An Assessment of Barriers to MSMEs’ Adoption of CSA in Livestock Red Meat Value Chain, Kajiado County, Kenya

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American Journal of Climate Change 2021年第3期10卷 237-262页

作者： Mary Waceke Thongoh Henry Mikiugu Mutembei John mburu Bessy Eva Kathambi Wangari Maathai Institute for Peace and Environmental Studies (WMI) University of Nairobi Nairobi Kenya Department of Clinical Studies University of Nairobi Nairobi Kenya Department of Agricultural Economics University of Nairobi Nairobi Kenya

Climate change poses great risks to poverty alleviation, food security and livelihoods sustainability in sub-Saharan Africa, declining crop yields and livestock productivity, especially in ASALs that suffer from fragile ecosystems characterized by frequent droughts and low rainfall. Climate-Smart Agriculture (CSA) objectives of improving productivity and incomes, adaptation, resilience to climate change and mitigation on GHGs emissions, are responses to these climate risks. CSA technologies, innovation and management practices (TIMPs) in general do exist, however they are concentrated in crop farming neglecting livestock production and especially in marginalized areas such as ASALs, which forms 85% of Kenyan land mass and is dominated by pastoral and nomadic livestock production. Most CSA practices are mainly at the production level and hardly extend to the entire value chain, and diffusion is slow due to several barriers. A mixed method approach was used to evaluate barriers to actors’ adoption of CSA in the pastoral Livestock red meat value chain starting from input suppliers, producers, to consumers (pasture to plate). This study used six broad perspectives to examine the barriers: 1) Knowledge and institutional;2) Market and financial;3) Policy and incentives;4) Networks and engagement platforms;5) Cultural and social;6) Physical infrastructure barriers. These barriers can be surmounted with concerted efforts from the government, development partners, pastoral communities, value chain actors and public private partnership among others. Efforts such as modernization of the pastoral red meat value chains, integration of MSMEs into the livestock systems, access to affordable financing, availability of context based, affordable CSA TIMPs, incentives, policies and institutional support, which currently remains inadequate. Institutional barriers like lack of capacity, coupled with knowledge and behavioral barriers hinder adoption. Financial institutions and cooperativ

关键词： Barriers Climate-Smart Livestock CSA TIMPs Enablers Incentives Policies Red Meat Value Chain

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Physical, Total Phenolic and Total Flavonoid Properties of Chia (Salvia hispanica L.) Seeds Grown in Kenya

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Food and Nutrition Sciences 2022年第12期13卷 973-985页

作者： Pauline W. Ikumi Monica mburu Daniel Njoroge Nicholas Gikonyo Benjamin Musyimi Musingi Institute of Food and Bioresources Technology Dedan Kimathi University of Technology Nyeri Kenya National Phytotherapeutics Research Centre Kenyatta University Nairobi Kenya Animal Breeding and Genomics Group Department of Animal Sciences Egerton University Egerton Kenya Department of Biological Sciences Egerton University Egerton Kenya

In the recent past, there has been an increased uptake of chia seeds (Salvia hispanica L.) by consumers resulting in the increased adoption of chia farming, particularly in Kenya whereby most farmers are practising subsistence farming and a few farming it commercially. The widespread farming of chia seeds in Kenya translates to increased uptake at household level while offering a niche for industrial processing of chia seeds necessitating the need for studies on physical, total phenolic and flavonoid properties of chia seeds grown in Kenya. The physical, total phenolic and flavonoid properties of chia seeds from two chia planning seasons April to August 2019 and September to December 2019 were evaluated. The physical attributes (length, width and thickness) were determined using a digital vernier calliper while proximate components were determined using AOAC standard methods. The Quencher procedure was used to determine the total phenolic and flavonoid contents. Chia seeds revealed a length of 1.82 to 2.32 (mm), a width of 1.15 to 1.31 (mm) and a thickness of 0.77 to 0.88 (mm). The percentage moisture content of chia seeds was 7.23 to 10.67, percentage of crude fat was 31.48 to 42.45, percentage of crude ash was 3.63 to 6.82, and percentage of crude fibre was 30.95 to 38.65 and percentage of crude protein was17.82 to 28.97. The total phenolic content observed for chia seeds was 0.73 to 0.87 mg GAE g-1 while total flavonoid content was 0.39 to 0.57 mg GAE g-1. The proximate components of chia seeds varied significantly (p < 0.05) based on the chia planting season while the physical properties, total phenolics and total flavonoid contents did not vary significantly.

关键词： Chia (Salvia hispanica L.) Seeds Properties

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Suitability of Green Gram Production in Kenya under Present and Future Climate Scenarios Using Bias-Corrected Cordex RCA4 Models

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Agricultural Sciences 2020年第10期11卷 882-896页

作者： Jane Wangui Mugo Franklin J. Opijah Joshua Ngaina Faith Karanja Mary mburu Department of Meteorology South Eastern Kenya University Kwa Vonza Kenya Department of Meteorology University of Nairobi Nairobi Kenya Department of Geospatial and Space Technology University of Nairobi Nairobi Kenya Department of Agriculture and Veterinary Sciences South Eastern Kenya University Kwa Vonza Kenya

Green gram is considered as one of the legumes suitable for cultivation in the Arid and Semi-Arid Lands (ASALs) of Kenya. However, climate change may alter the areas suitable for green gram production. This study sought to model green gram suitability in Kenya under present and future conditions using bias-corrected RCA4 models data. The datasets used were: maps of soil parameters extracted from Kenya Soil Survey map;present and future rainfall and temperature data from an ensemble of nine models from the Fourth Edition of the Rossby Centre (RCA4) Regional Climate Model (RCM);and altitude from the Digital elevation model (DEM) of the USGS. The maps were first reclassified into four classes of suitability as Highly Suitable (S1), Moderately Suitable (S2), Marginally Suitable (S3), and Not Suitable (N). The classes represent the different levels of influence of a factor on the growth and yield of green grams. The reclassified maps were then assigned a weight generated using the Analytical Hierarchy Process (AHP). A weighted overlay of climate characteristics (past and future rainfall and temperature), soil properties (depth, pH, texture, CEC, and drainage) and altitude found most of Kenya as moderately suitable for green gram production during the March to May (MAM) and October to December (OND) seasons under the baseline, RCP 4.5 and RCP 8.5 scenarios with highly suitable areas being found in Counties like Kitui, Makueni, and West Pokot among others. During the MAM season, the area currently highly suitable for green gram production (67,842.62 km2) will increase slightly to 68,600.4 km2 (1.1%) during the RCP 4.5 and reduce to 61,307.8 km2 (−9.6%) under the RCP 8.5 scenario. During the OND season, the area currently highly suitable (49,633.4 km2) will increase under both RCP 4.5 (22.2%) and RCP 8.5 (58.5%) scenarios. This increase is as a result of favourable rainfall and temper

关键词： Climate Change Green Gram Kenya Rainfall Soil Suitability Temperature Topography

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Rainfall Variability under Present and Future Climate Scenarios Using the Rossby Center Bias-Corrected Regional Climate Model

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American Journal of Climate Change 2020年第3期9卷 243-265页

This study sought to determine the spatial and temporal variability of rainfall under past and future climate scenarios. The data used comprised station-based monthly gridded rainfall data sourced from the Climate Research Unit (CRU) and monthly model outputs from the Fourth Edition of the Rossby Centre (RCA4) Regional Climate Model (RCM), which has scaled-down nine GCMs for Africa. Although the 9 Global Climate Models (GCMs) downscaled by the RCA4 model was not very good at simulating rainfall in Kenya, the ensemble of the 9 models performed better and could be used for further studies. The ensemble of the models was thus bias-corrected using the scaling method to reduce the error;lower values of bias and Normalized Root Mean Square Error (NRMSE) were recorded when compared to the uncorrected models. The bias-corrected ensemble was used to study the spatial and temporal behaviour of rainfall under baseline (1971 to 2000) and future RCP 4.5 and 8.5 scenarios (2021 to 2050). An insignificant trend was noted under the baseline condition during the March-May (MAM) and October-December (OND) rainfall seasons. A positive significant trend at 5% level was noted under RCP 4.5 and 8.5 scenarios in some stations during both MAM and OND seasons. The increase in rainfall was attributed to global warming due to increased anthropogenic emissions of greenhouse gases. Results on the spatial variability of rainfall indicate the spatial extent of rainfall will increase under both RCP 4.5 and RCP 8.5 scenario when compared to the baseline;the increase is higher under the RCP 8.5 sce

关键词： CORDEX Climate Change Bias Correction Ensemble Rainfall Kenya RCA4

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