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Full-Text Articles in Life Sciences

Identification Of Insect-Selective And Mammal-Selective Toxins From Parabuthus Leiosoma Venom, John B. Ochola, Wilber Lwande, Thuku Thiong'o, Lucie Rogo, Rafael Herrmann, Eric Schepers, Richard Bagine, Paul Mungai, Isaiah O. Ndiege Sep 2007

Identification Of Insect-Selective And Mammal-Selective Toxins From Parabuthus Leiosoma Venom, John B. Ochola, Wilber Lwande, Thuku Thiong'o, Lucie Rogo, Rafael Herrmann, Eric Schepers, Richard Bagine, Paul Mungai, Isaiah O. Ndiege

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Venoms were collected from two scorpion species: Parabuthus leiosoma and Parabuthus pallidus from Kenya. Subcutaneous injection and oral toxicity tests of crude and pure fractions of scorpion venoms were done in Mus musculus (mice), Chilo partellus and Busseola fusca. The highest activity against C. partellus was found in P. leiosoma venom (LC50 0.689 mg/50 mg body weight). Bioassay-guided purification by a combination of cation-exchange (CE) and reverse-phase high-performance liquid chromatography (RP-HPLC) led to the isolation of three toxic peptides. A lepidopteran-selective toxin (P. leiosoma insect toxin, Plit) was isolated, and the partial N-terminal amino acid sequence (-KDGYPVDNANCKYE-) plus the molecular …

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Inheritance Of 'Domestication' Traits In Bambara Groundnut (Vigna Subterranea (L.) Verdc.), Shravani Basu, Sean Mayes, Michael Davey, Jeremy A. Roberts, Sayed N. Azam-Ali, Richard Mithen, Remy S. Pasquet Sep 2007

Inheritance Of 'Domestication' Traits In Bambara Groundnut (Vigna Subterranea (L.) Verdc.), Shravani Basu, Sean Mayes, Michael Davey, Jeremy A. Roberts, Sayed N. Azam-Ali, Richard Mithen, Remy S. Pasquet

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Controlled crosses in bambara groundnut were attempted between a range of thirty-six bambara groundnut landraces (thirty domesticated (V. subterranea var. subterranea) and six wild (V. subterranea var. spontanea)). Ten F1 seed were produced. Of these, eight germinated producing F2 populations. On seed set, four populations could be unambiguously confirmed as true crosses by F3 seed coat colour. A single F2 population, derived from a domesticated landrace from Botswana (DipC; female parent) crossed with a wild accession collected in Cameroon (VSSP11; male parent) was used to study a range of agronomic and domestication traits. These included; days to emergence, days to …

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Impact Of An Exotic Parasitoid On Plutella Xylostella (Lepidoptera: Plutellidae) Population Dynamics, Damage And Indigenous Natural Enemies In Kenya, B. Löhr, R. Gathu, C. Kariuki, J. Obiero, G. Gichini Aug 2007

Impact Of An Exotic Parasitoid On Plutella Xylostella (Lepidoptera: Plutellidae) Population Dynamics, Damage And Indigenous Natural Enemies In Kenya, B. Löhr, R. Gathu, C. Kariuki, J. Obiero, G. Gichini

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Diadegma semiclausum (Hellén) (Hymenoptera: lchneumonidae), an exotic diamondback moth parasitoid, was released in two pilot areas (Werugha in Coast Region and Tharuni in Central Province) in Kenya. Fifteen month before release, observations on the diamondback moth, Plutella xylostella (Linnaeus), and local natural enemy population dynamics and pest damage were initiated in both areas and continued for three years after release. The P. xylostella population was bimodal with higher records during dry seasons. At Werugha, the peak population of P. xylostella was 16.8 per plant (October 2001); at Tharuni it was 12.8 (February 2002). Populations at Werugha declined from three months …

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Composition Of Volatiles From Fermenting Pollen Dough And Attractiveness To The Small Hive Beetle Aethina Tumida, A Parasite Of The Honeybee Apis Mellifera, Baldwyn Torto, Richard T. Arbogast, Hans Alborn, Alonso Suazo, Dennis Van Engelsdorp, Drion Boucias, James H. Tumlinson, Peter E.A. Teal Jul 2007

Composition Of Volatiles From Fermenting Pollen Dough And Attractiveness To The Small Hive Beetle Aethina Tumida, A Parasite Of The Honeybee Apis Mellifera, Baldwyn Torto, Richard T. Arbogast, Hans Alborn, Alonso Suazo, Dennis Van Engelsdorp, Drion Boucias, James H. Tumlinson, Peter E.A. Teal

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The response of the small hive beetle (SHB), Aethina tumida Murray, to volatiles from a pollen-based diet conditioned by the feeding of 100 adult virgin female or male SHBs (4-8 weeks old) for 1, 3, 7 or 14 days is described and compared to that of the same diet inoculated with the yeast Kodamaea ohmeri (NRRL Y-30722), isolated from the beetle. In a wind tunnel, volatiles from pollen dough conditioned by beetles of either sex for 3 or 7 days lured significantly more beetles into traps than volatiles from unconditioned dough. In contrast, trap captures with volatiles from dough conditioned …

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Differential Expression Of The Crv1 Haemocyte Inactivation-Associated Polydnavirus Gene In The African Maize Stem Borer Busseola Fusca (Fuller) Parasitized By Two Biotypes Of The Endoparasitoid Cotesia Sesamiae (Cameron), C. W. Gitau, D. Gundersen-Rindal, M. Pedroni, P. J. Mbugi, S. Dupas Jul 2007

Differential Expression Of The Crv1 Haemocyte Inactivation-Associated Polydnavirus Gene In The African Maize Stem Borer Busseola Fusca (Fuller) Parasitized By Two Biotypes Of The Endoparasitoid Cotesia Sesamiae (Cameron), C. W. Gitau, D. Gundersen-Rindal, M. Pedroni, P. J. Mbugi, S. Dupas

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Polydnaviruses are rarely studied for their natural variation in immune suppressive abilities. The polydnavirus harboring braconid Cotesia sesamiae, a widespread endoparasitoid of Busseola fusca and Sesamia calamistis in sub-Saharan Africa exists as two biotypes. In Kenya, the western biotype completes development in B. fusca larvae. However, eggs of the coastal C. sesamiae are encapsulated in this host and ultimately, no parasitoids emerge from parasitized B. fusca larvae. Both biotypes develop successfully in S. calamistis larvae. Encapsulation activity by B. fusca larvae towards eggs of the avirulent C. sesamiae was detectable six hours post-parasitization. The differences in encapsulation of virulent and …

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Cross-Modality Effects During Male-Male Interactions Of Jumping Spiders, Fiona R. Cross, Robert R. Jackson, Simon D. Pollard, Mark W. Walker Jul 2007

Cross-Modality Effects During Male-Male Interactions Of Jumping Spiders, Fiona R. Cross, Robert R. Jackson, Simon D. Pollard, Mark W. Walker

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An important prediction from game theory is that the value of a resource influences the level to which male-male conflict escalates. Earlier experimental studies have shown that the seven salticid species we study here (Bavia aericeps, Euryattus sp., Hypoblemum albovittatum, Jacksonoides queenslandicus, Marpissa marina, Portia africana and Simaetha paetula) determine by sight whether a female is a conspecific or a heterospecific and then escalate the intensity with which they interact (i.e., they adopt behaviour that is likely to put them at greater risk of injury after detecting the presence of a conspecific female). Here the earlier studies are extended by …

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Livestock Farmers' Perception And Epidemiology Of Bovine Trypanosomosis In Kwale District, Kenya, S. O. Ohaga, E. D. Kokwaro, I. O. Ndiege, A. Hassanali, R. K. Saini Jun 2007

Livestock Farmers' Perception And Epidemiology Of Bovine Trypanosomosis In Kwale District, Kenya, S. O. Ohaga, E. D. Kokwaro, I. O. Ndiege, A. Hassanali, R. K. Saini

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We did cross-sectional surveys in Kwale District, Kenya to determine the epidemiology of bovine trypanosomosis and livestock owners' perceptions of the disease. The surveys involved relative importance of trypanosomosis, examination of the current disease constraints, current control practices and drug-use patterns. Informal meetings were held with farmers and cattle census undertaken. Tsetse-fly densities and trypanosomosis prevalences in cattle were determined. A total of 132 farmers were interviewed. Trypanosomosis, anaplasmosis, East Coast fever, foot-and-mouth diseases were reported to be the major constraints to livestock production. Trypanosomosis was the most important compared to other diseases. Chemotherapy was the most widely used method …

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Plant Growth-Promoting Rhizobacteria Do Not Pose Any Deleterious Effect On Cowpea And Detectable Amounts Of Ethylene Are Produced, Olubukola O. Babalola, Abiodun I. Sanni, George D. Odhiambo, Baldwyn Torto Jun 2007

Plant Growth-Promoting Rhizobacteria Do Not Pose Any Deleterious Effect On Cowpea And Detectable Amounts Of Ethylene Are Produced, Olubukola O. Babalola, Abiodun I. Sanni, George D. Odhiambo, Baldwyn Torto

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The use of trap crops such as cowpea could reduce the effects of the root parasitic weed, Striga hermonthica and its subsequent constraints on the growth of cereals. Certain bacteria could augment the trap crop stimulatory effect. We studied the effect of three bacteria introduced to the rhizosphere of three cowpea varieties at planting. Number of days to cowpea flowering was noted and at harvest, data were collected on pod characteristics and biomass. Means of data subjected to ANOVA were compared using Tukey's Studentized Range Test. We analysed bacterial headspace volatiles for ethylene by gas chromatography and gas chromatography-mass spectrometry. …

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Larval Habitats Of Anopheles Gambiae S.S. (Diptera: Culicidae) Influences Vector Competence To Plasmodium Falciparum Parasites, Bernard A. Okech, Louis C. Gouagna, Guiyun Yan, John I. Githure, John C. Beier May 2007

Larval Habitats Of Anopheles Gambiae S.S. (Diptera: Culicidae) Influences Vector Competence To Plasmodium Falciparum Parasites, Bernard A. Okech, Louis C. Gouagna, Guiyun Yan, John I. Githure, John C. Beier

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Background. The origin of highly competent malaria vectors has been linked to productive larval habitats in the field, but there isn't solid quantitative or qualitative data to support it. To test this, the effect of larval habitat soil substrates on larval development time, pupation rates and vector competence of Anopheles gambiae to Plasmodium falciparum were examined. Methods. Soils were collected from active larval habitats with sandy and clay substrates from field sites and their total organic matter estimated. An. gambiae larvae were reared on these soil substrates and the larval development time and pupation rates monitored. The emerging adult mosquitoes …

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Epizootiological Importance Of Glossina Morsitans Submorsitans (Diptera: Glossinidae) (Newstead) In The Ghibe River Valley, Southwest Ethiopia, Merid Negash, Melaku Girma, Emiru Seyoum May 2007

Epizootiological Importance Of Glossina Morsitans Submorsitans (Diptera: Glossinidae) (Newstead) In The Ghibe River Valley, Southwest Ethiopia, Merid Negash, Melaku Girma, Emiru Seyoum

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The epizootiological importance of Glossina morsitans submorsitans in Ghibe River Valley was undertaken from October 2000 to September 2001. The flies were collected using baited monoconical traps. G. m. submorsitans occurred with a mean apparent density of 4.26 ± 0.49 flies/trap/day and the apparent density was characterized by an increase during the wet season and a decrease during the dry season. Among 450 G. m. submorsitans, approximately 5% were found to be infected with trypanosome. Of these infected flies, 76% were female. Nanomonas, Duttonella and Trypanozoon were the three trypanosome subgenera detected and occurred in the proportions of 57.1%, 38.1% …

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C-Methylated And C-Prenylated Isoflavonoids From Root Extract Of Desmodium Uncinatum, Salome M. Guchu, Abiy Yenesew, Muniru K. Tsanuo, Nicholas K. Gikonyo, John A. Pickett, Antony M. Hooper, Ahmed Hassanali Mar 2007

C-Methylated And C-Prenylated Isoflavonoids From Root Extract Of Desmodium Uncinatum, Salome M. Guchu, Abiy Yenesew, Muniru K. Tsanuo, Nicholas K. Gikonyo, John A. Pickett, Antony M. Hooper, Ahmed Hassanali

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A pterocarpan, 1,9-dihydroxy-3-methoxy-2-methylpterocarpan (named uncinacarpan) and two isoflavanones, 5,7-dihydroxy-2′,3′,4′-trimethoxy-6-(3-methylbut-2-enyl)isoflavanone (named uncinanone D) and 5,4′-dihydroxy-7,2′-dimethoxy-6-methylisoflavanone (named uncinanone E), were isolated from the CH2Cl2 root extract of Desmodium uncinatum (Jacq.) DC and characterised by spectroscopic methods. In addition, a rare pterocarpan edudiol and two known abietane diterpenes, 7-oxo-15-hydroxydehydroabietic acid and 7-hydroxycallitrisic acid were identified. The fraction of the root extract that was analysed induced germination of Striga hermonthica seeds, but none of the isolated compounds showed this activity. © 2006 Elsevier Ltd. All rights reserved.

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Evaluation Of Various Mulberry Morus Spp. (Moraceae) Cultivars For The Rearing Of The Bivoltine Hybrid Race Shaanshi Bv-333 Of The Silkworm Bombyx Mon (Lepidoptera: Bombycidae), V. V. Adolkar, S. K. Raina, D. M. Kimbu Mar 2007

Evaluation Of Various Mulberry Morus Spp. (Moraceae) Cultivars For The Rearing Of The Bivoltine Hybrid Race Shaanshi Bv-333 Of The Silkworm Bombyx Mon (Lepidoptera: Bombycidae), V. V. Adolkar, S. K. Raina, D. M. Kimbu

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The performance of the Bombyx mori Linnaeus bivoltine hybrid, Shaanshi BV-333, was evaluated on six mulberry cultivars of Morus spp. based on economic characters in rearing and mulberry leaf quality. The growth rate and morphological characteristics for all the cultivars were studied using several parameters. Specific characters such as disease resistance, survival percentage, cocoon weight, cocoon shell weight and single cocoon filament length were recorded during the rearing of silkworm larvae. Tested cultivars significantly differed in all parameters. Cultivars Kanva-2/M5, Thailand, Thika and S-36 exhibited superiority in rearing performance over other tested cultivars. Silkworms fed with cv. Thailand had the …

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Vision-Based Ability Of An Ant-Mimicking Jumping Spider To Discriminate Between Models, Conspecific Individuals And Prey, X. J. Nelson, R. R. Jackson Feb 2007

Vision-Based Ability Of An Ant-Mimicking Jumping Spider To Discriminate Between Models, Conspecific Individuals And Prey, X. J. Nelson, R. R. Jackson

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Myrmarachne assimilis, an ant-like (myrmecomorphic) jumping spider (Araneae, Salticidae) from the Philippines, is a Batesian mimic of Oecophylla smaragdina, the Asian weaver ant. Salticids are well known for their acute eyesight and the elaborate vision-based display behaviour they adopt during encounters with conspecific individuals, but most salticids are not myrmecomorphic. Despite its unusual morphology, M. assimilis adopts display behaviour during intraspecific interactions that is similar to the display behaviour of more typical salticids. The specificity with which M. assimilis deploys display behaviour is investigated and provides insights into this mimic's ability to differentiate, by sight alone, between models, conspecific individuals …

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Surveys For Natural Enemies Of The Tomato Red Spider Mite Tetranychus Evansi (Acari: Tetranychidae) In Northeastern And Southeastern Brazil, Komi K.M. Fiaboe, Manoel G.C. Gondim, Gilberto J. De Moraes, Callistus K.P.O. Ogol, Markus Knapp Jan 2007

Surveys For Natural Enemies Of The Tomato Red Spider Mite Tetranychus Evansi (Acari: Tetranychidae) In Northeastern And Southeastern Brazil, Komi K.M. Fiaboe, Manoel G.C. Gondim, Gilberto J. De Moraes, Callistus K.P.O. Ogol, Markus Knapp

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Surveys for predators of the tomato red spider mite Tetranychus evansi Baker & Pritchard on solanaceous plants were carried out in north-eastern and south-eastern Brazil to determine prospective species for the control of the pest in Africa. Surveys were carried out in areas identified as climatically similar to regions in Africa where T. evansi has been reported as a pest and where prospective natural enemies may be introduced. A total of 56,445 mites and insects were found in 330 samples collected from 20 different species of solanaceous plants. Tetranychus evansi was found in only three samples, on Solanum americanum Mill. …

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Distribution And Relative Importance Of Lepidopteran Cereal Stemborers And Their Parasitoids In Uganda, T. Matama-Kauma, F. Schulthess, J. A. Ogwang, J. M. Mueke, C. O. Omwega Jan 2007

Distribution And Relative Importance Of Lepidopteran Cereal Stemborers And Their Parasitoids In Uganda, T. Matama-Kauma, F. Schulthess, J. A. Ogwang, J. M. Mueke, C. O. Omwega

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Infestation levels and parasitism of lepidopteran stemborers on maize were assessed in four agroecological zones (AEZ) in Uganda. The indigenous noctuid Busseola fusca Fuller (Noctuidae) and the invasive Chilo partellus Swinhoe (Crambidae) were the most important stemborers recorded. C. partellus represented 77% of the stemborers in the Eastern AEZ while B. fusca was dominant in the other AEZs, accounting for 60-79%. The proportion of infested plants was between 16% and 45% and borer density between 0.2 and 1.0 borers per plant. There was no clear relationship between damage and stem tunneling, which is often used to estimate yield loss. Telenomus …

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Submicroscopic Plasmodium Falciparum Gametocyte Densities Frequently Result In Mosquito Infection, Petra Schneider, J. Teun Bousema, Louis C. Gouagna, Silas Otieno, Marga Van De Vegte-Bolmer, Sabah A. Omar, Robert W. Sauerwein Jan 2007

Submicroscopic Plasmodium Falciparum Gametocyte Densities Frequently Result In Mosquito Infection, Petra Schneider, J. Teun Bousema, Louis C. Gouagna, Silas Otieno, Marga Van De Vegte-Bolmer, Sabah A. Omar, Robert W. Sauerwein

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Submicroscopic Plasmodium falciparum gametocytemia (< 5,000 gametocytes/mL) is common and may result in mosquito infection. We assessed the relation between gametocyte density and mosquito infection under experimental and field conditions using real-time quantitative nucleic acid sequence-based amplification (QT-NASBA) for gametocyte quantification. Serial dilutions of NF54 P. falciparum gametocytes showed a positive association between gametocyte density and the proportion of infected mosquitoes (β = 6.1; 95% confidence interval [CI], 2.7-9.6; P = 0.001). Successful infection became unlikely below an estimated density of 250-300 gametocytes/mL. In the field, blood samples of 100 naturally infected children showed a positive association between gametocyte density and oocyst counts in mosquitoes (β = 0.38; 95% CI, 0.14-0.61; P = 0.002). The relative contribution to malaria transmission was similar for carriers with submicroscopic and microscopic gametocytemia. Our results show that transmission occurs efficiently at submicroscopic gametocyte densities and that carriers harboring submicroscopic gametocytemia constitute a considerable proportion of the human infectious reservoir. Copyright © 2007 by The American Society of Tropical Medicine and Hygiene.

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Larval Habitat Dynamics And Diversity Of Culex Mosquitoes In Rice Agro-Ecosystem In Mwea, Kenya, Ephantus J. Muturi, Josephat I. Shililu, Weidong Gu, Benjamin G. Jacob, John I. Githure, Robert J. Novak Jan 2007

Larval Habitat Dynamics And Diversity Of Culex Mosquitoes In Rice Agro-Ecosystem In Mwea, Kenya, Ephantus J. Muturi, Josephat I. Shililu, Weidong Gu, Benjamin G. Jacob, John I. Githure, Robert J. Novak

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Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter …

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Antibacterial Activity Of Apis Mellifera L. Propolis Collected In Three Regions Of Kenya, Elliud M. Muli, J. M. Maingi Jan 2007

Antibacterial Activity Of Apis Mellifera L. Propolis Collected In Three Regions Of Kenya, Elliud M. Muli, J. M. Maingi

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The present study aimed at investigating the susceptibility of the microorganisms Pseudomonas aeruginosa, Salmonella typhi, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis to ethanolic extracts of propolis (EEP) from three regions of Kenya (Taita, Tana and Samburu). Propolis was extracted using four different concentrations of ethanol: pure, 70%, 50%, and 30%. Ethanol (70%) and Streptomycin were used as controls. The agar diffusion method using filter paper disks was employed. Antibacterial activity was determined as an equivalent of the inhibition zones diameters (in millimeters) after incubation at 37°C for 24h. Significant differences in the antibacterial activities of propolis were observed among …

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Environmental Abundance Of Anopheles (Diptera: Culicidae) Larval Habitats On Land Cover Change Sites In Karima Village, Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Ephantus Muturi, Patrick Halbig, Joseph Mwangangi, R. K. Wanjogu, Enock Mpanga, Jose Funes, Josephat Shililu, John Githure, James L. Regens, Robert J. Novak Jan 2007

Environmental Abundance Of Anopheles (Diptera: Culicidae) Larval Habitats On Land Cover Change Sites In Karima Village, Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Ephantus Muturi, Patrick Halbig, Joseph Mwangangi, R. K. Wanjogu, Enock Mpanga, Jose Funes, Josephat Shililu, John Githure, James L. Regens, Robert J. Novak

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A study was carried out at Karima Village in the Mwea Rice Irrigation Scheme in Kenya to assess the impact of rice husbandry and associated land cover change for mosquito larval abundance. A multi-temporal, land use land cover (LULC) classification dataset incorporating distributions of Anopheles arabiensis aquatic larval habitats was produced in ERDAS Imagine version 8.7 using combined images from IKONOS at 4m spatial resolution from 2005 and Landsat Thematic Mapper (TM)™ classification data at 30-meters spatial resolution from 1988 for Karima. Of 207 larval habitats sampled, most were either canals (53.4%) or paddies (45.9%), and only one habitat was …

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Mosquito Larval Habitats In A Semiarid Ecosystem In Eritrea: Impact Of Larval Habitat Management On Anopheles Arabiensis Population, Josephat Shililu, Charles Mbogo, Tewolde Ghebremeskel, John Githure, Robert Novak Jan 2007

Mosquito Larval Habitats In A Semiarid Ecosystem In Eritrea: Impact Of Larval Habitat Management On Anopheles Arabiensis Population, Josephat Shililu, Charles Mbogo, Tewolde Ghebremeskel, John Githure, Robert Novak

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This study investigated the impact of larval management and the temporal variation in larval productivity in Eritrea, a semiarid ecosystem. Results of this study show that mosquito breeding persists throughout the year mainly in stream bed pools. Anopheles arabiensis production in the ephemeral natural aquatic habitats such the streambed pools was high throughout the year and negatively associated with rainfall (r = -0.288, P = 0.047). High densities of An. arabiensis larvae were also recorded from canals and drainage channels at wells and communal water supply points. The numerous water supply locations and wells help sustain malaria transmission by serving …

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Nutrient Contents Of Pride Of Barbados (Caesalpinia Pulcherrima Linn.) Seeds, A. A. Yusuf, B. M. Mofio, A. B. Ahmed Jan 2007

Nutrient Contents Of Pride Of Barbados (Caesalpinia Pulcherrima Linn.) Seeds, A. A. Yusuf, B. M. Mofio, A. B. Ahmed

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Physical parameters and nutrient contents of the whole seeds and seed nuts of Caesalpinia pulcherrima L. were determined using gravimetric, Spectrophotometric and titrimetric method of analyses. Organic matter was high in both whole seeds and seed nuts 93.78-95.50 %, followed by dry matter 90.95-92.70 %. Crude protein was between 42.97-48.08%, carbohydrate was found to be 18.30-39.10%, crude fibre was between 5.98-9.06 %, crude lipid 5.65-6.0 %, and moisture content was between 7.30-9.05 % in whole seeds and seed nuts respectively. Abundance of mineral elements in whole seeds and seed nuts of C. pulcherrima were found to be in the order: …

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Farmers' Perceptions Of Importance, Control Practices And Alternative Hosts Of Maize Stemborers In Uganda, T. Kalule, Z. R. Khan, G. Bigirwa, J. Alupo, S. Okanya, J. A. Pickett, L. J. Wadhams Dec 2006

Farmers' Perceptions Of Importance, Control Practices And Alternative Hosts Of Maize Stemborers In Uganda, T. Kalule, Z. R. Khan, G. Bigirwa, J. Alupo, S. Okanya, J. A. Pickett, L. J. Wadhams

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A survey was conducted in Tororo, Bugiri and Kapchorwa districts in eastern and northeastern Uganda on farmers' perceptions of constraints in maize production. Farmers in Tororo and Bugiri consistently ranked stemborers and striga as the major production constraints in maize growing, while those in Kapchorwa ranked stemborers and lack of capital as the most important. Approximately 35 and 40% of the farmers in Tororo and Bugiri, respectively, identified stemborers as the 'caterpillar' that destroys their maize. In Kapchorwa, 50% of the farmers identified stemborers. Pesticide application was the most common control measure while the use of indigenous and cultural control …

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A Predator From East Africa That Chooses Malaria Vectors As Preferred Prey, Ximena J. Nelson, Robert R. Jackson Dec 2006

A Predator From East Africa That Chooses Malaria Vectors As Preferred Prey, Ximena J. Nelson, Robert R. Jackson

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Background. All vectors of human malaria, a disease responsible for more than one million deaths per year, are female mosquitoes from the genus Anopheles. Evarcha culicivora is an East African jumping spider (Salticidae) that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey. Methodology/Principal Findings. By testing with motionless lures made from mounting dead insects in lifelike posture on cork discs, we show that E. culicivora selects Anopheles mosquitoes in preference to other mosquitoes and that this predator can identify Anopheles by static appearance alone. Tests using active (grooming) virtual mosquitoes rendered in 3-D animation show …

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Host Shift To Peas In The Diamondback Moth Plutella Xylostella (Lepidoptera: Plutellidae) And Response Of Its Parasitoid Diadegma Mollipla (Hymenoptera: Ichneumonidae), A. Rossbach, B. Löhr, S. Vidal Dec 2006

Host Shift To Peas In The Diamondback Moth Plutella Xylostella (Lepidoptera: Plutellidae) And Response Of Its Parasitoid Diadegma Mollipla (Hymenoptera: Ichneumonidae), A. Rossbach, B. Löhr, S. Vidal

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Host shifts in herbivorous insects are thought to sometimes provide enemy-free space on the novel host plant. A population of the diamondback moth Plutella xylostella (Linnaeus), an oligophagous pest on crucifers, recently shifted to sugar snap- and snowpeas (Pisum sativum) in Kenya, resulting in heavy damage to these crops. The impact of this host shift on the interaction with Diadegma mollipla (Holmgren), one of the most frequent parasitoid species attacking P. xylostella in this area, was investigated. Parasitism rates and development of two strains of D. mollipla, one reared from a cabbage-feeding strain of P. xylostella and the second from …

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Differential Induction Of Proteins In Anopheles Gambiae Sensu Stricto (Diptera: Culicidae) Larvae In Response To Heavy Metal Selection, Paul Odhiambo Mireji, Joseph Keating, Eucharia Kenya, Charles Mbogo, Hudson Nyambaka, Ellie Osir, John Githure, John Beier Dec 2006

Differential Induction Of Proteins In Anopheles Gambiae Sensu Stricto (Diptera: Culicidae) Larvae In Response To Heavy Metal Selection, Paul Odhiambo Mireji, Joseph Keating, Eucharia Kenya, Charles Mbogo, Hudson Nyambaka, Ellie Osir, John Githure, John Beier

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Investigations were conducted to establish the magnitude and pattern of differential expression of proteins due to generational selection of third instar Anopheles gambiae s.s. Giles larvae by cadmium, copper and lead heavy metals, the three possible common urban pollutants. A susceptible strain of A. gambiae s.s. third instar larvae was separately placed under selection pressure with cadmium, copper and lead at LC30 and controls through five generations. First, third and fifth generation selection survivors were screened for differentially expressed proteins relative to non-exposed control by two-dimensional gel electrophoresis. Distribution patterns of the spots were analyzed by χ2 or Fishers' exact …

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Survival Of Immature Anopheles Arabiensis (Diptera: Culicidae) In Aquatic Habitats In Mwea Rice Irrigation Scheme, Central Kenya, Joseph M. Mwangangi, Ephantus J. Muturi, Josephat Shililu, Simon M. Muriu, Benjamin Jacob, Ephantus W. Kabiru, Charles M. Mbogo, John Githure, Robert Novak Nov 2006

Survival Of Immature Anopheles Arabiensis (Diptera: Culicidae) In Aquatic Habitats In Mwea Rice Irrigation Scheme, Central Kenya, Joseph M. Mwangangi, Ephantus J. Muturi, Josephat Shililu, Simon M. Muriu, Benjamin Jacob, Ephantus W. Kabiru, Charles M. Mbogo, John Githure, Robert Novak

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Background: The survivorship and distribution of Anopheles arabiensis larvae and pupae was examined in a rice agroecosystem in Mwea Irrigation Scheme, central Kenya, from August 2005 to April 2006, prior to implementation of larval control programme. Methods: Horizontal life tables were constructed for immatures in semi-field condition. The time spent in the various immature stages was determined and survival established. Vertical life tables were obtained from five paddies sampled by standard dipping technique. Results: Pre-adult developmental time for An. arabiensis in the trays in the experimental set up in the screen house was 11.85 days from eclosion to emergence. The …

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Electrophysiological Responses Of The Lepidopterous Stemborers Chilo Partellus And Busseola Fusca To Volatiles From Wild And Cultivated Host Plants, M. A. Birkett, K. Chamberlain, Z. R. Khan, J. A. Pickett, T. Toshova, L. J. Wadhams, C. M. Woodcock Nov 2006

Electrophysiological Responses Of The Lepidopterous Stemborers Chilo Partellus And Busseola Fusca To Volatiles From Wild And Cultivated Host Plants, M. A. Birkett, K. Chamberlain, Z. R. Khan, J. A. Pickett, T. Toshova, L. J. Wadhams, C. M. Woodcock

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The stemborers Chilo partellus and Busseola fusca are major pests of subsistence cereal farming in Africa. Volatiles released by two cultivated hosts, sorghum and maize (Sorghum bicolor and Zea mays), and two wild grass hosts, Pennisetum purpureum and Hyparrhenia tamba, were collected by air entrainment. Electrophysiologically active components in these samples were detected by coupled gas chromatography-electroantennography (GC-EAG), and the active peaks identified by gas chromatography-mass spectrometry. A total of 41 compounds were identified from the four plant species, all of which, as well as two unidentified compounds, elicited an electrophysiological response from one or both of the stemborers. The …

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Development Of Pcr-Based Chloroplast Dna Markers That Characterize Domesticated Cowpea (Vigna Unguiculata Ssp. Unguiculata Var. Unguiculata) And Highlight Its Crop-Weed Complex, Y. Feleke, R. S. Pasquet, P. Gepts Nov 2006

Development Of Pcr-Based Chloroplast Dna Markers That Characterize Domesticated Cowpea (Vigna Unguiculata Ssp. Unguiculata Var. Unguiculata) And Highlight Its Crop-Weed Complex, Y. Feleke, R. S. Pasquet, P. Gepts

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In 1992, Vaillancourt and Weeden discovered a very important mutation for studying cowpea evolution and domestication. A loss of a BamHI restriction site in chloroplast DNA characterized all domesticated accessions and a few wild (Vigna unguiculata ssp. unguiculata var. spontanea) accessions. In order to screen a larger number of accessions, primers were designed to check this mutation using PCR RFLP or direct PCR methods. Using these new primers, 54 domesticated cowpea accessions and 130 accessions from the wild progenitor were screened. The absence of haplotype 0 was confirmed within domesticated accessions, including primitive landraces from cultivar-groups Biflora and Textilis, suggesting …

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A Grid-Based Infrastructure For Ecological Forecasting Of Rice Land Anopheles Arabiensis Aquatic Larval Habitats, Benjamin G. Jacob, Ephantus J. Muturi, Jose E. Funes, Josephat I. Shililu, John I. Githure, Ibulaimu I. Kakoma, Robert J. Novak Oct 2006

A Grid-Based Infrastructure For Ecological Forecasting Of Rice Land Anopheles Arabiensis Aquatic Larval Habitats, Benjamin G. Jacob, Ephantus J. Muturi, Jose E. Funes, Josephat I. Shililu, John I. Githure, Ibulaimu I. Kakoma, Robert J. Novak

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Background: For remote identification of mosquito habitats the first step is often to construct a discrete tessellation of the region. In applications where complex geometries do not need to be represented such as urban habitats, regular orthogonal grids are constructed in GIS and overlaid on satellite images. However, rice land vector mosquito aquatic habitats are rarely uniform in space or character. An orthogonal grid overlaid on satellite data of rice-land areas may fail to capture physical or man-made structures, i.e paddies, canals, berms at these habitats. Unlike an orthogonal grid, digitizing each habitat converts a polygon into a grid cell, …

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Simultaneous Application Of Entomopathogenic Nematodes And Predatory Mites To Control Western Flower Thrips Frankliniella Occidentalis, Lemma Ebssa, Christian Borgemeister, Hans Michael Poehling Oct 2006

Simultaneous Application Of Entomopathogenic Nematodes And Predatory Mites To Control Western Flower Thrips Frankliniella Occidentalis, Lemma Ebssa, Christian Borgemeister, Hans Michael Poehling

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Effects of entomopathogenic nematodes alone (Heterorhabditis bacteriophora Poinar or H. indica Poinar, Karunakar, and David), a predatory mite species alone [Amblyseius cucumeris (Oudemans) (Acarina: Phytoseiidae)], or the combination of nematodes and mites for the control of the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) was investigated in a climate controlled growth chamber and greenhouse. Different densities and concentrations of mites and nematodes, respectively, were tested at different densities of thrips infesting beans (Phaseolus vulgaris L.). In the growth chamber experiment, the presence of mites on the plants resulted in a large number of second-instar larvae of thrips to fall …

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