TDZ AND 4-CPPU in Gamborg B5 salts with MS vitamins doubles embryogenic 191 response from male flowers of EA-AAA banana.

Conventionally, auxins have been used in MS medium in combination or without purine-based cytokinins for induction of embryogenesis in EA-AAA banana (Musa spp.). Besides, low embryogenic response, it has been rare for more than two cultivars to respond similarly to a single treatment. This study investigated the efficacy of urea-type cytokinins, N-phenyl-N’-1,2,3-thidiazol-5-ylurea (TDZ) and N-(2-chloro-4-pyridyl)-N'-phenylurea (4-CPPU); and salt formulations, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH and White for embryogenic callus induction in different EA-AAA banana cultivars. Immature male flowers of cultivars Mpologoma, Mbwazirume, Nakabululu, Nakinyika and Nfuuka were cultured on callus induction medium, supplemented with different TDZ and 4-CPPU combinations. Most of the cultivars had embryogenic response to the medium with 10μM TDZ+10μM CPPU. Cultivar Nakabululu recorded 22.2% embryogenic response, followed by Mwazirume (5.7%), Nakinyika (5.3%) and Mpologoma (4.6%). Cultivar Nfuuka had 9.1% embryogenic response on 15μM TDZ+15μM CPPU. When cultivars Mpologoma and Nakinyika were cultured on the same medium containing 10μM TDZ+10μM CPPU, but the MS salts substituted with the other salt formulations, their cultures recorded 11.4 and 8.3% embryogenic response, respectively to Gamborg B5 salts; which was almost twice their response to MS medium. The results suggested that TDZ and 4-CPPU, particularly in Gamborg B5 salt formulation, could increase percentage of embryogenic callus induced from male flowers of EA-AAA banana cultivars, and would improve plant regeneration and consequently help in the process of genetic improvement of EA-AAA banana.Key Words: Cytokinins, embryogenic response, Musa spp., Thidiazuro

Prevalence of viruses infecting cowpea in Uganda and their molecular detection

The main areas for cowpea cultivation in Uganda were surveyed in June and October 2006 for viruses affecting the crop. Seed and leaf samples from symptomatic and asymptomatic plants were collected from farmers’ fields and analysed for infecting viruses using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). The viruses detected in the leaf and seed samples were: cucumber mosaic cucumovirus (CMV), cowpea mild mottle calarvirus (CPMMV), cowpea mottle carmovirus (CPMoV), Cowpea chlorotic mottle bromovirus (CCMV), Cowpea yellow mosaic comovirus (CYMV), cowpea severe mosaic comovirus (CPSMV), cowpea aphid-borne mosaic potyvirus (CABMV) and Southern bean mosaic sobemovirus (SBMV). CPMV was detected only in leaf samples. CMV and CABMV were later confirmed using reverse transcription polymerase chain reaction (RT-PCR). Of the viruses detected in leaf samples, 53.26% occurred as single infections, 24.46% dual and 22.28% multiple infections. Similarly, analysis of seed samples revealed infection of 40.6, 34.6 and 24.8% for single, dual and multiple infections, respectively. Multiple virus infections were associated with more disease severity and higher yield losses. The seed transmission levels of 23.0, 20.3 and 16.4% were recorded for CMV, CPMMV and CABMV, respectively. This study identified six more viruses in addition to what was previously reported in the country, of which eight were seed-borne. This necessitates the need for the production and use of virus-free seeds, development of virus resistant genotypes and adoption of efficient seed certification systems.Keywords: Vigna unguiculata, disease incidence, seed-borne viruses, ELISA, (RT-PCR

BANANA JUICE AS AN ALTERNATIVE ENERGY SOURCE FOR BANANA IN VITRO GROWTH MEDIUM

Energy sources in tissue culture media are important for plants whose photosynthetic efficiency is insufficient under in vitro conditions. However, the cost of tissue culture grade energy sources is high, thus making tissue culture derived plantlets expensive. The cost of table sugar commonly used in commercial tissue culture laboratories and a substitute for tissue culture grade sucrose in Uganda, is also relatively high given the volumes used. The aim of this study was to evaluate the possibility of exploiting banana ( Musa spp.) juice, as an energy source in place of table sugar or tissue culture grade sucrose. Banana juice was extracted from the locally available East African Highland Banana (EAHB) beer cultivars, Mbidde-Kabula, Pisang awak (Kayinja) and Km 5, and used at levels of 20, 30, 40 and 50 ml l-1. The quality and amount of juice necessary to support in vitro growth of cooking EAHB cultivars Nakabululu, Nakitembe and Nakinyika was evaluated. The juice had varied composition of salts, sugars and organic acids; but with pH compared with table sugar solution. The highest number of shoots and shoot height was observed when bananas were cultured on media supplemented with 50 ml l-1 Kayinja juice. This response was greater than that observed with culture media supplemented with the control energy source of 30 g l-1 of table sugar. Results also showed that banana juice not only enhanced micropropagation but also improved in vitro plantlet vigour and reduced the cost of energy sources by 30%.Les sources d\u2019\ue9nergies sont importantes dans les milieux de culture in-vitro des plantes dont l\u2019efficacit\ue9 photosynth\ue9tique est insuffisante dans les conditions de culture in-vitro . Cependant, le co\ufbt des sources d\u2019\ue9nergies utilis\ue9es en culture in-vitro de tissus est \ue9lev\ue9, ceci rend couteux les plantules produites par culture in-vitro. Le co\ufbt du sucre de table habituellement utilis\ue9 dans les laboratoires commerciaux de culture de tissus in-vitro ainsi que celui du substitut de sucrose utilis\ue9 en Ouganda reste relativement \ue9lev\ue9, \ue9tant donn\ue9 les volumes utilis\ue9s. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la possibilit\ue9 d\u2019exploiter le suc de bananier ( Musa spp.), comme une source d\u2019\ue9nergie en lieu et place du sucre de table ou du sucrose. Le suc de bananier a \ue9t\ue9 extrait des vari\ue9t\ue9s de bananier localement disponible\ua0; bananier de terre ferme de l\u2019Afrique de l\u2019Est (EAHB), Mbidde-Kabula, Pisang awak (Kayinja) and Km 5, et utilis\ue9 \ue0 diff\ue9rentes concentrations telles que 20, 30, 40 and 50 ml l-1. La qualit\ue9 et la quantit\ue9 de suc n\ue9cessaire pour assurer la croissance in-vitro des vari\ue9t\ue9s EAHB, Nakabululu, Nakitembe and Nakinyika a \ue9t\ue9 \ue9valu\ue9. Le suc avait des concentrations vari\ue9es en sels, sucres et acides organiques; mais avec un pH comparable \ue0 celui du sucre de table en solution. Le plus grand nombre de rejetons et les pousses les plus hautes ont \ue9t\ue9 obtenues lorsque les tissus du bananier sont cultiv\ue9s dans un milieu contenant 50 ml l-1 de suc de Kayinja. Cette r\ue9ponse \ue9tait plus \ue9lev\ue9e que celle obtenue avec culture sur un milieu t\ue9moin (30 g l-1 de sucre de table). Les r\ue9sultats indiquent que le suc de bananier au-del\ue0 de renforcer la micro propagation, am\ue9liore aussi la vigueur des plantules en verre et r\ue9duit de 30% le co\ufbt des sources d\u2019\ue9nergies utilis\ue9es en culture de tissus in-vitro

Expression of a rice chitinase gene in transgenic banana (''Gros Michel'', AAA genome group) confers resistance to black leaf streak disease

Transgenic banana (Musa acuminata 'Gros Michel') integrating either of two rice chitinase genes was generated and its resistance to Black Leaf Streak disease caused by the fungus Mycosphaerella fijiensis was tested using a leaf disk bioassay. PCR screening indicated the presence of the hpt selectable marker gene in more than 90 % of the lines tested, whereas more than three quarters of the lines contained the linked rice chitinase gene resulting in a co-transformation frequency of at least 71.4 %. Further, a unique stable integration of the transgenes in each line revealed some false negative PCR results and the expected co-transformation frequency of 100 %

TDZ AND 4-CPPU IN GAMBORG B5 SALTS WITH MS VITAMINS DOUBLES EMBRYOGENIC RESPONSE FROM MALE FLOWERS OF EA-AAA BANANA

Conventionally, auxins have been used in MS medium in combination or without purine-based cytokinins for induction of embryogenesis in EA-AAA banana ( Musa spp.). Besides, low embryogenic response, it has been rare for more than two cultivars to respond similarly to a single treatment. This study investigated the efficacy of urea-type cytokinins, N-phenyl-N\u2019-1,2,3-thidiazol-5-ylurea (TDZ) and N-(2-chloro-4-pyridyl)-N\u2019-phenylurea (4-CPPU); and salt formulations, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH and White for embryogenic callus induction in different EA-AAA banana cultivars. Immature male flowers of cultivars Mpologoma, Mbwazirume, Nakabululu, Nakinyika and Nfuuka were cultured on callus induction medium, supplemented with different TDZ and 4-CPPU combinations. Most of the cultivars had embryogenic response to the medium with 10\ub5M TDZ+10\ub5M CPPU. Cultivar Nakabululu recorded 22.2% embryogenic response, followed by Mwazirume (5.7%), Nakinyika (5.3%) and Mpologoma (4.6%). Cultivar Nfuuka had 9.1% embryogenic response on 15\ub5M TDZ+15\ub5M CPPU. When cultivars Mpologoma and Nakinyika were cultured on the same medium containing 10\ub5M TDZ+10\ub5M CPPU, but the MS salts substituted with the other salt formulations, their cultures recorded 11.4 and 8.3% embryogenic response, respectively to Gamborg B5 salts; which was almost twice their response to MS medium. The results suggested that TDZ and 4-CPPU, particularly in Gamborg B5 salt formulation, could increase percentage of embryogenic callus induced from male flowers of EA-AAA banana cultivars, and would improve plant regeneration and consequently help in the process of genetic improvement of EA-AAA banana.Conventionnellement, les auxines ont \ue9t\ue9 utilisees dans le medium MS en combinaison avec ou sans cytokinines \ue0 base de purine pour induction de l\u2019embryogen\ue8se dans la banane EA-AAA ( Musa spp.). En plus d\u2019une faible r\ue9ponse embryog\ue9nique, il a \ue9t\ue9 rare pour plus de deux cultivars de r\ue9pondre de fa\ue7on similaire \ue0 un seul traitement. Cette \ue9tude a \ue9t\ue9 conduite pour \ue9valuer l\u2019efficacit\ue9 des cytokinines de type urea, N-phenyl-N\u2019-1,2,3-thidiazol-5-ylurea (TDZ) et N-(2-chloro-4-pyridyl)-N\u2019-phenylurea (4-CPPU)\ua0; et les formulations du sel, Chu (N6), Eriksson, Gamborg B5, MS, Nitsch, NLN, SH et blanc pour l\u2019 induction du callus embryog\ue9nique dans diff\ue9rents cultivars de banane EA-AAA. Des cultivars Mpologoma des fleurs males immatures Mbwazirume, Nakabululu, Nakinyika et Nfuuka \ue9taient cultiv\ue9s sur le medium d\u2019induction du callus, suppl\ue9ment\ue9e avec diff\ue9rentes combinaisons de TDZ et 4-CPPU. La plupart des cultivars avaient une r\ue9ponse embryog\ue9nique au medium avec 10\ub5M TDZ+10\ub5M CPPU. Le cultivar Nakabululu a r\ue9alis\ue9 22.2% de r\ue9ponse embryog\ue9nique, suivi de Mbwazirume (5.7%), Nakinyika (5.3%) et Mpologoma (4.6%). Le cultivar Nfuuka avait 9.1% de r\ue9ponse embryog\ue9nique sur 15\ub5M TDZ+15\ub5M CPPU. Lorsque les cultivars Mpologoma et Nakinyika \ue9taient cultiv\ue9s sur le m\ueame medium contenant 10\ub5M TDZ+10\ub5M CPPU, mais les sels MS substitu\ue9s par d\u2019autres formulations de sels, leurs cultures ont enregistr\ue9 11.4 et 8.3% de r\ue9ponses embryog\ue9niques, respectivement, aux sels Gamborg B5; qui faisait presque le double de leur r\ue9ponse au medium MS. Les r\ue9sultats ont sugg\ue8rent que TDZ et 4-CPPU, particuli\ue8rement dans la formulation du sel Gamborg B5, pourrait augmenter le pourcentage induit du callus embryog\ue9nique des fleurs males des cultivars de banane EA-AAA et pourrait am\ue9liorer la r\ue9g\ue9n\ue9ration des plants et en cons\ue9quence aider dans le processus de l\u2019am\ue9lioration g\ue9n\ue9tique de la banane EA-AAA

Measuring socioeconomic inequalities in relation to malaria risk: a comparison of metrics in rural Uganda

ocioeconomic position (SEP) is an important risk factor for malaria, but there is no consensus on how to measure SEP in malaria studies. We evaluated the relative strength of four indicators of SEP in predicting malaria risk in Nagongera, Uganda. 318 children resident in 100 households were followed for 36 months to measure parasite prevalence routinely every three months and malaria incidence by passive case detection. Household SEP was determined using: (1) two wealth indices, (2) income, (3) occupation and (4) education. Wealth Index I (reference) included only asset ownership variables. Wealth Index II additionally included food security and house construction variables, which may directly affect malaria. In multivariate analysis, only Wealth Index II and income were associated with the human biting rate, only Wealth Indices I and II were associated with parasite prevalence and only caregiver’s education was associated with malaria incidence. This is the first evaluation of metrics beyond wealth and consumption indices for measuring the association between SEP and malaria. The wealth index still predicted malaria risk after excluding variables directly associated with malaria, but the strength of association was lower. In this setting, wealth indices, income and education were stronger predictors of socioeconomic differences in malaria risk than occupation

An assessment of the readiness for introduction of the HPV vaccine in Uganda

Formative research assessing human papillomavirus (HPV) vaccine readiness in Uganda was conducted in 2007. The objective was to generate evidence for government decision-making and operationalplanning for HPV vaccine introduction. Qualitative research methods with children, parents, teachers, community leaders, health workers, technical experts and political leaders were used to captureunderstanding of socio-cultural, health system and policy environments. We found low levels of knowledge about cervical cancer and HPV. Vaccination and its benefits were well-understood;respondents were positive about HPV vaccination. Health systems were deemed adequate for HPV vaccine delivery. Schools were identifie as a vaccination venue, given high attendance by girls aged10-12 years. Communication and advocacy strategies to foster acceptance should provide information on cervical cancer, HPV vaccine safety, and side effects. Policymakers requested further detail on costs.Introduction of HPV vaccine could be integrated into existing reproductive health and immunization policies (Afr J Reprod Health 2008; 12[3]:159-172)

Protective effi cacy of prolonged co-trimoxazole prophylaxis in HIV-exposed children up to age 4 years for the prevention of malaria in Uganda: a randomised controlled open-label trial

Background WHO recommends daily co-trimoxazole for children born to HIV-infected mothers from 6 weeks of age until breastfeeding cessation and exclusion of HIV infection. We have previously reported on the eff ectiveness of continuation of co-trimoxazole prophylaxis up to age 2 years in these children. We assessed the protective effi cacy and safety of prolonging co-trimoxazole prophylaxis until age 4 years in HIV-exposed children. Methods We undertook an open-label randomised controlled trial alongside two observational cohorts in eastern Uganda, an area with high HIV prevalence, malaria transmission intensity, and antifolate resistance. We enrolled HIVexposed infants between 6 weeks and 9 months of age and prescribed them daily co-trimoxazole until breastfeeding cessation and HIV-status confi rmation. At the end of breastfeeding, children who remained HIV-uninfected were randomly assigned (1:1) to discontinue co-trimoxazole or to continue taking it up to age 2 years. At age 2 years, children who continued co-trimoxazole prophylaxis were randomly assigned (1:1) to discontinue or continue prophylaxis from age 2 years to age 4 years. The primary outcome was incidence of malaria (defi ned as the number of treatments for new episodes of malaria diagnosed with positive thick smear) at age 4 years. For additional comparisons, we observed 48 HIV-infected children who took continuous co-trimoxazole prophylaxis and 100 HIV-unexposed uninfected children who never received prophylaxis. We measured grade 3 and 4 serious adverse events and hospital admissions. All children were followed up to age 5 years and all analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00527800. Findings 203 HIV-exposed infants were enrolled between Aug 10, 2007, and March 28, 2008. After breastfeeding ended, 185 children were not infected with HIV and were randomly assigned to stop (n=87) or continue (n=98) co-trimoxazole up to age 2 years. At age 2 years, 91 HIV-exposed children who had remained on co-trimoxazole prophylaxis were randomly assigned to discontinue (n=46) or continue (n=45) co-trimoxazole from age 2 years to age 4 years. We recorded 243 malaria episodes (2·91 per person-years) in the 45 HIV-exposed children assigned to continue cotrimoxazole until age 4 years compared with 503 episodes (5·60 per person-years) in the 46 children assigned to stop co-trimoxazole at age 2 years (incidence rate ratio 0·53, 95% CI 0·39–0·71; p<0·0001). There was no evidence of malaria incidence rebound in the year after discontinuation of co-trimoxazole in the HIV-exposed children who stopped co-trimoxazole at age 2 years, but incidence increased signifi cantly in HIV-exposed children who stopped co-trimoxazole at age 4 years (odds ratio 1·78, 95% CI 1·19–2·66; p=0·005). Incidence of grade 3 or 4 serious adverse events, hospital admissions, or deaths did not signifi cantly diff er between HIV-exposed, HIV-unexposed, and HIV-infected children. Interpretation Continuation of co-trimoxazole prophylaxis up to 4 years of age seems safe and effi cacious to protect HIV-exposed children living in malaria-endemic areas

Why is malaria associated with poverty? Findings from a cohort study in rural Uganda

Background Malaria control and sustainable development are linked, but implementation of ‘multisectoral’ intervention is restricted by a limited understanding of the causal pathways between poverty and malaria. We investigated the relationships between socioeconomic position (SEP), potential determinants of SEP, and malaria in Nagongera, rural Uganda. Methods Socioeconomic information was collected for 318 children aged six months to 10 years living in 100 households, who were followed for up to 36 months. Mosquito density was recorded using monthly light trap collections. Parasite prevalence was measured routinely every three months and malaria incidence determined by passive case detection. First, we evaluated the association between success in smallholder agriculture (the primary livelihood source) and SEP. Second, we explored socioeconomic risk factors for human biting rate (HBR), parasite prevalence and incidence of clinical malaria, and spatial clustering of socioeconomic variables. Third, we investigated the role of selected factors in mediating the association between SEP and malaria. Results Relative agricultural success was associated with higher SEP. In turn, high SEP was associated with lower HBR (highest versus lowest wealth index tertile: Incidence Rate Ratio 0.71, 95 % confidence intervals (CI) 0.54–0.93, P = 0.01) and lower odds of malaria infection in children (highest versus lowest wealth index tertile: adjusted Odds Ratio 0.52, 95 % CI 0.35–0.78, P = 0.001), but SEP was not associated with clinical malaria incidence. Mediation analysis suggested that part of the total effect of SEP on malaria infection risk was explained by house type (24.9 %, 95 % CI 15.8–58.6 %) and food security (18.6 %, 95 % CI 11.6–48.3 %); however, the assumptions of the mediation analysis may not have been fully met. Conclusion Housing improvements and agricultural development interventions to reduce poverty merit further investigation as multisectoral interventions against malaria. Further interdisplinary research is needed to understand fully the complex pathways between poverty and malaria and to develop strategies for sustainable malaria control