Magnetic nanoparticles in the body parts of Polistes versicolor and Polybia paulista wasps are biomineralized: evidence from magnetization measurements and ferromagnetic resonance spectroscopy.

The detection of the geomagnetic field by animals to use as a cue in homing and migration is known as magnetoreception. The ferromagnetic hypothesis explains magnetoreception assuming that magnetic nanoparticles in cellular structures are used as magnetic field transducers. Considering magnetoreception in social insects, the most studied has been the honeybee Apis mellifera and only in two wasp species (Vespa orientalis and Polybia paulista) have been shown a magnetosensitive behavior. In the present report the body parts (abdomen, head and antennae) of Polistes versicolor and Polybia paulista wasps were studied aiming to find biomineralized magnetic nanoparticles, using magnetometry measurements and ferromagnetic resonance spectroscopy. The magnetometry measurements show the presence of magnetic nanoparticles in all body parts, being characterized as mixtures of superparamagnetic, single domain and pseudo-single domain nanoparticles. From the ferromagnetic resonance spectra were obtained the asymmetry ratio A and the effective g factor geff, and those parameters are consistent with the presence of biomineralized magnetic nanoparticles in both wasps. In the case of Polybia paulista, the magnetic nanoparticles can be associated with some sort of magnetosensor once this wasp is magnetosensitive. For Polistes versicolor, the results indicate that this wasp can be magnetosensitive as Polybia paulista once their magnetic nanoparticles are biomineralized in the body. Behavioral studies with Polistes versicolor wasps deserve to be performed.

Proteomic analysis of the venom of the social wasp Apoica pallens (Hymenoptera: Vespidae)

ABSTRACT Wasps are a diverse group of insects that possess a sting apparatus associated with a venom gland, which is used for predation and colony defense. The biochemistry of Hymenoptera venom has been evaluated in relation to allergy and immunology, and proteomics has been shown to be a powerful tool for the identification of compounds with pharmacological potential. Data on wasps venom the of genus Apoica are scarce, so the objective of the present work was to identify the venom proteins of the eusocial wasp Apoica pallens, as a first step towards further investigation of applied uses of the venom and its protein constituents. The venom proteins were separated by two-dimensional gel electrophoresis, followed by MALDI-TOF/TOF mass spectrometry. A total of 259 spots were detected, with molecular weights from 4.9 to 141 kDa. Thirty of these proteins were identified and classified into eight functional categories: allergen, enzyme, metabolism, structural, environmental response, proteoglycan, active in DNA and RNA, and unknown function. Due to the few available proteomic data for wasp venom, many proteins could not be identified, which makes studies with proteomic analysis of Hymenoptera venom even more important.

Influence of temperature on survival and cuticular chemical profile of social wasps.

The cuticle of social insects is a barrier against desiccation and a channel for chemical communication, two characteristics fundamental to the success of this group. The compounds present in the cuticle interact dynamically in order to achieve a balance between these two functions. Thus, viscosity correlates with waterproofing, whereas fluidity correlates with effective communication. Temperature variation can cause the cuticular hydrocarbon (CHC) layer of the cuticle to change in order to maintain body homeostasis. Thus, in this study, we tested the hypothesis that wasps with different body sizes and nest types will differ in their tolerance to temperature variation and ability to respond by changing cuticular chemical composition. To test this hypothesis, workers of three species of social wasps with different body sizes and nests, both with or without envelope, were subjected to different temperatures under controlled conditions. Cuticular compounds were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Results show that tolerance to temperature variation is not directly related to either wasp size or nesting type. An increase in the percentage of linear alkanes and a decrease in the percentage of branched alkanes were correlated with increased temperature. Thus, instead of either body size or nest type, tolerance to temperature variation seems to be mediated by the changing chemical composition of the cuticle.

Observation of intra- and interspecific differences in the nest chemical profiles of social wasps (Hymenoptera: Polistinae) using infrared photoacoustic spectroscopy.

The aim of this study was to explore whether the nest chemical profile (NCP) can be used to determine intra- and interspecific differences in social wasps of the subfamily Polistinae. For this purpose, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to directly analyze small pieces of nest as well as the gasters of females. An advantage of the methodology was that no sample preparation was required. FTIR-PAS combined with multivariate discriminant analyzes was used, to the best of our knowledge for the first time, to evaluate the NCPs of six species of polistine wasps, observing the influence of the nesting environment and investigating the relationships among the nest and female cuticular chemical profiles. The results revealed significant inter-species differences among the NCPs, as well as strong correlations with the environments in which the nests were located. The Mischocyttarus and Polistes species belong to the same tribe (Polistini) and therefore exhibited similar NCPs. These species were separated from the Polybia species in the NCP dendrogram, mainly because the Polybia belong to another tribe (Epiponini). Correlation was observed between the NCPs and the cuticular chemical profiles of females. The findings of the study demonstrated the importance of the NCP for differentiation of species and environments, and the utility of FTIR-PAS for identification of correlations between individuals and nests. The results confirmed the hypothesis that the NCP can be used as an additional tool for intra- and interspecific differentiation in social wasps of the subfamily Polistinae.

Intraspecific variation and influence of diet on the venom chemical profile of the Ectatomma brunneum Smith (Formicidae) ant evaluated by photoacoustic spectroscopy.

Studies of venomous animals have shown that environmental and genetic factors contribute to determining the chemical composition of venom. It is well known that external effects cause differences in the toxicity, concentration, and prey specificity of venom. However, the influence of different factors on the chemical profile of Hymenoptera venom remains little explored. In view of this, the aim of this study was to evaluate intraspecific differences and the influence of diet on the chemical profile of Ectatomma brunneum venom using Fourier transform infrared photoacoustic spectroscopy. For the study of intraspecific variation of the venom, foragers were collected at locations with different environmental conditions, such as urban, intermediate, woodland and monoculture sites. To investigate the influence of diet on the venom, two colonies were sampled in the same area and were maintained in the laboratory under controlled diet conditions and at room temperature. The mid-infrared absorption spectra obtained were interpreted using discriminant function analysis. The results showed significant differences among the chemical profiles of the venoms of individuals from different environments and individuals exposed to a controlled diet in the laboratory, suggesting that venom composition was determined not only by genetic traits inherent to the species, but also by exogenous factors.

[Cost-benefit analysis of ocular examination of patients with rosacea]. / Análise do custo-benefício da avaliação ocular de pacientes portadores de rosácea.

PURPOSE: To observe the main ocular manifestations of patients with rosacea and to evaluate the cost-benefit of supplementary diagnostic examinations. METHODS: Twenty patients with acne rosacea from the Dermatology Service of the São Paulo Federal University (UNIFESP) were interviewed through a questionnaire, submitted to ophthalmologic examination and tested with Schirmer I, fluorescein and rose Bengal staining, impression cytology and conjunctival scrub. The costs of these examinations were abstracted from the Public Health System's values (SUS), Brazilian Medical Association values (AMB) and values charged by a private service. RESULTS: Twenty patients were enrolled initially in the study, but only 16 completed it. Eleven patients were female (55%), 19 were white (95%) and the average age was 56 years. All patients had at least one complaint related to rosacea. The most common symptoms were itching (40%), tearing (35%), foreign body sensation (30%). The most common signs were telangiectasis of lid margins (70%), hyperemia of lid margins (70%), meibomitis (65%) and blepharitis (50%). Most subsidiary examination showed normal results. There was difference of costs between the different paying sources. CONCLUSIONS: The main ocular manifestations in rosacea were related with meibomian gland disease. Considering the subsidiary examination costs and their results, the ophthalmologic check-up presents the best cost-benefit for the patient with rosacea.

Análise do custo-benefício da avaliação ocular de pacientes portadores de rosácea / Cost-benefit analysis of ocular examination of patients with rosacea

OBJETIVO: Observar as principais manifestações oculares de pacientes portadores de rosácea e avaliar o custo-benefício dos exames diagnósticos realizados. MÉTODOS: Vinte pacientes com acne rosácea do Ambulatório de Dermatologia da Universidade Federal de São Paulo (UNIFESP) foram entrevistados por meio de um questionário, submetidos ao exame oftalmológico e aos testes de Schirmer I, fluoresceína, rosa Bengala, citologia de impressão e raspado conjuntival. O levantamento de custos destes exames foi feito a partir da tabela do Sistema Unico de Saúde (SUS), medicina de grupo (AMB 90) e valores cobrados no serviço particular. RESULTADOS: De um total de 20 pacientes que iniciaram o estudo, 16 compareceram a todas as consultas. Houve predomínio do sexo feminino (55 por cento), raça branca (95 por cento) e a média de idade foi de 56 anos. Todos os pacientes apresentaram sinais e sintomas clínicos e os principais foram: prurido (40 por cento), lacrimejamento (35 por cento), sensação de corpo estranho (30 por cento), embaçamento visual (25 por cento), telangiectasia palpebral (70 por cento), hiperemia palpebral (70 por cento), meibomite (65 por cento), blefarite (50 por cento). Os exames subsidiários realizados mostraram-se, em sua maioria, dentro da normalidade. Houve diferença no levantamento de custos das diferentes fontes pagadoras. CONCLUSÕES: As principais manifestações oculares de pacientes portadores de rosácea foram sinais e sintomas relacionados com disfunção das glândulas de Meibomius. Considerando os custos dos exames realizados e os resultados obtidos, concluímos que a consulta oftalmológica é a que apresenta melhor custo-benefício para o paciente portador de rosácea.