IN VITRO PROPAGATION OF THREE COMMERCIAL PASSIONFRUIT VARIETIES IN UGANDA

Small purple ( Passiflora edulis f. edulis ) and yellow ( P. edulis f. flavicarpa ) and KPF 4 (a cross between the two varieties) passionfruit varieties are of high economic importance in Uganda. Production of passionfruit is greatly constrained by viral diseases, leading to significant yield losses. This is aggravated by lack of adequate quantities of clean planting material. In vitro propagation through nodal sections is one way that has been successful in rapidly producing planting materials of vegetatively propagated crops that are clean and true-to-type. This study was aimed at obtaining optimum in vitro growth conditions for rapid micropropagation of the commercial passionfruit varieties in Uganda. Surface sterilised nodal sections from two month old plants were used as explants. For shoot regeneration, explants were cultured on Murashige and Skoog (MS) media, supplemented with varying concentrations of 6-Benzylaminopurine (BAP), either singly or in combination with Kinetin (KIN). Rooting MS media was fortified with varying concentrations of 1-Naphthalene acetic acid (NAA), either singly or in combination with BAP. MS medium supplemented with a combination of 2 mg l-1 BAP and 0.5 mg l-1 KIN, optimally supported shoot regeneration of the three passionfruit varieties. The average number of shoots and shoot height were 3.3 and 3.1 cm, respectively. Optimal root development was observed on MS media containing 3 mg l-1 NAA, with a mean number of 5.5 leaves and a length of 2.4 cm. The rooted in vitro plantlets were successfully established in a potting mixture containing loam soil and manure in ratio of 1:1.Les vari\ue9t\ue9s de fruit de la passion petit violet ( Passiflora edulis f. edulis ), jaune ( P. edulis f. flavicarpa ) et KPF 4 (croisement r\ue9alis\ue9 entre les deux vari\ue9t\ue9s pr\ue9c\ue9dentes) sont d\u2019une importance \ue9conomique tr\ue8s \ue9lev\ue9e en Ouganda. La production du fruit de la passion est sujette \ue0 aux maladies virales, causant d\u2019\ue9normes pertes de rendement. Ceci est aggrav\ue9 par l\u2019inexistence en quantit\ue9 suffisante des semences de qualit\ue9. La propagation In vitro au moyen des sections nodales, est un proc\ue9d\ue9 qui a connu du succ\ue8s dans la production rapide des semences de bonne qualit\ue9 chez les plantes \ue0 propagation vegetative. La pr\ue9sente \ue9tude a \ue9t\ue9 r\ue9alis\ue9e afin de d\ue9terminer les conditions optimales de croissance in vitro en vue d\u2019une micropropagation rapide des vari\ue9t\ue9s commerciales de fruit de la passion en Ouganda. Des sections nodales pr\ue9lev\ue9es sur des plants de fruit de la passion ages de deux mois, ont \ue9t\ue9 st\ue9rilis\ue9es en surface et utilis\ue9es comme explants. Pour la r\ue9g\ue9n\ue9ration plantulaire, les explants ont \ue9t\ue9 cultiv\ue9s sur des milieu de culture Murashige et Skoog (MS), additionn\ue9s de diverses concentrations de 6- Benzylaminopurine (BAP), soit uniquement ou en combinaison avec de la Kinetine (KIN). Le milieu de culture MS pour la croissance racinaire a \ue9t\ue9 renforc\ue9 avec diverses concentrations de 1-Naphthalene acide ac\ue9tique (NAA), soit uniquement ou en combinaison avec BAP. Le milieu MS additionn\ue9 de 2 mg l-1 BAP et 0,5 mg l-1 KIN, a permis une r\ue9g\ue9n\ue9ration optimale des explants des trois vari\ue9t\ue9s test\ue9es. Le nombre moyen de plantule et la longueur des racines \ue9taient respectivement de 3,3 et 3,1 cm. Un d\ue9veloppement racinaire optimal a \ue9t\ue9 observe sur milieu MS contenant 3 mg l-1 NAA, avec une moyenne de 5,5 feuilles et une longueur moyenne de 2,4 cm. les plantules in vitro ont repiqu\ue9es sur pots contenant un m\ue9lange de sol argileux et de la fumure dans des proportions 1:1

Dynamics, stratospheric ozone, and climate change

Dynamics affects the distribution and abundance of stratospheric ozone directly through transport of ozone itself and indirectly through its effect on ozone chemistry via temperature and transport of other chemical species. Dynamical processes must be considered in order to understand past ozone changes, especially in the northern hemisphere where there appears to be significant low-frequency variability which can look “trend-like” on decadal time scales. A major challenge is to quantify the predictable, or deterministic, component of past ozone changes. Over the coming century, changes in climate will affect the expected recovery of ozone. For policy reasons it is important to be able to distinguish and separately attribute the effects of ozone-depleting substances and greenhouse gases on both ozone and climate. While the radiative-chemical effects can be relatively easily identified, this is not so evident for dynamics — yet dynamical changes (e.g., changes in the Brewer-Dobson circulation) could have a first-order effect on ozone over particular regions. Understanding the predictability and robustness of such dynamical changes represents another major challenge. Chemistry-climate models have recently emerged as useful tools for addressing these questions, as they provide a self-consistent representation of dynamical aspects of climate and their coupling to ozone chemistry. We can expect such models to play an increasingly central role in the study of ozone and climate in the future, analogous to the central role of global climate models in the study of tropospheric climate change

Automated Structure Solution with the PHENIX Suite

Significant time and effort are often required to solve and complete a macromolecular crystal structure. The development of automated computational methods for the analysis, solution and completion of crystallographic structures has the potential to produce minimally biased models in a short time without the need for manual intervention. The PHENIX software suite is a highly automated system for macromolecular structure determination that can rapidly arrive at an initial partial model of a structure without significant human intervention, given moderate resolution and good quality data. This achievement has been made possible by the development of new algorithms for structure determination, maximum-likelihood molecular replacement (PHASER), heavy-atom search (HySS), template and pattern-based automated model-building (RESOLVE, TEXTAL), automated macromolecular refinement (phenix.refine), and iterative model-building, density modification and refinement that can operate at moderate resolution (RESOLVE, AutoBuild). These algorithms are based on a highly integrated and comprehensive set of crystallographic libraries that have been built and made available to the community. The algorithms are tightly linked and made easily accessible to users through the PHENIX Wizards and the PHENIX GUI

Macrosocial determinants of population health in the context of globalization

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55738/1/florey_globalization_2007.pd

Discovery of genes associated with fruit ripening in arica papaya using expressed sequence tags

To identify genes involved in papaya fruit ripening, a total of 1171 expressed sequence tags (ESTs) were generated from randomly selected clones of two independent fruit cDNA libraries derived from yellow and red-fleshed fruit varieties. The most abundant sequences encoded: chitinase, 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, catalase and methionine synthase, respectively. DNA sequence comparisons identified ESTs with significant similarity to genes associated with fruit softening, aroma and colour biosynthesis. Putative cell wall hydrolases, cell membrane hydrolases, and ethylene synthesis and regulation sequences were identified with predicted roles in fruit softening. Expressed papaya genes associated with fruit aroma included isoprenoid biosynthesis and shikimic acid pathway genes and proteins associated with acyl lipid catabolism. Putative fruit colour genes were identified due to their similarity with carotenoid and chlorophyll biosynthesis genes from other plant species