VARIABILITY OF VOLATILE ORGANIC COMPOUNDS EMITTED BY SEEDLINGS OF SEVEN AFRICAN MAIZE VARIETIES WHEN INFESTED BY ADULT CICADULINA STOREYI CHINA LEAFHOPPER VECTORS OF MAIZE STREAK VIRUS

Maize ( Zea mays L.) is an important source of energy for the people in sub-Saharan Africa. Unfortunately, maize production is under the threat of Maize streak virus (MSV) (Geminiviridae: genus Mastrevirus), an endemic pathogen of native African grasses. This virus is acquired and transmitted in a persistent manner, by Cicadulina spp. leafhoppers (Homoptera: Cicadellidae) .One possibility for controlling the virus and the vectors is to exploit volatile semiochemicals released by plants following insect herbivory. A study was conducted on herbivoreinduced volatile organic compounds (VOCs) of seven African maize (Zea mays L.) varieties in the presence of the leafhopper ( Cicadulina storeyi China, Homoptera: Cicadellidae) an important vector of maize streak virus (MSV) with a view of developing novel leafhopper control strategies in sub-Saharan Africa. VOCs are known to repel herbivory and also serve as cues for parasitoids to locate their hosts. Volatiles were collected from young maize seedlings of 7 varieties after entrainment with or without infestation of leafhoppers in 0 - 24, 24 - 48, 48 - 72 and 72\u201396 hr periods and combined and subsequently analysed by gas chromatography. Analysis of the VOCs collected from the seven elite African varieties shows high interspecific VOC variability. Gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS) led to the identification of (z)-3-hexen-1-ol, heptanal, (z)- 2-pentenyl acetate, MHO, octanal, myrcene, (z)-3-hexen-1-yl acetatate, (E)-3-hexen-1-yl acetatate, nonanal Linalool, DMNT, (E)-2-decen-1-ol, Methyl salicylate, DMNT, Phenethyl acetate, Indole, cis-jasmone, \u3b1- copaene, Geranyl acetone, \u3b2-caryophyllene, \u3b1-bergamotene, (E)-\u3b2-farnesens, TMTT, and Humulene from infested seedlings. Of these, methyl salicylate, (E)-caryophyllene, (E)-\u3b2-farnesene and TMTT were identified previously as volatile semiochemicals involved in plant defense against other sucking insect pests. TZB-SR seedlings emitted 22 compounds in the presence of leafhoppers, compared with 5 by uninfested seedlings; while BR9943-DMR.SR emitted only seven compound in the presence of leafhoppers compared with 6 by uninfested seedlings. The compounds emitted by the seven maize varieties after herbivory were in the following descending order: TZB-SR > TZBR.ELD3.C3 > AMA.TZBR = 8338-1> GUSAU 81.POOL16-SR = 9021-18.STR > BR9943-DMR.SR. Although these varieties were bred for resistance to MSV and other production constraints like downy mildew and stem borers, the variability being reported would have significant ecological implications in utilising plant induced volatiles as repellents for leafhoppers in controlling MSV and underscores the need to breed for varieties that produce volatiles which are very attractive to biological control agents and repellent to leafhoppers. This is the first report of variability of maize genotypes on herbivores-induced volatiles from an African pest/pathogen complex and is in conformity with previous studies that maize shows relatively high genetic and VOC variability, both intrinsically and in herbivore-induced emissions.Le ma\uefs ( Zea mays L.) est une importante source d\u2019\ue9nergie du peuple d\u2019Afrique sub-saharienne. Malheureusement, sa production est affect\ue9e par la striure brune du ma\uefs (MSV) (Geminiviridae: genus Mastrevirus), un pathog\ue8ne end\ue9mique originaire d\u2019herbes africaines. Ce virus est acquis et transmis de mani\ue8re persistante par la Cicadelle (Homoptera: Cicadellidae). Pour contr\uf4ler ce virus et ses vecteurs, il est possible d\u2019exploiter les produits semiochimiques \ue9mis par les plantes infest\ue9es par les insects. Une \ue9tude \ue9tait effectu\ue9e sur des compos\ue9s organiques volatiles \ue9mis par sept vari\ue9t\ue9s de ma\uefs (Zea mays L.) losrqu\u2019infect\ue9es par la cicadelle ( Cicadulina storeyi China, Homoptera: Cicadellidae), un vecteur important du virus de la striure de ma\uefs (MSV) afin de d\ue9velopper des strat\ue9gies de contr\uf4l de la cicadelle en Afrique sub-saharienne. Les VOCs servent comme signaux pour les parasito\uefdes afin de localiser leurs h\uf4tes. Les volatiles \ue9taient collect\ue9s des jeunes plants des sept vari\ue9t\ue9s apr\ue8s introduction ou pas d\u2019infestation de la cicadelle \ue0 des p\ue9riodes de temps allant de 0 - 24, 24 - 48, 48 - 72 and 72\u201396 heures et combin\ue9e, plutard analys\ue9s \ue0 l\u2019aide du gaz chromatographique. L\u2019analyse des VOCs issus de sept vari\ue9t\ue9s africaines \ue9lites montre une variabilit\ue9 intersp\ue9cifique des VOCs. Le gaz chromatographique (GC) et la combinaison GC- masse sp\ue9ctrom\ue9trie (GC-MS) ont permis l\u2019identification de (z)-3-hexen-1-ol, heptanal, (z)-2-pentenyl acetate, MHO, octanal, myrcene, (z)-3-hexen-1-yl acetatate, (E)-3-hexen-1-yl acetatate, nonanal Linalool, DMNT, (E)-2-decen-1-ol, Methyl salicylate, DMNT, Phenethyl acetate, Indole, cisjasmone, \u3b1-copaene, Geranyl acetone, \u3b2-caryophyllene, \u3b1-bergamotene, (E)-\u3b2-farnesens, TMTT, et Humulene dans des plants infest\ue9es. De tous ces produits pr\ue9cit\ue9s, seuls methyl salicylate, (E)-caryophyllene, (E)-\u3b2- farnesene et TMTT \ue9taient auparavant identifi\ue9s comme volatiles semiochemiques impliqu\ue9s dans la d\ue9fence des plants contre d\u2019autres pestes d\u2019insectes suceurs des plantes. Les plants TZB-SR ont \ue9mis 22 compos\ue9s en pr\ue9sence de la cicadelle en comparaison avec 5 plants non infest\ue9s; alors que BR9943-DMR.SR ont \ue9mis seulement sept compos\ue9s en pr\ue9sence de la cicadelle en comparaison de 6 plants non infest\ue9s. Les compos\ue9s \ue9mis par les sept vari\ue9t\ue9s de ma\ubfs apr\ue8s infestation de la cicadelle \ue9taient classes comme suit par ordre descendant: TZB-SR > TZBR.ELD3.C3 >AMA.TZBR = 8338-1> GUSAU 81.POOL16-SR = 9021-18.STR > BR9943- DMR.SR. Bien que ces vari\ue9t\ue9s \ue9taient dot\ue9es de r\ue9sistance au MSV et autres contraintes \ue0 la production comme le mildew et le stem borers, la variabilit\ue9 manifest\ue9e pourrait avoir des implications \ue9cologiques significatives dans l\u2019utilisation des compos\ue9s volatiles \ue9mis des plantes comme moyen de repousser les cicadelles dans le contr\uf4l du MSV. Ceci souligne le besoin d\u2019entreprendre des \ue9tudes d\u2019am\ue9lioration g\ue9n\ue9tique des vari\ue9t\ue9s pouvant \ue9mettre des compos\ue9s volatiles comme agent de contr\uf4l biologique et repulsif de la cicadelle. Ceci constitue le premier rapport sur la variabilit\ue9 des g\ue9notypes de ma\ubfs eu \ue9gard aux compos\ue9s volatiles organiques \ue9mis \ue0 partir du complexe de peste/pathog\ue8ne africain. Ceci est en conformit\ue9 avec des \ue9tudes ant\ue9rieures qui montrent une relative variabilit\ue9 g\ue9n\ue9tique et des VOCs, tous intrins\ue9quement dans des \ue9missions induites des herbivores

Use of human GH in elderly patients with accidental hip fracture

OBJECTIVE: To investigate whether early intervention with recombinant human growth hormone (hGH) after hip fracture improves functional recovery and long-term outcome. SUBJECTS AND METHODS: Functional recovery after hip fracture is often incomplete. The catabolic situation that develops after the hip fracture accident, and a state of malnutrition either pre-existing or developing after surgery, are main contributing factors for the poor clinical outcome. hGH has been used to promote anabolism in a variety of clinical catabolic situations. The study design was randomized, double-blind and placebo-controlled. A total of 111 patients older than 60 years with an accidental hip fracture (mean age 78.5+/-9.1 (s.d.) years) were randomized to receive either hGH (20 microg/kg per day) or placebo for a period of 6 weeks, starting within 24 h after the hip fracture accident. Thereafter patients were followed up for an additional period of 18 weeks. Efficacy was assessed by comparing the changes in the Barthel Index score of activities of daily living and in a patient's living situation between the hGH- and the placebo-treated subjects. RESULTS: Eighty-five (78.5%) patients completed the first 8 weeks of the study and 76 (68.5%) the entire study period of 24 weeks. When split according to age, a trend was found that for patients older than 75 years the changes in Barthel Index score from baseline were less in the hGH group than in the placebo group (-18.6+/-18 vs -28.1+/-26) at 6 weeks after surgery (P<0.075). There was an overall trend to a higher rate of return to the pre-fracture independent living situation in the hGH group than in the placebo group. Analysis by age revealed a significantly higher proportion of hGH- than placebo-treated patients returning to the pre-fracture living situation for subjects older than 75 years (93.8 vs 75.0%, P=0.034). hGH treatment increased IGF-I values to levels in the range of those of normal subjects of 50-60 years of age. CONCLUSIONS: A 6 week treatment with hGH (20 microg/kg per day) of otherwise healthy patients after an accidental hip fracture may be of benefit if given to subjects older than 75 years of age. The rate of return to the pre-fracture living situation in subjects of this age treated with hGH was significantly increased when compared with the placebo-treated group. The treatment intervention was well tolerated and no safety issues were recorded

The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

Enantiomeric selectivity in behavioural and electrophysiological responses of Aedes aegypti and Culex quinquefasciatus mosquitoes.

1-Octen-3-ol is a kairomone for many haematophagous insects including mosquitoes. Numerous studies have examined the effects of racemic 1-octen-3-ol; however, few studies have investigated the role of individual enantiomers in relation to mosquito attraction. In the present study, we investigated the behavioural and electrophysiological responses of two mosquito species, Aedes aegypti and Culex quinquefasciatus, to individual enantiomers and mixtures of 1-octen-3-ol, employing a laboratory Y-tube olfactometer and single sensillum recordings. The olfactory receptor neurons of both Ae. aegypti and Cx. quinquefasciatus had a significantly higher response to the (R)-1-octen-3-ol enantiomer compared to the (S)-1-octen-3-ol enantiomer at 10-9 g μl-1 to 10-6 g μl-1. Behaviourally, Ae. aegypti was more responsive to the (R)-1-octen-3-ol enantiomer, showing an increase in flight activity and relative attraction compared to Cx. quinquefasciatus. The (R)-1-octen-3-ol enantiomer caused an increase in activation for Cx. quinquefasciatus. However, the most notable effect was from an (R:S)-1-octen-3-ol mixture (84:16) that caused significantly more mosquitoes to sustain their flight and reach the capture chambers (demonstrated by a reduced non-sustained flight activity), suggesting that it may have a behaviourally excitatory effect. For Cx. quinquefasciatus, a reduced relative attraction response was also observed for all treatments containing the (R)-1-octen-3-ol enantiomer, either on its own or as part of a mixture, but not with the (S)-1-octen-3-ol enantiomer. This is the first time enantiomeric selectivity has been shown for Ae. aegypti using electrophysiology in vivo. The implications of these results for exploitation in mosquito traps are discussed

Achieving food and environmental security: new approaches to close the gap

IntroductionAchieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Unless 50% more food, 50% more energy and 30% more freshwater are available by 2030, a ‘perfect storm’ is envisaged where there would be simultaneous shortages of all of these on a global scale [1]. This becomes an even more ‘wicked problem’ when climate change and an expanding global population act in concert, making the challenge of achieving global food security even more complex and demanding.Food security ‘exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life’ [2, Plan of Action no. 1]. It is determined by four factors: (i) availability (from agricultural production and land-use or exchange); (ii) stability of supplies (e.g. seasonally and from year to year); (iii) access (dependent on financial means but also physical access and social factors); and (iv) biological utilization of food (e.g. nutritional diversity and food safety issues) [3]. It is estimated that almost one billion people face hunger through lack of macronutrients [4], and a further one billion lack sufficient micronutrients, leading to both negative health and development outcomes [5].Millennium development goal (MDG) number 1 (eradicate hunger and poverty) is effectively coupled to many of the other MDGs; it is imperative that we develop mechanisms to meet MDG 1 and other goals that are complementary and which do not oppose one another. For example, sustainable intensification (SI) of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has led historically to environmental degradation, reduced biodiversity and limitations to ecosystem services, with the greatest impacts falling upon the poor. Addressing MDGs in isolation can, therefore, be at the expense of others, and improved integration of actions is required. We must increase food security sustainably and in a climate change-resilient manner, while also reducing greenhouse gas emissions, alleviating poverty and conserving biodiversity [4–7]: perhaps the greatest challenge that we have ever faced.The relationship between food security outcomes and the environment is complex and multidimensional [8]. Food security is dependent not only on (non-provisioning) ecosystem services, but it is also one of the greatest drivers of the loss of ecosystem services. The pursuit of food security through increased agricultural production may include changes in land use, land cover, management practices and agricultural inputs, and it a key driver of landscape change [9].The concepts of planetary boundaries and ‘safe operating space’ have already had a significant influence on the international discourse about global sustainability [10]. Nine interlinked ecological boundaries have been defined at the planetary scale, and it is argued that society should remain within these if it is to avoid ‘disastrous consequences for humanity’. Three of these (biodiversity loss, climate change and nitrogen cycling) have all been exceeded, and all are linked to agricultural intensification. A recent and novel framework for considering this concept has been proposed by economists from Oxfam [11]. The ‘safe and just operating spaces’ (doughnut) idea argues for the need to live within the ‘space’ that lies beneath the planetary boundary, yet above the social floor of basic and just needs for food, energy and water security, and social goods such as education and healthcare.How do we deliver food security for all, without further exceeding planetary boundaries that have already been breached? Many of these social and just boundaries are linked to the MDGs and will undoubtedly be within the emerging sustainable development goals planned for post-2015. Science must play a central role in providing innovative solutions to these challenges, and this special issue of the Philosophical Transactions of the Royal Society B captures a Discussion Meeting (‘Achieving food and environmental security: new approaches to close the gap’) that took place at the Royal Society, in London between 3 and 4 December 2012, to explore some of avenues that science is currently pursuing. It invited prominent speakers to report on (i) the challenges that we face in achieving food and environmental security, (ii) research and extension in pursuit of sustainable production intensification, (iii) innovation for sustainable agriculture and (iv) using the ecosystem services framework for managing agricultural ecosystems.Following the London meeting, a workshop was held at the Kavli International Centre between 5 and 6 December 2012. Discussions at this meeting focused on reviewing the key issues, barriers and opportunities for science to contribute towards the new global agricultural systems that are needed to deliver food security. From this workshop, a statement ‘The Kavli Declaration: a vision for agriculture in 2050’ was developed. All of the attendees at the Kavli workshop have signed the declaration, which is presented in box 1

A bioassay for studying behavioural responses of the common bed bug, Cimex lectularius (Hemiptera: Cimicidae) to bed bug-derived volatiles.

The common bed bug, Cimex lectularius (Hemiptera: Cimicidae), has recently re-emerged in increasing numbers, distribution and intensity of infestation in many countries. Current control relies on the application of residual pesticides; but, due to the development of insecticide resistance, there is a need for new tools and techniques. Semiochemicals (behaviour and physiology modifying chemicals) could be exploited for management of bed bugs. However, in order to identify semiochemicals that can be utilised in monitoring or control, a suitable olfactometer is needed that enables the study of the responses of bed bugs to volatile chemicals. Previous studies have used olfactometers that do not separate olfactory responses from responses to physical contact. In this study, a still-air olfactometer was used to measure behavioural responses to different bed bug-derived volatiles presented in an odour pot. Bed bugs were significantly more likely to visit the area above the odour pot first, and more frequently, in the presence of volatiles from bed bug-exposed paper but not in the presence of volatiles from conspecific bed bugs. Bed bug activity was found to be dependent on the presence of the volatiles from bed bug-exposed paper, the time during the scotophase and the sex of the insect being tested. The still-air olfactometer could be used to test putative semiochemicals, which would allow an understanding of their behavioural role in bed bug ecology. Ultimately, this could lead to the identification of new semiochemical tools for bed bug monitoring and control