Insect Body Defence Reactions against Bee Venom: Do Adipokinetic Hormones Play a Role?

Bees originally developed their stinging apparatus and venom against members of their own species from other hives or against predatory insects. Nevertheless, the biological and biochemical response of arthropods to bee venom is not well studied. Thus, in this study, the physiological responses of a model insect species (American cockroach, Periplaneta americana) to honeybee venom were investigated. Bee venom toxins elicited severe stress (LD50 = 1.063 uL venom) resulting in a significant increase in adipokinetic hormones (AKHs) in the cockroach central nervous system and haemolymph. Venom treatment induced a large destruction of muscle cell ultrastructure, especially myofibrils and sarcomeres. Interestingly, co-application of venom with cockroach Peram-CAH-II AKH eliminated this effect. Envenomation modulated the levels of carbohydrates, lipids, and proteins in the haemolymph and the activity of digestive amylases, lipases, and proteases in the midgut. Bee venom significantly reduced vitellogenin levels in females. Dopamine and glutathione (GSH and GSSG) insignificantly increased after venom treatment. However, dopamine levels significantly increased after Peram-CAH-II application and after co-application with bee venom, while GSH and GSSG levels immediately increased after co-application. The results suggest a general reaction of the cockroach body to bee venom and at least a partial involvement of AKHs.

Defence and attack behaviour.

This chapter discusses the organization of behaviour in animals in the following aspects: defence and attack; defence and avoidance; agonistic reactivity; and defence reactions to humans by farm animals.

Induced resistance in wheat

During evolution, plants have developed a variety of chemical and physical defences to protect themselves from stressors. In addition to constitutive defences, plants possess inducible mechanisms that are activated in the presence of the pathogen. Also, plants are capable of enhancing their defensive level once they are properly stimulated with non-pathogenic organisms or chemical stimuli. This phenomenon is called induced resistance (IR) and it was widely reported in studies with dicotyledonous plants. However, mechanisms governing IR in monocots are still poorly investigated. Hence, the aim of this thesis was to study the efficacy of IR to control wheat diseases such leaf rust and Septoria tritici blotch. In this thesis histological and transcriptomic analysis were conducted in order to better understand mechanisms related to IR in monocots and more specifically in wheat plants. Successful use of beneficial rhizobacteria requires their presence and activity at the appropriate level without any harmful effect to host plant. In a first step, the interaction between Pseudomonas protegens CHA0 (CHA0) and wheat was assessed. Our results demonstrated that CHA0 did not affect wheat seed germination and was able to colonize and persist on wheat roots with a beneficial effect on plant growth. Once we showed the absence of side effects of CHA0 on wheat plants, in the second step, we evaluate efficacy of CHA0 or β-aminobutyric acid (BABA) to induce resistance against leaf rust caused by the biotroph Puccinia triticina in wheat. Our results confirmed the capacity of CHA0 to control leaf rust at the seedling stage. BABA showed dose-dependent reduction of leaf rust infection accompanied with plant growth repression at 20 mM. Balancing between protection and growth repression, a concentration of 15 mM was chosen as suitable dose for leaf rust control. Defence reactions such as callose deposition and H2O2 regeneration involved in the observed resistance were investigated. Both treatments reduced fungal penetration and haustoria formation of P. triticina with differences in timing and amplitude, leading to different levels of resistance to leaf rust. IR in wheat was accompanied with high deposition of callose and the accumulation of H2O2 during fungal infection, showing their importance in mechanisms involved in this resistance. To deeply clarify differences and similarities between CHA0- and BABA-IR at transcriptomic level, in the third step, the expression level of defence-related genes was analysed by RT-qPCR during IR induced by CHA0 and BABA against leaf rust. A correlation between induction of genes and P. triticina infection events was observed. A clear difference between the two induced responses is that BABA target more defence-related genes compared to CHA0 treatment. The last step was to evaluate the two mentioned elicitors (CHA0 and BABA), Pseudomonas chlororaphis PCL1391 and Benzothiadiazole (BTH) for their ability to induce resistance in wheat against the hemibiotrophic fungus Zymoseptoria tritici. Only BABA efficiently enhanced plant resistance to Z. tritici. In conclusion, exploiting IR might be a prominent strategy to control wheat disease. However, its effectiveness depends on the combination inducer/pathogen. Arguably, CHA0 bacteria and BABA induce similar defence reactions leading both to enhanced levels of resistance. However, only BABA enhanced defences against the hemibiotroph Z. tritici, suggesting that resistance of the plants react to the lifestyle of the pathogen and IR enhances does not involve necessarily all of them. More understanding is needed on both on capacity of the inducer to induce and the plant to become induced.

Study of melanin localization in the mature maleCalopteryx haemorrhoidalisdamselfly wings

DamselfliesCalopteryx haemorrhoidalisexhibiting black wings are found in the western Mediterranean, Algeria, France, Italy, Spain and Monaco. Wing pigmentation is caused by the presence of melanin, which is involved in physiological processes including defence reactions, wound healing and sclerotization of the insect. Despite the important physiological roles of melanin, the presence and colour variation among males and females of theC. haemorrhoidalisspecies and the localization of the pigment within the wing membrane remain poorly understood. In this study, infrared (IR) microspectroscopy, coupled with the highly collimated synchrotron IR beam, was employed in order to identify the distribution of the pigments in the wings at a high spatial resolution. It was found that the melanin is localized in the procuticle of theC. haemorrhoidalisdamselfly wings, distributed homogeneously within this layer, and not associated with the lipids of the epicuticle.

Russian-American Relations in the Post-Cold War World

Why did the Russian take-over of Crimea come as a surprise to so many observers in the academic practitioner and global-citizen arenas? The answer presented in this book is a complex one, rooted in late-Cold War dualities but also in the variegated policy patterns of the two powers after 1991. This book highlights the key developmental stages in the evolution of the Russian-American relationship in the post-Cold War world. The 2014 crisis was provoked by conflicting perspectives over the Balkan Wars of the 1990s, the expansion of NATO to include former communist allies of Russia as well as three of its former republics, the American decision to invade Iraq in 2003, and the Russian move to invade Georgia in 2008. This book uses a number of key theories in political science to create a framework for analysis and to outline policy options for the future. It is vital that the attentive public confront the questions raised in these pages in order to control the reflexive and knee-jerk reactions to all points of conflict that emerge on a regular basis between America and Russia.Key topics include struggles over the Balkans, the expansion of NATO, the challenges posed by terrorism to both nations, wars fought by both powers in the first decade of the twenty-first century, conflict over missile defence, reactions to post-2011 turmoil in the Middle East, and the mutual interest in establishing priorities in Asia.

Defence reactions of mature Norway spruce (Picea abies) before and after inoculation of the blue-stain fungus Endoconidiophora polonica in a drought stress experiment

We performed an inoculation experiment using the blue-stain fungus Endoconidiophora polonica at the Rosalia Roof study site, which was set up to study drought effects on Norway spruce susceptibility to attacks by the European spruce bark beetle Ips typographus. Tree resistance parameters such as resin flow rate and extent of hypersensitive wound reaction in the phloem were investigated prior to and after fungal infection. Sample trees with different drought treatments (trees fully covered or semi-covered by roofs, control trees) were inoculated with E. polonica in July 2014. In order to check for areas of phloem necrosis, the outer bark around the inoculation holes was scratched off 6 weeks later. We recorded the amount of resin exudation within 12 hours overnight in August and September 2013 and 2014. Although wound reaction zones did not differ in size between tree collectives of the various treatments, fully covered trees tended to exhibit larger necrotic areas compared to control trees. The least water supplied trees showed lowest resin flow rates prior to fungal inoculation, but were the only group to show significantly enhanced resin flow five weeks after the evaluation of defence reactions. Our results agree with earlier findings that wounding and few fungal inoculations can increase tree resistance in the medium term given not too severe water stress. Further investigations will clarify how water stress affects the availability of non-structural carbohydrates for secondary metabolism, when depletion of resources eventually occurs, and at which point trees are most susceptible to bark beetle attack.

INCREASED VIRAL-RESISTANCE OF YELLOW LUPINE UNDER THE ACTION OF MICROBIAL PREPARATIONS AND PHYSIOLOGICALLY ACTIVE SUBSTANCES

The influence of microbial preparations and physiologically active substances on the reproduction bean yellow mosaic virus in yellow lupine plants has been investigated. It was established that the action of microbial preparations on the limitation of the viral infection development is explained by the influence of exogenous physiologically active substances, which are contained in preparations and produced by the microorganisms introduced in agrocenosis, on the forming of endogenous phytohormone pool. Therefore, it optimizes a number of physiological processes of the plants and activates their defence reactions.