FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / PeÃonhas de Hymenoptera, particularmente das famÃlias Apidae (abelhas) e Vespidae (vespas), sÃo uma rica fonte de peptÃdeos e proteÃnas com atividades biolÃgicas. A espÃcie Polybia Paulista à uma vespa social neotropical muito agressiva e endÃmica no Sudeste do Brasil. O objetivo deste trabalho foi estudar os efeitos renais e vasculares induzidos pelo veneno da Polybia paulista (VPp). Foram utilizados ratos (n = 4) machos Wistar pesando entre 250 e 300g, cujos rins foram isolados e perfundidos com SoluÃÃo de Krebs-Henseleit modificada contendo 6g% de albumina bovina previamente dialisada. A menor concentraÃÃo (1Âg/mL) nÃo apresentou efeito nos parÃmetros avaliados. PorÃm, a concentraÃÃo de 3Âg/mL produziu um aumentou na pressÃo de perfusÃo renal (PP), na resistÃncia vascular renal (RVR), no fluxo urinÃrio (FU) e no ritmo de filtraÃÃo glomerular (RFG). Foi tambÃm observada uma reduÃÃo aos 60â no percentual de transporte tubular de sÃdio (% TNa+). Na avaliaÃÃo histolÃgica do rim perfundido com VPp foi observado depÃsito de proteÃnas nos tÃbulos renais e nos espaÃos urinÃrios, bem como regiÃes focais de necrose/apoptose. A citotoxidade do veneno da Polybia paulista em cultura de cÃlulas MDCK foi analisada atravÃs do ensaio colorimÃtrico com sal de tetrazolium (MTT). O veneno promoveu um efeito citotÃxico dependente de concentraÃÃo com um valor de IC50 de 25.81Âg/mL. TambÃm foram mensurados os nÃveis de lactato desidrogenase (LDH) e observado um aumento significativo nas maiores concentraÃÃes estudadas. No estudo em leito mesentÃrico a pressÃo de perfusÃo foi mensurada atravÃs de um transdutor de pressÃo. O efeito vascular do VPp (3Âg/mL) nÃo alterou a pressÃo basal, na concentraÃÃo de 10Âg/mL, foi observado um aumento pressÃrico discreto e na concentraÃÃo de 100 Âg/mL, foi observado um acentuado aumento na pressÃo de perfusÃo basal. O efeito vasoconstritor observado no estudo renal e em leito mesentÃrico, tambÃm foi demonstrado no protocolo de anel de aorta, sendo observado de maneira concentraÃÃo dependente, um aumento do tÃnus basal apÃs a infusÃo do VPp. Em conclusÃo, o VPp causou nefrotoxidade, sugestivo de uma aÃÃo direta com morte celular em cÃlulas do tÃbulo renal por necrose. O efeito vascular contrÃtil que envolve influxo de cÃlcio atravÃs de canais operados por voltagem, provavelmente à mediado pela ativaÃÃo de receptores alfa adrenÃgicos.

Male fig wasps (Hymenoptera: Chalcidoidea) exhibit a fascinating range of morphology and behaviour. A cluster analysis, based on descriptions of the males of several hundred species, distinguished six major morphological groups. Behaviourial observations suggest that male morphology is related to the levels of inter-male aggression. Three behaviourial groupings were identified. Fighting species generally mated in the fig cavity, pacifist species mated in the females' galls or outside the figs. Mating sites are thus the primary determinants of male morphology and behaviour. In fighting species males were larger than their females, whereas pacifists and aggressors were equal in size or smaller than conspecific females. The large males in fighting fig wasps appear to be a consequence of sexual selection because larger males tended to win fights. Within a species there were no differences in the size of the galls that produced males and females, even in species where sexual size differences were present, suggesting that there is a heritable component to wasp size. No alternative advantages for smaller males were detected. Although fights were sometimes fatal, damage was not always a consequence of fighting behaviour and was recorded in both fighting and pacifist species. Sex ratios in several species were more female biased at higher population densities. Sex ratios of species with 'internally' ovipositing species were heavily female biased, but approached 1:1 in more outbred species with 'externally' ovipositing females. Levels of matedness, among females ranged from 73% to 99%. No evidence for sperm exhaustion was obtained. Species of Philotrypesis with both winged and flightless males were present only in southern African Ficus species from subsections Platyphyllae and Chlamydodorae. No species had only winged males. The flightless males of some Philotrypesis species were themselves polymorphic. In one polymorphic Philotrypesis species, winged males were found to be rare at high densities, but common at low densities. Digitata and religiosa males of Otitesella differed in coloration, size and behaviour. Digitata males were aggressors while religiosa males were fighters. Digitata males escaped from the figs whereas religiosa males remained inside the figs, perhaps because only digitata males were attracted to Light. Proportionally more digitata than religiosa males were present in low density populations and females were found to respond differently to the two morphs.

The Sycoecinae are a distinct and well-defined subfamily of old world fig wasps (Agaonidae, Chalcidoidea 1 Hymenoptera) , exclusively associated with the figs of Ficus species (Moraceae). The most likely sister group of the Sycoecinae was determined to be the Sycoryctini (Sycoryctinae) based largely on synapomorphies of the underside of the head. 67 sycoecine species and 3 subspecies were recognised and included in a phylogenetic analysis of the subfamily. This analysis clearly delimited six genera (four African and two extra-African), although the phylogenetic relationships between the genera were not strongly supported and remain flexible. Comparisons of the phylogeny of the Sycoecinae with the classifications of the Agaoninae and their host fig trees (Ficus, Moraceae) suggest a degree of cospeciation sensu lato. Numerous homoplasies were detected within the Sycoecinae, some of which were shared with another group of fig wasps that also enter the fig to oviposit, the Agaoninae. The anatomy of the figs apparently provides strong selection pressures that have resulted in both parallelisms and convergences within and between the two subfamilies. Among the 67 species and 3 subspecies that were recognised, 43 species and 2 subspecies are described as new. The males of three previously recognised species are also described for the first time. One generic and two specific synonyms are established together with five new combinations. Keys are provided to the genera and species, for both sexes.

Yes / Coronin7 (CRN7) stabilizes F-actin and is a regulator of processes associated with the actin cytoskeleton. Its loss leads to defects in phagocytosis, motility and development. It harbors a CRIB (Cdc42- and Rac-interactive binding) domain in each of its WD repeat domains which bind to Rac GTPases preferably in their GDP-loaded forms. Expression of wild type CRN7 in CRN7 deficient cells rescued these defects, whereas proteins with mutations in the CRIB motifs which were associated with altered Rac binding were effective to varying degrees. The presence of one functional CRIB was sufficient to reestablish phagocytosis, cell motility and development. Furthermore, by molecular modeling and mutational analysis we identified the contact regions between CRN7 and the GTPases. We also identified WASP, SCAR and PAKa as downstream effectors in phagocytosis, development and cell surface adhesion, respectively, since ectopic expression rescued these functions.

Altruism in its extreme form is seen in social insects where most individuals give up their own reproduction and work to rear the offspring of their queen. The origin and evolution of such sterile worker castes remains a major unsolved problem in evolutionary biology. Primitively eusocial polistine wasps are an attractive model system for investigating this phenomenon. Ropalidia marginata (Lep.) (Hymenoptera: Vespidae) is one such tropical primitively eusocial wasp, in which new nests are initiated either by a single foundress or by a group of female wasps. Worker behaviour in Ropalidia marginata cannot be satisfactorily explained by the haplodiploidy hypothesis due to the existence of polyandry and serial polygyny which reduce intra-colony genetic relatedness to levels lower than the value expected between a solitary foundress and her offspring. Besides, wasps appear to move frequently between newly initiated nests, perhaps further reducing intracolony genetic relatedness. To study social organization and examine the possibility of kin recognition and task specialization under conditions of low intra-colony relatedness, genetically mixed colonies were created by introducing alien one-day old wasps onto recipient nests. As a first step I have tried to determine the factors that influence the acceptance of foreign wasps onto established colonies. I have introduced wasps between 1 to 20 days of age from donor colonies located at least 10 km away onto 12 different recipient colonies, observed these wasps for a period of 10 hours and later dissected them to examine their ovarian condition. Observations were carried out in the blind i.e. the observer was unaware of the identity of the wasps. Wasps upto 6 days of age were accepted by the alien nests. Older wasps may have been rejected because their relatively better ovarian condition may have been perceived as a reproductive threat to the recipient nest. Alternatively, younger wasps may have been accepted because they may be more easily moulded to the desired roles or due to some other correlate of age per se independent of ovarian condition. Although ovarian condition appeared to influence the probability of acceptance, it was not statistically significant in the presence of age in multiple regression models, making a favourable case for the 'ease of moulding hypothesis' or 'age per se hypothesis' over the 'reproductive threat hypothesis'. In any case these findings gave me a method to create genetically mixed colonies. On 12 different nests Ropalidia marginata, I similarly introduced one-day old wasps and thus created genetically mixed colonies. Such an introduction simulates the eclosion of distantly related individuals which is quite common on nests of R. marginata due to the presence of serial polygyny. About 7 such wasps were introduced per colony and the introductions were so arranged as to matched with natural eclosions on the recipient nest. After 7 days following the last introduction, colonies were observed for 20 hours each. Alien wasps became well integrated and performed most of the behaviours and tasks shown by the natal wasps. There was no evidence of kin recognition or task specialization between natal and introduced wasps. The introduced wasps also sometimes became replacement queens. In an attempt to test the costs in terms of brood rearing efficiency, of living in such genetically variable groups, I created kin and non-kin pairs of wasps in plastic containers. They were provided with ad libitum food, water and building material. The nests initiated were monitored till an adult offspring eclosed. There were no detectable differences in either the productivities or the developmental periods of immature stages in the kin and nonkin pairs suggesting that there is no apparent cost of living with unrelated or distantly related individuals. To compare the extent of cooperation between the two wasps in kin and non-kin pairs, I conducted behavioural observations on 12 pairs each of kin and nonkin wasps. I found no difference in the rates at which the non-egg layers brought food and pulp, fed larvae and built the nest in the kin and nonkin pairs suggesting that cooperative nest building and brood rearing was common to the kin as well as non-kin pairs. The results reported here strengthen the idea that factors other than genetic relatedness must play a prominent role in the maintenance of worker behaviour in Ropalidia marginata.

Division of labour is a hallmark of eusocial insects and is believed to be a major factor in their evolutionary success and ecological dominance. Division of labour can be of two kinds – reproductive division of labour where a minority of individuals are egg-layers or reproductives (kings and queens) and the majority are workers or non-reproductives involved mostly in non-reproductive tasks of the colony (workers). Kings/queens and workers are often referred to as separate castes within a social insect colony. There may be further non-reproductive division of labour within the worker caste, based on their morphology or age. In primitively eusocial organisms there is no morphological caste differentiation between the egg-layers and non-egg-layers resulting in greater flexibility in the social roles of individuals within a colony. This creates a very interesting scenario to study the mechanism of division of labour. Moreover our knowledge regarding division of labour especially non-reproductive division of labour is very limited for primitively eusocial organisms. In this thesis I have studied division of labour in a primitively eusocial wasp species, Ropalidia cyathiformis. R. cyathiformis is a tropical primitively eusocial wasp with a perennial nesting cycle. This species usually has a single dominant queen and several workers. I studied reproductive and non-reproductive division of labour, as well as the role of dominance behaviour in the regulation of both reproductive and non-reproductive activities. In addition to this I have also compared my findings with what is already known in the well-studied congeneric species, Ropalidia marginata. Reproductive division of labour To understand reproductive division of labour in R. cyathiformis, I studied queen succession, by experimentally removing the queen. When the queen was removed, one and only one individual increased her aggression and became the new queen of the colony, unchallenged by any other worker. Such a successor was referred to as a potential queen (PQ) until she lays her first egg. By removing the queen and successive PQs, I showed that there is not just one successor but a strict reproductive hierarchy of up to 3 PQs, who succeed the queen one after the other. Of many variables tested, I found that only the frequency of dominance behaviour was a significant predictor of whether or not an individual is part of the reproductive hierarchy and also of her position in the hierarchy. Dominance behaviour however does not perfectly predict the position of an individual in the reproductive hierarchy because I showed that an average of three more dominant individuals, are bypassed when an individual becomes the next queen or PQ. This was in contrast to the reproductive hierarchy in the congeneric Ropalidia marginata, where age rather than dominance behaviour was a predictor (though imperfect once again) of an individual’s position in the queue. Taken together, my results suggest that (a) these two sister species have evolved two rather different mechanisms of reproductive caste differentiation, (b) that neither of them strictly conform either to the so called “temperate” or “tropical” patterns of queen succession seen in most other species studied so far. Non-reproductive division of labour As mentioned above, non-reproductive division of labour in eusocial insects is based on either the morphology or the age of the individuals within the colony. Since there is no morphological castes present in primitively eusocial species, I focussed on the effect of age on division of labour in R. cyathiformis. I analysed the frequency as well as the probability of performance of four functionally significant tasks namely, two intranidal tasks – feed larva and build as well as two extranidal tasks – bring food and bring building material. I measured absolute as well as relative ages of the wasps. I found that there is an effect of age on division of labour. Age of first performance of the tasks indicated a clear sequence for the initiation of the tasks with intranidal tasks initiated before extranidal tasks. The frequency of task performance (FTP) and absolute age better explained the variation in the data as compared to probability of task performance (PTP) and relative age. This was in contrast to the pattern of age polyethism found in the congeneric species, Ropalidia marginata, where PTP and relative age better explains the variation in the data. This suggests a more flexible age-dependant division of labour in R. marginata and a rigid age polyethism in R cyathiformis. In addition I found that there was no clear-cut partitioning of the intranidal and extranidal tasks in R. cyathiformis, whereas in R. marginata, it has been shown that the frequency of the intranidal tasks decline with age while that of extranidal tasks increase with age. When taken together, I could say that R. marginata has a more strongly developed age polyethism as compared to R. cyathiformis. This study also shows an evolution of age polyethism with R. cyathiformis behaving more like a typical primitively eusocial species while R. marginata more like a highly eusocial species. Role of dominance behaviour in reproductive and non-reproductive division of labour When reproductive regulation in R. cyathiformis was studied, I found that queens of this species target the potential queen (PQ) by showing the maximum frequency per hour of dominance behaviour to the PQ. The PQs on the other hand seem to show the maximum amount of dominance behaviour towards newborns (wasps of age class 0-5 days). Queens seem to regulate only reproductive activities and not the non-reproductive activities as there was no difference in the frequency of both feed larva and bring food behaviour in the colony even after removing the queen. It also appears that dominance behaviour is not used to signal hunger or regulate foraging as there was no significant correlation between the frequency per hour of bring food behaviour and dominance behaviour received. Moreover the foragers do not receive more aggression than other wasps in the colony from either the queen, PQ or intranidal workers. I also found a significant positive correlation between the frequency per hour of bring food behaviour and feed larva behaviour implying that foraging might be a self-regulated process in this species. Hence in R. cyathiformis it appears that dominance behaviour is used only for regulation of reproductive division of labour and not for regulation of non-reproductive division of labour. This was in contrast to the congeneric species, R. marginata where the opposite has been shown to be true; the reproductive regulation is achieved by means of pheromones produced by the queen and work organisation follows a decentralised self-organised manner with intranidal workers signalling or regulating foragers using dominance behaviour. Comparison with Ropalidia marginata Ropalidia cyathiformis and Ropalidia marginata, although congeneric species co-existing in the same habitat, have evolved very different mechanisms for division of labour. R. marginata exhibiting features such as 1) presence of a docile queen 2) reproductive regulation by means of pheromones 3) strongly developed and flexible age polyethism 4) decentralised work organisation seem to be more similar to a highly eusocial organism than to a primitively eusocial species. R. cyathiformis on the other hand seems to exhibit several features typical to a primitively eusocial species, such as 1) presence of a dominant queen 2) reproductive regulation by physical means 3) relatively weak and rigid age polyethism 4) self-regulatory method of work organisation. Hence the two species seem to be at two different stages of evolution with R. marginata appearing to be intermediate between primitively and highly eusocial species.

Made available in DSpace on 2014-06-11T19:22:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-09Bitstream added on 2014-06-13T19:47:18Z : No. of bitstreams: 1 aguiar_mb_me_sjrp.pdf: 1374388 bytes, checksum: 3f0881d7dfbe0cb771b8a1ffb4572604 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os venenos de vespas socias são ricos em peptídeos biologicamente ativos que causam alguns males ao ser humano como: dores prolongadas, edema, eritema, reações alérgicas e sistêmicas. Possuem em sua composição vários tipos de aminas biogênicas, peptídeos e proteínas. Dentre eles, o que chama mais atenção na atividade farmacológica do veneno são os peptídeos policatiônicos. São diversas as atividades desses peptídeos como: neurotoxicidade, hemólise, liberação de histamina de mastócitos e antibatericida. Neste trabalho, foram estudados peptídeos catiônicos da família Polybine, sintetizados pelo Departamento de Biologia, Unesp, Rio Claro-SP. Os peptídeos Polybine I e II foram sintetizados na forma acetilada e não-acetilada para o estudo detalhado da sua estrutura. Com este objetivo, utilizamos as técnicas de Dicroísmo Circular (CD), para uma análise da estrutura secundária da amostra e espectroscopia de Ressonância Magnética Nuclear (RMN) para o estudo da estrutura tridimensional do peptídeo em solução. / Social wasp venoms are rich of biologically active peptides that may cause some malady to human such as prolonged pains, edema, erythema, allergies and systemic reactions. They have, in its composition, many kinds of biogenic amines, series of polycationics peptides and proteins. Among them, the most interesting thing in pharmacological activity are the polycationics peptides. These peptides show several activities like neurotoxicity, hemolytic activity, histamine releasing activity and antimicrobial activity. In this project, cationic peptides of the Polybine family synthesized by the Department of Biology, CEIS/IBRC, UNESP, Rio Claro, SP were studied. The cationic peptides Polybine I and II were synthesized in acetylad and non-acetylad forms to the detailed study of the structure. This way, CD spectroscopy were performed to analyze secondary structure of the sample and, to analyze treedimension structure, NMR spectroscopy were used.

WASP-18 hosts a massive, very close-in Jupiter-like planet. Despite its young age (< 1 Gyr), the star presents an anomalously low stellar activity level: the measured log R'(HK) activity parameter lies slightly below the basal level; there is no significant time-variability in the log R'(HK) value; there is no detection of the star in the X-rays. We present results of far-UV observations of WASP-18 obtained with COS on board of Hubble Space Telescope aimed at explaining this anomaly. From the star's spectral energy distribution, we infer the extinction (E(B-V) approximate to 0.01 mag) and then the interstellar medium (ISM) column density for a number of ions, concluding that ISM absorption is not the origin of the anomaly. We measure the flux of the four stellar emission features detected in the COS spectrum (C II, C III, C IV, Si IV). Comparing the C II/C IV flux ratio measured for WASP-18 with that derived from spectra of nearby stars with known age, we see that the far-UV spectrum of WASP-18 resembles that of old (> 5 Gyr), inactive stars, in stark contrast with its young age. We conclude that WASP-18 has an intrinsically low activity level, possibly caused by star-planet tidal interaction, as suggested by previous studies. Re-scaling the solar irradiance reference spectrum to match the flux of the Si IV line, yields an XUV integrated flux at the planet orbit of 10.2 erg s(-1) cm(-2). We employ the rescaled XUV solar fluxes to models of the planetary upper atmosphere, deriving an extremely low thermal mass-loss rate of 10(-20) M-J Gyr(-1). For such high-mass planets, thermal escape is not energy limited, but driven by Jeans escape.

Orientador: Stephen Hyslop / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-18T04:48:28Z (GMT). No. of bitstreams: 1 Silva_DelanoAnibalda_D.pdf: 1969731 bytes, checksum: de221836aebacda27e28c520b97a53e9 (MD5) Previous issue date: 2011 / Resumo: As peçonhas de himenópteros contêm diversas toxinas que podem causar hemólise, cardiotoxicidade e insuficiência renal, além de reação de hipersensibilidade. Adicionalmente, algumas vespas e formigas utilizam sua peçonha para imobilizar ou matar a presa. Neste estudo analisamos as atividades fosfolipásica (PLA2) e hemolítica bem como a atividade biológica sobre íleo e átrio isolados de rato, e sobre coração semi-isolado de barata, das peçonhas de formiga (Paraponera clavata) e vespa (Polistes lanio lanio). A eletroforese das peçonhas (SDS-PAGE) revelou a presença de componentes com massas moleculares de ~22 kDa a 100 kDa em P. clavata e de 19 a 119 kDa em P. l. lanio. Já a cromatografia por gel filtração resultou em cinco picos principais para a peçonha de P. clavata e seis para a de P. l. lanio. A peçonha de P. clavata possuiu atividades PLA2 e hemolítica moderadas, que foram abolidas pelo aquecimento (100ºC, 20 min). A peçonha de P. clavata (0,1-3 ?g/ml) contraiu íleo isolado de rato, cujo efeito foi dessensibilizante e resistente ao aquecimento da peçonha. Esta atividade contraturante foi localizada no primeiro pico do perfil de eluição da cromatografia por gel filtração. Em átrio isolado de rato a peçonha de P. clavata (0,125-10 ?g/ml) causou contratura, resultando em diminuição da força contrátil e redução na freqüência atrial com aumento na liberação de creatinoquinase-MB (CK-MB) tecidual. O aquecimento da peçonha não aboliu esta ação atrial. A análise histopatológica mostrou necrose dos cardiomiócitos que não foi afetada pelo aquecimento. Dos picos obtidos por gel filtração, o pico 1 reproduziu a contratura causada pela peçonha enquanto o pico 3 aumentou a contratilidade atrial. Em coração semi-isolado de barata, a peçonha de P. clavata (1-100 ?g) causou bradicardia. Conclui-se que a peçonha de P. clavata: (1) possui atividades PLA2 e hemolítica que são termolábeis, (2) causa bradicardia em coração semi-isolado de barata, e (3) provoca contração em íleo isolado e contratura em átrio direito de rato. Ao contrário de P. clavata, a peçonha de P. l. lanio (0,3-100 ?g/ml) mostrou altas atividades PLA2 e hemolítica que também foram abolidas pelo aquecimento (100ºC, 20 min). A peçonha contraiu íleo isolado de rato, e causou inotropismo negativo em átrio direito isolado de rato, sem afetar o cronotropismo; não houve contratura da linha basal. A peçonha causou forte bradicardia em coração semi-isolado de barata que não foi abolido pelo aquecimento (100ºC, 20 min). Este cronotropismo negativo foi mediado por uma fração da peçonha de P. l. lanio enriquecida em componentes de baixa massa molecular (<5 kDa, obtida através da ultrafiltração). A cromatografia desta fração em HPLC de fase reversa resultou em seis picos, dos quais apenas o pico 4 causou bradicardia em coração semi-isolado de barata. A bradicardia foi bloqueada pela glibenclamida, sugerindo o envolvimento de canais de K+ dependentes de ATP neste fenômeno. A análise do pico ativo por espectrometria de massas indicou a presença de peptídeos. Conclui-se que a peçonha de P. l. lanio: (1) tem alta atividade fosfolipásica e hemolítica (ambas termolábeis), (2) provoca contração de íleo e inotropismo negativo em átrio direito de rato e (3) exerce forte cronotropismo negativo em coração semi-isolado de barata mediado pela ativação de canais de potássio dependentes de ATP / Abstract: Hymenoptera venoms contain toxins that can cause hemolysis, renal failure, cardiotoxicity and hypersensitivity in humans. Additionally, some wasps and ants use their venom to immobilize or kill prey. In this study, we analyzed the phospholipase (PLA2) and hemolytic activities of ant (Paraponera clavata) and wasp (Polistes lanio lanio) venoms, and their action on rat isolated ileum and right atrium and cockroach semi-isolated heart. Electrophoresis (SDS-PAGE) showed that the venoms of P. clavata and P. l. lanio contained components with molecular masses of ~20-100 kDa and 19-119 kDa, respectively. Gel filtration chromatography resulted in five major peaks for P. clavata venom and six for P. l. lanio. Paraponera clavata venom had moderate phospholipase and hemolytic activities that were abolished by heating (100ºC, 20 min). This venom (0.1-3 ?g/ml) contracted rat isolated ileum, with a desensitizing effect, and heating the venom did not abolish this activity, which was located in the first peak of the gel filtration elution profile. In isolated atria, the venom (0.125-10 ?g/ml) caused muscle contraction that resulted in decreased contractile force and a reduction in atrial rate, with an increase in creatine kinase-MB (CK-MB) release; this atrial action was not abolished by heating. Histopathological analysis revealed myonecrosis that was also unaffected by heating. Of the peaks obtained by gel filtration, peak 1 reproduced the contraction observed with the venom whereas peak 3 caused a sustained increase in atrial contractility. The venom (1-100 ?g) caused bradycardia in cockroach semi-isolated hearts. These results show that P. clavata venom: (1) has PLA2 and hemolytic activities that are thermolabile, (2) causes bradycardia in cockroach semi-isolated hearts, and (3) contracts rat isolated ileum and causes contracture of rat right atria. In contrast to P. clavata, P. l. lanio venom (0.3-100 ?g/ml) showed high PLA2 and hemolytic activities that were also abolished by heating (100°C, 20 min). Polistes l. lanio venom contracted rat isolated ileum and produced negative inotropism in isolated rat right atria; there was no effect on the chronotropic response or on the baseline tension, i.e., no muscle contracture. The venom caused marked bradycardia in coackroach semi-isolated hearts that was unaffected by heating. This bradycardia was mediated by a low-molecular mass fraction of the venom (<5 kDa, obtained by ultrafiltration). RP-HPLC of this fraction resulted in six peaks, of which only the fourth caused bradycardia in cockroach semi-isolated hearts. This bradycardia was blocked by glibenclamide, suggesting the involvement of ATP-dependent K+ channel activation. Mass spectrometry of the active peak indicated the presence of peptides. These results indicate that P. l. lanio venom: (1) has high PLA2 and hemolytic activities that are thermolabile, (2) contracts rat isolated ileum and reduces the contractile force of isolated right atria, and (3) causes marked bradycardia in cockroach semi-isolated heart via the activation of ATP-dependent K+ channels / Doutorado / Farmacologia / Doutor em Farmacologia

This thesis has looked at the proximate mechanisms by which eusociality is maintained in colonies of the primitively eusocial wasp Ropalidia marginata. Unlike other typical primitively eusocial species, the R, marginata queen is remarkably docile and non-interactive and hence cannot possibly use aggression to maintain her status. Recent evidence hints at pheromonal queen signalling through the Dufour’s gland. Hence, queen-worker difference in Dufour’s gland composition has been studied in details. Queens and workers differ with respect to overall composition of Dufour’s glands, categories of compounds, and individual compounds as well. The Dufour’s gland compounds may be having a bouquet effect in queen signalling, with individual compounds being less important than the overall composition. The queen pheromone also appears to be an honest signal of fertility, as compounds that differ consistently between queens and workers are correlated with ovarian development of queens, and solitary foundresses and potential queens, who are intermediate between queens and workers in ovarian development, are intermediate in their Dufour’s gland profile as well. When the queen is removed from a colony, one of the workers (potential queen, PQ) shows high aggression, and if the queen is not returned, goes on to become the next queen of the colony. The aggression of PQ comes down as a function of time since queen removal, and correlated with this, the ovaries of PQ increase. Dufour’s gland profile of PQ is similar to workers immediately after queen removal, but comes closer to queens with passage of time. This hints at an interesting transition in maintenance of eusociality from “queen control” by aggression to “queen signal” by pheromone during the queen establishment phase. It has generally been assumed that one set of chemicals can carry multiple information, namely queen signal and colony signal. Initial statistical analysis of chemical composition data showed that perhaps both caste and colony signals can be conveyed by the Dufour’s gland compounds, but detailed analysis cast some doubt on this, as the Dufour’s gland compounds could not be separated into non-overlapping subsets with respect to importance in caste and colony discrimination. A bioassay showed that the wasps do not make colony discrimination from Dufour’s gland compounds. This suggests that the ability to statistically differentiate groups of organisms from their chemical profiles does not guarantee similar discrimination by the organisms themselves, emphasising the need for bioassays to resolve such issues.